Add the ability to close sessions. This adds *_free() functions to most
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index e60e031..1d9b1ed 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -166,7 +166,7 @@ static const char *const ssh2_disconnect_reasons[] = {
 
 #define translate(x) if (type == x) return #x
 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
-char *ssh1_pkt_type(int type)
+static char *ssh1_pkt_type(int type)
 {
     translate(SSH1_MSG_DISCONNECT);
     translate(SSH1_SMSG_PUBLIC_KEY);
@@ -211,7 +211,7 @@ char *ssh1_pkt_type(int type)
     translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
     return "unknown";
 }
-char *ssh2_pkt_type(int pkt_ctx, int type)
+static char *ssh2_pkt_type(int pkt_ctx, int type)
 {
     translate(SSH2_MSG_DISCONNECT);
     translate(SSH2_MSG_IGNORE);
@@ -291,22 +291,6 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
 
 typedef struct ssh_tag *Ssh;
 
-extern char *x11_init(Socket *, char *, void *, void *);
-extern void x11_close(Socket);
-extern int x11_send(Socket, char *, int);
-extern void *x11_invent_auth(char *, int, char *, int);
-extern void x11_unthrottle(Socket s);
-extern void x11_override_throttle(Socket s, int enable);
-
-extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
-extern char *pfd_addforward(char *desthost, int destport, int port,
-                           void *backhandle);
-extern void pfd_close(Socket s);
-extern int pfd_send(Socket s, char *data, int len);
-extern void pfd_confirm(Socket s);
-extern void pfd_unthrottle(Socket s);
-extern void pfd_override_throttle(Socket s, int enable);
-
 static void ssh2_pkt_init(Ssh, int pkt_type);
 static void ssh2_pkt_addbool(Ssh, unsigned char value);
 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
@@ -314,7 +298,7 @@ static void ssh2_pkt_addstring_start(Ssh);
 static void ssh2_pkt_addstring_str(Ssh, char *data);
 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
 static void ssh2_pkt_addstring(Ssh, char *data);
-static char *ssh2_mpint_fmt(Bignum b, int *len);
+static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
 static void ssh2_pkt_addmp(Ssh, Bignum b);
 static int ssh2_pkt_construct(Ssh);
 static void ssh2_pkt_send(Ssh);
@@ -636,22 +620,29 @@ struct ssh_tag {
 
     void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
     int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
+
+    /*
+     * We maintain a full _copy_ of a Config structure here, not
+     * merely a pointer to it. That way, when we're passed a new
+     * one for reconfiguration, we can check the differences and
+     * potentially reconfigure port forwardings etc in mid-session.
+     */
+    Config cfg;
 };
 
-#define logevent(s) { logevent(ssh->frontend, s); \
-                      if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
-                      { fprintf(stderr, "%s\n", s); fflush(stderr); } }
+#define logevent(s) logevent(ssh->frontend, s)
 
 /* logevent, only printf-formatted. */
-void logeventf(Ssh ssh, char *fmt, ...)
+static void logeventf(Ssh ssh, char *fmt, ...)
 {
     va_list ap;
-    char stuff[200];
+    char *buf;
 
     va_start(ap, fmt);
-    vsprintf(stuff, fmt, ap);
+    buf = dupvprintf(fmt, ap);
     va_end(ap);
-    logevent(stuff);
+    logevent(buf);
+    sfree(buf);
 }
 
 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
@@ -1049,30 +1040,29 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
       case SSH2_MSG_DISCONNECT:
         {
             /* log reason code in disconnect message */
-            char buf[256];
+            char *buf;
+           int nowlen;
             int reason = GET_32BIT(ssh->pktin.data + 6);
             unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
-            unsigned nowlen;
+
             if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
-                sprintf(buf, "Received disconnect message (%s)",
-                        ssh2_disconnect_reasons[reason]);
+                buf = dupprintf("Received disconnect message (%s)",
+                               ssh2_disconnect_reasons[reason]);
             } else {
-                sprintf(buf, "Received disconnect message (unknown type %d)",
-                        reason);
+                buf = dupprintf("Received disconnect message (unknown"
+                               " type %d)", reason);
             }
             logevent(buf);
-            strcpy(buf, "Disconnection message text: ");
-            nowlen = strlen(buf);
-            if (msglen > sizeof(buf) - nowlen - 1)
-                msglen = sizeof(buf) - nowlen - 1;
-            memcpy(buf + nowlen, ssh->pktin.data + 14, msglen);
-            buf[nowlen + msglen] = '\0';
+           sfree(buf);
+            buf = dupprintf("Disconnection message text: %n%.*s",
+                           &nowlen, msglen, ssh->pktin.data + 14);
             logevent(buf);
             bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
                      reason,
                      (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
                      ssh2_disconnect_reasons[reason] : "unknown",
                      buf+nowlen));
+           sfree(buf);
             crReturn(0);
         }
         break;
@@ -1217,7 +1207,7 @@ static void s_wrpkt(Ssh ssh)
 {
     int len, backlog;
     len = s_wrpkt_prepare(ssh);
-    backlog = sk_write(ssh->s, ssh->pktout.data, len);
+    backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
     if (backlog > SSH_MAX_BACKLOG)
        ssh_throttle_all(ssh, 1, backlog);
 }
@@ -1253,7 +1243,7 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
            pktlen += 4;
            break;
          case PKT_CHAR:
-           (void) va_arg(ap1, char);
+           (void) va_arg(ap1, int);
            pktlen++;
            break;
          case PKT_DATA:
@@ -1263,7 +1253,7 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
            break;
          case PKT_STR:
            argp = va_arg(ap1, unsigned char *);
-           arglen = strlen(argp);
+           arglen = strlen((char *)argp);
            pktlen += 4 + arglen;
            break;
          case PKT_BIGNUM:
@@ -1286,7 +1276,7 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
            p += 4;
            break;
          case PKT_CHAR:
-           argchar = va_arg(ap2, unsigned char);
+           argchar = (unsigned char) va_arg(ap2, int);
            *p = argchar;
            p++;
            break;
@@ -1298,7 +1288,7 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
            break;
          case PKT_STR:
            argp = va_arg(ap2, unsigned char *);
-           arglen = strlen(argp);
+           arglen = strlen((char *)argp);
            PUT_32BIT(p, arglen);
            memcpy(p + 4, argp, arglen);
            p += 4 + arglen;
@@ -1429,7 +1419,7 @@ static void ssh2_pkt_addstring(Ssh ssh, char *data)
     ssh2_pkt_addstring_start(ssh);
     ssh2_pkt_addstring_str(ssh, data);
 }
-static char *ssh2_mpint_fmt(Bignum b, int *len)
+static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
 {
     unsigned char *p;
     int i, n = (bignum_bitcount(b) + 7) / 8;
@@ -1452,7 +1442,7 @@ static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
     int len;
     p = ssh2_mpint_fmt(b, &len);
     ssh2_pkt_addstring_start(ssh);
-    ssh2_pkt_addstring_data(ssh, p, len);
+    ssh2_pkt_addstring_data(ssh, (char *)p, len);
     sfree(p);
 }
 
@@ -1523,7 +1513,7 @@ static void ssh2_pkt_send(Ssh ssh)
     int len;
     int backlog;
     len = ssh2_pkt_construct(ssh);
-    backlog = sk_write(ssh->s, ssh->pktout.data, len);
+    backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
     if (backlog > SSH_MAX_BACKLOG)
        ssh_throttle_all(ssh, 1, backlog);
 }
@@ -1558,7 +1548,8 @@ static void ssh2_pkt_defer(Ssh ssh)
 static void ssh_pkt_defersend(Ssh ssh)
 {
     int backlog;
-    backlog = sk_write(ssh->s, ssh->deferred_send_data, ssh->deferred_len);
+    backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
+                      ssh->deferred_len);
     ssh->deferred_len = ssh->deferred_size = 0;
     sfree(ssh->deferred_send_data);
     ssh->deferred_send_data = NULL;
@@ -1612,15 +1603,19 @@ static int ssh2_pkt_getbool(Ssh ssh)
 }
 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
 {
+    int len;
     *p = NULL;
     *length = 0;
     if (ssh->pktin.length - ssh->pktin.savedpos < 4)
        return;
-    *length = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
+    len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
+    if (len < 0)
+       return;
+    *length = len;
     ssh->pktin.savedpos += 4;
     if (ssh->pktin.length - ssh->pktin.savedpos < *length)
        return;
-    *p = ssh->pktin.data + ssh->pktin.savedpos;
+    *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
     ssh->pktin.savedpos += *length;
 }
 static Bignum ssh2_pkt_getmp(Ssh ssh)
@@ -1636,7 +1631,7 @@ static Bignum ssh2_pkt_getmp(Ssh ssh)
        bombout((ssh,"internal error: Can't handle negative mpints"));
        return NULL;
     }
-    b = bignum_from_bytes(p, length);
+    b = bignum_from_bytes((unsigned char *)p, length);
     return b;
 }
 
@@ -1686,18 +1681,18 @@ static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
        if (len != siglen) {
            unsigned char newlen[4];
            ssh2_pkt_addstring_start(ssh);
-           ssh2_pkt_addstring_data(ssh, sigblob, pos);
+           ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
            /* dmemdump(sigblob, pos); */
            pos += 4;                  /* point to start of actual sig */
            PUT_32BIT(newlen, len);
-           ssh2_pkt_addstring_data(ssh, newlen, 4);
+           ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
            /* dmemdump(newlen, 4); */
            newlen[0] = 0;
            while (len-- > siglen) {
-               ssh2_pkt_addstring_data(ssh, newlen, 1);
+               ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
                /* dmemdump(newlen, 1); */
            }
-           ssh2_pkt_addstring_data(ssh, sigblob+pos, siglen);
+           ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
            /* dmemdump(sigblob+pos, siglen); */
            return;
        }
@@ -1706,7 +1701,7 @@ static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
     }
 
     ssh2_pkt_addstring_start(ssh);
-    ssh2_pkt_addstring_data(ssh, sigblob, sigblob_len);
+    ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
 }
 
 /*
@@ -1724,8 +1719,8 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     ssh->remote_bugs = 0;
 
-    if (cfg.sshbug_ignore1 == BUG_ON ||
-       (cfg.sshbug_ignore1 == BUG_AUTO &&
+    if (ssh->cfg.sshbug_ignore1 == BUG_ON ||
+       (ssh->cfg.sshbug_ignore1 == BUG_AUTO &&
         (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
          !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
          !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
@@ -1738,8 +1733,8 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        logevent("We believe remote version has SSH1 ignore bug");
     }
 
-    if (cfg.sshbug_plainpw1 == BUG_ON ||
-       (cfg.sshbug_plainpw1 == BUG_AUTO &&
+    if (ssh->cfg.sshbug_plainpw1 == BUG_ON ||
+       (ssh->cfg.sshbug_plainpw1 == BUG_AUTO &&
         (!strcmp(imp, "Cisco-1.25")))) {
        /*
         * These versions need a plain password sent; they can't
@@ -1750,8 +1745,8 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        logevent("We believe remote version needs a plain SSH1 password");
     }
 
-    if (cfg.sshbug_rsa1 == BUG_ON ||
-       (cfg.sshbug_rsa1 == BUG_AUTO &&
+    if (ssh->cfg.sshbug_rsa1 == BUG_ON ||
+       (ssh->cfg.sshbug_rsa1 == BUG_AUTO &&
         (!strcmp(imp, "Cisco-1.25")))) {
        /*
         * These versions apparently have no clue whatever about
@@ -1762,11 +1757,11 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        logevent("We believe remote version can't handle RSA authentication");
     }
 
-    if (cfg.sshbug_hmac2 == BUG_ON ||
-       (cfg.sshbug_hmac2 == BUG_AUTO &&
-        (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
-         !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
-         !strncmp(imp, "2.1 ", 4)))) {
+    if (ssh->cfg.sshbug_hmac2 == BUG_ON ||
+       (ssh->cfg.sshbug_hmac2 == BUG_AUTO &&
+        (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
+         wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
+         wc_match("2.1 *", imp)))) {
        /*
         * These versions have the HMAC bug.
         */
@@ -1774,9 +1769,9 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        logevent("We believe remote version has SSH2 HMAC bug");
     }
 
-    if (cfg.sshbug_derivekey2 == BUG_ON ||
-       (cfg.sshbug_derivekey2 == BUG_AUTO &&
-        (!strncmp(imp, "2.0.", 4)))) {
+    if (ssh->cfg.sshbug_derivekey2 == BUG_ON ||
+       (ssh->cfg.sshbug_derivekey2 == BUG_AUTO &&
+        (wc_match("2.0.0*", imp) || wc_match("2.0.1[01]*", imp) ))) {
        /*
         * These versions have the key-derivation bug (failing to
         * include the literal shared secret in the hashes that
@@ -1786,10 +1781,10 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        logevent("We believe remote version has SSH2 key-derivation bug");
     }
 
-    if (cfg.sshbug_rsapad2 == BUG_ON ||
-       (cfg.sshbug_rsapad2 == BUG_AUTO &&
-        ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
-         (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){
+    if (ssh->cfg.sshbug_rsapad2 == BUG_ON ||
+       (ssh->cfg.sshbug_rsapad2 == BUG_AUTO &&
+        (wc_match("OpenSSH_2.[5-9]*", imp) ||
+         wc_match("OpenSSH_3.[0-2]*", imp)))) {
        /*
         * These versions have the SSH2 RSA padding bug.
         */
@@ -1797,9 +1792,9 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        logevent("We believe remote version has SSH2 RSA padding bug");
     }
 
-    if (cfg.sshbug_dhgex2 == BUG_ON) {
+    if (ssh->cfg.sshbug_dhgex2 == BUG_ON) {
        /*
-        * These versions have the SSH2 DH GEX bug.
+        * User specified the SSH2 DH GEX bug.
         */
        ssh->remote_bugs |= BUG_SSH2_DH_GEX;
        logevent("We believe remote version has SSH2 DH group exchange bug");
@@ -1857,7 +1852,7 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
                s->i = -1;
            } else if (s->i < sizeof(s->version) - 1)
                s->version[s->i++] = c;
-       } else if (c == '\n')
+       } else if (c == '\012')
            break;
     }
 
@@ -1884,16 +1879,16 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
     /* Anything greater or equal to "1.99" means protocol 2 is supported. */
     s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
 
-    if (cfg.sshprot == 0 && !s->proto1) {
+    if (ssh->cfg.sshprot == 0 && !s->proto1) {
        bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
        crReturn(0);
     }
-    if (cfg.sshprot == 3 && !s->proto2) {
+    if (ssh->cfg.sshprot == 3 && !s->proto2) {
        bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
        crReturn(0);
     }
 
-    if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) {
+    if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
        /*
         * Use v2 protocol.
         */
@@ -1907,7 +1902,7 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
        sprintf(vlog, "We claim version: %s", verstring);
        logevent(vlog);
-       strcat(verstring, "\n");
+       strcat(verstring, "\012");
        logevent("Using SSH protocol version 2");
        sk_write(ssh->s, verstring, strlen(verstring));
        ssh->protocol = ssh2_protocol;
@@ -1923,7 +1918,7 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
                sshver);
        sprintf(vlog, "We claim version: %s", verstring);
        logevent(vlog);
-       strcat(verstring, "\n");
+       strcat(verstring, "\012");
 
        logevent("Using SSH protocol version 1");
        sk_write(ssh->s, verstring, strlen(verstring));
@@ -2006,7 +2001,7 @@ static int ssh_closing(Plug plug, char *error_msg, int error_code,
 static int ssh_receive(Plug plug, int urgent, char *data, int len)
 {
     Ssh ssh = (Ssh) plug;
-    ssh_gotdata(ssh, data, len);
+    ssh_gotdata(ssh, (unsigned char *)data, len);
     if (ssh->state == SSH_STATE_CLOSED) {
        if (ssh->s) {
            sk_close(ssh->s);
@@ -2059,27 +2054,23 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
     /*
      * Try to find host.
      */
-    {
-       char buf[200];
-       sprintf(buf, "Looking up host \"%.170s\"", host);
-       logevent(buf);
-    }
-    addr = sk_namelookup(host, realhost);
-    if ((err = sk_addr_error(addr)))
+    logeventf(ssh, "Looking up host \"%s\"", host);
+    addr = name_lookup(host, port, realhost, &ssh->cfg);
+    if ((err = sk_addr_error(addr)) != NULL)
        return err;
 
     /*
      * Open socket.
      */
     {
-       char buf[200], addrbuf[100];
+       char addrbuf[100];
        sk_getaddr(addr, addrbuf, 100);
-       sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
-       logevent(buf);
+       logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
     }
     ssh->fn = &fn_table;
-    ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
-    if ((err = sk_socket_error(ssh->s))) {
+    ssh->s = new_connection(addr, *realhost, port,
+                           0, 1, nodelay, (Plug) ssh, &ssh->cfg);
+    if ((err = sk_socket_error(ssh->s)) != NULL) {
        ssh->s = NULL;
        return err;
     }
@@ -2143,7 +2134,7 @@ static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
  */
 
 /* Set up a username or password input loop on a given buffer. */
-void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
+static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
 {
     ssh->userpass_input_buffer = buffer;
     ssh->userpass_input_buflen = buflen;
@@ -2157,7 +2148,7 @@ void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
  * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
  * for inconclusive (keep waiting for more input please).
  */
-int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
+static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
 {
     char c;
 
@@ -2333,7 +2324,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        char *cipher_string = NULL;
        int i;
        for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
-           int next_cipher = cfg.ssh_cipherlist[i];
+           int next_cipher = ssh->cfg.ssh_cipherlist[i];
            if (next_cipher == CIPHER_WARN) {
                /* If/when we choose a cipher, warn about it */
                warn = 1;
@@ -2396,11 +2387,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                   &ssh_3des);
     ssh->v1_cipher_ctx = ssh->cipher->make_context();
     ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
-    {
-       char buf[256];
-       sprintf(buf, "Initialised %.200s encryption", ssh->cipher->text_name);
-       logevent(buf);
-    }
+    logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
 
     ssh->crcda_ctx = crcda_make_context();
     logevent("Installing CRC compensation attack detector");
@@ -2416,7 +2403,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
     fflush(stdout);
     {
-       if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
+       if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
            if (ssh_get_line && !ssh_getline_pw_only) {
                if (!ssh_get_line("login as: ",
                                  s->username, sizeof(s->username), FALSE)) {
@@ -2443,7 +2430,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                c_write_str(ssh, "\r\n");
            }
        } else {
-           strncpy(s->username, cfg.username, sizeof(s->username));
+           strncpy(s->username, ssh->cfg.username, sizeof(s->username));
            s->username[sizeof(s->username)-1] = '\0';
        }
 
@@ -2469,9 +2456,9 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        s->tried_publickey = s->tried_agent = 0;
     }
     s->tis_auth_refused = s->ccard_auth_refused = 0;
-    /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
-    if (*cfg.keyfile) {
-       if (!rsakey_pubblob(cfg.keyfile,
+    /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
+    if (*ssh->cfg.keyfile) {
+       if (!rsakey_pubblob(ssh->cfg.keyfile,
                            &s->publickey_blob, &s->publickey_bloblen))
            s->publickey_blob = NULL;
     } else
@@ -2522,7 +2509,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    s->p += ssh1_read_bignum(s->p, &s->key.modulus);
                    s->commentlen = GET_32BIT(s->p);
                    s->p += 4;
-                   s->commentp = s->p;
+                   s->commentp = (char *)s->p;
                    s->p += s->commentlen;
                    send_packet(ssh, SSH1_CMSG_AUTH_RSA,
                                PKT_BIGNUM, s->key.modulus, PKT_END);
@@ -2599,10 +2586,10 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            if (s->authed)
                break;
        }
-       if (*cfg.keyfile && !s->tried_publickey)
+       if (*ssh->cfg.keyfile && !s->tried_publickey)
            s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
 
-       if (cfg.try_tis_auth &&
+       if (ssh->cfg.try_tis_auth &&
            (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
            !s->tis_auth_refused) {
            s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
@@ -2629,7 +2616,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                s->prompt[(sizeof s->prompt) - 1] = '\0';
            }
        }
-       if (cfg.try_tis_auth &&
+       if (ssh->cfg.try_tis_auth &&
            (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
            !s->ccard_auth_refused) {
            s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
@@ -2664,9 +2651,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            char msgbuf[256];
            if (flags & FLAG_VERBOSE)
                c_write_str(ssh, "Trying public key authentication.\r\n");
-           sprintf(msgbuf, "Trying public key \"%.200s\"", cfg.keyfile);
-           logevent(msgbuf);
-           type = key_type(cfg.keyfile);
+           logeventf(ssh, "Trying public key \"%s\"", ssh->cfg.keyfile);
+           type = key_type(ssh->cfg.keyfile);
            if (type != SSH_KEYTYPE_SSH1) {
                sprintf(msgbuf, "Key is of wrong type (%s)",
                        key_type_to_str(type));
@@ -2676,7 +2662,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                s->tried_publickey = 1;
                continue;
            }
-           if (!rsakey_encrypted(cfg.keyfile, &comment)) {
+           if (!rsakey_encrypted(ssh->cfg.keyfile, &comment)) {
                if (flags & FLAG_VERBOSE)
                    c_write_str(ssh, "No passphrase required.\r\n");
                goto tryauth;
@@ -2732,10 +2718,10 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            s->tried_publickey = 1;
            
            {
-               int ret = loadrsakey(cfg.keyfile, &s->key, s->password);
+               int ret = loadrsakey(ssh->cfg.keyfile, &s->key, s->password);
                if (ret == 0) {
                    c_write_str(ssh, "Couldn't load private key from ");
-                   c_write_str(ssh, cfg.keyfile);
+                   c_write_str(ssh, ssh->cfg.keyfile);
                    c_write_str(ssh, ".\r\n");
                    continue;          /* go and try password */
                }
@@ -3019,7 +3005,7 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     if (ssh->state == SSH_STATE_CLOSED)
        crReturnV;
 
-    if (cfg.agentfwd && agent_exists()) {
+    if (ssh->cfg.agentfwd && agent_exists()) {
        logevent("Requesting agent forwarding");
        send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
        do {
@@ -3037,15 +3023,17 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        }
     }
 
-    if (cfg.x11_forward) {
+    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));
+                                      data, sizeof(data), ssh->cfg.x11_auth);
+        x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
        if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
            send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
                        PKT_STR, proto, PKT_STR, data,
-                       PKT_INT, 0, PKT_END);
+                       PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
+                       PKT_END);
        } else {
            send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
                        PKT_STR, proto, PKT_STR, data, PKT_END);
@@ -3069,91 +3057,104 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        char type;
        int n;
        int sport,dport,sserv,dserv;
-       char sports[256], dports[256], host[256];
-       char buf[1024];
-       struct servent *se;
+       char sports[256], dports[256], saddr[256], host[256];
 
        ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
         /* Add port forwardings. */
-       ssh->portfwd_strptr = cfg.portfwd;
+       ssh->portfwd_strptr = ssh->cfg.portfwd;
        while (*ssh->portfwd_strptr) {
            type = *ssh->portfwd_strptr++;
+           saddr[0] = '\0';
            n = 0;
-           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
-               sports[n++] = *ssh->portfwd_strptr++;
+           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
+               if (*ssh->portfwd_strptr == ':') {
+                   /*
+                    * We've seen a colon in the middle of the
+                    * source port number. This means that
+                    * everything we've seen until now is the
+                    * source _address_, so we'll move it into
+                    * saddr and start sports from the beginning
+                    * again.
+                    */
+                   ssh->portfwd_strptr++;
+                   sports[n] = '\0';
+                   strcpy(saddr, sports);
+                   n = 0;
+               }
+               if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
+           }
            sports[n] = 0;
            if (*ssh->portfwd_strptr == '\t')
                ssh->portfwd_strptr++;
            n = 0;
-           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
-               host[n++] = *ssh->portfwd_strptr++;
+           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
+               if (n < 255) host[n++] = *ssh->portfwd_strptr++;
+           }
            host[n] = 0;
            if (*ssh->portfwd_strptr == ':')
                ssh->portfwd_strptr++;
            n = 0;
-           while (*ssh->portfwd_strptr)
-               dports[n++] = *ssh->portfwd_strptr++;
+           while (*ssh->portfwd_strptr) {
+               if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
+           }
            dports[n] = 0;
            ssh->portfwd_strptr++;
            dport = atoi(dports);
            dserv = 0;
            if (dport == 0) {
                dserv = 1;
-               se = getservbyname(dports, NULL);
-               if (se != NULL) {
-                   dport = ntohs(se->s_port);
-               } else {
-                   sprintf(buf,
-                           "Service lookup failed for destination port \"%s\"",
-                           dports);
-                   logevent(buf);
+               dport = net_service_lookup(dports);
+               if (!dport) {
+                   logeventf(ssh, "Service lookup failed for"
+                             " destination port \"%s\"", dports);
                }
            }
            sport = atoi(sports);
            sserv = 0;
            if (sport == 0) {
                sserv = 1;
-               se = getservbyname(sports, NULL);
-               if (se != NULL) {
-                   sport = ntohs(se->s_port);
-               } else {
-                   sprintf(buf,
-                           "Service lookup failed for source port \"%s\"",
-                           sports);
-                   logevent(buf);
+               sport = net_service_lookup(sports);
+               if (!sport) {
+                   logeventf(ssh, "Service lookup failed for source"
+                             " port \"%s\"", sports);
                }
            }
            if (sport && dport) {
                if (type == 'L') {
-                   pfd_addforward(host, dport, sport, ssh);
-                   sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to"
-                           " %s:%.*s%.*s%d%.*s",
-                           sserv ? strlen(sports) : 0, sports,
-                           sserv, "(", sport, sserv, ")",
-                           host,
-                           dserv ? strlen(dports) : 0, dports,
-                           dserv, "(", dport, dserv, ")");
-                   logevent(buf);
+                   pfd_addforward(host, dport, *saddr ? saddr : NULL,
+                                  sport, ssh, &ssh->cfg);
+                   logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
+                             " forwarding to %s:%.*s%.*s%d%.*s",
+                             (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
+                             (int)(*saddr?1:0), ":",
+                             (int)(sserv ? strlen(sports) : 0), sports,
+                             sserv, "(", sport, sserv, ")",
+                             host,
+                             (int)(dserv ? strlen(dports) : 0), dports,
+                             dserv, "(", dport, dserv, ")");
                } else {
                    struct ssh_rportfwd *pf;
                    pf = smalloc(sizeof(*pf));
                    strcpy(pf->dhost, host);
                    pf->dport = dport;
+                   if (saddr) {
+                       logeventf(ssh,
+                                 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
+                                 saddr, sport);
+                   }
                    if (add234(ssh->rportfwds, pf) != pf) {
-                       sprintf(buf, 
-                               "Duplicate remote port forwarding to %s:%d",
-                               host, dport);
-                       logevent(buf);
+                       logeventf(ssh, 
+                                 "Duplicate remote port forwarding to %s:%d",
+                                 host, dport);
                        sfree(pf);
                    } else {
-                       sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s"
-                               " forward to %s:%.*s%.*s%d%.*s",
-                           sserv ? strlen(sports) : 0, sports,
-                           sserv, "(", sport, sserv, ")",
-                           host,
-                           dserv ? strlen(dports) : 0, dports,
-                           dserv, "(", dport, dserv, ")");
-                       logevent(buf);
+                       logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
+                                 " forward to %s:%.*s%.*s%d%.*s",
+                                 (int)(sserv ? strlen(sports) : 0), sports,
+                                 sserv, "(", sport, sserv, ")",
+                                 host,
+                                 (int)(dserv ? strlen(dports) : 0), dports,
+                                 dserv, "(", dport, dserv, ")");
                        send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
                                    PKT_INT, sport,
                                    PKT_STR, host,
@@ -3177,9 +3178,9 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        }
     }
 
-    if (!cfg.nopty) {
+    if (!ssh->cfg.nopty) {
        send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
-                   PKT_STR, cfg.termtype,
+                   PKT_STR, ssh->cfg.termtype,
                    PKT_INT, ssh->term_height,
                    PKT_INT, ssh->term_width,
                    PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
@@ -3200,7 +3201,7 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        ssh->editing = ssh->echoing = 1;
     }
 
-    if (cfg.compression) {
+    if (ssh->cfg.compression) {
        send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
        do {
            crReturnV;
@@ -3228,10 +3229,10 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      * exists, we fall straight back to that.
      */
     {
-       char *cmd = cfg.remote_cmd_ptr;
+       char *cmd = ssh->cfg.remote_cmd_ptr;
        
-       if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
-           cmd = cfg.remote_cmd_ptr2;
+       if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
+           cmd = ssh->cfg.remote_cmd_ptr2;
            ssh->fallback_cmd = TRUE;
        }
        if (*cmd)
@@ -3260,7 +3261,7 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                int bufsize =
                    from_backend(ssh->frontend,
                                 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
-                                ssh->pktin.body + 4, len);
+                                (char *)(ssh->pktin.body) + 4, len);
                if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
                    ssh->v1_stdout_throttling = 1;
                    ssh1_throttle(ssh, +1);
@@ -3284,8 +3285,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    c = smalloc(sizeof(struct ssh_channel));
                    c->ssh = ssh;
 
-                   if (x11_init(&c->u.x11.s, cfg.x11_display, c,
-                                ssh->x11auth) != NULL) {
+                   if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
+                                ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
                        logevent("opening X11 forward connection failed");
                        sfree(c);
                        send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
@@ -3341,7 +3342,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                c->ssh = ssh;
 
                hostsize = GET_32BIT(ssh->pktin.body+4);
-               for(h = host, p = ssh->pktin.body+8; hostsize != 0; hostsize--) {
+               for (h = host, p = (char *)(ssh->pktin.body+8);
+                    hostsize != 0; hostsize--) {
                    if (h+1 < host+sizeof(host))
                        *h++ = *p;
                    p++;
@@ -3362,7 +3364,7 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    sprintf(buf, "Received remote port open request for %s:%d",
                            host, port);
                    logevent(buf);
-                   e = pfd_newconnect(&c->u.pfd.s, host, port, c);
+                   e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
                    if (e != NULL) {
                        char buf[256];
                        sprintf(buf, "Port open failed: %s", e);
@@ -3411,7 +3413,6 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
            } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
                unsigned int remoteid = GET_32BIT(ssh->pktin.body);
-               unsigned int localid = GET_32BIT(ssh->pktin.body+4);
                struct ssh_channel *c;
 
                c = find234(ssh->channels, &remoteid, ssh_channelfind);
@@ -3474,10 +3475,10 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    int bufsize;
                    switch (c->type) {
                      case CHAN_X11:
-                       bufsize = x11_send(c->u.x11.s, p, len);
+                       bufsize = x11_send(c->u.x11.s, (char *)p, len);
                        break;
                      case CHAN_SOCKDATA:
-                       bufsize = pfd_send(c->u.pfd.s, p, len);
+                       bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
                        break;
                      case CHAN_AGENT:
                        /* Data for an agent message. Buffer it. */
@@ -3582,7 +3583,10 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
  */
 static int in_commasep_string(char *needle, char *haystack, int haylen)
 {
-    int needlen = strlen(needle);
+    int needlen;
+    if (!needle || !haystack)         /* protect against null pointers */
+       return 0;
+    needlen = strlen(needle);
     while (1) {
        /*
         * Is it at the start of the string?
@@ -3608,8 +3612,9 @@ static int in_commasep_string(char *needle, char *haystack, int haylen)
 /*
  * SSH2 key creation method.
  */
-static void ssh2_mkkey(Ssh ssh, Bignum K, char *H, char *sessid, char chr,
-                      char *keyspace)
+static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
+                      unsigned char *sessid, char chr,
+                      unsigned char *keyspace)
 {
     SHA_State s;
     /* First 20 bytes. */
@@ -3673,12 +3678,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
         */
        s->n_preferred_ciphers = 0;
        for (i = 0; i < CIPHER_MAX; i++) {
-           switch (cfg.ssh_cipherlist[i]) {
+           switch (ssh->cfg.ssh_cipherlist[i]) {
              case CIPHER_BLOWFISH:
                s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
                break;
              case CIPHER_DES:
-               if (cfg.ssh2_des_cbc) {
+               if (ssh->cfg.ssh2_des_cbc) {
                    s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
                }
                break;
@@ -3702,7 +3707,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Set up preferred compression.
      */
-    if (cfg.compression)
+    if (ssh->cfg.compression)
        s->preferred_comp = &ssh_zlib;
     else
        s->preferred_comp = &ssh_comp_none;
@@ -3817,7 +3822,8 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
     if (!ispkt)
        crWaitUntil(ispkt);
-    sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
+    if (ssh->pktin.length > 5)
+       sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
 
     /*
      * Now examine the other side's KEXINIT to see what we're up
@@ -3878,7 +3884,8 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            }
        }
        if (!s->cscipher_tobe) {
-           bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)", str));
+           bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
+                    str ? str : "(null)"));
            crReturn(0);
        }
 
@@ -3903,7 +3910,8 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            }
        }
        if (!s->sccipher_tobe) {
-           bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)", str));
+           bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
+                    str ? str : "(null)"));
            crReturn(0);
        }
 
@@ -4023,6 +4031,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     SHA_Final(&ssh->exhash, s->exchange_hash);
 
     dh_cleanup(ssh->kex_ctx);
+    ssh->kex_ctx = NULL;
 
 #if 0
     debug(("Exchange hash is:\n"));
@@ -4032,7 +4041,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
     if (!s->hkey ||
        !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
-                                s->exchange_hash, 20)) {
+                                (char *)s->exchange_hash, 20)) {
        bombout((ssh,"Server's host key did not match the signature supplied"));
        crReturn(0);
     }
@@ -4124,26 +4133,16 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
        ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
     }
-    {
-       char buf[256];
-       sprintf(buf, "Initialised %.200s client->server encryption",
-               ssh->cscipher->text_name);
-       logevent(buf);
-       sprintf(buf, "Initialised %.200s server->client encryption",
-               ssh->sccipher->text_name);
-       logevent(buf);
-       if (ssh->cscomp->text_name) {
-           sprintf(buf, "Initialised %.200s compression",
-                   ssh->cscomp->text_name);
-           logevent(buf);
-       }
-       if (ssh->sccomp->text_name) {
-           sprintf(buf, "Initialised %.200s decompression",
-                   ssh->sccomp->text_name);
-           logevent(buf);
-       }
-    }
-
+    logeventf(ssh, "Initialised %.200s client->server encryption",
+             ssh->cscipher->text_name);
+    logeventf(ssh, "Initialised %.200s server->client encryption",
+             ssh->sccipher->text_name);
+    if (ssh->cscomp->text_name)
+       logeventf(ssh, "Initialised %s compression",
+                 ssh->cscomp->text_name);
+    if (ssh->sccomp->text_name)
+       logeventf(ssh, "Initialised %s decompression",
+                 ssh->sccomp->text_name);
 
     /*
      * If this is the first key exchange phase, we must pass the
@@ -4324,13 +4323,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        /*
         * Get a username.
         */
-       if (s->got_username && !cfg.change_username) {
+       if (s->got_username && !ssh->cfg.change_username) {
            /*
             * We got a username last time round this loop, and
             * with change_username turned off we don't try to get
             * it again.
             */
-       } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
+       } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
            if (ssh_get_line && !ssh_getline_pw_only) {
                if (!ssh_get_line("login as: ",
                                  s->username, sizeof(s->username), FALSE)) {
@@ -4353,16 +4352,17 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                } while (ret == 0);
                if (ret < 0)
                    cleanup_exit(0);
+               c_write_str(ssh, "\r\n");
            }
-           c_write_str(ssh, "\r\n");
            s->username[strcspn(s->username, "\n\r")] = '\0';
        } else {
-           char stuff[200];
-           strncpy(s->username, cfg.username, sizeof(s->username));
+           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)) {
-               sprintf(stuff, "Using username \"%s\".\r\n", s->username);
+               stuff = dupprintf("Using username \"%s\".\r\n", s->username);
                c_write_str(ssh, stuff);
+               sfree(stuff);
            }
        }
        s->got_username = TRUE;
@@ -4387,24 +4387,24 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        s->tried_agent = FALSE;
        s->tried_keyb_inter = FALSE;
        s->kbd_inter_running = FALSE;
-       /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
-       if (*cfg.keyfile) {
+       /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
+       if (*ssh->cfg.keyfile) {
            int keytype;
-           logeventf(ssh->frontend,
-                     "Reading private key file \"%.150s\"", cfg.keyfile);
-           keytype = key_type(cfg.keyfile);
+           logeventf(ssh, "Reading private key file \"%.150s\"", ssh->cfg.keyfile);
+           keytype = key_type(ssh->cfg.keyfile);
            if (keytype == SSH_KEYTYPE_SSH2) {
                s->publickey_blob =
-                   ssh2_userkey_loadpub(cfg.keyfile, NULL,
+                   ssh2_userkey_loadpub(ssh->cfg.keyfile, NULL,
                                         &s->publickey_bloblen);
            } else {
-               char msgbuf[256];
-               logeventf(ssh->frontend,
-                         "Unable to use this key file (%s)",
+               char *msgbuf;
+               logeventf(ssh, "Unable to use this key file (%s)",
                          key_type_to_str(keytype));
-               sprintf(msgbuf, "Unable to use key file \"%.150s\" (%s)\r\n",
-                       cfg.keyfile, key_type_to_str(keytype));
+               msgbuf = dupprintf("Unable to use key file \"%.150s\""
+                                  " (%s)\r\n", ssh->cfg.keyfile,
+                                  key_type_to_str(keytype));
                c_write_str(ssh, msgbuf);
+               sfree(msgbuf);
                s->publickey_blob = NULL;
            }
        } else
@@ -4517,7 +4517,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    in_commasep_string("publickey", methods, methlen);
                s->can_passwd =
                    in_commasep_string("password", methods, methlen);
-               s->can_keyb_inter = cfg.try_ki_auth &&
+               s->can_keyb_inter = ssh->cfg.try_ki_auth &&
                    in_commasep_string("keyboard-interactive", methods, methlen);
            }
 
@@ -4579,13 +4579,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                            logevent("This key matches configured key file");
                            s->tried_pubkey_config = 1;
                        }
-                       s->pkblob = s->p;
+                       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 = s->p;
+                       s->commentp = (char *)s->p;
                        s->p += s->commentlen;
                        ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
                        ssh2_pkt_addstring(ssh, s->username);
@@ -4691,8 +4691,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 * First, offer the public blob to see if the server is
                 * willing to accept it.
                 */
-               pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
-                                               &pub_blob_len);
+               pub_blob =
+                   (unsigned char *)ssh2_userkey_loadpub(ssh->cfg.keyfile,
+                                                         &algorithm,
+                                                         &pub_blob_len);
                if (pub_blob) {
                    ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
                    ssh2_pkt_addstring(ssh, s->username);
@@ -4701,7 +4703,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    ssh2_pkt_addbool(ssh, FALSE);       /* no signature included */
                    ssh2_pkt_addstring(ssh, algorithm);
                    ssh2_pkt_addstring_start(ssh);
-                   ssh2_pkt_addstring_data(ssh, pub_blob, pub_blob_len);
+                   ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
+                                           pub_blob_len);
                    ssh2_pkt_send(ssh);
                    logevent("Offered public key");     /* FIXME */
 
@@ -4717,7 +4720,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * Actually attempt a serious authentication using
                     * the key.
                     */
-                   if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
+                   if (ssh2_userkey_encrypted(ssh->cfg.keyfile, &comment)) {
                        sprintf(s->pwprompt,
                                "Passphrase for key \"%.100s\": ",
                                comment);
@@ -4869,7 +4872,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 */
                struct ssh2_userkey *key;
 
-               key = ssh2_load_userkey(cfg.keyfile, s->password);
+               key = ssh2_load_userkey(ssh->cfg.keyfile, s->password);
                if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
                    if (key == SSH2_WRONG_PASSPHRASE) {
                        c_write_str(ssh, "Wrong passphrase\r\n");
@@ -4902,7 +4905,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    ssh2_pkt_addstring(ssh, key->alg->name);
                    pkblob = key->alg->public_blob(key->data, &pkblob_len);
                    ssh2_pkt_addstring_start(ssh);
-                   ssh2_pkt_addstring_data(ssh, pkblob, pkblob_len);
+                   ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
 
                    /*
                     * The data to be signed is:
@@ -4918,7 +4921,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    memcpy(sigdata + 4, ssh->v2_session_id, 20);
                    memcpy(sigdata + 24, ssh->pktout.data + 5,
                           ssh->pktout.length - 5);
-                   sigblob = key->alg->sign(key->data, sigdata,
+                   sigblob = key->alg->sign(key->data, (char *)sigdata,
                                             sigdata_len, &sigblob_len);
                    ssh2_add_sigblob(ssh, pkblob, pkblob_len,
                                     sigblob, sigblob_len);
@@ -4950,6 +4953,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                ssh2_pkt_addstring(ssh, "password");
                ssh2_pkt_addbool(ssh, FALSE);
                ssh2_pkt_addstring(ssh, s->password);
+               memset(s->password, 0, sizeof(s->password));
                ssh2_pkt_defer(ssh);
                /*
                 * We'll include a string that's an exact multiple of the
@@ -5070,11 +5074,12 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Potentially enable X11 forwarding.
      */
-    if (cfg.x11_forward) {
+    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));
+                                      data, sizeof(data), ssh->cfg.x11_auth);
+        x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
        ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
        ssh2_pkt_addstring(ssh, "x11-req");
@@ -5082,7 +5087,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        ssh2_pkt_addbool(ssh, 0);              /* many connections */
        ssh2_pkt_addstring(ssh, proto);
        ssh2_pkt_addstring(ssh, data);
-       ssh2_pkt_adduint32(ssh, 0);            /* screen number */
+       ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
        ssh2_pkt_send(ssh);
 
        do {
@@ -5117,71 +5122,81 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        char type;
        int n;
        int sport,dport,sserv,dserv;
-       char sports[256], dports[256], host[256];
-       char buf[1024];
-       struct servent *se;
+       char sports[256], dports[256], saddr[256], host[256];
 
        ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
         /* Add port forwardings. */
-       ssh->portfwd_strptr = cfg.portfwd;
+       ssh->portfwd_strptr = ssh->cfg.portfwd;
        while (*ssh->portfwd_strptr) {
            type = *ssh->portfwd_strptr++;
+           saddr[0] = '\0';
            n = 0;
-           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
-               sports[n++] = *ssh->portfwd_strptr++;
+           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
+               if (*ssh->portfwd_strptr == ':') {
+                   /*
+                    * We've seen a colon in the middle of the
+                    * source port number. This means that
+                    * everything we've seen until now is the
+                    * source _address_, so we'll move it into
+                    * saddr and start sports from the beginning
+                    * again.
+                    */
+                   ssh->portfwd_strptr++;
+                   sports[n] = '\0';
+                   strcpy(saddr, sports);
+                   n = 0;
+               }
+               if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
+           }
            sports[n] = 0;
            if (*ssh->portfwd_strptr == '\t')
                ssh->portfwd_strptr++;
            n = 0;
-           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
-               host[n++] = *ssh->portfwd_strptr++;
+           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
+               if (n < 255) host[n++] = *ssh->portfwd_strptr++;
+           }
            host[n] = 0;
            if (*ssh->portfwd_strptr == ':')
                ssh->portfwd_strptr++;
            n = 0;
-           while (*ssh->portfwd_strptr)
-               dports[n++] = *ssh->portfwd_strptr++;
+           while (*ssh->portfwd_strptr) {
+               if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
+           }
            dports[n] = 0;
            ssh->portfwd_strptr++;
            dport = atoi(dports);
            dserv = 0;
            if (dport == 0) {
                dserv = 1;
-               se = getservbyname(dports, NULL);
-               if (se != NULL) {
-                   dport = ntohs(se->s_port);
-               } else {
-                   sprintf(buf,
-                           "Service lookup failed for destination port \"%s\"",
-                           dports);
-                   logevent(buf);
+               dport = net_service_lookup(dports);
+               if (!dport) {
+                   logeventf(ssh, "Service lookup failed for destination"
+                             " port \"%s\"", dports);
                }
            }
            sport = atoi(sports);
            sserv = 0;
            if (sport == 0) {
                sserv = 1;
-               se = getservbyname(sports, NULL);
-               if (se != NULL) {
-                   sport = ntohs(se->s_port);
-               } else {
-                   sprintf(buf,
-                           "Service lookup failed for source port \"%s\"",
-                           sports);
-                   logevent(buf);
+               sport = net_service_lookup(sports);
+               if (!sport) {
+                   logeventf(ssh, "Service lookup failed for source"
+                             " port \"%s\"", sports);
                }
            }
            if (sport && dport) {
                if (type == 'L') {
-                   pfd_addforward(host, dport, sport, ssh);
-                   sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to"
-                           " %s:%.*s%.*s%d%.*s",
-                           sserv ? strlen(sports) : 0, sports,
-                           sserv, "(", sport, sserv, ")",
-                           host,
-                           dserv ? strlen(dports) : 0, dports,
-                           dserv, "(", dport, dserv, ")");
-                   logevent(buf);
+                   pfd_addforward(host, dport, *saddr ? saddr : NULL,
+                                  sport, ssh, &ssh->cfg);
+                   logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
+                             " forwarding to %s:%.*s%.*s%d%.*s",
+                             (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
+                             (int)(*saddr?1:0), ":",
+                             (int)(sserv ? strlen(sports) : 0), sports,
+                             sserv, "(", sport, sserv, ")",
+                             host,
+                             (int)(dserv ? strlen(dports) : 0), dports,
+                             dserv, "(", dport, dserv, ")");
                } else {
                    struct ssh_rportfwd *pf;
                    pf = smalloc(sizeof(*pf));
@@ -5189,24 +5204,27 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    pf->dport = dport;
                    pf->sport = sport;
                    if (add234(ssh->rportfwds, pf) != pf) {
-                       sprintf(buf, 
-                               "Duplicate remote port forwarding to %s:%d",
-                               host, dport);
-                       logevent(buf);
+                       logeventf(ssh, "Duplicate remote port forwarding"
+                                 " to %s:%d", host, dport);
                        sfree(pf);
                    } else {
-                       sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s"
-                               " forward to %s:%.*s%.*s%d%.*s",
-                           sserv ? strlen(sports) : 0, sports,
-                           sserv, "(", sport, sserv, ")",
-                           host,
-                           dserv ? strlen(dports) : 0, dports,
-                           dserv, "(", dport, dserv, ")");
-                       logevent(buf);
+                       logeventf(ssh, "Requesting remote port "
+                                 "%.*s%.*s%.*s%.*s%d%.*s"
+                                 " forward to %s:%.*s%.*s%d%.*s",
+                                 (int)(*saddr?strlen(saddr):0),
+                                 *saddr?saddr:NULL,
+                                 (int)(*saddr?1:0), ":",
+                                 (int)(sserv ? strlen(sports) : 0), sports,
+                                 sserv, "(", sport, sserv, ")",
+                                 host,
+                                 (int)(dserv ? strlen(dports) : 0), dports,
+                                 dserv, "(", dport, dserv, ")");
                        ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
                        ssh2_pkt_addstring(ssh, "tcpip-forward");
                        ssh2_pkt_addbool(ssh, 1);/* want reply */
-                       if (cfg.rport_acceptall)
+                       if (*saddr)
+                           ssh2_pkt_addstring(ssh, saddr);
+                       if (ssh->cfg.rport_acceptall)
                            ssh2_pkt_addstring(ssh, "0.0.0.0");
                        else
                            ssh2_pkt_addstring(ssh, "127.0.0.1");
@@ -5245,7 +5263,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Potentially enable agent forwarding.
      */
-    if (cfg.agentfwd && agent_exists()) {
+    if (ssh->cfg.agentfwd && agent_exists()) {
        logevent("Requesting OpenSSH-style agent forwarding");
        ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
@@ -5281,12 +5299,12 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Now allocate a pty for the session.
      */
-    if (!cfg.nopty) {
+    if (!ssh->cfg.nopty) {
        ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);       /* recipient channel */
        ssh2_pkt_addstring(ssh, "pty-req");
        ssh2_pkt_addbool(ssh, 1);              /* want reply */
-       ssh2_pkt_addstring(ssh, cfg.termtype);
+       ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
        ssh2_pkt_adduint32(ssh, ssh->term_width);
        ssh2_pkt_adduint32(ssh, ssh->term_height);
        ssh2_pkt_adduint32(ssh, 0);            /* pixel width */
@@ -5333,11 +5351,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        char *cmd;
 
        if (ssh->fallback_cmd) {
-           subsys = cfg.ssh_subsys2;
-           cmd = cfg.remote_cmd_ptr2;
+           subsys = ssh->cfg.ssh_subsys2;
+           cmd = ssh->cfg.remote_cmd_ptr2;
        } else {
-           subsys = cfg.ssh_subsys;
-           cmd = cfg.remote_cmd_ptr;
+           subsys = ssh->cfg.ssh_subsys;
+           cmd = ssh->cfg.remote_cmd_ptr;
        }
 
        ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
@@ -5378,7 +5396,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
             * not, and if the fallback command exists, try falling
             * back to it before complaining.
             */
-           if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
+           if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
                logevent("Primary command failed; attempting fallback");
                ssh->fallback_cmd = TRUE;
                continue;
@@ -5581,8 +5599,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                unsigned i = ssh2_pkt_getuint32(ssh);
                struct ssh_channel *c;
                c = find234(ssh->channels, &i, ssh_channelfind);
-               if (!c)
-                   continue;          /* nonexistent channel */
+               if (!c || c->closes)
+                   continue;          /* nonexistent or closing channel */
                c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
                s->try_send = TRUE;
            } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
@@ -5706,6 +5724,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
                char *type;
                int typelen;
+               char *peeraddr;
+               int peeraddrlen;
+               int port;
                char *error = NULL;
                struct ssh_channel *c;
                unsigned remid, winsize, pktsize;
@@ -5716,16 +5737,25 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                remid = ssh2_pkt_getuint32(ssh);
                winsize = ssh2_pkt_getuint32(ssh);
                pktsize = ssh2_pkt_getuint32(ssh);
+               ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
+               port = ssh2_pkt_getuint32(ssh);
 
                if (typelen == 3 && !memcmp(type, "x11", 3)) {
+                   char *addrstr = smalloc(peeraddrlen+1);
+                   memcpy(addrstr, peeraddr, peeraddrlen);
+                   peeraddr[peeraddrlen] = '\0';
+
                    if (!ssh->X11_fwd_enabled)
                        error = "X11 forwarding is not enabled";
-                   else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
-                                     ssh->x11auth) != NULL) {
+                   else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
+                                     ssh->x11auth, addrstr, port,
+                                     &ssh->cfg) != NULL) {
                        error = "Unable to open an X11 connection";
                    } else {
                        c->type = CHAN_X11;
                    }
+
+                   sfree(addrstr);
                } else if (typelen == 15 &&
                           !memcmp(type, "forwarded-tcpip", 15)) {
                    struct ssh_rportfwd pf, *realpf;
@@ -5738,14 +5768,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        error = "Remote port is not recognised";
                    } else {
                        char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
-                                                realpf->dport, c);
-                       char buf[1024];
-                       sprintf(buf, "Received remote port open request for %s:%d",
-                               realpf->dhost, realpf->dport);
-                       logevent(buf);
+                                                realpf->dport, c, &ssh->cfg);
+                       logeventf(ssh, "Received remote port open request"
+                                 " for %s:%d", realpf->dhost, realpf->dport);
                        if (e != NULL) {
-                           sprintf(buf, "Port open failed: %s", e);
-                           logevent(buf);
+                           logeventf(ssh, "Port open failed: %s", e);
                            error = "Port open failed";
                        } else {
                            logevent("Forwarded port opened successfully");
@@ -5796,7 +5823,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            /*
             * We have spare data. Add it to the channel buffer.
             */
-           ssh2_add_channel_data(ssh->mainchan, in, inlen);
+           ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
            s->try_send = TRUE;
        }
        if (s->try_send) {
@@ -5806,7 +5833,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
             * Try to send data on all channels if we can.
             */
            for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
-               int bufsize = ssh2_try_send(c);
+               int bufsize;
+               if (c->closes)
+                   continue;          /* don't send on closing channels */
+               bufsize = ssh2_try_send(c);
                if (bufsize == 0) {
                    switch (c->type) {
                      case CHAN_MAINSESSION:
@@ -5848,12 +5878,14 @@ static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
  * Returns an error message, or NULL on success.
  */
 static char *ssh_init(void *frontend_handle, void **backend_handle,
+                     Config *cfg,
                      char *host, int port, char **realhost, int nodelay)
 {
     char *p;
     Ssh ssh;
 
     ssh = smalloc(sizeof(*ssh));
+    ssh->cfg = *cfg;                  /* STRUCTURE COPY */
     ssh->s = NULL;
     ssh->cipher = NULL;
     ssh->v1_cipher_ctx = NULL;
@@ -5902,6 +5934,9 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->do_ssh1_login_state = NULL;
     ssh->do_ssh2_transport_state = NULL;
     ssh->do_ssh2_authconn_state = NULL;
+    ssh->mainchan = NULL;
+    ssh->throttled_all = 0;
+    ssh->v1_stdout_throttling = 0;
 
     *backend_handle = ssh;
 
@@ -5911,8 +5946,11 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
 #endif
 
     ssh->frontend = frontend_handle;
-    ssh->term_width = cfg.width;
-    ssh->term_height = cfg.height;
+    ssh->term_width = ssh->cfg.width;
+    ssh->term_height = ssh->cfg.height;
+
+    ssh->channels = NULL;
+    ssh->rportfwds = NULL;
 
     ssh->send_ok = 0;
     ssh->editing = 0;
@@ -5921,6 +5959,8 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->overall_bufsize = 0;
     ssh->fallback_cmd = 0;
 
+    ssh->protocol = NULL;
+
     p = connect_to_host(ssh, host, port, realhost, nodelay);
     if (p != NULL)
        return p;
@@ -5928,6 +5968,80 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     return NULL;
 }
 
+static void ssh_free(void *handle)
+{
+    Ssh ssh = (Ssh) handle;
+    struct ssh_channel *c;
+    struct ssh_rportfwd *pf;
+
+    if (ssh->v1_cipher_ctx)
+       ssh->cipher->free_context(ssh->v1_cipher_ctx);
+    if (ssh->cs_cipher_ctx)
+       ssh->cscipher->free_context(ssh->cs_cipher_ctx);
+    if (ssh->sc_cipher_ctx)
+       ssh->sccipher->free_context(ssh->sc_cipher_ctx);
+    if (ssh->cs_mac_ctx)
+       ssh->csmac->free_context(ssh->cs_mac_ctx);
+    if (ssh->sc_mac_ctx)
+       ssh->scmac->free_context(ssh->sc_mac_ctx);
+    if (ssh->cs_comp_ctx)
+       ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
+    if (ssh->sc_comp_ctx)
+       ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
+    if (ssh->kex_ctx)
+       dh_cleanup(ssh->kex_ctx);
+    sfree(ssh->savedhost);
+
+    if (ssh->channels) {
+       while ((c = delpos234(ssh->channels, 0)) != NULL) {
+           switch (c->type) {
+             case CHAN_X11:
+               if (c->u.x11.s != NULL)
+                   x11_close(c->u.x11.s);
+               break;
+             case CHAN_SOCKDATA:
+               if (c->u.pfd.s != NULL)
+                   pfd_close(c->u.pfd.s);
+               break;
+           }
+           sfree(c);
+       }
+       freetree234(ssh->channels);
+    }
+
+    if (ssh->rportfwds) {
+       while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
+           sfree(pf);
+       freetree234(ssh->rportfwds);
+    }
+    sfree(ssh->deferred_send_data);
+    if (ssh->x11auth)
+       x11_free_auth(ssh->x11auth);
+    sfree(ssh->do_ssh_init_state);
+    sfree(ssh->do_ssh1_login_state);
+    sfree(ssh->do_ssh2_transport_state);
+    sfree(ssh->do_ssh2_authconn_state);
+    
+    if (ssh->s)
+       sk_close(ssh->s);
+    sfree(ssh);
+}
+
+/*
+ * Reconfigure the SSH backend.
+ * 
+ * Currently, this function does nothing very useful. In future,
+ * however, we could do some handy things with it. For example, we
+ * could make the port forwarding configurer active in the Change
+ * Settings box, and this routine could close down existing
+ * forwardings and open up new ones in response to changes.
+ */
+static void ssh_reconfig(void *handle, Config *cfg)
+{
+    Ssh ssh = (Ssh) handle;
+    ssh->cfg = *cfg;                  /* STRUCTURE COPY */
+}
+
 /*
  * Called to send data down the Telnet connection.
  */
@@ -5938,7 +6052,7 @@ static int ssh_send(void *handle, char *buf, int len)
     if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
        return 0;
 
-    ssh->protocol(ssh, buf, len, 0);
+    ssh->protocol(ssh, (unsigned char *)buf, len, 0);
 
     return ssh_sendbuffer(ssh);
 }
@@ -5994,7 +6108,7 @@ static void ssh_size(void *handle, int width, int height)
        ssh->size_needed = TRUE;       /* buffer for later */
        break;
       case SSH_STATE_SESSION:
-       if (!cfg.nopty) {
+       if (!ssh->cfg.nopty) {
            if (ssh->version == 1) {
                send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
                            PKT_INT, ssh->term_height,
@@ -6082,7 +6196,7 @@ void *new_sock_channel(void *handle, Socket s)
  * This is called when stdout/stderr (the entity to which
  * from_backend sends data) manages to clear some backlog.
  */
-void ssh_unthrottle(void *handle, int bufsize)
+static void ssh_unthrottle(void *handle, int bufsize)
 {
     Ssh ssh = (Ssh) handle;
     if (ssh->version == 1) {
@@ -6100,10 +6214,8 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
 {
     struct ssh_channel *c = (struct ssh_channel *)channel;
     Ssh ssh = c->ssh;
-    char buf[1024];
 
-    sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port);
-    logevent(buf);
+    logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
 
     if (ssh->version == 1) {
        send_packet(ssh, SSH1_MSG_PORT_OPEN,
@@ -6187,6 +6299,8 @@ extern int ssh_fallback_cmd(void *handle)
 
 Backend ssh_backend = {
     ssh_init,
+    ssh_free,
+    ssh_reconfig,
     ssh_send,
     ssh_sendbuffer,
     ssh_size,