- djm@cvs.openbsd.org 2008/06/13 00:16:49

     [mux.c]
     fall back to creating a new TCP connection on most multiplexing errors
     (socket connect fail, invalid version, refused permittion, corrupted
     messages, etc.); bz #1329 ok dtucker@

1 files changed, 54 insertions, 18 deletions

diff --git a/mux.c b/mux.c
index 8f7bfb793..aaa3a4ee2 100644
--- a/mux.c
+++ b/mux.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mux.c,v 1.4 2008/06/12 15:19:17 djm Exp $ */
+/* $OpenBSD: mux.c,v 1.5 2008/06/13 00:16:49 djm Exp $ */
 /*
  * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
  *
@@ -144,10 +144,16 @@ muxserver_listen(void)
         old_umask = umask(0177);
         if (bind(muxserver_sock, (struct sockaddr *)&addr, addr_len) == -1) {
                 muxserver_sock = -1;
-                if (errno == EINVAL || errno == EADDRINUSE)
-                        fatal("ControlSocket %s already exists",
-                            options.control_path);
-                else
+                if (errno == EINVAL || errno == EADDRINUSE) {
+                        error("ControlSocket %s already exists, "
+                            "disabling multiplexing", options.control_path);
+                        close(muxserver_sock);
+                        muxserver_sock = -1;
+                        xfree(options.control_path);
+                        options.control_path = NULL;
+                        options.control_master = SSHCTL_MASTER_NO;
+                        return;
+                } else
                         fatal("%s bind(): %s", __func__, strerror(errno));
         }
         umask(old_umask);
@@ -500,7 +506,7 @@ muxclient(const char *path)
         Buffer m;
         char *term;
         extern char **environ;
-        u_int  flags;
+        u_int allowed, flags;
 
         if (muxclient_command == 0)
                 muxclient_command = SSHMUX_COMMAND_OPEN;
@@ -571,17 +577,38 @@ muxclient(const char *path)
         /* Send our command to server */
         buffer_put_int(&m, muxclient_command);
         buffer_put_int(&m, flags);
-        if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
-                fatal("%s: msg_send", __func__);
+        if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) {
+                error("%s: msg_send", __func__);
+ muxerr:
+                close(sock);
+                buffer_free(&m);
+                if (muxclient_command != SSHMUX_COMMAND_OPEN)
+                        cleanup_exit(255);
+                logit("Falling back to non-multiplexed connection");
+                xfree(options.control_path);
+                options.control_path = NULL;
+                options.control_master = SSHCTL_MASTER_NO;
+                return;
+        }
         buffer_clear(&m);
 
         /* Get authorisation status and PID of controlee */
-        if (ssh_msg_recv(sock, &m) == -1)
-                fatal("%s: msg_recv", __func__);
-        if (buffer_get_char(&m) != SSHMUX_VER)
-                fatal("%s: wrong version", __func__);
-        if (buffer_get_int(&m) != 1)
-                fatal("Connection to master denied");
+        if (ssh_msg_recv(sock, &m) == -1) {
+                error("%s: msg_recv", __func__);
+                goto muxerr;
+        }
+        if (buffer_get_char(&m) != SSHMUX_VER) {
+                error("%s: wrong version", __func__);
+                goto muxerr;
+        }
+        if (buffer_get_int_ret(&allowed, &m) != 0) {
+                error("%s: bad server reply", __func__);
+                goto muxerr;
+        }
+        if (allowed != 1) {
+                error("Connection to master denied");
+                goto muxerr;
+        }
         muxserver_pid = buffer_get_int(&m);
 
         buffer_clear(&m);
@@ -625,13 +652,22 @@ muxclient(const char *path)
                 fatal("unrecognised muxclient_command %d", muxclient_command);
         }
 
-        if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
-                fatal("%s: msg_send", __func__);
+        if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) {
+                error("%s: msg_send", __func__);
+                goto muxerr;
+        }
 
         if (mm_send_fd(sock, STDIN_FILENO) == -1 ||
             mm_send_fd(sock, STDOUT_FILENO) == -1 ||
-            mm_send_fd(sock, STDERR_FILENO) == -1)
-                fatal("%s: send fds failed", __func__);
+            mm_send_fd(sock, STDERR_FILENO) == -1) {
+                error("%s: send fds failed", __func__);
+                goto muxerr;
+        }
+
+        /*
+         * Mux errors are non-recoverable from this point as the master
+         * has ownership of the session now.
+         */
 
         /* Wait for reply, so master has a chance to gather ttymodes */
         buffer_clear(&m);