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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel (at) 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 http://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  * http://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 
     60 static 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 
    123 int 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