- 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@

1 files changed, 54 insertions, 3 deletions

diff --git a/ssh.c b/ssh.c
index ee30e2b27..b86a764f6 100644
--- a/ssh.c
+++ b/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;
@@ -871,11 +892,41 @@ 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 "