- djm@cvs.openbsd.org 2012/08/17 01:22:56

     [kex.c]
     add some comments about better handling first-KEX-follows notifications
     from the server. Nothing uses these right now. No binary change

2 files changed, 17 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index bdaaa0ae3..dd2877436 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,10 @@
      Force a clean shutdown of ControlMaster client sessions when the ~. escape
      sequence is used.  This means that ~. should now work in mux clients even
      if the server is no longer responding.  Found by tedu, ok djm.
+   - djm@cvs.openbsd.org 2012/08/17 01:22:56
+     [kex.c]
+     add some comments about better handling first-KEX-follows notifications
+     from the server. Nothing uses these right now. No binary change
 
 20120830
  - (dtucker) [moduli] Import new moduli file.
diff --git a/kex.c b/kex.c
index c65e28f94..f77b3c925 100644
--- a/kex.c
+++ b/kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.c,v 1.86 2010/09/22 05:01:29 djm Exp $ */
+/* $OpenBSD: kex.c,v 1.87 2012/08/17 01:22:56 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
@@ -242,8 +242,18 @@ kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
                 packet_get_char();
         for (i = 0; i < PROPOSAL_MAX; i++)
                 xfree(packet_get_string(NULL));
-        (void) packet_get_char();
-        (void) packet_get_int();
+        /*
+         * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported
+         * KEX method has the server move first, but a server might be using
+         * a custom method or one that we otherwise don't support. We should
+         * be prepared to remember first_kex_follows here so we can eat a
+         * packet later.
+         * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means
+         * for cases where the server *doesn't* go first. I guess we should
+         * ignore it when it is set for these cases, which is what we do now.
+         */
+        (void) packet_get_char();       /* first_kex_follows */
+        (void) packet_get_int();        /* reserved */
         packet_check_eom();
 
         kex_kexinit_finish(kex);