1 /* MIT License
2 *
3 * Copyright (c) 2023 Brad House
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a copy
6 * of this software and associated documentation files (the "Software"), to deal
7 * in the Software without restriction, including without limitation the rights
8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 * copies of the Software, and to permit persons to whom the Software is
10 * furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 *
24 * SPDX-License-Identifier: MIT
25 */
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
ares_parse_ns_reply(const unsigned char * abuf,int alen_int,struct hostent ** host)39 int ares_parse_ns_reply(const unsigned char *abuf, int alen_int,
40 struct hostent **host)
41 {
42 ares_status_t status;
43 size_t alen;
44 size_t nscount = 0;
45 struct hostent *hostent = NULL;
46 const char *hostname = NULL;
47 ares_dns_record_t *dnsrec = NULL;
48 size_t i;
49 size_t ancount;
50
51 *host = NULL;
52
53 if (alen_int < 0) {
54 return ARES_EBADRESP;
55 }
56
57 alen = (size_t)alen_int;
58
59 status = ares_dns_parse(abuf, alen, 0, &dnsrec);
60 if (status != ARES_SUCCESS) {
61 goto done;
62 }
63
64 ancount = ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_ANSWER);
65 if (ancount == 0) {
66 status = ARES_ENODATA;
67 goto done;
68 }
69
70 /* Response structure */
71 hostent = ares_malloc(sizeof(*hostent));
72 if (hostent == NULL) {
73 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
74 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
75 }
76
77 memset(hostent, 0, sizeof(*hostent));
78
79 hostent->h_addr_list = ares_malloc(sizeof(*hostent->h_addr_list));
80 if (hostent->h_addr_list == NULL) {
81 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
82 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
83 }
84 hostent->h_addr_list[0] = NULL;
85 hostent->h_addrtype = AF_INET;
86 hostent->h_length = sizeof(struct in_addr);
87
88 /* Fill in hostname */
89 status = ares_dns_record_query_get(dnsrec, 0, &hostname, NULL, NULL);
90 if (status != ARES_SUCCESS) {
91 goto done; /* LCOV_EXCL_LINE: DefensiveCoding */
92 }
93 hostent->h_name = ares_strdup(hostname);
94 if (hostent->h_name == NULL) {
95 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
96 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
97 }
98
99 /* Preallocate the maximum number + 1 */
100 hostent->h_aliases = ares_malloc((ancount + 1) * sizeof(*hostent->h_aliases));
101 if (hostent->h_aliases == NULL) {
102 status = ARES_ENOMEM; /* LCOV_EXCL_LINE: OutOfMemory */
103 goto done; /* LCOV_EXCL_LINE: OutOfMemory */
104 }
105 memset(hostent->h_aliases, 0, (ancount + 1) * sizeof(*hostent->h_aliases));
106
107 for (i = 0; i < ancount; i++) {
108 const ares_dns_rr_t *rr =
109 ares_dns_record_rr_get(dnsrec, ARES_SECTION_ANSWER, i);
110
111 if (rr == NULL) {
112 /* Shouldn't be possible */
113 status = ARES_EBADRESP; /* LCOV_EXCL_LINE: DefensiveCoding */
114 goto done; /* LCOV_EXCL_LINE: DefensiveCoding */
115 }
116
117 if (ares_dns_rr_get_class(rr) != ARES_CLASS_IN ||
118 ares_dns_rr_get_type(rr) != ARES_REC_TYPE_NS) {
119 continue;
120 }
121
122 hostname = ares_dns_rr_get_str(rr, ARES_RR_NS_NSDNAME);
123 if (hostname == NULL) {
124 status = ARES_EBADRESP; /* LCOV_EXCL_LINE: DefensiveCoding */
125 goto done; /* LCOV_EXCL_LINE: DefensiveCoding */
126 }
127
128 hostent->h_aliases[nscount] = ares_strdup(hostname);
129 if (hostent->h_aliases[nscount] == NULL) {
130 status = ARES_ENOMEM;
131 goto done;
132 }
133 nscount++;
134 }
135
136 if (nscount == 0) {
137 status = ARES_ENODATA;
138 } else {
139 status = ARES_SUCCESS;
140 }
141
142 done:
143 if (status != ARES_SUCCESS) {
144 ares_free_hostent(hostent);
145 /* Compatibility */
146 if (status == ARES_EBADNAME) {
147 status = ARES_EBADRESP;
148 }
149 } else {
150 *host = hostent;
151 }
152 ares_dns_record_destroy(dnsrec);
153 return (int)status;
154 }
155