- djm@cvs.openbsd.org 2014/02/26 20:18:37
[ssh.c]
bz#2205: avoid early hostname lookups unless canonicalisation is enabled;
ok dtucker@ markus@
diff --git a/ssh.c b/ssh.c
index b7dbea2..1e6cb90 100644
--- a/ssh.c
+++ b/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.400 2014/02/23 20:11:36 djm Exp $ */
+/* $OpenBSD: ssh.c,v 1.401 2014/02/26 20:18:37 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -899,12 +899,20 @@
addrs = resolve_canonicalize(&host, options.port);
/*
- * If canonicalization not requested, or if it failed then try to
- * resolve the bare hostname name using the system resolver's usual
- * search rules. Skip the lookup if a ProxyCommand is being used
- * unless the user has specifically requested canonicalisation.
+ * If CanonicalizePermittedCNAMEs have been specified but
+ * other canonicalization did not happen (by not being requested
+ * or by failing with fallback) then the hostname may still be changed
+ * as a result of CNAME following.
+ *
+ * Try to resolve the bare hostname name using the system resolver's
+ * usual search rules and then apply the CNAME follow rules.
+ *
+ * Skip the lookup if a ProxyCommand is being used unless the user
+ * has specifically requested canonicalisation for this case via
+ * CanonicalizeHostname=always
*/
- if (addrs == NULL && (option_clear_or_none(options.proxy_command) ||
+ if (addrs == NULL && options.num_permitted_cnames != 0 &&
+ (option_clear_or_none(options.proxy_command) ||
options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
if ((addrs = resolve_host(host, options.port, 1,
cname, sizeof(cname))) == NULL)
@@ -1000,6 +1008,16 @@
if (options.control_path != NULL)
muxclient(options.control_path);
+ /*
+ * If hostname canonicalisation was not enabled, then we may not
+ * have yet resolved the hostname. Do so now.
+ */
+ if (addrs == NULL && options.proxy_command == NULL) {
+ if ((addrs = resolve_host(host, options.port, 1,
+ cname, sizeof(cname))) == NULL)
+ cleanup_exit(255); /* resolve_host logs the error */
+ }
+
timeout_ms = options.connection_timeout * 1000;
/* Open a connection to the remote host. */