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_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #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" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 PK_BOTH_INPUT, // Only input on both, both input PK 128 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on one (SC) or both sides (legacy) 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_DONE, 160 } ec_key_generation_state_t; 161 162 typedef enum { 163 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 164 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 165 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 166 } sm_state_var_t; 167 168 typedef enum { 169 SM_SC_OOB_IDLE, 170 SM_SC_OOB_W4_RANDOM, 171 SM_SC_OOB_W2_CALC_CONFIRM, 172 SM_SC_OOB_W4_CONFIRM, 173 } sm_sc_oob_state_t; 174 175 typedef uint8_t sm_key24_t[3]; 176 typedef uint8_t sm_key56_t[7]; 177 typedef uint8_t sm_key256_t[32]; 178 179 // 180 // GLOBAL DATA 181 // 182 183 static bool test_use_fixed_local_csrk; 184 static bool test_use_fixed_local_irk; 185 186 #ifdef ENABLE_TESTING_SUPPORT 187 static uint8_t test_pairing_failure; 188 #endif 189 190 // configuration 191 static uint8_t sm_accepted_stk_generation_methods; 192 static uint8_t sm_max_encryption_key_size; 193 static uint8_t sm_min_encryption_key_size; 194 static uint8_t sm_auth_req = 0; 195 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 196 static uint8_t sm_slave_request_security; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 201 static bool sm_sc_only_mode; 202 static uint8_t sm_sc_oob_random[16]; 203 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 204 static sm_sc_oob_state_t sm_sc_oob_state; 205 #endif 206 207 208 static uint8_t sm_persistent_keys_random_active; 209 static const btstack_tlv_t * sm_tlv_impl; 210 static void * sm_tlv_context; 211 212 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 213 static sm_key_t sm_persistent_er; 214 static sm_key_t sm_persistent_ir; 215 216 // derived from sm_persistent_ir 217 static sm_key_t sm_persistent_dhk; 218 static sm_key_t sm_persistent_irk; 219 static derived_key_generation_t dkg_state; 220 221 // derived from sm_persistent_er 222 // .. 223 224 // random address update 225 static random_address_update_t rau_state; 226 static bd_addr_t sm_random_address; 227 228 #ifdef USE_CMAC_ENGINE 229 // CMAC Calculation: General 230 static btstack_crypto_aes128_cmac_t sm_cmac_request; 231 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 232 static uint8_t sm_cmac_active; 233 static uint8_t sm_cmac_hash[16]; 234 #endif 235 236 // CMAC for ATT Signed Writes 237 #ifdef ENABLE_LE_SIGNED_WRITE 238 static uint16_t sm_cmac_signed_write_message_len; 239 static uint8_t sm_cmac_signed_write_header[3]; 240 static const uint8_t * sm_cmac_signed_write_message; 241 static uint8_t sm_cmac_signed_write_sign_counter[4]; 242 #endif 243 244 // CMAC for Secure Connection functions 245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 246 static sm_connection_t * sm_cmac_connection; 247 static uint8_t sm_cmac_sc_buffer[80]; 248 #endif 249 250 // resolvable private address lookup / CSRK calculation 251 static int sm_address_resolution_test; 252 static int sm_address_resolution_ah_calculation_active; 253 static uint8_t sm_address_resolution_addr_type; 254 static bd_addr_t sm_address_resolution_address; 255 static void * sm_address_resolution_context; 256 static address_resolution_mode_t sm_address_resolution_mode; 257 static btstack_linked_list_t sm_address_resolution_general_queue; 258 259 // aes128 crypto engine. 260 static sm_aes128_state_t sm_aes128_state; 261 262 // crypto 263 static btstack_crypto_random_t sm_crypto_random_request; 264 static btstack_crypto_aes128_t sm_crypto_aes128_request; 265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 266 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 267 #endif 268 269 // temp storage for random data 270 static uint8_t sm_random_data[8]; 271 static uint8_t sm_aes128_key[16]; 272 static uint8_t sm_aes128_plaintext[16]; 273 static uint8_t sm_aes128_ciphertext[16]; 274 275 // to receive hci events 276 static btstack_packet_callback_registration_t hci_event_callback_registration; 277 278 /* to dispatch sm event */ 279 static btstack_linked_list_t sm_event_handlers; 280 281 /* to schedule calls to sm_run */ 282 static btstack_timer_source_t sm_run_timer; 283 284 // LE Secure Connections 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 static ec_key_generation_state_t ec_key_generation_state; 287 static uint8_t ec_q[64]; 288 #endif 289 290 // 291 // Volume 3, Part H, Chapter 24 292 // "Security shall be initiated by the Security Manager in the device in the master role. 293 // The device in the slave role shall be the responding device." 294 // -> master := initiator, slave := responder 295 // 296 297 // data needed for security setup 298 typedef struct sm_setup_context { 299 300 btstack_timer_source_t sm_timeout; 301 302 // used in all phases 303 uint8_t sm_pairing_failed_reason; 304 305 // user response, (Phase 1 and/or 2) 306 uint8_t sm_user_response; 307 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 308 309 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 310 uint8_t sm_key_distribution_send_set; 311 uint8_t sm_key_distribution_sent_set; 312 uint8_t sm_key_distribution_received_set; 313 314 // Phase 2 (Pairing over SMP) 315 stk_generation_method_t sm_stk_generation_method; 316 sm_key_t sm_tk; 317 uint8_t sm_have_oob_data; 318 uint8_t sm_use_secure_connections; 319 320 sm_key_t sm_c1_t3_value; // c1 calculation 321 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 322 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 323 sm_key_t sm_local_random; 324 sm_key_t sm_local_confirm; 325 sm_key_t sm_peer_random; 326 sm_key_t sm_peer_confirm; 327 uint8_t sm_m_addr_type; // address and type can be removed 328 uint8_t sm_s_addr_type; // '' 329 bd_addr_t sm_m_address; // '' 330 bd_addr_t sm_s_address; // '' 331 sm_key_t sm_ltk; 332 333 uint8_t sm_state_vars; 334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 335 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 336 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 337 sm_key_t sm_local_nonce; // might be combined with sm_local_random 338 uint8_t sm_dhkey[32]; 339 sm_key_t sm_peer_dhkey_check; 340 sm_key_t sm_local_dhkey_check; 341 sm_key_t sm_ra; 342 sm_key_t sm_rb; 343 sm_key_t sm_t; // used for f5 and h6 344 sm_key_t sm_mackey; 345 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 346 #endif 347 348 // Phase 3 349 350 // key distribution, we generate 351 uint16_t sm_local_y; 352 uint16_t sm_local_div; 353 uint16_t sm_local_ediv; 354 uint8_t sm_local_rand[8]; 355 sm_key_t sm_local_ltk; 356 sm_key_t sm_local_csrk; 357 sm_key_t sm_local_irk; 358 // sm_local_address/addr_type not needed 359 360 // key distribution, received from peer 361 uint16_t sm_peer_y; 362 uint16_t sm_peer_div; 363 uint16_t sm_peer_ediv; 364 uint8_t sm_peer_rand[8]; 365 sm_key_t sm_peer_ltk; 366 sm_key_t sm_peer_irk; 367 sm_key_t sm_peer_csrk; 368 uint8_t sm_peer_addr_type; 369 bd_addr_t sm_peer_address; 370 #ifdef ENABLE_LE_SIGNED_WRITE 371 int sm_le_device_index; 372 #endif 373 374 } sm_setup_context_t; 375 376 // 377 static sm_setup_context_t the_setup; 378 static sm_setup_context_t * setup = &the_setup; 379 380 // active connection - the one for which the_setup is used for 381 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 382 383 // @returns 1 if oob data is available 384 // stores oob data in provided 16 byte buffer if not null 385 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 386 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); 387 388 static void sm_run(void); 389 static void sm_done_for_handle(hci_con_handle_t con_handle); 390 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 391 static inline int sm_calc_actual_encryption_key_size(int other); 392 static int sm_validate_stk_generation_method(void); 393 static void sm_handle_encryption_result_address_resolution(void *arg); 394 static void sm_handle_encryption_result_dkg_dhk(void *arg); 395 static void sm_handle_encryption_result_dkg_irk(void *arg); 396 static void sm_handle_encryption_result_enc_a(void *arg); 397 static void sm_handle_encryption_result_enc_b(void *arg); 398 static void sm_handle_encryption_result_enc_c(void *arg); 399 static void sm_handle_encryption_result_enc_csrk(void *arg); 400 static void sm_handle_encryption_result_enc_d(void * arg); 401 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 402 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 403 #ifdef ENABLE_LE_PERIPHERAL 404 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 405 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 406 #endif 407 static void sm_handle_encryption_result_enc_stk(void *arg); 408 static void sm_handle_encryption_result_rau(void *arg); 409 static void sm_handle_random_result_ph2_tk(void * arg); 410 static void sm_handle_random_result_rau(void * arg); 411 #ifdef ENABLE_LE_SECURE_CONNECTIONS 412 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)); 413 static void sm_ec_generate_new_key(void); 414 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 415 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 416 static int sm_passkey_entry(stk_generation_method_t method); 417 #endif 418 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 419 420 static void log_info_hex16(const char * name, uint16_t value){ 421 log_info("%-6s 0x%04x", name, value); 422 } 423 424 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 425 // return packet[0]; 426 // } 427 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 428 return packet[1]; 429 } 430 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 431 return packet[2]; 432 } 433 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 434 return packet[3]; 435 } 436 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 437 return packet[4]; 438 } 439 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 440 return packet[5]; 441 } 442 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 443 return packet[6]; 444 } 445 446 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 447 packet[0] = code; 448 } 449 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 450 packet[1] = io_capability; 451 } 452 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 453 packet[2] = oob_data_flag; 454 } 455 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 456 packet[3] = auth_req; 457 } 458 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 459 packet[4] = max_encryption_key_size; 460 } 461 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 462 packet[5] = initiator_key_distribution; 463 } 464 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 465 packet[6] = responder_key_distribution; 466 } 467 468 // @returns 1 if all bytes are 0 469 static int sm_is_null(uint8_t * data, int size){ 470 int i; 471 for (i=0; i < size ; i++){ 472 if (data[i] != 0) { 473 return 0; 474 } 475 } 476 return 1; 477 } 478 479 static int sm_is_null_random(uint8_t random[8]){ 480 return sm_is_null(random, 8); 481 } 482 483 static int sm_is_null_key(uint8_t * key){ 484 return sm_is_null(key, 16); 485 } 486 487 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 488 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 489 UNUSED(ts); 490 sm_run(); 491 } 492 static void sm_trigger_run(void){ 493 (void)btstack_run_loop_remove_timer(&sm_run_timer); 494 btstack_run_loop_set_timer(&sm_run_timer, 0); 495 btstack_run_loop_add_timer(&sm_run_timer); 496 } 497 498 // Key utils 499 static void sm_reset_tk(void){ 500 int i; 501 for (i=0;i<16;i++){ 502 setup->sm_tk[i] = 0; 503 } 504 } 505 506 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 507 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 508 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 509 int i; 510 for (i = max_encryption_size ; i < 16 ; i++){ 511 key[15-i] = 0; 512 } 513 } 514 515 // ER / IR checks 516 static void sm_er_ir_set_default(void){ 517 int i; 518 for (i=0;i<16;i++){ 519 sm_persistent_er[i] = 0x30 + i; 520 sm_persistent_ir[i] = 0x90 + i; 521 } 522 } 523 524 static int sm_er_is_default(void){ 525 int i; 526 for (i=0;i<16;i++){ 527 if (sm_persistent_er[i] != (0x30+i)) return 0; 528 } 529 return 1; 530 } 531 532 static int sm_ir_is_default(void){ 533 int i; 534 for (i=0;i<16;i++){ 535 if (sm_persistent_ir[i] != (0x90+i)) return 0; 536 } 537 return 1; 538 } 539 540 // SMP Timeout implementation 541 542 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 543 // the Security Manager Timer shall be reset and started. 544 // 545 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 546 // 547 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 548 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 549 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 550 // established. 551 552 static void sm_timeout_handler(btstack_timer_source_t * timer){ 553 log_info("SM timeout"); 554 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 555 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 556 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 557 sm_done_for_handle(sm_conn->sm_handle); 558 559 // trigger handling of next ready connection 560 sm_run(); 561 } 562 static void sm_timeout_start(sm_connection_t * sm_conn){ 563 btstack_run_loop_remove_timer(&setup->sm_timeout); 564 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 565 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 566 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 567 btstack_run_loop_add_timer(&setup->sm_timeout); 568 } 569 static void sm_timeout_stop(void){ 570 btstack_run_loop_remove_timer(&setup->sm_timeout); 571 } 572 static void sm_timeout_reset(sm_connection_t * sm_conn){ 573 sm_timeout_stop(); 574 sm_timeout_start(sm_conn); 575 } 576 577 // end of sm timeout 578 579 // GAP Random Address updates 580 static gap_random_address_type_t gap_random_adress_type; 581 static btstack_timer_source_t gap_random_address_update_timer; 582 static uint32_t gap_random_adress_update_period; 583 584 static void gap_random_address_trigger(void){ 585 log_info("gap_random_address_trigger, state %u", rau_state); 586 if (rau_state != RAU_IDLE) return; 587 rau_state = RAU_GET_RANDOM; 588 sm_trigger_run(); 589 } 590 591 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 592 UNUSED(timer); 593 594 log_info("GAP Random Address Update due"); 595 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 596 btstack_run_loop_add_timer(&gap_random_address_update_timer); 597 gap_random_address_trigger(); 598 } 599 600 static void gap_random_address_update_start(void){ 601 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 602 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 603 btstack_run_loop_add_timer(&gap_random_address_update_timer); 604 } 605 606 static void gap_random_address_update_stop(void){ 607 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 608 } 609 610 // ah(k,r) helper 611 // r = padding || r 612 // r - 24 bit value 613 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 614 // r'= padding || r 615 memset(r_prime, 0, 16); 616 (void)memcpy(&r_prime[13], r, 3); 617 } 618 619 // d1 helper 620 // d' = padding || r || d 621 // d,r - 16 bit values 622 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 623 // d'= padding || r || d 624 memset(d1_prime, 0, 16); 625 big_endian_store_16(d1_prime, 12, r); 626 big_endian_store_16(d1_prime, 14, d); 627 } 628 629 // calculate arguments for first AES128 operation in C1 function 630 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){ 631 632 // p1 = pres || preq || rat’ || iat’ 633 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 634 // cant octet of pres becomes the most significant octet of p1. 635 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 636 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 637 // p1 is 0x05000800000302070710000001010001." 638 639 sm_key_t p1; 640 reverse_56(pres, &p1[0]); 641 reverse_56(preq, &p1[7]); 642 p1[14] = rat; 643 p1[15] = iat; 644 log_info_key("p1", p1); 645 log_info_key("r", r); 646 647 // t1 = r xor p1 648 int i; 649 for (i=0;i<16;i++){ 650 t1[i] = r[i] ^ p1[i]; 651 } 652 log_info_key("t1", t1); 653 } 654 655 // calculate arguments for second AES128 operation in C1 function 656 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 657 // p2 = padding || ia || ra 658 // "The least significant octet of ra becomes the least significant octet of p2 and 659 // the most significant octet of padding becomes the most significant octet of p2. 660 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 661 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 662 663 sm_key_t p2; 664 memset(p2, 0, 16); 665 (void)memcpy(&p2[4], ia, 6); 666 (void)memcpy(&p2[10], ra, 6); 667 log_info_key("p2", p2); 668 669 // c1 = e(k, t2_xor_p2) 670 int i; 671 for (i=0;i<16;i++){ 672 t3[i] = t2[i] ^ p2[i]; 673 } 674 log_info_key("t3", t3); 675 } 676 677 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 678 log_info_key("r1", r1); 679 log_info_key("r2", r2); 680 (void)memcpy(&r_prime[8], &r2[8], 8); 681 (void)memcpy(&r_prime[0], &r1[8], 8); 682 } 683 684 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 685 UNUSED(channel); 686 687 // log event 688 hci_dump_packet(packet_type, 1, packet, size); 689 // dispatch to all event handlers 690 btstack_linked_list_iterator_t it; 691 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 692 while (btstack_linked_list_iterator_has_next(&it)){ 693 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 694 entry->callback(packet_type, 0, packet, size); 695 } 696 } 697 698 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){ 699 event[0] = type; 700 event[1] = event_size - 2; 701 little_endian_store_16(event, 2, con_handle); 702 event[4] = addr_type; 703 reverse_bd_addr(address, &event[5]); 704 } 705 706 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 707 uint8_t event[11]; 708 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 709 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 710 } 711 712 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){ 713 uint8_t event[15]; 714 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 715 little_endian_store_32(event, 11, passkey); 716 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 717 } 718 719 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){ 720 // fetch addr and addr type from db, only called for valid entries 721 bd_addr_t identity_address; 722 int identity_address_type; 723 le_device_db_info(index, &identity_address_type, identity_address, NULL); 724 725 uint8_t event[20]; 726 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 727 event[11] = identity_address_type; 728 reverse_bd_addr(identity_address, &event[12]); 729 little_endian_store_16(event, 18, index); 730 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 731 } 732 733 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){ 734 uint8_t event[12]; 735 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 736 event[11] = status; 737 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 738 } 739 740 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 741 uint8_t event[13]; 742 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 743 event[11] = status; 744 event[12] = reason; 745 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 746 } 747 748 // decide on stk generation based on 749 // - pairing request 750 // - io capabilities 751 // - OOB data availability 752 static void sm_setup_tk(void){ 753 754 // horizontal: initiator capabilities 755 // vertial: responder capabilities 756 static const stk_generation_method_t stk_generation_method [5] [5] = { 757 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 758 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 759 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 760 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 761 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 762 }; 763 764 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 765 #ifdef ENABLE_LE_SECURE_CONNECTIONS 766 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 767 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 768 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 769 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 770 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 771 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 772 }; 773 #endif 774 775 // default: just works 776 setup->sm_stk_generation_method = JUST_WORKS; 777 778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 779 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 780 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 781 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 782 #else 783 setup->sm_use_secure_connections = 0; 784 #endif 785 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 786 787 788 // decide if OOB will be used based on SC vs. Legacy and oob flags 789 int use_oob = 0; 790 if (setup->sm_use_secure_connections){ 791 // In LE Secure Connections pairing, the out of band method is used if at least 792 // one device has the peer device's out of band authentication data available. 793 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 794 } else { 795 // In LE legacy pairing, the out of band method is used if both the devices have 796 // the other device's out of band authentication data available. 797 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 798 } 799 if (use_oob){ 800 log_info("SM: have OOB data"); 801 log_info_key("OOB", setup->sm_tk); 802 setup->sm_stk_generation_method = OOB; 803 return; 804 } 805 806 // If both devices have not set the MITM option in the Authentication Requirements 807 // Flags, then the IO capabilities shall be ignored and the Just Works association 808 // model shall be used. 809 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 810 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 811 log_info("SM: MITM not required by both -> JUST WORKS"); 812 return; 813 } 814 815 // Reset TK as it has been setup in sm_init_setup 816 sm_reset_tk(); 817 818 // Also use just works if unknown io capabilites 819 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)){ 820 return; 821 } 822 823 // Otherwise the IO capabilities of the devices shall be used to determine the 824 // pairing method as defined in Table 2.4. 825 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 826 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 827 828 #ifdef ENABLE_LE_SECURE_CONNECTIONS 829 // table not define by default 830 if (setup->sm_use_secure_connections){ 831 generation_method = stk_generation_method_with_secure_connection; 832 } 833 #endif 834 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)]; 835 836 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 837 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); 838 } 839 840 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 841 int flags = 0; 842 if (key_set & SM_KEYDIST_ENC_KEY){ 843 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 844 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 845 } 846 if (key_set & SM_KEYDIST_ID_KEY){ 847 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 848 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 849 } 850 if (key_set & SM_KEYDIST_SIGN){ 851 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 852 } 853 return flags; 854 } 855 856 static void sm_setup_key_distribution(uint8_t key_set){ 857 setup->sm_key_distribution_received_set = 0; 858 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 859 setup->sm_key_distribution_sent_set = 0; 860 #ifdef ENABLE_LE_SIGNED_WRITE 861 setup->sm_le_device_index = -1; 862 #endif 863 } 864 865 // CSRK Key Lookup 866 867 868 static int sm_address_resolution_idle(void){ 869 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 870 } 871 872 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){ 873 (void)memcpy(sm_address_resolution_address, addr, 6); 874 sm_address_resolution_addr_type = addr_type; 875 sm_address_resolution_test = 0; 876 sm_address_resolution_mode = mode; 877 sm_address_resolution_context = context; 878 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 879 } 880 881 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 882 // check if already in list 883 btstack_linked_list_iterator_t it; 884 sm_lookup_entry_t * entry; 885 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 886 while(btstack_linked_list_iterator_has_next(&it)){ 887 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 888 if (entry->address_type != address_type) continue; 889 if (memcmp(entry->address, address, 6)) continue; 890 // already in list 891 return BTSTACK_BUSY; 892 } 893 entry = btstack_memory_sm_lookup_entry_get(); 894 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 895 entry->address_type = (bd_addr_type_t) address_type; 896 (void)memcpy(entry->address, address, 6); 897 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 898 sm_trigger_run(); 899 return 0; 900 } 901 902 // CMAC calculation using AES Engineq 903 #ifdef USE_CMAC_ENGINE 904 905 static void sm_cmac_done_trampoline(void * arg){ 906 UNUSED(arg); 907 sm_cmac_active = 0; 908 (*sm_cmac_done_callback)(sm_cmac_hash); 909 sm_trigger_run(); 910 } 911 912 int sm_cmac_ready(void){ 913 return sm_cmac_active == 0u; 914 } 915 #endif 916 917 #ifdef ENABLE_LE_SECURE_CONNECTIONS 918 // generic cmac calculation 919 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)){ 920 sm_cmac_active = 1; 921 sm_cmac_done_callback = done_callback; 922 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 923 } 924 #endif 925 926 // cmac for ATT Message signing 927 #ifdef ENABLE_LE_SIGNED_WRITE 928 929 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)){ 930 sm_cmac_active = 1; 931 sm_cmac_done_callback = done_callback; 932 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 933 } 934 935 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 936 if (offset >= sm_cmac_signed_write_message_len) { 937 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 938 return 0; 939 } 940 941 offset = sm_cmac_signed_write_message_len - 1 - offset; 942 943 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 944 if (offset < 3){ 945 return sm_cmac_signed_write_header[offset]; 946 } 947 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 948 if (offset < actual_message_len_incl_header){ 949 return sm_cmac_signed_write_message[offset - 3]; 950 } 951 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 952 } 953 954 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)){ 955 // ATT Message Signing 956 sm_cmac_signed_write_header[0] = opcode; 957 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 958 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 959 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 960 sm_cmac_signed_write_message = message; 961 sm_cmac_signed_write_message_len = total_message_len; 962 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 963 } 964 #endif 965 966 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 967 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 968 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 969 switch (setup->sm_stk_generation_method){ 970 case PK_RESP_INPUT: 971 if (IS_RESPONDER(sm_conn->sm_role)){ 972 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 973 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 974 } else { 975 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)); 976 } 977 break; 978 case PK_INIT_INPUT: 979 if (IS_RESPONDER(sm_conn->sm_role)){ 980 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)); 981 } else { 982 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 983 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 984 } 985 break; 986 case PK_BOTH_INPUT: 987 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 988 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 989 break; 990 case NUMERIC_COMPARISON: 991 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 992 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)); 993 break; 994 case JUST_WORKS: 995 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 996 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 997 break; 998 case OOB: 999 // client already provided OOB data, let's skip notification. 1000 break; 1001 default: 1002 btstack_assert(false); 1003 break; 1004 } 1005 } 1006 1007 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1008 int recv_flags; 1009 if (IS_RESPONDER(sm_conn->sm_role)){ 1010 // slave / responder 1011 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1012 } else { 1013 // master / initiator 1014 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1015 } 1016 1017 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1018 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1019 if (setup->sm_use_secure_connections){ 1020 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1021 } 1022 #endif 1023 1024 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1025 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1026 } 1027 1028 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1029 if (sm_active_connection_handle == con_handle){ 1030 sm_timeout_stop(); 1031 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1032 log_info("sm: connection 0x%x released setup context", con_handle); 1033 1034 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1035 // generate new ec key after each pairing (that used it) 1036 if (setup->sm_use_secure_connections){ 1037 sm_ec_generate_new_key(); 1038 } 1039 #endif 1040 } 1041 } 1042 1043 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1044 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1045 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1046 sm_done_for_handle(connection->sm_handle); 1047 } 1048 1049 static int sm_key_distribution_flags_for_auth_req(void){ 1050 1051 int flags = SM_KEYDIST_ID_KEY; 1052 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1053 // encryption and signing information only if bonding requested 1054 flags |= SM_KEYDIST_ENC_KEY; 1055 #ifdef ENABLE_LE_SIGNED_WRITE 1056 flags |= SM_KEYDIST_SIGN; 1057 #endif 1058 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1059 // LinkKey for CTKD requires SC 1060 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1061 flags |= SM_KEYDIST_LINK_KEY; 1062 } 1063 #endif 1064 } 1065 return flags; 1066 } 1067 1068 static void sm_reset_setup(void){ 1069 // fill in sm setup 1070 setup->sm_state_vars = 0; 1071 setup->sm_keypress_notification = 0; 1072 sm_reset_tk(); 1073 } 1074 1075 static void sm_init_setup(sm_connection_t * sm_conn){ 1076 1077 // fill in sm setup 1078 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1079 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1080 1081 // query client for Legacy Pairing OOB data 1082 setup->sm_have_oob_data = 0; 1083 if (sm_get_oob_data) { 1084 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1085 } 1086 1087 // if available and SC supported, also ask for SC OOB Data 1088 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1089 memset(setup->sm_ra, 0, 16); 1090 memset(setup->sm_rb, 0, 16); 1091 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1092 if (sm_get_sc_oob_data){ 1093 if (IS_RESPONDER(sm_conn->sm_role)){ 1094 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1095 sm_conn->sm_peer_addr_type, 1096 sm_conn->sm_peer_address, 1097 setup->sm_peer_confirm, 1098 setup->sm_ra); 1099 } else { 1100 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1101 sm_conn->sm_peer_addr_type, 1102 sm_conn->sm_peer_address, 1103 setup->sm_peer_confirm, 1104 setup->sm_rb); 1105 } 1106 } else { 1107 setup->sm_have_oob_data = 0; 1108 } 1109 } 1110 #endif 1111 1112 sm_pairing_packet_t * local_packet; 1113 if (IS_RESPONDER(sm_conn->sm_role)){ 1114 // slave 1115 local_packet = &setup->sm_s_pres; 1116 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1117 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1118 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1119 } else { 1120 // master 1121 local_packet = &setup->sm_m_preq; 1122 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1123 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1124 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1125 1126 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1127 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1128 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1129 } 1130 1131 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1132 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1133 // set CT2 if SC + Bonding + CTKD 1134 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1135 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1136 auth_req |= SM_AUTHREQ_CT2; 1137 } 1138 #endif 1139 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1140 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1141 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1142 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1143 } 1144 1145 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1146 1147 sm_pairing_packet_t * remote_packet; 1148 int remote_key_request; 1149 if (IS_RESPONDER(sm_conn->sm_role)){ 1150 // slave / responder 1151 remote_packet = &setup->sm_m_preq; 1152 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1153 } else { 1154 // master / initiator 1155 remote_packet = &setup->sm_s_pres; 1156 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1157 } 1158 1159 // check key size 1160 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1161 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1162 1163 // decide on STK generation method / SC 1164 sm_setup_tk(); 1165 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1166 1167 // check if STK generation method is acceptable by client 1168 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1169 1170 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1171 // check LE SC Only mode 1172 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1173 log_info("SC Only mode active but SC not possible"); 1174 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1175 } 1176 1177 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1178 if (setup->sm_use_secure_connections){ 1179 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1180 } 1181 #endif 1182 1183 // identical to responder 1184 sm_setup_key_distribution(remote_key_request); 1185 1186 // JUST WORKS doens't provide authentication 1187 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1188 1189 return 0; 1190 } 1191 1192 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1193 1194 // cache and reset context 1195 int matched_device_id = sm_address_resolution_test; 1196 address_resolution_mode_t mode = sm_address_resolution_mode; 1197 void * context = sm_address_resolution_context; 1198 1199 // reset context 1200 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1201 sm_address_resolution_context = NULL; 1202 sm_address_resolution_test = -1; 1203 hci_con_handle_t con_handle = 0; 1204 1205 sm_connection_t * sm_connection; 1206 sm_key_t ltk; 1207 int have_ltk; 1208 #ifdef ENABLE_LE_CENTRAL 1209 int trigger_pairing; 1210 #endif 1211 switch (mode){ 1212 case ADDRESS_RESOLUTION_GENERAL: 1213 break; 1214 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1215 sm_connection = (sm_connection_t *) context; 1216 con_handle = sm_connection->sm_handle; 1217 1218 // have ltk -> start encryption / send security request 1219 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1220 // "When a bond has been created between two devices, any reconnection should result in the local device 1221 // enabling or requesting encryption with the remote device before initiating any service request." 1222 1223 switch (event){ 1224 case ADDRESS_RESOLUTION_SUCCEEDED: 1225 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1226 sm_connection->sm_le_db_index = matched_device_id; 1227 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1228 1229 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1230 have_ltk = !sm_is_null_key(ltk); 1231 1232 if (sm_connection->sm_role) { 1233 1234 #ifdef ENABLE_LE_PERIPHERAL 1235 1236 // LTK request received before, IRK required -> start LTK calculation 1237 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1238 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1239 break; 1240 } 1241 1242 if (have_ltk) { 1243 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1244 log_info("central: enable encryption for bonded device"); 1245 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1246 sm_trigger_run(); 1247 #else 1248 log_info("central: defer security request for bonded device"); 1249 #endif 1250 } 1251 #endif 1252 } else { 1253 1254 #ifdef ENABLE_LE_CENTRAL 1255 1256 // check if pairing already requested and reset requests 1257 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1258 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1259 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, trigger_pairing, have_ltk); 1260 sm_connection->sm_security_request_received = 0; 1261 sm_connection->sm_pairing_requested = 0; 1262 1263 if (have_ltk){ 1264 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1265 log_info("central: enable encryption for bonded device"); 1266 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1267 break; 1268 #else 1269 log_info("central: defer enabling encryption for bonded device"); 1270 #endif 1271 } 1272 1273 // pairing_request -> send pairing request 1274 if (trigger_pairing){ 1275 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1276 break; 1277 } 1278 } 1279 #endif 1280 break; 1281 case ADDRESS_RESOLUTION_FAILED: 1282 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1283 if (sm_connection->sm_role) { 1284 // LTK request received before, IRK required -> negative LTK reply 1285 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1286 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1287 } 1288 break; 1289 } 1290 #ifdef ENABLE_LE_CENTRAL 1291 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1292 sm_connection->sm_security_request_received = 0; 1293 sm_connection->sm_pairing_requested = 0; 1294 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1295 #endif 1296 break; 1297 1298 default: 1299 btstack_assert(false); 1300 break; 1301 } 1302 break; 1303 default: 1304 break; 1305 } 1306 1307 switch (event){ 1308 case ADDRESS_RESOLUTION_SUCCEEDED: 1309 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1310 break; 1311 case ADDRESS_RESOLUTION_FAILED: 1312 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1313 break; 1314 default: 1315 btstack_assert(false); 1316 break; 1317 } 1318 } 1319 1320 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1321 1322 int le_db_index = -1; 1323 1324 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1325 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1326 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1327 & SM_AUTHREQ_BONDING ) != 0u; 1328 1329 if (bonding_enabed){ 1330 1331 // lookup device based on IRK 1332 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1333 int i; 1334 for (i=0; i < le_device_db_max_count(); i++){ 1335 sm_key_t irk; 1336 bd_addr_t address; 1337 int address_type = BD_ADDR_TYPE_UNKNOWN; 1338 le_device_db_info(i, &address_type, address, irk); 1339 // skip unused entries 1340 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1341 // compare IRK 1342 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1343 1344 log_info("sm: device found for IRK, updating"); 1345 le_db_index = i; 1346 break; 1347 } 1348 } else { 1349 // assert IRK is set to zero 1350 memset(setup->sm_peer_irk, 0, 16); 1351 } 1352 1353 // if not found, lookup via public address if possible 1354 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1355 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1356 int i; 1357 for (i=0; i < le_device_db_max_count(); i++){ 1358 bd_addr_t address; 1359 int address_type = BD_ADDR_TYPE_UNKNOWN; 1360 le_device_db_info(i, &address_type, address, NULL); 1361 // skip unused entries 1362 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1363 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1364 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1365 log_info("sm: device found for public address, updating"); 1366 le_db_index = i; 1367 break; 1368 } 1369 } 1370 } 1371 1372 // if not found, add to db 1373 bool new_to_le_device_db = false; 1374 if (le_db_index < 0) { 1375 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1376 new_to_le_device_db = true; 1377 } 1378 1379 if (le_db_index >= 0){ 1380 1381 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1382 if (!new_to_le_device_db){ 1383 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1384 } 1385 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1386 #else 1387 UNUSED(new_to_le_device_db); 1388 #endif 1389 1390 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1391 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1392 1393 #ifdef ENABLE_LE_SIGNED_WRITE 1394 // store local CSRK 1395 setup->sm_le_device_index = le_db_index; 1396 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1397 log_info("sm: store local CSRK"); 1398 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1399 le_device_db_local_counter_set(le_db_index, 0); 1400 } 1401 1402 // store remote CSRK 1403 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1404 log_info("sm: store remote CSRK"); 1405 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1406 le_device_db_remote_counter_set(le_db_index, 0); 1407 } 1408 #endif 1409 // store encryption information for secure connections: LTK generated by ECDH 1410 if (setup->sm_use_secure_connections){ 1411 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1412 uint8_t zero_rand[8]; 1413 memset(zero_rand, 0, 8); 1414 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1415 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1416 } 1417 1418 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1419 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1420 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1421 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1422 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1423 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1424 1425 } 1426 } 1427 } else { 1428 log_info("Ignoring received keys, bonding not enabled"); 1429 } 1430 1431 // keep le_db_index 1432 sm_conn->sm_le_db_index = le_db_index; 1433 } 1434 1435 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1436 setup->sm_pairing_failed_reason = reason; 1437 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1438 } 1439 1440 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1441 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1442 } 1443 1444 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1445 1446 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1447 static int sm_passkey_used(stk_generation_method_t method); 1448 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1449 1450 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1451 if (setup->sm_stk_generation_method == OOB){ 1452 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1453 } else { 1454 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_w2_cmac_for_confirmation, (void *)(uintptr_t) sm_conn->sm_handle); 1455 } 1456 } 1457 1458 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1459 if (IS_RESPONDER(sm_conn->sm_role)){ 1460 // Responder 1461 if (setup->sm_stk_generation_method == OOB){ 1462 // generate Nb 1463 log_info("Generate Nb"); 1464 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void *)(uintptr_t) sm_conn->sm_handle); 1465 } else { 1466 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1467 } 1468 } else { 1469 // Initiator role 1470 switch (setup->sm_stk_generation_method){ 1471 case JUST_WORKS: 1472 sm_sc_prepare_dhkey_check(sm_conn); 1473 break; 1474 1475 case NUMERIC_COMPARISON: 1476 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1477 break; 1478 case PK_INIT_INPUT: 1479 case PK_RESP_INPUT: 1480 case PK_BOTH_INPUT: 1481 if (setup->sm_passkey_bit < 20u) { 1482 sm_sc_start_calculating_local_confirm(sm_conn); 1483 } else { 1484 sm_sc_prepare_dhkey_check(sm_conn); 1485 } 1486 break; 1487 case OOB: 1488 sm_sc_prepare_dhkey_check(sm_conn); 1489 break; 1490 default: 1491 btstack_assert(false); 1492 break; 1493 } 1494 } 1495 } 1496 1497 static void sm_sc_cmac_done(uint8_t * hash){ 1498 log_info("sm_sc_cmac_done: "); 1499 log_info_hexdump(hash, 16); 1500 1501 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1502 sm_sc_oob_state = SM_SC_OOB_IDLE; 1503 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1504 return; 1505 } 1506 1507 sm_connection_t * sm_conn = sm_cmac_connection; 1508 sm_cmac_connection = NULL; 1509 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1510 link_key_type_t link_key_type; 1511 #endif 1512 1513 switch (sm_conn->sm_engine_state){ 1514 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1515 (void)memcpy(setup->sm_local_confirm, hash, 16); 1516 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1517 break; 1518 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1519 // check 1520 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1521 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1522 break; 1523 } 1524 sm_sc_state_after_receiving_random(sm_conn); 1525 break; 1526 case SM_SC_W4_CALCULATE_G2: { 1527 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1528 big_endian_store_32(setup->sm_tk, 12, vab); 1529 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1530 sm_trigger_user_response(sm_conn); 1531 break; 1532 } 1533 case SM_SC_W4_CALCULATE_F5_SALT: 1534 (void)memcpy(setup->sm_t, hash, 16); 1535 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1536 break; 1537 case SM_SC_W4_CALCULATE_F5_MACKEY: 1538 (void)memcpy(setup->sm_mackey, hash, 16); 1539 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1540 break; 1541 case SM_SC_W4_CALCULATE_F5_LTK: 1542 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1543 // Errata Service Release to the Bluetooth Specification: ESR09 1544 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1545 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1546 (void)memcpy(setup->sm_ltk, hash, 16); 1547 (void)memcpy(setup->sm_local_ltk, hash, 16); 1548 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1549 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1550 break; 1551 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1552 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1553 if (IS_RESPONDER(sm_conn->sm_role)){ 1554 // responder 1555 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1556 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1557 } else { 1558 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1559 } 1560 } else { 1561 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1562 } 1563 break; 1564 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1565 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1566 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1567 break; 1568 } 1569 if (IS_RESPONDER(sm_conn->sm_role)){ 1570 // responder 1571 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1572 } else { 1573 // initiator 1574 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1575 } 1576 break; 1577 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1578 case SM_SC_W4_CALCULATE_ILK: 1579 (void)memcpy(setup->sm_t, hash, 16); 1580 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1581 break; 1582 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1583 reverse_128(hash, setup->sm_t); 1584 link_key_type = sm_conn->sm_connection_authenticated ? 1585 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1586 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1587 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1588 if (IS_RESPONDER(sm_conn->sm_role)){ 1589 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1590 } else { 1591 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1592 } 1593 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1594 sm_done_for_handle(sm_conn->sm_handle); 1595 break; 1596 #endif 1597 default: 1598 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1599 break; 1600 } 1601 sm_trigger_run(); 1602 } 1603 1604 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){ 1605 const uint16_t message_len = 65; 1606 sm_cmac_connection = sm_conn; 1607 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1608 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1609 sm_cmac_sc_buffer[64] = z; 1610 log_info("f4 key"); 1611 log_info_hexdump(x, 16); 1612 log_info("f4 message"); 1613 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1614 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1615 } 1616 1617 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1618 static const uint8_t f5_length[] = { 0x01, 0x00}; 1619 1620 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1621 1622 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1623 1624 log_info("f5_calculate_salt"); 1625 // calculate salt for f5 1626 const uint16_t message_len = 32; 1627 sm_cmac_connection = sm_conn; 1628 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1629 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1630 } 1631 1632 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){ 1633 const uint16_t message_len = 53; 1634 sm_cmac_connection = sm_conn; 1635 1636 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1637 sm_cmac_sc_buffer[0] = 0; 1638 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1639 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1640 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1641 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1642 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1643 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1644 log_info("f5 key"); 1645 log_info_hexdump(t, 16); 1646 log_info("f5 message for MacKey"); 1647 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1648 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1649 } 1650 1651 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1652 sm_key56_t bd_addr_master, bd_addr_slave; 1653 bd_addr_master[0] = setup->sm_m_addr_type; 1654 bd_addr_slave[0] = setup->sm_s_addr_type; 1655 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1656 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1657 if (IS_RESPONDER(sm_conn->sm_role)){ 1658 // responder 1659 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1660 } else { 1661 // initiator 1662 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1663 } 1664 } 1665 1666 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1667 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1668 const uint16_t message_len = 53; 1669 sm_cmac_connection = sm_conn; 1670 sm_cmac_sc_buffer[0] = 1; 1671 // 1..52 setup before 1672 log_info("f5 key"); 1673 log_info_hexdump(t, 16); 1674 log_info("f5 message for LTK"); 1675 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1676 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1677 } 1678 1679 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1680 f5_ltk(sm_conn, setup->sm_t); 1681 } 1682 1683 static void f6_setup(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){ 1684 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1685 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1686 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1687 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1688 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1689 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1690 } 1691 1692 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1693 const uint16_t message_len = 65; 1694 sm_cmac_connection = sm_conn; 1695 log_info("f6 key"); 1696 log_info_hexdump(w, 16); 1697 log_info("f6 message"); 1698 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1699 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1700 } 1701 1702 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1703 // - U is 256 bits 1704 // - V is 256 bits 1705 // - X is 128 bits 1706 // - Y is 128 bits 1707 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){ 1708 const uint16_t message_len = 80; 1709 sm_cmac_connection = sm_conn; 1710 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1711 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1712 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1713 log_info("g2 key"); 1714 log_info_hexdump(x, 16); 1715 log_info("g2 message"); 1716 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1717 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1718 } 1719 1720 static void g2_calculate(sm_connection_t * sm_conn) { 1721 // calc Va if numeric comparison 1722 if (IS_RESPONDER(sm_conn->sm_role)){ 1723 // responder 1724 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1725 } else { 1726 // initiator 1727 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1728 } 1729 } 1730 1731 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1732 uint8_t z = 0; 1733 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1734 // some form of passkey 1735 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1736 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1737 setup->sm_passkey_bit++; 1738 } 1739 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1740 } 1741 1742 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1743 // OOB 1744 if (setup->sm_stk_generation_method == OOB){ 1745 if (IS_RESPONDER(sm_conn->sm_role)){ 1746 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1747 } else { 1748 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1749 } 1750 return; 1751 } 1752 1753 uint8_t z = 0; 1754 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1755 // some form of passkey 1756 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1757 // sm_passkey_bit was increased before sending confirm value 1758 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1759 } 1760 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1761 } 1762 1763 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1764 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1765 1766 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1767 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1768 return; 1769 } else { 1770 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1771 } 1772 } 1773 1774 static void sm_sc_dhkey_calculated(void * arg){ 1775 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1776 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1777 if (sm_conn == NULL) return; 1778 1779 log_info("dhkey"); 1780 log_info_hexdump(&setup->sm_dhkey[0], 32); 1781 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1782 // trigger next step 1783 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1784 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1785 } 1786 sm_trigger_run(); 1787 } 1788 1789 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1790 // calculate DHKCheck 1791 sm_key56_t bd_addr_master, bd_addr_slave; 1792 bd_addr_master[0] = setup->sm_m_addr_type; 1793 bd_addr_slave[0] = setup->sm_s_addr_type; 1794 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1795 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1796 uint8_t iocap_a[3]; 1797 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1798 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1799 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1800 uint8_t iocap_b[3]; 1801 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1802 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1803 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1804 if (IS_RESPONDER(sm_conn->sm_role)){ 1805 // responder 1806 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1807 f6_engine(sm_conn, setup->sm_mackey); 1808 } else { 1809 // initiator 1810 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1811 f6_engine(sm_conn, setup->sm_mackey); 1812 } 1813 } 1814 1815 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1816 // validate E = f6() 1817 sm_key56_t bd_addr_master, bd_addr_slave; 1818 bd_addr_master[0] = setup->sm_m_addr_type; 1819 bd_addr_slave[0] = setup->sm_s_addr_type; 1820 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1821 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1822 1823 uint8_t iocap_a[3]; 1824 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1825 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1826 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1827 uint8_t iocap_b[3]; 1828 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1829 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1830 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1831 if (IS_RESPONDER(sm_conn->sm_role)){ 1832 // responder 1833 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1834 f6_engine(sm_conn, setup->sm_mackey); 1835 } else { 1836 // initiator 1837 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1838 f6_engine(sm_conn, setup->sm_mackey); 1839 } 1840 } 1841 1842 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1843 1844 // 1845 // Link Key Conversion Function h6 1846 // 1847 // h6(W, keyID) = AES-CMAC_W(keyID) 1848 // - W is 128 bits 1849 // - keyID is 32 bits 1850 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1851 const uint16_t message_len = 4; 1852 sm_cmac_connection = sm_conn; 1853 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1854 log_info("h6 key"); 1855 log_info_hexdump(w, 16); 1856 log_info("h6 message"); 1857 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1858 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1859 } 1860 // 1861 // Link Key Conversion Function h7 1862 // 1863 // h7(SALT, W) = AES-CMAC_SALT(W) 1864 // - SALT is 128 bits 1865 // - W is 128 bits 1866 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1867 const uint16_t message_len = 16; 1868 sm_cmac_connection = sm_conn; 1869 log_info("h7 key"); 1870 log_info_hexdump(salt, 16); 1871 log_info("h7 message"); 1872 log_info_hexdump(w, 16); 1873 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1874 } 1875 1876 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1877 // Errata Service Release to the Bluetooth Specification: ESR09 1878 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1879 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1880 1881 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1882 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1883 } 1884 1885 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1886 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1887 } 1888 1889 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1890 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1891 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1892 } 1893 #endif 1894 1895 #endif 1896 1897 // key management legacy connections: 1898 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1899 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1900 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1901 // - responder reconnects: responder uses LTK receveived from master 1902 1903 // key management secure connections: 1904 // - both devices store same LTK from ECDH key exchange. 1905 1906 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1907 static void sm_load_security_info(sm_connection_t * sm_connection){ 1908 int encryption_key_size; 1909 int authenticated; 1910 int authorized; 1911 int secure_connection; 1912 1913 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1914 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1915 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1916 log_info("db index %u, key size %u, authenticated %u, authorized %u, secure connetion %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized, secure_connection); 1917 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1918 sm_connection->sm_connection_authenticated = authenticated; 1919 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1920 sm_connection->sm_connection_sc = secure_connection; 1921 } 1922 #endif 1923 1924 #ifdef ENABLE_LE_PERIPHERAL 1925 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1926 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1927 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1928 // re-establish used key encryption size 1929 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1930 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1931 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1932 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1933 // Legacy paring -> not SC 1934 sm_connection->sm_connection_sc = 0; 1935 log_info("sm: received ltk request with key size %u, authenticated %u", 1936 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1937 } 1938 #endif 1939 1940 // distributed key generation 1941 static bool sm_run_dpkg(void){ 1942 switch (dkg_state){ 1943 case DKG_CALC_IRK: 1944 // already busy? 1945 if (sm_aes128_state == SM_AES128_IDLE) { 1946 log_info("DKG_CALC_IRK started"); 1947 // IRK = d1(IR, 1, 0) 1948 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1949 sm_aes128_state = SM_AES128_ACTIVE; 1950 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1951 return true; 1952 } 1953 break; 1954 case DKG_CALC_DHK: 1955 // already busy? 1956 if (sm_aes128_state == SM_AES128_IDLE) { 1957 log_info("DKG_CALC_DHK started"); 1958 // DHK = d1(IR, 3, 0) 1959 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1960 sm_aes128_state = SM_AES128_ACTIVE; 1961 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1962 return true; 1963 } 1964 break; 1965 default: 1966 break; 1967 } 1968 return false; 1969 } 1970 1971 // random address updates 1972 static bool sm_run_rau(void){ 1973 switch (rau_state){ 1974 case RAU_GET_RANDOM: 1975 rau_state = RAU_W4_RANDOM; 1976 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1977 return true; 1978 case RAU_GET_ENC: 1979 // already busy? 1980 if (sm_aes128_state == SM_AES128_IDLE) { 1981 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1982 sm_aes128_state = SM_AES128_ACTIVE; 1983 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1984 return true; 1985 } 1986 break; 1987 case RAU_SET_ADDRESS: 1988 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1989 rau_state = RAU_IDLE; 1990 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1991 return true; 1992 default: 1993 break; 1994 } 1995 return false; 1996 } 1997 1998 // CSRK Lookup 1999 static bool sm_run_csrk(void){ 2000 btstack_linked_list_iterator_t it; 2001 2002 // -- if csrk lookup ready, find connection that require csrk lookup 2003 if (sm_address_resolution_idle()){ 2004 hci_connections_get_iterator(&it); 2005 while(btstack_linked_list_iterator_has_next(&it)){ 2006 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2007 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2008 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2009 // and start lookup 2010 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); 2011 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2012 break; 2013 } 2014 } 2015 } 2016 2017 // -- if csrk lookup ready, resolved addresses for received addresses 2018 if (sm_address_resolution_idle()) { 2019 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2020 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2021 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2022 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2023 btstack_memory_sm_lookup_entry_free(entry); 2024 } 2025 } 2026 2027 // -- Continue with CSRK device lookup by public or resolvable private address 2028 if (!sm_address_resolution_idle()){ 2029 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2030 while (sm_address_resolution_test < le_device_db_max_count()){ 2031 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2032 bd_addr_t addr; 2033 sm_key_t irk; 2034 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2035 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2036 2037 // skip unused entries 2038 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2039 sm_address_resolution_test++; 2040 continue; 2041 } 2042 2043 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2044 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2045 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2046 break; 2047 } 2048 2049 // if connection type is public, it must be a different one 2050 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2051 sm_address_resolution_test++; 2052 continue; 2053 } 2054 2055 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2056 2057 log_info("LE Device Lookup: calculate AH"); 2058 log_info_key("IRK", irk); 2059 2060 (void)memcpy(sm_aes128_key, irk, 16); 2061 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2062 sm_address_resolution_ah_calculation_active = 1; 2063 sm_aes128_state = SM_AES128_ACTIVE; 2064 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2065 return true; 2066 } 2067 2068 if (sm_address_resolution_test >= le_device_db_max_count()){ 2069 log_info("LE Device Lookup: not found"); 2070 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2071 } 2072 } 2073 return false; 2074 } 2075 2076 // SC OOB 2077 static bool sm_run_oob(void){ 2078 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2079 switch (sm_sc_oob_state){ 2080 case SM_SC_OOB_W2_CALC_CONFIRM: 2081 if (!sm_cmac_ready()) break; 2082 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2083 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2084 return true; 2085 default: 2086 break; 2087 } 2088 #endif 2089 return false; 2090 } 2091 2092 // handle basic actions that don't requires the full context 2093 static bool sm_run_basic(void){ 2094 btstack_linked_list_iterator_t it; 2095 hci_connections_get_iterator(&it); 2096 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2097 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2098 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2099 switch(sm_connection->sm_engine_state){ 2100 // responder side 2101 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2102 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2103 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2104 return true; 2105 2106 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2107 case SM_SC_RECEIVED_LTK_REQUEST: 2108 switch (sm_connection->sm_irk_lookup_state){ 2109 case IRK_LOOKUP_FAILED: 2110 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2111 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2112 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2113 return true; 2114 default: 2115 break; 2116 } 2117 break; 2118 #endif 2119 default: 2120 break; 2121 } 2122 } 2123 return false; 2124 } 2125 2126 static void sm_run_activate_connection(void){ 2127 // Find connections that requires setup context and make active if no other is locked 2128 btstack_linked_list_iterator_t it; 2129 hci_connections_get_iterator(&it); 2130 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2131 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2132 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2133 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2134 int done = 1; 2135 int err; 2136 UNUSED(err); 2137 2138 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2139 // assert ec key is ready 2140 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2141 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2142 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2143 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2144 sm_ec_generate_new_key(); 2145 } 2146 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2147 continue; 2148 } 2149 } 2150 #endif 2151 2152 switch (sm_connection->sm_engine_state) { 2153 #ifdef ENABLE_LE_PERIPHERAL 2154 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2155 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2156 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2157 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2158 case SM_SC_RECEIVED_LTK_REQUEST: 2159 #endif 2160 #endif 2161 #ifdef ENABLE_LE_CENTRAL 2162 case SM_INITIATOR_PH0_HAS_LTK: 2163 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2164 #endif 2165 // just lock context 2166 break; 2167 default: 2168 done = 0; 2169 break; 2170 } 2171 if (done){ 2172 sm_active_connection_handle = sm_connection->sm_handle; 2173 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); 2174 } 2175 } 2176 } 2177 2178 static void sm_run(void){ 2179 2180 // assert that stack has already bootet 2181 if (hci_get_state() != HCI_STATE_WORKING) return; 2182 2183 // assert that we can send at least commands 2184 if (!hci_can_send_command_packet_now()) return; 2185 2186 // pause until IR/ER are ready 2187 if (sm_persistent_keys_random_active) return; 2188 2189 bool done; 2190 2191 // 2192 // non-connection related behaviour 2193 // 2194 2195 done = sm_run_dpkg(); 2196 if (done) return; 2197 2198 done = sm_run_rau(); 2199 if (done) return; 2200 2201 done = sm_run_csrk(); 2202 if (done) return; 2203 2204 done = sm_run_oob(); 2205 if (done) return; 2206 2207 // assert that we can send at least commands - cmd might have been sent by crypto engine 2208 if (!hci_can_send_command_packet_now()) return; 2209 2210 // handle basic actions that don't requires the full context 2211 done = sm_run_basic(); 2212 if (done) return; 2213 2214 // 2215 // active connection handling 2216 // -- use loop to handle next connection if lock on setup context is released 2217 2218 while (true) { 2219 2220 sm_run_activate_connection(); 2221 2222 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2223 2224 // 2225 // active connection handling 2226 // 2227 2228 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2229 if (!connection) { 2230 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2231 return; 2232 } 2233 2234 // assert that we could send a SM PDU - not needed for all of the following 2235 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2236 log_info("cannot send now, requesting can send now event"); 2237 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2238 return; 2239 } 2240 2241 // send keypress notifications 2242 if (setup->sm_keypress_notification){ 2243 int i; 2244 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2245 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2246 uint8_t action = 0; 2247 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2248 if (flags & (1u<<i)){ 2249 int clear_flag = 1; 2250 switch (i){ 2251 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2252 case SM_KEYPRESS_PASSKEY_CLEARED: 2253 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2254 default: 2255 break; 2256 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2257 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2258 num_actions--; 2259 clear_flag = num_actions == 0u; 2260 break; 2261 } 2262 if (clear_flag){ 2263 flags &= ~(1<<i); 2264 } 2265 action = i; 2266 break; 2267 } 2268 } 2269 setup->sm_keypress_notification = (num_actions << 5) | flags; 2270 2271 // send keypress notification 2272 uint8_t buffer[2]; 2273 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2274 buffer[1] = action; 2275 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2276 2277 // try 2278 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2279 return; 2280 } 2281 2282 int key_distribution_flags; 2283 UNUSED(key_distribution_flags); 2284 int err; 2285 UNUSED(err); 2286 2287 log_info("sm_run: state %u", connection->sm_engine_state); 2288 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2289 log_info("sm_run // cannot send"); 2290 } 2291 switch (connection->sm_engine_state){ 2292 2293 // general 2294 case SM_GENERAL_SEND_PAIRING_FAILED: { 2295 uint8_t buffer[2]; 2296 buffer[0] = SM_CODE_PAIRING_FAILED; 2297 buffer[1] = setup->sm_pairing_failed_reason; 2298 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2299 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2300 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2301 sm_done_for_handle(connection->sm_handle); 2302 break; 2303 } 2304 2305 // secure connections, initiator + responding states 2306 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2307 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2308 if (!sm_cmac_ready()) break; 2309 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2310 sm_sc_calculate_local_confirm(connection); 2311 break; 2312 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2313 if (!sm_cmac_ready()) break; 2314 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2315 sm_sc_calculate_remote_confirm(connection); 2316 break; 2317 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2318 if (!sm_cmac_ready()) break; 2319 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2320 sm_sc_calculate_f6_for_dhkey_check(connection); 2321 break; 2322 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2323 if (!sm_cmac_ready()) break; 2324 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2325 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2326 break; 2327 case SM_SC_W2_CALCULATE_F5_SALT: 2328 if (!sm_cmac_ready()) break; 2329 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2330 f5_calculate_salt(connection); 2331 break; 2332 case SM_SC_W2_CALCULATE_F5_MACKEY: 2333 if (!sm_cmac_ready()) break; 2334 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2335 f5_calculate_mackey(connection); 2336 break; 2337 case SM_SC_W2_CALCULATE_F5_LTK: 2338 if (!sm_cmac_ready()) break; 2339 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2340 f5_calculate_ltk(connection); 2341 break; 2342 case SM_SC_W2_CALCULATE_G2: 2343 if (!sm_cmac_ready()) break; 2344 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2345 g2_calculate(connection); 2346 break; 2347 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2348 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2349 if (!sm_cmac_ready()) break; 2350 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2351 h6_calculate_ilk(connection); 2352 break; 2353 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2354 if (!sm_cmac_ready()) break; 2355 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2356 h6_calculate_br_edr_link_key(connection); 2357 break; 2358 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2359 if (!sm_cmac_ready()) break; 2360 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2361 h7_calculate_ilk(connection); 2362 break; 2363 #endif 2364 #endif 2365 2366 #ifdef ENABLE_LE_CENTRAL 2367 // initiator side 2368 2369 case SM_INITIATOR_PH0_HAS_LTK: { 2370 sm_reset_setup(); 2371 sm_load_security_info(connection); 2372 2373 sm_key_t peer_ltk_flipped; 2374 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2375 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2376 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2377 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2378 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2379 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2380 return; 2381 } 2382 2383 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2384 sm_reset_setup(); 2385 sm_init_setup(connection); 2386 sm_timeout_start(connection); 2387 2388 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2389 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2390 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2391 sm_timeout_reset(connection); 2392 break; 2393 #endif 2394 2395 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2396 2397 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2398 int trigger_user_response = 0; 2399 int trigger_start_calculating_local_confirm = 0; 2400 uint8_t buffer[65]; 2401 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2402 // 2403 reverse_256(&ec_q[0], &buffer[1]); 2404 reverse_256(&ec_q[32], &buffer[33]); 2405 2406 #ifdef ENABLE_TESTING_SUPPORT 2407 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2408 log_info("testing_support: invalidating public key"); 2409 // flip single bit of public key coordinate 2410 buffer[1] ^= 1; 2411 } 2412 #endif 2413 2414 // stk generation method 2415 // passkey entry: notify app to show passkey or to request passkey 2416 switch (setup->sm_stk_generation_method){ 2417 case JUST_WORKS: 2418 case NUMERIC_COMPARISON: 2419 if (IS_RESPONDER(connection->sm_role)){ 2420 // responder 2421 trigger_start_calculating_local_confirm = 1; 2422 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2423 } else { 2424 // initiator 2425 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2426 } 2427 break; 2428 case PK_INIT_INPUT: 2429 case PK_RESP_INPUT: 2430 case PK_BOTH_INPUT: 2431 // use random TK for display 2432 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2433 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2434 setup->sm_passkey_bit = 0; 2435 2436 if (IS_RESPONDER(connection->sm_role)){ 2437 // responder 2438 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2439 } else { 2440 // initiator 2441 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2442 } 2443 trigger_user_response = 1; 2444 break; 2445 case OOB: 2446 if (IS_RESPONDER(connection->sm_role)){ 2447 // responder 2448 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2449 } else { 2450 // initiator 2451 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2452 } 2453 break; 2454 default: 2455 btstack_assert(false); 2456 break; 2457 } 2458 2459 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2460 sm_timeout_reset(connection); 2461 2462 // trigger user response and calc confirm after sending pdu 2463 if (trigger_user_response){ 2464 sm_trigger_user_response(connection); 2465 } 2466 if (trigger_start_calculating_local_confirm){ 2467 sm_sc_start_calculating_local_confirm(connection); 2468 } 2469 break; 2470 } 2471 case SM_SC_SEND_CONFIRMATION: { 2472 uint8_t buffer[17]; 2473 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2474 reverse_128(setup->sm_local_confirm, &buffer[1]); 2475 if (IS_RESPONDER(connection->sm_role)){ 2476 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2477 } else { 2478 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2479 } 2480 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2481 sm_timeout_reset(connection); 2482 break; 2483 } 2484 case SM_SC_SEND_PAIRING_RANDOM: { 2485 uint8_t buffer[17]; 2486 buffer[0] = SM_CODE_PAIRING_RANDOM; 2487 reverse_128(setup->sm_local_nonce, &buffer[1]); 2488 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2489 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2490 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2491 if (IS_RESPONDER(connection->sm_role)){ 2492 // responder 2493 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2494 } else { 2495 // initiator 2496 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2497 } 2498 } else { 2499 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2500 if (IS_RESPONDER(connection->sm_role)){ 2501 // responder 2502 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2503 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2504 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2505 } else { 2506 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2507 sm_sc_prepare_dhkey_check(connection); 2508 } 2509 } else { 2510 // initiator 2511 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2512 } 2513 } 2514 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2515 sm_timeout_reset(connection); 2516 break; 2517 } 2518 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2519 uint8_t buffer[17]; 2520 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2521 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2522 2523 if (IS_RESPONDER(connection->sm_role)){ 2524 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2525 } else { 2526 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2527 } 2528 2529 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2530 sm_timeout_reset(connection); 2531 break; 2532 } 2533 2534 #endif 2535 2536 #ifdef ENABLE_LE_PERIPHERAL 2537 2538 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2539 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2540 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2541 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2542 sm_timeout_start(connection); 2543 break; 2544 } 2545 2546 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2547 case SM_SC_RECEIVED_LTK_REQUEST: 2548 switch (connection->sm_irk_lookup_state){ 2549 case IRK_LOOKUP_SUCCEEDED: 2550 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2551 // start using context by loading security info 2552 sm_reset_setup(); 2553 sm_load_security_info(connection); 2554 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2555 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2556 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2557 sm_trigger_run(); 2558 break; 2559 } 2560 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2561 connection->sm_engine_state = SM_RESPONDER_IDLE; 2562 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2563 return; 2564 default: 2565 // just wait until IRK lookup is completed 2566 break; 2567 } 2568 break; 2569 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2570 2571 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2572 sm_reset_setup(); 2573 sm_init_setup(connection); 2574 // recover pairing request 2575 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2576 err = sm_stk_generation_init(connection); 2577 2578 #ifdef ENABLE_TESTING_SUPPORT 2579 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2580 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2581 err = test_pairing_failure; 2582 } 2583 #endif 2584 if (err){ 2585 setup->sm_pairing_failed_reason = err; 2586 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2587 sm_trigger_run(); 2588 break; 2589 } 2590 2591 sm_timeout_start(connection); 2592 2593 // generate random number first, if we need to show passkey, otherwise send response 2594 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2595 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2596 break; 2597 } 2598 2599 /* fall through */ 2600 2601 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2602 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2603 2604 // start with initiator key dist flags 2605 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2606 2607 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2608 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2609 if (setup->sm_use_secure_connections){ 2610 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2611 } 2612 #endif 2613 // setup in response 2614 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); 2615 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); 2616 2617 // update key distribution after ENC was dropped 2618 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2619 2620 if (setup->sm_use_secure_connections){ 2621 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2622 } else { 2623 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2624 } 2625 2626 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2627 sm_timeout_reset(connection); 2628 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2629 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2630 sm_trigger_user_response(connection); 2631 } 2632 return; 2633 #endif 2634 2635 case SM_PH2_SEND_PAIRING_RANDOM: { 2636 uint8_t buffer[17]; 2637 buffer[0] = SM_CODE_PAIRING_RANDOM; 2638 reverse_128(setup->sm_local_random, &buffer[1]); 2639 if (IS_RESPONDER(connection->sm_role)){ 2640 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2641 } else { 2642 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2643 } 2644 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2645 sm_timeout_reset(connection); 2646 break; 2647 } 2648 2649 case SM_PH2_C1_GET_ENC_A: 2650 // already busy? 2651 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2652 // calculate confirm using aes128 engine - step 1 2653 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); 2654 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2655 sm_aes128_state = SM_AES128_ACTIVE; 2656 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, (void *)(uintptr_t) connection->sm_handle); 2657 break; 2658 2659 case SM_PH2_C1_GET_ENC_C: 2660 // already busy? 2661 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2662 // calculate m_confirm using aes128 engine - step 1 2663 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); 2664 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2665 sm_aes128_state = SM_AES128_ACTIVE; 2666 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, (void *)(uintptr_t) connection->sm_handle); 2667 break; 2668 2669 case SM_PH2_CALC_STK: 2670 // already busy? 2671 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2672 // calculate STK 2673 if (IS_RESPONDER(connection->sm_role)){ 2674 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2675 } else { 2676 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2677 } 2678 connection->sm_engine_state = SM_PH2_W4_STK; 2679 sm_aes128_state = SM_AES128_ACTIVE; 2680 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2681 break; 2682 2683 case SM_PH3_Y_GET_ENC: 2684 // already busy? 2685 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2686 // PH3B2 - calculate Y from - enc 2687 2688 // dm helper (was sm_dm_r_prime) 2689 // r' = padding || r 2690 // r - 64 bit value 2691 memset(&sm_aes128_plaintext[0], 0, 8); 2692 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2693 2694 // Y = dm(DHK, Rand) 2695 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2696 sm_aes128_state = SM_AES128_ACTIVE; 2697 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, (void *)(uintptr_t) connection->sm_handle); 2698 break; 2699 2700 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2701 uint8_t buffer[17]; 2702 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2703 reverse_128(setup->sm_local_confirm, &buffer[1]); 2704 if (IS_RESPONDER(connection->sm_role)){ 2705 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2706 } else { 2707 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2708 } 2709 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2710 sm_timeout_reset(connection); 2711 return; 2712 } 2713 #ifdef ENABLE_LE_PERIPHERAL 2714 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2715 sm_key_t stk_flipped; 2716 reverse_128(setup->sm_ltk, stk_flipped); 2717 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2718 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2719 return; 2720 } 2721 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2722 sm_key_t ltk_flipped; 2723 reverse_128(setup->sm_ltk, ltk_flipped); 2724 connection->sm_engine_state = SM_RESPONDER_IDLE; 2725 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2726 sm_done_for_handle(connection->sm_handle); 2727 return; 2728 } 2729 2730 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2731 // already busy? 2732 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2733 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2734 2735 sm_reset_setup(); 2736 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2737 2738 // dm helper (was sm_dm_r_prime) 2739 // r' = padding || r 2740 // r - 64 bit value 2741 memset(&sm_aes128_plaintext[0], 0, 8); 2742 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2743 2744 // Y = dm(DHK, Rand) 2745 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2746 sm_aes128_state = SM_AES128_ACTIVE; 2747 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, (void *)(uintptr_t) connection->sm_handle); 2748 return; 2749 #endif 2750 #ifdef ENABLE_LE_CENTRAL 2751 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2752 sm_key_t stk_flipped; 2753 reverse_128(setup->sm_ltk, stk_flipped); 2754 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2755 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2756 return; 2757 } 2758 #endif 2759 2760 case SM_PH3_DISTRIBUTE_KEYS: 2761 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2762 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2763 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2764 uint8_t buffer[17]; 2765 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2766 reverse_128(setup->sm_ltk, &buffer[1]); 2767 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2768 sm_timeout_reset(connection); 2769 return; 2770 } 2771 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2772 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2773 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2774 uint8_t buffer[11]; 2775 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2776 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2777 reverse_64(setup->sm_local_rand, &buffer[3]); 2778 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2779 sm_timeout_reset(connection); 2780 return; 2781 } 2782 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2783 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2784 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2785 uint8_t buffer[17]; 2786 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2787 reverse_128(sm_persistent_irk, &buffer[1]); 2788 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2789 sm_timeout_reset(connection); 2790 return; 2791 } 2792 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2793 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2794 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2795 bd_addr_t local_address; 2796 uint8_t buffer[8]; 2797 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2798 switch (gap_random_address_get_mode()){ 2799 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2800 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2801 // public or static random 2802 gap_le_get_own_address(&buffer[1], local_address); 2803 break; 2804 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2805 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2806 // fallback to public 2807 gap_local_bd_addr(local_address); 2808 buffer[1] = 0; 2809 break; 2810 default: 2811 btstack_assert(false); 2812 break; 2813 } 2814 reverse_bd_addr(local_address, &buffer[2]); 2815 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2816 sm_timeout_reset(connection); 2817 return; 2818 } 2819 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2820 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2821 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2822 2823 #ifdef ENABLE_LE_SIGNED_WRITE 2824 // hack to reproduce test runs 2825 if (test_use_fixed_local_csrk){ 2826 memset(setup->sm_local_csrk, 0xcc, 16); 2827 } 2828 2829 // store local CSRK 2830 if (setup->sm_le_device_index >= 0){ 2831 log_info("sm: store local CSRK"); 2832 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2833 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2834 } 2835 #endif 2836 2837 uint8_t buffer[17]; 2838 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2839 reverse_128(setup->sm_local_csrk, &buffer[1]); 2840 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2841 sm_timeout_reset(connection); 2842 return; 2843 } 2844 2845 // keys are sent 2846 if (IS_RESPONDER(connection->sm_role)){ 2847 // slave -> receive master keys if any 2848 if (sm_key_distribution_all_received(connection)){ 2849 sm_key_distribution_handle_all_received(connection); 2850 connection->sm_engine_state = SM_RESPONDER_IDLE; 2851 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2852 sm_done_for_handle(connection->sm_handle); 2853 } else { 2854 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2855 } 2856 } else { 2857 sm_master_pairing_success(connection); 2858 } 2859 break; 2860 2861 default: 2862 break; 2863 } 2864 2865 // check again if active connection was released 2866 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2867 } 2868 } 2869 2870 // sm_aes128_state stays active 2871 static void sm_handle_encryption_result_enc_a(void *arg){ 2872 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2873 sm_aes128_state = SM_AES128_IDLE; 2874 2875 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2876 if (connection == NULL) return; 2877 2878 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2879 sm_aes128_state = SM_AES128_ACTIVE; 2880 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, (void *)(uintptr_t) connection->sm_handle); 2881 } 2882 2883 static void sm_handle_encryption_result_enc_b(void *arg){ 2884 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2885 sm_aes128_state = SM_AES128_IDLE; 2886 2887 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2888 if (connection == NULL) return; 2889 2890 log_info_key("c1!", setup->sm_local_confirm); 2891 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2892 sm_trigger_run(); 2893 } 2894 2895 // sm_aes128_state stays active 2896 static void sm_handle_encryption_result_enc_c(void *arg){ 2897 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2898 sm_aes128_state = SM_AES128_IDLE; 2899 2900 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2901 if (connection == NULL) return; 2902 2903 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2904 sm_aes128_state = SM_AES128_ACTIVE; 2905 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, (void *)(uintptr_t) connection->sm_handle); 2906 } 2907 2908 static void sm_handle_encryption_result_enc_d(void * arg){ 2909 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2910 sm_aes128_state = SM_AES128_IDLE; 2911 2912 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2913 if (connection == NULL) return; 2914 2915 log_info_key("c1!", sm_aes128_ciphertext); 2916 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2917 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2918 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2919 sm_trigger_run(); 2920 return; 2921 } 2922 if (IS_RESPONDER(connection->sm_role)){ 2923 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2924 sm_trigger_run(); 2925 } else { 2926 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2927 sm_aes128_state = SM_AES128_ACTIVE; 2928 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2929 } 2930 } 2931 2932 static void sm_handle_encryption_result_enc_stk(void *arg){ 2933 sm_aes128_state = SM_AES128_IDLE; 2934 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2935 2936 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2937 if (connection == NULL) return; 2938 2939 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2940 log_info_key("stk", setup->sm_ltk); 2941 if (IS_RESPONDER(connection->sm_role)){ 2942 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2943 } else { 2944 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2945 } 2946 sm_trigger_run(); 2947 } 2948 2949 // sm_aes128_state stays active 2950 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2951 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2952 sm_aes128_state = SM_AES128_IDLE; 2953 2954 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2955 if (connection == NULL) return; 2956 2957 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2958 log_info_hex16("y", setup->sm_local_y); 2959 // PH3B3 - calculate EDIV 2960 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2961 log_info_hex16("ediv", setup->sm_local_ediv); 2962 // PH3B4 - calculate LTK - enc 2963 // LTK = d1(ER, DIV, 0)) 2964 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2965 sm_aes128_state = SM_AES128_ACTIVE; 2966 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); 2967 } 2968 2969 #ifdef ENABLE_LE_PERIPHERAL 2970 // sm_aes128_state stays active 2971 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2972 sm_aes128_state = SM_AES128_IDLE; 2973 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2974 2975 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2976 if (connection == NULL) return; 2977 2978 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2979 log_info_hex16("y", setup->sm_local_y); 2980 2981 // PH3B3 - calculate DIV 2982 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2983 log_info_hex16("ediv", setup->sm_local_ediv); 2984 // PH3B4 - calculate LTK - enc 2985 // LTK = d1(ER, DIV, 0)) 2986 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2987 sm_aes128_state = SM_AES128_ACTIVE; 2988 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, (void *)(uintptr_t) connection->sm_handle); 2989 } 2990 #endif 2991 2992 // sm_aes128_state stays active 2993 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2994 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2995 sm_aes128_state = SM_AES128_IDLE; 2996 2997 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2998 if (connection == NULL) return; 2999 3000 log_info_key("ltk", setup->sm_ltk); 3001 // calc CSRK next 3002 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3003 sm_aes128_state = SM_AES128_ACTIVE; 3004 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); 3005 } 3006 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3007 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3008 // requirements to derive link key from LE: 3009 // - use secure connections 3010 if (setup->sm_use_secure_connections == 0) return false; 3011 // - bonding needs to be enabled: 3012 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_BONDING ) != 0u; 3013 if (!bonding_enabled) return false; 3014 // - need identity address 3015 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3016 if (!have_identity_address_info) return false; 3017 // - there is no stored BR/EDR link key or the derived key has at least the same level of authentication (bail if stored key has higher authentication) 3018 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3019 // If SC is authenticated, we consider it safe to overwrite a stored key. 3020 // If stored link key is not authenticated, it could already be compromised by a MITM attack. Allowing overwrite by unauthenticated derived key does not make it worse. 3021 uint8_t link_key[16]; 3022 link_key_type_t link_key_type; 3023 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3024 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3025 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3026 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3027 return false; 3028 } 3029 // get started (all of the above are true) 3030 return true; 3031 #else 3032 UNUSED(sm_connection); 3033 return false; 3034 #endif 3035 } 3036 3037 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3038 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3039 sm_aes128_state = SM_AES128_IDLE; 3040 3041 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3042 if (connection == NULL) return; 3043 3044 sm_aes128_state = SM_AES128_IDLE; 3045 log_info_key("csrk", setup->sm_local_csrk); 3046 if (setup->sm_key_distribution_send_set){ 3047 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3048 } else { 3049 // no keys to send, just continue 3050 if (IS_RESPONDER(connection->sm_role)){ 3051 // slave -> receive master keys 3052 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3053 } else { 3054 if (sm_ctkd_from_le(connection)){ 3055 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 3056 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3057 } else { 3058 sm_master_pairing_success(connection); 3059 } 3060 } 3061 } 3062 sm_trigger_run(); 3063 } 3064 3065 #ifdef ENABLE_LE_PERIPHERAL 3066 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3067 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3068 sm_aes128_state = SM_AES128_IDLE; 3069 3070 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3071 if (connection == NULL) return; 3072 3073 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3074 log_info_key("ltk", setup->sm_ltk); 3075 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3076 sm_trigger_run(); 3077 } 3078 #endif 3079 3080 static void sm_handle_encryption_result_address_resolution(void *arg){ 3081 UNUSED(arg); 3082 sm_aes128_state = SM_AES128_IDLE; 3083 3084 sm_address_resolution_ah_calculation_active = 0; 3085 // compare calulated address against connecting device 3086 uint8_t * hash = &sm_aes128_ciphertext[13]; 3087 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3088 log_info("LE Device Lookup: matched resolvable private address"); 3089 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3090 sm_trigger_run(); 3091 return; 3092 } 3093 // no match, try next 3094 sm_address_resolution_test++; 3095 sm_trigger_run(); 3096 } 3097 3098 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3099 UNUSED(arg); 3100 sm_aes128_state = SM_AES128_IDLE; 3101 3102 log_info_key("irk", sm_persistent_irk); 3103 dkg_state = DKG_CALC_DHK; 3104 sm_trigger_run(); 3105 } 3106 3107 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3108 UNUSED(arg); 3109 sm_aes128_state = SM_AES128_IDLE; 3110 3111 log_info_key("dhk", sm_persistent_dhk); 3112 dkg_state = DKG_READY; 3113 sm_trigger_run(); 3114 } 3115 3116 static void sm_handle_encryption_result_rau(void *arg){ 3117 UNUSED(arg); 3118 sm_aes128_state = SM_AES128_IDLE; 3119 3120 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3121 rau_state = RAU_SET_ADDRESS; 3122 sm_trigger_run(); 3123 } 3124 3125 static void sm_handle_random_result_rau(void * arg){ 3126 UNUSED(arg); 3127 // non-resolvable vs. resolvable 3128 switch (gap_random_adress_type){ 3129 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3130 // resolvable: use random as prand and calc address hash 3131 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3132 sm_random_address[0u] &= 0x3fu; 3133 sm_random_address[0u] |= 0x40u; 3134 rau_state = RAU_GET_ENC; 3135 break; 3136 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3137 default: 3138 // "The two most significant bits of the address shall be equal to ‘0’"" 3139 sm_random_address[0u] &= 0x3fu; 3140 rau_state = RAU_SET_ADDRESS; 3141 break; 3142 } 3143 sm_trigger_run(); 3144 } 3145 3146 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3147 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3148 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3149 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3150 if (connection == NULL) return; 3151 3152 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3153 sm_trigger_run(); 3154 } 3155 3156 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3157 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3158 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3159 if (connection == NULL) return; 3160 3161 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3162 sm_trigger_run(); 3163 } 3164 #endif 3165 3166 static void sm_handle_random_result_ph2_random(void * arg){ 3167 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3168 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3169 if (connection == NULL) return; 3170 3171 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3172 sm_trigger_run(); 3173 } 3174 3175 static void sm_handle_random_result_ph2_tk(void * arg){ 3176 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3177 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3178 if (connection == NULL) return; 3179 3180 sm_reset_tk(); 3181 uint32_t tk; 3182 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3183 // map random to 0-999999 without speding much cycles on a modulus operation 3184 tk = little_endian_read_32(sm_random_data,0); 3185 tk = tk & 0xfffff; // 1048575 3186 if (tk >= 999999u){ 3187 tk = tk - 999999u; 3188 } 3189 } else { 3190 // override with pre-defined passkey 3191 tk = sm_fixed_passkey_in_display_role; 3192 } 3193 big_endian_store_32(setup->sm_tk, 12, tk); 3194 if (IS_RESPONDER(connection->sm_role)){ 3195 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3196 } else { 3197 if (setup->sm_use_secure_connections){ 3198 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3199 } else { 3200 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3201 sm_trigger_user_response(connection); 3202 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3203 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3204 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) connection->sm_handle); 3205 } 3206 } 3207 } 3208 sm_trigger_run(); 3209 } 3210 3211 static void sm_handle_random_result_ph3_div(void * arg){ 3212 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3213 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3214 if (connection == NULL) return; 3215 3216 // use 16 bit from random value as div 3217 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3218 log_info_hex16("div", setup->sm_local_div); 3219 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3220 sm_trigger_run(); 3221 } 3222 3223 static void sm_handle_random_result_ph3_random(void * arg){ 3224 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3225 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3226 if (connection == NULL) return; 3227 3228 reverse_64(sm_random_data, setup->sm_local_rand); 3229 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3230 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3231 // no db for authenticated flag hack: store flag in bit 4 of LSB 3232 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3233 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3234 } 3235 static void sm_validate_er_ir(void){ 3236 // warn about default ER/IR 3237 int warning = 0; 3238 if (sm_ir_is_default()){ 3239 warning = 1; 3240 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3241 } 3242 if (sm_er_is_default()){ 3243 warning = 1; 3244 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3245 } 3246 if (warning) { 3247 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3248 } 3249 } 3250 3251 static void sm_handle_random_result_ir(void *arg){ 3252 sm_persistent_keys_random_active = 0; 3253 if (arg){ 3254 // key generated, store in tlv 3255 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3256 log_info("Generated IR key. Store in TLV status: %d", status); 3257 UNUSED(status); 3258 } 3259 log_info_key("IR", sm_persistent_ir); 3260 dkg_state = DKG_CALC_IRK; 3261 3262 if (test_use_fixed_local_irk){ 3263 log_info_key("IRK", sm_persistent_irk); 3264 dkg_state = DKG_CALC_DHK; 3265 } 3266 3267 sm_trigger_run(); 3268 } 3269 3270 static void sm_handle_random_result_er(void *arg){ 3271 sm_persistent_keys_random_active = 0; 3272 if (arg){ 3273 // key generated, store in tlv 3274 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3275 log_info("Generated ER key. Store in TLV status: %d", status); 3276 UNUSED(status); 3277 } 3278 log_info_key("ER", sm_persistent_er); 3279 3280 // try load ir 3281 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3282 if (key_size == 16){ 3283 // ok, let's continue 3284 log_info("IR from TLV"); 3285 sm_handle_random_result_ir( NULL ); 3286 } else { 3287 // invalid, generate new random one 3288 sm_persistent_keys_random_active = 1; 3289 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3290 } 3291 } 3292 3293 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3294 3295 UNUSED(channel); // ok: there is no channel 3296 UNUSED(size); // ok: fixed format HCI events 3297 3298 sm_connection_t * sm_conn; 3299 hci_con_handle_t con_handle; 3300 3301 switch (packet_type) { 3302 3303 case HCI_EVENT_PACKET: 3304 switch (hci_event_packet_get_type(packet)) { 3305 3306 case BTSTACK_EVENT_STATE: 3307 // bt stack activated, get started 3308 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3309 log_info("HCI Working!"); 3310 3311 // setup IR/ER with TLV 3312 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3313 if (sm_tlv_impl){ 3314 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3315 if (key_size == 16){ 3316 // ok, let's continue 3317 log_info("ER from TLV"); 3318 sm_handle_random_result_er( NULL ); 3319 } else { 3320 // invalid, generate random one 3321 sm_persistent_keys_random_active = 1; 3322 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3323 } 3324 } else { 3325 sm_validate_er_ir(); 3326 dkg_state = DKG_CALC_IRK; 3327 3328 if (test_use_fixed_local_irk){ 3329 log_info_key("IRK", sm_persistent_irk); 3330 dkg_state = DKG_CALC_DHK; 3331 } 3332 } 3333 3334 // restart random address updates after power cycle 3335 gap_random_address_set_mode(gap_random_adress_type); 3336 } 3337 break; 3338 3339 case HCI_EVENT_LE_META: 3340 switch (packet[2]) { 3341 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3342 3343 log_info("sm: connected"); 3344 3345 if (packet[3]) return; // connection failed 3346 3347 con_handle = little_endian_read_16(packet, 4); 3348 sm_conn = sm_get_connection_for_handle(con_handle); 3349 if (!sm_conn) break; 3350 3351 sm_conn->sm_handle = con_handle; 3352 sm_conn->sm_role = packet[6]; 3353 sm_conn->sm_peer_addr_type = packet[7]; 3354 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3355 3356 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3357 3358 // reset security properties 3359 sm_conn->sm_connection_encrypted = 0; 3360 sm_conn->sm_connection_authenticated = 0; 3361 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3362 sm_conn->sm_le_db_index = -1; 3363 3364 // prepare CSRK lookup (does not involve setup) 3365 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3366 3367 // just connected -> everything else happens in sm_run() 3368 if (IS_RESPONDER(sm_conn->sm_role)){ 3369 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3370 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3371 if (sm_slave_request_security) { 3372 // request security if requested by app 3373 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3374 } else { 3375 // otherwise, wait for pairing request 3376 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3377 } 3378 } 3379 break; 3380 } else { 3381 // master 3382 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3383 } 3384 break; 3385 3386 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3387 con_handle = little_endian_read_16(packet, 3); 3388 sm_conn = sm_get_connection_for_handle(con_handle); 3389 if (!sm_conn) break; 3390 3391 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3392 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3393 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3394 break; 3395 } 3396 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3397 // PH2 SEND LTK as we need to exchange keys in PH3 3398 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3399 break; 3400 } 3401 3402 // store rand and ediv 3403 reverse_64(&packet[5], sm_conn->sm_local_rand); 3404 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3405 3406 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3407 // potentially stored LTK is from the master 3408 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3409 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3410 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3411 break; 3412 } 3413 // additionally check if remote is in LE Device DB if requested 3414 switch(sm_conn->sm_irk_lookup_state){ 3415 case IRK_LOOKUP_FAILED: 3416 log_info("LTK Request: device not in device db"); 3417 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3418 break; 3419 case IRK_LOOKUP_SUCCEEDED: 3420 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3421 break; 3422 default: 3423 // wait for irk look doen 3424 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3425 break; 3426 } 3427 break; 3428 } 3429 3430 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3431 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3432 #else 3433 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3434 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3435 #endif 3436 break; 3437 3438 default: 3439 break; 3440 } 3441 break; 3442 3443 case HCI_EVENT_ENCRYPTION_CHANGE: 3444 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3445 sm_conn = sm_get_connection_for_handle(con_handle); 3446 if (!sm_conn) break; 3447 3448 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3449 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3450 sm_conn->sm_actual_encryption_key_size); 3451 log_info("event handler, state %u", sm_conn->sm_engine_state); 3452 3453 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3454 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3455 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3456 // block connection if encryption fails 3457 if (sm_conn->sm_connection_encrypted == 0){ 3458 // set state to 'TIMEOUT' to prevent further interaction with this 3459 // also, gap_reconnect_security_setup_active will return true 3460 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 3461 } 3462 // notify client, if pairing was requested before 3463 if (sm_conn->sm_pairing_requested){ 3464 sm_conn->sm_pairing_requested = 0; 3465 if (sm_conn->sm_connection_encrypted){ 3466 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3467 } else { 3468 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3469 } 3470 } 3471 sm_done_for_handle(sm_conn->sm_handle); 3472 break; 3473 } 3474 3475 if (!sm_conn->sm_connection_encrypted) break; 3476 3477 // continue pairing 3478 switch (sm_conn->sm_engine_state){ 3479 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3480 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3481 sm_done_for_handle(sm_conn->sm_handle); 3482 break; 3483 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3484 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3485 if (IS_RESPONDER(sm_conn->sm_role)){ 3486 // slave 3487 if (setup->sm_use_secure_connections){ 3488 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3489 } else { 3490 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3491 } 3492 } else { 3493 // master 3494 if (sm_key_distribution_all_received(sm_conn)){ 3495 // skip receiving keys as there are none 3496 sm_key_distribution_handle_all_received(sm_conn); 3497 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3498 } else { 3499 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3500 } 3501 } 3502 break; 3503 default: 3504 break; 3505 } 3506 break; 3507 3508 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3509 con_handle = little_endian_read_16(packet, 3); 3510 sm_conn = sm_get_connection_for_handle(con_handle); 3511 if (!sm_conn) break; 3512 3513 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3514 log_info("event handler, state %u", sm_conn->sm_engine_state); 3515 // continue if part of initial pairing 3516 switch (sm_conn->sm_engine_state){ 3517 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3518 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3519 sm_done_for_handle(sm_conn->sm_handle); 3520 break; 3521 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3522 if (IS_RESPONDER(sm_conn->sm_role)){ 3523 // slave 3524 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3525 } else { 3526 // master 3527 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3528 } 3529 break; 3530 default: 3531 break; 3532 } 3533 break; 3534 3535 3536 case HCI_EVENT_DISCONNECTION_COMPLETE: 3537 con_handle = little_endian_read_16(packet, 3); 3538 sm_done_for_handle(con_handle); 3539 sm_conn = sm_get_connection_for_handle(con_handle); 3540 if (!sm_conn) break; 3541 3542 // delete stored bonding on disconnect with authentication failure in ph0 3543 if ((sm_conn->sm_role == 0u) 3544 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3545 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3546 le_device_db_remove(sm_conn->sm_le_db_index); 3547 } 3548 3549 // pairing failed, if it was ongoing 3550 switch (sm_conn->sm_engine_state){ 3551 case SM_GENERAL_IDLE: 3552 case SM_INITIATOR_CONNECTED: 3553 case SM_RESPONDER_IDLE: 3554 break; 3555 default: 3556 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3557 break; 3558 } 3559 3560 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3561 sm_conn->sm_handle = 0; 3562 break; 3563 3564 case HCI_EVENT_COMMAND_COMPLETE: 3565 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3566 // set local addr for le device db 3567 bd_addr_t addr; 3568 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3569 le_device_db_set_local_bd_addr(addr); 3570 } 3571 break; 3572 default: 3573 break; 3574 } 3575 break; 3576 default: 3577 break; 3578 } 3579 3580 sm_run(); 3581 } 3582 3583 static inline int sm_calc_actual_encryption_key_size(int other){ 3584 if (other < sm_min_encryption_key_size) return 0; 3585 if (other < sm_max_encryption_key_size) return other; 3586 return sm_max_encryption_key_size; 3587 } 3588 3589 3590 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3591 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3592 switch (method){ 3593 case JUST_WORKS: 3594 case NUMERIC_COMPARISON: 3595 return 1; 3596 default: 3597 return 0; 3598 } 3599 } 3600 // responder 3601 3602 static int sm_passkey_used(stk_generation_method_t method){ 3603 switch (method){ 3604 case PK_RESP_INPUT: 3605 return 1; 3606 default: 3607 return 0; 3608 } 3609 } 3610 3611 static int sm_passkey_entry(stk_generation_method_t method){ 3612 switch (method){ 3613 case PK_RESP_INPUT: 3614 case PK_INIT_INPUT: 3615 case PK_BOTH_INPUT: 3616 return 1; 3617 default: 3618 return 0; 3619 } 3620 } 3621 3622 #endif 3623 3624 /** 3625 * @return ok 3626 */ 3627 static int sm_validate_stk_generation_method(void){ 3628 // check if STK generation method is acceptable by client 3629 switch (setup->sm_stk_generation_method){ 3630 case JUST_WORKS: 3631 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3632 case PK_RESP_INPUT: 3633 case PK_INIT_INPUT: 3634 case PK_BOTH_INPUT: 3635 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3636 case OOB: 3637 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3638 case NUMERIC_COMPARISON: 3639 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3640 default: 3641 return 0; 3642 } 3643 } 3644 3645 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3646 3647 // size of complete sm_pdu used to validate input 3648 static const uint8_t sm_pdu_size[] = { 3649 0, // 0x00 invalid opcode 3650 7, // 0x01 pairing request 3651 7, // 0x02 pairing response 3652 17, // 0x03 pairing confirm 3653 17, // 0x04 pairing random 3654 2, // 0x05 pairing failed 3655 17, // 0x06 encryption information 3656 11, // 0x07 master identification 3657 17, // 0x08 identification information 3658 8, // 0x09 identify address information 3659 17, // 0x0a signing information 3660 2, // 0x0b security request 3661 65, // 0x0c pairing public key 3662 17, // 0x0d pairing dhk check 3663 2, // 0x0e keypress notification 3664 }; 3665 3666 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3667 sm_run(); 3668 } 3669 3670 if (packet_type != SM_DATA_PACKET) return; 3671 if (size == 0u) return; 3672 3673 uint8_t sm_pdu_code = packet[0]; 3674 3675 // validate pdu size 3676 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3677 if (sm_pdu_size[sm_pdu_code] != size) return; 3678 3679 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3680 if (!sm_conn) return; 3681 3682 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3683 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3684 sm_done_for_handle(con_handle); 3685 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3686 return; 3687 } 3688 3689 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3690 3691 int err; 3692 UNUSED(err); 3693 3694 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3695 uint8_t buffer[5]; 3696 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3697 buffer[1] = 3; 3698 little_endian_store_16(buffer, 2, con_handle); 3699 buffer[4] = packet[1]; 3700 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3701 return; 3702 } 3703 3704 switch (sm_conn->sm_engine_state){ 3705 3706 // a sm timeout requires a new physical connection 3707 case SM_GENERAL_TIMEOUT: 3708 return; 3709 3710 #ifdef ENABLE_LE_CENTRAL 3711 3712 // Initiator 3713 case SM_INITIATOR_CONNECTED: 3714 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3715 sm_pdu_received_in_wrong_state(sm_conn); 3716 break; 3717 } 3718 3719 // IRK complete? 3720 int have_ltk; 3721 uint8_t ltk[16]; 3722 switch (sm_conn->sm_irk_lookup_state){ 3723 case IRK_LOOKUP_FAILED: 3724 // start pairing 3725 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3726 break; 3727 case IRK_LOOKUP_SUCCEEDED: 3728 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3729 have_ltk = !sm_is_null_key(ltk); 3730 log_info("central: security request - have_ltk %u", have_ltk); 3731 if (have_ltk){ 3732 // start re-encrypt 3733 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3734 } else { 3735 // start pairing 3736 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3737 } 3738 break; 3739 default: 3740 // otherwise, store security request 3741 sm_conn->sm_security_request_received = 1; 3742 break; 3743 } 3744 break; 3745 3746 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3747 // Core 5, Vol 3, Part H, 2.4.6: 3748 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3749 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3750 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3751 log_info("Ignoring Security Request"); 3752 break; 3753 } 3754 3755 // all other pdus are incorrect 3756 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3757 sm_pdu_received_in_wrong_state(sm_conn); 3758 break; 3759 } 3760 3761 // store pairing request 3762 (void)memcpy(&setup->sm_s_pres, packet, 3763 sizeof(sm_pairing_packet_t)); 3764 err = sm_stk_generation_init(sm_conn); 3765 3766 #ifdef ENABLE_TESTING_SUPPORT 3767 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3768 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3769 err = test_pairing_failure; 3770 } 3771 #endif 3772 3773 if (err){ 3774 setup->sm_pairing_failed_reason = err; 3775 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3776 break; 3777 } 3778 3779 // generate random number first, if we need to show passkey 3780 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3781 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_conn->sm_handle); 3782 break; 3783 } 3784 3785 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3786 if (setup->sm_use_secure_connections){ 3787 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3788 if (setup->sm_stk_generation_method == JUST_WORKS){ 3789 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3790 sm_trigger_user_response(sm_conn); 3791 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3792 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3793 } 3794 } else { 3795 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3796 } 3797 break; 3798 } 3799 #endif 3800 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3801 sm_trigger_user_response(sm_conn); 3802 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3803 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3804 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3805 } 3806 break; 3807 3808 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3809 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3810 sm_pdu_received_in_wrong_state(sm_conn); 3811 break; 3812 } 3813 3814 // store s_confirm 3815 reverse_128(&packet[1], setup->sm_peer_confirm); 3816 3817 #ifdef ENABLE_TESTING_SUPPORT 3818 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3819 log_info("testing_support: reset confirm value"); 3820 memset(setup->sm_peer_confirm, 0, 16); 3821 } 3822 #endif 3823 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3824 break; 3825 3826 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3827 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3828 sm_pdu_received_in_wrong_state(sm_conn); 3829 break;; 3830 } 3831 3832 // received random value 3833 reverse_128(&packet[1], setup->sm_peer_random); 3834 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3835 break; 3836 #endif 3837 3838 #ifdef ENABLE_LE_PERIPHERAL 3839 // Responder 3840 case SM_RESPONDER_IDLE: 3841 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3842 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3843 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3844 sm_pdu_received_in_wrong_state(sm_conn); 3845 break;; 3846 } 3847 3848 // store pairing request 3849 (void)memcpy(&sm_conn->sm_m_preq, packet, 3850 sizeof(sm_pairing_packet_t)); 3851 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3852 break; 3853 #endif 3854 3855 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3856 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3857 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3858 sm_pdu_received_in_wrong_state(sm_conn); 3859 break; 3860 } 3861 3862 // store public key for DH Key calculation 3863 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3864 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3865 3866 // validate public key 3867 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3868 if (err){ 3869 log_error("sm: peer public key invalid %x", err); 3870 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3871 break; 3872 } 3873 3874 // start calculating dhkey 3875 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, (void*)(uintptr_t) sm_conn->sm_handle); 3876 3877 3878 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3879 if (IS_RESPONDER(sm_conn->sm_role)){ 3880 // responder 3881 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3882 } else { 3883 // initiator 3884 // stk generation method 3885 // passkey entry: notify app to show passkey or to request passkey 3886 switch (setup->sm_stk_generation_method){ 3887 case JUST_WORKS: 3888 case NUMERIC_COMPARISON: 3889 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3890 break; 3891 case PK_RESP_INPUT: 3892 sm_sc_start_calculating_local_confirm(sm_conn); 3893 break; 3894 case PK_INIT_INPUT: 3895 case PK_BOTH_INPUT: 3896 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3897 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3898 break; 3899 } 3900 sm_sc_start_calculating_local_confirm(sm_conn); 3901 break; 3902 case OOB: 3903 // generate Nx 3904 log_info("Generate Na"); 3905 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3906 break; 3907 default: 3908 btstack_assert(false); 3909 break; 3910 } 3911 } 3912 break; 3913 3914 case SM_SC_W4_CONFIRMATION: 3915 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3916 sm_pdu_received_in_wrong_state(sm_conn); 3917 break; 3918 } 3919 // received confirm value 3920 reverse_128(&packet[1], setup->sm_peer_confirm); 3921 3922 #ifdef ENABLE_TESTING_SUPPORT 3923 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3924 log_info("testing_support: reset confirm value"); 3925 memset(setup->sm_peer_confirm, 0, 16); 3926 } 3927 #endif 3928 if (IS_RESPONDER(sm_conn->sm_role)){ 3929 // responder 3930 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3931 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3932 // still waiting for passkey 3933 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3934 break; 3935 } 3936 } 3937 sm_sc_start_calculating_local_confirm(sm_conn); 3938 } else { 3939 // initiator 3940 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3941 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3942 } else { 3943 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3944 } 3945 } 3946 break; 3947 3948 case SM_SC_W4_PAIRING_RANDOM: 3949 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3950 sm_pdu_received_in_wrong_state(sm_conn); 3951 break; 3952 } 3953 3954 // received random value 3955 reverse_128(&packet[1], setup->sm_peer_nonce); 3956 3957 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3958 // only check for JUST WORK/NC in initiator role OR passkey entry 3959 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 3960 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 3961 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 3962 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3963 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 3964 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3965 break; 3966 } 3967 3968 // OOB 3969 if (setup->sm_stk_generation_method == OOB){ 3970 3971 // setup local random, set to zero if remote did not receive our data 3972 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3973 if (IS_RESPONDER(sm_conn->sm_role)){ 3974 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 3975 log_info("Reset rb as A does not have OOB data"); 3976 memset(setup->sm_rb, 0, 16); 3977 } else { 3978 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3979 log_info("Use stored rb"); 3980 log_info_hexdump(setup->sm_rb, 16); 3981 } 3982 } else { 3983 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 3984 log_info("Reset ra as B does not have OOB data"); 3985 memset(setup->sm_ra, 0, 16); 3986 } else { 3987 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3988 log_info("Use stored ra"); 3989 log_info_hexdump(setup->sm_ra, 16); 3990 } 3991 } 3992 3993 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3994 if (setup->sm_have_oob_data){ 3995 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3996 break; 3997 } 3998 } 3999 4000 // TODO: we only get here for Responder role with JW/NC 4001 sm_sc_state_after_receiving_random(sm_conn); 4002 break; 4003 4004 case SM_SC_W2_CALCULATE_G2: 4005 case SM_SC_W4_CALCULATE_G2: 4006 case SM_SC_W4_CALCULATE_DHKEY: 4007 case SM_SC_W2_CALCULATE_F5_SALT: 4008 case SM_SC_W4_CALCULATE_F5_SALT: 4009 case SM_SC_W2_CALCULATE_F5_MACKEY: 4010 case SM_SC_W4_CALCULATE_F5_MACKEY: 4011 case SM_SC_W2_CALCULATE_F5_LTK: 4012 case SM_SC_W4_CALCULATE_F5_LTK: 4013 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4014 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4015 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4016 case SM_SC_W4_USER_RESPONSE: 4017 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4018 sm_pdu_received_in_wrong_state(sm_conn); 4019 break; 4020 } 4021 // store DHKey Check 4022 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4023 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4024 4025 // have we been only waiting for dhkey check command? 4026 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4027 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4028 } 4029 break; 4030 #endif 4031 4032 #ifdef ENABLE_LE_PERIPHERAL 4033 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4034 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4035 sm_pdu_received_in_wrong_state(sm_conn); 4036 break; 4037 } 4038 4039 // received confirm value 4040 reverse_128(&packet[1], setup->sm_peer_confirm); 4041 4042 #ifdef ENABLE_TESTING_SUPPORT 4043 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4044 log_info("testing_support: reset confirm value"); 4045 memset(setup->sm_peer_confirm, 0, 16); 4046 } 4047 #endif 4048 // notify client to hide shown passkey 4049 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4050 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4051 } 4052 4053 // handle user cancel pairing? 4054 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4055 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4056 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4057 break; 4058 } 4059 4060 // wait for user action? 4061 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4062 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4063 break; 4064 } 4065 4066 // calculate and send local_confirm 4067 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4068 break; 4069 4070 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4071 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4072 sm_pdu_received_in_wrong_state(sm_conn); 4073 break;; 4074 } 4075 4076 // received random value 4077 reverse_128(&packet[1], setup->sm_peer_random); 4078 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4079 break; 4080 #endif 4081 4082 case SM_PH3_RECEIVE_KEYS: 4083 switch(sm_pdu_code){ 4084 case SM_CODE_ENCRYPTION_INFORMATION: 4085 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4086 reverse_128(&packet[1], setup->sm_peer_ltk); 4087 break; 4088 4089 case SM_CODE_MASTER_IDENTIFICATION: 4090 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4091 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4092 reverse_64(&packet[3], setup->sm_peer_rand); 4093 break; 4094 4095 case SM_CODE_IDENTITY_INFORMATION: 4096 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4097 reverse_128(&packet[1], setup->sm_peer_irk); 4098 break; 4099 4100 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4101 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4102 setup->sm_peer_addr_type = packet[1]; 4103 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4104 break; 4105 4106 case SM_CODE_SIGNING_INFORMATION: 4107 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4108 reverse_128(&packet[1], setup->sm_peer_csrk); 4109 break; 4110 default: 4111 // Unexpected PDU 4112 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4113 break; 4114 } 4115 // done with key distribution? 4116 if (sm_key_distribution_all_received(sm_conn)){ 4117 4118 sm_key_distribution_handle_all_received(sm_conn); 4119 4120 if (IS_RESPONDER(sm_conn->sm_role)){ 4121 if (sm_ctkd_from_le(sm_conn)){ 4122 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 4123 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4124 } else { 4125 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4126 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 4127 sm_done_for_handle(sm_conn->sm_handle); 4128 } 4129 } else { 4130 if (setup->sm_use_secure_connections){ 4131 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4132 } else { 4133 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 4134 } 4135 } 4136 } 4137 break; 4138 default: 4139 // Unexpected PDU 4140 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4141 break; 4142 } 4143 4144 // try to send next pdu 4145 sm_trigger_run(); 4146 } 4147 4148 // Security Manager Client API 4149 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4150 sm_get_oob_data = get_oob_data_callback; 4151 } 4152 4153 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)){ 4154 sm_get_sc_oob_data = get_sc_oob_data_callback; 4155 } 4156 4157 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4158 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4159 } 4160 4161 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4162 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4163 } 4164 4165 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4166 sm_min_encryption_key_size = min_size; 4167 sm_max_encryption_key_size = max_size; 4168 } 4169 4170 void sm_set_authentication_requirements(uint8_t auth_req){ 4171 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4172 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4173 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4174 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4175 } 4176 #endif 4177 sm_auth_req = auth_req; 4178 } 4179 4180 void sm_set_io_capabilities(io_capability_t io_capability){ 4181 sm_io_capabilities = io_capability; 4182 } 4183 4184 #ifdef ENABLE_LE_PERIPHERAL 4185 void sm_set_request_security(int enable){ 4186 sm_slave_request_security = enable; 4187 } 4188 #endif 4189 4190 void sm_set_er(sm_key_t er){ 4191 (void)memcpy(sm_persistent_er, er, 16); 4192 } 4193 4194 void sm_set_ir(sm_key_t ir){ 4195 (void)memcpy(sm_persistent_ir, ir, 16); 4196 } 4197 4198 // Testing support only 4199 void sm_test_set_irk(sm_key_t irk){ 4200 (void)memcpy(sm_persistent_irk, irk, 16); 4201 dkg_state = DKG_CALC_DHK; 4202 test_use_fixed_local_irk = true; 4203 } 4204 4205 void sm_test_use_fixed_local_csrk(void){ 4206 test_use_fixed_local_csrk = true; 4207 } 4208 4209 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4210 static void sm_ec_generated(void * arg){ 4211 UNUSED(arg); 4212 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4213 // trigger pairing if pending for ec key 4214 sm_trigger_run(); 4215 } 4216 static void sm_ec_generate_new_key(void){ 4217 log_info("sm: generate new ec key"); 4218 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4219 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4220 } 4221 #endif 4222 4223 #ifdef ENABLE_TESTING_SUPPORT 4224 void sm_test_set_pairing_failure(int reason){ 4225 test_pairing_failure = reason; 4226 } 4227 #endif 4228 4229 void sm_init(void){ 4230 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4231 sm_er_ir_set_default(); 4232 4233 // defaults 4234 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4235 | SM_STK_GENERATION_METHOD_OOB 4236 | SM_STK_GENERATION_METHOD_PASSKEY 4237 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4238 4239 sm_max_encryption_key_size = 16; 4240 sm_min_encryption_key_size = 7; 4241 4242 sm_fixed_passkey_in_display_role = 0xffffffff; 4243 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4244 4245 #ifdef USE_CMAC_ENGINE 4246 sm_cmac_active = 0; 4247 #endif 4248 dkg_state = DKG_W4_WORKING; 4249 rau_state = RAU_IDLE; 4250 sm_aes128_state = SM_AES128_IDLE; 4251 sm_address_resolution_test = -1; // no private address to resolve yet 4252 sm_address_resolution_ah_calculation_active = 0; 4253 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4254 sm_address_resolution_general_queue = NULL; 4255 4256 gap_random_adress_update_period = 15 * 60 * 1000L; 4257 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4258 4259 test_use_fixed_local_csrk = false; 4260 4261 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4262 4263 // register for HCI Events from HCI 4264 hci_event_callback_registration.callback = &sm_event_packet_handler; 4265 hci_add_event_handler(&hci_event_callback_registration); 4266 4267 // 4268 btstack_crypto_init(); 4269 4270 // init le_device_db 4271 le_device_db_init(); 4272 4273 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4274 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4275 4276 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4277 sm_ec_generate_new_key(); 4278 #endif 4279 } 4280 4281 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4282 sm_fixed_passkey_in_display_role = passkey; 4283 } 4284 4285 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4286 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4287 } 4288 4289 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4290 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4291 if (!hci_con) return NULL; 4292 return &hci_con->sm_connection; 4293 } 4294 4295 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4296 switch (sm_conn->sm_engine_state){ 4297 case SM_GENERAL_IDLE: 4298 case SM_RESPONDER_IDLE: 4299 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4300 sm_trigger_run(); 4301 break; 4302 default: 4303 break; 4304 } 4305 } 4306 4307 /** 4308 * @brief Trigger Security Request 4309 */ 4310 void sm_send_security_request(hci_con_handle_t con_handle){ 4311 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4312 if (!sm_conn) return; 4313 sm_send_security_request_for_connection(sm_conn); 4314 } 4315 4316 // request pairing 4317 void sm_request_pairing(hci_con_handle_t con_handle){ 4318 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4319 if (!sm_conn) return; // wrong connection 4320 4321 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4322 if (IS_RESPONDER(sm_conn->sm_role)){ 4323 sm_send_security_request_for_connection(sm_conn); 4324 } else { 4325 // used as a trigger to start central/master/initiator security procedures 4326 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4327 uint8_t ltk[16]; 4328 bool have_ltk; 4329 switch (sm_conn->sm_irk_lookup_state){ 4330 case IRK_LOOKUP_SUCCEEDED: 4331 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4332 have_ltk = !sm_is_null_key(ltk); 4333 log_info("have ltk %u", have_ltk); 4334 if (have_ltk){ 4335 sm_conn->sm_pairing_requested = 1; 4336 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4337 break; 4338 } 4339 /* fall through */ 4340 4341 case IRK_LOOKUP_FAILED: 4342 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4343 break; 4344 default: 4345 log_info("irk lookup pending"); 4346 sm_conn->sm_pairing_requested = 1; 4347 break; 4348 } 4349 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4350 sm_conn->sm_pairing_requested = 1; 4351 } 4352 } 4353 sm_trigger_run(); 4354 } 4355 4356 // called by client app on authorization request 4357 void sm_authorization_decline(hci_con_handle_t con_handle){ 4358 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4359 if (!sm_conn) return; // wrong connection 4360 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4361 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4362 } 4363 4364 void sm_authorization_grant(hci_con_handle_t con_handle){ 4365 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4366 if (!sm_conn) return; // wrong connection 4367 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4368 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4369 } 4370 4371 // GAP Bonding API 4372 4373 void sm_bonding_decline(hci_con_handle_t con_handle){ 4374 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4375 if (!sm_conn) return; // wrong connection 4376 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4377 log_info("decline, state %u", sm_conn->sm_engine_state); 4378 switch(sm_conn->sm_engine_state){ 4379 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4380 case SM_SC_W4_USER_RESPONSE: 4381 case SM_SC_W4_CONFIRMATION: 4382 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4383 #endif 4384 case SM_PH1_W4_USER_RESPONSE: 4385 switch (setup->sm_stk_generation_method){ 4386 case PK_RESP_INPUT: 4387 case PK_INIT_INPUT: 4388 case PK_BOTH_INPUT: 4389 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4390 break; 4391 case NUMERIC_COMPARISON: 4392 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4393 break; 4394 case JUST_WORKS: 4395 case OOB: 4396 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4397 break; 4398 default: 4399 btstack_assert(false); 4400 break; 4401 } 4402 break; 4403 default: 4404 break; 4405 } 4406 sm_trigger_run(); 4407 } 4408 4409 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4410 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4411 if (!sm_conn) return; // wrong connection 4412 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4413 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4414 if (setup->sm_use_secure_connections){ 4415 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4416 } else { 4417 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4418 } 4419 } 4420 4421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4422 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4423 sm_sc_prepare_dhkey_check(sm_conn); 4424 } 4425 #endif 4426 4427 sm_trigger_run(); 4428 } 4429 4430 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4431 // for now, it's the same 4432 sm_just_works_confirm(con_handle); 4433 } 4434 4435 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4436 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4437 if (!sm_conn) return; // wrong connection 4438 sm_reset_tk(); 4439 big_endian_store_32(setup->sm_tk, 12, passkey); 4440 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4441 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4442 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4443 } 4444 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4445 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4446 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4447 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4448 sm_sc_start_calculating_local_confirm(sm_conn); 4449 } 4450 #endif 4451 sm_trigger_run(); 4452 } 4453 4454 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4455 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4456 if (!sm_conn) return; // wrong connection 4457 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4458 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4459 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4460 switch (action){ 4461 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4462 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4463 flags |= (1u << action); 4464 break; 4465 case SM_KEYPRESS_PASSKEY_CLEARED: 4466 // clear counter, keypress & erased flags + set passkey cleared 4467 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4468 break; 4469 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4470 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4471 // erase actions queued 4472 num_actions--; 4473 if (num_actions == 0u){ 4474 // clear counter, keypress & erased flags 4475 flags &= 0x19u; 4476 } 4477 break; 4478 } 4479 num_actions++; 4480 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4481 break; 4482 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4483 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4484 // enter actions queued 4485 num_actions--; 4486 if (num_actions == 0u){ 4487 // clear counter, keypress & erased flags 4488 flags &= 0x19u; 4489 } 4490 break; 4491 } 4492 num_actions++; 4493 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4494 break; 4495 default: 4496 break; 4497 } 4498 setup->sm_keypress_notification = (num_actions << 5) | flags; 4499 sm_trigger_run(); 4500 } 4501 4502 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4503 static void sm_handle_random_result_oob(void * arg){ 4504 UNUSED(arg); 4505 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4506 sm_trigger_run(); 4507 } 4508 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4509 4510 static btstack_crypto_random_t sm_crypto_random_oob_request; 4511 4512 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4513 sm_sc_oob_callback = callback; 4514 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4515 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4516 return 0; 4517 } 4518 #endif 4519 4520 /** 4521 * @brief Get Identity Resolving state 4522 * @param con_handle 4523 * @return irk_lookup_state_t 4524 */ 4525 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4526 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4527 if (!sm_conn) return IRK_LOOKUP_IDLE; 4528 return sm_conn->sm_irk_lookup_state; 4529 } 4530 4531 /** 4532 * @brief Identify device in LE Device DB 4533 * @param handle 4534 * @returns index from le_device_db or -1 if not found/identified 4535 */ 4536 int sm_le_device_index(hci_con_handle_t con_handle ){ 4537 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4538 if (!sm_conn) return -1; 4539 return sm_conn->sm_le_db_index; 4540 } 4541 4542 static int gap_random_address_type_requires_updates(void){ 4543 switch (gap_random_adress_type){ 4544 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4545 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4546 return 0; 4547 default: 4548 return 1; 4549 } 4550 } 4551 4552 static uint8_t own_address_type(void){ 4553 switch (gap_random_adress_type){ 4554 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4555 return BD_ADDR_TYPE_LE_PUBLIC; 4556 default: 4557 return BD_ADDR_TYPE_LE_RANDOM; 4558 } 4559 } 4560 4561 // GAP LE API 4562 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4563 gap_random_address_update_stop(); 4564 gap_random_adress_type = random_address_type; 4565 hci_le_set_own_address_type(own_address_type()); 4566 if (!gap_random_address_type_requires_updates()) return; 4567 gap_random_address_update_start(); 4568 gap_random_address_trigger(); 4569 } 4570 4571 gap_random_address_type_t gap_random_address_get_mode(void){ 4572 return gap_random_adress_type; 4573 } 4574 4575 void gap_random_address_set_update_period(int period_ms){ 4576 gap_random_adress_update_period = period_ms; 4577 if (!gap_random_address_type_requires_updates()) return; 4578 gap_random_address_update_stop(); 4579 gap_random_address_update_start(); 4580 } 4581 4582 void gap_random_address_set(const bd_addr_t addr){ 4583 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4584 (void)memcpy(sm_random_address, addr, 6); 4585 rau_state = RAU_SET_ADDRESS; 4586 sm_trigger_run(); 4587 } 4588 4589 #ifdef ENABLE_LE_PERIPHERAL 4590 /* 4591 * @brief Set Advertisement Paramters 4592 * @param adv_int_min 4593 * @param adv_int_max 4594 * @param adv_type 4595 * @param direct_address_type 4596 * @param direct_address 4597 * @param channel_map 4598 * @param filter_policy 4599 * 4600 * @note own_address_type is used from gap_random_address_set_mode 4601 */ 4602 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4603 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4604 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4605 direct_address_typ, direct_address, channel_map, filter_policy); 4606 } 4607 #endif 4608 4609 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4610 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4611 // wrong connection 4612 if (!sm_conn) return 0; 4613 // already encrypted 4614 if (sm_conn->sm_connection_encrypted) return 0; 4615 // only central can re-encrypt 4616 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4617 // irk status? 4618 switch(sm_conn->sm_irk_lookup_state){ 4619 case IRK_LOOKUP_FAILED: 4620 // done, cannot setup encryption 4621 return 0; 4622 case IRK_LOOKUP_SUCCEEDED: 4623 break; 4624 default: 4625 // IR Lookup pending 4626 return 1; 4627 } 4628 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4629 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4630 } 4631 4632 void sm_set_secure_connections_only_mode(bool enable){ 4633 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4634 sm_sc_only_mode = enable; 4635 #else 4636 // SC Only mode not possible without support for SC 4637 btstack_assert(enable == false); 4638 #endif 4639 } 4640 4641 const uint8_t * gap_get_persistent_irk(void){ 4642 return sm_persistent_irk; 4643 } 4644