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_setup.h"
28 #include "ares.h"
29 #include "ares_data.h"
30 #include "ares_private.h"
31
ares__parse_txt_reply(const unsigned char * abuf,size_t alen,ares_bool_t ex,void ** txt_out)32 static int ares__parse_txt_reply(const unsigned char *abuf, size_t alen,
33 ares_bool_t ex, void **txt_out)
34 {
35 ares_status_t status;
36 struct ares_txt_ext *txt_head = NULL;
37 struct ares_txt_ext *txt_last = NULL;
38 struct ares_txt_ext *txt_curr;
39 ares_dns_record_t *dnsrec = NULL;
40 size_t i;
41
42 *txt_out = NULL;
43
44 status = ares_dns_parse(abuf, alen, 0, &dnsrec);
45 if (status != ARES_SUCCESS) {
46 goto done;
47 }
48
49 if (ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_ANSWER) == 0) {
50 status = ARES_ENODATA;
51 goto done;
52 }
53
54 for (i = 0; i < ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_ANSWER); i++) {
55 const ares_dns_rr_t *rr =
56 ares_dns_record_rr_get(dnsrec, ARES_SECTION_ANSWER, i);
57 const unsigned char *ptr;
58 size_t ptr_len;
59
60 if (rr == NULL) {
61 /* Shouldn't be possible */
62 status = ARES_EBADRESP;
63 goto done;
64 }
65
66 /* XXX: Why Chaos? */
67 if ((ares_dns_rr_get_class(rr) != ARES_CLASS_IN &&
68 ares_dns_rr_get_class(rr) != ARES_CLASS_CHAOS) ||
69 ares_dns_rr_get_type(rr) != ARES_REC_TYPE_TXT) {
70 continue;
71 }
72
73 /* Allocate storage for this TXT answer appending it to the list */
74 txt_curr =
75 ares_malloc_data(ex ? ARES_DATATYPE_TXT_EXT : ARES_DATATYPE_TXT_REPLY);
76 if (txt_curr == NULL) {
77 status = ARES_ENOMEM;
78 goto done;
79 }
80
81 /* Link in the record */
82 if (txt_last) {
83 txt_last->next = txt_curr;
84 } else {
85 txt_head = txt_curr;
86 }
87 txt_last = txt_curr;
88
89 /* These days, records are joined, always tag as start */
90 if (ex) {
91 txt_curr->record_start = 1;
92 }
93
94 ptr = ares_dns_rr_get_bin(rr, ARES_RR_TXT_DATA, &ptr_len);
95
96 txt_curr->txt = ares_malloc(ptr_len + 1);
97 if (txt_curr->txt == NULL) {
98 status = ARES_ENOMEM;
99 goto done;
100 }
101 memcpy(txt_curr->txt, ptr, ptr_len);
102 txt_curr->txt[ptr_len] = 0;
103 txt_curr->length = ptr_len;
104 }
105
106 done:
107 /* clean up on error */
108 if (status != ARES_SUCCESS) {
109 if (txt_head) {
110 ares_free_data(txt_head);
111 }
112 } else {
113 /* everything looks fine, return the data */
114 *txt_out = txt_head;
115 }
116 ares_dns_record_destroy(dnsrec);
117 return (int)status;
118 }
119
ares_parse_txt_reply(const unsigned char * abuf,int alen,struct ares_txt_reply ** txt_out)120 int ares_parse_txt_reply(const unsigned char *abuf, int alen,
121 struct ares_txt_reply **txt_out)
122 {
123 if (alen < 0) {
124 return ARES_EBADRESP;
125 }
126 return ares__parse_txt_reply(abuf, (size_t)alen, ARES_FALSE,
127 (void **)txt_out);
128 }
129
ares_parse_txt_reply_ext(const unsigned char * abuf,int alen,struct ares_txt_ext ** txt_out)130 int ares_parse_txt_reply_ext(const unsigned char *abuf, int alen,
131 struct ares_txt_ext **txt_out)
132 {
133 if (alen < 0) {
134 return ARES_EBADRESP;
135 }
136 return ares__parse_txt_reply(abuf, (size_t)alen, ARES_TRUE, (void **)txt_out);
137 }
138