summaryrefslogtreecommitdiff
path: root/libcurl/src/lib/hostcheck.c
blob: 1bc330db224d995e9097c6b7a6b464b079ccf695 (plain)
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
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

#include "curl_setup.h"

#if defined(USE_OPENSSL) || defined(USE_AXTLS) || defined(USE_GSKIT)
/* these backends use functions from this file */

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#include "hostcheck.h"
#include "rawstr.h"
#include "inet_pton.h"

#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"

/*
 * Match a hostname against a wildcard pattern.
 * E.g.
 *  "foo.host.com" matches "*.host.com".
 *
 * We use the matching rule described in RFC6125, section 6.4.3.
 * http://tools.ietf.org/html/rfc6125#section-6.4.3
 *
 * In addition: ignore trailing dots in the host names and wildcards, so that
 * the names are used normalized. This is what the browsers do.
 *
 * Do not allow wildcard matching on IP numbers. There are apparently
 * certificates being used with an IP address in the CN field, thus making no
 * apparent distinction between a name and an IP. We need to detect the use of
 * an IP address and not wildcard match on such names.
 *
 * NOTE: hostmatch() gets called with copied buffers so that it can modify the
 * contents at will.
 */

static int hostmatch(char *hostname, char *pattern)
{
  const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
  int wildcard_enabled;
  size_t prefixlen, suffixlen;
  struct in_addr ignored;
#ifdef ENABLE_IPV6
  struct sockaddr_in6 si6;
#endif

  /* normalize pattern and hostname by stripping off trailing dots */
  size_t len = strlen(hostname);
  if(hostname[len-1]=='.')
    hostname[len-1]=0;
  len = strlen(pattern);
  if(pattern[len-1]=='.')
    pattern[len-1]=0;

  pattern_wildcard = strchr(pattern, '*');
  if(pattern_wildcard == NULL)
    return Curl_raw_equal(pattern, hostname) ?
      CURL_HOST_MATCH : CURL_HOST_NOMATCH;

  /* detect IP address as hostname and fail the match if so */
  if(Curl_inet_pton(AF_INET, hostname, &ignored) > 0)
    return CURL_HOST_NOMATCH;
#ifdef ENABLE_IPV6
  else if(Curl_inet_pton(AF_INET6, hostname, &si6.sin6_addr) > 0)
    return CURL_HOST_NOMATCH;
#endif

  /* We require at least 2 dots in pattern to avoid too wide wildcard
     match. */
  wildcard_enabled = 1;
  pattern_label_end = strchr(pattern, '.');
  if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
     pattern_wildcard > pattern_label_end ||
     Curl_raw_nequal(pattern, "xn--", 4)) {
    wildcard_enabled = 0;
  }
  if(!wildcard_enabled)
    return Curl_raw_equal(pattern, hostname) ?
      CURL_HOST_MATCH : CURL_HOST_NOMATCH;

  hostname_label_end = strchr(hostname, '.');
  if(hostname_label_end == NULL ||
     !Curl_raw_equal(pattern_label_end, hostname_label_end))
    return CURL_HOST_NOMATCH;

  /* The wildcard must match at least one character, so the left-most
     label of the hostname is at least as large as the left-most label
     of the pattern. */
  if(hostname_label_end - hostname < pattern_label_end - pattern)
    return CURL_HOST_NOMATCH;

  prefixlen = pattern_wildcard - pattern;
  suffixlen = pattern_label_end - (pattern_wildcard+1);
  return Curl_raw_nequal(pattern, hostname, prefixlen) &&
    Curl_raw_nequal(pattern_wildcard+1, hostname_label_end - suffixlen,
                    suffixlen) ?
    CURL_HOST_MATCH : CURL_HOST_NOMATCH;
}

CURL_STATIC int Curl_cert_hostcheck(const char *match_pattern, const char *hostname)
{
  char *matchp;
  char *hostp;
  int res = 0;
  if(!match_pattern || !*match_pattern ||
      !hostname || !*hostname) /* sanity check */
    ;
  else {
    matchp = strdup(match_pattern);
    if(matchp) {
      hostp = strdup(hostname);
      if(hostp) {
        if(hostmatch(hostp, matchp) == CURL_HOST_MATCH)
          res= 1;
        free(hostp);
      }
      free(matchp);
    }
  }

  return res;
}

#endif /* OPENSSL or AXTLS or GSKIT */