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 BLUEKITCHEN 24 * GMBH 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 } random_address_update_t; 111 112 typedef enum { 113 CMAC_IDLE, 114 CMAC_CALC_SUBKEYS, 115 CMAC_W4_SUBKEYS, 116 CMAC_CALC_MI, 117 CMAC_W4_MI, 118 CMAC_CALC_MLAST, 119 CMAC_W4_MLAST 120 } cmac_state_t; 121 122 typedef enum { 123 JUST_WORKS, 124 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 125 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 126 PK_BOTH_INPUT, // Only input on both, both input PK 127 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 128 OOB // OOB available on one (SC) or both sides (legacy) 129 } stk_generation_method_t; 130 131 typedef enum { 132 SM_USER_RESPONSE_IDLE, 133 SM_USER_RESPONSE_PENDING, 134 SM_USER_RESPONSE_CONFIRM, 135 SM_USER_RESPONSE_PASSKEY, 136 SM_USER_RESPONSE_DECLINE 137 } sm_user_response_t; 138 139 typedef enum { 140 SM_AES128_IDLE, 141 SM_AES128_ACTIVE 142 } sm_aes128_state_t; 143 144 typedef enum { 145 ADDRESS_RESOLUTION_IDLE, 146 ADDRESS_RESOLUTION_GENERAL, 147 ADDRESS_RESOLUTION_FOR_CONNECTION, 148 } address_resolution_mode_t; 149 150 typedef enum { 151 ADDRESS_RESOLUTION_SUCCEEDED, 152 ADDRESS_RESOLUTION_FAILED, 153 } address_resolution_event_t; 154 155 typedef enum { 156 EC_KEY_GENERATION_IDLE, 157 EC_KEY_GENERATION_ACTIVE, 158 EC_KEY_GENERATION_DONE, 159 } ec_key_generation_state_t; 160 161 typedef enum { 162 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 163 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 165 } sm_state_var_t; 166 167 typedef enum { 168 SM_SC_OOB_IDLE, 169 SM_SC_OOB_W4_RANDOM, 170 SM_SC_OOB_W2_CALC_CONFIRM, 171 SM_SC_OOB_W4_CONFIRM, 172 } sm_sc_oob_state_t; 173 174 typedef uint8_t sm_key24_t[3]; 175 typedef uint8_t sm_key56_t[7]; 176 typedef uint8_t sm_key256_t[32]; 177 178 // 179 // GLOBAL DATA 180 // 181 182 static bool sm_initialized; 183 184 static bool test_use_fixed_local_csrk; 185 static bool test_use_fixed_local_irk; 186 187 #ifdef ENABLE_TESTING_SUPPORT 188 static uint8_t test_pairing_failure; 189 #endif 190 191 // configuration 192 static uint8_t sm_accepted_stk_generation_methods; 193 static uint8_t sm_max_encryption_key_size; 194 static uint8_t sm_min_encryption_key_size; 195 static uint8_t sm_auth_req = 0; 196 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 197 static uint8_t sm_slave_request_security; 198 static uint32_t sm_fixed_passkey_in_display_role; 199 static bool sm_reconstruct_ltk_without_le_device_db_entry; 200 201 #ifdef ENABLE_LE_SECURE_CONNECTIONS 202 static bool sm_sc_only_mode; 203 static uint8_t sm_sc_oob_random[16]; 204 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 205 static sm_sc_oob_state_t sm_sc_oob_state; 206 #endif 207 208 209 static bool sm_persistent_keys_random_active; 210 static const btstack_tlv_t * sm_tlv_impl; 211 static void * sm_tlv_context; 212 213 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 214 static sm_key_t sm_persistent_er; 215 static sm_key_t sm_persistent_ir; 216 217 // derived from sm_persistent_ir 218 static sm_key_t sm_persistent_dhk; 219 static sm_key_t sm_persistent_irk; 220 static derived_key_generation_t dkg_state; 221 222 // derived from sm_persistent_er 223 // .. 224 225 // random address update 226 static random_address_update_t rau_state; 227 static bd_addr_t sm_random_address; 228 229 #ifdef USE_CMAC_ENGINE 230 // CMAC Calculation: General 231 static btstack_crypto_aes128_cmac_t sm_cmac_request; 232 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 233 static uint8_t sm_cmac_active; 234 static uint8_t sm_cmac_hash[16]; 235 #endif 236 237 // CMAC for ATT Signed Writes 238 #ifdef ENABLE_LE_SIGNED_WRITE 239 static uint16_t sm_cmac_signed_write_message_len; 240 static uint8_t sm_cmac_signed_write_header[3]; 241 static const uint8_t * sm_cmac_signed_write_message; 242 static uint8_t sm_cmac_signed_write_sign_counter[4]; 243 #endif 244 245 // CMAC for Secure Connection functions 246 #ifdef ENABLE_LE_SECURE_CONNECTIONS 247 static sm_connection_t * sm_cmac_connection; 248 static uint8_t sm_cmac_sc_buffer[80]; 249 #endif 250 251 // resolvable private address lookup / CSRK calculation 252 static int sm_address_resolution_test; 253 static int sm_address_resolution_ah_calculation_active; 254 static uint8_t sm_address_resolution_addr_type; 255 static bd_addr_t sm_address_resolution_address; 256 static void * sm_address_resolution_context; 257 static address_resolution_mode_t sm_address_resolution_mode; 258 static btstack_linked_list_t sm_address_resolution_general_queue; 259 260 // aes128 crypto engine. 261 static sm_aes128_state_t sm_aes128_state; 262 263 // crypto 264 static btstack_crypto_random_t sm_crypto_random_request; 265 static btstack_crypto_aes128_t sm_crypto_aes128_request; 266 #ifdef ENABLE_LE_SECURE_CONNECTIONS 267 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 268 #endif 269 270 // temp storage for random data 271 static uint8_t sm_random_data[8]; 272 static uint8_t sm_aes128_key[16]; 273 static uint8_t sm_aes128_plaintext[16]; 274 static uint8_t sm_aes128_ciphertext[16]; 275 276 // to receive hci events 277 static btstack_packet_callback_registration_t hci_event_callback_registration; 278 279 /* to dispatch sm event */ 280 static btstack_linked_list_t sm_event_handlers; 281 282 /* to schedule calls to sm_run */ 283 static btstack_timer_source_t sm_run_timer; 284 285 // LE Secure Connections 286 #ifdef ENABLE_LE_SECURE_CONNECTIONS 287 static ec_key_generation_state_t ec_key_generation_state; 288 static uint8_t ec_q[64]; 289 #endif 290 291 // 292 // Volume 3, Part H, Chapter 24 293 // "Security shall be initiated by the Security Manager in the device in the master role. 294 // The device in the slave role shall be the responding device." 295 // -> master := initiator, slave := responder 296 // 297 298 // data needed for security setup 299 typedef struct sm_setup_context { 300 301 btstack_timer_source_t sm_timeout; 302 303 // user response, (Phase 1 and/or 2) 304 uint8_t sm_user_response; 305 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 306 307 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 308 uint8_t sm_key_distribution_send_set; 309 uint8_t sm_key_distribution_sent_set; 310 uint8_t sm_key_distribution_expected_set; 311 uint8_t sm_key_distribution_received_set; 312 313 // Phase 2 (Pairing over SMP) 314 stk_generation_method_t sm_stk_generation_method; 315 sm_key_t sm_tk; 316 uint8_t sm_have_oob_data; 317 uint8_t sm_use_secure_connections; 318 319 sm_key_t sm_c1_t3_value; // c1 calculation 320 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 321 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 322 sm_key_t sm_local_random; 323 sm_key_t sm_local_confirm; 324 sm_key_t sm_peer_random; 325 sm_key_t sm_peer_confirm; 326 uint8_t sm_m_addr_type; // address and type can be removed 327 uint8_t sm_s_addr_type; // '' 328 bd_addr_t sm_m_address; // '' 329 bd_addr_t sm_s_address; // '' 330 sm_key_t sm_ltk; 331 332 uint8_t sm_state_vars; 333 #ifdef ENABLE_LE_SECURE_CONNECTIONS 334 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 335 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 336 sm_key_t sm_local_nonce; // might be combined with sm_local_random 337 uint8_t sm_dhkey[32]; 338 sm_key_t sm_peer_dhkey_check; 339 sm_key_t sm_local_dhkey_check; 340 sm_key_t sm_ra; 341 sm_key_t sm_rb; 342 sm_key_t sm_t; // used for f5 and h6 343 sm_key_t sm_mackey; 344 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 345 #endif 346 347 // Phase 3 348 349 // key distribution, we generate 350 uint16_t sm_local_y; 351 uint16_t sm_local_div; 352 uint16_t sm_local_ediv; 353 uint8_t sm_local_rand[8]; 354 sm_key_t sm_local_ltk; 355 sm_key_t sm_local_csrk; 356 sm_key_t sm_local_irk; 357 // sm_local_address/addr_type not needed 358 359 // key distribution, received from peer 360 uint16_t sm_peer_y; 361 uint16_t sm_peer_div; 362 uint16_t sm_peer_ediv; 363 uint8_t sm_peer_rand[8]; 364 sm_key_t sm_peer_ltk; 365 sm_key_t sm_peer_irk; 366 sm_key_t sm_peer_csrk; 367 uint8_t sm_peer_addr_type; 368 bd_addr_t sm_peer_address; 369 #ifdef ENABLE_LE_SIGNED_WRITE 370 int sm_le_device_index; 371 #endif 372 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 373 link_key_t sm_link_key; 374 link_key_type_t sm_link_key_type; 375 #endif 376 } sm_setup_context_t; 377 378 // 379 static sm_setup_context_t the_setup; 380 static sm_setup_context_t * setup = &the_setup; 381 382 // active connection - the one for which the_setup is used for 383 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 384 385 // @return 1 if oob data is available 386 // stores oob data in provided 16 byte buffer if not null 387 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 388 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); 389 390 static void sm_run(void); 391 static void sm_done_for_handle(hci_con_handle_t con_handle); 392 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 393 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 394 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 395 #endif 396 static inline int sm_calc_actual_encryption_key_size(int other); 397 static int sm_validate_stk_generation_method(void); 398 static void sm_handle_encryption_result_address_resolution(void *arg); 399 static void sm_handle_encryption_result_dkg_dhk(void *arg); 400 static void sm_handle_encryption_result_dkg_irk(void *arg); 401 static void sm_handle_encryption_result_enc_a(void *arg); 402 static void sm_handle_encryption_result_enc_b(void *arg); 403 static void sm_handle_encryption_result_enc_c(void *arg); 404 static void sm_handle_encryption_result_enc_csrk(void *arg); 405 static void sm_handle_encryption_result_enc_d(void * arg); 406 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 407 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 408 #ifdef ENABLE_LE_PERIPHERAL 409 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 410 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 411 #endif 412 static void sm_handle_encryption_result_enc_stk(void *arg); 413 static void sm_handle_encryption_result_rau(void *arg); 414 static void sm_handle_random_result_ph2_tk(void * arg); 415 static void sm_handle_random_result_rau(void * arg); 416 #ifdef ENABLE_LE_SECURE_CONNECTIONS 417 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)); 418 static void sm_ec_generate_new_key(void); 419 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 420 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 421 static int sm_passkey_entry(stk_generation_method_t method); 422 #endif 423 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 424 425 static void log_info_hex16(const char * name, uint16_t value){ 426 log_info("%-6s 0x%04x", name, value); 427 } 428 429 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 430 // return packet[0]; 431 // } 432 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 433 return packet[1]; 434 } 435 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 436 return packet[2]; 437 } 438 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 439 return packet[3]; 440 } 441 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 442 return packet[4]; 443 } 444 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 445 return packet[5]; 446 } 447 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 448 return packet[6]; 449 } 450 451 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 452 packet[0] = code; 453 } 454 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 455 packet[1] = io_capability; 456 } 457 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 458 packet[2] = oob_data_flag; 459 } 460 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 461 packet[3] = auth_req; 462 } 463 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 464 packet[4] = max_encryption_key_size; 465 } 466 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 467 packet[5] = initiator_key_distribution; 468 } 469 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 470 packet[6] = responder_key_distribution; 471 } 472 473 // @return 1 if all bytes are 0 474 static bool sm_is_null(uint8_t * data, int size){ 475 int i; 476 for (i=0; i < size ; i++){ 477 if (data[i] != 0) { 478 return false; 479 } 480 } 481 return true; 482 } 483 484 static bool sm_is_null_random(uint8_t random[8]){ 485 return sm_is_null(random, 8); 486 } 487 488 static bool sm_is_null_key(uint8_t * key){ 489 return sm_is_null(key, 16); 490 } 491 492 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 493 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 494 UNUSED(ts); 495 sm_run(); 496 } 497 static void sm_trigger_run(void){ 498 if (!sm_initialized) return; 499 (void)btstack_run_loop_remove_timer(&sm_run_timer); 500 btstack_run_loop_set_timer(&sm_run_timer, 0); 501 btstack_run_loop_add_timer(&sm_run_timer); 502 } 503 504 // Key utils 505 static void sm_reset_tk(void){ 506 int i; 507 for (i=0;i<16;i++){ 508 setup->sm_tk[i] = 0; 509 } 510 } 511 512 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 513 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 514 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 515 int i; 516 for (i = max_encryption_size ; i < 16 ; i++){ 517 key[15-i] = 0; 518 } 519 } 520 521 // ER / IR checks 522 static void sm_er_ir_set_default(void){ 523 int i; 524 for (i=0;i<16;i++){ 525 sm_persistent_er[i] = 0x30 + i; 526 sm_persistent_ir[i] = 0x90 + i; 527 } 528 } 529 530 static int sm_er_is_default(void){ 531 int i; 532 for (i=0;i<16;i++){ 533 if (sm_persistent_er[i] != (0x30+i)) return 0; 534 } 535 return 1; 536 } 537 538 static int sm_ir_is_default(void){ 539 int i; 540 for (i=0;i<16;i++){ 541 if (sm_persistent_ir[i] != (0x90+i)) return 0; 542 } 543 return 1; 544 } 545 546 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 547 UNUSED(channel); 548 549 // log event 550 hci_dump_packet(packet_type, 1, packet, size); 551 // dispatch to all event handlers 552 btstack_linked_list_iterator_t it; 553 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 554 while (btstack_linked_list_iterator_has_next(&it)){ 555 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 556 entry->callback(packet_type, 0, packet, size); 557 } 558 } 559 560 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){ 561 event[0] = type; 562 event[1] = event_size - 2; 563 little_endian_store_16(event, 2, con_handle); 564 event[4] = addr_type; 565 reverse_bd_addr(address, &event[5]); 566 } 567 568 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 569 uint8_t event[11]; 570 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 571 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 572 } 573 574 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){ 575 uint8_t event[15]; 576 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 577 little_endian_store_32(event, 11, passkey); 578 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 579 } 580 581 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){ 582 // fetch addr and addr type from db, only called for valid entries 583 bd_addr_t identity_address; 584 int identity_address_type; 585 le_device_db_info(index, &identity_address_type, identity_address, NULL); 586 587 uint8_t event[20]; 588 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 589 event[11] = identity_address_type; 590 reverse_bd_addr(identity_address, &event[12]); 591 little_endian_store_16(event, 18, index); 592 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 593 } 594 595 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){ 596 uint8_t event[12]; 597 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 598 event[11] = status; 599 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 600 } 601 602 603 static void sm_reencryption_started(sm_connection_t * sm_conn){ 604 605 if (sm_conn->sm_reencryption_active) return; 606 607 sm_conn->sm_reencryption_active = true; 608 609 int identity_addr_type; 610 bd_addr_t identity_addr; 611 if (sm_conn->sm_le_db_index >= 0){ 612 // fetch addr and addr type from db, only called for valid entries 613 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 614 } else { 615 // for legacy pairing with LTK re-construction, use current peer addr 616 identity_addr_type = sm_conn->sm_peer_addr_type; 617 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 618 } 619 620 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 621 } 622 623 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 624 625 if (!sm_conn->sm_reencryption_active) return; 626 627 sm_conn->sm_reencryption_active = false; 628 629 int identity_addr_type; 630 bd_addr_t identity_addr; 631 if (sm_conn->sm_le_db_index >= 0){ 632 // fetch addr and addr type from db, only called for valid entries 633 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 634 } else { 635 // for legacy pairing with LTK re-construction, use current peer addr 636 identity_addr_type = sm_conn->sm_peer_addr_type; 637 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 638 } 639 640 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 641 } 642 643 static void sm_pairing_started(sm_connection_t * sm_conn){ 644 645 if (sm_conn->sm_pairing_active) return; 646 647 sm_conn->sm_pairing_active = true; 648 649 uint8_t event[11]; 650 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 651 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 652 } 653 654 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 655 656 if (!sm_conn->sm_pairing_active) return; 657 658 sm_conn->sm_pairing_active = false; 659 660 uint8_t event[13]; 661 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 662 event[11] = status; 663 event[12] = reason; 664 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 665 } 666 667 // SMP Timeout implementation 668 669 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 670 // the Security Manager Timer shall be reset and started. 671 // 672 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 673 // 674 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 675 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 676 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 677 // established. 678 679 static void sm_timeout_handler(btstack_timer_source_t * timer){ 680 log_info("SM timeout"); 681 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 682 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 683 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 684 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 685 sm_done_for_handle(sm_conn->sm_handle); 686 687 // trigger handling of next ready connection 688 sm_run(); 689 } 690 static void sm_timeout_start(sm_connection_t * sm_conn){ 691 btstack_run_loop_remove_timer(&setup->sm_timeout); 692 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 693 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 694 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 695 btstack_run_loop_add_timer(&setup->sm_timeout); 696 } 697 static void sm_timeout_stop(void){ 698 btstack_run_loop_remove_timer(&setup->sm_timeout); 699 } 700 static void sm_timeout_reset(sm_connection_t * sm_conn){ 701 sm_timeout_stop(); 702 sm_timeout_start(sm_conn); 703 } 704 705 // end of sm timeout 706 707 // GAP Random Address updates 708 static gap_random_address_type_t gap_random_adress_type; 709 static btstack_timer_source_t gap_random_address_update_timer; 710 static uint32_t gap_random_adress_update_period; 711 712 static void gap_random_address_trigger(void){ 713 log_info("gap_random_address_trigger, state %u", rau_state); 714 if (rau_state != RAU_IDLE) return; 715 rau_state = RAU_GET_RANDOM; 716 sm_trigger_run(); 717 } 718 719 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 720 UNUSED(timer); 721 722 log_info("GAP Random Address Update due"); 723 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 724 btstack_run_loop_add_timer(&gap_random_address_update_timer); 725 gap_random_address_trigger(); 726 } 727 728 static void gap_random_address_update_start(void){ 729 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 730 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 731 btstack_run_loop_add_timer(&gap_random_address_update_timer); 732 } 733 734 static void gap_random_address_update_stop(void){ 735 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 736 } 737 738 // ah(k,r) helper 739 // r = padding || r 740 // r - 24 bit value 741 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 742 // r'= padding || r 743 memset(r_prime, 0, 16); 744 (void)memcpy(&r_prime[13], r, 3); 745 } 746 747 // d1 helper 748 // d' = padding || r || d 749 // d,r - 16 bit values 750 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 751 // d'= padding || r || d 752 memset(d1_prime, 0, 16); 753 big_endian_store_16(d1_prime, 12, r); 754 big_endian_store_16(d1_prime, 14, d); 755 } 756 757 // calculate arguments for first AES128 operation in C1 function 758 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){ 759 760 // p1 = pres || preq || rat’ || iat’ 761 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 762 // cant octet of pres becomes the most significant octet of p1. 763 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 764 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 765 // p1 is 0x05000800000302070710000001010001." 766 767 sm_key_t p1; 768 reverse_56(pres, &p1[0]); 769 reverse_56(preq, &p1[7]); 770 p1[14] = rat; 771 p1[15] = iat; 772 log_info_key("p1", p1); 773 log_info_key("r", r); 774 775 // t1 = r xor p1 776 int i; 777 for (i=0;i<16;i++){ 778 t1[i] = r[i] ^ p1[i]; 779 } 780 log_info_key("t1", t1); 781 } 782 783 // calculate arguments for second AES128 operation in C1 function 784 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 785 // p2 = padding || ia || ra 786 // "The least significant octet of ra becomes the least significant octet of p2 and 787 // the most significant octet of padding becomes the most significant octet of p2. 788 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 789 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 790 791 sm_key_t p2; 792 memset(p2, 0, 16); 793 (void)memcpy(&p2[4], ia, 6); 794 (void)memcpy(&p2[10], ra, 6); 795 log_info_key("p2", p2); 796 797 // c1 = e(k, t2_xor_p2) 798 int i; 799 for (i=0;i<16;i++){ 800 t3[i] = t2[i] ^ p2[i]; 801 } 802 log_info_key("t3", t3); 803 } 804 805 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 806 log_info_key("r1", r1); 807 log_info_key("r2", r2); 808 (void)memcpy(&r_prime[8], &r2[8], 8); 809 (void)memcpy(&r_prime[0], &r1[8], 8); 810 } 811 812 813 // decide on stk generation based on 814 // - pairing request 815 // - io capabilities 816 // - OOB data availability 817 static void sm_setup_tk(void){ 818 819 // horizontal: initiator capabilities 820 // vertial: responder capabilities 821 static const stk_generation_method_t stk_generation_method [5] [5] = { 822 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 823 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 824 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 825 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 826 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 827 }; 828 829 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 830 #ifdef ENABLE_LE_SECURE_CONNECTIONS 831 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 832 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 833 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 834 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 835 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 836 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 837 }; 838 #endif 839 840 // default: just works 841 setup->sm_stk_generation_method = JUST_WORKS; 842 843 #ifdef ENABLE_LE_SECURE_CONNECTIONS 844 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 845 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 846 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 847 #else 848 setup->sm_use_secure_connections = 0; 849 #endif 850 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 851 852 853 // decide if OOB will be used based on SC vs. Legacy and oob flags 854 bool use_oob; 855 if (setup->sm_use_secure_connections){ 856 // In LE Secure Connections pairing, the out of band method is used if at least 857 // one device has the peer device's out of band authentication data available. 858 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 859 } else { 860 // In LE legacy pairing, the out of band method is used if both the devices have 861 // the other device's out of band authentication data available. 862 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 863 } 864 if (use_oob){ 865 log_info("SM: have OOB data"); 866 log_info_key("OOB", setup->sm_tk); 867 setup->sm_stk_generation_method = OOB; 868 return; 869 } 870 871 // If both devices have not set the MITM option in the Authentication Requirements 872 // Flags, then the IO capabilities shall be ignored and the Just Works association 873 // model shall be used. 874 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 875 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 876 log_info("SM: MITM not required by both -> JUST WORKS"); 877 return; 878 } 879 880 // Reset TK as it has been setup in sm_init_setup 881 sm_reset_tk(); 882 883 // Also use just works if unknown io capabilites 884 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)){ 885 return; 886 } 887 888 // Otherwise the IO capabilities of the devices shall be used to determine the 889 // pairing method as defined in Table 2.4. 890 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 891 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 892 893 #ifdef ENABLE_LE_SECURE_CONNECTIONS 894 // table not define by default 895 if (setup->sm_use_secure_connections){ 896 generation_method = stk_generation_method_with_secure_connection; 897 } 898 #endif 899 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)]; 900 901 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 902 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); 903 } 904 905 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 906 int flags = 0; 907 if (key_set & SM_KEYDIST_ENC_KEY){ 908 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 909 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 910 } 911 if (key_set & SM_KEYDIST_ID_KEY){ 912 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 913 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 914 } 915 if (key_set & SM_KEYDIST_SIGN){ 916 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 917 } 918 return flags; 919 } 920 921 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 922 setup->sm_key_distribution_received_set = 0; 923 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 924 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 925 setup->sm_key_distribution_sent_set = 0; 926 #ifdef ENABLE_LE_SIGNED_WRITE 927 setup->sm_le_device_index = -1; 928 #endif 929 } 930 931 // CSRK Key Lookup 932 933 934 static int sm_address_resolution_idle(void){ 935 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 936 } 937 938 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){ 939 (void)memcpy(sm_address_resolution_address, addr, 6); 940 sm_address_resolution_addr_type = addr_type; 941 sm_address_resolution_test = 0; 942 sm_address_resolution_mode = mode; 943 sm_address_resolution_context = context; 944 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 945 } 946 947 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 948 // check if already in list 949 btstack_linked_list_iterator_t it; 950 sm_lookup_entry_t * entry; 951 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 952 while(btstack_linked_list_iterator_has_next(&it)){ 953 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 954 if (entry->address_type != address_type) continue; 955 if (memcmp(entry->address, address, 6)) continue; 956 // already in list 957 return BTSTACK_BUSY; 958 } 959 entry = btstack_memory_sm_lookup_entry_get(); 960 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 961 entry->address_type = (bd_addr_type_t) address_type; 962 (void)memcpy(entry->address, address, 6); 963 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 964 sm_trigger_run(); 965 return 0; 966 } 967 968 // CMAC calculation using AES Engineq 969 #ifdef USE_CMAC_ENGINE 970 971 static void sm_cmac_done_trampoline(void * arg){ 972 UNUSED(arg); 973 sm_cmac_active = 0; 974 (*sm_cmac_done_callback)(sm_cmac_hash); 975 sm_trigger_run(); 976 } 977 978 int sm_cmac_ready(void){ 979 return sm_cmac_active == 0u; 980 } 981 #endif 982 983 #ifdef ENABLE_LE_SECURE_CONNECTIONS 984 // generic cmac calculation 985 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)){ 986 sm_cmac_active = 1; 987 sm_cmac_done_callback = done_callback; 988 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 989 } 990 #endif 991 992 // cmac for ATT Message signing 993 #ifdef ENABLE_LE_SIGNED_WRITE 994 995 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)){ 996 sm_cmac_active = 1; 997 sm_cmac_done_callback = done_callback; 998 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 999 } 1000 1001 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1002 if (offset >= sm_cmac_signed_write_message_len) { 1003 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1004 return 0; 1005 } 1006 1007 offset = sm_cmac_signed_write_message_len - 1 - offset; 1008 1009 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1010 if (offset < 3){ 1011 return sm_cmac_signed_write_header[offset]; 1012 } 1013 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1014 if (offset < actual_message_len_incl_header){ 1015 return sm_cmac_signed_write_message[offset - 3]; 1016 } 1017 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1018 } 1019 1020 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)){ 1021 // ATT Message Signing 1022 sm_cmac_signed_write_header[0] = opcode; 1023 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1024 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1025 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1026 sm_cmac_signed_write_message = message; 1027 sm_cmac_signed_write_message_len = total_message_len; 1028 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1029 } 1030 #endif 1031 1032 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1033 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1034 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1035 sm_conn->sm_pairing_active = true; 1036 switch (setup->sm_stk_generation_method){ 1037 case PK_RESP_INPUT: 1038 if (IS_RESPONDER(sm_conn->sm_role)){ 1039 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1040 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1041 } else { 1042 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)); 1043 } 1044 break; 1045 case PK_INIT_INPUT: 1046 if (IS_RESPONDER(sm_conn->sm_role)){ 1047 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)); 1048 } else { 1049 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1050 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1051 } 1052 break; 1053 case PK_BOTH_INPUT: 1054 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1055 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1056 break; 1057 case NUMERIC_COMPARISON: 1058 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1059 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)); 1060 break; 1061 case JUST_WORKS: 1062 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1063 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1064 break; 1065 case OOB: 1066 // client already provided OOB data, let's skip notification. 1067 break; 1068 default: 1069 btstack_assert(false); 1070 break; 1071 } 1072 } 1073 1074 static bool sm_key_distribution_all_received(void) { 1075 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, bution_expected_set); 1076 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1077 } 1078 1079 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1080 if (sm_active_connection_handle == con_handle){ 1081 sm_timeout_stop(); 1082 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1083 log_info("sm: connection 0x%x released setup context", con_handle); 1084 1085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1086 // generate new ec key after each pairing (that used it) 1087 if (setup->sm_use_secure_connections){ 1088 sm_ec_generate_new_key(); 1089 } 1090 #endif 1091 } 1092 } 1093 1094 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1095 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1096 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1097 sm_done_for_handle(connection->sm_handle); 1098 } 1099 1100 static int sm_key_distribution_flags_for_auth_req(void){ 1101 1102 int flags = SM_KEYDIST_ID_KEY; 1103 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1104 // encryption and signing information only if bonding requested 1105 flags |= SM_KEYDIST_ENC_KEY; 1106 #ifdef ENABLE_LE_SIGNED_WRITE 1107 flags |= SM_KEYDIST_SIGN; 1108 #endif 1109 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1110 // LinkKey for CTKD requires SC 1111 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1112 flags |= SM_KEYDIST_LINK_KEY; 1113 } 1114 #endif 1115 } 1116 return flags; 1117 } 1118 1119 static void sm_reset_setup(void){ 1120 // fill in sm setup 1121 setup->sm_state_vars = 0; 1122 setup->sm_keypress_notification = 0; 1123 setup->sm_have_oob_data = 0; 1124 sm_reset_tk(); 1125 } 1126 1127 static void sm_init_setup(sm_connection_t * sm_conn){ 1128 // fill in sm setup 1129 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1130 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1131 1132 // query client for Legacy Pairing OOB data 1133 if (sm_get_oob_data != NULL) { 1134 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1135 } 1136 1137 // if available and SC supported, also ask for SC OOB Data 1138 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1139 memset(setup->sm_ra, 0, 16); 1140 memset(setup->sm_rb, 0, 16); 1141 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1142 if (sm_get_sc_oob_data != NULL){ 1143 if (IS_RESPONDER(sm_conn->sm_role)){ 1144 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1145 sm_conn->sm_peer_addr_type, 1146 sm_conn->sm_peer_address, 1147 setup->sm_peer_confirm, 1148 setup->sm_ra); 1149 } else { 1150 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1151 sm_conn->sm_peer_addr_type, 1152 sm_conn->sm_peer_address, 1153 setup->sm_peer_confirm, 1154 setup->sm_rb); 1155 } 1156 } else { 1157 setup->sm_have_oob_data = 0; 1158 } 1159 } 1160 #endif 1161 1162 sm_pairing_packet_t * local_packet; 1163 if (IS_RESPONDER(sm_conn->sm_role)){ 1164 // slave 1165 local_packet = &setup->sm_s_pres; 1166 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1167 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1168 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1169 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1170 } else { 1171 // master 1172 local_packet = &setup->sm_m_preq; 1173 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1174 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1175 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1176 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1177 1178 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1179 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1180 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1181 } 1182 1183 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1184 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1185 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1186 // enable SC for SC only mode 1187 if (sm_sc_only_mode){ 1188 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1189 max_encryption_key_size = 16; 1190 } 1191 #endif 1192 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1193 // set CT2 if SC + Bonding + CTKD 1194 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1195 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1196 auth_req |= SM_AUTHREQ_CT2; 1197 } 1198 #endif 1199 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1200 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1201 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1202 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1203 } 1204 1205 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1206 1207 sm_pairing_packet_t * remote_packet; 1208 uint8_t keys_to_send; 1209 uint8_t keys_to_receive; 1210 if (IS_RESPONDER(sm_conn->sm_role)){ 1211 // slave / responder 1212 remote_packet = &setup->sm_m_preq; 1213 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1214 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1215 } else { 1216 // master / initiator 1217 remote_packet = &setup->sm_s_pres; 1218 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1219 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1220 } 1221 1222 // check key size 1223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1224 // SC Only mandates 128 bit key size 1225 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1226 return SM_REASON_ENCRYPTION_KEY_SIZE; 1227 } 1228 #endif 1229 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1230 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1231 1232 // decide on STK generation method / SC 1233 sm_setup_tk(); 1234 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1235 1236 // check if STK generation method is acceptable by client 1237 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1238 1239 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1240 // Check LE SC Only mode 1241 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1242 log_info("SC Only mode active but SC not possible"); 1243 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1244 } 1245 1246 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1247 if (setup->sm_use_secure_connections){ 1248 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1249 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1250 } 1251 #endif 1252 1253 // identical to responder 1254 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1255 1256 // JUST WORKS doens't provide authentication 1257 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1258 1259 return 0; 1260 } 1261 1262 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1263 1264 // cache and reset context 1265 int matched_device_id = sm_address_resolution_test; 1266 address_resolution_mode_t mode = sm_address_resolution_mode; 1267 void * context = sm_address_resolution_context; 1268 1269 // reset context 1270 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1271 sm_address_resolution_context = NULL; 1272 sm_address_resolution_test = -1; 1273 hci_con_handle_t con_handle = 0; 1274 1275 sm_connection_t * sm_connection; 1276 sm_key_t ltk; 1277 bool have_ltk; 1278 #ifdef ENABLE_LE_CENTRAL 1279 bool trigger_pairing; 1280 #endif 1281 switch (mode){ 1282 case ADDRESS_RESOLUTION_GENERAL: 1283 break; 1284 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1285 sm_connection = (sm_connection_t *) context; 1286 con_handle = sm_connection->sm_handle; 1287 1288 // have ltk -> start encryption / send security request 1289 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1290 // "When a bond has been created between two devices, any reconnection should result in the local device 1291 // enabling or requesting encryption with the remote device before initiating any service request." 1292 1293 switch (event){ 1294 case ADDRESS_RESOLUTION_SUCCEEDED: 1295 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1296 sm_connection->sm_le_db_index = matched_device_id; 1297 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1298 1299 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1300 have_ltk = !sm_is_null_key(ltk); 1301 1302 if (sm_connection->sm_role) { 1303 #ifdef ENABLE_LE_PERIPHERAL 1304 // IRK required before, continue 1305 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1306 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1307 break; 1308 } 1309 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1310 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1311 break; 1312 } 1313 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1314 sm_connection->sm_pairing_requested = 0; 1315 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1316 // trigger security request for Proactive Authentication if LTK available 1317 trigger_security_request = trigger_security_request || have_ltk; 1318 #endif 1319 1320 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1321 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1322 1323 if (trigger_security_request){ 1324 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1325 if (have_ltk){ 1326 sm_reencryption_started(sm_connection); 1327 } else { 1328 sm_pairing_started(sm_connection); 1329 } 1330 sm_trigger_run(); 1331 } 1332 #endif 1333 } else { 1334 1335 #ifdef ENABLE_LE_CENTRAL 1336 // check if pairing already requested and reset requests 1337 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1338 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1339 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1340 sm_connection->sm_security_request_received = 0; 1341 sm_connection->sm_pairing_requested = 0; 1342 bool trigger_reencryption = false; 1343 1344 if (have_ltk){ 1345 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1346 trigger_reencryption = true; 1347 #else 1348 if (trigger_pairing){ 1349 trigger_reencryption = true; 1350 } else { 1351 log_info("central: defer enabling encryption for bonded device"); 1352 } 1353 #endif 1354 } 1355 1356 if (trigger_reencryption){ 1357 log_info("central: enable encryption for bonded device"); 1358 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1359 break; 1360 } 1361 1362 // pairing_request -> send pairing request 1363 if (trigger_pairing){ 1364 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1365 break; 1366 } 1367 #endif 1368 } 1369 break; 1370 case ADDRESS_RESOLUTION_FAILED: 1371 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1372 if (sm_connection->sm_role) { 1373 #ifdef ENABLE_LE_PERIPHERAL 1374 // LTK request received before, IRK required -> negative LTK reply 1375 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1376 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1377 } 1378 // send security request if requested 1379 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1380 sm_connection->sm_pairing_requested = 0; 1381 if (trigger_security_request){ 1382 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1383 sm_pairing_started(sm_connection); 1384 } 1385 break; 1386 #endif 1387 } 1388 #ifdef ENABLE_LE_CENTRAL 1389 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1390 sm_connection->sm_security_request_received = 0; 1391 sm_connection->sm_pairing_requested = 0; 1392 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1393 #endif 1394 break; 1395 1396 default: 1397 btstack_assert(false); 1398 break; 1399 } 1400 break; 1401 default: 1402 break; 1403 } 1404 1405 switch (event){ 1406 case ADDRESS_RESOLUTION_SUCCEEDED: 1407 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1408 break; 1409 case ADDRESS_RESOLUTION_FAILED: 1410 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1411 break; 1412 default: 1413 btstack_assert(false); 1414 break; 1415 } 1416 } 1417 1418 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1419 int le_db_index = -1; 1420 1421 // lookup device based on IRK 1422 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1423 int i; 1424 for (i=0; i < le_device_db_max_count(); i++){ 1425 sm_key_t irk; 1426 bd_addr_t address; 1427 int address_type = BD_ADDR_TYPE_UNKNOWN; 1428 le_device_db_info(i, &address_type, address, irk); 1429 // skip unused entries 1430 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1431 // compare Identity Address 1432 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1433 // compare Identity Resolving Key 1434 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1435 1436 log_info("sm: device found for IRK, updating"); 1437 le_db_index = i; 1438 break; 1439 } 1440 } else { 1441 // assert IRK is set to zero 1442 memset(setup->sm_peer_irk, 0, 16); 1443 } 1444 1445 // if not found, lookup via public address if possible 1446 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1447 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1448 int i; 1449 for (i=0; i < le_device_db_max_count(); i++){ 1450 bd_addr_t address; 1451 int address_type = BD_ADDR_TYPE_UNKNOWN; 1452 le_device_db_info(i, &address_type, address, NULL); 1453 // skip unused entries 1454 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1455 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1456 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1457 log_info("sm: device found for public address, updating"); 1458 le_db_index = i; 1459 break; 1460 } 1461 } 1462 } 1463 1464 // if not found, add to db 1465 bool new_to_le_device_db = false; 1466 if (le_db_index < 0) { 1467 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1468 new_to_le_device_db = true; 1469 } 1470 1471 if (le_db_index >= 0){ 1472 1473 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1474 if (!new_to_le_device_db){ 1475 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1476 } 1477 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1478 #else 1479 UNUSED(new_to_le_device_db); 1480 #endif 1481 1482 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1483 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1484 sm_conn->sm_le_db_index = le_db_index; 1485 1486 #ifdef ENABLE_LE_SIGNED_WRITE 1487 // store local CSRK 1488 setup->sm_le_device_index = le_db_index; 1489 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1490 log_info("sm: store local CSRK"); 1491 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1492 le_device_db_local_counter_set(le_db_index, 0); 1493 } 1494 1495 // store remote CSRK 1496 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1497 log_info("sm: store remote CSRK"); 1498 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1499 le_device_db_remote_counter_set(le_db_index, 0); 1500 } 1501 #endif 1502 // store encryption information for secure connections: LTK generated by ECDH 1503 if (setup->sm_use_secure_connections){ 1504 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1505 uint8_t zero_rand[8]; 1506 memset(zero_rand, 0, 8); 1507 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1508 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1509 } 1510 1511 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1512 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1513 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1514 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1515 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1516 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1517 1518 } 1519 } 1520 } 1521 1522 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1523 1524 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1525 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1526 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1527 & SM_AUTHREQ_BONDING ) != 0u; 1528 1529 if (bonding_enabled){ 1530 sm_store_bonding_information(sm_conn); 1531 } else { 1532 log_info("Ignoring received keys, bonding not enabled"); 1533 } 1534 } 1535 1536 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1537 sm_conn->sm_pairing_failed_reason = reason; 1538 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1539 } 1540 1541 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1542 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1543 } 1544 1545 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1546 1547 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1548 static int sm_passkey_used(stk_generation_method_t method); 1549 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1550 1551 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1552 if (setup->sm_stk_generation_method == OOB){ 1553 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1554 } else { 1555 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); 1556 } 1557 } 1558 1559 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1560 if (IS_RESPONDER(sm_conn->sm_role)){ 1561 // Responder 1562 if (setup->sm_stk_generation_method == OOB){ 1563 // generate Nb 1564 log_info("Generate Nb"); 1565 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); 1566 } else { 1567 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1568 } 1569 } else { 1570 // Initiator role 1571 switch (setup->sm_stk_generation_method){ 1572 case JUST_WORKS: 1573 sm_sc_prepare_dhkey_check(sm_conn); 1574 break; 1575 1576 case NUMERIC_COMPARISON: 1577 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1578 break; 1579 case PK_INIT_INPUT: 1580 case PK_RESP_INPUT: 1581 case PK_BOTH_INPUT: 1582 if (setup->sm_passkey_bit < 20u) { 1583 sm_sc_start_calculating_local_confirm(sm_conn); 1584 } else { 1585 sm_sc_prepare_dhkey_check(sm_conn); 1586 } 1587 break; 1588 case OOB: 1589 sm_sc_prepare_dhkey_check(sm_conn); 1590 break; 1591 default: 1592 btstack_assert(false); 1593 break; 1594 } 1595 } 1596 } 1597 1598 static void sm_sc_cmac_done(uint8_t * hash){ 1599 log_info("sm_sc_cmac_done: "); 1600 log_info_hexdump(hash, 16); 1601 1602 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1603 sm_sc_oob_state = SM_SC_OOB_IDLE; 1604 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1605 return; 1606 } 1607 1608 sm_connection_t * sm_conn = sm_cmac_connection; 1609 sm_cmac_connection = NULL; 1610 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1611 link_key_type_t link_key_type; 1612 #endif 1613 1614 switch (sm_conn->sm_engine_state){ 1615 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1616 (void)memcpy(setup->sm_local_confirm, hash, 16); 1617 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1618 break; 1619 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1620 // check 1621 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1622 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1623 break; 1624 } 1625 sm_sc_state_after_receiving_random(sm_conn); 1626 break; 1627 case SM_SC_W4_CALCULATE_G2: { 1628 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1629 big_endian_store_32(setup->sm_tk, 12, vab); 1630 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1631 sm_trigger_user_response(sm_conn); 1632 break; 1633 } 1634 case SM_SC_W4_CALCULATE_F5_SALT: 1635 (void)memcpy(setup->sm_t, hash, 16); 1636 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1637 break; 1638 case SM_SC_W4_CALCULATE_F5_MACKEY: 1639 (void)memcpy(setup->sm_mackey, hash, 16); 1640 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1641 break; 1642 case SM_SC_W4_CALCULATE_F5_LTK: 1643 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1644 // Errata Service Release to the Bluetooth Specification: ESR09 1645 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1646 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1647 (void)memcpy(setup->sm_ltk, hash, 16); 1648 (void)memcpy(setup->sm_local_ltk, hash, 16); 1649 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1650 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1651 break; 1652 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1653 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1654 if (IS_RESPONDER(sm_conn->sm_role)){ 1655 // responder 1656 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1657 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1658 } else { 1659 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1660 } 1661 } else { 1662 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1663 } 1664 break; 1665 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1666 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1667 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1668 break; 1669 } 1670 if (IS_RESPONDER(sm_conn->sm_role)){ 1671 // responder 1672 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1673 } else { 1674 // initiator 1675 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1676 } 1677 break; 1678 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1679 case SM_SC_W4_CALCULATE_ILK: 1680 (void)memcpy(setup->sm_t, hash, 16); 1681 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1682 break; 1683 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1684 reverse_128(hash, setup->sm_t); 1685 link_key_type = sm_conn->sm_connection_authenticated ? 1686 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1687 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1688 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1689 if (IS_RESPONDER(sm_conn->sm_role)){ 1690 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1691 } else { 1692 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1693 } 1694 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1695 sm_done_for_handle(sm_conn->sm_handle); 1696 break; 1697 case SM_BR_EDR_W4_CALCULATE_ILK: 1698 (void)memcpy(setup->sm_t, hash, 16); 1699 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1700 break; 1701 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1702 log_info("Derived LE LTK from BR/EDR Link Key"); 1703 log_info_key("Link Key", hash); 1704 (void)memcpy(setup->sm_ltk, hash, 16); 1705 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1706 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1707 sm_store_bonding_information(sm_conn); 1708 sm_done_for_handle(sm_conn->sm_handle); 1709 break; 1710 #endif 1711 default: 1712 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1713 break; 1714 } 1715 sm_trigger_run(); 1716 } 1717 1718 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){ 1719 const uint16_t message_len = 65; 1720 sm_cmac_connection = sm_conn; 1721 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1722 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1723 sm_cmac_sc_buffer[64] = z; 1724 log_info("f4 key"); 1725 log_info_hexdump(x, 16); 1726 log_info("f4 message"); 1727 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1728 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1729 } 1730 1731 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1732 static const uint8_t f5_length[] = { 0x01, 0x00}; 1733 1734 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1735 1736 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1737 1738 log_info("f5_calculate_salt"); 1739 // calculate salt for f5 1740 const uint16_t message_len = 32; 1741 sm_cmac_connection = sm_conn; 1742 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1743 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1744 } 1745 1746 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){ 1747 const uint16_t message_len = 53; 1748 sm_cmac_connection = sm_conn; 1749 1750 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1751 sm_cmac_sc_buffer[0] = 0; 1752 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1753 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1754 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1755 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1756 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1757 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1758 log_info("f5 key"); 1759 log_info_hexdump(t, 16); 1760 log_info("f5 message for MacKey"); 1761 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1762 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1763 } 1764 1765 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1766 sm_key56_t bd_addr_master, bd_addr_slave; 1767 bd_addr_master[0] = setup->sm_m_addr_type; 1768 bd_addr_slave[0] = setup->sm_s_addr_type; 1769 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1770 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1771 if (IS_RESPONDER(sm_conn->sm_role)){ 1772 // responder 1773 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1774 } else { 1775 // initiator 1776 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1777 } 1778 } 1779 1780 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1781 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1782 const uint16_t message_len = 53; 1783 sm_cmac_connection = sm_conn; 1784 sm_cmac_sc_buffer[0] = 1; 1785 // 1..52 setup before 1786 log_info("f5 key"); 1787 log_info_hexdump(t, 16); 1788 log_info("f5 message for LTK"); 1789 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1790 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1791 } 1792 1793 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1794 f5_ltk(sm_conn, setup->sm_t); 1795 } 1796 1797 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){ 1798 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1799 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1800 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1801 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1802 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1803 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1804 } 1805 1806 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1807 const uint16_t message_len = 65; 1808 sm_cmac_connection = sm_conn; 1809 log_info("f6 key"); 1810 log_info_hexdump(w, 16); 1811 log_info("f6 message"); 1812 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1813 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1814 } 1815 1816 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1817 // - U is 256 bits 1818 // - V is 256 bits 1819 // - X is 128 bits 1820 // - Y is 128 bits 1821 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){ 1822 const uint16_t message_len = 80; 1823 sm_cmac_connection = sm_conn; 1824 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1825 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1826 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1827 log_info("g2 key"); 1828 log_info_hexdump(x, 16); 1829 log_info("g2 message"); 1830 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1831 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1832 } 1833 1834 static void g2_calculate(sm_connection_t * sm_conn) { 1835 // calc Va if numeric comparison 1836 if (IS_RESPONDER(sm_conn->sm_role)){ 1837 // responder 1838 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1839 } else { 1840 // initiator 1841 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1842 } 1843 } 1844 1845 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1846 uint8_t z = 0; 1847 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1848 // some form of passkey 1849 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1850 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1851 setup->sm_passkey_bit++; 1852 } 1853 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1854 } 1855 1856 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1857 // OOB 1858 if (setup->sm_stk_generation_method == OOB){ 1859 if (IS_RESPONDER(sm_conn->sm_role)){ 1860 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1861 } else { 1862 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1863 } 1864 return; 1865 } 1866 1867 uint8_t z = 0; 1868 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1869 // some form of passkey 1870 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1871 // sm_passkey_bit was increased before sending confirm value 1872 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1873 } 1874 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1875 } 1876 1877 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1878 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1879 1880 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1881 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1882 return; 1883 } else { 1884 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1885 } 1886 } 1887 1888 static void sm_sc_dhkey_calculated(void * arg){ 1889 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1890 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1891 if (sm_conn == NULL) return; 1892 1893 log_info("dhkey"); 1894 log_info_hexdump(&setup->sm_dhkey[0], 32); 1895 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1896 // trigger next step 1897 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1898 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1899 } 1900 sm_trigger_run(); 1901 } 1902 1903 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1904 // calculate DHKCheck 1905 sm_key56_t bd_addr_master, bd_addr_slave; 1906 bd_addr_master[0] = setup->sm_m_addr_type; 1907 bd_addr_slave[0] = setup->sm_s_addr_type; 1908 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1909 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1910 uint8_t iocap_a[3]; 1911 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1912 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1913 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1914 uint8_t iocap_b[3]; 1915 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1916 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1917 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1918 if (IS_RESPONDER(sm_conn->sm_role)){ 1919 // responder 1920 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1921 f6_engine(sm_conn, setup->sm_mackey); 1922 } else { 1923 // initiator 1924 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1925 f6_engine(sm_conn, setup->sm_mackey); 1926 } 1927 } 1928 1929 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1930 // validate E = f6() 1931 sm_key56_t bd_addr_master, bd_addr_slave; 1932 bd_addr_master[0] = setup->sm_m_addr_type; 1933 bd_addr_slave[0] = setup->sm_s_addr_type; 1934 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1935 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1936 1937 uint8_t iocap_a[3]; 1938 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1939 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1940 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1941 uint8_t iocap_b[3]; 1942 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1943 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1944 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1945 if (IS_RESPONDER(sm_conn->sm_role)){ 1946 // responder 1947 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1948 f6_engine(sm_conn, setup->sm_mackey); 1949 } else { 1950 // initiator 1951 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1952 f6_engine(sm_conn, setup->sm_mackey); 1953 } 1954 } 1955 1956 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1957 1958 // 1959 // Link Key Conversion Function h6 1960 // 1961 // h6(W, keyID) = AES-CMAC_W(keyID) 1962 // - W is 128 bits 1963 // - keyID is 32 bits 1964 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1965 const uint16_t message_len = 4; 1966 sm_cmac_connection = sm_conn; 1967 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1968 log_info("h6 key"); 1969 log_info_hexdump(w, 16); 1970 log_info("h6 message"); 1971 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1972 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1973 } 1974 // 1975 // Link Key Conversion Function h7 1976 // 1977 // h7(SALT, W) = AES-CMAC_SALT(W) 1978 // - SALT is 128 bits 1979 // - W is 128 bits 1980 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1981 const uint16_t message_len = 16; 1982 sm_cmac_connection = sm_conn; 1983 log_info("h7 key"); 1984 log_info_hexdump(salt, 16); 1985 log_info("h7 message"); 1986 log_info_hexdump(w, 16); 1987 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1988 } 1989 1990 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1991 // Errata Service Release to the Bluetooth Specification: ESR09 1992 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1993 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1994 1995 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 1996 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1997 } 1998 1999 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2000 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2001 } 2002 2003 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2004 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2005 } 2006 2007 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2008 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2009 } 2010 2011 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2012 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2013 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2014 } 2015 2016 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2017 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2018 h7_engine(sm_conn, salt, setup->sm_link_key); 2019 } 2020 2021 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2022 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2023 btstack_assert(hci_connection != NULL); 2024 reverse_128(hci_connection->link_key, setup->sm_link_key); 2025 setup->sm_link_key_type = hci_connection->link_key_type; 2026 } 2027 2028 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2029 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; 2030 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2031 } 2032 2033 #endif 2034 2035 #endif 2036 2037 // key management legacy connections: 2038 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2039 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2040 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2041 // - responder reconnects: responder uses LTK receveived from master 2042 2043 // key management secure connections: 2044 // - both devices store same LTK from ECDH key exchange. 2045 2046 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2047 static void sm_load_security_info(sm_connection_t * sm_connection){ 2048 int encryption_key_size; 2049 int authenticated; 2050 int authorized; 2051 int secure_connection; 2052 2053 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2054 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2055 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2056 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); 2057 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2058 sm_connection->sm_connection_authenticated = authenticated; 2059 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2060 sm_connection->sm_connection_sc = secure_connection; 2061 } 2062 #endif 2063 2064 #ifdef ENABLE_LE_PERIPHERAL 2065 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2066 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2067 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2068 // re-establish used key encryption size 2069 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2070 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2071 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2072 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2073 // Legacy paring -> not SC 2074 sm_connection->sm_connection_sc = 0; 2075 log_info("sm: received ltk request with key size %u, authenticated %u", 2076 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2077 } 2078 #endif 2079 2080 // distributed key generation 2081 static bool sm_run_dpkg(void){ 2082 switch (dkg_state){ 2083 case DKG_CALC_IRK: 2084 // already busy? 2085 if (sm_aes128_state == SM_AES128_IDLE) { 2086 log_info("DKG_CALC_IRK started"); 2087 // IRK = d1(IR, 1, 0) 2088 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2089 sm_aes128_state = SM_AES128_ACTIVE; 2090 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2091 return true; 2092 } 2093 break; 2094 case DKG_CALC_DHK: 2095 // already busy? 2096 if (sm_aes128_state == SM_AES128_IDLE) { 2097 log_info("DKG_CALC_DHK started"); 2098 // DHK = d1(IR, 3, 0) 2099 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2100 sm_aes128_state = SM_AES128_ACTIVE; 2101 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2102 return true; 2103 } 2104 break; 2105 default: 2106 break; 2107 } 2108 return false; 2109 } 2110 2111 // random address updates 2112 static bool sm_run_rau(void){ 2113 switch (rau_state){ 2114 case RAU_GET_RANDOM: 2115 rau_state = RAU_W4_RANDOM; 2116 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2117 return true; 2118 case RAU_GET_ENC: 2119 // already busy? 2120 if (sm_aes128_state == SM_AES128_IDLE) { 2121 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2122 sm_aes128_state = SM_AES128_ACTIVE; 2123 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2124 return true; 2125 } 2126 break; 2127 default: 2128 break; 2129 } 2130 return false; 2131 } 2132 2133 // CSRK Lookup 2134 static bool sm_run_csrk(void){ 2135 btstack_linked_list_iterator_t it; 2136 2137 // -- if csrk lookup ready, find connection that require csrk lookup 2138 if (sm_address_resolution_idle()){ 2139 hci_connections_get_iterator(&it); 2140 while(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 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2144 // and start lookup 2145 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); 2146 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2147 break; 2148 } 2149 } 2150 } 2151 2152 // -- if csrk lookup ready, resolved addresses for received addresses 2153 if (sm_address_resolution_idle()) { 2154 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2155 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2156 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2157 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2158 btstack_memory_sm_lookup_entry_free(entry); 2159 } 2160 } 2161 2162 // -- Continue with CSRK device lookup by public or resolvable private address 2163 if (!sm_address_resolution_idle()){ 2164 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2165 while (sm_address_resolution_test < le_device_db_max_count()){ 2166 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2167 bd_addr_t addr; 2168 sm_key_t irk; 2169 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2170 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2171 2172 // skip unused entries 2173 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2174 sm_address_resolution_test++; 2175 continue; 2176 } 2177 2178 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2179 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2180 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2181 break; 2182 } 2183 2184 // if connection type is public, it must be a different one 2185 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2186 sm_address_resolution_test++; 2187 continue; 2188 } 2189 2190 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2191 2192 log_info("LE Device Lookup: calculate AH"); 2193 log_info_key("IRK", irk); 2194 2195 (void)memcpy(sm_aes128_key, irk, 16); 2196 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2197 sm_address_resolution_ah_calculation_active = 1; 2198 sm_aes128_state = SM_AES128_ACTIVE; 2199 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2200 return true; 2201 } 2202 2203 if (sm_address_resolution_test >= le_device_db_max_count()){ 2204 log_info("LE Device Lookup: not found"); 2205 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2206 } 2207 } 2208 return false; 2209 } 2210 2211 // SC OOB 2212 static bool sm_run_oob(void){ 2213 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2214 switch (sm_sc_oob_state){ 2215 case SM_SC_OOB_W2_CALC_CONFIRM: 2216 if (!sm_cmac_ready()) break; 2217 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2218 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2219 return true; 2220 default: 2221 break; 2222 } 2223 #endif 2224 return false; 2225 } 2226 2227 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2228 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2229 } 2230 2231 // handle basic actions that don't requires the full context 2232 static bool sm_run_basic(void){ 2233 btstack_linked_list_iterator_t it; 2234 hci_connections_get_iterator(&it); 2235 while(btstack_linked_list_iterator_has_next(&it)){ 2236 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2237 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2238 switch(sm_connection->sm_engine_state){ 2239 2240 // general 2241 case SM_GENERAL_SEND_PAIRING_FAILED: { 2242 uint8_t buffer[2]; 2243 buffer[0] = SM_CODE_PAIRING_FAILED; 2244 buffer[1] = sm_connection->sm_pairing_failed_reason; 2245 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2246 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2247 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2248 sm_done_for_handle(sm_connection->sm_handle); 2249 break; 2250 } 2251 2252 // responder side 2253 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2254 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2255 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2256 return true; 2257 2258 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2259 case SM_SC_RECEIVED_LTK_REQUEST: 2260 switch (sm_connection->sm_irk_lookup_state){ 2261 case IRK_LOOKUP_FAILED: 2262 log_info("LTK Request: IRK Lookup Failed)"); 2263 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2264 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2265 return true; 2266 default: 2267 break; 2268 } 2269 break; 2270 #endif 2271 default: 2272 break; 2273 } 2274 } 2275 return false; 2276 } 2277 2278 static void sm_run_activate_connection(void){ 2279 // Find connections that requires setup context and make active if no other is locked 2280 btstack_linked_list_iterator_t it; 2281 hci_connections_get_iterator(&it); 2282 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2283 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2284 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2285 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2286 bool done = true; 2287 int err; 2288 UNUSED(err); 2289 2290 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2291 // assert ec key is ready 2292 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2293 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2294 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2295 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2296 sm_ec_generate_new_key(); 2297 } 2298 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2299 continue; 2300 } 2301 } 2302 #endif 2303 2304 switch (sm_connection->sm_engine_state) { 2305 #ifdef ENABLE_LE_PERIPHERAL 2306 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2307 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2308 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2309 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2310 case SM_SC_RECEIVED_LTK_REQUEST: 2311 #endif 2312 #endif 2313 #ifdef ENABLE_LE_CENTRAL 2314 case SM_INITIATOR_PH4_HAS_LTK: 2315 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2316 #endif 2317 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2318 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2319 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2320 #endif 2321 // just lock context 2322 break; 2323 default: 2324 done = false; 2325 break; 2326 } 2327 if (done){ 2328 sm_active_connection_handle = sm_connection->sm_handle; 2329 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); 2330 } 2331 } 2332 } 2333 2334 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2335 int i; 2336 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2337 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2338 uint8_t action = 0; 2339 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2340 if (flags & (1u<<i)){ 2341 bool clear_flag = true; 2342 switch (i){ 2343 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2344 case SM_KEYPRESS_PASSKEY_CLEARED: 2345 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2346 default: 2347 break; 2348 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2349 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2350 num_actions--; 2351 clear_flag = num_actions == 0u; 2352 break; 2353 } 2354 if (clear_flag){ 2355 flags &= ~(1<<i); 2356 } 2357 action = i; 2358 break; 2359 } 2360 } 2361 setup->sm_keypress_notification = (num_actions << 5) | flags; 2362 2363 // send keypress notification 2364 uint8_t buffer[2]; 2365 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2366 buffer[1] = action; 2367 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2368 2369 // try 2370 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2371 } 2372 2373 static void sm_run_distribute_keys(sm_connection_t * connection){ 2374 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2375 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2376 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2377 uint8_t buffer[17]; 2378 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2379 reverse_128(setup->sm_ltk, &buffer[1]); 2380 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2381 sm_timeout_reset(connection); 2382 return; 2383 } 2384 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2385 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2386 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2387 uint8_t buffer[11]; 2388 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2389 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2390 reverse_64(setup->sm_local_rand, &buffer[3]); 2391 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2392 sm_timeout_reset(connection); 2393 return; 2394 } 2395 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2396 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2397 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2398 uint8_t buffer[17]; 2399 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2400 reverse_128(sm_persistent_irk, &buffer[1]); 2401 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2402 sm_timeout_reset(connection); 2403 return; 2404 } 2405 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2406 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2407 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2408 bd_addr_t local_address; 2409 uint8_t buffer[8]; 2410 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2411 switch (gap_random_address_get_mode()){ 2412 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2413 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2414 // public or static random 2415 gap_le_get_own_address(&buffer[1], local_address); 2416 break; 2417 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2418 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2419 // fallback to public 2420 gap_local_bd_addr(local_address); 2421 buffer[1] = 0; 2422 break; 2423 default: 2424 btstack_assert(false); 2425 break; 2426 } 2427 reverse_bd_addr(local_address, &buffer[2]); 2428 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2429 sm_timeout_reset(connection); 2430 return; 2431 } 2432 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2433 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2434 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2435 2436 #ifdef ENABLE_LE_SIGNED_WRITE 2437 // hack to reproduce test runs 2438 if (test_use_fixed_local_csrk){ 2439 memset(setup->sm_local_csrk, 0xcc, 16); 2440 } 2441 2442 // store local CSRK 2443 if (setup->sm_le_device_index >= 0){ 2444 log_info("sm: store local CSRK"); 2445 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2446 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2447 } 2448 #endif 2449 2450 uint8_t buffer[17]; 2451 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2452 reverse_128(setup->sm_local_csrk, &buffer[1]); 2453 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2454 sm_timeout_reset(connection); 2455 return; 2456 } 2457 btstack_assert(false); 2458 } 2459 2460 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2461 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2462 // requirements to derive link key from LE: 2463 // - use secure connections 2464 if (setup->sm_use_secure_connections == 0) return false; 2465 // - bonding needs to be enabled: 2466 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; 2467 if (!bonding_enabled) return false; 2468 // - need identity address / public addr 2469 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2470 if (!have_identity_address_info) return false; 2471 // - 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) 2472 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2473 // If SC is authenticated, we consider it safe to overwrite a stored key. 2474 // 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. 2475 uint8_t link_key[16]; 2476 link_key_type_t link_key_type; 2477 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2478 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 2479 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2480 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2481 return false; 2482 } 2483 // get started (all of the above are true) 2484 return true; 2485 #else 2486 UNUSED(sm_connection); 2487 return false; 2488 #endif 2489 } 2490 2491 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2492 if (sm_ctkd_from_le(connection)){ 2493 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; 2494 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2495 } else { 2496 connection->sm_engine_state = SM_RESPONDER_IDLE; 2497 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2498 sm_done_for_handle(connection->sm_handle); 2499 } 2500 } 2501 2502 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2503 if (sm_ctkd_from_le(connection)){ 2504 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; 2505 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2506 } else { 2507 sm_master_pairing_success(connection); 2508 } 2509 } 2510 2511 static void sm_run(void){ 2512 2513 // assert that stack has already bootet 2514 if (hci_get_state() != HCI_STATE_WORKING) return; 2515 2516 // assert that we can send at least commands 2517 if (!hci_can_send_command_packet_now()) return; 2518 2519 // pause until IR/ER are ready 2520 if (sm_persistent_keys_random_active) return; 2521 2522 bool done; 2523 2524 // 2525 // non-connection related behaviour 2526 // 2527 2528 done = sm_run_dpkg(); 2529 if (done) return; 2530 2531 done = sm_run_rau(); 2532 if (done) return; 2533 2534 done = sm_run_csrk(); 2535 if (done) return; 2536 2537 done = sm_run_oob(); 2538 if (done) return; 2539 2540 // assert that we can send at least commands - cmd might have been sent by crypto engine 2541 if (!hci_can_send_command_packet_now()) return; 2542 2543 // handle basic actions that don't requires the full context 2544 done = sm_run_basic(); 2545 if (done) return; 2546 2547 // 2548 // active connection handling 2549 // -- use loop to handle next connection if lock on setup context is released 2550 2551 while (true) { 2552 2553 sm_run_activate_connection(); 2554 2555 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2556 2557 // 2558 // active connection handling 2559 // 2560 2561 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2562 if (!connection) { 2563 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2564 return; 2565 } 2566 2567 // assert that we could send a SM PDU - not needed for all of the following 2568 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2569 log_info("cannot send now, requesting can send now event"); 2570 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2571 return; 2572 } 2573 2574 // send keypress notifications 2575 if (setup->sm_keypress_notification){ 2576 sm_run_send_keypress_notification(connection); 2577 return; 2578 } 2579 2580 int key_distribution_flags; 2581 UNUSED(key_distribution_flags); 2582 int err; 2583 UNUSED(err); 2584 bool have_ltk; 2585 uint8_t ltk[16]; 2586 2587 log_info("sm_run: state %u", connection->sm_engine_state); 2588 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2589 log_info("sm_run // cannot send"); 2590 } 2591 switch (connection->sm_engine_state){ 2592 2593 // secure connections, initiator + responding states 2594 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2595 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2596 if (!sm_cmac_ready()) break; 2597 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2598 sm_sc_calculate_local_confirm(connection); 2599 break; 2600 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2601 if (!sm_cmac_ready()) break; 2602 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2603 sm_sc_calculate_remote_confirm(connection); 2604 break; 2605 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2606 if (!sm_cmac_ready()) break; 2607 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2608 sm_sc_calculate_f6_for_dhkey_check(connection); 2609 break; 2610 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2611 if (!sm_cmac_ready()) break; 2612 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2613 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2614 break; 2615 case SM_SC_W2_CALCULATE_F5_SALT: 2616 if (!sm_cmac_ready()) break; 2617 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2618 f5_calculate_salt(connection); 2619 break; 2620 case SM_SC_W2_CALCULATE_F5_MACKEY: 2621 if (!sm_cmac_ready()) break; 2622 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2623 f5_calculate_mackey(connection); 2624 break; 2625 case SM_SC_W2_CALCULATE_F5_LTK: 2626 if (!sm_cmac_ready()) break; 2627 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2628 f5_calculate_ltk(connection); 2629 break; 2630 case SM_SC_W2_CALCULATE_G2: 2631 if (!sm_cmac_ready()) break; 2632 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2633 g2_calculate(connection); 2634 break; 2635 #endif 2636 2637 #ifdef ENABLE_LE_CENTRAL 2638 // initiator side 2639 2640 case SM_INITIATOR_PH4_HAS_LTK: { 2641 sm_reset_setup(); 2642 sm_load_security_info(connection); 2643 sm_reencryption_started(connection); 2644 2645 sm_key_t peer_ltk_flipped; 2646 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2647 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2648 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2649 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2650 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2651 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2652 return; 2653 } 2654 2655 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2656 sm_reset_setup(); 2657 sm_init_setup(connection); 2658 sm_timeout_start(connection); 2659 sm_pairing_started(connection); 2660 2661 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2662 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2663 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2664 sm_timeout_reset(connection); 2665 break; 2666 #endif 2667 2668 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2669 2670 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2671 bool trigger_user_response = false; 2672 bool trigger_start_calculating_local_confirm = false; 2673 uint8_t buffer[65]; 2674 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2675 // 2676 reverse_256(&ec_q[0], &buffer[1]); 2677 reverse_256(&ec_q[32], &buffer[33]); 2678 2679 #ifdef ENABLE_TESTING_SUPPORT 2680 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2681 log_info("testing_support: invalidating public key"); 2682 // flip single bit of public key coordinate 2683 buffer[1] ^= 1; 2684 } 2685 #endif 2686 2687 // stk generation method 2688 // passkey entry: notify app to show passkey or to request passkey 2689 switch (setup->sm_stk_generation_method){ 2690 case JUST_WORKS: 2691 case NUMERIC_COMPARISON: 2692 if (IS_RESPONDER(connection->sm_role)){ 2693 // responder 2694 trigger_start_calculating_local_confirm = true; 2695 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2696 } else { 2697 // initiator 2698 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2699 } 2700 break; 2701 case PK_INIT_INPUT: 2702 case PK_RESP_INPUT: 2703 case PK_BOTH_INPUT: 2704 // use random TK for display 2705 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2706 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2707 setup->sm_passkey_bit = 0; 2708 2709 if (IS_RESPONDER(connection->sm_role)){ 2710 // responder 2711 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2712 } else { 2713 // initiator 2714 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2715 } 2716 trigger_user_response = true; 2717 break; 2718 case OOB: 2719 if (IS_RESPONDER(connection->sm_role)){ 2720 // responder 2721 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2722 } else { 2723 // initiator 2724 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2725 } 2726 break; 2727 default: 2728 btstack_assert(false); 2729 break; 2730 } 2731 2732 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2733 sm_timeout_reset(connection); 2734 2735 // trigger user response and calc confirm after sending pdu 2736 if (trigger_user_response){ 2737 sm_trigger_user_response(connection); 2738 } 2739 if (trigger_start_calculating_local_confirm){ 2740 sm_sc_start_calculating_local_confirm(connection); 2741 } 2742 break; 2743 } 2744 case SM_SC_SEND_CONFIRMATION: { 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_SC_W4_PAIRING_RANDOM; 2750 } else { 2751 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2752 } 2753 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2754 sm_timeout_reset(connection); 2755 break; 2756 } 2757 case SM_SC_SEND_PAIRING_RANDOM: { 2758 uint8_t buffer[17]; 2759 buffer[0] = SM_CODE_PAIRING_RANDOM; 2760 reverse_128(setup->sm_local_nonce, &buffer[1]); 2761 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2762 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2763 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2764 if (IS_RESPONDER(connection->sm_role)){ 2765 // responder 2766 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2767 } else { 2768 // initiator 2769 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2770 } 2771 } else { 2772 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2773 if (IS_RESPONDER(connection->sm_role)){ 2774 // responder 2775 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2776 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2777 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2778 } else { 2779 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2780 sm_sc_prepare_dhkey_check(connection); 2781 } 2782 } else { 2783 // initiator 2784 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2785 } 2786 } 2787 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2788 sm_timeout_reset(connection); 2789 break; 2790 } 2791 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2792 uint8_t buffer[17]; 2793 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2794 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2795 2796 if (IS_RESPONDER(connection->sm_role)){ 2797 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2798 } else { 2799 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2800 } 2801 2802 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2803 sm_timeout_reset(connection); 2804 break; 2805 } 2806 2807 #endif 2808 2809 #ifdef ENABLE_LE_PERIPHERAL 2810 2811 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2812 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2813 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2814 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2815 sm_timeout_start(connection); 2816 break; 2817 } 2818 2819 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2820 case SM_SC_RECEIVED_LTK_REQUEST: 2821 switch (connection->sm_irk_lookup_state){ 2822 case IRK_LOOKUP_SUCCEEDED: 2823 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2824 // start using context by loading security info 2825 sm_reset_setup(); 2826 sm_load_security_info(connection); 2827 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2828 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2829 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2830 sm_reencryption_started(connection); 2831 sm_trigger_run(); 2832 break; 2833 } 2834 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2835 connection->sm_engine_state = SM_RESPONDER_IDLE; 2836 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2837 return; 2838 default: 2839 // just wait until IRK lookup is completed 2840 break; 2841 } 2842 break; 2843 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2844 2845 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2846 sm_reset_setup(); 2847 2848 // handle Pairing Request with LTK available 2849 switch (connection->sm_irk_lookup_state) { 2850 case IRK_LOOKUP_SUCCEEDED: 2851 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2852 have_ltk = !sm_is_null_key(ltk); 2853 if (have_ltk){ 2854 log_info("pairing request but LTK available"); 2855 // emit re-encryption start/fail sequence 2856 sm_reencryption_started(connection); 2857 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2858 } 2859 break; 2860 default: 2861 break; 2862 } 2863 2864 sm_init_setup(connection); 2865 sm_pairing_started(connection); 2866 2867 // recover pairing request 2868 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2869 err = sm_stk_generation_init(connection); 2870 2871 #ifdef ENABLE_TESTING_SUPPORT 2872 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2873 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2874 err = test_pairing_failure; 2875 } 2876 #endif 2877 if (err != 0){ 2878 sm_pairing_error(connection, err); 2879 sm_trigger_run(); 2880 break; 2881 } 2882 2883 sm_timeout_start(connection); 2884 2885 // generate random number first, if we need to show passkey, otherwise send response 2886 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2887 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2888 break; 2889 } 2890 2891 /* fall through */ 2892 2893 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2894 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2895 2896 // start with initiator key dist flags 2897 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2898 2899 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2900 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2901 if (setup->sm_use_secure_connections){ 2902 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2903 } 2904 #endif 2905 // setup in response 2906 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); 2907 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); 2908 2909 // update key distribution after ENC was dropped 2910 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres), sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 2911 2912 if (setup->sm_use_secure_connections){ 2913 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2914 } else { 2915 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2916 } 2917 2918 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2919 sm_timeout_reset(connection); 2920 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2921 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2922 sm_trigger_user_response(connection); 2923 } 2924 return; 2925 #endif 2926 2927 case SM_PH2_SEND_PAIRING_RANDOM: { 2928 uint8_t buffer[17]; 2929 buffer[0] = SM_CODE_PAIRING_RANDOM; 2930 reverse_128(setup->sm_local_random, &buffer[1]); 2931 if (IS_RESPONDER(connection->sm_role)){ 2932 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2933 } else { 2934 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2935 } 2936 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2937 sm_timeout_reset(connection); 2938 break; 2939 } 2940 2941 case SM_PH2_C1_GET_ENC_A: 2942 // already busy? 2943 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2944 // calculate confirm using aes128 engine - step 1 2945 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); 2946 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2947 sm_aes128_state = SM_AES128_ACTIVE; 2948 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); 2949 break; 2950 2951 case SM_PH2_C1_GET_ENC_C: 2952 // already busy? 2953 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2954 // calculate m_confirm using aes128 engine - step 1 2955 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); 2956 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2957 sm_aes128_state = SM_AES128_ACTIVE; 2958 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); 2959 break; 2960 2961 case SM_PH2_CALC_STK: 2962 // already busy? 2963 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2964 // calculate STK 2965 if (IS_RESPONDER(connection->sm_role)){ 2966 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2967 } else { 2968 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2969 } 2970 connection->sm_engine_state = SM_PH2_W4_STK; 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 break; 2974 2975 case SM_PH3_Y_GET_ENC: 2976 // already busy? 2977 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2978 // PH3B2 - calculate Y from - enc 2979 2980 // dm helper (was sm_dm_r_prime) 2981 // r' = padding || r 2982 // r - 64 bit value 2983 memset(&sm_aes128_plaintext[0], 0, 8); 2984 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2985 2986 // Y = dm(DHK, Rand) 2987 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2988 sm_aes128_state = SM_AES128_ACTIVE; 2989 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); 2990 break; 2991 2992 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2993 uint8_t buffer[17]; 2994 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2995 reverse_128(setup->sm_local_confirm, &buffer[1]); 2996 if (IS_RESPONDER(connection->sm_role)){ 2997 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2998 } else { 2999 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3000 } 3001 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3002 sm_timeout_reset(connection); 3003 return; 3004 } 3005 #ifdef ENABLE_LE_PERIPHERAL 3006 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3007 sm_key_t stk_flipped; 3008 reverse_128(setup->sm_ltk, stk_flipped); 3009 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3010 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3011 return; 3012 } 3013 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3014 sm_key_t ltk_flipped; 3015 reverse_128(setup->sm_ltk, ltk_flipped); 3016 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3017 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3018 return; 3019 } 3020 3021 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3022 // already busy? 3023 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3024 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3025 3026 sm_reset_setup(); 3027 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3028 3029 sm_reencryption_started(connection); 3030 3031 // dm helper (was sm_dm_r_prime) 3032 // r' = padding || r 3033 // r - 64 bit value 3034 memset(&sm_aes128_plaintext[0], 0, 8); 3035 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3036 3037 // Y = dm(DHK, Rand) 3038 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3039 sm_aes128_state = SM_AES128_ACTIVE; 3040 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); 3041 return; 3042 #endif 3043 #ifdef ENABLE_LE_CENTRAL 3044 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3045 sm_key_t stk_flipped; 3046 reverse_128(setup->sm_ltk, stk_flipped); 3047 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3048 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3049 return; 3050 } 3051 #endif 3052 3053 case SM_PH3_DISTRIBUTE_KEYS: 3054 if (setup->sm_key_distribution_send_set != 0){ 3055 sm_run_distribute_keys(connection); 3056 return; 3057 } 3058 3059 // keys are sent 3060 if (IS_RESPONDER(connection->sm_role)){ 3061 // slave -> receive master keys if any 3062 if (sm_key_distribution_all_received()){ 3063 sm_key_distribution_handle_all_received(connection); 3064 sm_key_distribution_complete_responder(connection); 3065 // start CTKD right away 3066 continue; 3067 } else { 3068 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3069 } 3070 } else { 3071 sm_master_pairing_success(connection); 3072 } 3073 break; 3074 3075 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3076 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3077 // fill in sm setup (lite version of sm_init_setup) 3078 sm_reset_setup(); 3079 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3080 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3081 setup->sm_s_addr_type = connection->sm_own_addr_type; 3082 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3083 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3084 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3085 setup->sm_use_secure_connections = true; 3086 sm_ctkd_fetch_br_edr_link_key(connection); 3087 3088 // Enc Key and IRK if requested 3089 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3090 #ifdef ENABLE_LE_SIGNED_WRITE 3091 // Plus signing key if supported 3092 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3093 #endif 3094 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3095 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3096 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3097 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3098 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3099 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3100 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3101 3102 // set state and send pairing response 3103 sm_timeout_start(connection); 3104 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3105 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3106 break; 3107 3108 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3109 // fill in sm setup (lite version of sm_init_setup) 3110 sm_reset_setup(); 3111 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3112 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3113 setup->sm_s_addr_type = connection->sm_own_addr_type; 3114 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3115 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3116 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3117 setup->sm_use_secure_connections = true; 3118 sm_ctkd_fetch_br_edr_link_key(connection); 3119 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3120 3121 // Enc Key and IRK if requested 3122 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3123 #ifdef ENABLE_LE_SIGNED_WRITE 3124 // Plus signing key if supported 3125 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3126 #endif 3127 // drop flags not requested by initiator 3128 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3129 3130 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3131 // - the IO Capability field, 3132 // - the OOB data flag field, and 3133 // - all bits in the Auth Req field except the CT2 bit. 3134 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3135 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3136 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3137 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3138 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3139 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3140 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3141 3142 // configure key distribution, LTK is derived locally 3143 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3144 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3145 3146 // set state and send pairing response 3147 sm_timeout_start(connection); 3148 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3149 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3150 break; 3151 case SM_BR_EDR_DISTRIBUTE_KEYS: 3152 if (setup->sm_key_distribution_send_set != 0) { 3153 sm_run_distribute_keys(connection); 3154 return; 3155 } 3156 // keys are sent 3157 if (IS_RESPONDER(connection->sm_role)) { 3158 // responder -> receive master keys if there are any 3159 if (!sm_key_distribution_all_received()){ 3160 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3161 break; 3162 } 3163 } 3164 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3165 sm_ctkd_start_from_br_edr(connection); 3166 continue; 3167 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3168 if (!sm_cmac_ready()) break; 3169 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3170 h6_calculate_ilk_from_le_ltk(connection); 3171 break; 3172 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3173 if (!sm_cmac_ready()) break; 3174 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3175 h6_calculate_br_edr_link_key(connection); 3176 break; 3177 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3178 if (!sm_cmac_ready()) break; 3179 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3180 h7_calculate_ilk_from_le_ltk(connection); 3181 break; 3182 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3183 if (!sm_cmac_ready()) break; 3184 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3185 h6_calculate_ilk_from_br_edr(connection); 3186 break; 3187 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3188 if (!sm_cmac_ready()) break; 3189 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3190 h6_calculate_le_ltk(connection); 3191 break; 3192 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3193 if (!sm_cmac_ready()) break; 3194 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3195 h7_calculate_ilk_from_br_edr(connection); 3196 break; 3197 #endif 3198 3199 default: 3200 break; 3201 } 3202 3203 // check again if active connection was released 3204 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3205 } 3206 } 3207 3208 // sm_aes128_state stays active 3209 static void sm_handle_encryption_result_enc_a(void *arg){ 3210 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3211 sm_aes128_state = SM_AES128_IDLE; 3212 3213 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3214 if (connection == NULL) return; 3215 3216 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3217 sm_aes128_state = SM_AES128_ACTIVE; 3218 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); 3219 } 3220 3221 static void sm_handle_encryption_result_enc_b(void *arg){ 3222 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3223 sm_aes128_state = SM_AES128_IDLE; 3224 3225 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3226 if (connection == NULL) return; 3227 3228 log_info_key("c1!", setup->sm_local_confirm); 3229 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3230 sm_trigger_run(); 3231 } 3232 3233 // sm_aes128_state stays active 3234 static void sm_handle_encryption_result_enc_c(void *arg){ 3235 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3236 sm_aes128_state = SM_AES128_IDLE; 3237 3238 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3239 if (connection == NULL) return; 3240 3241 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3242 sm_aes128_state = SM_AES128_ACTIVE; 3243 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); 3244 } 3245 3246 static void sm_handle_encryption_result_enc_d(void * arg){ 3247 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3248 sm_aes128_state = SM_AES128_IDLE; 3249 3250 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3251 if (connection == NULL) return; 3252 3253 log_info_key("c1!", sm_aes128_ciphertext); 3254 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3255 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3256 sm_trigger_run(); 3257 return; 3258 } 3259 if (IS_RESPONDER(connection->sm_role)){ 3260 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3261 sm_trigger_run(); 3262 } else { 3263 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3264 sm_aes128_state = SM_AES128_ACTIVE; 3265 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); 3266 } 3267 } 3268 3269 static void sm_handle_encryption_result_enc_stk(void *arg){ 3270 sm_aes128_state = SM_AES128_IDLE; 3271 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3272 3273 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3274 if (connection == NULL) return; 3275 3276 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3277 log_info_key("stk", setup->sm_ltk); 3278 if (IS_RESPONDER(connection->sm_role)){ 3279 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3280 } else { 3281 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3282 } 3283 sm_trigger_run(); 3284 } 3285 3286 // sm_aes128_state stays active 3287 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3288 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3289 sm_aes128_state = SM_AES128_IDLE; 3290 3291 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3292 if (connection == NULL) return; 3293 3294 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3295 log_info_hex16("y", setup->sm_local_y); 3296 // PH3B3 - calculate EDIV 3297 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3298 log_info_hex16("ediv", setup->sm_local_ediv); 3299 // PH3B4 - calculate LTK - enc 3300 // LTK = d1(ER, DIV, 0)) 3301 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3302 sm_aes128_state = SM_AES128_ACTIVE; 3303 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); 3304 } 3305 3306 #ifdef ENABLE_LE_PERIPHERAL 3307 // sm_aes128_state stays active 3308 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3309 sm_aes128_state = SM_AES128_IDLE; 3310 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3311 3312 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3313 if (connection == NULL) return; 3314 3315 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3316 log_info_hex16("y", setup->sm_local_y); 3317 3318 // PH3B3 - calculate DIV 3319 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3320 log_info_hex16("ediv", setup->sm_local_ediv); 3321 // PH3B4 - calculate LTK - enc 3322 // LTK = d1(ER, DIV, 0)) 3323 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3324 sm_aes128_state = SM_AES128_ACTIVE; 3325 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); 3326 } 3327 #endif 3328 3329 // sm_aes128_state stays active 3330 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3331 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3332 sm_aes128_state = SM_AES128_IDLE; 3333 3334 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3335 if (connection == NULL) return; 3336 3337 log_info_key("ltk", setup->sm_ltk); 3338 // calc CSRK next 3339 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3340 sm_aes128_state = SM_AES128_ACTIVE; 3341 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); 3342 } 3343 3344 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3345 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3346 sm_aes128_state = SM_AES128_IDLE; 3347 3348 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3349 if (connection == NULL) return; 3350 3351 sm_aes128_state = SM_AES128_IDLE; 3352 log_info_key("csrk", setup->sm_local_csrk); 3353 if (setup->sm_key_distribution_send_set){ 3354 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3355 } else { 3356 // no keys to send, just continue 3357 if (IS_RESPONDER(connection->sm_role)){ 3358 if (sm_key_distribution_all_received()){ 3359 sm_key_distribution_handle_all_received(connection); 3360 sm_key_distribution_complete_responder(connection); 3361 } else { 3362 // slave -> receive master keys 3363 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3364 } 3365 } else { 3366 sm_key_distribution_complete_initiator(connection); 3367 } 3368 } 3369 sm_trigger_run(); 3370 } 3371 3372 #ifdef ENABLE_LE_PERIPHERAL 3373 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3374 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3375 sm_aes128_state = SM_AES128_IDLE; 3376 3377 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3378 if (connection == NULL) return; 3379 3380 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3381 log_info_key("ltk", setup->sm_ltk); 3382 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3383 sm_trigger_run(); 3384 } 3385 #endif 3386 3387 static void sm_handle_encryption_result_address_resolution(void *arg){ 3388 UNUSED(arg); 3389 sm_aes128_state = SM_AES128_IDLE; 3390 3391 sm_address_resolution_ah_calculation_active = 0; 3392 // compare calulated address against connecting device 3393 uint8_t * hash = &sm_aes128_ciphertext[13]; 3394 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3395 log_info("LE Device Lookup: matched resolvable private address"); 3396 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3397 sm_trigger_run(); 3398 return; 3399 } 3400 // no match, try next 3401 sm_address_resolution_test++; 3402 sm_trigger_run(); 3403 } 3404 3405 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3406 UNUSED(arg); 3407 sm_aes128_state = SM_AES128_IDLE; 3408 3409 log_info_key("irk", sm_persistent_irk); 3410 dkg_state = DKG_CALC_DHK; 3411 sm_trigger_run(); 3412 } 3413 3414 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3415 UNUSED(arg); 3416 sm_aes128_state = SM_AES128_IDLE; 3417 3418 log_info_key("dhk", sm_persistent_dhk); 3419 dkg_state = DKG_READY; 3420 sm_trigger_run(); 3421 } 3422 3423 static void sm_handle_encryption_result_rau(void *arg){ 3424 UNUSED(arg); 3425 sm_aes128_state = SM_AES128_IDLE; 3426 3427 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3428 rau_state = RAU_IDLE; 3429 hci_le_random_address_set(sm_random_address); 3430 3431 sm_trigger_run(); 3432 } 3433 3434 static void sm_handle_random_result_rau(void * arg){ 3435 UNUSED(arg); 3436 // non-resolvable vs. resolvable 3437 switch (gap_random_adress_type){ 3438 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3439 // resolvable: use random as prand and calc address hash 3440 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3441 sm_random_address[0u] &= 0x3fu; 3442 sm_random_address[0u] |= 0x40u; 3443 rau_state = RAU_GET_ENC; 3444 break; 3445 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3446 default: 3447 // "The two most significant bits of the address shall be equal to ‘0’"" 3448 sm_random_address[0u] &= 0x3fu; 3449 hci_le_random_address_set(sm_random_address); 3450 break; 3451 } 3452 sm_trigger_run(); 3453 } 3454 3455 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3456 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3457 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3458 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3459 if (connection == NULL) return; 3460 3461 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3462 sm_trigger_run(); 3463 } 3464 3465 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3466 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3467 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3468 if (connection == NULL) return; 3469 3470 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3471 sm_trigger_run(); 3472 } 3473 #endif 3474 3475 static void sm_handle_random_result_ph2_random(void * arg){ 3476 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3477 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3478 if (connection == NULL) return; 3479 3480 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3481 sm_trigger_run(); 3482 } 3483 3484 static void sm_handle_random_result_ph2_tk(void * arg){ 3485 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3486 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3487 if (connection == NULL) return; 3488 3489 sm_reset_tk(); 3490 uint32_t tk; 3491 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3492 // map random to 0-999999 without speding much cycles on a modulus operation 3493 tk = little_endian_read_32(sm_random_data,0); 3494 tk = tk & 0xfffff; // 1048575 3495 if (tk >= 999999u){ 3496 tk = tk - 999999u; 3497 } 3498 } else { 3499 // override with pre-defined passkey 3500 tk = sm_fixed_passkey_in_display_role; 3501 } 3502 big_endian_store_32(setup->sm_tk, 12, tk); 3503 if (IS_RESPONDER(connection->sm_role)){ 3504 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3505 } else { 3506 if (setup->sm_use_secure_connections){ 3507 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3508 } else { 3509 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3510 sm_trigger_user_response(connection); 3511 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3512 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3513 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); 3514 } 3515 } 3516 } 3517 sm_trigger_run(); 3518 } 3519 3520 static void sm_handle_random_result_ph3_div(void * arg){ 3521 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3522 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3523 if (connection == NULL) return; 3524 3525 // use 16 bit from random value as div 3526 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3527 log_info_hex16("div", setup->sm_local_div); 3528 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3529 sm_trigger_run(); 3530 } 3531 3532 static void sm_handle_random_result_ph3_random(void * arg){ 3533 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3534 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3535 if (connection == NULL) return; 3536 3537 reverse_64(sm_random_data, setup->sm_local_rand); 3538 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3539 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3540 // no db for authenticated flag hack: store flag in bit 4 of LSB 3541 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3542 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3543 } 3544 static void sm_validate_er_ir(void){ 3545 // warn about default ER/IR 3546 bool warning = false; 3547 if (sm_ir_is_default()){ 3548 warning = true; 3549 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3550 } 3551 if (sm_er_is_default()){ 3552 warning = true; 3553 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3554 } 3555 if (warning) { 3556 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3557 } 3558 } 3559 3560 static void sm_handle_random_result_ir(void *arg){ 3561 sm_persistent_keys_random_active = false; 3562 if (arg != NULL){ 3563 // key generated, store in tlv 3564 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3565 log_info("Generated IR key. Store in TLV status: %d", status); 3566 UNUSED(status); 3567 } 3568 log_info_key("IR", sm_persistent_ir); 3569 dkg_state = DKG_CALC_IRK; 3570 3571 if (test_use_fixed_local_irk){ 3572 log_info_key("IRK", sm_persistent_irk); 3573 dkg_state = DKG_CALC_DHK; 3574 } 3575 3576 sm_trigger_run(); 3577 } 3578 3579 static void sm_handle_random_result_er(void *arg){ 3580 sm_persistent_keys_random_active = false; 3581 if (arg != 0){ 3582 // key generated, store in tlv 3583 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3584 log_info("Generated ER key. Store in TLV status: %d", status); 3585 UNUSED(status); 3586 } 3587 log_info_key("ER", sm_persistent_er); 3588 3589 // try load ir 3590 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3591 if (key_size == 16){ 3592 // ok, let's continue 3593 log_info("IR from TLV"); 3594 sm_handle_random_result_ir( NULL ); 3595 } else { 3596 // invalid, generate new random one 3597 sm_persistent_keys_random_active = true; 3598 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3599 } 3600 } 3601 3602 static void sm_connection_init(sm_connection_t * sm_conn, hci_con_handle_t con_handle, uint8_t role, uint8_t addr_type, bd_addr_t address){ 3603 3604 // connection info 3605 sm_conn->sm_handle = con_handle; 3606 sm_conn->sm_role = role; 3607 sm_conn->sm_peer_addr_type = addr_type; 3608 memcpy(sm_conn->sm_peer_address, address, 6); 3609 3610 // security properties 3611 sm_conn->sm_connection_encrypted = 0; 3612 sm_conn->sm_connection_authenticated = 0; 3613 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3614 sm_conn->sm_le_db_index = -1; 3615 sm_conn->sm_reencryption_active = false; 3616 3617 // prepare CSRK lookup (does not involve setup) 3618 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3619 3620 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3621 } 3622 3623 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3624 3625 UNUSED(channel); // ok: there is no channel 3626 UNUSED(size); // ok: fixed format HCI events 3627 3628 sm_connection_t * sm_conn; 3629 hci_con_handle_t con_handle; 3630 uint8_t status; 3631 bd_addr_t addr; 3632 3633 switch (packet_type) { 3634 3635 case HCI_EVENT_PACKET: 3636 switch (hci_event_packet_get_type(packet)) { 3637 3638 case BTSTACK_EVENT_STATE: 3639 // bt stack activated, get started 3640 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3641 log_info("HCI Working!"); 3642 3643 // setup IR/ER with TLV 3644 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3645 if (sm_tlv_impl != NULL){ 3646 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3647 if (key_size == 16){ 3648 // ok, let's continue 3649 log_info("ER from TLV"); 3650 sm_handle_random_result_er( NULL ); 3651 } else { 3652 // invalid, generate random one 3653 sm_persistent_keys_random_active = true; 3654 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3655 } 3656 } else { 3657 sm_validate_er_ir(); 3658 dkg_state = DKG_CALC_IRK; 3659 3660 if (test_use_fixed_local_irk){ 3661 log_info_key("IRK", sm_persistent_irk); 3662 dkg_state = DKG_CALC_DHK; 3663 } 3664 } 3665 3666 // restart random address updates after power cycle 3667 gap_random_address_set_mode(gap_random_adress_type); 3668 } 3669 break; 3670 3671 #ifdef ENABLE_CLASSIC 3672 case HCI_EVENT_CONNECTION_COMPLETE: 3673 // ignore if connection failed 3674 if (hci_event_connection_complete_get_status(packet)) return; 3675 3676 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3677 sm_conn = sm_get_connection_for_handle(con_handle); 3678 if (!sm_conn) break; 3679 3680 hci_event_connection_complete_get_bd_addr(packet, addr); 3681 sm_connection_init(sm_conn, 3682 con_handle, 3683 (uint8_t) gap_get_role(con_handle), 3684 BD_ADDR_TYPE_LE_PUBLIC, 3685 addr); 3686 // classic connection corresponds to public le address 3687 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3688 gap_local_bd_addr(sm_conn->sm_own_address); 3689 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3690 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3691 break; 3692 #endif 3693 3694 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3695 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3696 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3697 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3698 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3699 if (sm_conn == NULL) break; 3700 sm_conn->sm_pairing_requested = 1; 3701 break; 3702 #endif 3703 3704 case HCI_EVENT_LE_META: 3705 switch (packet[2]) { 3706 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3707 // ignore if connection failed 3708 if (packet[3]) return; 3709 3710 con_handle = little_endian_read_16(packet, 4); 3711 sm_conn = sm_get_connection_for_handle(con_handle); 3712 if (!sm_conn) break; 3713 3714 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3715 sm_connection_init(sm_conn, 3716 con_handle, 3717 hci_subevent_le_connection_complete_get_role(packet), 3718 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3719 addr); 3720 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3721 3722 // track our addr used for this connection and set state 3723 #ifdef ENABLE_LE_CENTRAL 3724 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3725 // responder - use own address from advertisements 3726 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3727 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3728 } 3729 #endif 3730 #ifdef ENABLE_LE_CENTRAL 3731 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3732 // initiator - use own address from create connection 3733 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3734 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3735 } 3736 #endif 3737 break; 3738 3739 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3740 con_handle = little_endian_read_16(packet, 3); 3741 sm_conn = sm_get_connection_for_handle(con_handle); 3742 if (!sm_conn) break; 3743 3744 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3745 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3746 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3747 break; 3748 } 3749 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3750 // PH2 SEND LTK as we need to exchange keys in PH3 3751 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3752 break; 3753 } 3754 3755 // store rand and ediv 3756 reverse_64(&packet[5], sm_conn->sm_local_rand); 3757 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3758 3759 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3760 // potentially stored LTK is from the master 3761 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3762 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3763 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3764 break; 3765 } 3766 // additionally check if remote is in LE Device DB if requested 3767 switch(sm_conn->sm_irk_lookup_state){ 3768 case IRK_LOOKUP_FAILED: 3769 log_info("LTK Request: device not in device db"); 3770 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3771 break; 3772 case IRK_LOOKUP_SUCCEEDED: 3773 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3774 break; 3775 default: 3776 // wait for irk look doen 3777 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3778 break; 3779 } 3780 break; 3781 } 3782 3783 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3784 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3785 #else 3786 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3787 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3788 #endif 3789 break; 3790 3791 default: 3792 break; 3793 } 3794 break; 3795 3796 case HCI_EVENT_ENCRYPTION_CHANGE: 3797 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3798 sm_conn = sm_get_connection_for_handle(con_handle); 3799 if (!sm_conn) break; 3800 3801 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3802 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3803 sm_conn->sm_actual_encryption_key_size); 3804 log_info("event handler, state %u", sm_conn->sm_engine_state); 3805 3806 switch (sm_conn->sm_engine_state){ 3807 3808 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3809 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3810 if (sm_conn->sm_connection_encrypted) { 3811 status = ERROR_CODE_SUCCESS; 3812 if (sm_conn->sm_role){ 3813 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3814 } else { 3815 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3816 } 3817 } else { 3818 status = hci_event_encryption_change_get_status(packet); 3819 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3820 // also, gap_reconnect_security_setup_active will return true 3821 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3822 } 3823 3824 // emit re-encryption complete 3825 sm_reencryption_complete(sm_conn, status); 3826 3827 // notify client, if pairing was requested before 3828 if (sm_conn->sm_pairing_requested){ 3829 sm_conn->sm_pairing_requested = 0; 3830 sm_pairing_complete(sm_conn, status, 0); 3831 } 3832 3833 sm_done_for_handle(sm_conn->sm_handle); 3834 break; 3835 3836 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3837 if (!sm_conn->sm_connection_encrypted) break; 3838 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3839 if (IS_RESPONDER(sm_conn->sm_role)){ 3840 // slave 3841 if (setup->sm_use_secure_connections){ 3842 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3843 } else { 3844 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); 3845 } 3846 } else { 3847 // master 3848 if (sm_key_distribution_all_received()){ 3849 // skip receiving keys as there are none 3850 sm_key_distribution_handle_all_received(sm_conn); 3851 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); 3852 } else { 3853 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3854 } 3855 } 3856 break; 3857 3858 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3859 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3860 if (sm_conn->sm_connection_encrypted != 2) break; 3861 // prepare for pairing request 3862 if (IS_RESPONDER(sm_conn->sm_role)){ 3863 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3864 } else if (sm_conn->sm_pairing_requested){ 3865 // only send LE pairing request after BR/EDR SSP 3866 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3867 } 3868 break; 3869 #endif 3870 default: 3871 break; 3872 } 3873 break; 3874 3875 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3876 con_handle = little_endian_read_16(packet, 3); 3877 sm_conn = sm_get_connection_for_handle(con_handle); 3878 if (!sm_conn) break; 3879 3880 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3881 log_info("event handler, state %u", sm_conn->sm_engine_state); 3882 // continue if part of initial pairing 3883 switch (sm_conn->sm_engine_state){ 3884 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3885 if (sm_conn->sm_role){ 3886 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3887 } else { 3888 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3889 } 3890 sm_done_for_handle(sm_conn->sm_handle); 3891 break; 3892 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3893 if (IS_RESPONDER(sm_conn->sm_role)){ 3894 // slave 3895 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); 3896 } else { 3897 // master 3898 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3899 } 3900 break; 3901 default: 3902 break; 3903 } 3904 break; 3905 3906 3907 case HCI_EVENT_DISCONNECTION_COMPLETE: 3908 con_handle = little_endian_read_16(packet, 3); 3909 sm_done_for_handle(con_handle); 3910 sm_conn = sm_get_connection_for_handle(con_handle); 3911 if (!sm_conn) break; 3912 3913 // pairing failed, if it was ongoing 3914 switch (sm_conn->sm_engine_state){ 3915 case SM_GENERAL_IDLE: 3916 case SM_INITIATOR_CONNECTED: 3917 case SM_RESPONDER_IDLE: 3918 break; 3919 default: 3920 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3921 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3922 break; 3923 } 3924 3925 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3926 sm_conn->sm_handle = 0; 3927 break; 3928 3929 case HCI_EVENT_COMMAND_COMPLETE: 3930 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)) { 3931 // set local addr for le device db 3932 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3933 le_device_db_set_local_bd_addr(addr); 3934 } 3935 break; 3936 default: 3937 break; 3938 } 3939 break; 3940 default: 3941 break; 3942 } 3943 3944 sm_run(); 3945 } 3946 3947 static inline int sm_calc_actual_encryption_key_size(int other){ 3948 if (other < sm_min_encryption_key_size) return 0; 3949 if (other < sm_max_encryption_key_size) return other; 3950 return sm_max_encryption_key_size; 3951 } 3952 3953 3954 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3955 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3956 switch (method){ 3957 case JUST_WORKS: 3958 case NUMERIC_COMPARISON: 3959 return 1; 3960 default: 3961 return 0; 3962 } 3963 } 3964 // responder 3965 3966 static int sm_passkey_used(stk_generation_method_t method){ 3967 switch (method){ 3968 case PK_RESP_INPUT: 3969 return 1; 3970 default: 3971 return 0; 3972 } 3973 } 3974 3975 static int sm_passkey_entry(stk_generation_method_t method){ 3976 switch (method){ 3977 case PK_RESP_INPUT: 3978 case PK_INIT_INPUT: 3979 case PK_BOTH_INPUT: 3980 return 1; 3981 default: 3982 return 0; 3983 } 3984 } 3985 3986 #endif 3987 3988 /** 3989 * @return ok 3990 */ 3991 static int sm_validate_stk_generation_method(void){ 3992 // check if STK generation method is acceptable by client 3993 switch (setup->sm_stk_generation_method){ 3994 case JUST_WORKS: 3995 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3996 case PK_RESP_INPUT: 3997 case PK_INIT_INPUT: 3998 case PK_BOTH_INPUT: 3999 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4000 case OOB: 4001 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4002 case NUMERIC_COMPARISON: 4003 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4004 default: 4005 return 0; 4006 } 4007 } 4008 4009 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4010 4011 // size of complete sm_pdu used to validate input 4012 static const uint8_t sm_pdu_size[] = { 4013 0, // 0x00 invalid opcode 4014 7, // 0x01 pairing request 4015 7, // 0x02 pairing response 4016 17, // 0x03 pairing confirm 4017 17, // 0x04 pairing random 4018 2, // 0x05 pairing failed 4019 17, // 0x06 encryption information 4020 11, // 0x07 master identification 4021 17, // 0x08 identification information 4022 8, // 0x09 identify address information 4023 17, // 0x0a signing information 4024 2, // 0x0b security request 4025 65, // 0x0c pairing public key 4026 17, // 0x0d pairing dhk check 4027 2, // 0x0e keypress notification 4028 }; 4029 4030 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4031 sm_run(); 4032 } 4033 4034 if (packet_type != SM_DATA_PACKET) return; 4035 if (size == 0u) return; 4036 4037 uint8_t sm_pdu_code = packet[0]; 4038 4039 // validate pdu size 4040 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 4041 if (sm_pdu_size[sm_pdu_code] != size) return; 4042 4043 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4044 if (!sm_conn) return; 4045 4046 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4047 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4048 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4049 sm_done_for_handle(con_handle); 4050 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4051 return; 4052 } 4053 4054 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4055 4056 int err; 4057 UNUSED(err); 4058 4059 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4060 uint8_t buffer[5]; 4061 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4062 buffer[1] = 3; 4063 little_endian_store_16(buffer, 2, con_handle); 4064 buffer[4] = packet[1]; 4065 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4066 return; 4067 } 4068 4069 #ifdef ENABLE_LE_CENTRAL 4070 int have_ltk; 4071 uint8_t ltk[16]; 4072 #endif 4073 4074 switch (sm_conn->sm_engine_state){ 4075 4076 // a sm timeout requires a new physical connection 4077 case SM_GENERAL_TIMEOUT: 4078 return; 4079 4080 #ifdef ENABLE_LE_CENTRAL 4081 4082 // Initiator 4083 case SM_INITIATOR_CONNECTED: 4084 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4085 sm_pdu_received_in_wrong_state(sm_conn); 4086 break; 4087 } 4088 4089 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4090 if (sm_sc_only_mode){ 4091 uint8_t auth_req = packet[1]; 4092 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4093 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4094 break; 4095 } 4096 } 4097 #endif 4098 4099 // IRK complete? 4100 switch (sm_conn->sm_irk_lookup_state){ 4101 case IRK_LOOKUP_FAILED: 4102 // start pairing 4103 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4104 break; 4105 case IRK_LOOKUP_SUCCEEDED: 4106 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4107 have_ltk = !sm_is_null_key(ltk); 4108 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4109 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4110 // start re-encrypt if we have LTK and the connection is not already encrypted 4111 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4112 } else { 4113 // start pairing 4114 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4115 } 4116 break; 4117 default: 4118 // otherwise, store security request 4119 sm_conn->sm_security_request_received = 1; 4120 break; 4121 } 4122 break; 4123 4124 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4125 // Core 5, Vol 3, Part H, 2.4.6: 4126 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4127 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4128 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4129 log_info("Ignoring Security Request"); 4130 break; 4131 } 4132 4133 // all other pdus are incorrect 4134 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4135 sm_pdu_received_in_wrong_state(sm_conn); 4136 break; 4137 } 4138 4139 // store pairing request 4140 (void)memcpy(&setup->sm_s_pres, packet, 4141 sizeof(sm_pairing_packet_t)); 4142 err = sm_stk_generation_init(sm_conn); 4143 4144 #ifdef ENABLE_TESTING_SUPPORT 4145 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4146 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4147 err = test_pairing_failure; 4148 } 4149 #endif 4150 4151 if (err != 0){ 4152 sm_pairing_error(sm_conn, err); 4153 break; 4154 } 4155 4156 // generate random number first, if we need to show passkey 4157 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4158 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); 4159 break; 4160 } 4161 4162 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4163 if (setup->sm_use_secure_connections){ 4164 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4165 if (setup->sm_stk_generation_method == JUST_WORKS){ 4166 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4167 sm_trigger_user_response(sm_conn); 4168 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4169 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4170 } 4171 } else { 4172 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4173 } 4174 break; 4175 } 4176 #endif 4177 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4178 sm_trigger_user_response(sm_conn); 4179 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4180 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4181 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); 4182 } 4183 break; 4184 4185 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4186 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4187 sm_pdu_received_in_wrong_state(sm_conn); 4188 break; 4189 } 4190 4191 // store s_confirm 4192 reverse_128(&packet[1], setup->sm_peer_confirm); 4193 4194 // abort if s_confirm matches m_confirm 4195 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4196 sm_pdu_received_in_wrong_state(sm_conn); 4197 break; 4198 } 4199 4200 #ifdef ENABLE_TESTING_SUPPORT 4201 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4202 log_info("testing_support: reset confirm value"); 4203 memset(setup->sm_peer_confirm, 0, 16); 4204 } 4205 #endif 4206 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4207 break; 4208 4209 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4210 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4211 sm_pdu_received_in_wrong_state(sm_conn); 4212 break;; 4213 } 4214 4215 // received random value 4216 reverse_128(&packet[1], setup->sm_peer_random); 4217 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4218 break; 4219 #endif 4220 4221 #ifdef ENABLE_LE_PERIPHERAL 4222 // Responder 4223 case SM_RESPONDER_IDLE: 4224 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4225 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4226 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4227 sm_pdu_received_in_wrong_state(sm_conn); 4228 break;; 4229 } 4230 4231 // store pairing request 4232 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4233 4234 // check if IRK completed 4235 switch (sm_conn->sm_irk_lookup_state){ 4236 case IRK_LOOKUP_SUCCEEDED: 4237 case IRK_LOOKUP_FAILED: 4238 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4239 break; 4240 default: 4241 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4242 break; 4243 } 4244 break; 4245 #endif 4246 4247 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4248 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4249 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4250 sm_pdu_received_in_wrong_state(sm_conn); 4251 break; 4252 } 4253 4254 // store public key for DH Key calculation 4255 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4256 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4257 4258 // CVE-2020-26558: abort pairing if remote uses the same public key 4259 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4260 log_info("Remote PK matches ours"); 4261 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4262 break; 4263 } 4264 4265 // validate public key 4266 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4267 if (err != 0){ 4268 log_info("sm: peer public key invalid %x", err); 4269 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4270 break; 4271 } 4272 4273 // start calculating dhkey 4274 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); 4275 4276 4277 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4278 if (IS_RESPONDER(sm_conn->sm_role)){ 4279 // responder 4280 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4281 } else { 4282 // initiator 4283 // stk generation method 4284 // passkey entry: notify app to show passkey or to request passkey 4285 switch (setup->sm_stk_generation_method){ 4286 case JUST_WORKS: 4287 case NUMERIC_COMPARISON: 4288 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4289 break; 4290 case PK_RESP_INPUT: 4291 sm_sc_start_calculating_local_confirm(sm_conn); 4292 break; 4293 case PK_INIT_INPUT: 4294 case PK_BOTH_INPUT: 4295 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4296 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4297 break; 4298 } 4299 sm_sc_start_calculating_local_confirm(sm_conn); 4300 break; 4301 case OOB: 4302 // generate Nx 4303 log_info("Generate Na"); 4304 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); 4305 break; 4306 default: 4307 btstack_assert(false); 4308 break; 4309 } 4310 } 4311 break; 4312 4313 case SM_SC_W4_CONFIRMATION: 4314 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4315 sm_pdu_received_in_wrong_state(sm_conn); 4316 break; 4317 } 4318 // received confirm value 4319 reverse_128(&packet[1], setup->sm_peer_confirm); 4320 4321 #ifdef ENABLE_TESTING_SUPPORT 4322 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4323 log_info("testing_support: reset confirm value"); 4324 memset(setup->sm_peer_confirm, 0, 16); 4325 } 4326 #endif 4327 if (IS_RESPONDER(sm_conn->sm_role)){ 4328 // responder 4329 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4330 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4331 // still waiting for passkey 4332 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4333 break; 4334 } 4335 } 4336 sm_sc_start_calculating_local_confirm(sm_conn); 4337 } else { 4338 // initiator 4339 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4340 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); 4341 } else { 4342 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4343 } 4344 } 4345 break; 4346 4347 case SM_SC_W4_PAIRING_RANDOM: 4348 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4349 sm_pdu_received_in_wrong_state(sm_conn); 4350 break; 4351 } 4352 4353 // received random value 4354 reverse_128(&packet[1], setup->sm_peer_nonce); 4355 4356 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4357 // only check for JUST WORK/NC in initiator role OR passkey entry 4358 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4359 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4360 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4361 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4362 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4363 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4364 break; 4365 } 4366 4367 // OOB 4368 if (setup->sm_stk_generation_method == OOB){ 4369 4370 // setup local random, set to zero if remote did not receive our data 4371 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4372 if (IS_RESPONDER(sm_conn->sm_role)){ 4373 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4374 log_info("Reset rb as A does not have OOB data"); 4375 memset(setup->sm_rb, 0, 16); 4376 } else { 4377 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4378 log_info("Use stored rb"); 4379 log_info_hexdump(setup->sm_rb, 16); 4380 } 4381 } else { 4382 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4383 log_info("Reset ra as B does not have OOB data"); 4384 memset(setup->sm_ra, 0, 16); 4385 } else { 4386 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4387 log_info("Use stored ra"); 4388 log_info_hexdump(setup->sm_ra, 16); 4389 } 4390 } 4391 4392 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4393 if (setup->sm_have_oob_data){ 4394 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4395 break; 4396 } 4397 } 4398 4399 // TODO: we only get here for Responder role with JW/NC 4400 sm_sc_state_after_receiving_random(sm_conn); 4401 break; 4402 4403 case SM_SC_W2_CALCULATE_G2: 4404 case SM_SC_W4_CALCULATE_G2: 4405 case SM_SC_W4_CALCULATE_DHKEY: 4406 case SM_SC_W2_CALCULATE_F5_SALT: 4407 case SM_SC_W4_CALCULATE_F5_SALT: 4408 case SM_SC_W2_CALCULATE_F5_MACKEY: 4409 case SM_SC_W4_CALCULATE_F5_MACKEY: 4410 case SM_SC_W2_CALCULATE_F5_LTK: 4411 case SM_SC_W4_CALCULATE_F5_LTK: 4412 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4413 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4414 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4415 case SM_SC_W4_USER_RESPONSE: 4416 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4417 sm_pdu_received_in_wrong_state(sm_conn); 4418 break; 4419 } 4420 // store DHKey Check 4421 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4422 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4423 4424 // have we been only waiting for dhkey check command? 4425 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4426 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4427 } 4428 break; 4429 #endif 4430 4431 #ifdef ENABLE_LE_PERIPHERAL 4432 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4433 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4434 sm_pdu_received_in_wrong_state(sm_conn); 4435 break; 4436 } 4437 4438 // received confirm value 4439 reverse_128(&packet[1], setup->sm_peer_confirm); 4440 4441 #ifdef ENABLE_TESTING_SUPPORT 4442 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4443 log_info("testing_support: reset confirm value"); 4444 memset(setup->sm_peer_confirm, 0, 16); 4445 } 4446 #endif 4447 // notify client to hide shown passkey 4448 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4449 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4450 } 4451 4452 // handle user cancel pairing? 4453 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4454 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4455 break; 4456 } 4457 4458 // wait for user action? 4459 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4460 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4461 break; 4462 } 4463 4464 // calculate and send local_confirm 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 break; 4467 4468 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4469 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4470 sm_pdu_received_in_wrong_state(sm_conn); 4471 break;; 4472 } 4473 4474 // received random value 4475 reverse_128(&packet[1], setup->sm_peer_random); 4476 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4477 break; 4478 #endif 4479 4480 case SM_PH3_RECEIVE_KEYS: 4481 switch(sm_pdu_code){ 4482 case SM_CODE_ENCRYPTION_INFORMATION: 4483 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4484 reverse_128(&packet[1], setup->sm_peer_ltk); 4485 break; 4486 4487 case SM_CODE_MASTER_IDENTIFICATION: 4488 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4489 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4490 reverse_64(&packet[3], setup->sm_peer_rand); 4491 break; 4492 4493 case SM_CODE_IDENTITY_INFORMATION: 4494 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4495 reverse_128(&packet[1], setup->sm_peer_irk); 4496 break; 4497 4498 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4499 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4500 setup->sm_peer_addr_type = packet[1]; 4501 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4502 break; 4503 4504 case SM_CODE_SIGNING_INFORMATION: 4505 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4506 reverse_128(&packet[1], setup->sm_peer_csrk); 4507 break; 4508 default: 4509 // Unexpected PDU 4510 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4511 break; 4512 } 4513 // done with key distribution? 4514 if (sm_key_distribution_all_received()){ 4515 4516 sm_key_distribution_handle_all_received(sm_conn); 4517 4518 if (IS_RESPONDER(sm_conn->sm_role)){ 4519 sm_key_distribution_complete_responder(sm_conn); 4520 } else { 4521 if (setup->sm_use_secure_connections){ 4522 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4523 } else { 4524 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); 4525 } 4526 } 4527 } 4528 break; 4529 4530 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4531 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4532 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4533 sm_pdu_received_in_wrong_state(sm_conn); 4534 break; 4535 } 4536 // store pairing response 4537 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4538 4539 // validate encryption key size 4540 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres)); 4541 // SC Only mandates 128 bit key size 4542 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4543 sm_conn->sm_actual_encryption_key_size = 0; 4544 } 4545 if (sm_conn->sm_actual_encryption_key_size == 0){ 4546 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4547 break; 4548 } 4549 4550 // prepare key exchange, LTK is derived locally 4551 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4552 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4553 4554 // skip receive if there are none 4555 if (sm_key_distribution_all_received()){ 4556 // distribute keys in run handles 'no keys to send' 4557 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4558 } else { 4559 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4560 } 4561 break; 4562 4563 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4564 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4565 sm_pdu_received_in_wrong_state(sm_conn); 4566 break; 4567 } 4568 // store pairing request 4569 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4570 // validate encryption key size 4571 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq)); 4572 // SC Only mandates 128 bit key size 4573 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4574 sm_conn->sm_actual_encryption_key_size = 0; 4575 } 4576 if (sm_conn->sm_actual_encryption_key_size == 0){ 4577 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4578 break; 4579 } 4580 // trigger response 4581 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4582 break; 4583 4584 case SM_BR_EDR_RECEIVE_KEYS: 4585 switch(sm_pdu_code){ 4586 case SM_CODE_IDENTITY_INFORMATION: 4587 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4588 reverse_128(&packet[1], setup->sm_peer_irk); 4589 break; 4590 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4591 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4592 setup->sm_peer_addr_type = packet[1]; 4593 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4594 break; 4595 case SM_CODE_SIGNING_INFORMATION: 4596 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4597 reverse_128(&packet[1], setup->sm_peer_csrk); 4598 break; 4599 default: 4600 // Unexpected PDU 4601 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4602 break; 4603 } 4604 4605 // all keys received 4606 if (sm_key_distribution_all_received()){ 4607 if (IS_RESPONDER(sm_conn->sm_role)){ 4608 // responder -> keys exchanged, derive LE LTK 4609 sm_ctkd_start_from_br_edr(sm_conn); 4610 } else { 4611 // initiator -> send our keys if any 4612 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4613 } 4614 } 4615 break; 4616 #endif 4617 4618 default: 4619 // Unexpected PDU 4620 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4621 sm_pdu_received_in_wrong_state(sm_conn); 4622 break; 4623 } 4624 4625 // try to send next pdu 4626 sm_trigger_run(); 4627 } 4628 4629 // Security Manager Client API 4630 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4631 sm_get_oob_data = get_oob_data_callback; 4632 } 4633 4634 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)){ 4635 sm_get_sc_oob_data = get_sc_oob_data_callback; 4636 } 4637 4638 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4639 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4640 } 4641 4642 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4643 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4644 } 4645 4646 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4647 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4648 } 4649 4650 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4651 sm_min_encryption_key_size = min_size; 4652 sm_max_encryption_key_size = max_size; 4653 } 4654 4655 void sm_set_authentication_requirements(uint8_t auth_req){ 4656 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4657 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4658 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4659 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4660 } 4661 #endif 4662 sm_auth_req = auth_req; 4663 } 4664 4665 void sm_set_io_capabilities(io_capability_t io_capability){ 4666 sm_io_capabilities = io_capability; 4667 } 4668 4669 #ifdef ENABLE_LE_PERIPHERAL 4670 void sm_set_request_security(int enable){ 4671 sm_slave_request_security = enable; 4672 } 4673 #endif 4674 4675 void sm_set_er(sm_key_t er){ 4676 (void)memcpy(sm_persistent_er, er, 16); 4677 } 4678 4679 void sm_set_ir(sm_key_t ir){ 4680 (void)memcpy(sm_persistent_ir, ir, 16); 4681 } 4682 4683 // Testing support only 4684 void sm_test_set_irk(sm_key_t irk){ 4685 (void)memcpy(sm_persistent_irk, irk, 16); 4686 dkg_state = DKG_CALC_DHK; 4687 test_use_fixed_local_irk = true; 4688 } 4689 4690 void sm_test_use_fixed_local_csrk(void){ 4691 test_use_fixed_local_csrk = true; 4692 } 4693 4694 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4695 static void sm_ec_generated(void * arg){ 4696 UNUSED(arg); 4697 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4698 // trigger pairing if pending for ec key 4699 sm_trigger_run(); 4700 } 4701 static void sm_ec_generate_new_key(void){ 4702 log_info("sm: generate new ec key"); 4703 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4704 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4705 } 4706 #endif 4707 4708 #ifdef ENABLE_TESTING_SUPPORT 4709 void sm_test_set_pairing_failure(int reason){ 4710 test_pairing_failure = reason; 4711 } 4712 #endif 4713 4714 void sm_init(void){ 4715 4716 if (sm_initialized) return; 4717 4718 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4719 sm_er_ir_set_default(); 4720 4721 // defaults 4722 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4723 | SM_STK_GENERATION_METHOD_OOB 4724 | SM_STK_GENERATION_METHOD_PASSKEY 4725 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4726 4727 sm_max_encryption_key_size = 16; 4728 sm_min_encryption_key_size = 7; 4729 4730 sm_fixed_passkey_in_display_role = 0xffffffffU; 4731 sm_reconstruct_ltk_without_le_device_db_entry = true; 4732 4733 #ifdef USE_CMAC_ENGINE 4734 sm_cmac_active = 0; 4735 #endif 4736 dkg_state = DKG_W4_WORKING; 4737 rau_state = RAU_IDLE; 4738 sm_aes128_state = SM_AES128_IDLE; 4739 sm_address_resolution_test = -1; // no private address to resolve yet 4740 sm_address_resolution_ah_calculation_active = 0; 4741 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4742 sm_address_resolution_general_queue = NULL; 4743 4744 gap_random_adress_update_period = 15 * 60 * 1000L; 4745 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4746 4747 test_use_fixed_local_csrk = false; 4748 4749 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4750 4751 // register for HCI Events from HCI 4752 hci_event_callback_registration.callback = &sm_event_packet_handler; 4753 hci_add_event_handler(&hci_event_callback_registration); 4754 4755 // 4756 btstack_crypto_init(); 4757 4758 // init le_device_db 4759 le_device_db_init(); 4760 4761 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4762 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4763 4764 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4765 sm_ec_generate_new_key(); 4766 #endif 4767 4768 sm_initialized = true; 4769 } 4770 4771 void sm_deinit(void){ 4772 sm_initialized = false; 4773 btstack_run_loop_remove_timer(&sm_run_timer); 4774 } 4775 4776 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4777 sm_fixed_passkey_in_display_role = passkey; 4778 } 4779 4780 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4781 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4782 } 4783 4784 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4785 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4786 if (!hci_con) return NULL; 4787 return &hci_con->sm_connection; 4788 } 4789 4790 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4791 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4792 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4793 if (!hci_con) return NULL; 4794 return &hci_con->sm_connection; 4795 } 4796 #endif 4797 4798 // @deprecated: map onto sm_request_pairing 4799 void sm_send_security_request(hci_con_handle_t con_handle){ 4800 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4801 if (!sm_conn) return; 4802 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4803 sm_request_pairing(con_handle); 4804 } 4805 4806 // request pairing 4807 void sm_request_pairing(hci_con_handle_t con_handle){ 4808 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4809 if (!sm_conn) return; // wrong connection 4810 4811 bool have_ltk; 4812 uint8_t ltk[16]; 4813 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4814 if (IS_RESPONDER(sm_conn->sm_role)){ 4815 switch (sm_conn->sm_engine_state){ 4816 case SM_GENERAL_IDLE: 4817 case SM_RESPONDER_IDLE: 4818 switch (sm_conn->sm_irk_lookup_state){ 4819 case IRK_LOOKUP_SUCCEEDED: 4820 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4821 have_ltk = !sm_is_null_key(ltk); 4822 log_info("have ltk %u", have_ltk); 4823 if (have_ltk){ 4824 sm_conn->sm_pairing_requested = 1; 4825 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4826 sm_reencryption_started(sm_conn); 4827 break; 4828 } 4829 /* fall through */ 4830 4831 case IRK_LOOKUP_FAILED: 4832 sm_conn->sm_pairing_requested = 1; 4833 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4834 sm_pairing_started(sm_conn); 4835 break; 4836 default: 4837 log_info("irk lookup pending"); 4838 sm_conn->sm_pairing_requested = 1; 4839 break; 4840 } 4841 break; 4842 default: 4843 break; 4844 } 4845 } else { 4846 // used as a trigger to start central/master/initiator security procedures 4847 switch (sm_conn->sm_engine_state){ 4848 case SM_INITIATOR_CONNECTED: 4849 switch (sm_conn->sm_irk_lookup_state){ 4850 case IRK_LOOKUP_SUCCEEDED: 4851 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4852 have_ltk = !sm_is_null_key(ltk); 4853 log_info("have ltk %u", have_ltk); 4854 if (have_ltk){ 4855 sm_conn->sm_pairing_requested = 1; 4856 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4857 break; 4858 } 4859 /* fall through */ 4860 4861 case IRK_LOOKUP_FAILED: 4862 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4863 break; 4864 default: 4865 log_info("irk lookup pending"); 4866 sm_conn->sm_pairing_requested = 1; 4867 break; 4868 } 4869 break; 4870 case SM_GENERAL_REENCRYPTION_FAILED: 4871 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4872 break; 4873 case SM_GENERAL_IDLE: 4874 sm_conn->sm_pairing_requested = 1; 4875 break; 4876 default: 4877 break; 4878 } 4879 } 4880 sm_trigger_run(); 4881 } 4882 4883 // called by client app on authorization request 4884 void sm_authorization_decline(hci_con_handle_t con_handle){ 4885 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4886 if (!sm_conn) return; // wrong connection 4887 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4888 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4889 } 4890 4891 void sm_authorization_grant(hci_con_handle_t con_handle){ 4892 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4893 if (!sm_conn) return; // wrong connection 4894 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4895 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4896 } 4897 4898 // GAP Bonding API 4899 4900 void sm_bonding_decline(hci_con_handle_t con_handle){ 4901 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4902 if (!sm_conn) return; // wrong connection 4903 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4904 log_info("decline, state %u", sm_conn->sm_engine_state); 4905 switch(sm_conn->sm_engine_state){ 4906 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4907 case SM_SC_W4_USER_RESPONSE: 4908 case SM_SC_W4_CONFIRMATION: 4909 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4910 #endif 4911 case SM_PH1_W4_USER_RESPONSE: 4912 switch (setup->sm_stk_generation_method){ 4913 case PK_RESP_INPUT: 4914 case PK_INIT_INPUT: 4915 case PK_BOTH_INPUT: 4916 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4917 break; 4918 case NUMERIC_COMPARISON: 4919 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4920 break; 4921 case JUST_WORKS: 4922 case OOB: 4923 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4924 break; 4925 default: 4926 btstack_assert(false); 4927 break; 4928 } 4929 break; 4930 default: 4931 break; 4932 } 4933 sm_trigger_run(); 4934 } 4935 4936 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4937 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4938 if (!sm_conn) return; // wrong connection 4939 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4940 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4941 if (setup->sm_use_secure_connections){ 4942 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4943 } else { 4944 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); 4945 } 4946 } 4947 4948 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4949 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4950 sm_sc_prepare_dhkey_check(sm_conn); 4951 } 4952 #endif 4953 4954 sm_trigger_run(); 4955 } 4956 4957 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4958 // for now, it's the same 4959 sm_just_works_confirm(con_handle); 4960 } 4961 4962 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4963 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4964 if (!sm_conn) return; // wrong connection 4965 sm_reset_tk(); 4966 big_endian_store_32(setup->sm_tk, 12, passkey); 4967 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4968 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4969 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); 4970 } 4971 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4972 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4973 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4974 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4975 sm_sc_start_calculating_local_confirm(sm_conn); 4976 } 4977 #endif 4978 sm_trigger_run(); 4979 } 4980 4981 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4982 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4983 if (!sm_conn) return; // wrong connection 4984 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4985 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4986 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4987 switch (action){ 4988 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4989 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4990 flags |= (1u << action); 4991 break; 4992 case SM_KEYPRESS_PASSKEY_CLEARED: 4993 // clear counter, keypress & erased flags + set passkey cleared 4994 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4995 break; 4996 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4997 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4998 // erase actions queued 4999 num_actions--; 5000 if (num_actions == 0u){ 5001 // clear counter, keypress & erased flags 5002 flags &= 0x19u; 5003 } 5004 break; 5005 } 5006 num_actions++; 5007 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5008 break; 5009 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5010 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5011 // enter actions queued 5012 num_actions--; 5013 if (num_actions == 0u){ 5014 // clear counter, keypress & erased flags 5015 flags &= 0x19u; 5016 } 5017 break; 5018 } 5019 num_actions++; 5020 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5021 break; 5022 default: 5023 break; 5024 } 5025 setup->sm_keypress_notification = (num_actions << 5) | flags; 5026 sm_trigger_run(); 5027 } 5028 5029 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5030 static void sm_handle_random_result_oob(void * arg){ 5031 UNUSED(arg); 5032 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5033 sm_trigger_run(); 5034 } 5035 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5036 5037 static btstack_crypto_random_t sm_crypto_random_oob_request; 5038 5039 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5040 sm_sc_oob_callback = callback; 5041 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5042 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5043 return 0; 5044 } 5045 #endif 5046 5047 /** 5048 * @brief Get Identity Resolving state 5049 * @param con_handle 5050 * @return irk_lookup_state_t 5051 */ 5052 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5053 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5054 if (!sm_conn) return IRK_LOOKUP_IDLE; 5055 return sm_conn->sm_irk_lookup_state; 5056 } 5057 5058 /** 5059 * @brief Identify device in LE Device DB 5060 * @param handle 5061 * @return index from le_device_db or -1 if not found/identified 5062 */ 5063 int sm_le_device_index(hci_con_handle_t con_handle ){ 5064 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5065 if (!sm_conn) return -1; 5066 return sm_conn->sm_le_db_index; 5067 } 5068 5069 static int gap_random_address_type_requires_updates(void){ 5070 switch (gap_random_adress_type){ 5071 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5072 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5073 return 0; 5074 default: 5075 return 1; 5076 } 5077 } 5078 5079 static uint8_t own_address_type(void){ 5080 switch (gap_random_adress_type){ 5081 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5082 return BD_ADDR_TYPE_LE_PUBLIC; 5083 default: 5084 return BD_ADDR_TYPE_LE_RANDOM; 5085 } 5086 } 5087 5088 // GAP LE API 5089 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5090 gap_random_address_update_stop(); 5091 gap_random_adress_type = random_address_type; 5092 hci_le_set_own_address_type(own_address_type()); 5093 if (!gap_random_address_type_requires_updates()) return; 5094 gap_random_address_update_start(); 5095 gap_random_address_trigger(); 5096 } 5097 5098 gap_random_address_type_t gap_random_address_get_mode(void){ 5099 return gap_random_adress_type; 5100 } 5101 5102 void gap_random_address_set_update_period(int period_ms){ 5103 gap_random_adress_update_period = period_ms; 5104 if (!gap_random_address_type_requires_updates()) return; 5105 gap_random_address_update_stop(); 5106 gap_random_address_update_start(); 5107 } 5108 5109 void gap_random_address_set(const bd_addr_t addr){ 5110 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5111 (void)memcpy(sm_random_address, addr, 6); 5112 hci_le_random_address_set(addr); 5113 } 5114 5115 #ifdef ENABLE_LE_PERIPHERAL 5116 /* 5117 * @brief Set Advertisement Paramters 5118 * @param adv_int_min 5119 * @param adv_int_max 5120 * @param adv_type 5121 * @param direct_address_type 5122 * @param direct_address 5123 * @param channel_map 5124 * @param filter_policy 5125 * 5126 * @note own_address_type is used from gap_random_address_set_mode 5127 */ 5128 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5129 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5130 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5131 direct_address_typ, direct_address, channel_map, filter_policy); 5132 } 5133 #endif 5134 5135 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5136 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5137 // wrong connection 5138 if (!sm_conn) return 0; 5139 // already encrypted 5140 if (sm_conn->sm_connection_encrypted) return 0; 5141 // irk status? 5142 switch(sm_conn->sm_irk_lookup_state){ 5143 case IRK_LOOKUP_FAILED: 5144 // done, cannot setup encryption 5145 return 0; 5146 case IRK_LOOKUP_SUCCEEDED: 5147 break; 5148 default: 5149 // IR Lookup pending 5150 return 1; 5151 } 5152 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5153 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5154 if (sm_conn->sm_role){ 5155 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5156 } else { 5157 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5158 } 5159 } 5160 5161 void sm_set_secure_connections_only_mode(bool enable){ 5162 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5163 sm_sc_only_mode = enable; 5164 #else 5165 // SC Only mode not possible without support for SC 5166 btstack_assert(enable == false); 5167 #endif 5168 } 5169 5170 const uint8_t * gap_get_persistent_irk(void){ 5171 return sm_persistent_irk; 5172 } 5173 5174 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5175 uint16_t i; 5176 for (i=0; i < le_device_db_max_count(); i++){ 5177 bd_addr_t entry_address; 5178 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5179 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5180 // skip unused entries 5181 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5182 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5183 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 5184 hci_remove_le_device_db_entry_from_resolving_list(i); 5185 #endif 5186 le_device_db_remove(i); 5187 break; 5188 } 5189 } 5190 } 5191