Add a configuration option for TCP keepalives (SO_KEEPALIVE), default off.
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index 4243a04..6c94ba4 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -322,6 +322,8 @@ 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);
+static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt);
+static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt);
 
 /*
  * Buffer management constants. There are several of these for
@@ -571,6 +573,7 @@ struct ssh_tag {
 
     void *frontend;
 
+    int ospeed, ispeed;                       /* temporaries */
     int term_width, term_height;
 
     tree234 *channels;                /* indexed by local id */
@@ -649,12 +652,18 @@ struct ssh_tag {
      * potentially reconfigure port forwardings etc in mid-session.
      */
     Config cfg;
+
+    /*
+     * Used to transfer data back from async agent callbacks.
+     */
+    void *agent_response;
+    int agent_response_len;
 };
 
 #define logevent(s) logevent(ssh->frontend, s)
 
 /* logevent, only printf-formatted. */
-static void logeventf(Ssh ssh, char *fmt, ...)
+static void logeventf(Ssh ssh, const char *fmt, ...)
 {
     va_list ap;
     char *buf;
@@ -848,7 +857,7 @@ static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     if (ssh->cipher)
        ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
 
-    st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
+    st->realcrc = crc32_compute(ssh->pktin.data, st->biglen - 4);
     st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
     if (st->gotcrc != st->realcrc) {
        bombout(("Incorrect CRC received on packet"));
@@ -860,9 +869,12 @@ static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     if (ssh->v1_compressing) {
        unsigned char *decompblk;
        int decomplen;
-       zlib_decompress_block(ssh->sc_comp_ctx,
-                             ssh->pktin.body - 1, ssh->pktin.length + 1,
-                             &decompblk, &decomplen);
+       if (!zlib_decompress_block(ssh->sc_comp_ctx,
+                                  ssh->pktin.body - 1, ssh->pktin.length + 1,
+                                  &decompblk, &decomplen)) {
+           bombout(("Zlib decompression encountered invalid data"));
+           crStop(0);
+       }
 
        if (ssh->pktin.maxlen < st->pad + decomplen) {
            ssh->pktin.maxlen = st->pad + decomplen;
@@ -1236,7 +1248,7 @@ static int s_wrpkt_prepare(Ssh ssh)
 
     for (i = 0; i < pad; i++)
        ssh->pktout.data[i + 4] = random_byte();
-    crc = crc32(ssh->pktout.data + 4, biglen - 4);
+    crc = crc32_compute(ssh->pktout.data + 4, biglen - 4);
     PUT_32BIT(ssh->pktout.data + biglen, crc);
     PUT_32BIT(ssh->pktout.data, len);
 
@@ -1769,7 +1781,8 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        (ssh->cfg.sshbug_ignore1 == 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")))) {
+         !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
+         !strcmp(imp, "OSU_1.4alpha3")))) {
        /*
         * These versions don't support SSH1_MSG_IGNORE, so we have
         * to use a different defence against password length
@@ -1781,7 +1794,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
        (ssh->cfg.sshbug_plainpw1 == AUTO &&
-        (!strcmp(imp, "Cisco-1.25")))) {
+        (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
        /*
         * These versions need a plain password sent; they can't
         * handle having a null and a random length of data after
@@ -1805,6 +1818,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
        (ssh->cfg.sshbug_hmac2 == AUTO &&
+        !wc_match("* VShell", imp) &&
         (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)))) {
@@ -1817,6 +1831,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
        (ssh->cfg.sshbug_derivekey2 == AUTO &&
+        !wc_match("* VShell", imp) &&
         (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
        /*
         * These versions have the key-derivation bug (failing to
@@ -2051,23 +2066,25 @@ static void ssh_do_close(Ssh ssh)
      * Now we must shut down any port and X forwardings going
      * through this connection.
      */
-    for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
-       switch (c->type) {
-         case CHAN_X11:
-           x11_close(c->u.x11.s);
-           break;
-         case CHAN_SOCKDATA:
-           pfd_close(c->u.pfd.s);
-           break;
+    if (ssh->channels) {
+       for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
+           switch (c->type) {
+             case CHAN_X11:
+               x11_close(c->u.x11.s);
+               break;
+             case CHAN_SOCKDATA:
+               pfd_close(c->u.pfd.s);
+               break;
+           }
+           del234(ssh->channels, c);
+           if (ssh->version == 2)
+               bufchain_clear(&c->v.v2.outbuffer);
+           sfree(c);
        }
-       del234(ssh->channels, c);
-       if (ssh->version == 2)
-           bufchain_clear(&c->v.v2.outbuffer);
-       sfree(c);
     }
 }
 
-static int ssh_closing(Plug plug, char *error_msg, int error_code,
+static int ssh_closing(Plug plug, const char *error_msg, int error_code,
                       int calling_back)
 {
     Ssh ssh = (Ssh) plug;
@@ -2075,7 +2092,7 @@ static int ssh_closing(Plug plug, char *error_msg, int error_code,
     if (error_msg) {
        /* A socket error has occurred. */
        logevent(error_msg);
-       connection_fatal(ssh->frontend, error_msg);
+       connection_fatal(ssh->frontend, "%s", error_msg);
     } else {
        /* Otherwise, the remote side closed the connection normally. */
     }
@@ -2110,8 +2127,8 @@ static void ssh_sent(Plug plug, int bufsize)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static char *connect_to_host(Ssh ssh, char *host, int port,
-                            char **realhost, int nodelay)
+static const char *connect_to_host(Ssh ssh, char *host, int port,
+                                  char **realhost, int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
        ssh_closing,
@@ -2121,7 +2138,7 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
     };
 
     SockAddr addr;
-    char *err;
+    const char *err;
 
     ssh->savedhost = snewn(1 + strlen(host), char);
     if (!ssh->savedhost)
@@ -2137,8 +2154,10 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
      */
     logeventf(ssh, "Looking up host \"%s\"", host);
     addr = name_lookup(host, port, realhost, &ssh->cfg);
-    if ((err = sk_addr_error(addr)) != NULL)
+    if ((err = sk_addr_error(addr)) != NULL) {
+       sk_addr_free(addr);
        return err;
+    }
 
     /*
      * Open socket.
@@ -2150,7 +2169,7 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
     }
     ssh->fn = &fn_table;
     ssh->s = new_connection(addr, *realhost, port,
-                           0, 1, nodelay, (Plug) ssh, &ssh->cfg);
+                           0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
     if ((err = sk_socket_error(ssh->s)) != NULL) {
        ssh->s = NULL;
        return err;
@@ -2281,6 +2300,44 @@ static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
     return 0;
 }
 
+static void ssh_agent_callback(void *sshv, void *reply, int replylen)
+{
+    Ssh ssh = (Ssh) sshv;
+
+    ssh->agent_response = reply;
+    ssh->agent_response_len = replylen;
+
+    if (ssh->version == 1)
+       do_ssh1_login(ssh, NULL, -1, 0);
+    else
+       do_ssh2_authconn(ssh, NULL, -1, 0);
+}
+
+static void ssh_agentf_callback(void *cv, void *reply, int replylen)
+{
+    struct ssh_channel *c = (struct ssh_channel *)cv;
+    Ssh ssh = c->ssh;
+    void *sentreply = reply;
+
+    if (!sentreply) {
+       /* Fake SSH_AGENT_FAILURE. */
+       sentreply = "\0\0\0\1\5";
+       replylen = 5;
+    }
+    if (ssh->version == 2) {
+       ssh2_add_channel_data(c, sentreply, replylen);
+       ssh2_try_send(c);
+    } else {
+       send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
+                   PKT_INT, c->remoteid,
+                   PKT_INT, replylen,
+                   PKT_DATA, sentreply, replylen,
+                   PKT_END);
+    }
+    if (reply)
+       sfree(reply);
+}
+
 /*
  * Handle the key exchange and user authentication phases.
  */
@@ -2479,6 +2536,22 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     ssh->crcda_ctx = crcda_make_context();
     logevent("Installing CRC compensation attack detector");
 
+    if (servkey.modulus) {
+       sfree(servkey.modulus);
+       servkey.modulus = NULL;
+    }
+    if (servkey.exponent) {
+       sfree(servkey.exponent);
+       servkey.exponent = NULL;
+    }
+    if (hostkey.modulus) {
+       sfree(hostkey.modulus);
+       hostkey.modulus = NULL;
+    }
+    if (hostkey.exponent) {
+       sfree(hostkey.exponent);
+       hostkey.exponent = NULL;
+    }
     crWaitUntil(ispkt);
 
     if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
@@ -2546,7 +2619,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
     if (!filename_is_null(ssh->cfg.keyfile)) {
        if (!rsakey_pubblob(&ssh->cfg.keyfile,
-                           &s->publickey_blob, &s->publickey_bloblen))
+                           &s->publickey_blob, &s->publickey_bloblen, NULL))
            s->publickey_blob = NULL;
     } else
        s->publickey_blob = NULL;
@@ -2567,7 +2640,19 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            /* Request the keys held by the agent. */
            PUT_32BIT(s->request, 1);
            s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
-           agent_query(s->request, 5, &r, &s->responselen);
+           if (!agent_query(s->request, 5, &r, &s->responselen,
+                            ssh_agent_callback, ssh)) {
+               do {
+                   crReturn(0);
+                   if (ispkt) {
+                       bombout(("Unexpected data from server while waiting"
+                                " for agent response"));
+                       crStop(0);
+                   }
+               } while (ispkt || inlen > 0);
+               r = ssh->agent_response;
+               s->responselen = ssh->agent_response_len;
+           }
            s->response = (unsigned char *) r;
            if (s->response && s->responselen >= 5 &&
                s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
@@ -2629,9 +2714,23 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        memcpy(q, s->session_id, 16);
                        q += 16;
                        PUT_32BIT(q, 1);        /* response format */
-                       agent_query(agentreq, len + 4, &vret, &retlen);
+                       if (!agent_query(agentreq, len + 4, &vret, &retlen,
+                                        ssh_agent_callback, ssh)) {
+                           sfree(agentreq);
+                           do {
+                               crReturn(0);
+                               if (ispkt) {
+                                   bombout(("Unexpected data from server"
+                                            " while waiting for agent"
+                                            " response"));
+                                   crStop(0);
+                               }
+                           } while (ispkt || inlen > 0);
+                           vret = ssh->agent_response;
+                           retlen = ssh->agent_response_len;
+                       } else
+                           sfree(agentreq);
                        ret = vret;
-                       sfree(agentreq);
                        if (ret) {
                            if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
                                logevent("Sending Pageant's response");
@@ -2669,6 +2768,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    if (s->authed)
                        break;
                }
+               sfree(s->response);
            }
            if (s->authed)
                break;
@@ -2806,11 +2906,15 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            s->tried_publickey = 1;
            
            {
-               int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
+               const char *error = NULL;
+               int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
+                                    &error);
                if (ret == 0) {
                    c_write_str(ssh, "Couldn't load private key from ");
                    c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
-                   c_write_str(ssh, ".\r\n");
+                   c_write_str(ssh, " (");
+                   c_write_str(ssh, error);
+                   c_write_str(ssh, ").\r\n");
                    continue;          /* go and try password */
                }
                if (ret == -1) {
@@ -2951,6 +3055,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    }
                    logevent("Sending password with camouflage packets");
                    ssh_pkt_defersend(ssh);
+                   sfree(randomstr);
                } 
                else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
                    /*
@@ -3216,6 +3321,7 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            } else {
                while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
                dport = dserv = -1;
+               ssh->portfwd_strptr++; /* eat the NUL and move to next one */
            }
            sport = atoi(sports);
            sserv = 0;
@@ -3296,11 +3402,19 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     }
 
     if (!ssh->cfg.nopty) {
+       /* Unpick the terminal-speed string. */
+       /* XXX perhaps we should allow no speeds to be sent. */
+       ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
+       sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
+       /* Send the pty request. */
        send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
                    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);
+                   PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */
+                   PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */
+                   PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */
+                   PKT_CHAR, 0, PKT_END);
        ssh->state = SSH_STATE_INTERMED;
        do {
            crReturnV;
@@ -3313,7 +3427,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            c_write_str(ssh, "Server refused to allocate pty\r\n");
            ssh->editing = ssh->echoing = 1;
        }
-       logevent("Allocated pty");
+       logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
+                 ssh->ospeed, ssh->ispeed);
     } else {
        ssh->editing = ssh->echoing = 1;
     }
@@ -3454,7 +3569,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                struct ssh_rportfwd pf;
                int hostsize, port;
                char host[256], buf[1024];
-               char *p, *h, *e;
+               char *p, *h;
+               const char *e;
                c = snew(struct ssh_channel);
                c->ssh = ssh;
 
@@ -3627,25 +3743,13 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                c->u.a.lensofar += l;
                            }
                            if (c->u.a.lensofar == c->u.a.totallen) {
-                               void *reply, *sentreply;
+                               void *reply;
                                int replylen;
-                               agent_query(c->u.a.message,
-                                           c->u.a.totallen, &reply,
-                                           &replylen);
-                               if (reply)
-                                   sentreply = reply;
-                               else {
-                                   /* Fake SSH_AGENT_FAILURE. */
-                                   sentreply = "\0\0\0\1\5";
-                                   replylen = 5;
-                               }
-                               send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
-                                           PKT_INT, c->remoteid,
-                                           PKT_INT, replylen,
-                                           PKT_DATA, sentreply, replylen,
-                                           PKT_END);
-                               if (reply)
-                                   sfree(reply);
+                               if (agent_query(c->u.a.message,
+                                               c->u.a.totallen,
+                                               &reply, &replylen,
+                                               ssh_agentf_callback, c))
+                                   ssh_agentf_callback(c, reply, replylen);
                                sfree(c->u.a.message);
                                c->u.a.lensofar = 0;
                            }
@@ -4262,6 +4366,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     if (ssh->sccomp->text_name)
        logeventf(ssh, "Initialised %s decompression",
                  ssh->sccomp->text_name);
+    freebn(s->f);
+    freebn(s->K);
+    if (ssh->kex == &ssh_diffiehellman_gex) {
+       freebn(s->g);
+       freebn(s->p);
+    }
 
     /*
      * If this is the first key exchange phase, we must pass the
@@ -4515,7 +4625,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            if (keytype == SSH_KEYTYPE_SSH2) {
                s->publickey_blob =
                    ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
-                                        &s->publickey_bloblen);
+                                        &s->publickey_bloblen, NULL);
            } else {
                char *msgbuf;
                logeventf(ssh, "Unable to use this key file (%s)",
@@ -4644,6 +4754,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
            s->method = 0;
            ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
+           s->need_pw = FALSE;
 
            /*
             * Most password/passphrase prompts will be
@@ -4671,7 +4782,19 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                /* Request the keys held by the agent. */
                PUT_32BIT(s->request, 1);
                s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
-               agent_query(s->request, 5, &r, &s->responselen);
+               if (!agent_query(s->request, 5, &r, &s->responselen,
+                                ssh_agent_callback, ssh)) {
+                   do {
+                       crReturnV;
+                       if (ispkt) {
+                           bombout(("Unexpected data from server while"
+                                    " waiting for agent response"));
+                           crStopV;
+                       }
+                   } while (ispkt || inlen > 0);
+                   r = ssh->agent_response;
+                   s->responselen = ssh->agent_response_len;
+               }
                s->response = (unsigned char *) r;
                if (s->response && s->responselen >= 5 &&
                    s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
@@ -4775,7 +4898,21 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        s->q += ssh->pktout.length - 5;
                        /* And finally the (zero) flags word. */
                        PUT_32BIT(s->q, 0);
-                       agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
+                       if (!agent_query(s->agentreq, s->len + 4,
+                                        &vret, &s->retlen,
+                                        ssh_agent_callback, ssh)) {
+                           do {
+                               crReturnV;
+                               if (ispkt) {
+                                   bombout(("Unexpected data from server"
+                                            " while waiting for agent"
+                                            " response"));
+                                   crStopV;
+                               }
+                           } while (ispkt || inlen > 0);
+                           vret = ssh->agent_response;
+                           s->retlen = ssh->agent_response_len;
+                       }
                        s->ret = vret;
                        sfree(s->agentreq);
                        if (s->ret) {
@@ -4797,6 +4934,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    if (s->authed)
                        continue;
                }
+               sfree(s->response);
            }
 
            if (!s->method && s->can_pubkey && s->publickey_blob
@@ -4819,7 +4957,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                pub_blob =
                    (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
                                                          &algorithm,
-                                                         &pub_blob_len);
+                                                         &pub_blob_len,
+                                                         NULL);
                if (pub_blob) {
                    ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
                    ssh2_pkt_addstring(ssh, s->username);
@@ -4853,9 +4992,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    } else {
                        s->need_pw = FALSE;
                    }
-                   c_write_str(ssh, "Authenticating with public key \"");
-                   c_write_str(ssh, comment);
-                   c_write_str(ssh, "\"\r\n");
+                   if (flags & FLAG_VERBOSE) {
+                       c_write_str(ssh, "Authenticating with public key \"");
+                       c_write_str(ssh, comment);
+                       c_write_str(ssh, "\"\r\n");
+                   }
                    s->method = AUTH_PUBLICKEY_FILE;
                }
            }
@@ -4996,14 +5137,18 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 * We have our passphrase. Now try the actual authentication.
                 */
                struct ssh2_userkey *key;
+               const char *error = NULL;
 
-               key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
+               key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
+                                       &error);
                if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
                    if (key == SSH2_WRONG_PASSPHRASE) {
                        c_write_str(ssh, "Wrong passphrase\r\n");
                        s->tried_pubkey_config = FALSE;
                    } else {
-                       c_write_str(ssh, "Unable to load private key\r\n");
+                       c_write_str(ssh, "Unable to load private key (");
+                       c_write_str(ssh, error);
+                       c_write_str(ssh, ")\r\n");
                        s->tried_pubkey_config = TRUE;
                    }
                    /* Send a spurious AUTH_NONE to return to the top. */
@@ -5065,6 +5210,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
                    ssh2_pkt_send(ssh);
                    s->type = AUTH_TYPE_PUBLICKEY;
+                   key->alg->freekey(key->data);
                }
            } else if (s->method == AUTH_PASSWORD) {
                /*
@@ -5312,6 +5458,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            } else {
                while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
                dport = dserv = -1;
+               ssh->portfwd_strptr++; /* eat the NUL and move to next one */
            }
            sport = atoi(sports);
            sserv = 0;
@@ -5448,6 +5595,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      * Now allocate a pty for the session.
      */
     if (!ssh->cfg.nopty) {
+       /* Unpick the terminal-speed string. */
+       /* XXX perhaps we should allow no speeds to be sent. */
+        ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
+       sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
+       /* Build the pty request. */
        ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);       /* recipient channel */
        ssh2_pkt_addstring(ssh, "pty-req");
@@ -5458,7 +5610,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        ssh2_pkt_adduint32(ssh, 0);            /* pixel width */
        ssh2_pkt_adduint32(ssh, 0);            /* pixel height */
        ssh2_pkt_addstring_start(ssh);
-       ssh2_pkt_addstring_data(ssh, "\0", 1);  /* TTY_OP_END, no special options */
+       ssh2_pkt_addbyte(ssh, 128);            /* TTY_OP_ISPEED */
+       ssh2_pkt_adduint32(ssh, ssh->ispeed);
+       ssh2_pkt_addbyte(ssh, 129);            /* TTY_OP_OSPEED */
+       ssh2_pkt_adduint32(ssh, ssh->ospeed);
+       ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END */
        ssh2_pkt_send(ssh);
        ssh->state = SSH_STATE_INTERMED;
 
@@ -5483,7 +5639,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            c_write_str(ssh, "Server refused to allocate pty\r\n");
            ssh->editing = ssh->echoing = 1;
        } else {
-           logevent("Allocated pty");
+           logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
+                     ssh->ospeed, ssh->ispeed);
        }
     } else {
        ssh->editing = ssh->echoing = 1;
@@ -5630,22 +5787,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                c->u.a.lensofar += l;
                            }
                            if (c->u.a.lensofar == c->u.a.totallen) {
-                               void *reply, *sentreply;
+                               void *reply;
                                int replylen;
-                               agent_query(c->u.a.message,
-                                           c->u.a.totallen, &reply,
-                                           &replylen);
-                               if (reply)
-                                   sentreply = reply;
-                               else {
-                                   /* Fake SSH_AGENT_FAILURE. */
-                                   sentreply = "\0\0\0\1\5";
-                                   replylen = 5;
-                               }
-                               ssh2_add_channel_data(c, sentreply, replylen);
-                               s->try_send = TRUE;
-                               if (reply)
-                                   sfree(reply);
+                               if (agent_query(c->u.a.message,
+                                               c->u.a.totallen,
+                                               &reply, &replylen,
+                                               ssh_agentf_callback, c))
+                                   ssh_agentf_callback(c, reply, replylen);
                                sfree(c->u.a.message);
                                c->u.a.lensofar = 0;
                            }
@@ -5921,8 +6069,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    if (realpf == NULL) {
                        error = "Remote port is not recognised";
                    } else {
-                       char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
-                                                realpf->dport, c, &ssh->cfg);
+                       const char *e = pfd_newconnect(&c->u.pfd.s,
+                                                      realpf->dhost,
+                                                      realpf->dport, c,
+                                                      &ssh->cfg);
                        logeventf(ssh, "Received remote port open request"
                                  " for %s:%d", realpf->dhost, realpf->dport);
                        if (e != NULL) {
@@ -6031,11 +6181,12 @@ 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)
+static const char *ssh_init(void *frontend_handle, void **backend_handle,
+                           Config *cfg,
+                           char *host, int port, char **realhost, int nodelay,
+                           int keepalive)
 {
-    char *p;
+    const char *p;
     Ssh ssh;
 
     ssh = snew(struct ssh_tag);
@@ -6117,7 +6268,7 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
 
     ssh->protocol = NULL;
 
-    p = connect_to_host(ssh, host, port, realhost, nodelay);
+    p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
     if (p != NULL)
        return p;
 
@@ -6140,10 +6291,18 @@ static void ssh_free(void *handle)
        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->cs_comp_ctx) {
+       if (ssh->cscomp)
+           ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
+       else
+           zlib_compress_cleanup(ssh->cs_comp_ctx);
+    }
+    if (ssh->sc_comp_ctx) {
+       if (ssh->sccomp)
+           ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
+       else
+           zlib_decompress_cleanup(ssh->sc_comp_ctx);
+    }
     if (ssh->kex_ctx)
        dh_cleanup(ssh->kex_ctx);
     sfree(ssh->savedhost);
@@ -6177,7 +6336,22 @@ static void ssh_free(void *handle)
     sfree(ssh->do_ssh1_login_state);
     sfree(ssh->do_ssh2_transport_state);
     sfree(ssh->do_ssh2_authconn_state);
-    
+    if (ssh->pktout.data) {
+       sfree(ssh->pktout.data);
+       ssh->pktout.data = NULL;
+    }
+    if (ssh->pktin.data) {
+       sfree(ssh->pktin.data);
+       ssh->pktin.data = NULL;
+    }
+    if (ssh->crcda_ctx) {
+       crcda_free_context(ssh->crcda_ctx);
+       ssh->crcda_ctx = NULL;
+    }
+    if (ssh->logctx) {
+       log_free(ssh->logctx);
+       ssh->logctx = NULL;
+    }
     if (ssh->s)
        ssh_do_close(ssh);
     sfree(ssh);