upstream: make failures when establishing "Tunnel" forwarding terminate

the connection when ExitOnForwardFailure is enabled; bz3116; ok dtucker

OpenBSD-Commit-ID: ef4b4808de0a419c17579b1081da768625c1d735

1 files changed, 39 insertions, 23 deletions

diff --git a/ssh.c b/ssh.c
index 470d9b7e6..d99a245a4 100644
--- a/ssh.c
+++ b/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.522 2020/04/03 02:27:12 dtucker Exp $ */
+/* $OpenBSD: ssh.c,v 1.523 2020/04/03 02:40:32 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -197,7 +197,7 @@ struct sshbuf *command;
 int subsystem_flag = 0;
 
 /* # of replies received for global requests */
-static int remote_forward_confirms_received = 0;
+static int forward_confirms_pending = -1;
 
 /* mux.c */
 extern int muxserver_sock;
@@ -1673,6 +1673,16 @@ fork_postauth(void)
                 fatal("daemon() failed: %.200s", strerror(errno));
 }
 
+static void
+forwarding_success(void)
+{
+        if (forward_confirms_pending > 0 && --forward_confirms_pending == 0) {
+                debug("All forwarding requests processed");
+                if (fork_after_authentication_flag)
+                        fork_postauth();
+        }
+}
+
 /* Callback for remote forward global requests */
 static void
 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
@@ -1732,11 +1742,7 @@ ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
                                     "for listen port %d", rfwd->listen_port);
                 }
         }
-        if (++remote_forward_confirms_received == options.num_remote_forwards) {
-                debug("All remote forwarding requests processed");
-                if (fork_after_authentication_flag)
-                        fork_postauth();
-        }
+        forwarding_success();
 }
 
 static void
@@ -1754,6 +1760,19 @@ ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
 }
 
 static void
+ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
+{
+        if (!success) {
+                error("Tunnel forwarding failed");
+                if (options.exit_on_forward_failure)
+                        cleanup_exit(255);
+        }
+
+        debug("%s: tunnel forward established, id=%d", __func__, id);
+        forwarding_success();
+}
+
+static void
 ssh_init_stdio_forwarding(struct ssh *ssh)
 {
         Channel *c;
@@ -1816,32 +1835,29 @@ ssh_init_forwarding(struct ssh *ssh, char **ifname)
                     options.remote_forwards[i].connect_path :
                     options.remote_forwards[i].connect_host,
                     options.remote_forwards[i].connect_port);
-                options.remote_forwards[i].handle =
+                if ((options.remote_forwards[i].handle =
                     channel_request_remote_forwarding(ssh,
-                    &options.remote_forwards[i]);
-                if (options.remote_forwards[i].handle < 0) {
-                        if (options.exit_on_forward_failure)
-                                fatal("Could not request remote forwarding.");
-                        else
-                                logit("Warning: Could not request remote "
-                                    "forwarding.");
-                } else {
+                    &options.remote_forwards[i])) >= 0) {
                         client_register_global_confirm(
                             ssh_confirm_remote_forward,
                             &options.remote_forwards[i]);
-                }
+                        forward_confirms_pending++;
+                } else if (options.exit_on_forward_failure)
+                        fatal("Could not request remote forwarding.");
+                else
+                        logit("Warning: Could not request remote forwarding.");
         }
 
         /* Initiate tunnel forwarding. */
         if (options.tun_open != SSH_TUNMODE_NO) {
                 if ((*ifname = client_request_tun_fwd(ssh,
                     options.tun_open, options.tun_local,
-                    options.tun_remote)) == NULL) {
-                        if (options.exit_on_forward_failure)
-                                fatal("Could not request tunnel forwarding.");
-                        else
-                                error("Could not request tunnel forwarding.");
-                }
+                    options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
+                        forward_confirms_pending++;
+                else if (options.exit_on_forward_failure)
+                        fatal("Could not request tunnel forwarding.");
+                else
+                        error("Could not request tunnel forwarding.");
         }
 }