1 | /*
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2 | * Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
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3 | *
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4 | * Licensed under the OpenSSL license (the "License"). You may not use
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5 | * this file except in compliance with the License. You can obtain a copy
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6 | * in the file LICENSE in the source distribution or at
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7 | * https://www.openssl.org/source/license.html
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8 | */
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9 |
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10 | #include <stdio.h>
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11 | #define USE_SOCKETS
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12 | #include <openssl/objects.h>
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13 | #include <openssl/rand.h>
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14 | #include "ssl_locl.h"
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15 |
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16 | #if defined(OPENSSL_SYS_VMS)
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17 | # include <sys/timeb.h>
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18 | #elif defined(OPENSSL_SYS_VXWORKS)
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19 | # include <sys/times.h>
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20 | #elif !defined(OPENSSL_SYS_WIN32)
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21 | # include <sys/time.h>
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22 | #endif
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23 |
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24 | static void get_current_time(struct timeval *t);
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25 | static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
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26 | static int dtls1_handshake_write(SSL *s);
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27 | static unsigned int dtls1_link_min_mtu(void);
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28 |
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29 | /* XDTLS: figure out the right values */
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30 | static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
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31 |
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32 | const SSL3_ENC_METHOD DTLSv1_enc_data = {
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33 | tls1_enc,
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34 | tls1_mac,
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35 | tls1_setup_key_block,
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36 | tls1_generate_master_secret,
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37 | tls1_change_cipher_state,
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38 | tls1_final_finish_mac,
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39 | TLS1_FINISH_MAC_LENGTH,
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40 | TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
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41 | TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
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42 | tls1_alert_code,
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43 | tls1_export_keying_material,
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44 | SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
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45 | DTLS1_HM_HEADER_LENGTH,
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46 | dtls1_set_handshake_header,
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47 | dtls1_handshake_write
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48 | };
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49 |
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50 | const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
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51 | tls1_enc,
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52 | tls1_mac,
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53 | tls1_setup_key_block,
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54 | tls1_generate_master_secret,
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55 | tls1_change_cipher_state,
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56 | tls1_final_finish_mac,
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57 | TLS1_FINISH_MAC_LENGTH,
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58 | TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
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59 | TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
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60 | tls1_alert_code,
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61 | tls1_export_keying_material,
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62 | SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
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63 | | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
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64 | DTLS1_HM_HEADER_LENGTH,
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65 | dtls1_set_handshake_header,
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66 | dtls1_handshake_write
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67 | };
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68 |
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69 | long dtls1_default_timeout(void)
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70 | {
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71 | /*
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72 | * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
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73 | * http, the cache would over fill
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74 | */
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75 | return (60 * 60 * 2);
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76 | }
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77 |
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78 | int dtls1_new(SSL *s)
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79 | {
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80 | DTLS1_STATE *d1;
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81 |
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82 | if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
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83 | return 0;
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84 | }
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85 |
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86 | if (!ssl3_new(s))
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87 | return (0);
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88 | if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
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89 | ssl3_free(s);
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90 | return (0);
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91 | }
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92 |
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93 | d1->buffered_messages = pqueue_new();
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94 | d1->sent_messages = pqueue_new();
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95 |
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96 | if (s->server) {
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97 | d1->cookie_len = sizeof(s->d1->cookie);
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98 | }
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99 |
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100 | d1->link_mtu = 0;
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101 | d1->mtu = 0;
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102 |
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103 | if (d1->buffered_messages == NULL || d1->sent_messages == NULL) {
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104 | pqueue_free(d1->buffered_messages);
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105 | pqueue_free(d1->sent_messages);
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106 | OPENSSL_free(d1);
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107 | ssl3_free(s);
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108 | return (0);
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109 | }
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110 |
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111 | s->d1 = d1;
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112 | s->method->ssl_clear(s);
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113 | return (1);
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114 | }
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115 |
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116 | static void dtls1_clear_queues(SSL *s)
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117 | {
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118 | dtls1_clear_received_buffer(s);
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119 | dtls1_clear_sent_buffer(s);
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120 | }
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121 |
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122 | void dtls1_clear_received_buffer(SSL *s)
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123 | {
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124 | pitem *item = NULL;
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125 | hm_fragment *frag = NULL;
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126 |
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127 | while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
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128 | frag = (hm_fragment *)item->data;
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129 | dtls1_hm_fragment_free(frag);
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130 | pitem_free(item);
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131 | }
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132 | }
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133 |
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134 | void dtls1_clear_sent_buffer(SSL *s)
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135 | {
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136 | pitem *item = NULL;
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137 | hm_fragment *frag = NULL;
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138 |
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139 | while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
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140 | frag = (hm_fragment *)item->data;
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141 | dtls1_hm_fragment_free(frag);
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142 | pitem_free(item);
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143 | }
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144 | }
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145 |
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146 |
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147 | void dtls1_free(SSL *s)
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148 | {
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149 | DTLS_RECORD_LAYER_free(&s->rlayer);
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150 |
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151 | ssl3_free(s);
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152 |
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153 | dtls1_clear_queues(s);
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154 |
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155 | pqueue_free(s->d1->buffered_messages);
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156 | pqueue_free(s->d1->sent_messages);
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157 |
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158 | OPENSSL_free(s->d1);
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159 | s->d1 = NULL;
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160 | }
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161 |
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162 | void dtls1_clear(SSL *s)
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163 | {
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164 | pqueue *buffered_messages;
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165 | pqueue *sent_messages;
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166 | unsigned int mtu;
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167 | unsigned int link_mtu;
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168 |
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169 | DTLS_RECORD_LAYER_clear(&s->rlayer);
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170 |
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171 | if (s->d1) {
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172 | buffered_messages = s->d1->buffered_messages;
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173 | sent_messages = s->d1->sent_messages;
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174 | mtu = s->d1->mtu;
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175 | link_mtu = s->d1->link_mtu;
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176 |
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177 | dtls1_clear_queues(s);
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178 |
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179 | memset(s->d1, 0, sizeof(*s->d1));
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180 |
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181 | if (s->server) {
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182 | s->d1->cookie_len = sizeof(s->d1->cookie);
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183 | }
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184 |
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185 | if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
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186 | s->d1->mtu = mtu;
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187 | s->d1->link_mtu = link_mtu;
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188 | }
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189 |
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190 | s->d1->buffered_messages = buffered_messages;
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191 | s->d1->sent_messages = sent_messages;
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192 | }
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193 |
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194 | ssl3_clear(s);
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195 |
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196 | if (s->method->version == DTLS_ANY_VERSION)
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197 | s->version = DTLS_MAX_VERSION;
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198 | #ifndef OPENSSL_NO_DTLS1_METHOD
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199 | else if (s->options & SSL_OP_CISCO_ANYCONNECT)
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200 | s->client_version = s->version = DTLS1_BAD_VER;
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201 | #endif
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202 | else
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203 | s->version = s->method->version;
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204 | }
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205 |
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206 | long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
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207 | {
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208 | int ret = 0;
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209 |
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210 | switch (cmd) {
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211 | case DTLS_CTRL_GET_TIMEOUT:
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212 | if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
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213 | ret = 1;
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214 | }
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215 | break;
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216 | case DTLS_CTRL_HANDLE_TIMEOUT:
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217 | ret = dtls1_handle_timeout(s);
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218 | break;
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219 | case DTLS_CTRL_SET_LINK_MTU:
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220 | if (larg < (long)dtls1_link_min_mtu())
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221 | return 0;
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222 | s->d1->link_mtu = larg;
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223 | return 1;
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224 | case DTLS_CTRL_GET_LINK_MIN_MTU:
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225 | return (long)dtls1_link_min_mtu();
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226 | case SSL_CTRL_SET_MTU:
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227 | /*
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228 | * We may not have a BIO set yet so can't call dtls1_min_mtu()
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229 | * We'll have to make do with dtls1_link_min_mtu() and max overhead
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230 | */
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231 | if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
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232 | return 0;
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233 | s->d1->mtu = larg;
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234 | return larg;
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235 | default:
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236 | ret = ssl3_ctrl(s, cmd, larg, parg);
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237 | break;
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238 | }
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239 | return (ret);
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240 | }
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241 |
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242 | void dtls1_start_timer(SSL *s)
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243 | {
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244 | #ifndef OPENSSL_NO_SCTP
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245 | /* Disable timer for SCTP */
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246 | if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
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247 | memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
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248 | return;
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249 | }
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250 | #endif
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251 |
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252 | /* If timer is not set, initialize duration with 1 second */
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253 | if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
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254 | s->d1->timeout_duration = 1;
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255 | }
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256 |
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257 | /* Set timeout to current time */
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258 | get_current_time(&(s->d1->next_timeout));
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259 |
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260 | /* Add duration to current time */
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261 | s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
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262 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
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263 | &(s->d1->next_timeout));
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264 | }
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265 |
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266 | struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
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267 | {
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268 | struct timeval timenow;
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269 |
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270 | /* If no timeout is set, just return NULL */
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271 | if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
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272 | return NULL;
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273 | }
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274 |
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275 | /* Get current time */
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276 | get_current_time(&timenow);
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277 |
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278 | /* If timer already expired, set remaining time to 0 */
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279 | if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
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280 | (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
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281 | s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
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282 | memset(timeleft, 0, sizeof(*timeleft));
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283 | return timeleft;
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284 | }
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285 |
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286 | /* Calculate time left until timer expires */
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287 | memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
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288 | timeleft->tv_sec -= timenow.tv_sec;
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289 | timeleft->tv_usec -= timenow.tv_usec;
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290 | if (timeleft->tv_usec < 0) {
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291 | timeleft->tv_sec--;
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292 | timeleft->tv_usec += 1000000;
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293 | }
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294 |
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295 | /*
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296 | * If remaining time is less than 15 ms, set it to 0 to prevent issues
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297 | * because of small divergences with socket timeouts.
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298 | */
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299 | if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
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300 | memset(timeleft, 0, sizeof(*timeleft));
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301 | }
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302 |
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303 | return timeleft;
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304 | }
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305 |
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306 | int dtls1_is_timer_expired(SSL *s)
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307 | {
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308 | struct timeval timeleft;
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309 |
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310 | /* Get time left until timeout, return false if no timer running */
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311 | if (dtls1_get_timeout(s, &timeleft) == NULL) {
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312 | return 0;
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313 | }
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314 |
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315 | /* Return false if timer is not expired yet */
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316 | if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
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317 | return 0;
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318 | }
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319 |
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320 | /* Timer expired, so return true */
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321 | return 1;
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322 | }
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323 |
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324 | void dtls1_double_timeout(SSL *s)
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325 | {
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326 | s->d1->timeout_duration *= 2;
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327 | if (s->d1->timeout_duration > 60)
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328 | s->d1->timeout_duration = 60;
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329 | dtls1_start_timer(s);
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330 | }
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331 |
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332 | void dtls1_stop_timer(SSL *s)
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333 | {
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334 | /* Reset everything */
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335 | memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
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336 | memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
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337 | s->d1->timeout_duration = 1;
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338 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
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339 | &(s->d1->next_timeout));
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340 | /* Clear retransmission buffer */
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341 | dtls1_clear_sent_buffer(s);
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342 | }
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343 |
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344 | int dtls1_check_timeout_num(SSL *s)
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345 | {
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346 | unsigned int mtu;
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347 |
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348 | s->d1->timeout.num_alerts++;
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349 |
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350 | /* Reduce MTU after 2 unsuccessful retransmissions */
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351 | if (s->d1->timeout.num_alerts > 2
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352 | && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
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353 | mtu =
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354 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
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355 | if (mtu < s->d1->mtu)
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356 | s->d1->mtu = mtu;
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357 | }
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358 |
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359 | if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
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360 | /* fail the connection, enough alerts have been sent */
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361 | SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
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362 | return -1;
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363 | }
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364 |
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365 | return 0;
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366 | }
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367 |
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368 | int dtls1_handle_timeout(SSL *s)
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369 | {
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370 | /* if no timer is expired, don't do anything */
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371 | if (!dtls1_is_timer_expired(s)) {
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372 | return 0;
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373 | }
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374 |
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375 | dtls1_double_timeout(s);
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376 |
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377 | if (dtls1_check_timeout_num(s) < 0)
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378 | return -1;
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379 |
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380 | s->d1->timeout.read_timeouts++;
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381 | if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
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382 | s->d1->timeout.read_timeouts = 1;
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383 | }
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384 | #ifndef OPENSSL_NO_HEARTBEATS
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385 | if (s->tlsext_hb_pending) {
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386 | s->tlsext_hb_pending = 0;
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387 | return dtls1_heartbeat(s);
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388 | }
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389 | #endif
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390 |
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391 | dtls1_start_timer(s);
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392 | return dtls1_retransmit_buffered_messages(s);
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393 | }
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394 |
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395 | static void get_current_time(struct timeval *t)
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396 | {
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397 | #if defined(_WIN32)
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398 | SYSTEMTIME st;
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399 | union {
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400 | unsigned __int64 ul;
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401 | FILETIME ft;
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402 | } now;
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403 |
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404 | GetSystemTime(&st);
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405 | SystemTimeToFileTime(&st, &now.ft);
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406 | /* re-bias to 1/1/1970 */
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407 | # ifdef __MINGW32__
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408 | now.ul -= 116444736000000000ULL;
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409 | # else
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410 | /* *INDENT-OFF* */
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411 | now.ul -= 116444736000000000UI64;
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412 | /* *INDENT-ON* */
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413 | # endif
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414 | t->tv_sec = (long)(now.ul / 10000000);
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415 | t->tv_usec = ((int)(now.ul % 10000000)) / 10;
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416 | #elif defined(OPENSSL_SYS_VMS)
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417 | struct timeb tb;
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418 | ftime(&tb);
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419 | t->tv_sec = (long)tb.time;
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420 | t->tv_usec = (long)tb.millitm * 1000;
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421 | #else
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422 | gettimeofday(t, NULL);
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423 | #endif
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424 | }
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425 |
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426 | #define LISTEN_SUCCESS 2
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427 | #define LISTEN_SEND_VERIFY_REQUEST 1
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428 |
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429 | #ifndef OPENSSL_NO_SOCK
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430 | int DTLSv1_listen(SSL *s, BIO_ADDR *client)
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431 | {
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432 | int next, n, ret = 0, clearpkt = 0;
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433 | unsigned char cookie[DTLS1_COOKIE_LENGTH];
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434 | unsigned char seq[SEQ_NUM_SIZE];
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435 | const unsigned char *data;
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436 | unsigned char *p, *buf;
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437 | unsigned long reclen, fragoff, fraglen, msglen;
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438 | unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
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439 | BIO *rbio, *wbio;
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440 | BUF_MEM *bufm;
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441 | BIO_ADDR *tmpclient = NULL;
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442 | PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
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443 |
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444 | if (s->handshake_func == NULL) {
|
---|
445 | /* Not properly initialized yet */
|
---|
446 | SSL_set_accept_state(s);
|
---|
447 | }
|
---|
448 |
|
---|
449 | /* Ensure there is no state left over from a previous invocation */
|
---|
450 | if (!SSL_clear(s))
|
---|
451 | return -1;
|
---|
452 |
|
---|
453 | ERR_clear_error();
|
---|
454 |
|
---|
455 | rbio = SSL_get_rbio(s);
|
---|
456 | wbio = SSL_get_wbio(s);
|
---|
457 |
|
---|
458 | if (!rbio || !wbio) {
|
---|
459 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET);
|
---|
460 | return -1;
|
---|
461 | }
|
---|
462 |
|
---|
463 | /*
|
---|
464 | * We only peek at incoming ClientHello's until we're sure we are going to
|
---|
465 | * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
|
---|
466 | * cookie then we leave it in the BIO for accept to handle.
|
---|
467 | */
|
---|
468 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
|
---|
469 |
|
---|
470 | /*
|
---|
471 | * Note: This check deliberately excludes DTLS1_BAD_VER because that version
|
---|
472 | * requires the MAC to be calculated *including* the first ClientHello
|
---|
473 | * (without the cookie). Since DTLSv1_listen is stateless that cannot be
|
---|
474 | * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
|
---|
475 | * SSL_accept)
|
---|
476 | */
|
---|
477 | if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
|
---|
478 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
|
---|
479 | return -1;
|
---|
480 | }
|
---|
481 |
|
---|
482 | if (s->init_buf == NULL) {
|
---|
483 | if ((bufm = BUF_MEM_new()) == NULL) {
|
---|
484 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
|
---|
485 | return -1;
|
---|
486 | }
|
---|
487 |
|
---|
488 | if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
|
---|
489 | BUF_MEM_free(bufm);
|
---|
490 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
|
---|
491 | return -1;
|
---|
492 | }
|
---|
493 | s->init_buf = bufm;
|
---|
494 | }
|
---|
495 | buf = (unsigned char *)s->init_buf->data;
|
---|
496 |
|
---|
497 | do {
|
---|
498 | /* Get a packet */
|
---|
499 |
|
---|
500 | clear_sys_error();
|
---|
501 | /*
|
---|
502 | * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
|
---|
503 | * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
|
---|
504 | * the record header as well, but we do here. We've set up init_buf to
|
---|
505 | * be the standard size for simplicity. In practice we shouldn't ever
|
---|
506 | * receive a ClientHello as long as this. If we do it will get dropped
|
---|
507 | * in the record length check below.
|
---|
508 | */
|
---|
509 | n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
|
---|
510 |
|
---|
511 | if (n <= 0) {
|
---|
512 | if (BIO_should_retry(rbio)) {
|
---|
513 | /* Non-blocking IO */
|
---|
514 | goto end;
|
---|
515 | }
|
---|
516 | return -1;
|
---|
517 | }
|
---|
518 |
|
---|
519 | /* If we hit any problems we need to clear this packet from the BIO */
|
---|
520 | clearpkt = 1;
|
---|
521 |
|
---|
522 | if (!PACKET_buf_init(&pkt, buf, n)) {
|
---|
523 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
|
---|
524 | return -1;
|
---|
525 | }
|
---|
526 |
|
---|
527 | /*
|
---|
528 | * Parse the received record. If there are any problems with it we just
|
---|
529 | * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
|
---|
530 | * resilient in the face of invalid records (e.g., invalid formatting,
|
---|
531 | * length, MAC, etc.). In general, invalid records SHOULD be silently
|
---|
532 | * discarded, thus preserving the association; however, an error MAY be
|
---|
533 | * logged for diagnostic purposes."
|
---|
534 | */
|
---|
535 |
|
---|
536 | /* this packet contained a partial record, dump it */
|
---|
537 | if (n < DTLS1_RT_HEADER_LENGTH) {
|
---|
538 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL);
|
---|
539 | goto end;
|
---|
540 | }
|
---|
541 |
|
---|
542 | if (s->msg_callback)
|
---|
543 | s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
|
---|
544 | DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
|
---|
545 |
|
---|
546 | /* Get the record header */
|
---|
547 | if (!PACKET_get_1(&pkt, &rectype)
|
---|
548 | || !PACKET_get_1(&pkt, &versmajor)) {
|
---|
549 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
|
---|
550 | goto end;
|
---|
551 | }
|
---|
552 |
|
---|
553 | if (rectype != SSL3_RT_HANDSHAKE) {
|
---|
554 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
|
---|
555 | goto end;
|
---|
556 | }
|
---|
557 |
|
---|
558 | /*
|
---|
559 | * Check record version number. We only check that the major version is
|
---|
560 | * the same.
|
---|
561 | */
|
---|
562 | if (versmajor != DTLS1_VERSION_MAJOR) {
|
---|
563 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
|
---|
564 | goto end;
|
---|
565 | }
|
---|
566 |
|
---|
567 | if (!PACKET_forward(&pkt, 1)
|
---|
568 | /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
|
---|
569 | || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
|
---|
570 | || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
|
---|
571 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
|
---|
572 | goto end;
|
---|
573 | }
|
---|
574 | /*
|
---|
575 | * We allow data remaining at the end of the packet because there could
|
---|
576 | * be a second record (but we ignore it)
|
---|
577 | */
|
---|
578 |
|
---|
579 | /* This is an initial ClientHello so the epoch has to be 0 */
|
---|
580 | if (seq[0] != 0 || seq[1] != 0) {
|
---|
581 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
|
---|
582 | goto end;
|
---|
583 | }
|
---|
584 |
|
---|
585 | /* Get a pointer to the raw message for the later callback */
|
---|
586 | data = PACKET_data(&msgpkt);
|
---|
587 |
|
---|
588 | /* Finished processing the record header, now process the message */
|
---|
589 | if (!PACKET_get_1(&msgpkt, &msgtype)
|
---|
590 | || !PACKET_get_net_3(&msgpkt, &msglen)
|
---|
591 | || !PACKET_get_net_2(&msgpkt, &msgseq)
|
---|
592 | || !PACKET_get_net_3(&msgpkt, &fragoff)
|
---|
593 | || !PACKET_get_net_3(&msgpkt, &fraglen)
|
---|
594 | || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
|
---|
595 | || PACKET_remaining(&msgpkt) != 0) {
|
---|
596 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
|
---|
597 | goto end;
|
---|
598 | }
|
---|
599 |
|
---|
600 | if (msgtype != SSL3_MT_CLIENT_HELLO) {
|
---|
601 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
|
---|
602 | goto end;
|
---|
603 | }
|
---|
604 |
|
---|
605 | /* Message sequence number can only be 0 or 1 */
|
---|
606 | if (msgseq > 2) {
|
---|
607 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
|
---|
608 | goto end;
|
---|
609 | }
|
---|
610 |
|
---|
611 | /*
|
---|
612 | * We don't support fragment reassembly for ClientHellos whilst
|
---|
613 | * listening because that would require server side state (which is
|
---|
614 | * against the whole point of the ClientHello/HelloVerifyRequest
|
---|
615 | * mechanism). Instead we only look at the first ClientHello fragment
|
---|
616 | * and require that the cookie must be contained within it.
|
---|
617 | */
|
---|
618 | if (fragoff != 0 || fraglen > msglen) {
|
---|
619 | /* Non initial ClientHello fragment (or bad fragment) */
|
---|
620 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
|
---|
621 | goto end;
|
---|
622 | }
|
---|
623 |
|
---|
624 | if (s->msg_callback)
|
---|
625 | s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
|
---|
626 | fraglen + DTLS1_HM_HEADER_LENGTH, s,
|
---|
627 | s->msg_callback_arg);
|
---|
628 |
|
---|
629 | if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
|
---|
630 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
|
---|
631 | goto end;
|
---|
632 | }
|
---|
633 |
|
---|
634 | /*
|
---|
635 | * Verify client version is supported
|
---|
636 | */
|
---|
637 | if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
|
---|
638 | s->method->version != DTLS_ANY_VERSION) {
|
---|
639 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
|
---|
640 | goto end;
|
---|
641 | }
|
---|
642 |
|
---|
643 | if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
|
---|
644 | || !PACKET_get_length_prefixed_1(&msgpayload, &session)
|
---|
645 | || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
|
---|
646 | /*
|
---|
647 | * Could be malformed or the cookie does not fit within the initial
|
---|
648 | * ClientHello fragment. Either way we can't handle it.
|
---|
649 | */
|
---|
650 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
|
---|
651 | goto end;
|
---|
652 | }
|
---|
653 |
|
---|
654 | /*
|
---|
655 | * Check if we have a cookie or not. If not we need to send a
|
---|
656 | * HelloVerifyRequest.
|
---|
657 | */
|
---|
658 | if (PACKET_remaining(&cookiepkt) == 0) {
|
---|
659 | next = LISTEN_SEND_VERIFY_REQUEST;
|
---|
660 | } else {
|
---|
661 | /*
|
---|
662 | * We have a cookie, so lets check it.
|
---|
663 | */
|
---|
664 | if (s->ctx->app_verify_cookie_cb == NULL) {
|
---|
665 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
|
---|
666 | /* This is fatal */
|
---|
667 | return -1;
|
---|
668 | }
|
---|
669 | if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
|
---|
670 | PACKET_remaining(&cookiepkt)) ==
|
---|
671 | 0) {
|
---|
672 | /*
|
---|
673 | * We treat invalid cookies in the same was as no cookie as
|
---|
674 | * per RFC6347
|
---|
675 | */
|
---|
676 | next = LISTEN_SEND_VERIFY_REQUEST;
|
---|
677 | } else {
|
---|
678 | /* Cookie verification succeeded */
|
---|
679 | next = LISTEN_SUCCESS;
|
---|
680 | }
|
---|
681 | }
|
---|
682 |
|
---|
683 | if (next == LISTEN_SEND_VERIFY_REQUEST) {
|
---|
684 | /*
|
---|
685 | * There was no cookie in the ClientHello so we need to send a
|
---|
686 | * HelloVerifyRequest. If this fails we do not worry about trying
|
---|
687 | * to resend, we just drop it.
|
---|
688 | */
|
---|
689 |
|
---|
690 | /*
|
---|
691 | * Dump the read packet, we don't need it any more. Ignore return
|
---|
692 | * value
|
---|
693 | */
|
---|
694 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
|
---|
695 | BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
|
---|
696 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
|
---|
697 |
|
---|
698 | /* Generate the cookie */
|
---|
699 | if (s->ctx->app_gen_cookie_cb == NULL ||
|
---|
700 | s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
|
---|
701 | cookielen > 255) {
|
---|
702 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
|
---|
703 | /* This is fatal */
|
---|
704 | return -1;
|
---|
705 | }
|
---|
706 |
|
---|
707 | p = &buf[DTLS1_RT_HEADER_LENGTH];
|
---|
708 | msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
|
---|
709 | cookie, cookielen);
|
---|
710 |
|
---|
711 | *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
|
---|
712 |
|
---|
713 | /* Message length */
|
---|
714 | l2n3(msglen, p);
|
---|
715 |
|
---|
716 | /* Message sequence number is always 0 for a HelloVerifyRequest */
|
---|
717 | s2n(0, p);
|
---|
718 |
|
---|
719 | /*
|
---|
720 | * We never fragment a HelloVerifyRequest, so fragment offset is 0
|
---|
721 | * and fragment length is message length
|
---|
722 | */
|
---|
723 | l2n3(0, p);
|
---|
724 | l2n3(msglen, p);
|
---|
725 |
|
---|
726 | /* Set reclen equal to length of whole handshake message */
|
---|
727 | reclen = msglen + DTLS1_HM_HEADER_LENGTH;
|
---|
728 |
|
---|
729 | /* Add the record header */
|
---|
730 | p = buf;
|
---|
731 |
|
---|
732 | *(p++) = SSL3_RT_HANDSHAKE;
|
---|
733 | /*
|
---|
734 | * Special case: for hello verify request, client version 1.0 and we
|
---|
735 | * haven't decided which version to use yet send back using version
|
---|
736 | * 1.0 header: otherwise some clients will ignore it.
|
---|
737 | */
|
---|
738 | if (s->method->version == DTLS_ANY_VERSION) {
|
---|
739 | *(p++) = DTLS1_VERSION >> 8;
|
---|
740 | *(p++) = DTLS1_VERSION & 0xff;
|
---|
741 | } else {
|
---|
742 | *(p++) = s->version >> 8;
|
---|
743 | *(p++) = s->version & 0xff;
|
---|
744 | }
|
---|
745 |
|
---|
746 | /*
|
---|
747 | * Record sequence number is always the same as in the received
|
---|
748 | * ClientHello
|
---|
749 | */
|
---|
750 | memcpy(p, seq, SEQ_NUM_SIZE);
|
---|
751 | p += SEQ_NUM_SIZE;
|
---|
752 |
|
---|
753 | /* Length */
|
---|
754 | s2n(reclen, p);
|
---|
755 |
|
---|
756 | /*
|
---|
757 | * Set reclen equal to length of whole record including record
|
---|
758 | * header
|
---|
759 | */
|
---|
760 | reclen += DTLS1_RT_HEADER_LENGTH;
|
---|
761 |
|
---|
762 | if (s->msg_callback)
|
---|
763 | s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
|
---|
764 | DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
|
---|
765 |
|
---|
766 | if ((tmpclient = BIO_ADDR_new()) == NULL) {
|
---|
767 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
|
---|
768 | goto end;
|
---|
769 | }
|
---|
770 |
|
---|
771 | /*
|
---|
772 | * This is unnecessary if rbio and wbio are one and the same - but
|
---|
773 | * maybe they're not. We ignore errors here - some BIOs do not
|
---|
774 | * support this.
|
---|
775 | */
|
---|
776 | if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
|
---|
777 | (void)BIO_dgram_set_peer(wbio, tmpclient);
|
---|
778 | }
|
---|
779 | BIO_ADDR_free(tmpclient);
|
---|
780 | tmpclient = NULL;
|
---|
781 |
|
---|
782 | if (BIO_write(wbio, buf, reclen) < (int)reclen) {
|
---|
783 | if (BIO_should_retry(wbio)) {
|
---|
784 | /*
|
---|
785 | * Non-blocking IO...but we're stateless, so we're just
|
---|
786 | * going to drop this packet.
|
---|
787 | */
|
---|
788 | goto end;
|
---|
789 | }
|
---|
790 | return -1;
|
---|
791 | }
|
---|
792 |
|
---|
793 | if (BIO_flush(wbio) <= 0) {
|
---|
794 | if (BIO_should_retry(wbio)) {
|
---|
795 | /*
|
---|
796 | * Non-blocking IO...but we're stateless, so we're just
|
---|
797 | * going to drop this packet.
|
---|
798 | */
|
---|
799 | goto end;
|
---|
800 | }
|
---|
801 | return -1;
|
---|
802 | }
|
---|
803 | }
|
---|
804 | } while (next != LISTEN_SUCCESS);
|
---|
805 |
|
---|
806 | /*
|
---|
807 | * Set expected sequence numbers to continue the handshake.
|
---|
808 | */
|
---|
809 | s->d1->handshake_read_seq = 1;
|
---|
810 | s->d1->handshake_write_seq = 1;
|
---|
811 | s->d1->next_handshake_write_seq = 1;
|
---|
812 | DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
|
---|
813 |
|
---|
814 | /*
|
---|
815 | * We are doing cookie exchange, so make sure we set that option in the
|
---|
816 | * SSL object
|
---|
817 | */
|
---|
818 | SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
|
---|
819 |
|
---|
820 | /*
|
---|
821 | * Tell the state machine that we've done the initial hello verify
|
---|
822 | * exchange
|
---|
823 | */
|
---|
824 | ossl_statem_set_hello_verify_done(s);
|
---|
825 |
|
---|
826 | /*
|
---|
827 | * Some BIOs may not support this. If we fail we clear the client address
|
---|
828 | */
|
---|
829 | if (BIO_dgram_get_peer(rbio, client) <= 0)
|
---|
830 | BIO_ADDR_clear(client);
|
---|
831 |
|
---|
832 | ret = 1;
|
---|
833 | clearpkt = 0;
|
---|
834 | end:
|
---|
835 | BIO_ADDR_free(tmpclient);
|
---|
836 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
|
---|
837 | if (clearpkt) {
|
---|
838 | /* Dump this packet. Ignore return value */
|
---|
839 | BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
|
---|
840 | }
|
---|
841 | return ret;
|
---|
842 | }
|
---|
843 | #endif
|
---|
844 |
|
---|
845 | static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
|
---|
846 | {
|
---|
847 | dtls1_set_message_header(s, htype, len, 0, len);
|
---|
848 | s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
|
---|
849 | s->init_off = 0;
|
---|
850 | /* Buffer the message to handle re-xmits */
|
---|
851 |
|
---|
852 | if (!dtls1_buffer_message(s, 0))
|
---|
853 | return 0;
|
---|
854 |
|
---|
855 | return 1;
|
---|
856 | }
|
---|
857 |
|
---|
858 | static int dtls1_handshake_write(SSL *s)
|
---|
859 | {
|
---|
860 | return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
|
---|
861 | }
|
---|
862 |
|
---|
863 | #ifndef OPENSSL_NO_HEARTBEATS
|
---|
864 |
|
---|
865 | # define HEARTBEAT_SIZE(payload, padding) ( \
|
---|
866 | 1 /* heartbeat type */ + \
|
---|
867 | 2 /* heartbeat length */ + \
|
---|
868 | (payload) + (padding))
|
---|
869 |
|
---|
870 | # define HEARTBEAT_SIZE_STD(payload) HEARTBEAT_SIZE(payload, 16)
|
---|
871 |
|
---|
872 | int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
|
---|
873 | {
|
---|
874 | unsigned char *pl;
|
---|
875 | unsigned short hbtype;
|
---|
876 | unsigned int payload;
|
---|
877 | unsigned int padding = 16; /* Use minimum padding */
|
---|
878 |
|
---|
879 | if (s->msg_callback)
|
---|
880 | s->msg_callback(0, s->version, DTLS1_RT_HEARTBEAT,
|
---|
881 | p, length, s, s->msg_callback_arg);
|
---|
882 |
|
---|
883 | /* Read type and payload length */
|
---|
884 | if (HEARTBEAT_SIZE_STD(0) > length)
|
---|
885 | return 0; /* silently discard */
|
---|
886 | if (length > SSL3_RT_MAX_PLAIN_LENGTH)
|
---|
887 | return 0; /* silently discard per RFC 6520 sec. 4 */
|
---|
888 |
|
---|
889 | hbtype = *p++;
|
---|
890 | n2s(p, payload);
|
---|
891 | if (HEARTBEAT_SIZE_STD(payload) > length)
|
---|
892 | return 0; /* silently discard per RFC 6520 sec. 4 */
|
---|
893 | pl = p;
|
---|
894 |
|
---|
895 | if (hbtype == TLS1_HB_REQUEST) {
|
---|
896 | unsigned char *buffer, *bp;
|
---|
897 | unsigned int write_length = HEARTBEAT_SIZE(payload, padding);
|
---|
898 | int r;
|
---|
899 |
|
---|
900 | if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
|
---|
901 | return 0;
|
---|
902 |
|
---|
903 | /* Allocate memory for the response. */
|
---|
904 | buffer = OPENSSL_malloc(write_length);
|
---|
905 | if (buffer == NULL)
|
---|
906 | return -1;
|
---|
907 | bp = buffer;
|
---|
908 |
|
---|
909 | /* Enter response type, length and copy payload */
|
---|
910 | *bp++ = TLS1_HB_RESPONSE;
|
---|
911 | s2n(payload, bp);
|
---|
912 | memcpy(bp, pl, payload);
|
---|
913 | bp += payload;
|
---|
914 | /* Random padding */
|
---|
915 | if (RAND_bytes(bp, padding) <= 0) {
|
---|
916 | OPENSSL_free(buffer);
|
---|
917 | return -1;
|
---|
918 | }
|
---|
919 |
|
---|
920 | r = dtls1_write_bytes(s, DTLS1_RT_HEARTBEAT, buffer, write_length);
|
---|
921 |
|
---|
922 | if (r >= 0 && s->msg_callback)
|
---|
923 | s->msg_callback(1, s->version, DTLS1_RT_HEARTBEAT,
|
---|
924 | buffer, write_length, s, s->msg_callback_arg);
|
---|
925 |
|
---|
926 | OPENSSL_free(buffer);
|
---|
927 |
|
---|
928 | if (r < 0)
|
---|
929 | return r;
|
---|
930 | } else if (hbtype == TLS1_HB_RESPONSE) {
|
---|
931 | unsigned int seq;
|
---|
932 |
|
---|
933 | /*
|
---|
934 | * We only send sequence numbers (2 bytes unsigned int), and 16
|
---|
935 | * random bytes, so we just try to read the sequence number
|
---|
936 | */
|
---|
937 | n2s(pl, seq);
|
---|
938 |
|
---|
939 | if (payload == 18 && seq == s->tlsext_hb_seq) {
|
---|
940 | dtls1_stop_timer(s);
|
---|
941 | s->tlsext_hb_seq++;
|
---|
942 | s->tlsext_hb_pending = 0;
|
---|
943 | }
|
---|
944 | }
|
---|
945 |
|
---|
946 | return 0;
|
---|
947 | }
|
---|
948 |
|
---|
949 | int dtls1_heartbeat(SSL *s)
|
---|
950 | {
|
---|
951 | unsigned char *buf, *p;
|
---|
952 | int ret = -1;
|
---|
953 | unsigned int payload = 18; /* Sequence number + random bytes */
|
---|
954 | unsigned int padding = 16; /* Use minimum padding */
|
---|
955 | unsigned int size;
|
---|
956 |
|
---|
957 | /* Only send if peer supports and accepts HB requests... */
|
---|
958 | if (!(s->tlsext_heartbeat & SSL_DTLSEXT_HB_ENABLED) ||
|
---|
959 | s->tlsext_heartbeat & SSL_DTLSEXT_HB_DONT_SEND_REQUESTS) {
|
---|
960 | SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
|
---|
961 | return -1;
|
---|
962 | }
|
---|
963 |
|
---|
964 | /* ...and there is none in flight yet... */
|
---|
965 | if (s->tlsext_hb_pending) {
|
---|
966 | SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
|
---|
967 | return -1;
|
---|
968 | }
|
---|
969 |
|
---|
970 | /* ...and no handshake in progress. */
|
---|
971 | if (SSL_in_init(s) || ossl_statem_get_in_handshake(s)) {
|
---|
972 | SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
|
---|
973 | return -1;
|
---|
974 | }
|
---|
975 |
|
---|
976 | /*-
|
---|
977 | * Create HeartBeat message, we just use a sequence number
|
---|
978 | * as payload to distinguish different messages and add
|
---|
979 | * some random stuff.
|
---|
980 | */
|
---|
981 | size = HEARTBEAT_SIZE(payload, padding);
|
---|
982 | buf = OPENSSL_malloc(size);
|
---|
983 | if (buf == NULL) {
|
---|
984 | SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
|
---|
985 | return -1;
|
---|
986 | }
|
---|
987 | p = buf;
|
---|
988 | /* Message Type */
|
---|
989 | *p++ = TLS1_HB_REQUEST;
|
---|
990 | /* Payload length (18 bytes here) */
|
---|
991 | s2n(payload, p);
|
---|
992 | /* Sequence number */
|
---|
993 | s2n(s->tlsext_hb_seq, p);
|
---|
994 | /* 16 random bytes */
|
---|
995 | if (RAND_bytes(p, 16) <= 0) {
|
---|
996 | SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
|
---|
997 | goto err;
|
---|
998 | }
|
---|
999 | p += 16;
|
---|
1000 | /* Random padding */
|
---|
1001 | if (RAND_bytes(p, padding) <= 0) {
|
---|
1002 | SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
|
---|
1003 | goto err;
|
---|
1004 | }
|
---|
1005 |
|
---|
1006 | ret = dtls1_write_bytes(s, DTLS1_RT_HEARTBEAT, buf, size);
|
---|
1007 | if (ret >= 0) {
|
---|
1008 | if (s->msg_callback)
|
---|
1009 | s->msg_callback(1, s->version, DTLS1_RT_HEARTBEAT,
|
---|
1010 | buf, size, s, s->msg_callback_arg);
|
---|
1011 |
|
---|
1012 | dtls1_start_timer(s);
|
---|
1013 | s->tlsext_hb_pending = 1;
|
---|
1014 | }
|
---|
1015 |
|
---|
1016 | err:
|
---|
1017 | OPENSSL_free(buf);
|
---|
1018 |
|
---|
1019 | return ret;
|
---|
1020 | }
|
---|
1021 | #endif
|
---|
1022 |
|
---|
1023 | int dtls1_shutdown(SSL *s)
|
---|
1024 | {
|
---|
1025 | int ret;
|
---|
1026 | #ifndef OPENSSL_NO_SCTP
|
---|
1027 | BIO *wbio;
|
---|
1028 |
|
---|
1029 | wbio = SSL_get_wbio(s);
|
---|
1030 | if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
|
---|
1031 | !(s->shutdown & SSL_SENT_SHUTDOWN)) {
|
---|
1032 | ret = BIO_dgram_sctp_wait_for_dry(wbio);
|
---|
1033 | if (ret < 0)
|
---|
1034 | return -1;
|
---|
1035 |
|
---|
1036 | if (ret == 0)
|
---|
1037 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
|
---|
1038 | NULL);
|
---|
1039 | }
|
---|
1040 | #endif
|
---|
1041 | ret = ssl3_shutdown(s);
|
---|
1042 | #ifndef OPENSSL_NO_SCTP
|
---|
1043 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
|
---|
1044 | #endif
|
---|
1045 | return ret;
|
---|
1046 | }
|
---|
1047 |
|
---|
1048 | int dtls1_query_mtu(SSL *s)
|
---|
1049 | {
|
---|
1050 | if (s->d1->link_mtu) {
|
---|
1051 | s->d1->mtu =
|
---|
1052 | s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
|
---|
1053 | s->d1->link_mtu = 0;
|
---|
1054 | }
|
---|
1055 |
|
---|
1056 | /* AHA! Figure out the MTU, and stick to the right size */
|
---|
1057 | if (s->d1->mtu < dtls1_min_mtu(s)) {
|
---|
1058 | if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
|
---|
1059 | s->d1->mtu =
|
---|
1060 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
|
---|
1061 |
|
---|
1062 | /*
|
---|
1063 | * I've seen the kernel return bogus numbers when it doesn't know
|
---|
1064 | * (initial write), so just make sure we have a reasonable number
|
---|
1065 | */
|
---|
1066 | if (s->d1->mtu < dtls1_min_mtu(s)) {
|
---|
1067 | /* Set to min mtu */
|
---|
1068 | s->d1->mtu = dtls1_min_mtu(s);
|
---|
1069 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
|
---|
1070 | s->d1->mtu, NULL);
|
---|
1071 | }
|
---|
1072 | } else
|
---|
1073 | return 0;
|
---|
1074 | }
|
---|
1075 | return 1;
|
---|
1076 | }
|
---|
1077 |
|
---|
1078 | static unsigned int dtls1_link_min_mtu(void)
|
---|
1079 | {
|
---|
1080 | return (g_probable_mtu[(sizeof(g_probable_mtu) /
|
---|
1081 | sizeof(g_probable_mtu[0])) - 1]);
|
---|
1082 | }
|
---|
1083 |
|
---|
1084 | unsigned int dtls1_min_mtu(SSL *s)
|
---|
1085 | {
|
---|
1086 | return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
|
---|
1087 | }
|
---|