/*

 * 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 "config.h"

#include <ctype.h>

#include <stdbool.h>

#include <sys/types.h>

#include "libssh/priv.h"

#define MAX_MATCH_RECURSION 32

/*

 * Returns true if the given string matches the pattern (which may contain ?

 * and * as wildcards), and zero if it does not match.

 */

static int match_pattern(const char *s, const char *pattern, size_t limit)

{

  bool had_asterisk = false;

  if (s == NULL || pattern == NULL || limit <= 0) {

    return 0;

  }

  for (;;) {

    /* If at end of pattern, accept if also at end of string. */

    if (*pattern == '\0') {

        return (*s == '\0');

    }

    while (*pattern == '*') {

      /* Skip the asterisk. */

      had_asterisk = true;

      pattern++;

    }

    if (had_asterisk) {

      /* If at end of pattern, accept immediately. */

      if (!*pattern)

        return 1;

      /* If next character in pattern is known, optimize. */

      if (*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, limit - 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, limit - 1)) {

          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 */

  return 0;

}

/*

 * 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,

    unsigned int len, int dolower) {

  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] = 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, MAX_MATCH_RECURSION)) {

      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, unsigned int len) {

  return match_pattern_list(host, pattern, len, 1);

}