Annotation of src/usr.bin/ssh/match.c, Revision 1.32
1.32 ! djm 1: /* $OpenBSD: match.c,v 1.31 2016/08/23 03:22:49 djm 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>
1.1 deraadt 43:
1.26 deraadt 44: #include "xmalloc.h"
1.11 markus 45: #include "match.h"
1.1 deraadt 46:
1.4 markus 47: /*
48: * Returns true if the given string matches the pattern (which may contain ?
49: * and * as wildcards), and zero if it does not match.
50: */
1.2 markus 51:
1.6 markus 52: int
1.2 markus 53: match_pattern(const char *s, const char *pattern)
1.1 deraadt 54: {
1.2 markus 55: for (;;) {
56: /* If at end of pattern, accept if also at end of string. */
57: if (!*pattern)
58: return !*s;
59:
60: if (*pattern == '*') {
61: /* Skip the asterisk. */
62: pattern++;
63:
64: /* If at end of pattern, accept immediately. */
65: if (!*pattern)
66: return 1;
67:
68: /* If next character in pattern is known, optimize. */
69: if (*pattern != '?' && *pattern != '*') {
1.4 markus 70: /*
71: * Look instances of the next character in
72: * pattern, and try to match starting from
73: * those.
74: */
1.2 markus 75: for (; *s; s++)
76: if (*s == *pattern &&
77: match_pattern(s + 1, pattern + 1))
78: return 1;
79: /* Failed. */
80: return 0;
81: }
1.4 markus 82: /*
83: * Move ahead one character at a time and try to
84: * match at each position.
85: */
1.2 markus 86: for (; *s; s++)
87: if (match_pattern(s, pattern))
88: return 1;
89: /* Failed. */
90: return 0;
91: }
1.4 markus 92: /*
93: * There must be at least one more character in the string.
94: * If we are at the end, fail.
95: */
1.2 markus 96: if (!*s)
97: return 0;
98:
1.4 markus 99: /* Check if the next character of the string is acceptable. */
1.2 markus 100: if (*pattern != '?' && *pattern != *s)
101: return 0;
102:
1.4 markus 103: /* Move to the next character, both in string and in pattern. */
1.2 markus 104: s++;
105: pattern++;
106: }
107: /* NOTREACHED */
1.5 markus 108: }
109:
110: /*
1.15 markus 111: * Tries to match the string against the
1.5 markus 112: * comma-separated sequence of subpatterns (each possibly preceded by ! to
1.7 markus 113: * indicate negation). Returns -1 if negation matches, 1 if there is
114: * a positive match, 0 if there is no match at all.
1.5 markus 115: */
116: int
1.30 djm 117: match_pattern_list(const char *string, const char *pattern, int dolower)
1.5 markus 118: {
119: char sub[1024];
120: int negated;
121: int got_positive;
1.30 djm 122: u_int i, subi, len = strlen(pattern);
1.5 markus 123:
124: got_positive = 0;
125: for (i = 0; i < len;) {
126: /* Check if the subpattern is negated. */
127: if (pattern[i] == '!') {
128: negated = 1;
129: i++;
130: } else
131: negated = 0;
132:
133: /*
134: * Extract the subpattern up to a comma or end. Convert the
135: * subpattern to lowercase.
136: */
137: for (subi = 0;
1.16 deraadt 138: i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
139: subi++, i++)
1.29 deraadt 140: sub[subi] = dolower && isupper((u_char)pattern[i]) ?
141: tolower((u_char)pattern[i]) : pattern[i];
1.5 markus 142: /* If subpattern too long, return failure (no match). */
143: if (subi >= sizeof(sub) - 1)
144: return 0;
145:
146: /* If the subpattern was terminated by a comma, skip the comma. */
147: if (i < len && pattern[i] == ',')
148: i++;
149:
150: /* Null-terminate the subpattern. */
151: sub[subi] = '\0';
152:
1.15 markus 153: /* Try to match the subpattern against the string. */
154: if (match_pattern(string, sub)) {
1.5 markus 155: if (negated)
1.7 markus 156: return -1; /* Negative */
1.5 markus 157: else
1.7 markus 158: got_positive = 1; /* Positive */
1.32 ! djm 159: }
1.5 markus 160: }
161:
162: /*
163: * Return success if got a positive match. If there was a negative
1.7 markus 164: * match, we have already returned -1 and never get here.
1.5 markus 165: */
166: return got_positive;
1.15 markus 167: }
168:
169: /*
170: * Tries to match the host name (which must be in all lowercase) against the
171: * comma-separated sequence of subpatterns (each possibly preceded by ! to
172: * indicate negation). Returns -1 if negation matches, 1 if there is
173: * a positive match, 0 if there is no match at all.
174: */
175: int
1.30 djm 176: match_hostname(const char *host, const char *pattern)
1.15 markus 177: {
1.30 djm 178: return match_pattern_list(host, pattern, 1);
1.12 markus 179: }
180:
1.13 markus 181: /*
182: * returns 0 if we get a negative match for the hostname or the ip
1.27 djm 183: * or if we get no match at all. returns -1 on error, or 1 on
184: * successful match.
1.13 markus 185: */
186: int
187: match_host_and_ip(const char *host, const char *ipaddr,
188: const char *patterns)
189: {
190: int mhost, mip;
1.12 markus 191:
1.27 djm 192: /* error in ipaddr match */
193: if ((mip = addr_match_list(ipaddr, patterns)) == -2)
194: return -1;
195: else if (mip == -1) /* negative ip address match */
1.13 markus 196: return 0;
1.27 djm 197:
1.13 markus 198: /* negative hostname match */
1.30 djm 199: if ((mhost = match_hostname(host, patterns)) == -1)
1.13 markus 200: return 0;
201: /* no match at all */
202: if (mhost == 0 && mip == 0)
203: return 0;
204: return 1;
1.14 markus 205: }
206:
207: /*
208: * match user, user@host_or_ip, user@host_or_ip_list against pattern
209: */
210: int
1.19 markus 211: match_user(const char *user, const char *host, const char *ipaddr,
1.14 markus 212: const char *pattern)
213: {
214: char *p, *pat;
215: int ret;
216:
217: if ((p = strchr(pattern,'@')) == NULL)
218: return match_pattern(user, pattern);
219:
220: pat = xstrdup(pattern);
221: p = strchr(pat, '@');
222: *p++ = '\0';
223:
224: if ((ret = match_pattern(user, pat)) == 1)
1.19 markus 225: ret = match_host_and_ip(host, ipaddr, p);
1.28 djm 226: free(pat);
1.14 markus 227:
228: return ret;
1.13 markus 229: }
230:
231: /*
232: * Returns first item from client-list that is also supported by server-list,
1.28 djm 233: * caller must free the returned string.
1.13 markus 234: */
1.17 markus 235: #define MAX_PROP 40
1.12 markus 236: #define SEP ","
237: char *
238: match_list(const char *client, const char *server, u_int *next)
239: {
240: char *sproposals[MAX_PROP];
241: char *c, *s, *p, *ret, *cp, *sp;
242: int i, j, nproposals;
243:
244: c = cp = xstrdup(client);
245: s = sp = xstrdup(server);
246:
247: for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
1.16 deraadt 248: (p = strsep(&sp, SEP)), i++) {
1.12 markus 249: if (i < MAX_PROP)
250: sproposals[i] = p;
251: else
252: break;
253: }
254: nproposals = i;
255:
256: for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
1.16 deraadt 257: (p = strsep(&cp, SEP)), i++) {
1.12 markus 258: for (j = 0; j < nproposals; j++) {
259: if (strcmp(p, sproposals[j]) == 0) {
260: ret = xstrdup(p);
261: if (next != NULL)
262: *next = (cp == NULL) ?
1.20 djm 263: strlen(c) : (u_int)(cp - c);
1.28 djm 264: free(c);
265: free(s);
1.12 markus 266: return ret;
267: }
268: }
269: }
270: if (next != NULL)
271: *next = strlen(c);
1.28 djm 272: free(c);
273: free(s);
1.12 markus 274: return NULL;
1.1 deraadt 275: }
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