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 "bitlbee.h"
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 #ifdef HAVE_RESOLV_A
25 #ifndef HAVE_RESOLV_A_WITH_NS
26 /* Import. */
27 
28 
29 #include <sys/types.h>
30 
31 #include <netinet/in.h>
32 #include <arpa/nameser.h>
33 
34 #include <errno.h>
35 #include <resolv.h>
36 #include <string.h>
37 
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 {
79 	return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
80 }
81 
82 int
ns_skiprr(const u_char * ptr,const u_char * eom,ns_sect section,int count)83 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count)
84 {
85 	const u_char *optr = ptr;
86 
87 	for ((void) NULL; count > 0; count--) {
88 		int b, rdlength;
89 
90 		b = dn_skipname(ptr, eom);
91 		if (b < 0) {
92 			RETERR(EMSGSIZE);
93 		}
94 		ptr += b /*Name*/ + NS_INT16SZ /*Type*/ + NS_INT16SZ /*Class*/;
95 		if (section != ns_s_qd) {
96 			if (ptr + NS_INT32SZ + NS_INT16SZ > eom) {
97 				RETERR(EMSGSIZE);
98 			}
99 			ptr += NS_INT32SZ /*TTL*/;
100 			NS_GET16(rdlength, ptr);
101 			ptr += rdlength /*RData*/;
102 		}
103 	}
104 	if (ptr > eom) {
105 		RETERR(EMSGSIZE);
106 	}
107 	return (ptr - optr);
108 }
109 
110 int
ns_initparse(const u_char * msg,int msglen,ns_msg * handle)111 ns_initparse(const u_char *msg, int msglen, ns_msg *handle)
112 {
113 	const u_char *eom = msg + msglen;
114 	int i;
115 
116 	handle->_msg = msg;
117 	handle->_eom = eom;
118 	if (msg + NS_INT16SZ > eom) {
119 		RETERR(EMSGSIZE);
120 	}
121 	NS_GET16(handle->_id, msg);
122 	if (msg + NS_INT16SZ > eom) {
123 		RETERR(EMSGSIZE);
124 	}
125 	NS_GET16(handle->_flags, msg);
126 	for (i = 0; i < ns_s_max; i++) {
127 		if (msg + NS_INT16SZ > eom) {
128 			RETERR(EMSGSIZE);
129 		}
130 		NS_GET16(handle->_counts[i], msg);
131 	}
132 	for (i = 0; i < ns_s_max; i++) {
133 		if (handle->_counts[i] == 0) {
134 			handle->_sections[i] = NULL;
135 		} else {
136 			int b = ns_skiprr(msg, eom, (ns_sect) i,
137 			                  handle->_counts[i]);
138 
139 			if (b < 0) {
140 				return (-1);
141 			}
142 			handle->_sections[i] = msg;
143 			msg += b;
144 		}
145 	}
146 	if (msg != eom) {
147 		RETERR(EMSGSIZE);
148 	}
149 	setsection(handle, ns_s_max);
150 	return (0);
151 }
152 
153 int
ns_parserr(ns_msg * handle,ns_sect section,int rrnum,ns_rr * rr)154 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr)
155 {
156 	int b;
157 	int tmp;
158 
159 	/* Make section right. */
160 	tmp = section;
161 	if (tmp < 0 || section >= ns_s_max) {
162 		RETERR(ENODEV);
163 	}
164 	if (section != handle->_sect) {
165 		setsection(handle, section);
166 	}
167 
168 	/* Make rrnum right. */
169 	if (rrnum == -1) {
170 		rrnum = handle->_rrnum;
171 	}
172 	if (rrnum < 0 || rrnum >= handle->_counts[(int) section]) {
173 		RETERR(ENODEV);
174 	}
175 	if (rrnum < handle->_rrnum) {
176 		setsection(handle, section);
177 	}
178 	if (rrnum > handle->_rrnum) {
179 		b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
180 		              rrnum - handle->_rrnum);
181 
182 		if (b < 0) {
183 			return (-1);
184 		}
185 		handle->_msg_ptr += b;
186 		handle->_rrnum = rrnum;
187 	}
188 
189 	/* Do the parse. */
190 	b = dn_expand(handle->_msg, handle->_eom,
191 	              handle->_msg_ptr, rr->name, NS_MAXDNAME);
192 	if (b < 0) {
193 		return (-1);
194 	}
195 	handle->_msg_ptr += b;
196 	if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) {
197 		RETERR(EMSGSIZE);
198 	}
199 	NS_GET16(rr->type, handle->_msg_ptr);
200 	NS_GET16(rr->rr_class, handle->_msg_ptr);
201 	if (section == ns_s_qd) {
202 		rr->ttl = 0;
203 		rr->rdlength = 0;
204 		rr->rdata = NULL;
205 	} else {
206 		if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) {
207 			RETERR(EMSGSIZE);
208 		}
209 		NS_GET32(rr->ttl, handle->_msg_ptr);
210 		NS_GET16(rr->rdlength, handle->_msg_ptr);
211 		if (handle->_msg_ptr + rr->rdlength > handle->_eom) {
212 			RETERR(EMSGSIZE);
213 		}
214 		rr->rdata = handle->_msg_ptr;
215 		handle->_msg_ptr += rr->rdlength;
216 	}
217 	if (++handle->_rrnum > handle->_counts[(int) section]) {
218 		setsection(handle, (ns_sect) ((int) section + 1));
219 	}
220 
221 	/* All done. */
222 	return (0);
223 }
224 
225 /* Private. */
226 
227 static void
setsection(ns_msg * msg,ns_sect sect)228 setsection(ns_msg *msg, ns_sect sect)
229 {
230 	msg->_sect = sect;
231 	if (sect == ns_s_max) {
232 		msg->_rrnum = -1;
233 		msg->_msg_ptr = NULL;
234 	} else {
235 		msg->_rrnum = 0;
236 		msg->_msg_ptr = msg->_sections[(int) sect];
237 	}
238 }
239 
240 /*! \file */
241 #endif
242 #endif
243