New SSH bug flag, for 'can't handle SSH2_MSG_IGNORE'. Another user
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index 3eff2cf..029c78a 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -12,7 +12,9 @@
 #include "putty.h"
 #include "tree234.h"
 #include "ssh.h"
+#ifndef NO_GSSAPI
 #include "sshgss.h"
+#endif
 
 #ifndef FALSE
 #define FALSE 0
@@ -192,6 +194,7 @@ static const char *const ssh2_disconnect_reasons[] = {
 #define BUG_SSH2_REKEY                           64
 #define BUG_SSH2_PK_SESSIONID                   128
 #define BUG_SSH2_MAXPKT                                256
+#define BUG_CHOKES_ON_SSH2_IGNORE               512
 
 /*
  * Codes for terminal modes.
@@ -2009,7 +2012,8 @@ static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
 {
     int len;
     if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
-       ssh->deferred_len == 0 && !noignore) {
+       ssh->deferred_len == 0 && !noignore &&
+       !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
        /*
         * Interpose an SSH_MSG_IGNORE to ensure that user data don't
         * get encrypted with a known IV.
@@ -2139,7 +2143,8 @@ static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
         * unavailable, we don't do this trick at all, because we
         * gain nothing by it.)
         */
-       if (ssh->cscipher) {
+       if (ssh->cscipher &&
+           !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
            int stringlen, i;
 
            stringlen = (256 - ssh->deferred_len);
@@ -2506,6 +2511,15 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        ssh->remote_bugs |= BUG_SSH2_MAXPKT;
        logevent("We believe remote version ignores SSH-2 maximum packet size");
     }
+
+    if (ssh->cfg.sshbug_ignore2 == FORCE_ON) {
+       /*
+        * Servers that don't support SSH2_MSG_IGNORE. Currently,
+        * none detected automatically.
+        */
+       ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
+       logevent("We believe remote version has SSH-2 ignore bug");
+    }
 }
 
 /*
@@ -2851,6 +2865,8 @@ static int ssh_do_close(Ssh ssh, int notify_exit)
            del234(ssh->portfwds, pf); /* moving next one to index 0 */
            free_portfwd(pf);
        }
+       freetree234(ssh->portfwds);
+       ssh->portfwds = NULL;
     }
 
     return ret;
@@ -4425,12 +4441,19 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
 
            epfrec = add234(ssh->portfwds, pfrec);
            if (epfrec != pfrec) {
+               if (epfrec->status == DESTROY) {
+                   /*
+                    * We already have a port forwarding up and running
+                    * with precisely these parameters. Hence, no need
+                    * to do anything; simply re-tag the existing one
+                    * as KEEP.
+                    */
+                   epfrec->status = KEEP;
+               }
                /*
-                * We already have a port forwarding with precisely
-                * these parameters. Hence, no need to do anything;
-                * simply tag the existing one as KEEP.
+                * Anything else indicates that there was a duplicate
+                * in our input, which we'll silently ignore.
                 */
-               epfrec->status = KEEP;
                free_portfwd(pfrec);
            } else {
                pfrec->status = CREATE;
@@ -4994,10 +5017,10 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
        }
     }
 
-    if (ssh->cfg.x11_forward) {
+    if (ssh->cfg.x11_forward &&
+       (ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                         ssh->cfg.x11_auth, &ssh->cfg))) {
        logevent("Requesting X11 forwarding");
-       ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
-                                        ssh->cfg.x11_auth, &ssh->cfg);
        /*
         * Note that while we blank the X authentication data here, we don't
         * take any special action to blank the start of an X11 channel,
@@ -6659,11 +6682,13 @@ static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
         * wrap up and close the channel ourselves.
         */
        x11_close(c->u.x11.s);
+       c->u.x11.s = NULL;
        sshfwd_close(c);
     } else if (c->type == CHAN_AGENT) {
        sshfwd_close(c);
     } else if (c->type == CHAN_SOCKDATA) {
        pfd_close(c->u.pfd.s);
+       c->u.pfd.s = NULL;
        sshfwd_close(c);
     }
 }
@@ -7011,6 +7036,7 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
 
     if (typelen == 3 && !memcmp(type, "x11", 3)) {
        char *addrstr;
+       const char *x11err;
 
        ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
        addrstr = snewn(peeraddrlen+1, char);
@@ -7023,8 +7049,9 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
 
        if (!ssh->X11_fwd_enabled)
            error = "X11 forwarding is not enabled";
-       else if (x11_init(&c->u.x11.s, ssh->x11disp, c,
-                         addrstr, peerport, &ssh->cfg) != NULL) {
+       else if ((x11err = x11_init(&c->u.x11.s, ssh->x11disp, c,
+                                   addrstr, peerport, &ssh->cfg)) != NULL) {
+           logeventf(ssh, "Local X11 connection failed: %s", x11err);
            error = "Unable to open an X11 connection";
        } else {
            logevent("Opening X11 forward connection succeeded");
@@ -7154,8 +7181,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        int done_service_req;
        int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
        int tried_pubkey_config, done_agent;
+#ifndef NO_GSSAPI
        int can_gssapi;
        int tried_gssapi;
+#endif
        int kbd_inter_refused;
        int we_are_in;
        prompts_t *cur_prompt;
@@ -7179,11 +7208,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        int try_send;
        int num_env, env_left, env_ok;
        struct Packet *pktout;
+#ifndef NO_GSSAPI
        Ssh_gss_ctx gss_ctx;
        Ssh_gss_buf gss_buf;
        Ssh_gss_buf gss_rcvtok, gss_sndtok;
        Ssh_gss_name gss_srv_name;
        Ssh_gss_stat gss_stat;
+#endif
     };
     crState(do_ssh2_authconn_state);
 
@@ -7191,7 +7222,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
 
     s->done_service_req = FALSE;
     s->we_are_in = FALSE;
+#ifndef NO_GSSAPI
     s->tried_gssapi = FALSE;
+#endif
 
     if (!ssh->cfg.ssh_no_userauth) {
        /*
@@ -8093,23 +8126,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    ssh_pkt_getstring(pktin, &lang, &lang_len);
                    s->cur_prompt = new_prompts(ssh->frontend);
                    s->cur_prompt->to_server = TRUE;
-                   if (name_len) {
-                       /* FIXME: better prefix to distinguish from
-                        * local prompts? */
-                       s->cur_prompt->name =
-                           dupprintf("SSH server: %.*s", name_len, name);
-                       s->cur_prompt->name_reqd = TRUE;
-                   } else {
-                       s->cur_prompt->name =
-                           dupstr("SSH server authentication");
-                       s->cur_prompt->name_reqd = FALSE;
-                   }
-                   /* FIXME: ugly to print "Using..." in prompt _every_
-                    * time round. Can this be done more subtly? */
-                   s->cur_prompt->instruction =
-                       dupprintf("Using keyboard-interactive authentication.%s%.*s",
-                                 inst_len ? "\n" : "", inst_len, inst);
-                   s->cur_prompt->instr_reqd = TRUE;
 
                    /*
                     * Get any prompt(s) from the packet.
@@ -8133,6 +8149,33 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                                   echo, SSH_MAX_PASSWORD_LEN);
                    }
 
+                   if (name_len) {
+                       /* FIXME: better prefix to distinguish from
+                        * local prompts? */
+                       s->cur_prompt->name =
+                           dupprintf("SSH server: %.*s", name_len, name);
+                       s->cur_prompt->name_reqd = TRUE;
+                   } else {
+                       s->cur_prompt->name =
+                           dupstr("SSH server authentication");
+                       s->cur_prompt->name_reqd = FALSE;
+                   }
+                   /* We add a prefix to try to make it clear that a prompt
+                    * has come from the server.
+                    * FIXME: ugly to print "Using..." in prompt _every_
+                    * time round. Can this be done more subtly? */
+                   /* Special case: for reasons best known to themselves,
+                    * some servers send k-i requests with no prompts and
+                    * nothing to display. Keep quiet in this case. */
+                   if (s->num_prompts || name_len || inst_len) {
+                       s->cur_prompt->instruction =
+                           dupprintf("Using keyboard-interactive authentication.%s%.*s",
+                                     inst_len ? "\n" : "", inst_len, inst);
+                       s->cur_prompt->instr_reqd = TRUE;
+                   } else {
+                       s->cur_prompt->instr_reqd = FALSE;
+                   }
+
                    /*
                      * Display any instructions, and get the user's
                      * response(s).
@@ -8550,7 +8593,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
        ssh2_msg_channel_open;
 
-    if (ssh->cfg.ssh_simple) {
+    if (ssh->mainchan && ssh->cfg.ssh_simple) {
        /*
         * This message indicates to the server that we promise
         * not to try to run any other channel in parallel with
@@ -8567,10 +8610,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     /*
      * Potentially enable X11 forwarding.
      */
-    if (ssh->mainchan && !ssh->ncmode && ssh->cfg.x11_forward) {
+    if (ssh->mainchan && !ssh->ncmode && ssh->cfg.x11_forward &&
+       (ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                         ssh->cfg.x11_auth, &ssh->cfg))) {
        logevent("Requesting X11 forwarding");
-       ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
-                                        ssh->cfg.x11_auth, &ssh->cfg);
        s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
        ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
        ssh2_pkt_addstring(s->pktout, "x11-req");
@@ -9395,8 +9438,10 @@ static const struct telnet_special *ssh_get_specials(void *handle)
     static const struct telnet_special ssh1_ignore_special[] = {
        {"IGNORE message", TS_NOP}
     };
-    static const struct telnet_special ssh2_transport_specials[] = {
+    static const struct telnet_special ssh2_ignore_special[] = {
        {"IGNORE message", TS_NOP},
+    };
+    static const struct telnet_special ssh2_rekey_special[] = {
        {"Repeat key exchange", TS_REKEY},
     };
     static const struct telnet_special ssh2_session_specials[] = {
@@ -9421,7 +9466,8 @@ static const struct telnet_special *ssh_get_specials(void *handle)
        {NULL, TS_EXITMENU}
     };
     /* XXX review this length for any changes: */
-    static struct telnet_special ssh_specials[lenof(ssh2_transport_specials) +
+    static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
+                                             lenof(ssh2_rekey_special) +
                                              lenof(ssh2_session_specials) +
                                              lenof(specials_end)];
     Ssh ssh = (Ssh) handle;
@@ -9440,7 +9486,10 @@ static const struct telnet_special *ssh_get_specials(void *handle)
        if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
            ADD_SPECIALS(ssh1_ignore_special);
     } else if (ssh->version == 2) {
-       ADD_SPECIALS(ssh2_transport_specials);
+       if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
+           ADD_SPECIALS(ssh2_ignore_special);
+       if (!(ssh->remote_bugs & BUG_SSH2_REKEY))
+           ADD_SPECIALS(ssh2_rekey_special);
        if (ssh->mainchan)
            ADD_SPECIALS(ssh2_session_specials);
     } /* else we're not ready yet */
@@ -9490,9 +9539,11 @@ static void ssh_special(void *handle, Telnet_Special code)
            if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
                send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
        } else {
-           pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
-           ssh2_pkt_addstring_start(pktout);
-           ssh2_pkt_send_noqueue(ssh, pktout);
+           if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
+               pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
+               ssh2_pkt_addstring_start(pktout);
+               ssh2_pkt_send_noqueue(ssh, pktout);
+           }
        }
     } else if (code == TS_REKEY) {
        if (!ssh->kex_in_progress && ssh->version == 2) {