1 /* $NetBSD: match.c,v 1.7 2016/12/25 00:07:47 christos Exp $ */ 2 /* $OpenBSD: match.c,v 1.33 2016/11/06 05:46:37 djm Exp $ */ 3 4 /* 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 7 * All rights reserved 8 * Simple pattern matching, with '*' and '?' as wildcards. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 */ 16 /* 17 * Copyright (c) 2000 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include "includes.h" 41 __RCSID("$NetBSD: match.c,v 1.7 2016/12/25 00:07:47 christos Exp $"); 42 #include <sys/types.h> 43 44 #include <ctype.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 #include "xmalloc.h" 49 #include "match.h" 50 51 /* 52 * Returns true if the given string matches the pattern (which may contain ? 53 * and * as wildcards), and zero if it does not match. 54 */ 55 56 int 57 match_pattern(const char *s, const char *pattern) 58 { 59 for (;;) { 60 /* If at end of pattern, accept if also at end of string. */ 61 if (!*pattern) 62 return !*s; 63 64 if (*pattern == '*') { 65 /* Skip the asterisk. */ 66 pattern++; 67 68 /* If at end of pattern, accept immediately. */ 69 if (!*pattern) 70 return 1; 71 72 /* If next character in pattern is known, optimize. */ 73 if (*pattern != '?' && *pattern != '*') { 74 /* 75 * Look instances of the next character in 76 * pattern, and try to match starting from 77 * those. 78 */ 79 for (; *s; s++) 80 if (*s == *pattern && 81 match_pattern(s + 1, pattern + 1)) 82 return 1; 83 /* Failed. */ 84 return 0; 85 } 86 /* 87 * Move ahead one character at a time and try to 88 * match at each position. 89 */ 90 for (; *s; s++) 91 if (match_pattern(s, pattern)) 92 return 1; 93 /* Failed. */ 94 return 0; 95 } 96 /* 97 * There must be at least one more character in the string. 98 * If we are at the end, fail. 99 */ 100 if (!*s) 101 return 0; 102 103 /* Check if the next character of the string is acceptable. */ 104 if (*pattern != '?' && *pattern != *s) 105 return 0; 106 107 /* Move to the next character, both in string and in pattern. */ 108 s++; 109 pattern++; 110 } 111 /* NOTREACHED */ 112 } 113 114 /* 115 * Tries to match the string against the 116 * comma-separated sequence of subpatterns (each possibly preceded by ! to 117 * indicate negation). Returns -1 if negation matches, 1 if there is 118 * a positive match, 0 if there is no match at all. 119 */ 120 int 121 match_pattern_list(const char *string, const char *pattern, int dolower) 122 { 123 char sub[1024]; 124 int negated; 125 int got_positive; 126 u_int i, subi, len = strlen(pattern); 127 128 got_positive = 0; 129 for (i = 0; i < len;) { 130 /* Check if the subpattern is negated. */ 131 if (pattern[i] == '!') { 132 negated = 1; 133 i++; 134 } else 135 negated = 0; 136 137 /* 138 * Extract the subpattern up to a comma or end. Convert the 139 * subpattern to lowercase. 140 */ 141 for (subi = 0; 142 i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; 143 subi++, i++) 144 sub[subi] = dolower && isupper((u_char)pattern[i]) ? 145 tolower((u_char)pattern[i]) : pattern[i]; 146 /* If subpattern too long, return failure (no match). */ 147 if (subi >= sizeof(sub) - 1) 148 return 0; 149 150 /* If the subpattern was terminated by a comma, skip the comma. */ 151 if (i < len && pattern[i] == ',') 152 i++; 153 154 /* Null-terminate the subpattern. */ 155 sub[subi] = '\0'; 156 157 /* Try to match the subpattern against the string. */ 158 if (match_pattern(string, sub)) { 159 if (negated) 160 return -1; /* Negative */ 161 else 162 got_positive = 1; /* Positive */ 163 } 164 } 165 166 /* 167 * Return success if got a positive match. If there was a negative 168 * match, we have already returned -1 and never get here. 169 */ 170 return got_positive; 171 } 172 173 /* 174 * Tries to match the host name (which must be in all lowercase) against the 175 * comma-separated sequence of subpatterns (each possibly preceded by ! to 176 * indicate negation). Returns -1 if negation matches, 1 if there is 177 * a positive match, 0 if there is no match at all. 178 */ 179 int 180 match_hostname(const char *host, const char *pattern) 181 { 182 return match_pattern_list(host, pattern, 1); 183 } 184 185 /* 186 * returns 0 if we get a negative match for the hostname or the ip 187 * or if we get no match at all. returns -1 on error, or 1 on 188 * successful match. 189 */ 190 int 191 match_host_and_ip(const char *host, const char *ipaddr, 192 const char *patterns) 193 { 194 int mhost, mip; 195 196 if ((mip = addr_match_list(ipaddr, patterns)) == -2) 197 return -1; /* error in ipaddr match */ 198 else if (host == NULL || ipaddr == NULL || mip == -1) 199 return 0; /* negative ip address match, or testing pattern */ 200 201 /* negative hostname match */ 202 if ((mhost = match_hostname(host, patterns)) == -1) 203 return 0; 204 /* no match at all */ 205 if (mhost == 0 && mip == 0) 206 return 0; 207 return 1; 208 } 209 210 /* 211 * Match user, user@host_or_ip, user@host_or_ip_list against pattern. 212 * If user, host and ipaddr are all NULL then validate pattern/ 213 * Returns -1 on invalid pattern, 0 on no match, 1 on match. 214 */ 215 int 216 match_user(const char *user, const char *host, const char *ipaddr, 217 const char *pattern) 218 { 219 char *p, *pat; 220 int ret; 221 222 /* test mode */ 223 if (user == NULL && host == NULL && ipaddr == NULL) { 224 if ((p = strchr(pattern, '@')) != NULL && 225 match_host_and_ip(NULL, NULL, p + 1) < 0) 226 return -1; 227 return 0; 228 } 229 230 if ((p = strchr(pattern,'@')) == NULL) 231 return match_pattern(user, pattern); 232 233 pat = xstrdup(pattern); 234 p = strchr(pat, '@'); 235 *p++ = '\0'; 236 237 if ((ret = match_pattern(user, pat)) == 1) 238 ret = match_host_and_ip(host, ipaddr, p); 239 free(pat); 240 241 return ret; 242 } 243 244 /* 245 * Returns first item from client-list that is also supported by server-list, 246 * caller must free the returned string. 247 */ 248 #define MAX_PROP 40 249 #define SEP "," 250 char * 251 match_list(const char *client, const char *server, u_int *next) 252 { 253 char *sproposals[MAX_PROP]; 254 char *c, *s, *p, *ret, *cp, *sp; 255 int i, j, nproposals; 256 257 c = cp = xstrdup(client); 258 s = sp = xstrdup(server); 259 260 for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0'; 261 (p = strsep(&sp, SEP)), i++) { 262 if (i < MAX_PROP) 263 sproposals[i] = p; 264 else 265 break; 266 } 267 nproposals = i; 268 269 for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0'; 270 (p = strsep(&cp, SEP)), i++) { 271 for (j = 0; j < nproposals; j++) { 272 if (strcmp(p, sproposals[j]) == 0) { 273 ret = xstrdup(p); 274 if (next != NULL) 275 *next = (cp == NULL) ? 276 strlen(c) : (u_int)(cp - c); 277 free(c); 278 free(s); 279 return ret; 280 } 281 } 282 } 283 if (next != NULL) 284 *next = strlen(c); 285 free(c); 286 free(s); 287 return NULL; 288 } 289