From ce07207c50a3d1f05d6dd49b5294282e59749787 Mon Sep 17 00:00:00 2001
From: Paul Jakma <paul@jakma.org>
Date: Sat, 6 Jan 2018 21:20:51 +0000
Subject: bgpd/security: fix infinite loop on certain invalid OPEN messages

Security issue: Quagga-2018-1975
See: https://www.quagga.net/security/Quagga-2018-1975.txt

* bgpd/bgp_packet.c: (bgp_capability_msg_parse) capability parser can infinite
  loop due to checks that issue 'continue' without bumping the input
  pointer.

--- a/bgpd/bgp_packet.c
+++ b/bgpd/bgp_packet.c
@@ -2251,7 +2251,8 @@ bgp_capability_msg_parse (struct peer *p
 
   end = pnt + length;
 
-  while (pnt < end)
+  /* XXX: Streamify this */
+  for (; pnt < end; pnt += hdr->length + 3)
     {      
       /* We need at least action, capability code and capability length. */
       if (pnt + 3 > end)
@@ -2339,7 +2340,6 @@ bgp_capability_msg_parse (struct peer *p
           zlog_warn ("%s unrecognized capability code: %d - ignored",
                      peer->host, hdr->code);
         }
-      pnt += hdr->length + 3;
     }
   return 0;
 }