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    1: /***************************************************************************
    2:  *                                  _   _ ____  _
    3:  *  Project                     ___| | | |  _ \| |
    4:  *                             / __| | | | |_) | |
    5:  *                            | (__| |_| |  _ <| |___
    6:  *                             \___|\___/|_| \_\_____|
    7:  *
    8:  * Copyright (C) 1998 - 2019, 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)                                \
   26:   || defined(USE_GSKIT)                                 \
   27:   || defined(USE_SCHANNEL)
   28: /* these backends use functions from this file */
   29: 
   30: #ifdef HAVE_NETINET_IN_H
   31: #include <netinet/in.h>
   32: #endif
   33: #ifdef HAVE_NETINET_IN6_H
   34: #include <netinet/in6.h>
   35: #endif
   36: 
   37: #include "hostcheck.h"
   38: #include "strcase.h"
   39: #include "inet_pton.h"
   40: 
   41: #include "curl_memory.h"
   42: /* The last #include file should be: */
   43: #include "memdebug.h"
   44: 
   45: /*
   46:  * Match a hostname against a wildcard pattern.
   47:  * E.g.
   48:  *  "foo.host.com" matches "*.host.com".
   49:  *
   50:  * We use the matching rule described in RFC6125, section 6.4.3.
   51:  * https://tools.ietf.org/html/rfc6125#section-6.4.3
   52:  *
   53:  * In addition: ignore trailing dots in the host names and wildcards, so that
   54:  * the names are used normalized. This is what the browsers do.
   55:  *
   56:  * Do not allow wildcard matching on IP numbers. There are apparently
   57:  * certificates being used with an IP address in the CN field, thus making no
   58:  * apparent distinction between a name and an IP. We need to detect the use of
   59:  * an IP address and not wildcard match on such names.
   60:  *
   61:  * NOTE: hostmatch() gets called with copied buffers so that it can modify the
   62:  * contents at will.
   63:  */
   64: 
   65: static int hostmatch(char *hostname, char *pattern)
   66: {
   67:   const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
   68:   int wildcard_enabled;
   69:   size_t prefixlen, suffixlen;
   70:   struct in_addr ignored;
   71: #ifdef ENABLE_IPV6
   72:   struct sockaddr_in6 si6;
   73: #endif
   74: 
   75:   /* normalize pattern and hostname by stripping off trailing dots */
   76:   size_t len = strlen(hostname);
   77:   if(hostname[len-1]=='.')
   78:     hostname[len-1] = 0;
   79:   len = strlen(pattern);
   80:   if(pattern[len-1]=='.')
   81:     pattern[len-1] = 0;
   82: 
   83:   pattern_wildcard = strchr(pattern, '*');
   84:   if(pattern_wildcard == NULL)
   85:     return strcasecompare(pattern, hostname) ?
   86:       CURL_HOST_MATCH : CURL_HOST_NOMATCH;
   87: 
   88:   /* detect IP address as hostname and fail the match if so */
   89:   if(Curl_inet_pton(AF_INET, hostname, &ignored) > 0)
   90:     return CURL_HOST_NOMATCH;
   91: #ifdef ENABLE_IPV6
   92:   if(Curl_inet_pton(AF_INET6, hostname, &si6.sin6_addr) > 0)
   93:     return CURL_HOST_NOMATCH;
   94: #endif
   95: 
   96:   /* We require at least 2 dots in pattern to avoid too wide wildcard
   97:      match. */
   98:   wildcard_enabled = 1;
   99:   pattern_label_end = strchr(pattern, '.');
  100:   if(pattern_label_end == NULL || strchr(pattern_label_end + 1, '.') == NULL ||
  101:      pattern_wildcard > pattern_label_end ||
  102:      strncasecompare(pattern, "xn--", 4)) {
  103:     wildcard_enabled = 0;
  104:   }
  105:   if(!wildcard_enabled)
  106:     return strcasecompare(pattern, hostname) ?
  107:       CURL_HOST_MATCH : CURL_HOST_NOMATCH;
  108: 
  109:   hostname_label_end = strchr(hostname, '.');
  110:   if(hostname_label_end == NULL ||
  111:      !strcasecompare(pattern_label_end, hostname_label_end))
  112:     return CURL_HOST_NOMATCH;
  113: 
  114:   /* The wildcard must match at least one character, so the left-most
  115:      label of the hostname is at least as large as the left-most label
  116:      of the pattern. */
  117:   if(hostname_label_end - hostname < pattern_label_end - pattern)
  118:     return CURL_HOST_NOMATCH;
  119: 
  120:   prefixlen = pattern_wildcard - pattern;
  121:   suffixlen = pattern_label_end - (pattern_wildcard + 1);
  122:   return strncasecompare(pattern, hostname, prefixlen) &&
  123:     strncasecompare(pattern_wildcard + 1, hostname_label_end - suffixlen,
  124:                     suffixlen) ?
  125:     CURL_HOST_MATCH : CURL_HOST_NOMATCH;
  126: }
  127: 
  128: int Curl_cert_hostcheck(const char *match_pattern, const char *hostname)
  129: {
  130:   int res = 0;
  131:   if(!match_pattern || !*match_pattern ||
  132:       !hostname || !*hostname) /* sanity check */
  133:     ;
  134:   else {
  135:     char *matchp = strdup(match_pattern);
  136:     if(matchp) {
  137:       char *hostp = strdup(hostname);
  138:       if(hostp) {
  139:         if(hostmatch(hostp, matchp) == CURL_HOST_MATCH)
  140:           res = 1;
  141:         free(hostp);
  142:       }
  143:       free(matchp);
  144:     }
  145:   }
  146: 
  147:   return res;
  148: }
  149: 
  150: #endif /* OPENSSL, GSKIT or schannel+wince */