1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 * Copyright (C) 2009 by Jakub Hrozek <jhrozek@redhat.com>
4 *
5 * Permission to use, copy, modify, and distribute this
6 * software and its documentation for any purpose and without
7 * fee is hereby granted, provided that the above copyright
8 * notice appear in all copies and that both that copyright
9 * notice and this permission notice appear in supporting
10 * documentation, and that the name of M.I.T. not be used in
11 * advertising or publicity pertaining to distribution of the
12 * software without specific, written prior permission.
13 * M.I.T. makes no representations about the suitability of
14 * this software for any purpose. It is provided "as is"
15 * without express or implied warranty.
16 */
17
18 #include "ares_setup.h"
19
20 #ifdef HAVE_NETINET_IN_H
21 # include <netinet/in.h>
22 #endif
23 #ifdef HAVE_NETDB_H
24 # include <netdb.h>
25 #endif
26 #ifdef HAVE_ARPA_INET_H
27 # include <arpa/inet.h>
28 #endif
29 #ifdef HAVE_ARPA_NAMESER_H
30 # include <arpa/nameser.h>
31 #else
32 # include "nameser.h"
33 #endif
34 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
35 # include <arpa/nameser_compat.h>
36 #endif
37
38 #include "ares.h"
39 #include "ares_dns.h"
40 #include "ares_data.h"
41 #include "ares_private.h"
42
43 /* AIX portability check */
44 #ifndef T_NAPTR
45 #define T_NAPTR 35 /* naming authority pointer */
46 #endif
47
48 int
ares_parse_naptr_reply(const unsigned char * abuf,int alen,struct ares_naptr_reply ** naptr_out)49 ares_parse_naptr_reply (const unsigned char *abuf, int alen,
50 struct ares_naptr_reply **naptr_out)
51 {
52 unsigned int qdcount, ancount, i;
53 const unsigned char *aptr, *vptr;
54 int status, rr_type, rr_class, rr_len;
55 long len;
56 char *hostname = NULL, *rr_name = NULL;
57 struct ares_naptr_reply *naptr_head = NULL;
58 struct ares_naptr_reply *naptr_last = NULL;
59 struct ares_naptr_reply *naptr_curr;
60
61 /* Set *naptr_out to NULL for all failure cases. */
62 *naptr_out = NULL;
63
64 /* Give up if abuf doesn't have room for a header. */
65 if (alen < HFIXEDSZ)
66 return ARES_EBADRESP;
67
68 /* Fetch the question and answer count from the header. */
69 qdcount = DNS_HEADER_QDCOUNT (abuf);
70 ancount = DNS_HEADER_ANCOUNT (abuf);
71 if (qdcount != 1)
72 return ARES_EBADRESP;
73 if (ancount == 0)
74 return ARES_ENODATA;
75
76 /* Expand the name from the question, and skip past the question. */
77 aptr = abuf + HFIXEDSZ;
78 status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
79 if (status != ARES_SUCCESS)
80 return status;
81
82 if (aptr + len + QFIXEDSZ > abuf + alen)
83 {
84 ares_free (hostname);
85 return ARES_EBADRESP;
86 }
87 aptr += len + QFIXEDSZ;
88
89 /* Examine each answer resource record (RR) in turn. */
90 for (i = 0; i < ancount; i++)
91 {
92 /* Decode the RR up to the data field. */
93 status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
94 if (status != ARES_SUCCESS)
95 {
96 break;
97 }
98 aptr += len;
99 if (aptr + RRFIXEDSZ > abuf + alen)
100 {
101 status = ARES_EBADRESP;
102 break;
103 }
104 rr_type = DNS_RR_TYPE (aptr);
105 rr_class = DNS_RR_CLASS (aptr);
106 rr_len = DNS_RR_LEN (aptr);
107 aptr += RRFIXEDSZ;
108 if (aptr + rr_len > abuf + alen)
109 {
110 status = ARES_EBADRESP;
111 break;
112 }
113
114 /* Check if we are really looking at a NAPTR record */
115 if (rr_class == C_IN && rr_type == T_NAPTR)
116 {
117 /* parse the NAPTR record itself */
118
119 /* RR must contain at least 7 bytes = 2 x int16 + 3 x name */
120 if (rr_len < 7)
121 {
122 status = ARES_EBADRESP;
123 break;
124 }
125
126 /* Allocate storage for this NAPTR answer appending it to the list */
127 naptr_curr = ares_malloc_data(ARES_DATATYPE_NAPTR_REPLY);
128 if (!naptr_curr)
129 {
130 status = ARES_ENOMEM;
131 break;
132 }
133 if (naptr_last)
134 {
135 naptr_last->next = naptr_curr;
136 }
137 else
138 {
139 naptr_head = naptr_curr;
140 }
141 naptr_last = naptr_curr;
142
143 vptr = aptr;
144 naptr_curr->order = DNS__16BIT(vptr);
145 vptr += sizeof(unsigned short);
146 naptr_curr->preference = DNS__16BIT(vptr);
147 vptr += sizeof(unsigned short);
148
149 status = ares_expand_string(vptr, abuf, alen, &naptr_curr->flags, &len);
150 if (status != ARES_SUCCESS)
151 break;
152 vptr += len;
153
154 status = ares_expand_string(vptr, abuf, alen, &naptr_curr->service, &len);
155 if (status != ARES_SUCCESS)
156 break;
157 vptr += len;
158
159 status = ares_expand_string(vptr, abuf, alen, &naptr_curr->regexp, &len);
160 if (status != ARES_SUCCESS)
161 break;
162 vptr += len;
163
164 status = ares_expand_name(vptr, abuf, alen, &naptr_curr->replacement, &len);
165 if (status != ARES_SUCCESS)
166 break;
167 }
168
169 /* Don't lose memory in the next iteration */
170 ares_free (rr_name);
171 rr_name = NULL;
172
173 /* Move on to the next record */
174 aptr += rr_len;
175 }
176
177 if (hostname)
178 ares_free (hostname);
179 if (rr_name)
180 ares_free (rr_name);
181
182 /* clean up on error */
183 if (status != ARES_SUCCESS)
184 {
185 if (naptr_head)
186 ares_free_data (naptr_head);
187 return status;
188 }
189
190 /* everything looks fine, return the data */
191 *naptr_out = naptr_head;
192
193 return ARES_SUCCESS;
194 }
195