upstream commit

Revise hostkeys@openssh.com hostkey learning extension.

The client will not ask the server to prove ownership of the private
halves of any hitherto-unseen hostkeys it offers to the client.

Allow UpdateHostKeys option to take an 'ask' argument to let the
user manually review keys offered.

ok markus@
diff --git a/readconf.h b/readconf.h
index 701b9c6..576b9e3 100644
--- a/readconf.h
+++ b/readconf.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: readconf.h,v 1.108 2015/01/30 11:43:14 djm Exp $ */
+/* $OpenBSD: readconf.h,v 1.109 2015/02/16 22:13:32 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -148,7 +148,7 @@
 
 	int	 fingerprint_hash;
 
-	int	 update_hostkeys;
+	int	 update_hostkeys; /* one of SSH_UPDATE_HOSTKEYS_* */
 
 	char	*hostbased_key_types;
 
@@ -174,6 +174,10 @@
 #define SSHCONF_USERCONF	2  /* user provided config file not system */
 #define SSHCONF_POSTCANON	4  /* After hostname canonicalisation */
 
+#define SSH_UPDATE_HOSTKEYS_NO	0
+#define SSH_UPDATE_HOSTKEYS_YES	1
+#define SSH_UPDATE_HOSTKEYS_ASK	2
+
 void     initialize_options(Options *);
 void     fill_default_options(Options *);
 void	 fill_default_options_for_canonicalization(Options *);