crypto/openssh-3.9p1/match.c

   1 /*
   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.
   6  *
   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".
  12  */
  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  */
  36
  37 #include "includes.h"
  38 RCSID("$OpenBSD: match.c,v 1.19 2002/03/01 13:12:10 markus Exp $");
  39
  40 #include "match.h"
  41 #include "xmalloc.h"
  42
  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  */
  47
  48 int
  49 match_pattern(const char *s, const char *pattern)
  50 {
  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 != '*') {
  66                                 /*
  67                                  * Look instances of the next character in
  68                                  * pattern, and try to match starting from
  69                                  * those.
  70                                  */
  71                                 for (; *s; s++)
  72                                         if (*s == *pattern &&
  73                                             match_pattern(s + 1, pattern + 1))
  74                                                 return 1;
  75                                 /* Failed. */
  76                                 return 0;
  77                         }
  78                         /*
  79                          * Move ahead one character at a time and try to
  80                          * match at each position.
  81                          */
  82                         for (; *s; s++)
  83                                 if (match_pattern(s, pattern))
  84                                         return 1;
  85                         /* Failed. */
  86                         return 0;
  87                 }
  88                 /*
  89                  * There must be at least one more character in the string.
  90                  * If we are at the end, fail.
  91                  */
  92                 if (!*s)
  93                         return 0;
  94
  95                 /* Check if the next character of the string is acceptable. */
  96                 if (*pattern != '?' && *pattern != *s)
  97                         return 0;
  98
  99                 /* Move to the next character, both in string and in pattern. */
 100                 s++;
 101                 pattern++;
 102         }
 103         /* NOTREACHED */
 104 }
 105
 106 /*
 107  * Tries to match the string against the
 108  * comma-separated sequence of subpatterns (each possibly preceded by ! to
 109  * indicate negation).  Returns -1 if negation matches, 1 if there is
 110  * a positive match, 0 if there is no match at all.
 111  */
 112
 113 int
 114 match_pattern_list(const char *string, const char *pattern, u_int len,
 115     int dolower)
 116 {
 117         char sub[1024];
 118         int negated;
 119         int got_positive;
 120         u_int i, subi;
 121
 122         got_positive = 0;
 123         for (i = 0; i < len;) {
 124                 /* Check if the subpattern is negated. */
 125                 if (pattern[i] == '!') {
 126                         negated = 1;
 127                         i++;
 128                 } else
 129                         negated = 0;
 130
 131                 /*
 132                  * Extract the subpattern up to a comma or end.  Convert the
 133                  * subpattern to lowercase.
 134                  */
 135                 for (subi = 0;
 136                     i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
 137                     subi++, i++)
 138                         sub[subi] = dolower && isupper(pattern[i]) ?
 139                             tolower(pattern[i]) : pattern[i];
 140                 /* If subpattern too long, return failure (no match). */
 141                 if (subi >= sizeof(sub) - 1)
 142                         return 0;
 143
 144                 /* If the subpattern was terminated by a comma, skip the comma. */
 145                 if (i < len && pattern[i] == ',')
 146                         i++;
 147
 148                 /* Null-terminate the subpattern. */
 149                 sub[subi] = '\0';
 150
 151                 /* Try to match the subpattern against the string. */
 152                 if (match_pattern(string, sub)) {
 153                         if (negated)
 154                                 return -1;              /* Negative */
 155                         else
 156                                 got_positive = 1;       /* Positive */
 157                 }
 158         }
 159
 160         /*
 161          * Return success if got a positive match.  If there was a negative
 162          * match, we have already returned -1 and never get here.
 163          */
 164         return got_positive;
 165 }
 166
 167 /*
 168  * Tries to match the host name (which must be in all lowercase) against the
 169  * comma-separated sequence of subpatterns (each possibly preceded by ! to
 170  * indicate negation).  Returns -1 if negation matches, 1 if there is
 171  * a positive match, 0 if there is no match at all.
 172  */
 173 int
 174 match_hostname(const char *host, const char *pattern, u_int len)
 175 {
 176         return match_pattern_list(host, pattern, len, 1);
 177 }
 178
 179 /*
 180  * returns 0 if we get a negative match for the hostname or the ip
 181  * or if we get no match at all.  returns 1 otherwise.
 182  */
 183 int
 184 match_host_and_ip(const char *host, const char *ipaddr,
 185     const char *patterns)
 186 {
 187         int mhost, mip;
 188
 189         /* negative ipaddr match */
 190         if ((mip = match_hostname(ipaddr, patterns, strlen(patterns))) == -1)
 191                 return 0;
 192         /* negative hostname match */
 193         if ((mhost = match_hostname(host, patterns, strlen(patterns))) == -1)
 194                 return 0;
 195         /* no match at all */
 196         if (mhost == 0 && mip == 0)
 197                 return 0;
 198         return 1;
 199 }
 200
 201 /*
 202  * match user, user@host_or_ip, user@host_or_ip_list against pattern
 203  */
 204 int
 205 match_user(const char *user, const char *host, const char *ipaddr,
 206     const char *pattern)
 207 {
 208         char *p, *pat;
 209         int ret;
 210
 211         if ((p = strchr(pattern,'@')) == NULL)
 212                 return match_pattern(user, pattern);
 213
 214         pat = xstrdup(pattern);
 215         p = strchr(pat, '@');
 216         *p++ = '\0';
 217
 218         if ((ret = match_pattern(user, pat)) == 1)
 219                 ret = match_host_and_ip(host, ipaddr, p);
 220         xfree(pat);
 221
 222         return ret;
 223 }
 224
 225 /*
 226  * Returns first item from client-list that is also supported by server-list,
 227  * caller must xfree() returned string.
 228  */
 229 #define MAX_PROP        40
 230 #define SEP     ","
 231 char *
 232 match_list(const char *client, const char *server, u_int *next)
 233 {
 234         char *sproposals[MAX_PROP];
 235         char *c, *s, *p, *ret, *cp, *sp;
 236         int i, j, nproposals;
 237
 238         c = cp = xstrdup(client);
 239         s = sp = xstrdup(server);
 240
 241         for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
 242             (p = strsep(&sp, SEP)), i++) {
 243                 if (i < MAX_PROP)
 244                         sproposals[i] = p;
 245                 else
 246                         break;
 247         }
 248         nproposals = i;
 249
 250         for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
 251             (p = strsep(&cp, SEP)), i++) {
 252                 for (j = 0; j < nproposals; j++) {
 253                         if (strcmp(p, sproposals[j]) == 0) {
 254                                 ret = xstrdup(p);
 255                                 if (next != NULL)
 256                                         *next = (cp == NULL) ?
 257                                             strlen(c) : cp - c;
 258                                 xfree(c);
 259                                 xfree(s);
 260                                 return ret;
 261                         }
 262                 }
 263         }
 264         if (next != NULL)
 265                 *next = strlen(c);
 266         xfree(c);
 267         xfree(s);
 268         return NULL;
 269 }