Add BindInterface ssh_config directive and -B command-line argument

to ssh(1) that directs it to bind its outgoing connection to the
address of the specified network interface.

BindInterface prefers to use addresses that aren't loopback or link-
local, but will fall back to those if no other addresses of the
required family are available on that interface.

Based on patch by Mike Manning in bz#2820, ok dtucker@

1 files changed, 12 insertions, 9 deletions

diff --git a/usr.bin/ssh/ssh.c b/usr.bin/ssh/ssh.c
index d3845dfb721..55cafe2bcb5 100644
--- a/usr.bin/ssh/ssh.c
+++ b/usr.bin/ssh/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.473 2018/02/13 03:36:56 djm Exp $ */
+/* $OpenBSD: ssh.c,v 1.474 2018/02/23 02:34:33 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -185,13 +185,13 @@ static void
 usage(void)
 {
 	fprintf(stderr,
-"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
-"           [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
-"           [-F configfile] [-I pkcs11] [-i identity_file]\n"
-"           [-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]\n"
-"           [-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]\n"
-"           [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
-"           destination [command]\n"
+"usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
+"           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
+"           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
+"           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
+"           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
+"           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
+"           [-w local_tun[:remote_tun]] destination [command]\n"
 	);
 	exit(255);
 }
@@ -632,7 +632,7 @@ main(int ac, char **av)
 
  again:
 	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
-	    "ACD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
+	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 		switch (opt) {
 		case '1':
 			fatal("SSH protocol v.1 is no longer supported");
@@ -942,6 +942,9 @@ main(int ac, char **av)
 		case 'b':
 			options.bind_address = optarg;
 			break;
+		case 'B':
+			options.bind_interface = optarg;
+			break;
 		case 'F':
 			config = optarg;
 			break;