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 uint32_t sm_fixed_passkey_in_display_role; 198 static bool sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_PERIPHERAL 201 static uint8_t sm_slave_request_security; 202 #endif 203 204 #ifdef ENABLE_LE_SECURE_CONNECTIONS 205 static bool sm_sc_only_mode; 206 static uint8_t sm_sc_oob_random[16]; 207 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 208 static sm_sc_oob_state_t sm_sc_oob_state; 209 #endif 210 211 212 static bool sm_persistent_keys_random_active; 213 static const btstack_tlv_t * sm_tlv_impl; 214 static void * sm_tlv_context; 215 216 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 217 static sm_key_t sm_persistent_er; 218 static sm_key_t sm_persistent_ir; 219 220 // derived from sm_persistent_ir 221 static sm_key_t sm_persistent_dhk; 222 static sm_key_t sm_persistent_irk; 223 static derived_key_generation_t dkg_state; 224 225 // derived from sm_persistent_er 226 // .. 227 228 // random address update 229 static random_address_update_t rau_state; 230 static bd_addr_t sm_random_address; 231 232 #ifdef USE_CMAC_ENGINE 233 // CMAC Calculation: General 234 static btstack_crypto_aes128_cmac_t sm_cmac_request; 235 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 236 static uint8_t sm_cmac_active; 237 static uint8_t sm_cmac_hash[16]; 238 #endif 239 240 // CMAC for ATT Signed Writes 241 #ifdef ENABLE_LE_SIGNED_WRITE 242 static uint16_t sm_cmac_signed_write_message_len; 243 static uint8_t sm_cmac_signed_write_header[3]; 244 static const uint8_t * sm_cmac_signed_write_message; 245 static uint8_t sm_cmac_signed_write_sign_counter[4]; 246 #endif 247 248 // CMAC for Secure Connection functions 249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 250 static sm_connection_t * sm_cmac_connection; 251 static uint8_t sm_cmac_sc_buffer[80]; 252 #endif 253 254 // resolvable private address lookup / CSRK calculation 255 static int sm_address_resolution_test; 256 static int sm_address_resolution_ah_calculation_active; 257 static uint8_t sm_address_resolution_addr_type; 258 static bd_addr_t sm_address_resolution_address; 259 static void * sm_address_resolution_context; 260 static address_resolution_mode_t sm_address_resolution_mode; 261 static btstack_linked_list_t sm_address_resolution_general_queue; 262 263 // aes128 crypto engine. 264 static sm_aes128_state_t sm_aes128_state; 265 266 // crypto 267 static btstack_crypto_random_t sm_crypto_random_request; 268 static btstack_crypto_aes128_t sm_crypto_aes128_request; 269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 270 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 271 #endif 272 273 // temp storage for random data 274 static uint8_t sm_random_data[8]; 275 static uint8_t sm_aes128_key[16]; 276 static uint8_t sm_aes128_plaintext[16]; 277 static uint8_t sm_aes128_ciphertext[16]; 278 279 // to receive hci events 280 static btstack_packet_callback_registration_t hci_event_callback_registration; 281 282 /* to dispatch sm event */ 283 static btstack_linked_list_t sm_event_handlers; 284 285 /* to schedule calls to sm_run */ 286 static btstack_timer_source_t sm_run_timer; 287 288 // LE Secure Connections 289 #ifdef ENABLE_LE_SECURE_CONNECTIONS 290 static ec_key_generation_state_t ec_key_generation_state; 291 static uint8_t ec_q[64]; 292 #endif 293 294 // 295 // Volume 3, Part H, Chapter 24 296 // "Security shall be initiated by the Security Manager in the device in the master role. 297 // The device in the slave role shall be the responding device." 298 // -> master := initiator, slave := responder 299 // 300 301 // data needed for security setup 302 typedef struct sm_setup_context { 303 304 btstack_timer_source_t sm_timeout; 305 306 // user response, (Phase 1 and/or 2) 307 uint8_t sm_user_response; 308 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 309 310 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 311 uint8_t sm_key_distribution_send_set; 312 uint8_t sm_key_distribution_sent_set; 313 uint8_t sm_key_distribution_expected_set; 314 uint8_t sm_key_distribution_received_set; 315 316 // Phase 2 (Pairing over SMP) 317 stk_generation_method_t sm_stk_generation_method; 318 sm_key_t sm_tk; 319 uint8_t sm_have_oob_data; 320 uint8_t sm_use_secure_connections; 321 322 sm_key_t sm_c1_t3_value; // c1 calculation 323 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 324 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 325 sm_key_t sm_local_random; 326 sm_key_t sm_local_confirm; 327 sm_key_t sm_peer_random; 328 sm_key_t sm_peer_confirm; 329 uint8_t sm_m_addr_type; // address and type can be removed 330 uint8_t sm_s_addr_type; // '' 331 bd_addr_t sm_m_address; // '' 332 bd_addr_t sm_s_address; // '' 333 sm_key_t sm_ltk; 334 335 uint8_t sm_state_vars; 336 #ifdef ENABLE_LE_SECURE_CONNECTIONS 337 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 338 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 339 sm_key_t sm_local_nonce; // might be combined with sm_local_random 340 uint8_t sm_dhkey[32]; 341 sm_key_t sm_peer_dhkey_check; 342 sm_key_t sm_local_dhkey_check; 343 sm_key_t sm_ra; 344 sm_key_t sm_rb; 345 sm_key_t sm_t; // used for f5 and h6 346 sm_key_t sm_mackey; 347 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 348 #endif 349 350 // Phase 3 351 352 // key distribution, we generate 353 uint16_t sm_local_y; 354 uint16_t sm_local_div; 355 uint16_t sm_local_ediv; 356 uint8_t sm_local_rand[8]; 357 sm_key_t sm_local_ltk; 358 sm_key_t sm_local_csrk; 359 sm_key_t sm_local_irk; 360 // sm_local_address/addr_type not needed 361 362 // key distribution, received from peer 363 uint16_t sm_peer_y; 364 uint16_t sm_peer_div; 365 uint16_t sm_peer_ediv; 366 uint8_t sm_peer_rand[8]; 367 sm_key_t sm_peer_ltk; 368 sm_key_t sm_peer_irk; 369 sm_key_t sm_peer_csrk; 370 uint8_t sm_peer_addr_type; 371 bd_addr_t sm_peer_address; 372 #ifdef ENABLE_LE_SIGNED_WRITE 373 int sm_le_device_index; 374 #endif 375 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 376 link_key_t sm_link_key; 377 link_key_type_t sm_link_key_type; 378 #endif 379 } sm_setup_context_t; 380 381 // 382 static sm_setup_context_t the_setup; 383 static sm_setup_context_t * setup = &the_setup; 384 385 // active connection - the one for which the_setup is used for 386 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 387 388 // @return 1 if oob data is available 389 // stores oob data in provided 16 byte buffer if not null 390 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 391 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); 392 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 393 394 static void sm_run(void); 395 static void sm_done_for_handle(hci_con_handle_t con_handle); 396 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 397 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 398 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 399 #endif 400 static inline int sm_calc_actual_encryption_key_size(int other); 401 static int sm_validate_stk_generation_method(void); 402 static void sm_handle_encryption_result_address_resolution(void *arg); 403 static void sm_handle_encryption_result_dkg_dhk(void *arg); 404 static void sm_handle_encryption_result_dkg_irk(void *arg); 405 static void sm_handle_encryption_result_enc_a(void *arg); 406 static void sm_handle_encryption_result_enc_b(void *arg); 407 static void sm_handle_encryption_result_enc_c(void *arg); 408 static void sm_handle_encryption_result_enc_csrk(void *arg); 409 static void sm_handle_encryption_result_enc_d(void * arg); 410 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 411 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 412 #ifdef ENABLE_LE_PERIPHERAL 413 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 414 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 415 #endif 416 static void sm_handle_encryption_result_enc_stk(void *arg); 417 static void sm_handle_encryption_result_rau(void *arg); 418 static void sm_handle_random_result_ph2_tk(void * arg); 419 static void sm_handle_random_result_rau(void * arg); 420 #ifdef ENABLE_LE_SECURE_CONNECTIONS 421 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)); 422 static void sm_ec_generate_new_key(void); 423 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 424 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 425 static int sm_passkey_entry(stk_generation_method_t method); 426 #endif 427 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 428 429 static void log_info_hex16(const char * name, uint16_t value){ 430 log_info("%-6s 0x%04x", name, value); 431 } 432 433 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 434 // return packet[0]; 435 // } 436 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 437 return packet[1]; 438 } 439 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 440 return packet[2]; 441 } 442 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 443 return packet[3]; 444 } 445 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 446 return packet[4]; 447 } 448 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 449 return packet[5]; 450 } 451 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 452 return packet[6]; 453 } 454 455 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 456 packet[0] = code; 457 } 458 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 459 packet[1] = io_capability; 460 } 461 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 462 packet[2] = oob_data_flag; 463 } 464 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 465 packet[3] = auth_req; 466 } 467 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 468 packet[4] = max_encryption_key_size; 469 } 470 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 471 packet[5] = initiator_key_distribution; 472 } 473 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 474 packet[6] = responder_key_distribution; 475 } 476 477 // @return 1 if all bytes are 0 478 static bool sm_is_null(uint8_t * data, int size){ 479 int i; 480 for (i=0; i < size ; i++){ 481 if (data[i] != 0) { 482 return false; 483 } 484 } 485 return true; 486 } 487 488 static bool sm_is_null_random(uint8_t random[8]){ 489 return sm_is_null(random, 8); 490 } 491 492 static bool sm_is_null_key(uint8_t * key){ 493 return sm_is_null(key, 16); 494 } 495 496 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 497 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 498 UNUSED(ts); 499 sm_run(); 500 } 501 static void sm_trigger_run(void){ 502 if (!sm_initialized) return; 503 (void)btstack_run_loop_remove_timer(&sm_run_timer); 504 btstack_run_loop_set_timer(&sm_run_timer, 0); 505 btstack_run_loop_add_timer(&sm_run_timer); 506 } 507 508 // Key utils 509 static void sm_reset_tk(void){ 510 int i; 511 for (i=0;i<16;i++){ 512 setup->sm_tk[i] = 0; 513 } 514 } 515 516 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 517 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 518 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 519 int i; 520 for (i = max_encryption_size ; i < 16 ; i++){ 521 key[15-i] = 0; 522 } 523 } 524 525 // ER / IR checks 526 static void sm_er_ir_set_default(void){ 527 int i; 528 for (i=0;i<16;i++){ 529 sm_persistent_er[i] = 0x30 + i; 530 sm_persistent_ir[i] = 0x90 + i; 531 } 532 } 533 534 static int sm_er_is_default(void){ 535 int i; 536 for (i=0;i<16;i++){ 537 if (sm_persistent_er[i] != (0x30+i)) return 0; 538 } 539 return 1; 540 } 541 542 static int sm_ir_is_default(void){ 543 int i; 544 for (i=0;i<16;i++){ 545 if (sm_persistent_ir[i] != (0x90+i)) return 0; 546 } 547 return 1; 548 } 549 550 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 551 UNUSED(channel); 552 553 // log event 554 hci_dump_packet(packet_type, 1, packet, size); 555 // dispatch to all event handlers 556 btstack_linked_list_iterator_t it; 557 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 558 while (btstack_linked_list_iterator_has_next(&it)){ 559 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 560 entry->callback(packet_type, 0, packet, size); 561 } 562 } 563 564 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){ 565 event[0] = type; 566 event[1] = event_size - 2; 567 little_endian_store_16(event, 2, con_handle); 568 event[4] = addr_type; 569 reverse_bd_addr(address, &event[5]); 570 } 571 572 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 573 uint8_t event[11]; 574 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 575 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 576 } 577 578 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){ 579 // fetch addr and addr type from db, only called for valid entries 580 bd_addr_t identity_address; 581 int identity_address_type; 582 le_device_db_info(index, &identity_address_type, identity_address, NULL); 583 584 uint8_t event[20]; 585 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 586 event[11] = identity_address_type; 587 reverse_bd_addr(identity_address, &event[12]); 588 little_endian_store_16(event, 18, index); 589 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 590 } 591 592 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){ 593 uint8_t event[12]; 594 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 595 event[11] = status; 596 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 597 } 598 599 600 static void sm_reencryption_started(sm_connection_t * sm_conn){ 601 602 if (sm_conn->sm_reencryption_active) return; 603 604 sm_conn->sm_reencryption_active = true; 605 606 int identity_addr_type; 607 bd_addr_t identity_addr; 608 if (sm_conn->sm_le_db_index >= 0){ 609 // fetch addr and addr type from db, only called for valid entries 610 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 611 } else { 612 // for legacy pairing with LTK re-construction, use current peer addr 613 identity_addr_type = sm_conn->sm_peer_addr_type; 614 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 615 } 616 617 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 618 } 619 620 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 621 622 if (!sm_conn->sm_reencryption_active) return; 623 624 sm_conn->sm_reencryption_active = false; 625 626 int identity_addr_type; 627 bd_addr_t identity_addr; 628 if (sm_conn->sm_le_db_index >= 0){ 629 // fetch addr and addr type from db, only called for valid entries 630 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 631 } else { 632 // for legacy pairing with LTK re-construction, use current peer addr 633 identity_addr_type = sm_conn->sm_peer_addr_type; 634 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 635 } 636 637 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 638 } 639 640 static void sm_pairing_started(sm_connection_t * sm_conn){ 641 642 if (sm_conn->sm_pairing_active) return; 643 644 sm_conn->sm_pairing_active = true; 645 646 uint8_t event[11]; 647 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 648 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 649 } 650 651 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 652 653 if (!sm_conn->sm_pairing_active) return; 654 655 sm_conn->sm_pairing_active = false; 656 657 uint8_t event[13]; 658 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 659 event[11] = status; 660 event[12] = reason; 661 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 662 } 663 664 // SMP Timeout implementation 665 666 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 667 // the Security Manager Timer shall be reset and started. 668 // 669 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 670 // 671 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 672 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 673 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 674 // established. 675 676 static void sm_timeout_handler(btstack_timer_source_t * timer){ 677 log_info("SM timeout"); 678 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 679 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 680 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 681 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 682 sm_done_for_handle(sm_conn->sm_handle); 683 684 // trigger handling of next ready connection 685 sm_run(); 686 } 687 static void sm_timeout_start(sm_connection_t * sm_conn){ 688 btstack_run_loop_remove_timer(&setup->sm_timeout); 689 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 690 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 691 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 692 btstack_run_loop_add_timer(&setup->sm_timeout); 693 } 694 static void sm_timeout_stop(void){ 695 btstack_run_loop_remove_timer(&setup->sm_timeout); 696 } 697 static void sm_timeout_reset(sm_connection_t * sm_conn){ 698 sm_timeout_stop(); 699 sm_timeout_start(sm_conn); 700 } 701 702 // end of sm timeout 703 704 // GAP Random Address updates 705 static gap_random_address_type_t gap_random_adress_type; 706 static btstack_timer_source_t gap_random_address_update_timer; 707 static uint32_t gap_random_adress_update_period; 708 709 static void gap_random_address_trigger(void){ 710 log_info("gap_random_address_trigger, state %u", rau_state); 711 if (rau_state != RAU_IDLE) return; 712 rau_state = RAU_GET_RANDOM; 713 sm_trigger_run(); 714 } 715 716 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 717 UNUSED(timer); 718 719 log_info("GAP Random Address Update due"); 720 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 721 btstack_run_loop_add_timer(&gap_random_address_update_timer); 722 gap_random_address_trigger(); 723 } 724 725 static void gap_random_address_update_start(void){ 726 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 727 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 728 btstack_run_loop_add_timer(&gap_random_address_update_timer); 729 } 730 731 static void gap_random_address_update_stop(void){ 732 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 733 } 734 735 // ah(k,r) helper 736 // r = padding || r 737 // r - 24 bit value 738 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 739 // r'= padding || r 740 memset(r_prime, 0, 16); 741 (void)memcpy(&r_prime[13], r, 3); 742 } 743 744 // d1 helper 745 // d' = padding || r || d 746 // d,r - 16 bit values 747 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 748 // d'= padding || r || d 749 memset(d1_prime, 0, 16); 750 big_endian_store_16(d1_prime, 12, r); 751 big_endian_store_16(d1_prime, 14, d); 752 } 753 754 // calculate arguments for first AES128 operation in C1 function 755 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){ 756 757 // p1 = pres || preq || rat’ || iat’ 758 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 759 // cant octet of pres becomes the most significant octet of p1. 760 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 761 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 762 // p1 is 0x05000800000302070710000001010001." 763 764 sm_key_t p1; 765 reverse_56(pres, &p1[0]); 766 reverse_56(preq, &p1[7]); 767 p1[14] = rat; 768 p1[15] = iat; 769 log_info_key("p1", p1); 770 log_info_key("r", r); 771 772 // t1 = r xor p1 773 int i; 774 for (i=0;i<16;i++){ 775 t1[i] = r[i] ^ p1[i]; 776 } 777 log_info_key("t1", t1); 778 } 779 780 // calculate arguments for second AES128 operation in C1 function 781 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 782 // p2 = padding || ia || ra 783 // "The least significant octet of ra becomes the least significant octet of p2 and 784 // the most significant octet of padding becomes the most significant octet of p2. 785 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 786 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 787 788 sm_key_t p2; 789 memset(p2, 0, 16); 790 (void)memcpy(&p2[4], ia, 6); 791 (void)memcpy(&p2[10], ra, 6); 792 log_info_key("p2", p2); 793 794 // c1 = e(k, t2_xor_p2) 795 int i; 796 for (i=0;i<16;i++){ 797 t3[i] = t2[i] ^ p2[i]; 798 } 799 log_info_key("t3", t3); 800 } 801 802 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 803 log_info_key("r1", r1); 804 log_info_key("r2", r2); 805 (void)memcpy(&r_prime[8], &r2[8], 8); 806 (void)memcpy(&r_prime[0], &r1[8], 8); 807 } 808 809 810 // decide on stk generation based on 811 // - pairing request 812 // - io capabilities 813 // - OOB data availability 814 static void sm_setup_tk(void){ 815 816 // horizontal: initiator capabilities 817 // vertial: responder capabilities 818 static const stk_generation_method_t stk_generation_method [5] [5] = { 819 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 820 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 821 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 822 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 823 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 824 }; 825 826 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 827 #ifdef ENABLE_LE_SECURE_CONNECTIONS 828 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 829 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 830 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 831 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 832 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 833 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 834 }; 835 #endif 836 837 // default: just works 838 setup->sm_stk_generation_method = JUST_WORKS; 839 840 #ifdef ENABLE_LE_SECURE_CONNECTIONS 841 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 842 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 843 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 844 #else 845 setup->sm_use_secure_connections = 0; 846 #endif 847 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 848 849 850 // decide if OOB will be used based on SC vs. Legacy and oob flags 851 bool use_oob; 852 if (setup->sm_use_secure_connections){ 853 // In LE Secure Connections pairing, the out of band method is used if at least 854 // one device has the peer device's out of band authentication data available. 855 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; 856 } else { 857 // In LE legacy pairing, the out of band method is used if both the devices have 858 // the other device's out of band authentication data available. 859 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; 860 } 861 if (use_oob){ 862 log_info("SM: have OOB data"); 863 log_info_key("OOB", setup->sm_tk); 864 setup->sm_stk_generation_method = OOB; 865 return; 866 } 867 868 // If both devices have not set the MITM option in the Authentication Requirements 869 // Flags, then the IO capabilities shall be ignored and the Just Works association 870 // model shall be used. 871 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 872 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 873 log_info("SM: MITM not required by both -> JUST WORKS"); 874 return; 875 } 876 877 // Reset TK as it has been setup in sm_init_setup 878 sm_reset_tk(); 879 880 // Also use just works if unknown io capabilites 881 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)){ 882 return; 883 } 884 885 // Otherwise the IO capabilities of the devices shall be used to determine the 886 // pairing method as defined in Table 2.4. 887 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 888 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 889 890 #ifdef ENABLE_LE_SECURE_CONNECTIONS 891 // table not define by default 892 if (setup->sm_use_secure_connections){ 893 generation_method = stk_generation_method_with_secure_connection; 894 } 895 #endif 896 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)]; 897 898 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 899 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); 900 } 901 902 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 903 int flags = 0; 904 if (key_set & SM_KEYDIST_ENC_KEY){ 905 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 906 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 907 } 908 if (key_set & SM_KEYDIST_ID_KEY){ 909 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 910 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 911 } 912 if (key_set & SM_KEYDIST_SIGN){ 913 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 914 } 915 return flags; 916 } 917 918 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 919 setup->sm_key_distribution_received_set = 0; 920 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 921 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 922 setup->sm_key_distribution_sent_set = 0; 923 #ifdef ENABLE_LE_SIGNED_WRITE 924 setup->sm_le_device_index = -1; 925 #endif 926 } 927 928 // CSRK Key Lookup 929 930 931 static int sm_address_resolution_idle(void){ 932 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 933 } 934 935 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){ 936 (void)memcpy(sm_address_resolution_address, addr, 6); 937 sm_address_resolution_addr_type = addr_type; 938 sm_address_resolution_test = 0; 939 sm_address_resolution_mode = mode; 940 sm_address_resolution_context = context; 941 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 942 } 943 944 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 945 // check if already in list 946 btstack_linked_list_iterator_t it; 947 sm_lookup_entry_t * entry; 948 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 949 while(btstack_linked_list_iterator_has_next(&it)){ 950 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 951 if (entry->address_type != address_type) continue; 952 if (memcmp(entry->address, address, 6)) continue; 953 // already in list 954 return BTSTACK_BUSY; 955 } 956 entry = btstack_memory_sm_lookup_entry_get(); 957 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 958 entry->address_type = (bd_addr_type_t) address_type; 959 (void)memcpy(entry->address, address, 6); 960 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 961 sm_trigger_run(); 962 return 0; 963 } 964 965 // CMAC calculation using AES Engineq 966 #ifdef USE_CMAC_ENGINE 967 968 static void sm_cmac_done_trampoline(void * arg){ 969 UNUSED(arg); 970 sm_cmac_active = 0; 971 (*sm_cmac_done_callback)(sm_cmac_hash); 972 sm_trigger_run(); 973 } 974 975 int sm_cmac_ready(void){ 976 return sm_cmac_active == 0u; 977 } 978 #endif 979 980 #ifdef ENABLE_LE_SECURE_CONNECTIONS 981 // generic cmac calculation 982 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)){ 983 sm_cmac_active = 1; 984 sm_cmac_done_callback = done_callback; 985 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 986 } 987 #endif 988 989 // cmac for ATT Message signing 990 #ifdef ENABLE_LE_SIGNED_WRITE 991 992 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)){ 993 sm_cmac_active = 1; 994 sm_cmac_done_callback = done_callback; 995 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 996 } 997 998 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 999 if (offset >= sm_cmac_signed_write_message_len) { 1000 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1001 return 0; 1002 } 1003 1004 offset = sm_cmac_signed_write_message_len - 1 - offset; 1005 1006 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1007 if (offset < 3){ 1008 return sm_cmac_signed_write_header[offset]; 1009 } 1010 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1011 if (offset < actual_message_len_incl_header){ 1012 return sm_cmac_signed_write_message[offset - 3]; 1013 } 1014 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1015 } 1016 1017 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)){ 1018 // ATT Message Signing 1019 sm_cmac_signed_write_header[0] = opcode; 1020 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1021 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1022 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1023 sm_cmac_signed_write_message = message; 1024 sm_cmac_signed_write_message_len = total_message_len; 1025 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1026 } 1027 #endif 1028 1029 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1030 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1031 uint8_t event[12]; 1032 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1033 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1034 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1035 } 1036 1037 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn){ 1038 uint8_t event[16]; 1039 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1040 sm_setup_event_base(event, sizeof(event), SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, 1041 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1042 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1043 little_endian_store_32(event, 12, passkey); 1044 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1045 } 1046 1047 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1048 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1049 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1050 sm_conn->sm_pairing_active = true; 1051 switch (setup->sm_stk_generation_method){ 1052 case PK_RESP_INPUT: 1053 if (IS_RESPONDER(sm_conn->sm_role)){ 1054 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1055 } else { 1056 sm_trigger_user_response_passkey(sm_conn); 1057 } 1058 break; 1059 case PK_INIT_INPUT: 1060 if (IS_RESPONDER(sm_conn->sm_role)){ 1061 sm_trigger_user_response_passkey(sm_conn); 1062 } else { 1063 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1064 } 1065 break; 1066 case PK_BOTH_INPUT: 1067 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1068 break; 1069 case NUMERIC_COMPARISON: 1070 sm_trigger_user_response_basic(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1071 break; 1072 case JUST_WORKS: 1073 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1074 break; 1075 case OOB: 1076 // client already provided OOB data, let's skip notification. 1077 break; 1078 default: 1079 btstack_assert(false); 1080 break; 1081 } 1082 } 1083 1084 static bool sm_key_distribution_all_received(void) { 1085 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, setup->sm_key_distribution_expected_set); 1086 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1087 } 1088 1089 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1090 if (sm_active_connection_handle == con_handle){ 1091 sm_timeout_stop(); 1092 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1093 log_info("sm: connection 0x%x released setup context", con_handle); 1094 1095 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1096 // generate new ec key after each pairing (that used it) 1097 if (setup->sm_use_secure_connections){ 1098 sm_ec_generate_new_key(); 1099 } 1100 #endif 1101 } 1102 } 1103 1104 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1105 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1106 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1107 sm_done_for_handle(connection->sm_handle); 1108 } 1109 1110 static int sm_key_distribution_flags_for_auth_req(void){ 1111 1112 int flags = SM_KEYDIST_ID_KEY; 1113 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1114 // encryption and signing information only if bonding requested 1115 flags |= SM_KEYDIST_ENC_KEY; 1116 #ifdef ENABLE_LE_SIGNED_WRITE 1117 flags |= SM_KEYDIST_SIGN; 1118 #endif 1119 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1120 // LinkKey for CTKD requires SC 1121 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1122 flags |= SM_KEYDIST_LINK_KEY; 1123 } 1124 #endif 1125 } 1126 return flags; 1127 } 1128 1129 static void sm_reset_setup(void){ 1130 // fill in sm setup 1131 setup->sm_state_vars = 0; 1132 setup->sm_keypress_notification = 0; 1133 setup->sm_have_oob_data = 0; 1134 sm_reset_tk(); 1135 } 1136 1137 static void sm_init_setup(sm_connection_t * sm_conn){ 1138 // fill in sm setup 1139 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1140 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1141 1142 // query client for Legacy Pairing OOB data 1143 if (sm_get_oob_data != NULL) { 1144 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1145 } 1146 1147 // if available and SC supported, also ask for SC OOB Data 1148 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1149 memset(setup->sm_ra, 0, 16); 1150 memset(setup->sm_rb, 0, 16); 1151 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1152 if (sm_get_sc_oob_data != NULL){ 1153 if (IS_RESPONDER(sm_conn->sm_role)){ 1154 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1155 sm_conn->sm_peer_addr_type, 1156 sm_conn->sm_peer_address, 1157 setup->sm_peer_confirm, 1158 setup->sm_ra); 1159 } else { 1160 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1161 sm_conn->sm_peer_addr_type, 1162 sm_conn->sm_peer_address, 1163 setup->sm_peer_confirm, 1164 setup->sm_rb); 1165 } 1166 } else { 1167 setup->sm_have_oob_data = 0; 1168 } 1169 } 1170 #endif 1171 1172 sm_pairing_packet_t * local_packet; 1173 if (IS_RESPONDER(sm_conn->sm_role)){ 1174 // slave 1175 local_packet = &setup->sm_s_pres; 1176 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1177 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1178 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1179 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1180 } else { 1181 // master 1182 local_packet = &setup->sm_m_preq; 1183 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1184 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1185 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1186 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1187 1188 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1189 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1190 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1191 } 1192 1193 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1194 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1195 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1196 // enable SC for SC only mode 1197 if (sm_sc_only_mode){ 1198 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1199 max_encryption_key_size = 16; 1200 } 1201 #endif 1202 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1203 // set CT2 if SC + Bonding + CTKD 1204 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1205 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1206 auth_req |= SM_AUTHREQ_CT2; 1207 } 1208 #endif 1209 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1210 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1211 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1212 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1213 } 1214 1215 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1216 1217 sm_pairing_packet_t * remote_packet; 1218 uint8_t keys_to_send; 1219 uint8_t keys_to_receive; 1220 if (IS_RESPONDER(sm_conn->sm_role)){ 1221 // slave / responder 1222 remote_packet = &setup->sm_m_preq; 1223 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1224 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1225 } else { 1226 // master / initiator 1227 remote_packet = &setup->sm_s_pres; 1228 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1229 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1230 } 1231 1232 // check key size 1233 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1234 // SC Only mandates 128 bit key size 1235 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1236 return SM_REASON_ENCRYPTION_KEY_SIZE; 1237 } 1238 #endif 1239 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1240 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1241 1242 // decide on STK generation method / SC 1243 sm_setup_tk(); 1244 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1245 1246 // check if STK generation method is acceptable by client 1247 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1248 1249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1250 // Check LE SC Only mode 1251 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1252 log_info("SC Only mode active but SC not possible"); 1253 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1254 } 1255 1256 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1257 if (setup->sm_use_secure_connections){ 1258 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1259 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1260 } 1261 #endif 1262 1263 // identical to responder 1264 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1265 1266 // JUST WORKS doens't provide authentication 1267 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1268 1269 return 0; 1270 } 1271 1272 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1273 1274 // cache and reset context 1275 int matched_device_id = sm_address_resolution_test; 1276 address_resolution_mode_t mode = sm_address_resolution_mode; 1277 void * context = sm_address_resolution_context; 1278 1279 // reset context 1280 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1281 sm_address_resolution_context = NULL; 1282 sm_address_resolution_test = -1; 1283 hci_con_handle_t con_handle = 0; 1284 1285 sm_connection_t * sm_connection; 1286 sm_key_t ltk; 1287 bool have_ltk; 1288 #ifdef ENABLE_LE_CENTRAL 1289 bool trigger_pairing; 1290 #endif 1291 switch (mode){ 1292 case ADDRESS_RESOLUTION_GENERAL: 1293 break; 1294 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1295 sm_connection = (sm_connection_t *) context; 1296 con_handle = sm_connection->sm_handle; 1297 1298 // have ltk -> start encryption / send security request 1299 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1300 // "When a bond has been created between two devices, any reconnection should result in the local device 1301 // enabling or requesting encryption with the remote device before initiating any service request." 1302 1303 switch (event){ 1304 case ADDRESS_RESOLUTION_SUCCEEDED: 1305 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1306 sm_connection->sm_le_db_index = matched_device_id; 1307 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1308 1309 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1310 have_ltk = !sm_is_null_key(ltk); 1311 1312 if (sm_connection->sm_role) { 1313 #ifdef ENABLE_LE_PERIPHERAL 1314 // IRK required before, continue 1315 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1316 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1317 break; 1318 } 1319 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1320 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1321 break; 1322 } 1323 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1324 sm_connection->sm_pairing_requested = 0; 1325 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1326 // trigger security request for Proactive Authentication if LTK available 1327 trigger_security_request = trigger_security_request || have_ltk; 1328 #endif 1329 1330 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1331 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1332 1333 if (trigger_security_request){ 1334 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1335 if (have_ltk){ 1336 sm_reencryption_started(sm_connection); 1337 } else { 1338 sm_pairing_started(sm_connection); 1339 } 1340 sm_trigger_run(); 1341 } 1342 #endif 1343 } else { 1344 1345 #ifdef ENABLE_LE_CENTRAL 1346 // check if pairing already requested and reset requests 1347 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1348 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1349 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1350 sm_connection->sm_security_request_received = 0; 1351 sm_connection->sm_pairing_requested = 0; 1352 bool trigger_reencryption = false; 1353 1354 if (have_ltk){ 1355 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1356 trigger_reencryption = true; 1357 #else 1358 if (trigger_pairing){ 1359 trigger_reencryption = true; 1360 } else { 1361 log_info("central: defer enabling encryption for bonded device"); 1362 } 1363 #endif 1364 } 1365 1366 if (trigger_reencryption){ 1367 log_info("central: enable encryption for bonded device"); 1368 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1369 break; 1370 } 1371 1372 // pairing_request -> send pairing request 1373 if (trigger_pairing){ 1374 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1375 break; 1376 } 1377 #endif 1378 } 1379 break; 1380 case ADDRESS_RESOLUTION_FAILED: 1381 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1382 if (sm_connection->sm_role) { 1383 #ifdef ENABLE_LE_PERIPHERAL 1384 // LTK request received before, IRK required -> negative LTK reply 1385 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1386 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1387 } 1388 // send security request if requested 1389 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1390 sm_connection->sm_pairing_requested = 0; 1391 if (trigger_security_request){ 1392 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1393 sm_pairing_started(sm_connection); 1394 } 1395 break; 1396 #endif 1397 } 1398 #ifdef ENABLE_LE_CENTRAL 1399 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1400 sm_connection->sm_security_request_received = 0; 1401 sm_connection->sm_pairing_requested = 0; 1402 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1403 #endif 1404 break; 1405 1406 default: 1407 btstack_assert(false); 1408 break; 1409 } 1410 break; 1411 default: 1412 break; 1413 } 1414 1415 switch (event){ 1416 case ADDRESS_RESOLUTION_SUCCEEDED: 1417 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1418 break; 1419 case ADDRESS_RESOLUTION_FAILED: 1420 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1421 break; 1422 default: 1423 btstack_assert(false); 1424 break; 1425 } 1426 } 1427 1428 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1429 int le_db_index = -1; 1430 1431 // lookup device based on IRK 1432 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1433 int i; 1434 for (i=0; i < le_device_db_max_count(); i++){ 1435 sm_key_t irk; 1436 bd_addr_t address; 1437 int address_type = BD_ADDR_TYPE_UNKNOWN; 1438 le_device_db_info(i, &address_type, address, irk); 1439 // skip unused entries 1440 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1441 // compare Identity Address 1442 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1443 // compare Identity Resolving Key 1444 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1445 1446 log_info("sm: device found for IRK, updating"); 1447 le_db_index = i; 1448 break; 1449 } 1450 } else { 1451 // assert IRK is set to zero 1452 memset(setup->sm_peer_irk, 0, 16); 1453 } 1454 1455 // if not found, lookup via public address if possible 1456 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1457 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1458 int i; 1459 for (i=0; i < le_device_db_max_count(); i++){ 1460 bd_addr_t address; 1461 int address_type = BD_ADDR_TYPE_UNKNOWN; 1462 le_device_db_info(i, &address_type, address, NULL); 1463 // skip unused entries 1464 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1465 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1466 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1467 log_info("sm: device found for public address, updating"); 1468 le_db_index = i; 1469 break; 1470 } 1471 } 1472 } 1473 1474 // if not found, add to db 1475 bool new_to_le_device_db = false; 1476 if (le_db_index < 0) { 1477 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1478 new_to_le_device_db = true; 1479 } 1480 1481 if (le_db_index >= 0){ 1482 1483 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1484 if (!new_to_le_device_db){ 1485 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1486 } 1487 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1488 #else 1489 UNUSED(new_to_le_device_db); 1490 #endif 1491 1492 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1493 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1494 sm_conn->sm_le_db_index = le_db_index; 1495 1496 #ifdef ENABLE_LE_SIGNED_WRITE 1497 // store local CSRK 1498 setup->sm_le_device_index = le_db_index; 1499 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1500 log_info("sm: store local CSRK"); 1501 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1502 le_device_db_local_counter_set(le_db_index, 0); 1503 } 1504 1505 // store remote CSRK 1506 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1507 log_info("sm: store remote CSRK"); 1508 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1509 le_device_db_remote_counter_set(le_db_index, 0); 1510 } 1511 #endif 1512 // store encryption information for secure connections: LTK generated by ECDH 1513 if (setup->sm_use_secure_connections){ 1514 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1515 uint8_t zero_rand[8]; 1516 memset(zero_rand, 0, 8); 1517 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1518 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1519 } 1520 1521 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1522 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1523 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1524 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1525 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1526 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1527 1528 } 1529 } 1530 } 1531 1532 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1533 1534 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1535 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1536 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1537 & SM_AUTHREQ_BONDING ) != 0u; 1538 1539 if (bonding_enabled){ 1540 sm_store_bonding_information(sm_conn); 1541 } else { 1542 log_info("Ignoring received keys, bonding not enabled"); 1543 } 1544 } 1545 1546 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1547 sm_conn->sm_pairing_failed_reason = reason; 1548 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1549 } 1550 1551 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1552 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1553 } 1554 1555 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1556 1557 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1558 static int sm_passkey_used(stk_generation_method_t method); 1559 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1560 1561 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1562 if (setup->sm_stk_generation_method == OOB){ 1563 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1564 } else { 1565 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); 1566 } 1567 } 1568 1569 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1570 if (IS_RESPONDER(sm_conn->sm_role)){ 1571 // Responder 1572 if (setup->sm_stk_generation_method == OOB){ 1573 // generate Nb 1574 log_info("Generate Nb"); 1575 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); 1576 } else { 1577 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1578 } 1579 } else { 1580 // Initiator role 1581 switch (setup->sm_stk_generation_method){ 1582 case JUST_WORKS: 1583 sm_sc_prepare_dhkey_check(sm_conn); 1584 break; 1585 1586 case NUMERIC_COMPARISON: 1587 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1588 break; 1589 case PK_INIT_INPUT: 1590 case PK_RESP_INPUT: 1591 case PK_BOTH_INPUT: 1592 if (setup->sm_passkey_bit < 20u) { 1593 sm_sc_start_calculating_local_confirm(sm_conn); 1594 } else { 1595 sm_sc_prepare_dhkey_check(sm_conn); 1596 } 1597 break; 1598 case OOB: 1599 sm_sc_prepare_dhkey_check(sm_conn); 1600 break; 1601 default: 1602 btstack_assert(false); 1603 break; 1604 } 1605 } 1606 } 1607 1608 static void sm_sc_cmac_done(uint8_t * hash){ 1609 log_info("sm_sc_cmac_done: "); 1610 log_info_hexdump(hash, 16); 1611 1612 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1613 sm_sc_oob_state = SM_SC_OOB_IDLE; 1614 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1615 return; 1616 } 1617 1618 sm_connection_t * sm_conn = sm_cmac_connection; 1619 sm_cmac_connection = NULL; 1620 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1621 link_key_type_t link_key_type; 1622 #endif 1623 1624 switch (sm_conn->sm_engine_state){ 1625 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1626 (void)memcpy(setup->sm_local_confirm, hash, 16); 1627 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1628 break; 1629 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1630 // check 1631 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1632 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1633 break; 1634 } 1635 sm_sc_state_after_receiving_random(sm_conn); 1636 break; 1637 case SM_SC_W4_CALCULATE_G2: { 1638 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1639 big_endian_store_32(setup->sm_tk, 12, vab); 1640 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1641 sm_trigger_user_response(sm_conn); 1642 break; 1643 } 1644 case SM_SC_W4_CALCULATE_F5_SALT: 1645 (void)memcpy(setup->sm_t, hash, 16); 1646 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1647 break; 1648 case SM_SC_W4_CALCULATE_F5_MACKEY: 1649 (void)memcpy(setup->sm_mackey, hash, 16); 1650 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1651 break; 1652 case SM_SC_W4_CALCULATE_F5_LTK: 1653 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1654 // Errata Service Release to the Bluetooth Specification: ESR09 1655 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1656 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1657 (void)memcpy(setup->sm_ltk, hash, 16); 1658 (void)memcpy(setup->sm_local_ltk, hash, 16); 1659 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1660 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1661 break; 1662 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1663 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1664 if (IS_RESPONDER(sm_conn->sm_role)){ 1665 // responder 1666 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1667 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1668 } else { 1669 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1670 } 1671 } else { 1672 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1673 } 1674 break; 1675 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1676 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1677 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1678 break; 1679 } 1680 if (IS_RESPONDER(sm_conn->sm_role)){ 1681 // responder 1682 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1683 } else { 1684 // initiator 1685 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1686 } 1687 break; 1688 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1689 case SM_SC_W4_CALCULATE_ILK: 1690 (void)memcpy(setup->sm_t, hash, 16); 1691 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1692 break; 1693 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1694 reverse_128(hash, setup->sm_t); 1695 link_key_type = sm_conn->sm_connection_authenticated ? 1696 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1697 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1698 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1699 if (IS_RESPONDER(sm_conn->sm_role)){ 1700 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1701 } else { 1702 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1703 } 1704 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1705 sm_done_for_handle(sm_conn->sm_handle); 1706 break; 1707 case SM_BR_EDR_W4_CALCULATE_ILK: 1708 (void)memcpy(setup->sm_t, hash, 16); 1709 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1710 break; 1711 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1712 log_info("Derived LE LTK from BR/EDR Link Key"); 1713 log_info_key("Link Key", hash); 1714 (void)memcpy(setup->sm_ltk, hash, 16); 1715 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1716 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1717 sm_store_bonding_information(sm_conn); 1718 sm_done_for_handle(sm_conn->sm_handle); 1719 break; 1720 #endif 1721 default: 1722 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1723 break; 1724 } 1725 sm_trigger_run(); 1726 } 1727 1728 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){ 1729 const uint16_t message_len = 65; 1730 sm_cmac_connection = sm_conn; 1731 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1732 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1733 sm_cmac_sc_buffer[64] = z; 1734 log_info("f4 key"); 1735 log_info_hexdump(x, 16); 1736 log_info("f4 message"); 1737 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1738 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1739 } 1740 1741 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1742 static const uint8_t f5_length[] = { 0x01, 0x00}; 1743 1744 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1745 1746 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1747 1748 log_info("f5_calculate_salt"); 1749 // calculate salt for f5 1750 const uint16_t message_len = 32; 1751 sm_cmac_connection = sm_conn; 1752 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1753 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1754 } 1755 1756 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){ 1757 const uint16_t message_len = 53; 1758 sm_cmac_connection = sm_conn; 1759 1760 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1761 sm_cmac_sc_buffer[0] = 0; 1762 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1763 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1764 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1765 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1766 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1767 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1768 log_info("f5 key"); 1769 log_info_hexdump(t, 16); 1770 log_info("f5 message for MacKey"); 1771 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1772 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1773 } 1774 1775 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1776 sm_key56_t bd_addr_master, bd_addr_slave; 1777 bd_addr_master[0] = setup->sm_m_addr_type; 1778 bd_addr_slave[0] = setup->sm_s_addr_type; 1779 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1780 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1781 if (IS_RESPONDER(sm_conn->sm_role)){ 1782 // responder 1783 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1784 } else { 1785 // initiator 1786 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1787 } 1788 } 1789 1790 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1791 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1792 const uint16_t message_len = 53; 1793 sm_cmac_connection = sm_conn; 1794 sm_cmac_sc_buffer[0] = 1; 1795 // 1..52 setup before 1796 log_info("f5 key"); 1797 log_info_hexdump(t, 16); 1798 log_info("f5 message for LTK"); 1799 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1800 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1801 } 1802 1803 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1804 f5_ltk(sm_conn, setup->sm_t); 1805 } 1806 1807 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){ 1808 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1809 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1810 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1811 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1812 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1813 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1814 } 1815 1816 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1817 const uint16_t message_len = 65; 1818 sm_cmac_connection = sm_conn; 1819 log_info("f6 key"); 1820 log_info_hexdump(w, 16); 1821 log_info("f6 message"); 1822 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1823 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1824 } 1825 1826 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1827 // - U is 256 bits 1828 // - V is 256 bits 1829 // - X is 128 bits 1830 // - Y is 128 bits 1831 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){ 1832 const uint16_t message_len = 80; 1833 sm_cmac_connection = sm_conn; 1834 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1835 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1836 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1837 log_info("g2 key"); 1838 log_info_hexdump(x, 16); 1839 log_info("g2 message"); 1840 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1841 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1842 } 1843 1844 static void g2_calculate(sm_connection_t * sm_conn) { 1845 // calc Va if numeric comparison 1846 if (IS_RESPONDER(sm_conn->sm_role)){ 1847 // responder 1848 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1849 } else { 1850 // initiator 1851 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1852 } 1853 } 1854 1855 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1856 uint8_t z = 0; 1857 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1858 // some form of passkey 1859 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1860 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1861 setup->sm_passkey_bit++; 1862 } 1863 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1864 } 1865 1866 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1867 // OOB 1868 if (setup->sm_stk_generation_method == OOB){ 1869 if (IS_RESPONDER(sm_conn->sm_role)){ 1870 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1871 } else { 1872 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1873 } 1874 return; 1875 } 1876 1877 uint8_t z = 0; 1878 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1879 // some form of passkey 1880 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1881 // sm_passkey_bit was increased before sending confirm value 1882 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1883 } 1884 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1885 } 1886 1887 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1888 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1889 1890 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1891 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1892 return; 1893 } else { 1894 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1895 } 1896 } 1897 1898 static void sm_sc_dhkey_calculated(void * arg){ 1899 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1900 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1901 if (sm_conn == NULL) return; 1902 1903 log_info("dhkey"); 1904 log_info_hexdump(&setup->sm_dhkey[0], 32); 1905 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1906 // trigger next step 1907 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1908 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1909 } 1910 sm_trigger_run(); 1911 } 1912 1913 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1914 // calculate DHKCheck 1915 sm_key56_t bd_addr_master, bd_addr_slave; 1916 bd_addr_master[0] = setup->sm_m_addr_type; 1917 bd_addr_slave[0] = setup->sm_s_addr_type; 1918 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1919 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1920 uint8_t iocap_a[3]; 1921 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1922 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1923 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1924 uint8_t iocap_b[3]; 1925 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1926 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1927 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1928 if (IS_RESPONDER(sm_conn->sm_role)){ 1929 // responder 1930 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1931 f6_engine(sm_conn, setup->sm_mackey); 1932 } else { 1933 // initiator 1934 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1935 f6_engine(sm_conn, setup->sm_mackey); 1936 } 1937 } 1938 1939 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1940 // validate E = f6() 1941 sm_key56_t bd_addr_master, bd_addr_slave; 1942 bd_addr_master[0] = setup->sm_m_addr_type; 1943 bd_addr_slave[0] = setup->sm_s_addr_type; 1944 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1945 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1946 1947 uint8_t iocap_a[3]; 1948 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1949 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1950 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1951 uint8_t iocap_b[3]; 1952 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1953 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1954 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1955 if (IS_RESPONDER(sm_conn->sm_role)){ 1956 // responder 1957 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1958 f6_engine(sm_conn, setup->sm_mackey); 1959 } else { 1960 // initiator 1961 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1962 f6_engine(sm_conn, setup->sm_mackey); 1963 } 1964 } 1965 1966 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1967 1968 // 1969 // Link Key Conversion Function h6 1970 // 1971 // h6(W, keyID) = AES-CMAC_W(keyID) 1972 // - W is 128 bits 1973 // - keyID is 32 bits 1974 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1975 const uint16_t message_len = 4; 1976 sm_cmac_connection = sm_conn; 1977 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1978 log_info("h6 key"); 1979 log_info_hexdump(w, 16); 1980 log_info("h6 message"); 1981 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1982 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1983 } 1984 // 1985 // Link Key Conversion Function h7 1986 // 1987 // h7(SALT, W) = AES-CMAC_SALT(W) 1988 // - SALT is 128 bits 1989 // - W is 128 bits 1990 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1991 const uint16_t message_len = 16; 1992 sm_cmac_connection = sm_conn; 1993 log_info("h7 key"); 1994 log_info_hexdump(salt, 16); 1995 log_info("h7 message"); 1996 log_info_hexdump(w, 16); 1997 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1998 } 1999 2000 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2001 // Errata Service Release to the Bluetooth Specification: ESR09 2002 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2003 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2004 2005 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2006 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2007 } 2008 2009 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2010 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2011 } 2012 2013 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2014 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2015 } 2016 2017 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2018 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2019 } 2020 2021 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2022 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2023 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2024 } 2025 2026 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2027 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2028 h7_engine(sm_conn, salt, setup->sm_link_key); 2029 } 2030 2031 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2032 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2033 btstack_assert(hci_connection != NULL); 2034 reverse_128(hci_connection->link_key, setup->sm_link_key); 2035 setup->sm_link_key_type = hci_connection->link_key_type; 2036 } 2037 2038 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2039 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; 2040 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2041 } 2042 2043 #endif 2044 2045 #endif 2046 2047 // key management legacy connections: 2048 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2049 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2050 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2051 // - responder reconnects: responder uses LTK receveived from master 2052 2053 // key management secure connections: 2054 // - both devices store same LTK from ECDH key exchange. 2055 2056 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2057 static void sm_load_security_info(sm_connection_t * sm_connection){ 2058 int encryption_key_size; 2059 int authenticated; 2060 int authorized; 2061 int secure_connection; 2062 2063 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2064 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2065 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2066 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); 2067 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2068 sm_connection->sm_connection_authenticated = authenticated; 2069 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2070 sm_connection->sm_connection_sc = secure_connection; 2071 } 2072 #endif 2073 2074 #ifdef ENABLE_LE_PERIPHERAL 2075 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2076 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2077 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2078 // re-establish used key encryption size 2079 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2080 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2081 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2082 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2083 // Legacy paring -> not SC 2084 sm_connection->sm_connection_sc = 0; 2085 log_info("sm: received ltk request with key size %u, authenticated %u", 2086 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2087 } 2088 #endif 2089 2090 // distributed key generation 2091 static bool sm_run_dpkg(void){ 2092 switch (dkg_state){ 2093 case DKG_CALC_IRK: 2094 // already busy? 2095 if (sm_aes128_state == SM_AES128_IDLE) { 2096 log_info("DKG_CALC_IRK started"); 2097 // IRK = d1(IR, 1, 0) 2098 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2099 sm_aes128_state = SM_AES128_ACTIVE; 2100 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2101 return true; 2102 } 2103 break; 2104 case DKG_CALC_DHK: 2105 // already busy? 2106 if (sm_aes128_state == SM_AES128_IDLE) { 2107 log_info("DKG_CALC_DHK started"); 2108 // DHK = d1(IR, 3, 0) 2109 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2110 sm_aes128_state = SM_AES128_ACTIVE; 2111 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2112 return true; 2113 } 2114 break; 2115 default: 2116 break; 2117 } 2118 return false; 2119 } 2120 2121 // random address updates 2122 static bool sm_run_rau(void){ 2123 switch (rau_state){ 2124 case RAU_GET_RANDOM: 2125 rau_state = RAU_W4_RANDOM; 2126 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2127 return true; 2128 case RAU_GET_ENC: 2129 // already busy? 2130 if (sm_aes128_state == SM_AES128_IDLE) { 2131 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2132 sm_aes128_state = SM_AES128_ACTIVE; 2133 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2134 return true; 2135 } 2136 break; 2137 default: 2138 break; 2139 } 2140 return false; 2141 } 2142 2143 // CSRK Lookup 2144 static bool sm_run_csrk(void){ 2145 btstack_linked_list_iterator_t it; 2146 2147 // -- if csrk lookup ready, find connection that require csrk lookup 2148 if (sm_address_resolution_idle()){ 2149 hci_connections_get_iterator(&it); 2150 while(btstack_linked_list_iterator_has_next(&it)){ 2151 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2152 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2153 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2154 // and start lookup 2155 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); 2156 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2157 break; 2158 } 2159 } 2160 } 2161 2162 // -- if csrk lookup ready, resolved addresses for received addresses 2163 if (sm_address_resolution_idle()) { 2164 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2165 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2166 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2167 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2168 btstack_memory_sm_lookup_entry_free(entry); 2169 } 2170 } 2171 2172 // -- Continue with CSRK device lookup by public or resolvable private address 2173 if (!sm_address_resolution_idle()){ 2174 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2175 while (sm_address_resolution_test < le_device_db_max_count()){ 2176 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2177 bd_addr_t addr; 2178 sm_key_t irk; 2179 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2180 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2181 2182 // skip unused entries 2183 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2184 sm_address_resolution_test++; 2185 continue; 2186 } 2187 2188 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2189 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2190 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2191 break; 2192 } 2193 2194 // if connection type is public, it must be a different one 2195 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2196 sm_address_resolution_test++; 2197 continue; 2198 } 2199 2200 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2201 2202 log_info("LE Device Lookup: calculate AH"); 2203 log_info_key("IRK", irk); 2204 2205 (void)memcpy(sm_aes128_key, irk, 16); 2206 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2207 sm_address_resolution_ah_calculation_active = 1; 2208 sm_aes128_state = SM_AES128_ACTIVE; 2209 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2210 return true; 2211 } 2212 2213 if (sm_address_resolution_test >= le_device_db_max_count()){ 2214 log_info("LE Device Lookup: not found"); 2215 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2216 } 2217 } 2218 return false; 2219 } 2220 2221 // SC OOB 2222 static bool sm_run_oob(void){ 2223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2224 switch (sm_sc_oob_state){ 2225 case SM_SC_OOB_W2_CALC_CONFIRM: 2226 if (!sm_cmac_ready()) break; 2227 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2228 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2229 return true; 2230 default: 2231 break; 2232 } 2233 #endif 2234 return false; 2235 } 2236 2237 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2238 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2239 } 2240 2241 // handle basic actions that don't requires the full context 2242 static bool sm_run_basic(void){ 2243 btstack_linked_list_iterator_t it; 2244 hci_connections_get_iterator(&it); 2245 while(btstack_linked_list_iterator_has_next(&it)){ 2246 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2247 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2248 switch(sm_connection->sm_engine_state){ 2249 2250 // general 2251 case SM_GENERAL_SEND_PAIRING_FAILED: { 2252 uint8_t buffer[2]; 2253 buffer[0] = SM_CODE_PAIRING_FAILED; 2254 buffer[1] = sm_connection->sm_pairing_failed_reason; 2255 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2256 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2257 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2258 sm_done_for_handle(sm_connection->sm_handle); 2259 break; 2260 } 2261 2262 // responder side 2263 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2264 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2265 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2266 return true; 2267 2268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2269 case SM_SC_RECEIVED_LTK_REQUEST: 2270 switch (sm_connection->sm_irk_lookup_state){ 2271 case IRK_LOOKUP_FAILED: 2272 log_info("LTK Request: IRK Lookup Failed)"); 2273 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2274 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2275 return true; 2276 default: 2277 break; 2278 } 2279 break; 2280 #endif 2281 default: 2282 break; 2283 } 2284 } 2285 return false; 2286 } 2287 2288 static void sm_run_activate_connection(void){ 2289 // Find connections that requires setup context and make active if no other is locked 2290 btstack_linked_list_iterator_t it; 2291 hci_connections_get_iterator(&it); 2292 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2293 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2294 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2295 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2296 bool done = true; 2297 int err; 2298 UNUSED(err); 2299 2300 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2301 // assert ec key is ready 2302 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2303 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2304 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2305 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2306 sm_ec_generate_new_key(); 2307 } 2308 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2309 continue; 2310 } 2311 } 2312 #endif 2313 2314 switch (sm_connection->sm_engine_state) { 2315 #ifdef ENABLE_LE_PERIPHERAL 2316 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2317 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2318 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2319 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2320 case SM_SC_RECEIVED_LTK_REQUEST: 2321 #endif 2322 #endif 2323 #ifdef ENABLE_LE_CENTRAL 2324 case SM_INITIATOR_PH4_HAS_LTK: 2325 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2326 #endif 2327 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2328 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2329 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2330 #endif 2331 // just lock context 2332 break; 2333 default: 2334 done = false; 2335 break; 2336 } 2337 if (done){ 2338 sm_active_connection_handle = sm_connection->sm_handle; 2339 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); 2340 } 2341 } 2342 } 2343 2344 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2345 int i; 2346 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2347 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2348 uint8_t action = 0; 2349 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2350 if (flags & (1u<<i)){ 2351 bool clear_flag = true; 2352 switch (i){ 2353 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2354 case SM_KEYPRESS_PASSKEY_CLEARED: 2355 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2356 default: 2357 break; 2358 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2359 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2360 num_actions--; 2361 clear_flag = num_actions == 0u; 2362 break; 2363 } 2364 if (clear_flag){ 2365 flags &= ~(1<<i); 2366 } 2367 action = i; 2368 break; 2369 } 2370 } 2371 setup->sm_keypress_notification = (num_actions << 5) | flags; 2372 2373 // send keypress notification 2374 uint8_t buffer[2]; 2375 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2376 buffer[1] = action; 2377 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2378 2379 // try 2380 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2381 } 2382 2383 static void sm_run_distribute_keys(sm_connection_t * connection){ 2384 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2385 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2386 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2387 uint8_t buffer[17]; 2388 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2389 reverse_128(setup->sm_ltk, &buffer[1]); 2390 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2391 sm_timeout_reset(connection); 2392 return; 2393 } 2394 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2395 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2396 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2397 uint8_t buffer[11]; 2398 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2399 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2400 reverse_64(setup->sm_local_rand, &buffer[3]); 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_INFORMATION){ 2406 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2407 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2408 uint8_t buffer[17]; 2409 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2410 reverse_128(sm_persistent_irk, &buffer[1]); 2411 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2412 sm_timeout_reset(connection); 2413 return; 2414 } 2415 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2416 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2417 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2418 bd_addr_t local_address; 2419 uint8_t buffer[8]; 2420 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2421 switch (gap_random_address_get_mode()){ 2422 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2423 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2424 // public or static random 2425 gap_le_get_own_address(&buffer[1], local_address); 2426 break; 2427 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2428 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2429 // fallback to public 2430 gap_local_bd_addr(local_address); 2431 buffer[1] = 0; 2432 break; 2433 default: 2434 btstack_assert(false); 2435 break; 2436 } 2437 reverse_bd_addr(local_address, &buffer[2]); 2438 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2439 sm_timeout_reset(connection); 2440 return; 2441 } 2442 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2443 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2444 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2445 2446 #ifdef ENABLE_LE_SIGNED_WRITE 2447 // hack to reproduce test runs 2448 if (test_use_fixed_local_csrk){ 2449 memset(setup->sm_local_csrk, 0xcc, 16); 2450 } 2451 2452 // store local CSRK 2453 if (setup->sm_le_device_index >= 0){ 2454 log_info("sm: store local CSRK"); 2455 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2456 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2457 } 2458 #endif 2459 2460 uint8_t buffer[17]; 2461 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2462 reverse_128(setup->sm_local_csrk, &buffer[1]); 2463 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2464 sm_timeout_reset(connection); 2465 return; 2466 } 2467 btstack_assert(false); 2468 } 2469 2470 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2471 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2472 // requirements to derive link key from LE: 2473 // - use secure connections 2474 if (setup->sm_use_secure_connections == 0) return false; 2475 // - bonding needs to be enabled: 2476 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; 2477 if (!bonding_enabled) return false; 2478 // - need identity address / public addr 2479 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2480 if (!have_identity_address_info) return false; 2481 // - 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) 2482 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2483 // If SC is authenticated, we consider it safe to overwrite a stored key. 2484 // 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. 2485 uint8_t link_key[16]; 2486 link_key_type_t link_key_type; 2487 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2488 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2489 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2490 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2491 return false; 2492 } 2493 // get started (all of the above are true) 2494 return true; 2495 #else 2496 UNUSED(sm_connection); 2497 return false; 2498 #endif 2499 } 2500 2501 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2502 if (sm_ctkd_from_le(connection)){ 2503 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; 2504 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2505 } else { 2506 connection->sm_engine_state = SM_RESPONDER_IDLE; 2507 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2508 sm_done_for_handle(connection->sm_handle); 2509 } 2510 } 2511 2512 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2513 if (sm_ctkd_from_le(connection)){ 2514 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; 2515 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2516 } else { 2517 sm_master_pairing_success(connection); 2518 } 2519 } 2520 2521 static void sm_run(void){ 2522 2523 // assert that stack has already bootet 2524 if (hci_get_state() != HCI_STATE_WORKING) return; 2525 2526 // assert that we can send at least commands 2527 if (!hci_can_send_command_packet_now()) return; 2528 2529 // pause until IR/ER are ready 2530 if (sm_persistent_keys_random_active) return; 2531 2532 bool done; 2533 2534 // 2535 // non-connection related behaviour 2536 // 2537 2538 done = sm_run_dpkg(); 2539 if (done) return; 2540 2541 done = sm_run_rau(); 2542 if (done) return; 2543 2544 done = sm_run_csrk(); 2545 if (done) return; 2546 2547 done = sm_run_oob(); 2548 if (done) return; 2549 2550 // assert that we can send at least commands - cmd might have been sent by crypto engine 2551 if (!hci_can_send_command_packet_now()) return; 2552 2553 // handle basic actions that don't requires the full context 2554 done = sm_run_basic(); 2555 if (done) return; 2556 2557 // 2558 // active connection handling 2559 // -- use loop to handle next connection if lock on setup context is released 2560 2561 while (true) { 2562 2563 sm_run_activate_connection(); 2564 2565 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2566 2567 // 2568 // active connection handling 2569 // 2570 2571 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2572 if (!connection) { 2573 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2574 return; 2575 } 2576 2577 // assert that we could send a SM PDU - not needed for all of the following 2578 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2579 log_info("cannot send now, requesting can send now event"); 2580 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2581 return; 2582 } 2583 2584 // send keypress notifications 2585 if (setup->sm_keypress_notification){ 2586 sm_run_send_keypress_notification(connection); 2587 return; 2588 } 2589 2590 int key_distribution_flags; 2591 UNUSED(key_distribution_flags); 2592 #ifdef ENABLE_LE_PERIPHERAL 2593 int err; 2594 bool have_ltk; 2595 uint8_t ltk[16]; 2596 #endif 2597 2598 log_info("sm_run: state %u", connection->sm_engine_state); 2599 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2600 log_info("sm_run // cannot send"); 2601 } 2602 switch (connection->sm_engine_state){ 2603 2604 // secure connections, initiator + responding states 2605 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2606 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2607 if (!sm_cmac_ready()) break; 2608 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2609 sm_sc_calculate_local_confirm(connection); 2610 break; 2611 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2612 if (!sm_cmac_ready()) break; 2613 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2614 sm_sc_calculate_remote_confirm(connection); 2615 break; 2616 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2617 if (!sm_cmac_ready()) break; 2618 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2619 sm_sc_calculate_f6_for_dhkey_check(connection); 2620 break; 2621 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2622 if (!sm_cmac_ready()) break; 2623 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2624 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2625 break; 2626 case SM_SC_W2_CALCULATE_F5_SALT: 2627 if (!sm_cmac_ready()) break; 2628 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2629 f5_calculate_salt(connection); 2630 break; 2631 case SM_SC_W2_CALCULATE_F5_MACKEY: 2632 if (!sm_cmac_ready()) break; 2633 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2634 f5_calculate_mackey(connection); 2635 break; 2636 case SM_SC_W2_CALCULATE_F5_LTK: 2637 if (!sm_cmac_ready()) break; 2638 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2639 f5_calculate_ltk(connection); 2640 break; 2641 case SM_SC_W2_CALCULATE_G2: 2642 if (!sm_cmac_ready()) break; 2643 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2644 g2_calculate(connection); 2645 break; 2646 #endif 2647 2648 #ifdef ENABLE_LE_CENTRAL 2649 // initiator side 2650 2651 case SM_INITIATOR_PH4_HAS_LTK: { 2652 sm_reset_setup(); 2653 sm_load_security_info(connection); 2654 sm_reencryption_started(connection); 2655 2656 sm_key_t peer_ltk_flipped; 2657 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2658 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2659 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2660 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2661 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2662 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2663 return; 2664 } 2665 2666 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2667 sm_reset_setup(); 2668 sm_init_setup(connection); 2669 sm_timeout_start(connection); 2670 sm_pairing_started(connection); 2671 2672 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2673 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2674 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2675 sm_timeout_reset(connection); 2676 break; 2677 #endif 2678 2679 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2680 2681 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2682 bool trigger_user_response = false; 2683 bool trigger_start_calculating_local_confirm = false; 2684 uint8_t buffer[65]; 2685 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2686 // 2687 reverse_256(&ec_q[0], &buffer[1]); 2688 reverse_256(&ec_q[32], &buffer[33]); 2689 2690 #ifdef ENABLE_TESTING_SUPPORT 2691 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2692 log_info("testing_support: invalidating public key"); 2693 // flip single bit of public key coordinate 2694 buffer[1] ^= 1; 2695 } 2696 #endif 2697 2698 // stk generation method 2699 // passkey entry: notify app to show passkey or to request passkey 2700 switch (setup->sm_stk_generation_method){ 2701 case JUST_WORKS: 2702 case NUMERIC_COMPARISON: 2703 if (IS_RESPONDER(connection->sm_role)){ 2704 // responder 2705 trigger_start_calculating_local_confirm = true; 2706 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2707 } else { 2708 // initiator 2709 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2710 } 2711 break; 2712 case PK_INIT_INPUT: 2713 case PK_RESP_INPUT: 2714 case PK_BOTH_INPUT: 2715 // use random TK for display 2716 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2717 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2718 setup->sm_passkey_bit = 0; 2719 2720 if (IS_RESPONDER(connection->sm_role)){ 2721 // responder 2722 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2723 } else { 2724 // initiator 2725 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2726 } 2727 trigger_user_response = true; 2728 break; 2729 case OOB: 2730 if (IS_RESPONDER(connection->sm_role)){ 2731 // responder 2732 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2733 } else { 2734 // initiator 2735 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2736 } 2737 break; 2738 default: 2739 btstack_assert(false); 2740 break; 2741 } 2742 2743 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2744 sm_timeout_reset(connection); 2745 2746 // trigger user response and calc confirm after sending pdu 2747 if (trigger_user_response){ 2748 sm_trigger_user_response(connection); 2749 } 2750 if (trigger_start_calculating_local_confirm){ 2751 sm_sc_start_calculating_local_confirm(connection); 2752 } 2753 break; 2754 } 2755 case SM_SC_SEND_CONFIRMATION: { 2756 uint8_t buffer[17]; 2757 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2758 reverse_128(setup->sm_local_confirm, &buffer[1]); 2759 if (IS_RESPONDER(connection->sm_role)){ 2760 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2761 } else { 2762 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2763 } 2764 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2765 sm_timeout_reset(connection); 2766 break; 2767 } 2768 case SM_SC_SEND_PAIRING_RANDOM: { 2769 uint8_t buffer[17]; 2770 buffer[0] = SM_CODE_PAIRING_RANDOM; 2771 reverse_128(setup->sm_local_nonce, &buffer[1]); 2772 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2773 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2774 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2775 if (IS_RESPONDER(connection->sm_role)){ 2776 // responder 2777 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2778 } else { 2779 // initiator 2780 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2781 } 2782 } else { 2783 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2784 if (IS_RESPONDER(connection->sm_role)){ 2785 // responder 2786 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2787 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2788 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2789 } else { 2790 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2791 sm_sc_prepare_dhkey_check(connection); 2792 } 2793 } else { 2794 // initiator 2795 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2796 } 2797 } 2798 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2799 sm_timeout_reset(connection); 2800 break; 2801 } 2802 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2803 uint8_t buffer[17]; 2804 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2805 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2806 2807 if (IS_RESPONDER(connection->sm_role)){ 2808 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2809 } else { 2810 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2811 } 2812 2813 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2814 sm_timeout_reset(connection); 2815 break; 2816 } 2817 2818 #endif 2819 2820 #ifdef ENABLE_LE_PERIPHERAL 2821 2822 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2823 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2824 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2825 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2826 sm_timeout_start(connection); 2827 break; 2828 } 2829 2830 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2831 case SM_SC_RECEIVED_LTK_REQUEST: 2832 switch (connection->sm_irk_lookup_state){ 2833 case IRK_LOOKUP_SUCCEEDED: 2834 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2835 // start using context by loading security info 2836 sm_reset_setup(); 2837 sm_load_security_info(connection); 2838 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2839 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2840 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2841 sm_reencryption_started(connection); 2842 sm_trigger_run(); 2843 break; 2844 } 2845 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2846 connection->sm_engine_state = SM_RESPONDER_IDLE; 2847 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2848 return; 2849 default: 2850 // just wait until IRK lookup is completed 2851 break; 2852 } 2853 break; 2854 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2855 2856 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2857 sm_reset_setup(); 2858 2859 // handle Pairing Request with LTK available 2860 switch (connection->sm_irk_lookup_state) { 2861 case IRK_LOOKUP_SUCCEEDED: 2862 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2863 have_ltk = !sm_is_null_key(ltk); 2864 if (have_ltk){ 2865 log_info("pairing request but LTK available"); 2866 // emit re-encryption start/fail sequence 2867 sm_reencryption_started(connection); 2868 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2869 } 2870 break; 2871 default: 2872 break; 2873 } 2874 2875 sm_init_setup(connection); 2876 sm_pairing_started(connection); 2877 2878 // recover pairing request 2879 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2880 err = sm_stk_generation_init(connection); 2881 2882 #ifdef ENABLE_TESTING_SUPPORT 2883 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2884 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2885 err = test_pairing_failure; 2886 } 2887 #endif 2888 if (err != 0){ 2889 sm_pairing_error(connection, err); 2890 sm_trigger_run(); 2891 break; 2892 } 2893 2894 sm_timeout_start(connection); 2895 2896 // generate random number first, if we need to show passkey, otherwise send response 2897 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2898 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2899 break; 2900 } 2901 2902 /* fall through */ 2903 2904 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2905 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2906 2907 // start with initiator key dist flags 2908 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2909 2910 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2911 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2912 if (setup->sm_use_secure_connections){ 2913 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2914 } 2915 #endif 2916 // setup in response 2917 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); 2918 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); 2919 2920 // update key distribution after ENC was dropped 2921 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)); 2922 2923 if (setup->sm_use_secure_connections){ 2924 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2925 } else { 2926 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2927 } 2928 2929 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2930 sm_timeout_reset(connection); 2931 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2932 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2933 sm_trigger_user_response(connection); 2934 } 2935 return; 2936 #endif 2937 2938 case SM_PH2_SEND_PAIRING_RANDOM: { 2939 uint8_t buffer[17]; 2940 buffer[0] = SM_CODE_PAIRING_RANDOM; 2941 reverse_128(setup->sm_local_random, &buffer[1]); 2942 if (IS_RESPONDER(connection->sm_role)){ 2943 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2944 } else { 2945 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2946 } 2947 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2948 sm_timeout_reset(connection); 2949 break; 2950 } 2951 2952 case SM_PH2_C1_GET_ENC_A: 2953 // already busy? 2954 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2955 // calculate confirm using aes128 engine - step 1 2956 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); 2957 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2958 sm_aes128_state = SM_AES128_ACTIVE; 2959 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); 2960 break; 2961 2962 case SM_PH2_C1_GET_ENC_C: 2963 // already busy? 2964 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2965 // calculate m_confirm using aes128 engine - step 1 2966 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); 2967 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2968 sm_aes128_state = SM_AES128_ACTIVE; 2969 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); 2970 break; 2971 2972 case SM_PH2_CALC_STK: 2973 // already busy? 2974 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2975 // calculate STK 2976 if (IS_RESPONDER(connection->sm_role)){ 2977 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2978 } else { 2979 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2980 } 2981 connection->sm_engine_state = SM_PH2_W4_STK; 2982 sm_aes128_state = SM_AES128_ACTIVE; 2983 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); 2984 break; 2985 2986 case SM_PH3_Y_GET_ENC: 2987 // already busy? 2988 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2989 // PH3B2 - calculate Y from - enc 2990 2991 // dm helper (was sm_dm_r_prime) 2992 // r' = padding || r 2993 // r - 64 bit value 2994 memset(&sm_aes128_plaintext[0], 0, 8); 2995 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2996 2997 // Y = dm(DHK, Rand) 2998 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2999 sm_aes128_state = SM_AES128_ACTIVE; 3000 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); 3001 break; 3002 3003 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3004 uint8_t buffer[17]; 3005 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3006 reverse_128(setup->sm_local_confirm, &buffer[1]); 3007 if (IS_RESPONDER(connection->sm_role)){ 3008 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3009 } else { 3010 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3011 } 3012 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3013 sm_timeout_reset(connection); 3014 return; 3015 } 3016 #ifdef ENABLE_LE_PERIPHERAL 3017 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3018 sm_key_t stk_flipped; 3019 reverse_128(setup->sm_ltk, stk_flipped); 3020 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3021 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3022 return; 3023 } 3024 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3025 // allow to override LTK 3026 if (sm_get_ltk_callback != NULL){ 3027 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3028 } 3029 sm_key_t ltk_flipped; 3030 reverse_128(setup->sm_ltk, ltk_flipped); 3031 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3032 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3033 return; 3034 } 3035 3036 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3037 // already busy? 3038 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3039 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3040 3041 sm_reset_setup(); 3042 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3043 3044 sm_reencryption_started(connection); 3045 3046 // dm helper (was sm_dm_r_prime) 3047 // r' = padding || r 3048 // r - 64 bit value 3049 memset(&sm_aes128_plaintext[0], 0, 8); 3050 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3051 3052 // Y = dm(DHK, Rand) 3053 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3054 sm_aes128_state = SM_AES128_ACTIVE; 3055 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); 3056 return; 3057 #endif 3058 #ifdef ENABLE_LE_CENTRAL 3059 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3060 sm_key_t stk_flipped; 3061 reverse_128(setup->sm_ltk, stk_flipped); 3062 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3063 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3064 return; 3065 } 3066 #endif 3067 3068 case SM_PH3_DISTRIBUTE_KEYS: 3069 // send next key 3070 if (setup->sm_key_distribution_send_set != 0){ 3071 sm_run_distribute_keys(connection); 3072 } 3073 3074 // more to send? 3075 if (setup->sm_key_distribution_send_set != 0){ 3076 return; 3077 } 3078 3079 // keys are sent 3080 if (IS_RESPONDER(connection->sm_role)){ 3081 // slave -> receive master keys if any 3082 if (sm_key_distribution_all_received()){ 3083 sm_key_distribution_handle_all_received(connection); 3084 sm_key_distribution_complete_responder(connection); 3085 // start CTKD right away 3086 continue; 3087 } else { 3088 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3089 } 3090 } else { 3091 sm_master_pairing_success(connection); 3092 } 3093 break; 3094 3095 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3096 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3097 // fill in sm setup (lite version of sm_init_setup) 3098 sm_reset_setup(); 3099 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3100 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3101 setup->sm_s_addr_type = connection->sm_own_addr_type; 3102 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3103 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3104 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3105 setup->sm_use_secure_connections = true; 3106 sm_ctkd_fetch_br_edr_link_key(connection); 3107 3108 // Enc Key and IRK if requested 3109 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3110 #ifdef ENABLE_LE_SIGNED_WRITE 3111 // Plus signing key if supported 3112 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3113 #endif 3114 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3115 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3116 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3117 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3118 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3119 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3120 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3121 3122 // set state and send pairing response 3123 sm_timeout_start(connection); 3124 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3125 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3126 break; 3127 3128 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3129 // fill in sm setup (lite version of sm_init_setup) 3130 sm_reset_setup(); 3131 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3132 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3133 setup->sm_s_addr_type = connection->sm_own_addr_type; 3134 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3135 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3136 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3137 setup->sm_use_secure_connections = true; 3138 sm_ctkd_fetch_br_edr_link_key(connection); 3139 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3140 3141 // Enc Key and IRK if requested 3142 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3143 #ifdef ENABLE_LE_SIGNED_WRITE 3144 // Plus signing key if supported 3145 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3146 #endif 3147 // drop flags not requested by initiator 3148 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3149 3150 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3151 // - the IO Capability field, 3152 // - the OOB data flag field, and 3153 // - all bits in the Auth Req field except the CT2 bit. 3154 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3155 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3156 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3157 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3158 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3159 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3160 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3161 3162 // configure key distribution, LTK is derived locally 3163 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3164 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3165 3166 // set state and send pairing response 3167 sm_timeout_start(connection); 3168 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3169 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3170 break; 3171 case SM_BR_EDR_DISTRIBUTE_KEYS: 3172 if (setup->sm_key_distribution_send_set != 0) { 3173 sm_run_distribute_keys(connection); 3174 return; 3175 } 3176 // keys are sent 3177 if (IS_RESPONDER(connection->sm_role)) { 3178 // responder -> receive master keys if there are any 3179 if (!sm_key_distribution_all_received()){ 3180 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3181 break; 3182 } 3183 } 3184 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3185 sm_ctkd_start_from_br_edr(connection); 3186 continue; 3187 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3188 if (!sm_cmac_ready()) break; 3189 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3190 h6_calculate_ilk_from_le_ltk(connection); 3191 break; 3192 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3193 if (!sm_cmac_ready()) break; 3194 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3195 h6_calculate_br_edr_link_key(connection); 3196 break; 3197 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3198 if (!sm_cmac_ready()) break; 3199 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3200 h7_calculate_ilk_from_le_ltk(connection); 3201 break; 3202 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3203 if (!sm_cmac_ready()) break; 3204 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3205 h6_calculate_ilk_from_br_edr(connection); 3206 break; 3207 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3208 if (!sm_cmac_ready()) break; 3209 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3210 h6_calculate_le_ltk(connection); 3211 break; 3212 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3213 if (!sm_cmac_ready()) break; 3214 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3215 h7_calculate_ilk_from_br_edr(connection); 3216 break; 3217 #endif 3218 3219 default: 3220 break; 3221 } 3222 3223 // check again if active connection was released 3224 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3225 } 3226 } 3227 3228 // sm_aes128_state stays active 3229 static void sm_handle_encryption_result_enc_a(void *arg){ 3230 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3231 sm_aes128_state = SM_AES128_IDLE; 3232 3233 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3234 if (connection == NULL) return; 3235 3236 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3237 sm_aes128_state = SM_AES128_ACTIVE; 3238 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); 3239 } 3240 3241 static void sm_handle_encryption_result_enc_b(void *arg){ 3242 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3243 sm_aes128_state = SM_AES128_IDLE; 3244 3245 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3246 if (connection == NULL) return; 3247 3248 log_info_key("c1!", setup->sm_local_confirm); 3249 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3250 sm_trigger_run(); 3251 } 3252 3253 // sm_aes128_state stays active 3254 static void sm_handle_encryption_result_enc_c(void *arg){ 3255 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3256 sm_aes128_state = SM_AES128_IDLE; 3257 3258 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3259 if (connection == NULL) return; 3260 3261 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3262 sm_aes128_state = SM_AES128_ACTIVE; 3263 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); 3264 } 3265 3266 static void sm_handle_encryption_result_enc_d(void * arg){ 3267 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3268 sm_aes128_state = SM_AES128_IDLE; 3269 3270 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3271 if (connection == NULL) return; 3272 3273 log_info_key("c1!", sm_aes128_ciphertext); 3274 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3275 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3276 sm_trigger_run(); 3277 return; 3278 } 3279 if (IS_RESPONDER(connection->sm_role)){ 3280 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3281 sm_trigger_run(); 3282 } else { 3283 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3284 sm_aes128_state = SM_AES128_ACTIVE; 3285 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); 3286 } 3287 } 3288 3289 static void sm_handle_encryption_result_enc_stk(void *arg){ 3290 sm_aes128_state = SM_AES128_IDLE; 3291 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3292 3293 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3294 if (connection == NULL) return; 3295 3296 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3297 log_info_key("stk", setup->sm_ltk); 3298 if (IS_RESPONDER(connection->sm_role)){ 3299 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3300 } else { 3301 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3302 } 3303 sm_trigger_run(); 3304 } 3305 3306 // sm_aes128_state stays active 3307 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3308 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3309 sm_aes128_state = SM_AES128_IDLE; 3310 3311 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3312 if (connection == NULL) return; 3313 3314 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3315 log_info_hex16("y", setup->sm_local_y); 3316 // PH3B3 - calculate EDIV 3317 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3318 log_info_hex16("ediv", setup->sm_local_ediv); 3319 // PH3B4 - calculate LTK - enc 3320 // LTK = d1(ER, DIV, 0)) 3321 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3322 sm_aes128_state = SM_AES128_ACTIVE; 3323 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); 3324 } 3325 3326 #ifdef ENABLE_LE_PERIPHERAL 3327 // sm_aes128_state stays active 3328 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3329 sm_aes128_state = SM_AES128_IDLE; 3330 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3331 3332 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3333 if (connection == NULL) return; 3334 3335 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3336 log_info_hex16("y", setup->sm_local_y); 3337 3338 // PH3B3 - calculate DIV 3339 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3340 log_info_hex16("ediv", setup->sm_local_ediv); 3341 // PH3B4 - calculate LTK - enc 3342 // LTK = d1(ER, DIV, 0)) 3343 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3344 sm_aes128_state = SM_AES128_ACTIVE; 3345 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); 3346 } 3347 #endif 3348 3349 // sm_aes128_state stays active 3350 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3351 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3352 sm_aes128_state = SM_AES128_IDLE; 3353 3354 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3355 if (connection == NULL) return; 3356 3357 log_info_key("ltk", setup->sm_ltk); 3358 // calc CSRK next 3359 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3360 sm_aes128_state = SM_AES128_ACTIVE; 3361 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); 3362 } 3363 3364 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3365 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3366 sm_aes128_state = SM_AES128_IDLE; 3367 3368 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3369 if (connection == NULL) return; 3370 3371 sm_aes128_state = SM_AES128_IDLE; 3372 log_info_key("csrk", setup->sm_local_csrk); 3373 if (setup->sm_key_distribution_send_set){ 3374 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3375 } else { 3376 // no keys to send, just continue 3377 if (IS_RESPONDER(connection->sm_role)){ 3378 if (sm_key_distribution_all_received()){ 3379 sm_key_distribution_handle_all_received(connection); 3380 sm_key_distribution_complete_responder(connection); 3381 } else { 3382 // slave -> receive master keys 3383 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3384 } 3385 } else { 3386 sm_key_distribution_complete_initiator(connection); 3387 } 3388 } 3389 sm_trigger_run(); 3390 } 3391 3392 #ifdef ENABLE_LE_PERIPHERAL 3393 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3394 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3395 sm_aes128_state = SM_AES128_IDLE; 3396 3397 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3398 if (connection == NULL) return; 3399 3400 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3401 log_info_key("ltk", setup->sm_ltk); 3402 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3403 sm_trigger_run(); 3404 } 3405 #endif 3406 3407 static void sm_handle_encryption_result_address_resolution(void *arg){ 3408 UNUSED(arg); 3409 sm_aes128_state = SM_AES128_IDLE; 3410 3411 sm_address_resolution_ah_calculation_active = 0; 3412 // compare calulated address against connecting device 3413 uint8_t * hash = &sm_aes128_ciphertext[13]; 3414 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3415 log_info("LE Device Lookup: matched resolvable private address"); 3416 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3417 sm_trigger_run(); 3418 return; 3419 } 3420 // no match, try next 3421 sm_address_resolution_test++; 3422 sm_trigger_run(); 3423 } 3424 3425 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3426 UNUSED(arg); 3427 sm_aes128_state = SM_AES128_IDLE; 3428 3429 log_info_key("irk", sm_persistent_irk); 3430 dkg_state = DKG_CALC_DHK; 3431 sm_trigger_run(); 3432 } 3433 3434 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3435 UNUSED(arg); 3436 sm_aes128_state = SM_AES128_IDLE; 3437 3438 log_info_key("dhk", sm_persistent_dhk); 3439 dkg_state = DKG_READY; 3440 sm_trigger_run(); 3441 } 3442 3443 static void sm_handle_encryption_result_rau(void *arg){ 3444 UNUSED(arg); 3445 sm_aes128_state = SM_AES128_IDLE; 3446 3447 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3448 rau_state = RAU_IDLE; 3449 hci_le_random_address_set(sm_random_address); 3450 3451 sm_trigger_run(); 3452 } 3453 3454 static void sm_handle_random_result_rau(void * arg){ 3455 UNUSED(arg); 3456 // non-resolvable vs. resolvable 3457 switch (gap_random_adress_type){ 3458 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3459 // resolvable: use random as prand and calc address hash 3460 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3461 sm_random_address[0u] &= 0x3fu; 3462 sm_random_address[0u] |= 0x40u; 3463 rau_state = RAU_GET_ENC; 3464 break; 3465 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3466 default: 3467 // "The two most significant bits of the address shall be equal to ‘0’"" 3468 sm_random_address[0u] &= 0x3fu; 3469 rau_state = RAU_IDLE; 3470 hci_le_random_address_set(sm_random_address); 3471 break; 3472 } 3473 sm_trigger_run(); 3474 } 3475 3476 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3477 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3478 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3479 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3480 if (connection == NULL) return; 3481 3482 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3483 sm_trigger_run(); 3484 } 3485 3486 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3487 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3488 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3489 if (connection == NULL) return; 3490 3491 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3492 sm_trigger_run(); 3493 } 3494 #endif 3495 3496 static void sm_handle_random_result_ph2_random(void * arg){ 3497 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3498 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3499 if (connection == NULL) return; 3500 3501 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3502 sm_trigger_run(); 3503 } 3504 3505 static void sm_handle_random_result_ph2_tk(void * arg){ 3506 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3507 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3508 if (connection == NULL) return; 3509 3510 sm_reset_tk(); 3511 uint32_t tk; 3512 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3513 // map random to 0-999999 without speding much cycles on a modulus operation 3514 tk = little_endian_read_32(sm_random_data,0); 3515 tk = tk & 0xfffff; // 1048575 3516 if (tk >= 999999u){ 3517 tk = tk - 999999u; 3518 } 3519 } else { 3520 // override with pre-defined passkey 3521 tk = sm_fixed_passkey_in_display_role; 3522 } 3523 big_endian_store_32(setup->sm_tk, 12, tk); 3524 if (IS_RESPONDER(connection->sm_role)){ 3525 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3526 } else { 3527 if (setup->sm_use_secure_connections){ 3528 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3529 } else { 3530 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3531 sm_trigger_user_response(connection); 3532 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3533 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3534 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); 3535 } 3536 } 3537 } 3538 sm_trigger_run(); 3539 } 3540 3541 static void sm_handle_random_result_ph3_div(void * arg){ 3542 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3543 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3544 if (connection == NULL) return; 3545 3546 // use 16 bit from random value as div 3547 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3548 log_info_hex16("div", setup->sm_local_div); 3549 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3550 sm_trigger_run(); 3551 } 3552 3553 static void sm_handle_random_result_ph3_random(void * arg){ 3554 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3555 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3556 if (connection == NULL) return; 3557 3558 reverse_64(sm_random_data, setup->sm_local_rand); 3559 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3560 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3561 // no db for authenticated flag hack: store flag in bit 4 of LSB 3562 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3563 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3564 } 3565 static void sm_validate_er_ir(void){ 3566 // warn about default ER/IR 3567 bool warning = false; 3568 if (sm_ir_is_default()){ 3569 warning = true; 3570 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3571 } 3572 if (sm_er_is_default()){ 3573 warning = true; 3574 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3575 } 3576 if (warning) { 3577 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3578 } 3579 } 3580 3581 static void sm_handle_random_result_ir(void *arg){ 3582 sm_persistent_keys_random_active = false; 3583 if (arg != NULL){ 3584 // key generated, store in tlv 3585 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3586 log_info("Generated IR key. Store in TLV status: %d", status); 3587 UNUSED(status); 3588 } 3589 log_info_key("IR", sm_persistent_ir); 3590 dkg_state = DKG_CALC_IRK; 3591 3592 if (test_use_fixed_local_irk){ 3593 log_info_key("IRK", sm_persistent_irk); 3594 dkg_state = DKG_CALC_DHK; 3595 } 3596 3597 sm_trigger_run(); 3598 } 3599 3600 static void sm_handle_random_result_er(void *arg){ 3601 sm_persistent_keys_random_active = false; 3602 if (arg != 0){ 3603 // key generated, store in tlv 3604 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3605 log_info("Generated ER key. Store in TLV status: %d", status); 3606 UNUSED(status); 3607 } 3608 log_info_key("ER", sm_persistent_er); 3609 3610 // try load ir 3611 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3612 if (key_size == 16){ 3613 // ok, let's continue 3614 log_info("IR from TLV"); 3615 sm_handle_random_result_ir( NULL ); 3616 } else { 3617 // invalid, generate new random one 3618 sm_persistent_keys_random_active = true; 3619 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3620 } 3621 } 3622 3623 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){ 3624 3625 // connection info 3626 sm_conn->sm_handle = con_handle; 3627 sm_conn->sm_role = role; 3628 sm_conn->sm_peer_addr_type = addr_type; 3629 memcpy(sm_conn->sm_peer_address, address, 6); 3630 3631 // security properties 3632 sm_conn->sm_connection_encrypted = 0; 3633 sm_conn->sm_connection_authenticated = 0; 3634 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3635 sm_conn->sm_le_db_index = -1; 3636 sm_conn->sm_reencryption_active = false; 3637 3638 // prepare CSRK lookup (does not involve setup) 3639 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3640 3641 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3642 } 3643 3644 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3645 3646 UNUSED(channel); // ok: there is no channel 3647 UNUSED(size); // ok: fixed format HCI events 3648 3649 sm_connection_t * sm_conn; 3650 hci_con_handle_t con_handle; 3651 uint8_t status; 3652 bd_addr_t addr; 3653 3654 switch (packet_type) { 3655 3656 case HCI_EVENT_PACKET: 3657 switch (hci_event_packet_get_type(packet)) { 3658 3659 case BTSTACK_EVENT_STATE: 3660 switch (btstack_event_state_get_state(packet)){ 3661 case HCI_STATE_WORKING: 3662 log_info("HCI Working!"); 3663 // setup IR/ER with TLV 3664 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3665 if (sm_tlv_impl != NULL){ 3666 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3667 if (key_size == 16){ 3668 // ok, let's continue 3669 log_info("ER from TLV"); 3670 sm_handle_random_result_er( NULL ); 3671 } else { 3672 // invalid, generate random one 3673 sm_persistent_keys_random_active = true; 3674 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3675 } 3676 } else { 3677 sm_validate_er_ir(); 3678 dkg_state = DKG_CALC_IRK; 3679 3680 if (test_use_fixed_local_irk){ 3681 log_info_key("IRK", sm_persistent_irk); 3682 dkg_state = DKG_CALC_DHK; 3683 } 3684 } 3685 3686 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3687 // trigger ECC key generation 3688 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3689 sm_ec_generate_new_key(); 3690 } 3691 #endif 3692 3693 // restart random address updates after power cycle 3694 gap_random_address_set_mode(gap_random_adress_type); 3695 break; 3696 3697 case HCI_STATE_OFF: 3698 case HCI_STATE_HALTING: 3699 // stop random address update 3700 gap_random_address_update_stop(); 3701 // 3702 break; 3703 3704 default: 3705 break; 3706 } 3707 break; 3708 3709 #ifdef ENABLE_CLASSIC 3710 case HCI_EVENT_CONNECTION_COMPLETE: 3711 // ignore if connection failed 3712 if (hci_event_connection_complete_get_status(packet)) return; 3713 3714 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3715 sm_conn = sm_get_connection_for_handle(con_handle); 3716 if (!sm_conn) break; 3717 3718 hci_event_connection_complete_get_bd_addr(packet, addr); 3719 sm_connection_init(sm_conn, 3720 con_handle, 3721 (uint8_t) gap_get_role(con_handle), 3722 BD_ADDR_TYPE_LE_PUBLIC, 3723 addr); 3724 // classic connection corresponds to public le address 3725 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3726 gap_local_bd_addr(sm_conn->sm_own_address); 3727 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3728 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3729 break; 3730 #endif 3731 3732 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3733 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3734 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3735 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3736 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3737 if (sm_conn == NULL) break; 3738 sm_conn->sm_pairing_requested = 1; 3739 break; 3740 #endif 3741 3742 case HCI_EVENT_LE_META: 3743 switch (packet[2]) { 3744 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3745 // ignore if connection failed 3746 if (packet[3]) return; 3747 3748 con_handle = little_endian_read_16(packet, 4); 3749 sm_conn = sm_get_connection_for_handle(con_handle); 3750 if (!sm_conn) break; 3751 3752 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3753 sm_connection_init(sm_conn, 3754 con_handle, 3755 hci_subevent_le_connection_complete_get_role(packet), 3756 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3757 addr); 3758 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3759 3760 // track our addr used for this connection and set state 3761 #ifdef ENABLE_LE_PERIPHERAL 3762 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3763 // responder - use own address from advertisements 3764 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3765 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3766 } 3767 #endif 3768 #ifdef ENABLE_LE_CENTRAL 3769 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3770 // initiator - use own address from create connection 3771 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3772 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3773 } 3774 #endif 3775 break; 3776 3777 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3778 con_handle = little_endian_read_16(packet, 3); 3779 sm_conn = sm_get_connection_for_handle(con_handle); 3780 if (!sm_conn) break; 3781 3782 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3783 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3784 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3785 break; 3786 } 3787 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3788 // PH2 SEND LTK as we need to exchange keys in PH3 3789 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3790 break; 3791 } 3792 3793 // store rand and ediv 3794 reverse_64(&packet[5], sm_conn->sm_local_rand); 3795 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3796 3797 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3798 // potentially stored LTK is from the master 3799 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3800 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3801 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3802 break; 3803 } 3804 // additionally check if remote is in LE Device DB if requested 3805 switch(sm_conn->sm_irk_lookup_state){ 3806 case IRK_LOOKUP_FAILED: 3807 log_info("LTK Request: device not in device db"); 3808 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3809 break; 3810 case IRK_LOOKUP_SUCCEEDED: 3811 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3812 break; 3813 default: 3814 // wait for irk look doen 3815 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3816 break; 3817 } 3818 break; 3819 } 3820 3821 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3822 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3823 #else 3824 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3825 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3826 #endif 3827 break; 3828 3829 default: 3830 break; 3831 } 3832 break; 3833 3834 case HCI_EVENT_ENCRYPTION_CHANGE: 3835 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3836 sm_conn = sm_get_connection_for_handle(con_handle); 3837 if (!sm_conn) break; 3838 3839 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3840 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3841 sm_conn->sm_actual_encryption_key_size); 3842 log_info("event handler, state %u", sm_conn->sm_engine_state); 3843 3844 switch (sm_conn->sm_engine_state){ 3845 3846 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3847 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3848 if (sm_conn->sm_connection_encrypted) { 3849 status = ERROR_CODE_SUCCESS; 3850 if (sm_conn->sm_role){ 3851 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3852 } else { 3853 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3854 } 3855 } else { 3856 status = hci_event_encryption_change_get_status(packet); 3857 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3858 // also, gap_reconnect_security_setup_active will return true 3859 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3860 } 3861 3862 // emit re-encryption complete 3863 sm_reencryption_complete(sm_conn, status); 3864 3865 // notify client, if pairing was requested before 3866 if (sm_conn->sm_pairing_requested){ 3867 sm_conn->sm_pairing_requested = 0; 3868 sm_pairing_complete(sm_conn, status, 0); 3869 } 3870 3871 sm_done_for_handle(sm_conn->sm_handle); 3872 break; 3873 3874 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3875 if (!sm_conn->sm_connection_encrypted) break; 3876 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3877 if (IS_RESPONDER(sm_conn->sm_role)){ 3878 // slave 3879 if (setup->sm_use_secure_connections){ 3880 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3881 } else { 3882 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); 3883 } 3884 } else { 3885 // master 3886 if (sm_key_distribution_all_received()){ 3887 // skip receiving keys as there are none 3888 sm_key_distribution_handle_all_received(sm_conn); 3889 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); 3890 } else { 3891 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3892 } 3893 } 3894 break; 3895 3896 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3897 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3898 if (sm_conn->sm_connection_encrypted != 2) break; 3899 // prepare for pairing request 3900 if (IS_RESPONDER(sm_conn->sm_role)){ 3901 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3902 } else if (sm_conn->sm_pairing_requested){ 3903 // only send LE pairing request after BR/EDR SSP 3904 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3905 } 3906 break; 3907 #endif 3908 default: 3909 break; 3910 } 3911 break; 3912 3913 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3914 con_handle = little_endian_read_16(packet, 3); 3915 sm_conn = sm_get_connection_for_handle(con_handle); 3916 if (!sm_conn) break; 3917 3918 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3919 log_info("event handler, state %u", sm_conn->sm_engine_state); 3920 // continue if part of initial pairing 3921 switch (sm_conn->sm_engine_state){ 3922 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3923 if (sm_conn->sm_role){ 3924 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3925 } else { 3926 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3927 } 3928 sm_done_for_handle(sm_conn->sm_handle); 3929 break; 3930 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3931 if (IS_RESPONDER(sm_conn->sm_role)){ 3932 // slave 3933 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); 3934 } else { 3935 // master 3936 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3937 } 3938 break; 3939 default: 3940 break; 3941 } 3942 break; 3943 3944 3945 case HCI_EVENT_DISCONNECTION_COMPLETE: 3946 con_handle = little_endian_read_16(packet, 3); 3947 sm_done_for_handle(con_handle); 3948 sm_conn = sm_get_connection_for_handle(con_handle); 3949 if (!sm_conn) break; 3950 3951 // pairing failed, if it was ongoing 3952 switch (sm_conn->sm_engine_state){ 3953 case SM_GENERAL_IDLE: 3954 case SM_INITIATOR_CONNECTED: 3955 case SM_RESPONDER_IDLE: 3956 break; 3957 default: 3958 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3959 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3960 break; 3961 } 3962 3963 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3964 sm_conn->sm_handle = 0; 3965 break; 3966 3967 case HCI_EVENT_COMMAND_COMPLETE: 3968 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 3969 // set local addr for le device db 3970 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3971 le_device_db_set_local_bd_addr(addr); 3972 } 3973 break; 3974 default: 3975 break; 3976 } 3977 break; 3978 default: 3979 break; 3980 } 3981 3982 sm_run(); 3983 } 3984 3985 static inline int sm_calc_actual_encryption_key_size(int other){ 3986 if (other < sm_min_encryption_key_size) return 0; 3987 if (other < sm_max_encryption_key_size) return other; 3988 return sm_max_encryption_key_size; 3989 } 3990 3991 3992 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3993 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3994 switch (method){ 3995 case JUST_WORKS: 3996 case NUMERIC_COMPARISON: 3997 return 1; 3998 default: 3999 return 0; 4000 } 4001 } 4002 // responder 4003 4004 static int sm_passkey_used(stk_generation_method_t method){ 4005 switch (method){ 4006 case PK_RESP_INPUT: 4007 return 1; 4008 default: 4009 return 0; 4010 } 4011 } 4012 4013 static int sm_passkey_entry(stk_generation_method_t method){ 4014 switch (method){ 4015 case PK_RESP_INPUT: 4016 case PK_INIT_INPUT: 4017 case PK_BOTH_INPUT: 4018 return 1; 4019 default: 4020 return 0; 4021 } 4022 } 4023 4024 #endif 4025 4026 /** 4027 * @return ok 4028 */ 4029 static int sm_validate_stk_generation_method(void){ 4030 // check if STK generation method is acceptable by client 4031 switch (setup->sm_stk_generation_method){ 4032 case JUST_WORKS: 4033 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4034 case PK_RESP_INPUT: 4035 case PK_INIT_INPUT: 4036 case PK_BOTH_INPUT: 4037 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4038 case OOB: 4039 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4040 case NUMERIC_COMPARISON: 4041 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4042 default: 4043 return 0; 4044 } 4045 } 4046 4047 #ifdef ENABLE_LE_CENTRAL 4048 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4049 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4050 if (sm_sc_only_mode){ 4051 uint8_t auth_req = packet[1]; 4052 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4053 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4054 return; 4055 } 4056 } 4057 #else 4058 UNUSED(packet); 4059 #endif 4060 4061 int have_ltk; 4062 uint8_t ltk[16]; 4063 4064 // IRK complete? 4065 switch (sm_conn->sm_irk_lookup_state){ 4066 case IRK_LOOKUP_FAILED: 4067 // start pairing 4068 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4069 break; 4070 case IRK_LOOKUP_SUCCEEDED: 4071 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4072 have_ltk = !sm_is_null_key(ltk); 4073 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4074 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4075 // start re-encrypt if we have LTK and the connection is not already encrypted 4076 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4077 } else { 4078 // start pairing 4079 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4080 } 4081 break; 4082 default: 4083 // otherwise, store security request 4084 sm_conn->sm_security_request_received = 1; 4085 break; 4086 } 4087 } 4088 #endif 4089 4090 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4091 4092 // size of complete sm_pdu used to validate input 4093 static const uint8_t sm_pdu_size[] = { 4094 0, // 0x00 invalid opcode 4095 7, // 0x01 pairing request 4096 7, // 0x02 pairing response 4097 17, // 0x03 pairing confirm 4098 17, // 0x04 pairing random 4099 2, // 0x05 pairing failed 4100 17, // 0x06 encryption information 4101 11, // 0x07 master identification 4102 17, // 0x08 identification information 4103 8, // 0x09 identify address information 4104 17, // 0x0a signing information 4105 2, // 0x0b security request 4106 65, // 0x0c pairing public key 4107 17, // 0x0d pairing dhk check 4108 2, // 0x0e keypress notification 4109 }; 4110 4111 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4112 sm_run(); 4113 } 4114 4115 if (packet_type != SM_DATA_PACKET) return; 4116 if (size == 0u) return; 4117 4118 uint8_t sm_pdu_code = packet[0]; 4119 4120 // validate pdu size 4121 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 4122 if (sm_pdu_size[sm_pdu_code] != size) return; 4123 4124 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4125 if (!sm_conn) return; 4126 4127 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4128 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4129 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4130 sm_done_for_handle(con_handle); 4131 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4132 return; 4133 } 4134 4135 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4136 4137 int err; 4138 UNUSED(err); 4139 4140 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4141 uint8_t buffer[5]; 4142 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4143 buffer[1] = 3; 4144 little_endian_store_16(buffer, 2, con_handle); 4145 buffer[4] = packet[1]; 4146 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4147 return; 4148 } 4149 4150 switch (sm_conn->sm_engine_state){ 4151 4152 // a sm timeout requires a new physical connection 4153 case SM_GENERAL_TIMEOUT: 4154 return; 4155 4156 #ifdef ENABLE_LE_CENTRAL 4157 4158 // Initiator 4159 case SM_INITIATOR_CONNECTED: 4160 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4161 sm_pdu_received_in_wrong_state(sm_conn); 4162 break; 4163 } 4164 sm_initiator_connected_handle_security_request(sm_conn, packet); 4165 break; 4166 4167 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4168 // Core 5, Vol 3, Part H, 2.4.6: 4169 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4170 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4171 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4172 log_info("Ignoring Security Request"); 4173 break; 4174 } 4175 4176 // all other pdus are incorrect 4177 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4178 sm_pdu_received_in_wrong_state(sm_conn); 4179 break; 4180 } 4181 4182 // store pairing request 4183 (void)memcpy(&setup->sm_s_pres, packet, 4184 sizeof(sm_pairing_packet_t)); 4185 err = sm_stk_generation_init(sm_conn); 4186 4187 #ifdef ENABLE_TESTING_SUPPORT 4188 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4189 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4190 err = test_pairing_failure; 4191 } 4192 #endif 4193 4194 if (err != 0){ 4195 sm_pairing_error(sm_conn, err); 4196 break; 4197 } 4198 4199 // generate random number first, if we need to show passkey 4200 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4201 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); 4202 break; 4203 } 4204 4205 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4206 if (setup->sm_use_secure_connections){ 4207 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4208 if (setup->sm_stk_generation_method == JUST_WORKS){ 4209 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4210 sm_trigger_user_response(sm_conn); 4211 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4212 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4213 } 4214 } else { 4215 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4216 } 4217 break; 4218 } 4219 #endif 4220 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4221 sm_trigger_user_response(sm_conn); 4222 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4223 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4224 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); 4225 } 4226 break; 4227 4228 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4229 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4230 sm_pdu_received_in_wrong_state(sm_conn); 4231 break; 4232 } 4233 4234 // store s_confirm 4235 reverse_128(&packet[1], setup->sm_peer_confirm); 4236 4237 // abort if s_confirm matches m_confirm 4238 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4239 sm_pdu_received_in_wrong_state(sm_conn); 4240 break; 4241 } 4242 4243 #ifdef ENABLE_TESTING_SUPPORT 4244 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4245 log_info("testing_support: reset confirm value"); 4246 memset(setup->sm_peer_confirm, 0, 16); 4247 } 4248 #endif 4249 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4250 break; 4251 4252 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4253 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4254 sm_pdu_received_in_wrong_state(sm_conn); 4255 break;; 4256 } 4257 4258 // received random value 4259 reverse_128(&packet[1], setup->sm_peer_random); 4260 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4261 break; 4262 #endif 4263 4264 #ifdef ENABLE_LE_PERIPHERAL 4265 // Responder 4266 case SM_RESPONDER_IDLE: 4267 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4268 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4269 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4270 sm_pdu_received_in_wrong_state(sm_conn); 4271 break;; 4272 } 4273 4274 // store pairing request 4275 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4276 4277 // check if IRK completed 4278 switch (sm_conn->sm_irk_lookup_state){ 4279 case IRK_LOOKUP_SUCCEEDED: 4280 case IRK_LOOKUP_FAILED: 4281 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4282 break; 4283 default: 4284 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4285 break; 4286 } 4287 break; 4288 #endif 4289 4290 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4291 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4292 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4293 sm_pdu_received_in_wrong_state(sm_conn); 4294 break; 4295 } 4296 4297 // store public key for DH Key calculation 4298 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4299 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4300 4301 // CVE-2020-26558: abort pairing if remote uses the same public key 4302 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4303 log_info("Remote PK matches ours"); 4304 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4305 break; 4306 } 4307 4308 // validate public key 4309 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4310 if (err != 0){ 4311 log_info("sm: peer public key invalid %x", err); 4312 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4313 break; 4314 } 4315 4316 // start calculating dhkey 4317 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); 4318 4319 4320 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4321 if (IS_RESPONDER(sm_conn->sm_role)){ 4322 // responder 4323 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4324 } else { 4325 // initiator 4326 // stk generation method 4327 // passkey entry: notify app to show passkey or to request passkey 4328 switch (setup->sm_stk_generation_method){ 4329 case JUST_WORKS: 4330 case NUMERIC_COMPARISON: 4331 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4332 break; 4333 case PK_RESP_INPUT: 4334 sm_sc_start_calculating_local_confirm(sm_conn); 4335 break; 4336 case PK_INIT_INPUT: 4337 case PK_BOTH_INPUT: 4338 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4339 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4340 break; 4341 } 4342 sm_sc_start_calculating_local_confirm(sm_conn); 4343 break; 4344 case OOB: 4345 // generate Nx 4346 log_info("Generate Na"); 4347 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); 4348 break; 4349 default: 4350 btstack_assert(false); 4351 break; 4352 } 4353 } 4354 break; 4355 4356 case SM_SC_W4_CONFIRMATION: 4357 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4358 sm_pdu_received_in_wrong_state(sm_conn); 4359 break; 4360 } 4361 // received confirm value 4362 reverse_128(&packet[1], setup->sm_peer_confirm); 4363 4364 #ifdef ENABLE_TESTING_SUPPORT 4365 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4366 log_info("testing_support: reset confirm value"); 4367 memset(setup->sm_peer_confirm, 0, 16); 4368 } 4369 #endif 4370 if (IS_RESPONDER(sm_conn->sm_role)){ 4371 // responder 4372 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4373 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4374 // still waiting for passkey 4375 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4376 break; 4377 } 4378 } 4379 sm_sc_start_calculating_local_confirm(sm_conn); 4380 } else { 4381 // initiator 4382 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4383 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); 4384 } else { 4385 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4386 } 4387 } 4388 break; 4389 4390 case SM_SC_W4_PAIRING_RANDOM: 4391 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4392 sm_pdu_received_in_wrong_state(sm_conn); 4393 break; 4394 } 4395 4396 // received random value 4397 reverse_128(&packet[1], setup->sm_peer_nonce); 4398 4399 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4400 // only check for JUST WORK/NC in initiator role OR passkey entry 4401 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4402 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4403 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4404 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4405 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4406 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4407 break; 4408 } 4409 4410 // OOB 4411 if (setup->sm_stk_generation_method == OOB){ 4412 4413 // setup local random, set to zero if remote did not receive our data 4414 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4415 if (IS_RESPONDER(sm_conn->sm_role)){ 4416 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4417 log_info("Reset rb as A does not have OOB data"); 4418 memset(setup->sm_rb, 0, 16); 4419 } else { 4420 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4421 log_info("Use stored rb"); 4422 log_info_hexdump(setup->sm_rb, 16); 4423 } 4424 } else { 4425 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4426 log_info("Reset ra as B does not have OOB data"); 4427 memset(setup->sm_ra, 0, 16); 4428 } else { 4429 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4430 log_info("Use stored ra"); 4431 log_info_hexdump(setup->sm_ra, 16); 4432 } 4433 } 4434 4435 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4436 if (setup->sm_have_oob_data){ 4437 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4438 break; 4439 } 4440 } 4441 4442 // TODO: we only get here for Responder role with JW/NC 4443 sm_sc_state_after_receiving_random(sm_conn); 4444 break; 4445 4446 case SM_SC_W2_CALCULATE_G2: 4447 case SM_SC_W4_CALCULATE_G2: 4448 case SM_SC_W4_CALCULATE_DHKEY: 4449 case SM_SC_W2_CALCULATE_F5_SALT: 4450 case SM_SC_W4_CALCULATE_F5_SALT: 4451 case SM_SC_W2_CALCULATE_F5_MACKEY: 4452 case SM_SC_W4_CALCULATE_F5_MACKEY: 4453 case SM_SC_W2_CALCULATE_F5_LTK: 4454 case SM_SC_W4_CALCULATE_F5_LTK: 4455 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4456 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4457 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4458 case SM_SC_W4_USER_RESPONSE: 4459 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4460 sm_pdu_received_in_wrong_state(sm_conn); 4461 break; 4462 } 4463 // store DHKey Check 4464 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4465 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4466 4467 // have we been only waiting for dhkey check command? 4468 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4469 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4470 } 4471 break; 4472 #endif 4473 4474 #ifdef ENABLE_LE_PERIPHERAL 4475 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4476 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4477 sm_pdu_received_in_wrong_state(sm_conn); 4478 break; 4479 } 4480 4481 // received confirm value 4482 reverse_128(&packet[1], setup->sm_peer_confirm); 4483 4484 #ifdef ENABLE_TESTING_SUPPORT 4485 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4486 log_info("testing_support: reset confirm value"); 4487 memset(setup->sm_peer_confirm, 0, 16); 4488 } 4489 #endif 4490 // notify client to hide shown passkey 4491 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4492 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4493 } 4494 4495 // handle user cancel pairing? 4496 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4497 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4498 break; 4499 } 4500 4501 // wait for user action? 4502 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4503 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4504 break; 4505 } 4506 4507 // calculate and send local_confirm 4508 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); 4509 break; 4510 4511 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4512 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4513 sm_pdu_received_in_wrong_state(sm_conn); 4514 break;; 4515 } 4516 4517 // received random value 4518 reverse_128(&packet[1], setup->sm_peer_random); 4519 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4520 break; 4521 #endif 4522 4523 case SM_PH3_RECEIVE_KEYS: 4524 switch(sm_pdu_code){ 4525 case SM_CODE_ENCRYPTION_INFORMATION: 4526 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4527 reverse_128(&packet[1], setup->sm_peer_ltk); 4528 break; 4529 4530 case SM_CODE_MASTER_IDENTIFICATION: 4531 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4532 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4533 reverse_64(&packet[3], setup->sm_peer_rand); 4534 break; 4535 4536 case SM_CODE_IDENTITY_INFORMATION: 4537 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4538 reverse_128(&packet[1], setup->sm_peer_irk); 4539 break; 4540 4541 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4542 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4543 setup->sm_peer_addr_type = packet[1]; 4544 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4545 break; 4546 4547 case SM_CODE_SIGNING_INFORMATION: 4548 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4549 reverse_128(&packet[1], setup->sm_peer_csrk); 4550 break; 4551 default: 4552 // Unexpected PDU 4553 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4554 break; 4555 } 4556 // done with key distribution? 4557 if (sm_key_distribution_all_received()){ 4558 4559 sm_key_distribution_handle_all_received(sm_conn); 4560 4561 if (IS_RESPONDER(sm_conn->sm_role)){ 4562 sm_key_distribution_complete_responder(sm_conn); 4563 } else { 4564 if (setup->sm_use_secure_connections){ 4565 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4566 } else { 4567 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); 4568 } 4569 } 4570 } 4571 break; 4572 4573 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4574 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4575 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4576 sm_pdu_received_in_wrong_state(sm_conn); 4577 break; 4578 } 4579 // store pairing response 4580 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4581 4582 // validate encryption key size 4583 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)); 4584 // SC Only mandates 128 bit key size 4585 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4586 sm_conn->sm_actual_encryption_key_size = 0; 4587 } 4588 if (sm_conn->sm_actual_encryption_key_size == 0){ 4589 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4590 break; 4591 } 4592 4593 // prepare key exchange, LTK is derived locally 4594 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4595 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4596 4597 // skip receive if there are none 4598 if (sm_key_distribution_all_received()){ 4599 // distribute keys in run handles 'no keys to send' 4600 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4601 } else { 4602 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4603 } 4604 break; 4605 4606 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4607 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4608 sm_pdu_received_in_wrong_state(sm_conn); 4609 break; 4610 } 4611 // store pairing request 4612 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4613 // validate encryption key size 4614 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)); 4615 // SC Only mandates 128 bit key size 4616 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4617 sm_conn->sm_actual_encryption_key_size = 0; 4618 } 4619 if (sm_conn->sm_actual_encryption_key_size == 0){ 4620 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4621 break; 4622 } 4623 // trigger response 4624 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4625 break; 4626 4627 case SM_BR_EDR_RECEIVE_KEYS: 4628 switch(sm_pdu_code){ 4629 case SM_CODE_IDENTITY_INFORMATION: 4630 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4631 reverse_128(&packet[1], setup->sm_peer_irk); 4632 break; 4633 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4634 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4635 setup->sm_peer_addr_type = packet[1]; 4636 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4637 break; 4638 case SM_CODE_SIGNING_INFORMATION: 4639 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4640 reverse_128(&packet[1], setup->sm_peer_csrk); 4641 break; 4642 default: 4643 // Unexpected PDU 4644 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4645 break; 4646 } 4647 4648 // all keys received 4649 if (sm_key_distribution_all_received()){ 4650 if (IS_RESPONDER(sm_conn->sm_role)){ 4651 // responder -> keys exchanged, derive LE LTK 4652 sm_ctkd_start_from_br_edr(sm_conn); 4653 } else { 4654 // initiator -> send our keys if any 4655 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4656 } 4657 } 4658 break; 4659 #endif 4660 4661 default: 4662 // Unexpected PDU 4663 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4664 sm_pdu_received_in_wrong_state(sm_conn); 4665 break; 4666 } 4667 4668 // try to send next pdu 4669 sm_trigger_run(); 4670 } 4671 4672 // Security Manager Client API 4673 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4674 sm_get_oob_data = get_oob_data_callback; 4675 } 4676 4677 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)){ 4678 sm_get_sc_oob_data = get_sc_oob_data_callback; 4679 } 4680 4681 void sm_register_ltk_callback( bool (*get_ltk_callback)(hci_con_handle_t con_handle, uint8_t address_type, bd_addr_t addr, uint8_t * ltk)){ 4682 sm_get_ltk_callback = get_ltk_callback; 4683 } 4684 4685 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4686 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4687 } 4688 4689 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4690 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4691 } 4692 4693 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4694 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4695 } 4696 4697 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4698 sm_min_encryption_key_size = min_size; 4699 sm_max_encryption_key_size = max_size; 4700 } 4701 4702 void sm_set_authentication_requirements(uint8_t auth_req){ 4703 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4704 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4705 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4706 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4707 } 4708 #endif 4709 sm_auth_req = auth_req; 4710 } 4711 4712 void sm_set_io_capabilities(io_capability_t io_capability){ 4713 sm_io_capabilities = io_capability; 4714 } 4715 4716 #ifdef ENABLE_LE_PERIPHERAL 4717 void sm_set_request_security(int enable){ 4718 sm_slave_request_security = enable; 4719 } 4720 #endif 4721 4722 void sm_set_er(sm_key_t er){ 4723 (void)memcpy(sm_persistent_er, er, 16); 4724 } 4725 4726 void sm_set_ir(sm_key_t ir){ 4727 (void)memcpy(sm_persistent_ir, ir, 16); 4728 } 4729 4730 // Testing support only 4731 void sm_test_set_irk(sm_key_t irk){ 4732 (void)memcpy(sm_persistent_irk, irk, 16); 4733 dkg_state = DKG_CALC_DHK; 4734 test_use_fixed_local_irk = true; 4735 } 4736 4737 void sm_test_use_fixed_local_csrk(void){ 4738 test_use_fixed_local_csrk = true; 4739 } 4740 4741 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4742 static void sm_ec_generated(void * arg){ 4743 UNUSED(arg); 4744 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4745 // trigger pairing if pending for ec key 4746 sm_trigger_run(); 4747 } 4748 static void sm_ec_generate_new_key(void){ 4749 log_info("sm: generate new ec key"); 4750 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4751 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4752 } 4753 #endif 4754 4755 #ifdef ENABLE_TESTING_SUPPORT 4756 void sm_test_set_pairing_failure(int reason){ 4757 test_pairing_failure = reason; 4758 } 4759 #endif 4760 4761 static void sm_state_reset() { 4762 #ifdef USE_CMAC_ENGINE 4763 sm_cmac_active = 0; 4764 #endif 4765 dkg_state = DKG_W4_WORKING; 4766 rau_state = RAU_IDLE; 4767 sm_aes128_state = SM_AES128_IDLE; 4768 sm_address_resolution_test = -1; // no private address to resolve yet 4769 sm_address_resolution_ah_calculation_active = 0; 4770 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4771 sm_address_resolution_general_queue = NULL; 4772 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4773 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4774 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4775 #endif 4776 } 4777 4778 void sm_init(void){ 4779 4780 if (sm_initialized) return; 4781 4782 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4783 sm_er_ir_set_default(); 4784 4785 // defaults 4786 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4787 | SM_STK_GENERATION_METHOD_OOB 4788 | SM_STK_GENERATION_METHOD_PASSKEY 4789 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4790 4791 sm_max_encryption_key_size = 16; 4792 sm_min_encryption_key_size = 7; 4793 4794 sm_fixed_passkey_in_display_role = 0xffffffffU; 4795 sm_reconstruct_ltk_without_le_device_db_entry = true; 4796 4797 gap_random_adress_update_period = 15 * 60 * 1000L; 4798 4799 test_use_fixed_local_csrk = false; 4800 4801 // other 4802 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4803 4804 // register for HCI Events from HCI 4805 hci_event_callback_registration.callback = &sm_event_packet_handler; 4806 hci_add_event_handler(&hci_event_callback_registration); 4807 4808 // 4809 btstack_crypto_init(); 4810 4811 // init le_device_db 4812 le_device_db_init(); 4813 4814 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4815 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4816 4817 // state 4818 sm_state_reset(); 4819 4820 sm_initialized = true; 4821 } 4822 4823 void sm_deinit(void){ 4824 sm_initialized = false; 4825 btstack_run_loop_remove_timer(&sm_run_timer); 4826 } 4827 4828 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4829 sm_fixed_passkey_in_display_role = passkey; 4830 } 4831 4832 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4833 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4834 } 4835 4836 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4837 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4838 if (!hci_con) return NULL; 4839 return &hci_con->sm_connection; 4840 } 4841 4842 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4843 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4844 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4845 if (!hci_con) return NULL; 4846 return &hci_con->sm_connection; 4847 } 4848 #endif 4849 4850 // @deprecated: map onto sm_request_pairing 4851 void sm_send_security_request(hci_con_handle_t con_handle){ 4852 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4853 if (!sm_conn) return; 4854 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4855 sm_request_pairing(con_handle); 4856 } 4857 4858 // request pairing 4859 void sm_request_pairing(hci_con_handle_t con_handle){ 4860 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4861 if (!sm_conn) return; // wrong connection 4862 4863 bool have_ltk; 4864 uint8_t ltk[16]; 4865 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4866 if (IS_RESPONDER(sm_conn->sm_role)){ 4867 switch (sm_conn->sm_engine_state){ 4868 case SM_GENERAL_IDLE: 4869 case SM_RESPONDER_IDLE: 4870 switch (sm_conn->sm_irk_lookup_state){ 4871 case IRK_LOOKUP_SUCCEEDED: 4872 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4873 have_ltk = !sm_is_null_key(ltk); 4874 log_info("have ltk %u", have_ltk); 4875 if (have_ltk){ 4876 sm_conn->sm_pairing_requested = 1; 4877 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4878 sm_reencryption_started(sm_conn); 4879 break; 4880 } 4881 /* fall through */ 4882 4883 case IRK_LOOKUP_FAILED: 4884 sm_conn->sm_pairing_requested = 1; 4885 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4886 sm_pairing_started(sm_conn); 4887 break; 4888 default: 4889 log_info("irk lookup pending"); 4890 sm_conn->sm_pairing_requested = 1; 4891 break; 4892 } 4893 break; 4894 default: 4895 break; 4896 } 4897 } else { 4898 // used as a trigger to start central/master/initiator security procedures 4899 switch (sm_conn->sm_engine_state){ 4900 case SM_INITIATOR_CONNECTED: 4901 switch (sm_conn->sm_irk_lookup_state){ 4902 case IRK_LOOKUP_SUCCEEDED: 4903 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4904 have_ltk = !sm_is_null_key(ltk); 4905 log_info("have ltk %u", have_ltk); 4906 if (have_ltk){ 4907 sm_conn->sm_pairing_requested = 1; 4908 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4909 break; 4910 } 4911 /* fall through */ 4912 4913 case IRK_LOOKUP_FAILED: 4914 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4915 break; 4916 default: 4917 log_info("irk lookup pending"); 4918 sm_conn->sm_pairing_requested = 1; 4919 break; 4920 } 4921 break; 4922 case SM_GENERAL_REENCRYPTION_FAILED: 4923 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4924 break; 4925 case SM_GENERAL_IDLE: 4926 sm_conn->sm_pairing_requested = 1; 4927 break; 4928 default: 4929 break; 4930 } 4931 } 4932 sm_trigger_run(); 4933 } 4934 4935 // called by client app on authorization request 4936 void sm_authorization_decline(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 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4940 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4941 } 4942 4943 void sm_authorization_grant(hci_con_handle_t con_handle){ 4944 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4945 if (!sm_conn) return; // wrong connection 4946 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4947 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4948 } 4949 4950 // GAP Bonding API 4951 4952 void sm_bonding_decline(hci_con_handle_t con_handle){ 4953 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4954 if (!sm_conn) return; // wrong connection 4955 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4956 log_info("decline, state %u", sm_conn->sm_engine_state); 4957 switch(sm_conn->sm_engine_state){ 4958 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4959 case SM_SC_W4_USER_RESPONSE: 4960 case SM_SC_W4_CONFIRMATION: 4961 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4962 #endif 4963 case SM_PH1_W4_USER_RESPONSE: 4964 switch (setup->sm_stk_generation_method){ 4965 case PK_RESP_INPUT: 4966 case PK_INIT_INPUT: 4967 case PK_BOTH_INPUT: 4968 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4969 break; 4970 case NUMERIC_COMPARISON: 4971 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4972 break; 4973 case JUST_WORKS: 4974 case OOB: 4975 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4976 break; 4977 default: 4978 btstack_assert(false); 4979 break; 4980 } 4981 break; 4982 default: 4983 break; 4984 } 4985 sm_trigger_run(); 4986 } 4987 4988 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4989 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4990 if (!sm_conn) return; // wrong connection 4991 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4992 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4993 if (setup->sm_use_secure_connections){ 4994 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4995 } else { 4996 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); 4997 } 4998 } 4999 5000 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5001 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5002 sm_sc_prepare_dhkey_check(sm_conn); 5003 } 5004 #endif 5005 5006 sm_trigger_run(); 5007 } 5008 5009 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5010 // for now, it's the same 5011 sm_just_works_confirm(con_handle); 5012 } 5013 5014 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5015 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5016 if (!sm_conn) return; // wrong connection 5017 sm_reset_tk(); 5018 big_endian_store_32(setup->sm_tk, 12, passkey); 5019 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5020 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5021 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); 5022 } 5023 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5024 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5025 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5026 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5027 sm_sc_start_calculating_local_confirm(sm_conn); 5028 } 5029 #endif 5030 sm_trigger_run(); 5031 } 5032 5033 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5034 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5035 if (!sm_conn) return; // wrong connection 5036 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5037 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5038 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5039 switch (action){ 5040 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5041 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5042 flags |= (1u << action); 5043 break; 5044 case SM_KEYPRESS_PASSKEY_CLEARED: 5045 // clear counter, keypress & erased flags + set passkey cleared 5046 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5047 break; 5048 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5049 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 5050 // erase actions queued 5051 num_actions--; 5052 if (num_actions == 0u){ 5053 // clear counter, keypress & erased flags 5054 flags &= 0x19u; 5055 } 5056 break; 5057 } 5058 num_actions++; 5059 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5060 break; 5061 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5062 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5063 // enter actions queued 5064 num_actions--; 5065 if (num_actions == 0u){ 5066 // clear counter, keypress & erased flags 5067 flags &= 0x19u; 5068 } 5069 break; 5070 } 5071 num_actions++; 5072 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5073 break; 5074 default: 5075 break; 5076 } 5077 setup->sm_keypress_notification = (num_actions << 5) | flags; 5078 sm_trigger_run(); 5079 } 5080 5081 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5082 static void sm_handle_random_result_oob(void * arg){ 5083 UNUSED(arg); 5084 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5085 sm_trigger_run(); 5086 } 5087 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5088 5089 static btstack_crypto_random_t sm_crypto_random_oob_request; 5090 5091 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5092 sm_sc_oob_callback = callback; 5093 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5094 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5095 return 0; 5096 } 5097 #endif 5098 5099 /** 5100 * @brief Get Identity Resolving state 5101 * @param con_handle 5102 * @return irk_lookup_state_t 5103 */ 5104 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5105 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5106 if (!sm_conn) return IRK_LOOKUP_IDLE; 5107 return sm_conn->sm_irk_lookup_state; 5108 } 5109 5110 /** 5111 * @brief Identify device in LE Device DB 5112 * @param handle 5113 * @return index from le_device_db or -1 if not found/identified 5114 */ 5115 int sm_le_device_index(hci_con_handle_t con_handle ){ 5116 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5117 if (!sm_conn) return -1; 5118 return sm_conn->sm_le_db_index; 5119 } 5120 5121 static int gap_random_address_type_requires_updates(void){ 5122 switch (gap_random_adress_type){ 5123 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5124 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5125 return 0; 5126 default: 5127 return 1; 5128 } 5129 } 5130 5131 static uint8_t own_address_type(void){ 5132 switch (gap_random_adress_type){ 5133 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5134 return BD_ADDR_TYPE_LE_PUBLIC; 5135 default: 5136 return BD_ADDR_TYPE_LE_RANDOM; 5137 } 5138 } 5139 5140 // GAP LE API 5141 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5142 gap_random_address_update_stop(); 5143 gap_random_adress_type = random_address_type; 5144 hci_le_set_own_address_type(own_address_type()); 5145 if (!gap_random_address_type_requires_updates()) return; 5146 gap_random_address_update_start(); 5147 gap_random_address_trigger(); 5148 } 5149 5150 gap_random_address_type_t gap_random_address_get_mode(void){ 5151 return gap_random_adress_type; 5152 } 5153 5154 void gap_random_address_set_update_period(int period_ms){ 5155 gap_random_adress_update_period = period_ms; 5156 if (!gap_random_address_type_requires_updates()) return; 5157 gap_random_address_update_stop(); 5158 gap_random_address_update_start(); 5159 } 5160 5161 void gap_random_address_set(const bd_addr_t addr){ 5162 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5163 (void)memcpy(sm_random_address, addr, 6); 5164 hci_le_random_address_set(addr); 5165 } 5166 5167 #ifdef ENABLE_LE_PERIPHERAL 5168 /* 5169 * @brief Set Advertisement Paramters 5170 * @param adv_int_min 5171 * @param adv_int_max 5172 * @param adv_type 5173 * @param direct_address_type 5174 * @param direct_address 5175 * @param channel_map 5176 * @param filter_policy 5177 * 5178 * @note own_address_type is used from gap_random_address_set_mode 5179 */ 5180 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5181 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5182 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5183 direct_address_typ, direct_address, channel_map, filter_policy); 5184 } 5185 #endif 5186 5187 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5188 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5189 // wrong connection 5190 if (!sm_conn) return 0; 5191 // already encrypted 5192 if (sm_conn->sm_connection_encrypted) return 0; 5193 // irk status? 5194 switch(sm_conn->sm_irk_lookup_state){ 5195 case IRK_LOOKUP_FAILED: 5196 // done, cannot setup encryption 5197 return 0; 5198 case IRK_LOOKUP_SUCCEEDED: 5199 break; 5200 default: 5201 // IR Lookup pending 5202 return 1; 5203 } 5204 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5205 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5206 if (sm_conn->sm_role){ 5207 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5208 } else { 5209 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5210 } 5211 } 5212 5213 void sm_set_secure_connections_only_mode(bool enable){ 5214 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5215 sm_sc_only_mode = enable; 5216 #else 5217 // SC Only mode not possible without support for SC 5218 btstack_assert(enable == false); 5219 #endif 5220 } 5221 5222 const uint8_t * gap_get_persistent_irk(void){ 5223 return sm_persistent_irk; 5224 } 5225 5226 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5227 uint16_t i; 5228 for (i=0; i < le_device_db_max_count(); i++){ 5229 bd_addr_t entry_address; 5230 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5231 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5232 // skip unused entries 5233 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5234 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5235 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 5236 hci_remove_le_device_db_entry_from_resolving_list(i); 5237 #endif 5238 le_device_db_remove(i); 5239 break; 5240 } 5241 } 5242 } 5243