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1 | /* | |
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. | |
6 | * | |
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". | |
12 | */ | |
13 | ||
14 | #include "includes.h" | |
15 | RCSID("$OpenBSD: match.c,v 1.10 2000/12/19 23:17:57 markus Exp $"); | |
16 | ||
17 | #include "ssh.h" | |
18 | ||
19 | /* | |
20 | * Returns true if the given string matches the pattern (which may contain ? | |
21 | * and * as wildcards), and zero if it does not match. | |
22 | */ | |
23 | ||
24 | int | |
25 | match_pattern(const char *s, const char *pattern) | |
26 | { | |
27 | for (;;) { | |
28 | /* If at end of pattern, accept if also at end of string. */ | |
29 | if (!*pattern) | |
30 | return !*s; | |
31 | ||
32 | if (*pattern == '*') { | |
33 | /* Skip the asterisk. */ | |
34 | pattern++; | |
35 | ||
36 | /* If at end of pattern, accept immediately. */ | |
37 | if (!*pattern) | |
38 | return 1; | |
39 | ||
40 | /* If next character in pattern is known, optimize. */ | |
41 | if (*pattern != '?' && *pattern != '*') { | |
42 | /* | |
43 | * Look instances of the next character in | |
44 | * pattern, and try to match starting from | |
45 | * those. | |
46 | */ | |
47 | for (; *s; s++) | |
48 | if (*s == *pattern && | |
49 | match_pattern(s + 1, pattern + 1)) | |
50 | return 1; | |
51 | /* Failed. */ | |
52 | return 0; | |
53 | } | |
54 | /* | |
55 | * Move ahead one character at a time and try to | |
56 | * match at each position. | |
57 | */ | |
58 | for (; *s; s++) | |
59 | if (match_pattern(s, pattern)) | |
60 | return 1; | |
61 | /* Failed. */ | |
62 | return 0; | |
63 | } | |
64 | /* | |
65 | * There must be at least one more character in the string. | |
66 | * If we are at the end, fail. | |
67 | */ | |
68 | if (!*s) | |
69 | return 0; | |
70 | ||
71 | /* Check if the next character of the string is acceptable. */ | |
72 | if (*pattern != '?' && *pattern != *s) | |
73 | return 0; | |
74 | ||
75 | /* Move to the next character, both in string and in pattern. */ | |
76 | s++; | |
77 | pattern++; | |
78 | } | |
79 | /* NOTREACHED */ | |
80 | } | |
81 | ||
82 | /* | |
83 | * Tries to match the host name (which must be in all lowercase) against the | |
84 | * comma-separated sequence of subpatterns (each possibly preceded by ! to | |
85 | * indicate negation). Returns -1 if negation matches, 1 if there is | |
86 | * a positive match, 0 if there is no match at all. | |
87 | */ | |
88 | ||
89 | int | |
90 | match_hostname(const char *host, const char *pattern, u_int len) | |
91 | { | |
92 | char sub[1024]; | |
93 | int negated; | |
94 | int got_positive; | |
95 | u_int i, subi; | |
96 | ||
97 | got_positive = 0; | |
98 | for (i = 0; i < len;) { | |
99 | /* Check if the subpattern is negated. */ | |
100 | if (pattern[i] == '!') { | |
101 | negated = 1; | |
102 | i++; | |
103 | } else | |
104 | negated = 0; | |
105 | ||
106 | /* | |
107 | * Extract the subpattern up to a comma or end. Convert the | |
108 | * subpattern to lowercase. | |
109 | */ | |
110 | for (subi = 0; | |
111 | i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; | |
112 | subi++, i++) | |
113 | sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i]; | |
114 | /* If subpattern too long, return failure (no match). */ | |
115 | if (subi >= sizeof(sub) - 1) | |
116 | return 0; | |
117 | ||
118 | /* If the subpattern was terminated by a comma, skip the comma. */ | |
119 | if (i < len && pattern[i] == ',') | |
120 | i++; | |
121 | ||
122 | /* Null-terminate the subpattern. */ | |
123 | sub[subi] = '\0'; | |
124 | ||
125 | /* Try to match the subpattern against the host name. */ | |
126 | if (match_pattern(host, sub)) { | |
127 | if (negated) | |
128 | return -1; /* Negative */ | |
129 | else | |
130 | got_positive = 1; /* Positive */ | |
131 | } | |
132 | } | |
133 | ||
134 | /* | |
135 | * Return success if got a positive match. If there was a negative | |
136 | * match, we have already returned -1 and never get here. | |
137 | */ | |
138 | return got_positive; | |
139 | } |