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1 | /* $OpenBSD: match.c,v 1.25 2006/07/22 20:48:23 stevesk Exp $ */ | |
2 | /* | |
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. | |
7 | * | |
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". | |
13 | */ | |
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 | */ | |
37 | ||
38 | #include "includes.h" | |
39 | ||
40 | #include <ctype.h> | |
41 | #include <string.h> | |
42 | ||
43 | #include "match.h" | |
44 | #include "xmalloc.h" | |
45 | ||
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 | */ | |
50 | ||
51 | int | |
52 | match_pattern(const char *s, const char *pattern) | |
53 | { | |
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 != '*') { | |
69 | /* | |
70 | * Look instances of the next character in | |
71 | * pattern, and try to match starting from | |
72 | * those. | |
73 | */ | |
74 | for (; *s; s++) | |
75 | if (*s == *pattern && | |
76 | match_pattern(s + 1, pattern + 1)) | |
77 | return 1; | |
78 | /* Failed. */ | |
79 | return 0; | |
80 | } | |
81 | /* | |
82 | * Move ahead one character at a time and try to | |
83 | * match at each position. | |
84 | */ | |
85 | for (; *s; s++) | |
86 | if (match_pattern(s, pattern)) | |
87 | return 1; | |
88 | /* Failed. */ | |
89 | return 0; | |
90 | } | |
91 | /* | |
92 | * There must be at least one more character in the string. | |
93 | * If we are at the end, fail. | |
94 | */ | |
95 | if (!*s) | |
96 | return 0; | |
97 | ||
98 | /* Check if the next character of the string is acceptable. */ | |
99 | if (*pattern != '?' && *pattern != *s) | |
100 | return 0; | |
101 | ||
102 | /* Move to the next character, both in string and in pattern. */ | |
103 | s++; | |
104 | pattern++; | |
105 | } | |
106 | /* NOTREACHED */ | |
107 | } | |
108 | ||
109 | /* | |
110 | * Tries to match the string against the | |
111 | * comma-separated sequence of subpatterns (each possibly preceded by ! to | |
112 | * indicate negation). Returns -1 if negation matches, 1 if there is | |
113 | * a positive match, 0 if there is no match at all. | |
114 | */ | |
115 | ||
116 | int | |
117 | match_pattern_list(const char *string, const char *pattern, u_int len, | |
118 | int dolower) | |
119 | { | |
120 | char sub[1024]; | |
121 | int negated; | |
122 | int got_positive; | |
123 | u_int i, subi; | |
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; | |
139 | i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; | |
140 | subi++, i++) | |
141 | sub[subi] = dolower && isupper(pattern[i]) ? | |
142 | (char)tolower(pattern[i]) : pattern[i]; | |
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 | ||
154 | /* Try to match the subpattern against the string. */ | |
155 | if (match_pattern(string, sub)) { | |
156 | if (negated) | |
157 | return -1; /* Negative */ | |
158 | else | |
159 | got_positive = 1; /* Positive */ | |
160 | } | |
161 | } | |
162 | ||
163 | /* | |
164 | * Return success if got a positive match. If there was a negative | |
165 | * match, we have already returned -1 and never get here. | |
166 | */ | |
167 | return got_positive; | |
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); | |
180 | } | |
181 | ||
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; | |
191 | ||
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; | |
202 | } | |
203 | ||
204 | /* | |
205 | * match user, user@host_or_ip, user@host_or_ip_list against pattern | |
206 | */ | |
207 | int | |
208 | match_user(const char *user, const char *host, const char *ipaddr, | |
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) | |
222 | ret = match_host_and_ip(host, ipaddr, p); | |
223 | xfree(pat); | |
224 | ||
225 | return ret; | |
226 | } | |
227 | ||
228 | /* | |
229 | * Returns first item from client-list that is also supported by server-list, | |
230 | * caller must xfree() returned string. | |
231 | */ | |
232 | #define MAX_PROP 40 | |
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'; | |
245 | (p = strsep(&sp, SEP)), i++) { | |
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'; | |
254 | (p = strsep(&cp, SEP)), i++) { | |
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) ? | |
260 | strlen(c) : (u_int)(cp - c); | |
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; | |
272 | } |