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 bool sm_reencryption_active; 375 } sm_setup_context_t; 376 377 // 378 static sm_setup_context_t the_setup; 379 static sm_setup_context_t * setup = &the_setup; 380 381 // active connection - the one for which the_setup is used for 382 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 383 384 // @returns 1 if oob data is available 385 // stores oob data in provided 16 byte buffer if not null 386 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 387 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); 388 389 static void sm_run(void); 390 static void sm_done_for_handle(hci_con_handle_t con_handle); 391 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 392 static inline int sm_calc_actual_encryption_key_size(int other); 393 static int sm_validate_stk_generation_method(void); 394 static void sm_handle_encryption_result_address_resolution(void *arg); 395 static void sm_handle_encryption_result_dkg_dhk(void *arg); 396 static void sm_handle_encryption_result_dkg_irk(void *arg); 397 static void sm_handle_encryption_result_enc_a(void *arg); 398 static void sm_handle_encryption_result_enc_b(void *arg); 399 static void sm_handle_encryption_result_enc_c(void *arg); 400 static void sm_handle_encryption_result_enc_csrk(void *arg); 401 static void sm_handle_encryption_result_enc_d(void * arg); 402 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 403 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 404 #ifdef ENABLE_LE_PERIPHERAL 405 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 406 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 407 #endif 408 static void sm_handle_encryption_result_enc_stk(void *arg); 409 static void sm_handle_encryption_result_rau(void *arg); 410 static void sm_handle_random_result_ph2_tk(void * arg); 411 static void sm_handle_random_result_rau(void * arg); 412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 413 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)); 414 static void sm_ec_generate_new_key(void); 415 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 416 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 417 static int sm_passkey_entry(stk_generation_method_t method); 418 #endif 419 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 420 421 static void log_info_hex16(const char * name, uint16_t value){ 422 log_info("%-6s 0x%04x", name, value); 423 } 424 425 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 426 // return packet[0]; 427 // } 428 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 429 return packet[1]; 430 } 431 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 432 return packet[2]; 433 } 434 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 435 return packet[3]; 436 } 437 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 438 return packet[4]; 439 } 440 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 441 return packet[5]; 442 } 443 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 444 return packet[6]; 445 } 446 447 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 448 packet[0] = code; 449 } 450 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 451 packet[1] = io_capability; 452 } 453 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 454 packet[2] = oob_data_flag; 455 } 456 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 457 packet[3] = auth_req; 458 } 459 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 460 packet[4] = max_encryption_key_size; 461 } 462 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 463 packet[5] = initiator_key_distribution; 464 } 465 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 466 packet[6] = responder_key_distribution; 467 } 468 469 // @returns 1 if all bytes are 0 470 static int sm_is_null(uint8_t * data, int size){ 471 int i; 472 for (i=0; i < size ; i++){ 473 if (data[i] != 0) { 474 return 0; 475 } 476 } 477 return 1; 478 } 479 480 static int sm_is_null_random(uint8_t random[8]){ 481 return sm_is_null(random, 8); 482 } 483 484 static int sm_is_null_key(uint8_t * key){ 485 return sm_is_null(key, 16); 486 } 487 488 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 489 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 490 UNUSED(ts); 491 sm_run(); 492 } 493 static void sm_trigger_run(void){ 494 (void)btstack_run_loop_remove_timer(&sm_run_timer); 495 btstack_run_loop_set_timer(&sm_run_timer, 0); 496 btstack_run_loop_add_timer(&sm_run_timer); 497 } 498 499 // Key utils 500 static void sm_reset_tk(void){ 501 int i; 502 for (i=0;i<16;i++){ 503 setup->sm_tk[i] = 0; 504 } 505 } 506 507 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 508 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 509 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 510 int i; 511 for (i = max_encryption_size ; i < 16 ; i++){ 512 key[15-i] = 0; 513 } 514 } 515 516 // ER / IR checks 517 static void sm_er_ir_set_default(void){ 518 int i; 519 for (i=0;i<16;i++){ 520 sm_persistent_er[i] = 0x30 + i; 521 sm_persistent_ir[i] = 0x90 + i; 522 } 523 } 524 525 static int sm_er_is_default(void){ 526 int i; 527 for (i=0;i<16;i++){ 528 if (sm_persistent_er[i] != (0x30+i)) return 0; 529 } 530 return 1; 531 } 532 533 static int sm_ir_is_default(void){ 534 int i; 535 for (i=0;i<16;i++){ 536 if (sm_persistent_ir[i] != (0x90+i)) return 0; 537 } 538 return 1; 539 } 540 541 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 542 UNUSED(channel); 543 544 // log event 545 hci_dump_packet(packet_type, 1, packet, size); 546 // dispatch to all event handlers 547 btstack_linked_list_iterator_t it; 548 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 549 while (btstack_linked_list_iterator_has_next(&it)){ 550 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 551 entry->callback(packet_type, 0, packet, size); 552 } 553 } 554 555 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){ 556 event[0] = type; 557 event[1] = event_size - 2; 558 little_endian_store_16(event, 2, con_handle); 559 event[4] = addr_type; 560 reverse_bd_addr(address, &event[5]); 561 } 562 563 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 564 uint8_t event[11]; 565 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 566 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 567 } 568 569 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){ 570 uint8_t event[15]; 571 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 572 little_endian_store_32(event, 11, passkey); 573 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 574 } 575 576 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){ 577 // fetch addr and addr type from db, only called for valid entries 578 bd_addr_t identity_address; 579 int identity_address_type; 580 le_device_db_info(index, &identity_address_type, identity_address, NULL); 581 582 uint8_t event[20]; 583 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 584 event[11] = identity_address_type; 585 reverse_bd_addr(identity_address, &event[12]); 586 little_endian_store_16(event, 18, index); 587 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 588 } 589 590 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){ 591 uint8_t event[12]; 592 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 593 event[11] = status; 594 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 595 } 596 597 598 static void sm_reencryption_started(sm_connection_t * sm_conn){ 599 600 setup->sm_reencryption_active = true; 601 602 // fetch addr and addr type from db, only called for valid entries 603 int identity_addr_type; 604 bd_addr_t identity_addr; 605 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 606 607 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 608 } 609 610 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 611 612 setup->sm_reencryption_active = false; 613 614 // fetch addr and addr type from db, only called for valid entries 615 int identity_addr_type; 616 bd_addr_t identity_addr; 617 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 618 619 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 620 } 621 622 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 623 uint8_t event[13]; 624 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 625 event[11] = status; 626 event[12] = reason; 627 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 628 } 629 630 // SMP Timeout implementation 631 632 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 633 // the Security Manager Timer shall be reset and started. 634 // 635 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 636 // 637 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 638 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 639 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 640 // established. 641 642 static void sm_timeout_handler(btstack_timer_source_t * timer){ 643 log_info("SM timeout"); 644 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 645 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 646 647 if (setup->sm_reencryption_active){ 648 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 649 } 650 651 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 652 sm_done_for_handle(sm_conn->sm_handle); 653 654 // trigger handling of next ready connection 655 sm_run(); 656 } 657 static void sm_timeout_start(sm_connection_t * sm_conn){ 658 btstack_run_loop_remove_timer(&setup->sm_timeout); 659 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 660 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 661 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 662 btstack_run_loop_add_timer(&setup->sm_timeout); 663 } 664 static void sm_timeout_stop(void){ 665 btstack_run_loop_remove_timer(&setup->sm_timeout); 666 } 667 static void sm_timeout_reset(sm_connection_t * sm_conn){ 668 sm_timeout_stop(); 669 sm_timeout_start(sm_conn); 670 } 671 672 // end of sm timeout 673 674 // GAP Random Address updates 675 static gap_random_address_type_t gap_random_adress_type; 676 static btstack_timer_source_t gap_random_address_update_timer; 677 static uint32_t gap_random_adress_update_period; 678 679 static void gap_random_address_trigger(void){ 680 log_info("gap_random_address_trigger, state %u", rau_state); 681 if (rau_state != RAU_IDLE) return; 682 rau_state = RAU_GET_RANDOM; 683 sm_trigger_run(); 684 } 685 686 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 687 UNUSED(timer); 688 689 log_info("GAP Random Address Update due"); 690 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 691 btstack_run_loop_add_timer(&gap_random_address_update_timer); 692 gap_random_address_trigger(); 693 } 694 695 static void gap_random_address_update_start(void){ 696 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 697 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 698 btstack_run_loop_add_timer(&gap_random_address_update_timer); 699 } 700 701 static void gap_random_address_update_stop(void){ 702 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 703 } 704 705 // ah(k,r) helper 706 // r = padding || r 707 // r - 24 bit value 708 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 709 // r'= padding || r 710 memset(r_prime, 0, 16); 711 (void)memcpy(&r_prime[13], r, 3); 712 } 713 714 // d1 helper 715 // d' = padding || r || d 716 // d,r - 16 bit values 717 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 718 // d'= padding || r || d 719 memset(d1_prime, 0, 16); 720 big_endian_store_16(d1_prime, 12, r); 721 big_endian_store_16(d1_prime, 14, d); 722 } 723 724 // calculate arguments for first AES128 operation in C1 function 725 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){ 726 727 // p1 = pres || preq || rat’ || iat’ 728 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 729 // cant octet of pres becomes the most significant octet of p1. 730 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 731 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 732 // p1 is 0x05000800000302070710000001010001." 733 734 sm_key_t p1; 735 reverse_56(pres, &p1[0]); 736 reverse_56(preq, &p1[7]); 737 p1[14] = rat; 738 p1[15] = iat; 739 log_info_key("p1", p1); 740 log_info_key("r", r); 741 742 // t1 = r xor p1 743 int i; 744 for (i=0;i<16;i++){ 745 t1[i] = r[i] ^ p1[i]; 746 } 747 log_info_key("t1", t1); 748 } 749 750 // calculate arguments for second AES128 operation in C1 function 751 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 752 // p2 = padding || ia || ra 753 // "The least significant octet of ra becomes the least significant octet of p2 and 754 // the most significant octet of padding becomes the most significant octet of p2. 755 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 756 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 757 758 sm_key_t p2; 759 memset(p2, 0, 16); 760 (void)memcpy(&p2[4], ia, 6); 761 (void)memcpy(&p2[10], ra, 6); 762 log_info_key("p2", p2); 763 764 // c1 = e(k, t2_xor_p2) 765 int i; 766 for (i=0;i<16;i++){ 767 t3[i] = t2[i] ^ p2[i]; 768 } 769 log_info_key("t3", t3); 770 } 771 772 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 773 log_info_key("r1", r1); 774 log_info_key("r2", r2); 775 (void)memcpy(&r_prime[8], &r2[8], 8); 776 (void)memcpy(&r_prime[0], &r1[8], 8); 777 } 778 779 780 // decide on stk generation based on 781 // - pairing request 782 // - io capabilities 783 // - OOB data availability 784 static void sm_setup_tk(void){ 785 786 // horizontal: initiator capabilities 787 // vertial: responder capabilities 788 static const stk_generation_method_t stk_generation_method [5] [5] = { 789 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 790 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 791 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 792 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 793 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 794 }; 795 796 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 797 #ifdef ENABLE_LE_SECURE_CONNECTIONS 798 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 799 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 800 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 801 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 802 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 803 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 804 }; 805 #endif 806 807 // default: just works 808 setup->sm_stk_generation_method = JUST_WORKS; 809 810 #ifdef ENABLE_LE_SECURE_CONNECTIONS 811 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 812 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 813 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 814 #else 815 setup->sm_use_secure_connections = 0; 816 #endif 817 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 818 819 820 // decide if OOB will be used based on SC vs. Legacy and oob flags 821 int use_oob = 0; 822 if (setup->sm_use_secure_connections){ 823 // In LE Secure Connections pairing, the out of band method is used if at least 824 // one device has the peer device's out of band authentication data available. 825 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 826 } else { 827 // In LE legacy pairing, the out of band method is used if both the devices have 828 // the other device's out of band authentication data available. 829 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 830 } 831 if (use_oob){ 832 log_info("SM: have OOB data"); 833 log_info_key("OOB", setup->sm_tk); 834 setup->sm_stk_generation_method = OOB; 835 return; 836 } 837 838 // If both devices have not set the MITM option in the Authentication Requirements 839 // Flags, then the IO capabilities shall be ignored and the Just Works association 840 // model shall be used. 841 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 842 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 843 log_info("SM: MITM not required by both -> JUST WORKS"); 844 return; 845 } 846 847 // Reset TK as it has been setup in sm_init_setup 848 sm_reset_tk(); 849 850 // Also use just works if unknown io capabilites 851 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)){ 852 return; 853 } 854 855 // Otherwise the IO capabilities of the devices shall be used to determine the 856 // pairing method as defined in Table 2.4. 857 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 858 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 859 860 #ifdef ENABLE_LE_SECURE_CONNECTIONS 861 // table not define by default 862 if (setup->sm_use_secure_connections){ 863 generation_method = stk_generation_method_with_secure_connection; 864 } 865 #endif 866 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)]; 867 868 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 869 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); 870 } 871 872 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 873 int flags = 0; 874 if (key_set & SM_KEYDIST_ENC_KEY){ 875 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 876 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 877 } 878 if (key_set & SM_KEYDIST_ID_KEY){ 879 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 880 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 881 } 882 if (key_set & SM_KEYDIST_SIGN){ 883 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 884 } 885 return flags; 886 } 887 888 static void sm_setup_key_distribution(uint8_t key_set){ 889 setup->sm_key_distribution_received_set = 0; 890 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 891 setup->sm_key_distribution_sent_set = 0; 892 #ifdef ENABLE_LE_SIGNED_WRITE 893 setup->sm_le_device_index = -1; 894 #endif 895 } 896 897 // CSRK Key Lookup 898 899 900 static int sm_address_resolution_idle(void){ 901 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 902 } 903 904 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){ 905 (void)memcpy(sm_address_resolution_address, addr, 6); 906 sm_address_resolution_addr_type = addr_type; 907 sm_address_resolution_test = 0; 908 sm_address_resolution_mode = mode; 909 sm_address_resolution_context = context; 910 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 911 } 912 913 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 914 // check if already in list 915 btstack_linked_list_iterator_t it; 916 sm_lookup_entry_t * entry; 917 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 918 while(btstack_linked_list_iterator_has_next(&it)){ 919 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 920 if (entry->address_type != address_type) continue; 921 if (memcmp(entry->address, address, 6)) continue; 922 // already in list 923 return BTSTACK_BUSY; 924 } 925 entry = btstack_memory_sm_lookup_entry_get(); 926 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 927 entry->address_type = (bd_addr_type_t) address_type; 928 (void)memcpy(entry->address, address, 6); 929 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 930 sm_trigger_run(); 931 return 0; 932 } 933 934 // CMAC calculation using AES Engineq 935 #ifdef USE_CMAC_ENGINE 936 937 static void sm_cmac_done_trampoline(void * arg){ 938 UNUSED(arg); 939 sm_cmac_active = 0; 940 (*sm_cmac_done_callback)(sm_cmac_hash); 941 sm_trigger_run(); 942 } 943 944 int sm_cmac_ready(void){ 945 return sm_cmac_active == 0u; 946 } 947 #endif 948 949 #ifdef ENABLE_LE_SECURE_CONNECTIONS 950 // generic cmac calculation 951 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)){ 952 sm_cmac_active = 1; 953 sm_cmac_done_callback = done_callback; 954 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 955 } 956 #endif 957 958 // cmac for ATT Message signing 959 #ifdef ENABLE_LE_SIGNED_WRITE 960 961 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)){ 962 sm_cmac_active = 1; 963 sm_cmac_done_callback = done_callback; 964 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 965 } 966 967 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 968 if (offset >= sm_cmac_signed_write_message_len) { 969 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 970 return 0; 971 } 972 973 offset = sm_cmac_signed_write_message_len - 1 - offset; 974 975 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 976 if (offset < 3){ 977 return sm_cmac_signed_write_header[offset]; 978 } 979 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 980 if (offset < actual_message_len_incl_header){ 981 return sm_cmac_signed_write_message[offset - 3]; 982 } 983 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 984 } 985 986 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)){ 987 // ATT Message Signing 988 sm_cmac_signed_write_header[0] = opcode; 989 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 990 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 991 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 992 sm_cmac_signed_write_message = message; 993 sm_cmac_signed_write_message_len = total_message_len; 994 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 995 } 996 #endif 997 998 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 999 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1000 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1001 switch (setup->sm_stk_generation_method){ 1002 case PK_RESP_INPUT: 1003 if (IS_RESPONDER(sm_conn->sm_role)){ 1004 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1005 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1006 } else { 1007 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)); 1008 } 1009 break; 1010 case PK_INIT_INPUT: 1011 if (IS_RESPONDER(sm_conn->sm_role)){ 1012 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)); 1013 } else { 1014 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1015 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1016 } 1017 break; 1018 case PK_BOTH_INPUT: 1019 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1020 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1021 break; 1022 case NUMERIC_COMPARISON: 1023 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1024 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)); 1025 break; 1026 case JUST_WORKS: 1027 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1028 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1029 break; 1030 case OOB: 1031 // client already provided OOB data, let's skip notification. 1032 break; 1033 default: 1034 btstack_assert(false); 1035 break; 1036 } 1037 } 1038 1039 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1040 int recv_flags; 1041 if (IS_RESPONDER(sm_conn->sm_role)){ 1042 // slave / responder 1043 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1044 } else { 1045 // master / initiator 1046 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1047 } 1048 1049 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1050 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1051 if (setup->sm_use_secure_connections){ 1052 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1053 } 1054 #endif 1055 1056 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1057 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1058 } 1059 1060 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1061 if (sm_active_connection_handle == con_handle){ 1062 sm_timeout_stop(); 1063 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1064 log_info("sm: connection 0x%x released setup context", con_handle); 1065 1066 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1067 // generate new ec key after each pairing (that used it) 1068 if (setup->sm_use_secure_connections){ 1069 sm_ec_generate_new_key(); 1070 } 1071 #endif 1072 } 1073 } 1074 1075 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1076 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1077 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1078 sm_done_for_handle(connection->sm_handle); 1079 } 1080 1081 static int sm_key_distribution_flags_for_auth_req(void){ 1082 1083 int flags = SM_KEYDIST_ID_KEY; 1084 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1085 // encryption and signing information only if bonding requested 1086 flags |= SM_KEYDIST_ENC_KEY; 1087 #ifdef ENABLE_LE_SIGNED_WRITE 1088 flags |= SM_KEYDIST_SIGN; 1089 #endif 1090 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1091 // LinkKey for CTKD requires SC 1092 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1093 flags |= SM_KEYDIST_LINK_KEY; 1094 } 1095 #endif 1096 } 1097 return flags; 1098 } 1099 1100 static void sm_reset_setup(void){ 1101 // fill in sm setup 1102 setup->sm_state_vars = 0; 1103 setup->sm_keypress_notification = 0; 1104 sm_reset_tk(); 1105 setup->sm_reencryption_active = false; 1106 } 1107 1108 static void sm_init_setup(sm_connection_t * sm_conn){ 1109 1110 // fill in sm setup 1111 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1112 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1113 1114 // query client for Legacy Pairing OOB data 1115 setup->sm_have_oob_data = 0; 1116 if (sm_get_oob_data) { 1117 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1118 } 1119 1120 // if available and SC supported, also ask for SC OOB Data 1121 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1122 memset(setup->sm_ra, 0, 16); 1123 memset(setup->sm_rb, 0, 16); 1124 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1125 if (sm_get_sc_oob_data){ 1126 if (IS_RESPONDER(sm_conn->sm_role)){ 1127 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1128 sm_conn->sm_peer_addr_type, 1129 sm_conn->sm_peer_address, 1130 setup->sm_peer_confirm, 1131 setup->sm_ra); 1132 } else { 1133 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1134 sm_conn->sm_peer_addr_type, 1135 sm_conn->sm_peer_address, 1136 setup->sm_peer_confirm, 1137 setup->sm_rb); 1138 } 1139 } else { 1140 setup->sm_have_oob_data = 0; 1141 } 1142 } 1143 #endif 1144 1145 sm_pairing_packet_t * local_packet; 1146 if (IS_RESPONDER(sm_conn->sm_role)){ 1147 // slave 1148 local_packet = &setup->sm_s_pres; 1149 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1150 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1151 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1152 } else { 1153 // master 1154 local_packet = &setup->sm_m_preq; 1155 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1156 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1157 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1158 1159 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1160 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1161 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1162 } 1163 1164 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1165 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1166 // set CT2 if SC + Bonding + CTKD 1167 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1168 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1169 auth_req |= SM_AUTHREQ_CT2; 1170 } 1171 #endif 1172 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1173 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1174 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1175 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1176 } 1177 1178 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1179 1180 sm_pairing_packet_t * remote_packet; 1181 int remote_key_request; 1182 if (IS_RESPONDER(sm_conn->sm_role)){ 1183 // slave / responder 1184 remote_packet = &setup->sm_m_preq; 1185 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1186 } else { 1187 // master / initiator 1188 remote_packet = &setup->sm_s_pres; 1189 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1190 } 1191 1192 // check key size 1193 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1194 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1195 1196 // decide on STK generation method / SC 1197 sm_setup_tk(); 1198 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1199 1200 // check if STK generation method is acceptable by client 1201 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1202 1203 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1204 // check LE SC Only mode 1205 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1206 log_info("SC Only mode active but SC not possible"); 1207 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1208 } 1209 1210 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1211 if (setup->sm_use_secure_connections){ 1212 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1213 } 1214 #endif 1215 1216 // identical to responder 1217 sm_setup_key_distribution(remote_key_request); 1218 1219 // JUST WORKS doens't provide authentication 1220 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1221 1222 return 0; 1223 } 1224 1225 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1226 1227 // cache and reset context 1228 int matched_device_id = sm_address_resolution_test; 1229 address_resolution_mode_t mode = sm_address_resolution_mode; 1230 void * context = sm_address_resolution_context; 1231 1232 // reset context 1233 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1234 sm_address_resolution_context = NULL; 1235 sm_address_resolution_test = -1; 1236 hci_con_handle_t con_handle = 0; 1237 1238 sm_connection_t * sm_connection; 1239 sm_key_t ltk; 1240 int have_ltk; 1241 #ifdef ENABLE_LE_CENTRAL 1242 int trigger_pairing; 1243 #endif 1244 switch (mode){ 1245 case ADDRESS_RESOLUTION_GENERAL: 1246 break; 1247 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1248 sm_connection = (sm_connection_t *) context; 1249 con_handle = sm_connection->sm_handle; 1250 1251 // have ltk -> start encryption / send security request 1252 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1253 // "When a bond has been created between two devices, any reconnection should result in the local device 1254 // enabling or requesting encryption with the remote device before initiating any service request." 1255 1256 switch (event){ 1257 case ADDRESS_RESOLUTION_SUCCEEDED: 1258 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1259 sm_connection->sm_le_db_index = matched_device_id; 1260 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1261 1262 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1263 have_ltk = !sm_is_null_key(ltk); 1264 1265 if (sm_connection->sm_role) { 1266 1267 #ifdef ENABLE_LE_PERIPHERAL 1268 1269 // LTK request received before, IRK required -> start LTK calculation 1270 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1271 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1272 break; 1273 } 1274 1275 if (have_ltk) { 1276 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1277 log_info("central: enable encryption for bonded device"); 1278 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1279 sm_reencryption_started(sm_connection); 1280 sm_trigger_run(); 1281 #else 1282 log_info("central: defer security request for bonded device"); 1283 #endif 1284 } 1285 #endif 1286 } else { 1287 1288 #ifdef ENABLE_LE_CENTRAL 1289 1290 // check if pairing already requested and reset requests 1291 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1292 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1293 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, trigger_pairing, have_ltk); 1294 sm_connection->sm_security_request_received = 0; 1295 sm_connection->sm_pairing_requested = 0; 1296 bool trigger_reencryption = false; 1297 1298 if (have_ltk){ 1299 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1300 trgigger_reencryptipm = true; 1301 #else 1302 if (trigger_pairing){ 1303 trigger_reencryption = true; 1304 } else { 1305 log_info("central: defer enabling encryption for bonded device"); 1306 } 1307 #endif 1308 } 1309 1310 if (trigger_reencryption){ 1311 log_info("central: enable encryption for bonded device"); 1312 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1313 sm_reencryption_started(sm_connection); 1314 break; 1315 } 1316 1317 // pairing_request -> send pairing request 1318 if (trigger_pairing){ 1319 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1320 break; 1321 } 1322 } 1323 #endif 1324 break; 1325 case ADDRESS_RESOLUTION_FAILED: 1326 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1327 if (sm_connection->sm_role) { 1328 // LTK request received before, IRK required -> negative LTK reply 1329 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1330 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1331 } 1332 break; 1333 } 1334 #ifdef ENABLE_LE_CENTRAL 1335 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1336 sm_connection->sm_security_request_received = 0; 1337 sm_connection->sm_pairing_requested = 0; 1338 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1339 #endif 1340 break; 1341 1342 default: 1343 btstack_assert(false); 1344 break; 1345 } 1346 break; 1347 default: 1348 break; 1349 } 1350 1351 switch (event){ 1352 case ADDRESS_RESOLUTION_SUCCEEDED: 1353 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1354 break; 1355 case ADDRESS_RESOLUTION_FAILED: 1356 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1357 break; 1358 default: 1359 btstack_assert(false); 1360 break; 1361 } 1362 } 1363 1364 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1365 1366 int le_db_index = -1; 1367 1368 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1369 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1370 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1371 & SM_AUTHREQ_BONDING ) != 0u; 1372 1373 if (bonding_enabed){ 1374 1375 // lookup device based on IRK 1376 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1377 int i; 1378 for (i=0; i < le_device_db_max_count(); i++){ 1379 sm_key_t irk; 1380 bd_addr_t address; 1381 int address_type = BD_ADDR_TYPE_UNKNOWN; 1382 le_device_db_info(i, &address_type, address, irk); 1383 // skip unused entries 1384 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1385 // compare IRK 1386 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1387 1388 log_info("sm: device found for IRK, updating"); 1389 le_db_index = i; 1390 break; 1391 } 1392 } else { 1393 // assert IRK is set to zero 1394 memset(setup->sm_peer_irk, 0, 16); 1395 } 1396 1397 // if not found, lookup via public address if possible 1398 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1399 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1400 int i; 1401 for (i=0; i < le_device_db_max_count(); i++){ 1402 bd_addr_t address; 1403 int address_type = BD_ADDR_TYPE_UNKNOWN; 1404 le_device_db_info(i, &address_type, address, NULL); 1405 // skip unused entries 1406 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1407 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1408 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1409 log_info("sm: device found for public address, updating"); 1410 le_db_index = i; 1411 break; 1412 } 1413 } 1414 } 1415 1416 // if not found, add to db 1417 bool new_to_le_device_db = false; 1418 if (le_db_index < 0) { 1419 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1420 new_to_le_device_db = true; 1421 } 1422 1423 if (le_db_index >= 0){ 1424 1425 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1426 if (!new_to_le_device_db){ 1427 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1428 } 1429 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1430 #else 1431 UNUSED(new_to_le_device_db); 1432 #endif 1433 1434 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1435 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1436 1437 #ifdef ENABLE_LE_SIGNED_WRITE 1438 // store local CSRK 1439 setup->sm_le_device_index = le_db_index; 1440 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1441 log_info("sm: store local CSRK"); 1442 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1443 le_device_db_local_counter_set(le_db_index, 0); 1444 } 1445 1446 // store remote CSRK 1447 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1448 log_info("sm: store remote CSRK"); 1449 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1450 le_device_db_remote_counter_set(le_db_index, 0); 1451 } 1452 #endif 1453 // store encryption information for secure connections: LTK generated by ECDH 1454 if (setup->sm_use_secure_connections){ 1455 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1456 uint8_t zero_rand[8]; 1457 memset(zero_rand, 0, 8); 1458 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1459 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1460 } 1461 1462 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1463 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1464 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1465 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1466 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1467 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1468 1469 } 1470 } 1471 } else { 1472 log_info("Ignoring received keys, bonding not enabled"); 1473 } 1474 1475 // keep le_db_index 1476 sm_conn->sm_le_db_index = le_db_index; 1477 } 1478 1479 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1480 setup->sm_pairing_failed_reason = reason; 1481 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1482 } 1483 1484 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1485 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1486 } 1487 1488 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1489 1490 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1491 static int sm_passkey_used(stk_generation_method_t method); 1492 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1493 1494 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1495 if (setup->sm_stk_generation_method == OOB){ 1496 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1497 } else { 1498 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); 1499 } 1500 } 1501 1502 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1503 if (IS_RESPONDER(sm_conn->sm_role)){ 1504 // Responder 1505 if (setup->sm_stk_generation_method == OOB){ 1506 // generate Nb 1507 log_info("Generate Nb"); 1508 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); 1509 } else { 1510 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1511 } 1512 } else { 1513 // Initiator role 1514 switch (setup->sm_stk_generation_method){ 1515 case JUST_WORKS: 1516 sm_sc_prepare_dhkey_check(sm_conn); 1517 break; 1518 1519 case NUMERIC_COMPARISON: 1520 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1521 break; 1522 case PK_INIT_INPUT: 1523 case PK_RESP_INPUT: 1524 case PK_BOTH_INPUT: 1525 if (setup->sm_passkey_bit < 20u) { 1526 sm_sc_start_calculating_local_confirm(sm_conn); 1527 } else { 1528 sm_sc_prepare_dhkey_check(sm_conn); 1529 } 1530 break; 1531 case OOB: 1532 sm_sc_prepare_dhkey_check(sm_conn); 1533 break; 1534 default: 1535 btstack_assert(false); 1536 break; 1537 } 1538 } 1539 } 1540 1541 static void sm_sc_cmac_done(uint8_t * hash){ 1542 log_info("sm_sc_cmac_done: "); 1543 log_info_hexdump(hash, 16); 1544 1545 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1546 sm_sc_oob_state = SM_SC_OOB_IDLE; 1547 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1548 return; 1549 } 1550 1551 sm_connection_t * sm_conn = sm_cmac_connection; 1552 sm_cmac_connection = NULL; 1553 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1554 link_key_type_t link_key_type; 1555 #endif 1556 1557 switch (sm_conn->sm_engine_state){ 1558 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1559 (void)memcpy(setup->sm_local_confirm, hash, 16); 1560 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1561 break; 1562 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1563 // check 1564 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1565 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1566 break; 1567 } 1568 sm_sc_state_after_receiving_random(sm_conn); 1569 break; 1570 case SM_SC_W4_CALCULATE_G2: { 1571 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1572 big_endian_store_32(setup->sm_tk, 12, vab); 1573 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1574 sm_trigger_user_response(sm_conn); 1575 break; 1576 } 1577 case SM_SC_W4_CALCULATE_F5_SALT: 1578 (void)memcpy(setup->sm_t, hash, 16); 1579 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1580 break; 1581 case SM_SC_W4_CALCULATE_F5_MACKEY: 1582 (void)memcpy(setup->sm_mackey, hash, 16); 1583 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1584 break; 1585 case SM_SC_W4_CALCULATE_F5_LTK: 1586 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1587 // Errata Service Release to the Bluetooth Specification: ESR09 1588 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1589 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1590 (void)memcpy(setup->sm_ltk, hash, 16); 1591 (void)memcpy(setup->sm_local_ltk, hash, 16); 1592 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1593 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1594 break; 1595 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1596 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1597 if (IS_RESPONDER(sm_conn->sm_role)){ 1598 // responder 1599 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1600 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1601 } else { 1602 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1603 } 1604 } else { 1605 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1606 } 1607 break; 1608 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1609 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1610 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1611 break; 1612 } 1613 if (IS_RESPONDER(sm_conn->sm_role)){ 1614 // responder 1615 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1616 } else { 1617 // initiator 1618 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1619 } 1620 break; 1621 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1622 case SM_SC_W4_CALCULATE_ILK: 1623 (void)memcpy(setup->sm_t, hash, 16); 1624 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1625 break; 1626 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1627 reverse_128(hash, setup->sm_t); 1628 link_key_type = sm_conn->sm_connection_authenticated ? 1629 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1630 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1631 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1632 if (IS_RESPONDER(sm_conn->sm_role)){ 1633 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1634 } else { 1635 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1636 } 1637 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1638 sm_done_for_handle(sm_conn->sm_handle); 1639 break; 1640 #endif 1641 default: 1642 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1643 break; 1644 } 1645 sm_trigger_run(); 1646 } 1647 1648 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){ 1649 const uint16_t message_len = 65; 1650 sm_cmac_connection = sm_conn; 1651 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1652 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1653 sm_cmac_sc_buffer[64] = z; 1654 log_info("f4 key"); 1655 log_info_hexdump(x, 16); 1656 log_info("f4 message"); 1657 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1658 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1659 } 1660 1661 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1662 static const uint8_t f5_length[] = { 0x01, 0x00}; 1663 1664 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1665 1666 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1667 1668 log_info("f5_calculate_salt"); 1669 // calculate salt for f5 1670 const uint16_t message_len = 32; 1671 sm_cmac_connection = sm_conn; 1672 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1673 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1674 } 1675 1676 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){ 1677 const uint16_t message_len = 53; 1678 sm_cmac_connection = sm_conn; 1679 1680 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1681 sm_cmac_sc_buffer[0] = 0; 1682 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1683 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1684 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1685 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1686 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1687 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1688 log_info("f5 key"); 1689 log_info_hexdump(t, 16); 1690 log_info("f5 message for MacKey"); 1691 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1692 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1693 } 1694 1695 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1696 sm_key56_t bd_addr_master, bd_addr_slave; 1697 bd_addr_master[0] = setup->sm_m_addr_type; 1698 bd_addr_slave[0] = setup->sm_s_addr_type; 1699 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1700 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1701 if (IS_RESPONDER(sm_conn->sm_role)){ 1702 // responder 1703 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1704 } else { 1705 // initiator 1706 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1707 } 1708 } 1709 1710 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1711 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1712 const uint16_t message_len = 53; 1713 sm_cmac_connection = sm_conn; 1714 sm_cmac_sc_buffer[0] = 1; 1715 // 1..52 setup before 1716 log_info("f5 key"); 1717 log_info_hexdump(t, 16); 1718 log_info("f5 message for LTK"); 1719 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1720 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1721 } 1722 1723 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1724 f5_ltk(sm_conn, setup->sm_t); 1725 } 1726 1727 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){ 1728 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1729 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1730 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1731 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1732 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1733 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1734 } 1735 1736 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1737 const uint16_t message_len = 65; 1738 sm_cmac_connection = sm_conn; 1739 log_info("f6 key"); 1740 log_info_hexdump(w, 16); 1741 log_info("f6 message"); 1742 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1743 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1744 } 1745 1746 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1747 // - U is 256 bits 1748 // - V is 256 bits 1749 // - X is 128 bits 1750 // - Y is 128 bits 1751 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){ 1752 const uint16_t message_len = 80; 1753 sm_cmac_connection = sm_conn; 1754 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1755 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1756 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1757 log_info("g2 key"); 1758 log_info_hexdump(x, 16); 1759 log_info("g2 message"); 1760 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1761 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1762 } 1763 1764 static void g2_calculate(sm_connection_t * sm_conn) { 1765 // calc Va if numeric comparison 1766 if (IS_RESPONDER(sm_conn->sm_role)){ 1767 // responder 1768 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1769 } else { 1770 // initiator 1771 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1772 } 1773 } 1774 1775 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1776 uint8_t z = 0; 1777 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1778 // some form of passkey 1779 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1780 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1781 setup->sm_passkey_bit++; 1782 } 1783 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1784 } 1785 1786 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1787 // OOB 1788 if (setup->sm_stk_generation_method == OOB){ 1789 if (IS_RESPONDER(sm_conn->sm_role)){ 1790 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1791 } else { 1792 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1793 } 1794 return; 1795 } 1796 1797 uint8_t z = 0; 1798 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1799 // some form of passkey 1800 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1801 // sm_passkey_bit was increased before sending confirm value 1802 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1803 } 1804 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1805 } 1806 1807 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1808 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1809 1810 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1811 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1812 return; 1813 } else { 1814 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1815 } 1816 } 1817 1818 static void sm_sc_dhkey_calculated(void * arg){ 1819 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1820 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1821 if (sm_conn == NULL) return; 1822 1823 log_info("dhkey"); 1824 log_info_hexdump(&setup->sm_dhkey[0], 32); 1825 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1826 // trigger next step 1827 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1828 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1829 } 1830 sm_trigger_run(); 1831 } 1832 1833 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1834 // calculate DHKCheck 1835 sm_key56_t bd_addr_master, bd_addr_slave; 1836 bd_addr_master[0] = setup->sm_m_addr_type; 1837 bd_addr_slave[0] = setup->sm_s_addr_type; 1838 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1839 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1840 uint8_t iocap_a[3]; 1841 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1842 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1843 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1844 uint8_t iocap_b[3]; 1845 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1846 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1847 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1848 if (IS_RESPONDER(sm_conn->sm_role)){ 1849 // responder 1850 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1851 f6_engine(sm_conn, setup->sm_mackey); 1852 } else { 1853 // initiator 1854 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1855 f6_engine(sm_conn, setup->sm_mackey); 1856 } 1857 } 1858 1859 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1860 // validate E = f6() 1861 sm_key56_t bd_addr_master, bd_addr_slave; 1862 bd_addr_master[0] = setup->sm_m_addr_type; 1863 bd_addr_slave[0] = setup->sm_s_addr_type; 1864 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1865 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1866 1867 uint8_t iocap_a[3]; 1868 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1869 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1870 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1871 uint8_t iocap_b[3]; 1872 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1873 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1874 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1875 if (IS_RESPONDER(sm_conn->sm_role)){ 1876 // responder 1877 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1878 f6_engine(sm_conn, setup->sm_mackey); 1879 } else { 1880 // initiator 1881 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1882 f6_engine(sm_conn, setup->sm_mackey); 1883 } 1884 } 1885 1886 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1887 1888 // 1889 // Link Key Conversion Function h6 1890 // 1891 // h6(W, keyID) = AES-CMAC_W(keyID) 1892 // - W is 128 bits 1893 // - keyID is 32 bits 1894 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1895 const uint16_t message_len = 4; 1896 sm_cmac_connection = sm_conn; 1897 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1898 log_info("h6 key"); 1899 log_info_hexdump(w, 16); 1900 log_info("h6 message"); 1901 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1902 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1903 } 1904 // 1905 // Link Key Conversion Function h7 1906 // 1907 // h7(SALT, W) = AES-CMAC_SALT(W) 1908 // - SALT is 128 bits 1909 // - W is 128 bits 1910 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1911 const uint16_t message_len = 16; 1912 sm_cmac_connection = sm_conn; 1913 log_info("h7 key"); 1914 log_info_hexdump(salt, 16); 1915 log_info("h7 message"); 1916 log_info_hexdump(w, 16); 1917 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1918 } 1919 1920 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1921 // Errata Service Release to the Bluetooth Specification: ESR09 1922 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1923 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1924 1925 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1926 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1927 } 1928 1929 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1930 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1931 } 1932 1933 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1934 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1935 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1936 } 1937 #endif 1938 1939 #endif 1940 1941 // key management legacy connections: 1942 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1943 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1944 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1945 // - responder reconnects: responder uses LTK receveived from master 1946 1947 // key management secure connections: 1948 // - both devices store same LTK from ECDH key exchange. 1949 1950 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1951 static void sm_load_security_info(sm_connection_t * sm_connection){ 1952 int encryption_key_size; 1953 int authenticated; 1954 int authorized; 1955 int secure_connection; 1956 1957 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1958 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1959 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1960 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); 1961 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1962 sm_connection->sm_connection_authenticated = authenticated; 1963 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1964 sm_connection->sm_connection_sc = secure_connection; 1965 } 1966 #endif 1967 1968 #ifdef ENABLE_LE_PERIPHERAL 1969 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1970 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1971 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1972 // re-establish used key encryption size 1973 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1974 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1975 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1976 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1977 // Legacy paring -> not SC 1978 sm_connection->sm_connection_sc = 0; 1979 log_info("sm: received ltk request with key size %u, authenticated %u", 1980 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1981 } 1982 #endif 1983 1984 // distributed key generation 1985 static bool sm_run_dpkg(void){ 1986 switch (dkg_state){ 1987 case DKG_CALC_IRK: 1988 // already busy? 1989 if (sm_aes128_state == SM_AES128_IDLE) { 1990 log_info("DKG_CALC_IRK started"); 1991 // IRK = d1(IR, 1, 0) 1992 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1993 sm_aes128_state = SM_AES128_ACTIVE; 1994 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1995 return true; 1996 } 1997 break; 1998 case DKG_CALC_DHK: 1999 // already busy? 2000 if (sm_aes128_state == SM_AES128_IDLE) { 2001 log_info("DKG_CALC_DHK started"); 2002 // DHK = d1(IR, 3, 0) 2003 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2004 sm_aes128_state = SM_AES128_ACTIVE; 2005 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2006 return true; 2007 } 2008 break; 2009 default: 2010 break; 2011 } 2012 return false; 2013 } 2014 2015 // random address updates 2016 static bool sm_run_rau(void){ 2017 switch (rau_state){ 2018 case RAU_GET_RANDOM: 2019 rau_state = RAU_W4_RANDOM; 2020 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2021 return true; 2022 case RAU_GET_ENC: 2023 // already busy? 2024 if (sm_aes128_state == SM_AES128_IDLE) { 2025 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2026 sm_aes128_state = SM_AES128_ACTIVE; 2027 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2028 return true; 2029 } 2030 break; 2031 case RAU_SET_ADDRESS: 2032 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2033 rau_state = RAU_IDLE; 2034 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2035 return true; 2036 default: 2037 break; 2038 } 2039 return false; 2040 } 2041 2042 // CSRK Lookup 2043 static bool sm_run_csrk(void){ 2044 btstack_linked_list_iterator_t it; 2045 2046 // -- if csrk lookup ready, find connection that require csrk lookup 2047 if (sm_address_resolution_idle()){ 2048 hci_connections_get_iterator(&it); 2049 while(btstack_linked_list_iterator_has_next(&it)){ 2050 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2051 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2052 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2053 // and start lookup 2054 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); 2055 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2056 break; 2057 } 2058 } 2059 } 2060 2061 // -- if csrk lookup ready, resolved addresses for received addresses 2062 if (sm_address_resolution_idle()) { 2063 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2064 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2065 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2066 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2067 btstack_memory_sm_lookup_entry_free(entry); 2068 } 2069 } 2070 2071 // -- Continue with CSRK device lookup by public or resolvable private address 2072 if (!sm_address_resolution_idle()){ 2073 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2074 while (sm_address_resolution_test < le_device_db_max_count()){ 2075 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2076 bd_addr_t addr; 2077 sm_key_t irk; 2078 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2079 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2080 2081 // skip unused entries 2082 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2083 sm_address_resolution_test++; 2084 continue; 2085 } 2086 2087 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2088 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2089 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2090 break; 2091 } 2092 2093 // if connection type is public, it must be a different one 2094 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2095 sm_address_resolution_test++; 2096 continue; 2097 } 2098 2099 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2100 2101 log_info("LE Device Lookup: calculate AH"); 2102 log_info_key("IRK", irk); 2103 2104 (void)memcpy(sm_aes128_key, irk, 16); 2105 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2106 sm_address_resolution_ah_calculation_active = 1; 2107 sm_aes128_state = SM_AES128_ACTIVE; 2108 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2109 return true; 2110 } 2111 2112 if (sm_address_resolution_test >= le_device_db_max_count()){ 2113 log_info("LE Device Lookup: not found"); 2114 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2115 } 2116 } 2117 return false; 2118 } 2119 2120 // SC OOB 2121 static bool sm_run_oob(void){ 2122 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2123 switch (sm_sc_oob_state){ 2124 case SM_SC_OOB_W2_CALC_CONFIRM: 2125 if (!sm_cmac_ready()) break; 2126 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2127 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2128 return true; 2129 default: 2130 break; 2131 } 2132 #endif 2133 return false; 2134 } 2135 2136 // handle basic actions that don't requires the full context 2137 static bool sm_run_basic(void){ 2138 btstack_linked_list_iterator_t it; 2139 hci_connections_get_iterator(&it); 2140 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2141 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2142 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2143 switch(sm_connection->sm_engine_state){ 2144 // responder side 2145 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2146 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2147 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2148 return true; 2149 2150 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2151 case SM_SC_RECEIVED_LTK_REQUEST: 2152 switch (sm_connection->sm_irk_lookup_state){ 2153 case IRK_LOOKUP_FAILED: 2154 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2155 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2156 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2157 return true; 2158 default: 2159 break; 2160 } 2161 break; 2162 #endif 2163 default: 2164 break; 2165 } 2166 } 2167 return false; 2168 } 2169 2170 static void sm_run_activate_connection(void){ 2171 // Find connections that requires setup context and make active if no other is locked 2172 btstack_linked_list_iterator_t it; 2173 hci_connections_get_iterator(&it); 2174 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2175 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2176 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2177 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2178 int done = 1; 2179 int err; 2180 UNUSED(err); 2181 2182 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2183 // assert ec key is ready 2184 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2185 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2186 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2187 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2188 sm_ec_generate_new_key(); 2189 } 2190 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2191 continue; 2192 } 2193 } 2194 #endif 2195 2196 switch (sm_connection->sm_engine_state) { 2197 #ifdef ENABLE_LE_PERIPHERAL 2198 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2199 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2200 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2201 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2202 case SM_SC_RECEIVED_LTK_REQUEST: 2203 #endif 2204 #endif 2205 #ifdef ENABLE_LE_CENTRAL 2206 case SM_INITIATOR_PH0_HAS_LTK: 2207 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2208 #endif 2209 // just lock context 2210 break; 2211 default: 2212 done = 0; 2213 break; 2214 } 2215 if (done){ 2216 sm_active_connection_handle = sm_connection->sm_handle; 2217 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); 2218 } 2219 } 2220 } 2221 2222 static void sm_run(void){ 2223 2224 // assert that stack has already bootet 2225 if (hci_get_state() != HCI_STATE_WORKING) return; 2226 2227 // assert that we can send at least commands 2228 if (!hci_can_send_command_packet_now()) return; 2229 2230 // pause until IR/ER are ready 2231 if (sm_persistent_keys_random_active) return; 2232 2233 bool done; 2234 2235 // 2236 // non-connection related behaviour 2237 // 2238 2239 done = sm_run_dpkg(); 2240 if (done) return; 2241 2242 done = sm_run_rau(); 2243 if (done) return; 2244 2245 done = sm_run_csrk(); 2246 if (done) return; 2247 2248 done = sm_run_oob(); 2249 if (done) return; 2250 2251 // assert that we can send at least commands - cmd might have been sent by crypto engine 2252 if (!hci_can_send_command_packet_now()) return; 2253 2254 // handle basic actions that don't requires the full context 2255 done = sm_run_basic(); 2256 if (done) return; 2257 2258 // 2259 // active connection handling 2260 // -- use loop to handle next connection if lock on setup context is released 2261 2262 while (true) { 2263 2264 sm_run_activate_connection(); 2265 2266 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2267 2268 // 2269 // active connection handling 2270 // 2271 2272 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2273 if (!connection) { 2274 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2275 return; 2276 } 2277 2278 // assert that we could send a SM PDU - not needed for all of the following 2279 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2280 log_info("cannot send now, requesting can send now event"); 2281 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2282 return; 2283 } 2284 2285 // send keypress notifications 2286 if (setup->sm_keypress_notification){ 2287 int i; 2288 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2289 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2290 uint8_t action = 0; 2291 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2292 if (flags & (1u<<i)){ 2293 int clear_flag = 1; 2294 switch (i){ 2295 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2296 case SM_KEYPRESS_PASSKEY_CLEARED: 2297 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2298 default: 2299 break; 2300 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2301 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2302 num_actions--; 2303 clear_flag = num_actions == 0u; 2304 break; 2305 } 2306 if (clear_flag){ 2307 flags &= ~(1<<i); 2308 } 2309 action = i; 2310 break; 2311 } 2312 } 2313 setup->sm_keypress_notification = (num_actions << 5) | flags; 2314 2315 // send keypress notification 2316 uint8_t buffer[2]; 2317 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2318 buffer[1] = action; 2319 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2320 2321 // try 2322 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2323 return; 2324 } 2325 2326 int key_distribution_flags; 2327 UNUSED(key_distribution_flags); 2328 int err; 2329 UNUSED(err); 2330 2331 log_info("sm_run: state %u", connection->sm_engine_state); 2332 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2333 log_info("sm_run // cannot send"); 2334 } 2335 switch (connection->sm_engine_state){ 2336 2337 // general 2338 case SM_GENERAL_SEND_PAIRING_FAILED: { 2339 uint8_t buffer[2]; 2340 buffer[0] = SM_CODE_PAIRING_FAILED; 2341 buffer[1] = setup->sm_pairing_failed_reason; 2342 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2343 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2344 sm_pairing_complete(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2345 sm_done_for_handle(connection->sm_handle); 2346 break; 2347 } 2348 2349 // secure connections, initiator + responding states 2350 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2351 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2352 if (!sm_cmac_ready()) break; 2353 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2354 sm_sc_calculate_local_confirm(connection); 2355 break; 2356 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2357 if (!sm_cmac_ready()) break; 2358 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2359 sm_sc_calculate_remote_confirm(connection); 2360 break; 2361 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2362 if (!sm_cmac_ready()) break; 2363 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2364 sm_sc_calculate_f6_for_dhkey_check(connection); 2365 break; 2366 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2367 if (!sm_cmac_ready()) break; 2368 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2369 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2370 break; 2371 case SM_SC_W2_CALCULATE_F5_SALT: 2372 if (!sm_cmac_ready()) break; 2373 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2374 f5_calculate_salt(connection); 2375 break; 2376 case SM_SC_W2_CALCULATE_F5_MACKEY: 2377 if (!sm_cmac_ready()) break; 2378 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2379 f5_calculate_mackey(connection); 2380 break; 2381 case SM_SC_W2_CALCULATE_F5_LTK: 2382 if (!sm_cmac_ready()) break; 2383 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2384 f5_calculate_ltk(connection); 2385 break; 2386 case SM_SC_W2_CALCULATE_G2: 2387 if (!sm_cmac_ready()) break; 2388 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2389 g2_calculate(connection); 2390 break; 2391 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2392 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2393 if (!sm_cmac_ready()) break; 2394 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2395 h6_calculate_ilk(connection); 2396 break; 2397 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2398 if (!sm_cmac_ready()) break; 2399 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2400 h6_calculate_br_edr_link_key(connection); 2401 break; 2402 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2403 if (!sm_cmac_ready()) break; 2404 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2405 h7_calculate_ilk(connection); 2406 break; 2407 #endif 2408 #endif 2409 2410 #ifdef ENABLE_LE_CENTRAL 2411 // initiator side 2412 2413 case SM_INITIATOR_PH0_HAS_LTK: { 2414 sm_reset_setup(); 2415 sm_load_security_info(connection); 2416 2417 sm_key_t peer_ltk_flipped; 2418 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2419 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2420 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2421 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2422 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2423 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2424 return; 2425 } 2426 2427 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2428 sm_reset_setup(); 2429 sm_init_setup(connection); 2430 sm_timeout_start(connection); 2431 2432 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2433 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2434 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2435 sm_timeout_reset(connection); 2436 break; 2437 #endif 2438 2439 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2440 2441 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2442 int trigger_user_response = 0; 2443 int trigger_start_calculating_local_confirm = 0; 2444 uint8_t buffer[65]; 2445 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2446 // 2447 reverse_256(&ec_q[0], &buffer[1]); 2448 reverse_256(&ec_q[32], &buffer[33]); 2449 2450 #ifdef ENABLE_TESTING_SUPPORT 2451 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2452 log_info("testing_support: invalidating public key"); 2453 // flip single bit of public key coordinate 2454 buffer[1] ^= 1; 2455 } 2456 #endif 2457 2458 // stk generation method 2459 // passkey entry: notify app to show passkey or to request passkey 2460 switch (setup->sm_stk_generation_method){ 2461 case JUST_WORKS: 2462 case NUMERIC_COMPARISON: 2463 if (IS_RESPONDER(connection->sm_role)){ 2464 // responder 2465 trigger_start_calculating_local_confirm = 1; 2466 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2467 } else { 2468 // initiator 2469 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2470 } 2471 break; 2472 case PK_INIT_INPUT: 2473 case PK_RESP_INPUT: 2474 case PK_BOTH_INPUT: 2475 // use random TK for display 2476 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2477 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2478 setup->sm_passkey_bit = 0; 2479 2480 if (IS_RESPONDER(connection->sm_role)){ 2481 // responder 2482 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2483 } else { 2484 // initiator 2485 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2486 } 2487 trigger_user_response = 1; 2488 break; 2489 case OOB: 2490 if (IS_RESPONDER(connection->sm_role)){ 2491 // responder 2492 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2493 } else { 2494 // initiator 2495 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2496 } 2497 break; 2498 default: 2499 btstack_assert(false); 2500 break; 2501 } 2502 2503 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2504 sm_timeout_reset(connection); 2505 2506 // trigger user response and calc confirm after sending pdu 2507 if (trigger_user_response){ 2508 sm_trigger_user_response(connection); 2509 } 2510 if (trigger_start_calculating_local_confirm){ 2511 sm_sc_start_calculating_local_confirm(connection); 2512 } 2513 break; 2514 } 2515 case SM_SC_SEND_CONFIRMATION: { 2516 uint8_t buffer[17]; 2517 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2518 reverse_128(setup->sm_local_confirm, &buffer[1]); 2519 if (IS_RESPONDER(connection->sm_role)){ 2520 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2521 } else { 2522 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2523 } 2524 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2525 sm_timeout_reset(connection); 2526 break; 2527 } 2528 case SM_SC_SEND_PAIRING_RANDOM: { 2529 uint8_t buffer[17]; 2530 buffer[0] = SM_CODE_PAIRING_RANDOM; 2531 reverse_128(setup->sm_local_nonce, &buffer[1]); 2532 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2533 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2534 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2535 if (IS_RESPONDER(connection->sm_role)){ 2536 // responder 2537 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2538 } else { 2539 // initiator 2540 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2541 } 2542 } else { 2543 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2544 if (IS_RESPONDER(connection->sm_role)){ 2545 // responder 2546 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2547 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2548 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2549 } else { 2550 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2551 sm_sc_prepare_dhkey_check(connection); 2552 } 2553 } else { 2554 // initiator 2555 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2556 } 2557 } 2558 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2559 sm_timeout_reset(connection); 2560 break; 2561 } 2562 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2563 uint8_t buffer[17]; 2564 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2565 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2566 2567 if (IS_RESPONDER(connection->sm_role)){ 2568 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2569 } else { 2570 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2571 } 2572 2573 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2574 sm_timeout_reset(connection); 2575 break; 2576 } 2577 2578 #endif 2579 2580 #ifdef ENABLE_LE_PERIPHERAL 2581 2582 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2583 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2584 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2585 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2586 sm_timeout_start(connection); 2587 break; 2588 } 2589 2590 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2591 case SM_SC_RECEIVED_LTK_REQUEST: 2592 switch (connection->sm_irk_lookup_state){ 2593 case IRK_LOOKUP_SUCCEEDED: 2594 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2595 // start using context by loading security info 2596 sm_reset_setup(); 2597 sm_load_security_info(connection); 2598 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2599 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2600 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2601 sm_trigger_run(); 2602 break; 2603 } 2604 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2605 connection->sm_engine_state = SM_RESPONDER_IDLE; 2606 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2607 return; 2608 default: 2609 // just wait until IRK lookup is completed 2610 break; 2611 } 2612 break; 2613 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2614 2615 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2616 sm_reset_setup(); 2617 sm_init_setup(connection); 2618 // recover pairing request 2619 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2620 err = sm_stk_generation_init(connection); 2621 2622 #ifdef ENABLE_TESTING_SUPPORT 2623 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2624 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2625 err = test_pairing_failure; 2626 } 2627 #endif 2628 if (err){ 2629 setup->sm_pairing_failed_reason = err; 2630 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2631 sm_trigger_run(); 2632 break; 2633 } 2634 2635 sm_timeout_start(connection); 2636 2637 // generate random number first, if we need to show passkey, otherwise send response 2638 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2639 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2640 break; 2641 } 2642 2643 /* fall through */ 2644 2645 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2646 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2647 2648 // start with initiator key dist flags 2649 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2650 2651 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2652 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2653 if (setup->sm_use_secure_connections){ 2654 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2655 } 2656 #endif 2657 // setup in response 2658 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); 2659 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); 2660 2661 // update key distribution after ENC was dropped 2662 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2663 2664 if (setup->sm_use_secure_connections){ 2665 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2666 } else { 2667 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2668 } 2669 2670 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2671 sm_timeout_reset(connection); 2672 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2673 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2674 sm_trigger_user_response(connection); 2675 } 2676 return; 2677 #endif 2678 2679 case SM_PH2_SEND_PAIRING_RANDOM: { 2680 uint8_t buffer[17]; 2681 buffer[0] = SM_CODE_PAIRING_RANDOM; 2682 reverse_128(setup->sm_local_random, &buffer[1]); 2683 if (IS_RESPONDER(connection->sm_role)){ 2684 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2685 } else { 2686 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2687 } 2688 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2689 sm_timeout_reset(connection); 2690 break; 2691 } 2692 2693 case SM_PH2_C1_GET_ENC_A: 2694 // already busy? 2695 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2696 // calculate confirm using aes128 engine - step 1 2697 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); 2698 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2699 sm_aes128_state = SM_AES128_ACTIVE; 2700 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); 2701 break; 2702 2703 case SM_PH2_C1_GET_ENC_C: 2704 // already busy? 2705 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2706 // calculate m_confirm using aes128 engine - step 1 2707 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); 2708 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2709 sm_aes128_state = SM_AES128_ACTIVE; 2710 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); 2711 break; 2712 2713 case SM_PH2_CALC_STK: 2714 // already busy? 2715 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2716 // calculate STK 2717 if (IS_RESPONDER(connection->sm_role)){ 2718 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2719 } else { 2720 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2721 } 2722 connection->sm_engine_state = SM_PH2_W4_STK; 2723 sm_aes128_state = SM_AES128_ACTIVE; 2724 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); 2725 break; 2726 2727 case SM_PH3_Y_GET_ENC: 2728 // already busy? 2729 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2730 // PH3B2 - calculate Y from - enc 2731 2732 // dm helper (was sm_dm_r_prime) 2733 // r' = padding || r 2734 // r - 64 bit value 2735 memset(&sm_aes128_plaintext[0], 0, 8); 2736 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2737 2738 // Y = dm(DHK, Rand) 2739 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2740 sm_aes128_state = SM_AES128_ACTIVE; 2741 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); 2742 break; 2743 2744 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2745 uint8_t buffer[17]; 2746 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2747 reverse_128(setup->sm_local_confirm, &buffer[1]); 2748 if (IS_RESPONDER(connection->sm_role)){ 2749 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2750 } else { 2751 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2752 } 2753 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2754 sm_timeout_reset(connection); 2755 return; 2756 } 2757 #ifdef ENABLE_LE_PERIPHERAL 2758 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2759 sm_key_t stk_flipped; 2760 reverse_128(setup->sm_ltk, stk_flipped); 2761 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2762 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2763 return; 2764 } 2765 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2766 sm_key_t ltk_flipped; 2767 reverse_128(setup->sm_ltk, ltk_flipped); 2768 connection->sm_engine_state = SM_RESPONDER_IDLE; 2769 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2770 sm_done_for_handle(connection->sm_handle); 2771 return; 2772 } 2773 2774 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2775 // already busy? 2776 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2777 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2778 2779 sm_reset_setup(); 2780 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2781 2782 // dm helper (was sm_dm_r_prime) 2783 // r' = padding || r 2784 // r - 64 bit value 2785 memset(&sm_aes128_plaintext[0], 0, 8); 2786 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2787 2788 // Y = dm(DHK, Rand) 2789 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2790 sm_aes128_state = SM_AES128_ACTIVE; 2791 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); 2792 return; 2793 #endif 2794 #ifdef ENABLE_LE_CENTRAL 2795 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2796 sm_key_t stk_flipped; 2797 reverse_128(setup->sm_ltk, stk_flipped); 2798 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2799 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2800 return; 2801 } 2802 #endif 2803 2804 case SM_PH3_DISTRIBUTE_KEYS: 2805 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2806 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2807 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2808 uint8_t buffer[17]; 2809 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2810 reverse_128(setup->sm_ltk, &buffer[1]); 2811 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2812 sm_timeout_reset(connection); 2813 return; 2814 } 2815 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2816 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2817 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2818 uint8_t buffer[11]; 2819 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2820 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2821 reverse_64(setup->sm_local_rand, &buffer[3]); 2822 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2823 sm_timeout_reset(connection); 2824 return; 2825 } 2826 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2827 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2828 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2829 uint8_t buffer[17]; 2830 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2831 reverse_128(sm_persistent_irk, &buffer[1]); 2832 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2833 sm_timeout_reset(connection); 2834 return; 2835 } 2836 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2837 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2838 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2839 bd_addr_t local_address; 2840 uint8_t buffer[8]; 2841 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2842 switch (gap_random_address_get_mode()){ 2843 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2844 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2845 // public or static random 2846 gap_le_get_own_address(&buffer[1], local_address); 2847 break; 2848 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2849 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2850 // fallback to public 2851 gap_local_bd_addr(local_address); 2852 buffer[1] = 0; 2853 break; 2854 default: 2855 btstack_assert(false); 2856 break; 2857 } 2858 reverse_bd_addr(local_address, &buffer[2]); 2859 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2860 sm_timeout_reset(connection); 2861 return; 2862 } 2863 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2864 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2865 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2866 2867 #ifdef ENABLE_LE_SIGNED_WRITE 2868 // hack to reproduce test runs 2869 if (test_use_fixed_local_csrk){ 2870 memset(setup->sm_local_csrk, 0xcc, 16); 2871 } 2872 2873 // store local CSRK 2874 if (setup->sm_le_device_index >= 0){ 2875 log_info("sm: store local CSRK"); 2876 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2877 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2878 } 2879 #endif 2880 2881 uint8_t buffer[17]; 2882 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2883 reverse_128(setup->sm_local_csrk, &buffer[1]); 2884 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2885 sm_timeout_reset(connection); 2886 return; 2887 } 2888 2889 // keys are sent 2890 if (IS_RESPONDER(connection->sm_role)){ 2891 // slave -> receive master keys if any 2892 if (sm_key_distribution_all_received(connection)){ 2893 sm_key_distribution_handle_all_received(connection); 2894 connection->sm_engine_state = SM_RESPONDER_IDLE; 2895 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2896 sm_done_for_handle(connection->sm_handle); 2897 } else { 2898 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2899 } 2900 } else { 2901 sm_master_pairing_success(connection); 2902 } 2903 break; 2904 2905 default: 2906 break; 2907 } 2908 2909 // check again if active connection was released 2910 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2911 } 2912 } 2913 2914 // sm_aes128_state stays active 2915 static void sm_handle_encryption_result_enc_a(void *arg){ 2916 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2917 sm_aes128_state = SM_AES128_IDLE; 2918 2919 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2920 if (connection == NULL) return; 2921 2922 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2923 sm_aes128_state = SM_AES128_ACTIVE; 2924 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); 2925 } 2926 2927 static void sm_handle_encryption_result_enc_b(void *arg){ 2928 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2929 sm_aes128_state = SM_AES128_IDLE; 2930 2931 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2932 if (connection == NULL) return; 2933 2934 log_info_key("c1!", setup->sm_local_confirm); 2935 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2936 sm_trigger_run(); 2937 } 2938 2939 // sm_aes128_state stays active 2940 static void sm_handle_encryption_result_enc_c(void *arg){ 2941 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2942 sm_aes128_state = SM_AES128_IDLE; 2943 2944 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2945 if (connection == NULL) return; 2946 2947 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2948 sm_aes128_state = SM_AES128_ACTIVE; 2949 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); 2950 } 2951 2952 static void sm_handle_encryption_result_enc_d(void * arg){ 2953 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2954 sm_aes128_state = SM_AES128_IDLE; 2955 2956 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2957 if (connection == NULL) return; 2958 2959 log_info_key("c1!", sm_aes128_ciphertext); 2960 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2961 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2962 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2963 sm_trigger_run(); 2964 return; 2965 } 2966 if (IS_RESPONDER(connection->sm_role)){ 2967 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2968 sm_trigger_run(); 2969 } else { 2970 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2971 sm_aes128_state = SM_AES128_ACTIVE; 2972 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); 2973 } 2974 } 2975 2976 static void sm_handle_encryption_result_enc_stk(void *arg){ 2977 sm_aes128_state = SM_AES128_IDLE; 2978 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2979 2980 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2981 if (connection == NULL) return; 2982 2983 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2984 log_info_key("stk", setup->sm_ltk); 2985 if (IS_RESPONDER(connection->sm_role)){ 2986 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2987 } else { 2988 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2989 } 2990 sm_trigger_run(); 2991 } 2992 2993 // sm_aes128_state stays active 2994 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2995 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2996 sm_aes128_state = SM_AES128_IDLE; 2997 2998 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2999 if (connection == NULL) return; 3000 3001 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3002 log_info_hex16("y", setup->sm_local_y); 3003 // PH3B3 - calculate EDIV 3004 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3005 log_info_hex16("ediv", setup->sm_local_ediv); 3006 // PH3B4 - calculate LTK - enc 3007 // LTK = d1(ER, DIV, 0)) 3008 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3009 sm_aes128_state = SM_AES128_ACTIVE; 3010 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); 3011 } 3012 3013 #ifdef ENABLE_LE_PERIPHERAL 3014 // sm_aes128_state stays active 3015 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3016 sm_aes128_state = SM_AES128_IDLE; 3017 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3018 3019 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3020 if (connection == NULL) return; 3021 3022 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3023 log_info_hex16("y", setup->sm_local_y); 3024 3025 // PH3B3 - calculate DIV 3026 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3027 log_info_hex16("ediv", setup->sm_local_ediv); 3028 // PH3B4 - calculate LTK - enc 3029 // LTK = d1(ER, DIV, 0)) 3030 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3031 sm_aes128_state = SM_AES128_ACTIVE; 3032 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); 3033 } 3034 #endif 3035 3036 // sm_aes128_state stays active 3037 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3038 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3039 sm_aes128_state = SM_AES128_IDLE; 3040 3041 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3042 if (connection == NULL) return; 3043 3044 log_info_key("ltk", setup->sm_ltk); 3045 // calc CSRK next 3046 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3047 sm_aes128_state = SM_AES128_ACTIVE; 3048 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); 3049 } 3050 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3051 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3052 // requirements to derive link key from LE: 3053 // - use secure connections 3054 if (setup->sm_use_secure_connections == 0) return false; 3055 // - bonding needs to be enabled: 3056 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; 3057 if (!bonding_enabled) return false; 3058 // - need identity address 3059 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3060 if (!have_identity_address_info) return false; 3061 // - 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) 3062 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3063 // If SC is authenticated, we consider it safe to overwrite a stored key. 3064 // 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. 3065 uint8_t link_key[16]; 3066 link_key_type_t link_key_type; 3067 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3068 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3069 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3070 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3071 return false; 3072 } 3073 // get started (all of the above are true) 3074 return true; 3075 #else 3076 UNUSED(sm_connection); 3077 return false; 3078 #endif 3079 } 3080 3081 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3082 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3083 sm_aes128_state = SM_AES128_IDLE; 3084 3085 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3086 if (connection == NULL) return; 3087 3088 sm_aes128_state = SM_AES128_IDLE; 3089 log_info_key("csrk", setup->sm_local_csrk); 3090 if (setup->sm_key_distribution_send_set){ 3091 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3092 } else { 3093 // no keys to send, just continue 3094 if (IS_RESPONDER(connection->sm_role)){ 3095 // slave -> receive master keys 3096 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3097 } else { 3098 if (sm_ctkd_from_le(connection)){ 3099 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; 3100 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3101 } else { 3102 sm_master_pairing_success(connection); 3103 } 3104 } 3105 } 3106 sm_trigger_run(); 3107 } 3108 3109 #ifdef ENABLE_LE_PERIPHERAL 3110 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3111 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3112 sm_aes128_state = SM_AES128_IDLE; 3113 3114 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3115 if (connection == NULL) return; 3116 3117 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3118 log_info_key("ltk", setup->sm_ltk); 3119 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3120 sm_trigger_run(); 3121 } 3122 #endif 3123 3124 static void sm_handle_encryption_result_address_resolution(void *arg){ 3125 UNUSED(arg); 3126 sm_aes128_state = SM_AES128_IDLE; 3127 3128 sm_address_resolution_ah_calculation_active = 0; 3129 // compare calulated address against connecting device 3130 uint8_t * hash = &sm_aes128_ciphertext[13]; 3131 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3132 log_info("LE Device Lookup: matched resolvable private address"); 3133 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3134 sm_trigger_run(); 3135 return; 3136 } 3137 // no match, try next 3138 sm_address_resolution_test++; 3139 sm_trigger_run(); 3140 } 3141 3142 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3143 UNUSED(arg); 3144 sm_aes128_state = SM_AES128_IDLE; 3145 3146 log_info_key("irk", sm_persistent_irk); 3147 dkg_state = DKG_CALC_DHK; 3148 sm_trigger_run(); 3149 } 3150 3151 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3152 UNUSED(arg); 3153 sm_aes128_state = SM_AES128_IDLE; 3154 3155 log_info_key("dhk", sm_persistent_dhk); 3156 dkg_state = DKG_READY; 3157 sm_trigger_run(); 3158 } 3159 3160 static void sm_handle_encryption_result_rau(void *arg){ 3161 UNUSED(arg); 3162 sm_aes128_state = SM_AES128_IDLE; 3163 3164 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3165 rau_state = RAU_SET_ADDRESS; 3166 sm_trigger_run(); 3167 } 3168 3169 static void sm_handle_random_result_rau(void * arg){ 3170 UNUSED(arg); 3171 // non-resolvable vs. resolvable 3172 switch (gap_random_adress_type){ 3173 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3174 // resolvable: use random as prand and calc address hash 3175 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3176 sm_random_address[0u] &= 0x3fu; 3177 sm_random_address[0u] |= 0x40u; 3178 rau_state = RAU_GET_ENC; 3179 break; 3180 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3181 default: 3182 // "The two most significant bits of the address shall be equal to ‘0’"" 3183 sm_random_address[0u] &= 0x3fu; 3184 rau_state = RAU_SET_ADDRESS; 3185 break; 3186 } 3187 sm_trigger_run(); 3188 } 3189 3190 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3191 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3192 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3193 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3194 if (connection == NULL) return; 3195 3196 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3197 sm_trigger_run(); 3198 } 3199 3200 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3201 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3202 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3203 if (connection == NULL) return; 3204 3205 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3206 sm_trigger_run(); 3207 } 3208 #endif 3209 3210 static void sm_handle_random_result_ph2_random(void * arg){ 3211 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3212 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3213 if (connection == NULL) return; 3214 3215 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3216 sm_trigger_run(); 3217 } 3218 3219 static void sm_handle_random_result_ph2_tk(void * arg){ 3220 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3221 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3222 if (connection == NULL) return; 3223 3224 sm_reset_tk(); 3225 uint32_t tk; 3226 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3227 // map random to 0-999999 without speding much cycles on a modulus operation 3228 tk = little_endian_read_32(sm_random_data,0); 3229 tk = tk & 0xfffff; // 1048575 3230 if (tk >= 999999u){ 3231 tk = tk - 999999u; 3232 } 3233 } else { 3234 // override with pre-defined passkey 3235 tk = sm_fixed_passkey_in_display_role; 3236 } 3237 big_endian_store_32(setup->sm_tk, 12, tk); 3238 if (IS_RESPONDER(connection->sm_role)){ 3239 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3240 } else { 3241 if (setup->sm_use_secure_connections){ 3242 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3243 } else { 3244 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3245 sm_trigger_user_response(connection); 3246 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3247 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3248 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); 3249 } 3250 } 3251 } 3252 sm_trigger_run(); 3253 } 3254 3255 static void sm_handle_random_result_ph3_div(void * arg){ 3256 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3257 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3258 if (connection == NULL) return; 3259 3260 // use 16 bit from random value as div 3261 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3262 log_info_hex16("div", setup->sm_local_div); 3263 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3264 sm_trigger_run(); 3265 } 3266 3267 static void sm_handle_random_result_ph3_random(void * arg){ 3268 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3269 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3270 if (connection == NULL) return; 3271 3272 reverse_64(sm_random_data, setup->sm_local_rand); 3273 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3274 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3275 // no db for authenticated flag hack: store flag in bit 4 of LSB 3276 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3277 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3278 } 3279 static void sm_validate_er_ir(void){ 3280 // warn about default ER/IR 3281 int warning = 0; 3282 if (sm_ir_is_default()){ 3283 warning = 1; 3284 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3285 } 3286 if (sm_er_is_default()){ 3287 warning = 1; 3288 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3289 } 3290 if (warning) { 3291 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3292 } 3293 } 3294 3295 static void sm_handle_random_result_ir(void *arg){ 3296 sm_persistent_keys_random_active = 0; 3297 if (arg){ 3298 // key generated, store in tlv 3299 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3300 log_info("Generated IR key. Store in TLV status: %d", status); 3301 UNUSED(status); 3302 } 3303 log_info_key("IR", sm_persistent_ir); 3304 dkg_state = DKG_CALC_IRK; 3305 3306 if (test_use_fixed_local_irk){ 3307 log_info_key("IRK", sm_persistent_irk); 3308 dkg_state = DKG_CALC_DHK; 3309 } 3310 3311 sm_trigger_run(); 3312 } 3313 3314 static void sm_handle_random_result_er(void *arg){ 3315 sm_persistent_keys_random_active = 0; 3316 if (arg){ 3317 // key generated, store in tlv 3318 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3319 log_info("Generated ER key. Store in TLV status: %d", status); 3320 UNUSED(status); 3321 } 3322 log_info_key("ER", sm_persistent_er); 3323 3324 // try load ir 3325 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3326 if (key_size == 16){ 3327 // ok, let's continue 3328 log_info("IR from TLV"); 3329 sm_handle_random_result_ir( NULL ); 3330 } else { 3331 // invalid, generate new random one 3332 sm_persistent_keys_random_active = 1; 3333 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3334 } 3335 } 3336 3337 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3338 3339 UNUSED(channel); // ok: there is no channel 3340 UNUSED(size); // ok: fixed format HCI events 3341 3342 sm_connection_t * sm_conn; 3343 hci_con_handle_t con_handle; 3344 uint8_t status; 3345 switch (packet_type) { 3346 3347 case HCI_EVENT_PACKET: 3348 switch (hci_event_packet_get_type(packet)) { 3349 3350 case BTSTACK_EVENT_STATE: 3351 // bt stack activated, get started 3352 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3353 log_info("HCI Working!"); 3354 3355 // setup IR/ER with TLV 3356 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3357 if (sm_tlv_impl){ 3358 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3359 if (key_size == 16){ 3360 // ok, let's continue 3361 log_info("ER from TLV"); 3362 sm_handle_random_result_er( NULL ); 3363 } else { 3364 // invalid, generate random one 3365 sm_persistent_keys_random_active = 1; 3366 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3367 } 3368 } else { 3369 sm_validate_er_ir(); 3370 dkg_state = DKG_CALC_IRK; 3371 3372 if (test_use_fixed_local_irk){ 3373 log_info_key("IRK", sm_persistent_irk); 3374 dkg_state = DKG_CALC_DHK; 3375 } 3376 } 3377 3378 // restart random address updates after power cycle 3379 gap_random_address_set_mode(gap_random_adress_type); 3380 } 3381 break; 3382 3383 case HCI_EVENT_LE_META: 3384 switch (packet[2]) { 3385 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3386 3387 log_info("sm: connected"); 3388 3389 if (packet[3]) return; // connection failed 3390 3391 con_handle = little_endian_read_16(packet, 4); 3392 sm_conn = sm_get_connection_for_handle(con_handle); 3393 if (!sm_conn) break; 3394 3395 sm_conn->sm_handle = con_handle; 3396 sm_conn->sm_role = packet[6]; 3397 sm_conn->sm_peer_addr_type = packet[7]; 3398 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3399 3400 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3401 3402 // reset security properties 3403 sm_conn->sm_connection_encrypted = 0; 3404 sm_conn->sm_connection_authenticated = 0; 3405 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3406 sm_conn->sm_le_db_index = -1; 3407 3408 // prepare CSRK lookup (does not involve setup) 3409 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3410 3411 // just connected -> everything else happens in sm_run() 3412 if (IS_RESPONDER(sm_conn->sm_role)){ 3413 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3414 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3415 if (sm_slave_request_security) { 3416 // request security if requested by app 3417 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3418 } else { 3419 // otherwise, wait for pairing request 3420 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3421 } 3422 } 3423 break; 3424 } else { 3425 // master 3426 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3427 } 3428 break; 3429 3430 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3431 con_handle = little_endian_read_16(packet, 3); 3432 sm_conn = sm_get_connection_for_handle(con_handle); 3433 if (!sm_conn) break; 3434 3435 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3436 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3437 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3438 break; 3439 } 3440 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3441 // PH2 SEND LTK as we need to exchange keys in PH3 3442 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3443 break; 3444 } 3445 3446 // store rand and ediv 3447 reverse_64(&packet[5], sm_conn->sm_local_rand); 3448 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3449 3450 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3451 // potentially stored LTK is from the master 3452 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3453 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3454 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3455 break; 3456 } 3457 // additionally check if remote is in LE Device DB if requested 3458 switch(sm_conn->sm_irk_lookup_state){ 3459 case IRK_LOOKUP_FAILED: 3460 log_info("LTK Request: device not in device db"); 3461 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3462 break; 3463 case IRK_LOOKUP_SUCCEEDED: 3464 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3465 break; 3466 default: 3467 // wait for irk look doen 3468 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3469 break; 3470 } 3471 break; 3472 } 3473 3474 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3475 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3476 #else 3477 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3478 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3479 #endif 3480 break; 3481 3482 default: 3483 break; 3484 } 3485 break; 3486 3487 case HCI_EVENT_ENCRYPTION_CHANGE: 3488 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3489 sm_conn = sm_get_connection_for_handle(con_handle); 3490 if (!sm_conn) break; 3491 3492 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3493 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3494 sm_conn->sm_actual_encryption_key_size); 3495 log_info("event handler, state %u", sm_conn->sm_engine_state); 3496 3497 switch (sm_conn->sm_engine_state){ 3498 3499 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3500 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3501 if (sm_conn->sm_connection_encrypted) { 3502 status = ERROR_CODE_SUCCESS; 3503 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3504 } else { 3505 status = ERROR_CODE_AUTHENTICATION_FAILURE; 3506 // set state to 'TIMEOUT' to prevent further interaction with this 3507 // also, gap_reconnect_security_setup_active will return true 3508 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 3509 } 3510 3511 // emit re-encryption complete 3512 sm_reencryption_complete(sm_conn, status); 3513 3514 // notify client, if pairing was requested before 3515 if (sm_conn->sm_pairing_requested){ 3516 sm_conn->sm_pairing_requested = 0; 3517 sm_pairing_complete(sm_conn, status, 0); 3518 } 3519 3520 sm_done_for_handle(sm_conn->sm_handle); 3521 3522 // abort/disconnect on authentication failure 3523 if (status == ERROR_CODE_AUTHENTICATION_FAILURE){ 3524 // gap disconnect with authentication failure 3525 hci_disconnect_security_block(con_handle); 3526 } 3527 break; 3528 3529 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3530 if (!sm_conn->sm_connection_encrypted) break; 3531 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3532 if (IS_RESPONDER(sm_conn->sm_role)){ 3533 // slave 3534 if (setup->sm_use_secure_connections){ 3535 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3536 } else { 3537 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); 3538 } 3539 } else { 3540 // master 3541 if (sm_key_distribution_all_received(sm_conn)){ 3542 // skip receiving keys as there are none 3543 sm_key_distribution_handle_all_received(sm_conn); 3544 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); 3545 } else { 3546 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3547 } 3548 } 3549 break; 3550 default: 3551 break; 3552 } 3553 break; 3554 3555 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3556 con_handle = little_endian_read_16(packet, 3); 3557 sm_conn = sm_get_connection_for_handle(con_handle); 3558 if (!sm_conn) break; 3559 3560 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3561 log_info("event handler, state %u", sm_conn->sm_engine_state); 3562 // continue if part of initial pairing 3563 switch (sm_conn->sm_engine_state){ 3564 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3565 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3566 sm_done_for_handle(sm_conn->sm_handle); 3567 break; 3568 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3569 if (IS_RESPONDER(sm_conn->sm_role)){ 3570 // slave 3571 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); 3572 } else { 3573 // master 3574 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3575 } 3576 break; 3577 default: 3578 break; 3579 } 3580 break; 3581 3582 3583 case HCI_EVENT_DISCONNECTION_COMPLETE: 3584 con_handle = little_endian_read_16(packet, 3); 3585 sm_done_for_handle(con_handle); 3586 sm_conn = sm_get_connection_for_handle(con_handle); 3587 if (!sm_conn) break; 3588 3589 // delete stored bonding on disconnect with authentication failure in ph0 3590 if ((sm_conn->sm_role == 0u) 3591 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3592 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3593 le_device_db_remove(sm_conn->sm_le_db_index); 3594 } 3595 3596 // pairing failed, if it was ongoing 3597 switch (sm_conn->sm_engine_state){ 3598 case SM_GENERAL_IDLE: 3599 case SM_INITIATOR_CONNECTED: 3600 case SM_RESPONDER_IDLE: 3601 break; 3602 default: 3603 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3604 break; 3605 } 3606 3607 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3608 sm_conn->sm_handle = 0; 3609 break; 3610 3611 case HCI_EVENT_COMMAND_COMPLETE: 3612 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3613 // set local addr for le device db 3614 bd_addr_t addr; 3615 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3616 le_device_db_set_local_bd_addr(addr); 3617 } 3618 break; 3619 default: 3620 break; 3621 } 3622 break; 3623 default: 3624 break; 3625 } 3626 3627 sm_run(); 3628 } 3629 3630 static inline int sm_calc_actual_encryption_key_size(int other){ 3631 if (other < sm_min_encryption_key_size) return 0; 3632 if (other < sm_max_encryption_key_size) return other; 3633 return sm_max_encryption_key_size; 3634 } 3635 3636 3637 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3638 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3639 switch (method){ 3640 case JUST_WORKS: 3641 case NUMERIC_COMPARISON: 3642 return 1; 3643 default: 3644 return 0; 3645 } 3646 } 3647 // responder 3648 3649 static int sm_passkey_used(stk_generation_method_t method){ 3650 switch (method){ 3651 case PK_RESP_INPUT: 3652 return 1; 3653 default: 3654 return 0; 3655 } 3656 } 3657 3658 static int sm_passkey_entry(stk_generation_method_t method){ 3659 switch (method){ 3660 case PK_RESP_INPUT: 3661 case PK_INIT_INPUT: 3662 case PK_BOTH_INPUT: 3663 return 1; 3664 default: 3665 return 0; 3666 } 3667 } 3668 3669 #endif 3670 3671 /** 3672 * @return ok 3673 */ 3674 static int sm_validate_stk_generation_method(void){ 3675 // check if STK generation method is acceptable by client 3676 switch (setup->sm_stk_generation_method){ 3677 case JUST_WORKS: 3678 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3679 case PK_RESP_INPUT: 3680 case PK_INIT_INPUT: 3681 case PK_BOTH_INPUT: 3682 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3683 case OOB: 3684 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3685 case NUMERIC_COMPARISON: 3686 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3687 default: 3688 return 0; 3689 } 3690 } 3691 3692 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3693 3694 // size of complete sm_pdu used to validate input 3695 static const uint8_t sm_pdu_size[] = { 3696 0, // 0x00 invalid opcode 3697 7, // 0x01 pairing request 3698 7, // 0x02 pairing response 3699 17, // 0x03 pairing confirm 3700 17, // 0x04 pairing random 3701 2, // 0x05 pairing failed 3702 17, // 0x06 encryption information 3703 11, // 0x07 master identification 3704 17, // 0x08 identification information 3705 8, // 0x09 identify address information 3706 17, // 0x0a signing information 3707 2, // 0x0b security request 3708 65, // 0x0c pairing public key 3709 17, // 0x0d pairing dhk check 3710 2, // 0x0e keypress notification 3711 }; 3712 3713 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3714 sm_run(); 3715 } 3716 3717 if (packet_type != SM_DATA_PACKET) return; 3718 if (size == 0u) return; 3719 3720 uint8_t sm_pdu_code = packet[0]; 3721 3722 // validate pdu size 3723 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3724 if (sm_pdu_size[sm_pdu_code] != size) return; 3725 3726 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3727 if (!sm_conn) return; 3728 3729 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3730 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3731 sm_done_for_handle(con_handle); 3732 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3733 return; 3734 } 3735 3736 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3737 3738 int err; 3739 UNUSED(err); 3740 3741 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3742 uint8_t buffer[5]; 3743 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3744 buffer[1] = 3; 3745 little_endian_store_16(buffer, 2, con_handle); 3746 buffer[4] = packet[1]; 3747 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3748 return; 3749 } 3750 3751 switch (sm_conn->sm_engine_state){ 3752 3753 // a sm timeout requires a new physical connection 3754 case SM_GENERAL_TIMEOUT: 3755 return; 3756 3757 #ifdef ENABLE_LE_CENTRAL 3758 3759 // Initiator 3760 case SM_INITIATOR_CONNECTED: 3761 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3762 sm_pdu_received_in_wrong_state(sm_conn); 3763 break; 3764 } 3765 3766 // IRK complete? 3767 int have_ltk; 3768 uint8_t ltk[16]; 3769 switch (sm_conn->sm_irk_lookup_state){ 3770 case IRK_LOOKUP_FAILED: 3771 // start pairing 3772 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3773 break; 3774 case IRK_LOOKUP_SUCCEEDED: 3775 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3776 have_ltk = !sm_is_null_key(ltk); 3777 log_info("central: security request - have_ltk %u", have_ltk); 3778 if (have_ltk){ 3779 // start re-encrypt 3780 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3781 } else { 3782 // start pairing 3783 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3784 } 3785 break; 3786 default: 3787 // otherwise, store security request 3788 sm_conn->sm_security_request_received = 1; 3789 break; 3790 } 3791 break; 3792 3793 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3794 // Core 5, Vol 3, Part H, 2.4.6: 3795 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3796 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3797 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3798 log_info("Ignoring Security Request"); 3799 break; 3800 } 3801 3802 // all other pdus are incorrect 3803 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3804 sm_pdu_received_in_wrong_state(sm_conn); 3805 break; 3806 } 3807 3808 // store pairing request 3809 (void)memcpy(&setup->sm_s_pres, packet, 3810 sizeof(sm_pairing_packet_t)); 3811 err = sm_stk_generation_init(sm_conn); 3812 3813 #ifdef ENABLE_TESTING_SUPPORT 3814 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3815 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3816 err = test_pairing_failure; 3817 } 3818 #endif 3819 3820 if (err){ 3821 setup->sm_pairing_failed_reason = err; 3822 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3823 break; 3824 } 3825 3826 // generate random number first, if we need to show passkey 3827 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3828 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); 3829 break; 3830 } 3831 3832 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3833 if (setup->sm_use_secure_connections){ 3834 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3835 if (setup->sm_stk_generation_method == JUST_WORKS){ 3836 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3837 sm_trigger_user_response(sm_conn); 3838 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3839 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3840 } 3841 } else { 3842 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3843 } 3844 break; 3845 } 3846 #endif 3847 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3848 sm_trigger_user_response(sm_conn); 3849 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3850 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3851 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); 3852 } 3853 break; 3854 3855 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3856 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3857 sm_pdu_received_in_wrong_state(sm_conn); 3858 break; 3859 } 3860 3861 // store s_confirm 3862 reverse_128(&packet[1], setup->sm_peer_confirm); 3863 3864 #ifdef ENABLE_TESTING_SUPPORT 3865 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3866 log_info("testing_support: reset confirm value"); 3867 memset(setup->sm_peer_confirm, 0, 16); 3868 } 3869 #endif 3870 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3871 break; 3872 3873 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3874 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3875 sm_pdu_received_in_wrong_state(sm_conn); 3876 break;; 3877 } 3878 3879 // received random value 3880 reverse_128(&packet[1], setup->sm_peer_random); 3881 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3882 break; 3883 #endif 3884 3885 #ifdef ENABLE_LE_PERIPHERAL 3886 // Responder 3887 case SM_RESPONDER_IDLE: 3888 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3889 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3890 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3891 sm_pdu_received_in_wrong_state(sm_conn); 3892 break;; 3893 } 3894 3895 // store pairing request 3896 (void)memcpy(&sm_conn->sm_m_preq, packet, 3897 sizeof(sm_pairing_packet_t)); 3898 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3899 break; 3900 #endif 3901 3902 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3903 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3904 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3905 sm_pdu_received_in_wrong_state(sm_conn); 3906 break; 3907 } 3908 3909 // store public key for DH Key calculation 3910 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3911 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3912 3913 // validate public key 3914 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3915 if (err){ 3916 log_error("sm: peer public key invalid %x", err); 3917 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3918 break; 3919 } 3920 3921 // start calculating dhkey 3922 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); 3923 3924 3925 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3926 if (IS_RESPONDER(sm_conn->sm_role)){ 3927 // responder 3928 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3929 } else { 3930 // initiator 3931 // stk generation method 3932 // passkey entry: notify app to show passkey or to request passkey 3933 switch (setup->sm_stk_generation_method){ 3934 case JUST_WORKS: 3935 case NUMERIC_COMPARISON: 3936 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3937 break; 3938 case PK_RESP_INPUT: 3939 sm_sc_start_calculating_local_confirm(sm_conn); 3940 break; 3941 case PK_INIT_INPUT: 3942 case PK_BOTH_INPUT: 3943 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3944 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3945 break; 3946 } 3947 sm_sc_start_calculating_local_confirm(sm_conn); 3948 break; 3949 case OOB: 3950 // generate Nx 3951 log_info("Generate Na"); 3952 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); 3953 break; 3954 default: 3955 btstack_assert(false); 3956 break; 3957 } 3958 } 3959 break; 3960 3961 case SM_SC_W4_CONFIRMATION: 3962 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3963 sm_pdu_received_in_wrong_state(sm_conn); 3964 break; 3965 } 3966 // received confirm value 3967 reverse_128(&packet[1], setup->sm_peer_confirm); 3968 3969 #ifdef ENABLE_TESTING_SUPPORT 3970 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3971 log_info("testing_support: reset confirm value"); 3972 memset(setup->sm_peer_confirm, 0, 16); 3973 } 3974 #endif 3975 if (IS_RESPONDER(sm_conn->sm_role)){ 3976 // responder 3977 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3978 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3979 // still waiting for passkey 3980 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3981 break; 3982 } 3983 } 3984 sm_sc_start_calculating_local_confirm(sm_conn); 3985 } else { 3986 // initiator 3987 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3988 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); 3989 } else { 3990 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3991 } 3992 } 3993 break; 3994 3995 case SM_SC_W4_PAIRING_RANDOM: 3996 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3997 sm_pdu_received_in_wrong_state(sm_conn); 3998 break; 3999 } 4000 4001 // received random value 4002 reverse_128(&packet[1], setup->sm_peer_nonce); 4003 4004 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4005 // only check for JUST WORK/NC in initiator role OR passkey entry 4006 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4007 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4008 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4009 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4010 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4011 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4012 break; 4013 } 4014 4015 // OOB 4016 if (setup->sm_stk_generation_method == OOB){ 4017 4018 // setup local random, set to zero if remote did not receive our data 4019 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4020 if (IS_RESPONDER(sm_conn->sm_role)){ 4021 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4022 log_info("Reset rb as A does not have OOB data"); 4023 memset(setup->sm_rb, 0, 16); 4024 } else { 4025 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4026 log_info("Use stored rb"); 4027 log_info_hexdump(setup->sm_rb, 16); 4028 } 4029 } else { 4030 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4031 log_info("Reset ra as B does not have OOB data"); 4032 memset(setup->sm_ra, 0, 16); 4033 } else { 4034 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4035 log_info("Use stored ra"); 4036 log_info_hexdump(setup->sm_ra, 16); 4037 } 4038 } 4039 4040 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4041 if (setup->sm_have_oob_data){ 4042 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4043 break; 4044 } 4045 } 4046 4047 // TODO: we only get here for Responder role with JW/NC 4048 sm_sc_state_after_receiving_random(sm_conn); 4049 break; 4050 4051 case SM_SC_W2_CALCULATE_G2: 4052 case SM_SC_W4_CALCULATE_G2: 4053 case SM_SC_W4_CALCULATE_DHKEY: 4054 case SM_SC_W2_CALCULATE_F5_SALT: 4055 case SM_SC_W4_CALCULATE_F5_SALT: 4056 case SM_SC_W2_CALCULATE_F5_MACKEY: 4057 case SM_SC_W4_CALCULATE_F5_MACKEY: 4058 case SM_SC_W2_CALCULATE_F5_LTK: 4059 case SM_SC_W4_CALCULATE_F5_LTK: 4060 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4061 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4062 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4063 case SM_SC_W4_USER_RESPONSE: 4064 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4065 sm_pdu_received_in_wrong_state(sm_conn); 4066 break; 4067 } 4068 // store DHKey Check 4069 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4070 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4071 4072 // have we been only waiting for dhkey check command? 4073 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4074 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4075 } 4076 break; 4077 #endif 4078 4079 #ifdef ENABLE_LE_PERIPHERAL 4080 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4081 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4082 sm_pdu_received_in_wrong_state(sm_conn); 4083 break; 4084 } 4085 4086 // received confirm value 4087 reverse_128(&packet[1], setup->sm_peer_confirm); 4088 4089 #ifdef ENABLE_TESTING_SUPPORT 4090 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4091 log_info("testing_support: reset confirm value"); 4092 memset(setup->sm_peer_confirm, 0, 16); 4093 } 4094 #endif 4095 // notify client to hide shown passkey 4096 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4097 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4098 } 4099 4100 // handle user cancel pairing? 4101 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4102 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4103 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4104 break; 4105 } 4106 4107 // wait for user action? 4108 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4109 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4110 break; 4111 } 4112 4113 // calculate and send local_confirm 4114 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); 4115 break; 4116 4117 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4118 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4119 sm_pdu_received_in_wrong_state(sm_conn); 4120 break;; 4121 } 4122 4123 // received random value 4124 reverse_128(&packet[1], setup->sm_peer_random); 4125 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4126 break; 4127 #endif 4128 4129 case SM_PH3_RECEIVE_KEYS: 4130 switch(sm_pdu_code){ 4131 case SM_CODE_ENCRYPTION_INFORMATION: 4132 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4133 reverse_128(&packet[1], setup->sm_peer_ltk); 4134 break; 4135 4136 case SM_CODE_MASTER_IDENTIFICATION: 4137 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4138 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4139 reverse_64(&packet[3], setup->sm_peer_rand); 4140 break; 4141 4142 case SM_CODE_IDENTITY_INFORMATION: 4143 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4144 reverse_128(&packet[1], setup->sm_peer_irk); 4145 break; 4146 4147 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4148 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4149 setup->sm_peer_addr_type = packet[1]; 4150 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4151 break; 4152 4153 case SM_CODE_SIGNING_INFORMATION: 4154 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4155 reverse_128(&packet[1], setup->sm_peer_csrk); 4156 break; 4157 default: 4158 // Unexpected PDU 4159 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4160 break; 4161 } 4162 // done with key distribution? 4163 if (sm_key_distribution_all_received(sm_conn)){ 4164 4165 sm_key_distribution_handle_all_received(sm_conn); 4166 4167 if (IS_RESPONDER(sm_conn->sm_role)){ 4168 if (sm_ctkd_from_le(sm_conn)){ 4169 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; 4170 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4171 } else { 4172 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4173 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 4174 sm_done_for_handle(sm_conn->sm_handle); 4175 } 4176 } else { 4177 if (setup->sm_use_secure_connections){ 4178 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4179 } else { 4180 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); 4181 } 4182 } 4183 } 4184 break; 4185 default: 4186 // Unexpected PDU 4187 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4188 break; 4189 } 4190 4191 // try to send next pdu 4192 sm_trigger_run(); 4193 } 4194 4195 // Security Manager Client API 4196 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4197 sm_get_oob_data = get_oob_data_callback; 4198 } 4199 4200 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)){ 4201 sm_get_sc_oob_data = get_sc_oob_data_callback; 4202 } 4203 4204 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4205 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4206 } 4207 4208 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4209 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4210 } 4211 4212 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4213 sm_min_encryption_key_size = min_size; 4214 sm_max_encryption_key_size = max_size; 4215 } 4216 4217 void sm_set_authentication_requirements(uint8_t auth_req){ 4218 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4219 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4220 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4221 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4222 } 4223 #endif 4224 sm_auth_req = auth_req; 4225 } 4226 4227 void sm_set_io_capabilities(io_capability_t io_capability){ 4228 sm_io_capabilities = io_capability; 4229 } 4230 4231 #ifdef ENABLE_LE_PERIPHERAL 4232 void sm_set_request_security(int enable){ 4233 sm_slave_request_security = enable; 4234 } 4235 #endif 4236 4237 void sm_set_er(sm_key_t er){ 4238 (void)memcpy(sm_persistent_er, er, 16); 4239 } 4240 4241 void sm_set_ir(sm_key_t ir){ 4242 (void)memcpy(sm_persistent_ir, ir, 16); 4243 } 4244 4245 // Testing support only 4246 void sm_test_set_irk(sm_key_t irk){ 4247 (void)memcpy(sm_persistent_irk, irk, 16); 4248 dkg_state = DKG_CALC_DHK; 4249 test_use_fixed_local_irk = true; 4250 } 4251 4252 void sm_test_use_fixed_local_csrk(void){ 4253 test_use_fixed_local_csrk = true; 4254 } 4255 4256 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4257 static void sm_ec_generated(void * arg){ 4258 UNUSED(arg); 4259 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4260 // trigger pairing if pending for ec key 4261 sm_trigger_run(); 4262 } 4263 static void sm_ec_generate_new_key(void){ 4264 log_info("sm: generate new ec key"); 4265 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4266 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4267 } 4268 #endif 4269 4270 #ifdef ENABLE_TESTING_SUPPORT 4271 void sm_test_set_pairing_failure(int reason){ 4272 test_pairing_failure = reason; 4273 } 4274 #endif 4275 4276 void sm_init(void){ 4277 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4278 sm_er_ir_set_default(); 4279 4280 // defaults 4281 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4282 | SM_STK_GENERATION_METHOD_OOB 4283 | SM_STK_GENERATION_METHOD_PASSKEY 4284 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4285 4286 sm_max_encryption_key_size = 16; 4287 sm_min_encryption_key_size = 7; 4288 4289 sm_fixed_passkey_in_display_role = 0xffffffff; 4290 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4291 4292 #ifdef USE_CMAC_ENGINE 4293 sm_cmac_active = 0; 4294 #endif 4295 dkg_state = DKG_W4_WORKING; 4296 rau_state = RAU_IDLE; 4297 sm_aes128_state = SM_AES128_IDLE; 4298 sm_address_resolution_test = -1; // no private address to resolve yet 4299 sm_address_resolution_ah_calculation_active = 0; 4300 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4301 sm_address_resolution_general_queue = NULL; 4302 4303 gap_random_adress_update_period = 15 * 60 * 1000L; 4304 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4305 4306 test_use_fixed_local_csrk = false; 4307 4308 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4309 4310 // register for HCI Events from HCI 4311 hci_event_callback_registration.callback = &sm_event_packet_handler; 4312 hci_add_event_handler(&hci_event_callback_registration); 4313 4314 // 4315 btstack_crypto_init(); 4316 4317 // init le_device_db 4318 le_device_db_init(); 4319 4320 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4321 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4322 4323 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4324 sm_ec_generate_new_key(); 4325 #endif 4326 } 4327 4328 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4329 sm_fixed_passkey_in_display_role = passkey; 4330 } 4331 4332 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4333 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4334 } 4335 4336 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4337 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4338 if (!hci_con) return NULL; 4339 return &hci_con->sm_connection; 4340 } 4341 4342 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4343 switch (sm_conn->sm_engine_state){ 4344 case SM_GENERAL_IDLE: 4345 case SM_RESPONDER_IDLE: 4346 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4347 sm_trigger_run(); 4348 break; 4349 default: 4350 break; 4351 } 4352 } 4353 4354 /** 4355 * @brief Trigger Security Request 4356 */ 4357 void sm_send_security_request(hci_con_handle_t con_handle){ 4358 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4359 if (!sm_conn) return; 4360 sm_send_security_request_for_connection(sm_conn); 4361 } 4362 4363 // request pairing 4364 void sm_request_pairing(hci_con_handle_t con_handle){ 4365 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4366 if (!sm_conn) return; // wrong connection 4367 4368 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4369 if (IS_RESPONDER(sm_conn->sm_role)){ 4370 sm_send_security_request_for_connection(sm_conn); 4371 } else { 4372 // used as a trigger to start central/master/initiator security procedures 4373 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4374 uint8_t ltk[16]; 4375 bool have_ltk; 4376 switch (sm_conn->sm_irk_lookup_state){ 4377 case IRK_LOOKUP_SUCCEEDED: 4378 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4379 have_ltk = !sm_is_null_key(ltk); 4380 log_info("have ltk %u", have_ltk); 4381 if (have_ltk){ 4382 sm_conn->sm_pairing_requested = 1; 4383 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4384 sm_reencryption_started(sm_conn); 4385 break; 4386 } 4387 /* fall through */ 4388 4389 case IRK_LOOKUP_FAILED: 4390 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4391 break; 4392 default: 4393 log_info("irk lookup pending"); 4394 sm_conn->sm_pairing_requested = 1; 4395 break; 4396 } 4397 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4398 sm_conn->sm_pairing_requested = 1; 4399 } 4400 } 4401 sm_trigger_run(); 4402 } 4403 4404 // called by client app on authorization request 4405 void sm_authorization_decline(hci_con_handle_t con_handle){ 4406 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4407 if (!sm_conn) return; // wrong connection 4408 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4409 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4410 } 4411 4412 void sm_authorization_grant(hci_con_handle_t con_handle){ 4413 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4414 if (!sm_conn) return; // wrong connection 4415 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4416 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4417 } 4418 4419 // GAP Bonding API 4420 4421 void sm_bonding_decline(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_DECLINE; 4425 log_info("decline, state %u", sm_conn->sm_engine_state); 4426 switch(sm_conn->sm_engine_state){ 4427 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4428 case SM_SC_W4_USER_RESPONSE: 4429 case SM_SC_W4_CONFIRMATION: 4430 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4431 #endif 4432 case SM_PH1_W4_USER_RESPONSE: 4433 switch (setup->sm_stk_generation_method){ 4434 case PK_RESP_INPUT: 4435 case PK_INIT_INPUT: 4436 case PK_BOTH_INPUT: 4437 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4438 break; 4439 case NUMERIC_COMPARISON: 4440 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4441 break; 4442 case JUST_WORKS: 4443 case OOB: 4444 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4445 break; 4446 default: 4447 btstack_assert(false); 4448 break; 4449 } 4450 break; 4451 default: 4452 break; 4453 } 4454 sm_trigger_run(); 4455 } 4456 4457 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4458 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4459 if (!sm_conn) return; // wrong connection 4460 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4461 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4462 if (setup->sm_use_secure_connections){ 4463 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4464 } else { 4465 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); 4466 } 4467 } 4468 4469 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4470 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4471 sm_sc_prepare_dhkey_check(sm_conn); 4472 } 4473 #endif 4474 4475 sm_trigger_run(); 4476 } 4477 4478 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4479 // for now, it's the same 4480 sm_just_works_confirm(con_handle); 4481 } 4482 4483 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4484 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4485 if (!sm_conn) return; // wrong connection 4486 sm_reset_tk(); 4487 big_endian_store_32(setup->sm_tk, 12, passkey); 4488 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4489 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4490 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); 4491 } 4492 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4493 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4494 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4495 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4496 sm_sc_start_calculating_local_confirm(sm_conn); 4497 } 4498 #endif 4499 sm_trigger_run(); 4500 } 4501 4502 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4503 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4504 if (!sm_conn) return; // wrong connection 4505 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4506 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4507 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4508 switch (action){ 4509 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4510 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4511 flags |= (1u << action); 4512 break; 4513 case SM_KEYPRESS_PASSKEY_CLEARED: 4514 // clear counter, keypress & erased flags + set passkey cleared 4515 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4516 break; 4517 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4518 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4519 // erase actions queued 4520 num_actions--; 4521 if (num_actions == 0u){ 4522 // clear counter, keypress & erased flags 4523 flags &= 0x19u; 4524 } 4525 break; 4526 } 4527 num_actions++; 4528 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4529 break; 4530 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4531 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4532 // enter actions queued 4533 num_actions--; 4534 if (num_actions == 0u){ 4535 // clear counter, keypress & erased flags 4536 flags &= 0x19u; 4537 } 4538 break; 4539 } 4540 num_actions++; 4541 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4542 break; 4543 default: 4544 break; 4545 } 4546 setup->sm_keypress_notification = (num_actions << 5) | flags; 4547 sm_trigger_run(); 4548 } 4549 4550 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4551 static void sm_handle_random_result_oob(void * arg){ 4552 UNUSED(arg); 4553 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4554 sm_trigger_run(); 4555 } 4556 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4557 4558 static btstack_crypto_random_t sm_crypto_random_oob_request; 4559 4560 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4561 sm_sc_oob_callback = callback; 4562 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4563 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4564 return 0; 4565 } 4566 #endif 4567 4568 /** 4569 * @brief Get Identity Resolving state 4570 * @param con_handle 4571 * @return irk_lookup_state_t 4572 */ 4573 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4574 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4575 if (!sm_conn) return IRK_LOOKUP_IDLE; 4576 return sm_conn->sm_irk_lookup_state; 4577 } 4578 4579 /** 4580 * @brief Identify device in LE Device DB 4581 * @param handle 4582 * @returns index from le_device_db or -1 if not found/identified 4583 */ 4584 int sm_le_device_index(hci_con_handle_t con_handle ){ 4585 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4586 if (!sm_conn) return -1; 4587 return sm_conn->sm_le_db_index; 4588 } 4589 4590 static int gap_random_address_type_requires_updates(void){ 4591 switch (gap_random_adress_type){ 4592 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4593 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4594 return 0; 4595 default: 4596 return 1; 4597 } 4598 } 4599 4600 static uint8_t own_address_type(void){ 4601 switch (gap_random_adress_type){ 4602 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4603 return BD_ADDR_TYPE_LE_PUBLIC; 4604 default: 4605 return BD_ADDR_TYPE_LE_RANDOM; 4606 } 4607 } 4608 4609 // GAP LE API 4610 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4611 gap_random_address_update_stop(); 4612 gap_random_adress_type = random_address_type; 4613 hci_le_set_own_address_type(own_address_type()); 4614 if (!gap_random_address_type_requires_updates()) return; 4615 gap_random_address_update_start(); 4616 gap_random_address_trigger(); 4617 } 4618 4619 gap_random_address_type_t gap_random_address_get_mode(void){ 4620 return gap_random_adress_type; 4621 } 4622 4623 void gap_random_address_set_update_period(int period_ms){ 4624 gap_random_adress_update_period = period_ms; 4625 if (!gap_random_address_type_requires_updates()) return; 4626 gap_random_address_update_stop(); 4627 gap_random_address_update_start(); 4628 } 4629 4630 void gap_random_address_set(const bd_addr_t addr){ 4631 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4632 (void)memcpy(sm_random_address, addr, 6); 4633 rau_state = RAU_SET_ADDRESS; 4634 sm_trigger_run(); 4635 } 4636 4637 #ifdef ENABLE_LE_PERIPHERAL 4638 /* 4639 * @brief Set Advertisement Paramters 4640 * @param adv_int_min 4641 * @param adv_int_max 4642 * @param adv_type 4643 * @param direct_address_type 4644 * @param direct_address 4645 * @param channel_map 4646 * @param filter_policy 4647 * 4648 * @note own_address_type is used from gap_random_address_set_mode 4649 */ 4650 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4651 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4652 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4653 direct_address_typ, direct_address, channel_map, filter_policy); 4654 } 4655 #endif 4656 4657 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4658 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4659 // wrong connection 4660 if (!sm_conn) return 0; 4661 // already encrypted 4662 if (sm_conn->sm_connection_encrypted) return 0; 4663 // only central can re-encrypt 4664 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4665 // irk status? 4666 switch(sm_conn->sm_irk_lookup_state){ 4667 case IRK_LOOKUP_FAILED: 4668 // done, cannot setup encryption 4669 return 0; 4670 case IRK_LOOKUP_SUCCEEDED: 4671 break; 4672 default: 4673 // IR Lookup pending 4674 return 1; 4675 } 4676 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4677 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4678 } 4679 4680 void sm_set_secure_connections_only_mode(bool enable){ 4681 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4682 sm_sc_only_mode = enable; 4683 #else 4684 // SC Only mode not possible without support for SC 4685 btstack_assert(enable == false); 4686 #endif 4687 } 4688 4689 const uint8_t * gap_get_persistent_irk(void){ 4690 return sm_persistent_irk; 4691 } 4692