From 33e3f1029c9ec6c63e430ff51063a6301d4b2262 Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Mon, 25 Sep 2017 20:05:11 +0100
Subject: [PATCH 5/9] Security fix, CVE-2017-14494, Infoleak handling DHCPv6
 forwarded requests.

Fix information leak in DHCPv6. A crafted DHCPv6 packet can
cause dnsmasq to forward memory from outside the packet
buffer to a DHCPv6 server when acting as a relay.
---
 src/rfc3315.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/rfc3315.c b/src/rfc3315.c
index 920907c..4ca43e0 100644
--- a/src/rfc3315.c
+++ b/src/rfc3315.c
@@ -216,6 +216,9 @@ static int dhcp6_maybe_relay(struct state *state, void *inbuff, size_t sz,
   
   for (opt = opts; opt; opt = opt6_next(opt, end))
     {
+      if (opt6_ptr(opt, 0) + opt6_len(opt) >= end) {
+        return 0;
+      }
       int o = new_opt6(opt6_type(opt));
       if (opt6_type(opt) == OPTION6_RELAY_MSG)
 	{
-- 
2.9.5