1 /* $NetBSD: match.c,v 1.13 2020/02/27 00:24:40 christos Exp $ */ 2 /* $OpenBSD: match.c,v 1.41 2019/11/13 04:47:52 deraadt Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * Simple pattern matching, with '*' and '?' as wildcards. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 */ 15 /* 16 * Copyright (c) 2000 Markus Friedl. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include "includes.h" 40 __RCSID("$NetBSD: match.c,v 1.13 2020/02/27 00:24:40 christos Exp $"); 41 #include <sys/types.h> 42 43 #include <ctype.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <stdarg.h> 47 #include <stdio.h> 48 49 #include "xmalloc.h" 50 #include "match.h" 51 #include "misc.h" 52 53 /* 54 * Returns true if the given string matches the pattern (which may contain ? 55 * and * as wildcards), and zero if it does not match. 56 */ 57 58 int 59 match_pattern(const char *s, const char *pattern) 60 { 61 for (;;) { 62 /* If at end of pattern, accept if also at end of string. */ 63 if (!*pattern) 64 return !*s; 65 66 if (*pattern == '*') { 67 /* Skip the asterisk. */ 68 pattern++; 69 70 /* If at end of pattern, accept immediately. */ 71 if (!*pattern) 72 return 1; 73 74 /* If next character in pattern is known, optimize. */ 75 if (*pattern != '?' && *pattern != '*') { 76 /* 77 * Look instances of the next character in 78 * pattern, and try to match starting from 79 * those. 80 */ 81 for (; *s; s++) 82 if (*s == *pattern && 83 match_pattern(s + 1, pattern + 1)) 84 return 1; 85 /* Failed. */ 86 return 0; 87 } 88 /* 89 * Move ahead one character at a time and try to 90 * match at each position. 91 */ 92 for (; *s; s++) 93 if (match_pattern(s, pattern)) 94 return 1; 95 /* Failed. */ 96 return 0; 97 } 98 /* 99 * There must be at least one more character in the string. 100 * If we are at the end, fail. 101 */ 102 if (!*s) 103 return 0; 104 105 /* Check if the next character of the string is acceptable. */ 106 if (*pattern != '?' && *pattern != *s) 107 return 0; 108 109 /* Move to the next character, both in string and in pattern. */ 110 s++; 111 pattern++; 112 } 113 /* NOTREACHED */ 114 } 115 116 /* 117 * Tries to match the string against the 118 * comma-separated sequence of subpatterns (each possibly preceded by ! to 119 * indicate negation). Returns -1 if negation matches, 1 if there is 120 * a positive match, 0 if there is no match at all. 121 */ 122 int 123 match_pattern_list(const char *string, const char *pattern, int dolower) 124 { 125 char sub[1024]; 126 int negated; 127 int got_positive; 128 u_int i, subi, len = strlen(pattern); 129 130 got_positive = 0; 131 for (i = 0; i < len;) { 132 /* Check if the subpattern is negated. */ 133 if (pattern[i] == '!') { 134 negated = 1; 135 i++; 136 } else 137 negated = 0; 138 139 /* 140 * Extract the subpattern up to a comma or end. Convert the 141 * subpattern to lowercase. 142 */ 143 for (subi = 0; 144 i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; 145 subi++, i++) 146 sub[subi] = dolower && isupper((u_char)pattern[i]) ? 147 tolower((u_char)pattern[i]) : pattern[i]; 148 /* If subpattern too long, return failure (no match). */ 149 if (subi >= sizeof(sub) - 1) 150 return 0; 151 152 /* If the subpattern was terminated by a comma, then skip it. */ 153 if (i < len && pattern[i] == ',') 154 i++; 155 156 /* Null-terminate the subpattern. */ 157 sub[subi] = '\0'; 158 159 /* Try to match the subpattern against the string. */ 160 if (match_pattern(string, sub)) { 161 if (negated) 162 return -1; /* Negative */ 163 else 164 got_positive = 1; /* Positive */ 165 } 166 } 167 168 /* 169 * Return success if got a positive match. If there was a negative 170 * match, we have already returned -1 and never get here. 171 */ 172 return got_positive; 173 } 174 175 /* Match a list representing users or groups. */ 176 int 177 match_usergroup_pattern_list(const char *string, const char *pattern) 178 { 179 /* Case sensitive match */ 180 return match_pattern_list(string, pattern, 0); 181 } 182 183 /* 184 * Tries to match the host name (which must be in all lowercase) against the 185 * comma-separated sequence of subpatterns (each possibly preceded by ! to 186 * indicate negation). Returns -1 if negation matches, 1 if there is 187 * a positive match, 0 if there is no match at all. 188 */ 189 int 190 match_hostname(const char *host, const char *pattern) 191 { 192 char *hostcopy = xstrdup(host); 193 int r; 194 195 lowercase(hostcopy); 196 r = match_pattern_list(hostcopy, pattern, 1); 197 free(hostcopy); 198 return r; 199 } 200 201 /* 202 * returns 0 if we get a negative match for the hostname or the ip 203 * or if we get no match at all. returns -1 on error, or 1 on 204 * successful match. 205 */ 206 int 207 match_host_and_ip(const char *host, const char *ipaddr, 208 const char *patterns) 209 { 210 int mhost, mip; 211 212 if ((mip = addr_match_list(ipaddr, patterns)) == -2) 213 return -1; /* error in ipaddr match */ 214 else if (host == NULL || ipaddr == NULL || mip == -1) 215 return 0; /* negative ip address match, or testing pattern */ 216 217 /* negative hostname match */ 218 if ((mhost = match_hostname(host, patterns)) == -1) 219 return 0; 220 /* no match at all */ 221 if (mhost == 0 && mip == 0) 222 return 0; 223 return 1; 224 } 225 226 /* 227 * Match user, user@host_or_ip, user@host_or_ip_list against pattern. 228 * If user, host and ipaddr are all NULL then validate pattern/ 229 * Returns -1 on invalid pattern, 0 on no match, 1 on match. 230 */ 231 int 232 match_user(const char *user, const char *host, const char *ipaddr, 233 const char *pattern) 234 { 235 char *p, *pat; 236 int ret; 237 238 /* test mode */ 239 if (user == NULL && host == NULL && ipaddr == NULL) { 240 if ((p = strchr(pattern, '@')) != NULL && 241 match_host_and_ip(NULL, NULL, p + 1) < 0) 242 return -1; 243 return 0; 244 } 245 246 if ((p = strchr(pattern, '@')) == NULL) 247 return match_pattern(user, pattern); 248 249 pat = xstrdup(pattern); 250 p = strchr(pat, '@'); 251 *p++ = '\0'; 252 253 if ((ret = match_pattern(user, pat)) == 1) 254 ret = match_host_and_ip(host, ipaddr, p); 255 free(pat); 256 257 return ret; 258 } 259 260 /* 261 * Returns first item from client-list that is also supported by server-list, 262 * caller must free the returned string. 263 */ 264 #define MAX_PROP 40 265 #define SEP "," 266 char * 267 match_list(const char *client, const char *server, u_int *next) 268 { 269 char *sproposals[MAX_PROP]; 270 char *c, *s, *p, *ret, *cp, *sp; 271 int i, j, nproposals; 272 273 c = cp = xstrdup(client); 274 s = sp = xstrdup(server); 275 276 for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0'; 277 (p = strsep(&sp, SEP)), i++) { 278 if (i < MAX_PROP) 279 sproposals[i] = p; 280 else 281 break; 282 } 283 nproposals = i; 284 285 for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0'; 286 (p = strsep(&cp, SEP)), i++) { 287 for (j = 0; j < nproposals; j++) { 288 if (strcmp(p, sproposals[j]) == 0) { 289 ret = xstrdup(p); 290 if (next != NULL) 291 *next = (cp == NULL) ? 292 strlen(c) : (u_int)(cp - c); 293 free(c); 294 free(s); 295 return ret; 296 } 297 } 298 } 299 if (next != NULL) 300 *next = strlen(c); 301 free(c); 302 free(s); 303 return NULL; 304 } 305 306 /* 307 * Filter proposal using pattern-list filter. 308 * "blacklist" determines sense of filter: 309 * non-zero indicates that items matching filter should be excluded. 310 * zero indicates that only items matching filter should be included. 311 * returns NULL on allocation error, otherwise caller must free result. 312 */ 313 static char * 314 filter_list(const char *proposal, const char *filter, int blacklist) 315 { 316 size_t len = strlen(proposal) + 1; 317 char *fix_prop = malloc(len); 318 char *orig_prop = strdup(proposal); 319 char *cp, *tmp; 320 int r; 321 322 if (fix_prop == NULL || orig_prop == NULL) { 323 free(orig_prop); 324 free(fix_prop); 325 return NULL; 326 } 327 328 tmp = orig_prop; 329 *fix_prop = '\0'; 330 while ((cp = strsep(&tmp, ",")) != NULL) { 331 r = match_pattern_list(cp, filter, 0); 332 if ((blacklist && r != 1) || (!blacklist && r == 1)) { 333 if (*fix_prop != '\0') 334 strlcat(fix_prop, ",", len); 335 strlcat(fix_prop, cp, len); 336 } 337 } 338 free(orig_prop); 339 return fix_prop; 340 } 341 342 /* 343 * Filters a comma-separated list of strings, excluding any entry matching 344 * the 'filter' pattern list. Caller must free returned string. 345 */ 346 char * 347 match_filter_blacklist(const char *proposal, const char *filter) 348 { 349 return filter_list(proposal, filter, 1); 350 } 351 352 /* 353 * Filters a comma-separated list of strings, including only entries matching 354 * the 'filter' pattern list. Caller must free returned string. 355 */ 356 char * 357 match_filter_whitelist(const char *proposal, const char *filter) 358 { 359 return filter_list(proposal, filter, 0); 360 } 361