Patch from Alejandro Sedeno, somewhat modified by me, which
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index 91bfa88..0616eff 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -1,11 +1,21 @@
+/*
+ * SSH backend.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <assert.h>
+#include <limits.h>
+#include <signal.h>
 
 #include "putty.h"
 #include "tree234.h"
 #include "ssh.h"
+#ifndef NO_GSSAPI
+#include "sshgssc.h"
+#include "sshgss.h"
+#endif
 
 #ifndef FALSE
 #define FALSE 0
 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE            71   /* 0x47 */
 #define SSH1_CMSG_AUTH_CCARD_RESPONSE             72   /* 0x48 */
 
+#define SSH1_AUTH_RHOSTS                          1    /* 0x1 */
+#define SSH1_AUTH_RSA                             2    /* 0x2 */
+#define SSH1_AUTH_PASSWORD                        3    /* 0x3 */
+#define SSH1_AUTH_RHOSTS_RSA                      4    /* 0x4 */
 #define SSH1_AUTH_TIS                             5    /* 0x5 */
 #define SSH1_AUTH_CCARD                           16   /* 0x10 */
 
@@ -77,6 +91,9 @@
 #define SSH2_MSG_KEX_DH_GEX_GROUP                 31   /* 0x1f */
 #define SSH2_MSG_KEX_DH_GEX_INIT                  32   /* 0x20 */
 #define SSH2_MSG_KEX_DH_GEX_REPLY                 33   /* 0x21 */
+#define SSH2_MSG_KEXRSA_PUBKEY                    30    /* 0x1e */
+#define SSH2_MSG_KEXRSA_SECRET                    31    /* 0x1f */
+#define SSH2_MSG_KEXRSA_DONE                      32    /* 0x20 */
 #define SSH2_MSG_USERAUTH_REQUEST                 50   /* 0x32 */
 #define SSH2_MSG_USERAUTH_FAILURE                 51   /* 0x33 */
 #define SSH2_MSG_USERAUTH_SUCCESS                 52   /* 0x34 */
 #define SSH2_MSG_CHANNEL_REQUEST                  98   /* 0x62 */
 #define SSH2_MSG_CHANNEL_SUCCESS                  99   /* 0x63 */
 #define SSH2_MSG_CHANNEL_FAILURE                  100  /* 0x64 */
+#define SSH2_MSG_USERAUTH_GSSAPI_RESPONSE               60
+#define SSH2_MSG_USERAUTH_GSSAPI_TOKEN                  61
+#define SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE      63
+#define SSH2_MSG_USERAUTH_GSSAPI_ERROR                  64
+#define SSH2_MSG_USERAUTH_GSSAPI_ERRTOK                 65
+#define SSH2_MSG_USERAUTH_GSSAPI_MIC                    66
 
 /*
  * Packet type contexts, so that ssh2_pkt_type can correctly decode
  * the ambiguous type numbers back into the correct type strings.
  */
-#define SSH2_PKTCTX_DHGROUP          0x0001
-#define SSH2_PKTCTX_DHGEX            0x0002
-#define SSH2_PKTCTX_KEX_MASK         0x000F
-#define SSH2_PKTCTX_PUBLICKEY        0x0010
-#define SSH2_PKTCTX_PASSWORD         0x0020
-#define SSH2_PKTCTX_KBDINTER         0x0040
-#define SSH2_PKTCTX_AUTH_MASK        0x00F0
+typedef enum {
+    SSH2_PKTCTX_NOKEX,
+    SSH2_PKTCTX_DHGROUP,
+    SSH2_PKTCTX_DHGEX,
+    SSH2_PKTCTX_RSAKEX
+} Pkt_KCtx;
+typedef enum {
+    SSH2_PKTCTX_NOAUTH,
+    SSH2_PKTCTX_PUBLICKEY,
+    SSH2_PKTCTX_PASSWORD,
+    SSH2_PKTCTX_GSSAPI,
+    SSH2_PKTCTX_KBDINTER
+} Pkt_ACtx;
 
 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1  /* 0x1 */
 #define SSH2_DISCONNECT_PROTOCOL_ERROR            2    /* 0x2 */
 
 static const char *const ssh2_disconnect_reasons[] = {
     NULL,
-    "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
-    "SSH_DISCONNECT_PROTOCOL_ERROR",
-    "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
-    "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
-    "SSH_DISCONNECT_MAC_ERROR",
-    "SSH_DISCONNECT_COMPRESSION_ERROR",
-    "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
-    "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
-    "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
-    "SSH_DISCONNECT_CONNECTION_LOST",
-    "SSH_DISCONNECT_BY_APPLICATION",
-    "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
-    "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
-    "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
-    "SSH_DISCONNECT_ILLEGAL_USER_NAME",
+    "host not allowed to connect",
+    "protocol error",
+    "key exchange failed",
+    "host authentication failed",
+    "MAC error",
+    "compression error",
+    "service not available",
+    "protocol version not supported",
+    "host key not verifiable",
+    "connection lost",
+    "by application",
+    "too many connections",
+    "auth cancelled by user",
+    "no more auth methods available",
+    "illegal user name",
 };
 
 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED     1    /* 0x1 */
@@ -165,11 +194,13 @@ static const char *const ssh2_disconnect_reasons[] = {
 #define BUG_SSH2_DERIVEKEY                       32
 #define BUG_SSH2_REKEY                           64
 #define BUG_SSH2_PK_SESSIONID                   128
+#define BUG_SSH2_MAXPKT                                256
+#define BUG_CHOKES_ON_SSH2_IGNORE               512
 
 /*
  * Codes for terminal modes.
  * Most of these are the same in SSH-1 and SSH-2.
- * This list is derived from draft-ietf-secsh-connect-25 and
+ * This list is derived from RFC 4254 and
  * SSH-1 RFC-1.2.31.
  */
 static const struct {
@@ -271,7 +302,8 @@ static unsigned int ssh_tty_parse_boolean(char *s)
 }
 
 #define translate(x) if (type == x) return #x
-#define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
+#define translatek(x,ctx) if (type == x && (pkt_kctx == ctx)) return #x
+#define translatea(x,ctx) if (type == x && (pkt_actx == ctx)) return #x
 static char *ssh1_pkt_type(int type)
 {
     translate(SSH1_MSG_DISCONNECT);
@@ -317,8 +349,14 @@ static char *ssh1_pkt_type(int type)
     translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
     return "unknown";
 }
-static char *ssh2_pkt_type(int pkt_ctx, int type)
+static char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx, int type)
 {
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
     translate(SSH2_MSG_DISCONNECT);
     translate(SSH2_MSG_IGNORE);
     translate(SSH2_MSG_UNIMPLEMENTED);
@@ -327,20 +365,23 @@ static char *ssh2_pkt_type(int pkt_ctx, int type)
     translate(SSH2_MSG_SERVICE_ACCEPT);
     translate(SSH2_MSG_KEXINIT);
     translate(SSH2_MSG_NEWKEYS);
-    translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
-    translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
-    translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
+    translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
+    translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
+    translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
+    translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
     translate(SSH2_MSG_USERAUTH_REQUEST);
     translate(SSH2_MSG_USERAUTH_FAILURE);
     translate(SSH2_MSG_USERAUTH_SUCCESS);
     translate(SSH2_MSG_USERAUTH_BANNER);
-    translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
-    translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
-    translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
-    translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
+    translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
+    translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
+    translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
+    translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
     translate(SSH2_MSG_GLOBAL_REQUEST);
     translate(SSH2_MSG_REQUEST_SUCCESS);
     translate(SSH2_MSG_REQUEST_FAILURE);
@@ -452,20 +493,38 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
  * 
  *  - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
  *    channels.
+ *
+ *  - OUR_V2_BIGWIN is the window size we advertise for the only
+ *    channel in a simple connection.  It must be <= INT_MAX.
+ *
+ *  - OUR_V2_MAXPKT is the official "maximum packet size" we send
+ *    to the remote side. This actually has nothing to do with the
+ *    size of the _packet_, but is instead a limit on the amount
+ *    of data we're willing to receive in a single SSH2 channel
+ *    data message.
+ *
+ *  - OUR_V2_PACKETLIMIT is actually the maximum size of SSH
+ *    _packet_ we're prepared to cope with.  It must be a multiple
+ *    of the cipher block size, and must be at least 35000.
  */
 
 #define SSH1_BUFFER_LIMIT 32768
 #define SSH_MAX_BACKLOG 32768
 #define OUR_V2_WINSIZE 16384
+#define OUR_V2_BIGWIN 0x7fffffff
 #define OUR_V2_MAXPKT 0x4000UL
+#define OUR_V2_PACKETLIMIT 0x9000UL
+
+/* Maximum length of passwords/passphrases (arbitrary) */
+#define SSH_MAX_PASSWORD_LEN 100
 
 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
 
 const static struct ssh_mac *macs[] = {
-    &ssh_hmac_sha1, &ssh_hmac_md5
+    &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
 };
 const static struct ssh_mac *buggymacs[] = {
-    &ssh_hmac_sha1_buggy, &ssh_hmac_md5
+    &ssh_hmac_sha1_buggy, &ssh_hmac_sha1_96_buggy, &ssh_hmac_md5
 };
 
 static void *ssh_comp_none_init(void)
@@ -504,6 +563,14 @@ enum {                                    /* channel types */
 };
 
 /*
+ * little structure to keep track of outstanding WINDOW_ADJUSTs
+ */
+struct winadj {
+    struct winadj *next;
+    unsigned size;
+};
+
+/*
  * 2-3-4 tree storing channels.
  */
 struct ssh_channel {
@@ -523,14 +590,29 @@ struct ssh_channel {
      * A channel is completely finished with when all four bits are set.
      */
     int closes;
+    /*
+     * True if this channel is causing the underlying connection to be
+     * throttled.
+     */
+    int throttling_conn;
     union {
-       struct ssh1_data_channel {
-           int throttling;
-       } v1;
        struct ssh2_data_channel {
            bufchain outbuffer;
            unsigned remwindow, remmaxpkt;
-           unsigned locwindow;
+           /* locwindow is signed so we can cope with excess data. */
+           int locwindow, locmaxwin;
+           /*
+            * remlocwin is the amount of local window that we think
+            * the remote end had available to it after it sent the
+            * last data packet or window adjust ack.
+            */
+           int remlocwin;
+           /*
+            * These store the list of window adjusts that haven't
+            * been acked.
+            */
+           struct winadj *winadj_head, *winadj_tail;
+           enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
        } v2;
     } v;
     union {
@@ -637,7 +719,7 @@ static void ssh_special(void *handle, Telnet_Special);
 static int ssh2_try_send(struct ssh_channel *c);
 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
-static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
+static void ssh2_set_window(struct ssh_channel *c, int newwin);
 static int ssh_sendbuffer(void *handle);
 static int ssh_do_close(Ssh ssh, int notify_exit);
 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
@@ -705,7 +787,7 @@ struct ssh_tag {
     void *cs_comp_ctx, *sc_comp_ctx;
     const struct ssh_kex *kex;
     const struct ssh_signkey *hostkey;
-    unsigned char v2_session_id[20];
+    unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
     int v2_session_id_len;
     void *kex_ctx;
 
@@ -721,6 +803,7 @@ struct ssh_tag {
 
     tree234 *channels;                /* indexed by local id */
     struct ssh_channel *mainchan;      /* primary session channel */
+    int ncmode;                               /* is primary channel direct-tcpip? */
     int exitcode;
     int close_expected;
     int clean_exit;
@@ -752,20 +835,14 @@ struct ssh_tag {
     int fallback_cmd;
 
     bufchain banner;   /* accumulates banners during do_ssh2_authconn */
-    /*
-     * Used for username and password input.
-     */
-    char *userpass_input_buffer;
-    int userpass_input_buflen;
-    int userpass_input_bufpos;
-    int userpass_input_echo;
 
-    int pkt_ctx;
+    Pkt_KCtx pkt_kctx;
+    Pkt_ACtx pkt_actx;
 
-    void *x11auth;
+    struct X11Display *x11disp;
 
     int version;
-    int v1_throttle_count;
+    int conn_throttle_count;
     int overall_bufsize;
     int throttled_all;
     int v1_stdout_throttling;
@@ -848,6 +925,11 @@ struct ssh_tag {
     int kex_in_progress;
     long next_rekey, last_rekey;
     char *deferred_rekey_reason;    /* points to STATIC string; don't free */
+
+    /*
+     * Fully qualified host name, which we need if doing GSSAPI.
+     */
+    char *fullhostname;
 };
 
 #define logevent(s) logevent(ssh->frontend, s)
@@ -1046,27 +1128,28 @@ static int alloc_channel_id(Ssh ssh)
     return low + 1 + CHANNEL_NUMBER_OFFSET;
 }
 
+static void c_write_stderr(int trusted, const char *buf, int len)
+{
+    int i;
+    for (i = 0; i < len; i++)
+       if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
+           fputc(buf[i], stderr);
+}
+
 static void c_write(Ssh ssh, const char *buf, int len)
 {
-    if ((flags & FLAG_STDERR)) {
-       int i;
-       for (i = 0; i < len; i++)
-           if (buf[i] != '\r')
-               fputc(buf[i], stderr);
-       return;
-    }
-    from_backend(ssh->frontend, 1, buf, len);
+    if (flags & FLAG_STDERR)
+       c_write_stderr(1, buf, len);
+    else
+       from_backend(ssh->frontend, 1, buf, len);
 }
 
 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
 {
-    int i;
-    for (i = 0; i < len; i++) {
-       if (buf[i] == '\n')
-           c_write(ssh, "\r\n", 2);
-       else if ((buf[i] & 0x60) || (buf[i] == '\r'))
-           c_write(ssh, buf + i, 1);
-    }
+    if (flags & FLAG_STDERR)
+       c_write_stderr(0, buf, len);
+    else
+       from_backend_untrusted(ssh->frontend, buf, len);
 }
 
 static void c_write_str(Ssh ssh, const char *buf)
@@ -1204,9 +1287,9 @@ static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
            /* "Session data" packets - omit the data field */
            if ((st->pktin->type == SSH1_SMSG_STDOUT_DATA) ||
                (st->pktin->type == SSH1_SMSG_STDERR_DATA)) {
-               do_blank = TRUE; blank_prefix = 0;
-           } else if (st->pktin->type == SSH1_MSG_CHANNEL_DATA) {
                do_blank = TRUE; blank_prefix = 4;
+           } else if (st->pktin->type == SSH1_MSG_CHANNEL_DATA) {
+               do_blank = TRUE; blank_prefix = 8;
            }
            if (do_blank) {
                blank.offset = blank_prefix;
@@ -1219,7 +1302,7 @@ static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
                   PKT_INCOMING, st->pktin->type,
                   ssh1_pkt_type(st->pktin->type),
                   st->pktin->body, st->pktin->length,
-                  nblanks, &blank);
+                  nblanks, &blank, NULL);
     }
 
     crFinish(st->pktin);
@@ -1241,90 +1324,162 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
        st->cipherblk = 8;
     if (st->cipherblk < 8)
        st->cipherblk = 8;
+    st->maclen = ssh->scmac ? ssh->scmac->len : 0;
 
-    st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
+    if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
+       ssh->scmac) {
+       /*
+        * When dealing with a CBC-mode cipher, we want to avoid the
+        * possibility of an attacker's tweaking the ciphertext stream
+        * so as to cause us to feed the same block to the block
+        * cipher more than once and thus leak information
+        * (VU#958563).  The way we do this is not to take any
+        * decisions on the basis of anything we've decrypted until
+        * we've verified it with a MAC.  That includes the packet
+        * length, so we just read data and check the MAC repeatedly,
+        * and when the MAC passes, see if the length we've got is
+        * plausible.
+        */
 
-    /*
-     * Acquire and decrypt the first block of the packet. This will
-     * contain the length and padding details.
-     */
-    for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
-       while ((*datalen) == 0)
-           crReturn(NULL);
-       st->pktin->data[st->i] = *(*data)++;
-       (*datalen)--;
-    }
+       /* May as well allocate the whole lot now. */
+       st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
+                               unsigned char);
 
-    if (ssh->sccipher)
-       ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
-                              st->pktin->data, st->cipherblk);
+       /* Read an amount corresponding to the MAC. */
+       for (st->i = 0; st->i < st->maclen; st->i++) {
+           while ((*datalen) == 0)
+               crReturn(NULL);
+           st->pktin->data[st->i] = *(*data)++;
+           (*datalen)--;
+       }
 
-    /*
-     * Now get the length and padding figures.
-     */
-    st->len = GET_32BIT(st->pktin->data);
-    st->pad = st->pktin->data[4];
+       st->packetlen = 0;
+       {
+           unsigned char seq[4];
+           ssh->scmac->start(ssh->sc_mac_ctx);
+           PUT_32BIT(seq, st->incoming_sequence);
+           ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
+       }
 
-    /*
-     * _Completely_ silly lengths should be stomped on before they
-     * do us any more damage.
-     */
-    if (st->len < 0 || st->len > 35000 || st->pad < 4 ||
-       st->len - st->pad < 1 || (st->len + 4) % st->cipherblk != 0) {
-       bombout(("Incoming packet was garbled on decryption"));
-       ssh_free_packet(st->pktin);
-       crStop(NULL);
-    }
+       for (;;) { /* Once around this loop per cipher block. */
+           /* Read another cipher-block's worth, and tack it onto the end. */
+           for (st->i = 0; st->i < st->cipherblk; st->i++) {
+               while ((*datalen) == 0)
+                   crReturn(NULL);
+               st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
+               (*datalen)--;
+           }
+           /* Decrypt one more block (a little further back in the stream). */
+           ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
+                                  st->pktin->data + st->packetlen,
+                                  st->cipherblk);
+           /* Feed that block to the MAC. */
+           ssh->scmac->bytes(ssh->sc_mac_ctx,
+                             st->pktin->data + st->packetlen, st->cipherblk);
+           st->packetlen += st->cipherblk;
+           /* See if that gives us a valid packet. */
+           if (ssh->scmac->verresult(ssh->sc_mac_ctx,
+                                     st->pktin->data + st->packetlen) &&
+               (st->len = GET_32BIT(st->pktin->data)) + 4 == st->packetlen)
+                   break;
+           if (st->packetlen >= OUR_V2_PACKETLIMIT) {
+               bombout(("No valid incoming packet found"));
+               ssh_free_packet(st->pktin);
+               crStop(NULL);
+           }       
+       }
+       st->pktin->maxlen = st->packetlen + st->maclen;
+       st->pktin->data = sresize(st->pktin->data,
+                                 st->pktin->maxlen + APIEXTRA,
+                                 unsigned char);
+    } else {
+       st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
 
-    /*
-     * This enables us to deduce the payload length.
-     */
-    st->payload = st->len - st->pad - 1;
+       /*
+        * Acquire and decrypt the first block of the packet. This will
+        * contain the length and padding details.
+        */
+       for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
+           while ((*datalen) == 0)
+               crReturn(NULL);
+           st->pktin->data[st->i] = *(*data)++;
+           (*datalen)--;
+       }
 
-    st->pktin->length = st->payload + 5;
+       if (ssh->sccipher)
+           ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
+                                  st->pktin->data, st->cipherblk);
 
-    /*
-     * So now we can work out the total packet length.
-     */
-    st->packetlen = st->len + 4;
-    st->maclen = ssh->scmac ? ssh->scmac->len : 0;
+       /*
+        * Now get the length figure.
+        */
+       st->len = GET_32BIT(st->pktin->data);
 
-    /*
-     * Allocate memory for the rest of the packet.
-     */
-    st->pktin->maxlen = st->packetlen + st->maclen;
-    st->pktin->data = sresize(st->pktin->data,
-                             st->pktin->maxlen + APIEXTRA,
-                             unsigned char);
+       /*
+        * _Completely_ silly lengths should be stomped on before they
+        * do us any more damage.
+        */
+       if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
+           (st->len + 4) % st->cipherblk != 0) {
+           bombout(("Incoming packet was garbled on decryption"));
+           ssh_free_packet(st->pktin);
+           crStop(NULL);
+       }
 
-    /*
-     * Read and decrypt the remainder of the packet.
-     */
-    for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
-        st->i++) {
-       while ((*datalen) == 0)
-           crReturn(NULL);
-       st->pktin->data[st->i] = *(*data)++;
-       (*datalen)--;
-    }
-    /* Decrypt everything _except_ the MAC. */
-    if (ssh->sccipher)
-       ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
-                              st->pktin->data + st->cipherblk,
-                              st->packetlen - st->cipherblk);
+       /*
+        * So now we can work out the total packet length.
+        */
+       st->packetlen = st->len + 4;
 
-    st->pktin->encrypted_len = st->packetlen;
+       /*
+        * Allocate memory for the rest of the packet.
+        */
+       st->pktin->maxlen = st->packetlen + st->maclen;
+       st->pktin->data = sresize(st->pktin->data,
+                                 st->pktin->maxlen + APIEXTRA,
+                                 unsigned char);
 
-    /*
-     * Check the MAC.
-     */
-    if (ssh->scmac
-       && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data, st->len + 4,
-                              st->incoming_sequence)) {
-       bombout(("Incorrect MAC received on packet"));
+       /*
+        * Read and decrypt the remainder of the packet.
+        */
+       for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
+            st->i++) {
+           while ((*datalen) == 0)
+               crReturn(NULL);
+           st->pktin->data[st->i] = *(*data)++;
+           (*datalen)--;
+       }
+       /* Decrypt everything _except_ the MAC. */
+       if (ssh->sccipher)
+           ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
+                                  st->pktin->data + st->cipherblk,
+                                  st->packetlen - st->cipherblk);
+
+       /*
+        * Check the MAC.
+        */
+       if (ssh->scmac
+           && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
+                                  st->len + 4, st->incoming_sequence)) {
+           bombout(("Incorrect MAC received on packet"));
+           ssh_free_packet(st->pktin);
+           crStop(NULL);
+       }
+    }
+    /* Get and sanity-check the amount of random padding. */
+    st->pad = st->pktin->data[4];
+    if (st->pad < 4 || st->len - st->pad < 1) {
+       bombout(("Invalid padding length on received packet"));
        ssh_free_packet(st->pktin);
        crStop(NULL);
     }
+    /*
+     * This enables us to deduce the payload length.
+     */
+    st->payload = st->len - st->pad - 1;
+
+    st->pktin->length = st->payload + 5;
+    st->pktin->encrypted_len = st->packetlen;
 
     st->pktin->sequence = st->incoming_sequence++;
 
@@ -1364,9 +1519,9 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
            int do_blank = FALSE, blank_prefix = 0;
            /* "Session data" packets - omit the data field */
            if (st->pktin->type == SSH2_MSG_CHANNEL_DATA) {
-               do_blank = TRUE; blank_prefix = 4;
-           } else if (st->pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
                do_blank = TRUE; blank_prefix = 8;
+           } else if (st->pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
+               do_blank = TRUE; blank_prefix = 12;
            }
            if (do_blank) {
                blank.offset = blank_prefix;
@@ -1376,9 +1531,10 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
            }
        }
        log_packet(ssh->logctx, PKT_INCOMING, st->pktin->type,
-                  ssh2_pkt_type(ssh->pkt_ctx, st->pktin->type),
+                  ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
+                                st->pktin->type),
                   st->pktin->data+6, st->pktin->length-6,
-                  nblanks, &blank);
+                  nblanks, &blank, &st->pktin->sequence);
     }
 
     crFinish(st->pktin);
@@ -1403,7 +1559,7 @@ static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
        log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
                   ssh1_pkt_type(pkt->data[12]),
                   pkt->body, pkt->length - (pkt->body - pkt->data),
-                  pkt->nblanks, pkt->blanks);
+                  pkt->nblanks, pkt->blanks, NULL);
     sfree(pkt->blanks); pkt->blanks = NULL;
     pkt->nblanks = 0;
 
@@ -1413,6 +1569,7 @@ static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
        zlib_compress_block(ssh->cs_comp_ctx,
                            pkt->data + 12, pkt->length - 12,
                            &compblk, &complen);
+       ssh_pkt_ensure(pkt, complen + 2);   /* just in case it's got bigger */
        memcpy(pkt->data + 12, compblk, complen);
        sfree(compblk);
        pkt->length = complen + 12;
@@ -1439,11 +1596,19 @@ static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
     return biglen + 4;         /* len(length+padding+type+data+CRC) */
 }
 
+static int s_write(Ssh ssh, void *data, int len)
+{
+    if (ssh->logctx)
+       log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
+                  0, NULL, NULL);
+    return sk_write(ssh->s, (char *)data, len);
+}
+
 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
 {
     int len, backlog, offset;
     len = s_wrpkt_prepare(ssh, pkt, &offset);
-    backlog = sk_write(ssh->s, (char *)pkt->data + offset, len);
+    backlog = s_write(ssh, pkt->data + offset, len);
     if (backlog > SSH_MAX_BACKLOG)
        ssh_throttle_all(ssh, 1, backlog);
     ssh_free_packet(pkt);
@@ -1480,6 +1645,7 @@ static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
 
     while ((argtype = va_arg(ap, int)) != PKT_END) {
        unsigned char *argp, argchar;
+       char *sargp;
        unsigned long argint;
        int arglen;
        switch (argtype) {
@@ -1498,8 +1664,8 @@ static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
            ssh_pkt_adddata(pkt, argp, arglen);
            break;
          case PKT_STR:
-           argp = va_arg(ap, unsigned char *);
-           ssh_pkt_addstring(pkt, argp);
+           sargp = va_arg(ap, char *);
+           ssh_pkt_addstring(pkt, sargp);
            break;
          case PKT_BIGNUM:
            bn = va_arg(ap, Bignum);
@@ -1587,7 +1753,7 @@ static void ssh_pkt_ensure(struct Packet *pkt, int length)
 {
     if (pkt->maxlen < length) {
        unsigned char *body = pkt->body;
-       int offset = body ? pkt->data - body : 0;
+       int offset = body ? body - pkt->data : 0;
        pkt->maxlen = length + 256;
        pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
        if (body) pkt->body = pkt->data + offset;
@@ -1645,7 +1811,7 @@ static void ssh_pkt_addstring(struct Packet *pkt, char *data)
 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
 {
     int len = ssh1_bignum_length(b);
-    unsigned char *data = snewn(len, char);
+    unsigned char *data = snewn(len, unsigned char);
     (void) ssh1_write_bignum(data, b);
     ssh_pkt_adddata(pkt, data, len);
     sfree(data);
@@ -1697,10 +1863,10 @@ static struct Packet *ssh1_pkt_init(int pkt_type)
 static struct Packet *ssh2_pkt_init(int pkt_type)
 {
     struct Packet *pkt = ssh_new_packet();
-    pkt->length = 5;
+    pkt->length = 5; /* space for packet length + padding length */
     pkt->forcepad = 0;
     ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
-    pkt->body = pkt->data + pkt->length;
+    pkt->body = pkt->data + pkt->length; /* after packet type */
     return pkt;
 }
 
@@ -1715,9 +1881,9 @@ static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
 
     if (ssh->logctx)
        log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
-                  ssh2_pkt_type(ssh->pkt_ctx, pkt->data[5]),
+                  ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
                   pkt->body, pkt->length - (pkt->body - pkt->data),
-                  pkt->nblanks, pkt->blanks);
+                  pkt->nblanks, pkt->blanks, &ssh->v2_outgoing_sequence);
     sfree(pkt->blanks); pkt->blanks = NULL;
     pkt->nblanks = 0;
 
@@ -1827,7 +1993,7 @@ static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
        return;
     }
     len = ssh2_pkt_construct(ssh, pkt);
-    backlog = sk_write(ssh->s, (char *)pkt->data, len);
+    backlog = s_write(ssh, pkt->data, len);
     if (backlog > SSH_MAX_BACKLOG)
        ssh_throttle_all(ssh, 1, backlog);
 
@@ -1847,12 +2013,14 @@ static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
 {
     int len;
     if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
-       ssh->deferred_len == 0 && !noignore) {
+       ssh->deferred_len == 0 && !noignore &&
+       !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
        /*
         * Interpose an SSH_MSG_IGNORE to ensure that user data don't
         * get encrypted with a known IV.
         */
        struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
+       ssh2_pkt_addstring_start(ipkt);
        ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
     }
     len = ssh2_pkt_construct(ssh, pkt);
@@ -1895,7 +2063,6 @@ static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
        ssh2_pkt_send_noqueue(ssh, pkt);
 }
 
-#if 0 /* disused */
 /*
  * Either queue or defer a packet, depending on whether queueing is
  * set.
@@ -1907,7 +2074,6 @@ static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
     else
        ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
 }
-#endif
 
 /*
  * Send the whole deferred data block constructed by
@@ -1925,8 +2091,7 @@ static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
 static void ssh_pkt_defersend(Ssh ssh)
 {
     int backlog;
-    backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
-                      ssh->deferred_len);
+    backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
     ssh->deferred_len = ssh->deferred_size = 0;
     sfree(ssh->deferred_send_data);
     ssh->deferred_send_data = NULL;
@@ -1942,6 +2107,75 @@ static void ssh_pkt_defersend(Ssh ssh)
 }
 
 /*
+ * Send a packet whose length needs to be disguised (typically
+ * passwords or keyboard-interactive responses).
+ */
+static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
+                                      int padsize)
+{
+#if 0
+    if (0) {
+       /*
+        * The simplest way to do this is to adjust the
+        * variable-length padding field in the outgoing packet.
+        * 
+        * Currently compiled out, because some Cisco SSH servers
+        * don't like excessively padded packets (bah, why's it
+        * always Cisco?)
+        */
+       pkt->forcepad = padsize;
+       ssh2_pkt_send(ssh, pkt);
+    } else
+#endif
+    {
+       /*
+        * If we can't do that, however, an alternative approach is
+        * to use the pkt_defer mechanism to bundle the packet
+        * tightly together with an SSH_MSG_IGNORE such that their
+        * combined length is a constant. So first we construct the
+        * final form of this packet and defer its sending.
+        */
+       ssh2_pkt_defer(ssh, pkt);
+
+       /*
+        * Now construct an SSH_MSG_IGNORE which includes a string
+        * that's an exact multiple of the cipher block size. (If
+        * the cipher is NULL so that the block size is
+        * unavailable, we don't do this trick at all, because we
+        * gain nothing by it.)
+        */
+       if (ssh->cscipher &&
+           !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
+           int stringlen, i;
+
+           stringlen = (256 - ssh->deferred_len);
+           stringlen += ssh->cscipher->blksize - 1;
+           stringlen -= (stringlen % ssh->cscipher->blksize);
+           if (ssh->cscomp) {
+               /*
+                * Temporarily disable actual compression, so we
+                * can guarantee to get this string exactly the
+                * length we want it. The compression-disabling
+                * routine should return an integer indicating how
+                * many bytes we should adjust our string length
+                * by.
+                */
+               stringlen -=
+                   ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
+           }
+           pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
+           ssh2_pkt_addstring_start(pkt);
+           for (i = 0; i < stringlen; i++) {
+               char c = (char) random_byte();
+               ssh2_pkt_addstring_data(pkt, &c, 1);
+           }
+           ssh2_pkt_defer(ssh, pkt);
+       }
+       ssh_pkt_defersend(ssh);
+    }
+}
+
+/*
  * Send all queued SSH-2 packets. We send them by means of
  * ssh2_pkt_defer_noqueue(), in case they included a pair of
  * packets that needed to be lumped together.
@@ -2158,6 +2392,13 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     ssh->remote_bugs = 0;
 
+    /*
+     * General notes on server version strings:
+     *  - Not all servers reporting "Cisco-1.25" have all the bugs listed
+     *    here -- in particular, we've heard of one that's perfectly happy
+     *    with SSH1_MSG_IGNOREs -- but this string never seems to change,
+     *    so we can't distinguish them.
+     */
     if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
        (ssh->cfg.sshbug_ignore1 == AUTO &&
         (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
@@ -2260,6 +2501,26 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        ssh->remote_bugs |= BUG_SSH2_REKEY;
        logevent("We believe remote version has SSH-2 rekey bug");
     }
+
+    if (ssh->cfg.sshbug_maxpkt2 == FORCE_ON ||
+       (ssh->cfg.sshbug_maxpkt2 == AUTO &&
+        (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
+          wc_match("1.36 sshlib: GlobalScape", imp)))) {
+       /*
+        * This version ignores our makpkt and needs to be throttled.
+        */
+       ssh->remote_bugs |= BUG_SSH2_MAXPKT;
+       logevent("We believe remote version ignores SSH-2 maximum packet size");
+    }
+
+    if (ssh->cfg.sshbug_ignore2 == FORCE_ON) {
+       /*
+        * Servers that don't support SSH2_MSG_IGNORE. Currently,
+        * none detected automatically.
+        */
+       ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
+       logevent("We believe remote version has SSH-2 ignore bug");
+    }
 }
 
 /*
@@ -2285,6 +2546,47 @@ static void ssh_fix_verstring(char *str)
     }
 }
 
+/*
+ * Send an appropriate SSH version string.
+ */
+static void ssh_send_verstring(Ssh ssh, char *svers)
+{
+    char *verstring;
+
+    if (ssh->version == 2) {
+       /*
+        * Construct a v2 version string.
+        */
+       verstring = dupprintf("SSH-2.0-%s\015\012", sshver);
+    } else {
+       /*
+        * Construct a v1 version string.
+        */
+       verstring = dupprintf("SSH-%s-%s\012",
+                             (ssh_versioncmp(svers, "1.5") <= 0 ?
+                              svers : "1.5"),
+                             sshver);
+    }
+
+    ssh_fix_verstring(verstring);
+
+    if (ssh->version == 2) {
+       size_t len;
+       /*
+        * Record our version string.
+        */
+       len = strcspn(verstring, "\015\012");
+       ssh->v_c = snewn(len + 1, char);
+       memcpy(ssh->v_c, verstring, len);
+       ssh->v_c[len] = 0;
+    }
+
+    logeventf(ssh, "We claim version: %.*s",
+             strcspn(verstring, "\015\012"), verstring);
+    s_write(ssh, verstring, strlen(verstring));
+    sfree(verstring);
+}
+
 static int do_ssh_init(Ssh ssh, unsigned char c)
 {
     struct do_ssh_init_state {
@@ -2363,65 +2665,43 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        crStop(0);
     }
 
-    {
-        char *verstring;
+    if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1))
+       ssh->version = 2;
+    else
+       ssh->version = 1;
 
-        if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
-            /*
-             * Construct a v2 version string.
-             */
-            verstring = dupprintf("SSH-2.0-%s\015\012", sshver);
-            ssh->version = 2;
-        } else {
-            /*
-             * Construct a v1 version string.
-             */
-            verstring = dupprintf("SSH-%s-%s\012",
-                                  (ssh_versioncmp(s->version, "1.5") <= 0 ?
-                                   s->version : "1.5"),
-                                  sshver);
-            ssh->version = 1;
-        }
+    logeventf(ssh, "Using SSH protocol version %d", ssh->version);
 
-        ssh_fix_verstring(verstring);
+    /* Send the version string, if we haven't already */
+    if (ssh->cfg.sshprot != 3)
+       ssh_send_verstring(ssh, s->version);
 
-        if (ssh->version == 2) {
-           size_t len;
-            /*
-             * Hash our version string and their version string.
-             */
-           len = strcspn(verstring, "\015\012");
-           ssh->v_c = snewn(len + 1, char);
-           memcpy(ssh->v_c, verstring, len);
-           ssh->v_c[len] = 0;
-           len = strcspn(s->vstring, "\015\012");
-           ssh->v_s = snewn(len + 1, char);
-           memcpy(ssh->v_s, s->vstring, len);
-           ssh->v_s[len] = 0;
+    if (ssh->version == 2) {
+       size_t len;
+       /*
+        * Record their version string.
+        */
+       len = strcspn(s->vstring, "\015\012");
+       ssh->v_s = snewn(len + 1, char);
+       memcpy(ssh->v_s, s->vstring, len);
+       ssh->v_s[len] = 0;
            
-            /*
-             * Initialise SSH-2 protocol.
-             */
-            ssh->protocol = ssh2_protocol;
-            ssh2_protocol_setup(ssh);
-            ssh->s_rdpkt = ssh2_rdpkt;
-        } else {
-            /*
-             * Initialise SSH-1 protocol.
-             */
-            ssh->protocol = ssh1_protocol;
-            ssh1_protocol_setup(ssh);
-            ssh->s_rdpkt = ssh1_rdpkt;
-        }
-        logeventf(ssh, "We claim version: %.*s",
-                  strcspn(verstring, "\015\012"), verstring);
-       sk_write(ssh->s, verstring, strlen(verstring));
-        sfree(verstring);
-       if (ssh->version == 2)
-           do_ssh2_transport(ssh, NULL, -1, NULL);
+       /*
+        * Initialise SSH-2 protocol.
+        */
+       ssh->protocol = ssh2_protocol;
+       ssh2_protocol_setup(ssh);
+       ssh->s_rdpkt = ssh2_rdpkt;
+    } else {
+       /*
+        * Initialise SSH-1 protocol.
+        */
+       ssh->protocol = ssh1_protocol;
+       ssh1_protocol_setup(ssh);
+       ssh->s_rdpkt = ssh1_rdpkt;
     }
-
-    logeventf(ssh, "Using SSH protocol version %d", ssh->version);
+    if (ssh->version == 2)
+       do_ssh2_transport(ssh, NULL, -1, NULL);
 
     update_specials_menu(ssh->frontend);
     ssh->state = SSH_STATE_BEFORE_SIZE;
@@ -2435,7 +2715,9 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
 static void ssh_process_incoming_data(Ssh ssh,
                                      unsigned char **data, int *datalen)
 {
-    struct Packet *pktin = ssh->s_rdpkt(ssh, data, datalen);
+    struct Packet *pktin;
+
+    pktin = ssh->s_rdpkt(ssh, data, datalen);
     if (pktin) {
        ssh->protocol(ssh, NULL, 0, pktin);
        ssh_free_packet(pktin);
@@ -2478,6 +2760,11 @@ static void ssh_set_frozen(Ssh ssh, int frozen)
 
 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
 {
+    /* Log raw data, if we're in that mode. */
+    if (ssh->logctx)
+       log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
+                  0, NULL, NULL);
+
     crBegin(ssh->ssh_gotdata_crstate);
 
     /*
@@ -2579,6 +2866,8 @@ static int ssh_do_close(Ssh ssh, int notify_exit)
            del234(ssh->portfwds, pf); /* moving next one to index 0 */
            free_portfwd(pf);
        }
+       freetree234(ssh->portfwds);
+       ssh->portfwds = NULL;
     }
 
     return ret;
@@ -2614,6 +2903,9 @@ static int ssh_closing(Plug plug, const char *error_msg, int error_code,
            error_msg = "Server closed network connection";
     }
 
+    if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
+       ssh->exitcode = 0;
+
     if (need_notify)
         notify_remote_exit(ssh->frontend);
 
@@ -2666,12 +2958,30 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
     SockAddr addr;
     const char *err;
 
-    ssh->savedhost = snewn(1 + strlen(host), char);
-    strcpy(ssh->savedhost, host);
+    if (*ssh->cfg.loghost) {
+       char *colon;
+
+       ssh->savedhost = dupstr(ssh->cfg.loghost);
+       ssh->savedport = 22;           /* default ssh port */
 
-    if (port < 0)
-       port = 22;                     /* default ssh port */
-    ssh->savedport = port;
+       /*
+        * A colon suffix on savedhost also lets us affect
+        * savedport.
+        * 
+        * (FIXME: do something about IPv6 address literals here.)
+        */
+       colon = strrchr(ssh->savedhost, ':');
+       if (colon) {
+           *colon++ = '\0';
+           if (*colon)
+               ssh->savedport = atoi(colon);
+       }
+    } else {
+       ssh->savedhost = dupstr(host);
+       if (port < 0)
+           port = 22;                 /* default ssh port */
+       ssh->savedport = port;
+    }
 
     /*
      * Try to find host.
@@ -2685,6 +2995,7 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
        sk_addr_free(addr);
        return err;
     }
+    ssh->fullhostname = dupstr(*realhost);   /* save in case of GSSAPI */
 
     /*
      * Open socket.
@@ -2698,20 +3009,39 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
        return err;
     }
 
+    /*
+     * If the SSH version number's fixed, set it now, and if it's SSH-2,
+     * send the version string too.
+     */
+    if (ssh->cfg.sshprot == 0)
+       ssh->version = 1;
+    if (ssh->cfg.sshprot == 3) {
+       ssh->version = 2;
+       ssh_send_verstring(ssh, NULL);
+    }
+
+    /*
+     * loghost, if configured, overrides realhost.
+     */
+    if (*ssh->cfg.loghost) {
+       sfree(*realhost);
+       *realhost = dupstr(ssh->cfg.loghost);
+    }
+
     return NULL;
 }
 
 /*
  * Throttle or unthrottle the SSH connection.
  */
-static void ssh1_throttle(Ssh ssh, int adjust)
+static void ssh_throttle_conn(Ssh ssh, int adjust)
 {
-    int old_count = ssh->v1_throttle_count;
-    ssh->v1_throttle_count += adjust;
-    assert(ssh->v1_throttle_count >= 0);
-    if (ssh->v1_throttle_count && !old_count) {
+    int old_count = ssh->conn_throttle_count;
+    ssh->conn_throttle_count += adjust;
+    assert(ssh->conn_throttle_count >= 0);
+    if (ssh->conn_throttle_count && !old_count) {
        ssh_set_frozen(ssh, 1);
-    } else if (!ssh->v1_throttle_count && old_count) {
+    } else if (!ssh->conn_throttle_count && old_count) {
        ssh_set_frozen(ssh, 0);
     }
 }
@@ -2751,78 +3081,6 @@ static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
     }
 }
 
-/*
- * Username and password input, abstracted off into routines
- * reusable in several places - even between SSH-1 and SSH-2.
- */
-
-/* Set up a username or password input loop on a given buffer. */
-static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
-{
-    ssh->userpass_input_buffer = buffer;
-    ssh->userpass_input_buflen = buflen;
-    ssh->userpass_input_bufpos = 0;
-    ssh->userpass_input_echo = echo;
-}
-
-/*
- * Process some terminal data in the course of username/password
- * input. Returns >0 for success (line of input returned in
- * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
- * for inconclusive (keep waiting for more input please).
- */
-static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
-{
-    char c;
-
-    while (inlen--) {
-       switch (c = *in++) {
-         case 10:
-         case 13:
-           ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
-           ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
-           return +1;
-           break;
-         case 8:
-         case 127:
-           if (ssh->userpass_input_bufpos > 0) {
-               if (ssh->userpass_input_echo)
-                   c_write_str(ssh, "\b \b");
-               ssh->userpass_input_bufpos--;
-           }
-           break;
-         case 21:
-         case 27:
-           while (ssh->userpass_input_bufpos > 0) {
-               if (ssh->userpass_input_echo)
-                   c_write_str(ssh, "\b \b");
-               ssh->userpass_input_bufpos--;
-           }
-           break;
-         case 3:
-         case 4:
-           return -1;
-           break;
-         default:
-           /*
-            * This simplistic check for printability is disabled
-            * when we're doing password input, because some people
-            * have control characters in their passwords.o
-            */
-           if ((!ssh->userpass_input_echo ||
-                (c >= ' ' && c <= '~') ||
-                ((unsigned char) c >= 160))
-               && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
-               ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
-               if (ssh->userpass_input_echo)
-                   c_write(ssh, &c, 1);
-           }
-           break;
-       }
-    }
-    return 0;
-}
-
 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
 {
     Ssh ssh = (Ssh) sshv;
@@ -2871,8 +3129,8 @@ static void ssh_agentf_callback(void *cv, void *reply, int replylen)
     } else {
        send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
                    PKT_INT, c->remoteid,
-                   PKTT_DATA,
                    PKT_INT, replylen,
+                   PKTT_DATA,
                    PKT_DATA, sentreply, replylen,
                    PKTT_OTHER,
                    PKT_END);
@@ -2935,9 +3193,9 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
        char username[100];
        void *publickey_blob;
        int publickey_bloblen;
-       char password[100];
-       char prompt[200];
-       int pos;
+       char *publickey_comment;
+       int publickey_encrypted;
+       prompts_t *cur_prompt;
        char c;
        int pwpkt_type;
        unsigned char request[5], *response, *p;
@@ -2993,6 +3251,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
     ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
     s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
     s->supported_auths_mask = ssh_pkt_getuint32(pktin);
+    if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
+       s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
 
     ssh->v1_local_protoflags =
        ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
@@ -3199,72 +3459,103 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
 
     logevent("Successfully started encryption");
 
-    fflush(stdout);
+    fflush(stdout); /* FIXME eh? */
     {
-       if (!*ssh->cfg.username) {
-           if (ssh_get_line && !ssh_getline_pw_only) {
-               if (!ssh_get_line("login as: ",
-                                 s->username, sizeof(s->username), FALSE)) {
-                   /*
-                    * get_line failed to get a username.
-                    * Terminate.
-                    */
-                   ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
-                   crStop(1);
-               }
-           } else {
-               int ret;               /* need not be kept over crReturn */
-               c_write_str(ssh, "login as: ");
+       if (!get_remote_username(&ssh->cfg, s->username,
+                                sizeof(s->username))) {
+           int ret; /* need not be kept over crReturn */
+           s->cur_prompt = new_prompts(ssh->frontend);
+           s->cur_prompt->to_server = TRUE;
+           s->cur_prompt->name = dupstr("SSH login name");
+           add_prompt(s->cur_prompt, dupstr("login as: "), TRUE,
+                      lenof(s->username)); 
+           ret = get_userpass_input(s->cur_prompt, NULL, 0);
+           while (ret < 0) {
                ssh->send_ok = 1;
-
-               setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
-               do {
-                   crWaitUntil(!pktin);
-                   ret = process_userpass_input(ssh, in, inlen);
-               } while (ret == 0);
-               if (ret < 0)
-                   cleanup_exit(0);
-               c_write_str(ssh, "\r\n");
+               crWaitUntil(!pktin);
+               ret = get_userpass_input(s->cur_prompt, in, inlen);
+               ssh->send_ok = 0;
            }
-       } else {
-           strncpy(s->username, ssh->cfg.username, sizeof(s->username));
-           s->username[sizeof(s->username)-1] = '\0';
+           if (!ret) {
+               /*
+                * Failed to get a username. Terminate.
+                */
+               free_prompts(s->cur_prompt);
+               ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
+               crStop(0);
+           }
+           memcpy(s->username, s->cur_prompt->prompts[0]->result,
+                  lenof(s->username));
+           free_prompts(s->cur_prompt);
        }
 
        send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
        {
-           char userlog[22 + sizeof(s->username)];
-           sprintf(userlog, "Sent username \"%s\"", s->username);
+           char *userlog = dupprintf("Sent username \"%s\"", s->username);
            logevent(userlog);
            if (flags & FLAG_INTERACTIVE &&
                (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
-               strcat(userlog, "\r\n");
                c_write_str(ssh, userlog);
+               c_write_str(ssh, "\r\n");
            }
+           sfree(userlog);
        }
     }
 
     crWaitUntil(pktin);
 
-    if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
+    if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
        /* We must not attempt PK auth. Pretend we've already tried it. */
        s->tried_publickey = s->tried_agent = 1;
     } else {
        s->tried_publickey = s->tried_agent = 0;
     }
     s->tis_auth_refused = s->ccard_auth_refused = 0;
-    /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
+    /*
+     * Load the public half of any configured keyfile for later use.
+     */
     if (!filename_is_null(ssh->cfg.keyfile)) {
-       if (!rsakey_pubblob(&ssh->cfg.keyfile,
-                           &s->publickey_blob, &s->publickey_bloblen, NULL))
+       int keytype;
+       logeventf(ssh, "Reading private key file \"%.150s\"",
+                 filename_to_str(&ssh->cfg.keyfile));
+       keytype = key_type(&ssh->cfg.keyfile);
+       if (keytype == SSH_KEYTYPE_SSH1) {
+           const char *error;
+           if (rsakey_pubblob(&ssh->cfg.keyfile,
+                              &s->publickey_blob, &s->publickey_bloblen,
+                              &s->publickey_comment, &error)) {
+               s->publickey_encrypted = rsakey_encrypted(&ssh->cfg.keyfile,
+                                                         NULL);
+           } else {
+               char *msgbuf;
+               logeventf(ssh, "Unable to load private key (%s)", error);
+               msgbuf = dupprintf("Unable to load private key file "
+                                  "\"%.150s\" (%s)\r\n",
+                                  filename_to_str(&ssh->cfg.keyfile),
+                                  error);
+               c_write_str(ssh, msgbuf);
+               sfree(msgbuf);
+               s->publickey_blob = NULL;
+           }
+       } else {
+           char *msgbuf;
+           logeventf(ssh, "Unable to use this key file (%s)",
+                     key_type_to_str(keytype));
+           msgbuf = dupprintf("Unable to use key file \"%.150s\""
+                              " (%s)\r\n",
+                              filename_to_str(&ssh->cfg.keyfile),
+                              key_type_to_str(keytype));
+           c_write_str(ssh, msgbuf);
+           sfree(msgbuf);
            s->publickey_blob = NULL;
+       }
     } else
        s->publickey_blob = NULL;
 
     while (pktin->type == SSH1_SMSG_FAILURE) {
        s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
 
-       if (agent_exists() && !s->tried_agent) {
+       if (ssh->cfg.tryagent && agent_exists() && !s->tried_agent) {
            /*
             * Attempt RSA authentication using Pageant.
             */
@@ -3298,13 +3589,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
                s->p += 4;
                logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
                for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
-                   logeventf(ssh, "Trying Pageant key #%d", s->keyi);
-                   if (s->publickey_blob &&
-                       !memcmp(s->p, s->publickey_blob,
-                               s->publickey_bloblen)) {
-                       logevent("This key matches configured key file");
-                       s->tried_publickey = 1;
-                   }
+                   unsigned char *pkblob = s->p;
                    s->p += 4;
                    {
                        int n, ok = FALSE;
@@ -3337,6 +3622,17 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
                            break;
                        }
                    }
+                   if (s->publickey_blob) {
+                       if (!memcmp(pkblob, s->publickey_blob,
+                                   s->publickey_bloblen)) {
+                           logeventf(ssh, "Pageant key #%d matches "
+                                     "configured key file", s->keyi);
+                           s->tried_publickey = 1;
+                       } else
+                           /* Skip non-configured key */
+                           continue;
+                   }
+                   logeventf(ssh, "Trying Pageant key #%d", s->keyi);
                    send_packet(ssh, SSH1_CMSG_AUTH_RSA,
                                PKT_BIGNUM, s->key.modulus, PKT_END);
                    crWaitUntil(pktin);
@@ -3427,12 +3723,156 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
                        break;
                }
                sfree(s->response);
+               if (s->publickey_blob && !s->tried_publickey)
+                   logevent("Configured key file not in Pageant");
            }
            if (s->authed)
                break;
        }
-       if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
-           s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
+       if (s->publickey_blob && !s->tried_publickey) {
+           /*
+            * Try public key authentication with the specified
+            * key file.
+            */
+           int got_passphrase; /* need not be kept over crReturn */
+           if (flags & FLAG_VERBOSE)
+               c_write_str(ssh, "Trying public key authentication.\r\n");
+           logeventf(ssh, "Trying public key \"%s\"",
+                     filename_to_str(&ssh->cfg.keyfile));
+           s->tried_publickey = 1;
+           got_passphrase = FALSE;
+           while (!got_passphrase) {
+               /*
+                * Get a passphrase, if necessary.
+                */
+               char *passphrase = NULL;    /* only written after crReturn */
+               const char *error;
+               if (!s->publickey_encrypted) {
+                   if (flags & FLAG_VERBOSE)
+                       c_write_str(ssh, "No passphrase required.\r\n");
+                   passphrase = NULL;
+               } else {
+                   int ret; /* need not be kept over crReturn */
+                   s->cur_prompt = new_prompts(ssh->frontend);
+                   s->cur_prompt->to_server = FALSE;
+                   s->cur_prompt->name = dupstr("SSH key passphrase");
+                   add_prompt(s->cur_prompt,
+                              dupprintf("Passphrase for key \"%.100s\": ",
+                                        s->publickey_comment),
+                              FALSE, SSH_MAX_PASSWORD_LEN);
+                   ret = get_userpass_input(s->cur_prompt, NULL, 0);
+                   while (ret < 0) {
+                       ssh->send_ok = 1;
+                       crWaitUntil(!pktin);
+                       ret = get_userpass_input(s->cur_prompt, in, inlen);
+                       ssh->send_ok = 0;
+                   }
+                   if (!ret) {
+                       /* Failed to get a passphrase. Terminate. */
+                       free_prompts(s->cur_prompt);
+                       ssh_disconnect(ssh, NULL, "Unable to authenticate",
+                                      0, TRUE);
+                       crStop(0);
+                   }
+                   passphrase = dupstr(s->cur_prompt->prompts[0]->result);
+                   free_prompts(s->cur_prompt);
+               }
+               /*
+                * Try decrypting key with passphrase.
+                */
+               ret = loadrsakey(&ssh->cfg.keyfile, &s->key, passphrase,
+                                &error);
+               if (passphrase) {
+                   memset(passphrase, 0, strlen(passphrase));
+                   sfree(passphrase);
+               }
+               if (ret == 1) {
+                   /* Correct passphrase. */
+                   got_passphrase = TRUE;
+               } else if (ret == 0) {
+                   c_write_str(ssh, "Couldn't load private key from ");
+                   c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
+                   c_write_str(ssh, " (");
+                   c_write_str(ssh, error);
+                   c_write_str(ssh, ").\r\n");
+                   got_passphrase = FALSE;
+                   break;             /* go and try something else */
+               } else if (ret == -1) {
+                   c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
+                   got_passphrase = FALSE;
+                   /* and try again */
+               } else {
+                   assert(0 && "unexpected return from loadrsakey()");
+                   got_passphrase = FALSE;   /* placate optimisers */
+               }
+           }
+
+           if (got_passphrase) {
+
+               /*
+                * Send a public key attempt.
+                */
+               send_packet(ssh, SSH1_CMSG_AUTH_RSA,
+                           PKT_BIGNUM, s->key.modulus, PKT_END);
+
+               crWaitUntil(pktin);
+               if (pktin->type == SSH1_SMSG_FAILURE) {
+                   c_write_str(ssh, "Server refused our public key.\r\n");
+                   continue;          /* go and try something else */
+               }
+               if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
+                   bombout(("Bizarre response to offer of public key"));
+                   crStop(0);
+               }
+
+               {
+                   int i;
+                   unsigned char buffer[32];
+                   Bignum challenge, response;
+
+                   if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
+                       bombout(("Server's RSA challenge was badly formatted"));
+                       crStop(0);
+                   }
+                   response = rsadecrypt(challenge, &s->key);
+                   freebn(s->key.private_exponent);/* burn the evidence */
+
+                   for (i = 0; i < 32; i++) {
+                       buffer[i] = bignum_byte(response, 31 - i);
+                   }
+
+                   MD5Init(&md5c);
+                   MD5Update(&md5c, buffer, 32);
+                   MD5Update(&md5c, s->session_id, 16);
+                   MD5Final(buffer, &md5c);
+
+                   send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
+                               PKT_DATA, buffer, 16, PKT_END);
+
+                   freebn(challenge);
+                   freebn(response);
+               }
+
+               crWaitUntil(pktin);
+               if (pktin->type == SSH1_SMSG_FAILURE) {
+                   if (flags & FLAG_VERBOSE)
+                       c_write_str(ssh, "Failed to authenticate with"
+                                   " our public key.\r\n");
+                   continue;          /* go and try something else */
+               } else if (pktin->type != SSH1_SMSG_SUCCESS) {
+                   bombout(("Bizarre response to RSA authentication response"));
+                   crStop(0);
+               }
+
+               break;                 /* we're through! */
+           }
+
+       }
+
+       /*
+        * Otherwise, try various forms of password-like authentication.
+        */
+       s->cur_prompt = new_prompts(ssh->frontend);
 
        if (ssh->cfg.try_tis_auth &&
            (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
@@ -3450,23 +3890,31 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
            } else {
                char *challenge;
                int challengelen;
+               char *instr_suf, *prompt;
 
                ssh_pkt_getstring(pktin, &challenge, &challengelen);
                if (!challenge) {
                    bombout(("TIS challenge packet was badly formed"));
                    crStop(0);
                }
-               c_write_str(ssh, "Using TIS authentication.\r\n");
                logevent("Received TIS challenge");
-               if (challengelen > sizeof(s->prompt) - 1)
-                   challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
-               memcpy(s->prompt, challenge, challengelen);
+               s->cur_prompt->to_server = TRUE;
+               s->cur_prompt->name = dupstr("SSH TIS authentication");
                /* Prompt heuristic comes from OpenSSH */
-               strncpy(s->prompt + challengelen,
-                       memchr(s->prompt, '\n', challengelen) ?
-                       "": "\r\nResponse: ",
-                       (sizeof s->prompt) - challengelen);
-               s->prompt[(sizeof s->prompt) - 1] = '\0';
+               if (memchr(challenge, '\n', challengelen)) {
+                   instr_suf = dupstr("");
+                   prompt = dupprintf("%.*s", challengelen, challenge);
+               } else {
+                   instr_suf = dupprintf("%.*s", challengelen, challenge);
+                   prompt = dupstr("Response: ");
+               }
+               s->cur_prompt->instruction =
+                   dupprintf("Using TIS authentication.%s%s",
+                             (*instr_suf) ? "\n" : "",
+                             instr_suf);
+               s->cur_prompt->instr_reqd = TRUE;
+               add_prompt(s->cur_prompt, prompt, FALSE, SSH_MAX_PASSWORD_LEN);
+               sfree(instr_suf);
            }
        }
        if (ssh->cfg.try_tis_auth &&
@@ -3484,53 +3932,44 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
            } else {
                char *challenge;
                int challengelen;
+               char *instr_suf, *prompt;
 
                ssh_pkt_getstring(pktin, &challenge, &challengelen);
                if (!challenge) {
                    bombout(("CryptoCard challenge packet was badly formed"));
                    crStop(0);
                }
-               c_write_str(ssh, "Using CryptoCard authentication.\r\n");
                logevent("Received CryptoCard challenge");
-               if (challengelen > sizeof(s->prompt) - 1)
-                   challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
-               memcpy(s->prompt, challenge, challengelen);
-               strncpy(s->prompt + challengelen,
-                       memchr(s->prompt, '\n', challengelen) ?
-                       "" : "\r\nResponse: ",
-                       sizeof(s->prompt) - challengelen);
-               s->prompt[sizeof(s->prompt) - 1] = '\0';
+               s->cur_prompt->to_server = TRUE;
+               s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
+               s->cur_prompt->name_reqd = FALSE;
+               /* Prompt heuristic comes from OpenSSH */
+               if (memchr(challenge, '\n', challengelen)) {
+                   instr_suf = dupstr("");
+                   prompt = dupprintf("%.*s", challengelen, challenge);
+               } else {
+                   instr_suf = dupprintf("%.*s", challengelen, challenge);
+                   prompt = dupstr("Response: ");
+               }
+               s->cur_prompt->instruction =
+                   dupprintf("Using CryptoCard authentication.%s%s",
+                             (*instr_suf) ? "\n" : "",
+                             instr_suf);
+               s->cur_prompt->instr_reqd = TRUE;
+               add_prompt(s->cur_prompt, prompt, FALSE, SSH_MAX_PASSWORD_LEN);
+               sfree(instr_suf);
            }
        }
        if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
-           sprintf(s->prompt, "%.90s@%.90s's password: ",
-                   s->username, ssh->savedhost);
-       }
-       if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
-           char *comment = NULL;
-           int type;
-           if (flags & FLAG_VERBOSE)
-               c_write_str(ssh, "Trying public key authentication.\r\n");
-           logeventf(ssh, "Trying public key \"%s\"",
-                     filename_to_str(&ssh->cfg.keyfile));
-           type = key_type(&ssh->cfg.keyfile);
-           if (type != SSH_KEYTYPE_SSH1) {
-               char *msg = dupprintf("Key is of wrong type (%s)",
-                                     key_type_to_str(type));
-               logevent(msg);
-               c_write_str(ssh, msg);
-               c_write_str(ssh, "\r\n");
-               sfree(msg);
-               s->tried_publickey = 1;
-               continue;
-           }
-           if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
-               if (flags & FLAG_VERBOSE)
-                   c_write_str(ssh, "No passphrase required.\r\n");
-               goto tryauth;
+           if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
+               bombout(("No supported authentication methods available"));
+               crStop(0);
            }
-           sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
-           sfree(comment);
+           s->cur_prompt->to_server = TRUE;
+           s->cur_prompt->name = dupstr("SSH password");
+           add_prompt(s->cur_prompt, dupprintf("%.90s@%.90s's password: ",
+                                               s->username, ssh->savedhost),
+                      FALSE, SSH_MAX_PASSWORD_LEN);
        }
 
        /*
@@ -3538,245 +3977,153 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
         * or CryptoCard exchange if we're doing TIS or CryptoCard
         * authentication.
         */
-       if (ssh_get_line) {
-           if (!ssh_get_line(s->prompt, s->password,
-                             sizeof(s->password), TRUE)) {
+       {
+           int ret; /* need not be kept over crReturn */
+           ret = get_userpass_input(s->cur_prompt, NULL, 0);
+           while (ret < 0) {
+               ssh->send_ok = 1;
+               crWaitUntil(!pktin);
+               ret = get_userpass_input(s->cur_prompt, in, inlen);
+               ssh->send_ok = 0;
+           }
+           if (!ret) {
                /*
-                * get_line failed to get a password (for example
+                * Failed to get a password (for example
                 * because one was supplied on the command line
                 * which has already failed to work). Terminate.
                 */
-               ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, FALSE);
-               crStop(1);
+               free_prompts(s->cur_prompt);
+               ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
+               crStop(0);
            }
-       } else {
-           /* Prompt may have come from server. We've munged it a bit, so
-            * we know it to be zero-terminated at least once. */
-           int ret;                   /* need not be saved over crReturn */
-           c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
-           s->pos = 0;
-
-           setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
-           do {
-               crWaitUntil(!pktin);
-               ret = process_userpass_input(ssh, in, inlen);
-           } while (ret == 0);
-           if (ret < 0)
-               cleanup_exit(0);
-           c_write_str(ssh, "\r\n");
        }
 
-      tryauth:
-       if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
-           /*
-            * Try public key authentication with the specified
-            * key file.
-            */
-           s->tried_publickey = 1;
-           
-           {
-               const char *error = NULL;
-               int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
-                                    &error);
-               if (ret == 0) {
-                   c_write_str(ssh, "Couldn't load private key from ");
-                   c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
-                   c_write_str(ssh, " (");
-                   c_write_str(ssh, error);
-                   c_write_str(ssh, ").\r\n");
-                   continue;          /* go and try password */
-               }
-               if (ret == -1) {
-                   c_write_str(ssh, "Wrong passphrase.\r\n");
-                   s->tried_publickey = 0;
-                   continue;          /* try again */
-               }
-           }
-
+       if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
            /*
-            * Send a public key attempt.
+            * Defence against traffic analysis: we send a
+            * whole bunch of packets containing strings of
+            * different lengths. One of these strings is the
+            * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
+            * The others are all random data in
+            * SSH1_MSG_IGNORE packets. This way a passive
+            * listener can't tell which is the password, and
+            * hence can't deduce the password length.
+            * 
+            * Anybody with a password length greater than 16
+            * bytes is going to have enough entropy in their
+            * password that a listener won't find it _that_
+            * much help to know how long it is. So what we'll
+            * do is:
+            * 
+            *  - if password length < 16, we send 15 packets
+            *    containing string lengths 1 through 15
+            * 
+            *  - otherwise, we let N be the nearest multiple
+            *    of 8 below the password length, and send 8
+            *    packets containing string lengths N through
+            *    N+7. This won't obscure the order of
+            *    magnitude of the password length, but it will
+            *    introduce a bit of extra uncertainty.
+            * 
+            * A few servers can't deal with SSH1_MSG_IGNORE, at
+            * least in this context. For these servers, we need
+            * an alternative defence. We make use of the fact
+            * that the password is interpreted as a C string:
+            * so we can append a NUL, then some random data.
+            * 
+            * A few servers can deal with neither SSH1_MSG_IGNORE
+            * here _nor_ a padded password string.
+            * For these servers we are left with no defences
+            * against password length sniffing.
             */
-           send_packet(ssh, SSH1_CMSG_AUTH_RSA,
-                       PKT_BIGNUM, s->key.modulus, PKT_END);
-
-           crWaitUntil(pktin);
-           if (pktin->type == SSH1_SMSG_FAILURE) {
-               c_write_str(ssh, "Server refused our public key.\r\n");
-               continue;              /* go and try password */
-           }
-           if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
-               bombout(("Bizarre response to offer of public key"));
-               crStop(0);
-           }
-
-           {
-               int i;
-               unsigned char buffer[32];
-               Bignum challenge, response;
-
-               if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
-                   bombout(("Server's RSA challenge was badly formatted"));
-                   crStop(0);
-               }
-               response = rsadecrypt(challenge, &s->key);
-               freebn(s->key.private_exponent);/* burn the evidence */
-
-               for (i = 0; i < 32; i++) {
-                   buffer[i] = bignum_byte(response, 31 - i);
-               }
-
-               MD5Init(&md5c);
-               MD5Update(&md5c, buffer, 32);
-               MD5Update(&md5c, s->session_id, 16);
-               MD5Final(buffer, &md5c);
-
-               send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
-                           PKT_DATA, buffer, 16, PKT_END);
-
-               freebn(challenge);
-               freebn(response);
-           }
-
-           crWaitUntil(pktin);
-           if (pktin->type == SSH1_SMSG_FAILURE) {
-               if (flags & FLAG_VERBOSE)
-                   c_write_str(ssh, "Failed to authenticate with"
-                               " our public key.\r\n");
-               continue;              /* go and try password */
-           } else if (pktin->type != SSH1_SMSG_SUCCESS) {
-               bombout(("Bizarre response to RSA authentication response"));
-               crStop(0);
-           }
-
-           break;                     /* we're through! */
-       } else {
-           if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
+           if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
+               !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
                /*
-                * Defence against traffic analysis: we send a
-                * whole bunch of packets containing strings of
-                * different lengths. One of these strings is the
-                * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
-                * The others are all random data in
-                * SSH1_MSG_IGNORE packets. This way a passive
-                * listener can't tell which is the password, and
-                * hence can't deduce the password length.
-                * 
-                * Anybody with a password length greater than 16
-                * bytes is going to have enough entropy in their
-                * password that a listener won't find it _that_
-                * much help to know how long it is. So what we'll
-                * do is:
-                * 
-                *  - if password length < 16, we send 15 packets
-                *    containing string lengths 1 through 15
-                * 
-                *  - otherwise, we let N be the nearest multiple
-                *    of 8 below the password length, and send 8
-                *    packets containing string lengths N through
-                *    N+7. This won't obscure the order of
-                *    magnitude of the password length, but it will
-                *    introduce a bit of extra uncertainty.
-                * 
-                * A few servers (the old 1.2.18 through 1.2.22)
-                * can't deal with SSH1_MSG_IGNORE. For these
-                * servers, we need an alternative defence. We make
-                * use of the fact that the password is interpreted
-                * as a C string: so we can append a NUL, then some
-                * random data.
-                * 
-                * One server (a Cisco one) can deal with neither
-                * SSH1_MSG_IGNORE _nor_ a padded password string.
-                * For this server we are left with no defences
-                * against password length sniffing.
+                * The server can deal with SSH1_MSG_IGNORE, so
+                * we can use the primary defence.
                 */
-               if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
-                   /*
-                    * The server can deal with SSH1_MSG_IGNORE, so
-                    * we can use the primary defence.
-                    */
-                   int bottom, top, pwlen, i;
-                   char *randomstr;
+               int bottom, top, pwlen, i;
+               char *randomstr;
 
-                   pwlen = strlen(s->password);
-                   if (pwlen < 16) {
-                       bottom = 0;    /* zero length passwords are OK! :-) */
-                       top = 15;
-                   } else {
-                       bottom = pwlen & ~7;
-                       top = bottom + 7;
-                   }
+               pwlen = strlen(s->cur_prompt->prompts[0]->result);
+               if (pwlen < 16) {
+                   bottom = 0;    /* zero length passwords are OK! :-) */
+                   top = 15;
+               } else {
+                   bottom = pwlen & ~7;
+                   top = bottom + 7;
+               }
 
-                   assert(pwlen >= bottom && pwlen <= top);
+               assert(pwlen >= bottom && pwlen <= top);
 
-                   randomstr = snewn(top + 1, char);
+               randomstr = snewn(top + 1, char);
 
-                   for (i = bottom; i <= top; i++) {
-                       if (i == pwlen) {
-                           defer_packet(ssh, s->pwpkt_type,
-                                        PKTT_PASSWORD, PKT_STR, s->password,
-                                        PKTT_OTHER, PKT_END);
-                       } else {
-                           for (j = 0; j < i; j++) {
-                               do {
-                                   randomstr[j] = random_byte();
-                               } while (randomstr[j] == '\0');
-                           }
-                           randomstr[i] = '\0';
-                           defer_packet(ssh, SSH1_MSG_IGNORE,
-                                        PKT_STR, randomstr, PKT_END);
+               for (i = bottom; i <= top; i++) {
+                   if (i == pwlen) {
+                       defer_packet(ssh, s->pwpkt_type,
+                                    PKTT_PASSWORD, PKT_STR,
+                                    s->cur_prompt->prompts[0]->result,
+                                    PKTT_OTHER, PKT_END);
+                   } else {
+                       for (j = 0; j < i; j++) {
+                           do {
+                               randomstr[j] = random_byte();
+                           } while (randomstr[j] == '\0');
                        }
+                       randomstr[i] = '\0';
+                       defer_packet(ssh, SSH1_MSG_IGNORE,
+                                    PKT_STR, randomstr, PKT_END);
                    }
-                   logevent("Sending password with camouflage packets");
-                   ssh_pkt_defersend(ssh);
-                   sfree(randomstr);
-               } 
-               else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
-                   /*
-                    * The server can't deal with SSH1_MSG_IGNORE
-                    * but can deal with padded passwords, so we
-                    * can use the secondary defence.
-                    */
-                   char string[64];
-                   char *ss;
-                   int len;
-
-                   len = strlen(s->password);
-                   if (len < sizeof(string)) {
-                       ss = string;
-                       strcpy(string, s->password);
-                       len++;         /* cover the zero byte */
-                       while (len < sizeof(string)) {
-                           string[len++] = (char) random_byte();
-                       }
-                   } else {
-                       ss = s->password;
+               }
+               logevent("Sending password with camouflage packets");
+               ssh_pkt_defersend(ssh);
+               sfree(randomstr);
+           } 
+           else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
+               /*
+                * The server can't deal with SSH1_MSG_IGNORE
+                * but can deal with padded passwords, so we
+                * can use the secondary defence.
+                */
+               char string[64];
+               char *ss;
+               int len;
+
+               len = strlen(s->cur_prompt->prompts[0]->result);
+               if (len < sizeof(string)) {
+                   ss = string;
+                   strcpy(string, s->cur_prompt->prompts[0]->result);
+                   len++;             /* cover the zero byte */
+                   while (len < sizeof(string)) {
+                       string[len++] = (char) random_byte();
                    }
-                   logevent("Sending length-padded password");
-                   send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
-                               PKT_INT, len, PKT_DATA, ss, len,
-                               PKTT_OTHER, PKT_END);
                } else {
-                   /*
-                    * The server has _both_
-                    * BUG_CHOKES_ON_SSH1_IGNORE and
-                    * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
-                    * therefore nothing we can do.
-                    */
-                   int len;
-                   len = strlen(s->password);
-                   logevent("Sending unpadded password");
-                   send_packet(ssh, s->pwpkt_type,
-                               PKTT_PASSWORD, PKT_INT, len,
-                               PKT_DATA, s->password, len,
-                               PKTT_OTHER, PKT_END);
+                   ss = s->cur_prompt->prompts[0]->result;
                }
-           } else {
+               logevent("Sending length-padded password");
                send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
-                           PKT_STR, s->password, PKTT_OTHER, PKT_END);
+                           PKT_INT, len, PKT_DATA, ss, len,
+                           PKTT_OTHER, PKT_END);
+           } else {
+               /*
+                * The server is believed unable to cope with
+                * any of our password camouflage methods.
+                */
+               int len;
+               len = strlen(s->cur_prompt->prompts[0]->result);
+               logevent("Sending unpadded password");
+               send_packet(ssh, s->pwpkt_type,
+                           PKTT_PASSWORD, PKT_INT, len,
+                           PKT_DATA, s->cur_prompt->prompts[0]->result, len,
+                           PKTT_OTHER, PKT_END);
            }
+       } else {
+           send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
+                       PKT_STR, s->cur_prompt->prompts[0]->result,
+                       PKTT_OTHER, PKT_END);
        }
        logevent("Sent password");
-       memset(s->password, 0, strlen(s->password));
+       free_prompts(s->cur_prompt);
        crWaitUntil(pktin);
        if (pktin->type == SSH1_SMSG_FAILURE) {
            if (flags & FLAG_VERBOSE)
@@ -3788,6 +4135,12 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
        }
     }
 
+    /* Clear up */
+    if (s->publickey_blob) {
+       sfree(s->publickey_blob);
+       sfree(s->publickey_comment);
+    }
+
     logevent("Authentication successful");
 
     crFinish(1);
@@ -3841,8 +4194,7 @@ int sshfwd_write(struct ssh_channel *c, char *buf, int len)
     if (ssh->version == 1) {
        send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
                    PKT_INT, c->remoteid,
-                   PKTT_DATA,
-                   PKT_INT, len, PKT_DATA, buf, len,
+                   PKT_INT, len, PKTT_DATA, PKT_DATA, buf, len,
                    PKTT_OTHER, PKT_END);
        /*
         * In SSH-1 we can return 0 here - implying that forwarded
@@ -3861,17 +4213,20 @@ int sshfwd_write(struct ssh_channel *c, char *buf, int len)
 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
 {
     Ssh ssh = c->ssh;
+    int buflimit;
 
     if (ssh->state == SSH_STATE_CLOSED)
        return;
 
     if (ssh->version == 1) {
-       if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
-           c->v.v1.throttling = 0;
-           ssh1_throttle(ssh, -1);
-       }
+       buflimit = SSH1_BUFFER_LIMIT;
     } else {
-       ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
+       buflimit = c->v.v2.locmaxwin;
+       ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
+    }
+    if (c->throttling_conn && bufsize <= buflimit) {
+       c->throttling_conn = 0;
+       ssh_throttle_conn(ssh, -1);
     }
 }
 
@@ -4087,12 +4442,19 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
 
            epfrec = add234(ssh->portfwds, pfrec);
            if (epfrec != pfrec) {
+               if (epfrec->status == DESTROY) {
+                   /*
+                    * We already have a port forwarding up and running
+                    * with precisely these parameters. Hence, no need
+                    * to do anything; simply re-tag the existing one
+                    * as KEEP.
+                    */
+                   epfrec->status = KEEP;
+               }
                /*
-                * We already have a port forwarding with precisely
-                * these parameters. Hence, no need to do anything;
-                * simply tag the existing one as KEEP.
+                * Anything else indicates that there was a duplicate
+                * in our input, which we'll silently ignore.
                 */
-               epfrec->status = KEEP;
                free_portfwd(pfrec);
            } else {
                pfrec->status = CREATE;
@@ -4300,7 +4662,7 @@ static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
                           string, stringlen);
     if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
        ssh->v1_stdout_throttling = 1;
-       ssh1_throttle(ssh, +1);
+       ssh_throttle_conn(ssh, +1);
     }
 }
 
@@ -4321,8 +4683,8 @@ static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
        c = snew(struct ssh_channel);
        c->ssh = ssh;
 
-       if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
-                    ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
+       if (x11_init(&c->u.x11.s, ssh->x11disp, c,
+                    NULL, -1, &ssh->cfg) != NULL) {
            logevent("Opening X11 forward connection failed");
            sfree(c);
            send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
@@ -4334,7 +4696,7 @@ static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
            c->halfopen = FALSE;
            c->localid = alloc_channel_id(ssh);
            c->closes = 0;
-           c->v.v1.throttling = 0;
+           c->throttling_conn = 0;
            c->type = CHAN_X11; /* identify channel type */
            add234(ssh->channels, c);
            send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
@@ -4363,7 +4725,7 @@ static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
        c->halfopen = FALSE;
        c->localid = alloc_channel_id(ssh);
        c->closes = 0;
-       c->v.v1.throttling = 0;
+       c->throttling_conn = 0;
        c->type = CHAN_AGENT;   /* identify channel type */
        c->u.a.lensofar = 0;
        add234(ssh->channels, c);
@@ -4417,7 +4779,7 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
            c->halfopen = FALSE;
            c->localid = alloc_channel_id(ssh);
            c->closes = 0;
-           c->v.v1.throttling = 0;
+           c->throttling_conn = 0;
            c->type = CHAN_SOCKDATA;    /* identify channel type */
            add234(ssh->channels, c);
            send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
@@ -4439,7 +4801,7 @@ static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
        c->remoteid = localid;
        c->halfopen = FALSE;
        c->type = CHAN_SOCKDATA;
-       c->v.v1.throttling = 0;
+       c->throttling_conn = 0;
        pfd_confirm(c->u.pfd.s);
     }
 
@@ -4536,7 +4898,7 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
            /* Data for an agent message. Buffer it. */
            while (len > 0) {
                if (c->u.a.lensofar < 4) {
-                   unsigned int l = min(4 - c->u.a.lensofar, len);
+                   unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
                    memcpy(c->u.a.msglen + c->u.a.lensofar, p,
                           l);
                    p += l;
@@ -4553,7 +4915,7 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
                if (c->u.a.lensofar >= 4 && len > 0) {
                    unsigned int l =
                        min(c->u.a.totallen - c->u.a.lensofar,
-                           len);
+                           (unsigned)len);
                    memcpy(c->u.a.message + c->u.a.lensofar, p,
                           l);
                    p += l;
@@ -4575,9 +4937,9 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
            bufsize = 0;   /* agent channels never back up */
            break;
        }
-       if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
-           c->v.v1.throttling = 1;
-           ssh1_throttle(ssh, +1);
+       if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
+           c->throttling_conn = 1;
+           ssh_throttle_conn(ssh, +1);
        }
     }
 }
@@ -4656,12 +5018,10 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
        }
     }
 
-    if (ssh->cfg.x11_forward) {
-       char proto[20], data[64];
+    if (ssh->cfg.x11_forward &&
+       (ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                         ssh->cfg.x11_auth, &ssh->cfg))) {
        logevent("Requesting X11 forwarding");
-       ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
-                                      data, sizeof(data), ssh->cfg.x11_auth);
-        x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
        /*
         * Note that while we blank the X authentication data here, we don't
         * take any special action to blank the start of an X11 channel,
@@ -4671,14 +5031,19 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
         */
        if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
            send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
-                       PKT_STR, proto,
-                       PKTT_PASSWORD, PKT_STR, data, PKTT_OTHER,
-                       PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
+                       PKT_STR, ssh->x11disp->remoteauthprotoname,
+                       PKTT_PASSWORD,
+                       PKT_STR, ssh->x11disp->remoteauthdatastring,
+                       PKTT_OTHER,
+                       PKT_INT, ssh->x11disp->screennum,
                        PKT_END);
        } else {
            send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
-                       PKT_STR, proto,
-                       PKTT_PASSWORD, PKT_STR, data, PKTT_OTHER, PKT_END);
+                       PKT_STR, ssh->x11disp->remoteauthprotoname,
+                       PKTT_PASSWORD,
+                       PKT_STR, ssh->x11disp->remoteauthdatastring,
+                       PKTT_OTHER,
+                       PKT_END);
        }
        do {
            crReturnV;
@@ -4813,8 +5178,8 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
        } else {
            while (inlen > 0) {
                int len = min(inlen, 512);
-               send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA,
-                           PKT_INT, len, PKT_DATA, in, len,
+               send_packet(ssh, SSH1_CMSG_STDIN_DATA,
+                           PKT_INT, len,  PKTT_DATA, PKT_DATA, in, len,
                            PKTT_OTHER, PKT_END);
                in += len;
                inlen -= len;
@@ -4947,7 +5312,10 @@ static int first_in_commasep_string(char *needle, char *haystack, int haylen)
 
 /*
  * SSH-2 key creation method.
+ * (Currently assumes 2 lots of any hash are sufficient to generate
+ * keys/IVs for any cipher/MAC. SSH2_MKKEY_ITERS documents this assumption.)
  */
+#define SSH2_MKKEY_ITERS (2)
 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, char chr,
                       unsigned char *keyspace)
 {
@@ -4991,10 +5359,11 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
        const struct ssh_mac *scmac_tobe;
        const struct ssh_compress *cscomp_tobe;
        const struct ssh_compress *sccomp_tobe;
-       char *hostkeydata, *sigdata, *keystr, *fingerprint;
-       int hostkeylen, siglen;
+       char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
+       int hostkeylen, siglen, rsakeylen;
        void *hkey;                    /* actual host key */
-       unsigned char exchange_hash[20];
+       void *rsakey;                  /* for RSA kex */
+       unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
        int n_preferred_kex;
        const struct ssh_kexes *preferred_kex[KEX_MAX];
        int n_preferred_ciphers;
@@ -5025,7 +5394,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
        s->maclist = macs, s->nmacs = lenof(macs);
 
   begin_key_exchange:
-    ssh->pkt_ctx &= ~SSH2_PKTCTX_KEX_MASK;
+    ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
     {
        int i, j, commalist_started;
 
@@ -5047,7 +5416,11 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
                s->preferred_kex[s->n_preferred_kex++] =
                    &ssh_diffiehellman_group1;
                break;
-             case CIPHER_WARN:
+             case KEX_RSA:
+               s->preferred_kex[s->n_preferred_kex++] =
+                   &ssh_rsa_kex;
+               break;
+             case KEX_WARN:
                /* Flag for later. Don't bother if it's the last in
                 * the list. */
                if (i < KEX_MAX - 1) {
@@ -5446,106 +5819,217 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
            crWaitUntil(pktin);                /* Ignore packet */
     }
 
-    /*
-     * Work out the number of bits of key we will need from the key
-     * exchange. We start with the maximum key length of either
-     * cipher...
-     */
-    {
-       int csbits, scbits;
+    if (ssh->kex->main_type == KEXTYPE_DH) {
+        /*
+         * Work out the number of bits of key we will need from the
+         * key exchange. We start with the maximum key length of
+         * either cipher...
+         */
+        {
+            int csbits, scbits;
 
-       csbits = s->cscipher_tobe->keylen;
-       scbits = s->sccipher_tobe->keylen;
-       s->nbits = (csbits > scbits ? csbits : scbits);
-    }
-    /* The keys only have hlen-bit entropy, since they're based on
-     * a hash. So cap the key size at hlen bits. */
-    if (s->nbits > ssh->kex->hash->hlen * 8)
-       s->nbits = ssh->kex->hash->hlen * 8;
+            csbits = s->cscipher_tobe->keylen;
+            scbits = s->sccipher_tobe->keylen;
+            s->nbits = (csbits > scbits ? csbits : scbits);
+        }
+        /* The keys only have hlen-bit entropy, since they're based on
+         * a hash. So cap the key size at hlen bits. */
+        if (s->nbits > ssh->kex->hash->hlen * 8)
+            s->nbits = ssh->kex->hash->hlen * 8;
 
-    /*
-     * If we're doing Diffie-Hellman group exchange, start by
-     * requesting a group.
-     */
-    if (!ssh->kex->pdata) {
-       logevent("Doing Diffie-Hellman group exchange");
-       ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
-       /*
-        * Work out how big a DH group we will need to allow that
-        * much data.
-        */
-       s->pbits = 512 << ((s->nbits - 1) / 64);
-       s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
-       ssh2_pkt_adduint32(s->pktout, s->pbits);
-       ssh2_pkt_send_noqueue(ssh, s->pktout);
+        /*
+         * If we're doing Diffie-Hellman group exchange, start by
+         * requesting a group.
+         */
+        if (!ssh->kex->pdata) {
+            logevent("Doing Diffie-Hellman group exchange");
+            ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
+            /*
+             * Work out how big a DH group we will need to allow that
+             * much data.
+             */
+            s->pbits = 512 << ((s->nbits - 1) / 64);
+            s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
+            ssh2_pkt_adduint32(s->pktout, s->pbits);
+            ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+            crWaitUntil(pktin);
+            if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
+                bombout(("expected key exchange group packet from server"));
+                crStop(0);
+            }
+            s->p = ssh2_pkt_getmp(pktin);
+            s->g = ssh2_pkt_getmp(pktin);
+            if (!s->p || !s->g) {
+                bombout(("unable to read mp-ints from incoming group packet"));
+                crStop(0);
+            }
+            ssh->kex_ctx = dh_setup_gex(s->p, s->g);
+            s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
+            s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
+        } else {
+            ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
+            ssh->kex_ctx = dh_setup_group(ssh->kex);
+            s->kex_init_value = SSH2_MSG_KEXDH_INIT;
+            s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
+            logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
+                      ssh->kex->groupname);
+        }
 
-       crWaitUntil(pktin);
-       if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
-           bombout(("expected key exchange group packet from server"));
-           crStop(0);
-       }
-       s->p = ssh2_pkt_getmp(pktin);
-       s->g = ssh2_pkt_getmp(pktin);
-       if (!s->p || !s->g) {
-           bombout(("unable to read mp-ints from incoming group packet"));
-           crStop(0);
-       }
-       ssh->kex_ctx = dh_setup_gex(s->p, s->g);
-       s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
-       s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
+        logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
+                  ssh->kex->hash->text_name);
+        /*
+         * Now generate and send e for Diffie-Hellman.
+         */
+        set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
+        s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
+        s->pktout = ssh2_pkt_init(s->kex_init_value);
+        ssh2_pkt_addmp(s->pktout, s->e);
+        ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+        set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
+        crWaitUntil(pktin);
+        if (pktin->type != s->kex_reply_value) {
+            bombout(("expected key exchange reply packet from server"));
+            crStop(0);
+        }
+        set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
+        ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
+        s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
+        s->f = ssh2_pkt_getmp(pktin);
+        if (!s->f) {
+            bombout(("unable to parse key exchange reply packet"));
+            crStop(0);
+        }
+        ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
+
+        s->K = dh_find_K(ssh->kex_ctx, s->f);
+
+        /* We assume everything from now on will be quick, and it might
+         * involve user interaction. */
+        set_busy_status(ssh->frontend, BUSY_NOT);
+
+        hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
+        if (!ssh->kex->pdata) {
+            hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
+            hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
+            hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
+        }
+        hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
+        hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
+
+        dh_cleanup(ssh->kex_ctx);
+        freebn(s->f);
+        if (!ssh->kex->pdata) {
+            freebn(s->g);
+            freebn(s->p);
+        }
     } else {
-       ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP;
-       ssh->kex_ctx = dh_setup_group(ssh->kex);
-       s->kex_init_value = SSH2_MSG_KEXDH_INIT;
-       s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
-       logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
-                 ssh->kex->groupname);
-    }
+       logeventf(ssh, "Doing RSA key exchange with hash %s",
+                 ssh->kex->hash->text_name);
+       ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
+        /*
+         * RSA key exchange. First expect a KEXRSA_PUBKEY packet
+         * from the server.
+         */
+        crWaitUntil(pktin);
+        if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
+            bombout(("expected RSA public key packet from server"));
+            crStop(0);
+        }
 
-    logevent("Doing Diffie-Hellman key exchange");
-    /*
-     * Now generate and send e for Diffie-Hellman.
-     */
-    set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
-    s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
-    s->pktout = ssh2_pkt_init(s->kex_init_value);
-    ssh2_pkt_addmp(s->pktout, s->e);
-    ssh2_pkt_send_noqueue(ssh, s->pktout);
+        ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
+        hash_string(ssh->kex->hash, ssh->exhash,
+                   s->hostkeydata, s->hostkeylen);
+       s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
 
-    set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
-    crWaitUntil(pktin);
-    if (pktin->type != s->kex_reply_value) {
-       bombout(("expected key exchange reply packet from server"));
-       crStop(0);
-    }
-    set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
-    ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
-    s->f = ssh2_pkt_getmp(pktin);
-    if (!s->f) {
-       bombout(("unable to parse key exchange reply packet"));
-       crStop(0);
-    }
-    ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
+        {
+            char *keydata;
+            ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
+            s->rsakeydata = snewn(s->rsakeylen, char);
+            memcpy(s->rsakeydata, keydata, s->rsakeylen);
+        }
+
+        s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
+        if (!s->rsakey) {
+            sfree(s->rsakeydata);
+            bombout(("unable to parse RSA public key from server"));
+            crStop(0);
+        }
+
+        hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
+
+        /*
+         * Next, set up a shared secret K, of precisely KLEN -
+         * 2*HLEN - 49 bits, where KLEN is the bit length of the
+         * RSA key modulus and HLEN is the bit length of the hash
+         * we're using.
+         */
+        {
+            int klen = ssh_rsakex_klen(s->rsakey);
+            int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
+            int i, byte = 0;
+            unsigned char *kstr1, *kstr2, *outstr;
+            int kstr1len, kstr2len, outstrlen;
+
+            s->K = bn_power_2(nbits - 1);
+
+            for (i = 0; i < nbits; i++) {
+                if ((i & 7) == 0) {
+                    byte = random_byte();
+                }
+                bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
+            }
+
+            /*
+             * Encode this as an mpint.
+             */
+            kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
+            kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
+            PUT_32BIT(kstr2, kstr1len);
+            memcpy(kstr2 + 4, kstr1, kstr1len);
+
+            /*
+             * Encrypt it with the given RSA key.
+             */
+            outstrlen = (klen + 7) / 8;
+            outstr = snewn(outstrlen, unsigned char);
+            ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
+                              outstr, outstrlen, s->rsakey);
+
+            /*
+             * And send it off in a return packet.
+             */
+            s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
+            ssh2_pkt_addstring_start(s->pktout);
+            ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
+            ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+           hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
 
-    s->K = dh_find_K(ssh->kex_ctx, s->f);
+            sfree(kstr2);
+            sfree(kstr1);
+            sfree(outstr);
+        }
+
+        ssh_rsakex_freekey(s->rsakey);
+
+        crWaitUntil(pktin);
+        if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
+            sfree(s->rsakeydata);
+            bombout(("expected signature packet from server"));
+            crStop(0);
+        }
 
-    /* We assume everything from now on will be quick, and it might
-     * involve user interaction. */
-    set_busy_status(ssh->frontend, BUSY_NOT);
+        ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
 
-    hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
-    if (!ssh->kex->pdata) {
-       hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
-       hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
-       hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
+        sfree(s->rsakeydata);
     }
-    hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
-    hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
+
     hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
     assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
     ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
 
-    dh_cleanup(ssh->kex_ctx);
     ssh->kex_ctx = NULL;
 
 #if 0
@@ -5553,7 +6037,6 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
     dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
 #endif
 
-    s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
     if (!s->hkey ||
        !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
                                 (char *)s->exchange_hash,
@@ -5644,13 +6127,21 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
      * hash from the _first_ key exchange.
      */
     {
-       unsigned char keyspace[40];
+       unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
+       assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh2_mkkey(ssh,s->K,s->exchange_hash,'C',keyspace);
+       assert((ssh->cscipher->keylen+7) / 8 <=
+              ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
        ssh2_mkkey(ssh,s->K,s->exchange_hash,'A',keyspace);
+       assert(ssh->cscipher->blksize <=
+              ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
        ssh2_mkkey(ssh,s->K,s->exchange_hash,'E',keyspace);
+       assert(ssh->csmac->len <=
+              ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
+       memset(keyspace, 0, sizeof(keyspace));
     }
 
     logeventf(ssh, "Initialised %.200s client->server encryption",
@@ -5702,13 +6193,21 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
      * hash from the _first_ key exchange.
      */
     {
-       unsigned char keyspace[40];
+       unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
+       assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh2_mkkey(ssh,s->K,s->exchange_hash,'D',keyspace);
+       assert((ssh->sccipher->keylen+7) / 8 <=
+              ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
        ssh2_mkkey(ssh,s->K,s->exchange_hash,'B',keyspace);
+       assert(ssh->sccipher->blksize <=
+              ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
        ssh2_mkkey(ssh,s->K,s->exchange_hash,'F',keyspace);
+       assert(ssh->scmac->len <=
+              ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
        ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
+       memset(keyspace, 0, sizeof(keyspace));
     }
     logeventf(ssh, "Initialised %.200s server->client encryption",
              ssh->sccipher->text_name);
@@ -5719,14 +6218,9 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
                  ssh->sccomp->text_name);
 
     /*
-     * Free key exchange data.
+     * Free shared secret.
      */
-    freebn(s->f);
     freebn(s->K);
-    if (!ssh->kex->pdata) {
-       freebn(s->g);
-       freebn(s->p);
-    }
 
     /*
      * Key exchange is over. Loop straight back round if we have a
@@ -5835,8 +6329,8 @@ static int ssh2_try_send(struct ssh_channel *c)
            len = c->v.v2.remmaxpkt;
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
        ssh2_pkt_adduint32(pktout, c->remoteid);
-       dont_log_data(ssh, pktout, PKTLOG_OMIT);
        ssh2_pkt_addstring_start(pktout);
+       dont_log_data(ssh, pktout, PKTLOG_OMIT);
        ssh2_pkt_addstring_data(pktout, data, len);
        end_log_omission(ssh, pktout);
        ssh2_pkt_send(ssh, pktout);
@@ -5878,9 +6372,25 @@ static void ssh2_try_send_and_unthrottle(struct ssh_channel *c)
 }
 
 /*
+ * Set up most of a new ssh_channel for SSH-2.
+ */
+static void ssh2_channel_init(struct ssh_channel *c)
+{
+    Ssh ssh = c->ssh;
+    c->localid = alloc_channel_id(ssh);
+    c->closes = 0;
+    c->throttling_conn = FALSE;
+    c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
+       ssh->cfg.ssh_simple ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
+    c->v.v2.winadj_head = c->v.v2.winadj_tail = NULL;
+    c->v.v2.throttle_state = UNTHROTTLED;
+    bufchain_init(&c->v.v2.outbuffer);
+}
+
+/*
  * Potentially enlarge the window on an SSH-2 channel.
  */
-static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
+static void ssh2_set_window(struct ssh_channel *c, int newwin)
 {
     Ssh ssh = c->ssh;
 
@@ -5893,15 +6403,68 @@ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
        return;
 
     /*
+     * If the remote end has a habit of ignoring maxpkt, limit the
+     * window so that it has no choice (assuming it doesn't ignore the
+     * window as well).
+     */
+    if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
+       newwin = OUR_V2_MAXPKT;
+       
+
+    /*
      * Only send a WINDOW_ADJUST if there's significantly more window
      * available than the other end thinks there is.  This saves us
      * sending a WINDOW_ADJUST for every character in a shell session.
      *
      * "Significant" is arbitrarily defined as half the window size.
      */
-    if (newwin > c->v.v2.locwindow * 2) {
+    if (newwin / 2 >= c->v.v2.locwindow) {
        struct Packet *pktout;
+       struct winadj *wa;
 
+       /*
+        * In order to keep track of how much window the client
+        * actually has available, we'd like it to acknowledge each
+        * WINDOW_ADJUST.  We can't do that directly, so we accompany
+        * it with a CHANNEL_REQUEST that has to be acknowledged.
+        *
+        * This is only necessary if we're opening the window wide.
+        * If we're not, then throughput is being constrained by
+        * something other than the maximum window size anyway.
+        *
+        * We also only send this if the main channel has finished its
+        * initial CHANNEL_REQUESTs and installed the default
+        * CHANNEL_FAILURE handler, so as not to risk giving it
+        * unexpected CHANNEL_FAILUREs.
+        */
+       if (newwin == c->v.v2.locmaxwin &&
+           ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE]) {
+           pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+           ssh2_pkt_adduint32(pktout, c->remoteid);
+           ssh2_pkt_addstring(pktout, "winadj@putty.projects.tartarus.org");
+           ssh2_pkt_addbool(pktout, TRUE);
+           ssh2_pkt_send(ssh, pktout);
+
+           /*
+            * CHANNEL_FAILURE doesn't come with any indication of
+            * what message caused it, so we have to keep track of the
+            * outstanding CHANNEL_REQUESTs ourselves.
+            */
+           wa = snew(struct winadj);
+           wa->size = newwin - c->v.v2.locwindow;
+           wa->next = NULL;
+           if (!c->v.v2.winadj_head)
+               c->v.v2.winadj_head = wa;
+           else
+               c->v.v2.winadj_tail->next = wa;
+           c->v.v2.winadj_tail = wa;
+           if (c->v.v2.throttle_state != UNTHROTTLED)
+               c->v.v2.throttle_state = UNTHROTTLING;
+       } else {
+           /* Pretend the WINDOW_ADJUST was acked immediately. */
+           c->v.v2.remlocwin = newwin;
+           c->v.v2.throttle_state = THROTTLED;
+       }
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
        ssh2_pkt_adduint32(pktout, c->remoteid);
        ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
@@ -5910,12 +6473,94 @@ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
     }
 }
 
+/*
+ * Find the channel associated with a message.  If there's no channel,
+ * or it's not properly open, make a noise about it and return NULL.
+ */
+static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
+{
+    unsigned localid = ssh_pkt_getuint32(pktin);
+    struct ssh_channel *c;
+
+    c = find234(ssh->channels, &localid, ssh_channelfind);
+    if (!c ||
+       (c->halfopen && pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
+        pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
+       char *buf = dupprintf("Received %s for %s channel %u",
+                             ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
+                                           pktin->type),
+                             c ? "half-open" : "nonexistent", localid);
+       ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+       sfree(buf);
+       return NULL;
+    }
+    return c;
+}
+
+static void ssh2_msg_channel_success(Ssh ssh, struct Packet *pktin)
+{
+    /*
+     * This should never get called.  All channel requests are either
+     * sent with want_reply false or are sent before this handler gets
+     * installed.
+     */
+    struct ssh_channel *c;
+    struct winadj *wa;
+
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
+    wa = c->v.v2.winadj_head;
+    if (wa)
+       ssh_disconnect(ssh, NULL, "Received SSH_MSG_CHANNEL_SUCCESS for "
+                      "\"winadj@putty.projects.tartarus.org\"",
+                      SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+    else
+       ssh_disconnect(ssh, NULL,
+                      "Received unsolicited SSH_MSG_CHANNEL_SUCCESS",
+                      SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+}
+
+static void ssh2_msg_channel_failure(Ssh ssh, struct Packet *pktin)
+{
+    /*
+     * The only time this should get called is for "winadj@putty"
+     * messages sent above.  All other channel requests are either
+     * sent with want_reply false or are sent before this handler gets
+     * installed.
+     */
+    struct ssh_channel *c;
+    struct winadj *wa;
+
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
+    wa = c->v.v2.winadj_head;
+    if (!wa) {
+       ssh_disconnect(ssh, NULL,
+                      "Received unsolicited SSH_MSG_CHANNEL_FAILURE",
+                      SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+       return;
+    }
+    c->v.v2.winadj_head = wa->next;
+    c->v.v2.remlocwin += wa->size;
+    sfree(wa);
+    /*
+     * winadj messages are only sent when the window is fully open, so
+     * if we get an ack of one, we know any pending unthrottle is
+     * complete.
+     */
+    if (c->v.v2.throttle_state == UNTHROTTLING)
+       c->v.v2.throttle_state = UNTHROTTLED;
+}
+
 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
-    c = find234(ssh->channels, &i, ssh_channelfind);
-    if (c && !c->closes) {
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
+    if (!c->closes) {
        c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
        ssh2_try_send_and_unthrottle(c);
     }
@@ -5925,11 +6570,10 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
 {
     char *data;
     int length;
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
     if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
        ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
        return;                        /* extended but not stderr */
@@ -5937,6 +6581,7 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
     if (data) {
        int bufsize = 0;
        c->v.v2.locwindow -= length;
+       c->v.v2.remlocwin -= length;
        switch (c->type) {
          case CHAN_MAINSESSION:
            bufsize =
@@ -5953,7 +6598,8 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
          case CHAN_AGENT:
            while (length > 0) {
                if (c->u.a.lensofar < 4) {
-                   unsigned int l = min(4 - c->u.a.lensofar, length);
+                   unsigned int l = min(4 - c->u.a.lensofar,
+                                        (unsigned)length);
                    memcpy(c->u.a.msglen + c->u.a.lensofar,
                           data, l);
                    data += l;
@@ -5970,7 +6616,7 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
                if (c->u.a.lensofar >= 4 && length > 0) {
                    unsigned int l =
                        min(c->u.a.totallen - c->u.a.lensofar,
-                           length);
+                           (unsigned)length);
                    memcpy(c->u.a.message + c->u.a.lensofar,
                           data, l);
                    data += l;
@@ -5993,22 +6639,43 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
            break;
        }
        /*
+        * If it looks like the remote end hit the end of its window,
+        * and we didn't want it to do that, think about using a
+        * larger window.
+        */
+       if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
+           c->v.v2.locmaxwin < 0x40000000)
+           c->v.v2.locmaxwin += OUR_V2_WINSIZE;
+       /*
         * If we are not buffering too much data,
         * enlarge the window again at the remote side.
+        * If we are buffering too much, we may still
+        * need to adjust the window if the server's
+        * sent excess data.
+        */
+       ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
+                       c->v.v2.locmaxwin - bufsize : 0);
+       /*
+        * If we're either buffering way too much data, or if we're
+        * buffering anything at all and we're in "simple" mode,
+        * throttle the whole channel.
         */
-       if (bufsize < OUR_V2_WINSIZE)
-           ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
+       if ((bufsize > c->v.v2.locmaxwin ||
+            (ssh->cfg.ssh_simple && bufsize > 0)) &&
+           !c->throttling_conn) {
+           c->throttling_conn = 1;
+           ssh_throttle_conn(ssh, +1);
+       }
     }
 }
 
 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
 
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
 
     if (c->type == CHAN_X11) {
        /*
@@ -6016,27 +6683,25 @@ static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
         * wrap up and close the channel ourselves.
         */
        x11_close(c->u.x11.s);
+       c->u.x11.s = NULL;
        sshfwd_close(c);
     } else if (c->type == CHAN_AGENT) {
        sshfwd_close(c);
     } else if (c->type == CHAN_SOCKDATA) {
        pfd_close(c->u.pfd.s);
+       c->u.pfd.s = NULL;
        sshfwd_close(c);
     }
 }
 
 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
     struct Packet *pktout;
 
-    c = find234(ssh->channels, &i, ssh_channelfind);
-    if (!c || c->halfopen) {
-       bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
-                c ? "half-open" : "nonexistent", i));
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
        return;
-    }
     /* Do pre-close processing on the channel. */
     switch (c->type) {
       case CHAN_MAINSESSION:
@@ -6089,13 +6754,12 @@ static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
 
 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
     struct Packet *pktout;
 
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
     if (c->type != CHAN_SOCKDATA_DORMANT)
        return;                        /* dunno why they're confirming this */
     c->remoteid = ssh_pkt_getuint32(pktin);
@@ -6127,14 +6791,13 @@ static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
            "Unknown channel type",
            "Resource shortage",
     };
-    unsigned i = ssh_pkt_getuint32(pktin);
     unsigned reason_code;
     char *reason_string;
     int reason_length;
     struct ssh_channel *c;
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
     if (c->type != CHAN_SOCKDATA_DORMANT)
        return;                        /* dunno why they're failing this */
 
@@ -6153,31 +6816,19 @@ static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
 
 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
 {
-    unsigned localid;
     char *type;
     int typelen, want_reply;
     int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
     struct ssh_channel *c;
     struct Packet *pktout;
 
-    localid = ssh_pkt_getuint32(pktin);
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
     ssh_pkt_getstring(pktin, &type, &typelen);
     want_reply = ssh2_pkt_getbool(pktin);
 
     /*
-     * First, check that the channel exists. Otherwise,
-     * we can instantly disconnect with a rude message.
-     */
-    c = find234(ssh->channels, &localid, ssh_channelfind);
-    if (!c) {
-       char *buf = dupprintf("Received channel request for nonexistent"
-                             " channel %d", localid);
-       ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
-       sfree(buf);
-       return;
-    }
-
-    /*
      * Having got the channel number, we now look at
      * the request type string to see if it's something
      * we recognise.
@@ -6204,7 +6855,7 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
            int msglen = 0, core = FALSE;
            /* ICK: older versions of OpenSSH (e.g. 3.4p1)
             * provide an `int' for the signal, despite its
-            * having been a `string' in the drafts since at
+            * having been a `string' in the drafts of RFC 4254 since at
             * least 2001. (Fixed in session.c 1.147.) Try to
             * infer which we can safely parse it as. */
            {
@@ -6239,13 +6890,15 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
                        is_plausible = FALSE;
                }
            }
+           ssh->exitcode = 128;       /* means `unknown signal' */
            if (is_plausible) {
                if (is_int) {
                    /* Old non-standard OpenSSH. */
                    int signum = ssh_pkt_getuint32(pktin);
                    fmt_sig = dupprintf(" %d", signum);
+                   ssh->exitcode = 128 + signum;
                } else {
-                   /* As per the drafts. */
+                   /* As per RFC 4254. */
                    char *sig;
                    int siglen;
                    ssh_pkt_getstring(pktin, &sig, &siglen);
@@ -6255,6 +6908,60 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
                        fmt_sig = dupprintf(" \"%.*s\"",
                                            siglen, sig);
                    }
+
+                   /*
+                    * Really hideous method of translating the
+                    * signal description back into a locally
+                    * meaningful number.
+                    */
+
+                   if (0)
+                       ;
+#define TRANSLATE_SIGNAL(s) \
+    else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
+        ssh->exitcode = 128 + SIG ## s
+#ifdef SIGABRT
+                   TRANSLATE_SIGNAL(ABRT);
+#endif
+#ifdef SIGALRM
+                   TRANSLATE_SIGNAL(ALRM);
+#endif
+#ifdef SIGFPE
+                   TRANSLATE_SIGNAL(FPE);
+#endif
+#ifdef SIGHUP
+                   TRANSLATE_SIGNAL(HUP);
+#endif
+#ifdef SIGILL
+                   TRANSLATE_SIGNAL(ILL);
+#endif
+#ifdef SIGINT
+                   TRANSLATE_SIGNAL(INT);
+#endif
+#ifdef SIGKILL
+                   TRANSLATE_SIGNAL(KILL);
+#endif
+#ifdef SIGPIPE
+                   TRANSLATE_SIGNAL(PIPE);
+#endif
+#ifdef SIGQUIT
+                   TRANSLATE_SIGNAL(QUIT);
+#endif
+#ifdef SIGSEGV
+                   TRANSLATE_SIGNAL(SEGV);
+#endif
+#ifdef SIGTERM
+                   TRANSLATE_SIGNAL(TERM);
+#endif
+#ifdef SIGUSR1
+                   TRANSLATE_SIGNAL(USR1);
+#endif
+#ifdef SIGUSR2
+                   TRANSLATE_SIGNAL(USR2);
+#endif
+#undef TRANSLATE_SIGNAL
+                   else
+                       ssh->exitcode = 128;
                }
                core = ssh2_pkt_getbool(pktin);
                ssh_pkt_getstring(pktin, &msg, &msglen);
@@ -6330,6 +7037,7 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
 
     if (typelen == 3 && !memcmp(type, "x11", 3)) {
        char *addrstr;
+       const char *x11err;
 
        ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
        addrstr = snewn(peeraddrlen+1, char);
@@ -6342,9 +7050,9 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
 
        if (!ssh->X11_fwd_enabled)
            error = "X11 forwarding is not enabled";
-       else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
-                         ssh->x11auth, addrstr, peerport,
-                         &ssh->cfg) != NULL) {
+       else if ((x11err = x11_init(&c->u.x11.s, ssh->x11disp, c,
+                                   addrstr, peerport, &ssh->cfg)) != NULL) {
+           logeventf(ssh, "Local X11 connection failed: %s", x11err);
            error = "Unable to open an X11 connection";
        } else {
            logevent("Opening X11 forward connection succeeded");
@@ -6406,12 +7114,9 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
        logeventf(ssh, "Rejected channel open: %s", error);
        sfree(c);
     } else {
-       c->localid = alloc_channel_id(ssh);
-       c->closes = 0;
-       c->v.v2.locwindow = OUR_V2_WINSIZE;
+       ssh2_channel_init(c);
        c->v.v2.remwindow = winsize;
        c->v.v2.remmaxpkt = pktsize;
-       bufchain_init(&c->v.v2.outbuffer);
        add234(ssh->channels, c);
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
        ssh2_pkt_adduint32(pktout, c->remoteid);
@@ -6465,35 +7170,38 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
 {
     struct do_ssh2_authconn_state {
        enum {
-           AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
-               AUTH_PASSWORD,
-               AUTH_KEYBOARD_INTERACTIVE
-       } method;
-       enum {
            AUTH_TYPE_NONE,
                AUTH_TYPE_PUBLICKEY,
                AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
                AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
                AUTH_TYPE_PASSWORD,
+               AUTH_TYPE_GSSAPI,
                AUTH_TYPE_KEYBOARD_INTERACTIVE,
                AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
        } type;
        int done_service_req;
        int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
-       int tried_pubkey_config, tried_agent;
-       int kbd_inter_running, kbd_inter_refused;
+       int tried_pubkey_config, done_agent;
+#ifndef NO_GSSAPI
+       int can_gssapi;
+       int tried_gssapi;
+#endif
+       int kbd_inter_refused;
        int we_are_in;
-       int num_prompts, curr_prompt, echo;
+       prompts_t *cur_prompt;
+       int num_prompts;
        char username[100];
+       char *password;
        int got_username;
-       char pwprompt[512];
-       char password[100];
        void *publickey_blob;
        int publickey_bloblen;
-       unsigned char request[5], *response, *p;
-       int responselen;
+       int publickey_encrypted;
+       char *publickey_algorithm;
+       char *publickey_comment;
+       unsigned char agent_request[5], *agent_response, *agentp;
+       int agent_responselen;
+       unsigned char *pkblob_in_agent;
        int keyi, nkeys;
-       int authed;
        char *pkblob, *alg, *commentp;
        int pklen, alglen, commentlen;
        int siglen, retlen, len;
@@ -6501,6 +7209,14 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        int try_send;
        int num_env, env_left, env_ok;
        struct Packet *pktout;
+#ifndef NO_GSSAPI
+       struct ssh_gss_library *gsslib;
+       Ssh_gss_ctx gss_ctx;
+       Ssh_gss_buf gss_buf;
+       Ssh_gss_buf gss_rcvtok, gss_sndtok;
+       Ssh_gss_name gss_srv_name;
+       Ssh_gss_stat gss_stat;
+#endif
     };
     crState(do_ssh2_authconn_state);
 
@@ -6508,6 +7224,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
 
     s->done_service_req = FALSE;
     s->we_are_in = FALSE;
+#ifndef NO_GSSAPI
+    s->tried_gssapi = FALSE;
+#endif
+
     if (!ssh->cfg.ssh_no_userauth) {
        /*
         * Request userauth protocol, and await a response to it.
@@ -6535,6 +7255,126 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        }
     }
 
+    /* Arrange to be able to deal with any BANNERs that come in.
+     * (We do this now as packets may come in during the next bit.) */
+    bufchain_init(&ssh->banner);
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
+       ssh2_msg_userauth_banner;
+
+    /*
+     * Misc one-time setup for authentication.
+     */
+    s->publickey_blob = NULL;
+    if (!s->we_are_in) {
+
+       /*
+        * Load the public half of any configured public key file
+        * for later use.
+        */
+       if (!filename_is_null(ssh->cfg.keyfile)) {
+           int keytype;
+           logeventf(ssh, "Reading private key file \"%.150s\"",
+                     filename_to_str(&ssh->cfg.keyfile));
+           keytype = key_type(&ssh->cfg.keyfile);
+           if (keytype == SSH_KEYTYPE_SSH2) {
+               const char *error;
+               s->publickey_blob =
+                   ssh2_userkey_loadpub(&ssh->cfg.keyfile,
+                                        &s->publickey_algorithm,
+                                        &s->publickey_bloblen, 
+                                        &s->publickey_comment, &error);
+               if (s->publickey_blob) {
+                   s->publickey_encrypted =
+                       ssh2_userkey_encrypted(&ssh->cfg.keyfile, NULL);
+               } else {
+                   char *msgbuf;
+                   logeventf(ssh, "Unable to load private key (%s)", 
+                             error);
+                   msgbuf = dupprintf("Unable to load private key file "
+                                      "\"%.150s\" (%s)\r\n",
+                                      filename_to_str(&ssh->cfg.keyfile),
+                                      error);
+                   c_write_str(ssh, msgbuf);
+                   sfree(msgbuf);
+               }
+           } else {
+               char *msgbuf;
+               logeventf(ssh, "Unable to use this key file (%s)",
+                         key_type_to_str(keytype));
+               msgbuf = dupprintf("Unable to use key file \"%.150s\""
+                                  " (%s)\r\n",
+                                  filename_to_str(&ssh->cfg.keyfile),
+                                  key_type_to_str(keytype));
+               c_write_str(ssh, msgbuf);
+               sfree(msgbuf);
+               s->publickey_blob = NULL;
+           }
+       }
+
+       /*
+        * Find out about any keys Pageant has (but if there's a
+        * public key configured, filter out all others).
+        */
+       s->nkeys = 0;
+       s->agent_response = NULL;
+       s->pkblob_in_agent = NULL;
+       if (ssh->cfg.tryagent && agent_exists()) {
+
+           void *r;
+
+           logevent("Pageant is running. Requesting keys.");
+
+           /* Request the keys held by the agent. */
+           PUT_32BIT(s->agent_request, 1);
+           s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
+           if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
+                            ssh_agent_callback, ssh)) {
+               do {
+                   crReturnV;
+                   if (pktin) {
+                       bombout(("Unexpected data from server while"
+                                " waiting for agent response"));
+                       crStopV;
+                   }
+               } while (pktin || inlen > 0);
+               r = ssh->agent_response;
+               s->agent_responselen = ssh->agent_response_len;
+           }
+           s->agent_response = (unsigned char *) r;
+           if (s->agent_response && s->agent_responselen >= 5 &&
+               s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
+               int keyi;
+               unsigned char *p;
+               p = s->agent_response + 5;
+               s->nkeys = GET_32BIT(p);
+               p += 4;
+               logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
+               if (s->publickey_blob) {
+                   /* See if configured key is in agent. */
+                   for (keyi = 0; keyi < s->nkeys; keyi++) {
+                       s->pklen = GET_32BIT(p);
+                       if (s->pklen == s->publickey_bloblen &&
+                           !memcmp(p+4, s->publickey_blob,
+                                   s->publickey_bloblen)) {
+                           logeventf(ssh, "Pageant key #%d matches "
+                                     "configured key file", keyi);
+                           s->keyi = keyi;
+                           s->pkblob_in_agent = p;
+                           break;
+                       }
+                       p += 4 + s->pklen;
+                       p += GET_32BIT(p) + 4; /* comment */
+                   }
+                   if (!s->pkblob_in_agent) {
+                       logevent("Configured key file not in Pageant");
+                       s->nkeys = 0;
+                   }
+               }
+           }
+       }
+
+    }
+
     /*
      * We repeat this whole loop, including the username prompt,
      * until we manage a successful authentication. If the user
@@ -6561,9 +7401,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
      */
     s->username[0] = '\0';
     s->got_username = FALSE;
-    bufchain_init(&ssh->banner);
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
-       ssh2_msg_userauth_banner;
     while (!s->we_are_in) {
        /*
         * Get a username.
@@ -6574,35 +7411,35 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
             * with change_username turned off we don't try to get
             * it again.
             */
-       } else if (!*ssh->cfg.username) {
-           if (ssh_get_line && !ssh_getline_pw_only) {
-               if (!ssh_get_line("login as: ",
-                                 s->username, sizeof(s->username), FALSE)) {
-                   /*
-                    * get_line failed to get a username.
-                    * Terminate.
-                    */
-                   ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
-                   crStopV;
-               }
-           } else {
-               int ret;               /* need not be saved across crReturn */
-               c_write_str(ssh, "login as: ");
+       } else if (!get_remote_username(&ssh->cfg, s->username,
+                                       sizeof(s->username))) {
+           int ret; /* need not be kept over crReturn */
+           s->cur_prompt = new_prompts(ssh->frontend);
+           s->cur_prompt->to_server = TRUE;
+           s->cur_prompt->name = dupstr("SSH login name");
+           add_prompt(s->cur_prompt, dupstr("login as: "), TRUE,
+                      lenof(s->username)); 
+           ret = get_userpass_input(s->cur_prompt, NULL, 0);
+           while (ret < 0) {
                ssh->send_ok = 1;
-               setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
-               do {
-                   crWaitUntilV(!pktin);
-                   ret = process_userpass_input(ssh, in, inlen);
-               } while (ret == 0);
-               if (ret < 0)
-                   cleanup_exit(0);
-               c_write_str(ssh, "\r\n");
+               crWaitUntilV(!pktin);
+               ret = get_userpass_input(s->cur_prompt, in, inlen);
+               ssh->send_ok = 0;
+           }
+           if (!ret) {
+               /*
+                * get_userpass_input() failed to get a username.
+                * Terminate.
+                */
+               free_prompts(s->cur_prompt);
+               ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
+               crStopV;
            }
-           s->username[strcspn(s->username, "\n\r")] = '\0';
+           memcpy(s->username, s->cur_prompt->prompts[0]->result,
+                  lenof(s->username));
+           free_prompts(s->cur_prompt);
        } else {
            char *stuff;
-           strncpy(s->username, ssh->cfg.username, sizeof(s->username));
-           s->username[sizeof(s->username)-1] = '\0';
            if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
                stuff = dupprintf("Using username \"%s\".\r\n", s->username);
                c_write_str(ssh, stuff);
@@ -6616,7 +7453,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
         * just in case it succeeds, and (b) so that we know what
         * authentication methods we can usefully try next.
         */
-       ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
+       ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
 
        s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
        ssh2_pkt_addstring(s->pktout, s->username);
@@ -6628,33 +7465,18 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        s->we_are_in = FALSE;
 
        s->tried_pubkey_config = FALSE;
-       s->tried_agent = FALSE;
-       s->kbd_inter_running = FALSE;
        s->kbd_inter_refused = FALSE;
-       /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
-       if (!filename_is_null(ssh->cfg.keyfile)) {
-           int keytype;
-           logeventf(ssh, "Reading private key file \"%.150s\"",
-                     filename_to_str(&ssh->cfg.keyfile));
-           keytype = key_type(&ssh->cfg.keyfile);
-           if (keytype == SSH_KEYTYPE_SSH2) {
-               s->publickey_blob =
-                   ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
-                                        &s->publickey_bloblen, NULL);
+
+       /* Reset agent request state. */
+       s->done_agent = FALSE;
+       if (s->agent_response) {
+           if (s->pkblob_in_agent) {
+               s->agentp = s->pkblob_in_agent;
            } else {
-               char *msgbuf;
-               logeventf(ssh, "Unable to use this key file (%s)",
-                         key_type_to_str(keytype));
-               msgbuf = dupprintf("Unable to use key file \"%.150s\""
-                                  " (%s)\r\n",
-                                  filename_to_str(&ssh->cfg.keyfile),
-                                  key_type_to_str(keytype));
-               c_write_str(ssh, msgbuf);
-               sfree(msgbuf);
-               s->publickey_blob = NULL;
+               s->agentp = s->agent_response + 5 + 4;
+               s->keyi = 0;
            }
-       } else
-           s->publickey_blob = NULL;
+       }
 
        while (1) {
            /*
@@ -6692,24 +7514,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                break;
            }
 
-           if (s->kbd_inter_running &&
-               pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
-               /*
-                * This is either a further set-of-prompts packet
-                * in keyboard-interactive authentication, or it's
-                * the same one and we came back here with `gotit'
-                * set. In the former case, we must reset the
-                * curr_prompt variable.
-                */
-               if (!s->gotit)
-                   s->curr_prompt = 0;
-           } else if (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
-               /* FIXME: perhaps we should support this? */
-               bombout(("PASSWD_CHANGEREQ not yet supported"));
-               crStopV;
-           } else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
-               bombout(("Strange packet received during authentication: type %d",
-                        pktin->type));
+           if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
+               bombout(("Strange packet received during authentication: "
+                        "type %d", pktin->type));
                crStopV;
            }
 
@@ -6724,7 +7531,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                char *methods;
                int methlen;
                ssh_pkt_getstring(pktin, &methods, &methlen);
-               s->kbd_inter_running = FALSE;
                if (!ssh2_pkt_getbool(pktin)) {
                    /*
                     * We have received an unequivocal Access
@@ -6779,198 +7585,172 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    in_commasep_string("password", methods, methlen);
                s->can_keyb_inter = ssh->cfg.try_ki_auth &&
                    in_commasep_string("keyboard-interactive", methods, methlen);
+#ifndef NO_GSSAPI              
+               ssh_gss_init();
+               s->can_gssapi = ssh->cfg.try_gssapi_auth &&
+                   in_commasep_string("gssapi-with-mic", methods, methlen) &&
+                   n_ssh_gss_libraries > 0;
+#endif
            }
 
-           s->method = 0;
-           ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-           s->need_pw = FALSE;
+           ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
 
-           /*
-            * Most password/passphrase prompts will be
-            * non-echoing, so we set this to 0 by default.
-            * Exception is that some keyboard-interactive prompts
-            * can be echoing, in which case we'll set this to 1.
-            */
-           s->echo = 0;
+           if (s->can_pubkey && !s->done_agent && s->nkeys) {
 
-           if (!s->method && s->can_pubkey &&
-               agent_exists() && !s->tried_agent) {
                /*
-                * Attempt public-key authentication using Pageant.
+                * Attempt public-key authentication using a key from Pageant.
                 */
-               void *r;
-               s->authed = FALSE;
-
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
-
-               s->tried_agent = TRUE;
-
-               logevent("Pageant is running. Requesting keys.");
-
-               /* Request the keys held by the agent. */
-               PUT_32BIT(s->request, 1);
-               s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
-               if (!agent_query(s->request, 5, &r, &s->responselen,
-                                ssh_agent_callback, ssh)) {
-                   do {
-                       crReturnV;
-                       if (pktin) {
-                           bombout(("Unexpected data from server while"
-                                    " waiting for agent response"));
-                           crStopV;
-                       }
-                   } while (pktin || inlen > 0);
-                   r = ssh->agent_response;
-                   s->responselen = ssh->agent_response_len;
-               }
-               s->response = (unsigned char *) r;
-               if (s->response && s->responselen >= 5 &&
-                   s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
-                   s->p = s->response + 5;
-                   s->nkeys = GET_32BIT(s->p);
-                   s->p += 4;
-                   logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
-                   for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
-                       void *vret;
 
-                       logeventf(ssh, "Trying Pageant key #%d", s->keyi);
-                       s->pklen = GET_32BIT(s->p);
-                       s->p += 4;
-                       if (s->publickey_blob &&
-                           s->pklen == s->publickey_bloblen &&
-                           !memcmp(s->p, s->publickey_blob,
-                                   s->publickey_bloblen)) {
-                           logevent("This key matches configured key file");
-                           s->tried_pubkey_config = 1;
-                       }
-                       s->pkblob = (char *)s->p;
-                       s->p += s->pklen;
-                       s->alglen = GET_32BIT(s->pkblob);
-                       s->alg = s->pkblob + 4;
-                       s->commentlen = GET_32BIT(s->p);
-                       s->p += 4;
-                       s->commentp = (char *)s->p;
-                       s->p += s->commentlen;
-                       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
-                       ssh2_pkt_addstring(s->pktout, s->username);
-                       ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
-                       ssh2_pkt_addstring(s->pktout, "publickey");     /* method */
-                       ssh2_pkt_addbool(s->pktout, FALSE);     /* no signature included */
-                       ssh2_pkt_addstring_start(s->pktout);
-                       ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
-                       ssh2_pkt_addstring_start(s->pktout);
-                       ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
-                       ssh2_pkt_send(ssh, s->pktout);
+               ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
 
-                       crWaitUntilV(pktin);
-                       if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
-                           logevent("Key refused");
-                           continue;
-                       }
+               logeventf(ssh, "Trying Pageant key #%d", s->keyi);
 
-                       if (flags & FLAG_VERBOSE) {
-                           c_write_str(ssh, "Authenticating with "
-                                       "public key \"");
-                           c_write(ssh, s->commentp, s->commentlen);
-                           c_write_str(ssh, "\" from agent\r\n");
-                       }
+               /* Unpack key from agent response */
+               s->pklen = GET_32BIT(s->agentp);
+               s->agentp += 4;
+               s->pkblob = (char *)s->agentp;
+               s->agentp += s->pklen;
+               s->alglen = GET_32BIT(s->pkblob);
+               s->alg = s->pkblob + 4;
+               s->commentlen = GET_32BIT(s->agentp);
+               s->agentp += 4;
+               s->commentp = (char *)s->agentp;
+               s->agentp += s->commentlen;
+               /* s->agentp now points at next key, if any */
 
-                       /*
-                        * Server is willing to accept the key.
-                        * Construct a SIGN_REQUEST.
-                        */
-                       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
-                       ssh2_pkt_addstring(s->pktout, s->username);
-                       ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
-                       ssh2_pkt_addstring(s->pktout, "publickey");     /* method */
-                       ssh2_pkt_addbool(s->pktout, TRUE);
-                       ssh2_pkt_addstring_start(s->pktout);
-                       ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
-                       ssh2_pkt_addstring_start(s->pktout);
-                       ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
-
-                       s->siglen = s->pktout->length - 5 + 4 +
-                           ssh->v2_session_id_len;
-                        if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
-                            s->siglen -= 4;
-                       s->len = 1;       /* message type */
-                       s->len += 4 + s->pklen; /* key blob */
-                       s->len += 4 + s->siglen;        /* data to sign */
-                       s->len += 4;      /* flags */
-                       s->agentreq = snewn(4 + s->len, char);
-                       PUT_32BIT(s->agentreq, s->len);
-                       s->q = s->agentreq + 4;
-                       *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
-                       PUT_32BIT(s->q, s->pklen);
-                       s->q += 4;
-                       memcpy(s->q, s->pkblob, s->pklen);
-                       s->q += s->pklen;
-                       PUT_32BIT(s->q, s->siglen);
+               /* See if server will accept it */
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+               ssh2_pkt_addstring(s->pktout, s->username);
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                                   /* service requested */
+               ssh2_pkt_addstring(s->pktout, "publickey");
+                                                   /* method */
+               ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
+               ssh2_pkt_addstring_start(s->pktout);
+               ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
+               ssh2_pkt_addstring_start(s->pktout);
+               ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
+               ssh2_pkt_send(ssh, s->pktout);
+               s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
+
+               crWaitUntilV(pktin);
+               if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
+
+                   /* Offer of key refused. */
+                   s->gotit = TRUE;
+
+               } else {
+                   
+                   void *vret;
+
+                   if (flags & FLAG_VERBOSE) {
+                       c_write_str(ssh, "Authenticating with "
+                                   "public key \"");
+                       c_write(ssh, s->commentp, s->commentlen);
+                       c_write_str(ssh, "\" from agent\r\n");
+                   }
+
+                   /*
+                    * Server is willing to accept the key.
+                    * Construct a SIGN_REQUEST.
+                    */
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                   ssh2_pkt_addstring(s->pktout, s->username);
+                   ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                                       /* service requested */
+                   ssh2_pkt_addstring(s->pktout, "publickey");
+                                                       /* method */
+                   ssh2_pkt_addbool(s->pktout, TRUE);  /* signature included */
+                   ssh2_pkt_addstring_start(s->pktout);
+                   ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
+                   ssh2_pkt_addstring_start(s->pktout);
+                   ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
+
+                   /* Ask agent for signature. */
+                   s->siglen = s->pktout->length - 5 + 4 +
+                       ssh->v2_session_id_len;
+                   if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
+                       s->siglen -= 4;
+                   s->len = 1;       /* message type */
+                   s->len += 4 + s->pklen;     /* key blob */
+                   s->len += 4 + s->siglen;    /* data to sign */
+                   s->len += 4;      /* flags */
+                   s->agentreq = snewn(4 + s->len, char);
+                   PUT_32BIT(s->agentreq, s->len);
+                   s->q = s->agentreq + 4;
+                   *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
+                   PUT_32BIT(s->q, s->pklen);
+                   s->q += 4;
+                   memcpy(s->q, s->pkblob, s->pklen);
+                   s->q += s->pklen;
+                   PUT_32BIT(s->q, s->siglen);
+                   s->q += 4;
+                   /* Now the data to be signed... */
+                   if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
+                       PUT_32BIT(s->q, ssh->v2_session_id_len);
                        s->q += 4;
-                       /* Now the data to be signed... */
-                        if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
-                            PUT_32BIT(s->q, ssh->v2_session_id_len);
-                            s->q += 4;
-                        }
-                       memcpy(s->q, ssh->v2_session_id,
-                              ssh->v2_session_id_len);
-                       s->q += ssh->v2_session_id_len;
-                       memcpy(s->q, s->pktout->data + 5,
-                              s->pktout->length - 5);
-                       s->q += s->pktout->length - 5;
-                       /* And finally the (zero) flags word. */
-                       PUT_32BIT(s->q, 0);
-                       if (!agent_query(s->agentreq, s->len + 4,
-                                        &vret, &s->retlen,
-                                        ssh_agent_callback, ssh)) {
-                           do {
-                               crReturnV;
-                               if (pktin) {
-                                   bombout(("Unexpected data from server"
-                                            " while waiting for agent"
-                                            " response"));
-                                   crStopV;
-                               }
-                           } while (pktin || inlen > 0);
-                           vret = ssh->agent_response;
-                           s->retlen = ssh->agent_response_len;
-                       }
-                       s->ret = vret;
-                       sfree(s->agentreq);
-                       if (s->ret) {
-                           if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
-                               logevent("Sending Pageant's response");
-                               ssh2_add_sigblob(ssh, s->pktout,
-                                                s->pkblob, s->pklen,
-                                                s->ret + 9,
-                                                GET_32BIT(s->ret + 5));
-                               ssh2_pkt_send(ssh, s->pktout);
-                               s->authed = TRUE;
-                               break;
-                           } else {
-                               logevent
-                                   ("Pageant failed to answer challenge");
-                               sfree(s->ret);
+                   }
+                   memcpy(s->q, ssh->v2_session_id,
+                          ssh->v2_session_id_len);
+                   s->q += ssh->v2_session_id_len;
+                   memcpy(s->q, s->pktout->data + 5,
+                          s->pktout->length - 5);
+                   s->q += s->pktout->length - 5;
+                   /* And finally the (zero) flags word. */
+                   PUT_32BIT(s->q, 0);
+                   if (!agent_query(s->agentreq, s->len + 4,
+                                    &vret, &s->retlen,
+                                    ssh_agent_callback, ssh)) {
+                       do {
+                           crReturnV;
+                           if (pktin) {
+                               bombout(("Unexpected data from server"
+                                        " while waiting for agent"
+                                        " response"));
+                               crStopV;
                            }
+                       } while (pktin || inlen > 0);
+                       vret = ssh->agent_response;
+                       s->retlen = ssh->agent_response_len;
+                   }
+                   s->ret = vret;
+                   sfree(s->agentreq);
+                   if (s->ret) {
+                       if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
+                           logevent("Sending Pageant's response");
+                           ssh2_add_sigblob(ssh, s->pktout,
+                                            s->pkblob, s->pklen,
+                                            s->ret + 9,
+                                            GET_32BIT(s->ret + 5));
+                           ssh2_pkt_send(ssh, s->pktout);
+                           s->type = AUTH_TYPE_PUBLICKEY;
+                       } else {
+                           /* FIXME: less drastic response */
+                           bombout(("Pageant failed to answer challenge"));
+                           crStopV;
                        }
                    }
-                   if (s->authed)
-                       continue;
                }
-               sfree(s->response);
-           }
 
-           if (!s->method && s->can_pubkey && s->publickey_blob
-               && !s->tried_pubkey_config) {
-               unsigned char *pub_blob;
-               char *algorithm, *comment;
-               int pub_blob_len;
+               /* Do we have any keys left to try? */
+               if (s->pkblob_in_agent) {
+                   s->done_agent = TRUE;
+                   s->tried_pubkey_config = TRUE;
+               } else {
+                   s->keyi++;
+                   if (s->keyi >= s->nkeys)
+                       s->done_agent = TRUE;
+               }
+
+           } else if (s->can_pubkey && s->publickey_blob &&
+                      !s->tried_pubkey_config) {
 
-               s->tried_pubkey_config = TRUE;
+               struct ssh2_userkey *key;   /* not live over crReturn */
+               char *passphrase;           /* not live over crReturn */
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
+               ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
+
+               s->tried_pubkey_config = TRUE;
 
                /*
                 * Try the public key supplied in the configuration.
@@ -6978,270 +7758,556 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                 * First, offer the public blob to see if the server is
                 * willing to accept it.
                 */
-               pub_blob =
-                   (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
-                                                         &algorithm,
-                                                         &pub_blob_len,
-                                                         NULL);
-               if (pub_blob) {
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+               ssh2_pkt_addstring(s->pktout, s->username);
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                               /* service requested */
+               ssh2_pkt_addstring(s->pktout, "publickey");     /* method */
+               ssh2_pkt_addbool(s->pktout, FALSE);
+                                               /* no signature included */
+               ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
+               ssh2_pkt_addstring_start(s->pktout);
+               ssh2_pkt_addstring_data(s->pktout,
+                                       (char *)s->publickey_blob,
+                                       s->publickey_bloblen);
+               ssh2_pkt_send(ssh, s->pktout);
+               logevent("Offered public key");
+
+               crWaitUntilV(pktin);
+               if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
+                   /* Key refused. Give up. */
+                   s->gotit = TRUE; /* reconsider message next loop */
+                   s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
+                   continue; /* process this new message */
+               }
+               logevent("Offer of public key accepted");
+
+               /*
+                * Actually attempt a serious authentication using
+                * the key.
+                */
+               if (flags & FLAG_VERBOSE) {
+                   c_write_str(ssh, "Authenticating with public key \"");
+                   c_write_str(ssh, s->publickey_comment);
+                   c_write_str(ssh, "\"\r\n");
+               }
+               key = NULL;
+               while (!key) {
+                   const char *error;  /* not live over crReturn */
+                   if (s->publickey_encrypted) {
+                       /*
+                        * Get a passphrase from the user.
+                        */
+                       int ret; /* need not be kept over crReturn */
+                       s->cur_prompt = new_prompts(ssh->frontend);
+                       s->cur_prompt->to_server = FALSE;
+                       s->cur_prompt->name = dupstr("SSH key passphrase");
+                       add_prompt(s->cur_prompt,
+                                  dupprintf("Passphrase for key \"%.100s\": ",
+                                            s->publickey_comment),
+                                  FALSE, SSH_MAX_PASSWORD_LEN);
+                       ret = get_userpass_input(s->cur_prompt, NULL, 0);
+                       while (ret < 0) {
+                           ssh->send_ok = 1;
+                           crWaitUntilV(!pktin);
+                           ret = get_userpass_input(s->cur_prompt,
+                                                    in, inlen);
+                           ssh->send_ok = 0;
+                       }
+                       if (!ret) {
+                           /* Failed to get a passphrase. Terminate. */
+                           free_prompts(s->cur_prompt);
+                           ssh_disconnect(ssh, NULL,
+                                          "Unable to authenticate",
+                                          SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
+                                          TRUE);
+                           crStopV;
+                       }
+                       passphrase =
+                           dupstr(s->cur_prompt->prompts[0]->result);
+                       free_prompts(s->cur_prompt);
+                   } else {
+                       passphrase = NULL; /* no passphrase needed */
+                   }
+
+                   /*
+                    * Try decrypting the key.
+                    */
+                   key = ssh2_load_userkey(&ssh->cfg.keyfile, passphrase,
+                                           &error);
+                   if (passphrase) {
+                       /* burn the evidence */
+                       memset(passphrase, 0, strlen(passphrase));
+                       sfree(passphrase);
+                   }
+                   if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
+                       if (passphrase &&
+                           (key == SSH2_WRONG_PASSPHRASE)) {
+                           c_write_str(ssh, "Wrong passphrase\r\n");
+                           key = NULL;
+                           /* and loop again */
+                       } else {
+                           c_write_str(ssh, "Unable to load private key (");
+                           c_write_str(ssh, error);
+                           c_write_str(ssh, ")\r\n");
+                           key = NULL;
+                           break; /* try something else */
+                       }
+                   }
+               }
+
+               if (key) {
+                   unsigned char *pkblob, *sigblob, *sigdata;
+                   int pkblob_len, sigblob_len, sigdata_len;
+                   int p;
+
+                   /*
+                    * We have loaded the private key and the server
+                    * has announced that it's willing to accept it.
+                    * Hallelujah. Generate a signature and send it.
+                    */
                    s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
                    ssh2_pkt_addstring(s->pktout, s->username);
-                   ssh2_pkt_addstring(s->pktout, "ssh-connection");    /* service requested */
-                   ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
-                   ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
-                   ssh2_pkt_addstring(s->pktout, algorithm);
+                   ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                                   /* service requested */
+                   ssh2_pkt_addstring(s->pktout, "publickey");
+                                                   /* method */
+                   ssh2_pkt_addbool(s->pktout, TRUE);
+                                                   /* signature follows */
+                   ssh2_pkt_addstring(s->pktout, key->alg->name);
+                   pkblob = key->alg->public_blob(key->data,
+                                                  &pkblob_len);
                    ssh2_pkt_addstring_start(s->pktout);
-                   ssh2_pkt_addstring_data(s->pktout, (char *)pub_blob,
-                                           pub_blob_len);
+                   ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
+                                           pkblob_len);
+
+                   /*
+                    * The data to be signed is:
+                    *
+                    *   string  session-id
+                    *
+                    * followed by everything so far placed in the
+                    * outgoing packet.
+                    */
+                   sigdata_len = s->pktout->length - 5 + 4 +
+                       ssh->v2_session_id_len;
+                   if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
+                       sigdata_len -= 4;
+                   sigdata = snewn(sigdata_len, unsigned char);
+                   p = 0;
+                   if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
+                       PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
+                       p += 4;
+                   }
+                   memcpy(sigdata+p, ssh->v2_session_id,
+                          ssh->v2_session_id_len);
+                   p += ssh->v2_session_id_len;
+                   memcpy(sigdata+p, s->pktout->data + 5,
+                          s->pktout->length - 5);
+                   p += s->pktout->length - 5;
+                   assert(p == sigdata_len);
+                   sigblob = key->alg->sign(key->data, (char *)sigdata,
+                                            sigdata_len, &sigblob_len);
+                   ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
+                                    sigblob, sigblob_len);
+                   sfree(pkblob);
+                   sfree(sigblob);
+                   sfree(sigdata);
+
                    ssh2_pkt_send(ssh, s->pktout);
-                   logevent("Offered public key");
+                   s->type = AUTH_TYPE_PUBLICKEY;
+                   key->alg->freekey(key->data);
+               }
+
+#ifndef NO_GSSAPI
+           } else if (s->can_gssapi && !s->tried_gssapi) {
+
+               /* GSSAPI Authentication */
+
+               int micoffset, len;
+               char *data;
+               Ssh_gss_buf mic;
+               s->type = AUTH_TYPE_GSSAPI;
+               s->tried_gssapi = TRUE;
+               s->gotit = TRUE;
+               ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
+
+               /*
+                * Pick the highest GSS library on the preference
+                * list.
+                */
+               {
+                   int i, j;
+                   s->gsslib = NULL;
+                   for (i = 0; i < ngsslibs; i++) {
+                       int want_id = ssh->cfg.ssh_gsslist[i];
+                       for (j = 0; j < n_ssh_gss_libraries; j++)
+                           if (ssh_gss_libraries[j].id == want_id) {
+                               s->gsslib = &ssh_gss_libraries[j];
+                               goto got_gsslib;   /* double break */
+                           }
+                   }
+                   got_gsslib:
+                   /*
+                    * We always expect to have found something in
+                    * the above loop: we only came here if there
+                    * was at least one viable GSS library, and the
+                    * preference list should always mention
+                    * everything and only change the order.
+                    */
+                   assert(s->gsslib);
+               }
+
+               if (s->gsslib->gsslogmsg)
+                   logevent(s->gsslib->gsslogmsg);
+
+               /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+               ssh2_pkt_addstring(s->pktout, s->username);
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");
+               ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
+
+               /* add mechanism info */
+               s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
+
+               /* number of GSSAPI mechanisms */
+               ssh2_pkt_adduint32(s->pktout,1);
+
+               /* length of OID + 2 */
+               ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
+               ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
+
+               /* length of OID */
+               ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
+
+               ssh_pkt_adddata(s->pktout, s->gss_buf.value,
+                               s->gss_buf.length);
+               ssh2_pkt_send(ssh, s->pktout);
+               crWaitUntilV(pktin);
+               if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
+                   logevent("GSSAPI authentication request refused");
+                   continue;
+               }
+
+               /* check returned packet ... */
+
+               ssh_pkt_getstring(pktin, &data, &len);
+               s->gss_rcvtok.value = data;
+               s->gss_rcvtok.length = len;
+               if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
+                   ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
+                   ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
+                   memcmp((char *)s->gss_rcvtok.value + 2,
+                          s->gss_buf.value,s->gss_buf.length) ) {
+                   logevent("GSSAPI authentication - wrong response from server");
+                   continue;
+               }
+
+               /* now start running */
+               s->gss_stat = s->gsslib->import_name(s->gsslib,
+                                                    ssh->fullhostname,
+                                                    &s->gss_srv_name);
+               if (s->gss_stat != SSH_GSS_OK) {
+                   if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
+                       logevent("GSSAPI import name failed - Bad service name");
+                   else
+                       logevent("GSSAPI import name failed");
+                   continue;
+               }
+
+               /* fetch TGT into GSS engine */
+               s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
+
+               if (s->gss_stat != SSH_GSS_OK) {
+                   logevent("GSSAPI authentication failed to get credentials");
+                   s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
+                   continue;
+               }
 
-                   crWaitUntilV(pktin);
-                   if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
-                       s->gotit = TRUE;
-                       s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
-                       continue;      /* key refused; give up on it */
+               /* initial tokens are empty */
+               SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
+               SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
+
+               /* now enter the loop */
+               do {
+                   s->gss_stat = s->gsslib->init_sec_context
+                       (s->gsslib,
+                        &s->gss_ctx,
+                        s->gss_srv_name,
+                        ssh->cfg.gssapifwd,
+                        &s->gss_rcvtok,
+                        &s->gss_sndtok);
+
+                   if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
+                       s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
+                       logevent("GSSAPI authentication initialisation failed");
+
+                       if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
+                                                     &s->gss_buf) == SSH_GSS_OK) {
+                           logevent(s->gss_buf.value);
+                           sfree(s->gss_buf.value);
+                       }
+
+                       break;
                    }
+                   logevent("GSSAPI authentication initialised");
 
-                   logevent("Offer of public key accepted");
-                   /*
-                    * Actually attempt a serious authentication using
-                    * the key.
-                    */
-                   if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
-                       sprintf(s->pwprompt,
-                               "Passphrase for key \"%.100s\": ",
-                               comment);
-                       s->need_pw = TRUE;
-                   } else {
-                       s->need_pw = FALSE;
+                   /* Client and server now exchange tokens until GSSAPI
+                    * no longer says CONTINUE_NEEDED */
+
+                   if (s->gss_sndtok.length != 0) {
+                       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
+                       ssh_pkt_addstring_start(s->pktout);
+                       ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
+                       ssh2_pkt_send(ssh, s->pktout);
+                       s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
                    }
-                   if (flags & FLAG_VERBOSE) {
-                       c_write_str(ssh, "Authenticating with public key \"");
-                       c_write_str(ssh, comment);
-                       c_write_str(ssh, "\"\r\n");
+
+                   if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
+                       crWaitUntilV(pktin);
+                       if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
+                           logevent("GSSAPI authentication - bad server response");
+                           s->gss_stat = SSH_GSS_FAILURE;
+                           break;
+                       }
+                       ssh_pkt_getstring(pktin, &data, &len);
+                       s->gss_rcvtok.value = data;
+                       s->gss_rcvtok.length = len;
                    }
-                   s->method = AUTH_PUBLICKEY_FILE;
+               } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
+
+               if (s->gss_stat != SSH_GSS_OK) {
+                   s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
+                   s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
+                   continue;
                }
-           }
+               logevent("GSSAPI authentication loop finished OK");
+
+               /* Now send the MIC */
+
+               s->pktout = ssh2_pkt_init(0);
+               micoffset = s->pktout->length;
+               ssh_pkt_addstring_start(s->pktout);
+               ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
+               ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
+               ssh_pkt_addstring(s->pktout, s->username);
+               ssh_pkt_addstring(s->pktout, "ssh-connection");
+               ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
+
+               s->gss_buf.value = (char *)s->pktout->data + micoffset;
+               s->gss_buf.length = s->pktout->length - micoffset;
+
+               s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
+               ssh_pkt_addstring_start(s->pktout);
+               ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
+               ssh2_pkt_send(ssh, s->pktout);
+               s->gsslib->free_mic(s->gsslib, &mic);
+
+               s->gotit = FALSE;
+
+               s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
+               s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
+               continue;
+#endif
+           } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
+
+               /*
+                * Keyboard-interactive authentication.
+                */
 
-           if (!s->method && s->can_keyb_inter && !s->kbd_inter_refused &&
-               !s->kbd_inter_running) {
-               s->method = AUTH_KEYBOARD_INTERACTIVE;
                s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
+               ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
 
                s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
                ssh2_pkt_addstring(s->pktout, s->username);
-               ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
-               ssh2_pkt_addstring(s->pktout, "keyboard-interactive");  /* method */
-               ssh2_pkt_addstring(s->pktout, ""); /* lang */
-               ssh2_pkt_addstring(s->pktout, "");
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                                       /* service requested */
+               ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
+                                                       /* method */
+               ssh2_pkt_addstring(s->pktout, "");      /* lang */
+               ssh2_pkt_addstring(s->pktout, "");      /* submethods */
                ssh2_pkt_send(ssh, s->pktout);
 
                crWaitUntilV(pktin);
                if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
+                   /* Server is not willing to do keyboard-interactive
+                    * at all (or, bizarrely but legally, accepts the
+                    * user without actually issuing any prompts).
+                    * Give up on it entirely. */
+                   s->gotit = TRUE;
                    if (pktin->type == SSH2_MSG_USERAUTH_FAILURE)
-                       s->gotit = TRUE;
-                   logevent("Keyboard-interactive authentication refused");
+                       logevent("Keyboard-interactive authentication refused");
                    s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
                    s->kbd_inter_refused = TRUE; /* don't try it again */
                    continue;
                }
 
-               c_write_str(ssh, "Using keyboard-interactive authentication.\r\n");
-               s->kbd_inter_running = TRUE;
-               s->curr_prompt = 0;
-           }
-
-           if (s->kbd_inter_running) {
-               s->method = AUTH_KEYBOARD_INTERACTIVE;
-               s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
+               /*
+                * Loop while the server continues to send INFO_REQUESTs.
+                */
+               while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
+                   char *name, *inst, *lang;
+                   int name_len, inst_len, lang_len;
+                   int i;
 
-               if (s->curr_prompt == 0) {
                    /*
                     * We've got a fresh USERAUTH_INFO_REQUEST.
-                    * Display header data, and start going through
-                    * the prompts.
+                    * Get the preamble and start building a prompt.
                     */
-                   char *name, *inst, *lang;
-                   int name_len, inst_len, lang_len;
-
                    ssh_pkt_getstring(pktin, &name, &name_len);
                    ssh_pkt_getstring(pktin, &inst, &inst_len);
                    ssh_pkt_getstring(pktin, &lang, &lang_len);
-                   if (name_len > 0) {
-                       c_write_untrusted(ssh, name, name_len);
-                       c_write_str(ssh, "\r\n");
-                   }
-                   if (inst_len > 0) {
-                       c_write_untrusted(ssh, inst, inst_len);
-                       c_write_str(ssh, "\r\n");
-                   }
-                   s->num_prompts = ssh_pkt_getuint32(pktin);
-               }
-
-               /*
-                * If there are prompts remaining in the packet,
-                * display one and get a response.
-                */
-               if (s->curr_prompt < s->num_prompts) {
-                   char *prompt;
-                   int prompt_len;
+                   s->cur_prompt = new_prompts(ssh->frontend);
+                   s->cur_prompt->to_server = TRUE;
 
-                   ssh_pkt_getstring(pktin, &prompt, &prompt_len);
-                   if (prompt_len > 0) {
-                       static const char trunc[] = "<prompt truncated>: ";
-                       static const int prlen = sizeof(s->pwprompt) -
-                                                lenof(trunc);
-                       if (prompt_len > prlen) {
-                           memcpy(s->pwprompt, prompt, prlen);
-                           strcpy(s->pwprompt + prlen, trunc);
-                       } else {
-                           memcpy(s->pwprompt, prompt, prompt_len);
-                           s->pwprompt[prompt_len] = '\0';
+                   /*
+                    * Get any prompt(s) from the packet.
+                    */
+                   s->num_prompts = ssh_pkt_getuint32(pktin);
+                   for (i = 0; i < s->num_prompts; i++) {
+                       char *prompt;
+                       int prompt_len;
+                       int echo;
+                       static char noprompt[] =
+                           "<server failed to send prompt>: ";
+
+                       ssh_pkt_getstring(pktin, &prompt, &prompt_len);
+                       echo = ssh2_pkt_getbool(pktin);
+                       if (!prompt_len) {
+                           prompt = noprompt;
+                           prompt_len = lenof(noprompt)-1;
                        }
+                       add_prompt(s->cur_prompt,
+                                  dupprintf("%.*s", prompt_len, prompt),
+                                  echo, SSH_MAX_PASSWORD_LEN);
+                   }
+
+                   if (name_len) {
+                       /* FIXME: better prefix to distinguish from
+                        * local prompts? */
+                       s->cur_prompt->name =
+                           dupprintf("SSH server: %.*s", name_len, name);
+                       s->cur_prompt->name_reqd = TRUE;
                    } else {
-                       strcpy(s->pwprompt,
-                              "<server failed to send prompt>: ");
+                       s->cur_prompt->name =
+                           dupstr("SSH server authentication");
+                       s->cur_prompt->name_reqd = FALSE;
+                   }
+                   /* We add a prefix to try to make it clear that a prompt
+                    * has come from the server.
+                    * FIXME: ugly to print "Using..." in prompt _every_
+                    * time round. Can this be done more subtly? */
+                   /* Special case: for reasons best known to themselves,
+                    * some servers send k-i requests with no prompts and
+                    * nothing to display. Keep quiet in this case. */
+                   if (s->num_prompts || name_len || inst_len) {
+                       s->cur_prompt->instruction =
+                           dupprintf("Using keyboard-interactive authentication.%s%.*s",
+                                     inst_len ? "\n" : "", inst_len, inst);
+                       s->cur_prompt->instr_reqd = TRUE;
+                   } else {
+                       s->cur_prompt->instr_reqd = FALSE;
                    }
-                   s->echo = ssh2_pkt_getbool(pktin);
-                   s->need_pw = TRUE;
-               } else
-                   s->need_pw = FALSE;
-           }
 
-           if (!s->method && s->can_passwd) {
-               s->method = AUTH_PASSWORD;
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
-               sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
-                       ssh->savedhost);
-               s->need_pw = TRUE;
-           }
+                   /*
+                     * Display any instructions, and get the user's
+                     * response(s).
+                    */
+                   {
+                       int ret; /* not live over crReturn */
+                       ret = get_userpass_input(s->cur_prompt, NULL, 0);
+                       while (ret < 0) {
+                           ssh->send_ok = 1;
+                           crWaitUntilV(!pktin);
+                           ret = get_userpass_input(s->cur_prompt, in, inlen);
+                           ssh->send_ok = 0;
+                       }
+                       if (!ret) {
+                           /*
+                            * Failed to get responses. Terminate.
+                            */
+                           free_prompts(s->cur_prompt);
+                           ssh_disconnect(ssh, NULL, "Unable to authenticate",
+                                          SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
+                                          TRUE);
+                           crStopV;
+                       }
+                   }
 
-           if (s->need_pw) {
-               if (ssh_get_line) {
-                   if (!ssh_get_line(s->pwprompt, s->password,
-                                     sizeof(s->password), TRUE)) {
-                       /*
-                        * get_line failed to get a password (for
-                        * example because one was supplied on the
-                        * command line which has already failed to
-                        * work). Terminate.
-                        */
-                       ssh_disconnect(ssh, NULL, "Unable to authenticate",
-                                      SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
-                                      FALSE);
-                       crStopV;
+                   /*
+                    * Send the response(s) to the server.
+                    */
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
+                   ssh2_pkt_adduint32(s->pktout, s->num_prompts);
+                   for (i=0; i < s->num_prompts; i++) {
+                       dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
+                       ssh2_pkt_addstring(s->pktout,
+                                          s->cur_prompt->prompts[i]->result);
+                       end_log_omission(ssh, s->pktout);
                    }
-               } else {
-                   int ret;           /* need not be saved across crReturn */
-                   c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
-                   ssh->send_ok = 1;
+                   ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
+
+                   /*
+                    * Get the next packet in case it's another
+                    * INFO_REQUEST.
+                    */
+                   crWaitUntilV(pktin);
 
-                   setup_userpass_input(ssh, s->password,
-                                        sizeof(s->password), s->echo);
-                   do {
-                       crWaitUntilV(!pktin);
-                       ret = process_userpass_input(ssh, in, inlen);
-                   } while (ret == 0);
-                   if (ret < 0)
-                       cleanup_exit(0);
-                   c_write_str(ssh, "\r\n");
                }
-           }
 
-           if (s->method == AUTH_PUBLICKEY_FILE) {
                /*
-                * We have our passphrase. Now try the actual authentication.
+                * We should have SUCCESS or FAILURE now.
                 */
-               struct ssh2_userkey *key;
-               const char *error = NULL;
-
-               key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
-                                       &error);
-               if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
-                   if (key == SSH2_WRONG_PASSPHRASE) {
-                       c_write_str(ssh, "Wrong passphrase\r\n");
-                       s->tried_pubkey_config = FALSE;
-                   } else {
-                       c_write_str(ssh, "Unable to load private key (");
-                       c_write_str(ssh, error);
-                       c_write_str(ssh, ")\r\n");
-                       s->tried_pubkey_config = TRUE;
-                   }
-                   /* Send a spurious AUTH_NONE to return to the top. */
-                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
-                   ssh2_pkt_addstring(s->pktout, s->username);
-                   ssh2_pkt_addstring(s->pktout, "ssh-connection");    /* service requested */
-                   ssh2_pkt_addstring(s->pktout, "none");      /* method */
-                   ssh2_pkt_send(ssh, s->pktout);
-                   s->type = AUTH_TYPE_NONE;
-               } else {
-                   unsigned char *pkblob, *sigblob, *sigdata;
-                   int pkblob_len, sigblob_len, sigdata_len;
-                    int p;
+               s->gotit = TRUE;
 
-                   /*
-                    * We have loaded the private key and the server
-                    * has announced that it's willing to accept it.
-                    * Hallelujah. Generate a signature and send it.
-                    */
-                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
-                   ssh2_pkt_addstring(s->pktout, s->username);
-                   ssh2_pkt_addstring(s->pktout, "ssh-connection");    /* service requested */
-                   ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
-                   ssh2_pkt_addbool(s->pktout, TRUE);
-                   ssh2_pkt_addstring(s->pktout, key->alg->name);
-                   pkblob = key->alg->public_blob(key->data, &pkblob_len);
-                   ssh2_pkt_addstring_start(s->pktout);
-                   ssh2_pkt_addstring_data(s->pktout, (char *)pkblob, pkblob_len);
+           } else if (s->can_passwd) {
+
+               /*
+                * Plain old password authentication.
+                */
+               int ret; /* not live over crReturn */
+               int changereq_first_time; /* not live over crReturn */
+
+               ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
 
+               s->cur_prompt = new_prompts(ssh->frontend);
+               s->cur_prompt->to_server = TRUE;
+               s->cur_prompt->name = dupstr("SSH password");
+               add_prompt(s->cur_prompt, dupprintf("%.90s@%.90s's password: ",
+                                                   s->username,
+                                                   ssh->savedhost),
+                          FALSE, SSH_MAX_PASSWORD_LEN);
+
+               ret = get_userpass_input(s->cur_prompt, NULL, 0);
+               while (ret < 0) {
+                   ssh->send_ok = 1;
+                   crWaitUntilV(!pktin);
+                   ret = get_userpass_input(s->cur_prompt, in, inlen);
+                   ssh->send_ok = 0;
+               }
+               if (!ret) {
                    /*
-                    * The data to be signed is:
-                    *
-                    *   string  session-id
-                    *
-                    * followed by everything so far placed in the
-                    * outgoing packet.
+                    * Failed to get responses. Terminate.
                     */
-                   sigdata_len = s->pktout->length - 5 + 4 +
-                       ssh->v2_session_id_len;
-                    if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
-                        sigdata_len -= 4;
-                   sigdata = snewn(sigdata_len, unsigned char);
-                    p = 0;
-                    if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
-                        PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
-                        p += 4;
-                    }
-                   memcpy(sigdata+p, ssh->v2_session_id,
-                          ssh->v2_session_id_len);
-                   p += ssh->v2_session_id_len;
-                   memcpy(sigdata+p, s->pktout->data + 5,
-                          s->pktout->length - 5);
-                    p += s->pktout->length - 5;
-                    assert(p == sigdata_len);
-                   sigblob = key->alg->sign(key->data, (char *)sigdata,
-                                            sigdata_len, &sigblob_len);
-                   ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
-                                    sigblob, sigblob_len);
-                   sfree(pkblob);
-                   sfree(sigblob);
-                   sfree(sigdata);
-
-                   ssh2_pkt_send(ssh, s->pktout);
-                   s->type = AUTH_TYPE_PUBLICKEY;
-                   key->alg->freekey(key->data);
+                   free_prompts(s->cur_prompt);
+                   ssh_disconnect(ssh, NULL, "Unable to authenticate",
+                                  SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
+                                  TRUE);
+                   crStopV;
                }
-           } else if (s->method == AUTH_PASSWORD) {
                /*
+                * Squirrel away the password. (We may need it later if
+                * asked to change it.)
+                */
+               s->password = dupstr(s->cur_prompt->prompts[0]->result);
+               free_prompts(s->cur_prompt);
+
+               /*
+                * Send the password packet.
+                *
                 * We pad out the password packet to 256 bytes to make
                 * it harder for an attacker to find the length of the
                 * user's password.
@@ -7251,56 +8317,203 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                 * people who find out how long their password is!
                 */
                s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
-               s->pktout->forcepad = 256;
                ssh2_pkt_addstring(s->pktout, s->username);
-               ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                                       /* service requested */
                ssh2_pkt_addstring(s->pktout, "password");
                ssh2_pkt_addbool(s->pktout, FALSE);
                dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
                ssh2_pkt_addstring(s->pktout, s->password);
-               memset(s->password, 0, sizeof(s->password));
                end_log_omission(ssh, s->pktout);
-               ssh2_pkt_send(ssh, s->pktout);
+               ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
                logevent("Sent password");
                s->type = AUTH_TYPE_PASSWORD;
-           } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
-               if (s->curr_prompt == 0) {
-                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
-                   s->pktout->forcepad = 256;
-                   ssh2_pkt_adduint32(s->pktout, s->num_prompts);
-               }
-               if (s->need_pw) {      /* only add pw if we just got one! */
+
+               /*
+                * Wait for next packet, in case it's a password change
+                * request.
+                */
+               crWaitUntilV(pktin);
+               changereq_first_time = TRUE;
+
+               while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
+
+                   /* 
+                    * We're being asked for a new password
+                    * (perhaps not for the first time).
+                    * Loop until the server accepts it.
+                    */
+
+                   int got_new = FALSE; /* not live over crReturn */
+                   char *prompt;   /* not live over crReturn */
+                   int prompt_len; /* not live over crReturn */
+                   
+                   {
+                       char *msg;
+                       if (changereq_first_time)
+                           msg = "Server requested password change";
+                       else
+                           msg = "Server rejected new password";
+                       logevent(msg);
+                       c_write_str(ssh, msg);
+                       c_write_str(ssh, "\r\n");
+                   }
+
+                   ssh_pkt_getstring(pktin, &prompt, &prompt_len);
+
+                   s->cur_prompt = new_prompts(ssh->frontend);
+                   s->cur_prompt->to_server = TRUE;
+                   s->cur_prompt->name = dupstr("New SSH password");
+                   s->cur_prompt->instruction =
+                       dupprintf("%.*s", prompt_len, prompt);
+                   s->cur_prompt->instr_reqd = TRUE;
+                   /*
+                    * There's no explicit requirement in the protocol
+                    * for the "old" passwords in the original and
+                    * password-change messages to be the same, and
+                    * apparently some Cisco kit supports password change
+                    * by the user entering a blank password originally
+                    * and the real password subsequently, so,
+                    * reluctantly, we prompt for the old password again.
+                    *
+                    * (On the other hand, some servers don't even bother
+                    * to check this field.)
+                    */
+                   add_prompt(s->cur_prompt,
+                              dupstr("Current password (blank for previously entered password): "),
+                              FALSE, SSH_MAX_PASSWORD_LEN);
+                   add_prompt(s->cur_prompt, dupstr("Enter new password: "),
+                              FALSE, SSH_MAX_PASSWORD_LEN);
+                   add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
+                              FALSE, SSH_MAX_PASSWORD_LEN);
+
+                   /*
+                    * Loop until the user manages to enter the same
+                    * password twice.
+                    */
+                   while (!got_new) {
+
+                       ret = get_userpass_input(s->cur_prompt, NULL, 0);
+                       while (ret < 0) {
+                           ssh->send_ok = 1;
+                           crWaitUntilV(!pktin);
+                           ret = get_userpass_input(s->cur_prompt, in, inlen);
+                           ssh->send_ok = 0;
+                       }
+                       if (!ret) {
+                           /*
+                            * Failed to get responses. Terminate.
+                            */
+                           /* burn the evidence */
+                           free_prompts(s->cur_prompt);
+                           memset(s->password, 0, strlen(s->password));
+                           sfree(s->password);
+                           ssh_disconnect(ssh, NULL, "Unable to authenticate",
+                                          SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
+                                          TRUE);
+                           crStopV;
+                       }
+
+                       /*
+                        * If the user specified a new original password
+                        * (IYSWIM), overwrite any previously specified
+                        * one.
+                        * (A side effect is that the user doesn't have to
+                        * re-enter it if they louse up the new password.)
+                        */
+                       if (s->cur_prompt->prompts[0]->result[0]) {
+                           memset(s->password, 0, strlen(s->password));
+                               /* burn the evidence */
+                           sfree(s->password);
+                           s->password =
+                               dupstr(s->cur_prompt->prompts[0]->result);
+                       }
+
+                       /*
+                        * Check the two new passwords match.
+                        */
+                       got_new = (strcmp(s->cur_prompt->prompts[1]->result,
+                                         s->cur_prompt->prompts[2]->result)
+                                  == 0);
+                       if (!got_new)
+                           /* They don't. Silly user. */
+                           c_write_str(ssh, "Passwords do not match\r\n");
+
+                   }
+
+                   /*
+                    * Send the new password (along with the old one).
+                    * (see above for padding rationale)
+                    */
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                   ssh2_pkt_addstring(s->pktout, s->username);
+                   ssh2_pkt_addstring(s->pktout, "ssh-connection");
+                                                       /* service requested */
+                   ssh2_pkt_addstring(s->pktout, "password");
+                   ssh2_pkt_addbool(s->pktout, TRUE);
                    dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
                    ssh2_pkt_addstring(s->pktout, s->password);
-                   memset(s->password, 0, sizeof(s->password));
+                   ssh2_pkt_addstring(s->pktout,
+                                      s->cur_prompt->prompts[1]->result);
+                   free_prompts(s->cur_prompt);
                    end_log_omission(ssh, s->pktout);
-                   s->curr_prompt++;
-               }
-               if (s->curr_prompt >= s->num_prompts) {
-                   ssh2_pkt_send(ssh, s->pktout);
-               } else {
+                   ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
+                   logevent("Sent new password");
+                   
                    /*
-                    * If there are prompts remaining, we set
-                    * `gotit' so that we won't attempt to get
-                    * another packet. Then we go back round the
-                    * loop and will end up retrieving another
-                    * prompt out of the existing packet. Funky or
-                    * what?
+                    * Now see what the server has to say about it.
+                    * (If it's CHANGEREQ again, it's not happy with the
+                    * new password.)
                     */
-                   s->gotit = TRUE;
+                   crWaitUntilV(pktin);
+                   changereq_first_time = FALSE;
+
                }
-               s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
+
+               /*
+                * We need to reexamine the current pktin at the top
+                * of the loop. Either:
+                *  - we weren't asked to change password at all, in
+                *    which case it's a SUCCESS or FAILURE with the
+                *    usual meaning
+                *  - we sent a new password, and the server was
+                *    either OK with it (SUCCESS or FAILURE w/partial
+                *    success) or unhappy with the _old_ password
+                *    (FAILURE w/o partial success)
+                * In any of these cases, we go back to the top of
+                * the loop and start again.
+                */
+               s->gotit = TRUE;
+
+               /*
+                * We don't need the old password any more, in any
+                * case. Burn the evidence.
+                */
+               memset(s->password, 0, strlen(s->password));
+               sfree(s->password);
+
            } else {
+
                ssh_disconnect(ssh, NULL,
                               "No supported authentication methods available",
                               SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
                               FALSE);
                crStopV;
+
            }
+
        }
     }
     ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
 
+    /* Clear up various bits and pieces from authentication. */
+    if (s->publickey_blob) {
+       sfree(s->publickey_blob);
+       sfree(s->publickey_comment);
+    }
+    if (s->agent_response)
+       sfree(s->agent_response);
+
     /*
      * Now the connection protocol has started, one way or another.
      */
@@ -7319,14 +8532,61 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     /*
      * Create the main session channel.
      */
-    if (!ssh->cfg.ssh_no_shell) {
+    if (ssh->cfg.ssh_no_shell) {
+       ssh->mainchan = NULL;
+    } else if (*ssh->cfg.ssh_nc_host) {
+       /*
+        * Just start a direct-tcpip channel and use it as the main
+        * channel.
+        */
+       ssh->mainchan = snew(struct ssh_channel);
+       ssh->mainchan->ssh = ssh;
+       ssh2_channel_init(ssh->mainchan);
+       logeventf(ssh,
+                 "Opening direct-tcpip channel to %s:%d in place of session",
+                 ssh->cfg.ssh_nc_host, ssh->cfg.ssh_nc_port);
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
+       ssh2_pkt_addstring(s->pktout, "direct-tcpip");
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */
+       ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT);      /* our max pkt size */
+       ssh2_pkt_addstring(s->pktout, ssh->cfg.ssh_nc_host);
+       ssh2_pkt_adduint32(s->pktout, ssh->cfg.ssh_nc_port);
+       /*
+        * There's nothing meaningful to put in the originator
+        * fields, but some servers insist on syntactically correct
+        * information.
+        */
+       ssh2_pkt_addstring(s->pktout, "0.0.0.0");
+       ssh2_pkt_adduint32(s->pktout, 0);
+       ssh2_pkt_send(ssh, s->pktout);
+
+       crWaitUntilV(pktin);
+       if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
+           bombout(("Server refused to open a direct-tcpip channel"));
+           crStopV;
+           /* FIXME: error data comes back in FAILURE packet */
+       }
+       if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
+           bombout(("Server's channel confirmation cited wrong channel"));
+           crStopV;
+       }
+       ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
+       ssh->mainchan->halfopen = FALSE;
+       ssh->mainchan->type = CHAN_MAINSESSION;
+       ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
+       ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
+       add234(ssh->channels, ssh->mainchan);
+       update_specials_menu(ssh->frontend);
+       logevent("Opened direct-tcpip channel");
+       ssh->ncmode = TRUE;
+    } else {
        ssh->mainchan = snew(struct ssh_channel);
        ssh->mainchan->ssh = ssh;
-       ssh->mainchan->localid = alloc_channel_id(ssh);
+       ssh2_channel_init(ssh->mainchan);
        s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
        ssh2_pkt_addstring(s->pktout, "session");
        ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid);
-       ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
        ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */
        ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT);    /* our max pkt size */
        ssh2_pkt_send(ssh, s->pktout);
@@ -7343,15 +8603,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
        ssh->mainchan->halfopen = FALSE;
        ssh->mainchan->type = CHAN_MAINSESSION;
-       ssh->mainchan->closes = 0;
        ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
        ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
-       bufchain_init(&ssh->mainchan->v.v2.outbuffer);
        add234(ssh->channels, ssh->mainchan);
        update_specials_menu(ssh->frontend);
        logevent("Opened channel for session");
-    } else
-       ssh->mainchan = NULL;
+       ssh->ncmode = FALSE;
+    }
 
     /*
      * Now we have a channel, make dispatch table entries for
@@ -7371,21 +8629,33 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
        ssh2_msg_channel_open;
 
+    if (ssh->mainchan && ssh->cfg.ssh_simple) {
+       /*
+        * This message indicates to the server that we promise
+        * not to try to run any other channel in parallel with
+        * this one, so it's safe for it to advertise a very large
+        * window and leave the flow control to TCP.
+        */
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
+       ssh2_pkt_addstring(s->pktout, "simple@putty.projects.tartarus.org");
+       ssh2_pkt_addbool(s->pktout, 0); /* no reply */
+       ssh2_pkt_send(ssh, s->pktout);
+    }
+
     /*
      * Potentially enable X11 forwarding.
      */
-    if (ssh->mainchan && ssh->cfg.x11_forward) {
-       char proto[20], data[64];
+    if (ssh->mainchan && !ssh->ncmode && ssh->cfg.x11_forward &&
+       (ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                         ssh->cfg.x11_auth, &ssh->cfg))) {
        logevent("Requesting X11 forwarding");
-       ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
-                                      data, sizeof(data), ssh->cfg.x11_auth);
-        x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
        s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
        ssh2_pkt_addstring(s->pktout, "x11-req");
        ssh2_pkt_addbool(s->pktout, 1);        /* want reply */
        ssh2_pkt_addbool(s->pktout, 0);        /* many connections */
-       ssh2_pkt_addstring(s->pktout, proto);
+       ssh2_pkt_addstring(s->pktout, ssh->x11disp->remoteauthprotoname);
        /*
         * Note that while we blank the X authentication data here, we don't
         * take any special action to blank the start of an X11 channel,
@@ -7394,9 +8664,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
         * cookie into the log.
         */
        dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
-       ssh2_pkt_addstring(s->pktout, data);
+       ssh2_pkt_addstring(s->pktout, ssh->x11disp->remoteauthdatastring);
        end_log_omission(ssh, s->pktout);
-       ssh2_pkt_adduint32(s->pktout, x11_get_screen_number(ssh->cfg.x11_display));
+       ssh2_pkt_adduint32(s->pktout, ssh->x11disp->screennum);
        ssh2_pkt_send(ssh, s->pktout);
 
        crWaitUntilV(pktin);
@@ -7422,7 +8692,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     /*
      * Potentially enable agent forwarding.
      */
-    if (ssh->mainchan && ssh->cfg.agentfwd && agent_exists()) {
+    if (ssh->mainchan && !ssh->ncmode && ssh->cfg.agentfwd && agent_exists()) {
        logevent("Requesting OpenSSH-style agent forwarding");
        s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
@@ -7448,7 +8718,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     /*
      * Now allocate a pty for the session.
      */
-    if (ssh->mainchan && !ssh->cfg.nopty) {
+    if (ssh->mainchan && !ssh->ncmode && !ssh->cfg.nopty) {
        /* Unpick the terminal-speed string. */
        /* XXX perhaps we should allow no speeds to be sent. */
         ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
@@ -7498,7 +8768,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
      * Simplest thing here is to send all the requests at once, and
      * then wait for a whole bunch of successes or failures.
      */
-    if (ssh->mainchan && *ssh->cfg.environmt) {
+    if (ssh->mainchan && !ssh->ncmode && *ssh->cfg.environmt) {
        char *e = ssh->cfg.environmt;
        char *var, *varend, *val;
 
@@ -7563,7 +8833,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
      * this twice if the config data has provided a second choice
      * of command.
      */
-    if (ssh->mainchan) while (1) {
+    if (ssh->mainchan && !ssh->ncmode) while (1) {
        int subsys;
        char *cmd;
 
@@ -7626,6 +8896,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        ssh_special(ssh, TS_EOF);
 
     /*
+     * All the initial channel requests are done, so install the default
+     * failure handler.
+     */
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_success;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_failure;
+
+    /*
      * Transfer data!
      */
     if (ssh->ldisc)
@@ -7673,7 +8950,7 @@ static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
 {
     /* log reason code in disconnect message */
     char *buf, *msg;
-    int nowlen, reason, msglen;
+    int reason, msglen;
 
     reason = ssh_pkt_getuint32(pktin);
     ssh_pkt_getstring(pktin, &msg, &msglen);
@@ -7687,14 +8964,14 @@ static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
     }
     logevent(buf);
     sfree(buf);
-    buf = dupprintf("Disconnection message text: %n%.*s",
-                   &nowlen, msglen, msg);
+    buf = dupprintf("Disconnection message text: %.*s",
+                   msglen, msg);
     logevent(buf);
-    bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
+    bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
             reason,
             (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
             ssh2_disconnect_reasons[reason] : "unknown",
-            buf+nowlen));
+            msglen, msg));
     sfree(buf);
 }
 
@@ -7878,8 +9155,9 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->deferred_len = 0;
     ssh->deferred_size = 0;
     ssh->fallback_cmd = 0;
-    ssh->pkt_ctx = 0;
-    ssh->x11auth = NULL;
+    ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
+    ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
+    ssh->x11disp = NULL;
     ssh->v1_compressing = FALSE;
     ssh->v2_outgoing_sequence = 0;
     ssh->ssh1_rdpkt_crstate = 0;
@@ -7925,7 +9203,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->send_ok = 0;
     ssh->editing = 0;
     ssh->echoing = 0;
-    ssh->v1_throttle_count = 0;
+    ssh->conn_throttle_count = 0;
     ssh->overall_bufsize = 0;
     ssh->fallback_cmd = 0;
 
@@ -8017,14 +9295,15 @@ static void ssh_free(void *handle)
        ssh->rportfwds = NULL;
     }
     sfree(ssh->deferred_send_data);
-    if (ssh->x11auth)
-       x11_free_auth(ssh->x11auth);
+    if (ssh->x11disp)
+       x11_free_display(ssh->x11disp);
     sfree(ssh->do_ssh_init_state);
     sfree(ssh->do_ssh1_login_state);
     sfree(ssh->do_ssh2_transport_state);
     sfree(ssh->do_ssh2_authconn_state);
     sfree(ssh->v_c);
     sfree(ssh->v_s);
+    sfree(ssh->fullhostname);
     if (ssh->crcda_ctx) {
        crcda_free_context(ssh->crcda_ctx);
        ssh->crcda_ctx = NULL;
@@ -8195,14 +9474,16 @@ static const struct telnet_special *ssh_get_specials(void *handle)
     static const struct telnet_special ssh1_ignore_special[] = {
        {"IGNORE message", TS_NOP}
     };
-    static const struct telnet_special ssh2_transport_specials[] = {
+    static const struct telnet_special ssh2_ignore_special[] = {
        {"IGNORE message", TS_NOP},
+    };
+    static const struct telnet_special ssh2_rekey_special[] = {
        {"Repeat key exchange", TS_REKEY},
     };
     static const struct telnet_special ssh2_session_specials[] = {
        {NULL, TS_SEP},
        {"Break", TS_BRK},
-       /* These are the signal names defined by draft-ietf-secsh-connect-23.
+       /* These are the signal names defined by RFC 4254.
         * They include all the ISO C signals, but are a subset of the POSIX
         * required signals. */
        {"SIGINT (Interrupt)", TS_SIGINT},
@@ -8221,7 +9502,8 @@ static const struct telnet_special *ssh_get_specials(void *handle)
        {NULL, TS_EXITMENU}
     };
     /* XXX review this length for any changes: */
-    static struct telnet_special ssh_specials[lenof(ssh2_transport_specials) +
+    static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
+                                             lenof(ssh2_rekey_special) +
                                              lenof(ssh2_session_specials) +
                                              lenof(specials_end)];
     Ssh ssh = (Ssh) handle;
@@ -8240,7 +9522,10 @@ static const struct telnet_special *ssh_get_specials(void *handle)
        if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
            ADD_SPECIALS(ssh1_ignore_special);
     } else if (ssh->version == 2) {
-       ADD_SPECIALS(ssh2_transport_specials);
+       if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
+           ADD_SPECIALS(ssh2_ignore_special);
+       if (!(ssh->remote_bugs & BUG_SSH2_REKEY))
+           ADD_SPECIALS(ssh2_rekey_special);
        if (ssh->mainchan)
            ADD_SPECIALS(ssh2_session_specials);
     } /* else we're not ready yet */
@@ -8290,9 +9575,11 @@ static void ssh_special(void *handle, Telnet_Special code)
            if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
                send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
        } else {
-           pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
-           ssh2_pkt_addstring_start(pktout);
-           ssh2_pkt_send_noqueue(ssh, pktout);
+           if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
+               pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
+               ssh2_pkt_addstring_start(pktout);
+               ssh2_pkt_send_noqueue(ssh, pktout);
+           }
        }
     } else if (code == TS_REKEY) {
        if (!ssh->kex_in_progress && ssh->version == 2) {
@@ -8351,17 +9638,13 @@ void *new_sock_channel(void *handle, Socket s)
     Ssh ssh = (Ssh) handle;
     struct ssh_channel *c;
     c = snew(struct ssh_channel);
-    c->ssh = ssh;
 
-    if (c) {
-       c->halfopen = TRUE;
-       c->localid = alloc_channel_id(ssh);
-       c->closes = 0;
-       c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
-       c->u.pfd.s = s;
-       bufchain_init(&c->v.v2.outbuffer);
-       add234(ssh->channels, c);
-    }
+    c->ssh = ssh;
+    ssh2_channel_init(c);
+    c->halfopen = TRUE;
+    c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
+    c->u.pfd.s = s;
+    add234(ssh->channels, c);
     return c;
 }
 
@@ -8372,14 +9655,27 @@ void *new_sock_channel(void *handle, Socket s)
 static void ssh_unthrottle(void *handle, int bufsize)
 {
     Ssh ssh = (Ssh) handle;
+    int buflimit;
+
     if (ssh->version == 1) {
        if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
            ssh->v1_stdout_throttling = 0;
-           ssh1_throttle(ssh, -1);
+           ssh_throttle_conn(ssh, -1);
        }
     } else {
-       if (ssh->mainchan && ssh->mainchan->closes == 0)
-           ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
+       if (ssh->mainchan) {
+           ssh2_set_window(ssh->mainchan,
+                           bufsize < ssh->mainchan->v.v2.locmaxwin ?
+                           ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
+           if (ssh->cfg.ssh_simple)
+               buflimit = 0;
+           else
+               buflimit = ssh->mainchan->v.v2.locmaxwin;
+           if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
+               ssh->mainchan->throttling_conn = 0;
+               ssh_throttle_conn(ssh, -1);
+           }
+       }
     }
 }
 
@@ -8402,7 +9698,6 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
        ssh2_pkt_addstring(pktout, "direct-tcpip");
        ssh2_pkt_adduint32(pktout, c->localid);
-       c->v.v2.locwindow = OUR_V2_WINSIZE;
        ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
        ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT);      /* our max pkt size */
        ssh2_pkt_addstring(pktout, hostname);
@@ -8412,17 +9707,20 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
         * too much hassle to keep track, and partly I'm not
         * convinced the server should be told details like that
         * about my local network configuration.
+        * The "originator IP address" is syntactically a numeric
+        * IP address, and some servers (e.g., Tectia) get upset
+        * if it doesn't match this syntax.
         */
-       ssh2_pkt_addstring(pktout, "client-side-connection");
+       ssh2_pkt_addstring(pktout, "0.0.0.0");
        ssh2_pkt_adduint32(pktout, 0);
        ssh2_pkt_send(ssh, pktout);
     }
 }
 
-static Socket ssh_socket(void *handle)
+static int ssh_connected(void *handle)
 {
     Ssh ssh = (Ssh) handle;
-    return ssh->s;
+    return ssh->s != NULL;
 }
 
 static int ssh_sendok(void *handle)
@@ -8459,7 +9757,7 @@ static int ssh_return_exitcode(void *handle)
     if (ssh->s != NULL)
         return -1;
     else
-        return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
+        return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
 }
 
 /*
@@ -8492,7 +9790,7 @@ Backend ssh_backend = {
     ssh_size,
     ssh_special,
     ssh_get_specials,
-    ssh_socket,
+    ssh_connected,
     ssh_return_exitcode,
     ssh_sendok,
     ssh_ldisc,
@@ -8500,5 +9798,7 @@ Backend ssh_backend = {
     ssh_provide_logctx,
     ssh_unthrottle,
     ssh_cfg_info,
+    "ssh",
+    PROT_SSH,
     22
 };