Annotation of src/usr.bin/ssh/match.c, Revision 1.26
1.26 ! deraadt 1: /* $OpenBSD: match.c,v 1.25 2006/07/22 20:48:23 stevesk 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>
1.25 stevesk 41: #include <string.h>
1.1 deraadt 42:
1.26 ! deraadt 43: #include "xmalloc.h"
1.11 markus 44: #include "match.h"
1.1 deraadt 45:
1.4 markus 46: /*
47: * Returns true if the given string matches the pattern (which may contain ?
48: * and * as wildcards), and zero if it does not match.
49: */
1.2 markus 50:
1.6 markus 51: int
1.2 markus 52: match_pattern(const char *s, const char *pattern)
1.1 deraadt 53: {
1.2 markus 54: for (;;) {
55: /* If at end of pattern, accept if also at end of string. */
56: if (!*pattern)
57: return !*s;
58:
59: if (*pattern == '*') {
60: /* Skip the asterisk. */
61: pattern++;
62:
63: /* If at end of pattern, accept immediately. */
64: if (!*pattern)
65: return 1;
66:
67: /* If next character in pattern is known, optimize. */
68: if (*pattern != '?' && *pattern != '*') {
1.4 markus 69: /*
70: * Look instances of the next character in
71: * pattern, and try to match starting from
72: * those.
73: */
1.2 markus 74: for (; *s; s++)
75: if (*s == *pattern &&
76: match_pattern(s + 1, pattern + 1))
77: return 1;
78: /* Failed. */
79: return 0;
80: }
1.4 markus 81: /*
82: * Move ahead one character at a time and try to
83: * match at each position.
84: */
1.2 markus 85: for (; *s; s++)
86: if (match_pattern(s, pattern))
87: return 1;
88: /* Failed. */
89: return 0;
90: }
1.4 markus 91: /*
92: * There must be at least one more character in the string.
93: * If we are at the end, fail.
94: */
1.2 markus 95: if (!*s)
96: return 0;
97:
1.4 markus 98: /* Check if the next character of the string is acceptable. */
1.2 markus 99: if (*pattern != '?' && *pattern != *s)
100: return 0;
101:
1.4 markus 102: /* Move to the next character, both in string and in pattern. */
1.2 markus 103: s++;
104: pattern++;
105: }
106: /* NOTREACHED */
1.5 markus 107: }
108:
109: /*
1.15 markus 110: * Tries to match the string against the
1.5 markus 111: * comma-separated sequence of subpatterns (each possibly preceded by ! to
1.7 markus 112: * indicate negation). Returns -1 if negation matches, 1 if there is
113: * a positive match, 0 if there is no match at all.
1.5 markus 114: */
115:
116: int
1.15 markus 117: match_pattern_list(const char *string, const char *pattern, u_int len,
118: int dolower)
1.5 markus 119: {
120: char sub[1024];
121: int negated;
122: int got_positive;
1.10 markus 123: u_int i, subi;
1.5 markus 124:
125: got_positive = 0;
126: for (i = 0; i < len;) {
127: /* Check if the subpattern is negated. */
128: if (pattern[i] == '!') {
129: negated = 1;
130: i++;
131: } else
132: negated = 0;
133:
134: /*
135: * Extract the subpattern up to a comma or end. Convert the
136: * subpattern to lowercase.
137: */
138: for (subi = 0;
1.16 deraadt 139: i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
140: subi++, i++)
1.15 markus 141: sub[subi] = dolower && isupper(pattern[i]) ?
1.23 deraadt 142: (char)tolower(pattern[i]) : pattern[i];
1.5 markus 143: /* If subpattern too long, return failure (no match). */
144: if (subi >= sizeof(sub) - 1)
145: return 0;
146:
147: /* If the subpattern was terminated by a comma, skip the comma. */
148: if (i < len && pattern[i] == ',')
149: i++;
150:
151: /* Null-terminate the subpattern. */
152: sub[subi] = '\0';
153:
1.15 markus 154: /* Try to match the subpattern against the string. */
155: if (match_pattern(string, sub)) {
1.5 markus 156: if (negated)
1.7 markus 157: return -1; /* Negative */
1.5 markus 158: else
1.7 markus 159: got_positive = 1; /* Positive */
1.5 markus 160: }
161: }
162:
163: /*
164: * Return success if got a positive match. If there was a negative
1.7 markus 165: * match, we have already returned -1 and never get here.
1.5 markus 166: */
167: return got_positive;
1.15 markus 168: }
169:
170: /*
171: * Tries to match the host name (which must be in all lowercase) against the
172: * comma-separated sequence of subpatterns (each possibly preceded by ! to
173: * indicate negation). Returns -1 if negation matches, 1 if there is
174: * a positive match, 0 if there is no match at all.
175: */
176: int
177: match_hostname(const char *host, const char *pattern, u_int len)
178: {
179: return match_pattern_list(host, pattern, len, 1);
1.12 markus 180: }
181:
1.13 markus 182: /*
183: * returns 0 if we get a negative match for the hostname or the ip
184: * or if we get no match at all. returns 1 otherwise.
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:
1.13 markus 192: /* negative ipaddr match */
193: if ((mip = match_hostname(ipaddr, patterns, strlen(patterns))) == -1)
194: return 0;
195: /* negative hostname match */
196: if ((mhost = match_hostname(host, patterns, strlen(patterns))) == -1)
197: return 0;
198: /* no match at all */
199: if (mhost == 0 && mip == 0)
200: return 0;
201: return 1;
1.14 markus 202: }
203:
204: /*
205: * match user, user@host_or_ip, user@host_or_ip_list against pattern
206: */
207: int
1.19 markus 208: match_user(const char *user, const char *host, const char *ipaddr,
1.14 markus 209: const char *pattern)
210: {
211: char *p, *pat;
212: int ret;
213:
214: if ((p = strchr(pattern,'@')) == NULL)
215: return match_pattern(user, pattern);
216:
217: pat = xstrdup(pattern);
218: p = strchr(pat, '@');
219: *p++ = '\0';
220:
221: if ((ret = match_pattern(user, pat)) == 1)
1.19 markus 222: ret = match_host_and_ip(host, ipaddr, p);
1.14 markus 223: xfree(pat);
224:
225: return ret;
1.13 markus 226: }
227:
228: /*
229: * Returns first item from client-list that is also supported by server-list,
230: * caller must xfree() returned string.
231: */
1.17 markus 232: #define MAX_PROP 40
1.12 markus 233: #define SEP ","
234: char *
235: match_list(const char *client, const char *server, u_int *next)
236: {
237: char *sproposals[MAX_PROP];
238: char *c, *s, *p, *ret, *cp, *sp;
239: int i, j, nproposals;
240:
241: c = cp = xstrdup(client);
242: s = sp = xstrdup(server);
243:
244: for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
1.16 deraadt 245: (p = strsep(&sp, SEP)), i++) {
1.12 markus 246: if (i < MAX_PROP)
247: sproposals[i] = p;
248: else
249: break;
250: }
251: nproposals = i;
252:
253: for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
1.16 deraadt 254: (p = strsep(&cp, SEP)), i++) {
1.12 markus 255: for (j = 0; j < nproposals; j++) {
256: if (strcmp(p, sproposals[j]) == 0) {
257: ret = xstrdup(p);
258: if (next != NULL)
259: *next = (cp == NULL) ?
1.20 djm 260: strlen(c) : (u_int)(cp - c);
1.12 markus 261: xfree(c);
262: xfree(s);
263: return ret;
264: }
265: }
266: }
267: if (next != NULL)
268: *next = strlen(c);
269: xfree(c);
270: xfree(s);
271: return NULL;
1.1 deraadt 272: }