--- openssh-4.7p1/ssh.c.masterrace	2008-03-06 13:55:11.000000000 +0000

+++ openssh-4.7p1/ssh.c	2008-03-06 13:55:19.000000000 +0000

@@ -1065,7 +1065,7 @@ client_global_request_reply_fwd(int type

 	}

 }

-static void

+static int

 ssh_control_listener(void)

 {

 	struct sockaddr_un addr;

@@ -1073,10 +1073,11 @@ ssh_control_listener(void)

 	int addr_len;

 	if (options.control_path == NULL ||

-	    options.control_master == SSHCTL_MASTER_NO)

-		return;

+	    options.control_master == SSHCTL_MASTER_NO ||

+	    control_fd != -1)

+		return 1;

-	debug("setting up multiplex master socket");

+	debug("trying to set up multiplex master socket");

 	memset(&addr, '\0', sizeof(addr));

 	addr.sun_family = AF_UNIX;

@@ -1093,11 +1094,9 @@ ssh_control_listener(void)

 	old_umask = umask(0177);

 	if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {

 		control_fd = -1;

-		if (errno == EINVAL || errno == EADDRINUSE)

-			fatal("ControlSocket %s already exists",

-			    options.control_path);

-		else

+		if (errno != EINVAL && errno != EADDRINUSE)

 			fatal("%s bind(): %s", __func__, strerror(errno));

+		return 0;

 	}

 	umask(old_umask);

@@ -1105,6 +1104,9 @@ ssh_control_listener(void)

 		fatal("%s listen(): %s", __func__, strerror(errno));

 	set_nonblock(control_fd);

+

+	debug("control master listening on %s", options.control_path);

+	return 1;

 }

 /* request pty/x11/agent/tcpfwd/shell for channel */

@@ -1196,7 +1198,9 @@ ssh_session2(void)

 	ssh_init_forwarding();

 	/* Start listening for multiplex clients */

-	ssh_control_listener();

+	if (!ssh_control_listener())

+		fatal("control master socket %s already exists",

+		      options.control_path);

  	/*

  	 * If we are the control master, and if control_persist is set,

@@ -1375,7 +1379,13 @@ control_client(const char *path)

 	switch (options.control_master) {

 	case SSHCTL_MASTER_AUTO:

 	case SSHCTL_MASTER_AUTO_ASK:

-		debug("auto-mux: Trying existing master");

+		/* see if we can create a control master socket

+		   to avoid a race between two auto clients */

+		if (mux_command == SSHMUX_COMMAND_OPEN &&

+		    ssh_control_listener())

+			return;

+		debug("trying to connect to control master socket %s",

+		    options.control_path);

 		/* FALLTHROUGH */

 	case SSHCTL_MASTER_NO:

 		break;

@@ -1522,6 +1532,8 @@ control_client(const char *path)

 	signal(SIGTERM, control_client_sighandler);

 	signal(SIGWINCH, control_client_sigrelay);

+	debug("connected to control master; waiting for exit");

+

 	if (tty_flag)

 		enter_raw_mode();