1 /*	$NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 christos Exp $	*/
2 
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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  * 	This product includes software developed by the University of
18  * 	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 /*
37  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
38  *
39  * Permission to use, copy, modify, and distribute this software for any
40  * purpose with or without fee is hereby granted, provided that the above
41  * copyright notice and this permission notice appear in all copies, and that
42  * the name of Digital Equipment Corporation not be used in advertising or
43  * publicity pertaining to distribution of the document or software without
44  * specific, written prior permission.
45  *
46  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
47  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
48  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
49  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
50  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
51  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
52  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
53  * SOFTWARE.
54  */
55 
56 /*
57  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
58  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
59  *
60  * Permission to use, copy, modify, and distribute this software for any
61  * purpose with or without fee is hereby granted, provided that the above
62  * copyright notice and this permission notice appear in all copies.
63  *
64  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
65  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
66  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
67  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
68  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
69  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
70  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
71  */
72 #include <sys/cdefs.h>
73 #if defined(LIBC_SCCS) && !defined(lint)
74 #ifdef notdef
75 static const char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
76 static const char rcsid[] = "Id: res_comp.c,v 1.1.2.1.4.1 2004/03/09 08:33:54 marka Exp";
77 #else
78 __RCSID("$NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 christos Exp $");
79 #endif
80 #endif /* LIBC_SCCS and not lint */
81 
82 #include <sys/types.h>
83 #include <sys/param.h>
84 #include <netinet/in.h>
85 #include <arpa/nameser.h>
86 #include <ctype.h>
87 #ifdef ANDROID_CHANGES
88 #include "resolv_private.h"
89 #else
90 #include <resolv.h>
91 #endif
92 #include <stdio.h>
93 #include <string.h>
94 #include <unistd.h>
95 
96 /*
97  * Expand compressed domain name 'src' to full domain name.
98  * 'msg' is a pointer to the begining of the message,
99  * 'eom' points to the first location after the message,
100  * 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
101  * Return size of compressed name or -1 if there was an error.
102  */
103 int
dn_expand(const u_char * msg,const u_char * eom,const u_char * src,char * dst,int dstsiz)104 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
105 	  char *dst, int dstsiz)
106 {
107 	int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
108 
109 	if (n > 0 && dst[0] == '.')
110 		dst[0] = '\0';
111 	return (n);
112 }
113 
114 /*
115  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
116  * Return the size of the compressed name or -1.
117  * 'length' is the size of the array pointed to by 'comp_dn'.
118  */
119 int
dn_comp(const char * src,u_char * dst,int dstsiz,u_char ** dnptrs,u_char ** lastdnptr)120 dn_comp(const char *src, u_char *dst, int dstsiz,
121 	u_char **dnptrs, u_char **lastdnptr)
122 {
123 	return (ns_name_compress(src, dst, (size_t)dstsiz,
124 				 (const u_char **)dnptrs,
125 				 (const u_char **)lastdnptr));
126 }
127 
128 /*
129  * Skip over a compressed domain name. Return the size or -1.
130  */
131 int
dn_skipname(const u_char * ptr,const u_char * eom)132 dn_skipname(const u_char *ptr, const u_char *eom) {
133 	const u_char *saveptr = ptr;
134 
135 	if (ns_name_skip(&ptr, eom) == -1)
136 		return (-1);
137 	return (ptr - saveptr);
138 }
139 
140 /*
141  * Verify that a domain name uses an acceptable character set.
142  */
143 
144 /*
145  * Note the conspicuous absence of ctype macros in these definitions.  On
146  * non-ASCII hosts, we can't depend on string literals or ctype macros to
147  * tell us anything about network-format data.  The rest of the BIND system
148  * is not careful about this, but for some reason, we're doing it right here.
149  */
150 
151 /* BIONIC: We also accept underscores in the middle of labels.
152  *         This extension is needed to make resolution on some VPN networks
153  *         work properly.
154  */
155 
156 #define PERIOD 0x2e
157 #define	hyphenchar(c) ((c) == 0x2d)
158 #define bslashchar(c) ((c) == 0x5c)
159 #define periodchar(c) ((c) == PERIOD)
160 #define asterchar(c) ((c) == 0x2a)
161 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
162 		   || ((c) >= 0x61 && (c) <= 0x7a))
163 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
164 #define underscorechar(c)  ((c) == 0x5f)
165 
166 #define borderchar(c) (alphachar(c) || digitchar(c))
167 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
168 #define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
169 
170 int
res_hnok(const char * dn)171 res_hnok(const char *dn) {
172 	int pch = PERIOD, ch = *dn++;
173 
174 	while (ch != '\0') {
175 		int nch = *dn++;
176 
177 		if (periodchar(ch)) {
178 			;
179 		} else if (periodchar(pch)) {
180 			if (!borderchar(ch))
181 				return (0);
182 		} else if (periodchar(nch) || nch == '\0') {
183 			if (!borderchar(ch))
184 				return (0);
185 		} else {
186 			if (!middlechar(ch))
187 				return (0);
188 		}
189 		pch = ch, ch = nch;
190 	}
191 	return (1);
192 }
193 
194 /*
195  * hostname-like (A, MX, WKS) owners can have "*" as their first label
196  * but must otherwise be as a host name.
197  */
198 int
res_ownok(const char * dn)199 res_ownok(const char *dn) {
200 	if (asterchar(dn[0])) {
201 		if (periodchar(dn[1]))
202 			return (res_hnok(dn+2));
203 		if (dn[1] == '\0')
204 			return (1);
205 	}
206 	return (res_hnok(dn));
207 }
208 
209 /*
210  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
211  * label, but the rest of the name has to look like a host name.
212  */
213 int
res_mailok(const char * dn)214 res_mailok(const char *dn) {
215 	int ch, escaped = 0;
216 
217 	/* "." is a valid missing representation */
218 	if (*dn == '\0')
219 		return (1);
220 
221 	/* otherwise <label>.<hostname> */
222 	while ((ch = *dn++) != '\0') {
223 		if (!domainchar(ch))
224 			return (0);
225 		if (!escaped && periodchar(ch))
226 			break;
227 		if (escaped)
228 			escaped = 0;
229 		else if (bslashchar(ch))
230 			escaped = 1;
231 	}
232 	if (periodchar(ch))
233 		return (res_hnok(dn));
234 	return (0);
235 }
236 
237 /*
238  * This function is quite liberal, since RFC 1034's character sets are only
239  * recommendations.
240  */
241 int
res_dnok(const char * dn)242 res_dnok(const char *dn) {
243 	int ch;
244 
245 	while ((ch = *dn++) != '\0')
246 		if (!domainchar(ch))
247 			return (0);
248 	return (1);
249 }
250 
251 #ifdef BIND_4_COMPAT
252 /*
253  * This module must export the following externally-visible symbols:
254  *	___putlong
255  *	___putshort
256  *	__getlong
257  *	__getshort
258  * Note that one _ comes from C and the others come from us.
259  */
__putlong(u_int32_t src,u_char * dst)260 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
__putshort(u_int16_t src,u_char * dst)261 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
262 #ifndef __ultrix__
_getlong(const u_char * src)263 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
_getshort(const u_char * src)264 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
265 #endif /*__ultrix__*/
266 #endif /*BIND_4_COMPAT*/
267