- dtucker@cvs.openbsd.org 2010/01/11 01:39:46

[ssh_config channels.c ssh.1 channels.h ssh.c]
     Add a 'netcat mode' (ssh -W).  This connects stdio on the client to a
     single port forward on the server.  This allows, for example, using ssh as
     a ProxyCommand to route connections via intermediate servers.
     bz #1618, man page help from jmc@, ok markus@

ChangeLog

@@ -1,4 +1,13 @@
-20091210
+20100111
+ - (dtucker) OpenBSD CVS Sync
+   - dtucker@cvs.openbsd.org 2010/01/11 01:39:46
+     [ssh_config channels.c ssh.1 channels.h ssh.c]
+     Add a 'netcat mode' (ssh -W).  This connects stdio on the client to a
+     single port forward on the server.  This allows, for example, using ssh as
+     a ProxyCommand to route connections via intermediate servers.
+     bz #1618, man page help from jmc@, ok markus@
+
+20100110
  - (dtucker) [configure.ac misc.c readconf.c servconf.c ssh-keyscan.c]
    Remove hacks add for RoutingDomain in preparation for its removal.
  - (dtucker) OpenBSD CVS Sync
@@ -22,7 +31,7 @@
      [auth.c]
      Output a debug if we can't open an existing keyfile.  bz#1694, ok djm@
 
-20091209
+20100109
  - (dtucker) Wrap use of IPPROTO_IPV6 in an ifdef for platforms that don't
    have it.
  - (dtucker) [defines.h] define PRIu64 for platforms that don't have it.
@@ -59,7 +68,7 @@
      dying.  bz#1692, patch from Colin Watson via Ubuntu.
  - (dtucker) [defines.h] Remove now-undeeded PRIu64 define.
 
-20091208
+20100108
  - (dtucker) OpenBSD CVS Sync
    - andreas@cvs.openbsd.org 2009/10/24 11:11:58
      [roaming.h]

channels.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.300 2010/01/09 23:04:13 dtucker Exp $ */
+/* $OpenBSD: channels.c,v 1.301 2010/01/11 01:39:46 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1217,6 +1217,35 @@ channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
 	return 1;
 }
 
+Channel *
+channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
+{
+	Channel *c;
+	int in, out;
+
+	debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
+	    port_to_connect);
+
+	in = dup(STDIN_FILENO);
+	out = dup(STDOUT_FILENO);
+	if (in < 0 || out < 0)
+		fatal("channel_connect_stdio_fwd: dup() in/out failed");
+
+	c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
+	    -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
+	    0, "stdio-forward", /*nonblock*/0);
+
+	c->path = xstrdup(host_to_connect);
+	c->host_port = port_to_connect;
+	c->listening_port = 0;
+	c->force_drain = 1;
+
+	channel_register_fds(c, in, out, -1, 0, 1, 0);
+	port_open_helper(c, "direct-tcpip");
+
+	return c;
+}
+
 /* dynamic port forwarding */
 static void
 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)

channels.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.101 2010/01/09 23:04:13 dtucker Exp $ */
+/* $OpenBSD: channels.h,v 1.102 2010/01/11 01:39:46 dtucker Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -243,6 +243,7 @@ void	 channel_clear_adm_permitted_opens(void);
 void 	 channel_print_adm_permitted_opens(void);
 int      channel_input_port_forward_request(int, int);
 Channel	*channel_connect_to(const char *, u_short, char *, char *);
+Channel	*channel_connect_stdio_fwd(const char*, u_short);
 Channel	*channel_connect_by_listen_address(u_short, char *, char *);
 int	 channel_request_remote_forwarding(const char *, u_short,
 	     const char *, u_short);

ssh.1

@@ -34,8 +34,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: ssh.1,v 1.289 2010/01/09 23:04:13 dtucker Exp $
-.Dd $Mdocdate: January 9 2010 $
+.\" $OpenBSD: ssh.1,v 1.290 2010/01/11 01:39:46 dtucker Exp $
+.Dd $Mdocdate: January 11 2010 $
 .Dt SSH 1
 .Os
 .Sh NAME
@@ -77,12 +77,11 @@
 .Sm on
 .Oc
 .Op Fl S Ar ctl_path
-.Bk -words
+.Op Fl W Ar host : Ns Ar port
 .Oo Fl w Ar local_tun Ns
 .Op : Ns Ar remote_tun Oc
 .Oo Ar user Ns @ Oc Ns Ar hostname
 .Op Ar command
-.Ek
 .Sh DESCRIPTION
 .Nm
 (SSH client) is a program for logging into a remote machine and for
@@ -594,6 +593,19 @@ Multiple
 .Fl v
 options increase the verbosity.
 The maximum is 3.
+.It Fl W Ar host : Ns Ar port
+Requests that standard input and output on the client be forwarded to
+.Ar host
+on
+.Ar port
+over the secure channel.
+Implies
+.Fl N ,
+.Fl T ,
+.Cm ExitOnForwardFailure
+and
+.Cm ClearAllForwardings
+and works with Protocol version 2 only.
 .It Fl w Xo
 .Ar local_tun Ns Op : Ns Ar remote_tun
 .Xc

ssh.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.330 2010/01/09 23:04:13 dtucker Exp $ */
+/* $OpenBSD: ssh.c,v 1.331 2010/01/11 01:39:46 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -133,6 +133,10 @@ int stdin_null_flag = 0;
  */
 int fork_after_authentication_flag = 0;
 
+/* forward stdio to remote host and port */
+char *stdio_forward_host = NULL;
+int stdio_forward_port = 0;
+
 /*
  * General data structure for command line options and options configurable
  * in configuration files.  See readconf.h.
@@ -186,7 +190,8 @@ usage(void)
 "           [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
-"           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
+"           [-W host:port] [-w local_tun[:remote_tun]]\n"
+"           [user@]hostname [command]\n"
 	);
 	exit(255);
 }
@@ -276,7 +281,7 @@ main(int ac, char **av)
 
  again:
 	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
-	    "ACD:F:I:KL:MNO:PR:S:TVw:XYy")) != -1) {
+	    "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
 		switch (opt) {
 		case '1':
 			options.protocol = SSH_PROTO_1;
@@ -389,6 +394,22 @@ main(int ac, char **av)
 				exit(255);
 			}
 			break;
+		case 'W':
+			if (parse_forward(&fwd, optarg, 1, 0)) {
+				stdio_forward_host = fwd.listen_host;
+				stdio_forward_port = fwd.listen_port;
+				xfree(fwd.connect_host);
+			} else {
+				fprintf(stderr,
+				    "Bad stdio forwarding specification '%s'\n",
+				    optarg);
+				exit(255);
+			}
+			no_tty_flag = 1;
+			no_shell_flag = 1;
+			options.clear_forwardings = 1;
+			options.exit_on_forward_failure = 1;
+			break;
 		case 'q':
 			options.log_level = SYSLOG_LEVEL_QUIET;
 			break;
@@ -870,12 +891,42 @@ ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
 	}
 }
 
+static void
+client_cleanup_stdio_fwd(int id, void *arg)
+{
+	debug("stdio forwarding: done");
+	cleanup_exit(0);
+}
+
+static int
+client_setup_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
+{
+	Channel *c;
+
+	debug3("client_setup_stdio_fwd %s:%d", host_to_connect,
+	    port_to_connect);
+	if ((c = channel_connect_stdio_fwd(host_to_connect, port_to_connect))
+	    == NULL)
+		return 0;
+	channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
+	return 1;
+}
+
 static void
 ssh_init_forwarding(void)
 {
 	int success = 0;
 	int i;
 
+	if (stdio_forward_host != NULL) {
+		if (!compat20) {
+			fatal("stdio forwarding require Protocol 2");
+		}
+		if (!client_setup_stdio_fwd(stdio_forward_host,
+		    stdio_forward_port))
+			fatal("Failed to connect in stdio forward mode.");
+	}
+
 	/* Initiate local TCP/IP port forwardings. */
 	for (i = 0; i < options.num_local_forwards; i++) {
 		debug("Local connections to %.200s:%d forwarded to remote "

ssh_config

@@ -1,4 +1,4 @@
-#	$OpenBSD: ssh_config,v 1.25 2009/02/17 01:28:32 djm Exp $
+#	$OpenBSD: ssh_config,v 1.26 2010/01/11 01:39:46 dtucker Exp $
 
 # This is the ssh client system-wide configuration file.  See
 # ssh_config(5) for more information.  This file provides defaults for
@@ -44,3 +44,4 @@
 #   TunnelDevice any:any
 #   PermitLocalCommand no
 #   VisualHostKey no
+#   ProxyCommand ssh -q -W %h:%p gateway.example.com