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_W4_WORKING, 97 RAU_IDLE, 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_W4_RANDOM; 551 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 8, &sm_handle_random_result_rau, NULL); 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 // have ltk -> start encryption 1155 if (have_ltk){ 1156 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1157 break; 1158 } 1159 // pairint_request -> send pairing request 1160 if (pairing_need){ 1161 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1162 break; 1163 } 1164 #endif 1165 break; 1166 case ADDRESS_RESOLUTION_FAILED: 1167 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1168 if (sm_connection->sm_role) { 1169 // LTK request received before, IRK required -> negative LTK reply 1170 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1171 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1172 } 1173 break; 1174 } 1175 #ifdef ENABLE_LE_CENTRAL 1176 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1177 sm_connection->sm_security_request_received = 0; 1178 sm_connection->sm_pairing_requested = 0; 1179 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1180 #endif 1181 break; 1182 } 1183 break; 1184 default: 1185 break; 1186 } 1187 1188 switch (event){ 1189 case ADDRESS_RESOLUTION_SUCEEDED: 1190 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1191 break; 1192 case ADDRESS_RESOLUTION_FAILED: 1193 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1194 break; 1195 } 1196 } 1197 1198 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1199 1200 int le_db_index = -1; 1201 1202 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1203 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1204 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1205 & SM_AUTHREQ_BONDING ) != 0; 1206 1207 if (bonding_enabed){ 1208 1209 // lookup device based on IRK 1210 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1211 int i; 1212 for (i=0; i < le_device_db_max_count(); i++){ 1213 sm_key_t irk; 1214 bd_addr_t address; 1215 int address_type = BD_ADDR_TYPE_UNKNOWN; 1216 le_device_db_info(i, &address_type, address, irk); 1217 // check if valid entry retrieved 1218 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1219 // compare IRK 1220 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1221 1222 log_info("sm: device found for IRK, updating"); 1223 le_db_index = i; 1224 break; 1225 } 1226 } else { 1227 // assert IRK is set to zero 1228 memset(setup->sm_peer_irk, 0, 16); 1229 } 1230 1231 // if not found, lookup via public address if possible 1232 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1233 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1234 int i; 1235 for (i=0; i < le_device_db_max_count(); i++){ 1236 bd_addr_t address; 1237 int address_type; 1238 le_device_db_info(i, &address_type, address, NULL); 1239 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1240 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1241 log_info("sm: device found for public address, updating"); 1242 le_db_index = i; 1243 break; 1244 } 1245 } 1246 } 1247 1248 // if not found, add to db 1249 if (le_db_index < 0) { 1250 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1251 } 1252 1253 if (le_db_index >= 0){ 1254 1255 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1256 1257 #ifdef ENABLE_LE_SIGNED_WRITE 1258 // store local CSRK 1259 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1260 log_info("sm: store local CSRK"); 1261 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1262 le_device_db_local_counter_set(le_db_index, 0); 1263 } 1264 1265 // store remote CSRK 1266 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1267 log_info("sm: store remote CSRK"); 1268 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1269 le_device_db_remote_counter_set(le_db_index, 0); 1270 } 1271 #endif 1272 // store encryption information for secure connections: LTK generated by ECDH 1273 if (setup->sm_use_secure_connections){ 1274 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1275 uint8_t zero_rand[8]; 1276 memset(zero_rand, 0, 8); 1277 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1278 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1279 } 1280 1281 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1282 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1283 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1284 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1285 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1286 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1287 1288 } 1289 } 1290 } else { 1291 log_info("Ignoring received keys, bonding not enabled"); 1292 } 1293 1294 // keep le_db_index 1295 sm_conn->sm_le_db_index = le_db_index; 1296 } 1297 1298 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1299 setup->sm_pairing_failed_reason = reason; 1300 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1301 } 1302 1303 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1304 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1305 } 1306 1307 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1308 1309 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1310 static int sm_passkey_used(stk_generation_method_t method); 1311 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1312 1313 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1314 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1315 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1316 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1317 } else { 1318 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1319 } 1320 } 1321 1322 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1323 if (IS_RESPONDER(sm_conn->sm_role)){ 1324 // Responder 1325 if (setup->sm_stk_generation_method == OOB){ 1326 // generate Nb 1327 log_info("Generate Nb"); 1328 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1329 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1330 } else { 1331 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1332 } 1333 } else { 1334 // Initiator role 1335 switch (setup->sm_stk_generation_method){ 1336 case JUST_WORKS: 1337 sm_sc_prepare_dhkey_check(sm_conn); 1338 break; 1339 1340 case NUMERIC_COMPARISON: 1341 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1342 break; 1343 case PK_INIT_INPUT: 1344 case PK_RESP_INPUT: 1345 case PK_BOTH_INPUT: 1346 if (setup->sm_passkey_bit < 20) { 1347 sm_sc_start_calculating_local_confirm(sm_conn); 1348 } else { 1349 sm_sc_prepare_dhkey_check(sm_conn); 1350 } 1351 break; 1352 case OOB: 1353 sm_sc_prepare_dhkey_check(sm_conn); 1354 break; 1355 } 1356 } 1357 } 1358 1359 static void sm_sc_cmac_done(uint8_t * hash){ 1360 log_info("sm_sc_cmac_done: "); 1361 log_info_hexdump(hash, 16); 1362 1363 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1364 sm_sc_oob_state = SM_SC_OOB_IDLE; 1365 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1366 return; 1367 } 1368 1369 sm_connection_t * sm_conn = sm_cmac_connection; 1370 sm_cmac_connection = NULL; 1371 #ifdef ENABLE_CLASSIC 1372 link_key_type_t link_key_type; 1373 #endif 1374 1375 switch (sm_conn->sm_engine_state){ 1376 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1377 memcpy(setup->sm_local_confirm, hash, 16); 1378 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1379 break; 1380 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1381 // check 1382 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1383 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1384 break; 1385 } 1386 sm_sc_state_after_receiving_random(sm_conn); 1387 break; 1388 case SM_SC_W4_CALCULATE_G2: { 1389 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1390 big_endian_store_32(setup->sm_tk, 12, vab); 1391 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1392 sm_trigger_user_response(sm_conn); 1393 break; 1394 } 1395 case SM_SC_W4_CALCULATE_F5_SALT: 1396 memcpy(setup->sm_t, hash, 16); 1397 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1398 break; 1399 case SM_SC_W4_CALCULATE_F5_MACKEY: 1400 memcpy(setup->sm_mackey, hash, 16); 1401 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1402 break; 1403 case SM_SC_W4_CALCULATE_F5_LTK: 1404 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1405 // Errata Service Release to the Bluetooth Specification: ESR09 1406 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1407 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1408 memcpy(setup->sm_ltk, hash, 16); 1409 memcpy(setup->sm_local_ltk, hash, 16); 1410 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1411 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1412 break; 1413 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1414 memcpy(setup->sm_local_dhkey_check, hash, 16); 1415 if (IS_RESPONDER(sm_conn->sm_role)){ 1416 // responder 1417 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1418 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1419 } else { 1420 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1421 } 1422 } else { 1423 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1424 } 1425 break; 1426 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1427 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1428 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1429 break; 1430 } 1431 if (IS_RESPONDER(sm_conn->sm_role)){ 1432 // responder 1433 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1434 } else { 1435 // initiator 1436 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1437 } 1438 break; 1439 case SM_SC_W4_CALCULATE_H6_ILK: 1440 memcpy(setup->sm_t, hash, 16); 1441 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1442 break; 1443 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1444 #ifdef ENABLE_CLASSIC 1445 reverse_128(hash, setup->sm_t); 1446 link_key_type = sm_conn->sm_connection_authenticated ? 1447 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1448 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1449 if (IS_RESPONDER(sm_conn->sm_role)){ 1450 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1451 } else { 1452 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1453 } 1454 #endif 1455 if (IS_RESPONDER(sm_conn->sm_role)){ 1456 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1457 } else { 1458 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1459 } 1460 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1461 sm_done_for_handle(sm_conn->sm_handle); 1462 break; 1463 default: 1464 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1465 break; 1466 } 1467 sm_run(); 1468 } 1469 1470 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){ 1471 const uint16_t message_len = 65; 1472 sm_cmac_connection = sm_conn; 1473 memcpy(sm_cmac_sc_buffer, u, 32); 1474 memcpy(sm_cmac_sc_buffer+32, v, 32); 1475 sm_cmac_sc_buffer[64] = z; 1476 log_info("f4 key"); 1477 log_info_hexdump(x, 16); 1478 log_info("f4 message"); 1479 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1480 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1481 } 1482 1483 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1484 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1485 static const uint8_t f5_length[] = { 0x01, 0x00}; 1486 1487 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1488 log_info("f5_calculate_salt"); 1489 // calculate salt for f5 1490 const uint16_t message_len = 32; 1491 sm_cmac_connection = sm_conn; 1492 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1493 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1494 } 1495 1496 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){ 1497 const uint16_t message_len = 53; 1498 sm_cmac_connection = sm_conn; 1499 1500 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1501 sm_cmac_sc_buffer[0] = 0; 1502 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1503 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1504 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1505 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1506 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1507 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1508 log_info("f5 key"); 1509 log_info_hexdump(t, 16); 1510 log_info("f5 message for MacKey"); 1511 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1512 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1513 } 1514 1515 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1516 sm_key56_t bd_addr_master, bd_addr_slave; 1517 bd_addr_master[0] = setup->sm_m_addr_type; 1518 bd_addr_slave[0] = setup->sm_s_addr_type; 1519 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1520 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1521 if (IS_RESPONDER(sm_conn->sm_role)){ 1522 // responder 1523 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1524 } else { 1525 // initiator 1526 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1527 } 1528 } 1529 1530 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1531 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1532 const uint16_t message_len = 53; 1533 sm_cmac_connection = sm_conn; 1534 sm_cmac_sc_buffer[0] = 1; 1535 // 1..52 setup before 1536 log_info("f5 key"); 1537 log_info_hexdump(t, 16); 1538 log_info("f5 message for LTK"); 1539 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1540 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1541 } 1542 1543 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1544 f5_ltk(sm_conn, setup->sm_t); 1545 } 1546 1547 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){ 1548 const uint16_t message_len = 65; 1549 sm_cmac_connection = sm_conn; 1550 memcpy(sm_cmac_sc_buffer, n1, 16); 1551 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1552 memcpy(sm_cmac_sc_buffer+32, r, 16); 1553 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1554 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1555 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1556 log_info("f6 key"); 1557 log_info_hexdump(w, 16); 1558 log_info("f6 message"); 1559 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1560 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1561 } 1562 1563 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1564 // - U is 256 bits 1565 // - V is 256 bits 1566 // - X is 128 bits 1567 // - Y is 128 bits 1568 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){ 1569 const uint16_t message_len = 80; 1570 sm_cmac_connection = sm_conn; 1571 memcpy(sm_cmac_sc_buffer, u, 32); 1572 memcpy(sm_cmac_sc_buffer+32, v, 32); 1573 memcpy(sm_cmac_sc_buffer+64, y, 16); 1574 log_info("g2 key"); 1575 log_info_hexdump(x, 16); 1576 log_info("g2 message"); 1577 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1578 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1579 } 1580 1581 static void g2_calculate(sm_connection_t * sm_conn) { 1582 // calc Va if numeric comparison 1583 if (IS_RESPONDER(sm_conn->sm_role)){ 1584 // responder 1585 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1586 } else { 1587 // initiator 1588 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1589 } 1590 } 1591 1592 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1593 uint8_t z = 0; 1594 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1595 // some form of passkey 1596 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1597 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1598 setup->sm_passkey_bit++; 1599 } 1600 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1601 } 1602 1603 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1604 // OOB 1605 if (setup->sm_stk_generation_method == OOB){ 1606 if (IS_RESPONDER(sm_conn->sm_role)){ 1607 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1608 } else { 1609 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1610 } 1611 return; 1612 } 1613 1614 uint8_t z = 0; 1615 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1616 // some form of passkey 1617 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1618 // sm_passkey_bit was increased before sending confirm value 1619 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1620 } 1621 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1622 } 1623 1624 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1625 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1626 1627 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1628 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1629 return; 1630 } else { 1631 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1632 } 1633 } 1634 1635 static void sm_sc_dhkey_calculated(void * arg){ 1636 sm_connection_t * sm_conn = (sm_connection_t *) arg; 1637 log_info("dhkey"); 1638 log_info_hexdump(&setup->sm_dhkey[0], 32); 1639 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1640 // trigger next step 1641 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1642 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1643 } 1644 sm_run(); 1645 } 1646 1647 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1648 // calculate DHKCheck 1649 sm_key56_t bd_addr_master, bd_addr_slave; 1650 bd_addr_master[0] = setup->sm_m_addr_type; 1651 bd_addr_slave[0] = setup->sm_s_addr_type; 1652 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1653 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1654 uint8_t iocap_a[3]; 1655 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1656 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1657 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1658 uint8_t iocap_b[3]; 1659 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1660 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1661 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1662 if (IS_RESPONDER(sm_conn->sm_role)){ 1663 // responder 1664 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); 1665 } else { 1666 // initiator 1667 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); 1668 } 1669 } 1670 1671 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1672 // validate E = f6() 1673 sm_key56_t bd_addr_master, bd_addr_slave; 1674 bd_addr_master[0] = setup->sm_m_addr_type; 1675 bd_addr_slave[0] = setup->sm_s_addr_type; 1676 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1677 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1678 1679 uint8_t iocap_a[3]; 1680 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1681 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1682 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1683 uint8_t iocap_b[3]; 1684 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1685 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1686 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1687 if (IS_RESPONDER(sm_conn->sm_role)){ 1688 // responder 1689 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); 1690 } else { 1691 // initiator 1692 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); 1693 } 1694 } 1695 1696 1697 // 1698 // Link Key Conversion Function h6 1699 // 1700 // h6(W, keyID) = AES-CMACW(keyID) 1701 // - W is 128 bits 1702 // - keyID is 32 bits 1703 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1704 const uint16_t message_len = 4; 1705 sm_cmac_connection = sm_conn; 1706 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1707 log_info("h6 key"); 1708 log_info_hexdump(w, 16); 1709 log_info("h6 message"); 1710 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1711 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1712 } 1713 1714 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1715 // Errata Service Release to the Bluetooth Specification: ESR09 1716 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1717 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1718 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1719 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1720 } 1721 1722 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1723 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1724 } 1725 1726 #endif 1727 1728 // key management legacy connections: 1729 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1730 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1731 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1732 // - responder reconnects: responder uses LTK receveived from master 1733 1734 // key management secure connections: 1735 // - both devices store same LTK from ECDH key exchange. 1736 1737 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1738 static void sm_load_security_info(sm_connection_t * sm_connection){ 1739 int encryption_key_size; 1740 int authenticated; 1741 int authorized; 1742 1743 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1744 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1745 &encryption_key_size, &authenticated, &authorized); 1746 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1747 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1748 sm_connection->sm_connection_authenticated = authenticated; 1749 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1750 } 1751 #endif 1752 1753 #ifdef ENABLE_LE_PERIPHERAL 1754 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1755 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1756 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1757 // re-establish used key encryption size 1758 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1759 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1760 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1761 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1762 log_info("sm: received ltk request with key size %u, authenticated %u", 1763 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1764 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1765 sm_run(); 1766 } 1767 #endif 1768 1769 static void sm_run(void){ 1770 1771 btstack_linked_list_iterator_t it; 1772 1773 // assert that stack has already bootet 1774 if (hci_get_state() != HCI_STATE_WORKING) return; 1775 1776 // assert that we can send at least commands 1777 if (!hci_can_send_command_packet_now()) return; 1778 1779 // 1780 // non-connection related behaviour 1781 // 1782 1783 // distributed key generation 1784 switch (dkg_state){ 1785 case DKG_CALC_IRK: 1786 // already busy? 1787 if (sm_aes128_state == SM_AES128_IDLE) { 1788 log_info("DKG_CALC_IRK started"); 1789 // IRK = d1(IR, 1, 0) 1790 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1791 sm_aes128_state = SM_AES128_ACTIVE; 1792 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1793 return; 1794 } 1795 break; 1796 case DKG_CALC_DHK: 1797 // already busy? 1798 if (sm_aes128_state == SM_AES128_IDLE) { 1799 log_info("DKG_CALC_DHK started"); 1800 // DHK = d1(IR, 3, 0) 1801 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1802 sm_aes128_state = SM_AES128_ACTIVE; 1803 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1804 return; 1805 } 1806 break; 1807 default: 1808 break; 1809 } 1810 1811 // random address updates 1812 switch (rau_state){ 1813 case RAU_GET_ENC: 1814 // already busy? 1815 if (sm_aes128_state == SM_AES128_IDLE) { 1816 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1817 sm_aes128_state = SM_AES128_ACTIVE; 1818 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1819 return; 1820 } 1821 break; 1822 case RAU_SET_ADDRESS: 1823 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1824 rau_state = RAU_IDLE; 1825 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1826 return; 1827 default: 1828 break; 1829 } 1830 1831 // CSRK Lookup 1832 // -- if csrk lookup ready, find connection that require csrk lookup 1833 if (sm_address_resolution_idle()){ 1834 hci_connections_get_iterator(&it); 1835 while(btstack_linked_list_iterator_has_next(&it)){ 1836 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1837 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1838 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1839 // and start lookup 1840 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); 1841 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1842 break; 1843 } 1844 } 1845 } 1846 1847 // -- if csrk lookup ready, resolved addresses for received addresses 1848 if (sm_address_resolution_idle()) { 1849 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1850 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1851 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1852 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1853 btstack_memory_sm_lookup_entry_free(entry); 1854 } 1855 } 1856 1857 // -- Continue with CSRK device lookup by public or resolvable private address 1858 if (!sm_address_resolution_idle()){ 1859 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1860 while (sm_address_resolution_test < le_device_db_max_count()){ 1861 int addr_type; 1862 bd_addr_t addr; 1863 sm_key_t irk; 1864 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1865 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1866 1867 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1868 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1869 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1870 break; 1871 } 1872 1873 if (sm_address_resolution_addr_type == 0){ 1874 sm_address_resolution_test++; 1875 continue; 1876 } 1877 1878 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1879 1880 log_info("LE Device Lookup: calculate AH"); 1881 log_info_key("IRK", irk); 1882 1883 memcpy(sm_aes128_key, irk, 16); 1884 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1885 sm_address_resolution_ah_calculation_active = 1; 1886 sm_aes128_state = SM_AES128_ACTIVE; 1887 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1888 return; 1889 } 1890 1891 if (sm_address_resolution_test >= le_device_db_max_count()){ 1892 log_info("LE Device Lookup: not found"); 1893 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1894 } 1895 } 1896 1897 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1898 switch (sm_sc_oob_state){ 1899 case SM_SC_OOB_W2_CALC_CONFIRM: 1900 if (!sm_cmac_ready()) break; 1901 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1902 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1903 return; 1904 default: 1905 break; 1906 } 1907 #endif 1908 1909 // assert that we can send at least commands - cmd might have been sent by crypto engine 1910 if (!hci_can_send_command_packet_now()) return; 1911 1912 // handle basic actions that don't requires the full context 1913 hci_connections_get_iterator(&it); 1914 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1915 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1916 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1917 switch(sm_connection->sm_engine_state){ 1918 // responder side 1919 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1920 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1921 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1922 return; 1923 1924 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1925 case SM_SC_RECEIVED_LTK_REQUEST: 1926 switch (sm_connection->sm_irk_lookup_state){ 1927 case IRK_LOOKUP_FAILED: 1928 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1929 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1930 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1931 return; 1932 default: 1933 break; 1934 } 1935 break; 1936 #endif 1937 default: 1938 break; 1939 } 1940 } 1941 1942 // 1943 // active connection handling 1944 // -- use loop to handle next connection if lock on setup context is released 1945 1946 while (1) { 1947 1948 // Find connections that requires setup context and make active if no other is locked 1949 hci_connections_get_iterator(&it); 1950 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1951 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1952 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1953 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1954 int done = 1; 1955 int err; 1956 UNUSED(err); 1957 1958 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1959 // assert ec key is ready 1960 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 1961 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 1962 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 1963 sm_ec_generate_new_key(); 1964 } 1965 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 1966 continue; 1967 } 1968 } 1969 #endif 1970 1971 switch (sm_connection->sm_engine_state) { 1972 #ifdef ENABLE_LE_PERIPHERAL 1973 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1974 // send packet if possible, 1975 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1976 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1977 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1978 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1979 } else { 1980 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1981 } 1982 // don't lock sxetup context yet 1983 done = 0; 1984 break; 1985 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1986 sm_reset_setup(); 1987 sm_init_setup(sm_connection); 1988 // recover pairing request 1989 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1990 err = sm_stk_generation_init(sm_connection); 1991 1992 #ifdef ENABLE_TESTING_SUPPORT 1993 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 1994 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 1995 err = test_pairing_failure; 1996 } 1997 #endif 1998 if (err){ 1999 setup->sm_pairing_failed_reason = err; 2000 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2001 break; 2002 } 2003 sm_timeout_start(sm_connection); 2004 // generate random number first, if we need to show passkey 2005 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2006 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2007 break; 2008 } 2009 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2010 break; 2011 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2012 sm_reset_setup(); 2013 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2014 break; 2015 2016 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2017 case SM_SC_RECEIVED_LTK_REQUEST: 2018 switch (sm_connection->sm_irk_lookup_state){ 2019 case IRK_LOOKUP_SUCCEEDED: 2020 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2021 // start using context by loading security info 2022 sm_reset_setup(); 2023 sm_load_security_info(sm_connection); 2024 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2025 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2026 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2027 break; 2028 } 2029 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2030 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2031 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2032 // don't lock setup context yet 2033 return; 2034 default: 2035 // just wait until IRK lookup is completed 2036 // don't lock setup context yet 2037 done = 0; 2038 break; 2039 } 2040 break; 2041 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2042 #endif /* ENABLE_LE_PERIPHERAL */ 2043 2044 #ifdef ENABLE_LE_CENTRAL 2045 case SM_INITIATOR_PH0_HAS_LTK: 2046 sm_reset_setup(); 2047 sm_load_security_info(sm_connection); 2048 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2049 break; 2050 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2051 sm_reset_setup(); 2052 sm_init_setup(sm_connection); 2053 sm_timeout_start(sm_connection); 2054 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2055 break; 2056 #endif 2057 2058 default: 2059 done = 0; 2060 break; 2061 } 2062 if (done){ 2063 sm_active_connection_handle = sm_connection->sm_handle; 2064 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); 2065 } 2066 } 2067 2068 // 2069 // active connection handling 2070 // 2071 2072 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2073 2074 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2075 if (!connection) { 2076 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2077 return; 2078 } 2079 2080 // assert that we could send a SM PDU - not needed for all of the following 2081 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2082 log_info("cannot send now, requesting can send now event"); 2083 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2084 return; 2085 } 2086 2087 // send keypress notifications 2088 if (setup->sm_keypress_notification){ 2089 int i; 2090 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2091 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2092 uint8_t action = 0; 2093 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2094 if (flags & (1<<i)){ 2095 int clear_flag = 1; 2096 switch (i){ 2097 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2098 case SM_KEYPRESS_PASSKEY_CLEARED: 2099 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2100 default: 2101 break; 2102 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2103 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2104 num_actions--; 2105 clear_flag = num_actions == 0; 2106 break; 2107 } 2108 if (clear_flag){ 2109 flags &= ~(1<<i); 2110 } 2111 action = i; 2112 break; 2113 } 2114 } 2115 setup->sm_keypress_notification = (num_actions << 5) | flags; 2116 2117 // send keypress notification 2118 uint8_t buffer[2]; 2119 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2120 buffer[1] = action; 2121 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2122 2123 // try 2124 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2125 return; 2126 } 2127 2128 int key_distribution_flags; 2129 UNUSED(key_distribution_flags); 2130 2131 log_info("sm_run: state %u", connection->sm_engine_state); 2132 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2133 log_info("sm_run // cannot send"); 2134 } 2135 switch (connection->sm_engine_state){ 2136 2137 // general 2138 case SM_GENERAL_SEND_PAIRING_FAILED: { 2139 uint8_t buffer[2]; 2140 buffer[0] = SM_CODE_PAIRING_FAILED; 2141 buffer[1] = setup->sm_pairing_failed_reason; 2142 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2143 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2144 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2145 sm_done_for_handle(connection->sm_handle); 2146 break; 2147 } 2148 2149 // responding state 2150 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2151 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2152 if (!sm_cmac_ready()) break; 2153 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2154 sm_sc_calculate_local_confirm(connection); 2155 break; 2156 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2157 if (!sm_cmac_ready()) break; 2158 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2159 sm_sc_calculate_remote_confirm(connection); 2160 break; 2161 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2162 if (!sm_cmac_ready()) break; 2163 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2164 sm_sc_calculate_f6_for_dhkey_check(connection); 2165 break; 2166 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2167 if (!sm_cmac_ready()) break; 2168 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2169 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2170 break; 2171 case SM_SC_W2_CALCULATE_F5_SALT: 2172 if (!sm_cmac_ready()) break; 2173 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2174 f5_calculate_salt(connection); 2175 break; 2176 case SM_SC_W2_CALCULATE_F5_MACKEY: 2177 if (!sm_cmac_ready()) break; 2178 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2179 f5_calculate_mackey(connection); 2180 break; 2181 case SM_SC_W2_CALCULATE_F5_LTK: 2182 if (!sm_cmac_ready()) break; 2183 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2184 f5_calculate_ltk(connection); 2185 break; 2186 case SM_SC_W2_CALCULATE_G2: 2187 if (!sm_cmac_ready()) break; 2188 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2189 g2_calculate(connection); 2190 break; 2191 case SM_SC_W2_CALCULATE_H6_ILK: 2192 if (!sm_cmac_ready()) break; 2193 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2194 h6_calculate_ilk(connection); 2195 break; 2196 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2197 if (!sm_cmac_ready()) break; 2198 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2199 h6_calculate_br_edr_link_key(connection); 2200 break; 2201 #endif 2202 2203 #ifdef ENABLE_LE_CENTRAL 2204 // initiator side 2205 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2206 sm_key_t peer_ltk_flipped; 2207 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2208 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2209 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2210 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2211 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2212 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2213 return; 2214 } 2215 2216 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2217 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2218 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2219 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2220 sm_timeout_reset(connection); 2221 break; 2222 #endif 2223 2224 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2225 2226 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2227 int trigger_user_response = 0; 2228 2229 uint8_t buffer[65]; 2230 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2231 // 2232 reverse_256(&ec_q[0], &buffer[1]); 2233 reverse_256(&ec_q[32], &buffer[33]); 2234 2235 #ifdef ENABLE_TESTING_SUPPORT 2236 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2237 log_info("testing_support: invalidating public key"); 2238 // flip single bit of public key coordinate 2239 buffer[1] ^= 1; 2240 } 2241 #endif 2242 2243 // stk generation method 2244 // passkey entry: notify app to show passkey or to request passkey 2245 switch (setup->sm_stk_generation_method){ 2246 case JUST_WORKS: 2247 case NUMERIC_COMPARISON: 2248 if (IS_RESPONDER(connection->sm_role)){ 2249 // responder 2250 sm_sc_start_calculating_local_confirm(connection); 2251 } else { 2252 // initiator 2253 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2254 } 2255 break; 2256 case PK_INIT_INPUT: 2257 case PK_RESP_INPUT: 2258 case PK_BOTH_INPUT: 2259 // use random TK for display 2260 memcpy(setup->sm_ra, setup->sm_tk, 16); 2261 memcpy(setup->sm_rb, setup->sm_tk, 16); 2262 setup->sm_passkey_bit = 0; 2263 2264 if (IS_RESPONDER(connection->sm_role)){ 2265 // responder 2266 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2267 } else { 2268 // initiator 2269 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2270 } 2271 trigger_user_response = 1; 2272 break; 2273 case OOB: 2274 if (IS_RESPONDER(connection->sm_role)){ 2275 // responder 2276 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2277 } else { 2278 // initiator 2279 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2280 } 2281 break; 2282 } 2283 2284 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2285 sm_timeout_reset(connection); 2286 2287 // trigger user response after sending pdu 2288 if (trigger_user_response){ 2289 sm_trigger_user_response(connection); 2290 } 2291 break; 2292 } 2293 case SM_SC_SEND_CONFIRMATION: { 2294 uint8_t buffer[17]; 2295 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2296 reverse_128(setup->sm_local_confirm, &buffer[1]); 2297 if (IS_RESPONDER(connection->sm_role)){ 2298 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2299 } else { 2300 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2301 } 2302 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2303 sm_timeout_reset(connection); 2304 break; 2305 } 2306 case SM_SC_SEND_PAIRING_RANDOM: { 2307 uint8_t buffer[17]; 2308 buffer[0] = SM_CODE_PAIRING_RANDOM; 2309 reverse_128(setup->sm_local_nonce, &buffer[1]); 2310 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2311 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2312 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2313 if (IS_RESPONDER(connection->sm_role)){ 2314 // responder 2315 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2316 } else { 2317 // initiator 2318 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2319 } 2320 } else { 2321 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2322 if (IS_RESPONDER(connection->sm_role)){ 2323 // responder 2324 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2325 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2326 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2327 } else { 2328 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2329 sm_sc_prepare_dhkey_check(connection); 2330 } 2331 } else { 2332 // initiator 2333 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2334 } 2335 } 2336 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2337 sm_timeout_reset(connection); 2338 break; 2339 } 2340 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2341 uint8_t buffer[17]; 2342 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2343 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2344 2345 if (IS_RESPONDER(connection->sm_role)){ 2346 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2347 } else { 2348 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2349 } 2350 2351 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2352 sm_timeout_reset(connection); 2353 break; 2354 } 2355 2356 #endif 2357 2358 #ifdef ENABLE_LE_PERIPHERAL 2359 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2360 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2361 2362 // start with initiator key dist flags 2363 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2364 2365 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2366 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2367 if (setup->sm_use_secure_connections){ 2368 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2369 } 2370 #endif 2371 // setup in response 2372 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); 2373 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); 2374 2375 // update key distribution after ENC was dropped 2376 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2377 2378 if (setup->sm_use_secure_connections){ 2379 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2380 } else { 2381 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2382 } 2383 2384 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2385 sm_timeout_reset(connection); 2386 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2387 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2388 sm_trigger_user_response(connection); 2389 } 2390 return; 2391 #endif 2392 2393 case SM_PH2_SEND_PAIRING_RANDOM: { 2394 uint8_t buffer[17]; 2395 buffer[0] = SM_CODE_PAIRING_RANDOM; 2396 reverse_128(setup->sm_local_random, &buffer[1]); 2397 if (IS_RESPONDER(connection->sm_role)){ 2398 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2399 } else { 2400 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2401 } 2402 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2403 sm_timeout_reset(connection); 2404 break; 2405 } 2406 2407 case SM_PH2_C1_GET_ENC_A: 2408 // already busy? 2409 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2410 // calculate confirm using aes128 engine - step 1 2411 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); 2412 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2413 sm_aes128_state = SM_AES128_ACTIVE; 2414 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2415 break; 2416 2417 case SM_PH2_C1_GET_ENC_C: 2418 // already busy? 2419 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2420 // calculate m_confirm using aes128 engine - step 1 2421 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); 2422 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2423 sm_aes128_state = SM_AES128_ACTIVE; 2424 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2425 break; 2426 2427 case SM_PH2_CALC_STK: 2428 // already busy? 2429 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2430 // calculate STK 2431 if (IS_RESPONDER(connection->sm_role)){ 2432 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2433 } else { 2434 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2435 } 2436 connection->sm_engine_state = SM_PH2_W4_STK; 2437 sm_aes128_state = SM_AES128_ACTIVE; 2438 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2439 break; 2440 2441 case SM_PH3_Y_GET_ENC: 2442 // already busy? 2443 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2444 // PH3B2 - calculate Y from - enc 2445 // Y = dm(DHK, Rand) 2446 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2447 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2448 sm_aes128_state = SM_AES128_ACTIVE; 2449 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); 2450 break; 2451 2452 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2453 uint8_t buffer[17]; 2454 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2455 reverse_128(setup->sm_local_confirm, &buffer[1]); 2456 if (IS_RESPONDER(connection->sm_role)){ 2457 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2458 } else { 2459 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2460 } 2461 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2462 sm_timeout_reset(connection); 2463 return; 2464 } 2465 #ifdef ENABLE_LE_PERIPHERAL 2466 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2467 sm_key_t stk_flipped; 2468 reverse_128(setup->sm_ltk, stk_flipped); 2469 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2470 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2471 return; 2472 } 2473 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2474 sm_key_t ltk_flipped; 2475 reverse_128(setup->sm_ltk, ltk_flipped); 2476 connection->sm_engine_state = SM_RESPONDER_IDLE; 2477 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2478 sm_done_for_handle(connection->sm_handle); 2479 return; 2480 } 2481 case SM_RESPONDER_PH4_Y_GET_ENC: 2482 // already busy? 2483 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2484 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2485 // Y = dm(DHK, Rand) 2486 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2487 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2488 sm_aes128_state = SM_AES128_ACTIVE; 2489 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); 2490 return; 2491 #endif 2492 #ifdef ENABLE_LE_CENTRAL 2493 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2494 sm_key_t stk_flipped; 2495 reverse_128(setup->sm_ltk, stk_flipped); 2496 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2497 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2498 return; 2499 } 2500 #endif 2501 2502 case SM_PH3_DISTRIBUTE_KEYS: 2503 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2504 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2505 uint8_t buffer[17]; 2506 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2507 reverse_128(setup->sm_ltk, &buffer[1]); 2508 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2509 sm_timeout_reset(connection); 2510 return; 2511 } 2512 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2513 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2514 uint8_t buffer[11]; 2515 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2516 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2517 reverse_64(setup->sm_local_rand, &buffer[3]); 2518 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2519 sm_timeout_reset(connection); 2520 return; 2521 } 2522 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2523 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2524 uint8_t buffer[17]; 2525 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2526 reverse_128(sm_persistent_irk, &buffer[1]); 2527 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2528 sm_timeout_reset(connection); 2529 return; 2530 } 2531 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2532 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2533 bd_addr_t local_address; 2534 uint8_t buffer[8]; 2535 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2536 switch (gap_random_address_get_mode()){ 2537 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2538 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2539 // public or static random 2540 gap_le_get_own_address(&buffer[1], local_address); 2541 break; 2542 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2543 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2544 // fallback to public 2545 gap_local_bd_addr(local_address); 2546 buffer[1] = 0; 2547 break; 2548 } 2549 reverse_bd_addr(local_address, &buffer[2]); 2550 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2551 sm_timeout_reset(connection); 2552 return; 2553 } 2554 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2555 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2556 2557 // hack to reproduce test runs 2558 if (test_use_fixed_local_csrk){ 2559 memset(setup->sm_local_csrk, 0xcc, 16); 2560 } 2561 2562 uint8_t buffer[17]; 2563 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2564 reverse_128(setup->sm_local_csrk, &buffer[1]); 2565 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2566 sm_timeout_reset(connection); 2567 return; 2568 } 2569 2570 // keys are sent 2571 if (IS_RESPONDER(connection->sm_role)){ 2572 // slave -> receive master keys if any 2573 if (sm_key_distribution_all_received(connection)){ 2574 sm_key_distribution_handle_all_received(connection); 2575 connection->sm_engine_state = SM_RESPONDER_IDLE; 2576 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2577 sm_done_for_handle(connection->sm_handle); 2578 } else { 2579 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2580 } 2581 } else { 2582 // master -> all done 2583 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2584 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2585 sm_done_for_handle(connection->sm_handle); 2586 } 2587 break; 2588 2589 default: 2590 break; 2591 } 2592 2593 // check again if active connection was released 2594 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2595 } 2596 } 2597 2598 // sm_aes128_state stays active 2599 static void sm_handle_encryption_result_enc_a(void *arg){ 2600 sm_connection_t * connection = (sm_connection_t*) arg; 2601 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2602 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); 2603 } 2604 2605 static void sm_handle_encryption_result_enc_b(void *arg){ 2606 sm_connection_t * connection = (sm_connection_t*) arg; 2607 sm_aes128_state = SM_AES128_IDLE; 2608 log_info_key("c1!", setup->sm_local_confirm); 2609 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2610 sm_run(); 2611 } 2612 2613 // sm_aes128_state stays active 2614 static void sm_handle_encryption_result_enc_c(void *arg){ 2615 sm_connection_t * connection = (sm_connection_t*) arg; 2616 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2617 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); 2618 } 2619 2620 static void sm_handle_encryption_result_enc_d(void * arg){ 2621 sm_connection_t * connection = (sm_connection_t*) arg; 2622 sm_aes128_state = SM_AES128_IDLE; 2623 log_info_key("c1!", sm_aes128_ciphertext); 2624 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2625 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2626 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2627 sm_run(); 2628 return; 2629 } 2630 if (IS_RESPONDER(connection->sm_role)){ 2631 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2632 sm_run(); 2633 } else { 2634 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2635 sm_aes128_state = SM_AES128_ACTIVE; 2636 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2637 } 2638 } 2639 2640 static void sm_handle_encryption_result_enc_stk(void *arg){ 2641 sm_connection_t * connection = (sm_connection_t*) arg; 2642 sm_aes128_state = SM_AES128_IDLE; 2643 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2644 log_info_key("stk", setup->sm_ltk); 2645 if (IS_RESPONDER(connection->sm_role)){ 2646 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2647 } else { 2648 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2649 } 2650 sm_run(); 2651 } 2652 2653 // sm_aes128_state stays active 2654 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2655 sm_connection_t * connection = (sm_connection_t*) arg; 2656 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2657 log_info_hex16("y", setup->sm_local_y); 2658 // PH3B3 - calculate EDIV 2659 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2660 log_info_hex16("ediv", setup->sm_local_ediv); 2661 // PH3B4 - calculate LTK - enc 2662 // LTK = d1(ER, DIV, 0)) 2663 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2664 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); 2665 } 2666 2667 #ifdef ENABLE_LE_PERIPHERAL 2668 // sm_aes128_state stays active 2669 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2670 sm_connection_t * connection = (sm_connection_t*) arg; 2671 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2672 log_info_hex16("y", setup->sm_local_y); 2673 2674 // PH3B3 - calculate DIV 2675 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2676 log_info_hex16("ediv", setup->sm_local_ediv); 2677 // PH3B4 - calculate LTK - enc 2678 // LTK = d1(ER, DIV, 0)) 2679 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2680 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); 2681 } 2682 #endif 2683 2684 // sm_aes128_state stays active 2685 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2686 sm_connection_t * connection = (sm_connection_t*) arg; 2687 log_info_key("ltk", setup->sm_ltk); 2688 // calc CSRK next 2689 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2690 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); 2691 } 2692 2693 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2694 sm_connection_t * connection = (sm_connection_t*) arg; 2695 sm_aes128_state = SM_AES128_IDLE; 2696 log_info_key("csrk", setup->sm_local_csrk); 2697 if (setup->sm_key_distribution_send_set){ 2698 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2699 } else { 2700 // no keys to send, just continue 2701 if (IS_RESPONDER(connection->sm_role)){ 2702 // slave -> receive master keys 2703 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2704 } else { 2705 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2706 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2707 } else { 2708 // master -> all done 2709 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2710 sm_done_for_handle(connection->sm_handle); 2711 } 2712 } 2713 } 2714 sm_run(); 2715 } 2716 2717 #ifdef ENABLE_LE_PERIPHERAL 2718 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2719 sm_connection_t * connection = (sm_connection_t*) arg; 2720 sm_aes128_state = SM_AES128_IDLE; 2721 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2722 log_info_key("ltk", setup->sm_ltk); 2723 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2724 sm_run(); 2725 } 2726 #endif 2727 2728 static void sm_handle_encryption_result_address_resolution(void *arg){ 2729 UNUSED(arg); 2730 sm_aes128_state = SM_AES128_IDLE; 2731 sm_address_resolution_ah_calculation_active = 0; 2732 // compare calulated address against connecting device 2733 uint8_t * hash = &sm_aes128_ciphertext[13]; 2734 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2735 log_info("LE Device Lookup: matched resolvable private address"); 2736 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2737 sm_run(); 2738 return; 2739 } 2740 // no match, try next 2741 sm_address_resolution_test++; 2742 sm_run(); 2743 } 2744 2745 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2746 UNUSED(arg); 2747 sm_aes128_state = SM_AES128_IDLE; 2748 log_info_key("irk", sm_persistent_irk); 2749 dkg_state = DKG_CALC_DHK; 2750 sm_run(); 2751 } 2752 2753 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2754 UNUSED(arg); 2755 sm_aes128_state = SM_AES128_IDLE; 2756 log_info_key("dhk", sm_persistent_dhk); 2757 dkg_state = DKG_READY; 2758 // DKG calculation complete => SM Init Finished 2759 sm_run(); 2760 } 2761 2762 static void sm_handle_encryption_result_rau(void *arg){ 2763 UNUSED(arg); 2764 sm_aes128_state = SM_AES128_IDLE; 2765 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2766 rau_state = RAU_SET_ADDRESS; 2767 sm_run(); 2768 } 2769 2770 static void sm_handle_random_result_rau(void * arg){ 2771 UNUSED(arg); 2772 // non-resolvable vs. resolvable 2773 switch (gap_random_adress_type){ 2774 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2775 // resolvable: use random as prand and calc address hash 2776 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2777 sm_random_address[0] &= 0x3f; 2778 sm_random_address[0] |= 0x40; 2779 rau_state = RAU_GET_ENC; 2780 break; 2781 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2782 default: 2783 // "The two most significant bits of the address shall be equal to ‘0’"" 2784 sm_random_address[0] &= 0x3f; 2785 rau_state = RAU_SET_ADDRESS; 2786 break; 2787 } 2788 sm_run(); 2789 } 2790 2791 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2792 static void sm_handle_random_result_sc_get_random(void * arg){ 2793 sm_connection_t * connection = (sm_connection_t*) arg; 2794 2795 // OOB 2796 if (setup->sm_stk_generation_method == OOB){ 2797 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2798 sm_run(); 2799 return; 2800 } 2801 2802 // initiator & jw/nc -> send pairing random 2803 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2804 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2805 } else { 2806 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2807 } 2808 sm_run(); 2809 } 2810 #endif 2811 2812 static void sm_handle_random_result_ph2_random(void * arg){ 2813 sm_connection_t * connection = (sm_connection_t*) arg; 2814 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2815 sm_run(); 2816 } 2817 2818 static void sm_handle_random_result_ph2_tk(void * arg){ 2819 sm_connection_t * connection = (sm_connection_t*) arg; 2820 sm_reset_tk(); 2821 uint32_t tk; 2822 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2823 // map random to 0-999999 without speding much cycles on a modulus operation 2824 tk = little_endian_read_32(sm_random_data,0); 2825 tk = tk & 0xfffff; // 1048575 2826 if (tk >= 999999){ 2827 tk = tk - 999999; 2828 } 2829 } else { 2830 // override with pre-defined passkey 2831 tk = sm_fixed_passkey_in_display_role; 2832 } 2833 big_endian_store_32(setup->sm_tk, 12, tk); 2834 if (IS_RESPONDER(connection->sm_role)){ 2835 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2836 } else { 2837 if (setup->sm_use_secure_connections){ 2838 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2839 } else { 2840 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2841 sm_trigger_user_response(connection); 2842 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2843 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2844 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2845 } 2846 } 2847 } 2848 sm_run(); 2849 } 2850 2851 static void sm_handle_random_result_ph3_div(void * arg){ 2852 sm_connection_t * connection = (sm_connection_t*) arg; 2853 // use 16 bit from random value as div 2854 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2855 log_info_hex16("div", setup->sm_local_div); 2856 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2857 sm_run(); 2858 } 2859 2860 static void sm_handle_random_result_ph3_random(void * arg){ 2861 sm_connection_t * connection = (sm_connection_t*) arg; 2862 reverse_64(sm_random_data, setup->sm_local_rand); 2863 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2864 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2865 // no db for authenticated flag hack: store flag in bit 4 of LSB 2866 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2867 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2868 } 2869 2870 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2871 2872 UNUSED(channel); // ok: there is no channel 2873 UNUSED(size); // ok: fixed format HCI events 2874 2875 sm_connection_t * sm_conn; 2876 hci_con_handle_t con_handle; 2877 2878 switch (packet_type) { 2879 2880 case HCI_EVENT_PACKET: 2881 switch (hci_event_packet_get_type(packet)) { 2882 2883 case BTSTACK_EVENT_STATE: 2884 // bt stack activated, get started 2885 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2886 log_info("HCI Working!"); 2887 2888 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2889 2890 // trigger Random Address generation if requested before 2891 switch (gap_random_adress_type){ 2892 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2893 rau_state = RAU_IDLE; 2894 break; 2895 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2896 rau_state = RAU_SET_ADDRESS; 2897 break; 2898 default: 2899 rau_state = RAU_W4_RANDOM; 2900 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 8, &sm_handle_random_result_rau, NULL); 2901 break; 2902 } 2903 sm_run(); 2904 } 2905 break; 2906 2907 case HCI_EVENT_LE_META: 2908 switch (packet[2]) { 2909 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2910 2911 log_info("sm: connected"); 2912 2913 if (packet[3]) return; // connection failed 2914 2915 con_handle = little_endian_read_16(packet, 4); 2916 sm_conn = sm_get_connection_for_handle(con_handle); 2917 if (!sm_conn) break; 2918 2919 sm_conn->sm_handle = con_handle; 2920 sm_conn->sm_role = packet[6]; 2921 sm_conn->sm_peer_addr_type = packet[7]; 2922 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 2923 2924 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2925 2926 // reset security properties 2927 sm_conn->sm_connection_encrypted = 0; 2928 sm_conn->sm_connection_authenticated = 0; 2929 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2930 sm_conn->sm_le_db_index = -1; 2931 2932 // prepare CSRK lookup (does not involve setup) 2933 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2934 2935 // just connected -> everything else happens in sm_run() 2936 if (IS_RESPONDER(sm_conn->sm_role)){ 2937 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2938 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2939 if (sm_slave_request_security) { 2940 // request security if requested by app 2941 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2942 } else { 2943 // otherwise, wait for pairing request 2944 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2945 } 2946 } 2947 break; 2948 } else { 2949 // master 2950 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2951 } 2952 break; 2953 2954 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2955 con_handle = little_endian_read_16(packet, 3); 2956 sm_conn = sm_get_connection_for_handle(con_handle); 2957 if (!sm_conn) break; 2958 2959 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2960 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2961 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2962 break; 2963 } 2964 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2965 // PH2 SEND LTK as we need to exchange keys in PH3 2966 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2967 break; 2968 } 2969 2970 // store rand and ediv 2971 reverse_64(&packet[5], sm_conn->sm_local_rand); 2972 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2973 2974 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2975 // potentially stored LTK is from the master 2976 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2977 if (sm_reconstruct_ltk_without_le_device_db_entry){ 2978 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2979 break; 2980 } 2981 // additionally check if remote is in LE Device DB if requested 2982 switch(sm_conn->sm_irk_lookup_state){ 2983 case IRK_LOOKUP_FAILED: 2984 log_info("LTK Request: device not in device db"); 2985 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2986 break; 2987 case IRK_LOOKUP_SUCCEEDED: 2988 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2989 break; 2990 default: 2991 // wait for irk look doen 2992 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 2993 break; 2994 } 2995 break; 2996 } 2997 2998 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2999 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3000 #else 3001 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3002 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3003 #endif 3004 break; 3005 3006 default: 3007 break; 3008 } 3009 break; 3010 3011 case HCI_EVENT_ENCRYPTION_CHANGE: 3012 con_handle = little_endian_read_16(packet, 3); 3013 sm_conn = sm_get_connection_for_handle(con_handle); 3014 if (!sm_conn) break; 3015 3016 sm_conn->sm_connection_encrypted = packet[5]; 3017 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3018 sm_conn->sm_actual_encryption_key_size); 3019 log_info("event handler, state %u", sm_conn->sm_engine_state); 3020 3021 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3022 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3023 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3024 sm_done_for_handle(sm_conn->sm_handle); 3025 break; 3026 } 3027 3028 if (!sm_conn->sm_connection_encrypted) break; 3029 3030 // continue pairing 3031 switch (sm_conn->sm_engine_state){ 3032 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3033 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3034 sm_done_for_handle(sm_conn->sm_handle); 3035 break; 3036 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3037 if (IS_RESPONDER(sm_conn->sm_role)){ 3038 // slave 3039 if (setup->sm_use_secure_connections){ 3040 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3041 } else { 3042 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3043 } 3044 } else { 3045 // master 3046 if (sm_key_distribution_all_received(sm_conn)){ 3047 // skip receiving keys as there are none 3048 sm_key_distribution_handle_all_received(sm_conn); 3049 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3050 } else { 3051 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3052 } 3053 } 3054 break; 3055 default: 3056 break; 3057 } 3058 break; 3059 3060 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3061 con_handle = little_endian_read_16(packet, 3); 3062 sm_conn = sm_get_connection_for_handle(con_handle); 3063 if (!sm_conn) break; 3064 3065 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3066 log_info("event handler, state %u", sm_conn->sm_engine_state); 3067 // continue if part of initial pairing 3068 switch (sm_conn->sm_engine_state){ 3069 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3070 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3071 sm_done_for_handle(sm_conn->sm_handle); 3072 break; 3073 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3074 if (IS_RESPONDER(sm_conn->sm_role)){ 3075 // slave 3076 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3077 } else { 3078 // master 3079 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3080 } 3081 break; 3082 default: 3083 break; 3084 } 3085 break; 3086 3087 3088 case HCI_EVENT_DISCONNECTION_COMPLETE: 3089 con_handle = little_endian_read_16(packet, 3); 3090 sm_done_for_handle(con_handle); 3091 sm_conn = sm_get_connection_for_handle(con_handle); 3092 if (!sm_conn) break; 3093 3094 // delete stored bonding on disconnect with authentication failure in ph0 3095 if (sm_conn->sm_role == 0 3096 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3097 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3098 le_device_db_remove(sm_conn->sm_le_db_index); 3099 } 3100 3101 // pairing failed, if it was ongoing 3102 if (sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED && sm_conn->sm_engine_state != SM_GENERAL_IDLE){ 3103 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3104 } 3105 3106 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3107 sm_conn->sm_handle = 0; 3108 break; 3109 3110 case HCI_EVENT_COMMAND_COMPLETE: 3111 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3112 // set local addr for le device db 3113 bd_addr_t addr; 3114 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3115 le_device_db_set_local_bd_addr(addr); 3116 } 3117 break; 3118 default: 3119 break; 3120 } 3121 break; 3122 default: 3123 break; 3124 } 3125 3126 sm_run(); 3127 } 3128 3129 static inline int sm_calc_actual_encryption_key_size(int other){ 3130 if (other < sm_min_encryption_key_size) return 0; 3131 if (other < sm_max_encryption_key_size) return other; 3132 return sm_max_encryption_key_size; 3133 } 3134 3135 3136 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3137 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3138 switch (method){ 3139 case JUST_WORKS: 3140 case NUMERIC_COMPARISON: 3141 return 1; 3142 default: 3143 return 0; 3144 } 3145 } 3146 // responder 3147 3148 static int sm_passkey_used(stk_generation_method_t method){ 3149 switch (method){ 3150 case PK_RESP_INPUT: 3151 return 1; 3152 default: 3153 return 0; 3154 } 3155 } 3156 3157 static int sm_passkey_entry(stk_generation_method_t method){ 3158 switch (method){ 3159 case PK_RESP_INPUT: 3160 case PK_INIT_INPUT: 3161 case PK_BOTH_INPUT: 3162 return 1; 3163 default: 3164 return 0; 3165 } 3166 } 3167 3168 #endif 3169 3170 /** 3171 * @return ok 3172 */ 3173 static int sm_validate_stk_generation_method(void){ 3174 // check if STK generation method is acceptable by client 3175 switch (setup->sm_stk_generation_method){ 3176 case JUST_WORKS: 3177 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3178 case PK_RESP_INPUT: 3179 case PK_INIT_INPUT: 3180 case PK_BOTH_INPUT: 3181 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3182 case OOB: 3183 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3184 case NUMERIC_COMPARISON: 3185 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3186 default: 3187 return 0; 3188 } 3189 } 3190 3191 // size of complete sm_pdu used to validate input 3192 static const uint8_t sm_pdu_size[] = { 3193 0, // 0x00 invalid opcode 3194 7, // 0x01 pairing request 3195 7, // 0x02 pairing response 3196 17, // 0x03 pairing confirm 3197 17, // 0x04 pairing random 3198 2, // 0x05 pairing failed 3199 17, // 0x06 encryption information 3200 11, // 0x07 master identification 3201 17, // 0x08 identification information 3202 8, // 0x09 identify address information 3203 17, // 0x0a signing information 3204 2, // 0x0b security request 3205 65, // 0x0c pairing public key 3206 17, // 0x0d pairing dhk check 3207 2, // 0x0e keypress notification 3208 }; 3209 3210 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3211 3212 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3213 sm_run(); 3214 } 3215 3216 if (packet_type != SM_DATA_PACKET) return; 3217 if (size == 0) return; 3218 3219 uint8_t sm_pdu_code = packet[0]; 3220 3221 // validate pdu size 3222 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3223 if (sm_pdu_size[sm_pdu_code] != size) return; 3224 3225 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3226 if (!sm_conn) return; 3227 3228 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3229 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3230 sm_done_for_handle(con_handle); 3231 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3232 return; 3233 } 3234 3235 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3236 3237 int err; 3238 UNUSED(err); 3239 3240 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3241 uint8_t buffer[5]; 3242 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3243 buffer[1] = 3; 3244 little_endian_store_16(buffer, 2, con_handle); 3245 buffer[4] = packet[1]; 3246 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3247 return; 3248 } 3249 3250 switch (sm_conn->sm_engine_state){ 3251 3252 // a sm timeout requries a new physical connection 3253 case SM_GENERAL_TIMEOUT: 3254 return; 3255 3256 #ifdef ENABLE_LE_CENTRAL 3257 3258 // Initiator 3259 case SM_INITIATOR_CONNECTED: 3260 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3261 sm_pdu_received_in_wrong_state(sm_conn); 3262 break; 3263 } 3264 3265 // IRK complete? 3266 switch (sm_conn->sm_irk_lookup_state){ 3267 case IRK_LOOKUP_FAILED: 3268 case IRK_LOOKUP_SUCCEEDED: 3269 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3270 break; 3271 default: 3272 break; 3273 } 3274 3275 // otherwise, store security request 3276 sm_conn->sm_security_request_received = 1; 3277 break; 3278 3279 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3280 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3281 sm_pdu_received_in_wrong_state(sm_conn); 3282 break; 3283 } 3284 3285 // store pairing request 3286 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3287 err = sm_stk_generation_init(sm_conn); 3288 3289 #ifdef ENABLE_TESTING_SUPPORT 3290 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3291 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3292 err = test_pairing_failure; 3293 } 3294 #endif 3295 3296 if (err){ 3297 setup->sm_pairing_failed_reason = err; 3298 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3299 break; 3300 } 3301 3302 // generate random number first, if we need to show passkey 3303 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3304 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3305 break; 3306 } 3307 3308 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3309 if (setup->sm_use_secure_connections){ 3310 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3311 if (setup->sm_stk_generation_method == JUST_WORKS){ 3312 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3313 sm_trigger_user_response(sm_conn); 3314 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3315 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3316 } 3317 } else { 3318 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3319 } 3320 break; 3321 } 3322 #endif 3323 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3324 sm_trigger_user_response(sm_conn); 3325 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3326 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3327 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3328 } 3329 break; 3330 3331 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3332 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3333 sm_pdu_received_in_wrong_state(sm_conn); 3334 break; 3335 } 3336 3337 // store s_confirm 3338 reverse_128(&packet[1], setup->sm_peer_confirm); 3339 3340 #ifdef ENABLE_TESTING_SUPPORT 3341 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3342 log_info("testing_support: reset confirm value"); 3343 memset(setup->sm_peer_confirm, 0, 16); 3344 } 3345 #endif 3346 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3347 break; 3348 3349 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3350 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3351 sm_pdu_received_in_wrong_state(sm_conn); 3352 break;; 3353 } 3354 3355 // received random value 3356 reverse_128(&packet[1], setup->sm_peer_random); 3357 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3358 break; 3359 #endif 3360 3361 #ifdef ENABLE_LE_PERIPHERAL 3362 // Responder 3363 case SM_RESPONDER_IDLE: 3364 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3365 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3366 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3367 sm_pdu_received_in_wrong_state(sm_conn); 3368 break;; 3369 } 3370 3371 // store pairing request 3372 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3373 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3374 break; 3375 #endif 3376 3377 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3378 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3379 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3380 sm_pdu_received_in_wrong_state(sm_conn); 3381 break; 3382 } 3383 3384 // store public key for DH Key calculation 3385 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3386 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3387 3388 // validate public key 3389 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3390 if (err){ 3391 log_error("sm: peer public key invalid %x", err); 3392 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3393 break; 3394 } 3395 3396 // start calculating dhkey 3397 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3398 3399 3400 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3401 if (IS_RESPONDER(sm_conn->sm_role)){ 3402 // responder 3403 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3404 } else { 3405 // initiator 3406 // stk generation method 3407 // passkey entry: notify app to show passkey or to request passkey 3408 switch (setup->sm_stk_generation_method){ 3409 case JUST_WORKS: 3410 case NUMERIC_COMPARISON: 3411 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3412 break; 3413 case PK_RESP_INPUT: 3414 sm_sc_start_calculating_local_confirm(sm_conn); 3415 break; 3416 case PK_INIT_INPUT: 3417 case PK_BOTH_INPUT: 3418 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3419 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3420 break; 3421 } 3422 sm_sc_start_calculating_local_confirm(sm_conn); 3423 break; 3424 case OOB: 3425 // generate Nx 3426 log_info("Generate Na"); 3427 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3428 break; 3429 } 3430 } 3431 break; 3432 3433 case SM_SC_W4_CONFIRMATION: 3434 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3435 sm_pdu_received_in_wrong_state(sm_conn); 3436 break; 3437 } 3438 // received confirm value 3439 reverse_128(&packet[1], setup->sm_peer_confirm); 3440 3441 #ifdef ENABLE_TESTING_SUPPORT 3442 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3443 log_info("testing_support: reset confirm value"); 3444 memset(setup->sm_peer_confirm, 0, 16); 3445 } 3446 #endif 3447 if (IS_RESPONDER(sm_conn->sm_role)){ 3448 // responder 3449 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3450 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3451 // still waiting for passkey 3452 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3453 break; 3454 } 3455 } 3456 sm_sc_start_calculating_local_confirm(sm_conn); 3457 } else { 3458 // initiator 3459 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3460 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3461 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3462 } else { 3463 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3464 } 3465 } 3466 break; 3467 3468 case SM_SC_W4_PAIRING_RANDOM: 3469 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3470 sm_pdu_received_in_wrong_state(sm_conn); 3471 break; 3472 } 3473 3474 // received random value 3475 reverse_128(&packet[1], setup->sm_peer_nonce); 3476 3477 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3478 // only check for JUST WORK/NC in initiator role OR passkey entry 3479 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3480 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3481 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3482 break; 3483 } 3484 3485 // OOB 3486 if (setup->sm_stk_generation_method == OOB){ 3487 3488 // setup local random, set to zero if remote did not receive our data 3489 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3490 if (IS_RESPONDER(sm_conn->sm_role)){ 3491 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3492 log_info("Reset rb as A does not have OOB data"); 3493 memset(setup->sm_rb, 0, 16); 3494 } else { 3495 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3496 log_info("Use stored rb"); 3497 log_info_hexdump(setup->sm_rb, 16); 3498 } 3499 } else { 3500 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3501 log_info("Reset ra as B does not have OOB data"); 3502 memset(setup->sm_ra, 0, 16); 3503 } else { 3504 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3505 log_info("Use stored ra"); 3506 log_info_hexdump(setup->sm_ra, 16); 3507 } 3508 } 3509 3510 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3511 if (setup->sm_have_oob_data){ 3512 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3513 break; 3514 } 3515 } 3516 3517 // TODO: we only get here for Responder role with JW/NC 3518 sm_sc_state_after_receiving_random(sm_conn); 3519 break; 3520 3521 case SM_SC_W2_CALCULATE_G2: 3522 case SM_SC_W4_CALCULATE_G2: 3523 case SM_SC_W4_CALCULATE_DHKEY: 3524 case SM_SC_W2_CALCULATE_F5_SALT: 3525 case SM_SC_W4_CALCULATE_F5_SALT: 3526 case SM_SC_W2_CALCULATE_F5_MACKEY: 3527 case SM_SC_W4_CALCULATE_F5_MACKEY: 3528 case SM_SC_W2_CALCULATE_F5_LTK: 3529 case SM_SC_W4_CALCULATE_F5_LTK: 3530 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3531 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3532 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3533 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3534 sm_pdu_received_in_wrong_state(sm_conn); 3535 break; 3536 } 3537 // store DHKey Check 3538 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3539 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3540 3541 // have we been only waiting for dhkey check command? 3542 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3543 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3544 } 3545 break; 3546 #endif 3547 3548 #ifdef ENABLE_LE_PERIPHERAL 3549 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3550 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3551 sm_pdu_received_in_wrong_state(sm_conn); 3552 break; 3553 } 3554 3555 // received confirm value 3556 reverse_128(&packet[1], setup->sm_peer_confirm); 3557 3558 #ifdef ENABLE_TESTING_SUPPORT 3559 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3560 log_info("testing_support: reset confirm value"); 3561 memset(setup->sm_peer_confirm, 0, 16); 3562 } 3563 #endif 3564 // notify client to hide shown passkey 3565 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3566 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3567 } 3568 3569 // handle user cancel pairing? 3570 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3571 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3572 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3573 break; 3574 } 3575 3576 // wait for user action? 3577 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3578 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3579 break; 3580 } 3581 3582 // calculate and send local_confirm 3583 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3584 break; 3585 3586 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3587 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3588 sm_pdu_received_in_wrong_state(sm_conn); 3589 break;; 3590 } 3591 3592 // received random value 3593 reverse_128(&packet[1], setup->sm_peer_random); 3594 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3595 break; 3596 #endif 3597 3598 case SM_PH3_RECEIVE_KEYS: 3599 switch(sm_pdu_code){ 3600 case SM_CODE_ENCRYPTION_INFORMATION: 3601 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3602 reverse_128(&packet[1], setup->sm_peer_ltk); 3603 break; 3604 3605 case SM_CODE_MASTER_IDENTIFICATION: 3606 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3607 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3608 reverse_64(&packet[3], setup->sm_peer_rand); 3609 break; 3610 3611 case SM_CODE_IDENTITY_INFORMATION: 3612 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3613 reverse_128(&packet[1], setup->sm_peer_irk); 3614 break; 3615 3616 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3617 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3618 setup->sm_peer_addr_type = packet[1]; 3619 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3620 break; 3621 3622 case SM_CODE_SIGNING_INFORMATION: 3623 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3624 reverse_128(&packet[1], setup->sm_peer_csrk); 3625 break; 3626 default: 3627 // Unexpected PDU 3628 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3629 break; 3630 } 3631 // done with key distribution? 3632 if (sm_key_distribution_all_received(sm_conn)){ 3633 3634 sm_key_distribution_handle_all_received(sm_conn); 3635 3636 if (IS_RESPONDER(sm_conn->sm_role)){ 3637 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3638 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3639 } else { 3640 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3641 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3642 sm_done_for_handle(sm_conn->sm_handle); 3643 } 3644 } else { 3645 if (setup->sm_use_secure_connections){ 3646 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3647 } else { 3648 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3649 } 3650 } 3651 } 3652 break; 3653 default: 3654 // Unexpected PDU 3655 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3656 break; 3657 } 3658 3659 // try to send preparared packet 3660 sm_run(); 3661 } 3662 3663 // Security Manager Client API 3664 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3665 sm_get_oob_data = get_oob_data_callback; 3666 } 3667 3668 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)){ 3669 sm_get_sc_oob_data = get_sc_oob_data_callback; 3670 } 3671 3672 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3673 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3674 } 3675 3676 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3677 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3678 } 3679 3680 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3681 sm_min_encryption_key_size = min_size; 3682 sm_max_encryption_key_size = max_size; 3683 } 3684 3685 void sm_set_authentication_requirements(uint8_t auth_req){ 3686 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3687 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3688 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3689 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3690 } 3691 #endif 3692 sm_auth_req = auth_req; 3693 } 3694 3695 void sm_set_io_capabilities(io_capability_t io_capability){ 3696 sm_io_capabilities = io_capability; 3697 } 3698 3699 #ifdef ENABLE_LE_PERIPHERAL 3700 void sm_set_request_security(int enable){ 3701 sm_slave_request_security = enable; 3702 } 3703 #endif 3704 3705 void sm_set_er(sm_key_t er){ 3706 memcpy(sm_persistent_er, er, 16); 3707 } 3708 3709 void sm_set_ir(sm_key_t ir){ 3710 memcpy(sm_persistent_ir, ir, 16); 3711 } 3712 3713 // Testing support only 3714 void sm_test_set_irk(sm_key_t irk){ 3715 memcpy(sm_persistent_irk, irk, 16); 3716 sm_persistent_irk_ready = 1; 3717 } 3718 3719 void sm_test_use_fixed_local_csrk(void){ 3720 test_use_fixed_local_csrk = 1; 3721 } 3722 3723 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3724 static void sm_ec_generated(void * arg){ 3725 UNUSED(arg); 3726 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3727 // trigger pairing if pending for ec key 3728 sm_run(); 3729 } 3730 static void sm_ec_generate_new_key(void){ 3731 log_info("sm: generate new ec key"); 3732 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3733 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3734 } 3735 #endif 3736 3737 #ifdef ENABLE_TESTING_SUPPORT 3738 void sm_test_set_pairing_failure(int reason){ 3739 test_pairing_failure = reason; 3740 } 3741 #endif 3742 3743 void sm_init(void){ 3744 // set some (BTstack default) ER and IR 3745 int i; 3746 sm_key_t er; 3747 sm_key_t ir; 3748 for (i=0;i<16;i++){ 3749 er[i] = 0x30 + i; 3750 ir[i] = 0x90 + i; 3751 } 3752 sm_set_er(er); 3753 sm_set_ir(ir); 3754 // defaults 3755 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3756 | SM_STK_GENERATION_METHOD_OOB 3757 | SM_STK_GENERATION_METHOD_PASSKEY 3758 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3759 3760 sm_max_encryption_key_size = 16; 3761 sm_min_encryption_key_size = 7; 3762 3763 sm_fixed_passkey_in_display_role = 0xffffffff; 3764 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3765 3766 #ifdef USE_CMAC_ENGINE 3767 sm_cmac_active = 0; 3768 #endif 3769 dkg_state = DKG_W4_WORKING; 3770 rau_state = RAU_W4_WORKING; 3771 sm_aes128_state = SM_AES128_IDLE; 3772 sm_address_resolution_test = -1; // no private address to resolve yet 3773 sm_address_resolution_ah_calculation_active = 0; 3774 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3775 sm_address_resolution_general_queue = NULL; 3776 3777 gap_random_adress_update_period = 15 * 60 * 1000L; 3778 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3779 3780 test_use_fixed_local_csrk = 0; 3781 3782 // register for HCI Events from HCI 3783 hci_event_callback_registration.callback = &sm_event_packet_handler; 3784 hci_add_event_handler(&hci_event_callback_registration); 3785 3786 // 3787 btstack_crypto_init(); 3788 3789 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3790 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3791 3792 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3793 sm_ec_generate_new_key(); 3794 #endif 3795 } 3796 3797 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3798 sm_fixed_passkey_in_display_role = passkey; 3799 } 3800 3801 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3802 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3803 } 3804 3805 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3806 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3807 if (!hci_con) return NULL; 3808 return &hci_con->sm_connection; 3809 } 3810 3811 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3812 switch (sm_conn->sm_engine_state){ 3813 case SM_GENERAL_IDLE: 3814 case SM_RESPONDER_IDLE: 3815 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3816 sm_run(); 3817 break; 3818 default: 3819 break; 3820 } 3821 } 3822 3823 /** 3824 * @brief Trigger Security Request 3825 */ 3826 void sm_send_security_request(hci_con_handle_t con_handle){ 3827 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3828 if (!sm_conn) return; 3829 sm_send_security_request_for_connection(sm_conn); 3830 } 3831 3832 // request pairing 3833 void sm_request_pairing(hci_con_handle_t con_handle){ 3834 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3835 if (!sm_conn) return; // wrong connection 3836 3837 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3838 if (IS_RESPONDER(sm_conn->sm_role)){ 3839 sm_send_security_request_for_connection(sm_conn); 3840 } else { 3841 // used as a trigger to start central/master/initiator security procedures 3842 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3843 switch (sm_conn->sm_irk_lookup_state){ 3844 case IRK_LOOKUP_SUCCEEDED: 3845 case IRK_LOOKUP_FAILED: 3846 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3847 break; 3848 default: 3849 log_info("irk lookup pending"); 3850 sm_conn->sm_pairing_requested = 1; 3851 break; 3852 } 3853 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3854 sm_conn->sm_pairing_requested = 1; 3855 } 3856 } 3857 sm_run(); 3858 } 3859 3860 // called by client app on authorization request 3861 void sm_authorization_decline(hci_con_handle_t con_handle){ 3862 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3863 if (!sm_conn) return; // wrong connection 3864 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3865 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3866 } 3867 3868 void sm_authorization_grant(hci_con_handle_t con_handle){ 3869 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3870 if (!sm_conn) return; // wrong connection 3871 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3872 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3873 } 3874 3875 // GAP Bonding API 3876 3877 void sm_bonding_decline(hci_con_handle_t con_handle){ 3878 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3879 if (!sm_conn) return; // wrong connection 3880 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3881 log_info("decline, state %u", sm_conn->sm_engine_state); 3882 switch(sm_conn->sm_engine_state){ 3883 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3884 case SM_SC_W4_USER_RESPONSE: 3885 case SM_SC_W4_CONFIRMATION: 3886 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3887 #endif 3888 case SM_PH1_W4_USER_RESPONSE: 3889 switch (setup->sm_stk_generation_method){ 3890 case PK_RESP_INPUT: 3891 case PK_INIT_INPUT: 3892 case PK_BOTH_INPUT: 3893 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 3894 break; 3895 case NUMERIC_COMPARISON: 3896 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3897 break; 3898 case JUST_WORKS: 3899 case OOB: 3900 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3901 break; 3902 } 3903 break; 3904 default: 3905 break; 3906 } 3907 sm_run(); 3908 } 3909 3910 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3911 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3912 if (!sm_conn) return; // wrong connection 3913 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3914 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3915 if (setup->sm_use_secure_connections){ 3916 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3917 } else { 3918 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3919 } 3920 } 3921 3922 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3923 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3924 sm_sc_prepare_dhkey_check(sm_conn); 3925 } 3926 #endif 3927 3928 sm_run(); 3929 } 3930 3931 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3932 // for now, it's the same 3933 sm_just_works_confirm(con_handle); 3934 } 3935 3936 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3937 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3938 if (!sm_conn) return; // wrong connection 3939 sm_reset_tk(); 3940 big_endian_store_32(setup->sm_tk, 12, passkey); 3941 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3942 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3943 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3944 } 3945 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3946 memcpy(setup->sm_ra, setup->sm_tk, 16); 3947 memcpy(setup->sm_rb, setup->sm_tk, 16); 3948 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3949 sm_sc_start_calculating_local_confirm(sm_conn); 3950 } 3951 #endif 3952 sm_run(); 3953 } 3954 3955 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3956 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3957 if (!sm_conn) return; // wrong connection 3958 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3959 uint8_t num_actions = setup->sm_keypress_notification >> 5; 3960 uint8_t flags = setup->sm_keypress_notification & 0x1f; 3961 switch (action){ 3962 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 3963 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 3964 flags |= (1 << action); 3965 break; 3966 case SM_KEYPRESS_PASSKEY_CLEARED: 3967 // clear counter, keypress & erased flags + set passkey cleared 3968 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 3969 break; 3970 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 3971 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 3972 // erase actions queued 3973 num_actions--; 3974 if (num_actions == 0){ 3975 // clear counter, keypress & erased flags 3976 flags &= 0x19; 3977 } 3978 break; 3979 } 3980 num_actions++; 3981 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 3982 break; 3983 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 3984 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 3985 // enter actions queued 3986 num_actions--; 3987 if (num_actions == 0){ 3988 // clear counter, keypress & erased flags 3989 flags &= 0x19; 3990 } 3991 break; 3992 } 3993 num_actions++; 3994 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 3995 break; 3996 default: 3997 break; 3998 } 3999 setup->sm_keypress_notification = (num_actions << 5) | flags; 4000 sm_run(); 4001 } 4002 4003 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4004 static void sm_handle_random_result_oob(void * arg){ 4005 UNUSED(arg); 4006 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4007 sm_run(); 4008 } 4009 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4010 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4011 sm_sc_oob_callback = callback; 4012 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4013 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4014 return 0; 4015 } 4016 #endif 4017 4018 /** 4019 * @brief Identify device in LE Device DB 4020 * @param handle 4021 * @returns index from le_device_db or -1 if not found/identified 4022 */ 4023 int sm_le_device_index(hci_con_handle_t con_handle ){ 4024 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4025 if (!sm_conn) return -1; 4026 return sm_conn->sm_le_db_index; 4027 } 4028 4029 static int gap_random_address_type_requires_updates(void){ 4030 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4031 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4032 return 1; 4033 } 4034 4035 static uint8_t own_address_type(void){ 4036 switch (gap_random_adress_type){ 4037 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4038 return BD_ADDR_TYPE_LE_PUBLIC; 4039 default: 4040 return BD_ADDR_TYPE_LE_RANDOM; 4041 } 4042 } 4043 4044 // GAP LE API 4045 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4046 gap_random_address_update_stop(); 4047 gap_random_adress_type = random_address_type; 4048 hci_le_set_own_address_type(own_address_type()); 4049 if (!gap_random_address_type_requires_updates()) return; 4050 gap_random_address_update_start(); 4051 gap_random_address_trigger(); 4052 } 4053 4054 gap_random_address_type_t gap_random_address_get_mode(void){ 4055 return gap_random_adress_type; 4056 } 4057 4058 void gap_random_address_set_update_period(int period_ms){ 4059 gap_random_adress_update_period = period_ms; 4060 if (!gap_random_address_type_requires_updates()) return; 4061 gap_random_address_update_stop(); 4062 gap_random_address_update_start(); 4063 } 4064 4065 void gap_random_address_set(bd_addr_t addr){ 4066 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4067 memcpy(sm_random_address, addr, 6); 4068 if (rau_state == RAU_W4_WORKING) return; 4069 rau_state = RAU_SET_ADDRESS; 4070 sm_run(); 4071 } 4072 4073 #ifdef ENABLE_LE_PERIPHERAL 4074 /* 4075 * @brief Set Advertisement Paramters 4076 * @param adv_int_min 4077 * @param adv_int_max 4078 * @param adv_type 4079 * @param direct_address_type 4080 * @param direct_address 4081 * @param channel_map 4082 * @param filter_policy 4083 * 4084 * @note own_address_type is used from gap_random_address_set_mode 4085 */ 4086 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4087 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4088 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4089 direct_address_typ, direct_address, channel_map, filter_policy); 4090 } 4091 #endif 4092 4093 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4094 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4095 // wrong connection 4096 if (!sm_conn) return 0; 4097 // already encrypted 4098 if (sm_conn->sm_connection_encrypted) return 0; 4099 // only central can re-encrypt 4100 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4101 // irk status? 4102 switch(sm_conn->sm_irk_lookup_state){ 4103 case IRK_LOOKUP_FAILED: 4104 // done, cannot setup encryption 4105 return 0; 4106 case IRK_LOOKUP_SUCCEEDED: 4107 break; 4108 default: 4109 // IR Lookup pending 4110 return 1; 4111 } 4112 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4113 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4114 } 4115