--- /dev/null
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Thu, 9 Apr 2015 21:48:00 +0100
+Subject: [PATCH] Fix crash on receipt of certain malformed DNS requests.
+
+---
+--- a/src/rfc1035.c
++++ b/src/rfc1035.c
+@@ -1198,7 +1198,10 @@ unsigned int extract_request(struct dns_header *header, size_t qlen, char *name,
+ size_t setup_reply(struct dns_header *header, size_t qlen,
+ struct all_addr *addrp, unsigned int flags, unsigned long ttl)
+ {
+- unsigned char *p = skip_questions(header, qlen);
++ unsigned char *p;
++
++ if (!(p = skip_questions(header, qlen)))
++ return 0;
+
+ /* clear authoritative and truncated flags, set QR flag */
+ header->hb3 = (header->hb3 & ~(HB3_AA | HB3_TC)) | HB3_QR;
+@@ -1214,7 +1217,7 @@ size_t setup_reply(struct dns_header *header, size_t qlen,
+ SET_RCODE(header, NOERROR); /* empty domain */
+ else if (flags == F_NXDOMAIN)
+ SET_RCODE(header, NXDOMAIN);
+- else if (p && flags == F_IPV4)
++ else if (flags == F_IPV4)
+ { /* we know the address */
+ SET_RCODE(header, NOERROR);
+ header->ancount = htons(1);
+@@ -1222,7 +1225,7 @@ size_t setup_reply(struct dns_header *header, size_t qlen,
+ add_resource_record(header, NULL, NULL, sizeof(struct dns_header), &p, ttl, NULL, T_A, C_IN, "4", addrp);
+ }
+ #ifdef HAVE_IPV6
+- else if (p && flags == F_IPV6)
++ else if (flags == F_IPV6)
+ {
+ SET_RCODE(header, NOERROR);
+ header->ancount = htons(1);