1 /*        $NetBSD: ns_parse.c,v 1.1.1.2 2012/09/09 16:08:05 christos Exp $      */
2 
3 /*
4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5  * Copyright (c) 1996,1999 by Internet Software Consortium.
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #ifndef lint
21 static const char rcsid[] = "Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp ";
22 #endif
23 
24 /* Import. */
25 
26 #include "port_before.h"
27 
28 #include <sys/types.h>
29 
30 #include <netinet/in.h>
31 #include <arpa/nameser.h>
32 
33 #include <errno.h>
34 #include <resolv.h>
35 #include <string.h>
36 
37 #include "port_after.h"
38 
39 /* Forward. */
40 
41 static void         setsection(ns_msg *msg, ns_sect sect);
42 
43 /* Macros. */
44 
45 #if !defined(SOLARIS2) || defined(__COVERITY__)
46 #define RETERR(err) do { errno = (err); return (-1); } while (0)
47 #else
48 #define RETERR(err) \
49           do { errno = (err); if (errno == errno) return (-1); } while (0)
50 #endif
51 
52 #define PARSE_FMT_PRESO 0     /* Parse using presentation-format names */
53 #define PARSE_FMT_WIRE 1      /* Parse using network-format names */
54 
55 /* Public. */
56 
57 /* These need to be in the same order as the nres.h:ns_flag enum. */
58 struct _ns_flagdata _ns_flagdata[16] = {
59           { 0x8000, 15 },               /*%< qr. */
60           { 0x7800, 11 },               /*%< opcode. */
61           { 0x0400, 10 },               /*%< aa. */
62           { 0x0200, 9 },                /*%< tc. */
63           { 0x0100, 8 },                /*%< rd. */
64           { 0x0080, 7 },                /*%< ra. */
65           { 0x0040, 6 },                /*%< z. */
66           { 0x0020, 5 },                /*%< ad. */
67           { 0x0010, 4 },                /*%< cd. */
68           { 0x000f, 0 },                /*%< rcode. */
69           { 0x0000, 0 },                /*%< expansion (1/6). */
70           { 0x0000, 0 },                /*%< expansion (2/6). */
71           { 0x0000, 0 },                /*%< expansion (3/6). */
72           { 0x0000, 0 },                /*%< expansion (4/6). */
73           { 0x0000, 0 },                /*%< expansion (5/6). */
74           { 0x0000, 0 },                /*%< expansion (6/6). */
75 };
76 
ns_msg_getflag(ns_msg handle,int flag)77 int ns_msg_getflag(ns_msg handle, int flag) {
78           return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
79 }
80 
81 int
ns_skiprr(const u_char * ptr,const u_char * eom,ns_sect section,int count)82 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
83           const u_char *optr = ptr;
84 
85           for ((void)NULL; count > 0; count--) {
86                     int b, rdlength;
87 
88                     b = dn_skipname(ptr, eom);
89                     if (b < 0)
90                               RETERR(EMSGSIZE);
91                     ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
92                     if (section != ns_s_qd) {
93                               if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
94                                         RETERR(EMSGSIZE);
95                               ptr += NS_INT32SZ/*TTL*/;
96                               NS_GET16(rdlength, ptr);
97                               ptr += rdlength/*RData*/;
98                     }
99           }
100           if (ptr > eom)
101                     RETERR(EMSGSIZE);
102           return (ptr - optr);
103 }
104 
105 int
ns_initparse(const u_char * msg,int msglen,ns_msg * handle)106 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
107           const u_char *eom = msg + msglen;
108           int i;
109 
110           handle->_msg = msg;
111           handle->_eom = eom;
112           if (msg + NS_INT16SZ > eom)
113                     RETERR(EMSGSIZE);
114           NS_GET16(handle->_id, msg);
115           if (msg + NS_INT16SZ > eom)
116                     RETERR(EMSGSIZE);
117           NS_GET16(handle->_flags, msg);
118           for (i = 0; i < ns_s_max; i++) {
119                     if (msg + NS_INT16SZ > eom)
120                               RETERR(EMSGSIZE);
121                     NS_GET16(handle->_counts[i], msg);
122           }
123           for (i = 0; i < ns_s_max; i++)
124                     if (handle->_counts[i] == 0)
125                               handle->_sections[i] = NULL;
126                     else {
127                               int b = ns_skiprr(msg, eom, (ns_sect)i,
128                                                     handle->_counts[i]);
129 
130                               if (b < 0)
131                                         return (-1);
132                               handle->_sections[i] = msg;
133                               msg += b;
134                     }
135           if (msg != eom)
136                     RETERR(EMSGSIZE);
137           setsection(handle, ns_s_max);
138           return (0);
139 }
140 
141 int
ns_parserr(ns_msg * handle,ns_sect section,int rrnum,ns_rr * rr)142 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
143           int b;
144           int tmp;
145 
146           /* Make section right. */
147           tmp = section;
148           if (tmp < 0 || section >= ns_s_max)
149                     RETERR(ENODEV);
150           if (section != handle->_sect)
151                     setsection(handle, section);
152 
153           /* Make rrnum right. */
154           if (rrnum == -1)
155                     rrnum = handle->_rrnum;
156           if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
157                     RETERR(ENODEV);
158           if (rrnum < handle->_rrnum)
159                     setsection(handle, section);
160           if (rrnum > handle->_rrnum) {
161                     b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
162                                     rrnum - handle->_rrnum);
163 
164                     if (b < 0)
165                               return (-1);
166                     handle->_msg_ptr += b;
167                     handle->_rrnum = rrnum;
168           }
169 
170           /* Do the parse. */
171           b = dn_expand(handle->_msg, handle->_eom,
172                           handle->_msg_ptr, rr->name, NS_MAXDNAME);
173           if (b < 0)
174                     return (-1);
175           handle->_msg_ptr += b;
176           if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
177                     RETERR(EMSGSIZE);
178           NS_GET16(rr->type, handle->_msg_ptr);
179           NS_GET16(rr->rr_class, handle->_msg_ptr);
180           if (section == ns_s_qd) {
181                     rr->ttl = 0;
182                     rr->rdlength = 0;
183                     rr->rdata = NULL;
184           } else {
185                     if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
186                               RETERR(EMSGSIZE);
187                     NS_GET32(rr->ttl, handle->_msg_ptr);
188                     NS_GET16(rr->rdlength, handle->_msg_ptr);
189                     if (handle->_msg_ptr + rr->rdlength > handle->_eom)
190                               RETERR(EMSGSIZE);
191                     rr->rdata = handle->_msg_ptr;
192                     handle->_msg_ptr += rr->rdlength;
193           }
194           if (++handle->_rrnum > handle->_counts[(int)section])
195                     setsection(handle, (ns_sect)((int)section + 1));
196 
197           /* All done. */
198           return (0);
199 }
200 
201 /*
202  * This is identical to the above but uses network-format (uncompressed) names.
203  */
204 int
ns_parserr2(ns_msg * handle,ns_sect section,int rrnum,ns_rr2 * rr)205 ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
206           int b;
207           int tmp;
208 
209           /* Make section right. */
210           if ((tmp = section) < 0 || section >= ns_s_max)
211                     RETERR(ENODEV);
212           if (section != handle->_sect)
213                     setsection(handle, section);
214 
215           /* Make rrnum right. */
216           if (rrnum == -1)
217                     rrnum = handle->_rrnum;
218           if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
219                     RETERR(ENODEV);
220           if (rrnum < handle->_rrnum)
221                     setsection(handle, section);
222           if (rrnum > handle->_rrnum) {
223                     b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
224                                     rrnum - handle->_rrnum);
225 
226                     if (b < 0)
227                               return (-1);
228                     handle->_msg_ptr += b;
229                     handle->_rrnum = rrnum;
230           }
231 
232           /* Do the parse. */
233           b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
234                                   rr->nname, NS_MAXNNAME, &rr->nnamel);
235           if (b < 0)
236                     return (-1);
237           handle->_msg_ptr += b;
238           if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
239                     RETERR(EMSGSIZE);
240           NS_GET16(rr->type, handle->_msg_ptr);
241           NS_GET16(rr->rr_class, handle->_msg_ptr);
242           if (section == ns_s_qd) {
243                     rr->ttl = 0;
244                     rr->rdlength = 0;
245                     rr->rdata = NULL;
246           } else {
247                     if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
248                               RETERR(EMSGSIZE);
249                     NS_GET32(rr->ttl, handle->_msg_ptr);
250                     NS_GET16(rr->rdlength, handle->_msg_ptr);
251                     if (handle->_msg_ptr + rr->rdlength > handle->_eom)
252                               RETERR(EMSGSIZE);
253                     rr->rdata = handle->_msg_ptr;
254                     handle->_msg_ptr += rr->rdlength;
255           }
256           if (++handle->_rrnum > handle->_counts[(int)section])
257                     setsection(handle, (ns_sect)((int)section + 1));
258 
259           /* All done. */
260           return (0);
261 }
262 
263 /* Private. */
264 
265 static void
setsection(ns_msg * msg,ns_sect sect)266 setsection(ns_msg *msg, ns_sect sect) {
267           msg->_sect = sect;
268           if (sect == ns_s_max) {
269                     msg->_rrnum = -1;
270                     msg->_msg_ptr = NULL;
271           } else {
272                     msg->_rrnum = 0;
273                     msg->_msg_ptr = msg->_sections[(int)sect];
274           }
275 }
276 
277 /*! \file */
278