1 files changed, 64 insertions, 0 deletions
diff --git a/dnsmasq-2.77-underflow.patch b/dnsmasq-2.77-underflow.patch
new file mode 100644
index 0000000..2a04039
--- /dev/null
+++ b/dnsmasq-2.77-underflow.patch
@@ -0,0 +1,64 @@
+From 684bede049a006a0a47ce88f017ada9f73bf4430 Mon Sep 17 00:00:00 2001
+From: Doran Moppert <dmoppert@redhat.com>
+Date: Tue, 26 Sep 2017 14:48:20 +0930
+Subject: [PATCH] google patch hand-applied
+
+---
+ src/edns0.c   | 10 +++++-----
+ src/forward.c |  4 ++++
+ src/rfc1035.c |  3 +++
+ 3 files changed, 12 insertions(+), 5 deletions(-)
+
+diff --git a/src/edns0.c b/src/edns0.c
+index d75d3cc..7d8cf7f 100644
+--- a/src/edns0.c
++++ b/src/edns0.c
+@@ -212,11 +212,11 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
+       /* Copy back any options */
+       if (buff)
+ 	{
+-          if (p + rdlen > limit)
+-          {
+-            free(buff);
+-            return plen; /* Too big */
+-          }
++	  if (p + rdlen > limit)
++	  {
++	    free(buff);
++	    return plen; /* Too big */
++	  }
+ 	  memcpy(p, buff, rdlen);
+ 	  free(buff);
+ 	  p += rdlen;
+diff --git a/src/forward.c b/src/forward.c
+index ed9c8f6..77059ed 100644
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -1542,6 +1542,10 @@ void receive_query(struct listener *listen, time_t now)
+ 	udp_size = PACKETSZ; /* Sanity check - can't reduce below default. RFC 6891 6.2.3 */
+     }
+ 
++  // Make sure the udp size is not smaller than the incoming message so that we
++  // do not underflow
++  if (udp_size < n) udp_size = n;
++
+ #ifdef HAVE_AUTH
+   if (auth_dns)
+     {
+diff --git a/src/rfc1035.c b/src/rfc1035.c
+index f1edc45..15041cc 100644
+--- a/src/rfc1035.c
++++ b/src/rfc1035.c
+@@ -1326,6 +1326,9 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
+   size_t len;
+   int rd_bit = (header->hb3 & HB3_RD);
+ 
++  // Make sure we do not underflow here too.
++  if (qlen > (limit - ((char *)header))) return 0;
++
+   /* never answer queries with RD unset, to avoid cache snooping. */
+   if (ntohs(header->ancount) != 0 ||
+       ntohs(header->nscount) != 0 ||
+-- 
+2.21.1
+