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| author | Simon Kelley <simon@thekelleys.org.uk> | 2015-04-09 21:48:00 +0100 |
|---|---|---|
| committer | Simon Kelley <simon@thekelleys.org.uk> | 2015-04-09 21:48:00 +0100 |
| commit | ad4a8ff7d9097008d7623df8543df435bfddeac8 (patch) | |
| tree | f52913cad449283488f583b44f500f0ebd3bb0c3 | |
| parent | 04b0ac05377936d121a36873bb63d492cde292c9 (diff) | |
| download | dnsmasq-ad4a8ff7d9097008d7623df8543df435bfddeac8.tar.gz | |
Fix crash on receipt of certain malformed DNS requests.v2.73rc4
| -rw-r--r-- | CHANGELOG | 3 | ||||
| -rw-r--r-- | src/rfc1035.c | 9 |
2 files changed, 9 insertions, 3 deletions
@@ -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 diff --git a/src/rfc1035.c b/src/rfc1035.c index 7a07b0c..a995ab5 100644 --- 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); |