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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: *
1.6.2.3 ! jason 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: */
1.1 deraadt 13:
14: #include "includes.h"
1.6.2.3 ! jason 15: RCSID("$OpenBSD: match.c,v 1.9 2000/09/07 20:27:52 deraadt Exp $");
1.1 deraadt 16:
17: #include "ssh.h"
18:
1.4 markus 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: */
1.2 markus 23:
1.6 markus 24: int
1.2 markus 25: match_pattern(const char *s, const char *pattern)
1.1 deraadt 26: {
1.2 markus 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 != '*') {
1.4 markus 42: /*
43: * Look instances of the next character in
44: * pattern, and try to match starting from
45: * those.
46: */
1.2 markus 47: for (; *s; s++)
48: if (*s == *pattern &&
49: match_pattern(s + 1, pattern + 1))
50: return 1;
51: /* Failed. */
52: return 0;
53: }
1.4 markus 54: /*
55: * Move ahead one character at a time and try to
56: * match at each position.
57: */
1.2 markus 58: for (; *s; s++)
59: if (match_pattern(s, pattern))
60: return 1;
61: /* Failed. */
62: return 0;
63: }
1.4 markus 64: /*
65: * There must be at least one more character in the string.
66: * If we are at the end, fail.
67: */
1.2 markus 68: if (!*s)
69: return 0;
70:
1.4 markus 71: /* Check if the next character of the string is acceptable. */
1.2 markus 72: if (*pattern != '?' && *pattern != *s)
73: return 0;
74:
1.4 markus 75: /* Move to the next character, both in string and in pattern. */
1.2 markus 76: s++;
77: pattern++;
78: }
79: /* NOTREACHED */
1.5 markus 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
1.6.2.1 jason 85: * indicate negation). Returns -1 if negation matches, 1 if there is
86: * a positive match, 0 if there is no match at all.
1.5 markus 87: */
88:
89: int
90: match_hostname(const char *host, const char *pattern, unsigned int len)
91: {
92: char sub[1024];
93: int negated;
94: int got_positive;
95: unsigned 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)
1.6.2.1 jason 128: return -1; /* Negative */
1.5 markus 129: else
1.6.2.1 jason 130: got_positive = 1; /* Positive */
1.5 markus 131: }
132: }
133:
134: /*
135: * Return success if got a positive match. If there was a negative
1.6.2.1 jason 136: * match, we have already returned -1 and never get here.
1.5 markus 137: */
138: return got_positive;
1.1 deraadt 139: }