Annotation of src/usr.bin/ssh/match.c, Revision 1.14
1.1 deraadt 1: /*
1.3 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
5: * Simple pattern matching, with '*' and '?' as wildcards.
1.6 markus 6: *
1.9 deraadt 7: * As far as I am concerned, the code I have written for this software
8: * can be used freely for any purpose. Any derived versions of this
9: * software must be clearly marked as such, and if the derived work is
10: * incompatible with the protocol description in the RFC file, it must be
11: * called by a name other than "ssh" or "Secure Shell".
1.3 deraadt 12: */
1.12 markus 13: /*
14: * Copyright (c) 2000 Markus Friedl. All rights reserved.
15: *
16: * Redistribution and use in source and binary forms, with or without
17: * modification, are permitted provided that the following conditions
18: * are met:
19: * 1. Redistributions of source code must retain the above copyright
20: * notice, this list of conditions and the following disclaimer.
21: * 2. Redistributions in binary form must reproduce the above copyright
22: * notice, this list of conditions and the following disclaimer in the
23: * documentation and/or other materials provided with the distribution.
24: *
25: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35: */
1.1 deraadt 36:
37: #include "includes.h"
1.14 ! markus 38: RCSID("$OpenBSD: match.c,v 1.13 2001/06/24 05:25:10 markus Exp $");
1.1 deraadt 39:
1.11 markus 40: #include "match.h"
1.12 markus 41: #include "xmalloc.h"
1.1 deraadt 42:
1.4 markus 43: /*
44: * Returns true if the given string matches the pattern (which may contain ?
45: * and * as wildcards), and zero if it does not match.
46: */
1.2 markus 47:
1.6 markus 48: int
1.2 markus 49: match_pattern(const char *s, const char *pattern)
1.1 deraadt 50: {
1.2 markus 51: for (;;) {
52: /* If at end of pattern, accept if also at end of string. */
53: if (!*pattern)
54: return !*s;
55:
56: if (*pattern == '*') {
57: /* Skip the asterisk. */
58: pattern++;
59:
60: /* If at end of pattern, accept immediately. */
61: if (!*pattern)
62: return 1;
63:
64: /* If next character in pattern is known, optimize. */
65: if (*pattern != '?' && *pattern != '*') {
1.4 markus 66: /*
67: * Look instances of the next character in
68: * pattern, and try to match starting from
69: * those.
70: */
1.2 markus 71: for (; *s; s++)
72: if (*s == *pattern &&
73: match_pattern(s + 1, pattern + 1))
74: return 1;
75: /* Failed. */
76: return 0;
77: }
1.4 markus 78: /*
79: * Move ahead one character at a time and try to
80: * match at each position.
81: */
1.2 markus 82: for (; *s; s++)
83: if (match_pattern(s, pattern))
84: return 1;
85: /* Failed. */
86: return 0;
87: }
1.4 markus 88: /*
89: * There must be at least one more character in the string.
90: * If we are at the end, fail.
91: */
1.2 markus 92: if (!*s)
93: return 0;
94:
1.4 markus 95: /* Check if the next character of the string is acceptable. */
1.2 markus 96: if (*pattern != '?' && *pattern != *s)
97: return 0;
98:
1.4 markus 99: /* Move to the next character, both in string and in pattern. */
1.2 markus 100: s++;
101: pattern++;
102: }
103: /* NOTREACHED */
1.5 markus 104: }
105:
106: /*
107: * Tries to match the host name (which must be in all lowercase) against the
108: * comma-separated sequence of subpatterns (each possibly preceded by ! to
1.7 markus 109: * indicate negation). Returns -1 if negation matches, 1 if there is
110: * a positive match, 0 if there is no match at all.
1.5 markus 111: */
112:
113: int
1.10 markus 114: match_hostname(const char *host, const char *pattern, u_int len)
1.5 markus 115: {
116: char sub[1024];
117: int negated;
118: int got_positive;
1.10 markus 119: u_int i, subi;
1.5 markus 120:
121: got_positive = 0;
122: for (i = 0; i < len;) {
123: /* Check if the subpattern is negated. */
124: if (pattern[i] == '!') {
125: negated = 1;
126: i++;
127: } else
128: negated = 0;
129:
130: /*
131: * Extract the subpattern up to a comma or end. Convert the
132: * subpattern to lowercase.
133: */
134: for (subi = 0;
135: i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
136: subi++, i++)
137: sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i];
138: /* If subpattern too long, return failure (no match). */
139: if (subi >= sizeof(sub) - 1)
140: return 0;
141:
142: /* If the subpattern was terminated by a comma, skip the comma. */
143: if (i < len && pattern[i] == ',')
144: i++;
145:
146: /* Null-terminate the subpattern. */
147: sub[subi] = '\0';
148:
149: /* Try to match the subpattern against the host name. */
150: if (match_pattern(host, sub)) {
151: if (negated)
1.7 markus 152: return -1; /* Negative */
1.5 markus 153: else
1.7 markus 154: got_positive = 1; /* Positive */
1.5 markus 155: }
156: }
157:
158: /*
159: * Return success if got a positive match. If there was a negative
1.7 markus 160: * match, we have already returned -1 and never get here.
1.5 markus 161: */
162: return got_positive;
1.12 markus 163: }
164:
1.13 markus 165: /*
166: * returns 0 if we get a negative match for the hostname or the ip
167: * or if we get no match at all. returns 1 otherwise.
168: */
169: int
170: match_host_and_ip(const char *host, const char *ipaddr,
171: const char *patterns)
172: {
173: int mhost, mip;
1.12 markus 174:
1.13 markus 175: /* negative ipaddr match */
176: if ((mip = match_hostname(ipaddr, patterns, strlen(patterns))) == -1)
177: return 0;
178: /* negative hostname match */
179: if ((mhost = match_hostname(host, patterns, strlen(patterns))) == -1)
180: return 0;
181: /* no match at all */
182: if (mhost == 0 && mip == 0)
183: return 0;
184: return 1;
1.14 ! markus 185: }
! 186:
! 187: /*
! 188: * match user, user@host_or_ip, user@host_or_ip_list against pattern
! 189: */
! 190: int
! 191: match_user(const char *user, const char *host, const char *ipaddr,
! 192: const char *pattern)
! 193: {
! 194: char *p, *pat;
! 195: int ret;
! 196:
! 197: if ((p = strchr(pattern,'@')) == NULL)
! 198: return match_pattern(user, pattern);
! 199:
! 200: pat = xstrdup(pattern);
! 201: p = strchr(pat, '@');
! 202: *p++ = '\0';
! 203:
! 204: if ((ret = match_pattern(user, pat)) == 1)
! 205: ret = match_host_and_ip(host, ipaddr, p);
! 206: xfree(pat);
! 207:
! 208: return ret;
1.13 markus 209: }
210:
211: /*
212: * Returns first item from client-list that is also supported by server-list,
213: * caller must xfree() returned string.
214: */
1.12 markus 215: #define MAX_PROP 20
216: #define SEP ","
217: char *
218: match_list(const char *client, const char *server, u_int *next)
219: {
220: char *sproposals[MAX_PROP];
221: char *c, *s, *p, *ret, *cp, *sp;
222: int i, j, nproposals;
223:
224: c = cp = xstrdup(client);
225: s = sp = xstrdup(server);
226:
227: for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
228: (p = strsep(&sp, SEP)), i++) {
229: if (i < MAX_PROP)
230: sproposals[i] = p;
231: else
232: break;
233: }
234: nproposals = i;
235:
236: for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
237: (p = strsep(&cp, SEP)), i++) {
238: for (j = 0; j < nproposals; j++) {
239: if (strcmp(p, sproposals[j]) == 0) {
240: ret = xstrdup(p);
241: if (next != NULL)
242: *next = (cp == NULL) ?
243: strlen(c) : cp - c;
244: xfree(c);
245: xfree(s);
246: return ret;
247: }
248: }
249: }
250: if (next != NULL)
251: *next = strlen(c);
252: xfree(c);
253: xfree(s);
254: return NULL;
1.1 deraadt 255: }