1 /*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996,1999 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include "port_before.h"
19
20 #include <sys/types.h>
21
22 #include <netinet/in.h>
23 #include <arpa/nameser.h>
24
25 #include <errno.h>
26 #include <resolv.h>
27 #include <string.h>
28
29 #include "port_after.h"
30
31 /* Forward. */
32
33 static void setsection(ns_msg *msg, ns_sect sect);
34
35 /* Macros. */
36
37 #if !defined(SOLARIS2) || defined(__COVERITY__)
38 #define RETERR(err) do { errno = (err); return (-1); } while (0)
39 #else
40 #define RETERR(err) \
41 do { errno = (err); if (errno == errno) return (-1); } while (0)
42 #endif
43
44 #define PARSE_FMT_PRESO 0 /* Parse using presentation-format names */
45 #define PARSE_FMT_WIRE 1 /* Parse using network-format names */
46
47 /* Public. */
48
49 /* These need to be in the same order as the nres.h:ns_flag enum. */
50 struct _ns_flagdata _ns_flagdata[16] = {
51 { 0x8000, 15 }, /*%< qr. */
52 { 0x7800, 11 }, /*%< opcode. */
53 { 0x0400, 10 }, /*%< aa. */
54 { 0x0200, 9 }, /*%< tc. */
55 { 0x0100, 8 }, /*%< rd. */
56 { 0x0080, 7 }, /*%< ra. */
57 { 0x0040, 6 }, /*%< z. */
58 { 0x0020, 5 }, /*%< ad. */
59 { 0x0010, 4 }, /*%< cd. */
60 { 0x000f, 0 }, /*%< rcode. */
61 { 0x0000, 0 }, /*%< expansion (1/6). */
62 { 0x0000, 0 }, /*%< expansion (2/6). */
63 { 0x0000, 0 }, /*%< expansion (3/6). */
64 { 0x0000, 0 }, /*%< expansion (4/6). */
65 { 0x0000, 0 }, /*%< expansion (5/6). */
66 { 0x0000, 0 }, /*%< expansion (6/6). */
67 };
68
ns_msg_getflag(ns_msg handle,int flag)69 int ns_msg_getflag(ns_msg handle, int flag) {
70 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
71 }
72
73 int
ns_skiprr(const u_char * ptr,const u_char * eom,ns_sect section,int count)74 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
75 const u_char *optr = ptr;
76
77 for ((void)NULL; count > 0; count--) {
78 int b, rdlength;
79
80 b = dn_skipname(ptr, eom);
81 if (b < 0)
82 RETERR(EMSGSIZE);
83 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
84 if (section != ns_s_qd) {
85 if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
86 RETERR(EMSGSIZE);
87 ptr += NS_INT32SZ/*TTL*/;
88 NS_GET16(rdlength, ptr);
89 ptr += rdlength/*RData*/;
90 }
91 }
92 if (ptr > eom)
93 RETERR(EMSGSIZE);
94 return (ptr - optr);
95 }
96
97 int
ns_initparse(const u_char * msg,int msglen,ns_msg * handle)98 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
99 const u_char *eom = msg + msglen;
100 int i;
101
102 handle->_msg = msg;
103 handle->_eom = eom;
104 if (msg + NS_INT16SZ > eom)
105 RETERR(EMSGSIZE);
106 NS_GET16(handle->_id, msg);
107 if (msg + NS_INT16SZ > eom)
108 RETERR(EMSGSIZE);
109 NS_GET16(handle->_flags, msg);
110 for (i = 0; i < ns_s_max; i++) {
111 if (msg + NS_INT16SZ > eom)
112 RETERR(EMSGSIZE);
113 NS_GET16(handle->_counts[i], msg);
114 }
115 for (i = 0; i < ns_s_max; i++)
116 if (handle->_counts[i] == 0)
117 handle->_sections[i] = NULL;
118 else {
119 int b = ns_skiprr(msg, eom, (ns_sect)i,
120 handle->_counts[i]);
121
122 if (b < 0)
123 return (-1);
124 handle->_sections[i] = msg;
125 msg += b;
126 }
127 if (msg != eom)
128 RETERR(EMSGSIZE);
129 setsection(handle, ns_s_max);
130 return (0);
131 }
132
133 int
ns_parserr(ns_msg * handle,ns_sect section,int rrnum,ns_rr * rr)134 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
135 int b;
136 int tmp;
137
138 /* Make section right. */
139 tmp = section;
140 if (tmp < 0 || section >= ns_s_max)
141 RETERR(ENODEV);
142 if (section != handle->_sect)
143 setsection(handle, section);
144
145 /* Make rrnum right. */
146 if (rrnum == -1)
147 rrnum = handle->_rrnum;
148 if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
149 RETERR(ENODEV);
150 if (rrnum < handle->_rrnum)
151 setsection(handle, section);
152 if (rrnum > handle->_rrnum) {
153 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
154 rrnum - handle->_rrnum);
155
156 if (b < 0)
157 return (-1);
158 handle->_msg_ptr += b;
159 handle->_rrnum = rrnum;
160 }
161
162 /* Do the parse. */
163 b = dn_expand(handle->_msg, handle->_eom,
164 handle->_msg_ptr, rr->name, NS_MAXDNAME);
165 if (b < 0)
166 return (-1);
167 handle->_msg_ptr += b;
168 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
169 RETERR(EMSGSIZE);
170 NS_GET16(rr->type, handle->_msg_ptr);
171 NS_GET16(rr->rr_class, handle->_msg_ptr);
172 if (section == ns_s_qd) {
173 rr->ttl = 0;
174 rr->rdlength = 0;
175 rr->rdata = NULL;
176 } else {
177 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
178 RETERR(EMSGSIZE);
179 NS_GET32(rr->ttl, handle->_msg_ptr);
180 NS_GET16(rr->rdlength, handle->_msg_ptr);
181 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
182 RETERR(EMSGSIZE);
183 rr->rdata = handle->_msg_ptr;
184 handle->_msg_ptr += rr->rdlength;
185 }
186 if (++handle->_rrnum > handle->_counts[(int)section])
187 setsection(handle, (ns_sect)((int)section + 1));
188
189 /* All done. */
190 return (0);
191 }
192
193 /*
194 * This is identical to the above but uses network-format (uncompressed) names.
195 */
196 int
ns_parserr2(ns_msg * handle,ns_sect section,int rrnum,ns_rr2 * rr)197 ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
198 int b;
199 int tmp;
200
201 /* Make section right. */
202 if ((tmp = section) < 0 || section >= ns_s_max)
203 RETERR(ENODEV);
204 if (section != handle->_sect)
205 setsection(handle, section);
206
207 /* Make rrnum right. */
208 if (rrnum == -1)
209 rrnum = handle->_rrnum;
210 if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
211 RETERR(ENODEV);
212 if (rrnum < handle->_rrnum)
213 setsection(handle, section);
214 if (rrnum > handle->_rrnum) {
215 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
216 rrnum - handle->_rrnum);
217
218 if (b < 0)
219 return (-1);
220 handle->_msg_ptr += b;
221 handle->_rrnum = rrnum;
222 }
223
224 /* Do the parse. */
225 b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
226 rr->nname, NS_MAXNNAME, &rr->nnamel);
227 if (b < 0)
228 return (-1);
229 handle->_msg_ptr += b;
230 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
231 RETERR(EMSGSIZE);
232 NS_GET16(rr->type, handle->_msg_ptr);
233 NS_GET16(rr->rr_class, handle->_msg_ptr);
234 if (section == ns_s_qd) {
235 rr->ttl = 0;
236 rr->rdlength = 0;
237 rr->rdata = NULL;
238 } else {
239 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
240 RETERR(EMSGSIZE);
241 NS_GET32(rr->ttl, handle->_msg_ptr);
242 NS_GET16(rr->rdlength, handle->_msg_ptr);
243 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
244 RETERR(EMSGSIZE);
245 rr->rdata = handle->_msg_ptr;
246 handle->_msg_ptr += rr->rdlength;
247 }
248 if (++handle->_rrnum > handle->_counts[(int)section])
249 setsection(handle, (ns_sect)((int)section + 1));
250
251 /* All done. */
252 return (0);
253 }
254
255 /* Private. */
256
257 static void
setsection(ns_msg * msg,ns_sect sect)258 setsection(ns_msg *msg, ns_sect sect) {
259 msg->_sect = sect;
260 if (sect == ns_s_max) {
261 msg->_rrnum = -1;
262 msg->_msg_ptr = NULL;
263 } else {
264 msg->_rrnum = 0;
265 msg->_msg_ptr = msg->_sections[(int)sect];
266 }
267 }
268
269 /*! \file */
270