[openssh.git] / match.c

/* $OpenBSD: match.c,v 1.25 2006/07/22 20:48:23 stevesk Exp $ */
/*
 * 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"

#include <ctype.h>
#include <string.h>

#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]) ?
			    (char)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	40
#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) : (u_int)(cp - c);
				xfree(c);
				xfree(s);
				return ret;
			}
		}
	}
	if (next != NULL)
		*next = strlen(c);
	xfree(c);
	xfree(s);
	return NULL;
}
Commit	Line	Data
00146caa	1	/* $OpenBSD: match.c,v 1.25 2006/07/22 20:48:23 stevesk Exp $ */
8efc0c15	2	/*
5260325f	3	* Author: Tatu Ylonen <ylo@cs.hut.fi>
5260325f	4	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5260325f	5	* All rights reserved
5260325f	6	* Simple pattern matching, with '*' and '?' as wildcards.
6ae2364d	7	*
bcbf86ec	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".
5260325f	13	*/
cab80f75	14	/*
	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	*/
8efc0c15	37
8efc0c15	38	#include "includes.h"
b6438382	39
b6438382	40	#include <ctype.h>
00146caa	41	#include <string.h>
8efc0c15	42
42f11eb2	43	#include "match.h"
cab80f75	44	#include "xmalloc.h"
8efc0c15	45
aa3378df	46	/*
	47	* Returns true if the given string matches the pattern (which may contain ?
	48	* and * as wildcards), and zero if it does not match.
	49	*/
8efc0c15	50
6ae2364d	51	int
5260325f	52	match_pattern(const char s, const char pattern)
	53	{
	54	for (;;) {
	55	/* If at end of pattern, accept if also at end of string. */
	56	if (!*pattern)
	57	return !*s;
8efc0c15	58
5260325f	59	if (pattern == '') {
	60	/* Skip the asterisk. */
	61	pattern++;
8efc0c15	62
5260325f	63	/* If at end of pattern, accept immediately. */
	64	if (!*pattern)
	65	return 1;
8efc0c15	66
5260325f	67	/* If next character in pattern is known, optimize. */
5260325f	68	if (pattern != '?' && pattern != '*') {
aa3378df	69	/*
	70	* Look instances of the next character in
	71	* pattern, and try to match starting from
	72	* those.
	73	*/
5260325f	74	for (; *s; s++)
	75	if (s == pattern &&
	76	match_pattern(s + 1, pattern + 1))
	77	return 1;
	78	/* Failed. */
	79	return 0;
	80	}
aa3378df	81	/*
	82	* Move ahead one character at a time and try to
	83	* match at each position.
	84	*/
5260325f	85	for (; *s; s++)
	86	if (match_pattern(s, pattern))
	87	return 1;
	88	/* Failed. */
	89	return 0;
	90	}
aa3378df	91	/*
	92	* There must be at least one more character in the string.
	93	* If we are at the end, fail.
	94	*/
5260325f	95	if (!*s)
5260325f	96	return 0;
8efc0c15	97
aa3378df	98	/* Check if the next character of the string is acceptable. */
5260325f	99	if (pattern != '?' && pattern != *s)
5260325f	100	return 0;
8efc0c15	101
aa3378df	102	/* Move to the next character, both in string and in pattern. */
5260325f	103	s++;
	104	pattern++;
	105	}
	106	/* NOTREACHED */
8efc0c15	107	}
4fe2af09	108
4fe2af09	109	/*
6a92533a	110	* Tries to match the string against the
4fe2af09	111	* comma-separated sequence of subpatterns (each possibly preceded by ! to
fa649821	112	* indicate negation). Returns -1 if negation matches, 1 if there is
fa649821	113	* a positive match, 0 if there is no match at all.
4fe2af09	114	*/
	115
	116	int
6a92533a	117	match_pattern_list(const char string, const char pattern, u_int len,
6a92533a	118	int dolower)
4fe2af09	119	{
	120	char sub[1024];
	121	int negated;
	122	int got_positive;
1e3b8b07	123	u_int i, subi;
4fe2af09	124
	125	got_positive = 0;
	126	for (i = 0; i < len;) {
	127	/* Check if the subpattern is negated. */
	128	if (pattern[i] == '!') {
	129	negated = 1;
	130	i++;
	131	} else
	132	negated = 0;
	133
	134	/*
	135	* Extract the subpattern up to a comma or end. Convert the
	136	* subpattern to lowercase.
	137	*/
	138	for (subi = 0;
184eed6a	139	i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
184eed6a	140	subi++, i++)
6a92533a	141	sub[subi] = dolower && isupper(pattern[i]) ?
9555d258	142	(char)tolower(pattern[i]) : pattern[i];
4fe2af09	143	/* If subpattern too long, return failure (no match). */
	144	if (subi >= sizeof(sub) - 1)
	145	return 0;
	146
	147	/* If the subpattern was terminated by a comma, skip the comma. */
	148	if (i < len && pattern[i] == ',')
	149	i++;
	150
	151	/* Null-terminate the subpattern. */
	152	sub[subi] = '\0';
	153
6a92533a	154	/* Try to match the subpattern against the string. */
6a92533a	155	if (match_pattern(string, sub)) {
4fe2af09	156	if (negated)
fa649821	157	return -1; /* Negative */
4fe2af09	158	else
fa649821	159	got_positive = 1; /* Positive */
4fe2af09	160	}
	161	}
	162
	163	/*
	164	* Return success if got a positive match. If there was a negative
fa649821	165	* match, we have already returned -1 and never get here.
4fe2af09	166	*/
	167	return got_positive;
	168	}
cab80f75	169
6a92533a	170	/*
	171	* Tries to match the host name (which must be in all lowercase) against the
	172	* comma-separated sequence of subpatterns (each possibly preceded by ! to
	173	* indicate negation). Returns -1 if negation matches, 1 if there is
	174	* a positive match, 0 if there is no match at all.
	175	*/
	176	int
	177	match_hostname(const char host, const char pattern, u_int len)
	178	{
	179	return match_pattern_list(host, pattern, len, 1);
	180	}
	181
2cee8a25	182	/*
	183	* returns 0 if we get a negative match for the hostname or the ip
	184	* or if we get no match at all. returns 1 otherwise.
	185	*/
	186	int
	187	match_host_and_ip(const char host, const char ipaddr,
	188	const char *patterns)
	189	{
	190	int mhost, mip;
	191
	192	/* negative ipaddr match */
	193	if ((mip = match_hostname(ipaddr, patterns, strlen(patterns))) == -1)
	194	return 0;
	195	/* negative hostname match */
	196	if ((mhost = match_hostname(host, patterns, strlen(patterns))) == -1)
	197	return 0;
	198	/* no match at all */
	199	if (mhost == 0 && mip == 0)
	200	return 0;
	201	return 1;
	202	}
cab80f75	203
80f8f24f	204	/*
	205	* match user, user@host_or_ip, user@host_or_ip_list against pattern
	206	*/
	207	int
6805fc56	208	match_user(const char user, const char host, const char *ipaddr,
80f8f24f	209	const char *pattern)
	210	{
	211	char p, pat;
	212	int ret;
	213
	214	if ((p = strchr(pattern,'@')) == NULL)
	215	return match_pattern(user, pattern);
	216
	217	pat = xstrdup(pattern);
	218	p = strchr(pat, '@');
	219	*p++ = '\0';
	220
	221	if ((ret = match_pattern(user, pat)) == 1)
6805fc56	222	ret = match_host_and_ip(host, ipaddr, p);
80f8f24f	223	xfree(pat);
	224
	225	return ret;
	226	}
	227
2cee8a25	228	/*
	229	* Returns first item from client-list that is also supported by server-list,
	230	* caller must xfree() returned string.
	231	*/
fa869228	232	#define MAX_PROP 40
cab80f75	233	#define SEP ","
	234	char *
	235	match_list(const char client, const char server, u_int *next)
	236	{
	237	char *sproposals[MAX_PROP];
	238	char c, s, p, ret, cp, sp;
	239	int i, j, nproposals;
	240
	241	c = cp = xstrdup(client);
	242	s = sp = xstrdup(server);
	243
	244	for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
184eed6a	245	(p = strsep(&sp, SEP)), i++) {
cab80f75	246	if (i < MAX_PROP)
	247	sproposals[i] = p;
	248	else
	249	break;
	250	}
	251	nproposals = i;
	252
	253	for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
184eed6a	254	(p = strsep(&cp, SEP)), i++) {
cab80f75	255	for (j = 0; j < nproposals; j++) {
	256	if (strcmp(p, sproposals[j]) == 0) {
	257	ret = xstrdup(p);
	258	if (next != NULL)
	259	*next = (cp == NULL) ?
2ceb8101	260	strlen(c) : (u_int)(cp - c);
cab80f75	261	xfree(c);
	262	xfree(s);
	263	return ret;
	264	}
	265	}
	266	}
	267	if (next != NULL)
	268	*next = strlen(c);
	269	xfree(c);
	270	xfree(s);
	271	return NULL;
	272	}