1 /*-
2 * SPDX-License-Identifier: (BSD-3-Clause AND ISC)
3 *
4 * Copyright (c) 1985, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34 *
35 * Permission to use, copy, modify, and distribute this software for any
36 * purpose with or without fee is hereby granted, provided that the above
37 * copyright notice and this permission notice appear in all copies, and that
38 * the name of Digital Equipment Corporation not be used in advertising or
39 * publicity pertaining to distribution of the document or software without
40 * specific, written prior permission.
41 *
42 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
45 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49 * SOFTWARE.
50 */
51
52 /*
53 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
54 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
55 *
56 * Permission to use, copy, modify, and distribute this software for any
57 * purpose with or without fee is hereby granted, provided that the above
58 * copyright notice and this permission notice appear in all copies.
59 *
60 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
61 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
62 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
63 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
64 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
65 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
66 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
67 */
68
69 #if defined(LIBC_SCCS) && !defined(lint)
70 static const char sccsid[] = "@(#)res_comp.c 8.1 (Berkeley) 6/4/93";
71 static const char rcsid[] = "$Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp $";
72 #endif /* LIBC_SCCS and not lint */
73 #include <sys/cdefs.h>
74 __FBSDID("$FreeBSD$");
75
76 #include "port_before.h"
77 #include <sys/param.h>
78 #include <netinet/in.h>
79 #include <arpa/nameser.h>
80 #include <ctype.h>
81 #include <resolv.h>
82 #include <stdio.h>
83 #include <string.h>
84 #include <unistd.h>
85 #include "port_after.h"
86
87 /*%
88 * Expand compressed domain name 'src' to full domain name.
89 *
90 * \li 'msg' is a pointer to the beginning of the message,
91 * \li 'eom' points to the first location after the message,
92 * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
93 * \li Return size of compressed name or -1 if there was an error.
94 */
95 int
dn_expand(const u_char * msg,const u_char * eom,const u_char * src,char * dst,int dstsiz)96 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
97 char *dst, int dstsiz)
98 {
99 int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
100
101 if (n > 0 && dst[0] == '.')
102 dst[0] = '\0';
103 return (n);
104 }
105
106 /*%
107 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
108 *
109 * \li Return the size of the compressed name or -1.
110 * \li 'length' is the size of the array pointed to by 'comp_dn'.
111 */
112 int
dn_comp(const char * src,u_char * dst,int dstsiz,u_char ** dnptrs,u_char ** lastdnptr)113 dn_comp(const char *src, u_char *dst, int dstsiz,
114 u_char **dnptrs, u_char **lastdnptr)
115 {
116 return (ns_name_compress(src, dst, (size_t)dstsiz,
117 (const u_char **)dnptrs,
118 (const u_char **)lastdnptr));
119 }
120
121 /*%
122 * Skip over a compressed domain name. Return the size or -1.
123 */
124 int
dn_skipname(const u_char * ptr,const u_char * eom)125 dn_skipname(const u_char *ptr, const u_char *eom) {
126 const u_char *saveptr = ptr;
127
128 if (ns_name_skip(&ptr, eom) == -1)
129 return (-1);
130 return (ptr - saveptr);
131 }
132
133 /*%
134 * Verify that a domain name uses an acceptable character set.
135 *
136 * Note the conspicuous absence of ctype macros in these definitions. On
137 * non-ASCII hosts, we can't depend on string literals or ctype macros to
138 * tell us anything about network-format data. The rest of the BIND system
139 * is not careful about this, but for some reason, we're doing it right here.
140 */
141 #define PERIOD 0x2e
142 #define hyphenchar(c) ((c) == 0x2d)
143 #define bslashchar(c) ((c) == 0x5c)
144 #define underscorechar(c) ((c) == 0x5f)
145 #define periodchar(c) ((c) == PERIOD)
146 #define asterchar(c) ((c) == 0x2a)
147 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
148 || ((c) >= 0x61 && (c) <= 0x7a))
149 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
150
151 #ifdef RES_ENFORCE_RFC1034
152 #define borderchar(c) (alphachar(c) || digitchar(c))
153 #else
154 #define borderchar(c) (alphachar(c) || digitchar(c) || underscorechar(c))
155 #endif
156 #define middlechar(c) (borderchar(c) || hyphenchar(c))
157 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
158
159 int
res_hnok(const char * dn)160 res_hnok(const char *dn) {
161 int pch = PERIOD, ch = *dn++;
162
163 while (ch != '\0') {
164 int nch = *dn++;
165
166 if (periodchar(ch)) {
167 (void)NULL;
168 } else if (periodchar(pch)) {
169 if (!borderchar(ch))
170 return (0);
171 } else if (periodchar(nch) || nch == '\0') {
172 if (!borderchar(ch))
173 return (0);
174 } else {
175 if (!middlechar(ch))
176 return (0);
177 }
178 pch = ch, ch = nch;
179 }
180 return (1);
181 }
182
183 /*%
184 * hostname-like (A, MX, WKS) owners can have "*" as their first label
185 * but must otherwise be as a host name.
186 */
187 int
res_ownok(const char * dn)188 res_ownok(const char *dn) {
189 if (asterchar(dn[0])) {
190 if (periodchar(dn[1]))
191 return (res_hnok(dn+2));
192 if (dn[1] == '\0')
193 return (1);
194 }
195 return (res_hnok(dn));
196 }
197
198 /*%
199 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
200 * label, but the rest of the name has to look like a host name.
201 */
202 int
res_mailok(const char * dn)203 res_mailok(const char *dn) {
204 int ch, escaped = 0;
205
206 /* "." is a valid missing representation */
207 if (*dn == '\0')
208 return (1);
209
210 /* otherwise <label>.<hostname> */
211 while ((ch = *dn++) != '\0') {
212 if (!domainchar(ch))
213 return (0);
214 if (!escaped && periodchar(ch))
215 break;
216 if (escaped)
217 escaped = 0;
218 else if (bslashchar(ch))
219 escaped = 1;
220 }
221 if (periodchar(ch))
222 return (res_hnok(dn));
223 return (0);
224 }
225
226 /*%
227 * This function is quite liberal, since RFC1034's character sets are only
228 * recommendations.
229 */
230 int
res_dnok(const char * dn)231 res_dnok(const char *dn) {
232 int ch;
233
234 while ((ch = *dn++) != '\0')
235 if (!domainchar(ch))
236 return (0);
237 return (1);
238 }
239
240 #ifdef BIND_4_COMPAT
241 /*%
242 * This module must export the following externally-visible symbols:
243 * ___putlong
244 * ___putshort
245 * __getlong
246 * __getshort
247 * Note that one _ comes from C and the others come from us.
248 */
249
250 #ifdef SOLARIS2
251 #ifdef __putlong
252 #undef __putlong
253 #endif
254 #ifdef __putshort
255 #undef __putshort
256 #endif
257 #pragma weak putlong = __putlong
258 #pragma weak putshort = __putshort
259 #endif /* SOLARIS2 */
260
__putlong(u_int32_t src,u_char * dst)261 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
__putshort(u_int16_t src,u_char * dst)262 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
263 #ifndef __ultrix__
_getlong(const u_char * src)264 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
_getshort(const u_char * src)265 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
266 #endif /*__ultrix__*/
267 #endif /*BIND_4_COMPAT*/
268
269 /*
270 * Weak aliases for applications that use certain private entry points,
271 * and fail to include <resolv.h>.
272 */
273 #undef dn_comp
274 __weak_reference(__dn_comp, dn_comp);
275 #undef dn_expand
276 __weak_reference(__dn_expand, dn_expand);
277
278 /*! \file */
279