1 /* MIT License
2 *
3 * Copyright (c) 2019 Andrew Selivanov
4 * Copyright (c) 2023 Brad House
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
15 * Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE.
24 *
25 * SPDX-License-Identifier: MIT
26 */
27 #include "ares_private.h"
28
29 #ifdef HAVE_NETINET_IN_H
30 # include <netinet/in.h>
31 #endif
32 #ifdef HAVE_NETDB_H
33 # include <netdb.h>
34 #endif
35 #ifdef HAVE_ARPA_INET_H
36 # include <arpa/inet.h>
37 #endif
38
39 #ifdef HAVE_STRINGS_H
40 # include <strings.h>
41 #endif
42
43 #ifdef HAVE_LIMITS_H
44 # include <limits.h>
45 #endif
46
47
ares_parse_into_addrinfo(const ares_dns_record_t * dnsrec,ares_bool_t cname_only_is_enodata,unsigned short port,struct ares_addrinfo * ai)48 ares_status_t ares_parse_into_addrinfo(const ares_dns_record_t *dnsrec,
49 ares_bool_t cname_only_is_enodata,
50 unsigned short port,
51 struct ares_addrinfo *ai)
52 {
53 ares_status_t status;
54 size_t i;
55 size_t ancount;
56 const char *hostname = NULL;
57 ares_bool_t got_a = ARES_FALSE;
58 ares_bool_t got_aaaa = ARES_FALSE;
59 ares_bool_t got_cname = ARES_FALSE;
60 struct ares_addrinfo_cname *cnames = NULL;
61 struct ares_addrinfo_node *nodes = NULL;
62
63 /* Save question hostname */
64 status = ares_dns_record_query_get(dnsrec, 0, &hostname, NULL, NULL);
65 if (status != ARES_SUCCESS) {
66 goto done; /* LCOV_EXCL_LINE: DefensiveCoding */
67 }
68
69 ancount = ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_ANSWER);
70 if (ancount == 0) {
71 status = ARES_ENODATA;
72 goto done;
73 }
74
75 for (i = 0; i < ancount; i++) {
76 ares_dns_rec_type_t rtype;
77 const ares_dns_rr_t *rr =
78 ares_dns_record_rr_get_const(dnsrec, ARES_SECTION_ANSWER, i);
79
80 if (ares_dns_rr_get_class(rr) != ARES_CLASS_IN) {
81 continue;
82 }
83
84 rtype = ares_dns_rr_get_type(rr);
85
86 /* Issue #683
87 * Old code did this hostname sanity check, however it appears this is
88 * flawed logic. Other resolvers don't do this sanity check. Leaving
89 * this code commented out for future reference.
90 *
91 * rname = ares_dns_rr_get_name(rr);
92 * if ((rtype == ARES_REC_TYPE_A || rtype == ARES_REC_TYPE_AAAA) &&
93 * !ares_strcaseeq(rname, hostname)) {
94 * continue;
95 * }
96 */
97
98 if (rtype == ARES_REC_TYPE_CNAME) {
99 struct ares_addrinfo_cname *cname;
100
101 got_cname = ARES_TRUE;
102 /* replace hostname with data from cname
103 * SA: Seems wrong as it introduces order dependency. */
104 hostname = ares_dns_rr_get_str(rr, ARES_RR_CNAME_CNAME);
105
106 cname = ares_append_addrinfo_cname(&cnames);
107 if (cname == NULL) {
108 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
109 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
110 }
111 cname->ttl = (int)ares_dns_rr_get_ttl(rr);
112 cname->alias = ares_strdup(ares_dns_rr_get_name(rr));
113 if (cname->alias == NULL) {
114 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
115 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
116 }
117 cname->name = ares_strdup(hostname);
118 if (cname->name == NULL) {
119 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
120 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
121 }
122 } else if (rtype == ARES_REC_TYPE_A) {
123 got_a = ARES_TRUE;
124 status =
125 ares_append_ai_node(AF_INET, port, ares_dns_rr_get_ttl(rr),
126 ares_dns_rr_get_addr(rr, ARES_RR_A_ADDR), &nodes);
127 if (status != ARES_SUCCESS) {
128 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
129 }
130 } else if (rtype == ARES_REC_TYPE_AAAA) {
131 got_aaaa = ARES_TRUE;
132 status = ares_append_ai_node(AF_INET6, port, ares_dns_rr_get_ttl(rr),
133 ares_dns_rr_get_addr6(rr, ARES_RR_AAAA_ADDR),
134 &nodes);
135 if (status != ARES_SUCCESS) {
136 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
137 }
138 } else {
139 continue;
140 }
141 }
142
143 if (!got_a && !got_aaaa &&
144 (!got_cname || (got_cname && cname_only_is_enodata))) {
145 status = ARES_ENODATA;
146 goto done;
147 }
148
149 /* save the hostname as ai->name */
150 if (ai->name == NULL || !ares_strcaseeq(ai->name, hostname)) {
151 ares_free(ai->name);
152 ai->name = ares_strdup(hostname);
153 if (ai->name == NULL) {
154 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
155 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
156 }
157 }
158
159 if (got_a || got_aaaa) {
160 ares_addrinfo_cat_nodes(&ai->nodes, nodes);
161 nodes = NULL;
162 }
163
164 if (got_cname) {
165 ares_addrinfo_cat_cnames(&ai->cnames, cnames);
166 cnames = NULL;
167 }
168
169 done:
170 ares_freeaddrinfo_cnames(cnames);
171 ares_freeaddrinfo_nodes(nodes);
172
173 /* compatibility */
174 if (status == ARES_EBADNAME) {
175 status = ARES_EBADRESP;
176 }
177
178 return status;
179 }
180