351 lines
9.1 KiB
C
351 lines
9.1 KiB
C
/* $OpenBSD: match.c,v 1.38 2018/07/04 13:49:31 djm Exp $ */
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/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* Simple pattern matching, with '*' and '?' as wildcards.
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*/
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <ctype.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include "xmalloc.h"
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#include "match.h"
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#include "misc.h"
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/*
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* Returns true if the given string matches the pattern (which may contain ?
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* and * as wildcards), and zero if it does not match.
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*/
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int
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match_pattern(const char *s, const char *pattern)
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{
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for (;;) {
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/* If at end of pattern, accept if also at end of string. */
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if (!*pattern)
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return !*s;
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if (*pattern == '*') {
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/* Skip the asterisk. */
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pattern++;
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/* If at end of pattern, accept immediately. */
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if (!*pattern)
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return 1;
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/* If next character in pattern is known, optimize. */
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if (*pattern != '?' && *pattern != '*') {
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/*
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* Look instances of the next character in
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* pattern, and try to match starting from
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* those.
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*/
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for (; *s; s++)
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if (*s == *pattern &&
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match_pattern(s + 1, pattern + 1))
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return 1;
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/* Failed. */
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return 0;
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}
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/*
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* Move ahead one character at a time and try to
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* match at each position.
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*/
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for (; *s; s++)
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if (match_pattern(s, pattern))
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return 1;
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/* Failed. */
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return 0;
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}
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/*
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* There must be at least one more character in the string.
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* If we are at the end, fail.
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*/
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if (!*s)
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return 0;
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/* Check if the next character of the string is acceptable. */
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if (*pattern != '?' && *pattern != *s)
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return 0;
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/* Move to the next character, both in string and in pattern. */
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s++;
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pattern++;
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}
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/* NOTREACHED */
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}
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/*
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* Tries to match the string against the
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* comma-separated sequence of subpatterns (each possibly preceded by ! to
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* indicate negation). Returns -1 if negation matches, 1 if there is
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* a positive match, 0 if there is no match at all.
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*/
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int
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match_pattern_list(const char *string, const char *pattern, int dolower)
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{
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char sub[1024];
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int negated;
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int got_positive;
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u_int i, subi, len = strlen(pattern);
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got_positive = 0;
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for (i = 0; i < len;) {
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/* Check if the subpattern is negated. */
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if (pattern[i] == '!') {
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negated = 1;
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i++;
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} else
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negated = 0;
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/*
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* Extract the subpattern up to a comma or end. Convert the
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* subpattern to lowercase.
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*/
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for (subi = 0;
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i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
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subi++, i++)
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sub[subi] = dolower && isupper((u_char)pattern[i]) ?
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tolower((u_char)pattern[i]) : pattern[i];
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/* If subpattern too long, return failure (no match). */
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if (subi >= sizeof(sub) - 1)
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return 0;
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/* If the subpattern was terminated by a comma, then skip it. */
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if (i < len && pattern[i] == ',')
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i++;
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/* Null-terminate the subpattern. */
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sub[subi] = '\0';
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/* Try to match the subpattern against the string. */
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if (match_pattern(string, sub)) {
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if (negated)
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return -1; /* Negative */
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else
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got_positive = 1; /* Positive */
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}
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}
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/*
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* Return success if got a positive match. If there was a negative
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* match, we have already returned -1 and never get here.
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*/
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return got_positive;
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}
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/*
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* Tries to match the host name (which must be in all lowercase) against the
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* comma-separated sequence of subpatterns (each possibly preceded by ! to
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* indicate negation). Returns -1 if negation matches, 1 if there is
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* a positive match, 0 if there is no match at all.
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*/
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int
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match_hostname(const char *host, const char *pattern)
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{
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char *hostcopy = xstrdup(host);
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int r;
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lowercase(hostcopy);
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r = match_pattern_list(hostcopy, pattern, 1);
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free(hostcopy);
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return r;
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}
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/*
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* returns 0 if we get a negative match for the hostname or the ip
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* or if we get no match at all. returns -1 on error, or 1 on
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* successful match.
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*/
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int
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match_host_and_ip(const char *host, const char *ipaddr,
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const char *patterns)
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{
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int mhost, mip;
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if ((mip = addr_match_list(ipaddr, patterns)) == -2)
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return -1; /* error in ipaddr match */
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else if (host == NULL || ipaddr == NULL || mip == -1)
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return 0; /* negative ip address match, or testing pattern */
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/* negative hostname match */
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if ((mhost = match_hostname(host, patterns)) == -1)
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return 0;
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/* no match at all */
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if (mhost == 0 && mip == 0)
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return 0;
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return 1;
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}
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/*
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* Match user, user@host_or_ip, user@host_or_ip_list against pattern.
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* If user, host and ipaddr are all NULL then validate pattern/
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* Returns -1 on invalid pattern, 0 on no match, 1 on match.
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*/
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int
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match_user(const char *user, const char *host, const char *ipaddr,
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const char *pattern)
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{
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char *p, *pat;
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int ret;
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/* test mode */
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if (user == NULL && host == NULL && ipaddr == NULL) {
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if ((p = strchr(pattern, '@')) != NULL &&
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match_host_and_ip(NULL, NULL, p + 1) < 0)
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return -1;
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return 0;
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}
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if ((p = strchr(pattern,'@')) == NULL)
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return match_pattern(user, pattern);
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pat = xstrdup(pattern);
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p = strchr(pat, '@');
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*p++ = '\0';
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if ((ret = match_pattern(user, pat)) == 1)
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ret = match_host_and_ip(host, ipaddr, p);
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free(pat);
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return ret;
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}
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/*
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* Returns first item from client-list that is also supported by server-list,
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* caller must free the returned string.
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*/
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#define MAX_PROP 40
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#define SEP ","
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char *
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match_list(const char *client, const char *server, u_int *next)
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{
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char *sproposals[MAX_PROP];
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char *c, *s, *p, *ret, *cp, *sp;
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int i, j, nproposals;
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c = cp = xstrdup(client);
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s = sp = xstrdup(server);
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for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
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(p = strsep(&sp, SEP)), i++) {
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if (i < MAX_PROP)
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sproposals[i] = p;
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else
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break;
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}
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nproposals = i;
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for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
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(p = strsep(&cp, SEP)), i++) {
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for (j = 0; j < nproposals; j++) {
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if (strcmp(p, sproposals[j]) == 0) {
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ret = xstrdup(p);
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if (next != NULL)
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*next = (cp == NULL) ?
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strlen(c) : (u_int)(cp - c);
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free(c);
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free(s);
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return ret;
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}
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}
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}
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if (next != NULL)
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*next = strlen(c);
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free(c);
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free(s);
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return NULL;
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}
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/*
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* Filter proposal using pattern-list filter.
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* "blacklist" determines sense of filter:
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* non-zero indicates that items matching filter should be excluded.
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* zero indicates that only items matching filter should be included.
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* returns NULL on allocation error, otherwise caller must free result.
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*/
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static char *
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filter_list(const char *proposal, const char *filter, int blacklist)
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{
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size_t len = strlen(proposal) + 1;
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char *fix_prop = malloc(len);
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char *orig_prop = strdup(proposal);
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char *cp, *tmp;
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int r;
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if (fix_prop == NULL || orig_prop == NULL) {
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free(orig_prop);
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free(fix_prop);
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return NULL;
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}
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tmp = orig_prop;
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*fix_prop = '\0';
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while ((cp = strsep(&tmp, ",")) != NULL) {
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r = match_pattern_list(cp, filter, 0);
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if ((blacklist && r != 1) || (!blacklist && r == 1)) {
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if (*fix_prop != '\0')
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strlcat(fix_prop, ",", len);
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strlcat(fix_prop, cp, len);
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}
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}
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free(orig_prop);
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return fix_prop;
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}
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/*
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* Filters a comma-separated list of strings, excluding any entry matching
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* the 'filter' pattern list. Caller must free returned string.
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*/
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char *
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match_filter_blacklist(const char *proposal, const char *filter)
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{
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return filter_list(proposal, filter, 1);
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}
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/*
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* Filters a comma-separated list of strings, including only entries matching
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* the 'filter' pattern list. Caller must free returned string.
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*/
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char *
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match_filter_whitelist(const char *proposal, const char *filter)
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{
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return filter_list(proposal, filter, 0);
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}
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