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 static void sm_notify_client_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 749 // fetch addr and addr type from db, only called for valid entries 750 int identity_addr_type; 751 bd_addr_t identity_addr; 752 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 753 754 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 755 } 756 757 // decide on stk generation based on 758 // - pairing request 759 // - io capabilities 760 // - OOB data availability 761 static void sm_setup_tk(void){ 762 763 // horizontal: initiator capabilities 764 // vertial: responder capabilities 765 static const stk_generation_method_t stk_generation_method [5] [5] = { 766 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 767 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 768 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 769 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 770 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 771 }; 772 773 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 774 #ifdef ENABLE_LE_SECURE_CONNECTIONS 775 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 776 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 777 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 778 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 779 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 780 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 781 }; 782 #endif 783 784 // default: just works 785 setup->sm_stk_generation_method = JUST_WORKS; 786 787 #ifdef ENABLE_LE_SECURE_CONNECTIONS 788 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 789 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 790 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 791 #else 792 setup->sm_use_secure_connections = 0; 793 #endif 794 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 795 796 797 // decide if OOB will be used based on SC vs. Legacy and oob flags 798 int use_oob = 0; 799 if (setup->sm_use_secure_connections){ 800 // In LE Secure Connections pairing, the out of band method is used if at least 801 // one device has the peer device's out of band authentication data available. 802 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 803 } else { 804 // In LE legacy pairing, the out of band method is used if both the devices have 805 // the other device's out of band authentication data available. 806 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 807 } 808 if (use_oob){ 809 log_info("SM: have OOB data"); 810 log_info_key("OOB", setup->sm_tk); 811 setup->sm_stk_generation_method = OOB; 812 return; 813 } 814 815 // If both devices have not set the MITM option in the Authentication Requirements 816 // Flags, then the IO capabilities shall be ignored and the Just Works association 817 // model shall be used. 818 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 819 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 820 log_info("SM: MITM not required by both -> JUST WORKS"); 821 return; 822 } 823 824 // Reset TK as it has been setup in sm_init_setup 825 sm_reset_tk(); 826 827 // Also use just works if unknown io capabilites 828 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)){ 829 return; 830 } 831 832 // Otherwise the IO capabilities of the devices shall be used to determine the 833 // pairing method as defined in Table 2.4. 834 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 835 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 836 837 #ifdef ENABLE_LE_SECURE_CONNECTIONS 838 // table not define by default 839 if (setup->sm_use_secure_connections){ 840 generation_method = stk_generation_method_with_secure_connection; 841 } 842 #endif 843 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)]; 844 845 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 846 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); 847 } 848 849 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 850 int flags = 0; 851 if (key_set & SM_KEYDIST_ENC_KEY){ 852 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 853 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 854 } 855 if (key_set & SM_KEYDIST_ID_KEY){ 856 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 857 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 858 } 859 if (key_set & SM_KEYDIST_SIGN){ 860 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 861 } 862 return flags; 863 } 864 865 static void sm_setup_key_distribution(uint8_t key_set){ 866 setup->sm_key_distribution_received_set = 0; 867 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 868 setup->sm_key_distribution_sent_set = 0; 869 #ifdef ENABLE_LE_SIGNED_WRITE 870 setup->sm_le_device_index = -1; 871 #endif 872 } 873 874 // CSRK Key Lookup 875 876 877 static int sm_address_resolution_idle(void){ 878 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 879 } 880 881 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){ 882 (void)memcpy(sm_address_resolution_address, addr, 6); 883 sm_address_resolution_addr_type = addr_type; 884 sm_address_resolution_test = 0; 885 sm_address_resolution_mode = mode; 886 sm_address_resolution_context = context; 887 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 888 } 889 890 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 891 // check if already in list 892 btstack_linked_list_iterator_t it; 893 sm_lookup_entry_t * entry; 894 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 895 while(btstack_linked_list_iterator_has_next(&it)){ 896 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 897 if (entry->address_type != address_type) continue; 898 if (memcmp(entry->address, address, 6)) continue; 899 // already in list 900 return BTSTACK_BUSY; 901 } 902 entry = btstack_memory_sm_lookup_entry_get(); 903 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 904 entry->address_type = (bd_addr_type_t) address_type; 905 (void)memcpy(entry->address, address, 6); 906 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 907 sm_trigger_run(); 908 return 0; 909 } 910 911 // CMAC calculation using AES Engineq 912 #ifdef USE_CMAC_ENGINE 913 914 static void sm_cmac_done_trampoline(void * arg){ 915 UNUSED(arg); 916 sm_cmac_active = 0; 917 (*sm_cmac_done_callback)(sm_cmac_hash); 918 sm_trigger_run(); 919 } 920 921 int sm_cmac_ready(void){ 922 return sm_cmac_active == 0u; 923 } 924 #endif 925 926 #ifdef ENABLE_LE_SECURE_CONNECTIONS 927 // generic cmac calculation 928 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)){ 929 sm_cmac_active = 1; 930 sm_cmac_done_callback = done_callback; 931 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 932 } 933 #endif 934 935 // cmac for ATT Message signing 936 #ifdef ENABLE_LE_SIGNED_WRITE 937 938 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)){ 939 sm_cmac_active = 1; 940 sm_cmac_done_callback = done_callback; 941 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 942 } 943 944 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 945 if (offset >= sm_cmac_signed_write_message_len) { 946 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 947 return 0; 948 } 949 950 offset = sm_cmac_signed_write_message_len - 1 - offset; 951 952 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 953 if (offset < 3){ 954 return sm_cmac_signed_write_header[offset]; 955 } 956 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 957 if (offset < actual_message_len_incl_header){ 958 return sm_cmac_signed_write_message[offset - 3]; 959 } 960 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 961 } 962 963 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)){ 964 // ATT Message Signing 965 sm_cmac_signed_write_header[0] = opcode; 966 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 967 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 968 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 969 sm_cmac_signed_write_message = message; 970 sm_cmac_signed_write_message_len = total_message_len; 971 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 972 } 973 #endif 974 975 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 976 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 977 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 978 switch (setup->sm_stk_generation_method){ 979 case PK_RESP_INPUT: 980 if (IS_RESPONDER(sm_conn->sm_role)){ 981 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 982 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 983 } else { 984 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)); 985 } 986 break; 987 case PK_INIT_INPUT: 988 if (IS_RESPONDER(sm_conn->sm_role)){ 989 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)); 990 } else { 991 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 992 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 993 } 994 break; 995 case PK_BOTH_INPUT: 996 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 997 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 998 break; 999 case NUMERIC_COMPARISON: 1000 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1001 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)); 1002 break; 1003 case JUST_WORKS: 1004 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1005 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1006 break; 1007 case OOB: 1008 // client already provided OOB data, let's skip notification. 1009 break; 1010 default: 1011 btstack_assert(false); 1012 break; 1013 } 1014 } 1015 1016 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1017 int recv_flags; 1018 if (IS_RESPONDER(sm_conn->sm_role)){ 1019 // slave / responder 1020 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1021 } else { 1022 // master / initiator 1023 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1024 } 1025 1026 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1027 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1028 if (setup->sm_use_secure_connections){ 1029 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1030 } 1031 #endif 1032 1033 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1034 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1035 } 1036 1037 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1038 if (sm_active_connection_handle == con_handle){ 1039 sm_timeout_stop(); 1040 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1041 log_info("sm: connection 0x%x released setup context", con_handle); 1042 1043 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1044 // generate new ec key after each pairing (that used it) 1045 if (setup->sm_use_secure_connections){ 1046 sm_ec_generate_new_key(); 1047 } 1048 #endif 1049 } 1050 } 1051 1052 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1053 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1054 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1055 sm_done_for_handle(connection->sm_handle); 1056 } 1057 1058 static int sm_key_distribution_flags_for_auth_req(void){ 1059 1060 int flags = SM_KEYDIST_ID_KEY; 1061 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1062 // encryption and signing information only if bonding requested 1063 flags |= SM_KEYDIST_ENC_KEY; 1064 #ifdef ENABLE_LE_SIGNED_WRITE 1065 flags |= SM_KEYDIST_SIGN; 1066 #endif 1067 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1068 // LinkKey for CTKD requires SC 1069 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1070 flags |= SM_KEYDIST_LINK_KEY; 1071 } 1072 #endif 1073 } 1074 return flags; 1075 } 1076 1077 static void sm_reset_setup(void){ 1078 // fill in sm setup 1079 setup->sm_state_vars = 0; 1080 setup->sm_keypress_notification = 0; 1081 sm_reset_tk(); 1082 } 1083 1084 static void sm_init_setup(sm_connection_t * sm_conn){ 1085 1086 // fill in sm setup 1087 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1088 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1089 1090 // query client for Legacy Pairing OOB data 1091 setup->sm_have_oob_data = 0; 1092 if (sm_get_oob_data) { 1093 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1094 } 1095 1096 // if available and SC supported, also ask for SC OOB Data 1097 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1098 memset(setup->sm_ra, 0, 16); 1099 memset(setup->sm_rb, 0, 16); 1100 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1101 if (sm_get_sc_oob_data){ 1102 if (IS_RESPONDER(sm_conn->sm_role)){ 1103 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1104 sm_conn->sm_peer_addr_type, 1105 sm_conn->sm_peer_address, 1106 setup->sm_peer_confirm, 1107 setup->sm_ra); 1108 } else { 1109 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1110 sm_conn->sm_peer_addr_type, 1111 sm_conn->sm_peer_address, 1112 setup->sm_peer_confirm, 1113 setup->sm_rb); 1114 } 1115 } else { 1116 setup->sm_have_oob_data = 0; 1117 } 1118 } 1119 #endif 1120 1121 sm_pairing_packet_t * local_packet; 1122 if (IS_RESPONDER(sm_conn->sm_role)){ 1123 // slave 1124 local_packet = &setup->sm_s_pres; 1125 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1126 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1127 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1128 } else { 1129 // master 1130 local_packet = &setup->sm_m_preq; 1131 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1132 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1133 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1134 1135 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1136 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1137 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1138 } 1139 1140 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1141 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1142 // set CT2 if SC + Bonding + CTKD 1143 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1144 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1145 auth_req |= SM_AUTHREQ_CT2; 1146 } 1147 #endif 1148 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1149 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1150 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1151 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1152 } 1153 1154 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1155 1156 sm_pairing_packet_t * remote_packet; 1157 int remote_key_request; 1158 if (IS_RESPONDER(sm_conn->sm_role)){ 1159 // slave / responder 1160 remote_packet = &setup->sm_m_preq; 1161 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1162 } else { 1163 // master / initiator 1164 remote_packet = &setup->sm_s_pres; 1165 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1166 } 1167 1168 // check key size 1169 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1170 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1171 1172 // decide on STK generation method / SC 1173 sm_setup_tk(); 1174 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1175 1176 // check if STK generation method is acceptable by client 1177 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1178 1179 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1180 // check LE SC Only mode 1181 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1182 log_info("SC Only mode active but SC not possible"); 1183 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1184 } 1185 1186 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1187 if (setup->sm_use_secure_connections){ 1188 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1189 } 1190 #endif 1191 1192 // identical to responder 1193 sm_setup_key_distribution(remote_key_request); 1194 1195 // JUST WORKS doens't provide authentication 1196 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1197 1198 return 0; 1199 } 1200 1201 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1202 1203 // cache and reset context 1204 int matched_device_id = sm_address_resolution_test; 1205 address_resolution_mode_t mode = sm_address_resolution_mode; 1206 void * context = sm_address_resolution_context; 1207 1208 // reset context 1209 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1210 sm_address_resolution_context = NULL; 1211 sm_address_resolution_test = -1; 1212 hci_con_handle_t con_handle = 0; 1213 1214 sm_connection_t * sm_connection; 1215 sm_key_t ltk; 1216 int have_ltk; 1217 #ifdef ENABLE_LE_CENTRAL 1218 int trigger_pairing; 1219 #endif 1220 switch (mode){ 1221 case ADDRESS_RESOLUTION_GENERAL: 1222 break; 1223 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1224 sm_connection = (sm_connection_t *) context; 1225 con_handle = sm_connection->sm_handle; 1226 1227 // have ltk -> start encryption / send security request 1228 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1229 // "When a bond has been created between two devices, any reconnection should result in the local device 1230 // enabling or requesting encryption with the remote device before initiating any service request." 1231 1232 switch (event){ 1233 case ADDRESS_RESOLUTION_SUCCEEDED: 1234 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1235 sm_connection->sm_le_db_index = matched_device_id; 1236 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1237 1238 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1239 have_ltk = !sm_is_null_key(ltk); 1240 1241 if (sm_connection->sm_role) { 1242 1243 #ifdef ENABLE_LE_PERIPHERAL 1244 1245 // LTK request received before, IRK required -> start LTK calculation 1246 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1247 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1248 break; 1249 } 1250 1251 if (have_ltk) { 1252 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1253 log_info("central: enable encryption for bonded device"); 1254 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1255 sm_trigger_run(); 1256 #else 1257 log_info("central: defer security request for bonded device"); 1258 #endif 1259 } 1260 #endif 1261 } else { 1262 1263 #ifdef ENABLE_LE_CENTRAL 1264 1265 // check if pairing already requested and reset requests 1266 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1267 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1268 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, trigger_pairing, have_ltk); 1269 sm_connection->sm_security_request_received = 0; 1270 sm_connection->sm_pairing_requested = 0; 1271 1272 if (have_ltk){ 1273 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1274 log_info("central: enable encryption for bonded device"); 1275 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1276 break; 1277 #else 1278 log_info("central: defer enabling encryption for bonded device"); 1279 #endif 1280 } 1281 1282 // pairing_request -> send pairing request 1283 if (trigger_pairing){ 1284 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1285 break; 1286 } 1287 } 1288 #endif 1289 break; 1290 case ADDRESS_RESOLUTION_FAILED: 1291 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1292 if (sm_connection->sm_role) { 1293 // LTK request received before, IRK required -> negative LTK reply 1294 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1295 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1296 } 1297 break; 1298 } 1299 #ifdef ENABLE_LE_CENTRAL 1300 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1301 sm_connection->sm_security_request_received = 0; 1302 sm_connection->sm_pairing_requested = 0; 1303 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1304 #endif 1305 break; 1306 1307 default: 1308 btstack_assert(false); 1309 break; 1310 } 1311 break; 1312 default: 1313 break; 1314 } 1315 1316 switch (event){ 1317 case ADDRESS_RESOLUTION_SUCCEEDED: 1318 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1319 break; 1320 case ADDRESS_RESOLUTION_FAILED: 1321 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1322 break; 1323 default: 1324 btstack_assert(false); 1325 break; 1326 } 1327 } 1328 1329 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1330 1331 int le_db_index = -1; 1332 1333 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1334 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1335 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1336 & SM_AUTHREQ_BONDING ) != 0u; 1337 1338 if (bonding_enabed){ 1339 1340 // lookup device based on IRK 1341 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1342 int i; 1343 for (i=0; i < le_device_db_max_count(); i++){ 1344 sm_key_t irk; 1345 bd_addr_t address; 1346 int address_type = BD_ADDR_TYPE_UNKNOWN; 1347 le_device_db_info(i, &address_type, address, irk); 1348 // skip unused entries 1349 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1350 // compare IRK 1351 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1352 1353 log_info("sm: device found for IRK, updating"); 1354 le_db_index = i; 1355 break; 1356 } 1357 } else { 1358 // assert IRK is set to zero 1359 memset(setup->sm_peer_irk, 0, 16); 1360 } 1361 1362 // if not found, lookup via public address if possible 1363 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1364 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1365 int i; 1366 for (i=0; i < le_device_db_max_count(); i++){ 1367 bd_addr_t address; 1368 int address_type = BD_ADDR_TYPE_UNKNOWN; 1369 le_device_db_info(i, &address_type, address, NULL); 1370 // skip unused entries 1371 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1372 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1373 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1374 log_info("sm: device found for public address, updating"); 1375 le_db_index = i; 1376 break; 1377 } 1378 } 1379 } 1380 1381 // if not found, add to db 1382 bool new_to_le_device_db = false; 1383 if (le_db_index < 0) { 1384 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1385 new_to_le_device_db = true; 1386 } 1387 1388 if (le_db_index >= 0){ 1389 1390 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1391 if (!new_to_le_device_db){ 1392 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1393 } 1394 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1395 #else 1396 UNUSED(new_to_le_device_db); 1397 #endif 1398 1399 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1400 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1401 1402 #ifdef ENABLE_LE_SIGNED_WRITE 1403 // store local CSRK 1404 setup->sm_le_device_index = le_db_index; 1405 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1406 log_info("sm: store local CSRK"); 1407 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1408 le_device_db_local_counter_set(le_db_index, 0); 1409 } 1410 1411 // store remote CSRK 1412 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1413 log_info("sm: store remote CSRK"); 1414 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1415 le_device_db_remote_counter_set(le_db_index, 0); 1416 } 1417 #endif 1418 // store encryption information for secure connections: LTK generated by ECDH 1419 if (setup->sm_use_secure_connections){ 1420 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1421 uint8_t zero_rand[8]; 1422 memset(zero_rand, 0, 8); 1423 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1424 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1425 } 1426 1427 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1428 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1429 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1430 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1431 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1432 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1433 1434 } 1435 } 1436 } else { 1437 log_info("Ignoring received keys, bonding not enabled"); 1438 } 1439 1440 // keep le_db_index 1441 sm_conn->sm_le_db_index = le_db_index; 1442 } 1443 1444 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1445 setup->sm_pairing_failed_reason = reason; 1446 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1447 } 1448 1449 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1450 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1451 } 1452 1453 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1454 1455 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1456 static int sm_passkey_used(stk_generation_method_t method); 1457 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1458 1459 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1460 if (setup->sm_stk_generation_method == OOB){ 1461 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1462 } else { 1463 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); 1464 } 1465 } 1466 1467 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1468 if (IS_RESPONDER(sm_conn->sm_role)){ 1469 // Responder 1470 if (setup->sm_stk_generation_method == OOB){ 1471 // generate Nb 1472 log_info("Generate Nb"); 1473 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); 1474 } else { 1475 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1476 } 1477 } else { 1478 // Initiator role 1479 switch (setup->sm_stk_generation_method){ 1480 case JUST_WORKS: 1481 sm_sc_prepare_dhkey_check(sm_conn); 1482 break; 1483 1484 case NUMERIC_COMPARISON: 1485 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1486 break; 1487 case PK_INIT_INPUT: 1488 case PK_RESP_INPUT: 1489 case PK_BOTH_INPUT: 1490 if (setup->sm_passkey_bit < 20u) { 1491 sm_sc_start_calculating_local_confirm(sm_conn); 1492 } else { 1493 sm_sc_prepare_dhkey_check(sm_conn); 1494 } 1495 break; 1496 case OOB: 1497 sm_sc_prepare_dhkey_check(sm_conn); 1498 break; 1499 default: 1500 btstack_assert(false); 1501 break; 1502 } 1503 } 1504 } 1505 1506 static void sm_sc_cmac_done(uint8_t * hash){ 1507 log_info("sm_sc_cmac_done: "); 1508 log_info_hexdump(hash, 16); 1509 1510 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1511 sm_sc_oob_state = SM_SC_OOB_IDLE; 1512 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1513 return; 1514 } 1515 1516 sm_connection_t * sm_conn = sm_cmac_connection; 1517 sm_cmac_connection = NULL; 1518 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1519 link_key_type_t link_key_type; 1520 #endif 1521 1522 switch (sm_conn->sm_engine_state){ 1523 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1524 (void)memcpy(setup->sm_local_confirm, hash, 16); 1525 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1526 break; 1527 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1528 // check 1529 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1530 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1531 break; 1532 } 1533 sm_sc_state_after_receiving_random(sm_conn); 1534 break; 1535 case SM_SC_W4_CALCULATE_G2: { 1536 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1537 big_endian_store_32(setup->sm_tk, 12, vab); 1538 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1539 sm_trigger_user_response(sm_conn); 1540 break; 1541 } 1542 case SM_SC_W4_CALCULATE_F5_SALT: 1543 (void)memcpy(setup->sm_t, hash, 16); 1544 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1545 break; 1546 case SM_SC_W4_CALCULATE_F5_MACKEY: 1547 (void)memcpy(setup->sm_mackey, hash, 16); 1548 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1549 break; 1550 case SM_SC_W4_CALCULATE_F5_LTK: 1551 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1552 // Errata Service Release to the Bluetooth Specification: ESR09 1553 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1554 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1555 (void)memcpy(setup->sm_ltk, hash, 16); 1556 (void)memcpy(setup->sm_local_ltk, hash, 16); 1557 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1558 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1559 break; 1560 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1561 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1562 if (IS_RESPONDER(sm_conn->sm_role)){ 1563 // responder 1564 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1565 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1566 } else { 1567 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1568 } 1569 } else { 1570 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1571 } 1572 break; 1573 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1574 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1575 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1576 break; 1577 } 1578 if (IS_RESPONDER(sm_conn->sm_role)){ 1579 // responder 1580 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1581 } else { 1582 // initiator 1583 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1584 } 1585 break; 1586 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1587 case SM_SC_W4_CALCULATE_ILK: 1588 (void)memcpy(setup->sm_t, hash, 16); 1589 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1590 break; 1591 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1592 reverse_128(hash, setup->sm_t); 1593 link_key_type = sm_conn->sm_connection_authenticated ? 1594 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1595 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1596 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1597 if (IS_RESPONDER(sm_conn->sm_role)){ 1598 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1599 } else { 1600 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1601 } 1602 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1603 sm_done_for_handle(sm_conn->sm_handle); 1604 break; 1605 #endif 1606 default: 1607 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1608 break; 1609 } 1610 sm_trigger_run(); 1611 } 1612 1613 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){ 1614 const uint16_t message_len = 65; 1615 sm_cmac_connection = sm_conn; 1616 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1617 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1618 sm_cmac_sc_buffer[64] = z; 1619 log_info("f4 key"); 1620 log_info_hexdump(x, 16); 1621 log_info("f4 message"); 1622 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1623 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1624 } 1625 1626 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1627 static const uint8_t f5_length[] = { 0x01, 0x00}; 1628 1629 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1630 1631 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1632 1633 log_info("f5_calculate_salt"); 1634 // calculate salt for f5 1635 const uint16_t message_len = 32; 1636 sm_cmac_connection = sm_conn; 1637 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1638 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1639 } 1640 1641 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){ 1642 const uint16_t message_len = 53; 1643 sm_cmac_connection = sm_conn; 1644 1645 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1646 sm_cmac_sc_buffer[0] = 0; 1647 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1648 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1649 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1650 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1651 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1652 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1653 log_info("f5 key"); 1654 log_info_hexdump(t, 16); 1655 log_info("f5 message for MacKey"); 1656 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1657 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1658 } 1659 1660 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1661 sm_key56_t bd_addr_master, bd_addr_slave; 1662 bd_addr_master[0] = setup->sm_m_addr_type; 1663 bd_addr_slave[0] = setup->sm_s_addr_type; 1664 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1665 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1666 if (IS_RESPONDER(sm_conn->sm_role)){ 1667 // responder 1668 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1669 } else { 1670 // initiator 1671 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1672 } 1673 } 1674 1675 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1676 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1677 const uint16_t message_len = 53; 1678 sm_cmac_connection = sm_conn; 1679 sm_cmac_sc_buffer[0] = 1; 1680 // 1..52 setup before 1681 log_info("f5 key"); 1682 log_info_hexdump(t, 16); 1683 log_info("f5 message for LTK"); 1684 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1685 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1686 } 1687 1688 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1689 f5_ltk(sm_conn, setup->sm_t); 1690 } 1691 1692 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){ 1693 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1694 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1695 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1696 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1697 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1698 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1699 } 1700 1701 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1702 const uint16_t message_len = 65; 1703 sm_cmac_connection = sm_conn; 1704 log_info("f6 key"); 1705 log_info_hexdump(w, 16); 1706 log_info("f6 message"); 1707 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1708 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1709 } 1710 1711 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1712 // - U is 256 bits 1713 // - V is 256 bits 1714 // - X is 128 bits 1715 // - Y is 128 bits 1716 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){ 1717 const uint16_t message_len = 80; 1718 sm_cmac_connection = sm_conn; 1719 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1720 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1721 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1722 log_info("g2 key"); 1723 log_info_hexdump(x, 16); 1724 log_info("g2 message"); 1725 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1726 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1727 } 1728 1729 static void g2_calculate(sm_connection_t * sm_conn) { 1730 // calc Va if numeric comparison 1731 if (IS_RESPONDER(sm_conn->sm_role)){ 1732 // responder 1733 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1734 } else { 1735 // initiator 1736 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1737 } 1738 } 1739 1740 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1741 uint8_t z = 0; 1742 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1743 // some form of passkey 1744 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1745 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1746 setup->sm_passkey_bit++; 1747 } 1748 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1749 } 1750 1751 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1752 // OOB 1753 if (setup->sm_stk_generation_method == OOB){ 1754 if (IS_RESPONDER(sm_conn->sm_role)){ 1755 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1756 } else { 1757 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1758 } 1759 return; 1760 } 1761 1762 uint8_t z = 0; 1763 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1764 // some form of passkey 1765 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1766 // sm_passkey_bit was increased before sending confirm value 1767 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1768 } 1769 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1770 } 1771 1772 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1773 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1774 1775 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1776 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1777 return; 1778 } else { 1779 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1780 } 1781 } 1782 1783 static void sm_sc_dhkey_calculated(void * arg){ 1784 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1785 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1786 if (sm_conn == NULL) return; 1787 1788 log_info("dhkey"); 1789 log_info_hexdump(&setup->sm_dhkey[0], 32); 1790 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1791 // trigger next step 1792 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1793 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1794 } 1795 sm_trigger_run(); 1796 } 1797 1798 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1799 // calculate DHKCheck 1800 sm_key56_t bd_addr_master, bd_addr_slave; 1801 bd_addr_master[0] = setup->sm_m_addr_type; 1802 bd_addr_slave[0] = setup->sm_s_addr_type; 1803 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1804 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1805 uint8_t iocap_a[3]; 1806 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1807 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1808 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1809 uint8_t iocap_b[3]; 1810 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1811 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1812 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1813 if (IS_RESPONDER(sm_conn->sm_role)){ 1814 // responder 1815 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1816 f6_engine(sm_conn, setup->sm_mackey); 1817 } else { 1818 // initiator 1819 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1820 f6_engine(sm_conn, setup->sm_mackey); 1821 } 1822 } 1823 1824 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1825 // validate E = f6() 1826 sm_key56_t bd_addr_master, bd_addr_slave; 1827 bd_addr_master[0] = setup->sm_m_addr_type; 1828 bd_addr_slave[0] = setup->sm_s_addr_type; 1829 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1830 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1831 1832 uint8_t iocap_a[3]; 1833 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1834 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1835 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1836 uint8_t iocap_b[3]; 1837 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1838 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1839 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1840 if (IS_RESPONDER(sm_conn->sm_role)){ 1841 // responder 1842 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1843 f6_engine(sm_conn, setup->sm_mackey); 1844 } else { 1845 // initiator 1846 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1847 f6_engine(sm_conn, setup->sm_mackey); 1848 } 1849 } 1850 1851 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1852 1853 // 1854 // Link Key Conversion Function h6 1855 // 1856 // h6(W, keyID) = AES-CMAC_W(keyID) 1857 // - W is 128 bits 1858 // - keyID is 32 bits 1859 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1860 const uint16_t message_len = 4; 1861 sm_cmac_connection = sm_conn; 1862 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1863 log_info("h6 key"); 1864 log_info_hexdump(w, 16); 1865 log_info("h6 message"); 1866 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1867 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1868 } 1869 // 1870 // Link Key Conversion Function h7 1871 // 1872 // h7(SALT, W) = AES-CMAC_SALT(W) 1873 // - SALT is 128 bits 1874 // - W is 128 bits 1875 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1876 const uint16_t message_len = 16; 1877 sm_cmac_connection = sm_conn; 1878 log_info("h7 key"); 1879 log_info_hexdump(salt, 16); 1880 log_info("h7 message"); 1881 log_info_hexdump(w, 16); 1882 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1883 } 1884 1885 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1886 // Errata Service Release to the Bluetooth Specification: ESR09 1887 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1888 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1889 1890 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1891 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1892 } 1893 1894 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1895 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1896 } 1897 1898 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1899 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1900 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1901 } 1902 #endif 1903 1904 #endif 1905 1906 // key management legacy connections: 1907 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1908 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1909 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1910 // - responder reconnects: responder uses LTK receveived from master 1911 1912 // key management secure connections: 1913 // - both devices store same LTK from ECDH key exchange. 1914 1915 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1916 static void sm_load_security_info(sm_connection_t * sm_connection){ 1917 int encryption_key_size; 1918 int authenticated; 1919 int authorized; 1920 int secure_connection; 1921 1922 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1923 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1924 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1925 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); 1926 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1927 sm_connection->sm_connection_authenticated = authenticated; 1928 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1929 sm_connection->sm_connection_sc = secure_connection; 1930 } 1931 #endif 1932 1933 #ifdef ENABLE_LE_PERIPHERAL 1934 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1935 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1936 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1937 // re-establish used key encryption size 1938 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1939 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1940 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1941 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1942 // Legacy paring -> not SC 1943 sm_connection->sm_connection_sc = 0; 1944 log_info("sm: received ltk request with key size %u, authenticated %u", 1945 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1946 } 1947 #endif 1948 1949 // distributed key generation 1950 static bool sm_run_dpkg(void){ 1951 switch (dkg_state){ 1952 case DKG_CALC_IRK: 1953 // already busy? 1954 if (sm_aes128_state == SM_AES128_IDLE) { 1955 log_info("DKG_CALC_IRK started"); 1956 // IRK = d1(IR, 1, 0) 1957 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1958 sm_aes128_state = SM_AES128_ACTIVE; 1959 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1960 return true; 1961 } 1962 break; 1963 case DKG_CALC_DHK: 1964 // already busy? 1965 if (sm_aes128_state == SM_AES128_IDLE) { 1966 log_info("DKG_CALC_DHK started"); 1967 // DHK = d1(IR, 3, 0) 1968 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1969 sm_aes128_state = SM_AES128_ACTIVE; 1970 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1971 return true; 1972 } 1973 break; 1974 default: 1975 break; 1976 } 1977 return false; 1978 } 1979 1980 // random address updates 1981 static bool sm_run_rau(void){ 1982 switch (rau_state){ 1983 case RAU_GET_RANDOM: 1984 rau_state = RAU_W4_RANDOM; 1985 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1986 return true; 1987 case RAU_GET_ENC: 1988 // already busy? 1989 if (sm_aes128_state == SM_AES128_IDLE) { 1990 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1991 sm_aes128_state = SM_AES128_ACTIVE; 1992 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1993 return true; 1994 } 1995 break; 1996 case RAU_SET_ADDRESS: 1997 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1998 rau_state = RAU_IDLE; 1999 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2000 return true; 2001 default: 2002 break; 2003 } 2004 return false; 2005 } 2006 2007 // CSRK Lookup 2008 static bool sm_run_csrk(void){ 2009 btstack_linked_list_iterator_t it; 2010 2011 // -- if csrk lookup ready, find connection that require csrk lookup 2012 if (sm_address_resolution_idle()){ 2013 hci_connections_get_iterator(&it); 2014 while(btstack_linked_list_iterator_has_next(&it)){ 2015 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2016 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2017 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2018 // and start lookup 2019 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); 2020 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2021 break; 2022 } 2023 } 2024 } 2025 2026 // -- if csrk lookup ready, resolved addresses for received addresses 2027 if (sm_address_resolution_idle()) { 2028 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2029 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2030 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2031 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2032 btstack_memory_sm_lookup_entry_free(entry); 2033 } 2034 } 2035 2036 // -- Continue with CSRK device lookup by public or resolvable private address 2037 if (!sm_address_resolution_idle()){ 2038 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2039 while (sm_address_resolution_test < le_device_db_max_count()){ 2040 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2041 bd_addr_t addr; 2042 sm_key_t irk; 2043 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2044 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2045 2046 // skip unused entries 2047 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2048 sm_address_resolution_test++; 2049 continue; 2050 } 2051 2052 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2053 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2054 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2055 break; 2056 } 2057 2058 // if connection type is public, it must be a different one 2059 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2060 sm_address_resolution_test++; 2061 continue; 2062 } 2063 2064 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2065 2066 log_info("LE Device Lookup: calculate AH"); 2067 log_info_key("IRK", irk); 2068 2069 (void)memcpy(sm_aes128_key, irk, 16); 2070 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2071 sm_address_resolution_ah_calculation_active = 1; 2072 sm_aes128_state = SM_AES128_ACTIVE; 2073 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2074 return true; 2075 } 2076 2077 if (sm_address_resolution_test >= le_device_db_max_count()){ 2078 log_info("LE Device Lookup: not found"); 2079 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2080 } 2081 } 2082 return false; 2083 } 2084 2085 // SC OOB 2086 static bool sm_run_oob(void){ 2087 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2088 switch (sm_sc_oob_state){ 2089 case SM_SC_OOB_W2_CALC_CONFIRM: 2090 if (!sm_cmac_ready()) break; 2091 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2092 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2093 return true; 2094 default: 2095 break; 2096 } 2097 #endif 2098 return false; 2099 } 2100 2101 // handle basic actions that don't requires the full context 2102 static bool sm_run_basic(void){ 2103 btstack_linked_list_iterator_t it; 2104 hci_connections_get_iterator(&it); 2105 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2106 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2107 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2108 switch(sm_connection->sm_engine_state){ 2109 // responder side 2110 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 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 2115 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2116 case SM_SC_RECEIVED_LTK_REQUEST: 2117 switch (sm_connection->sm_irk_lookup_state){ 2118 case IRK_LOOKUP_FAILED: 2119 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2120 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2121 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2122 return true; 2123 default: 2124 break; 2125 } 2126 break; 2127 #endif 2128 default: 2129 break; 2130 } 2131 } 2132 return false; 2133 } 2134 2135 static void sm_run_activate_connection(void){ 2136 // Find connections that requires setup context and make active if no other is locked 2137 btstack_linked_list_iterator_t it; 2138 hci_connections_get_iterator(&it); 2139 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2140 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2141 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2142 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2143 int done = 1; 2144 int err; 2145 UNUSED(err); 2146 2147 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2148 // assert ec key is ready 2149 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2150 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2151 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2152 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2153 sm_ec_generate_new_key(); 2154 } 2155 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2156 continue; 2157 } 2158 } 2159 #endif 2160 2161 switch (sm_connection->sm_engine_state) { 2162 #ifdef ENABLE_LE_PERIPHERAL 2163 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2164 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2165 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2166 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2167 case SM_SC_RECEIVED_LTK_REQUEST: 2168 #endif 2169 #endif 2170 #ifdef ENABLE_LE_CENTRAL 2171 case SM_INITIATOR_PH0_HAS_LTK: 2172 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2173 #endif 2174 // just lock context 2175 break; 2176 default: 2177 done = 0; 2178 break; 2179 } 2180 if (done){ 2181 sm_active_connection_handle = sm_connection->sm_handle; 2182 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); 2183 } 2184 } 2185 } 2186 2187 static void sm_run(void){ 2188 2189 // assert that stack has already bootet 2190 if (hci_get_state() != HCI_STATE_WORKING) return; 2191 2192 // assert that we can send at least commands 2193 if (!hci_can_send_command_packet_now()) return; 2194 2195 // pause until IR/ER are ready 2196 if (sm_persistent_keys_random_active) return; 2197 2198 bool done; 2199 2200 // 2201 // non-connection related behaviour 2202 // 2203 2204 done = sm_run_dpkg(); 2205 if (done) return; 2206 2207 done = sm_run_rau(); 2208 if (done) return; 2209 2210 done = sm_run_csrk(); 2211 if (done) return; 2212 2213 done = sm_run_oob(); 2214 if (done) return; 2215 2216 // assert that we can send at least commands - cmd might have been sent by crypto engine 2217 if (!hci_can_send_command_packet_now()) return; 2218 2219 // handle basic actions that don't requires the full context 2220 done = sm_run_basic(); 2221 if (done) return; 2222 2223 // 2224 // active connection handling 2225 // -- use loop to handle next connection if lock on setup context is released 2226 2227 while (true) { 2228 2229 sm_run_activate_connection(); 2230 2231 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2232 2233 // 2234 // active connection handling 2235 // 2236 2237 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2238 if (!connection) { 2239 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2240 return; 2241 } 2242 2243 // assert that we could send a SM PDU - not needed for all of the following 2244 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2245 log_info("cannot send now, requesting can send now event"); 2246 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2247 return; 2248 } 2249 2250 // send keypress notifications 2251 if (setup->sm_keypress_notification){ 2252 int i; 2253 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2254 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2255 uint8_t action = 0; 2256 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2257 if (flags & (1u<<i)){ 2258 int clear_flag = 1; 2259 switch (i){ 2260 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2261 case SM_KEYPRESS_PASSKEY_CLEARED: 2262 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2263 default: 2264 break; 2265 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2266 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2267 num_actions--; 2268 clear_flag = num_actions == 0u; 2269 break; 2270 } 2271 if (clear_flag){ 2272 flags &= ~(1<<i); 2273 } 2274 action = i; 2275 break; 2276 } 2277 } 2278 setup->sm_keypress_notification = (num_actions << 5) | flags; 2279 2280 // send keypress notification 2281 uint8_t buffer[2]; 2282 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2283 buffer[1] = action; 2284 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2285 2286 // try 2287 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2288 return; 2289 } 2290 2291 int key_distribution_flags; 2292 UNUSED(key_distribution_flags); 2293 int err; 2294 UNUSED(err); 2295 2296 log_info("sm_run: state %u", connection->sm_engine_state); 2297 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2298 log_info("sm_run // cannot send"); 2299 } 2300 switch (connection->sm_engine_state){ 2301 2302 // general 2303 case SM_GENERAL_SEND_PAIRING_FAILED: { 2304 uint8_t buffer[2]; 2305 buffer[0] = SM_CODE_PAIRING_FAILED; 2306 buffer[1] = setup->sm_pairing_failed_reason; 2307 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2308 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2309 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2310 sm_done_for_handle(connection->sm_handle); 2311 break; 2312 } 2313 2314 // secure connections, initiator + responding states 2315 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2316 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2317 if (!sm_cmac_ready()) break; 2318 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2319 sm_sc_calculate_local_confirm(connection); 2320 break; 2321 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2322 if (!sm_cmac_ready()) break; 2323 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2324 sm_sc_calculate_remote_confirm(connection); 2325 break; 2326 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2327 if (!sm_cmac_ready()) break; 2328 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2329 sm_sc_calculate_f6_for_dhkey_check(connection); 2330 break; 2331 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2332 if (!sm_cmac_ready()) break; 2333 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2334 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2335 break; 2336 case SM_SC_W2_CALCULATE_F5_SALT: 2337 if (!sm_cmac_ready()) break; 2338 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2339 f5_calculate_salt(connection); 2340 break; 2341 case SM_SC_W2_CALCULATE_F5_MACKEY: 2342 if (!sm_cmac_ready()) break; 2343 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2344 f5_calculate_mackey(connection); 2345 break; 2346 case SM_SC_W2_CALCULATE_F5_LTK: 2347 if (!sm_cmac_ready()) break; 2348 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2349 f5_calculate_ltk(connection); 2350 break; 2351 case SM_SC_W2_CALCULATE_G2: 2352 if (!sm_cmac_ready()) break; 2353 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2354 g2_calculate(connection); 2355 break; 2356 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2357 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2358 if (!sm_cmac_ready()) break; 2359 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2360 h6_calculate_ilk(connection); 2361 break; 2362 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2363 if (!sm_cmac_ready()) break; 2364 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2365 h6_calculate_br_edr_link_key(connection); 2366 break; 2367 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2368 if (!sm_cmac_ready()) break; 2369 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2370 h7_calculate_ilk(connection); 2371 break; 2372 #endif 2373 #endif 2374 2375 #ifdef ENABLE_LE_CENTRAL 2376 // initiator side 2377 2378 case SM_INITIATOR_PH0_HAS_LTK: { 2379 sm_reset_setup(); 2380 sm_load_security_info(connection); 2381 2382 sm_key_t peer_ltk_flipped; 2383 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2384 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2385 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2386 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2387 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2388 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2389 return; 2390 } 2391 2392 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2393 sm_reset_setup(); 2394 sm_init_setup(connection); 2395 sm_timeout_start(connection); 2396 2397 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2398 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2399 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2400 sm_timeout_reset(connection); 2401 break; 2402 #endif 2403 2404 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2405 2406 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2407 int trigger_user_response = 0; 2408 int trigger_start_calculating_local_confirm = 0; 2409 uint8_t buffer[65]; 2410 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2411 // 2412 reverse_256(&ec_q[0], &buffer[1]); 2413 reverse_256(&ec_q[32], &buffer[33]); 2414 2415 #ifdef ENABLE_TESTING_SUPPORT 2416 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2417 log_info("testing_support: invalidating public key"); 2418 // flip single bit of public key coordinate 2419 buffer[1] ^= 1; 2420 } 2421 #endif 2422 2423 // stk generation method 2424 // passkey entry: notify app to show passkey or to request passkey 2425 switch (setup->sm_stk_generation_method){ 2426 case JUST_WORKS: 2427 case NUMERIC_COMPARISON: 2428 if (IS_RESPONDER(connection->sm_role)){ 2429 // responder 2430 trigger_start_calculating_local_confirm = 1; 2431 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2432 } else { 2433 // initiator 2434 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2435 } 2436 break; 2437 case PK_INIT_INPUT: 2438 case PK_RESP_INPUT: 2439 case PK_BOTH_INPUT: 2440 // use random TK for display 2441 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2442 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2443 setup->sm_passkey_bit = 0; 2444 2445 if (IS_RESPONDER(connection->sm_role)){ 2446 // responder 2447 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2448 } else { 2449 // initiator 2450 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2451 } 2452 trigger_user_response = 1; 2453 break; 2454 case OOB: 2455 if (IS_RESPONDER(connection->sm_role)){ 2456 // responder 2457 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2458 } else { 2459 // initiator 2460 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2461 } 2462 break; 2463 default: 2464 btstack_assert(false); 2465 break; 2466 } 2467 2468 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2469 sm_timeout_reset(connection); 2470 2471 // trigger user response and calc confirm after sending pdu 2472 if (trigger_user_response){ 2473 sm_trigger_user_response(connection); 2474 } 2475 if (trigger_start_calculating_local_confirm){ 2476 sm_sc_start_calculating_local_confirm(connection); 2477 } 2478 break; 2479 } 2480 case SM_SC_SEND_CONFIRMATION: { 2481 uint8_t buffer[17]; 2482 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2483 reverse_128(setup->sm_local_confirm, &buffer[1]); 2484 if (IS_RESPONDER(connection->sm_role)){ 2485 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2486 } else { 2487 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2488 } 2489 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2490 sm_timeout_reset(connection); 2491 break; 2492 } 2493 case SM_SC_SEND_PAIRING_RANDOM: { 2494 uint8_t buffer[17]; 2495 buffer[0] = SM_CODE_PAIRING_RANDOM; 2496 reverse_128(setup->sm_local_nonce, &buffer[1]); 2497 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2498 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2499 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2500 if (IS_RESPONDER(connection->sm_role)){ 2501 // responder 2502 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2503 } else { 2504 // initiator 2505 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2506 } 2507 } else { 2508 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2509 if (IS_RESPONDER(connection->sm_role)){ 2510 // responder 2511 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2512 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2513 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2514 } else { 2515 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2516 sm_sc_prepare_dhkey_check(connection); 2517 } 2518 } else { 2519 // initiator 2520 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2521 } 2522 } 2523 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2524 sm_timeout_reset(connection); 2525 break; 2526 } 2527 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2528 uint8_t buffer[17]; 2529 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2530 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2531 2532 if (IS_RESPONDER(connection->sm_role)){ 2533 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2534 } else { 2535 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2536 } 2537 2538 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2539 sm_timeout_reset(connection); 2540 break; 2541 } 2542 2543 #endif 2544 2545 #ifdef ENABLE_LE_PERIPHERAL 2546 2547 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2548 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2549 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2550 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2551 sm_timeout_start(connection); 2552 break; 2553 } 2554 2555 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2556 case SM_SC_RECEIVED_LTK_REQUEST: 2557 switch (connection->sm_irk_lookup_state){ 2558 case IRK_LOOKUP_SUCCEEDED: 2559 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2560 // start using context by loading security info 2561 sm_reset_setup(); 2562 sm_load_security_info(connection); 2563 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2564 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2565 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2566 sm_trigger_run(); 2567 break; 2568 } 2569 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2570 connection->sm_engine_state = SM_RESPONDER_IDLE; 2571 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2572 return; 2573 default: 2574 // just wait until IRK lookup is completed 2575 break; 2576 } 2577 break; 2578 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2579 2580 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2581 sm_reset_setup(); 2582 sm_init_setup(connection); 2583 // recover pairing request 2584 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2585 err = sm_stk_generation_init(connection); 2586 2587 #ifdef ENABLE_TESTING_SUPPORT 2588 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2589 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2590 err = test_pairing_failure; 2591 } 2592 #endif 2593 if (err){ 2594 setup->sm_pairing_failed_reason = err; 2595 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2596 sm_trigger_run(); 2597 break; 2598 } 2599 2600 sm_timeout_start(connection); 2601 2602 // generate random number first, if we need to show passkey, otherwise send response 2603 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2604 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2605 break; 2606 } 2607 2608 /* fall through */ 2609 2610 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2611 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2612 2613 // start with initiator key dist flags 2614 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2615 2616 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2617 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2618 if (setup->sm_use_secure_connections){ 2619 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2620 } 2621 #endif 2622 // setup in response 2623 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); 2624 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); 2625 2626 // update key distribution after ENC was dropped 2627 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2628 2629 if (setup->sm_use_secure_connections){ 2630 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2631 } else { 2632 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2633 } 2634 2635 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2636 sm_timeout_reset(connection); 2637 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2638 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2639 sm_trigger_user_response(connection); 2640 } 2641 return; 2642 #endif 2643 2644 case SM_PH2_SEND_PAIRING_RANDOM: { 2645 uint8_t buffer[17]; 2646 buffer[0] = SM_CODE_PAIRING_RANDOM; 2647 reverse_128(setup->sm_local_random, &buffer[1]); 2648 if (IS_RESPONDER(connection->sm_role)){ 2649 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2650 } else { 2651 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2652 } 2653 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2654 sm_timeout_reset(connection); 2655 break; 2656 } 2657 2658 case SM_PH2_C1_GET_ENC_A: 2659 // already busy? 2660 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2661 // calculate confirm using aes128 engine - step 1 2662 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); 2663 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2664 sm_aes128_state = SM_AES128_ACTIVE; 2665 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); 2666 break; 2667 2668 case SM_PH2_C1_GET_ENC_C: 2669 // already busy? 2670 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2671 // calculate m_confirm using aes128 engine - step 1 2672 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); 2673 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2674 sm_aes128_state = SM_AES128_ACTIVE; 2675 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); 2676 break; 2677 2678 case SM_PH2_CALC_STK: 2679 // already busy? 2680 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2681 // calculate STK 2682 if (IS_RESPONDER(connection->sm_role)){ 2683 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2684 } else { 2685 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2686 } 2687 connection->sm_engine_state = SM_PH2_W4_STK; 2688 sm_aes128_state = SM_AES128_ACTIVE; 2689 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); 2690 break; 2691 2692 case SM_PH3_Y_GET_ENC: 2693 // already busy? 2694 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2695 // PH3B2 - calculate Y from - enc 2696 2697 // dm helper (was sm_dm_r_prime) 2698 // r' = padding || r 2699 // r - 64 bit value 2700 memset(&sm_aes128_plaintext[0], 0, 8); 2701 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2702 2703 // Y = dm(DHK, Rand) 2704 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2705 sm_aes128_state = SM_AES128_ACTIVE; 2706 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); 2707 break; 2708 2709 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2710 uint8_t buffer[17]; 2711 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2712 reverse_128(setup->sm_local_confirm, &buffer[1]); 2713 if (IS_RESPONDER(connection->sm_role)){ 2714 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2715 } else { 2716 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2717 } 2718 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2719 sm_timeout_reset(connection); 2720 return; 2721 } 2722 #ifdef ENABLE_LE_PERIPHERAL 2723 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2724 sm_key_t stk_flipped; 2725 reverse_128(setup->sm_ltk, stk_flipped); 2726 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2727 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2728 return; 2729 } 2730 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2731 sm_key_t ltk_flipped; 2732 reverse_128(setup->sm_ltk, ltk_flipped); 2733 connection->sm_engine_state = SM_RESPONDER_IDLE; 2734 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2735 sm_done_for_handle(connection->sm_handle); 2736 return; 2737 } 2738 2739 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2740 // already busy? 2741 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2742 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2743 2744 sm_reset_setup(); 2745 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2746 2747 // dm helper (was sm_dm_r_prime) 2748 // r' = padding || r 2749 // r - 64 bit value 2750 memset(&sm_aes128_plaintext[0], 0, 8); 2751 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2752 2753 // Y = dm(DHK, Rand) 2754 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2755 sm_aes128_state = SM_AES128_ACTIVE; 2756 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); 2757 return; 2758 #endif 2759 #ifdef ENABLE_LE_CENTRAL 2760 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2761 sm_key_t stk_flipped; 2762 reverse_128(setup->sm_ltk, stk_flipped); 2763 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2764 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2765 return; 2766 } 2767 #endif 2768 2769 case SM_PH3_DISTRIBUTE_KEYS: 2770 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2771 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2772 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2773 uint8_t buffer[17]; 2774 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2775 reverse_128(setup->sm_ltk, &buffer[1]); 2776 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2777 sm_timeout_reset(connection); 2778 return; 2779 } 2780 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2781 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2782 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2783 uint8_t buffer[11]; 2784 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2785 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2786 reverse_64(setup->sm_local_rand, &buffer[3]); 2787 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2788 sm_timeout_reset(connection); 2789 return; 2790 } 2791 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2792 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2793 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2794 uint8_t buffer[17]; 2795 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2796 reverse_128(sm_persistent_irk, &buffer[1]); 2797 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2798 sm_timeout_reset(connection); 2799 return; 2800 } 2801 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2802 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2803 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2804 bd_addr_t local_address; 2805 uint8_t buffer[8]; 2806 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2807 switch (gap_random_address_get_mode()){ 2808 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2809 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2810 // public or static random 2811 gap_le_get_own_address(&buffer[1], local_address); 2812 break; 2813 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2814 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2815 // fallback to public 2816 gap_local_bd_addr(local_address); 2817 buffer[1] = 0; 2818 break; 2819 default: 2820 btstack_assert(false); 2821 break; 2822 } 2823 reverse_bd_addr(local_address, &buffer[2]); 2824 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2825 sm_timeout_reset(connection); 2826 return; 2827 } 2828 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2829 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2830 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2831 2832 #ifdef ENABLE_LE_SIGNED_WRITE 2833 // hack to reproduce test runs 2834 if (test_use_fixed_local_csrk){ 2835 memset(setup->sm_local_csrk, 0xcc, 16); 2836 } 2837 2838 // store local CSRK 2839 if (setup->sm_le_device_index >= 0){ 2840 log_info("sm: store local CSRK"); 2841 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2842 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2843 } 2844 #endif 2845 2846 uint8_t buffer[17]; 2847 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2848 reverse_128(setup->sm_local_csrk, &buffer[1]); 2849 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2850 sm_timeout_reset(connection); 2851 return; 2852 } 2853 2854 // keys are sent 2855 if (IS_RESPONDER(connection->sm_role)){ 2856 // slave -> receive master keys if any 2857 if (sm_key_distribution_all_received(connection)){ 2858 sm_key_distribution_handle_all_received(connection); 2859 connection->sm_engine_state = SM_RESPONDER_IDLE; 2860 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2861 sm_done_for_handle(connection->sm_handle); 2862 } else { 2863 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2864 } 2865 } else { 2866 sm_master_pairing_success(connection); 2867 } 2868 break; 2869 2870 default: 2871 break; 2872 } 2873 2874 // check again if active connection was released 2875 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2876 } 2877 } 2878 2879 // sm_aes128_state stays active 2880 static void sm_handle_encryption_result_enc_a(void *arg){ 2881 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2882 sm_aes128_state = SM_AES128_IDLE; 2883 2884 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2885 if (connection == NULL) return; 2886 2887 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2888 sm_aes128_state = SM_AES128_ACTIVE; 2889 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); 2890 } 2891 2892 static void sm_handle_encryption_result_enc_b(void *arg){ 2893 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2894 sm_aes128_state = SM_AES128_IDLE; 2895 2896 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2897 if (connection == NULL) return; 2898 2899 log_info_key("c1!", setup->sm_local_confirm); 2900 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2901 sm_trigger_run(); 2902 } 2903 2904 // sm_aes128_state stays active 2905 static void sm_handle_encryption_result_enc_c(void *arg){ 2906 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2907 sm_aes128_state = SM_AES128_IDLE; 2908 2909 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2910 if (connection == NULL) return; 2911 2912 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2913 sm_aes128_state = SM_AES128_ACTIVE; 2914 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); 2915 } 2916 2917 static void sm_handle_encryption_result_enc_d(void * arg){ 2918 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2919 sm_aes128_state = SM_AES128_IDLE; 2920 2921 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2922 if (connection == NULL) return; 2923 2924 log_info_key("c1!", sm_aes128_ciphertext); 2925 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2926 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2927 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2928 sm_trigger_run(); 2929 return; 2930 } 2931 if (IS_RESPONDER(connection->sm_role)){ 2932 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2933 sm_trigger_run(); 2934 } else { 2935 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2936 sm_aes128_state = SM_AES128_ACTIVE; 2937 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); 2938 } 2939 } 2940 2941 static void sm_handle_encryption_result_enc_stk(void *arg){ 2942 sm_aes128_state = SM_AES128_IDLE; 2943 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2944 2945 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2946 if (connection == NULL) return; 2947 2948 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2949 log_info_key("stk", setup->sm_ltk); 2950 if (IS_RESPONDER(connection->sm_role)){ 2951 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2952 } else { 2953 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2954 } 2955 sm_trigger_run(); 2956 } 2957 2958 // sm_aes128_state stays active 2959 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2960 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2961 sm_aes128_state = SM_AES128_IDLE; 2962 2963 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2964 if (connection == NULL) return; 2965 2966 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2967 log_info_hex16("y", setup->sm_local_y); 2968 // PH3B3 - calculate EDIV 2969 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2970 log_info_hex16("ediv", setup->sm_local_ediv); 2971 // PH3B4 - calculate LTK - enc 2972 // LTK = d1(ER, DIV, 0)) 2973 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2974 sm_aes128_state = SM_AES128_ACTIVE; 2975 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); 2976 } 2977 2978 #ifdef ENABLE_LE_PERIPHERAL 2979 // sm_aes128_state stays active 2980 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2981 sm_aes128_state = SM_AES128_IDLE; 2982 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2983 2984 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2985 if (connection == NULL) return; 2986 2987 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2988 log_info_hex16("y", setup->sm_local_y); 2989 2990 // PH3B3 - calculate DIV 2991 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2992 log_info_hex16("ediv", setup->sm_local_ediv); 2993 // PH3B4 - calculate LTK - enc 2994 // LTK = d1(ER, DIV, 0)) 2995 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2996 sm_aes128_state = SM_AES128_ACTIVE; 2997 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); 2998 } 2999 #endif 3000 3001 // sm_aes128_state stays active 3002 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3003 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3004 sm_aes128_state = SM_AES128_IDLE; 3005 3006 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3007 if (connection == NULL) return; 3008 3009 log_info_key("ltk", setup->sm_ltk); 3010 // calc CSRK next 3011 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3012 sm_aes128_state = SM_AES128_ACTIVE; 3013 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); 3014 } 3015 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3016 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3017 // requirements to derive link key from LE: 3018 // - use secure connections 3019 if (setup->sm_use_secure_connections == 0) return false; 3020 // - bonding needs to be enabled: 3021 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; 3022 if (!bonding_enabled) return false; 3023 // - need identity address 3024 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3025 if (!have_identity_address_info) return false; 3026 // - 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) 3027 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3028 // If SC is authenticated, we consider it safe to overwrite a stored key. 3029 // 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. 3030 uint8_t link_key[16]; 3031 link_key_type_t link_key_type; 3032 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3033 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3034 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3035 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3036 return false; 3037 } 3038 // get started (all of the above are true) 3039 return true; 3040 #else 3041 UNUSED(sm_connection); 3042 return false; 3043 #endif 3044 } 3045 3046 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3047 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3048 sm_aes128_state = SM_AES128_IDLE; 3049 3050 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3051 if (connection == NULL) return; 3052 3053 sm_aes128_state = SM_AES128_IDLE; 3054 log_info_key("csrk", setup->sm_local_csrk); 3055 if (setup->sm_key_distribution_send_set){ 3056 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3057 } else { 3058 // no keys to send, just continue 3059 if (IS_RESPONDER(connection->sm_role)){ 3060 // slave -> receive master keys 3061 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3062 } else { 3063 if (sm_ctkd_from_le(connection)){ 3064 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; 3065 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3066 } else { 3067 sm_master_pairing_success(connection); 3068 } 3069 } 3070 } 3071 sm_trigger_run(); 3072 } 3073 3074 #ifdef ENABLE_LE_PERIPHERAL 3075 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3076 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3077 sm_aes128_state = SM_AES128_IDLE; 3078 3079 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3080 if (connection == NULL) return; 3081 3082 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3083 log_info_key("ltk", setup->sm_ltk); 3084 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3085 sm_trigger_run(); 3086 } 3087 #endif 3088 3089 static void sm_handle_encryption_result_address_resolution(void *arg){ 3090 UNUSED(arg); 3091 sm_aes128_state = SM_AES128_IDLE; 3092 3093 sm_address_resolution_ah_calculation_active = 0; 3094 // compare calulated address against connecting device 3095 uint8_t * hash = &sm_aes128_ciphertext[13]; 3096 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3097 log_info("LE Device Lookup: matched resolvable private address"); 3098 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3099 sm_trigger_run(); 3100 return; 3101 } 3102 // no match, try next 3103 sm_address_resolution_test++; 3104 sm_trigger_run(); 3105 } 3106 3107 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3108 UNUSED(arg); 3109 sm_aes128_state = SM_AES128_IDLE; 3110 3111 log_info_key("irk", sm_persistent_irk); 3112 dkg_state = DKG_CALC_DHK; 3113 sm_trigger_run(); 3114 } 3115 3116 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3117 UNUSED(arg); 3118 sm_aes128_state = SM_AES128_IDLE; 3119 3120 log_info_key("dhk", sm_persistent_dhk); 3121 dkg_state = DKG_READY; 3122 sm_trigger_run(); 3123 } 3124 3125 static void sm_handle_encryption_result_rau(void *arg){ 3126 UNUSED(arg); 3127 sm_aes128_state = SM_AES128_IDLE; 3128 3129 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3130 rau_state = RAU_SET_ADDRESS; 3131 sm_trigger_run(); 3132 } 3133 3134 static void sm_handle_random_result_rau(void * arg){ 3135 UNUSED(arg); 3136 // non-resolvable vs. resolvable 3137 switch (gap_random_adress_type){ 3138 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3139 // resolvable: use random as prand and calc address hash 3140 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3141 sm_random_address[0u] &= 0x3fu; 3142 sm_random_address[0u] |= 0x40u; 3143 rau_state = RAU_GET_ENC; 3144 break; 3145 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3146 default: 3147 // "The two most significant bits of the address shall be equal to ‘0’"" 3148 sm_random_address[0u] &= 0x3fu; 3149 rau_state = RAU_SET_ADDRESS; 3150 break; 3151 } 3152 sm_trigger_run(); 3153 } 3154 3155 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3156 static void sm_handle_random_result_sc_next_send_pairing_random(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_SEND_PAIRING_RANDOM; 3162 sm_trigger_run(); 3163 } 3164 3165 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3166 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3167 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3168 if (connection == NULL) return; 3169 3170 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3171 sm_trigger_run(); 3172 } 3173 #endif 3174 3175 static void sm_handle_random_result_ph2_random(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 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3181 sm_trigger_run(); 3182 } 3183 3184 static void sm_handle_random_result_ph2_tk(void * arg){ 3185 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3186 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3187 if (connection == NULL) return; 3188 3189 sm_reset_tk(); 3190 uint32_t tk; 3191 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3192 // map random to 0-999999 without speding much cycles on a modulus operation 3193 tk = little_endian_read_32(sm_random_data,0); 3194 tk = tk & 0xfffff; // 1048575 3195 if (tk >= 999999u){ 3196 tk = tk - 999999u; 3197 } 3198 } else { 3199 // override with pre-defined passkey 3200 tk = sm_fixed_passkey_in_display_role; 3201 } 3202 big_endian_store_32(setup->sm_tk, 12, tk); 3203 if (IS_RESPONDER(connection->sm_role)){ 3204 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3205 } else { 3206 if (setup->sm_use_secure_connections){ 3207 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3208 } else { 3209 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3210 sm_trigger_user_response(connection); 3211 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3212 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3213 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); 3214 } 3215 } 3216 } 3217 sm_trigger_run(); 3218 } 3219 3220 static void sm_handle_random_result_ph3_div(void * arg){ 3221 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3222 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3223 if (connection == NULL) return; 3224 3225 // use 16 bit from random value as div 3226 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3227 log_info_hex16("div", setup->sm_local_div); 3228 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3229 sm_trigger_run(); 3230 } 3231 3232 static void sm_handle_random_result_ph3_random(void * arg){ 3233 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3234 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3235 if (connection == NULL) return; 3236 3237 reverse_64(sm_random_data, setup->sm_local_rand); 3238 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3239 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3240 // no db for authenticated flag hack: store flag in bit 4 of LSB 3241 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3242 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3243 } 3244 static void sm_validate_er_ir(void){ 3245 // warn about default ER/IR 3246 int warning = 0; 3247 if (sm_ir_is_default()){ 3248 warning = 1; 3249 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3250 } 3251 if (sm_er_is_default()){ 3252 warning = 1; 3253 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3254 } 3255 if (warning) { 3256 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3257 } 3258 } 3259 3260 static void sm_handle_random_result_ir(void *arg){ 3261 sm_persistent_keys_random_active = 0; 3262 if (arg){ 3263 // key generated, store in tlv 3264 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3265 log_info("Generated IR key. Store in TLV status: %d", status); 3266 UNUSED(status); 3267 } 3268 log_info_key("IR", sm_persistent_ir); 3269 dkg_state = DKG_CALC_IRK; 3270 3271 if (test_use_fixed_local_irk){ 3272 log_info_key("IRK", sm_persistent_irk); 3273 dkg_state = DKG_CALC_DHK; 3274 } 3275 3276 sm_trigger_run(); 3277 } 3278 3279 static void sm_handle_random_result_er(void *arg){ 3280 sm_persistent_keys_random_active = 0; 3281 if (arg){ 3282 // key generated, store in tlv 3283 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3284 log_info("Generated ER key. Store in TLV status: %d", status); 3285 UNUSED(status); 3286 } 3287 log_info_key("ER", sm_persistent_er); 3288 3289 // try load ir 3290 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3291 if (key_size == 16){ 3292 // ok, let's continue 3293 log_info("IR from TLV"); 3294 sm_handle_random_result_ir( NULL ); 3295 } else { 3296 // invalid, generate new random one 3297 sm_persistent_keys_random_active = 1; 3298 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3299 } 3300 } 3301 3302 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3303 3304 UNUSED(channel); // ok: there is no channel 3305 UNUSED(size); // ok: fixed format HCI events 3306 3307 sm_connection_t * sm_conn; 3308 hci_con_handle_t con_handle; 3309 uint8_t status; 3310 switch (packet_type) { 3311 3312 case HCI_EVENT_PACKET: 3313 switch (hci_event_packet_get_type(packet)) { 3314 3315 case BTSTACK_EVENT_STATE: 3316 // bt stack activated, get started 3317 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3318 log_info("HCI Working!"); 3319 3320 // setup IR/ER with TLV 3321 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3322 if (sm_tlv_impl){ 3323 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3324 if (key_size == 16){ 3325 // ok, let's continue 3326 log_info("ER from TLV"); 3327 sm_handle_random_result_er( NULL ); 3328 } else { 3329 // invalid, generate random one 3330 sm_persistent_keys_random_active = 1; 3331 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3332 } 3333 } else { 3334 sm_validate_er_ir(); 3335 dkg_state = DKG_CALC_IRK; 3336 3337 if (test_use_fixed_local_irk){ 3338 log_info_key("IRK", sm_persistent_irk); 3339 dkg_state = DKG_CALC_DHK; 3340 } 3341 } 3342 3343 // restart random address updates after power cycle 3344 gap_random_address_set_mode(gap_random_adress_type); 3345 } 3346 break; 3347 3348 case HCI_EVENT_LE_META: 3349 switch (packet[2]) { 3350 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3351 3352 log_info("sm: connected"); 3353 3354 if (packet[3]) return; // connection failed 3355 3356 con_handle = little_endian_read_16(packet, 4); 3357 sm_conn = sm_get_connection_for_handle(con_handle); 3358 if (!sm_conn) break; 3359 3360 sm_conn->sm_handle = con_handle; 3361 sm_conn->sm_role = packet[6]; 3362 sm_conn->sm_peer_addr_type = packet[7]; 3363 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3364 3365 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3366 3367 // reset security properties 3368 sm_conn->sm_connection_encrypted = 0; 3369 sm_conn->sm_connection_authenticated = 0; 3370 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3371 sm_conn->sm_le_db_index = -1; 3372 3373 // prepare CSRK lookup (does not involve setup) 3374 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3375 3376 // just connected -> everything else happens in sm_run() 3377 if (IS_RESPONDER(sm_conn->sm_role)){ 3378 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3379 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3380 if (sm_slave_request_security) { 3381 // request security if requested by app 3382 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3383 } else { 3384 // otherwise, wait for pairing request 3385 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3386 } 3387 } 3388 break; 3389 } else { 3390 // master 3391 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3392 } 3393 break; 3394 3395 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3396 con_handle = little_endian_read_16(packet, 3); 3397 sm_conn = sm_get_connection_for_handle(con_handle); 3398 if (!sm_conn) break; 3399 3400 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3401 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3402 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3403 break; 3404 } 3405 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3406 // PH2 SEND LTK as we need to exchange keys in PH3 3407 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3408 break; 3409 } 3410 3411 // store rand and ediv 3412 reverse_64(&packet[5], sm_conn->sm_local_rand); 3413 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3414 3415 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3416 // potentially stored LTK is from the master 3417 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3418 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3419 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3420 break; 3421 } 3422 // additionally check if remote is in LE Device DB if requested 3423 switch(sm_conn->sm_irk_lookup_state){ 3424 case IRK_LOOKUP_FAILED: 3425 log_info("LTK Request: device not in device db"); 3426 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3427 break; 3428 case IRK_LOOKUP_SUCCEEDED: 3429 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3430 break; 3431 default: 3432 // wait for irk look doen 3433 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3434 break; 3435 } 3436 break; 3437 } 3438 3439 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3440 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3441 #else 3442 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3443 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3444 #endif 3445 break; 3446 3447 default: 3448 break; 3449 } 3450 break; 3451 3452 case HCI_EVENT_ENCRYPTION_CHANGE: 3453 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3454 sm_conn = sm_get_connection_for_handle(con_handle); 3455 if (!sm_conn) break; 3456 3457 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3458 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3459 sm_conn->sm_actual_encryption_key_size); 3460 log_info("event handler, state %u", sm_conn->sm_engine_state); 3461 3462 switch (sm_conn->sm_engine_state){ 3463 3464 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3465 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3466 if (sm_conn->sm_connection_encrypted) { 3467 status = ERROR_CODE_SUCCESS; 3468 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3469 } else { 3470 status = ERROR_CODE_AUTHENTICATION_FAILURE; 3471 // set state to 'TIMEOUT' to prevent further interaction with this 3472 // also, gap_reconnect_security_setup_active will return true 3473 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 3474 } 3475 3476 // emit re-encryption complete 3477 sm_notify_client_reencryption_complete(sm_conn, status); 3478 3479 // notify client, if pairing was requested before 3480 if (sm_conn->sm_pairing_requested){ 3481 sm_conn->sm_pairing_requested = 0; 3482 sm_notify_client_status_reason(sm_conn, status, 0); 3483 } 3484 3485 sm_done_for_handle(sm_conn->sm_handle); 3486 3487 // abort/disconnect on authentication failure 3488 if (status == ERROR_CODE_AUTHENTICATION_FAILURE){ 3489 // gap disconnect with authentication failure 3490 hci_disconnect_security_block(con_handle); 3491 } 3492 break; 3493 3494 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3495 if (!sm_conn->sm_connection_encrypted) break; 3496 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3497 if (IS_RESPONDER(sm_conn->sm_role)){ 3498 // slave 3499 if (setup->sm_use_secure_connections){ 3500 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3501 } else { 3502 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); 3503 } 3504 } else { 3505 // master 3506 if (sm_key_distribution_all_received(sm_conn)){ 3507 // skip receiving keys as there are none 3508 sm_key_distribution_handle_all_received(sm_conn); 3509 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); 3510 } else { 3511 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3512 } 3513 } 3514 break; 3515 default: 3516 break; 3517 } 3518 break; 3519 3520 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3521 con_handle = little_endian_read_16(packet, 3); 3522 sm_conn = sm_get_connection_for_handle(con_handle); 3523 if (!sm_conn) break; 3524 3525 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3526 log_info("event handler, state %u", sm_conn->sm_engine_state); 3527 // continue if part of initial pairing 3528 switch (sm_conn->sm_engine_state){ 3529 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3530 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3531 sm_done_for_handle(sm_conn->sm_handle); 3532 break; 3533 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3534 if (IS_RESPONDER(sm_conn->sm_role)){ 3535 // slave 3536 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); 3537 } else { 3538 // master 3539 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3540 } 3541 break; 3542 default: 3543 break; 3544 } 3545 break; 3546 3547 3548 case HCI_EVENT_DISCONNECTION_COMPLETE: 3549 con_handle = little_endian_read_16(packet, 3); 3550 sm_done_for_handle(con_handle); 3551 sm_conn = sm_get_connection_for_handle(con_handle); 3552 if (!sm_conn) break; 3553 3554 // delete stored bonding on disconnect with authentication failure in ph0 3555 if ((sm_conn->sm_role == 0u) 3556 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3557 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3558 le_device_db_remove(sm_conn->sm_le_db_index); 3559 } 3560 3561 // pairing failed, if it was ongoing 3562 switch (sm_conn->sm_engine_state){ 3563 case SM_GENERAL_IDLE: 3564 case SM_INITIATOR_CONNECTED: 3565 case SM_RESPONDER_IDLE: 3566 break; 3567 default: 3568 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3569 break; 3570 } 3571 3572 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3573 sm_conn->sm_handle = 0; 3574 break; 3575 3576 case HCI_EVENT_COMMAND_COMPLETE: 3577 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3578 // set local addr for le device db 3579 bd_addr_t addr; 3580 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3581 le_device_db_set_local_bd_addr(addr); 3582 } 3583 break; 3584 default: 3585 break; 3586 } 3587 break; 3588 default: 3589 break; 3590 } 3591 3592 sm_run(); 3593 } 3594 3595 static inline int sm_calc_actual_encryption_key_size(int other){ 3596 if (other < sm_min_encryption_key_size) return 0; 3597 if (other < sm_max_encryption_key_size) return other; 3598 return sm_max_encryption_key_size; 3599 } 3600 3601 3602 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3603 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3604 switch (method){ 3605 case JUST_WORKS: 3606 case NUMERIC_COMPARISON: 3607 return 1; 3608 default: 3609 return 0; 3610 } 3611 } 3612 // responder 3613 3614 static int sm_passkey_used(stk_generation_method_t method){ 3615 switch (method){ 3616 case PK_RESP_INPUT: 3617 return 1; 3618 default: 3619 return 0; 3620 } 3621 } 3622 3623 static int sm_passkey_entry(stk_generation_method_t method){ 3624 switch (method){ 3625 case PK_RESP_INPUT: 3626 case PK_INIT_INPUT: 3627 case PK_BOTH_INPUT: 3628 return 1; 3629 default: 3630 return 0; 3631 } 3632 } 3633 3634 #endif 3635 3636 /** 3637 * @return ok 3638 */ 3639 static int sm_validate_stk_generation_method(void){ 3640 // check if STK generation method is acceptable by client 3641 switch (setup->sm_stk_generation_method){ 3642 case JUST_WORKS: 3643 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3644 case PK_RESP_INPUT: 3645 case PK_INIT_INPUT: 3646 case PK_BOTH_INPUT: 3647 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3648 case OOB: 3649 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3650 case NUMERIC_COMPARISON: 3651 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3652 default: 3653 return 0; 3654 } 3655 } 3656 3657 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3658 3659 // size of complete sm_pdu used to validate input 3660 static const uint8_t sm_pdu_size[] = { 3661 0, // 0x00 invalid opcode 3662 7, // 0x01 pairing request 3663 7, // 0x02 pairing response 3664 17, // 0x03 pairing confirm 3665 17, // 0x04 pairing random 3666 2, // 0x05 pairing failed 3667 17, // 0x06 encryption information 3668 11, // 0x07 master identification 3669 17, // 0x08 identification information 3670 8, // 0x09 identify address information 3671 17, // 0x0a signing information 3672 2, // 0x0b security request 3673 65, // 0x0c pairing public key 3674 17, // 0x0d pairing dhk check 3675 2, // 0x0e keypress notification 3676 }; 3677 3678 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3679 sm_run(); 3680 } 3681 3682 if (packet_type != SM_DATA_PACKET) return; 3683 if (size == 0u) return; 3684 3685 uint8_t sm_pdu_code = packet[0]; 3686 3687 // validate pdu size 3688 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3689 if (sm_pdu_size[sm_pdu_code] != size) return; 3690 3691 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3692 if (!sm_conn) return; 3693 3694 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3695 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3696 sm_done_for_handle(con_handle); 3697 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3698 return; 3699 } 3700 3701 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3702 3703 int err; 3704 UNUSED(err); 3705 3706 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3707 uint8_t buffer[5]; 3708 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3709 buffer[1] = 3; 3710 little_endian_store_16(buffer, 2, con_handle); 3711 buffer[4] = packet[1]; 3712 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3713 return; 3714 } 3715 3716 switch (sm_conn->sm_engine_state){ 3717 3718 // a sm timeout requires a new physical connection 3719 case SM_GENERAL_TIMEOUT: 3720 return; 3721 3722 #ifdef ENABLE_LE_CENTRAL 3723 3724 // Initiator 3725 case SM_INITIATOR_CONNECTED: 3726 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3727 sm_pdu_received_in_wrong_state(sm_conn); 3728 break; 3729 } 3730 3731 // IRK complete? 3732 int have_ltk; 3733 uint8_t ltk[16]; 3734 switch (sm_conn->sm_irk_lookup_state){ 3735 case IRK_LOOKUP_FAILED: 3736 // start pairing 3737 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3738 break; 3739 case IRK_LOOKUP_SUCCEEDED: 3740 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3741 have_ltk = !sm_is_null_key(ltk); 3742 log_info("central: security request - have_ltk %u", have_ltk); 3743 if (have_ltk){ 3744 // start re-encrypt 3745 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3746 } else { 3747 // start pairing 3748 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3749 } 3750 break; 3751 default: 3752 // otherwise, store security request 3753 sm_conn->sm_security_request_received = 1; 3754 break; 3755 } 3756 break; 3757 3758 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3759 // Core 5, Vol 3, Part H, 2.4.6: 3760 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3761 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3762 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3763 log_info("Ignoring Security Request"); 3764 break; 3765 } 3766 3767 // all other pdus are incorrect 3768 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3769 sm_pdu_received_in_wrong_state(sm_conn); 3770 break; 3771 } 3772 3773 // store pairing request 3774 (void)memcpy(&setup->sm_s_pres, packet, 3775 sizeof(sm_pairing_packet_t)); 3776 err = sm_stk_generation_init(sm_conn); 3777 3778 #ifdef ENABLE_TESTING_SUPPORT 3779 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3780 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3781 err = test_pairing_failure; 3782 } 3783 #endif 3784 3785 if (err){ 3786 setup->sm_pairing_failed_reason = err; 3787 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3788 break; 3789 } 3790 3791 // generate random number first, if we need to show passkey 3792 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3793 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); 3794 break; 3795 } 3796 3797 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3798 if (setup->sm_use_secure_connections){ 3799 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3800 if (setup->sm_stk_generation_method == JUST_WORKS){ 3801 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3802 sm_trigger_user_response(sm_conn); 3803 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3804 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3805 } 3806 } else { 3807 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3808 } 3809 break; 3810 } 3811 #endif 3812 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3813 sm_trigger_user_response(sm_conn); 3814 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3815 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3816 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); 3817 } 3818 break; 3819 3820 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3821 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3822 sm_pdu_received_in_wrong_state(sm_conn); 3823 break; 3824 } 3825 3826 // store s_confirm 3827 reverse_128(&packet[1], setup->sm_peer_confirm); 3828 3829 #ifdef ENABLE_TESTING_SUPPORT 3830 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3831 log_info("testing_support: reset confirm value"); 3832 memset(setup->sm_peer_confirm, 0, 16); 3833 } 3834 #endif 3835 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3836 break; 3837 3838 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3839 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3840 sm_pdu_received_in_wrong_state(sm_conn); 3841 break;; 3842 } 3843 3844 // received random value 3845 reverse_128(&packet[1], setup->sm_peer_random); 3846 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3847 break; 3848 #endif 3849 3850 #ifdef ENABLE_LE_PERIPHERAL 3851 // Responder 3852 case SM_RESPONDER_IDLE: 3853 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3854 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3855 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3856 sm_pdu_received_in_wrong_state(sm_conn); 3857 break;; 3858 } 3859 3860 // store pairing request 3861 (void)memcpy(&sm_conn->sm_m_preq, packet, 3862 sizeof(sm_pairing_packet_t)); 3863 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3864 break; 3865 #endif 3866 3867 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3868 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3869 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3870 sm_pdu_received_in_wrong_state(sm_conn); 3871 break; 3872 } 3873 3874 // store public key for DH Key calculation 3875 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3876 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3877 3878 // validate public key 3879 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3880 if (err){ 3881 log_error("sm: peer public key invalid %x", err); 3882 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3883 break; 3884 } 3885 3886 // start calculating dhkey 3887 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); 3888 3889 3890 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3891 if (IS_RESPONDER(sm_conn->sm_role)){ 3892 // responder 3893 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3894 } else { 3895 // initiator 3896 // stk generation method 3897 // passkey entry: notify app to show passkey or to request passkey 3898 switch (setup->sm_stk_generation_method){ 3899 case JUST_WORKS: 3900 case NUMERIC_COMPARISON: 3901 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3902 break; 3903 case PK_RESP_INPUT: 3904 sm_sc_start_calculating_local_confirm(sm_conn); 3905 break; 3906 case PK_INIT_INPUT: 3907 case PK_BOTH_INPUT: 3908 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3909 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3910 break; 3911 } 3912 sm_sc_start_calculating_local_confirm(sm_conn); 3913 break; 3914 case OOB: 3915 // generate Nx 3916 log_info("Generate Na"); 3917 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); 3918 break; 3919 default: 3920 btstack_assert(false); 3921 break; 3922 } 3923 } 3924 break; 3925 3926 case SM_SC_W4_CONFIRMATION: 3927 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3928 sm_pdu_received_in_wrong_state(sm_conn); 3929 break; 3930 } 3931 // received confirm value 3932 reverse_128(&packet[1], setup->sm_peer_confirm); 3933 3934 #ifdef ENABLE_TESTING_SUPPORT 3935 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3936 log_info("testing_support: reset confirm value"); 3937 memset(setup->sm_peer_confirm, 0, 16); 3938 } 3939 #endif 3940 if (IS_RESPONDER(sm_conn->sm_role)){ 3941 // responder 3942 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3943 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3944 // still waiting for passkey 3945 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3946 break; 3947 } 3948 } 3949 sm_sc_start_calculating_local_confirm(sm_conn); 3950 } else { 3951 // initiator 3952 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3953 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); 3954 } else { 3955 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3956 } 3957 } 3958 break; 3959 3960 case SM_SC_W4_PAIRING_RANDOM: 3961 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3962 sm_pdu_received_in_wrong_state(sm_conn); 3963 break; 3964 } 3965 3966 // received random value 3967 reverse_128(&packet[1], setup->sm_peer_nonce); 3968 3969 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3970 // only check for JUST WORK/NC in initiator role OR passkey entry 3971 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 3972 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 3973 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 3974 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3975 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 3976 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3977 break; 3978 } 3979 3980 // OOB 3981 if (setup->sm_stk_generation_method == OOB){ 3982 3983 // setup local random, set to zero if remote did not receive our data 3984 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3985 if (IS_RESPONDER(sm_conn->sm_role)){ 3986 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 3987 log_info("Reset rb as A does not have OOB data"); 3988 memset(setup->sm_rb, 0, 16); 3989 } else { 3990 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3991 log_info("Use stored rb"); 3992 log_info_hexdump(setup->sm_rb, 16); 3993 } 3994 } else { 3995 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 3996 log_info("Reset ra as B does not have OOB data"); 3997 memset(setup->sm_ra, 0, 16); 3998 } else { 3999 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4000 log_info("Use stored ra"); 4001 log_info_hexdump(setup->sm_ra, 16); 4002 } 4003 } 4004 4005 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4006 if (setup->sm_have_oob_data){ 4007 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4008 break; 4009 } 4010 } 4011 4012 // TODO: we only get here for Responder role with JW/NC 4013 sm_sc_state_after_receiving_random(sm_conn); 4014 break; 4015 4016 case SM_SC_W2_CALCULATE_G2: 4017 case SM_SC_W4_CALCULATE_G2: 4018 case SM_SC_W4_CALCULATE_DHKEY: 4019 case SM_SC_W2_CALCULATE_F5_SALT: 4020 case SM_SC_W4_CALCULATE_F5_SALT: 4021 case SM_SC_W2_CALCULATE_F5_MACKEY: 4022 case SM_SC_W4_CALCULATE_F5_MACKEY: 4023 case SM_SC_W2_CALCULATE_F5_LTK: 4024 case SM_SC_W4_CALCULATE_F5_LTK: 4025 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4026 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4027 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4028 case SM_SC_W4_USER_RESPONSE: 4029 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4030 sm_pdu_received_in_wrong_state(sm_conn); 4031 break; 4032 } 4033 // store DHKey Check 4034 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4035 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4036 4037 // have we been only waiting for dhkey check command? 4038 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4039 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4040 } 4041 break; 4042 #endif 4043 4044 #ifdef ENABLE_LE_PERIPHERAL 4045 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4046 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4047 sm_pdu_received_in_wrong_state(sm_conn); 4048 break; 4049 } 4050 4051 // received confirm value 4052 reverse_128(&packet[1], setup->sm_peer_confirm); 4053 4054 #ifdef ENABLE_TESTING_SUPPORT 4055 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4056 log_info("testing_support: reset confirm value"); 4057 memset(setup->sm_peer_confirm, 0, 16); 4058 } 4059 #endif 4060 // notify client to hide shown passkey 4061 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4062 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4063 } 4064 4065 // handle user cancel pairing? 4066 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4067 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4068 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4069 break; 4070 } 4071 4072 // wait for user action? 4073 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4074 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4075 break; 4076 } 4077 4078 // calculate and send local_confirm 4079 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); 4080 break; 4081 4082 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4083 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4084 sm_pdu_received_in_wrong_state(sm_conn); 4085 break;; 4086 } 4087 4088 // received random value 4089 reverse_128(&packet[1], setup->sm_peer_random); 4090 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4091 break; 4092 #endif 4093 4094 case SM_PH3_RECEIVE_KEYS: 4095 switch(sm_pdu_code){ 4096 case SM_CODE_ENCRYPTION_INFORMATION: 4097 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4098 reverse_128(&packet[1], setup->sm_peer_ltk); 4099 break; 4100 4101 case SM_CODE_MASTER_IDENTIFICATION: 4102 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4103 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4104 reverse_64(&packet[3], setup->sm_peer_rand); 4105 break; 4106 4107 case SM_CODE_IDENTITY_INFORMATION: 4108 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4109 reverse_128(&packet[1], setup->sm_peer_irk); 4110 break; 4111 4112 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4113 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4114 setup->sm_peer_addr_type = packet[1]; 4115 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4116 break; 4117 4118 case SM_CODE_SIGNING_INFORMATION: 4119 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4120 reverse_128(&packet[1], setup->sm_peer_csrk); 4121 break; 4122 default: 4123 // Unexpected PDU 4124 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4125 break; 4126 } 4127 // done with key distribution? 4128 if (sm_key_distribution_all_received(sm_conn)){ 4129 4130 sm_key_distribution_handle_all_received(sm_conn); 4131 4132 if (IS_RESPONDER(sm_conn->sm_role)){ 4133 if (sm_ctkd_from_le(sm_conn)){ 4134 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; 4135 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4136 } else { 4137 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4138 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 4139 sm_done_for_handle(sm_conn->sm_handle); 4140 } 4141 } else { 4142 if (setup->sm_use_secure_connections){ 4143 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4144 } else { 4145 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); 4146 } 4147 } 4148 } 4149 break; 4150 default: 4151 // Unexpected PDU 4152 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4153 break; 4154 } 4155 4156 // try to send next pdu 4157 sm_trigger_run(); 4158 } 4159 4160 // Security Manager Client API 4161 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4162 sm_get_oob_data = get_oob_data_callback; 4163 } 4164 4165 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)){ 4166 sm_get_sc_oob_data = get_sc_oob_data_callback; 4167 } 4168 4169 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4170 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4171 } 4172 4173 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4174 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4175 } 4176 4177 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4178 sm_min_encryption_key_size = min_size; 4179 sm_max_encryption_key_size = max_size; 4180 } 4181 4182 void sm_set_authentication_requirements(uint8_t auth_req){ 4183 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4184 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4185 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4186 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4187 } 4188 #endif 4189 sm_auth_req = auth_req; 4190 } 4191 4192 void sm_set_io_capabilities(io_capability_t io_capability){ 4193 sm_io_capabilities = io_capability; 4194 } 4195 4196 #ifdef ENABLE_LE_PERIPHERAL 4197 void sm_set_request_security(int enable){ 4198 sm_slave_request_security = enable; 4199 } 4200 #endif 4201 4202 void sm_set_er(sm_key_t er){ 4203 (void)memcpy(sm_persistent_er, er, 16); 4204 } 4205 4206 void sm_set_ir(sm_key_t ir){ 4207 (void)memcpy(sm_persistent_ir, ir, 16); 4208 } 4209 4210 // Testing support only 4211 void sm_test_set_irk(sm_key_t irk){ 4212 (void)memcpy(sm_persistent_irk, irk, 16); 4213 dkg_state = DKG_CALC_DHK; 4214 test_use_fixed_local_irk = true; 4215 } 4216 4217 void sm_test_use_fixed_local_csrk(void){ 4218 test_use_fixed_local_csrk = true; 4219 } 4220 4221 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4222 static void sm_ec_generated(void * arg){ 4223 UNUSED(arg); 4224 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4225 // trigger pairing if pending for ec key 4226 sm_trigger_run(); 4227 } 4228 static void sm_ec_generate_new_key(void){ 4229 log_info("sm: generate new ec key"); 4230 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4231 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4232 } 4233 #endif 4234 4235 #ifdef ENABLE_TESTING_SUPPORT 4236 void sm_test_set_pairing_failure(int reason){ 4237 test_pairing_failure = reason; 4238 } 4239 #endif 4240 4241 void sm_init(void){ 4242 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4243 sm_er_ir_set_default(); 4244 4245 // defaults 4246 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4247 | SM_STK_GENERATION_METHOD_OOB 4248 | SM_STK_GENERATION_METHOD_PASSKEY 4249 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4250 4251 sm_max_encryption_key_size = 16; 4252 sm_min_encryption_key_size = 7; 4253 4254 sm_fixed_passkey_in_display_role = 0xffffffff; 4255 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4256 4257 #ifdef USE_CMAC_ENGINE 4258 sm_cmac_active = 0; 4259 #endif 4260 dkg_state = DKG_W4_WORKING; 4261 rau_state = RAU_IDLE; 4262 sm_aes128_state = SM_AES128_IDLE; 4263 sm_address_resolution_test = -1; // no private address to resolve yet 4264 sm_address_resolution_ah_calculation_active = 0; 4265 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4266 sm_address_resolution_general_queue = NULL; 4267 4268 gap_random_adress_update_period = 15 * 60 * 1000L; 4269 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4270 4271 test_use_fixed_local_csrk = false; 4272 4273 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4274 4275 // register for HCI Events from HCI 4276 hci_event_callback_registration.callback = &sm_event_packet_handler; 4277 hci_add_event_handler(&hci_event_callback_registration); 4278 4279 // 4280 btstack_crypto_init(); 4281 4282 // init le_device_db 4283 le_device_db_init(); 4284 4285 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4286 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4287 4288 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4289 sm_ec_generate_new_key(); 4290 #endif 4291 } 4292 4293 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4294 sm_fixed_passkey_in_display_role = passkey; 4295 } 4296 4297 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4298 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4299 } 4300 4301 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4302 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4303 if (!hci_con) return NULL; 4304 return &hci_con->sm_connection; 4305 } 4306 4307 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4308 switch (sm_conn->sm_engine_state){ 4309 case SM_GENERAL_IDLE: 4310 case SM_RESPONDER_IDLE: 4311 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4312 sm_trigger_run(); 4313 break; 4314 default: 4315 break; 4316 } 4317 } 4318 4319 /** 4320 * @brief Trigger Security Request 4321 */ 4322 void sm_send_security_request(hci_con_handle_t con_handle){ 4323 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4324 if (!sm_conn) return; 4325 sm_send_security_request_for_connection(sm_conn); 4326 } 4327 4328 // request pairing 4329 void sm_request_pairing(hci_con_handle_t con_handle){ 4330 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4331 if (!sm_conn) return; // wrong connection 4332 4333 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4334 if (IS_RESPONDER(sm_conn->sm_role)){ 4335 sm_send_security_request_for_connection(sm_conn); 4336 } else { 4337 // used as a trigger to start central/master/initiator security procedures 4338 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4339 uint8_t ltk[16]; 4340 bool have_ltk; 4341 switch (sm_conn->sm_irk_lookup_state){ 4342 case IRK_LOOKUP_SUCCEEDED: 4343 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4344 have_ltk = !sm_is_null_key(ltk); 4345 log_info("have ltk %u", have_ltk); 4346 if (have_ltk){ 4347 sm_conn->sm_pairing_requested = 1; 4348 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4349 break; 4350 } 4351 /* fall through */ 4352 4353 case IRK_LOOKUP_FAILED: 4354 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4355 break; 4356 default: 4357 log_info("irk lookup pending"); 4358 sm_conn->sm_pairing_requested = 1; 4359 break; 4360 } 4361 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4362 sm_conn->sm_pairing_requested = 1; 4363 } 4364 } 4365 sm_trigger_run(); 4366 } 4367 4368 // called by client app on authorization request 4369 void sm_authorization_decline(hci_con_handle_t con_handle){ 4370 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4371 if (!sm_conn) return; // wrong connection 4372 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4373 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4374 } 4375 4376 void sm_authorization_grant(hci_con_handle_t con_handle){ 4377 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4378 if (!sm_conn) return; // wrong connection 4379 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4380 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4381 } 4382 4383 // GAP Bonding API 4384 4385 void sm_bonding_decline(hci_con_handle_t con_handle){ 4386 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4387 if (!sm_conn) return; // wrong connection 4388 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4389 log_info("decline, state %u", sm_conn->sm_engine_state); 4390 switch(sm_conn->sm_engine_state){ 4391 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4392 case SM_SC_W4_USER_RESPONSE: 4393 case SM_SC_W4_CONFIRMATION: 4394 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4395 #endif 4396 case SM_PH1_W4_USER_RESPONSE: 4397 switch (setup->sm_stk_generation_method){ 4398 case PK_RESP_INPUT: 4399 case PK_INIT_INPUT: 4400 case PK_BOTH_INPUT: 4401 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4402 break; 4403 case NUMERIC_COMPARISON: 4404 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4405 break; 4406 case JUST_WORKS: 4407 case OOB: 4408 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4409 break; 4410 default: 4411 btstack_assert(false); 4412 break; 4413 } 4414 break; 4415 default: 4416 break; 4417 } 4418 sm_trigger_run(); 4419 } 4420 4421 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4422 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4423 if (!sm_conn) return; // wrong connection 4424 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4425 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4426 if (setup->sm_use_secure_connections){ 4427 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4428 } else { 4429 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); 4430 } 4431 } 4432 4433 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4434 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4435 sm_sc_prepare_dhkey_check(sm_conn); 4436 } 4437 #endif 4438 4439 sm_trigger_run(); 4440 } 4441 4442 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4443 // for now, it's the same 4444 sm_just_works_confirm(con_handle); 4445 } 4446 4447 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4448 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4449 if (!sm_conn) return; // wrong connection 4450 sm_reset_tk(); 4451 big_endian_store_32(setup->sm_tk, 12, passkey); 4452 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4453 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4454 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); 4455 } 4456 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4457 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4458 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4459 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4460 sm_sc_start_calculating_local_confirm(sm_conn); 4461 } 4462 #endif 4463 sm_trigger_run(); 4464 } 4465 4466 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4467 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4468 if (!sm_conn) return; // wrong connection 4469 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4470 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4471 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4472 switch (action){ 4473 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4474 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4475 flags |= (1u << action); 4476 break; 4477 case SM_KEYPRESS_PASSKEY_CLEARED: 4478 // clear counter, keypress & erased flags + set passkey cleared 4479 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4480 break; 4481 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4482 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4483 // erase actions queued 4484 num_actions--; 4485 if (num_actions == 0u){ 4486 // clear counter, keypress & erased flags 4487 flags &= 0x19u; 4488 } 4489 break; 4490 } 4491 num_actions++; 4492 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4493 break; 4494 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4495 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4496 // enter actions queued 4497 num_actions--; 4498 if (num_actions == 0u){ 4499 // clear counter, keypress & erased flags 4500 flags &= 0x19u; 4501 } 4502 break; 4503 } 4504 num_actions++; 4505 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4506 break; 4507 default: 4508 break; 4509 } 4510 setup->sm_keypress_notification = (num_actions << 5) | flags; 4511 sm_trigger_run(); 4512 } 4513 4514 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4515 static void sm_handle_random_result_oob(void * arg){ 4516 UNUSED(arg); 4517 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4518 sm_trigger_run(); 4519 } 4520 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4521 4522 static btstack_crypto_random_t sm_crypto_random_oob_request; 4523 4524 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4525 sm_sc_oob_callback = callback; 4526 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4527 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4528 return 0; 4529 } 4530 #endif 4531 4532 /** 4533 * @brief Get Identity Resolving state 4534 * @param con_handle 4535 * @return irk_lookup_state_t 4536 */ 4537 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4538 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4539 if (!sm_conn) return IRK_LOOKUP_IDLE; 4540 return sm_conn->sm_irk_lookup_state; 4541 } 4542 4543 /** 4544 * @brief Identify device in LE Device DB 4545 * @param handle 4546 * @returns index from le_device_db or -1 if not found/identified 4547 */ 4548 int sm_le_device_index(hci_con_handle_t con_handle ){ 4549 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4550 if (!sm_conn) return -1; 4551 return sm_conn->sm_le_db_index; 4552 } 4553 4554 static int gap_random_address_type_requires_updates(void){ 4555 switch (gap_random_adress_type){ 4556 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4557 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4558 return 0; 4559 default: 4560 return 1; 4561 } 4562 } 4563 4564 static uint8_t own_address_type(void){ 4565 switch (gap_random_adress_type){ 4566 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4567 return BD_ADDR_TYPE_LE_PUBLIC; 4568 default: 4569 return BD_ADDR_TYPE_LE_RANDOM; 4570 } 4571 } 4572 4573 // GAP LE API 4574 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4575 gap_random_address_update_stop(); 4576 gap_random_adress_type = random_address_type; 4577 hci_le_set_own_address_type(own_address_type()); 4578 if (!gap_random_address_type_requires_updates()) return; 4579 gap_random_address_update_start(); 4580 gap_random_address_trigger(); 4581 } 4582 4583 gap_random_address_type_t gap_random_address_get_mode(void){ 4584 return gap_random_adress_type; 4585 } 4586 4587 void gap_random_address_set_update_period(int period_ms){ 4588 gap_random_adress_update_period = period_ms; 4589 if (!gap_random_address_type_requires_updates()) return; 4590 gap_random_address_update_stop(); 4591 gap_random_address_update_start(); 4592 } 4593 4594 void gap_random_address_set(const bd_addr_t addr){ 4595 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4596 (void)memcpy(sm_random_address, addr, 6); 4597 rau_state = RAU_SET_ADDRESS; 4598 sm_trigger_run(); 4599 } 4600 4601 #ifdef ENABLE_LE_PERIPHERAL 4602 /* 4603 * @brief Set Advertisement Paramters 4604 * @param adv_int_min 4605 * @param adv_int_max 4606 * @param adv_type 4607 * @param direct_address_type 4608 * @param direct_address 4609 * @param channel_map 4610 * @param filter_policy 4611 * 4612 * @note own_address_type is used from gap_random_address_set_mode 4613 */ 4614 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4615 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4616 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4617 direct_address_typ, direct_address, channel_map, filter_policy); 4618 } 4619 #endif 4620 4621 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4622 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4623 // wrong connection 4624 if (!sm_conn) return 0; 4625 // already encrypted 4626 if (sm_conn->sm_connection_encrypted) return 0; 4627 // only central can re-encrypt 4628 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4629 // irk status? 4630 switch(sm_conn->sm_irk_lookup_state){ 4631 case IRK_LOOKUP_FAILED: 4632 // done, cannot setup encryption 4633 return 0; 4634 case IRK_LOOKUP_SUCCEEDED: 4635 break; 4636 default: 4637 // IR Lookup pending 4638 return 1; 4639 } 4640 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4641 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4642 } 4643 4644 void sm_set_secure_connections_only_mode(bool enable){ 4645 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4646 sm_sc_only_mode = enable; 4647 #else 4648 // SC Only mode not possible without support for SC 4649 btstack_assert(enable == false); 4650 #endif 4651 } 4652 4653 const uint8_t * gap_get_persistent_irk(void){ 4654 return sm_persistent_irk; 4655 } 4656