upstream commit

fatal() when a remote window update causes the window
 value to overflow. Reported by Georg Wicherski, ok markus@

Upstream-ID: ead397a9aceb3bf74ebfa5fcaf259d72e569f351

1 files changed, 6 insertions, 3 deletions

diff --git a/channels.c b/channels.c
index 8069cf1f9..3fe836aad 100644
--- a/channels.c
+++ b/channels.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.345 2015/06/30 05:23:25 djm Exp $ */
+/* $OpenBSD: channels.c,v 1.346 2015/06/30 05:25:07 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -2641,7 +2641,7 @@ channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
 {
         Channel *c;
         int id;
-        u_int adjust;
+        u_int adjust, tmp;
 
         if (!compat20)
                 return 0;
@@ -2657,7 +2657,10 @@ channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
         adjust = packet_get_int();
         packet_check_eom();
         debug2("channel %d: rcvd adjust %u", id, adjust);
-        c->remote_window += adjust;
+        if ((tmp = c->remote_window + adjust) < c->remote_window)
+                fatal("channel %d: adjust %u overflows remote window %u",
+                    id, adjust, c->remote_window);
+        c->remote_window = tmp;
         return 0;
 }