1 /***************************************************************************
3 * Project ___| | | | _ \| |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
8 * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
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.
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.
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
21 ***************************************************************************/
23 #include "curl_setup.h"
25 #if defined(USE_OPENSSL) \
26 || defined(USE_GSKIT) \
27 || defined(USE_SCHANNEL)
28 /* these backends use functions from this file */
30 #ifdef HAVE_NETINET_IN_H
31 #include <netinet/in.h>
33 #ifdef HAVE_NETINET_IN6_H
34 #include <netinet/in6.h>
36 #include "curl_memrchr.h"
38 #include "hostcheck.h"
42 #include "curl_memory.h"
43 /* The last #include file should be: */
46 /* check the two input strings with given length, but do not
47 assume they end in nul-bytes */
48 static bool pmatch(const char *hostname, size_t hostlen,
49 const char *pattern, size_t patternlen)
51 if(hostlen != patternlen)
53 return strncasecompare(hostname, pattern, hostlen);
57 * Match a hostname against a wildcard pattern.
59 * "foo.host.com" matches "*.host.com".
61 * We use the matching rule described in RFC6125, section 6.4.3.
62 * https://datatracker.ietf.org/doc/html/rfc6125#section-6.4.3
64 * In addition: ignore trailing dots in the host names and wildcards, so that
65 * the names are used normalized. This is what the browsers do.
67 * Do not allow wildcard matching on IP numbers. There are apparently
68 * certificates being used with an IP address in the CN field, thus making no
69 * apparent distinction between a name and an IP. We need to detect the use of
70 * an IP address and not wildcard match on such names.
72 * Return TRUE on a match. FALSE if not.
75 static bool hostmatch(const char *hostname,
80 const char *pattern_label_end, *wildcard, *hostname_label_end;
81 size_t prefixlen, suffixlen;
83 /* normalize pattern and hostname by stripping off trailing dots */
84 DEBUGASSERT(patternlen);
85 if(hostname[hostlen-1]=='.')
87 if(pattern[patternlen-1]=='.')
90 wildcard = memchr(pattern, '*', patternlen);
92 return pmatch(hostname, hostlen, pattern, patternlen);
94 /* detect IP address as hostname and fail the match if so */
95 if(Curl_host_is_ipnum(hostname))
98 /* We require at least 2 dots in the pattern to avoid too wide wildcard
100 pattern_label_end = memchr(pattern, '.', patternlen);
101 if(!pattern_label_end ||
102 (memrchr(pattern, '.', patternlen) == pattern_label_end) ||
103 strncasecompare(pattern, "xn--", 4))
104 return pmatch(hostname, hostlen, pattern, patternlen);
106 hostname_label_end = memchr(hostname, '.', hostlen);
107 if(!hostname_label_end)
110 size_t skiphost = hostname_label_end - hostname;
111 size_t skiplen = pattern_label_end - pattern;
112 if(!pmatch(hostname_label_end, hostlen - skiphost,
113 pattern_label_end, patternlen - skiplen))
116 /* The wildcard must match at least one character, so the left-most
117 label of the hostname is at least as large as the left-most label
119 if(hostname_label_end - hostname < pattern_label_end - pattern)
122 prefixlen = wildcard - pattern;
123 suffixlen = pattern_label_end - (wildcard + 1);
124 return strncasecompare(pattern, hostname, prefixlen) &&
125 strncasecompare(wildcard + 1, hostname_label_end - suffixlen,
126 suffixlen) ? TRUE : FALSE;
130 * Curl_cert_hostcheck() returns TRUE if a match and FALSE if not.
132 bool Curl_cert_hostcheck(const char *match, size_t matchlen,
133 const char *hostname, size_t hostlen)
135 if(match && *match && hostname && *hostname)
136 return hostmatch(hostname, hostlen, match, matchlen);
140 #endif /* OPENSSL, GSKIT or schannel+wince */