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From 3d4ff1ba8419546490b464418223132529514033 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] Security fix, CVE-2017-14493, DHCPv6 - Stack buffer
overflow.
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.
CVE: CVE-2017-14493
Upstream-Status: Backport
Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
---
CHANGELOG | 8 ++++++++
src/rfc3315.c | 3 +++
2 files changed, 11 insertions(+)
diff --git a/CHANGELOG b/CHANGELOG
index df6c157..c48378f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -43,6 +43,14 @@ version 2.78
Credit to Felix Wilhelm, Fermin J. Serna, Gabriel Campana
and Kevin Hamacher of the Google Security Team for
finding this.
+
+ 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.
+ CVE-2017-14493 applies.
+ Credit to Felix Wilhelm, Fermin J. Serna, Gabriel Campana
+ and Kevin Hamacher of the Google Security Team for
+ finding this.
version 2.77
diff --git a/src/rfc3315.c b/src/rfc3315.c
index 1687931..920907c 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);
--
1.7.10.4
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