Revamp of the local X11 connection code. We now parse X display
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index 63aecbc..d30626d 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -12,6 +12,7 @@
 #include "putty.h"
 #include "tree234.h"
 #include "ssh.h"
+#include "sshgss.h"
 
 #ifndef FALSE
 #define FALSE 0
 #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
@@ -127,6 +134,7 @@ typedef enum {
     SSH2_PKTCTX_NOAUTH,
     SSH2_PKTCTX_PUBLICKEY,
     SSH2_PKTCTX_PASSWORD,
+    SSH2_PKTCTX_GSSAPI,
     SSH2_PKTCTX_KBDINTER
 } Pkt_ACtx;
 
@@ -183,6 +191,7 @@ 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
 
 /*
  * Codes for terminal modes.
@@ -338,6 +347,12 @@ static char *ssh1_pkt_type(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);
@@ -809,7 +824,7 @@ struct ssh_tag {
     Pkt_KCtx pkt_kctx;
     Pkt_ACtx pkt_actx;
 
-    void *x11auth;
+    struct X11Display *x11disp;
 
     int version;
     int conn_throttle_count;
@@ -895,6 +910,11 @@ 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)
@@ -1267,7 +1287,7 @@ 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);
@@ -1427,7 +1447,7 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
                   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);
@@ -1452,7 +1472,7 @@ 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;
 
@@ -1492,7 +1512,8 @@ static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
 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);
+       log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
+                  0, NULL, NULL);
     return sk_write(ssh->s, (char *)data, len);
 }
 
@@ -1775,7 +1796,7 @@ static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
        log_packet(ssh->logctx, PKT_OUTGOING, 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;
 
@@ -2391,6 +2412,17 @@ 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");
+    }
 }
 
 /*
@@ -2633,7 +2665,7 @@ 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);
+                  0, NULL, NULL);
 
     crBegin(ssh->ssh_gotdata_crstate);
 
@@ -2826,12 +2858,30 @@ 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;
 
-    if (port < 0)
-       port = 22;                     /* default ssh port */
-    ssh->savedport = port;
+       ssh->savedhost = dupstr(ssh->cfg.loghost);
+       ssh->savedport = 22;           /* default ssh 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.
@@ -2845,6 +2895,7 @@ 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.
@@ -2869,6 +2920,14 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
        ssh_send_verstring(ssh, NULL);
     }
 
+    /*
+     * loghost, if configured, overrides realhost.
+     */
+    if (*ssh->cfg.loghost) {
+       sfree(*realhost);
+       *realhost = dupstr(ssh->cfg.loghost);
+    }
+
     return NULL;
 }
 
@@ -4519,8 +4578,8 @@ 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,
@@ -4855,11 +4914,9 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
     }
 
     if (ssh->cfg.x11_forward) {
-       char proto[20], data[64];
        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);
+       ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                        ssh->cfg.x11_auth, &ssh->cfg);
        /*
         * 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,
@@ -4869,14 +4926,19 @@ 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;
@@ -6236,6 +6298,15 @@ static void ssh2_set_window(struct ssh_channel *c, int 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.
@@ -6677,7 +6748,7 @@ 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. */
            {
@@ -6720,7 +6791,7 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *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);
@@ -6871,9 +6942,8 @@ 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 (x11_init(&c->u.x11.s, ssh->x11disp, c,
+                         addrstr, peerport, &ssh->cfg) != NULL) {
            error = "Unable to open an X11 connection";
        } else {
            logevent("Opening X11 forward connection succeeded");
@@ -6996,12 +7066,15 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                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, done_agent;
+       int can_gssapi;
+       int tried_gssapi;
        int kbd_inter_refused;
        int we_are_in;
        prompts_t *cur_prompt;
@@ -7025,6 +7098,11 @@ 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;
+       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;
     };
     crState(do_ssh2_authconn_state);
 
@@ -7032,6 +7110,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
 
     s->done_service_req = FALSE;
     s->we_are_in = FALSE;
+    s->tried_gssapi = FALSE;
+
     if (!ssh->cfg.ssh_no_userauth) {
        /*
         * Request userauth protocol, and await a response to it.
@@ -7319,7 +7399,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                break;
            }
 
-           if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
+           if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
                bombout(("Strange packet received during authentication: "
                         "type %d", pktin->type));
                crStopV;
@@ -7390,6 +7470,11 @@ 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              
+               s->can_gssapi = ssh->cfg.try_gssapi_auth &&
+                 in_commasep_string("gssapi-with-mic", methods, methlen) &&
+                 ssh_gss_init();
+#endif
            }
 
            ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
@@ -7718,6 +7803,157 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    key->alg->freekey(key->data);
                }
 
+#ifndef NO_GSSAPI
+           } else if (s->can_gssapi && !s->tried_gssapi) {
+
+               /* GSSAPI Authentication */
+
+               int micoffset;
+               Ssh_gss_buf mic;
+               s->type = AUTH_TYPE_GSSAPI;
+               s->tried_gssapi = TRUE;
+               s->gotit = TRUE;
+               ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
+
+               /* 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 */
+               ssh_gss_indicate_mech(&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.len + 2);
+               ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
+
+               /* length of OID */
+               ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.len);
+
+               ssh_pkt_adddata(s->pktout, s->gss_buf.data, s->gss_buf.len);
+               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,&s->gss_rcvtok.data,&s->gss_rcvtok.len);
+               if (s->gss_rcvtok.len != s->gss_buf.len + 2 ||
+                   s->gss_rcvtok.data[0] != SSH2_GSS_OIDTYPE ||
+                   s->gss_rcvtok.data[1] != s->gss_buf.len ||
+                   memcmp(s->gss_rcvtok.data+2,s->gss_buf.data,s->gss_buf.len) ) {
+                   logevent("GSSAPI authentication - wrong response from server");
+                   continue;
+               }
+
+               /* now start running */
+               s->gss_stat = ssh_gss_import_name(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 = ssh_gss_acquire_cred(&s->gss_ctx);
+
+               if (s->gss_stat != SSH_GSS_OK) {
+                   logevent("GSSAPI authentication failed to get credentials");
+                   ssh_gss_release_name(&s->gss_srv_name);
+                   continue;
+               }
+
+               /* initial tokens are empty */
+               s->gss_rcvtok.len = s->gss_sndtok.len = 0;
+               s->gss_rcvtok.data = s->gss_sndtok.data = NULL;
+
+               /* now enter the loop */
+               do {
+                   s->gss_stat = ssh_gss_init_sec_context(&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 (ssh_gss_display_status(s->gss_ctx,&s->gss_buf) == SSH_GSS_OK) {
+                           logevent(s->gss_buf.data);
+                           sfree(s->gss_buf.data);
+                       }
+
+                       break;
+                   }
+                   logevent("GSSAPI authentication initialised");
+
+                   /* Client and server now exchange tokens until GSSAPI
+                    * no longer says CONTINUE_NEEDED */
+
+                   if (s->gss_sndtok.len != 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.data,s->gss_sndtok.len);
+                       ssh2_pkt_send(ssh, s->pktout);
+                       ssh_gss_free_tok(&s->gss_sndtok);
+                   }
+
+                   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,&s->gss_rcvtok.data,&s->gss_rcvtok.len);
+                   }
+               } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
+
+               if (s->gss_stat != SSH_GSS_OK) {
+                   ssh_gss_release_name(&s->gss_srv_name);
+                   ssh_gss_release_cred(&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.data = (char *)s->pktout->data + micoffset;
+               s->gss_buf.len = s->pktout->length - micoffset;
+
+               ssh_gss_get_mic(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.data, mic.len);
+               ssh2_pkt_send(ssh, s->pktout);
+               ssh_gss_free_mic(&mic);
+
+               s->gotit = FALSE;
+
+               ssh_gss_release_name(&s->gss_srv_name);
+               ssh_gss_release_cred(&s->gss_ctx);
+               continue;
+#endif
            } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
 
                /*
@@ -7789,7 +8025,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    s->cur_prompt->instr_reqd = TRUE;
 
                    /*
-                    * Get the prompts from the packet.
+                    * Get any prompt(s) from the packet.
                     */
                    s->num_prompts = ssh_pkt_getuint32(pktin);
                    for (i = 0; i < s->num_prompts; i++) {
@@ -7811,9 +8047,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    }
 
                    /*
-                    * Get the user's responses.
+                     * Display any instructions, and get the user's
+                     * response(s).
                     */
-                   if (s->num_prompts) {
+                   {
                        int ret; /* not live over crReturn */
                        ret = get_userpass_input(s->cur_prompt, NULL, 0);
                        while (ret < 0) {
@@ -7835,7 +8072,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    }
 
                    /*
-                    * Send the responses to the server.
+                    * 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);
@@ -8244,17 +8481,15 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
      * Potentially enable X11 forwarding.
      */
     if (ssh->mainchan && !ssh->ncmode && ssh->cfg.x11_forward) {
-       char proto[20], data[64];
        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);
+       ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                        ssh->cfg.x11_auth, &ssh->cfg);
        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,
@@ -8263,9 +8498,9 @@ 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);
@@ -8549,7 +8784,7 @@ 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);
@@ -8563,14 +8798,14 @@ 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);
 }
 
@@ -8756,7 +8991,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->fallback_cmd = 0;
     ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
     ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
-    ssh->x11auth = NULL;
+    ssh->x11disp = NULL;
     ssh->v1_compressing = FALSE;
     ssh->v2_outgoing_sequence = 0;
     ssh->ssh1_rdpkt_crstate = 0;
@@ -8894,14 +9129,15 @@ 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;
@@ -9079,7 +9315,7 @@ static const struct telnet_special *ssh_get_specials(void *handle)
     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},