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1 | /* | |
2 | * | |
3 | * match.c | |
4 | * | |
5 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | * | |
7 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | * All rights reserved | |
9 | * | |
10 | * Created: Thu Jun 22 01:17:50 1995 ylo | |
11 | * | |
12 | * Simple pattern matching, with '*' and '?' as wildcards. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include "includes.h" | |
17 | RCSID("$OpenBSD: match.c,v 1.8 2000/06/20 01:39:42 markus Exp $"); | |
18 | ||
19 | #include "ssh.h" | |
20 | ||
21 | /* | |
22 | * Returns true if the given string matches the pattern (which may contain ? | |
23 | * and * as wildcards), and zero if it does not match. | |
24 | */ | |
25 | ||
26 | int | |
27 | match_pattern(const char *s, const char *pattern) | |
28 | { | |
29 | for (;;) { | |
30 | /* If at end of pattern, accept if also at end of string. */ | |
31 | if (!*pattern) | |
32 | return !*s; | |
33 | ||
34 | if (*pattern == '*') { | |
35 | /* Skip the asterisk. */ | |
36 | pattern++; | |
37 | ||
38 | /* If at end of pattern, accept immediately. */ | |
39 | if (!*pattern) | |
40 | return 1; | |
41 | ||
42 | /* If next character in pattern is known, optimize. */ | |
43 | if (*pattern != '?' && *pattern != '*') { | |
44 | /* | |
45 | * Look instances of the next character in | |
46 | * pattern, and try to match starting from | |
47 | * those. | |
48 | */ | |
49 | for (; *s; s++) | |
50 | if (*s == *pattern && | |
51 | match_pattern(s + 1, pattern + 1)) | |
52 | return 1; | |
53 | /* Failed. */ | |
54 | return 0; | |
55 | } | |
56 | /* | |
57 | * Move ahead one character at a time and try to | |
58 | * match at each position. | |
59 | */ | |
60 | for (; *s; s++) | |
61 | if (match_pattern(s, pattern)) | |
62 | return 1; | |
63 | /* Failed. */ | |
64 | return 0; | |
65 | } | |
66 | /* | |
67 | * There must be at least one more character in the string. | |
68 | * If we are at the end, fail. | |
69 | */ | |
70 | if (!*s) | |
71 | return 0; | |
72 | ||
73 | /* Check if the next character of the string is acceptable. */ | |
74 | if (*pattern != '?' && *pattern != *s) | |
75 | return 0; | |
76 | ||
77 | /* Move to the next character, both in string and in pattern. */ | |
78 | s++; | |
79 | pattern++; | |
80 | } | |
81 | /* NOTREACHED */ | |
82 | } | |
83 | ||
84 | /* | |
85 | * Tries to match the host name (which must be in all lowercase) against the | |
86 | * comma-separated sequence of subpatterns (each possibly preceded by ! to | |
87 | * indicate negation). Returns -1 if negation matches, 1 if there is | |
88 | * a positive match, 0 if there is no match at all. | |
89 | */ | |
90 | ||
91 | int | |
92 | match_hostname(const char *host, const char *pattern, unsigned int len) | |
93 | { | |
94 | char sub[1024]; | |
95 | int negated; | |
96 | int got_positive; | |
97 | unsigned int i, subi; | |
98 | ||
99 | got_positive = 0; | |
100 | for (i = 0; i < len;) { | |
101 | /* Check if the subpattern is negated. */ | |
102 | if (pattern[i] == '!') { | |
103 | negated = 1; | |
104 | i++; | |
105 | } else | |
106 | negated = 0; | |
107 | ||
108 | /* | |
109 | * Extract the subpattern up to a comma or end. Convert the | |
110 | * subpattern to lowercase. | |
111 | */ | |
112 | for (subi = 0; | |
113 | i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; | |
114 | subi++, i++) | |
115 | sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i]; | |
116 | /* If subpattern too long, return failure (no match). */ | |
117 | if (subi >= sizeof(sub) - 1) | |
118 | return 0; | |
119 | ||
120 | /* If the subpattern was terminated by a comma, skip the comma. */ | |
121 | if (i < len && pattern[i] == ',') | |
122 | i++; | |
123 | ||
124 | /* Null-terminate the subpattern. */ | |
125 | sub[subi] = '\0'; | |
126 | ||
127 | /* Try to match the subpattern against the host name. */ | |
128 | if (match_pattern(host, sub)) { | |
129 | if (negated) | |
130 | return -1; /* Negative */ | |
131 | else | |
132 | got_positive = 1; /* Positive */ | |
133 | } | |
134 | } | |
135 | ||
136 | /* | |
137 | * Return success if got a positive match. If there was a negative | |
138 | * match, we have already returned -1 and never get here. | |
139 | */ | |
140 | return got_positive; | |
141 | } |