upstream: 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@

OpenBSD-Commit-ID: c5064d285c2851f773dd736a2c342aa384fbf713

1 files changed, 9 insertions, 2 deletions

diff --git a/readconf.c b/readconf.c
index 10b57bd45..56bff850a 100644
--- a/readconf.c
+++ b/readconf.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: readconf.c,v 1.281 2017/12/05 23:59:47 dtucker Exp $ */
+/* $OpenBSD: readconf.c,v 1.282 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
@@ -156,7 +156,7 @@ typedef enum {
         oPubkeyAuthentication,
         oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias,
         oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication,
-        oHostKeyAlgorithms, oBindAddress, oPKCS11Provider,
+        oHostKeyAlgorithms, oBindAddress, oBindInterface, oPKCS11Provider,
         oClearAllForwardings, oNoHostAuthenticationForLocalhost,
         oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
         oAddressFamily, oGssAuthentication, oGssDelegateCreds,
@@ -266,6 +266,7 @@ static struct {
         { "preferredauthentications", oPreferredAuthentications },
         { "hostkeyalgorithms", oHostKeyAlgorithms },
         { "bindaddress", oBindAddress },
+        { "bindinterface", oBindInterface },
         { "clearallforwardings", oClearAllForwardings },
         { "enablesshkeysign", oEnableSSHKeysign },
         { "verifyhostkeydns", oVerifyHostKeyDNS },
@@ -1099,6 +1100,10 @@ parse_char_array:
                 charptr = &options->bind_address;
                 goto parse_string;
 
+        case oBindInterface:
+                charptr = &options->bind_interface;
+                goto parse_string;
+
         case oPKCS11Provider:
                 charptr = &options->pkcs11_provider;
                 goto parse_string;
@@ -1800,6 +1805,7 @@ initialize_options(Options * options)
         options->log_level = SYSLOG_LEVEL_NOT_SET;
         options->preferred_authentications = NULL;
         options->bind_address = NULL;
+        options->bind_interface = NULL;
         options->pkcs11_provider = NULL;
         options->enable_ssh_keysign = - 1;
         options->no_host_authentication_for_localhost = - 1;
@@ -2509,6 +2515,7 @@ dump_client_config(Options *o, const char *host)
 
         /* String options */
         dump_cfg_string(oBindAddress, o->bind_address);
+        dump_cfg_string(oBindInterface, o->bind_interface);
         dump_cfg_string(oCiphers, o->ciphers ? o->ciphers : KEX_CLIENT_ENCRYPT);
         dump_cfg_string(oControlPath, o->control_path);
         dump_cfg_string(oHostKeyAlgorithms, o->hostkeyalgorithms);