Attachment 1897 Details for Bug 1330 – /home/djm/ssh-controlpersist1.diff

[patch] /home/djm/ssh-controlpersist1.diff

ssh-controlpersist1.diff (text/plain), 13.62 KB, created by Damien Miller on 2010-07-13 14:18:16 AEST

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Creator: Damien Miller

Created: 2010-07-13 14:18:16 AEST

Size: 13.62 KB

patch

obsolete

>Index: clientloop.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/clientloop.c,v
>retrieving revision 1.221
>diff -u -p -r1.221 clientloop.c
>--- clientloop.c	25 Jun 2010 23:15:36 -0000	1.221
>+++ clientloop.c	13 Jul 2010 04:16:02 -0000
>@@ -137,6 +137,9 @@ static volatile sig_atomic_t received_si
> /* Flag indicating whether the user's terminal is in non-blocking mode. */
> static int in_non_blocking_mode = 0;
> 
>+/* Time when backgrounded control master using ControlPersist should exit */
>+static time_t control_persist_exit_time = 0;
>+
> /* Common data for the client loop code. */
> volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
> static int escape_char1;	/* Escape character. (proto1 only) */
>@@ -244,6 +247,34 @@ get_current_time(void)
> 	return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
> }
> 
>+/*
>+ * Sets control_persist_exit_time to the absolute time when the
>+ * backgrounded control master should exit due to expiry of the
>+ * ControlPersist timeout.  Sets it to 0 if we are not a backgrounded
>+ * control master process, or if there is no ControlPersist timeout.
>+ */
>+static void
>+set_control_persist_exit_time(void)
>+{
>+	if (muxserver_sock == -1 || !options.control_persist
>+	    || options.control_persist_timeout == 0)
>+		/* not using a ControlPersist timeout */
>+		control_persist_exit_time = 0;
>+	else if (channel_still_open()) {
>+		/* some client connections are still open */
>+		if (control_persist_exit_time > 0)
>+			debug2("%s: cancel scheduled exit", __func__);
>+		control_persist_exit_time = 0;
>+	} else if (control_persist_exit_time <= 0) {
>+		/* a client connection has recently closed */
>+		control_persist_exit_time = time(NULL) +
>+			(time_t)options.control_persist_timeout;
>+		debug2("%s: schedule exit in %d seconds", __func__,
>+		    options.control_persist_timeout);
>+	}
>+	/* else we are already counting down to the timeout */
>+}
>+
> #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
> void
> client_x11_get_proto(const char *display, const char *xauth_path,
>@@ -525,6 +556,7 @@ client_wait_until_can_do_something(fd_se
>     int *maxfdp, u_int *nallocp, int rekeying)
> {
> 	struct timeval tv, *tvp;
>+	int timeout_secs;
> 	int ret;
> 
> 	/* Add any selections by the channel mechanism. */
>@@ -568,16 +600,27 @@ client_wait_until_can_do_something(fd_se
> 	/*
> 	 * Wait for something to happen.  This will suspend the process until
> 	 * some selected descriptor can be read, written, or has some other
>-	 * event pending.
>+	 * event pending, or a timeout expires.
> 	 */
> 
>-	if (options.server_alive_interval == 0 || !compat20)
>+	timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */
>+	if (options.server_alive_interval > 0 && compat20)
>+		timeout_secs = options.server_alive_interval;
>+	set_control_persist_exit_time();
>+	if (control_persist_exit_time > 0) {
>+		timeout_secs = MIN(timeout_secs,
>+			control_persist_exit_time - time(NULL));
>+		if (timeout_secs < 0)
>+			timeout_secs = 0;
>+	}
>+	if (timeout_secs == INT_MAX)
> 		tvp = NULL;
> 	else {
>-		tv.tv_sec = options.server_alive_interval;
>+		tv.tv_sec = timeout_secs;
> 		tv.tv_usec = 0;
> 		tvp = &tv;
> 	}
>+
> 	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
> 	if (ret < 0) {
> 		char buf[100];
>@@ -1466,6 +1509,18 @@ client_loop(int have_pty, int escape_cha
> 		 */
> 		if (FD_ISSET(connection_out, writeset))
> 			packet_write_poll();
>+
>+		/*
>+		 * If we are a backgrounded control master, and the
>+		 * timeout has expired without any active client
>+		 * connections, then quit.
>+		 */
>+		if (control_persist_exit_time > 0) {
>+			if (time(NULL) >= control_persist_exit_time) {
>+				debug("ControlPersist timeout expired");
>+				break;
>+			}
>+		}
> 	}
> 	if (readset)
> 		xfree(readset);
>Index: readconf.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/readconf.c,v
>retrieving revision 1.186
>diff -u -p -r1.186 readconf.c
>--- readconf.c	25 Jun 2010 23:15:36 -0000	1.186
>+++ readconf.c	13 Jul 2010 04:16:02 -0000
>@@ -125,7 +125,8 @@ typedef enum {
> 	oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
> 	oAddressFamily, oGssAuthentication, oGssDelegateCreds,
> 	oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
>-	oSendEnv, oControlPath, oControlMaster, oHashKnownHosts,
>+	oSendEnv, oControlPath, oControlMaster, oControlPersist,
>+	oHashKnownHosts,
> 	oTunnel, oTunnelDevice, oLocalCommand, oPermitLocalCommand,
> 	oVisualHostKey, oUseRoaming, oZeroKnowledgePasswordAuthentication,
> 	oDeprecated, oUnsupported
>@@ -222,6 +223,7 @@ static struct {
> 	{ "sendenv", oSendEnv },
> 	{ "controlpath", oControlPath },
> 	{ "controlmaster", oControlMaster },
>+	{ "controlpersist", oControlPersist },
> 	{ "hashknownhosts", oHashKnownHosts },
> 	{ "tunnel", oTunnel },
> 	{ "tunneldevice", oTunnelDevice },
>@@ -878,6 +880,30 @@ parse_int:
> 			*intptr = value;
> 		break;
> 
>+	case oControlPersist:
>+		/* no/false/yes/true, or a time spec */
>+		intptr = &options->control_persist;
>+		arg = strdelim(&s);
>+		if (!arg || *arg == '\0')
>+			fatal("%.200s line %d: Missing ControlPersist"
>+			    " argument.", filename, linenum);
>+		value = 0;
>+		value2 = 0;	/* timeout */
>+		if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
>+			value = 0;
>+		else if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
>+			value = 1;
>+		else if ((value2 = convtime(arg)) >= 0)
>+			value = 1;
>+		else
>+			fatal("%.200s line %d: Bad ControlPersist argument.",
>+			    filename, linenum);
>+		if (*activep && *intptr == -1) {
>+			*intptr = value;
>+			options->control_persist_timeout = value2;
>+		}
>+		break;
>+
> 	case oHashKnownHosts:
> 		intptr = &options->hash_known_hosts;
> 		goto parse_flag;
>@@ -1079,6 +1105,8 @@ initialize_options(Options * options)
> 	options->num_send_env = 0;
> 	options->control_path = NULL;
> 	options->control_master = -1;
>+	options->control_persist = -1;
>+	options->control_persist_timeout = 0;
> 	options->hash_known_hosts = -1;
> 	options->tun_open = -1;
> 	options->tun_local = -1;
>@@ -1214,6 +1242,10 @@ fill_default_options(Options * options)
> 		options->server_alive_count_max = 3;
> 	if (options->control_master == -1)
> 		options->control_master = 0;
>+	if (options->control_persist == -1) {
>+		options->control_persist = 0;
>+		options->control_persist_timeout = 0;
>+	}
> 	if (options->hash_known_hosts == -1)
> 		options->hash_known_hosts = 0;
> 	if (options->tun_open == -1)
>Index: readconf.h
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/readconf.h,v
>retrieving revision 1.85
>diff -u -p -r1.85 readconf.h
>--- readconf.h	25 Jun 2010 23:15:36 -0000	1.85
>+++ readconf.h	13 Jul 2010 04:16:02 -0000
>@@ -114,6 +114,8 @@ typedef struct {
> 
> 	char	*control_path;
> 	int	control_master;
>+	int     control_persist; /* ControlPersist flag */
>+	int     control_persist_timeout; /* ControlPersist timeout (seconds) */
> 
> 	int	hash_known_hosts;
> 
>Index: ssh.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/ssh.c,v
>retrieving revision 1.343
>diff -u -p -r1.343 ssh.c
>--- ssh.c	12 Jul 2010 22:41:13 -0000	1.343
>+++ ssh.c	13 Jul 2010 04:16:03 -0000
>@@ -119,6 +119,15 @@ int no_shell_flag = 0;
> int stdin_null_flag = 0;
> 
> /*
>+ * Flag indicating that the current process should be backgrounded and
>+ * a new slave launched in the foreground for ControlPersist.
>+ */
>+int need_controlpersist_detach = 0;
>+
>+/* Copies of flags for ControlPersist foreground slave */
>+int ostdin_null_flag, ono_shell_flag, ono_tty_flag, otty_flag;
>+
>+/*
>  * Flag indicating that ssh should fork after authentication.  This is useful
>  * so that the passphrase can be entered manually, and then ssh goes to the
>  * background.
>@@ -719,6 +728,8 @@ main(int ac, char **av)
> 		fatal("No ControlPath specified for \"-O\" command");
> 	if (options.control_path != NULL)
> 		muxclient(options.control_path);
>+		/* If muxclient() can connect to a master socket,
>+		 * then it doesn't return. */
> 
> 	timeout_ms = options.connection_timeout * 1000;
> 
>@@ -858,6 +869,50 @@ main(int ac, char **av)
> 	return exit_status;
> }
> 
>+static void
>+control_persist_detach(void)
>+{
>+	pid_t pid;
>+
>+	debug("%s: backgrounding master process", __func__);
>+
>+ 	/*
>+ 	 * master (current process) into the background, and make the
>+ 	 * foreground process a client of the backgrounded master.
>+ 	 */
>+	switch ((pid = fork())) {
>+	case -1:
>+		fatal("%s: fork: %s", __func__, strerror(errno));
>+	case 0:
>+		/* Child: master process continues mainloop */
>+ 		break;
>+ 	default:
>+		/* Parent: set up mux slave to connect to backgrounded master */
>+		debug2("%s: background process is %ld", __func__, (long)pid);
>+		stdin_null_flag = ostdin_null_flag;
>+		no_shell_flag = ono_shell_flag;
>+		no_tty_flag = ono_tty_flag;
>+		tty_flag = otty_flag;
>+ 		close(muxserver_sock);
>+ 		muxserver_sock = -1;
>+ 		muxclient(options.control_path);
>+		/* muxclient() doesn't return on success. */
>+ 		fatal("Failed to connect to new control master");
>+ 	}
>+}
>+
>+/* Do fork() after authentication. Used by "ssh -f" */
>+static void
>+fork_postauth(void)
>+{
>+	if (need_controlpersist_detach)
>+		control_persist_detach();
>+	debug("forking to background");
>+	fork_after_authentication_flag = 0;
>+	if (daemon(1, 1) < 0)
>+		fatal("daemon() failed: %.200s", strerror(errno));
>+}
>+
> /* Callback for remote forward global requests */
> static void
> ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
>@@ -885,12 +940,8 @@ ssh_confirm_remote_forward(int type, u_i
> 	}
> 	if (++remote_forward_confirms_received == options.num_remote_forwards) {
> 		debug("All remote forwarding requests processed");
>-		if (fork_after_authentication_flag) {
>-			fork_after_authentication_flag = 0;
>-			if (daemon(1, 1) < 0)
>-				fatal("daemon() failed: %.200s",
>-				    strerror(errno));
>-		}
>+		if (fork_after_authentication_flag)
>+			fork_postauth();
> 	}
> }
> 
>@@ -1134,12 +1185,13 @@ ssh_session(void)
> 	 * If requested and we are not interested in replies to remote
> 	 * forwarding requests, then let ssh continue in the background.
> 	 */
>-	if (fork_after_authentication_flag &&
>-	    (!options.exit_on_forward_failure ||
>-	    options.num_remote_forwards == 0)) {
>-		fork_after_authentication_flag = 0;
>-		if (daemon(1, 1) < 0)
>-			fatal("daemon() failed: %.200s", strerror(errno));
>+	if (fork_after_authentication_flag) {
>+		if (options.exit_on_forward_failure &&
>+		    options.num_remote_forwards > 0) {
>+			debug("deferring postauth fork until remote forward "
>+			    "confirmation received");
>+		} else
>+			fork_postauth();
> 	}
> 
> 	/*
>@@ -1262,6 +1314,31 @@ ssh_session2(void)
> 	/* XXX should be pre-session */
> 	ssh_init_forwarding();
> 
>+	/* Start listening for multiplex clients */
>+	muxserver_listen();
>+
>+ 	/*
>+	 * If we are in control persist mode, then prepare to background
>+	 * ourselves and have a foreground client attach as a control
>+	 * slave. NB. we must save copies of the flags that we override for
>+	 * the backgrounding, since we defer attachment of the slave until
>+	 * after the connection is fully established (in particular,
>+	 * async rfwd replies have been received for ExitOnForwardFailure).
>+	 */
>+ 	if (options.control_persist && muxserver_sock != -1) {
>+		ostdin_null_flag = stdin_null_flag;
>+		ono_shell_flag = no_shell_flag;
>+		ono_tty_flag = no_tty_flag;
>+		otty_flag = tty_flag;
>+ 		stdin_null_flag = 1;
>+ 		no_shell_flag = 1;
>+ 		no_tty_flag = 1;
>+ 		tty_flag = 0;
>+		if (!fork_after_authentication_flag)
>+			need_controlpersist_detach = 1;
>+		fork_after_authentication_flag = 1;
>+ 	}
>+
> 	if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
> 		id = ssh_session2_open();
> 
>@@ -1280,19 +1357,17 @@ ssh_session2(void)
> 	    options.permit_local_command)
> 		ssh_local_cmd(options.local_command);
> 
>-	/* Start listening for multiplex clients */
>-	muxserver_listen();
>-
> 	/*
> 	 * If requested and we are not interested in replies to remote
> 	 * forwarding requests, then let ssh continue in the background.
> 	 */
>-	if (fork_after_authentication_flag &&
>-	    (!options.exit_on_forward_failure ||
>-	    options.num_remote_forwards == 0)) {
>-		fork_after_authentication_flag = 0;
>-		if (daemon(1, 1) < 0)
>-			fatal("daemon() failed: %.200s", strerror(errno));
>+	if (fork_after_authentication_flag) {
>+		if (options.exit_on_forward_failure &&
>+		    options.num_remote_forwards > 0) {
>+			debug("deferring postauth fork until remote forward "
>+			    "confirmation received");
>+		} else
>+			fork_postauth();
> 	}
> 
> 	if (options.use_roaming)
>Index: ssh_config.5
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/ssh_config.5,v
>retrieving revision 1.136
>diff -u -p -r1.136 ssh_config.5
>--- ssh_config.5	12 Jul 2010 22:41:13 -0000	1.136
>+++ ssh_config.5	13 Jul 2010 04:16:03 -0000
>@@ -319,6 +319,28 @@ It is recommended that any
> used for opportunistic connection sharing include
> at least %h, %p, and %r.
> This ensures that shared connections are uniquely identified.
>+.It Cm ControlPersist
>+When used in conjunction with
>+.Cm ControlMaster ,
>+specifies that the master connection should remain open
>+in the background (waiting for future client connections)
>+after the initial client connection has been closed.
>+If set to
>+.Dq no ,
>+then the master connection will not be placed into the background,
>+and will close as soon as the initial client connection is closed.
>+If set to
>+.Dq yes ,
>+then the master connection will remain in the background indefinitely
>+(until killed or closed via a mechanism such as the
>+.Xr ssh 1
>+.Dq Fl O No exit
>+option).
>+If set to a time in seconds, or a time in any of the formats documented in
>+.Xr sshd_config 5 ,
>+then the backgrounded master connection will automatically terminate
>+after it has remained idle (with no client connections) for the
>+specified time.
> .It Cm DynamicForward
> Specifies that a TCP port on the local machine be forwarded
> over the secure channel, and the application

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