1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_crypto.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "gap.h" 53 #include "hci.h" 54 #include "hci_dump.h" 55 #include "l2cap.h" 56 57 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 58 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 59 #endif 60 61 // assert SM Public Key can be sent/received 62 #ifdef ENABLE_LE_SECURE_CONNECTIONS 63 #if HCI_ACL_PAYLOAD_SIZE < 69 64 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 65 #endif 66 #endif 67 68 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 69 #define IS_RESPONDER(role) (role) 70 #else 71 #ifdef ENABLE_LE_CENTRAL 72 // only central - never responder (avoid 'unused variable' warnings) 73 #define IS_RESPONDER(role) (0 && role) 74 #else 75 // only peripheral - always responder (avoid 'unused variable' warnings) 76 #define IS_RESPONDER(role) (1 || role) 77 #endif 78 #endif 79 80 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 81 #define USE_CMAC_ENGINE 82 #endif 83 84 // 85 // SM internal types and globals 86 // 87 88 typedef enum { 89 DKG_W4_WORKING, 90 DKG_CALC_IRK, 91 DKG_CALC_DHK, 92 DKG_READY 93 } derived_key_generation_t; 94 95 typedef enum { 96 RAU_IDLE, 97 RAU_GET_RANDOM, 98 RAU_W4_RANDOM, 99 RAU_GET_ENC, 100 RAU_W4_ENC, 101 RAU_SET_ADDRESS, 102 } random_address_update_t; 103 104 typedef enum { 105 CMAC_IDLE, 106 CMAC_CALC_SUBKEYS, 107 CMAC_W4_SUBKEYS, 108 CMAC_CALC_MI, 109 CMAC_W4_MI, 110 CMAC_CALC_MLAST, 111 CMAC_W4_MLAST 112 } cmac_state_t; 113 114 typedef enum { 115 JUST_WORKS, 116 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 117 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 118 PK_BOTH_INPUT, // Only input on both, both input PK 119 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 120 OOB // OOB available on one (SC) or both sides (legacy) 121 } stk_generation_method_t; 122 123 typedef enum { 124 SM_USER_RESPONSE_IDLE, 125 SM_USER_RESPONSE_PENDING, 126 SM_USER_RESPONSE_CONFIRM, 127 SM_USER_RESPONSE_PASSKEY, 128 SM_USER_RESPONSE_DECLINE 129 } sm_user_response_t; 130 131 typedef enum { 132 SM_AES128_IDLE, 133 SM_AES128_ACTIVE 134 } sm_aes128_state_t; 135 136 typedef enum { 137 ADDRESS_RESOLUTION_IDLE, 138 ADDRESS_RESOLUTION_GENERAL, 139 ADDRESS_RESOLUTION_FOR_CONNECTION, 140 } address_resolution_mode_t; 141 142 typedef enum { 143 ADDRESS_RESOLUTION_SUCEEDED, 144 ADDRESS_RESOLUTION_FAILED, 145 } address_resolution_event_t; 146 147 typedef enum { 148 EC_KEY_GENERATION_IDLE, 149 EC_KEY_GENERATION_ACTIVE, 150 EC_KEY_GENERATION_DONE, 151 } ec_key_generation_state_t; 152 153 typedef enum { 154 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 155 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 156 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 157 } sm_state_var_t; 158 159 typedef enum { 160 SM_SC_OOB_IDLE, 161 SM_SC_OOB_W4_RANDOM, 162 SM_SC_OOB_W2_CALC_CONFIRM, 163 SM_SC_OOB_W4_CONFIRM, 164 } sm_sc_oob_state_t; 165 166 typedef uint8_t sm_key24_t[3]; 167 typedef uint8_t sm_key56_t[7]; 168 typedef uint8_t sm_key256_t[32]; 169 170 // 171 // GLOBAL DATA 172 // 173 174 static uint8_t test_use_fixed_local_csrk; 175 176 #ifdef ENABLE_TESTING_SUPPORT 177 static uint8_t test_pairing_failure; 178 #endif 179 180 // configuration 181 static uint8_t sm_accepted_stk_generation_methods; 182 static uint8_t sm_max_encryption_key_size; 183 static uint8_t sm_min_encryption_key_size; 184 static uint8_t sm_auth_req = 0; 185 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 186 static uint8_t sm_slave_request_security; 187 static uint32_t sm_fixed_passkey_in_display_role; 188 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 189 190 #ifdef ENABLE_LE_SECURE_CONNECTIONS 191 static uint8_t sm_sc_oob_random[16]; 192 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 193 static sm_sc_oob_state_t sm_sc_oob_state; 194 #endif 195 196 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 197 static sm_key_t sm_persistent_er; 198 static sm_key_t sm_persistent_ir; 199 200 // derived from sm_persistent_ir 201 static sm_key_t sm_persistent_dhk; 202 static sm_key_t sm_persistent_irk; 203 static uint8_t sm_persistent_irk_ready = 0; // used for testing 204 static derived_key_generation_t dkg_state; 205 206 // derived from sm_persistent_er 207 // .. 208 209 // random address update 210 static random_address_update_t rau_state; 211 static bd_addr_t sm_random_address; 212 213 #ifdef USE_CMAC_ENGINE 214 // CMAC Calculation: General 215 static btstack_crypto_aes128_cmac_t sm_cmac_request; 216 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 217 static uint8_t sm_cmac_active; 218 static uint8_t sm_cmac_hash[16]; 219 #endif 220 221 // CMAC for ATT Signed Writes 222 #ifdef ENABLE_LE_SIGNED_WRITE 223 static uint16_t sm_cmac_signed_write_message_len; 224 static uint8_t sm_cmac_signed_write_header[3]; 225 static const uint8_t * sm_cmac_signed_write_message; 226 static uint8_t sm_cmac_signed_write_sign_counter[4]; 227 #endif 228 229 // CMAC for Secure Connection functions 230 #ifdef ENABLE_LE_SECURE_CONNECTIONS 231 static sm_connection_t * sm_cmac_connection; 232 static uint8_t sm_cmac_sc_buffer[80]; 233 #endif 234 235 // resolvable private address lookup / CSRK calculation 236 static int sm_address_resolution_test; 237 static int sm_address_resolution_ah_calculation_active; 238 static uint8_t sm_address_resolution_addr_type; 239 static bd_addr_t sm_address_resolution_address; 240 static void * sm_address_resolution_context; 241 static address_resolution_mode_t sm_address_resolution_mode; 242 static btstack_linked_list_t sm_address_resolution_general_queue; 243 244 // aes128 crypto engine. 245 static sm_aes128_state_t sm_aes128_state; 246 247 // crypto 248 static btstack_crypto_random_t sm_crypto_random_request; 249 static btstack_crypto_aes128_t sm_crypto_aes128_request; 250 #ifdef ENABLE_LE_SECURE_CONNECTIONS 251 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 252 static btstack_crypto_random_t sm_crypto_random_oob_request; 253 #endif 254 255 // temp storage for random data 256 static uint8_t sm_random_data[8]; 257 static uint8_t sm_aes128_key[16]; 258 static uint8_t sm_aes128_plaintext[16]; 259 static uint8_t sm_aes128_ciphertext[16]; 260 261 // to receive hci events 262 static btstack_packet_callback_registration_t hci_event_callback_registration; 263 264 /* to dispatch sm event */ 265 static btstack_linked_list_t sm_event_handlers; 266 267 // LE Secure Connections 268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 269 static ec_key_generation_state_t ec_key_generation_state; 270 static uint8_t ec_q[64]; 271 #endif 272 273 // 274 // Volume 3, Part H, Chapter 24 275 // "Security shall be initiated by the Security Manager in the device in the master role. 276 // The device in the slave role shall be the responding device." 277 // -> master := initiator, slave := responder 278 // 279 280 // data needed for security setup 281 typedef struct sm_setup_context { 282 283 btstack_timer_source_t sm_timeout; 284 285 // used in all phases 286 uint8_t sm_pairing_failed_reason; 287 288 // user response, (Phase 1 and/or 2) 289 uint8_t sm_user_response; 290 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 291 292 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 293 int sm_key_distribution_send_set; 294 int sm_key_distribution_received_set; 295 296 // Phase 2 (Pairing over SMP) 297 stk_generation_method_t sm_stk_generation_method; 298 sm_key_t sm_tk; 299 uint8_t sm_have_oob_data; 300 uint8_t sm_use_secure_connections; 301 302 sm_key_t sm_c1_t3_value; // c1 calculation 303 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 304 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 305 sm_key_t sm_local_random; 306 sm_key_t sm_local_confirm; 307 sm_key_t sm_peer_random; 308 sm_key_t sm_peer_confirm; 309 uint8_t sm_m_addr_type; // address and type can be removed 310 uint8_t sm_s_addr_type; // '' 311 bd_addr_t sm_m_address; // '' 312 bd_addr_t sm_s_address; // '' 313 sm_key_t sm_ltk; 314 315 uint8_t sm_state_vars; 316 #ifdef ENABLE_LE_SECURE_CONNECTIONS 317 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 318 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 319 sm_key_t sm_local_nonce; // might be combined with sm_local_random 320 sm_key_t sm_dhkey; 321 sm_key_t sm_peer_dhkey_check; 322 sm_key_t sm_local_dhkey_check; 323 sm_key_t sm_ra; 324 sm_key_t sm_rb; 325 sm_key_t sm_t; // used for f5 and h6 326 sm_key_t sm_mackey; 327 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 328 #endif 329 330 // Phase 3 331 332 // key distribution, we generate 333 uint16_t sm_local_y; 334 uint16_t sm_local_div; 335 uint16_t sm_local_ediv; 336 uint8_t sm_local_rand[8]; 337 sm_key_t sm_local_ltk; 338 sm_key_t sm_local_csrk; 339 sm_key_t sm_local_irk; 340 // sm_local_address/addr_type not needed 341 342 // key distribution, received from peer 343 uint16_t sm_peer_y; 344 uint16_t sm_peer_div; 345 uint16_t sm_peer_ediv; 346 uint8_t sm_peer_rand[8]; 347 sm_key_t sm_peer_ltk; 348 sm_key_t sm_peer_irk; 349 sm_key_t sm_peer_csrk; 350 uint8_t sm_peer_addr_type; 351 bd_addr_t sm_peer_address; 352 353 } sm_setup_context_t; 354 355 // 356 static sm_setup_context_t the_setup; 357 static sm_setup_context_t * setup = &the_setup; 358 359 // active connection - the one for which the_setup is used for 360 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 361 362 // @returns 1 if oob data is available 363 // stores oob data in provided 16 byte buffer if not null 364 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 365 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 366 367 // horizontal: initiator capabilities 368 // vertial: responder capabilities 369 static const stk_generation_method_t stk_generation_method [5] [5] = { 370 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 371 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 372 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 373 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 374 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 375 }; 376 377 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 378 #ifdef ENABLE_LE_SECURE_CONNECTIONS 379 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 380 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 381 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 382 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 383 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 384 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 385 }; 386 #endif 387 388 static void sm_run(void); 389 #ifdef USE_CMAC_ENGINE 390 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 391 #endif 392 static void sm_done_for_handle(hci_con_handle_t con_handle); 393 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 394 static inline int sm_calc_actual_encryption_key_size(int other); 395 static int sm_validate_stk_generation_method(void); 396 static void sm_handle_encryption_result_address_resolution(void *arg); 397 static void sm_handle_encryption_result_dkg_dhk(void *arg); 398 static void sm_handle_encryption_result_dkg_irk(void *arg); 399 static void sm_handle_encryption_result_enc_a(void *arg); 400 static void sm_handle_encryption_result_enc_b(void *arg); 401 static void sm_handle_encryption_result_enc_c(void *arg); 402 static void sm_handle_encryption_result_enc_csrk(void *arg); 403 static void sm_handle_encryption_result_enc_d(void * arg); 404 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 405 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 406 #ifdef ENABLE_LE_PERIPHERAL 407 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 408 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 409 #endif 410 static void sm_handle_encryption_result_enc_stk(void *arg); 411 static void sm_handle_encryption_result_rau(void *arg); 412 static void sm_handle_random_result_ph2_tk(void * arg); 413 static void sm_handle_random_result_rau(void * arg); 414 #ifdef ENABLE_LE_SECURE_CONNECTIONS 415 static void sm_ec_generate_new_key(void); 416 static void sm_handle_random_result_sc_get_random(void * arg); 417 static int sm_passkey_entry(stk_generation_method_t method); 418 #endif 419 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 420 421 static void log_info_hex16(const char * name, uint16_t value){ 422 log_info("%-6s 0x%04x", name, value); 423 } 424 425 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 426 // return packet[0]; 427 // } 428 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 429 return packet[1]; 430 } 431 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 432 return packet[2]; 433 } 434 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 435 return packet[3]; 436 } 437 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 438 return packet[4]; 439 } 440 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 441 return packet[5]; 442 } 443 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 444 return packet[6]; 445 } 446 447 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 448 packet[0] = code; 449 } 450 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 451 packet[1] = io_capability; 452 } 453 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 454 packet[2] = oob_data_flag; 455 } 456 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 457 packet[3] = auth_req; 458 } 459 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 460 packet[4] = max_encryption_key_size; 461 } 462 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 463 packet[5] = initiator_key_distribution; 464 } 465 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 466 packet[6] = responder_key_distribution; 467 } 468 469 // @returns 1 if all bytes are 0 470 static int sm_is_null(uint8_t * data, int size){ 471 int i; 472 for (i=0; i < size ; i++){ 473 if (data[i]) return 0; 474 } 475 return 1; 476 } 477 478 static int sm_is_null_random(uint8_t random[8]){ 479 return sm_is_null(random, 8); 480 } 481 482 static int sm_is_null_key(uint8_t * key){ 483 return sm_is_null(key, 16); 484 } 485 486 // Key utils 487 static void sm_reset_tk(void){ 488 int i; 489 for (i=0;i<16;i++){ 490 setup->sm_tk[i] = 0; 491 } 492 } 493 494 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 495 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 496 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 497 int i; 498 for (i = max_encryption_size ; i < 16 ; i++){ 499 key[15-i] = 0; 500 } 501 } 502 503 // SMP Timeout implementation 504 505 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 506 // the Security Manager Timer shall be reset and started. 507 // 508 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 509 // 510 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 511 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 512 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 513 // established. 514 515 static void sm_timeout_handler(btstack_timer_source_t * timer){ 516 log_info("SM timeout"); 517 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 518 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 519 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 520 sm_done_for_handle(sm_conn->sm_handle); 521 522 // trigger handling of next ready connection 523 sm_run(); 524 } 525 static void sm_timeout_start(sm_connection_t * sm_conn){ 526 btstack_run_loop_remove_timer(&setup->sm_timeout); 527 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 528 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 529 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 530 btstack_run_loop_add_timer(&setup->sm_timeout); 531 } 532 static void sm_timeout_stop(void){ 533 btstack_run_loop_remove_timer(&setup->sm_timeout); 534 } 535 static void sm_timeout_reset(sm_connection_t * sm_conn){ 536 sm_timeout_stop(); 537 sm_timeout_start(sm_conn); 538 } 539 540 // end of sm timeout 541 542 // GAP Random Address updates 543 static gap_random_address_type_t gap_random_adress_type; 544 static btstack_timer_source_t gap_random_address_update_timer; 545 static uint32_t gap_random_adress_update_period; 546 547 static void gap_random_address_trigger(void){ 548 log_info("gap_random_address_trigger"); 549 if (rau_state != RAU_IDLE) return; 550 rau_state = RAU_GET_RANDOM; 551 sm_run(); 552 } 553 554 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 555 UNUSED(timer); 556 557 log_info("GAP Random Address Update due"); 558 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 559 btstack_run_loop_add_timer(&gap_random_address_update_timer); 560 gap_random_address_trigger(); 561 } 562 563 static void gap_random_address_update_start(void){ 564 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 565 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 566 btstack_run_loop_add_timer(&gap_random_address_update_timer); 567 } 568 569 static void gap_random_address_update_stop(void){ 570 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 571 } 572 573 // ah(k,r) helper 574 // r = padding || r 575 // r - 24 bit value 576 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 577 // r'= padding || r 578 memset(r_prime, 0, 16); 579 memcpy(&r_prime[13], r, 3); 580 } 581 582 // d1 helper 583 // d' = padding || r || d 584 // d,r - 16 bit values 585 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 586 // d'= padding || r || d 587 memset(d1_prime, 0, 16); 588 big_endian_store_16(d1_prime, 12, r); 589 big_endian_store_16(d1_prime, 14, d); 590 } 591 592 // dm helper 593 // r’ = padding || r 594 // r - 64 bit value 595 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 596 memset(r_prime, 0, 16); 597 memcpy(&r_prime[8], r, 8); 598 } 599 600 // calculate arguments for first AES128 operation in C1 function 601 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 602 603 // p1 = pres || preq || rat’ || iat’ 604 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 605 // cant octet of pres becomes the most significant octet of p1. 606 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 607 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 608 // p1 is 0x05000800000302070710000001010001." 609 610 sm_key_t p1; 611 reverse_56(pres, &p1[0]); 612 reverse_56(preq, &p1[7]); 613 p1[14] = rat; 614 p1[15] = iat; 615 log_info_key("p1", p1); 616 log_info_key("r", r); 617 618 // t1 = r xor p1 619 int i; 620 for (i=0;i<16;i++){ 621 t1[i] = r[i] ^ p1[i]; 622 } 623 log_info_key("t1", t1); 624 } 625 626 // calculate arguments for second AES128 operation in C1 function 627 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 628 // p2 = padding || ia || ra 629 // "The least significant octet of ra becomes the least significant octet of p2 and 630 // the most significant octet of padding becomes the most significant octet of p2. 631 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 632 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 633 634 sm_key_t p2; 635 memset(p2, 0, 16); 636 memcpy(&p2[4], ia, 6); 637 memcpy(&p2[10], ra, 6); 638 log_info_key("p2", p2); 639 640 // c1 = e(k, t2_xor_p2) 641 int i; 642 for (i=0;i<16;i++){ 643 t3[i] = t2[i] ^ p2[i]; 644 } 645 log_info_key("t3", t3); 646 } 647 648 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 649 log_info_key("r1", r1); 650 log_info_key("r2", r2); 651 memcpy(&r_prime[8], &r2[8], 8); 652 memcpy(&r_prime[0], &r1[8], 8); 653 } 654 655 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 656 UNUSED(channel); 657 658 // log event 659 hci_dump_packet(packet_type, 1, packet, size); 660 // dispatch to all event handlers 661 btstack_linked_list_iterator_t it; 662 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 663 while (btstack_linked_list_iterator_has_next(&it)){ 664 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 665 entry->callback(packet_type, 0, packet, size); 666 } 667 } 668 669 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 670 event[0] = type; 671 event[1] = event_size - 2; 672 little_endian_store_16(event, 2, con_handle); 673 event[4] = addr_type; 674 reverse_bd_addr(address, &event[5]); 675 } 676 677 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 678 uint8_t event[11]; 679 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 680 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 681 } 682 683 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 684 uint8_t event[15]; 685 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 686 little_endian_store_32(event, 11, passkey); 687 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 688 } 689 690 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 691 // fetch addr and addr type from db 692 bd_addr_t identity_address; 693 int identity_address_type; 694 le_device_db_info(index, &identity_address_type, identity_address, NULL); 695 696 uint8_t event[20]; 697 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 698 event[11] = identity_address_type; 699 reverse_bd_addr(identity_address, &event[12]); 700 little_endian_store_16(event, 18, index); 701 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 702 } 703 704 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 705 uint8_t event[12]; 706 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 707 event[11] = status; 708 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 709 } 710 711 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 712 uint8_t event[13]; 713 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 714 event[11] = status; 715 event[12] = reason; 716 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 717 } 718 719 // decide on stk generation based on 720 // - pairing request 721 // - io capabilities 722 // - OOB data availability 723 static void sm_setup_tk(void){ 724 725 // default: just works 726 setup->sm_stk_generation_method = JUST_WORKS; 727 728 #ifdef ENABLE_LE_SECURE_CONNECTIONS 729 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 730 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 731 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 732 #else 733 setup->sm_use_secure_connections = 0; 734 #endif 735 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 736 737 738 // decide if OOB will be used based on SC vs. Legacy and oob flags 739 int use_oob = 0; 740 if (setup->sm_use_secure_connections){ 741 // In LE Secure Connections pairing, the out of band method is used if at least 742 // one device has the peer device's out of band authentication data available. 743 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 744 } else { 745 // In LE legacy pairing, the out of band method is used if both the devices have 746 // the other device's out of band authentication data available. 747 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 748 } 749 if (use_oob){ 750 log_info("SM: have OOB data"); 751 log_info_key("OOB", setup->sm_tk); 752 setup->sm_stk_generation_method = OOB; 753 return; 754 } 755 756 // If both devices have not set the MITM option in the Authentication Requirements 757 // Flags, then the IO capabilities shall be ignored and the Just Works association 758 // model shall be used. 759 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 760 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 761 log_info("SM: MITM not required by both -> JUST WORKS"); 762 return; 763 } 764 765 // Reset TK as it has been setup in sm_init_setup 766 sm_reset_tk(); 767 768 // Also use just works if unknown io capabilites 769 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 770 return; 771 } 772 773 // Otherwise the IO capabilities of the devices shall be used to determine the 774 // pairing method as defined in Table 2.4. 775 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 776 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 777 778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 779 // table not define by default 780 if (setup->sm_use_secure_connections){ 781 generation_method = stk_generation_method_with_secure_connection; 782 } 783 #endif 784 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 785 786 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 787 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 788 } 789 790 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 791 int flags = 0; 792 if (key_set & SM_KEYDIST_ENC_KEY){ 793 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 794 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 795 } 796 if (key_set & SM_KEYDIST_ID_KEY){ 797 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 798 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 799 } 800 if (key_set & SM_KEYDIST_SIGN){ 801 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 802 } 803 return flags; 804 } 805 806 static void sm_setup_key_distribution(uint8_t key_set){ 807 setup->sm_key_distribution_received_set = 0; 808 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 809 } 810 811 // CSRK Key Lookup 812 813 814 static int sm_address_resolution_idle(void){ 815 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 816 } 817 818 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 819 memcpy(sm_address_resolution_address, addr, 6); 820 sm_address_resolution_addr_type = addr_type; 821 sm_address_resolution_test = 0; 822 sm_address_resolution_mode = mode; 823 sm_address_resolution_context = context; 824 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 825 } 826 827 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 828 // check if already in list 829 btstack_linked_list_iterator_t it; 830 sm_lookup_entry_t * entry; 831 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 832 while(btstack_linked_list_iterator_has_next(&it)){ 833 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 834 if (entry->address_type != address_type) continue; 835 if (memcmp(entry->address, address, 6)) continue; 836 // already in list 837 return BTSTACK_BUSY; 838 } 839 entry = btstack_memory_sm_lookup_entry_get(); 840 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 841 entry->address_type = (bd_addr_type_t) address_type; 842 memcpy(entry->address, address, 6); 843 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 844 sm_run(); 845 return 0; 846 } 847 848 // CMAC calculation using AES Engineq 849 #ifdef USE_CMAC_ENGINE 850 851 static void sm_cmac_done_trampoline(void * arg){ 852 UNUSED(arg); 853 sm_cmac_active = 0; 854 (*sm_cmac_done_callback)(sm_cmac_hash); 855 sm_run(); 856 } 857 858 int sm_cmac_ready(void){ 859 return sm_cmac_active == 0; 860 } 861 862 // generic cmac calculation 863 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 864 sm_cmac_active = 1; 865 sm_cmac_done_callback = done_callback; 866 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 867 } 868 #endif 869 870 // cmac for ATT Message signing 871 #ifdef ENABLE_LE_SIGNED_WRITE 872 873 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 874 sm_cmac_active = 1; 875 sm_cmac_done_callback = done_callback; 876 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 877 } 878 879 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 880 if (offset >= sm_cmac_signed_write_message_len) { 881 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 882 return 0; 883 } 884 885 offset = sm_cmac_signed_write_message_len - 1 - offset; 886 887 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 888 if (offset < 3){ 889 return sm_cmac_signed_write_header[offset]; 890 } 891 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 892 if (offset < actual_message_len_incl_header){ 893 return sm_cmac_signed_write_message[offset - 3]; 894 } 895 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 896 } 897 898 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 899 // ATT Message Signing 900 sm_cmac_signed_write_header[0] = opcode; 901 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 902 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 903 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 904 sm_cmac_signed_write_message = message; 905 sm_cmac_signed_write_message_len = total_message_len; 906 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 907 } 908 #endif 909 910 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 911 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 912 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 913 switch (setup->sm_stk_generation_method){ 914 case PK_RESP_INPUT: 915 if (IS_RESPONDER(sm_conn->sm_role)){ 916 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 917 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 918 } else { 919 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 920 } 921 break; 922 case PK_INIT_INPUT: 923 if (IS_RESPONDER(sm_conn->sm_role)){ 924 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 925 } else { 926 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 927 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 928 } 929 break; 930 case PK_BOTH_INPUT: 931 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 932 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 933 break; 934 case NUMERIC_COMPARISON: 935 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 936 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 937 break; 938 case JUST_WORKS: 939 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 940 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 941 break; 942 case OOB: 943 // client already provided OOB data, let's skip notification. 944 break; 945 } 946 } 947 948 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 949 int recv_flags; 950 if (IS_RESPONDER(sm_conn->sm_role)){ 951 // slave / responder 952 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 953 } else { 954 // master / initiator 955 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 956 } 957 958 #ifdef ENABLE_LE_SECURE_CONNECTIONS 959 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 960 if (setup->sm_use_secure_connections){ 961 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 962 } 963 #endif 964 965 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 966 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 967 } 968 969 static void sm_done_for_handle(hci_con_handle_t con_handle){ 970 if (sm_active_connection_handle == con_handle){ 971 sm_timeout_stop(); 972 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 973 log_info("sm: connection 0x%x released setup context", con_handle); 974 975 #ifdef ENABLE_LE_SECURE_CONNECTIONS 976 // generate new ec key after each pairing (that used it) 977 if (setup->sm_use_secure_connections){ 978 sm_ec_generate_new_key(); 979 } 980 #endif 981 } 982 } 983 984 static int sm_key_distribution_flags_for_auth_req(void){ 985 986 int flags = SM_KEYDIST_ID_KEY; 987 if (sm_auth_req & SM_AUTHREQ_BONDING){ 988 // encryption and signing information only if bonding requested 989 flags |= SM_KEYDIST_ENC_KEY; 990 #ifdef ENABLE_LE_SIGNED_WRITE 991 flags |= SM_KEYDIST_SIGN; 992 #endif 993 } 994 return flags; 995 } 996 997 static void sm_reset_setup(void){ 998 // fill in sm setup 999 setup->sm_state_vars = 0; 1000 setup->sm_keypress_notification = 0; 1001 sm_reset_tk(); 1002 } 1003 1004 static void sm_init_setup(sm_connection_t * sm_conn){ 1005 1006 // fill in sm setup 1007 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1008 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1009 1010 // query client for Legacy Pairing OOB data 1011 setup->sm_have_oob_data = 0; 1012 if (sm_get_oob_data) { 1013 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1014 } 1015 1016 // if available and SC supported, also ask for SC OOB Data 1017 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1018 memset(setup->sm_ra, 0, 16); 1019 memset(setup->sm_rb, 0, 16); 1020 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1021 if (sm_get_sc_oob_data){ 1022 if (IS_RESPONDER(sm_conn->sm_role)){ 1023 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1024 sm_conn->sm_peer_addr_type, 1025 sm_conn->sm_peer_address, 1026 setup->sm_peer_confirm, 1027 setup->sm_ra); 1028 } else { 1029 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1030 sm_conn->sm_peer_addr_type, 1031 sm_conn->sm_peer_address, 1032 setup->sm_peer_confirm, 1033 setup->sm_rb); 1034 } 1035 } else { 1036 setup->sm_have_oob_data = 0; 1037 } 1038 } 1039 #endif 1040 1041 sm_pairing_packet_t * local_packet; 1042 if (IS_RESPONDER(sm_conn->sm_role)){ 1043 // slave 1044 local_packet = &setup->sm_s_pres; 1045 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1046 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1047 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1048 } else { 1049 // master 1050 local_packet = &setup->sm_m_preq; 1051 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1052 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1053 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1054 1055 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1056 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1057 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1058 } 1059 1060 uint8_t auth_req = sm_auth_req; 1061 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1062 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1063 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1064 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1065 } 1066 1067 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1068 1069 sm_pairing_packet_t * remote_packet; 1070 int remote_key_request; 1071 if (IS_RESPONDER(sm_conn->sm_role)){ 1072 // slave / responder 1073 remote_packet = &setup->sm_m_preq; 1074 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1075 } else { 1076 // master / initiator 1077 remote_packet = &setup->sm_s_pres; 1078 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1079 } 1080 1081 // check key size 1082 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1083 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1084 1085 // decide on STK generation method / SC 1086 sm_setup_tk(); 1087 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1088 1089 // check if STK generation method is acceptable by client 1090 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1091 1092 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1093 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1094 if (setup->sm_use_secure_connections){ 1095 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1096 } 1097 #endif 1098 1099 // identical to responder 1100 sm_setup_key_distribution(remote_key_request); 1101 1102 // JUST WORKS doens't provide authentication 1103 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1104 1105 return 0; 1106 } 1107 1108 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1109 1110 // cache and reset context 1111 int matched_device_id = sm_address_resolution_test; 1112 address_resolution_mode_t mode = sm_address_resolution_mode; 1113 void * context = sm_address_resolution_context; 1114 1115 // reset context 1116 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1117 sm_address_resolution_context = NULL; 1118 sm_address_resolution_test = -1; 1119 hci_con_handle_t con_handle = 0; 1120 1121 sm_connection_t * sm_connection; 1122 #ifdef ENABLE_LE_CENTRAL 1123 sm_key_t ltk; 1124 int have_ltk; 1125 int pairing_need; 1126 #endif 1127 switch (mode){ 1128 case ADDRESS_RESOLUTION_GENERAL: 1129 break; 1130 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1131 sm_connection = (sm_connection_t *) context; 1132 con_handle = sm_connection->sm_handle; 1133 switch (event){ 1134 case ADDRESS_RESOLUTION_SUCEEDED: 1135 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1136 sm_connection->sm_le_db_index = matched_device_id; 1137 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1138 if (sm_connection->sm_role) { 1139 // LTK request received before, IRK required -> start LTK calculation 1140 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1141 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1142 } 1143 break; 1144 } 1145 #ifdef ENABLE_LE_CENTRAL 1146 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1147 have_ltk = !sm_is_null_key(ltk); 1148 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1149 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1150 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1151 // reset requests 1152 sm_connection->sm_security_request_received = 0; 1153 sm_connection->sm_pairing_requested = 0; 1154 1155 // have ltk -> start encryption 1156 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1157 // "When a bond has been created between two devices, any reconnection should result in the local device 1158 // enabling or requesting encryption with the remote device before initiating any service request." 1159 if (have_ltk){ 1160 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1161 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1162 break; 1163 #else 1164 log_info("central: defer enabling encryption for bonded device"); 1165 #endif 1166 } 1167 // pairint_request -> send pairing request 1168 if (pairing_need){ 1169 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1170 break; 1171 } 1172 #endif 1173 break; 1174 case ADDRESS_RESOLUTION_FAILED: 1175 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1176 if (sm_connection->sm_role) { 1177 // LTK request received before, IRK required -> negative LTK reply 1178 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1179 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1180 } 1181 break; 1182 } 1183 #ifdef ENABLE_LE_CENTRAL 1184 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1185 sm_connection->sm_security_request_received = 0; 1186 sm_connection->sm_pairing_requested = 0; 1187 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1188 #endif 1189 break; 1190 } 1191 break; 1192 default: 1193 break; 1194 } 1195 1196 switch (event){ 1197 case ADDRESS_RESOLUTION_SUCEEDED: 1198 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1199 break; 1200 case ADDRESS_RESOLUTION_FAILED: 1201 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1202 break; 1203 } 1204 } 1205 1206 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1207 1208 int le_db_index = -1; 1209 1210 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1211 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1212 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1213 & SM_AUTHREQ_BONDING ) != 0; 1214 1215 if (bonding_enabed){ 1216 1217 // lookup device based on IRK 1218 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1219 int i; 1220 for (i=0; i < le_device_db_max_count(); i++){ 1221 sm_key_t irk; 1222 bd_addr_t address; 1223 int address_type = BD_ADDR_TYPE_UNKNOWN; 1224 le_device_db_info(i, &address_type, address, irk); 1225 // check if valid entry retrieved 1226 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1227 // compare IRK 1228 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1229 1230 log_info("sm: device found for IRK, updating"); 1231 le_db_index = i; 1232 break; 1233 } 1234 } else { 1235 // assert IRK is set to zero 1236 memset(setup->sm_peer_irk, 0, 16); 1237 } 1238 1239 // if not found, lookup via public address if possible 1240 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1241 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1242 int i; 1243 for (i=0; i < le_device_db_max_count(); i++){ 1244 bd_addr_t address; 1245 int address_type; 1246 le_device_db_info(i, &address_type, address, NULL); 1247 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1248 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1249 log_info("sm: device found for public address, updating"); 1250 le_db_index = i; 1251 break; 1252 } 1253 } 1254 } 1255 1256 // if not found, add to db 1257 if (le_db_index < 0) { 1258 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1259 } 1260 1261 if (le_db_index >= 0){ 1262 1263 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1264 1265 #ifdef ENABLE_LE_SIGNED_WRITE 1266 // store local CSRK 1267 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1268 log_info("sm: store local CSRK"); 1269 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1270 le_device_db_local_counter_set(le_db_index, 0); 1271 } 1272 1273 // store remote CSRK 1274 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1275 log_info("sm: store remote CSRK"); 1276 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1277 le_device_db_remote_counter_set(le_db_index, 0); 1278 } 1279 #endif 1280 // store encryption information for secure connections: LTK generated by ECDH 1281 if (setup->sm_use_secure_connections){ 1282 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1283 uint8_t zero_rand[8]; 1284 memset(zero_rand, 0, 8); 1285 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1286 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1287 } 1288 1289 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1290 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1291 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1292 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1293 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1294 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1295 1296 } 1297 } 1298 } else { 1299 log_info("Ignoring received keys, bonding not enabled"); 1300 } 1301 1302 // keep le_db_index 1303 sm_conn->sm_le_db_index = le_db_index; 1304 } 1305 1306 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1307 setup->sm_pairing_failed_reason = reason; 1308 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1309 } 1310 1311 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1312 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1313 } 1314 1315 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1316 1317 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1318 static int sm_passkey_used(stk_generation_method_t method); 1319 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1320 1321 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1322 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1323 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1324 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1325 } else { 1326 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1327 } 1328 } 1329 1330 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1331 if (IS_RESPONDER(sm_conn->sm_role)){ 1332 // Responder 1333 if (setup->sm_stk_generation_method == OOB){ 1334 // generate Nb 1335 log_info("Generate Nb"); 1336 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1337 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1338 } else { 1339 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1340 } 1341 } else { 1342 // Initiator role 1343 switch (setup->sm_stk_generation_method){ 1344 case JUST_WORKS: 1345 sm_sc_prepare_dhkey_check(sm_conn); 1346 break; 1347 1348 case NUMERIC_COMPARISON: 1349 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1350 break; 1351 case PK_INIT_INPUT: 1352 case PK_RESP_INPUT: 1353 case PK_BOTH_INPUT: 1354 if (setup->sm_passkey_bit < 20) { 1355 sm_sc_start_calculating_local_confirm(sm_conn); 1356 } else { 1357 sm_sc_prepare_dhkey_check(sm_conn); 1358 } 1359 break; 1360 case OOB: 1361 sm_sc_prepare_dhkey_check(sm_conn); 1362 break; 1363 } 1364 } 1365 } 1366 1367 static void sm_sc_cmac_done(uint8_t * hash){ 1368 log_info("sm_sc_cmac_done: "); 1369 log_info_hexdump(hash, 16); 1370 1371 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1372 sm_sc_oob_state = SM_SC_OOB_IDLE; 1373 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1374 return; 1375 } 1376 1377 sm_connection_t * sm_conn = sm_cmac_connection; 1378 sm_cmac_connection = NULL; 1379 #ifdef ENABLE_CLASSIC 1380 link_key_type_t link_key_type; 1381 #endif 1382 1383 switch (sm_conn->sm_engine_state){ 1384 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1385 memcpy(setup->sm_local_confirm, hash, 16); 1386 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1387 break; 1388 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1389 // check 1390 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1391 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1392 break; 1393 } 1394 sm_sc_state_after_receiving_random(sm_conn); 1395 break; 1396 case SM_SC_W4_CALCULATE_G2: { 1397 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1398 big_endian_store_32(setup->sm_tk, 12, vab); 1399 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1400 sm_trigger_user_response(sm_conn); 1401 break; 1402 } 1403 case SM_SC_W4_CALCULATE_F5_SALT: 1404 memcpy(setup->sm_t, hash, 16); 1405 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1406 break; 1407 case SM_SC_W4_CALCULATE_F5_MACKEY: 1408 memcpy(setup->sm_mackey, hash, 16); 1409 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1410 break; 1411 case SM_SC_W4_CALCULATE_F5_LTK: 1412 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1413 // Errata Service Release to the Bluetooth Specification: ESR09 1414 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1415 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1416 memcpy(setup->sm_ltk, hash, 16); 1417 memcpy(setup->sm_local_ltk, hash, 16); 1418 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1419 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1420 break; 1421 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1422 memcpy(setup->sm_local_dhkey_check, hash, 16); 1423 if (IS_RESPONDER(sm_conn->sm_role)){ 1424 // responder 1425 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1426 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1427 } else { 1428 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1429 } 1430 } else { 1431 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1432 } 1433 break; 1434 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1435 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1436 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1437 break; 1438 } 1439 if (IS_RESPONDER(sm_conn->sm_role)){ 1440 // responder 1441 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1442 } else { 1443 // initiator 1444 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1445 } 1446 break; 1447 case SM_SC_W4_CALCULATE_H6_ILK: 1448 memcpy(setup->sm_t, hash, 16); 1449 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1450 break; 1451 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1452 #ifdef ENABLE_CLASSIC 1453 reverse_128(hash, setup->sm_t); 1454 link_key_type = sm_conn->sm_connection_authenticated ? 1455 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1456 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1457 if (IS_RESPONDER(sm_conn->sm_role)){ 1458 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1459 } else { 1460 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1461 } 1462 #endif 1463 if (IS_RESPONDER(sm_conn->sm_role)){ 1464 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1465 } else { 1466 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1467 } 1468 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1469 sm_done_for_handle(sm_conn->sm_handle); 1470 break; 1471 default: 1472 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1473 break; 1474 } 1475 sm_run(); 1476 } 1477 1478 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1479 const uint16_t message_len = 65; 1480 sm_cmac_connection = sm_conn; 1481 memcpy(sm_cmac_sc_buffer, u, 32); 1482 memcpy(sm_cmac_sc_buffer+32, v, 32); 1483 sm_cmac_sc_buffer[64] = z; 1484 log_info("f4 key"); 1485 log_info_hexdump(x, 16); 1486 log_info("f4 message"); 1487 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1488 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1489 } 1490 1491 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1492 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1493 static const uint8_t f5_length[] = { 0x01, 0x00}; 1494 1495 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1496 log_info("f5_calculate_salt"); 1497 // calculate salt for f5 1498 const uint16_t message_len = 32; 1499 sm_cmac_connection = sm_conn; 1500 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1501 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1502 } 1503 1504 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1505 const uint16_t message_len = 53; 1506 sm_cmac_connection = sm_conn; 1507 1508 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1509 sm_cmac_sc_buffer[0] = 0; 1510 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1511 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1512 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1513 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1514 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1515 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1516 log_info("f5 key"); 1517 log_info_hexdump(t, 16); 1518 log_info("f5 message for MacKey"); 1519 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1520 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1521 } 1522 1523 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1524 sm_key56_t bd_addr_master, bd_addr_slave; 1525 bd_addr_master[0] = setup->sm_m_addr_type; 1526 bd_addr_slave[0] = setup->sm_s_addr_type; 1527 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1528 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1529 if (IS_RESPONDER(sm_conn->sm_role)){ 1530 // responder 1531 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1532 } else { 1533 // initiator 1534 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1535 } 1536 } 1537 1538 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1539 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1540 const uint16_t message_len = 53; 1541 sm_cmac_connection = sm_conn; 1542 sm_cmac_sc_buffer[0] = 1; 1543 // 1..52 setup before 1544 log_info("f5 key"); 1545 log_info_hexdump(t, 16); 1546 log_info("f5 message for LTK"); 1547 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1548 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1549 } 1550 1551 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1552 f5_ltk(sm_conn, setup->sm_t); 1553 } 1554 1555 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1556 const uint16_t message_len = 65; 1557 sm_cmac_connection = sm_conn; 1558 memcpy(sm_cmac_sc_buffer, n1, 16); 1559 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1560 memcpy(sm_cmac_sc_buffer+32, r, 16); 1561 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1562 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1563 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1564 log_info("f6 key"); 1565 log_info_hexdump(w, 16); 1566 log_info("f6 message"); 1567 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1568 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1569 } 1570 1571 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1572 // - U is 256 bits 1573 // - V is 256 bits 1574 // - X is 128 bits 1575 // - Y is 128 bits 1576 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1577 const uint16_t message_len = 80; 1578 sm_cmac_connection = sm_conn; 1579 memcpy(sm_cmac_sc_buffer, u, 32); 1580 memcpy(sm_cmac_sc_buffer+32, v, 32); 1581 memcpy(sm_cmac_sc_buffer+64, y, 16); 1582 log_info("g2 key"); 1583 log_info_hexdump(x, 16); 1584 log_info("g2 message"); 1585 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1586 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1587 } 1588 1589 static void g2_calculate(sm_connection_t * sm_conn) { 1590 // calc Va if numeric comparison 1591 if (IS_RESPONDER(sm_conn->sm_role)){ 1592 // responder 1593 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1594 } else { 1595 // initiator 1596 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1597 } 1598 } 1599 1600 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1601 uint8_t z = 0; 1602 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1603 // some form of passkey 1604 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1605 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1606 setup->sm_passkey_bit++; 1607 } 1608 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1609 } 1610 1611 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1612 // OOB 1613 if (setup->sm_stk_generation_method == OOB){ 1614 if (IS_RESPONDER(sm_conn->sm_role)){ 1615 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1616 } else { 1617 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1618 } 1619 return; 1620 } 1621 1622 uint8_t z = 0; 1623 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1624 // some form of passkey 1625 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1626 // sm_passkey_bit was increased before sending confirm value 1627 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1628 } 1629 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1630 } 1631 1632 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1633 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1634 1635 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1636 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1637 return; 1638 } else { 1639 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1640 } 1641 } 1642 1643 static void sm_sc_dhkey_calculated(void * arg){ 1644 sm_connection_t * sm_conn = (sm_connection_t *) arg; 1645 log_info("dhkey"); 1646 log_info_hexdump(&setup->sm_dhkey[0], 32); 1647 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1648 // trigger next step 1649 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1650 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1651 } 1652 sm_run(); 1653 } 1654 1655 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1656 // calculate DHKCheck 1657 sm_key56_t bd_addr_master, bd_addr_slave; 1658 bd_addr_master[0] = setup->sm_m_addr_type; 1659 bd_addr_slave[0] = setup->sm_s_addr_type; 1660 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1661 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1662 uint8_t iocap_a[3]; 1663 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1664 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1665 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1666 uint8_t iocap_b[3]; 1667 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1668 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1669 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1670 if (IS_RESPONDER(sm_conn->sm_role)){ 1671 // responder 1672 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1673 } else { 1674 // initiator 1675 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1676 } 1677 } 1678 1679 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1680 // validate E = f6() 1681 sm_key56_t bd_addr_master, bd_addr_slave; 1682 bd_addr_master[0] = setup->sm_m_addr_type; 1683 bd_addr_slave[0] = setup->sm_s_addr_type; 1684 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1685 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1686 1687 uint8_t iocap_a[3]; 1688 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1689 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1690 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1691 uint8_t iocap_b[3]; 1692 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1693 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1694 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1695 if (IS_RESPONDER(sm_conn->sm_role)){ 1696 // responder 1697 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1698 } else { 1699 // initiator 1700 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1701 } 1702 } 1703 1704 1705 // 1706 // Link Key Conversion Function h6 1707 // 1708 // h6(W, keyID) = AES-CMACW(keyID) 1709 // - W is 128 bits 1710 // - keyID is 32 bits 1711 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1712 const uint16_t message_len = 4; 1713 sm_cmac_connection = sm_conn; 1714 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1715 log_info("h6 key"); 1716 log_info_hexdump(w, 16); 1717 log_info("h6 message"); 1718 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1719 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1720 } 1721 1722 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1723 // Errata Service Release to the Bluetooth Specification: ESR09 1724 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1725 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1726 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1727 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1728 } 1729 1730 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1731 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1732 } 1733 1734 #endif 1735 1736 // key management legacy connections: 1737 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1738 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1739 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1740 // - responder reconnects: responder uses LTK receveived from master 1741 1742 // key management secure connections: 1743 // - both devices store same LTK from ECDH key exchange. 1744 1745 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1746 static void sm_load_security_info(sm_connection_t * sm_connection){ 1747 int encryption_key_size; 1748 int authenticated; 1749 int authorized; 1750 1751 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1752 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1753 &encryption_key_size, &authenticated, &authorized); 1754 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1755 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1756 sm_connection->sm_connection_authenticated = authenticated; 1757 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1758 } 1759 #endif 1760 1761 #ifdef ENABLE_LE_PERIPHERAL 1762 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1763 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1764 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1765 // re-establish used key encryption size 1766 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1767 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1768 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1769 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1770 log_info("sm: received ltk request with key size %u, authenticated %u", 1771 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1772 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1773 sm_run(); 1774 } 1775 #endif 1776 1777 static void sm_run(void){ 1778 1779 btstack_linked_list_iterator_t it; 1780 1781 // assert that stack has already bootet 1782 if (hci_get_state() != HCI_STATE_WORKING) return; 1783 1784 // assert that we can send at least commands 1785 if (!hci_can_send_command_packet_now()) return; 1786 1787 // 1788 // non-connection related behaviour 1789 // 1790 1791 // distributed key generation 1792 switch (dkg_state){ 1793 case DKG_CALC_IRK: 1794 // already busy? 1795 if (sm_aes128_state == SM_AES128_IDLE) { 1796 log_info("DKG_CALC_IRK started"); 1797 // IRK = d1(IR, 1, 0) 1798 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1799 sm_aes128_state = SM_AES128_ACTIVE; 1800 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1801 return; 1802 } 1803 break; 1804 case DKG_CALC_DHK: 1805 // already busy? 1806 if (sm_aes128_state == SM_AES128_IDLE) { 1807 log_info("DKG_CALC_DHK started"); 1808 // DHK = d1(IR, 3, 0) 1809 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1810 sm_aes128_state = SM_AES128_ACTIVE; 1811 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1812 return; 1813 } 1814 break; 1815 default: 1816 break; 1817 } 1818 1819 // random address updates 1820 switch (rau_state){ 1821 case RAU_GET_RANDOM: 1822 rau_state = RAU_W4_RANDOM; 1823 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 8, &sm_handle_random_result_rau, NULL); 1824 return; 1825 case RAU_GET_ENC: 1826 // already busy? 1827 if (sm_aes128_state == SM_AES128_IDLE) { 1828 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1829 sm_aes128_state = SM_AES128_ACTIVE; 1830 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1831 return; 1832 } 1833 break; 1834 case RAU_SET_ADDRESS: 1835 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1836 rau_state = RAU_IDLE; 1837 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1838 return; 1839 default: 1840 break; 1841 } 1842 1843 // CSRK Lookup 1844 // -- if csrk lookup ready, find connection that require csrk lookup 1845 if (sm_address_resolution_idle()){ 1846 hci_connections_get_iterator(&it); 1847 while(btstack_linked_list_iterator_has_next(&it)){ 1848 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1849 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1850 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1851 // and start lookup 1852 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1853 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1854 break; 1855 } 1856 } 1857 } 1858 1859 // -- if csrk lookup ready, resolved addresses for received addresses 1860 if (sm_address_resolution_idle()) { 1861 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1862 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1863 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1864 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1865 btstack_memory_sm_lookup_entry_free(entry); 1866 } 1867 } 1868 1869 // -- Continue with CSRK device lookup by public or resolvable private address 1870 if (!sm_address_resolution_idle()){ 1871 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1872 while (sm_address_resolution_test < le_device_db_max_count()){ 1873 int addr_type; 1874 bd_addr_t addr; 1875 sm_key_t irk; 1876 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1877 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1878 1879 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1880 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1881 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1882 break; 1883 } 1884 1885 if (sm_address_resolution_addr_type == 0){ 1886 sm_address_resolution_test++; 1887 continue; 1888 } 1889 1890 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1891 1892 log_info("LE Device Lookup: calculate AH"); 1893 log_info_key("IRK", irk); 1894 1895 memcpy(sm_aes128_key, irk, 16); 1896 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1897 sm_address_resolution_ah_calculation_active = 1; 1898 sm_aes128_state = SM_AES128_ACTIVE; 1899 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1900 return; 1901 } 1902 1903 if (sm_address_resolution_test >= le_device_db_max_count()){ 1904 log_info("LE Device Lookup: not found"); 1905 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1906 } 1907 } 1908 1909 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1910 switch (sm_sc_oob_state){ 1911 case SM_SC_OOB_W2_CALC_CONFIRM: 1912 if (!sm_cmac_ready()) break; 1913 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1914 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1915 return; 1916 default: 1917 break; 1918 } 1919 #endif 1920 1921 // assert that we can send at least commands - cmd might have been sent by crypto engine 1922 if (!hci_can_send_command_packet_now()) return; 1923 1924 // handle basic actions that don't requires the full context 1925 hci_connections_get_iterator(&it); 1926 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1927 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1928 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1929 switch(sm_connection->sm_engine_state){ 1930 // responder side 1931 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1932 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1933 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1934 return; 1935 1936 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1937 case SM_SC_RECEIVED_LTK_REQUEST: 1938 switch (sm_connection->sm_irk_lookup_state){ 1939 case IRK_LOOKUP_FAILED: 1940 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1941 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1942 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1943 return; 1944 default: 1945 break; 1946 } 1947 break; 1948 #endif 1949 default: 1950 break; 1951 } 1952 } 1953 1954 // 1955 // active connection handling 1956 // -- use loop to handle next connection if lock on setup context is released 1957 1958 while (1) { 1959 1960 // Find connections that requires setup context and make active if no other is locked 1961 hci_connections_get_iterator(&it); 1962 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1963 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1964 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1965 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1966 int done = 1; 1967 int err; 1968 UNUSED(err); 1969 1970 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1971 // assert ec key is ready 1972 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 1973 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 1974 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 1975 sm_ec_generate_new_key(); 1976 } 1977 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 1978 continue; 1979 } 1980 } 1981 #endif 1982 1983 switch (sm_connection->sm_engine_state) { 1984 #ifdef ENABLE_LE_PERIPHERAL 1985 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1986 // send packet if possible, 1987 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1988 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1989 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1990 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1991 } else { 1992 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1993 } 1994 // don't lock sxetup context yet 1995 done = 0; 1996 break; 1997 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1998 sm_reset_setup(); 1999 sm_init_setup(sm_connection); 2000 // recover pairing request 2001 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2002 err = sm_stk_generation_init(sm_connection); 2003 2004 #ifdef ENABLE_TESTING_SUPPORT 2005 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2006 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2007 err = test_pairing_failure; 2008 } 2009 #endif 2010 if (err){ 2011 setup->sm_pairing_failed_reason = err; 2012 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2013 break; 2014 } 2015 sm_timeout_start(sm_connection); 2016 // generate random number first, if we need to show passkey 2017 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2018 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2019 break; 2020 } 2021 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2022 break; 2023 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2024 sm_reset_setup(); 2025 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2026 break; 2027 2028 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2029 case SM_SC_RECEIVED_LTK_REQUEST: 2030 switch (sm_connection->sm_irk_lookup_state){ 2031 case IRK_LOOKUP_SUCCEEDED: 2032 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2033 // start using context by loading security info 2034 sm_reset_setup(); 2035 sm_load_security_info(sm_connection); 2036 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2037 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2038 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2039 break; 2040 } 2041 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2042 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2043 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2044 // don't lock setup context yet 2045 return; 2046 default: 2047 // just wait until IRK lookup is completed 2048 // don't lock setup context yet 2049 done = 0; 2050 break; 2051 } 2052 break; 2053 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2054 #endif /* ENABLE_LE_PERIPHERAL */ 2055 2056 #ifdef ENABLE_LE_CENTRAL 2057 case SM_INITIATOR_PH0_HAS_LTK: 2058 sm_reset_setup(); 2059 sm_load_security_info(sm_connection); 2060 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2061 break; 2062 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2063 sm_reset_setup(); 2064 sm_init_setup(sm_connection); 2065 sm_timeout_start(sm_connection); 2066 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2067 break; 2068 #endif 2069 2070 default: 2071 done = 0; 2072 break; 2073 } 2074 if (done){ 2075 sm_active_connection_handle = sm_connection->sm_handle; 2076 log_info("sm: connection 0x%04x locked setup context as %s, state %u", sm_active_connection_handle, sm_connection->sm_role ? "responder" : "initiator", sm_connection->sm_engine_state); 2077 } 2078 } 2079 2080 // 2081 // active connection handling 2082 // 2083 2084 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2085 2086 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2087 if (!connection) { 2088 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2089 return; 2090 } 2091 2092 // assert that we could send a SM PDU - not needed for all of the following 2093 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2094 log_info("cannot send now, requesting can send now event"); 2095 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2096 return; 2097 } 2098 2099 // send keypress notifications 2100 if (setup->sm_keypress_notification){ 2101 int i; 2102 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2103 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2104 uint8_t action = 0; 2105 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2106 if (flags & (1<<i)){ 2107 int clear_flag = 1; 2108 switch (i){ 2109 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2110 case SM_KEYPRESS_PASSKEY_CLEARED: 2111 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2112 default: 2113 break; 2114 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2115 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2116 num_actions--; 2117 clear_flag = num_actions == 0; 2118 break; 2119 } 2120 if (clear_flag){ 2121 flags &= ~(1<<i); 2122 } 2123 action = i; 2124 break; 2125 } 2126 } 2127 setup->sm_keypress_notification = (num_actions << 5) | flags; 2128 2129 // send keypress notification 2130 uint8_t buffer[2]; 2131 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2132 buffer[1] = action; 2133 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2134 2135 // try 2136 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2137 return; 2138 } 2139 2140 int key_distribution_flags; 2141 UNUSED(key_distribution_flags); 2142 2143 log_info("sm_run: state %u", connection->sm_engine_state); 2144 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2145 log_info("sm_run // cannot send"); 2146 } 2147 switch (connection->sm_engine_state){ 2148 2149 // general 2150 case SM_GENERAL_SEND_PAIRING_FAILED: { 2151 uint8_t buffer[2]; 2152 buffer[0] = SM_CODE_PAIRING_FAILED; 2153 buffer[1] = setup->sm_pairing_failed_reason; 2154 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2155 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2156 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2157 sm_done_for_handle(connection->sm_handle); 2158 break; 2159 } 2160 2161 // responding state 2162 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2163 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2164 if (!sm_cmac_ready()) break; 2165 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2166 sm_sc_calculate_local_confirm(connection); 2167 break; 2168 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2169 if (!sm_cmac_ready()) break; 2170 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2171 sm_sc_calculate_remote_confirm(connection); 2172 break; 2173 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2174 if (!sm_cmac_ready()) break; 2175 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2176 sm_sc_calculate_f6_for_dhkey_check(connection); 2177 break; 2178 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2179 if (!sm_cmac_ready()) break; 2180 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2181 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2182 break; 2183 case SM_SC_W2_CALCULATE_F5_SALT: 2184 if (!sm_cmac_ready()) break; 2185 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2186 f5_calculate_salt(connection); 2187 break; 2188 case SM_SC_W2_CALCULATE_F5_MACKEY: 2189 if (!sm_cmac_ready()) break; 2190 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2191 f5_calculate_mackey(connection); 2192 break; 2193 case SM_SC_W2_CALCULATE_F5_LTK: 2194 if (!sm_cmac_ready()) break; 2195 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2196 f5_calculate_ltk(connection); 2197 break; 2198 case SM_SC_W2_CALCULATE_G2: 2199 if (!sm_cmac_ready()) break; 2200 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2201 g2_calculate(connection); 2202 break; 2203 case SM_SC_W2_CALCULATE_H6_ILK: 2204 if (!sm_cmac_ready()) break; 2205 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2206 h6_calculate_ilk(connection); 2207 break; 2208 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2209 if (!sm_cmac_ready()) break; 2210 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2211 h6_calculate_br_edr_link_key(connection); 2212 break; 2213 #endif 2214 2215 #ifdef ENABLE_LE_CENTRAL 2216 // initiator side 2217 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2218 sm_key_t peer_ltk_flipped; 2219 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2220 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2221 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2222 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2223 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2224 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2225 return; 2226 } 2227 2228 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2229 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2230 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2231 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2232 sm_timeout_reset(connection); 2233 break; 2234 #endif 2235 2236 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2237 2238 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2239 int trigger_user_response = 0; 2240 2241 uint8_t buffer[65]; 2242 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2243 // 2244 reverse_256(&ec_q[0], &buffer[1]); 2245 reverse_256(&ec_q[32], &buffer[33]); 2246 2247 #ifdef ENABLE_TESTING_SUPPORT 2248 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2249 log_info("testing_support: invalidating public key"); 2250 // flip single bit of public key coordinate 2251 buffer[1] ^= 1; 2252 } 2253 #endif 2254 2255 // stk generation method 2256 // passkey entry: notify app to show passkey or to request passkey 2257 switch (setup->sm_stk_generation_method){ 2258 case JUST_WORKS: 2259 case NUMERIC_COMPARISON: 2260 if (IS_RESPONDER(connection->sm_role)){ 2261 // responder 2262 sm_sc_start_calculating_local_confirm(connection); 2263 } else { 2264 // initiator 2265 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2266 } 2267 break; 2268 case PK_INIT_INPUT: 2269 case PK_RESP_INPUT: 2270 case PK_BOTH_INPUT: 2271 // use random TK for display 2272 memcpy(setup->sm_ra, setup->sm_tk, 16); 2273 memcpy(setup->sm_rb, setup->sm_tk, 16); 2274 setup->sm_passkey_bit = 0; 2275 2276 if (IS_RESPONDER(connection->sm_role)){ 2277 // responder 2278 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2279 } else { 2280 // initiator 2281 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2282 } 2283 trigger_user_response = 1; 2284 break; 2285 case OOB: 2286 if (IS_RESPONDER(connection->sm_role)){ 2287 // responder 2288 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2289 } else { 2290 // initiator 2291 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2292 } 2293 break; 2294 } 2295 2296 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2297 sm_timeout_reset(connection); 2298 2299 // trigger user response after sending pdu 2300 if (trigger_user_response){ 2301 sm_trigger_user_response(connection); 2302 } 2303 break; 2304 } 2305 case SM_SC_SEND_CONFIRMATION: { 2306 uint8_t buffer[17]; 2307 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2308 reverse_128(setup->sm_local_confirm, &buffer[1]); 2309 if (IS_RESPONDER(connection->sm_role)){ 2310 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2311 } else { 2312 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2313 } 2314 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2315 sm_timeout_reset(connection); 2316 break; 2317 } 2318 case SM_SC_SEND_PAIRING_RANDOM: { 2319 uint8_t buffer[17]; 2320 buffer[0] = SM_CODE_PAIRING_RANDOM; 2321 reverse_128(setup->sm_local_nonce, &buffer[1]); 2322 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2323 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2324 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2325 if (IS_RESPONDER(connection->sm_role)){ 2326 // responder 2327 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2328 } else { 2329 // initiator 2330 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2331 } 2332 } else { 2333 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2334 if (IS_RESPONDER(connection->sm_role)){ 2335 // responder 2336 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2337 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2338 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2339 } else { 2340 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2341 sm_sc_prepare_dhkey_check(connection); 2342 } 2343 } else { 2344 // initiator 2345 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2346 } 2347 } 2348 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2349 sm_timeout_reset(connection); 2350 break; 2351 } 2352 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2353 uint8_t buffer[17]; 2354 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2355 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2356 2357 if (IS_RESPONDER(connection->sm_role)){ 2358 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2359 } else { 2360 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2361 } 2362 2363 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2364 sm_timeout_reset(connection); 2365 break; 2366 } 2367 2368 #endif 2369 2370 #ifdef ENABLE_LE_PERIPHERAL 2371 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2372 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2373 2374 // start with initiator key dist flags 2375 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2376 2377 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2378 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2379 if (setup->sm_use_secure_connections){ 2380 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2381 } 2382 #endif 2383 // setup in response 2384 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq) & key_distribution_flags); 2385 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq) & key_distribution_flags); 2386 2387 // update key distribution after ENC was dropped 2388 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2389 2390 if (setup->sm_use_secure_connections){ 2391 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2392 } else { 2393 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2394 } 2395 2396 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2397 sm_timeout_reset(connection); 2398 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2399 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2400 sm_trigger_user_response(connection); 2401 } 2402 return; 2403 #endif 2404 2405 case SM_PH2_SEND_PAIRING_RANDOM: { 2406 uint8_t buffer[17]; 2407 buffer[0] = SM_CODE_PAIRING_RANDOM; 2408 reverse_128(setup->sm_local_random, &buffer[1]); 2409 if (IS_RESPONDER(connection->sm_role)){ 2410 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2411 } else { 2412 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2413 } 2414 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2415 sm_timeout_reset(connection); 2416 break; 2417 } 2418 2419 case SM_PH2_C1_GET_ENC_A: 2420 // already busy? 2421 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2422 // calculate confirm using aes128 engine - step 1 2423 sm_c1_t1(setup->sm_local_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, sm_aes128_plaintext); 2424 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2425 sm_aes128_state = SM_AES128_ACTIVE; 2426 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2427 break; 2428 2429 case SM_PH2_C1_GET_ENC_C: 2430 // already busy? 2431 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2432 // calculate m_confirm using aes128 engine - step 1 2433 sm_c1_t1(setup->sm_peer_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, sm_aes128_plaintext); 2434 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2435 sm_aes128_state = SM_AES128_ACTIVE; 2436 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2437 break; 2438 2439 case SM_PH2_CALC_STK: 2440 // already busy? 2441 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2442 // calculate STK 2443 if (IS_RESPONDER(connection->sm_role)){ 2444 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2445 } else { 2446 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2447 } 2448 connection->sm_engine_state = SM_PH2_W4_STK; 2449 sm_aes128_state = SM_AES128_ACTIVE; 2450 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2451 break; 2452 2453 case SM_PH3_Y_GET_ENC: 2454 // already busy? 2455 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2456 // PH3B2 - calculate Y from - enc 2457 // Y = dm(DHK, Rand) 2458 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2459 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2460 sm_aes128_state = SM_AES128_ACTIVE; 2461 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, connection); 2462 break; 2463 2464 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2465 uint8_t buffer[17]; 2466 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2467 reverse_128(setup->sm_local_confirm, &buffer[1]); 2468 if (IS_RESPONDER(connection->sm_role)){ 2469 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2470 } else { 2471 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2472 } 2473 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2474 sm_timeout_reset(connection); 2475 return; 2476 } 2477 #ifdef ENABLE_LE_PERIPHERAL 2478 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2479 sm_key_t stk_flipped; 2480 reverse_128(setup->sm_ltk, stk_flipped); 2481 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2482 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2483 return; 2484 } 2485 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2486 sm_key_t ltk_flipped; 2487 reverse_128(setup->sm_ltk, ltk_flipped); 2488 connection->sm_engine_state = SM_RESPONDER_IDLE; 2489 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2490 sm_done_for_handle(connection->sm_handle); 2491 return; 2492 } 2493 case SM_RESPONDER_PH4_Y_GET_ENC: 2494 // already busy? 2495 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2496 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2497 // Y = dm(DHK, Rand) 2498 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2499 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2500 sm_aes128_state = SM_AES128_ACTIVE; 2501 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, connection); 2502 return; 2503 #endif 2504 #ifdef ENABLE_LE_CENTRAL 2505 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2506 sm_key_t stk_flipped; 2507 reverse_128(setup->sm_ltk, stk_flipped); 2508 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2509 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2510 return; 2511 } 2512 #endif 2513 2514 case SM_PH3_DISTRIBUTE_KEYS: 2515 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2516 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2517 uint8_t buffer[17]; 2518 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2519 reverse_128(setup->sm_ltk, &buffer[1]); 2520 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2521 sm_timeout_reset(connection); 2522 return; 2523 } 2524 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2525 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2526 uint8_t buffer[11]; 2527 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2528 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2529 reverse_64(setup->sm_local_rand, &buffer[3]); 2530 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2531 sm_timeout_reset(connection); 2532 return; 2533 } 2534 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2535 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2536 uint8_t buffer[17]; 2537 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2538 reverse_128(sm_persistent_irk, &buffer[1]); 2539 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2540 sm_timeout_reset(connection); 2541 return; 2542 } 2543 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2544 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2545 bd_addr_t local_address; 2546 uint8_t buffer[8]; 2547 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2548 switch (gap_random_address_get_mode()){ 2549 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2550 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2551 // public or static random 2552 gap_le_get_own_address(&buffer[1], local_address); 2553 break; 2554 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2555 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2556 // fallback to public 2557 gap_local_bd_addr(local_address); 2558 buffer[1] = 0; 2559 break; 2560 } 2561 reverse_bd_addr(local_address, &buffer[2]); 2562 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2563 sm_timeout_reset(connection); 2564 return; 2565 } 2566 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2567 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2568 2569 // hack to reproduce test runs 2570 if (test_use_fixed_local_csrk){ 2571 memset(setup->sm_local_csrk, 0xcc, 16); 2572 } 2573 2574 uint8_t buffer[17]; 2575 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2576 reverse_128(setup->sm_local_csrk, &buffer[1]); 2577 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2578 sm_timeout_reset(connection); 2579 return; 2580 } 2581 2582 // keys are sent 2583 if (IS_RESPONDER(connection->sm_role)){ 2584 // slave -> receive master keys if any 2585 if (sm_key_distribution_all_received(connection)){ 2586 sm_key_distribution_handle_all_received(connection); 2587 connection->sm_engine_state = SM_RESPONDER_IDLE; 2588 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2589 sm_done_for_handle(connection->sm_handle); 2590 } else { 2591 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2592 } 2593 } else { 2594 // master -> all done 2595 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2596 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2597 sm_done_for_handle(connection->sm_handle); 2598 } 2599 break; 2600 2601 default: 2602 break; 2603 } 2604 2605 // check again if active connection was released 2606 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2607 } 2608 } 2609 2610 // sm_aes128_state stays active 2611 static void sm_handle_encryption_result_enc_a(void *arg){ 2612 sm_connection_t * connection = (sm_connection_t*) arg; 2613 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2614 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, connection); 2615 } 2616 2617 static void sm_handle_encryption_result_enc_b(void *arg){ 2618 sm_connection_t * connection = (sm_connection_t*) arg; 2619 sm_aes128_state = SM_AES128_IDLE; 2620 log_info_key("c1!", setup->sm_local_confirm); 2621 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2622 sm_run(); 2623 } 2624 2625 // sm_aes128_state stays active 2626 static void sm_handle_encryption_result_enc_c(void *arg){ 2627 sm_connection_t * connection = (sm_connection_t*) arg; 2628 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2629 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, connection); 2630 } 2631 2632 static void sm_handle_encryption_result_enc_d(void * arg){ 2633 sm_connection_t * connection = (sm_connection_t*) arg; 2634 sm_aes128_state = SM_AES128_IDLE; 2635 log_info_key("c1!", sm_aes128_ciphertext); 2636 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2637 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2638 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2639 sm_run(); 2640 return; 2641 } 2642 if (IS_RESPONDER(connection->sm_role)){ 2643 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2644 sm_run(); 2645 } else { 2646 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2647 sm_aes128_state = SM_AES128_ACTIVE; 2648 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2649 } 2650 } 2651 2652 static void sm_handle_encryption_result_enc_stk(void *arg){ 2653 sm_connection_t * connection = (sm_connection_t*) arg; 2654 sm_aes128_state = SM_AES128_IDLE; 2655 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2656 log_info_key("stk", setup->sm_ltk); 2657 if (IS_RESPONDER(connection->sm_role)){ 2658 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2659 } else { 2660 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2661 } 2662 sm_run(); 2663 } 2664 2665 // sm_aes128_state stays active 2666 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2667 sm_connection_t * connection = (sm_connection_t*) arg; 2668 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2669 log_info_hex16("y", setup->sm_local_y); 2670 // PH3B3 - calculate EDIV 2671 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2672 log_info_hex16("ediv", setup->sm_local_ediv); 2673 // PH3B4 - calculate LTK - enc 2674 // LTK = d1(ER, DIV, 0)) 2675 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2676 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, connection); 2677 } 2678 2679 #ifdef ENABLE_LE_PERIPHERAL 2680 // sm_aes128_state stays active 2681 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2682 sm_connection_t * connection = (sm_connection_t*) arg; 2683 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2684 log_info_hex16("y", setup->sm_local_y); 2685 2686 // PH3B3 - calculate DIV 2687 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2688 log_info_hex16("ediv", setup->sm_local_ediv); 2689 // PH3B4 - calculate LTK - enc 2690 // LTK = d1(ER, DIV, 0)) 2691 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2692 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, connection); 2693 } 2694 #endif 2695 2696 // sm_aes128_state stays active 2697 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2698 sm_connection_t * connection = (sm_connection_t*) arg; 2699 log_info_key("ltk", setup->sm_ltk); 2700 // calc CSRK next 2701 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2702 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, connection); 2703 } 2704 2705 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2706 sm_connection_t * connection = (sm_connection_t*) arg; 2707 sm_aes128_state = SM_AES128_IDLE; 2708 log_info_key("csrk", setup->sm_local_csrk); 2709 if (setup->sm_key_distribution_send_set){ 2710 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2711 } else { 2712 // no keys to send, just continue 2713 if (IS_RESPONDER(connection->sm_role)){ 2714 // slave -> receive master keys 2715 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2716 } else { 2717 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2718 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2719 } else { 2720 // master -> all done 2721 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2722 sm_done_for_handle(connection->sm_handle); 2723 } 2724 } 2725 } 2726 sm_run(); 2727 } 2728 2729 #ifdef ENABLE_LE_PERIPHERAL 2730 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2731 sm_connection_t * connection = (sm_connection_t*) arg; 2732 sm_aes128_state = SM_AES128_IDLE; 2733 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2734 log_info_key("ltk", setup->sm_ltk); 2735 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2736 sm_run(); 2737 } 2738 #endif 2739 2740 static void sm_handle_encryption_result_address_resolution(void *arg){ 2741 UNUSED(arg); 2742 sm_aes128_state = SM_AES128_IDLE; 2743 sm_address_resolution_ah_calculation_active = 0; 2744 // compare calulated address against connecting device 2745 uint8_t * hash = &sm_aes128_ciphertext[13]; 2746 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2747 log_info("LE Device Lookup: matched resolvable private address"); 2748 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2749 sm_run(); 2750 return; 2751 } 2752 // no match, try next 2753 sm_address_resolution_test++; 2754 sm_run(); 2755 } 2756 2757 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2758 UNUSED(arg); 2759 sm_aes128_state = SM_AES128_IDLE; 2760 log_info_key("irk", sm_persistent_irk); 2761 dkg_state = DKG_CALC_DHK; 2762 sm_run(); 2763 } 2764 2765 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2766 UNUSED(arg); 2767 sm_aes128_state = SM_AES128_IDLE; 2768 log_info_key("dhk", sm_persistent_dhk); 2769 dkg_state = DKG_READY; 2770 // DKG calculation complete => SM Init Finished 2771 sm_run(); 2772 } 2773 2774 static void sm_handle_encryption_result_rau(void *arg){ 2775 UNUSED(arg); 2776 sm_aes128_state = SM_AES128_IDLE; 2777 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2778 rau_state = RAU_SET_ADDRESS; 2779 sm_run(); 2780 } 2781 2782 static void sm_handle_random_result_rau(void * arg){ 2783 UNUSED(arg); 2784 // non-resolvable vs. resolvable 2785 switch (gap_random_adress_type){ 2786 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2787 // resolvable: use random as prand and calc address hash 2788 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2789 sm_random_address[0] &= 0x3f; 2790 sm_random_address[0] |= 0x40; 2791 rau_state = RAU_GET_ENC; 2792 break; 2793 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2794 default: 2795 // "The two most significant bits of the address shall be equal to ‘0’"" 2796 sm_random_address[0] &= 0x3f; 2797 rau_state = RAU_SET_ADDRESS; 2798 break; 2799 } 2800 sm_run(); 2801 } 2802 2803 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2804 static void sm_handle_random_result_sc_get_random(void * arg){ 2805 sm_connection_t * connection = (sm_connection_t*) arg; 2806 2807 // OOB 2808 if (setup->sm_stk_generation_method == OOB){ 2809 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2810 sm_run(); 2811 return; 2812 } 2813 2814 // initiator & jw/nc -> send pairing random 2815 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2816 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2817 } else { 2818 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2819 } 2820 sm_run(); 2821 } 2822 #endif 2823 2824 static void sm_handle_random_result_ph2_random(void * arg){ 2825 sm_connection_t * connection = (sm_connection_t*) arg; 2826 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2827 sm_run(); 2828 } 2829 2830 static void sm_handle_random_result_ph2_tk(void * arg){ 2831 sm_connection_t * connection = (sm_connection_t*) arg; 2832 sm_reset_tk(); 2833 uint32_t tk; 2834 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2835 // map random to 0-999999 without speding much cycles on a modulus operation 2836 tk = little_endian_read_32(sm_random_data,0); 2837 tk = tk & 0xfffff; // 1048575 2838 if (tk >= 999999){ 2839 tk = tk - 999999; 2840 } 2841 } else { 2842 // override with pre-defined passkey 2843 tk = sm_fixed_passkey_in_display_role; 2844 } 2845 big_endian_store_32(setup->sm_tk, 12, tk); 2846 if (IS_RESPONDER(connection->sm_role)){ 2847 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2848 } else { 2849 if (setup->sm_use_secure_connections){ 2850 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2851 } else { 2852 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2853 sm_trigger_user_response(connection); 2854 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2855 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2856 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2857 } 2858 } 2859 } 2860 sm_run(); 2861 } 2862 2863 static void sm_handle_random_result_ph3_div(void * arg){ 2864 sm_connection_t * connection = (sm_connection_t*) arg; 2865 // use 16 bit from random value as div 2866 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2867 log_info_hex16("div", setup->sm_local_div); 2868 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2869 sm_run(); 2870 } 2871 2872 static void sm_handle_random_result_ph3_random(void * arg){ 2873 sm_connection_t * connection = (sm_connection_t*) arg; 2874 reverse_64(sm_random_data, setup->sm_local_rand); 2875 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2876 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2877 // no db for authenticated flag hack: store flag in bit 4 of LSB 2878 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2879 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2880 } 2881 2882 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2883 2884 UNUSED(channel); // ok: there is no channel 2885 UNUSED(size); // ok: fixed format HCI events 2886 2887 sm_connection_t * sm_conn; 2888 hci_con_handle_t con_handle; 2889 2890 switch (packet_type) { 2891 2892 case HCI_EVENT_PACKET: 2893 switch (hci_event_packet_get_type(packet)) { 2894 2895 case BTSTACK_EVENT_STATE: 2896 // bt stack activated, get started 2897 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2898 log_info("HCI Working!"); 2899 2900 // update dpk calculation state for pts testing 2901 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2902 } 2903 break; 2904 2905 case HCI_EVENT_LE_META: 2906 switch (packet[2]) { 2907 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2908 2909 log_info("sm: connected"); 2910 2911 if (packet[3]) return; // connection failed 2912 2913 con_handle = little_endian_read_16(packet, 4); 2914 sm_conn = sm_get_connection_for_handle(con_handle); 2915 if (!sm_conn) break; 2916 2917 sm_conn->sm_handle = con_handle; 2918 sm_conn->sm_role = packet[6]; 2919 sm_conn->sm_peer_addr_type = packet[7]; 2920 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 2921 2922 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2923 2924 // reset security properties 2925 sm_conn->sm_connection_encrypted = 0; 2926 sm_conn->sm_connection_authenticated = 0; 2927 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2928 sm_conn->sm_le_db_index = -1; 2929 2930 // prepare CSRK lookup (does not involve setup) 2931 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2932 2933 // just connected -> everything else happens in sm_run() 2934 if (IS_RESPONDER(sm_conn->sm_role)){ 2935 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2936 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2937 if (sm_slave_request_security) { 2938 // request security if requested by app 2939 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2940 } else { 2941 // otherwise, wait for pairing request 2942 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2943 } 2944 } 2945 break; 2946 } else { 2947 // master 2948 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2949 } 2950 break; 2951 2952 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2953 con_handle = little_endian_read_16(packet, 3); 2954 sm_conn = sm_get_connection_for_handle(con_handle); 2955 if (!sm_conn) break; 2956 2957 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2958 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2959 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2960 break; 2961 } 2962 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2963 // PH2 SEND LTK as we need to exchange keys in PH3 2964 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2965 break; 2966 } 2967 2968 // store rand and ediv 2969 reverse_64(&packet[5], sm_conn->sm_local_rand); 2970 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2971 2972 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2973 // potentially stored LTK is from the master 2974 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2975 if (sm_reconstruct_ltk_without_le_device_db_entry){ 2976 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2977 break; 2978 } 2979 // additionally check if remote is in LE Device DB if requested 2980 switch(sm_conn->sm_irk_lookup_state){ 2981 case IRK_LOOKUP_FAILED: 2982 log_info("LTK Request: device not in device db"); 2983 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2984 break; 2985 case IRK_LOOKUP_SUCCEEDED: 2986 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2987 break; 2988 default: 2989 // wait for irk look doen 2990 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 2991 break; 2992 } 2993 break; 2994 } 2995 2996 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2997 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 2998 #else 2999 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3000 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3001 #endif 3002 break; 3003 3004 default: 3005 break; 3006 } 3007 break; 3008 3009 case HCI_EVENT_ENCRYPTION_CHANGE: 3010 con_handle = little_endian_read_16(packet, 3); 3011 sm_conn = sm_get_connection_for_handle(con_handle); 3012 if (!sm_conn) break; 3013 3014 sm_conn->sm_connection_encrypted = packet[5]; 3015 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3016 sm_conn->sm_actual_encryption_key_size); 3017 log_info("event handler, state %u", sm_conn->sm_engine_state); 3018 3019 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3020 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3021 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3022 // notify client, if pairing was requested before 3023 if (sm_conn->sm_pairing_requested){ 3024 sm_conn->sm_pairing_requested = 0; 3025 if (sm_conn->sm_connection_encrypted){ 3026 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3027 } else { 3028 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3029 } 3030 } 3031 sm_done_for_handle(sm_conn->sm_handle); 3032 break; 3033 } 3034 3035 if (!sm_conn->sm_connection_encrypted) break; 3036 3037 // continue pairing 3038 switch (sm_conn->sm_engine_state){ 3039 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3040 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3041 sm_done_for_handle(sm_conn->sm_handle); 3042 break; 3043 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3044 if (IS_RESPONDER(sm_conn->sm_role)){ 3045 // slave 3046 if (setup->sm_use_secure_connections){ 3047 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3048 } else { 3049 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3050 } 3051 } else { 3052 // master 3053 if (sm_key_distribution_all_received(sm_conn)){ 3054 // skip receiving keys as there are none 3055 sm_key_distribution_handle_all_received(sm_conn); 3056 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3057 } else { 3058 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3059 } 3060 } 3061 break; 3062 default: 3063 break; 3064 } 3065 break; 3066 3067 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3068 con_handle = little_endian_read_16(packet, 3); 3069 sm_conn = sm_get_connection_for_handle(con_handle); 3070 if (!sm_conn) break; 3071 3072 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3073 log_info("event handler, state %u", sm_conn->sm_engine_state); 3074 // continue if part of initial pairing 3075 switch (sm_conn->sm_engine_state){ 3076 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3077 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3078 sm_done_for_handle(sm_conn->sm_handle); 3079 break; 3080 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3081 if (IS_RESPONDER(sm_conn->sm_role)){ 3082 // slave 3083 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3084 } else { 3085 // master 3086 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3087 } 3088 break; 3089 default: 3090 break; 3091 } 3092 break; 3093 3094 3095 case HCI_EVENT_DISCONNECTION_COMPLETE: 3096 con_handle = little_endian_read_16(packet, 3); 3097 sm_done_for_handle(con_handle); 3098 sm_conn = sm_get_connection_for_handle(con_handle); 3099 if (!sm_conn) break; 3100 3101 // delete stored bonding on disconnect with authentication failure in ph0 3102 if (sm_conn->sm_role == 0 3103 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3104 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3105 le_device_db_remove(sm_conn->sm_le_db_index); 3106 } 3107 3108 // pairing failed, if it was ongoing 3109 if (sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED && sm_conn->sm_engine_state != SM_GENERAL_IDLE){ 3110 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3111 } 3112 3113 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3114 sm_conn->sm_handle = 0; 3115 break; 3116 3117 case HCI_EVENT_COMMAND_COMPLETE: 3118 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3119 // set local addr for le device db 3120 bd_addr_t addr; 3121 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3122 le_device_db_set_local_bd_addr(addr); 3123 } 3124 break; 3125 default: 3126 break; 3127 } 3128 break; 3129 default: 3130 break; 3131 } 3132 3133 sm_run(); 3134 } 3135 3136 static inline int sm_calc_actual_encryption_key_size(int other){ 3137 if (other < sm_min_encryption_key_size) return 0; 3138 if (other < sm_max_encryption_key_size) return other; 3139 return sm_max_encryption_key_size; 3140 } 3141 3142 3143 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3144 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3145 switch (method){ 3146 case JUST_WORKS: 3147 case NUMERIC_COMPARISON: 3148 return 1; 3149 default: 3150 return 0; 3151 } 3152 } 3153 // responder 3154 3155 static int sm_passkey_used(stk_generation_method_t method){ 3156 switch (method){ 3157 case PK_RESP_INPUT: 3158 return 1; 3159 default: 3160 return 0; 3161 } 3162 } 3163 3164 static int sm_passkey_entry(stk_generation_method_t method){ 3165 switch (method){ 3166 case PK_RESP_INPUT: 3167 case PK_INIT_INPUT: 3168 case PK_BOTH_INPUT: 3169 return 1; 3170 default: 3171 return 0; 3172 } 3173 } 3174 3175 #endif 3176 3177 /** 3178 * @return ok 3179 */ 3180 static int sm_validate_stk_generation_method(void){ 3181 // check if STK generation method is acceptable by client 3182 switch (setup->sm_stk_generation_method){ 3183 case JUST_WORKS: 3184 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3185 case PK_RESP_INPUT: 3186 case PK_INIT_INPUT: 3187 case PK_BOTH_INPUT: 3188 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3189 case OOB: 3190 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3191 case NUMERIC_COMPARISON: 3192 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3193 default: 3194 return 0; 3195 } 3196 } 3197 3198 // size of complete sm_pdu used to validate input 3199 static const uint8_t sm_pdu_size[] = { 3200 0, // 0x00 invalid opcode 3201 7, // 0x01 pairing request 3202 7, // 0x02 pairing response 3203 17, // 0x03 pairing confirm 3204 17, // 0x04 pairing random 3205 2, // 0x05 pairing failed 3206 17, // 0x06 encryption information 3207 11, // 0x07 master identification 3208 17, // 0x08 identification information 3209 8, // 0x09 identify address information 3210 17, // 0x0a signing information 3211 2, // 0x0b security request 3212 65, // 0x0c pairing public key 3213 17, // 0x0d pairing dhk check 3214 2, // 0x0e keypress notification 3215 }; 3216 3217 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3218 3219 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3220 sm_run(); 3221 } 3222 3223 if (packet_type != SM_DATA_PACKET) return; 3224 if (size == 0) return; 3225 3226 uint8_t sm_pdu_code = packet[0]; 3227 3228 // validate pdu size 3229 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3230 if (sm_pdu_size[sm_pdu_code] != size) return; 3231 3232 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3233 if (!sm_conn) return; 3234 3235 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3236 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3237 sm_done_for_handle(con_handle); 3238 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3239 return; 3240 } 3241 3242 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3243 3244 int err; 3245 UNUSED(err); 3246 3247 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3248 uint8_t buffer[5]; 3249 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3250 buffer[1] = 3; 3251 little_endian_store_16(buffer, 2, con_handle); 3252 buffer[4] = packet[1]; 3253 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3254 return; 3255 } 3256 3257 switch (sm_conn->sm_engine_state){ 3258 3259 // a sm timeout requries a new physical connection 3260 case SM_GENERAL_TIMEOUT: 3261 return; 3262 3263 #ifdef ENABLE_LE_CENTRAL 3264 3265 // Initiator 3266 case SM_INITIATOR_CONNECTED: 3267 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3268 sm_pdu_received_in_wrong_state(sm_conn); 3269 break; 3270 } 3271 3272 // IRK complete? 3273 switch (sm_conn->sm_irk_lookup_state){ 3274 case IRK_LOOKUP_FAILED: 3275 case IRK_LOOKUP_SUCCEEDED: 3276 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3277 break; 3278 default: 3279 break; 3280 } 3281 3282 // otherwise, store security request 3283 sm_conn->sm_security_request_received = 1; 3284 break; 3285 3286 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3287 // Core 5, Vol 3, Part H, 2.4.6: 3288 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3289 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3290 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3291 log_info("Ignoring Security Request"); 3292 break; 3293 } 3294 3295 // all other pdus are incorrect 3296 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3297 sm_pdu_received_in_wrong_state(sm_conn); 3298 break; 3299 } 3300 3301 // store pairing request 3302 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3303 err = sm_stk_generation_init(sm_conn); 3304 3305 #ifdef ENABLE_TESTING_SUPPORT 3306 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3307 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3308 err = test_pairing_failure; 3309 } 3310 #endif 3311 3312 if (err){ 3313 setup->sm_pairing_failed_reason = err; 3314 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3315 break; 3316 } 3317 3318 // generate random number first, if we need to show passkey 3319 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3320 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3321 break; 3322 } 3323 3324 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3325 if (setup->sm_use_secure_connections){ 3326 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3327 if (setup->sm_stk_generation_method == JUST_WORKS){ 3328 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3329 sm_trigger_user_response(sm_conn); 3330 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3331 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3332 } 3333 } else { 3334 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3335 } 3336 break; 3337 } 3338 #endif 3339 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3340 sm_trigger_user_response(sm_conn); 3341 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3342 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3343 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3344 } 3345 break; 3346 3347 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3348 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3349 sm_pdu_received_in_wrong_state(sm_conn); 3350 break; 3351 } 3352 3353 // store s_confirm 3354 reverse_128(&packet[1], setup->sm_peer_confirm); 3355 3356 #ifdef ENABLE_TESTING_SUPPORT 3357 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3358 log_info("testing_support: reset confirm value"); 3359 memset(setup->sm_peer_confirm, 0, 16); 3360 } 3361 #endif 3362 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3363 break; 3364 3365 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3366 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3367 sm_pdu_received_in_wrong_state(sm_conn); 3368 break;; 3369 } 3370 3371 // received random value 3372 reverse_128(&packet[1], setup->sm_peer_random); 3373 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3374 break; 3375 #endif 3376 3377 #ifdef ENABLE_LE_PERIPHERAL 3378 // Responder 3379 case SM_RESPONDER_IDLE: 3380 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3381 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3382 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3383 sm_pdu_received_in_wrong_state(sm_conn); 3384 break;; 3385 } 3386 3387 // store pairing request 3388 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3389 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3390 break; 3391 #endif 3392 3393 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3394 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3395 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3396 sm_pdu_received_in_wrong_state(sm_conn); 3397 break; 3398 } 3399 3400 // store public key for DH Key calculation 3401 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3402 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3403 3404 // validate public key 3405 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3406 if (err){ 3407 log_error("sm: peer public key invalid %x", err); 3408 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3409 break; 3410 } 3411 3412 // start calculating dhkey 3413 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3414 3415 3416 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3417 if (IS_RESPONDER(sm_conn->sm_role)){ 3418 // responder 3419 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3420 } else { 3421 // initiator 3422 // stk generation method 3423 // passkey entry: notify app to show passkey or to request passkey 3424 switch (setup->sm_stk_generation_method){ 3425 case JUST_WORKS: 3426 case NUMERIC_COMPARISON: 3427 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3428 break; 3429 case PK_RESP_INPUT: 3430 sm_sc_start_calculating_local_confirm(sm_conn); 3431 break; 3432 case PK_INIT_INPUT: 3433 case PK_BOTH_INPUT: 3434 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3435 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3436 break; 3437 } 3438 sm_sc_start_calculating_local_confirm(sm_conn); 3439 break; 3440 case OOB: 3441 // generate Nx 3442 log_info("Generate Na"); 3443 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3444 break; 3445 } 3446 } 3447 break; 3448 3449 case SM_SC_W4_CONFIRMATION: 3450 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3451 sm_pdu_received_in_wrong_state(sm_conn); 3452 break; 3453 } 3454 // received confirm value 3455 reverse_128(&packet[1], setup->sm_peer_confirm); 3456 3457 #ifdef ENABLE_TESTING_SUPPORT 3458 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3459 log_info("testing_support: reset confirm value"); 3460 memset(setup->sm_peer_confirm, 0, 16); 3461 } 3462 #endif 3463 if (IS_RESPONDER(sm_conn->sm_role)){ 3464 // responder 3465 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3466 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3467 // still waiting for passkey 3468 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3469 break; 3470 } 3471 } 3472 sm_sc_start_calculating_local_confirm(sm_conn); 3473 } else { 3474 // initiator 3475 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3476 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3477 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3478 } else { 3479 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3480 } 3481 } 3482 break; 3483 3484 case SM_SC_W4_PAIRING_RANDOM: 3485 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3486 sm_pdu_received_in_wrong_state(sm_conn); 3487 break; 3488 } 3489 3490 // received random value 3491 reverse_128(&packet[1], setup->sm_peer_nonce); 3492 3493 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3494 // only check for JUST WORK/NC in initiator role OR passkey entry 3495 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3496 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3497 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3498 break; 3499 } 3500 3501 // OOB 3502 if (setup->sm_stk_generation_method == OOB){ 3503 3504 // setup local random, set to zero if remote did not receive our data 3505 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3506 if (IS_RESPONDER(sm_conn->sm_role)){ 3507 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3508 log_info("Reset rb as A does not have OOB data"); 3509 memset(setup->sm_rb, 0, 16); 3510 } else { 3511 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3512 log_info("Use stored rb"); 3513 log_info_hexdump(setup->sm_rb, 16); 3514 } 3515 } else { 3516 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3517 log_info("Reset ra as B does not have OOB data"); 3518 memset(setup->sm_ra, 0, 16); 3519 } else { 3520 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3521 log_info("Use stored ra"); 3522 log_info_hexdump(setup->sm_ra, 16); 3523 } 3524 } 3525 3526 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3527 if (setup->sm_have_oob_data){ 3528 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3529 break; 3530 } 3531 } 3532 3533 // TODO: we only get here for Responder role with JW/NC 3534 sm_sc_state_after_receiving_random(sm_conn); 3535 break; 3536 3537 case SM_SC_W2_CALCULATE_G2: 3538 case SM_SC_W4_CALCULATE_G2: 3539 case SM_SC_W4_CALCULATE_DHKEY: 3540 case SM_SC_W2_CALCULATE_F5_SALT: 3541 case SM_SC_W4_CALCULATE_F5_SALT: 3542 case SM_SC_W2_CALCULATE_F5_MACKEY: 3543 case SM_SC_W4_CALCULATE_F5_MACKEY: 3544 case SM_SC_W2_CALCULATE_F5_LTK: 3545 case SM_SC_W4_CALCULATE_F5_LTK: 3546 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3547 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3548 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3549 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3550 sm_pdu_received_in_wrong_state(sm_conn); 3551 break; 3552 } 3553 // store DHKey Check 3554 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3555 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3556 3557 // have we been only waiting for dhkey check command? 3558 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3559 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3560 } 3561 break; 3562 #endif 3563 3564 #ifdef ENABLE_LE_PERIPHERAL 3565 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3566 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3567 sm_pdu_received_in_wrong_state(sm_conn); 3568 break; 3569 } 3570 3571 // received confirm value 3572 reverse_128(&packet[1], setup->sm_peer_confirm); 3573 3574 #ifdef ENABLE_TESTING_SUPPORT 3575 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3576 log_info("testing_support: reset confirm value"); 3577 memset(setup->sm_peer_confirm, 0, 16); 3578 } 3579 #endif 3580 // notify client to hide shown passkey 3581 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3582 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3583 } 3584 3585 // handle user cancel pairing? 3586 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3587 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3588 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3589 break; 3590 } 3591 3592 // wait for user action? 3593 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3594 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3595 break; 3596 } 3597 3598 // calculate and send local_confirm 3599 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3600 break; 3601 3602 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3603 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3604 sm_pdu_received_in_wrong_state(sm_conn); 3605 break;; 3606 } 3607 3608 // received random value 3609 reverse_128(&packet[1], setup->sm_peer_random); 3610 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3611 break; 3612 #endif 3613 3614 case SM_PH3_RECEIVE_KEYS: 3615 switch(sm_pdu_code){ 3616 case SM_CODE_ENCRYPTION_INFORMATION: 3617 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3618 reverse_128(&packet[1], setup->sm_peer_ltk); 3619 break; 3620 3621 case SM_CODE_MASTER_IDENTIFICATION: 3622 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3623 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3624 reverse_64(&packet[3], setup->sm_peer_rand); 3625 break; 3626 3627 case SM_CODE_IDENTITY_INFORMATION: 3628 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3629 reverse_128(&packet[1], setup->sm_peer_irk); 3630 break; 3631 3632 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3633 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3634 setup->sm_peer_addr_type = packet[1]; 3635 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3636 break; 3637 3638 case SM_CODE_SIGNING_INFORMATION: 3639 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3640 reverse_128(&packet[1], setup->sm_peer_csrk); 3641 break; 3642 default: 3643 // Unexpected PDU 3644 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3645 break; 3646 } 3647 // done with key distribution? 3648 if (sm_key_distribution_all_received(sm_conn)){ 3649 3650 sm_key_distribution_handle_all_received(sm_conn); 3651 3652 if (IS_RESPONDER(sm_conn->sm_role)){ 3653 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3654 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3655 } else { 3656 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3657 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3658 sm_done_for_handle(sm_conn->sm_handle); 3659 } 3660 } else { 3661 if (setup->sm_use_secure_connections){ 3662 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3663 } else { 3664 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3665 } 3666 } 3667 } 3668 break; 3669 default: 3670 // Unexpected PDU 3671 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3672 break; 3673 } 3674 3675 // try to send preparared packet 3676 sm_run(); 3677 } 3678 3679 // Security Manager Client API 3680 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3681 sm_get_oob_data = get_oob_data_callback; 3682 } 3683 3684 void sm_register_sc_oob_data_callback( int (*get_sc_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random)){ 3685 sm_get_sc_oob_data = get_sc_oob_data_callback; 3686 } 3687 3688 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3689 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3690 } 3691 3692 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3693 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3694 } 3695 3696 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3697 sm_min_encryption_key_size = min_size; 3698 sm_max_encryption_key_size = max_size; 3699 } 3700 3701 void sm_set_authentication_requirements(uint8_t auth_req){ 3702 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3703 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3704 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3705 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3706 } 3707 #endif 3708 sm_auth_req = auth_req; 3709 } 3710 3711 void sm_set_io_capabilities(io_capability_t io_capability){ 3712 sm_io_capabilities = io_capability; 3713 } 3714 3715 #ifdef ENABLE_LE_PERIPHERAL 3716 void sm_set_request_security(int enable){ 3717 sm_slave_request_security = enable; 3718 } 3719 #endif 3720 3721 void sm_set_er(sm_key_t er){ 3722 memcpy(sm_persistent_er, er, 16); 3723 } 3724 3725 void sm_set_ir(sm_key_t ir){ 3726 memcpy(sm_persistent_ir, ir, 16); 3727 } 3728 3729 // Testing support only 3730 void sm_test_set_irk(sm_key_t irk){ 3731 memcpy(sm_persistent_irk, irk, 16); 3732 sm_persistent_irk_ready = 1; 3733 } 3734 3735 void sm_test_use_fixed_local_csrk(void){ 3736 test_use_fixed_local_csrk = 1; 3737 } 3738 3739 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3740 static void sm_ec_generated(void * arg){ 3741 UNUSED(arg); 3742 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3743 // trigger pairing if pending for ec key 3744 sm_run(); 3745 } 3746 static void sm_ec_generate_new_key(void){ 3747 log_info("sm: generate new ec key"); 3748 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3749 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3750 } 3751 #endif 3752 3753 #ifdef ENABLE_TESTING_SUPPORT 3754 void sm_test_set_pairing_failure(int reason){ 3755 test_pairing_failure = reason; 3756 } 3757 #endif 3758 3759 void sm_init(void){ 3760 // set some (BTstack default) ER and IR 3761 int i; 3762 sm_key_t er; 3763 sm_key_t ir; 3764 for (i=0;i<16;i++){ 3765 er[i] = 0x30 + i; 3766 ir[i] = 0x90 + i; 3767 } 3768 sm_set_er(er); 3769 sm_set_ir(ir); 3770 // defaults 3771 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3772 | SM_STK_GENERATION_METHOD_OOB 3773 | SM_STK_GENERATION_METHOD_PASSKEY 3774 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3775 3776 sm_max_encryption_key_size = 16; 3777 sm_min_encryption_key_size = 7; 3778 3779 sm_fixed_passkey_in_display_role = 0xffffffff; 3780 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3781 3782 #ifdef USE_CMAC_ENGINE 3783 sm_cmac_active = 0; 3784 #endif 3785 dkg_state = DKG_W4_WORKING; 3786 rau_state = RAU_IDLE; 3787 sm_aes128_state = SM_AES128_IDLE; 3788 sm_address_resolution_test = -1; // no private address to resolve yet 3789 sm_address_resolution_ah_calculation_active = 0; 3790 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3791 sm_address_resolution_general_queue = NULL; 3792 3793 gap_random_adress_update_period = 15 * 60 * 1000L; 3794 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3795 3796 test_use_fixed_local_csrk = 0; 3797 3798 // register for HCI Events from HCI 3799 hci_event_callback_registration.callback = &sm_event_packet_handler; 3800 hci_add_event_handler(&hci_event_callback_registration); 3801 3802 // 3803 btstack_crypto_init(); 3804 3805 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3806 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3807 3808 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3809 sm_ec_generate_new_key(); 3810 #endif 3811 } 3812 3813 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3814 sm_fixed_passkey_in_display_role = passkey; 3815 } 3816 3817 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3818 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3819 } 3820 3821 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3822 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3823 if (!hci_con) return NULL; 3824 return &hci_con->sm_connection; 3825 } 3826 3827 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3828 switch (sm_conn->sm_engine_state){ 3829 case SM_GENERAL_IDLE: 3830 case SM_RESPONDER_IDLE: 3831 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3832 sm_run(); 3833 break; 3834 default: 3835 break; 3836 } 3837 } 3838 3839 /** 3840 * @brief Trigger Security Request 3841 */ 3842 void sm_send_security_request(hci_con_handle_t con_handle){ 3843 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3844 if (!sm_conn) return; 3845 sm_send_security_request_for_connection(sm_conn); 3846 } 3847 3848 // request pairing 3849 void sm_request_pairing(hci_con_handle_t con_handle){ 3850 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3851 if (!sm_conn) return; // wrong connection 3852 3853 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3854 if (IS_RESPONDER(sm_conn->sm_role)){ 3855 sm_send_security_request_for_connection(sm_conn); 3856 } else { 3857 // used as a trigger to start central/master/initiator security procedures 3858 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3859 uint8_t ltk[16]; 3860 switch (sm_conn->sm_irk_lookup_state){ 3861 case IRK_LOOKUP_SUCCEEDED: 3862 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 3863 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3864 int have_ltk = !sm_is_null_key(ltk); 3865 log_info("have ltk %u", have_ltk); 3866 // trigger 'pairing complete' event on encryption change 3867 sm_conn->sm_pairing_requested = 1; 3868 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3869 break; 3870 #endif 3871 /* explicit fall-through */ 3872 3873 case IRK_LOOKUP_FAILED: 3874 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3875 break; 3876 default: 3877 log_info("irk lookup pending"); 3878 sm_conn->sm_pairing_requested = 1; 3879 break; 3880 } 3881 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3882 sm_conn->sm_pairing_requested = 1; 3883 } 3884 } 3885 sm_run(); 3886 } 3887 3888 // called by client app on authorization request 3889 void sm_authorization_decline(hci_con_handle_t con_handle){ 3890 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3891 if (!sm_conn) return; // wrong connection 3892 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3893 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3894 } 3895 3896 void sm_authorization_grant(hci_con_handle_t con_handle){ 3897 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3898 if (!sm_conn) return; // wrong connection 3899 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3900 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3901 } 3902 3903 // GAP Bonding API 3904 3905 void sm_bonding_decline(hci_con_handle_t con_handle){ 3906 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3907 if (!sm_conn) return; // wrong connection 3908 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3909 log_info("decline, state %u", sm_conn->sm_engine_state); 3910 switch(sm_conn->sm_engine_state){ 3911 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3912 case SM_SC_W4_USER_RESPONSE: 3913 case SM_SC_W4_CONFIRMATION: 3914 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3915 #endif 3916 case SM_PH1_W4_USER_RESPONSE: 3917 switch (setup->sm_stk_generation_method){ 3918 case PK_RESP_INPUT: 3919 case PK_INIT_INPUT: 3920 case PK_BOTH_INPUT: 3921 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 3922 break; 3923 case NUMERIC_COMPARISON: 3924 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3925 break; 3926 case JUST_WORKS: 3927 case OOB: 3928 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3929 break; 3930 } 3931 break; 3932 default: 3933 break; 3934 } 3935 sm_run(); 3936 } 3937 3938 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3939 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3940 if (!sm_conn) return; // wrong connection 3941 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3942 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3943 if (setup->sm_use_secure_connections){ 3944 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3945 } else { 3946 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3947 } 3948 } 3949 3950 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3951 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3952 sm_sc_prepare_dhkey_check(sm_conn); 3953 } 3954 #endif 3955 3956 sm_run(); 3957 } 3958 3959 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3960 // for now, it's the same 3961 sm_just_works_confirm(con_handle); 3962 } 3963 3964 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3965 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3966 if (!sm_conn) return; // wrong connection 3967 sm_reset_tk(); 3968 big_endian_store_32(setup->sm_tk, 12, passkey); 3969 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3970 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3971 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3972 } 3973 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3974 memcpy(setup->sm_ra, setup->sm_tk, 16); 3975 memcpy(setup->sm_rb, setup->sm_tk, 16); 3976 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3977 sm_sc_start_calculating_local_confirm(sm_conn); 3978 } 3979 #endif 3980 sm_run(); 3981 } 3982 3983 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3984 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3985 if (!sm_conn) return; // wrong connection 3986 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3987 uint8_t num_actions = setup->sm_keypress_notification >> 5; 3988 uint8_t flags = setup->sm_keypress_notification & 0x1f; 3989 switch (action){ 3990 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 3991 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 3992 flags |= (1 << action); 3993 break; 3994 case SM_KEYPRESS_PASSKEY_CLEARED: 3995 // clear counter, keypress & erased flags + set passkey cleared 3996 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 3997 break; 3998 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 3999 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4000 // erase actions queued 4001 num_actions--; 4002 if (num_actions == 0){ 4003 // clear counter, keypress & erased flags 4004 flags &= 0x19; 4005 } 4006 break; 4007 } 4008 num_actions++; 4009 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4010 break; 4011 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4012 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4013 // enter actions queued 4014 num_actions--; 4015 if (num_actions == 0){ 4016 // clear counter, keypress & erased flags 4017 flags &= 0x19; 4018 } 4019 break; 4020 } 4021 num_actions++; 4022 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4023 break; 4024 default: 4025 break; 4026 } 4027 setup->sm_keypress_notification = (num_actions << 5) | flags; 4028 sm_run(); 4029 } 4030 4031 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4032 static void sm_handle_random_result_oob(void * arg){ 4033 UNUSED(arg); 4034 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4035 sm_run(); 4036 } 4037 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4038 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4039 sm_sc_oob_callback = callback; 4040 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4041 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4042 return 0; 4043 } 4044 #endif 4045 4046 /** 4047 * @brief Identify device in LE Device DB 4048 * @param handle 4049 * @returns index from le_device_db or -1 if not found/identified 4050 */ 4051 int sm_le_device_index(hci_con_handle_t con_handle ){ 4052 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4053 if (!sm_conn) return -1; 4054 return sm_conn->sm_le_db_index; 4055 } 4056 4057 static int gap_random_address_type_requires_updates(void){ 4058 switch (gap_random_adress_type){ 4059 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4060 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4061 return 0; 4062 default: 4063 return 1; 4064 } 4065 } 4066 4067 static uint8_t own_address_type(void){ 4068 switch (gap_random_adress_type){ 4069 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4070 return BD_ADDR_TYPE_LE_PUBLIC; 4071 default: 4072 return BD_ADDR_TYPE_LE_RANDOM; 4073 } 4074 } 4075 4076 // GAP LE API 4077 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4078 gap_random_address_update_stop(); 4079 gap_random_adress_type = random_address_type; 4080 hci_le_set_own_address_type(own_address_type()); 4081 if (!gap_random_address_type_requires_updates()) return; 4082 gap_random_address_update_start(); 4083 gap_random_address_trigger(); 4084 } 4085 4086 gap_random_address_type_t gap_random_address_get_mode(void){ 4087 return gap_random_adress_type; 4088 } 4089 4090 void gap_random_address_set_update_period(int period_ms){ 4091 gap_random_adress_update_period = period_ms; 4092 if (!gap_random_address_type_requires_updates()) return; 4093 gap_random_address_update_stop(); 4094 gap_random_address_update_start(); 4095 } 4096 4097 void gap_random_address_set(bd_addr_t addr){ 4098 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4099 memcpy(sm_random_address, addr, 6); 4100 rau_state = RAU_SET_ADDRESS; 4101 sm_run(); 4102 } 4103 4104 #ifdef ENABLE_LE_PERIPHERAL 4105 /* 4106 * @brief Set Advertisement Paramters 4107 * @param adv_int_min 4108 * @param adv_int_max 4109 * @param adv_type 4110 * @param direct_address_type 4111 * @param direct_address 4112 * @param channel_map 4113 * @param filter_policy 4114 * 4115 * @note own_address_type is used from gap_random_address_set_mode 4116 */ 4117 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4118 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4119 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4120 direct_address_typ, direct_address, channel_map, filter_policy); 4121 } 4122 #endif 4123 4124 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4125 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4126 // wrong connection 4127 if (!sm_conn) return 0; 4128 // already encrypted 4129 if (sm_conn->sm_connection_encrypted) return 0; 4130 // only central can re-encrypt 4131 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4132 // irk status? 4133 switch(sm_conn->sm_irk_lookup_state){ 4134 case IRK_LOOKUP_FAILED: 4135 // done, cannot setup encryption 4136 return 0; 4137 case IRK_LOOKUP_SUCCEEDED: 4138 break; 4139 default: 4140 // IR Lookup pending 4141 return 1; 4142 } 4143 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4144 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4145 } 4146