1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2015, 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.haxx.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 ***************************************************************************/
22
23#include "curl_setup.h"
24
25#if defined(USE_OPENSSL) || defined(USE_AXTLS) || defined(USE_GSKIT)
26/* these backends use functions from this file */
27
28#ifdef HAVE_NETINET_IN_H
29#include <netinet/in.h>
30#endif
31
32#include "hostcheck.h"
33#include "rawstr.h"
34#include "inet_pton.h"
35
36#include "curl_memory.h"
37/* The last #include file should be: */
38#include "memdebug.h"
39
40/*
41 * Match a hostname against a wildcard pattern.
42 * E.g.
43 *  "foo.host.com" matches "*.host.com".
44 *
45 * We use the matching rule described in RFC6125, section 6.4.3.
46 * https://tools.ietf.org/html/rfc6125#section-6.4.3
47 *
48 * In addition: ignore trailing dots in the host names and wildcards, so that
49 * the names are used normalized. This is what the browsers do.
50 *
51 * Do not allow wildcard matching on IP numbers. There are apparently
52 * certificates being used with an IP address in the CN field, thus making no
53 * apparent distinction between a name and an IP. We need to detect the use of
54 * an IP address and not wildcard match on such names.
55 *
56 * NOTE: hostmatch() gets called with copied buffers so that it can modify the
57 * contents at will.
58 */
59
60static int hostmatch(char *hostname, char *pattern)
61{
62  const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
63  int wildcard_enabled;
64  size_t prefixlen, suffixlen;
65  struct in_addr ignored;
66#ifdef ENABLE_IPV6
67  struct sockaddr_in6 si6;
68#endif
69
70  /* normalize pattern and hostname by stripping off trailing dots */
71  size_t len = strlen(hostname);
72  if(hostname[len-1]=='.')
73    hostname[len-1]=0;
74  len = strlen(pattern);
75  if(pattern[len-1]=='.')
76    pattern[len-1]=0;
77
78  pattern_wildcard = strchr(pattern, '*');
79  if(pattern_wildcard == NULL)
80    return Curl_raw_equal(pattern, hostname) ?
81      CURL_HOST_MATCH : CURL_HOST_NOMATCH;
82
83  /* detect IP address as hostname and fail the match if so */
84  if(Curl_inet_pton(AF_INET, hostname, &ignored) > 0)
85    return CURL_HOST_NOMATCH;
86#ifdef ENABLE_IPV6
87  else if(Curl_inet_pton(AF_INET6, hostname, &si6.sin6_addr) > 0)
88    return CURL_HOST_NOMATCH;
89#endif
90
91  /* We require at least 2 dots in pattern to avoid too wide wildcard
92     match. */
93  wildcard_enabled = 1;
94  pattern_label_end = strchr(pattern, '.');
95  if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
96     pattern_wildcard > pattern_label_end ||
97     Curl_raw_nequal(pattern, "xn--", 4)) {
98    wildcard_enabled = 0;
99  }
100  if(!wildcard_enabled)
101    return Curl_raw_equal(pattern, hostname) ?
102      CURL_HOST_MATCH : CURL_HOST_NOMATCH;
103
104  hostname_label_end = strchr(hostname, '.');
105  if(hostname_label_end == NULL ||
106     !Curl_raw_equal(pattern_label_end, hostname_label_end))
107    return CURL_HOST_NOMATCH;
108
109  /* The wildcard must match at least one character, so the left-most
110     label of the hostname is at least as large as the left-most label
111     of the pattern. */
112  if(hostname_label_end - hostname < pattern_label_end - pattern)
113    return CURL_HOST_NOMATCH;
114
115  prefixlen = pattern_wildcard - pattern;
116  suffixlen = pattern_label_end - (pattern_wildcard+1);
117  return Curl_raw_nequal(pattern, hostname, prefixlen) &&
118    Curl_raw_nequal(pattern_wildcard+1, hostname_label_end - suffixlen,
119                    suffixlen) ?
120    CURL_HOST_MATCH : CURL_HOST_NOMATCH;
121}
122
123int Curl_cert_hostcheck(const char *match_pattern, const char *hostname)
124{
125  char *matchp;
126  char *hostp;
127  int res = 0;
128  if(!match_pattern || !*match_pattern ||
129      !hostname || !*hostname) /* sanity check */
130    ;
131  else {
132    matchp = strdup(match_pattern);
133    if(matchp) {
134      hostp = strdup(hostname);
135      if(hostp) {
136        if(hostmatch(hostp, matchp) == CURL_HOST_MATCH)
137          res= 1;
138        free(hostp);
139      }
140      free(matchp);
141    }
142  }
143
144  return res;
145}
146
147#endif /* OPENSSL or AXTLS or GSKIT */
148