service/protocol-plugin/plugins/mqtt-fan/lib/tls_mosq.c

   1 /*
   2 Copyright (c) 2013 Roger Light <roger@atchoo.org>
   3 All rights reserved.
   4
   5 Redistribution and use in source and binary forms, with or without
   6 modification, are permitted provided that the following conditions are met:
   7
   8 1. Redistributions of source code must retain the above copyright notice,
   9    this list of conditions and the following disclaimer.
  10 2. Redistributions in binary form must reproduce the above copyright
  11    notice, this list of conditions and the following disclaimer in the
  12    documentation and/or other materials provided with the distribution.
  13 3. Neither the name of mosquitto nor the names of its
  14    contributors may be used to endorse or promote products derived from
  15    this software without specific prior written permission.
  16
  17 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  18 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  21 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27 POSSIBILITY OF SUCH DAMAGE.
  28 */
  29
  30 #ifdef WITH_TLS
  31
  32 #ifdef WIN32
  33 #  include <winsock2.h>
  34 #  include <ws2tcpip.h>
  35 #else
  36 #  include <arpa/inet.h>
  37 #endif
  38
  39 #include <string.h>
  40 #include <openssl/conf.h>
  41 #include <openssl/x509v3.h>
  42 #include <openssl/ssl.h>
  43
  44 #ifdef WITH_BROKER
  45 #  include "mosquitto_broker.h"
  46 #endif
  47 #include "mosquitto_internal.h"
  48 #include "tls_mosq.h"
  49
  50 extern int tls_ex_index_mosq;
  51
  52 int _mosquitto_server_certificate_verify(int preverify_ok, X509_STORE_CTX *ctx)
  53 {
  54         /* Preverify should have already checked expiry, revocation.
  55          * We need to verify the hostname. */
  56         struct mosquitto *mosq;
  57         SSL *ssl;
  58         X509 *cert;
  59
  60         /* Always reject if preverify_ok has failed. */
  61         if(!preverify_ok) return 0;
  62
  63         ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
  64         mosq = SSL_get_ex_data(ssl, tls_ex_index_mosq);
  65         if(!mosq) return 0;
  66
  67         if(mosq->tls_insecure == false){
  68                 if(X509_STORE_CTX_get_error_depth(ctx) == 0){
  69                         /* FIXME - use X509_check_host() etc. for sufficiently new openssl (>=1.1.x) */
  70                         cert = X509_STORE_CTX_get_current_cert(ctx);
  71                         /* This is the peer certificate, all others are upwards in the chain. */
  72 #if defined(WITH_BROKER)
  73                         return _mosquitto_verify_certificate_hostname(cert, mosq->bridge->addresses[mosq->bridge->cur_address].address);
  74 #else
  75                         return _mosquitto_verify_certificate_hostname(cert, mosq->host);
  76 #endif
  77                 }else{
  78                         return preverify_ok;
  79                 }
  80         }else{
  81                 return preverify_ok;
  82         }
  83 }
  84
  85 /* This code is based heavily on the example provided in "Secure Programming
  86  * Cookbook for C and C++".
  87  */
  88 int _mosquitto_verify_certificate_hostname(X509 *cert, const char *hostname)
  89 {
  90         int i;
  91         char name[256];
  92         X509_NAME *subj;
  93         bool have_san_dns = false;
  94         STACK_OF(GENERAL_NAME) *san;
  95         const GENERAL_NAME *nval;
  96         const unsigned char *data;
  97         unsigned char ipv6_addr[16];
  98         unsigned char ipv4_addr[4];
  99         int ipv6_ok;
 100         int ipv4_ok;
 101
 102 #ifdef WIN32
 103         ipv6_ok = InetPton(AF_INET6, hostname, &ipv6_addr);
 104         ipv4_ok = InetPton(AF_INET, hostname, &ipv4_addr);
 105 #else
 106         ipv6_ok = inet_pton(AF_INET6, hostname, &ipv6_addr);
 107         ipv4_ok = inet_pton(AF_INET, hostname, &ipv4_addr);
 108 #endif
 109
 110         san = X509_get_ext_d2i(cert, NID_subject_alt_name, NULL, NULL);
 111         if(san){
 112                 for(i=0; i<sk_GENERAL_NAME_num(san); i++){
 113                         nval = sk_GENERAL_NAME_value(san, i);
 114                         if(nval->type == GEN_DNS){
 115                                 data = ASN1_STRING_data(nval->d.dNSName);
 116                                 if(data && !strcasecmp((char *)data, hostname)){
 117                                         return 1;
 118                                 }
 119                                 have_san_dns = true;
 120                         }else if(nval->type == GEN_IPADD){
 121                                 data = ASN1_STRING_data(nval->d.iPAddress);
 122                                 if(nval->d.iPAddress->length == 4 && ipv4_ok){
 123                                         if(!memcmp(ipv4_addr, data, 4)){
 124                                                 return 1;
 125                                         }
 126                                 }else if(nval->d.iPAddress->length == 16 && ipv6_ok){
 127                                         if(!memcmp(ipv6_addr, data, 16)){
 128                                                 return 1;
 129                                         }
 130                                 }
 131                         }
 132                 }
 133                 if(have_san_dns){
 134                         /* Only check CN if subjectAltName DNS entry does not exist. */
 135                         return 0;
 136                 }
 137         }
 138         subj = X509_get_subject_name(cert);
 139         if(X509_NAME_get_text_by_NID(subj, NID_commonName, name, sizeof(name)) > 0){
 140                 name[sizeof(name) - 1] = '\0';
 141                 if (!strcasecmp(name, hostname)) return 1;
 142         }
 143         return 0;
 144 }
 145
 146 #endif
 147