fnmatch.c

/*	$OpenBSD: fnmatch.c,v 1.15 2011/02/10 21:31:59 stsp Exp $	*/

/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2011, VMware, Inc.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of the VMware, Inc. nor the names of its contributors
 *       may be used to endorse or promote products derived from this software
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 VMWARE, INC. OR CONTRIBUTORS 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.
 */

/*
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 2008, 2016 Todd C. Miller <[email protected]>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* Authored by William A. Rowe Jr. <wrowe; apache.org, vmware.com>, April 2011
 *
 * Derived from The Open Group Base Specifications Issue 7, IEEE Std 1003.1-2008
 * as described in;
 *   http://pubs.opengroup.org/onlinepubs/9699919799/functions/fnmatch.html
 *
 * Filename pattern matches defined in section 2.13, "Pattern Matching Notation"
 * from chapter 2. "Shell Command Language"
 *   http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_13
 * where; 1. A bracket expression starting with an unquoted <circumflex> '^' 
 * character CONTINUES to specify a non-matching list; 2. an explicit <period> '.' 
 * in a bracket expression matching list, e.g. "[.abc]" does NOT match a leading 
 * <period> in a filename; 3. a <left-square-bracket> '[' which does not introduce
 * a valid bracket expression is treated as an ordinary character; 4. a differing
 * number of consecutive slashes within pattern and string will NOT match;
 * 5. a trailing '\' in FNM_ESCAPE mode is treated as an ordinary '\' character.
 *
 * Bracket expansion defined in section 9.3.5, "RE Bracket Expression",
 * from chapter 9, "Regular Expressions"
 *   http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05
 * with no support for collating symbols, equivalence class expressions or 
 * character class expressions.  A partial range expression with a leading 
 * hyphen following a valid range expression will match only the ordinary
 * <hyphen> and the ending character (e.g. "[a-m-z]" will match characters 
 * 'a' through 'm', a <hyphen> '-', or a 'z').
 *
 * Supports BSD extensions FNM_LEADING_DIR to match pattern to the end of one
 * path segment of string, and FNM_CASEFOLD to ignore alpha case.
 *
 * NOTE: Only POSIX/C single byte locales are correctly supported at this time.
 * Notably, non-POSIX locales with FNM_CASEFOLD produce undefined results,
 * particularly in ranges of mixed case (e.g. "[A-z]") or spanning alpha and
 * nonalpha characters within a range.
 *
 * XXX comments below indicate porting required for multi-byte character sets
 * and non-POSIX locale collation orders; requires mbr* APIs to track shift
 * state of pattern and string (rewinding pattern and string repeatedly).
 *
 * Certain parts of the code assume 0x00-0x3F are unique with any MBCS (e.g.
 * UTF-8, SHIFT-JIS, etc).  Any implementation allowing '\' as an alternate
 * path delimiter must be aware that 0x5C is NOT unique within SHIFT-JIS.
 */

#include <config.h>

#ifndef HAVE_FNMATCH

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

#include <sudo_compat.h>
#include <compat/charclass.h>
#include <compat/fnmatch.h>

#define	RANGE_MATCH	1
#define	RANGE_NOMATCH	0
#define	RANGE_ERROR	(-1)

static int
classmatch(const char *pattern, char test, int foldcase, const char **ep)
{
	const char * const mismatch = pattern;
	const char *colon;
	struct cclass *cc;
	int result = RANGE_NOMATCH;
	size_t len;

	if (pattern[0] != '[' || pattern[1] != ':') {
		*ep = mismatch;
		return RANGE_ERROR;
	}
	pattern += 2;

	if ((colon = strchr(pattern, ':')) == NULL || colon[1] != ']') {
		*ep = mismatch;
		return RANGE_ERROR;
	}
	*ep = colon + 2;
	len = (size_t)(colon - pattern);

	if (foldcase && strncmp(pattern, "upper:]", 7) == 0)
		pattern = "lower:]";
	for (cc = cclasses; cc->name != NULL; cc++) {
		if (!strncmp(pattern, cc->name, len) && cc->name[len] == '\0') {
			if (cc->isctype((unsigned char)test))
				result = RANGE_MATCH;
			break;
		}
	}
	if (cc->name == NULL) {
		/* invalid character class, treat as normal text */
		*ep = mismatch;
		result = RANGE_ERROR;
	}
	return result;
}

/* Most MBCS/collation/case issues handled here.  Wildcard '*' is not handled.
 * EOS '\0' and the FNM_PATHNAME '/' delimiters are not advanced over, 
 * however the "\/" sequence is advanced to '/'.
 *
 * Both pattern and string are **char to support pointer increment of arbitrary
 * multibyte characters for the given locale, in a later iteration of this code
 */
static int fnmatch_ch(const char **pattern, const char **string, int flags)
{
    const char * const mismatch = *pattern;
    const int nocase = !!(flags & FNM_CASEFOLD);
    const int escape = !(flags & FNM_NOESCAPE);
    const int slash = !!(flags & FNM_PATHNAME);
    int result = FNM_NOMATCH;
    const char *startch;
    int negate;

    if (**pattern == '[')
    {
        ++*pattern;

        /* Handle negation, either leading ! or ^ operators (never both) */
        negate = ((**pattern == '!') || (**pattern == '^'));
        if (negate)
            ++*pattern;

        /* ']' is an ordinary character at the start of the range pattern */
        if (**pattern == ']')
            goto leadingclosebrace;

        while (**pattern)
        {
            if (**pattern == ']') {
                ++*pattern;
                /* XXX: Fix for MBCS character width */
                ++*string;
                return (result ^ negate);
            }

            if (escape && (**pattern == '\\')) {
                ++*pattern;

                /* Patterns must be terminated with ']', not EOS */
                if (!**pattern)
                    break;
            }

            /* Patterns must be terminated with ']' not '/' */
            if (slash && (**pattern == '/'))
                break;

            /* Match character classes. */
            switch (classmatch(*pattern, **string, nocase, pattern)) {
	    case RANGE_MATCH:
                result = 0;
                continue;
	    case RANGE_NOMATCH:
		/* Valid character class but no match. */
                continue;
	    default:
		/* Not a valid character class. */
		break;
	    }
            if (!**pattern)
                break;

leadingclosebrace:
            /* Look at only well-formed range patterns; 
             * "x-]" is not allowed unless escaped ("x-\]")
             * XXX: Fix for locale/MBCS character width
             */
            if (((*pattern)[1] == '-') && ((*pattern)[2] != ']'))
            {
                startch = *pattern;
                *pattern += (escape && ((*pattern)[2] == '\\')) ? 3 : 2;

                /* NOT a properly balanced [expr] pattern, EOS terminated 
                 * or ranges containing a slash in FNM_PATHNAME mode pattern
                 * fall out to the rewind and test '[' literal code path
                 */
                if (!**pattern || (slash && (**pattern == '/')))
                    break;

                /* XXX: handle locale/MBCS comparison, advance by MBCS char width */
                if ((**string >= *startch) && (**string <= **pattern))
                    result = 0;
                else if (nocase && (isupper((unsigned char)**string) ||
				    isupper((unsigned char)*startch) ||
				    isupper((unsigned char)**pattern))
                            && (tolower((unsigned char)**string) >= tolower((unsigned char)*startch)) 
                            && (tolower((unsigned char)**string) <= tolower((unsigned char)**pattern)))
                    result = 0;

                ++*pattern;
                continue;
            }

            /* XXX: handle locale/MBCS comparison, advance by MBCS char width */
            if ((**string == **pattern))
                result = 0;
            else if (nocase && (isupper((unsigned char)**string) ||
				isupper((unsigned char)**pattern))
                            && (tolower((unsigned char)**string) == tolower((unsigned char)**pattern)))
                result = 0;

            ++*pattern;
        }

        /* NOT a properly balanced [expr] pattern; Rewind
         * and reset result to test '[' literal
         */
        *pattern = mismatch;
        result = FNM_NOMATCH;
    }
    else if (**pattern == '?') {
        /* Optimize '?' match before unescaping **pattern */
        if (!**string || (slash && (**string == '/')))
            return FNM_NOMATCH;
        result = 0;
        goto fnmatch_ch_success;
    }
    else if (escape && (**pattern == '\\') && (*pattern)[1]) {
        ++*pattern;
    }

    /* XXX: handle locale/MBCS comparison, advance by the MBCS char width */
    if (**string == **pattern)
        result = 0;
    else if (nocase && (isupper((unsigned char)**string) || isupper((unsigned char)**pattern))
                    && (tolower((unsigned char)**string) == tolower((unsigned char)**pattern)))
        result = 0;

    /* Refuse to advance over trailing slash or nulls
     */
    if (!**string || !**pattern || (slash && ((**string == '/') || (**pattern == '/'))))
        return result;

fnmatch_ch_success:
    ++*pattern;
    ++*string;
    return result;
}

int sudo_fnmatch(const char *pattern, const char *string, int flags)
{
    static const char dummystring[2] = {' ', 0};
    const int escape = !(flags & FNM_NOESCAPE);
    const int slash = !!(flags & FNM_PATHNAME);
    const int leading_dir = !!(flags & FNM_LEADING_DIR);
    const char *strendseg;
    const char *dummyptr;
    const char *matchptr;
    int wild;
    /* For '*' wild processing only; suppress 'used before initialization'
     * warnings with dummy initialization values;
     */
    const char *strstartseg = NULL;
    const char *mismatch = NULL;
    int matchlen = 0;

    if (*pattern == '*')
        goto firstsegment;

    while (*pattern && *string)
    {
        /* Pre-decode "\/" which has no special significance, and
         * match balanced slashes, starting a new segment pattern
         */
        if (slash && escape && (*pattern == '\\') && (pattern[1] == '/'))
            ++pattern;
        if (slash && (*pattern == '/') && (*string == '/')) {
            ++pattern;
            ++string;
        }            

firstsegment:
        /* At the beginning of each segment, validate leading period behavior.
         */
        if ((flags & FNM_PERIOD) && (*string == '.'))
        {
            if (*pattern == '.')
                ++pattern;
            else if (escape && (*pattern == '\\') && (pattern[1] == '.'))
                pattern += 2;
            else
                return FNM_NOMATCH;
            ++string;
        }

        /* Determine the end of string segment
         *
         * Presumes '/' character is unique, not composite in any MBCS encoding
         */
        if (slash) {
            strendseg = strchr(string, '/');
            if (!strendseg)
                strendseg = strchr(string, '\0');
        }
        else {
            strendseg = strchr(string, '\0');
        }

        /* Allow pattern '*' to be consumed even with no remaining string to match
         */
        while (*pattern)
        {
            if ((string > strendseg)
                || ((string == strendseg) && (*pattern != '*')))
                break;

            if (slash && ((*pattern == '/')
                           || (escape && (*pattern == '\\')
                                      && (pattern[1] == '/'))))
                break;

            /* Reduce groups of '*' and '?' to n '?' matches
             * followed by one '*' test for simplicity
             */
            for (wild = 0; ((*pattern == '*') || (*pattern == '?')); ++pattern)
            {
                if (*pattern == '*') {
                    wild = 1;
                }
                else if (string < strendseg) {  /* && (*pattern == '?') */
                    /* XXX: Advance 1 char for MBCS locale */
                    ++string;
                }
                else {  /* (string >= strendseg) && (*pattern == '?') */
                    return FNM_NOMATCH;
                }
            }

            if (wild)
            {
                strstartseg = string;
                mismatch = pattern;

                /* Count fixed (non '*') char matches remaining in pattern
                 * excluding '/' (or "\/") and '*'
                 */
                for (matchptr = pattern, matchlen = 0; 1; ++matchlen)
                {
                    if ((*matchptr == '\0') 
                        || (slash && ((*matchptr == '/')
                                      || (escape && (*matchptr == '\\')
                                                 && (matchptr[1] == '/')))))
                    {
                        /* Compare precisely this many trailing string chars,
                         * the resulting match needs no wildcard loop
                         */
                        /* XXX: Adjust for MBCS */
                        if (string + matchlen > strendseg)
                            return FNM_NOMATCH;

                        string = strendseg - matchlen;
                        wild = 0;
                        break;
                    }

                    if (*matchptr == '*')
                    {
                        /* Ensure at least this many trailing string chars remain
                         * for the first comparison
                         */
                        /* XXX: Adjust for MBCS */
                        if (string + matchlen > strendseg)
                            return FNM_NOMATCH;

                        /* Begin first wild comparison at the current position */
                        break;
                    }

                    /* Skip forward in pattern by a single character match
                     * Use a dummy fnmatch_ch() test to count one "[range]" escape
                     */ 
                    /* XXX: Adjust for MBCS */
                    if (escape && (*matchptr == '\\') && matchptr[1]) {
                        matchptr += 2;
                    }
                    else if (*matchptr == '[') {
                        dummyptr = dummystring;
                        fnmatch_ch(&matchptr, &dummyptr, flags);
                    }
                    else {
                        ++matchptr;
                    }
                }
            }

            /* Incrementally match string against the pattern
             */
            while (*pattern && (string < strendseg))
            {
                /* Success; begin a new wild pattern search
                 */
                if (*pattern == '*')
                    break;

                if (slash && ((*string == '/')
                              || (*pattern == '/')
                              || (escape && (*pattern == '\\')
                                         && (pattern[1] == '/'))))
                    break;

                /* Compare ch's (the pattern is advanced over "\/" to the '/',
                 * but slashes will mismatch, and are not consumed)
                 */
                if (!fnmatch_ch(&pattern, &string, flags))
                    continue;

                /* Failed to match, loop against next char offset of string segment 
                 * until not enough string chars remain to match the fixed pattern
                 */
                if (wild) {
                    /* XXX: Advance 1 char for MBCS locale */
                    string = ++strstartseg;
                    if (string + matchlen > strendseg)
                        return FNM_NOMATCH;

                    pattern = mismatch;
                    continue;
                }
                else
                    return FNM_NOMATCH;
            }
        }

        if (*string && !((slash || leading_dir) && (*string == '/')))
            return FNM_NOMATCH;

        if (*pattern && !(slash && ((*pattern == '/')
                                    || (escape && (*pattern == '\\')
                                               && (pattern[1] == '/')))))
            return FNM_NOMATCH;

        if (leading_dir && !*pattern && *string == '/')
            return 0;
    }

    /* Where both pattern and string are at EOS, declare success
     */
    if (!*string && !*pattern)
        return 0;

    /* pattern didn't match to the end of string */
    return FNM_NOMATCH;
}
#endif /* HAVE_FNMATCH */