1 | /********************************************************************\ |
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2 | * BitlBee -- An IRC to other IM-networks gateway * |
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3 | * * |
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4 | * Copyright 2002-2012 Wilmer van der Gaast and others * |
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5 | \********************************************************************/ |
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6 | |
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7 | /* SSL module - GnuTLS version */ |
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8 | |
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9 | /* |
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10 | This program is free software; you can redistribute it and/or modify |
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11 | it under the terms of the GNU General Public License as published by |
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12 | the Free Software Foundation; either version 2 of the License, or |
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13 | (at your option) any later version. |
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14 | |
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15 | This program is distributed in the hope that it will be useful, |
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16 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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18 | GNU General Public License for more details. |
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19 | |
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20 | You should have received a copy of the GNU General Public License with |
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21 | the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL; |
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22 | if not, write to the Free Software Foundation, Inc., 59 Temple Place, |
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23 | Suite 330, Boston, MA 02111-1307 USA |
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24 | */ |
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25 | |
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26 | #include <gnutls/gnutls.h> |
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27 | #include <gnutls/x509.h> |
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28 | #include <gcrypt.h> |
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29 | #include <fcntl.h> |
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30 | #include <unistd.h> |
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31 | #include "proxy.h" |
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32 | #include "ssl_client.h" |
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33 | #include "sock.h" |
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34 | #include "stdlib.h" |
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35 | #include "bitlbee.h" |
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36 | |
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37 | int ssl_errno = 0; |
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38 | |
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39 | static gboolean initialized = FALSE; |
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40 | gnutls_certificate_credentials_t xcred; |
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41 | |
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42 | #include <limits.h> |
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43 | |
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44 | #if defined(ULONG_MAX) && ULONG_MAX > 4294967295UL |
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45 | #define GNUTLS_STUPID_CAST (long) |
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46 | #else |
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47 | #define GNUTLS_STUPID_CAST (int) |
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48 | #endif |
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49 | |
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50 | #define SSLDEBUG 0 |
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51 | |
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52 | struct scd |
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53 | { |
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54 | ssl_input_function func; |
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55 | gpointer data; |
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56 | int fd; |
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57 | gboolean established; |
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58 | int inpa; |
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59 | char *hostname; |
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60 | gboolean verify; |
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61 | |
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62 | gnutls_session_t session; |
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63 | }; |
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64 | |
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65 | static GHashTable *session_cache; |
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66 | |
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67 | static gboolean ssl_connected( gpointer data, gint source, b_input_condition cond ); |
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68 | static gboolean ssl_starttls_real( gpointer data, gint source, b_input_condition cond ); |
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69 | static gboolean ssl_handshake( gpointer data, gint source, b_input_condition cond ); |
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70 | |
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71 | static void ssl_deinit( void ); |
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72 | |
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73 | static void ssl_log( int level, const char *line ) |
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74 | { |
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75 | printf( "%d %s", level, line ); |
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76 | } |
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77 | |
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78 | void ssl_init( void ) |
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79 | { |
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80 | if( initialized ) |
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81 | return; |
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82 | |
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83 | gnutls_global_init(); |
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84 | gnutls_certificate_allocate_credentials( &xcred ); |
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85 | if( global.conf->cafile ) |
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86 | { |
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87 | gnutls_certificate_set_x509_trust_file( xcred, global.conf->cafile, GNUTLS_X509_FMT_PEM ); |
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88 | |
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89 | /* Not needed in GnuTLS 2.11+ (enabled by default there) so |
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90 | don't do it (resets possible other defaults). */ |
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91 | if( !gnutls_check_version( "2.11" ) ) |
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92 | gnutls_certificate_set_verify_flags( xcred, GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT ); |
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93 | } |
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94 | initialized = TRUE; |
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95 | |
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96 | gnutls_global_set_log_function( ssl_log ); |
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97 | /* |
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98 | gnutls_global_set_log_level( 3 ); |
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99 | */ |
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100 | |
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101 | session_cache = g_hash_table_new_full( g_str_hash, g_str_equal, g_free, g_free ); |
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102 | |
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103 | atexit( ssl_deinit ); |
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104 | } |
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105 | |
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106 | static void ssl_deinit( void ) |
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107 | { |
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108 | gnutls_global_deinit(); |
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109 | gnutls_certificate_free_credentials( xcred ); |
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110 | g_hash_table_destroy( session_cache ); |
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111 | session_cache = NULL; |
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112 | } |
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113 | |
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114 | void *ssl_connect( char *host, int port, gboolean verify, ssl_input_function func, gpointer data ) |
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115 | { |
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116 | struct scd *conn = g_new0( struct scd, 1 ); |
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117 | |
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118 | conn->func = func; |
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119 | conn->data = data; |
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120 | conn->inpa = -1; |
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121 | conn->hostname = g_strdup( host ); |
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122 | conn->verify = verify && global.conf->cafile; |
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123 | conn->fd = proxy_connect( host, port, ssl_connected, conn ); |
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124 | |
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125 | if( conn->fd < 0 ) |
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126 | { |
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127 | g_free( conn ); |
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128 | return NULL; |
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129 | } |
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130 | |
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131 | return conn; |
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132 | } |
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133 | |
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134 | void *ssl_starttls( int fd, char *hostname, gboolean verify, ssl_input_function func, gpointer data ) |
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135 | { |
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136 | struct scd *conn = g_new0( struct scd, 1 ); |
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137 | |
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138 | conn->fd = fd; |
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139 | conn->func = func; |
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140 | conn->data = data; |
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141 | conn->inpa = -1; |
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142 | conn->hostname = g_strdup( hostname ); |
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143 | |
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144 | /* For now, SSL verification is globally enabled by setting the cafile |
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145 | setting in bitlbee.conf. Commented out by default because probably |
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146 | not everyone has this file in the same place and plenty of folks |
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147 | may not have the cert of their private Jabber server in it. */ |
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148 | conn->verify = verify && global.conf->cafile; |
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149 | |
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150 | /* This function should be called via a (short) timeout instead of |
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151 | directly from here, because these SSL calls are *supposed* to be |
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152 | *completely* asynchronous and not ready yet when this function |
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153 | (or *_connect, for examle) returns. Also, errors are reported via |
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154 | the callback function, not via this function's return value. |
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155 | |
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156 | In short, doing things like this makes the rest of the code a lot |
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157 | simpler. */ |
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158 | |
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159 | b_timeout_add( 1, ssl_starttls_real, conn ); |
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160 | |
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161 | return conn; |
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162 | } |
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163 | |
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164 | static gboolean ssl_starttls_real( gpointer data, gint source, b_input_condition cond ) |
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165 | { |
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166 | struct scd *conn = data; |
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167 | |
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168 | return ssl_connected( conn, conn->fd, B_EV_IO_WRITE ); |
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169 | } |
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170 | |
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171 | static int verify_certificate_callback( gnutls_session_t session ) |
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172 | { |
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173 | unsigned int status; |
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174 | const gnutls_datum_t *cert_list; |
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175 | unsigned int cert_list_size; |
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176 | int gnutlsret; |
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177 | int verifyret = 0; |
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178 | gnutls_x509_crt_t cert; |
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179 | struct scd *conn; |
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180 | |
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181 | conn = gnutls_session_get_ptr( session ); |
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182 | |
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183 | gnutlsret = gnutls_certificate_verify_peers2( session, &status ); |
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184 | if( gnutlsret < 0 ) |
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185 | return VERIFY_CERT_ERROR; |
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186 | |
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187 | if( status & GNUTLS_CERT_INVALID ) |
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188 | verifyret |= VERIFY_CERT_INVALID; |
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189 | |
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190 | if( status & GNUTLS_CERT_REVOKED ) |
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191 | verifyret |= VERIFY_CERT_REVOKED; |
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192 | |
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193 | if( status & GNUTLS_CERT_SIGNER_NOT_FOUND ) |
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194 | verifyret |= VERIFY_CERT_SIGNER_NOT_FOUND; |
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195 | |
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196 | if( status & GNUTLS_CERT_SIGNER_NOT_CA ) |
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197 | verifyret |= VERIFY_CERT_SIGNER_NOT_CA; |
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198 | |
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199 | if( status & GNUTLS_CERT_INSECURE_ALGORITHM ) |
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200 | verifyret |= VERIFY_CERT_INSECURE_ALGORITHM; |
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201 | |
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202 | #ifdef GNUTLS_CERT_NOT_ACTIVATED |
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203 | /* Amusingly, the GnuTLS function used above didn't check for expiry |
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204 | until GnuTLS 2.8 or so. (See CVE-2009-1417) */ |
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205 | if( status & GNUTLS_CERT_NOT_ACTIVATED ) |
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206 | verifyret |= VERIFY_CERT_NOT_ACTIVATED; |
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207 | |
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208 | if( status & GNUTLS_CERT_EXPIRED ) |
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209 | verifyret |= VERIFY_CERT_EXPIRED; |
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210 | #endif |
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211 | |
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212 | if( gnutls_certificate_type_get( session ) != GNUTLS_CRT_X509 || gnutls_x509_crt_init( &cert ) < 0 ) |
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213 | return VERIFY_CERT_ERROR; |
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214 | |
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215 | cert_list = gnutls_certificate_get_peers( session, &cert_list_size ); |
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216 | if( cert_list == NULL || gnutls_x509_crt_import( cert, &cert_list[0], GNUTLS_X509_FMT_DER ) < 0 ) |
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217 | return VERIFY_CERT_ERROR; |
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218 | |
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219 | if( !gnutls_x509_crt_check_hostname( cert, conn->hostname ) ) |
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220 | { |
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221 | verifyret |= VERIFY_CERT_INVALID; |
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222 | verifyret |= VERIFY_CERT_WRONG_HOSTNAME; |
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223 | } |
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224 | |
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225 | gnutls_x509_crt_deinit( cert ); |
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226 | |
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227 | return verifyret; |
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228 | } |
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229 | |
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230 | struct ssl_session |
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231 | { |
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232 | size_t size; |
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233 | char data[]; |
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234 | }; |
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235 | |
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236 | static void ssl_cache_add( struct scd *conn ) |
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237 | { |
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238 | size_t data_size = 0; |
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239 | struct ssl_session *data; |
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240 | char *hostname; |
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241 | |
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242 | if( !conn->hostname || |
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243 | gnutls_session_get_data( conn->session, NULL, &data_size ) != 0 ) |
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244 | return; |
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245 | |
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246 | data = g_malloc( sizeof( struct ssl_session ) + data_size ); |
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247 | if( gnutls_session_get_data( conn->session, data->data, &data_size ) != 0 ) |
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248 | { |
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249 | g_free( data ); |
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250 | return; |
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251 | } |
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252 | |
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253 | hostname = g_strdup( conn->hostname ); |
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254 | g_hash_table_insert( session_cache, hostname, data ); |
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255 | } |
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256 | |
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257 | static void ssl_cache_resume( struct scd *conn ) |
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258 | { |
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259 | struct ssl_session *data; |
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260 | |
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261 | if( conn->hostname && |
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262 | ( data = g_hash_table_lookup( session_cache, conn->hostname ) ) ) |
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263 | { |
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264 | gnutls_session_set_data( conn->session, data->data, data->size ); |
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265 | g_hash_table_remove( session_cache, conn->hostname ); |
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266 | } |
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267 | } |
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268 | |
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269 | char *ssl_verify_strerror( int code ) |
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270 | { |
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271 | GString *ret = g_string_new( "" ); |
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272 | |
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273 | if( code & VERIFY_CERT_REVOKED ) |
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274 | g_string_append( ret, "certificate has been revoked, " ); |
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275 | if( code & VERIFY_CERT_SIGNER_NOT_FOUND ) |
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276 | g_string_append( ret, "certificate hasn't got a known issuer, " ); |
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277 | if( code & VERIFY_CERT_SIGNER_NOT_CA ) |
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278 | g_string_append( ret, "certificate's issuer is not a CA, " ); |
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279 | if( code & VERIFY_CERT_INSECURE_ALGORITHM ) |
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280 | g_string_append( ret, "certificate uses an insecure algorithm, " ); |
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281 | if( code & VERIFY_CERT_NOT_ACTIVATED ) |
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282 | g_string_append( ret, "certificate has not been activated, " ); |
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283 | if( code & VERIFY_CERT_EXPIRED ) |
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284 | g_string_append( ret, "certificate has expired, " ); |
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285 | if( code & VERIFY_CERT_WRONG_HOSTNAME ) |
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286 | g_string_append( ret, "certificate hostname mismatch, " ); |
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287 | |
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288 | if( ret->len == 0 ) |
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289 | { |
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290 | g_string_free( ret, TRUE ); |
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291 | return NULL; |
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292 | } |
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293 | else |
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294 | { |
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295 | g_string_truncate( ret, ret->len - 2 ); |
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296 | return g_string_free( ret, FALSE ); |
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297 | } |
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298 | } |
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299 | |
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300 | static gboolean ssl_connected( gpointer data, gint source, b_input_condition cond ) |
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301 | { |
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302 | struct scd *conn = data; |
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303 | |
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304 | if( source == -1 ) |
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305 | { |
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306 | conn->func( conn->data, 0, NULL, cond ); |
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307 | g_free( conn ); |
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308 | return FALSE; |
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309 | } |
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310 | |
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311 | ssl_init(); |
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312 | |
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313 | gnutls_init( &conn->session, GNUTLS_CLIENT ); |
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314 | gnutls_session_set_ptr( conn->session, (void *) conn ); |
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315 | #if GNUTLS_VERSION_NUMBER < 0x020c00 |
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316 | gnutls_transport_set_lowat( conn->session, 0 ); |
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317 | #endif |
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318 | gnutls_set_default_priority( conn->session ); |
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319 | gnutls_credentials_set( conn->session, GNUTLS_CRD_CERTIFICATE, xcred ); |
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320 | if( conn->hostname && !isdigit( conn->hostname[0] ) ) |
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321 | gnutls_server_name_set( conn->session, GNUTLS_NAME_DNS, |
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322 | conn->hostname, strlen( conn->hostname ) ); |
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323 | |
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324 | sock_make_nonblocking( conn->fd ); |
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325 | gnutls_transport_set_ptr( conn->session, (gnutls_transport_ptr_t) GNUTLS_STUPID_CAST conn->fd ); |
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326 | |
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327 | ssl_cache_resume( conn ); |
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328 | |
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329 | return ssl_handshake( data, source, cond ); |
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330 | } |
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331 | |
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332 | static gboolean ssl_handshake( gpointer data, gint source, b_input_condition cond ) |
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333 | { |
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334 | struct scd *conn = data; |
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335 | int st, stver; |
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336 | |
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337 | if( ( st = gnutls_handshake( conn->session ) ) < 0 ) |
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338 | { |
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339 | if( st == GNUTLS_E_AGAIN || st == GNUTLS_E_INTERRUPTED ) |
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340 | { |
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341 | conn->inpa = b_input_add( conn->fd, ssl_getdirection( conn ), |
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342 | ssl_handshake, data ); |
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343 | } |
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344 | else |
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345 | { |
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346 | conn->func( conn->data, 0, NULL, cond ); |
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347 | |
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348 | gnutls_deinit( conn->session ); |
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349 | closesocket( conn->fd ); |
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350 | |
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351 | g_free( conn ); |
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352 | } |
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353 | } |
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354 | else |
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355 | { |
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356 | if( conn->verify && ( stver = verify_certificate_callback( conn->session ) ) != 0 ) |
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357 | { |
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358 | conn->func( conn->data, stver, NULL, cond ); |
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359 | |
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360 | gnutls_deinit( conn->session ); |
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361 | closesocket( conn->fd ); |
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362 | |
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363 | g_free( conn ); |
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364 | } |
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365 | else |
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366 | { |
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367 | /* For now we can't handle non-blocking perfectly everywhere... */ |
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368 | sock_make_blocking( conn->fd ); |
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369 | |
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370 | ssl_cache_add( conn ); |
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371 | conn->established = TRUE; |
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372 | conn->func( conn->data, 0, conn, cond ); |
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373 | } |
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374 | } |
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375 | |
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376 | return FALSE; |
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377 | } |
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378 | |
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379 | int ssl_read( void *conn, char *buf, int len ) |
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380 | { |
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381 | int st; |
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382 | |
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383 | if( !((struct scd*)conn)->established ) |
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384 | { |
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385 | ssl_errno = SSL_NOHANDSHAKE; |
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386 | return -1; |
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387 | } |
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388 | |
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389 | st = gnutls_record_recv( ((struct scd*)conn)->session, buf, len ); |
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390 | |
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391 | ssl_errno = SSL_OK; |
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392 | if( st == GNUTLS_E_AGAIN || st == GNUTLS_E_INTERRUPTED ) |
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393 | ssl_errno = SSL_AGAIN; |
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394 | |
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395 | if( SSLDEBUG && getenv( "BITLBEE_DEBUG" ) && st > 0 ) len = write( 2, buf, st ); |
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396 | |
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397 | return st; |
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398 | } |
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399 | |
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400 | int ssl_write( void *conn, const char *buf, int len ) |
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401 | { |
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402 | int st; |
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403 | |
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404 | if( !((struct scd*)conn)->established ) |
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405 | { |
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406 | ssl_errno = SSL_NOHANDSHAKE; |
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407 | return -1; |
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408 | } |
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409 | |
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410 | st = gnutls_record_send( ((struct scd*)conn)->session, buf, len ); |
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411 | |
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412 | ssl_errno = SSL_OK; |
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413 | if( st == GNUTLS_E_AGAIN || st == GNUTLS_E_INTERRUPTED ) |
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414 | ssl_errno = SSL_AGAIN; |
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415 | |
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416 | if( SSLDEBUG && getenv( "BITLBEE_DEBUG" ) && st > 0 ) len = write( 2, buf, st ); |
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417 | |
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418 | return st; |
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419 | } |
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420 | |
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421 | int ssl_pending( void *conn ) |
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422 | { |
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423 | if( conn == NULL ) |
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424 | return 0; |
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425 | |
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426 | if( !((struct scd*)conn)->established ) |
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427 | { |
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428 | ssl_errno = SSL_NOHANDSHAKE; |
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429 | return 0; |
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430 | } |
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431 | |
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432 | #if GNUTLS_VERSION_NUMBER >= 0x03000d && GNUTLS_VERSION_NUMBER <= 0x030012 |
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433 | if( ssl_errno == SSL_AGAIN ) |
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434 | return 0; |
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435 | #endif |
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436 | |
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437 | return gnutls_record_check_pending( ((struct scd*)conn)->session ) != 0; |
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438 | } |
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439 | |
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440 | void ssl_disconnect( void *conn_ ) |
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441 | { |
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442 | struct scd *conn = conn_; |
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443 | |
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444 | if( conn->inpa != -1 ) |
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445 | b_event_remove( conn->inpa ); |
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446 | |
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447 | if( conn->established ) |
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448 | gnutls_bye( conn->session, GNUTLS_SHUT_WR ); |
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449 | |
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450 | closesocket( conn->fd ); |
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451 | |
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452 | if( conn->session ) |
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453 | gnutls_deinit( conn->session ); |
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454 | g_free( conn->hostname ); |
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455 | g_free( conn ); |
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456 | } |
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457 | |
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458 | int ssl_getfd( void *conn ) |
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459 | { |
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460 | return( ((struct scd*)conn)->fd ); |
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461 | } |
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462 | |
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463 | b_input_condition ssl_getdirection( void *conn ) |
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464 | { |
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465 | return( gnutls_record_get_direction( ((struct scd*)conn)->session ) ? |
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466 | B_EV_IO_WRITE : B_EV_IO_READ ); |
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467 | } |
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468 | |
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469 | size_t ssl_des3_encrypt( const unsigned char *key, size_t key_len, const unsigned char *input, |
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470 | size_t input_len, const unsigned char *iv, unsigned char **res ) |
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471 | { |
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472 | gcry_cipher_hd_t gcr; |
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473 | gcry_error_t st; |
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474 | |
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475 | ssl_init(); |
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476 | |
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477 | *res = g_malloc( input_len ); |
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478 | st = gcry_cipher_open( &gcr, GCRY_CIPHER_3DES, GCRY_CIPHER_MODE_CBC, 0 ) || |
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479 | gcry_cipher_setkey( gcr, key, key_len ) || |
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480 | gcry_cipher_setiv( gcr, iv, 8 ) || |
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481 | gcry_cipher_encrypt( gcr, *res, input_len, input, input_len ); |
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482 | |
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483 | gcry_cipher_close( gcr ); |
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484 | |
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485 | if( st == 0 ) |
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486 | return input_len; |
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487 | |
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488 | g_free( *res ); |
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489 | return 0; |
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490 | } |
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