From 0033eaa7ba2e1a15a8bc2bbe055c6cee264b7147 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 |  8 +++++---

 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/edns0.c b/src/edns0.c

index a9ee717..d3ab895 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 0f8f462..a729c06 100644

--- a/src/forward.c

+++ b/src/forward.c

@@ -1412,6 +1412,10 @@ 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 ec3f283..aa7c664 100644

--- a/src/rfc1035.c

+++ b/src/rfc1035.c

@@ -1185,8 +1185,8 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int

   va_end(ap);	/* clean up variable argument pointer */

   j = p - sav - 2;

- /* this has already been checked against limit before */

- PUTSHORT(j, sav);     /* Now, store real RDLength */

+  /* this has already been checked against limit before */

+  PUTSHORT(j, sav);     /* Now, store real RDLength */

   /* check for overflow of buffer */

   if (limit && ((unsigned char *)limit - p) < 0)

@@ -1246,7 +1246,9 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,

   int nxdomain = 0, auth = 1, trunc = 0, sec_data = 1;

   struct mx_srv_record *rec;

   size_t len;

-  

+  // Make sure we do not underflow here too.

+  if (qlen > (limit - ((char *)header))) return 0;

+

   if (ntohs(header->ancount) != 0 ||

       ntohs(header->nscount) != 0 ||

       ntohs(header->qdcount) == 0 || 

-- 

2.9.5