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 #ifndef lint
19 static const char rcsid[] = "$Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp $";
20 #endif
21
22 /* Import. */
23
24 #include "port_before.h"
25
26 #include <sys/types.h>
27
28 #include <netinet/in.h>
29 #include <arpa/nameser.h>
30
31 #include <errno.h>
32 #include <resolv.h>
33 #include <string.h>
34
35 #include "port_after.h"
36
37 /* Forward. */
38
39 static void setsection(ns_msg *msg, ns_sect sect);
40
41 /* Macros. */
42
43 #if !defined(SOLARIS2) || defined(__COVERITY__)
44 #define RETERR(err) do { errno = (err); return (-1); } while (0)
45 #else
46 #define RETERR(err) \
47 do { errno = (err); if (errno == errno) return (-1); } while (0)
48 #endif
49
50 #define PARSE_FMT_PRESO 0 /* Parse using presentation-format names */
51 #define PARSE_FMT_WIRE 1 /* Parse using network-format names */
52
53 /* Public. */
54
55 /* These need to be in the same order as the nres.h:ns_flag enum. */
56 struct _ns_flagdata _ns_flagdata[16] = {
57 { 0x8000, 15 }, /*%< qr. */
58 { 0x7800, 11 }, /*%< opcode. */
59 { 0x0400, 10 }, /*%< aa. */
60 { 0x0200, 9 }, /*%< tc. */
61 { 0x0100, 8 }, /*%< rd. */
62 { 0x0080, 7 }, /*%< ra. */
63 { 0x0040, 6 }, /*%< z. */
64 { 0x0020, 5 }, /*%< ad. */
65 { 0x0010, 4 }, /*%< cd. */
66 { 0x000f, 0 }, /*%< rcode. */
67 { 0x0000, 0 }, /*%< expansion (1/6). */
68 { 0x0000, 0 }, /*%< expansion (2/6). */
69 { 0x0000, 0 }, /*%< expansion (3/6). */
70 { 0x0000, 0 }, /*%< expansion (4/6). */
71 { 0x0000, 0 }, /*%< expansion (5/6). */
72 { 0x0000, 0 }, /*%< expansion (6/6). */
73 };
74
ns_msg_getflag(ns_msg handle,int flag)75 int ns_msg_getflag(ns_msg handle, int flag) {
76 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
77 }
78
79 int
ns_skiprr(const u_char * ptr,const u_char * eom,ns_sect section,int count)80 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
81 const u_char *optr = ptr;
82
83 for ((void)NULL; count > 0; count--) {
84 int b, rdlength;
85
86 b = dn_skipname(ptr, eom);
87 if (b < 0)
88 RETERR(EMSGSIZE);
89 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
90 if (section != ns_s_qd) {
91 if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
92 RETERR(EMSGSIZE);
93 ptr += NS_INT32SZ/*TTL*/;
94 NS_GET16(rdlength, ptr);
95 ptr += rdlength/*RData*/;
96 }
97 }
98 if (ptr > eom)
99 RETERR(EMSGSIZE);
100 return (ptr - optr);
101 }
102
103 int
ns_initparse(const u_char * msg,int msglen,ns_msg * handle)104 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
105 const u_char *eom = msg + msglen;
106 int i;
107
108 handle->_msg = msg;
109 handle->_eom = eom;
110 if (msg + NS_INT16SZ > eom)
111 RETERR(EMSGSIZE);
112 NS_GET16(handle->_id, msg);
113 if (msg + NS_INT16SZ > eom)
114 RETERR(EMSGSIZE);
115 NS_GET16(handle->_flags, msg);
116 for (i = 0; i < ns_s_max; i++) {
117 if (msg + NS_INT16SZ > eom)
118 RETERR(EMSGSIZE);
119 NS_GET16(handle->_counts[i], msg);
120 }
121 for (i = 0; i < ns_s_max; i++)
122 if (handle->_counts[i] == 0)
123 handle->_sections[i] = NULL;
124 else {
125 int b = ns_skiprr(msg, eom, (ns_sect)i,
126 handle->_counts[i]);
127
128 if (b < 0)
129 return (-1);
130 handle->_sections[i] = msg;
131 msg += b;
132 }
133 if (msg != eom)
134 RETERR(EMSGSIZE);
135 setsection(handle, ns_s_max);
136 return (0);
137 }
138
139 int
ns_parserr(ns_msg * handle,ns_sect section,int rrnum,ns_rr * rr)140 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
141 int b;
142 int tmp;
143
144 /* Make section right. */
145 tmp = section;
146 if (tmp < 0 || section >= ns_s_max)
147 RETERR(ENODEV);
148 if (section != handle->_sect)
149 setsection(handle, section);
150
151 /* Make rrnum right. */
152 if (rrnum == -1)
153 rrnum = handle->_rrnum;
154 if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
155 RETERR(ENODEV);
156 if (rrnum < handle->_rrnum)
157 setsection(handle, section);
158 if (rrnum > handle->_rrnum) {
159 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
160 rrnum - handle->_rrnum);
161
162 if (b < 0)
163 return (-1);
164 handle->_msg_ptr += b;
165 handle->_rrnum = rrnum;
166 }
167
168 /* Do the parse. */
169 b = dn_expand(handle->_msg, handle->_eom,
170 handle->_msg_ptr, rr->name, NS_MAXDNAME);
171 if (b < 0)
172 return (-1);
173 handle->_msg_ptr += b;
174 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
175 RETERR(EMSGSIZE);
176 NS_GET16(rr->type, handle->_msg_ptr);
177 NS_GET16(rr->rr_class, handle->_msg_ptr);
178 if (section == ns_s_qd) {
179 rr->ttl = 0;
180 rr->rdlength = 0;
181 rr->rdata = NULL;
182 } else {
183 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
184 RETERR(EMSGSIZE);
185 NS_GET32(rr->ttl, handle->_msg_ptr);
186 NS_GET16(rr->rdlength, handle->_msg_ptr);
187 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
188 RETERR(EMSGSIZE);
189 rr->rdata = handle->_msg_ptr;
190 handle->_msg_ptr += rr->rdlength;
191 }
192 if (++handle->_rrnum > handle->_counts[(int)section])
193 setsection(handle, (ns_sect)((int)section + 1));
194
195 /* All done. */
196 return (0);
197 }
198
199 /*
200 * This is identical to the above but uses network-format (uncompressed) names.
201 */
202 int
ns_parserr2(ns_msg * handle,ns_sect section,int rrnum,ns_rr2 * rr)203 ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
204 int b;
205 int tmp;
206
207 /* Make section right. */
208 if ((tmp = section) < 0 || section >= ns_s_max)
209 RETERR(ENODEV);
210 if (section != handle->_sect)
211 setsection(handle, section);
212
213 /* Make rrnum right. */
214 if (rrnum == -1)
215 rrnum = handle->_rrnum;
216 if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
217 RETERR(ENODEV);
218 if (rrnum < handle->_rrnum)
219 setsection(handle, section);
220 if (rrnum > handle->_rrnum) {
221 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
222 rrnum - handle->_rrnum);
223
224 if (b < 0)
225 return (-1);
226 handle->_msg_ptr += b;
227 handle->_rrnum = rrnum;
228 }
229
230 /* Do the parse. */
231 b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
232 rr->nname, NS_MAXNNAME, &rr->nnamel);
233 if (b < 0)
234 return (-1);
235 handle->_msg_ptr += b;
236 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
237 RETERR(EMSGSIZE);
238 NS_GET16(rr->type, handle->_msg_ptr);
239 NS_GET16(rr->rr_class, handle->_msg_ptr);
240 if (section == ns_s_qd) {
241 rr->ttl = 0;
242 rr->rdlength = 0;
243 rr->rdata = NULL;
244 } else {
245 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
246 RETERR(EMSGSIZE);
247 NS_GET32(rr->ttl, handle->_msg_ptr);
248 NS_GET16(rr->rdlength, handle->_msg_ptr);
249 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
250 RETERR(EMSGSIZE);
251 rr->rdata = handle->_msg_ptr;
252 handle->_msg_ptr += rr->rdlength;
253 }
254 if (++handle->_rrnum > handle->_counts[(int)section])
255 setsection(handle, (ns_sect)((int)section + 1));
256
257 /* All done. */
258 return (0);
259 }
260
261 /* Private. */
262
263 static void
setsection(ns_msg * msg,ns_sect sect)264 setsection(ns_msg *msg, ns_sect sect) {
265 msg->_sect = sect;
266 if (sect == ns_s_max) {
267 msg->_rrnum = -1;
268 msg->_msg_ptr = NULL;
269 } else {
270 msg->_rrnum = 0;
271 msg->_msg_ptr = msg->_sections[(int)sect];
272 }
273 }
274
275 /*! \file */
276