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Annotation of src/usr.bin/ssh/match.c, Revision 1.13

1.1       deraadt     1: /*
1.3       deraadt     2:  * Author: Tatu Ylonen <ylo@cs.hut.fi>
                      3:  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                      4:  *                    All rights reserved
                      5:  * Simple pattern matching, with '*' and '?' as wildcards.
1.6       markus      6:  *
1.9       deraadt     7:  * As far as I am concerned, the code I have written for this software
                      8:  * can be used freely for any purpose.  Any derived versions of this
                      9:  * software must be clearly marked as such, and if the derived work is
                     10:  * incompatible with the protocol description in the RFC file, it must be
                     11:  * called by a name other than "ssh" or "Secure Shell".
1.3       deraadt    12:  */
1.12      markus     13: /*
                     14:  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
                     15:  *
                     16:  * Redistribution and use in source and binary forms, with or without
                     17:  * modification, are permitted provided that the following conditions
                     18:  * are met:
                     19:  * 1. Redistributions of source code must retain the above copyright
                     20:  *    notice, this list of conditions and the following disclaimer.
                     21:  * 2. Redistributions in binary form must reproduce the above copyright
                     22:  *    notice, this list of conditions and the following disclaimer in the
                     23:  *    documentation and/or other materials provided with the distribution.
                     24:  *
                     25:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
                     26:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     27:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     28:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
                     29:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
                     30:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
                     31:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
                     32:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     33:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
                     34:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                     35:  */
1.1       deraadt    36:
                     37: #include "includes.h"
1.13    ! markus     38: RCSID("$OpenBSD: match.c,v 1.12 2001/03/10 17:51:04 markus Exp $");
1.1       deraadt    39:
1.11      markus     40: #include "match.h"
1.12      markus     41: #include "xmalloc.h"
1.1       deraadt    42:
1.4       markus     43: /*
                     44:  * Returns true if the given string matches the pattern (which may contain ?
                     45:  * and * as wildcards), and zero if it does not match.
                     46:  */
1.2       markus     47:
1.6       markus     48: int
1.2       markus     49: match_pattern(const char *s, const char *pattern)
1.1       deraadt    50: {
1.2       markus     51:        for (;;) {
                     52:                /* If at end of pattern, accept if also at end of string. */
                     53:                if (!*pattern)
                     54:                        return !*s;
                     55:
                     56:                if (*pattern == '*') {
                     57:                        /* Skip the asterisk. */
                     58:                        pattern++;
                     59:
                     60:                        /* If at end of pattern, accept immediately. */
                     61:                        if (!*pattern)
                     62:                                return 1;
                     63:
                     64:                        /* If next character in pattern is known, optimize. */
                     65:                        if (*pattern != '?' && *pattern != '*') {
1.4       markus     66:                                /*
                     67:                                 * Look instances of the next character in
                     68:                                 * pattern, and try to match starting from
                     69:                                 * those.
                     70:                                 */
1.2       markus     71:                                for (; *s; s++)
                     72:                                        if (*s == *pattern &&
                     73:                                            match_pattern(s + 1, pattern + 1))
                     74:                                                return 1;
                     75:                                /* Failed. */
                     76:                                return 0;
                     77:                        }
1.4       markus     78:                        /*
                     79:                         * Move ahead one character at a time and try to
                     80:                         * match at each position.
                     81:                         */
1.2       markus     82:                        for (; *s; s++)
                     83:                                if (match_pattern(s, pattern))
                     84:                                        return 1;
                     85:                        /* Failed. */
                     86:                        return 0;
                     87:                }
1.4       markus     88:                /*
                     89:                 * There must be at least one more character in the string.
                     90:                 * If we are at the end, fail.
                     91:                 */
1.2       markus     92:                if (!*s)
                     93:                        return 0;
                     94:
1.4       markus     95:                /* Check if the next character of the string is acceptable. */
1.2       markus     96:                if (*pattern != '?' && *pattern != *s)
                     97:                        return 0;
                     98:
1.4       markus     99:                /* Move to the next character, both in string and in pattern. */
1.2       markus    100:                s++;
                    101:                pattern++;
                    102:        }
                    103:        /* NOTREACHED */
1.5       markus    104: }
                    105:
                    106: /*
                    107:  * Tries to match the host name (which must be in all lowercase) against the
                    108:  * comma-separated sequence of subpatterns (each possibly preceded by ! to
1.7       markus    109:  * indicate negation).  Returns -1 if negation matches, 1 if there is
                    110:  * a positive match, 0 if there is no match at all.
1.5       markus    111:  */
                    112:
                    113: int
1.10      markus    114: match_hostname(const char *host, const char *pattern, u_int len)
1.5       markus    115: {
                    116:        char sub[1024];
                    117:        int negated;
                    118:        int got_positive;
1.10      markus    119:        u_int i, subi;
1.5       markus    120:
                    121:        got_positive = 0;
                    122:        for (i = 0; i < len;) {
                    123:                /* Check if the subpattern is negated. */
                    124:                if (pattern[i] == '!') {
                    125:                        negated = 1;
                    126:                        i++;
                    127:                } else
                    128:                        negated = 0;
                    129:
                    130:                /*
                    131:                 * Extract the subpattern up to a comma or end.  Convert the
                    132:                 * subpattern to lowercase.
                    133:                 */
                    134:                for (subi = 0;
                    135:                     i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
                    136:                     subi++, i++)
                    137:                        sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i];
                    138:                /* If subpattern too long, return failure (no match). */
                    139:                if (subi >= sizeof(sub) - 1)
                    140:                        return 0;
                    141:
                    142:                /* If the subpattern was terminated by a comma, skip the comma. */
                    143:                if (i < len && pattern[i] == ',')
                    144:                        i++;
                    145:
                    146:                /* Null-terminate the subpattern. */
                    147:                sub[subi] = '\0';
                    148:
                    149:                /* Try to match the subpattern against the host name. */
                    150:                if (match_pattern(host, sub)) {
                    151:                        if (negated)
1.7       markus    152:                                return -1;              /* Negative */
1.5       markus    153:                        else
1.7       markus    154:                                got_positive = 1;       /* Positive */
1.5       markus    155:                }
                    156:        }
                    157:
                    158:        /*
                    159:         * Return success if got a positive match.  If there was a negative
1.7       markus    160:         * match, we have already returned -1 and never get here.
1.5       markus    161:         */
                    162:        return got_positive;
1.12      markus    163: }
                    164:
1.13    ! markus    165: /*
        !           166:  * returns 0 if we get a negative match for the hostname or the ip
        !           167:  * or if we get no match at all.  returns 1 otherwise.
        !           168:  */
        !           169: int
        !           170: match_host_and_ip(const char *host, const char *ipaddr,
        !           171:     const char *patterns)
        !           172: {
        !           173:        int mhost, mip;
1.12      markus    174:
1.13    ! markus    175:        /* negative ipaddr match */
        !           176:        if ((mip = match_hostname(ipaddr, patterns, strlen(patterns))) == -1)
        !           177:                return 0;
        !           178:        /* negative hostname match */
        !           179:        if ((mhost = match_hostname(host, patterns, strlen(patterns))) == -1)
        !           180:                return 0;
        !           181:        /* no match at all */
        !           182:        if (mhost == 0 && mip == 0)
        !           183:                return 0;
        !           184:        return 1;
        !           185: }
        !           186:
        !           187: /*
        !           188:  * Returns first item from client-list that is also supported by server-list,
        !           189:  * caller must xfree() returned string.
        !           190:  */
1.12      markus    191: #define        MAX_PROP        20
                    192: #define        SEP     ","
                    193: char *
                    194: match_list(const char *client, const char *server, u_int *next)
                    195: {
                    196:        char *sproposals[MAX_PROP];
                    197:        char *c, *s, *p, *ret, *cp, *sp;
                    198:        int i, j, nproposals;
                    199:
                    200:        c = cp = xstrdup(client);
                    201:        s = sp = xstrdup(server);
                    202:
                    203:        for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
                    204:             (p = strsep(&sp, SEP)), i++) {
                    205:                if (i < MAX_PROP)
                    206:                        sproposals[i] = p;
                    207:                else
                    208:                        break;
                    209:        }
                    210:        nproposals = i;
                    211:
                    212:        for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
                    213:             (p = strsep(&cp, SEP)), i++) {
                    214:                for (j = 0; j < nproposals; j++) {
                    215:                        if (strcmp(p, sproposals[j]) == 0) {
                    216:                                ret = xstrdup(p);
                    217:                                if (next != NULL)
                    218:                                        *next = (cp == NULL) ?
                    219:                                            strlen(c) : cp - c;
                    220:                                xfree(c);
                    221:                                xfree(s);
                    222:                                return ret;
                    223:                        }
                    224:                }
                    225:        }
                    226:        if (next != NULL)
                    227:                *next = strlen(c);
                    228:        xfree(c);
                    229:        xfree(s);
                    230:        return NULL;
1.1       deraadt   231: }