Fix crash on receipt of certain malformed DNS requests.

This commit is contained in:
Simon Kelley
2015-04-09 21:48:00 +01:00
parent 04b0ac0537
commit ad4a8ff7d9
2 changed files with 9 additions and 3 deletions

View File

@@ -125,6 +125,9 @@ version 2.72
Fix problem with --local-service option on big-endian platforms
Thanks to Richard Genoud for the patch.
Fix crash on receipt of certain malformed DNS requests. Thanks
to Nick Sampanis for spotting the problem.
version 2.71
Subtle change to error handling to help DNSSEC validation

View File

@@ -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);