Mercurial > hg > nginx

comparison src/core/ngx_resolver.c @ 5470:aebdca7e8f8f

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Resolver: fixed response processing. Stricten response header checks: ensure that reserved bits are zeroes, and that the opcode is "standard query". Fixed the "zero-length domain name in DNS response" condition.
author Ruslan Ermilov <ru@nginx.com>
date Fri, 06 Dec 2013 14:30:27 +0400
parents b2fc466a11a7
children 9c96782d9d05
comparison
equal deleted inserted replaced
5469:b2fc466a11a7 5470:aebdca7e8f8f
1020 1020
1021 static void 1021 static void
1022 ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n) 1022 ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n)
1023 { 1023 {
1024 char *err; 1024 char *err;
1025 size_t len;
1026 ngx_uint_t i, times, ident, qident, flags, code, nqs, nan, 1025 ngx_uint_t i, times, ident, qident, flags, code, nqs, nan,
1027 qtype, qclass; 1026 qtype, qclass;
1028 ngx_queue_t *q; 1027 ngx_queue_t *q;
1029 ngx_resolver_qs_t *qs; 1028 ngx_resolver_qs_t *qs;
1030 ngx_resolver_hdr_t *response; 1029 ngx_resolver_hdr_t *response;
1045 "resolver DNS response %ui fl:%04Xui %ui/%ui/%ud/%ud", 1044 "resolver DNS response %ui fl:%04Xui %ui/%ui/%ud/%ud",
1046 ident, flags, nqs, nan, 1045 ident, flags, nqs, nan,
1047 (response->nns_hi << 8) + response->nns_lo, 1046 (response->nns_hi << 8) + response->nns_lo,
1048 (response->nar_hi << 8) + response->nar_lo); 1047 (response->nar_hi << 8) + response->nar_lo);
1049 1048
1050 if (!(flags & 0x8000)) { 1049 /* response to a standard query */
1050 if ((flags & 0xf870) != 0x8000) {
1051 ngx_log_error(r->log_level, r->log, 0, 1051 ngx_log_error(r->log_level, r->log, 0,
1052 "invalid DNS response %ui fl:%04Xui", ident, flags); 1052 "invalid DNS response %ui fl:%04Xui", ident, flags);
1053 return; 1053 return;
1054 } 1054 }
1055 1055
1056 code = flags & 0x7f; 1056 code = flags & 0xf;
1057 1057
1058 if (code == NGX_RESOLVE_FORMERR) { 1058 if (code == NGX_RESOLVE_FORMERR) {
1059 1059
1060 times = 0; 1060 times = 0;
1061 1061
1092 while (i < (ngx_uint_t) n) { 1092 while (i < (ngx_uint_t) n) {
1093 if (buf[i] == '\0') { 1093 if (buf[i] == '\0') {
1094 goto found; 1094 goto found;
1095 } 1095 }
1096 1096
1097 len = buf[i]; 1097 i += 1 + buf[i];
1098 i += 1 + len;
1099 } 1098 }
1100 1099
1101 goto short_response; 1100 goto short_response;
1102 1101
1103 found: 1102 found:
1104 1103
1105 if (i++ == 0) { 1104 if (i++ == sizeof(ngx_resolver_hdr_t)) {
1106 err = "zero-length domain name in DNS response"; 1105 err = "zero-length domain name in DNS response";
1107 goto done; 1106 goto done;
1108 } 1107 }
1109 1108
1110 if (i + sizeof(ngx_resolver_qs_t) + nan * (2 + sizeof(ngx_resolver_an_t)) 1109 if (i + sizeof(ngx_resolver_qs_t) + nan * (2 + sizeof(ngx_resolver_an_t))