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From f23f4be3cb72d307806e3d3ca14779f69ac5494c Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Mon, 25 Sep 2017 18:52:50 +0100
Subject: [PATCH 3/7] Security fix, CVE-2017-14493, DHCPv6 - Stack buffer
overflow.
commit 3d4ff1ba8419546490b464418223132529514033 upstream
git://thekelleys.org.uk/dnsmasq
Fix stack overflow in DHCPv6 code. An attacker who can send
a DHCPv6 request to dnsmasq can overflow the stack frame and
crash or control dnsmasq.
Upstream-Status: Backport
Signed-off-by: Zhang Xiao <xiao.zhang@windriver.com>
---
src/rfc3315.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/src/rfc3315.c b/src/rfc3315.c
index 73bdee4..8d18a28 100644
--- a/src/rfc3315.c
+++ b/src/rfc3315.c
@@ -206,6 +206,9 @@ static int dhcp6_maybe_relay(struct state *state, void *inbuff, size_t sz,
/* RFC-6939 */
if ((opt = opt6_find(opts, end, OPTION6_CLIENT_MAC, 3)))
{
+ if (opt6_len(opt) - 2 > DHCP_CHADDR_MAX) {
+ return 0;
+ }
state->mac_type = opt6_uint(opt, 0, 2);
state->mac_len = opt6_len(opt) - 2;
memcpy(&state->mac[0], opt6_ptr(opt, 2), state->mac_len);
--
2.11.0
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