Annotation of src/usr.bin/ssh/match.c, Revision 1.40
1.40 ! djm 1: /* $OpenBSD: match.c,v 1.39 2019/03/06 22:14:23 dtucker Exp $ */
1.1 deraadt 2: /*
1.3 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
6: * Simple pattern matching, with '*' and '?' as wildcards.
1.6 markus 7: *
1.9 deraadt 8: * As far as I am concerned, the code I have written for this software
9: * can be used freely for any purpose. Any derived versions of this
10: * software must be clearly marked as such, and if the derived work is
11: * incompatible with the protocol description in the RFC file, it must be
12: * called by a name other than "ssh" or "Secure Shell".
1.3 deraadt 13: */
1.12 markus 14: /*
15: * Copyright (c) 2000 Markus Friedl. All rights reserved.
16: *
17: * Redistribution and use in source and binary forms, with or without
18: * modification, are permitted provided that the following conditions
19: * are met:
20: * 1. Redistributions of source code must retain the above copyright
21: * notice, this list of conditions and the following disclaimer.
22: * 2. Redistributions in binary form must reproduce the above copyright
23: * notice, this list of conditions and the following disclaimer in the
24: * documentation and/or other materials provided with the distribution.
25: *
26: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36: */
1.1 deraadt 37:
1.26 deraadt 38: #include <sys/types.h>
1.21 stevesk 39:
40: #include <ctype.h>
1.28 djm 41: #include <stdlib.h>
1.25 stevesk 42: #include <string.h>
1.37 djm 43: #include <stdio.h>
1.1 deraadt 44:
1.26 deraadt 45: #include "xmalloc.h"
1.11 markus 46: #include "match.h"
1.37 djm 47: #include "misc.h"
1.1 deraadt 48:
1.4 markus 49: /*
50: * Returns true if the given string matches the pattern (which may contain ?
51: * and * as wildcards), and zero if it does not match.
52: */
1.2 markus 53:
1.6 markus 54: int
1.2 markus 55: match_pattern(const char *s, const char *pattern)
1.1 deraadt 56: {
1.2 markus 57: for (;;) {
58: /* If at end of pattern, accept if also at end of string. */
59: if (!*pattern)
60: return !*s;
61:
62: if (*pattern == '*') {
63: /* Skip the asterisk. */
64: pattern++;
65:
66: /* If at end of pattern, accept immediately. */
67: if (!*pattern)
68: return 1;
69:
70: /* If next character in pattern is known, optimize. */
71: if (*pattern != '?' && *pattern != '*') {
1.4 markus 72: /*
73: * Look instances of the next character in
74: * pattern, and try to match starting from
75: * those.
76: */
1.2 markus 77: for (; *s; s++)
78: if (*s == *pattern &&
79: match_pattern(s + 1, pattern + 1))
80: return 1;
81: /* Failed. */
82: return 0;
83: }
1.4 markus 84: /*
85: * Move ahead one character at a time and try to
86: * match at each position.
87: */
1.2 markus 88: for (; *s; s++)
89: if (match_pattern(s, pattern))
90: return 1;
91: /* Failed. */
92: return 0;
93: }
1.4 markus 94: /*
95: * There must be at least one more character in the string.
96: * If we are at the end, fail.
97: */
1.2 markus 98: if (!*s)
99: return 0;
100:
1.4 markus 101: /* Check if the next character of the string is acceptable. */
1.2 markus 102: if (*pattern != '?' && *pattern != *s)
103: return 0;
104:
1.4 markus 105: /* Move to the next character, both in string and in pattern. */
1.2 markus 106: s++;
107: pattern++;
108: }
109: /* NOTREACHED */
1.5 markus 110: }
111:
112: /*
1.15 markus 113: * Tries to match the string against the
1.5 markus 114: * comma-separated sequence of subpatterns (each possibly preceded by ! to
1.7 markus 115: * indicate negation). Returns -1 if negation matches, 1 if there is
116: * a positive match, 0 if there is no match at all.
1.5 markus 117: */
118: int
1.30 djm 119: match_pattern_list(const char *string, const char *pattern, int dolower)
1.5 markus 120: {
121: char sub[1024];
122: int negated;
123: int got_positive;
1.30 djm 124: u_int i, subi, len = strlen(pattern);
1.5 markus 125:
126: got_positive = 0;
127: for (i = 0; i < len;) {
128: /* Check if the subpattern is negated. */
129: if (pattern[i] == '!') {
130: negated = 1;
131: i++;
132: } else
133: negated = 0;
134:
135: /*
136: * Extract the subpattern up to a comma or end. Convert the
137: * subpattern to lowercase.
138: */
139: for (subi = 0;
1.16 deraadt 140: i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
141: subi++, i++)
1.29 deraadt 142: sub[subi] = dolower && isupper((u_char)pattern[i]) ?
143: tolower((u_char)pattern[i]) : pattern[i];
1.5 markus 144: /* If subpattern too long, return failure (no match). */
145: if (subi >= sizeof(sub) - 1)
146: return 0;
147:
1.36 djm 148: /* If the subpattern was terminated by a comma, then skip it. */
1.5 markus 149: if (i < len && pattern[i] == ',')
150: i++;
151:
152: /* Null-terminate the subpattern. */
153: sub[subi] = '\0';
154:
1.15 markus 155: /* Try to match the subpattern against the string. */
156: if (match_pattern(string, sub)) {
1.5 markus 157: if (negated)
1.7 markus 158: return -1; /* Negative */
1.5 markus 159: else
1.7 markus 160: got_positive = 1; /* Positive */
1.32 djm 161: }
1.5 markus 162: }
163:
164: /*
165: * Return success if got a positive match. If there was a negative
1.7 markus 166: * match, we have already returned -1 and never get here.
1.5 markus 167: */
168: return got_positive;
1.39 dtucker 169: }
170:
171: /* Match a list representing users or groups. */
172: int
173: match_usergroup_pattern_list(const char *string, const char *pattern)
174: {
175: /* Case sensitive match */
176: return match_pattern_list(string, pattern, 0);
1.15 markus 177: }
178:
179: /*
180: * Tries to match the host name (which must be in all lowercase) against the
181: * comma-separated sequence of subpatterns (each possibly preceded by ! to
182: * indicate negation). Returns -1 if negation matches, 1 if there is
183: * a positive match, 0 if there is no match at all.
184: */
185: int
1.30 djm 186: match_hostname(const char *host, const char *pattern)
1.15 markus 187: {
1.37 djm 188: char *hostcopy = xstrdup(host);
189: int r;
190:
191: lowercase(hostcopy);
192: r = match_pattern_list(hostcopy, pattern, 1);
193: free(hostcopy);
194: return r;
1.12 markus 195: }
196:
1.13 markus 197: /*
198: * returns 0 if we get a negative match for the hostname or the ip
1.27 djm 199: * or if we get no match at all. returns -1 on error, or 1 on
200: * successful match.
1.13 markus 201: */
202: int
203: match_host_and_ip(const char *host, const char *ipaddr,
204: const char *patterns)
205: {
206: int mhost, mip;
1.12 markus 207:
1.27 djm 208: if ((mip = addr_match_list(ipaddr, patterns)) == -2)
1.33 djm 209: return -1; /* error in ipaddr match */
210: else if (host == NULL || ipaddr == NULL || mip == -1)
211: return 0; /* negative ip address match, or testing pattern */
1.27 djm 212:
1.13 markus 213: /* negative hostname match */
1.30 djm 214: if ((mhost = match_hostname(host, patterns)) == -1)
1.13 markus 215: return 0;
216: /* no match at all */
217: if (mhost == 0 && mip == 0)
218: return 0;
219: return 1;
1.14 markus 220: }
221:
222: /*
1.33 djm 223: * Match user, user@host_or_ip, user@host_or_ip_list against pattern.
224: * If user, host and ipaddr are all NULL then validate pattern/
225: * Returns -1 on invalid pattern, 0 on no match, 1 on match.
1.14 markus 226: */
227: int
1.19 markus 228: match_user(const char *user, const char *host, const char *ipaddr,
1.14 markus 229: const char *pattern)
230: {
231: char *p, *pat;
232: int ret;
1.33 djm 233:
234: /* test mode */
235: if (user == NULL && host == NULL && ipaddr == NULL) {
236: if ((p = strchr(pattern, '@')) != NULL &&
237: match_host_and_ip(NULL, NULL, p + 1) < 0)
238: return -1;
239: return 0;
240: }
1.14 markus 241:
1.40 ! djm 242: if ((p = strchr(pattern, '@')) == NULL)
1.14 markus 243: return match_pattern(user, pattern);
244:
245: pat = xstrdup(pattern);
246: p = strchr(pat, '@');
247: *p++ = '\0';
248:
249: if ((ret = match_pattern(user, pat)) == 1)
1.19 markus 250: ret = match_host_and_ip(host, ipaddr, p);
1.28 djm 251: free(pat);
1.14 markus 252:
253: return ret;
1.13 markus 254: }
255:
256: /*
257: * Returns first item from client-list that is also supported by server-list,
1.28 djm 258: * caller must free the returned string.
1.13 markus 259: */
1.17 markus 260: #define MAX_PROP 40
1.12 markus 261: #define SEP ","
262: char *
263: match_list(const char *client, const char *server, u_int *next)
264: {
265: char *sproposals[MAX_PROP];
266: char *c, *s, *p, *ret, *cp, *sp;
267: int i, j, nproposals;
268:
269: c = cp = xstrdup(client);
270: s = sp = xstrdup(server);
271:
272: for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
1.16 deraadt 273: (p = strsep(&sp, SEP)), i++) {
1.12 markus 274: if (i < MAX_PROP)
275: sproposals[i] = p;
276: else
277: break;
278: }
279: nproposals = i;
280:
281: for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
1.16 deraadt 282: (p = strsep(&cp, SEP)), i++) {
1.12 markus 283: for (j = 0; j < nproposals; j++) {
284: if (strcmp(p, sproposals[j]) == 0) {
285: ret = xstrdup(p);
286: if (next != NULL)
287: *next = (cp == NULL) ?
1.20 djm 288: strlen(c) : (u_int)(cp - c);
1.28 djm 289: free(c);
290: free(s);
1.12 markus 291: return ret;
292: }
293: }
294: }
295: if (next != NULL)
296: *next = strlen(c);
1.28 djm 297: free(c);
298: free(s);
1.12 markus 299: return NULL;
1.1 deraadt 300: }
1.34 djm 301:
302: /*
1.38 djm 303: * Filter proposal using pattern-list filter.
304: * "blacklist" determines sense of filter:
305: * non-zero indicates that items matching filter should be excluded.
306: * zero indicates that only items matching filter should be included.
307: * returns NULL on allocation error, otherwise caller must free result.
1.34 djm 308: */
1.38 djm 309: static char *
310: filter_list(const char *proposal, const char *filter, int blacklist)
1.34 djm 311: {
312: size_t len = strlen(proposal) + 1;
313: char *fix_prop = malloc(len);
314: char *orig_prop = strdup(proposal);
315: char *cp, *tmp;
1.38 djm 316: int r;
1.34 djm 317:
1.35 jsg 318: if (fix_prop == NULL || orig_prop == NULL) {
319: free(orig_prop);
320: free(fix_prop);
1.34 djm 321: return NULL;
1.35 jsg 322: }
1.34 djm 323:
324: tmp = orig_prop;
325: *fix_prop = '\0';
326: while ((cp = strsep(&tmp, ",")) != NULL) {
1.38 djm 327: r = match_pattern_list(cp, filter, 0);
328: if ((blacklist && r != 1) || (!blacklist && r == 1)) {
1.34 djm 329: if (*fix_prop != '\0')
330: strlcat(fix_prop, ",", len);
331: strlcat(fix_prop, cp, len);
332: }
333: }
334: free(orig_prop);
335: return fix_prop;
336: }
337:
1.38 djm 338: /*
339: * Filters a comma-separated list of strings, excluding any entry matching
340: * the 'filter' pattern list. Caller must free returned string.
341: */
342: char *
343: match_filter_blacklist(const char *proposal, const char *filter)
344: {
345: return filter_list(proposal, filter, 1);
346: }
347:
348: /*
349: * Filters a comma-separated list of strings, including only entries matching
350: * the 'filter' pattern list. Caller must free returned string.
351: */
352: char *
353: match_filter_whitelist(const char *proposal, const char *filter)
354: {
355: return filter_list(proposal, filter, 0);
356: }
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