summaryrefslogtreecommitdiffstats
path: root/match.c
blob: ca4d92c400a6bdc3448a3989b73e916a50f05d41 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * Simple pattern matching, with '*' and '?' as wildcards.
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 */
/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"
RCSID("$OpenBSD: match.c,v 1.15 2001/12/05 16:54:51 markus Exp $");

#include "match.h"
#include "xmalloc.h"

/*
 * Returns true if the given string matches the pattern (which may contain ?
 * and * as wildcards), and zero if it does not match.
 */

int
match_pattern(const char *s, const char *pattern)
{
	for (;;) {
		/* If at end of pattern, accept if also at end of string. */
		if (!*pattern)
			return !*s;

		if (*pattern == '*') {
			/* Skip the asterisk. */
			pattern++;

			/* If at end of pattern, accept immediately. */
			if (!*pattern)
				return 1;

			/* If next character in pattern is known, optimize. */
			if (*pattern != '?' && *pattern != '*') {
				/*
				 * Look instances of the next character in
				 * pattern, and try to match starting from
				 * those.
				 */
				for (; *s; s++)
					if (*s == *pattern &&
					    match_pattern(s + 1, pattern + 1))
						return 1;
				/* Failed. */
				return 0;
			}
			/*
			 * Move ahead one character at a time and try to
			 * match at each position.
			 */
			for (; *s; s++)
				if (match_pattern(s, pattern))
					return 1;
			/* Failed. */
			return 0;
		}
		/*
		 * There must be at least one more character in the string.
		 * If we are at the end, fail.
		 */
		if (!*s)
			return 0;

		/* Check if the next character of the string is acceptable. */
		if (*pattern != '?' && *pattern != *s)
			return 0;

		/* Move to the next character, both in string and in pattern. */
		s++;
		pattern++;
	}
	/* NOTREACHED */
}

/*
 * Tries to match the string against the
 * comma-separated sequence of subpatterns (each possibly preceded by ! to
 * indicate negation).  Returns -1 if negation matches, 1 if there is
 * a positive match, 0 if there is no match at all.
 */

int
match_pattern_list(const char *string, const char *pattern, u_int len,
    int dolower)
{
	char sub[1024];
	int negated;
	int got_positive;
	u_int i, subi;

	got_positive = 0;
	for (i = 0; i < len;) {
		/* Check if the subpattern is negated. */
		if (pattern[i] == '!') {
			negated = 1;
			i++;
		} else
			negated = 0;

		/*
		 * Extract the subpattern up to a comma or end.  Convert the
		 * subpattern to lowercase.
		 */
		for (subi = 0;
		     i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
		     subi++, i++)
			sub[subi] = dolower && isupper(pattern[i]) ?
			     tolower(pattern[i]) : pattern[i];
		/* If subpattern too long, return failure (no match). */
		if (subi >= sizeof(sub) - 1)
			return 0;

		/* If the subpattern was terminated by a comma, skip the comma. */
		if (i < len && pattern[i] == ',')
			i++;

		/* Null-terminate the subpattern. */
		sub[subi] = '\0';

		/* Try to match the subpattern against the string. */
		if (match_pattern(string, sub)) {
			if (negated)
				return -1;		/* Negative */
			else
				got_positive = 1;	/* Positive */
		}
	}

	/*
	 * Return success if got a positive match.  If there was a negative
	 * match, we have already returned -1 and never get here.
	 */
	return got_positive;
}

/*
 * Tries to match the host name (which must be in all lowercase) against the
 * comma-separated sequence of subpatterns (each possibly preceded by ! to
 * indicate negation).  Returns -1 if negation matches, 1 if there is
 * a positive match, 0 if there is no match at all.
 */
int
match_hostname(const char *host, const char *pattern, u_int len)
{
	return match_pattern_list(host, pattern, len, 1);
}

/*
 * returns 0 if we get a negative match for the hostname or the ip
 * or if we get no match at all.  returns 1 otherwise.
 */
int
match_host_and_ip(const char *host, const char *ipaddr,
    const char *patterns)
{
	int mhost, mip;

	/* negative ipaddr match */
	if ((mip = match_hostname(ipaddr, patterns, strlen(patterns))) == -1)
		return 0;
	/* negative hostname match */
	if ((mhost = match_hostname(host, patterns, strlen(patterns))) == -1)
		return 0;
	/* no match at all */
	if (mhost == 0 && mip == 0)
		return 0;
	return 1;
}

/*
 * match user, user@host_or_ip, user@host_or_ip_list against pattern
 */
int
match_user(const char *user, const char *host, const char *ipaddr,
    const char *pattern)
{
	char *p, *pat;
	int ret;

	if ((p = strchr(pattern,'@')) == NULL)
		return match_pattern(user, pattern);

	pat = xstrdup(pattern);
	p = strchr(pat, '@');
	*p++ = '\0';

	if ((ret = match_pattern(user, pat)) == 1)
		ret = match_host_and_ip(host, ipaddr, p);
	xfree(pat);

	return ret;
}

/*
 * Returns first item from client-list that is also supported by server-list,
 * caller must xfree() returned string.
 */
#define	MAX_PROP	20
#define	SEP	","
char *
match_list(const char *client, const char *server, u_int *next)
{
	char *sproposals[MAX_PROP];
	char *c, *s, *p, *ret, *cp, *sp;
	int i, j, nproposals;

	c = cp = xstrdup(client);
	s = sp = xstrdup(server);

	for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
	     (p = strsep(&sp, SEP)), i++) {
		if (i < MAX_PROP)
			sproposals[i] = p;
		else
			break;
	}
	nproposals = i;

	for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
	     (p = strsep(&cp, SEP)), i++) {
		for (j = 0; j < nproposals; j++) {
			if (strcmp(p, sproposals[j]) == 0) {
				ret = xstrdup(p);
				if (next != NULL)
					*next = (cp == NULL) ?
					    strlen(c) : cp - c;
				xfree(c);
				xfree(s);
				return ret;
			}
		}
	}
	if (next != NULL)
		*next = strlen(c);
	xfree(c);
	xfree(s);
	return NULL;
}