1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25#include "curl_setup.h"
26
27#if defined(USE_OPENSSL) \
28 || defined(USE_SCHANNEL)
29/* these backends use functions from this file */
30
31#ifdef HAVE_NETINET_IN_H
32#include <netinet/in.h>
33#endif
34#ifdef HAVE_NETINET_IN6_H
35#include <netinet/in6.h>
36#endif
37#include "curl_memrchr.h"
38
39#include "hostcheck.h"
40#include "strcase.h"
41#include "hostip.h"
42
43#include "curl_memory.h"
44/* The last #include file should be: */
45#include "memdebug.h"
46
47/* check the two input strings with given length, but do not
48 assume they end in nul-bytes */
49static bool pmatch(const char *hostname, size_t hostlen,
50 const char *pattern, size_t patternlen)
51{
52 if(hostlen != patternlen)
53 return FALSE;
54 return strncasecompare(hostname, pattern, hostlen);
55}
56
57/*
58 * Match a hostname against a wildcard pattern.
59 * E.g.
60 * "foo.host.com" matches "*.host.com".
61 *
62 * We use the matching rule described in RFC6125, section 6.4.3.
63 * https://datatracker.ietf.org/doc/html/rfc6125#section-6.4.3
64 *
65 * In addition: ignore trailing dots in the host names and wildcards, so that
66 * the names are used normalized. This is what the browsers do.
67 *
68 * Do not allow wildcard matching on IP numbers. There are apparently
69 * certificates being used with an IP address in the CN field, thus making no
70 * apparent distinction between a name and an IP. We need to detect the use of
71 * an IP address and not wildcard match on such names.
72 *
73 * Only match on "*" being used for the leftmost label, not "a*", "a*b" nor
74 * "*b".
75 *
76 * Return TRUE on a match. FALSE if not.
77 *
78 * @unittest: 1397
79 */
80
81static bool hostmatch(const char *hostname,
82 size_t hostlen,
83 const char *pattern,
84 size_t patternlen)
85{
86 const char *pattern_label_end;
87
88 DEBUGASSERT(pattern);
89 DEBUGASSERT(patternlen);
90 DEBUGASSERT(hostname);
91 DEBUGASSERT(hostlen);
92
93 /* normalize pattern and hostname by stripping off trailing dots */
94 if(hostname[hostlen-1]=='.')
95 hostlen--;
96 if(pattern[patternlen-1]=='.')
97 patternlen--;
98
99 if(strncmp(s1: pattern, s2: "*.", n: 2))
100 return pmatch(hostname, hostlen, pattern, patternlen);
101
102 /* detect IP address as hostname and fail the match if so */
103 else if(Curl_host_is_ipnum(hostname))
104 return FALSE;
105
106 /* We require at least 2 dots in the pattern to avoid too wide wildcard
107 match. */
108 pattern_label_end = memchr(s: pattern, c: '.', n: patternlen);
109 if(!pattern_label_end ||
110 (memrchr(pattern, '.', patternlen) == pattern_label_end))
111 return pmatch(hostname, hostlen, pattern, patternlen);
112 else {
113 const char *hostname_label_end = memchr(s: hostname, c: '.', n: hostlen);
114 if(hostname_label_end) {
115 size_t skiphost = hostname_label_end - hostname;
116 size_t skiplen = pattern_label_end - pattern;
117 return pmatch(hostname: hostname_label_end, hostlen: hostlen - skiphost,
118 pattern: pattern_label_end, patternlen: patternlen - skiplen);
119 }
120 }
121 return FALSE;
122}
123
124/*
125 * Curl_cert_hostcheck() returns TRUE if a match and FALSE if not.
126 */
127bool Curl_cert_hostcheck(const char *match, size_t matchlen,
128 const char *hostname, size_t hostlen)
129{
130 if(match && *match && hostname && *hostname)
131 return hostmatch(hostname, hostlen, pattern: match, patternlen: matchlen);
132 return FALSE;
133}
134
135#endif /* OPENSSL or SCHANNEL */
136