1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
/*
* Copyright (c) 1995,1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#if !defined(_LIBC) && !defined(lint)
static const char rcsid[] = "$BINDId: ns_samedomain.c,v 8.9 1999/10/15 21:06:51 vixie Exp $";
#endif
#include <sys/types.h>
#include <arpa/nameser.h>
#include <errno.h>
#include <string.h>
/*
* int
* ns_samedomain(a, b)
* Check whether a name belongs to a domain.
* Inputs:
* a - the domain whose ancestory is being verified
* b - the potential ancestor we're checking against
* Return:
* boolean - is a at or below b?
* Notes:
* Trailing dots are first removed from name and domain.
* Always compare complete subdomains, not only whether the
* domain name is the trailing string of the given name.
*
* "host.foobar.top" lies in "foobar.top" and in "top" and in ""
* but NOT in "bar.top"
*/
int
ns_samedomain(const char *a, const char *b) {
size_t la, lb;
int diff, i, escaped;
const char *cp;
la = strlen(a);
lb = strlen(b);
/* Ignore a trailing label separator (i.e. an unescaped dot) in 'a'. */
if (la != 0 && a[la - 1] == '.') {
escaped = 0;
/* Note this loop doesn't get executed if la==1. */
for (i = la - 2; i >= 0; i--)
if (a[i] == '\\') {
if (escaped)
escaped = 0;
else
escaped = 1;
} else
break;
if (!escaped)
la--;
}
/* Ignore a trailing label separator (i.e. an unescaped dot) in 'b'. */
if (lb != 0 && b[lb - 1] == '.') {
escaped = 0;
/* note this loop doesn't get executed if lb==1 */
for (i = lb - 2; i >= 0; i--)
if (b[i] == '\\') {
if (escaped)
escaped = 0;
else
escaped = 1;
} else
break;
if (!escaped)
lb--;
}
/* lb == 0 means 'b' is the root domain, so 'a' must be in 'b'. */
if (lb == 0)
return (1);
/* 'b' longer than 'a' means 'a' can't be in 'b'. */
if (lb > la)
return (0);
/* 'a' and 'b' being equal at this point indicates sameness. */
if (lb == la)
return (strncasecmp(a, b, lb) == 0);
/* Ok, we know la > lb. */
diff = la - lb;
/*
* If 'a' is only 1 character longer than 'b', then it can't be
* a subdomain of 'b' (because of the need for the '.' label
* separator).
*/
if (diff < 2)
return (0);
/*
* If the character before the last 'lb' characters of 'b'
* isn't '.', then it can't be a match (this lets us avoid
* having "foobar.com" match "bar.com").
*/
if (a[diff - 1] != '.')
return (0);
/*
* We're not sure about that '.', however. It could be escaped
* and thus not a really a label separator.
*/
escaped = 0;
for (i = diff - 2; i >= 0; i--)
if (a[i] == '\\')
if (escaped)
escaped = 0;
else
escaped = 1;
else
break;
if (escaped)
return (0);
/* Now compare aligned trailing substring. */
cp = a + diff;
return (strncasecmp(cp, b, lb) == 0);
}
/*
* int
* ns_subdomain(a, b)
* is "a" a subdomain of "b"?
*/
int
ns_subdomain(const char *a, const char *b) {
return (ns_samename(a, b) != 1 && ns_samedomain(a, b));
}
/*
* int
* ns_makecanon(src, dst, dstsize)
* make a canonical copy of domain name "src"
* notes:
* foo -> foo.
* foo. -> foo.
* foo.. -> foo.
* foo\. -> foo\..
* foo\\. -> foo\\.
*/
int
ns_makecanon(const char *src, char *dst, size_t dstsize) {
size_t n = strlen(src);
if (n + sizeof "." > dstsize) {
__set_errno (EMSGSIZE);
return (-1);
}
strcpy(dst, src);
while (n > 0 && dst[n - 1] == '.') /* Ends in "." */
if (n > 1 && dst[n - 2] == '\\' && /* Ends in "\." */
(n < 2 || dst[n - 3] != '\\')) /* But not "\\." */
break;
else
dst[--n] = '\0';
dst[n++] = '.';
dst[n] = '\0';
return (0);
}
/*
* int
* ns_samename(a, b)
* determine whether domain name "a" is the same as domain name "b"
* return:
* -1 on error
* 0 if names differ
* 1 if names are the same
*/
int
ns_samename(const char *a, const char *b) {
char ta[NS_MAXDNAME], tb[NS_MAXDNAME];
if (ns_makecanon(a, ta, sizeof ta) < 0 ||
ns_makecanon(b, tb, sizeof tb) < 0)
return (-1);
if (strcasecmp(ta, tb) == 0)
return (1);
else
return (0);
}
|
