dnsmasq: CVE-2017-14493

Stack Based overflow.

References:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=2017-14493
https://security.googleblog.com/2017/10/behind-masq-yet-more-dns-and-dhcp.html

Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
Signed-off-by: Adrian Dudau <adrian.dudau@enea.com>

2 files changed, 56 insertions, 0 deletions

diff --git a/recipes-networking/dnsmasq/dnsmasq/CVE-2017-14493.patch b/recipes-networking/dnsmasq/dnsmasq/CVE-2017-14493.patch
new file mode 100644
index 0000000..fedb825
--- /dev/null
+++ b/recipes-networking/dnsmasq/dnsmasq/CVE-2017-14493.patch
@@ -0,0 +1,55 @@
+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
+
diff --git a/recipes-networking/dnsmasq/dnsmasq_%.bbappend b/recipes-networking/dnsmasq/dnsmasq_%.bbappend
index 1fc8819..7db502a 100644
--- a/recipes-networking/dnsmasq/dnsmasq_%.bbappend
+++ b/recipes-networking/dnsmasq/dnsmasq_%.bbappend
@@ -4,4 +4,5 @@ FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
 SRC_URI += "file://0001-CVE-2017-14491.patch \
     file://0002-CVE-2017-14491.patch \
     file://CVE-2017-14492.patch \
+    file://CVE-2017-14493.patch \
 "