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djm@openbsd.org312d2f22018-07-04 13:49:31 +00001/* $OpenBSD: match.c,v 1.38 2018/07/04 13:49:31 djm Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11004 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11006 * Simple pattern matching, with '*' and '?' as wildcards.
Damien Miller4af51302000-04-16 11:18:38 +10007 *
Damien Millere4340be2000-09-16 13:29:08 +11008 * 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".
Damien Miller95def091999-11-25 00:26:21 +110013 */
Ben Lindstromb9be60a2001-03-11 01:49:19 +000014/*
15 * Copyright (c) 2000 Markus Friedl. All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
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.
25 *
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.
36 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100037
38#include "includes.h"
Damien Millerc7b06362006-03-15 11:53:45 +110039
Damien Millerd7834352006-08-05 12:39:39 +100040#include <sys/types.h>
41
Damien Millerc7b06362006-03-15 11:53:45 +110042#include <ctype.h>
Darren Tuckera627d422013-06-02 07:31:17 +100043#include <stdlib.h>
Damien Millere3476ed2006-07-24 14:13:33 +100044#include <string.h>
djm@openbsd.orgdd3e2292017-03-10 04:24:55 +000045#include <stdio.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100046
Ben Lindstromb9be60a2001-03-11 01:49:19 +000047#include "xmalloc.h"
Damien Millerd7834352006-08-05 12:39:39 +100048#include "match.h"
djm@openbsd.orgdd3e2292017-03-10 04:24:55 +000049#include "misc.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100050
Damien Miller5428f641999-11-25 11:54:57 +110051/*
52 * Returns true if the given string matches the pattern (which may contain ?
53 * and * as wildcards), and zero if it does not match.
54 */
Damien Miller95def091999-11-25 00:26:21 +110055
Damien Miller4af51302000-04-16 11:18:38 +100056int
Damien Miller95def091999-11-25 00:26:21 +110057match_pattern(const char *s, const char *pattern)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100058{
Damien Miller95def091999-11-25 00:26:21 +110059 for (;;) {
60 /* If at end of pattern, accept if also at end of string. */
61 if (!*pattern)
62 return !*s;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100063
Damien Miller95def091999-11-25 00:26:21 +110064 if (*pattern == '*') {
65 /* Skip the asterisk. */
66 pattern++;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100067
Damien Miller95def091999-11-25 00:26:21 +110068 /* If at end of pattern, accept immediately. */
69 if (!*pattern)
70 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100071
Damien Miller95def091999-11-25 00:26:21 +110072 /* If next character in pattern is known, optimize. */
73 if (*pattern != '?' && *pattern != '*') {
Damien Miller5428f641999-11-25 11:54:57 +110074 /*
75 * Look instances of the next character in
76 * pattern, and try to match starting from
77 * those.
78 */
Damien Miller95def091999-11-25 00:26:21 +110079 for (; *s; s++)
80 if (*s == *pattern &&
81 match_pattern(s + 1, pattern + 1))
82 return 1;
83 /* Failed. */
84 return 0;
85 }
Damien Miller5428f641999-11-25 11:54:57 +110086 /*
87 * Move ahead one character at a time and try to
88 * match at each position.
89 */
Damien Miller95def091999-11-25 00:26:21 +110090 for (; *s; s++)
91 if (match_pattern(s, pattern))
92 return 1;
93 /* Failed. */
94 return 0;
95 }
Damien Miller5428f641999-11-25 11:54:57 +110096 /*
97 * There must be at least one more character in the string.
98 * If we are at the end, fail.
99 */
Damien Miller95def091999-11-25 00:26:21 +1100100 if (!*s)
101 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000102
Damien Miller5428f641999-11-25 11:54:57 +1100103 /* Check if the next character of the string is acceptable. */
Damien Miller95def091999-11-25 00:26:21 +1100104 if (*pattern != '?' && *pattern != *s)
105 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000106
Damien Miller5428f641999-11-25 11:54:57 +1100107 /* Move to the next character, both in string and in pattern. */
Damien Miller95def091999-11-25 00:26:21 +1100108 s++;
109 pattern++;
110 }
111 /* NOTREACHED */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000112}
Damien Miller450a7a12000-03-26 13:04:51 +1000113
114/*
Ben Lindstrom9eab2622001-12-06 18:06:05 +0000115 * Tries to match the string against the
Damien Miller450a7a12000-03-26 13:04:51 +1000116 * comma-separated sequence of subpatterns (each possibly preceded by ! to
Damien Millerd3a18572000-06-07 19:55:44 +1000117 * indicate negation). Returns -1 if negation matches, 1 if there is
118 * a positive match, 0 if there is no match at all.
Damien Miller450a7a12000-03-26 13:04:51 +1000119 */
Damien Miller450a7a12000-03-26 13:04:51 +1000120int
djm@openbsd.orge661a862015-05-04 06:10:48 +0000121match_pattern_list(const char *string, const char *pattern, int dolower)
Damien Miller450a7a12000-03-26 13:04:51 +1000122{
123 char sub[1024];
124 int negated;
125 int got_positive;
djm@openbsd.orge661a862015-05-04 06:10:48 +0000126 u_int i, subi, len = strlen(pattern);
Damien Miller450a7a12000-03-26 13:04:51 +1000127
128 got_positive = 0;
129 for (i = 0; i < len;) {
130 /* Check if the subpattern is negated. */
131 if (pattern[i] == '!') {
132 negated = 1;
133 i++;
134 } else
135 negated = 0;
136
137 /*
138 * Extract the subpattern up to a comma or end. Convert the
139 * subpattern to lowercase.
140 */
141 for (subi = 0;
Damien Miller9f0f5c62001-12-21 14:45:46 +1100142 i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
143 subi++, i++)
Damien Millerfdb23062013-11-21 13:57:15 +1100144 sub[subi] = dolower && isupper((u_char)pattern[i]) ?
145 tolower((u_char)pattern[i]) : pattern[i];
Damien Miller450a7a12000-03-26 13:04:51 +1000146 /* If subpattern too long, return failure (no match). */
147 if (subi >= sizeof(sub) - 1)
148 return 0;
149
djm@openbsd.orgec2892b2017-03-10 03:52:48 +0000150 /* If the subpattern was terminated by a comma, then skip it. */
Damien Miller450a7a12000-03-26 13:04:51 +1000151 if (i < len && pattern[i] == ',')
152 i++;
153
154 /* Null-terminate the subpattern. */
155 sub[subi] = '\0';
156
Ben Lindstrom9eab2622001-12-06 18:06:05 +0000157 /* Try to match the subpattern against the string. */
158 if (match_pattern(string, sub)) {
Damien Miller450a7a12000-03-26 13:04:51 +1000159 if (negated)
Damien Millerd3a18572000-06-07 19:55:44 +1000160 return -1; /* Negative */
Damien Miller450a7a12000-03-26 13:04:51 +1000161 else
Damien Millerd3a18572000-06-07 19:55:44 +1000162 got_positive = 1; /* Positive */
djm@openbsd.orga5ad3a92016-09-21 16:55:42 +0000163 }
Damien Miller450a7a12000-03-26 13:04:51 +1000164 }
165
166 /*
167 * Return success if got a positive match. If there was a negative
Damien Millerd3a18572000-06-07 19:55:44 +1000168 * match, we have already returned -1 and never get here.
Damien Miller450a7a12000-03-26 13:04:51 +1000169 */
170 return got_positive;
171}
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000172
Ben Lindstromf0c50292001-06-25 05:17:53 +0000173/*
Ben Lindstrom9eab2622001-12-06 18:06:05 +0000174 * Tries to match the host name (which must be in all lowercase) against the
175 * comma-separated sequence of subpatterns (each possibly preceded by ! to
176 * indicate negation). Returns -1 if negation matches, 1 if there is
177 * a positive match, 0 if there is no match at all.
178 */
179int
djm@openbsd.orge661a862015-05-04 06:10:48 +0000180match_hostname(const char *host, const char *pattern)
Ben Lindstrom9eab2622001-12-06 18:06:05 +0000181{
djm@openbsd.orgdd3e2292017-03-10 04:24:55 +0000182 char *hostcopy = xstrdup(host);
183 int r;
184
185 lowercase(hostcopy);
186 r = match_pattern_list(hostcopy, pattern, 1);
187 free(hostcopy);
188 return r;
Ben Lindstrom9eab2622001-12-06 18:06:05 +0000189}
190
191/*
Ben Lindstromf0c50292001-06-25 05:17:53 +0000192 * returns 0 if we get a negative match for the hostname or the ip
Darren Tucker896ad5a2008-06-11 09:34:46 +1000193 * or if we get no match at all. returns -1 on error, or 1 on
194 * successful match.
Ben Lindstromf0c50292001-06-25 05:17:53 +0000195 */
196int
197match_host_and_ip(const char *host, const char *ipaddr,
198 const char *patterns)
199{
200 int mhost, mip;
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000201
Darren Tucker896ad5a2008-06-11 09:34:46 +1000202 if ((mip = addr_match_list(ipaddr, patterns)) == -2)
djm@openbsd.org010359b2016-11-06 05:46:37 +0000203 return -1; /* error in ipaddr match */
204 else if (host == NULL || ipaddr == NULL || mip == -1)
205 return 0; /* negative ip address match, or testing pattern */
Darren Tucker896ad5a2008-06-11 09:34:46 +1000206
Ben Lindstromf0c50292001-06-25 05:17:53 +0000207 /* negative hostname match */
djm@openbsd.orge661a862015-05-04 06:10:48 +0000208 if ((mhost = match_hostname(host, patterns)) == -1)
Ben Lindstromf0c50292001-06-25 05:17:53 +0000209 return 0;
210 /* no match at all */
211 if (mhost == 0 && mip == 0)
212 return 0;
213 return 1;
214}
215
216/*
djm@openbsd.org010359b2016-11-06 05:46:37 +0000217 * Match user, user@host_or_ip, user@host_or_ip_list against pattern.
218 * If user, host and ipaddr are all NULL then validate pattern/
219 * Returns -1 on invalid pattern, 0 on no match, 1 on match.
Ben Lindstrom60260022001-07-04 04:56:44 +0000220 */
221int
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000222match_user(const char *user, const char *host, const char *ipaddr,
Ben Lindstrom60260022001-07-04 04:56:44 +0000223 const char *pattern)
224{
225 char *p, *pat;
226 int ret;
227
djm@openbsd.org010359b2016-11-06 05:46:37 +0000228 /* test mode */
229 if (user == NULL && host == NULL && ipaddr == NULL) {
230 if ((p = strchr(pattern, '@')) != NULL &&
231 match_host_and_ip(NULL, NULL, p + 1) < 0)
232 return -1;
233 return 0;
234 }
235
Ben Lindstrom60260022001-07-04 04:56:44 +0000236 if ((p = strchr(pattern,'@')) == NULL)
237 return match_pattern(user, pattern);
238
239 pat = xstrdup(pattern);
240 p = strchr(pat, '@');
241 *p++ = '\0';
242
243 if ((ret = match_pattern(user, pat)) == 1)
Ben Lindstrom3fb5d002002-03-05 01:42:42 +0000244 ret = match_host_and_ip(host, ipaddr, p);
Darren Tuckera627d422013-06-02 07:31:17 +1000245 free(pat);
Ben Lindstrom60260022001-07-04 04:56:44 +0000246
247 return ret;
248}
249
250/*
Ben Lindstromf0c50292001-06-25 05:17:53 +0000251 * Returns first item from client-list that is also supported by server-list,
Darren Tuckera627d422013-06-02 07:31:17 +1000252 * caller must free the returned string.
Ben Lindstromf0c50292001-06-25 05:17:53 +0000253 */
Damien Millerafc7a5d2002-02-13 13:55:30 +1100254#define MAX_PROP 40
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000255#define SEP ","
256char *
257match_list(const char *client, const char *server, u_int *next)
258{
259 char *sproposals[MAX_PROP];
260 char *c, *s, *p, *ret, *cp, *sp;
261 int i, j, nproposals;
262
263 c = cp = xstrdup(client);
264 s = sp = xstrdup(server);
265
266 for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
Damien Miller9f0f5c62001-12-21 14:45:46 +1100267 (p = strsep(&sp, SEP)), i++) {
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000268 if (i < MAX_PROP)
269 sproposals[i] = p;
270 else
271 break;
272 }
273 nproposals = i;
274
275 for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
Damien Miller9f0f5c62001-12-21 14:45:46 +1100276 (p = strsep(&cp, SEP)), i++) {
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000277 for (j = 0; j < nproposals; j++) {
278 if (strcmp(p, sproposals[j]) == 0) {
279 ret = xstrdup(p);
280 if (next != NULL)
281 *next = (cp == NULL) ?
Damien Millereccb9de2005-06-17 12:59:34 +1000282 strlen(c) : (u_int)(cp - c);
Darren Tuckera627d422013-06-02 07:31:17 +1000283 free(c);
284 free(s);
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000285 return ret;
286 }
287 }
288 }
289 if (next != NULL)
290 *next = strlen(c);
Darren Tuckera627d422013-06-02 07:31:17 +1000291 free(c);
292 free(s);
Ben Lindstromb9be60a2001-03-11 01:49:19 +0000293 return NULL;
294}
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000295
296/*
djm@openbsd.org312d2f22018-07-04 13:49:31 +0000297 * Filter proposal using pattern-list filter.
298 * "blacklist" determines sense of filter:
299 * non-zero indicates that items matching filter should be excluded.
300 * zero indicates that only items matching filter should be included.
301 * returns NULL on allocation error, otherwise caller must free result.
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000302 */
djm@openbsd.org312d2f22018-07-04 13:49:31 +0000303static char *
304filter_list(const char *proposal, const char *filter, int blacklist)
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000305{
306 size_t len = strlen(proposal) + 1;
307 char *fix_prop = malloc(len);
308 char *orig_prop = strdup(proposal);
309 char *cp, *tmp;
djm@openbsd.org312d2f22018-07-04 13:49:31 +0000310 int r;
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000311
jsg@openbsd.orgb2afdaf2017-02-15 23:38:31 +0000312 if (fix_prop == NULL || orig_prop == NULL) {
313 free(orig_prop);
314 free(fix_prop);
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000315 return NULL;
jsg@openbsd.orgb2afdaf2017-02-15 23:38:31 +0000316 }
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000317
318 tmp = orig_prop;
319 *fix_prop = '\0';
320 while ((cp = strsep(&tmp, ",")) != NULL) {
djm@openbsd.org312d2f22018-07-04 13:49:31 +0000321 r = match_pattern_list(cp, filter, 0);
322 if ((blacklist && r != 1) || (!blacklist && r == 1)) {
djm@openbsd.org68bc8cf2017-02-03 23:01:19 +0000323 if (*fix_prop != '\0')
324 strlcat(fix_prop, ",", len);
325 strlcat(fix_prop, cp, len);
326 }
327 }
328 free(orig_prop);
329 return fix_prop;
330}
331
djm@openbsd.org312d2f22018-07-04 13:49:31 +0000332/*
333 * Filters a comma-separated list of strings, excluding any entry matching
334 * the 'filter' pattern list. Caller must free returned string.
335 */
336char *
337match_filter_blacklist(const char *proposal, const char *filter)
338{
339 return filter_list(proposal, filter, 1);
340}
341
342/*
343 * Filters a comma-separated list of strings, including only entries matching
344 * the 'filter' pattern list. Caller must free returned string.
345 */
346char *
347match_filter_whitelist(const char *proposal, const char *filter)
348{
349 return filter_list(proposal, filter, 0);
350}