- dtucker@cvs.openbsd.org 2010/01/12 01:31:05

[openssh.git] / mux.c

diff --git a/mux.c b/mux.c
index efc3840cbbf5b509729b124b9335f51d6f2f47d2..239edd5f5e36737cb1aa5c7ba3c984c208b632c6 100644 (file)
--- a/mux.c
+++ b/mux.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mux.c,v 1.2 2008/06/12 03:40:52 djm Exp $ */
+/* $OpenBSD: mux.c,v 1.9 2010/01/09 05:04:24 djm Exp $ */
 /*
  * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
  *
@@ -30,7 +30,10 @@
  *   4. ExitOnForwardingFailure (after #3 obviously)
  *   5. Maybe extension mechanisms for multi-X11/multi-agent forwarding
  *   6. Document the mux mini-protocol somewhere.
- *   6. Support ~^Z in mux slaves.
+ *   7. Support ~^Z in mux slaves.
+ *   8. Inspect or control sessions in master.
+ *   9. If we ever support the "signal" channel request, send signals on
+ *      sessions in master.
  */
 
 #include <sys/types.h>
@@ -79,10 +82,11 @@
 
 /* from ssh.c */
 extern int tty_flag;
+extern int force_tty_flag;
 extern Options options;
 extern int stdin_null_flag;
 extern char *host;
-int subsystem_flag;
+extern int subsystem_flag;
 extern Buffer command;
 
 /* Context for session open confirmation callback */
@@ -141,10 +145,16 @@ 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);
@@ -433,6 +443,7 @@ muxserver_accept_control(void)
        if (cctx->want_tty && escape_char != 0xffffffff) {
                channel_register_filter(c->self,
                    client_simple_escape_filter, NULL,
+                   client_filter_cleanup,
                    client_new_escape_filter_ctx((int)escape_char));
        }
 
@@ -496,7 +507,7 @@ 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;
@@ -567,17 +578,38 @@ 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: Did not receive reply from master", __func__);
+               goto muxerr;
+       }
+       if (buffer_get_char(&m) != SSHMUX_VER) {
+               error("%s: Master replied with 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);
@@ -621,13 +653,22 @@ 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);
@@ -643,7 +684,7 @@ muxclient(const char *path)
        signal(SIGWINCH, control_client_sigrelay);
 
        if (tty_flag)
-               enter_raw_mode();
+               enter_raw_mode(force_tty_flag);
 
        /*
         * Stick around until the controlee closes the client_fd.
@@ -668,10 +709,10 @@ muxclient(const char *path)
        }
 
        close(sock);
-       leave_raw_mode();
+       leave_raw_mode(force_tty_flag);
        if (i > (int)sizeof(int))
                fatal("%s: master returned too much data (%d > %lu)",
-                   __func__, i, sizeof(int));
+                   __func__, i, (u_long)sizeof(int));
        if (muxclient_terminate) {
                debug2("Exiting on signal %d", muxclient_terminate);
                exitval[0] = 255;