dnsmasq: CVE-2017-14495

Lack of free() here.

References:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=2017-14495
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, 70 insertions, 0 deletions

diff --git a/recipes-networking/dnsmasq/dnsmasq/CVE-2017-14495.patch b/recipes-networking/dnsmasq/dnsmasq/CVE-2017-14495.patch
new file mode 100644
index 0000000..ba176a8
--- /dev/null
+++ b/recipes-networking/dnsmasq/dnsmasq/CVE-2017-14495.patch
@@ -0,0 +1,69 @@
+From 51eadb692a5123b9838e5a68ecace3ac579a3a45 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Mon, 25 Sep 2017 20:16:50 +0100
+Subject: [PATCH] Security fix, CVE-2017-14495, OOM in DNS response creation.
+
+Fix out-of-memory Dos vulnerability. An attacker which can
+send malicious DNS queries to dnsmasq can trigger memory
+allocations in the add_pseudoheader function
+The allocated memory is never freed which leads to a DoS
+through memory exhaustion. dnsmasq is vulnerable only
+if one of the following option is specified:
+--add-mac, --add-cpe-id or --add-subnet.
+
+CVE: CVE-2017-14495
+Upstream-Status: Backport
+
+Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
+---
+ CHANGELOG   |   12 ++++++++++++
+ src/edns0.c |    8 +++++++-
+ 2 files changed, 19 insertions(+), 1 deletion(-)
+
+diff --git a/CHANGELOG b/CHANGELOG
+index 8fe00ed..9523329 100644
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -70,6 +70,18 @@ version 2.78
+        Credit to Felix Wilhelm, Fermin J. Serna, Gabriel Campana
+        and Kevin Hamacher of the Google Security Team for
+        finding this.
++
++       Fix out-of-memory Dos vulnerability. An attacker which can
++       send malicious DNS queries to dnsmasq can trigger memory
++       allocations in the add_pseudoheader function
++       The allocated memory is never freed which leads to a DoS
++       through memory exhaustion. dnsmasq is vulnerable only
++       if one of the following option is specified:
++       --add-mac, --add-cpe-id or --add-subnet.
++       CVE-2017-14495 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/edns0.c b/src/edns0.c
+index 95b74ee..89b2692 100644
+--- a/src/edns0.c
++++ b/src/edns0.c
+@@ -192,9 +192,15 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
+          !(p = skip_section(p, 
+                             ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount), 
+                             header, plen)))
++      {
++       free(buff);
+        return plen;
++      }
+       if (p + 11 > limit)
+-       return plen; /* Too big */
++      {
++        free(buff);
++        return plen; /* Too big */
++      }
+       *p++ = 0; /* empty name */
+       PUTSHORT(T_OPT, p);
+       PUTSHORT(udp_sz, p); /* max packet length, 512 if not given in EDNS0 header */
+-- 
+1.7.10.4
+
diff --git a/recipes-networking/dnsmasq/dnsmasq_%.bbappend b/recipes-networking/dnsmasq/dnsmasq_%.bbappend
index 07f8a6c..ee31536 100644
--- a/recipes-networking/dnsmasq/dnsmasq_%.bbappend
+++ b/recipes-networking/dnsmasq/dnsmasq_%.bbappend
@@ -7,4 +7,5 @@ SRC_URI += "file://0001-CVE-2017-14491.patch \
     file://CVE-2017-14493.patch \
     file://CVE-2017-14494.patch \
     file://CVE-2017-14496.patch \
+    file://CVE-2017-14495.patch \
 "