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/*
* 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".
*/
#include "includes.h"
RCSID("$OpenBSD: match.c,v 1.9 2000/09/07 20:27:52 deraadt Exp $");
#include "ssh.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 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, unsigned int len)
{
char sub[1024];
int negated;
int got_positive;
unsigned 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] = 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 host name. */
if (match_pattern(host, 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;
}
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