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
73 #include <arpa/nameser.h>
74 #include <ctype.h>
75 #include <netinet/in.h>
76 #include <sys/param.h>
77 #include <sys/types.h>
78 #include <stdio.h>
79 #include <string.h>
80 #include <unistd.h>
81
82 #include "resolv_private.h"
83
84 /*
85 * Expand compressed domain name 'src' to full domain name.
86 * 'msg' is a pointer to the begining of the message,
87 * 'eom' points to the first location after the message,
88 * 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
89 * Return size of compressed name or -1 if there was an error.
90 */
dn_expand(const u_char * msg,const u_char * eom,const u_char * src,char * dst,int dstsiz)91 int dn_expand(const u_char* msg, const u_char* eom, const u_char* src, char* dst, int dstsiz) {
92 int n = ns_name_uncompress(msg, eom, src, dst, (size_t) dstsiz);
93
94 if (n > 0 && dst[0] == '.') dst[0] = '\0';
95 return (n);
96 }
97
98 /*
99 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
100 * Return the size of the compressed name or -1.
101 * 'length' is the size of the array pointed to by 'comp_dn'.
102 */
dn_comp(const char * src,u_char * dst,int dstsiz,u_char ** dnptrs,u_char ** lastdnptr)103 int dn_comp(const char* src, u_char* dst, int dstsiz, u_char** dnptrs, u_char** lastdnptr) {
104 return (ns_name_compress(src, dst, (size_t) dstsiz, (const u_char**) dnptrs,
105 (const u_char**) lastdnptr));
106 }
107
108 /*
109 * Skip over a compressed domain name. Return the size or -1.
110 */
dn_skipname(const u_char * ptr,const u_char * eom)111 int dn_skipname(const u_char* ptr, const u_char* eom) {
112 const u_char* saveptr = ptr;
113
114 if (ns_name_skip(&ptr, eom) == -1) return (-1);
115 return (ptr - saveptr);
116 }
117
118 /*
119 * Verify that a domain name uses an acceptable character set.
120 */
121
122 /*
123 * Note the conspicuous absence of ctype macros in these definitions. On
124 * non-ASCII hosts, we can't depend on string literals or ctype macros to
125 * tell us anything about network-format data. The rest of the BIND system
126 * is not careful about this, but for some reason, we're doing it right here.
127 */
128
129 /* BIONIC: We also accept underscores in the middle of labels.
130 * This extension is needed to make resolution on some VPN networks
131 * work properly.
132 */
133
134 #define PERIOD 0x2e
135 #define hyphenchar(c) ((c) == 0x2d)
136 #define bslashchar(c) ((c) == 0x5c)
137 #define periodchar(c) ((c) == PERIOD)
138 #define asterchar(c) ((c) == 0x2a)
139 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || ((c) >= 0x61 && (c) <= 0x7a))
140 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
141 #define underscorechar(c) ((c) == 0x5f)
142
143 #define borderchar(c) (alphachar(c) || digitchar(c))
144 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
145 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
146
res_hnok(const char * dn)147 int res_hnok(const char* dn) {
148 int pch = PERIOD, ch = *dn++;
149
150 while (ch != '\0') {
151 int nch = *dn++;
152
153 if (periodchar(ch)) {
154 ;
155 } else if (periodchar(pch)) {
156 if (!borderchar(ch)) return (0);
157 } else if (periodchar(nch) || nch == '\0') {
158 if (!borderchar(ch)) return (0);
159 } else {
160 if (!middlechar(ch)) return (0);
161 }
162 pch = ch, ch = nch;
163 }
164 return (1);
165 }
166
167 /*
168 * hostname-like (A, MX, WKS) owners can have "*" as their first label
169 * but must otherwise be as a host name.
170 */
res_ownok(const char * dn)171 int res_ownok(const char* dn) {
172 if (asterchar(dn[0])) {
173 if (periodchar(dn[1])) return (res_hnok(dn + 2));
174 if (dn[1] == '\0') return (1);
175 }
176 return (res_hnok(dn));
177 }
178
179 /*
180 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
181 * label, but the rest of the name has to look like a host name.
182 */
res_mailok(const char * dn)183 int res_mailok(const char* dn) {
184 int ch, escaped = 0;
185
186 /* "." is a valid missing representation */
187 if (*dn == '\0') return (1);
188
189 /* otherwise <label>.<hostname> */
190 while ((ch = *dn++) != '\0') {
191 if (!domainchar(ch)) return (0);
192 if (!escaped && periodchar(ch)) break;
193 if (escaped)
194 escaped = 0;
195 else if (bslashchar(ch))
196 escaped = 1;
197 }
198 if (periodchar(ch)) return (res_hnok(dn));
199 return (0);
200 }
201
202 /*
203 * This function is quite liberal, since RFC 1034's character sets are only
204 * recommendations.
205 */
res_dnok(const char * dn)206 int res_dnok(const char* dn) {
207 int ch;
208
209 while ((ch = *dn++) != '\0')
210 if (!domainchar(ch)) return (0);
211 return (1);
212 }
213