1 /* $OpenBSD: match.c,v 1.43 2020/11/03 22:53:12 djm Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * Simple pattern matching, with '*' and '?' as wildcards.
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
15 * Copyright (c) 2000 Markus Friedl. All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 #include <sys/types.h>
53 * Returns true if the given string matches the pattern (which may contain ?
54 * and * as wildcards), and zero if it does not match.
57 match_pattern(const char *s, const char *pattern)
60 /* If at end of pattern, accept if also at end of string. */
64 if (*pattern == '*') {
65 /* Skip this and any consecutive asterisks. */
66 while (*pattern == '*')
69 /* If at end of pattern, accept immediately. */
73 /* If next character in pattern is known, optimize. */
74 if (*pattern != '?' && *pattern != '*') {
76 * Look instances of the next character in
77 * pattern, and try to match starting from
82 match_pattern(s + 1, pattern + 1))
88 * Move ahead one character at a time and try to
89 * match at each position.
92 if (match_pattern(s, pattern))
98 * There must be at least one more character in the string.
99 * If we are at the end, fail.
104 /* Check if the next character of the string is acceptable. */
105 if (*pattern != '?' && *pattern != *s)
108 /* Move to the next character, both in string and in pattern. */
116 * Tries to match the string against the
117 * comma-separated sequence of subpatterns (each possibly preceded by ! to
118 * indicate negation). Returns -1 if negation matches, 1 if there is
119 * a positive match, 0 if there is no match at all.
122 match_pattern_list(const char *string, const char *pattern, int dolower)
127 u_int i, subi, len = strlen(pattern);
130 for (i = 0; i < len;) {
131 /* Check if the subpattern is negated. */
132 if (pattern[i] == '!') {
139 * Extract the subpattern up to a comma or end. Convert the
140 * subpattern to lowercase.
143 i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
145 sub[subi] = dolower && isupper((u_char)pattern[i]) ?
146 tolower((u_char)pattern[i]) : pattern[i];
147 /* If subpattern too long, return failure (no match). */
148 if (subi >= sizeof(sub) - 1)
151 /* If the subpattern was terminated by a comma, then skip it. */
152 if (i < len && pattern[i] == ',')
155 /* Null-terminate the subpattern. */
158 /* Try to match the subpattern against the string. */
159 if (match_pattern(string, sub)) {
161 return -1; /* Negative */
163 got_positive = 1; /* Positive */
168 * Return success if got a positive match. If there was a negative
169 * match, we have already returned -1 and never get here.
174 /* Match a list representing users or groups. */
176 match_usergroup_pattern_list(const char *string, const char *pattern)
179 /* Windows usernames may be Unicode and are not case sensitive */
180 return cygwin_ug_match_pattern_list(string, pattern);
182 /* Case sensitive match */
183 return match_pattern_list(string, pattern, 0);
188 * Tries to match the host name (which must be in all lowercase) against the
189 * comma-separated sequence of subpatterns (each possibly preceded by ! to
190 * indicate negation). Returns -1 if negation matches, 1 if there is
191 * a positive match, 0 if there is no match at all.
194 match_hostname(const char *host, const char *pattern)
196 char *hostcopy = xstrdup(host);
200 r = match_pattern_list(hostcopy, pattern, 1);
206 * returns 0 if we get a negative match for the hostname or the ip
207 * or if we get no match at all. returns -1 on error, or 1 on
211 match_host_and_ip(const char *host, const char *ipaddr,
212 const char *patterns)
216 if ((mip = addr_match_list(ipaddr, patterns)) == -2)
217 return -1; /* error in ipaddr match */
218 else if (host == NULL || ipaddr == NULL || mip == -1)
219 return 0; /* negative ip address match, or testing pattern */
221 /* negative hostname match */
222 if ((mhost = match_hostname(host, patterns)) == -1)
224 /* no match at all */
225 if (mhost == 0 && mip == 0)
231 * Match user, user@host_or_ip, user@host_or_ip_list against pattern.
232 * If user, host and ipaddr are all NULL then validate pattern/
233 * Returns -1 on invalid pattern, 0 on no match, 1 on match.
236 match_user(const char *user, const char *host, const char *ipaddr,
243 if (user == NULL && host == NULL && ipaddr == NULL) {
244 if ((p = strchr(pattern, '@')) != NULL &&
245 match_host_and_ip(NULL, NULL, p + 1) < 0)
250 if ((p = strchr(pattern, '@')) == NULL)
251 return match_pattern(user, pattern);
253 pat = xstrdup(pattern);
254 p = strchr(pat, '@');
257 if ((ret = match_pattern(user, pat)) == 1)
258 ret = match_host_and_ip(host, ipaddr, p);
265 * Returns first item from client-list that is also supported by server-list,
266 * caller must free the returned string.
271 match_list(const char *client, const char *server, u_int *next)
273 char *sproposals[MAX_PROP];
274 char *c, *s, *p, *ret, *cp, *sp;
275 int i, j, nproposals;
277 c = cp = xstrdup(client);
278 s = sp = xstrdup(server);
280 for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
281 (p = strsep(&sp, SEP)), i++) {
289 for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
290 (p = strsep(&cp, SEP)), i++) {
291 for (j = 0; j < nproposals; j++) {
292 if (strcmp(p, sproposals[j]) == 0) {
295 *next = (cp == NULL) ?
296 strlen(c) : (u_int)(cp - c);
311 * Filter proposal using pattern-list filter.
312 * "denylist" determines sense of filter:
313 * non-zero indicates that items matching filter should be excluded.
314 * zero indicates that only items matching filter should be included.
315 * returns NULL on allocation error, otherwise caller must free result.
318 filter_list(const char *proposal, const char *filter, int denylist)
320 size_t len = strlen(proposal) + 1;
321 char *fix_prop = malloc(len);
322 char *orig_prop = strdup(proposal);
326 if (fix_prop == NULL || orig_prop == NULL) {
334 while ((cp = strsep(&tmp, ",")) != NULL) {
335 r = match_pattern_list(cp, filter, 0);
336 if ((denylist && r != 1) || (!denylist && r == 1)) {
337 if (*fix_prop != '\0')
338 strlcat(fix_prop, ",", len);
339 strlcat(fix_prop, cp, len);
347 * Filters a comma-separated list of strings, excluding any entry matching
348 * the 'filter' pattern list. Caller must free returned string.
351 match_filter_denylist(const char *proposal, const char *filter)
353 return filter_list(proposal, filter, 1);
357 * Filters a comma-separated list of strings, including only entries matching
358 * the 'filter' pattern list. Caller must free returned string.
361 match_filter_allowlist(const char *proposal, const char *filter)
363 return filter_list(proposal, filter, 0);