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) == HCI_ROLE_SLAVE) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && ((role) == HCI_ROLE_SLAVE)) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || ((role) == HCI_ROLE_SLAVE)) 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 bool 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 #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY 210 static bool sm_sc_debug_keys_enabled; 211 #endif 212 #endif 213 214 215 static bool sm_persistent_keys_random_active; 216 static const btstack_tlv_t * sm_tlv_impl; 217 static void * sm_tlv_context; 218 219 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 220 static sm_key_t sm_persistent_er; 221 static sm_key_t sm_persistent_ir; 222 223 // derived from sm_persistent_ir 224 static sm_key_t sm_persistent_dhk; 225 static sm_key_t sm_persistent_irk; 226 static derived_key_generation_t dkg_state; 227 228 // derived from sm_persistent_er 229 // .. 230 231 // random address update 232 static random_address_update_t rau_state; 233 static bd_addr_t sm_random_address; 234 235 #ifdef USE_CMAC_ENGINE 236 // CMAC Calculation: General 237 static btstack_crypto_aes128_cmac_t sm_cmac_request; 238 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 239 static uint8_t sm_cmac_active; 240 static uint8_t sm_cmac_hash[16]; 241 #endif 242 243 // CMAC for ATT Signed Writes 244 #ifdef ENABLE_LE_SIGNED_WRITE 245 static uint16_t sm_cmac_signed_write_message_len; 246 static uint8_t sm_cmac_signed_write_header[3]; 247 static const uint8_t * sm_cmac_signed_write_message; 248 static uint8_t sm_cmac_signed_write_sign_counter[4]; 249 #endif 250 251 // CMAC for Secure Connection functions 252 #ifdef ENABLE_LE_SECURE_CONNECTIONS 253 static sm_connection_t * sm_cmac_connection; 254 static uint8_t sm_cmac_sc_buffer[80]; 255 #endif 256 257 // resolvable private address lookup / CSRK calculation 258 static int sm_address_resolution_test; 259 static uint8_t sm_address_resolution_addr_type; 260 static bd_addr_t sm_address_resolution_address; 261 static void * sm_address_resolution_context; 262 static address_resolution_mode_t sm_address_resolution_mode; 263 static btstack_linked_list_t sm_address_resolution_general_queue; 264 265 // aes128 crypto engine. 266 static sm_aes128_state_t sm_aes128_state; 267 268 // crypto 269 static btstack_crypto_random_t sm_crypto_random_request; 270 static btstack_crypto_aes128_t sm_crypto_aes128_request; 271 #ifdef ENABLE_LE_SECURE_CONNECTIONS 272 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 273 #endif 274 275 // temp storage for random data 276 static uint8_t sm_random_data[8]; 277 static uint8_t sm_aes128_key[16]; 278 static uint8_t sm_aes128_plaintext[16]; 279 static uint8_t sm_aes128_ciphertext[16]; 280 281 // to receive events 282 static btstack_packet_callback_registration_t hci_event_callback_registration; 283 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 284 static btstack_packet_callback_registration_t l2cap_event_callback_registration; 285 #endif 286 287 /* to dispatch sm event */ 288 static btstack_linked_list_t sm_event_handlers; 289 290 /* to schedule calls to sm_run */ 291 static btstack_timer_source_t sm_run_timer; 292 293 // LE Secure Connections 294 #ifdef ENABLE_LE_SECURE_CONNECTIONS 295 static ec_key_generation_state_t ec_key_generation_state; 296 static uint8_t ec_q[64]; 297 #endif 298 299 // 300 // Volume 3, Part H, Chapter 24 301 // "Security shall be initiated by the Security Manager in the device in the master role. 302 // The device in the slave role shall be the responding device." 303 // -> master := initiator, slave := responder 304 // 305 306 // data needed for security setup 307 typedef struct sm_setup_context { 308 309 btstack_timer_source_t sm_timeout; 310 311 // user response, (Phase 1 and/or 2) 312 uint8_t sm_user_response; 313 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 314 315 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 316 uint8_t sm_key_distribution_send_set; 317 uint8_t sm_key_distribution_sent_set; 318 uint8_t sm_key_distribution_expected_set; 319 uint8_t sm_key_distribution_received_set; 320 321 // Phase 2 (Pairing over SMP) 322 stk_generation_method_t sm_stk_generation_method; 323 sm_key_t sm_tk; 324 uint8_t sm_have_oob_data; 325 bool sm_use_secure_connections; 326 327 sm_key_t sm_c1_t3_value; // c1 calculation 328 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 329 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 330 sm_key_t sm_local_random; 331 sm_key_t sm_local_confirm; 332 sm_key_t sm_peer_random; 333 sm_key_t sm_peer_confirm; 334 uint8_t sm_m_addr_type; // address and type can be removed 335 uint8_t sm_s_addr_type; // '' 336 bd_addr_t sm_m_address; // '' 337 bd_addr_t sm_s_address; // '' 338 sm_key_t sm_ltk; 339 340 uint8_t sm_state_vars; 341 #ifdef ENABLE_LE_SECURE_CONNECTIONS 342 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 343 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 344 sm_key_t sm_local_nonce; // might be combined with sm_local_random 345 uint8_t sm_dhkey[32]; 346 sm_key_t sm_peer_dhkey_check; 347 sm_key_t sm_local_dhkey_check; 348 sm_key_t sm_ra; 349 sm_key_t sm_rb; 350 sm_key_t sm_t; // used for f5 and h6 351 sm_key_t sm_mackey; 352 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 353 #endif 354 355 // Phase 3 356 357 // key distribution, we generate 358 uint16_t sm_local_y; 359 uint16_t sm_local_div; 360 uint16_t sm_local_ediv; 361 uint8_t sm_local_rand[8]; 362 sm_key_t sm_local_ltk; 363 sm_key_t sm_local_csrk; 364 sm_key_t sm_local_irk; 365 // sm_local_address/addr_type not needed 366 367 // key distribution, received from peer 368 uint16_t sm_peer_y; 369 uint16_t sm_peer_div; 370 uint16_t sm_peer_ediv; 371 uint8_t sm_peer_rand[8]; 372 sm_key_t sm_peer_ltk; 373 sm_key_t sm_peer_irk; 374 sm_key_t sm_peer_csrk; 375 uint8_t sm_peer_addr_type; 376 bd_addr_t sm_peer_address; 377 #ifdef ENABLE_LE_SIGNED_WRITE 378 int sm_le_device_index; 379 #endif 380 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 381 link_key_t sm_link_key; 382 link_key_type_t sm_link_key_type; 383 #endif 384 } sm_setup_context_t; 385 386 // 387 static sm_setup_context_t the_setup; 388 static sm_setup_context_t * setup = &the_setup; 389 390 // active connection - the one for which the_setup is used for 391 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 392 393 // @return 1 if oob data is available 394 // stores oob data in provided 16 byte buffer if not null 395 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 396 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); 397 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 398 399 static void sm_run(void); 400 static void sm_state_reset(void); 401 static void sm_done_for_handle(hci_con_handle_t con_handle); 402 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 403 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk); 404 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 405 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 406 #endif 407 static inline int sm_calc_actual_encryption_key_size(int other); 408 static int sm_validate_stk_generation_method(void); 409 static void sm_handle_encryption_result_address_resolution(void *arg); 410 static void sm_handle_encryption_result_dkg_dhk(void *arg); 411 static void sm_handle_encryption_result_dkg_irk(void *arg); 412 static void sm_handle_encryption_result_enc_a(void *arg); 413 static void sm_handle_encryption_result_enc_b(void *arg); 414 static void sm_handle_encryption_result_enc_c(void *arg); 415 static void sm_handle_encryption_result_enc_csrk(void *arg); 416 static void sm_handle_encryption_result_enc_d(void * arg); 417 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 418 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 419 #ifdef ENABLE_LE_PERIPHERAL 420 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 421 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 422 #endif 423 static void sm_handle_encryption_result_enc_stk(void *arg); 424 static void sm_handle_encryption_result_rau(void *arg); 425 static void sm_handle_random_result_ph2_tk(void * arg); 426 static void sm_handle_random_result_rau(void * arg); 427 #ifdef ENABLE_LE_SECURE_CONNECTIONS 428 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)); 429 static void sm_ec_generate_new_key(void); 430 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 431 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 432 static bool sm_passkey_entry(stk_generation_method_t method); 433 #endif 434 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 435 436 static void log_info_hex16(const char * name, uint16_t value){ 437 log_info("%-6s 0x%04x", name, value); 438 } 439 440 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 441 // return packet[0]; 442 // } 443 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 444 return packet[1]; 445 } 446 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 447 return packet[2]; 448 } 449 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 450 return packet[3]; 451 } 452 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 453 return packet[4]; 454 } 455 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 456 return packet[5]; 457 } 458 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 459 return packet[6]; 460 } 461 462 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 463 packet[0] = code; 464 } 465 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 466 packet[1] = io_capability; 467 } 468 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 469 packet[2] = oob_data_flag; 470 } 471 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 472 packet[3] = auth_req; 473 } 474 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 475 packet[4] = max_encryption_key_size; 476 } 477 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 478 packet[5] = initiator_key_distribution; 479 } 480 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 481 packet[6] = responder_key_distribution; 482 } 483 484 static bool sm_is_null_random(uint8_t random[8]){ 485 return btstack_is_null(random, 8); 486 } 487 488 static bool sm_is_null_key(uint8_t * key){ 489 return btstack_is_null(key, 16); 490 } 491 492 #ifdef ENABLE_LE_SECURE_CONNECTIONS 493 static bool sm_is_ff(const uint8_t * buffer, uint16_t size){ 494 uint16_t i; 495 for (i=0; i < size ; i++){ 496 if (buffer[i] != 0xff) { 497 return false; 498 } 499 } 500 return true; 501 } 502 #endif 503 504 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 505 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 506 UNUSED(ts); 507 sm_run(); 508 } 509 static void sm_trigger_run(void){ 510 if (!sm_initialized) return; 511 (void)btstack_run_loop_remove_timer(&sm_run_timer); 512 btstack_run_loop_set_timer(&sm_run_timer, 0); 513 btstack_run_loop_add_timer(&sm_run_timer); 514 } 515 516 // Key utils 517 static void sm_reset_tk(void){ 518 int i; 519 for (i=0;i<16;i++){ 520 setup->sm_tk[i] = 0; 521 } 522 } 523 524 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 525 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 526 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 527 int i; 528 for (i = max_encryption_size ; i < 16 ; i++){ 529 key[15-i] = 0; 530 } 531 } 532 533 // ER / IR checks 534 static void sm_er_ir_set_default(void){ 535 int i; 536 for (i=0;i<16;i++){ 537 sm_persistent_er[i] = 0x30 + i; 538 sm_persistent_ir[i] = 0x90 + i; 539 } 540 } 541 542 static bool sm_er_is_default(void){ 543 int i; 544 for (i=0;i<16;i++){ 545 if (sm_persistent_er[i] != (0x30+i)) return true; 546 } 547 return false; 548 } 549 550 static bool sm_ir_is_default(void){ 551 int i; 552 for (i=0;i<16;i++){ 553 if (sm_persistent_ir[i] != (0x90+i)) return true; 554 } 555 return false; 556 } 557 558 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 559 UNUSED(channel); 560 561 // log event 562 hci_dump_packet(packet_type, 1, packet, size); 563 // dispatch to all event handlers 564 btstack_linked_list_iterator_t it; 565 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 566 while (btstack_linked_list_iterator_has_next(&it)){ 567 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 568 entry->callback(packet_type, 0, packet, size); 569 } 570 } 571 572 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){ 573 event[0] = type; 574 event[1] = event_size - 2; 575 little_endian_store_16(event, 2, con_handle); 576 event[4] = addr_type; 577 reverse_bd_addr(address, &event[5]); 578 } 579 580 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 581 uint8_t event[11]; 582 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 583 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 584 } 585 586 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){ 587 // fetch addr and addr type from db, only called for valid entries 588 bd_addr_t identity_address; 589 int identity_address_type; 590 le_device_db_info(index, &identity_address_type, identity_address, NULL); 591 592 uint8_t event[20]; 593 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 594 event[11] = identity_address_type; 595 reverse_bd_addr(identity_address, &event[12]); 596 little_endian_store_16(event, 18, index); 597 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 598 } 599 600 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){ 601 uint8_t event[12]; 602 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 603 event[11] = status; 604 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 605 } 606 607 608 static void sm_reencryption_started(sm_connection_t * sm_conn){ 609 610 if (sm_conn->sm_reencryption_active) return; 611 612 sm_conn->sm_reencryption_active = true; 613 614 int identity_addr_type; 615 bd_addr_t identity_addr; 616 if (sm_conn->sm_le_db_index >= 0){ 617 // fetch addr and addr type from db, only called for valid entries 618 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 619 } else { 620 // for legacy pairing with LTK re-construction, use current peer addr 621 identity_addr_type = sm_conn->sm_peer_addr_type; 622 // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy 623 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 624 } 625 626 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 627 } 628 629 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 630 631 if (!sm_conn->sm_reencryption_active) return; 632 633 sm_conn->sm_reencryption_active = false; 634 635 int identity_addr_type; 636 bd_addr_t identity_addr; 637 if (sm_conn->sm_le_db_index >= 0){ 638 // fetch addr and addr type from db, only called for valid entries 639 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 640 } else { 641 // for legacy pairing with LTK re-construction, use current peer addr 642 identity_addr_type = sm_conn->sm_peer_addr_type; 643 // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy 644 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 645 } 646 647 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 648 } 649 650 static void sm_pairing_started(sm_connection_t * sm_conn){ 651 652 if (sm_conn->sm_pairing_active) return; 653 654 sm_conn->sm_pairing_active = true; 655 656 uint8_t event[11]; 657 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 658 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 659 } 660 661 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 662 663 if (!sm_conn->sm_pairing_active) return; 664 665 sm_conn->sm_pairing_active = false; 666 667 uint8_t event[13]; 668 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 669 event[11] = status; 670 event[12] = reason; 671 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 672 } 673 674 // SMP Timeout implementation 675 676 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 677 // the Security Manager Timer shall be reset and started. 678 // 679 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 680 // 681 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 682 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 683 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 684 // established. 685 686 static void sm_timeout_handler(btstack_timer_source_t * timer){ 687 log_info("SM timeout"); 688 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 689 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 690 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 691 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 692 sm_done_for_handle(sm_conn->sm_handle); 693 694 // trigger handling of next ready connection 695 sm_run(); 696 } 697 static void sm_timeout_start(sm_connection_t * sm_conn){ 698 btstack_run_loop_remove_timer(&setup->sm_timeout); 699 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 700 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 701 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 702 btstack_run_loop_add_timer(&setup->sm_timeout); 703 } 704 static void sm_timeout_stop(void){ 705 btstack_run_loop_remove_timer(&setup->sm_timeout); 706 } 707 static void sm_timeout_reset(sm_connection_t * sm_conn){ 708 sm_timeout_stop(); 709 sm_timeout_start(sm_conn); 710 } 711 712 // end of sm timeout 713 714 // GAP Random Address updates 715 static gap_random_address_type_t gap_random_adress_type; 716 static btstack_timer_source_t gap_random_address_update_timer; 717 static uint32_t gap_random_adress_update_period; 718 719 static void gap_random_address_trigger(void){ 720 log_info("gap_random_address_trigger, state %u", rau_state); 721 if (rau_state != RAU_IDLE) return; 722 rau_state = RAU_GET_RANDOM; 723 sm_trigger_run(); 724 } 725 726 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 727 UNUSED(timer); 728 729 log_info("GAP Random Address Update due"); 730 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 731 btstack_run_loop_add_timer(&gap_random_address_update_timer); 732 gap_random_address_trigger(); 733 } 734 735 static void gap_random_address_update_start(void){ 736 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 737 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 738 btstack_run_loop_add_timer(&gap_random_address_update_timer); 739 } 740 741 static void gap_random_address_update_stop(void){ 742 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 743 } 744 745 // ah(k,r) helper 746 // r = padding || r 747 // r - 24 bit value 748 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 749 // r'= padding || r 750 memset(r_prime, 0, 16); 751 (void)memcpy(&r_prime[13], r, 3); 752 } 753 754 // d1 helper 755 // d' = padding || r || d 756 // d,r - 16 bit values 757 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 758 // d'= padding || r || d 759 memset(d1_prime, 0, 16); 760 big_endian_store_16(d1_prime, 12, r); 761 big_endian_store_16(d1_prime, 14, d); 762 } 763 764 // calculate arguments for first AES128 operation in C1 function 765 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){ 766 767 // p1 = pres || preq || rat’ || iat’ 768 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 769 // cant octet of pres becomes the most significant octet of p1. 770 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 771 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 772 // p1 is 0x05000800000302070710000001010001." 773 774 sm_key_t p1; 775 reverse_56(pres, &p1[0]); 776 reverse_56(preq, &p1[7]); 777 p1[14] = rat; 778 p1[15] = iat; 779 log_info_key("p1", p1); 780 log_info_key("r", r); 781 782 // t1 = r xor p1 783 int i; 784 for (i=0;i<16;i++){ 785 t1[i] = r[i] ^ p1[i]; 786 } 787 log_info_key("t1", t1); 788 } 789 790 // calculate arguments for second AES128 operation in C1 function 791 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 792 // p2 = padding || ia || ra 793 // "The least significant octet of ra becomes the least significant octet of p2 and 794 // the most significant octet of padding becomes the most significant octet of p2. 795 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 796 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 797 798 sm_key_t p2; 799 // cppcheck-suppress uninitvar ; p2 is reported as uninitialized 800 memset(p2, 0, 16); 801 (void)memcpy(&p2[4], ia, 6); 802 (void)memcpy(&p2[10], ra, 6); 803 log_info_key("p2", p2); 804 805 // c1 = e(k, t2_xor_p2) 806 int i; 807 for (i=0;i<16;i++){ 808 t3[i] = t2[i] ^ p2[i]; 809 } 810 log_info_key("t3", t3); 811 } 812 813 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 814 log_info_key("r1", r1); 815 log_info_key("r2", r2); 816 (void)memcpy(&r_prime[8], &r2[8], 8); 817 (void)memcpy(&r_prime[0], &r1[8], 8); 818 } 819 820 821 // decide on stk generation based on 822 // - pairing request 823 // - io capabilities 824 // - OOB data availability 825 static void sm_setup_tk(void){ 826 827 // horizontal: initiator capabilities 828 // vertial: responder capabilities 829 static const stk_generation_method_t stk_generation_method [5] [5] = { 830 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 831 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 832 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 833 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 834 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 835 }; 836 837 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 838 #ifdef ENABLE_LE_SECURE_CONNECTIONS 839 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 840 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 841 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 842 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 843 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 844 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 845 }; 846 #endif 847 848 // default: just works 849 setup->sm_stk_generation_method = JUST_WORKS; 850 851 #ifdef ENABLE_LE_SECURE_CONNECTIONS 852 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 853 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 854 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 855 #else 856 setup->sm_use_secure_connections = false; 857 #endif 858 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 859 860 861 // decide if OOB will be used based on SC vs. Legacy and oob flags 862 bool use_oob; 863 if (setup->sm_use_secure_connections){ 864 // In LE Secure Connections pairing, the out of band method is used if at least 865 // one device has the peer device's out of band authentication data available. 866 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; 867 } else { 868 // In LE legacy pairing, the out of band method is used if both the devices have 869 // the other device's out of band authentication data available. 870 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; 871 } 872 if (use_oob){ 873 log_info("SM: have OOB data"); 874 log_info_key("OOB", setup->sm_tk); 875 setup->sm_stk_generation_method = OOB; 876 return; 877 } 878 879 // If both devices have not set the MITM option in the Authentication Requirements 880 // Flags, then the IO capabilities shall be ignored and the Just Works association 881 // model shall be used. 882 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 883 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 884 log_info("SM: MITM not required by both -> JUST WORKS"); 885 return; 886 } 887 888 // Reset TK as it has been setup in sm_init_setup 889 sm_reset_tk(); 890 891 // Also use just works if unknown io capabilites 892 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)){ 893 return; 894 } 895 896 // Otherwise the IO capabilities of the devices shall be used to determine the 897 // pairing method as defined in Table 2.4. 898 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 899 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 900 901 #ifdef ENABLE_LE_SECURE_CONNECTIONS 902 // table not define by default 903 if (setup->sm_use_secure_connections){ 904 generation_method = stk_generation_method_with_secure_connection; 905 } 906 #endif 907 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)]; 908 909 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 910 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); 911 } 912 913 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 914 int flags = 0; 915 if ((key_set & SM_KEYDIST_ENC_KEY) != 0u){ 916 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 917 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 918 } 919 if ((key_set & SM_KEYDIST_ID_KEY) != 0u){ 920 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 921 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 922 } 923 if ((key_set & SM_KEYDIST_SIGN) != 0u){ 924 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 925 } 926 return flags; 927 } 928 929 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 930 setup->sm_key_distribution_received_set = 0; 931 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 932 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 933 setup->sm_key_distribution_sent_set = 0; 934 #ifdef ENABLE_LE_SIGNED_WRITE 935 setup->sm_le_device_index = -1; 936 #endif 937 } 938 939 // CSRK Key Lookup 940 941 942 static bool sm_address_resolution_idle(void){ 943 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 944 } 945 946 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){ 947 (void)memcpy(sm_address_resolution_address, addr, 6); 948 sm_address_resolution_addr_type = addr_type; 949 sm_address_resolution_test = 0; 950 sm_address_resolution_mode = mode; 951 sm_address_resolution_context = context; 952 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 953 } 954 955 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 956 // check if already in list 957 btstack_linked_list_iterator_t it; 958 sm_lookup_entry_t * entry; 959 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 960 while(btstack_linked_list_iterator_has_next(&it)){ 961 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 962 if (entry->address_type != address_type) continue; 963 if (memcmp(entry->address, address, 6) != 0) continue; 964 // already in list 965 return BTSTACK_BUSY; 966 } 967 entry = btstack_memory_sm_lookup_entry_get(); 968 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 969 entry->address_type = (bd_addr_type_t) address_type; 970 (void)memcpy(entry->address, address, 6); 971 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 972 sm_trigger_run(); 973 return 0; 974 } 975 976 // CMAC calculation using AES Engineq 977 #ifdef USE_CMAC_ENGINE 978 979 static void sm_cmac_done_trampoline(void * arg){ 980 UNUSED(arg); 981 sm_cmac_active = 0; 982 (*sm_cmac_done_callback)(sm_cmac_hash); 983 sm_trigger_run(); 984 } 985 986 int sm_cmac_ready(void){ 987 return sm_cmac_active == 0u; 988 } 989 #endif 990 991 #ifdef ENABLE_LE_SECURE_CONNECTIONS 992 // generic cmac calculation 993 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)){ 994 sm_cmac_active = 1; 995 sm_cmac_done_callback = done_callback; 996 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 997 } 998 #endif 999 1000 // cmac for ATT Message signing 1001 #ifdef ENABLE_LE_SIGNED_WRITE 1002 1003 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)){ 1004 sm_cmac_active = 1; 1005 sm_cmac_done_callback = done_callback; 1006 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 1007 } 1008 1009 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1010 if (offset >= sm_cmac_signed_write_message_len) { 1011 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1012 return 0; 1013 } 1014 1015 offset = sm_cmac_signed_write_message_len - 1 - offset; 1016 1017 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1018 if (offset < 3){ 1019 return sm_cmac_signed_write_header[offset]; 1020 } 1021 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1022 if (offset < actual_message_len_incl_header){ 1023 return sm_cmac_signed_write_message[offset - 3]; 1024 } 1025 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1026 } 1027 1028 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)){ 1029 // ATT Message Signing 1030 sm_cmac_signed_write_header[0] = opcode; 1031 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1032 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1033 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1034 sm_cmac_signed_write_message = message; 1035 sm_cmac_signed_write_message_len = total_message_len; 1036 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1037 } 1038 #endif 1039 1040 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1041 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1042 uint8_t event[12]; 1043 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1044 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1045 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1046 } 1047 1048 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn, uint8_t event_type){ 1049 uint8_t event[16]; 1050 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1051 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, 1052 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1053 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1054 little_endian_store_32(event, 12, passkey); 1055 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1056 } 1057 1058 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1059 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1060 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1061 sm_conn->sm_pairing_active = true; 1062 switch (setup->sm_stk_generation_method){ 1063 case PK_RESP_INPUT: 1064 if (IS_RESPONDER(sm_conn->sm_role)){ 1065 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1066 } else { 1067 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); 1068 } 1069 break; 1070 case PK_INIT_INPUT: 1071 if (IS_RESPONDER(sm_conn->sm_role)){ 1072 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); 1073 } else { 1074 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1075 } 1076 break; 1077 case PK_BOTH_INPUT: 1078 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1079 break; 1080 case NUMERIC_COMPARISON: 1081 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1082 break; 1083 case JUST_WORKS: 1084 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1085 break; 1086 case OOB: 1087 // client already provided OOB data, let's skip notification. 1088 break; 1089 default: 1090 btstack_assert(false); 1091 break; 1092 } 1093 } 1094 1095 static bool sm_key_distribution_all_received(void) { 1096 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); 1097 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1098 } 1099 1100 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1101 if (sm_active_connection_handle == con_handle){ 1102 sm_timeout_stop(); 1103 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1104 log_info("sm: connection 0x%x released setup context", con_handle); 1105 1106 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1107 // generate new ec key after each pairing (that used it) 1108 if (setup->sm_use_secure_connections){ 1109 sm_ec_generate_new_key(); 1110 } 1111 #endif 1112 } 1113 } 1114 1115 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1116 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1117 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1118 sm_done_for_handle(connection->sm_handle); 1119 } 1120 1121 static int sm_key_distribution_flags_for_auth_req(void){ 1122 1123 int flags = SM_KEYDIST_ID_KEY; 1124 if ((sm_auth_req & SM_AUTHREQ_BONDING) != 0u){ 1125 // encryption and signing information only if bonding requested 1126 flags |= SM_KEYDIST_ENC_KEY; 1127 #ifdef ENABLE_LE_SIGNED_WRITE 1128 flags |= SM_KEYDIST_SIGN; 1129 #endif 1130 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1131 // LinkKey for CTKD requires SC and BR/EDR Support 1132 if (hci_classic_supported() && ((sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION) != 0)){ 1133 flags |= SM_KEYDIST_LINK_KEY; 1134 } 1135 #endif 1136 } 1137 return flags; 1138 } 1139 1140 static void sm_reset_setup(void){ 1141 // fill in sm setup 1142 setup->sm_state_vars = 0; 1143 setup->sm_keypress_notification = 0; 1144 setup->sm_have_oob_data = 0; 1145 sm_reset_tk(); 1146 } 1147 1148 static void sm_init_setup(sm_connection_t * sm_conn){ 1149 // fill in sm setup 1150 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1151 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1152 1153 // query client for Legacy Pairing OOB data 1154 if (sm_get_oob_data != NULL) { 1155 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1156 } 1157 1158 // if available and SC supported, also ask for SC OOB Data 1159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1160 memset(setup->sm_ra, 0, 16); 1161 memset(setup->sm_rb, 0, 16); 1162 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1163 if (sm_get_sc_oob_data != NULL){ 1164 if (IS_RESPONDER(sm_conn->sm_role)){ 1165 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1166 sm_conn->sm_peer_addr_type, 1167 sm_conn->sm_peer_address, 1168 setup->sm_peer_confirm, 1169 setup->sm_ra); 1170 } else { 1171 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1172 sm_conn->sm_peer_addr_type, 1173 sm_conn->sm_peer_address, 1174 setup->sm_peer_confirm, 1175 setup->sm_rb); 1176 } 1177 } else { 1178 setup->sm_have_oob_data = 0; 1179 } 1180 } 1181 #endif 1182 1183 sm_pairing_packet_t * local_packet; 1184 if (IS_RESPONDER(sm_conn->sm_role)){ 1185 // slave 1186 local_packet = &setup->sm_s_pres; 1187 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1188 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1189 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1190 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1191 } else { 1192 // master 1193 local_packet = &setup->sm_m_preq; 1194 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1195 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1196 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1197 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1198 1199 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1200 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1201 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1202 } 1203 1204 log_info("our address %s type %u", bd_addr_to_str(sm_conn->sm_own_address), sm_conn->sm_own_addr_type); 1205 log_info("peer address %s type %u", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); 1206 1207 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1208 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1209 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1210 // enable SC for SC only mode 1211 if (sm_sc_only_mode){ 1212 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1213 max_encryption_key_size = 16; 1214 } 1215 #endif 1216 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1217 // set CT2 if SC + Bonding + CTKD 1218 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1219 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1220 auth_req |= SM_AUTHREQ_CT2; 1221 } 1222 #endif 1223 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1224 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1225 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1226 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1227 } 1228 1229 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1230 1231 sm_pairing_packet_t * remote_packet; 1232 uint8_t keys_to_send; 1233 uint8_t keys_to_receive; 1234 if (IS_RESPONDER(sm_conn->sm_role)){ 1235 // slave / responder 1236 remote_packet = &setup->sm_m_preq; 1237 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1238 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1239 } else { 1240 // master / initiator 1241 remote_packet = &setup->sm_s_pres; 1242 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1243 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1244 } 1245 1246 // check key size 1247 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1248 // SC Only mandates 128 bit key size 1249 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1250 return SM_REASON_ENCRYPTION_KEY_SIZE; 1251 } 1252 #endif 1253 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1254 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1255 1256 // decide on STK generation method / SC 1257 sm_setup_tk(); 1258 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1259 1260 // check if STK generation method is acceptable by client 1261 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1262 1263 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1264 // Check LE SC Only mode 1265 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1266 log_info("SC Only mode active but SC not possible"); 1267 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1268 } 1269 1270 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1271 if (setup->sm_use_secure_connections){ 1272 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1273 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1274 } 1275 #endif 1276 1277 // identical to responder 1278 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1279 1280 // JUST WORKS doens't provide authentication 1281 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1282 1283 return 0; 1284 } 1285 1286 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1287 1288 // cache and reset context 1289 int matched_device_id = sm_address_resolution_test; 1290 address_resolution_mode_t mode = sm_address_resolution_mode; 1291 void * context = sm_address_resolution_context; 1292 1293 // reset context 1294 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1295 sm_address_resolution_context = NULL; 1296 sm_address_resolution_test = -1; 1297 1298 hci_con_handle_t con_handle = HCI_CON_HANDLE_INVALID; 1299 sm_connection_t * sm_connection; 1300 sm_key_t ltk; 1301 bool have_ltk; 1302 int authenticated; 1303 #ifdef ENABLE_LE_CENTRAL 1304 bool trigger_pairing; 1305 #endif 1306 1307 switch (mode){ 1308 case ADDRESS_RESOLUTION_GENERAL: 1309 break; 1310 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1311 sm_connection = (sm_connection_t *) context; 1312 con_handle = sm_connection->sm_handle; 1313 1314 // have ltk -> start encryption / send security request 1315 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1316 // "When a bond has been created between two devices, any reconnection should result in the local device 1317 // enabling or requesting encryption with the remote device before initiating any service request." 1318 1319 switch (event){ 1320 case ADDRESS_RESOLUTION_SUCCEEDED: 1321 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1322 sm_connection->sm_le_db_index = matched_device_id; 1323 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1324 1325 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); 1326 have_ltk = !sm_is_null_key(ltk); 1327 1328 if (IS_RESPONDER(sm_connection->sm_role)) { 1329 #ifdef ENABLE_LE_PERIPHERAL 1330 // IRK required before, continue 1331 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1332 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1333 break; 1334 } 1335 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1336 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1337 break; 1338 } 1339 bool trigger_security_request = sm_connection->sm_pairing_requested || sm_slave_request_security; 1340 sm_connection->sm_pairing_requested = false; 1341 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1342 // trigger security request for Proactive Authentication if LTK available 1343 trigger_security_request = trigger_security_request || have_ltk; 1344 #endif 1345 1346 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1347 (int) sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1348 1349 if (trigger_security_request){ 1350 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1351 if (have_ltk){ 1352 sm_reencryption_started(sm_connection); 1353 } else { 1354 sm_pairing_started(sm_connection); 1355 } 1356 sm_trigger_run(); 1357 } 1358 #endif 1359 } else { 1360 1361 #ifdef ENABLE_LE_CENTRAL 1362 // check if pairing already requested and reset requests 1363 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1364 bool auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; 1365 1366 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1367 (int) sm_connection->sm_pairing_requested, (int) sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1368 sm_connection->sm_security_request_received = false; 1369 sm_connection->sm_pairing_requested = false; 1370 bool trigger_reencryption = false; 1371 1372 if (have_ltk){ 1373 if (trigger_pairing){ 1374 // if pairing is requested, re-encryption is sufficient, if ltk is already authenticated or we don't require authentication 1375 trigger_reencryption = (authenticated != 0) || (auth_required == false); 1376 } else { 1377 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1378 trigger_reencryption = true; 1379 #else 1380 log_info("central: defer enabling encryption for bonded device"); 1381 #endif 1382 } 1383 } 1384 1385 if (trigger_reencryption){ 1386 log_info("central: enable encryption for bonded device"); 1387 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1388 break; 1389 } 1390 1391 // pairing_request -> send pairing request 1392 if (trigger_pairing){ 1393 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1394 break; 1395 } 1396 #endif 1397 } 1398 break; 1399 case ADDRESS_RESOLUTION_FAILED: 1400 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1401 if (IS_RESPONDER(sm_connection->sm_role)) { 1402 #ifdef ENABLE_LE_PERIPHERAL 1403 // LTK request received before, IRK required -> negative LTK reply 1404 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1405 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1406 } 1407 // send security request if requested 1408 bool trigger_security_request = sm_connection->sm_pairing_requested || sm_slave_request_security; 1409 sm_connection->sm_pairing_requested = false; 1410 if (trigger_security_request){ 1411 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1412 sm_pairing_started(sm_connection); 1413 } 1414 break; 1415 #endif 1416 } 1417 #ifdef ENABLE_LE_CENTRAL 1418 if ((sm_connection->sm_pairing_requested == false) && (sm_connection->sm_security_request_received == false)) break; 1419 sm_connection->sm_security_request_received = false; 1420 sm_connection->sm_pairing_requested = false; 1421 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1422 #endif 1423 break; 1424 1425 default: 1426 btstack_assert(false); 1427 break; 1428 } 1429 break; 1430 default: 1431 break; 1432 } 1433 1434 switch (event){ 1435 case ADDRESS_RESOLUTION_SUCCEEDED: 1436 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1437 break; 1438 case ADDRESS_RESOLUTION_FAILED: 1439 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1440 break; 1441 default: 1442 btstack_assert(false); 1443 break; 1444 } 1445 } 1446 1447 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1448 int le_db_index = -1; 1449 1450 // lookup device based on IRK 1451 if ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 1452 int i; 1453 for (i=0; i < le_device_db_max_count(); i++){ 1454 sm_key_t irk; 1455 bd_addr_t address; 1456 int address_type = BD_ADDR_TYPE_UNKNOWN; 1457 le_device_db_info(i, &address_type, address, irk); 1458 // skip unused entries 1459 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1460 // compare Identity Address 1461 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1462 // compare Identity Resolving Key 1463 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1464 1465 log_info("sm: device found for IRK, updating"); 1466 le_db_index = i; 1467 break; 1468 } 1469 } else { 1470 // assert IRK is set to zero 1471 memset(setup->sm_peer_irk, 0, 16); 1472 } 1473 1474 // if not found, lookup via public address if possible 1475 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1476 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1477 int i; 1478 for (i=0; i < le_device_db_max_count(); i++){ 1479 bd_addr_t address; 1480 int address_type = BD_ADDR_TYPE_UNKNOWN; 1481 le_device_db_info(i, &address_type, address, NULL); 1482 // skip unused entries 1483 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1484 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1485 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1486 log_info("sm: device found for public address, updating"); 1487 le_db_index = i; 1488 break; 1489 } 1490 } 1491 } 1492 1493 // if not found, add to db 1494 bool new_to_le_device_db = false; 1495 if (le_db_index < 0) { 1496 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1497 new_to_le_device_db = true; 1498 } 1499 1500 if (le_db_index >= 0){ 1501 1502 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1503 if (!new_to_le_device_db){ 1504 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1505 } 1506 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1507 #else 1508 UNUSED(new_to_le_device_db); 1509 #endif 1510 1511 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1512 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1513 sm_conn->sm_le_db_index = le_db_index; 1514 1515 #ifdef ENABLE_LE_SIGNED_WRITE 1516 // store local CSRK 1517 setup->sm_le_device_index = le_db_index; 1518 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1519 log_info("sm: store local CSRK"); 1520 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1521 le_device_db_local_counter_set(le_db_index, 0); 1522 } 1523 1524 // store remote CSRK 1525 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1526 log_info("sm: store remote CSRK"); 1527 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1528 le_device_db_remote_counter_set(le_db_index, 0); 1529 } 1530 #endif 1531 // store encryption information for secure connections: LTK generated by ECDH 1532 if (setup->sm_use_secure_connections){ 1533 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1534 uint8_t zero_rand[8]; 1535 memset(zero_rand, 0, 8); 1536 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1537 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1538 } 1539 1540 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1541 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1542 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1543 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1544 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1545 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1546 1547 } 1548 } 1549 } 1550 1551 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1552 sm_conn->sm_pairing_failed_reason = reason; 1553 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1554 } 1555 1556 static int sm_le_device_db_index_lookup(bd_addr_type_t address_type, bd_addr_t address){ 1557 int i; 1558 for (i=0; i < le_device_db_max_count(); i++){ 1559 bd_addr_t db_address; 1560 int db_address_type = BD_ADDR_TYPE_UNKNOWN; 1561 le_device_db_info(i, &db_address_type, db_address, NULL); 1562 // skip unused entries 1563 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1564 if ((address_type == (unsigned int)db_address_type) && (memcmp(address, db_address, 6) == 0)){ 1565 return i; 1566 } 1567 } 1568 return -1; 1569 } 1570 1571 static void sm_remove_le_device_db_entry(uint16_t i) { 1572 le_device_db_remove(i); 1573 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1574 // to remove an entry from the resolving list requires its identity address, which was already deleted 1575 // fully reload resolving list instead 1576 gap_load_resolving_list_from_le_device_db(); 1577 #endif 1578 } 1579 1580 static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){ 1581 // if identity is provided, abort if we have bonding with same address but different irk 1582 if ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 1583 int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, setup->sm_peer_address); 1584 if (index >= 0){ 1585 sm_key_t irk; 1586 le_device_db_info(index, NULL, NULL, irk); 1587 if (memcmp(irk, setup->sm_peer_irk, 16) != 0){ 1588 // IRK doesn't match, delete bonding information 1589 log_info("New IRK for %s (type %u) does not match stored IRK -> delete bonding information", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); 1590 sm_remove_le_device_db_entry(index); 1591 } 1592 } 1593 } 1594 return 0; 1595 } 1596 1597 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1598 1599 // abort pairing if received keys are not valid 1600 uint8_t reason = sm_key_distribution_validate_received(sm_conn); 1601 if (reason != 0){ 1602 sm_pairing_error(sm_conn, reason); 1603 return; 1604 } 1605 1606 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1607 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1608 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1609 & SM_AUTHREQ_BONDING ) != 0u; 1610 1611 if (bonding_enabled){ 1612 sm_store_bonding_information(sm_conn); 1613 } else { 1614 log_info("Ignoring received keys, bonding not enabled"); 1615 } 1616 } 1617 1618 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1619 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1620 } 1621 1622 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1623 1624 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1625 static bool sm_passkey_used(stk_generation_method_t method); 1626 static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1627 1628 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1629 if (setup->sm_stk_generation_method == OOB){ 1630 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1631 } else { 1632 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); 1633 } 1634 } 1635 1636 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1637 if (IS_RESPONDER(sm_conn->sm_role)){ 1638 // Responder 1639 if (setup->sm_stk_generation_method == OOB){ 1640 // generate Nb 1641 log_info("Generate Nb"); 1642 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); 1643 } else { 1644 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1645 } 1646 } else { 1647 // Initiator role 1648 switch (setup->sm_stk_generation_method){ 1649 case JUST_WORKS: 1650 sm_sc_prepare_dhkey_check(sm_conn); 1651 break; 1652 1653 case NUMERIC_COMPARISON: 1654 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1655 break; 1656 case PK_INIT_INPUT: 1657 case PK_RESP_INPUT: 1658 case PK_BOTH_INPUT: 1659 if (setup->sm_passkey_bit < 20u) { 1660 sm_sc_start_calculating_local_confirm(sm_conn); 1661 } else { 1662 sm_sc_prepare_dhkey_check(sm_conn); 1663 } 1664 break; 1665 case OOB: 1666 sm_sc_prepare_dhkey_check(sm_conn); 1667 break; 1668 default: 1669 btstack_assert(false); 1670 break; 1671 } 1672 } 1673 } 1674 1675 static void sm_sc_cmac_done(uint8_t * hash){ 1676 log_info("sm_sc_cmac_done: "); 1677 log_info_hexdump(hash, 16); 1678 1679 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1680 sm_sc_oob_state = SM_SC_OOB_IDLE; 1681 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1682 return; 1683 } 1684 1685 sm_connection_t * sm_conn = sm_cmac_connection; 1686 sm_cmac_connection = NULL; 1687 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1688 link_key_type_t link_key_type; 1689 #endif 1690 1691 switch (sm_conn->sm_engine_state){ 1692 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1693 (void)memcpy(setup->sm_local_confirm, hash, 16); 1694 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1695 break; 1696 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1697 // check 1698 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1699 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1700 break; 1701 } 1702 sm_sc_state_after_receiving_random(sm_conn); 1703 break; 1704 case SM_SC_W4_CALCULATE_G2: { 1705 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1706 big_endian_store_32(setup->sm_tk, 12, vab); 1707 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1708 sm_trigger_user_response(sm_conn); 1709 break; 1710 } 1711 case SM_SC_W4_CALCULATE_F5_SALT: 1712 (void)memcpy(setup->sm_t, hash, 16); 1713 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1714 break; 1715 case SM_SC_W4_CALCULATE_F5_MACKEY: 1716 (void)memcpy(setup->sm_mackey, hash, 16); 1717 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1718 break; 1719 case SM_SC_W4_CALCULATE_F5_LTK: 1720 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1721 // Errata Service Release to the Bluetooth Specification: ESR09 1722 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1723 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1724 (void)memcpy(setup->sm_ltk, hash, 16); 1725 (void)memcpy(setup->sm_local_ltk, hash, 16); 1726 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1727 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1728 break; 1729 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1730 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1731 if (IS_RESPONDER(sm_conn->sm_role)){ 1732 // responder 1733 if ((setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED) != 0u){ 1734 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1735 } else { 1736 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1737 } 1738 } else { 1739 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1740 } 1741 break; 1742 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1743 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1744 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1745 break; 1746 } 1747 if (IS_RESPONDER(sm_conn->sm_role)){ 1748 // responder 1749 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1750 } else { 1751 // initiator 1752 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1753 } 1754 break; 1755 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1756 case SM_SC_W4_CALCULATE_ILK: 1757 (void)memcpy(setup->sm_t, hash, 16); 1758 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1759 break; 1760 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1761 reverse_128(hash, setup->sm_t); 1762 link_key_type = sm_conn->sm_connection_authenticated ? 1763 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1764 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1765 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1766 if (IS_RESPONDER(sm_conn->sm_role)){ 1767 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1768 } else { 1769 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1770 } 1771 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1772 sm_done_for_handle(sm_conn->sm_handle); 1773 break; 1774 case SM_BR_EDR_W4_CALCULATE_ILK: 1775 (void)memcpy(setup->sm_t, hash, 16); 1776 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1777 break; 1778 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1779 log_info("Derived LE LTK from BR/EDR Link Key"); 1780 log_info_key("Link Key", hash); 1781 (void)memcpy(setup->sm_ltk, hash, 16); 1782 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1783 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1784 sm_store_bonding_information(sm_conn); 1785 sm_done_for_handle(sm_conn->sm_handle); 1786 break; 1787 #endif 1788 default: 1789 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1790 break; 1791 } 1792 sm_trigger_run(); 1793 } 1794 1795 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){ 1796 const uint16_t message_len = 65; 1797 sm_cmac_connection = sm_conn; 1798 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1799 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1800 sm_cmac_sc_buffer[64] = z; 1801 log_info("f4 key"); 1802 log_info_hexdump(x, 16); 1803 log_info("f4 message"); 1804 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1805 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1806 } 1807 1808 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1809 static const uint8_t f5_length[] = { 0x01, 0x00}; 1810 1811 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1812 1813 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1814 1815 log_info("f5_calculate_salt"); 1816 // calculate salt for f5 1817 const uint16_t message_len = 32; 1818 sm_cmac_connection = sm_conn; 1819 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1820 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1821 } 1822 1823 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){ 1824 const uint16_t message_len = 53; 1825 sm_cmac_connection = sm_conn; 1826 1827 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1828 sm_cmac_sc_buffer[0] = 0; 1829 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1830 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1831 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1832 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1833 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1834 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1835 log_info("f5 key"); 1836 log_info_hexdump(t, 16); 1837 log_info("f5 message for MacKey"); 1838 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1839 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1840 } 1841 1842 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1843 sm_key56_t bd_addr_master, bd_addr_slave; 1844 bd_addr_master[0] = setup->sm_m_addr_type; 1845 bd_addr_slave[0] = setup->sm_s_addr_type; 1846 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1847 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1848 if (IS_RESPONDER(sm_conn->sm_role)){ 1849 // responder 1850 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1851 } else { 1852 // initiator 1853 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1854 } 1855 } 1856 1857 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1858 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1859 const uint16_t message_len = 53; 1860 sm_cmac_connection = sm_conn; 1861 sm_cmac_sc_buffer[0] = 1; 1862 // 1..52 setup before 1863 log_info("f5 key"); 1864 log_info_hexdump(t, 16); 1865 log_info("f5 message for LTK"); 1866 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1867 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1868 } 1869 1870 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1871 f5_ltk(sm_conn, setup->sm_t); 1872 } 1873 1874 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){ 1875 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1876 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1877 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1878 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1879 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1880 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1881 } 1882 1883 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1884 const uint16_t message_len = 65; 1885 sm_cmac_connection = sm_conn; 1886 log_info("f6 key"); 1887 log_info_hexdump(w, 16); 1888 log_info("f6 message"); 1889 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1890 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1891 } 1892 1893 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1894 // - U is 256 bits 1895 // - V is 256 bits 1896 // - X is 128 bits 1897 // - Y is 128 bits 1898 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){ 1899 const uint16_t message_len = 80; 1900 sm_cmac_connection = sm_conn; 1901 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1902 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1903 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1904 log_info("g2 key"); 1905 log_info_hexdump(x, 16); 1906 log_info("g2 message"); 1907 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1908 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1909 } 1910 1911 static void g2_calculate(sm_connection_t * sm_conn) { 1912 // calc Va if numeric comparison 1913 if (IS_RESPONDER(sm_conn->sm_role)){ 1914 // responder 1915 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1916 } else { 1917 // initiator 1918 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1919 } 1920 } 1921 1922 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1923 uint8_t z = 0; 1924 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1925 // some form of passkey 1926 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1927 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1928 setup->sm_passkey_bit++; 1929 } 1930 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1931 } 1932 1933 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1934 // OOB 1935 if (setup->sm_stk_generation_method == OOB){ 1936 if (IS_RESPONDER(sm_conn->sm_role)){ 1937 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1938 } else { 1939 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1940 } 1941 return; 1942 } 1943 1944 uint8_t z = 0; 1945 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1946 // some form of passkey 1947 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1948 // sm_passkey_bit was increased before sending confirm value 1949 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1950 } 1951 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1952 } 1953 1954 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1955 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) != 0 ? 1 : 0); 1956 1957 if ((setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) != 0u){ 1958 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1959 } else { 1960 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1961 } 1962 } 1963 1964 static void sm_sc_dhkey_calculated(void * arg){ 1965 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1966 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1967 if (sm_conn == NULL) return; 1968 1969 // check for invalid public key detected by Controller 1970 if (sm_is_ff(setup->sm_dhkey, 32)){ 1971 log_info("sm: peer public key invalid"); 1972 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1973 return; 1974 } 1975 1976 log_info("dhkey"); 1977 log_info_hexdump(&setup->sm_dhkey[0], 32); 1978 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1979 // trigger next step 1980 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1981 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1982 } 1983 sm_trigger_run(); 1984 } 1985 1986 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1987 // calculate DHKCheck 1988 sm_key56_t bd_addr_master, bd_addr_slave; 1989 bd_addr_master[0] = setup->sm_m_addr_type; 1990 bd_addr_slave[0] = setup->sm_s_addr_type; 1991 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1992 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1993 uint8_t iocap_a[3]; 1994 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1995 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1996 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1997 uint8_t iocap_b[3]; 1998 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1999 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2000 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2001 if (IS_RESPONDER(sm_conn->sm_role)){ 2002 // responder 2003 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2004 f6_engine(sm_conn, setup->sm_mackey); 2005 } else { 2006 // initiator 2007 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2008 f6_engine(sm_conn, setup->sm_mackey); 2009 } 2010 } 2011 2012 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 2013 // validate E = f6() 2014 sm_key56_t bd_addr_master, bd_addr_slave; 2015 bd_addr_master[0] = setup->sm_m_addr_type; 2016 bd_addr_slave[0] = setup->sm_s_addr_type; 2017 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2018 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2019 2020 uint8_t iocap_a[3]; 2021 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2022 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2023 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2024 uint8_t iocap_b[3]; 2025 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2026 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2027 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2028 if (IS_RESPONDER(sm_conn->sm_role)){ 2029 // responder 2030 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2031 f6_engine(sm_conn, setup->sm_mackey); 2032 } else { 2033 // initiator 2034 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2035 f6_engine(sm_conn, setup->sm_mackey); 2036 } 2037 } 2038 2039 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2040 2041 // 2042 // Link Key Conversion Function h6 2043 // 2044 // h6(W, keyID) = AES-CMAC_W(keyID) 2045 // - W is 128 bits 2046 // - keyID is 32 bits 2047 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 2048 const uint16_t message_len = 4; 2049 sm_cmac_connection = sm_conn; 2050 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 2051 log_info("h6 key"); 2052 log_info_hexdump(w, 16); 2053 log_info("h6 message"); 2054 log_info_hexdump(sm_cmac_sc_buffer, message_len); 2055 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 2056 } 2057 // 2058 // Link Key Conversion Function h7 2059 // 2060 // h7(SALT, W) = AES-CMAC_SALT(W) 2061 // - SALT is 128 bits 2062 // - W is 128 bits 2063 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 2064 const uint16_t message_len = 16; 2065 sm_cmac_connection = sm_conn; 2066 log_info("h7 key"); 2067 log_info_hexdump(salt, 16); 2068 log_info("h7 message"); 2069 log_info_hexdump(w, 16); 2070 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 2071 } 2072 2073 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2074 // Errata Service Release to the Bluetooth Specification: ESR09 2075 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2076 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2077 2078 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2079 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2080 } 2081 2082 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2083 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2084 } 2085 2086 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2087 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2088 } 2089 2090 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2091 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2092 } 2093 2094 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2095 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2096 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2097 } 2098 2099 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2100 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2101 h7_engine(sm_conn, salt, setup->sm_link_key); 2102 } 2103 2104 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2105 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2106 btstack_assert(hci_connection != NULL); 2107 reverse_128(hci_connection->link_key, setup->sm_link_key); 2108 setup->sm_link_key_type = hci_connection->link_key_type; 2109 } 2110 2111 static void sm_ctkd_start_from_br_edr(sm_connection_t * sm_conn){ 2112 // only derive LTK if EncKey is set by both 2113 bool derive_ltk = (sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & 2114 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & SM_KEYDIST_ENC_KEY) != 0; 2115 if (derive_ltk){ 2116 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; 2117 sm_conn->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2118 } else { 2119 sm_done_for_handle(sm_conn->sm_handle); 2120 } 2121 } 2122 2123 #endif 2124 2125 #endif 2126 2127 // key management legacy connections: 2128 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2129 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2130 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2131 // - responder reconnects: responder uses LTK receveived from master 2132 2133 // key management secure connections: 2134 // - both devices store same LTK from ECDH key exchange. 2135 2136 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2137 static void sm_load_security_info(sm_connection_t * sm_connection){ 2138 int encryption_key_size; 2139 int authenticated; 2140 int authorized; 2141 int secure_connection; 2142 2143 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2144 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2145 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2146 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); 2147 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2148 sm_connection->sm_connection_authenticated = authenticated; 2149 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2150 sm_connection->sm_connection_sc = secure_connection != 0; 2151 } 2152 #endif 2153 2154 #ifdef ENABLE_LE_PERIPHERAL 2155 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2156 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2157 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2158 // re-establish used key encryption size 2159 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2160 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2161 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2162 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2163 // Legacy paring -> not SC 2164 sm_connection->sm_connection_sc = false; 2165 log_info("sm: received ltk request with key size %u, authenticated %u", 2166 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2167 } 2168 #endif 2169 2170 // distributed key generation 2171 static bool sm_run_dpkg(void){ 2172 switch (dkg_state){ 2173 case DKG_CALC_IRK: 2174 // already busy? 2175 if (sm_aes128_state == SM_AES128_IDLE) { 2176 log_info("DKG_CALC_IRK started"); 2177 // IRK = d1(IR, 1, 0) 2178 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2179 sm_aes128_state = SM_AES128_ACTIVE; 2180 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2181 return true; 2182 } 2183 break; 2184 case DKG_CALC_DHK: 2185 // already busy? 2186 if (sm_aes128_state == SM_AES128_IDLE) { 2187 log_info("DKG_CALC_DHK started"); 2188 // DHK = d1(IR, 3, 0) 2189 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2190 sm_aes128_state = SM_AES128_ACTIVE; 2191 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2192 return true; 2193 } 2194 break; 2195 default: 2196 break; 2197 } 2198 return false; 2199 } 2200 2201 // random address updates 2202 static bool sm_run_rau(void){ 2203 switch (rau_state){ 2204 case RAU_GET_RANDOM: 2205 rau_state = RAU_W4_RANDOM; 2206 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2207 return true; 2208 case RAU_GET_ENC: 2209 // already busy? 2210 if (sm_aes128_state == SM_AES128_IDLE) { 2211 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2212 sm_aes128_state = SM_AES128_ACTIVE; 2213 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2214 return true; 2215 } 2216 break; 2217 default: 2218 break; 2219 } 2220 return false; 2221 } 2222 2223 // CSRK Lookup 2224 static bool sm_run_csrk(void){ 2225 btstack_linked_list_iterator_t it; 2226 2227 // -- if csrk lookup ready, find connection that require csrk lookup 2228 if (sm_address_resolution_idle()){ 2229 hci_connections_get_iterator(&it); 2230 while(btstack_linked_list_iterator_has_next(&it)){ 2231 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2232 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2233 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2234 // and start lookup 2235 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); 2236 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2237 break; 2238 } 2239 } 2240 } 2241 2242 // -- if csrk lookup ready, resolved addresses for received addresses 2243 if (sm_address_resolution_idle()) { 2244 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2245 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2246 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2247 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2248 btstack_memory_sm_lookup_entry_free(entry); 2249 } 2250 } 2251 2252 // -- Continue with device lookup by public or resolvable private address 2253 if (!sm_address_resolution_idle()){ 2254 while (sm_address_resolution_test < le_device_db_max_count()){ 2255 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2256 bd_addr_t addr; 2257 sm_key_t irk; 2258 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2259 2260 // skip unused entries 2261 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2262 sm_address_resolution_test++; 2263 continue; 2264 } 2265 2266 log_info("LE Device Lookup: device %u of %u", sm_address_resolution_test, le_device_db_max_count()); 2267 2268 // map resolved identiry addresses to regular addresses 2269 int regular_addr_type = sm_address_resolution_addr_type & 1; 2270 if ((regular_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2271 log_info("LE Device Lookup: found by { addr_type, address} "); 2272 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2273 break; 2274 } 2275 2276 // if connection type is public, it must be a different one 2277 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2278 sm_address_resolution_test++; 2279 continue; 2280 } 2281 2282 // skip AH if no IRK 2283 if (sm_is_null_key(irk)){ 2284 sm_address_resolution_test++; 2285 continue; 2286 } 2287 2288 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2289 2290 log_info("LE Device Lookup: calculate AH"); 2291 log_info_key("IRK", irk); 2292 2293 (void)memcpy(sm_aes128_key, irk, 16); 2294 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2295 sm_aes128_state = SM_AES128_ACTIVE; 2296 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2297 return true; 2298 } 2299 2300 if (sm_address_resolution_test >= le_device_db_max_count()){ 2301 log_info("LE Device Lookup: not found"); 2302 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2303 } 2304 } 2305 return false; 2306 } 2307 2308 // SC OOB 2309 static bool sm_run_oob(void){ 2310 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2311 switch (sm_sc_oob_state){ 2312 case SM_SC_OOB_W2_CALC_CONFIRM: 2313 if (!sm_cmac_ready()) break; 2314 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2315 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2316 return true; 2317 default: 2318 break; 2319 } 2320 #endif 2321 return false; 2322 } 2323 2324 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2325 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2326 } 2327 2328 // handle basic actions that don't requires the full context 2329 static bool sm_run_basic(void){ 2330 btstack_linked_list_iterator_t it; 2331 hci_connections_get_iterator(&it); 2332 while(btstack_linked_list_iterator_has_next(&it)){ 2333 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2334 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2335 switch(sm_connection->sm_engine_state){ 2336 2337 // general 2338 case SM_GENERAL_SEND_PAIRING_FAILED: { 2339 uint8_t buffer[2]; 2340 buffer[0] = SM_CODE_PAIRING_FAILED; 2341 buffer[1] = sm_connection->sm_pairing_failed_reason; 2342 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2343 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2344 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2345 sm_done_for_handle(sm_connection->sm_handle); 2346 break; 2347 } 2348 2349 // responder side 2350 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2351 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2352 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2353 return true; 2354 2355 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2356 case SM_SC_RECEIVED_LTK_REQUEST: 2357 switch (sm_connection->sm_irk_lookup_state){ 2358 case IRK_LOOKUP_FAILED: 2359 log_info("LTK Request: IRK Lookup Failed)"); 2360 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2361 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2362 return true; 2363 default: 2364 break; 2365 } 2366 break; 2367 #endif 2368 default: 2369 break; 2370 } 2371 } 2372 return false; 2373 } 2374 2375 static void sm_run_activate_connection(void){ 2376 // Find connections that requires setup context and make active if no other is locked 2377 btstack_linked_list_iterator_t it; 2378 hci_connections_get_iterator(&it); 2379 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2380 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2381 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2382 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2383 bool done = true; 2384 int err; 2385 UNUSED(err); 2386 2387 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2388 // assert ec key is ready 2389 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2390 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2391 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2392 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2393 sm_ec_generate_new_key(); 2394 } 2395 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2396 continue; 2397 } 2398 } 2399 #endif 2400 2401 switch (sm_connection->sm_engine_state) { 2402 #ifdef ENABLE_LE_PERIPHERAL 2403 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2404 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2405 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2406 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2407 case SM_SC_RECEIVED_LTK_REQUEST: 2408 #endif 2409 #endif 2410 #ifdef ENABLE_LE_CENTRAL 2411 case SM_INITIATOR_PH4_HAS_LTK: 2412 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2413 #endif 2414 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2415 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2416 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2417 #endif 2418 // just lock context 2419 break; 2420 default: 2421 done = false; 2422 break; 2423 } 2424 if (done){ 2425 sm_active_connection_handle = sm_connection->sm_handle; 2426 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); 2427 } 2428 } 2429 } 2430 2431 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2432 int i; 2433 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2434 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2435 uint8_t action = 0; 2436 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2437 if ((flags & (1u<<i)) != 0u){ 2438 bool clear_flag = true; 2439 switch (i){ 2440 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2441 case SM_KEYPRESS_PASSKEY_CLEARED: 2442 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2443 default: 2444 break; 2445 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2446 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2447 num_actions--; 2448 clear_flag = num_actions == 0u; 2449 break; 2450 } 2451 if (clear_flag){ 2452 flags &= ~(1<<i); 2453 } 2454 action = i; 2455 break; 2456 } 2457 } 2458 setup->sm_keypress_notification = (num_actions << 5) | flags; 2459 2460 // send keypress notification 2461 uint8_t buffer[2]; 2462 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2463 buffer[1] = action; 2464 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2465 2466 // try 2467 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2468 } 2469 2470 static void sm_run_distribute_keys(sm_connection_t * connection){ 2471 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) != 0u){ 2472 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2473 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2474 uint8_t buffer[17]; 2475 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2476 reverse_128(setup->sm_ltk, &buffer[1]); 2477 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2478 sm_timeout_reset(connection); 2479 return; 2480 } 2481 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION) != 0u){ 2482 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2483 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2484 uint8_t buffer[11]; 2485 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2486 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2487 reverse_64(setup->sm_local_rand, &buffer[3]); 2488 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2489 sm_timeout_reset(connection); 2490 return; 2491 } 2492 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 2493 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2494 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2495 uint8_t buffer[17]; 2496 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2497 reverse_128(sm_persistent_irk, &buffer[1]); 2498 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2499 sm_timeout_reset(connection); 2500 return; 2501 } 2502 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0u){ 2503 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2504 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2505 bd_addr_t local_address; 2506 uint8_t buffer[8]; 2507 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2508 switch (gap_random_address_get_mode()){ 2509 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2510 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2511 // public or static random 2512 gap_le_get_own_address(&buffer[1], local_address); 2513 break; 2514 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2515 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2516 // fallback to public 2517 gap_local_bd_addr(local_address); 2518 buffer[1] = 0; 2519 break; 2520 default: 2521 btstack_assert(false); 2522 break; 2523 } 2524 reverse_bd_addr(local_address, &buffer[2]); 2525 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2526 sm_timeout_reset(connection); 2527 return; 2528 } 2529 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION) != 0u){ 2530 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2531 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2532 2533 #ifdef ENABLE_LE_SIGNED_WRITE 2534 // hack to reproduce test runs 2535 if (test_use_fixed_local_csrk){ 2536 memset(setup->sm_local_csrk, 0xcc, 16); 2537 } 2538 2539 // store local CSRK 2540 if (setup->sm_le_device_index >= 0){ 2541 log_info("sm: store local CSRK"); 2542 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2543 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2544 } 2545 #endif 2546 2547 uint8_t buffer[17]; 2548 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2549 reverse_128(setup->sm_local_csrk, &buffer[1]); 2550 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2551 sm_timeout_reset(connection); 2552 return; 2553 } 2554 btstack_assert(false); 2555 } 2556 2557 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2558 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2559 // requirements to derive link key from LE: 2560 // - use secure connections 2561 if (setup->sm_use_secure_connections == 0) return false; 2562 // - bonding needs to be enabled: 2563 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; 2564 if (!bonding_enabled) return false; 2565 // - need identity address / public addr 2566 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2567 if (!have_identity_address_info) return false; 2568 // - 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) 2569 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2570 // If SC is authenticated, we consider it safe to overwrite a stored key. 2571 // 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. 2572 uint8_t link_key[16]; 2573 link_key_type_t link_key_type; 2574 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2575 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2576 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2577 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2578 return false; 2579 } 2580 // get started (all of the above are true) 2581 return true; 2582 #else 2583 UNUSED(sm_connection); 2584 return false; 2585 #endif 2586 } 2587 2588 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2589 static bool sm_ctkd_from_classic(sm_connection_t * sm_connection){ 2590 hci_connection_t * hci_connection = hci_connection_for_handle(sm_connection->sm_handle); 2591 btstack_assert(hci_connection != NULL); 2592 // requirements to derive ltk from BR/EDR: 2593 // - BR/EDR uses secure connections 2594 if (gap_secure_connection_for_link_key_type(hci_connection->link_key_type) == false) return false; 2595 // - bonding needs to be enabled: 2596 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; 2597 if (!bonding_enabled) return false; 2598 // - there is no stored LTK or the derived key has at least the same level of authentication (bail if LTK is authenticated but Link Key isn't) 2599 bool link_key_authenticated = gap_authenticated_for_link_key_type(hci_connection->link_key_type); 2600 if (link_key_authenticated) return true; 2601 int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, hci_connection->address); 2602 if (index >= 0){ 2603 int ltk_authenticated; 2604 sm_key_t ltk; 2605 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, <k_authenticated, NULL, NULL); 2606 bool have_ltk = !sm_is_null_key(ltk); 2607 if (have_ltk && ltk_authenticated) return false; 2608 } 2609 return true; 2610 } 2611 #endif 2612 2613 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2614 if (sm_ctkd_from_le(connection)){ 2615 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; 2616 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2617 } else { 2618 connection->sm_engine_state = SM_RESPONDER_IDLE; 2619 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2620 sm_done_for_handle(connection->sm_handle); 2621 } 2622 } 2623 2624 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2625 if (sm_ctkd_from_le(connection)){ 2626 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; 2627 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2628 } else { 2629 sm_master_pairing_success(connection); 2630 } 2631 } 2632 2633 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2634 static void sm_run_state_sc_send_confirmation(sm_connection_t *connection) { 2635 uint8_t buffer[17]; 2636 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2637 reverse_128(setup->sm_local_confirm, &buffer[1]); 2638 if (IS_RESPONDER(connection->sm_role)){ 2639 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2640 } else { 2641 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2642 } 2643 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2644 sm_timeout_reset(connection); 2645 } 2646 2647 static void sm_run_state_sc_send_pairing_random(sm_connection_t *connection) { 2648 uint8_t buffer[17]; 2649 buffer[0] = SM_CODE_PAIRING_RANDOM; 2650 reverse_128(setup->sm_local_nonce, &buffer[1]); 2651 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2652 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2653 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2654 if (IS_RESPONDER(connection->sm_role)){ 2655 // responder 2656 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2657 } else { 2658 // initiator 2659 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2660 } 2661 } else { 2662 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2663 if (IS_RESPONDER(connection->sm_role)){ 2664 // responder 2665 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2666 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2667 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2668 } else { 2669 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2670 sm_sc_prepare_dhkey_check(connection); 2671 } 2672 } else { 2673 // initiator 2674 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2675 } 2676 } 2677 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2678 sm_timeout_reset(connection); 2679 } 2680 2681 static void sm_run_state_sc_send_dhkey_check_command(sm_connection_t *connection) { 2682 uint8_t buffer[17]; 2683 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2684 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2685 2686 if (IS_RESPONDER(connection->sm_role)){ 2687 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2688 } else { 2689 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2690 } 2691 2692 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2693 sm_timeout_reset(connection); 2694 } 2695 2696 static void sm_run_state_sc_send_public_key_command(sm_connection_t *connection) { 2697 bool trigger_user_response = false; 2698 bool trigger_start_calculating_local_confirm = false; 2699 uint8_t buffer[65]; 2700 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2701 // 2702 reverse_256(&ec_q[0], &buffer[1]); 2703 reverse_256(&ec_q[32], &buffer[33]); 2704 2705 #ifdef ENABLE_TESTING_SUPPORT 2706 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2707 log_info("testing_support: invalidating public key"); 2708 // flip single bit of public key coordinate 2709 buffer[1] ^= 1; 2710 } 2711 #endif 2712 2713 // stk generation method 2714 // passkey entry: notify app to show passkey or to request passkey 2715 switch (setup->sm_stk_generation_method){ 2716 case JUST_WORKS: 2717 case NUMERIC_COMPARISON: 2718 if (IS_RESPONDER(connection->sm_role)){ 2719 // responder 2720 trigger_start_calculating_local_confirm = true; 2721 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2722 } else { 2723 // initiator 2724 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2725 } 2726 break; 2727 case PK_INIT_INPUT: 2728 case PK_RESP_INPUT: 2729 case PK_BOTH_INPUT: 2730 // use random TK for display 2731 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2732 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2733 setup->sm_passkey_bit = 0; 2734 2735 if (IS_RESPONDER(connection->sm_role)){ 2736 // responder 2737 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2738 } else { 2739 // initiator 2740 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2741 } 2742 trigger_user_response = true; 2743 break; 2744 case OOB: 2745 if (IS_RESPONDER(connection->sm_role)){ 2746 // responder 2747 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2748 } else { 2749 // initiator 2750 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2751 } 2752 break; 2753 default: 2754 btstack_assert(false); 2755 break; 2756 } 2757 2758 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2759 sm_timeout_reset(connection); 2760 2761 // trigger user response and calc confirm after sending pdu 2762 if (trigger_user_response){ 2763 sm_trigger_user_response(connection); 2764 } 2765 if (trigger_start_calculating_local_confirm){ 2766 sm_sc_start_calculating_local_confirm(connection); 2767 } 2768 } 2769 #endif 2770 2771 static bool sm_run_non_connection_logic(void){ 2772 bool done;; 2773 2774 done = sm_run_dpkg(); 2775 if (done) return true; 2776 2777 done = sm_run_rau(); 2778 if (done) return true; 2779 2780 done = sm_run_csrk(); 2781 if (done) return true; 2782 2783 done = sm_run_oob(); 2784 return done; 2785 } 2786 2787 static void sm_run(void){ 2788 2789 // assert that stack has already bootet 2790 if (hci_get_state() != HCI_STATE_WORKING) return; 2791 2792 // assert that we can send at least commands 2793 if (!hci_can_send_command_packet_now()) return; 2794 2795 // pause until IR/ER are ready 2796 if (sm_persistent_keys_random_active) return; 2797 2798 // non-connection related behaviour 2799 bool done = sm_run_non_connection_logic(); 2800 if (done) return; 2801 2802 // assert that we can send at least commands - cmd might have been sent by crypto engine 2803 if (!hci_can_send_command_packet_now()) return; 2804 2805 // handle basic actions that don't requires the full context 2806 done = sm_run_basic(); 2807 if (done) return; 2808 2809 // 2810 // active connection handling 2811 // -- use loop to handle next connection if lock on setup context is released 2812 2813 while (true) { 2814 2815 sm_run_activate_connection(); 2816 2817 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2818 2819 // 2820 // active connection handling 2821 // 2822 2823 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2824 if (!connection) { 2825 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2826 return; 2827 } 2828 2829 // assert that we could send a SM PDU - not needed for all of the following 2830 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2831 log_info("cannot send now, requesting can send now event"); 2832 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2833 return; 2834 } 2835 2836 // send keypress notifications 2837 if (setup->sm_keypress_notification != 0u){ 2838 sm_run_send_keypress_notification(connection); 2839 return; 2840 } 2841 2842 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2843 // assert that sm cmac engine is ready 2844 if (sm_cmac_ready() == false){ 2845 break; 2846 } 2847 #endif 2848 2849 int key_distribution_flags; 2850 UNUSED(key_distribution_flags); 2851 #ifdef ENABLE_LE_PERIPHERAL 2852 int err; 2853 bool have_ltk; 2854 uint8_t ltk[16]; 2855 #endif 2856 2857 log_info("sm_run: state %u", connection->sm_engine_state); 2858 switch (connection->sm_engine_state){ 2859 2860 // secure connections, initiator + responding states 2861 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2862 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2863 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2864 sm_sc_calculate_local_confirm(connection); 2865 break; 2866 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2867 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2868 sm_sc_calculate_remote_confirm(connection); 2869 break; 2870 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2871 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2872 sm_sc_calculate_f6_for_dhkey_check(connection); 2873 break; 2874 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2875 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2876 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2877 break; 2878 case SM_SC_W2_CALCULATE_F5_SALT: 2879 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2880 f5_calculate_salt(connection); 2881 break; 2882 case SM_SC_W2_CALCULATE_F5_MACKEY: 2883 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2884 f5_calculate_mackey(connection); 2885 break; 2886 case SM_SC_W2_CALCULATE_F5_LTK: 2887 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2888 f5_calculate_ltk(connection); 2889 break; 2890 case SM_SC_W2_CALCULATE_G2: 2891 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2892 g2_calculate(connection); 2893 break; 2894 #endif 2895 2896 #ifdef ENABLE_LE_CENTRAL 2897 // initiator side 2898 2899 case SM_INITIATOR_PH4_HAS_LTK: { 2900 sm_reset_setup(); 2901 sm_load_security_info(connection); 2902 2903 sm_key_t peer_ltk_flipped; 2904 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2905 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2906 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2907 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2908 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2909 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2910 2911 // notify after sending 2912 sm_reencryption_started(connection); 2913 return; 2914 } 2915 2916 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2917 sm_reset_setup(); 2918 sm_init_setup(connection); 2919 2920 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2921 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2922 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2923 sm_timeout_reset(connection); 2924 2925 // notify after sending 2926 sm_pairing_started(connection); 2927 break; 2928 #endif 2929 2930 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2931 case SM_SC_SEND_PUBLIC_KEY_COMMAND: 2932 sm_run_state_sc_send_public_key_command(connection); 2933 break; 2934 case SM_SC_SEND_CONFIRMATION: 2935 sm_run_state_sc_send_confirmation(connection); 2936 break; 2937 case SM_SC_SEND_PAIRING_RANDOM: 2938 sm_run_state_sc_send_pairing_random(connection); 2939 break; 2940 case SM_SC_SEND_DHKEY_CHECK_COMMAND: 2941 sm_run_state_sc_send_dhkey_check_command(connection); 2942 break; 2943 #endif 2944 2945 #ifdef ENABLE_LE_PERIPHERAL 2946 2947 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2948 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2949 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2950 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2951 sm_timeout_start(connection); 2952 break; 2953 } 2954 2955 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2956 case SM_SC_RECEIVED_LTK_REQUEST: 2957 switch (connection->sm_irk_lookup_state){ 2958 case IRK_LOOKUP_SUCCEEDED: 2959 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2960 // start using context by loading security info 2961 sm_reset_setup(); 2962 sm_load_security_info(connection); 2963 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2964 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2965 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2966 sm_reencryption_started(connection); 2967 sm_trigger_run(); 2968 break; 2969 } 2970 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2971 connection->sm_engine_state = SM_RESPONDER_IDLE; 2972 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2973 return; 2974 default: 2975 // just wait until IRK lookup is completed 2976 break; 2977 } 2978 break; 2979 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2980 2981 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2982 sm_reset_setup(); 2983 2984 // handle Pairing Request with LTK available 2985 switch (connection->sm_irk_lookup_state) { 2986 case IRK_LOOKUP_SUCCEEDED: 2987 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2988 have_ltk = !sm_is_null_key(ltk); 2989 if (have_ltk){ 2990 log_info("pairing request but LTK available"); 2991 // emit re-encryption start/fail sequence 2992 sm_reencryption_started(connection); 2993 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2994 } 2995 break; 2996 default: 2997 break; 2998 } 2999 3000 sm_init_setup(connection); 3001 3002 // recover pairing request 3003 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3004 err = sm_stk_generation_init(connection); 3005 3006 #ifdef ENABLE_TESTING_SUPPORT 3007 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 3008 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 3009 err = test_pairing_failure; 3010 } 3011 #endif 3012 if (err != 0){ 3013 // emit pairing started/failed sequence 3014 sm_pairing_started(connection); 3015 sm_pairing_error(connection, err); 3016 sm_trigger_run(); 3017 break; 3018 } 3019 3020 sm_timeout_start(connection); 3021 3022 // generate random number first, if we need to show passkey, otherwise send response 3023 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3024 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 3025 break; 3026 } 3027 3028 /* fall through */ 3029 3030 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 3031 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 3032 3033 // start with initiator key dist flags 3034 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 3035 3036 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3037 // LTK (= encryption information & master identification) only exchanged for LE Legacy Connection 3038 if (setup->sm_use_secure_connections){ 3039 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3040 } 3041 #endif 3042 // setup in response 3043 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); 3044 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); 3045 3046 // update key distribution after ENC was dropped 3047 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)); 3048 3049 if (setup->sm_use_secure_connections){ 3050 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 3051 } else { 3052 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 3053 } 3054 3055 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3056 sm_timeout_reset(connection); 3057 3058 // notify after sending 3059 sm_pairing_started(connection); 3060 3061 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3062 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 3063 sm_trigger_user_response(connection); 3064 } 3065 return; 3066 #endif 3067 3068 case SM_PH2_SEND_PAIRING_RANDOM: { 3069 uint8_t buffer[17]; 3070 buffer[0] = SM_CODE_PAIRING_RANDOM; 3071 reverse_128(setup->sm_local_random, &buffer[1]); 3072 if (IS_RESPONDER(connection->sm_role)){ 3073 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 3074 } else { 3075 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 3076 } 3077 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3078 sm_timeout_reset(connection); 3079 break; 3080 } 3081 3082 case SM_PH2_C1_GET_ENC_A: 3083 // already busy? 3084 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3085 // calculate confirm using aes128 engine - step 1 3086 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); 3087 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 3088 sm_aes128_state = SM_AES128_ACTIVE; 3089 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); 3090 break; 3091 3092 case SM_PH2_C1_GET_ENC_C: 3093 // already busy? 3094 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3095 // calculate m_confirm using aes128 engine - step 1 3096 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); 3097 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 3098 sm_aes128_state = SM_AES128_ACTIVE; 3099 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); 3100 break; 3101 3102 case SM_PH2_CALC_STK: 3103 // already busy? 3104 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3105 // calculate STK 3106 if (IS_RESPONDER(connection->sm_role)){ 3107 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 3108 } else { 3109 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3110 } 3111 connection->sm_engine_state = SM_PH2_W4_STK; 3112 sm_aes128_state = SM_AES128_ACTIVE; 3113 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); 3114 break; 3115 3116 case SM_PH3_Y_GET_ENC: 3117 // already busy? 3118 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3119 // PH3B2 - calculate Y from - enc 3120 3121 // dm helper (was sm_dm_r_prime) 3122 // r' = padding || r 3123 // r - 64 bit value 3124 memset(&sm_aes128_plaintext[0], 0, 8); 3125 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3126 3127 // Y = dm(DHK, Rand) 3128 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3129 sm_aes128_state = SM_AES128_ACTIVE; 3130 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); 3131 break; 3132 3133 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3134 uint8_t buffer[17]; 3135 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3136 reverse_128(setup->sm_local_confirm, &buffer[1]); 3137 if (IS_RESPONDER(connection->sm_role)){ 3138 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3139 } else { 3140 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3141 } 3142 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3143 sm_timeout_reset(connection); 3144 return; 3145 } 3146 #ifdef ENABLE_LE_PERIPHERAL 3147 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3148 // cache key before using 3149 sm_cache_ltk(connection, setup->sm_ltk); 3150 sm_key_t stk_flipped; 3151 reverse_128(setup->sm_ltk, stk_flipped); 3152 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3153 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3154 return; 3155 } 3156 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3157 // allow to override LTK 3158 if (sm_get_ltk_callback != NULL){ 3159 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3160 } 3161 // cache key before using 3162 sm_cache_ltk(connection, setup->sm_ltk); 3163 sm_key_t ltk_flipped; 3164 reverse_128(setup->sm_ltk, ltk_flipped); 3165 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3166 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3167 return; 3168 } 3169 3170 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3171 // already busy? 3172 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3173 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3174 3175 sm_reset_setup(); 3176 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3177 3178 sm_reencryption_started(connection); 3179 3180 // dm helper (was sm_dm_r_prime) 3181 // r' = padding || r 3182 // r - 64 bit value 3183 memset(&sm_aes128_plaintext[0], 0, 8); 3184 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3185 3186 // Y = dm(DHK, Rand) 3187 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3188 sm_aes128_state = SM_AES128_ACTIVE; 3189 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); 3190 return; 3191 #endif 3192 #ifdef ENABLE_LE_CENTRAL 3193 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3194 sm_key_t stk_flipped; 3195 reverse_128(setup->sm_ltk, stk_flipped); 3196 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3197 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3198 return; 3199 } 3200 #endif 3201 3202 case SM_PH3_DISTRIBUTE_KEYS: 3203 // send next key 3204 if (setup->sm_key_distribution_send_set != 0){ 3205 sm_run_distribute_keys(connection); 3206 } 3207 3208 // more to send? 3209 if (setup->sm_key_distribution_send_set != 0){ 3210 return; 3211 } 3212 3213 // keys are sent 3214 if (IS_RESPONDER(connection->sm_role)){ 3215 // slave -> receive master keys if any 3216 if (sm_key_distribution_all_received()){ 3217 sm_key_distribution_handle_all_received(connection); 3218 sm_key_distribution_complete_responder(connection); 3219 // start CTKD right away 3220 continue; 3221 } else { 3222 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3223 } 3224 } else { 3225 sm_master_pairing_success(connection); 3226 } 3227 break; 3228 3229 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3230 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3231 // fill in sm setup (lite version of sm_init_setup) 3232 sm_reset_setup(); 3233 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3234 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3235 setup->sm_s_addr_type = connection->sm_own_addr_type; 3236 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3237 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3238 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3239 setup->sm_use_secure_connections = true; 3240 sm_ctkd_fetch_br_edr_link_key(connection); 3241 3242 // Enc Key and IRK if requested 3243 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3244 #ifdef ENABLE_LE_SIGNED_WRITE 3245 // Plus signing key if supported 3246 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3247 #endif 3248 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3249 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3250 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3251 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3252 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3253 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3254 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3255 3256 // set state and send pairing response 3257 sm_timeout_start(connection); 3258 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3259 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3260 break; 3261 3262 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3263 // fill in sm setup (lite version of sm_init_setup) 3264 sm_reset_setup(); 3265 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3266 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3267 setup->sm_s_addr_type = connection->sm_own_addr_type; 3268 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3269 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3270 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3271 setup->sm_use_secure_connections = true; 3272 sm_ctkd_fetch_br_edr_link_key(connection); 3273 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3274 3275 // Enc Key and IRK if requested 3276 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3277 #ifdef ENABLE_LE_SIGNED_WRITE 3278 // Plus signing key if supported 3279 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3280 #endif 3281 // drop flags not requested by initiator 3282 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3283 3284 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3285 // - the IO Capability field, 3286 // - the OOB data flag field, and 3287 // - all bits in the Auth Req field except the CT2 bit. 3288 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3289 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3290 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3291 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3292 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3293 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3294 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3295 3296 // configure key distribution, LTK is derived locally 3297 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3298 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3299 3300 // set state and send pairing response 3301 sm_timeout_start(connection); 3302 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3303 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3304 break; 3305 case SM_BR_EDR_DISTRIBUTE_KEYS: 3306 if (setup->sm_key_distribution_send_set != 0) { 3307 sm_run_distribute_keys(connection); 3308 return; 3309 } 3310 // keys are sent 3311 if (IS_RESPONDER(connection->sm_role)) { 3312 // responder -> receive master keys if there are any 3313 if (!sm_key_distribution_all_received()){ 3314 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3315 break; 3316 } 3317 } 3318 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3319 sm_ctkd_start_from_br_edr(connection); 3320 continue; 3321 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3322 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3323 h6_calculate_ilk_from_le_ltk(connection); 3324 break; 3325 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3326 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3327 h6_calculate_br_edr_link_key(connection); 3328 break; 3329 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3330 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3331 h7_calculate_ilk_from_le_ltk(connection); 3332 break; 3333 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3334 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3335 h6_calculate_ilk_from_br_edr(connection); 3336 break; 3337 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3338 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3339 h6_calculate_le_ltk(connection); 3340 break; 3341 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3342 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3343 h7_calculate_ilk_from_br_edr(connection); 3344 break; 3345 #endif 3346 3347 default: 3348 break; 3349 } 3350 3351 // check again if active connection was released 3352 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3353 } 3354 } 3355 3356 // sm_aes128_state stays active 3357 static void sm_handle_encryption_result_enc_a(void *arg){ 3358 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3359 sm_aes128_state = SM_AES128_IDLE; 3360 3361 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3362 if (connection == NULL) return; 3363 3364 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3365 sm_aes128_state = SM_AES128_ACTIVE; 3366 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); 3367 } 3368 3369 static void sm_handle_encryption_result_enc_b(void *arg){ 3370 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3371 sm_aes128_state = SM_AES128_IDLE; 3372 3373 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3374 if (connection == NULL) return; 3375 3376 log_info_key("c1!", setup->sm_local_confirm); 3377 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3378 sm_trigger_run(); 3379 } 3380 3381 // sm_aes128_state stays active 3382 static void sm_handle_encryption_result_enc_c(void *arg){ 3383 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3384 sm_aes128_state = SM_AES128_IDLE; 3385 3386 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3387 if (connection == NULL) return; 3388 3389 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3390 sm_aes128_state = SM_AES128_ACTIVE; 3391 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); 3392 } 3393 3394 static void sm_handle_encryption_result_enc_d(void * arg){ 3395 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3396 sm_aes128_state = SM_AES128_IDLE; 3397 3398 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3399 if (connection == NULL) return; 3400 3401 log_info_key("c1!", sm_aes128_ciphertext); 3402 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3403 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3404 sm_trigger_run(); 3405 return; 3406 } 3407 if (IS_RESPONDER(connection->sm_role)){ 3408 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3409 sm_trigger_run(); 3410 } else { 3411 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3412 sm_aes128_state = SM_AES128_ACTIVE; 3413 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); 3414 } 3415 } 3416 3417 static void sm_handle_encryption_result_enc_stk(void *arg){ 3418 sm_aes128_state = SM_AES128_IDLE; 3419 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3420 3421 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3422 if (connection == NULL) return; 3423 3424 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3425 log_info_key("stk", setup->sm_ltk); 3426 if (IS_RESPONDER(connection->sm_role)){ 3427 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3428 } else { 3429 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3430 } 3431 sm_trigger_run(); 3432 } 3433 3434 // sm_aes128_state stays active 3435 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3436 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3437 sm_aes128_state = SM_AES128_IDLE; 3438 3439 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3440 if (connection == NULL) return; 3441 3442 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3443 log_info_hex16("y", setup->sm_local_y); 3444 // PH3B3 - calculate EDIV 3445 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3446 log_info_hex16("ediv", setup->sm_local_ediv); 3447 // PH3B4 - calculate LTK - enc 3448 // LTK = d1(ER, DIV, 0)) 3449 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3450 sm_aes128_state = SM_AES128_ACTIVE; 3451 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); 3452 } 3453 3454 #ifdef ENABLE_LE_PERIPHERAL 3455 // sm_aes128_state stays active 3456 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3457 sm_aes128_state = SM_AES128_IDLE; 3458 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3459 3460 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3461 if (connection == NULL) return; 3462 3463 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3464 log_info_hex16("y", setup->sm_local_y); 3465 3466 // PH3B3 - calculate DIV 3467 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3468 log_info_hex16("ediv", setup->sm_local_ediv); 3469 // PH3B4 - calculate LTK - enc 3470 // LTK = d1(ER, DIV, 0)) 3471 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3472 sm_aes128_state = SM_AES128_ACTIVE; 3473 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); 3474 } 3475 #endif 3476 3477 // sm_aes128_state stays active 3478 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3479 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3480 sm_aes128_state = SM_AES128_IDLE; 3481 3482 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3483 if (connection == NULL) return; 3484 3485 log_info_key("ltk", setup->sm_ltk); 3486 // calc CSRK next 3487 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3488 sm_aes128_state = SM_AES128_ACTIVE; 3489 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); 3490 } 3491 3492 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3493 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3494 sm_aes128_state = SM_AES128_IDLE; 3495 3496 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3497 if (connection == NULL) return; 3498 3499 sm_aes128_state = SM_AES128_IDLE; 3500 log_info_key("csrk", setup->sm_local_csrk); 3501 if (setup->sm_key_distribution_send_set != 0u){ 3502 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3503 } else { 3504 // no keys to send, just continue 3505 if (IS_RESPONDER(connection->sm_role)){ 3506 if (sm_key_distribution_all_received()){ 3507 sm_key_distribution_handle_all_received(connection); 3508 sm_key_distribution_complete_responder(connection); 3509 } else { 3510 // slave -> receive master keys 3511 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3512 } 3513 } else { 3514 sm_key_distribution_complete_initiator(connection); 3515 } 3516 } 3517 sm_trigger_run(); 3518 } 3519 3520 #ifdef ENABLE_LE_PERIPHERAL 3521 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3522 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3523 sm_aes128_state = SM_AES128_IDLE; 3524 3525 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3526 if (connection == NULL) return; 3527 3528 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3529 log_info_key("ltk", setup->sm_ltk); 3530 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3531 sm_trigger_run(); 3532 } 3533 #endif 3534 3535 static void sm_handle_encryption_result_address_resolution(void *arg){ 3536 UNUSED(arg); 3537 sm_aes128_state = SM_AES128_IDLE; 3538 3539 // compare calulated address against connecting device 3540 uint8_t * hash = &sm_aes128_ciphertext[13]; 3541 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3542 log_info("LE Device Lookup: matched resolvable private address"); 3543 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3544 sm_trigger_run(); 3545 return; 3546 } 3547 // no match, try next 3548 sm_address_resolution_test++; 3549 sm_trigger_run(); 3550 } 3551 3552 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3553 UNUSED(arg); 3554 sm_aes128_state = SM_AES128_IDLE; 3555 3556 log_info_key("irk", sm_persistent_irk); 3557 dkg_state = DKG_CALC_DHK; 3558 sm_trigger_run(); 3559 } 3560 3561 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3562 UNUSED(arg); 3563 sm_aes128_state = SM_AES128_IDLE; 3564 3565 log_info_key("dhk", sm_persistent_dhk); 3566 dkg_state = DKG_READY; 3567 sm_trigger_run(); 3568 } 3569 3570 static void sm_handle_encryption_result_rau(void *arg){ 3571 UNUSED(arg); 3572 sm_aes128_state = SM_AES128_IDLE; 3573 3574 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3575 rau_state = RAU_IDLE; 3576 hci_le_random_address_set(sm_random_address); 3577 3578 sm_trigger_run(); 3579 } 3580 3581 static void sm_handle_random_result_rau(void * arg){ 3582 UNUSED(arg); 3583 // non-resolvable vs. resolvable 3584 switch (gap_random_adress_type){ 3585 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3586 // resolvable: use random as prand and calc address hash 3587 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3588 sm_random_address[0u] &= 0x3fu; 3589 sm_random_address[0u] |= 0x40u; 3590 rau_state = RAU_GET_ENC; 3591 break; 3592 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3593 default: 3594 // "The two most significant bits of the address shall be equal to ‘0’"" 3595 sm_random_address[0u] &= 0x3fu; 3596 rau_state = RAU_IDLE; 3597 hci_le_random_address_set(sm_random_address); 3598 break; 3599 } 3600 sm_trigger_run(); 3601 } 3602 3603 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3604 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3605 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3606 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3607 if (connection == NULL) return; 3608 3609 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3610 sm_trigger_run(); 3611 } 3612 3613 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3614 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3615 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3616 if (connection == NULL) return; 3617 3618 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3619 sm_trigger_run(); 3620 } 3621 #endif 3622 3623 static void sm_handle_random_result_ph2_random(void * arg){ 3624 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3625 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3626 if (connection == NULL) return; 3627 3628 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3629 sm_trigger_run(); 3630 } 3631 3632 static void sm_handle_random_result_ph2_tk(void * arg){ 3633 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3634 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3635 if (connection == NULL) return; 3636 3637 sm_reset_tk(); 3638 uint32_t tk; 3639 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3640 // map random to 0-999999 without speding much cycles on a modulus operation 3641 tk = little_endian_read_32(sm_random_data,0); 3642 tk = tk & 0xfffff; // 1048575 3643 if (tk >= 999999u){ 3644 tk = tk - 999999u; 3645 } 3646 } else { 3647 // override with pre-defined passkey 3648 tk = sm_fixed_passkey_in_display_role; 3649 } 3650 big_endian_store_32(setup->sm_tk, 12, tk); 3651 if (IS_RESPONDER(connection->sm_role)){ 3652 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3653 } else { 3654 if (setup->sm_use_secure_connections){ 3655 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3656 } else { 3657 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3658 sm_trigger_user_response(connection); 3659 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3660 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3661 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); 3662 } 3663 } 3664 } 3665 sm_trigger_run(); 3666 } 3667 3668 static void sm_handle_random_result_ph3_div(void * arg){ 3669 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3670 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3671 if (connection == NULL) return; 3672 3673 // use 16 bit from random value as div 3674 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3675 log_info_hex16("div", setup->sm_local_div); 3676 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3677 sm_trigger_run(); 3678 } 3679 3680 static void sm_handle_random_result_ph3_random(void * arg){ 3681 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3682 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3683 if (connection == NULL) return; 3684 3685 reverse_64(sm_random_data, setup->sm_local_rand); 3686 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3687 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3688 // no db for authenticated flag hack: store flag in bit 4 of LSB 3689 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3690 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3691 } 3692 static void sm_validate_er_ir(void){ 3693 // warn about default ER/IR 3694 bool warning = false; 3695 if (sm_ir_is_default()){ 3696 warning = true; 3697 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3698 } 3699 if (sm_er_is_default()){ 3700 warning = true; 3701 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3702 } 3703 if (warning) { 3704 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3705 } 3706 } 3707 3708 static void sm_handle_random_result_ir(void *arg){ 3709 sm_persistent_keys_random_active = false; 3710 if (arg != NULL){ 3711 // key generated, store in tlv 3712 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3713 log_info("Generated IR key. Store in TLV status: %d", status); 3714 UNUSED(status); 3715 } 3716 log_info_key("IR", sm_persistent_ir); 3717 dkg_state = DKG_CALC_IRK; 3718 3719 if (test_use_fixed_local_irk){ 3720 log_info_key("IRK", sm_persistent_irk); 3721 dkg_state = DKG_CALC_DHK; 3722 } 3723 3724 sm_trigger_run(); 3725 } 3726 3727 static void sm_handle_random_result_er(void *arg){ 3728 sm_persistent_keys_random_active = false; 3729 if (arg != 0){ 3730 // key generated, store in tlv 3731 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3732 log_info("Generated ER key. Store in TLV status: %d", status); 3733 UNUSED(status); 3734 } 3735 log_info_key("ER", sm_persistent_er); 3736 3737 // try load ir 3738 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3739 if (key_size == 16){ 3740 // ok, let's continue 3741 log_info("IR from TLV"); 3742 sm_handle_random_result_ir( NULL ); 3743 } else { 3744 // invalid, generate new random one 3745 sm_persistent_keys_random_active = true; 3746 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3747 } 3748 } 3749 3750 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){ 3751 3752 // connection info 3753 sm_conn->sm_handle = con_handle; 3754 sm_conn->sm_role = role; 3755 sm_conn->sm_peer_addr_type = addr_type; 3756 memcpy(sm_conn->sm_peer_address, address, 6); 3757 3758 // security properties 3759 sm_conn->sm_connection_encrypted = 0; 3760 sm_conn->sm_connection_authenticated = 0; 3761 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3762 sm_conn->sm_le_db_index = -1; 3763 sm_conn->sm_reencryption_active = false; 3764 3765 // prepare CSRK lookup (does not involve setup) 3766 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3767 3768 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3769 } 3770 3771 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3772 static void sm_event_handle_classic_encryption_event(sm_connection_t * sm_conn, hci_con_handle_t con_handle){ 3773 // CTKD requires BR/EDR Secure Connection 3774 if (sm_conn->sm_connection_encrypted != 2) return; 3775 // prepare for pairing request 3776 if (IS_RESPONDER(sm_conn->sm_role)){ 3777 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3778 } else if (sm_conn->sm_pairing_requested){ 3779 // check if remote supports fixed channels 3780 bool defer = true; 3781 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 3782 if (hci_connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE){ 3783 // check if remote supports SMP over BR/EDR 3784 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 3785 log_info("CTKD: SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST"); 3786 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3787 } else { 3788 defer = false; 3789 } 3790 } else { 3791 // wait for fixed channel info 3792 log_info("CTKD: SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK"); 3793 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK; 3794 } 3795 if (defer){ 3796 hci_dedicated_bonding_defer_disconnect(con_handle, true); 3797 } 3798 } 3799 } 3800 #endif 3801 3802 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3803 3804 UNUSED(channel); // ok: there is no channel 3805 UNUSED(size); // ok: fixed format HCI events 3806 3807 sm_connection_t * sm_conn; 3808 hci_con_handle_t con_handle; 3809 uint8_t status; 3810 bd_addr_t addr; 3811 3812 switch (packet_type) { 3813 3814 case HCI_EVENT_PACKET: 3815 switch (hci_event_packet_get_type(packet)) { 3816 3817 case BTSTACK_EVENT_STATE: 3818 switch (btstack_event_state_get_state(packet)){ 3819 case HCI_STATE_WORKING: 3820 log_info("HCI Working!"); 3821 // setup IR/ER with TLV 3822 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3823 if (sm_tlv_impl != NULL){ 3824 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3825 if (key_size == 16){ 3826 // ok, let's continue 3827 log_info("ER from TLV"); 3828 sm_handle_random_result_er( NULL ); 3829 } else { 3830 // invalid, generate random one 3831 sm_persistent_keys_random_active = true; 3832 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3833 } 3834 } else { 3835 sm_validate_er_ir(); 3836 dkg_state = DKG_CALC_IRK; 3837 3838 if (test_use_fixed_local_irk){ 3839 log_info_key("IRK", sm_persistent_irk); 3840 dkg_state = DKG_CALC_DHK; 3841 } 3842 } 3843 3844 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3845 // trigger ECC key generation 3846 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3847 sm_ec_generate_new_key(); 3848 } 3849 #endif 3850 3851 // restart random address updates after power cycle 3852 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ 3853 gap_random_address_set(sm_random_address); 3854 } else { 3855 gap_random_address_set_mode(gap_random_adress_type); 3856 } 3857 break; 3858 3859 case HCI_STATE_OFF: 3860 case HCI_STATE_HALTING: 3861 log_info("SM: reset state"); 3862 // stop random address update 3863 gap_random_address_update_stop(); 3864 // reset state 3865 sm_state_reset(); 3866 break; 3867 3868 default: 3869 break; 3870 } 3871 break; 3872 3873 #ifdef ENABLE_CLASSIC 3874 case HCI_EVENT_CONNECTION_COMPLETE: 3875 // ignore if connection failed 3876 if (hci_event_connection_complete_get_status(packet)) return; 3877 3878 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3879 sm_conn = sm_get_connection_for_handle(con_handle); 3880 if (!sm_conn) break; 3881 3882 hci_event_connection_complete_get_bd_addr(packet, addr); 3883 sm_connection_init(sm_conn, 3884 con_handle, 3885 (uint8_t) gap_get_role(con_handle), 3886 BD_ADDR_TYPE_LE_PUBLIC, 3887 addr); 3888 // classic connection corresponds to public le address 3889 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3890 gap_local_bd_addr(sm_conn->sm_own_address); 3891 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3892 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3893 break; 3894 #endif 3895 3896 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3897 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3898 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3899 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3900 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3901 if (sm_conn == NULL) break; 3902 sm_conn->sm_pairing_requested = true; 3903 break; 3904 #endif 3905 3906 case HCI_EVENT_META_GAP: 3907 switch (hci_event_gap_meta_get_subevent_code(packet)) { 3908 case GAP_SUBEVENT_LE_CONNECTION_COMPLETE: 3909 // ignore if connection failed 3910 if (gap_subevent_le_connection_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3911 3912 con_handle = gap_subevent_le_connection_complete_get_connection_handle(packet); 3913 sm_conn = sm_get_connection_for_handle(con_handle); 3914 if (!sm_conn) break; 3915 3916 gap_subevent_le_connection_complete_get_peer_address(packet, addr); 3917 sm_connection_init(sm_conn, 3918 con_handle, 3919 gap_subevent_le_connection_complete_get_role(packet), 3920 gap_subevent_le_connection_complete_get_peer_address_type(packet), 3921 addr); 3922 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3923 3924 // track our addr used for this connection and set state 3925 #ifdef ENABLE_LE_PERIPHERAL 3926 if (gap_subevent_le_connection_complete_get_role(packet) != 0){ 3927 // responder - use own address from advertisements 3928 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3929 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3930 } 3931 #endif 3932 #ifdef ENABLE_LE_CENTRAL 3933 if (gap_subevent_le_connection_complete_get_role(packet) == 0){ 3934 // initiator - use own address from create connection 3935 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3936 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3937 } 3938 #endif 3939 break; 3940 default: 3941 break; 3942 } 3943 break; 3944 case HCI_EVENT_LE_META: 3945 switch (hci_event_le_meta_get_subevent_code(packet)) { 3946 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3947 con_handle = hci_subevent_le_long_term_key_request_get_connection_handle(packet); 3948 sm_conn = sm_get_connection_for_handle(con_handle); 3949 if (!sm_conn) break; 3950 3951 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3952 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3953 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3954 break; 3955 } 3956 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3957 // PH2 SEND LTK as we need to exchange keys in PH3 3958 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3959 break; 3960 } 3961 3962 // store rand and ediv 3963 reverse_64(&packet[5], sm_conn->sm_local_rand); 3964 sm_conn->sm_local_ediv = hci_subevent_le_long_term_key_request_get_encryption_diversifier(packet); 3965 3966 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3967 // potentially stored LTK is from the master 3968 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3969 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3970 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3971 break; 3972 } 3973 // additionally check if remote is in LE Device DB if requested 3974 switch(sm_conn->sm_irk_lookup_state){ 3975 case IRK_LOOKUP_FAILED: 3976 log_info("LTK Request: device not in device db"); 3977 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3978 break; 3979 case IRK_LOOKUP_SUCCEEDED: 3980 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3981 break; 3982 default: 3983 // wait for irk look doen 3984 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3985 break; 3986 } 3987 break; 3988 } 3989 3990 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3991 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3992 #else 3993 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3994 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3995 #endif 3996 break; 3997 3998 default: 3999 break; 4000 } 4001 break; 4002 4003 case HCI_EVENT_ENCRYPTION_CHANGE: 4004 case HCI_EVENT_ENCRYPTION_CHANGE_V2: 4005 con_handle = hci_event_encryption_change_get_connection_handle(packet); 4006 sm_conn = sm_get_connection_for_handle(con_handle); 4007 if (!sm_conn) break; 4008 4009 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 4010 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 4011 sm_conn->sm_actual_encryption_key_size); 4012 log_info("event handler, state %u", sm_conn->sm_engine_state); 4013 4014 switch (sm_conn->sm_engine_state){ 4015 4016 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4017 // encryption change event concludes re-encryption for bonded devices (even if it fails) 4018 if (sm_conn->sm_connection_encrypted != 0u) { 4019 status = ERROR_CODE_SUCCESS; 4020 if (IS_RESPONDER(sm_conn->sm_role)){ 4021 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4022 } else { 4023 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4024 } 4025 } else { 4026 status = hci_event_encryption_change_get_status(packet); 4027 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 4028 // also, gap_reconnect_security_setup_active will return true 4029 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 4030 } 4031 4032 // emit re-encryption complete 4033 sm_reencryption_complete(sm_conn, status); 4034 4035 // notify client, if pairing was requested before 4036 if (sm_conn->sm_pairing_requested){ 4037 sm_conn->sm_pairing_requested = false; 4038 sm_pairing_complete(sm_conn, status, 0); 4039 } 4040 4041 sm_done_for_handle(sm_conn->sm_handle); 4042 break; 4043 4044 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4045 if (!sm_conn->sm_connection_encrypted) break; 4046 // handler for HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE 4047 // contains the same code for this state 4048 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 4049 if (IS_RESPONDER(sm_conn->sm_role)){ 4050 // slave 4051 if (sm_conn->sm_connection_sc){ 4052 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4053 } else { 4054 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); 4055 } 4056 } else { 4057 // master 4058 if (sm_key_distribution_all_received()){ 4059 // skip receiving keys as there are none 4060 sm_key_distribution_handle_all_received(sm_conn); 4061 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); 4062 } else { 4063 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4064 } 4065 } 4066 break; 4067 4068 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4069 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4070 sm_event_handle_classic_encryption_event(sm_conn, con_handle); 4071 break; 4072 #endif 4073 default: 4074 break; 4075 } 4076 break; 4077 4078 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 4079 con_handle = little_endian_read_16(packet, 3); 4080 sm_conn = sm_get_connection_for_handle(con_handle); 4081 if (!sm_conn) break; 4082 4083 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 4084 log_info("event handler, state %u", sm_conn->sm_engine_state); 4085 // continue if part of initial pairing 4086 switch (sm_conn->sm_engine_state){ 4087 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4088 if (IS_RESPONDER(sm_conn->sm_role)){ 4089 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4090 } else { 4091 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4092 } 4093 sm_done_for_handle(sm_conn->sm_handle); 4094 break; 4095 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4096 // handler for HCI_EVENT_ENCRYPTION_CHANGE 4097 // contains the same code for this state 4098 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 4099 if (IS_RESPONDER(sm_conn->sm_role)){ 4100 // slave 4101 if (sm_conn->sm_connection_sc){ 4102 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4103 } else { 4104 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); 4105 } 4106 } else { 4107 // master 4108 if (sm_key_distribution_all_received()){ 4109 // skip receiving keys as there are none 4110 sm_key_distribution_handle_all_received(sm_conn); 4111 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); 4112 } else { 4113 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4114 } 4115 } 4116 break; 4117 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4118 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4119 sm_event_handle_classic_encryption_event(sm_conn, con_handle); 4120 break; 4121 #endif 4122 default: 4123 break; 4124 } 4125 break; 4126 4127 4128 case HCI_EVENT_DISCONNECTION_COMPLETE: 4129 con_handle = little_endian_read_16(packet, 3); 4130 sm_done_for_handle(con_handle); 4131 sm_conn = sm_get_connection_for_handle(con_handle); 4132 if (!sm_conn) break; 4133 4134 // pairing failed, if it was ongoing 4135 switch (sm_conn->sm_engine_state){ 4136 case SM_GENERAL_IDLE: 4137 case SM_INITIATOR_CONNECTED: 4138 case SM_RESPONDER_IDLE: 4139 break; 4140 default: 4141 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 4142 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 4143 break; 4144 } 4145 4146 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 4147 sm_conn->sm_handle = 0; 4148 break; 4149 4150 case HCI_EVENT_COMMAND_COMPLETE: 4151 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 4152 // set local addr for le device db 4153 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 4154 le_device_db_set_local_bd_addr(addr); 4155 } 4156 break; 4157 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4158 case L2CAP_EVENT_INFORMATION_RESPONSE: 4159 con_handle = l2cap_event_information_response_get_con_handle(packet); 4160 sm_conn = sm_get_connection_for_handle(con_handle); 4161 if (!sm_conn) break; 4162 if (sm_conn->sm_engine_state == SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK){ 4163 // check if remote supports SMP over BR/EDR 4164 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 4165 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 4166 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 4167 } else { 4168 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4169 hci_dedicated_bonding_defer_disconnect(con_handle, false); 4170 } 4171 } 4172 break; 4173 #endif 4174 default: 4175 break; 4176 } 4177 break; 4178 default: 4179 break; 4180 } 4181 4182 sm_run(); 4183 } 4184 4185 static inline int sm_calc_actual_encryption_key_size(int other){ 4186 if (other < sm_min_encryption_key_size) return 0; 4187 if (other < sm_max_encryption_key_size) return other; 4188 return sm_max_encryption_key_size; 4189 } 4190 4191 4192 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4193 static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 4194 switch (method){ 4195 case JUST_WORKS: 4196 case NUMERIC_COMPARISON: 4197 return true; 4198 default: 4199 return false; 4200 } 4201 } 4202 // responder 4203 4204 static bool sm_passkey_used(stk_generation_method_t method){ 4205 switch (method){ 4206 case PK_RESP_INPUT: 4207 return true; 4208 default: 4209 return 0; 4210 } 4211 } 4212 4213 static bool sm_passkey_entry(stk_generation_method_t method){ 4214 switch (method){ 4215 case PK_RESP_INPUT: 4216 case PK_INIT_INPUT: 4217 case PK_BOTH_INPUT: 4218 return true; 4219 default: 4220 return false; 4221 } 4222 } 4223 4224 #endif 4225 4226 /** 4227 * @return ok 4228 */ 4229 static int sm_validate_stk_generation_method(void){ 4230 // check if STK generation method is acceptable by client 4231 switch (setup->sm_stk_generation_method){ 4232 case JUST_WORKS: 4233 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4234 case PK_RESP_INPUT: 4235 case PK_INIT_INPUT: 4236 case PK_BOTH_INPUT: 4237 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4238 case OOB: 4239 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4240 case NUMERIC_COMPARISON: 4241 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4242 default: 4243 return 0; 4244 } 4245 } 4246 4247 #ifdef ENABLE_LE_CENTRAL 4248 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4250 if (sm_sc_only_mode){ 4251 uint8_t auth_req = packet[1]; 4252 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4253 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4254 return; 4255 } 4256 } 4257 #else 4258 UNUSED(packet); 4259 #endif 4260 4261 int have_ltk; 4262 uint8_t ltk[16]; 4263 4264 // IRK complete? 4265 switch (sm_conn->sm_irk_lookup_state){ 4266 case IRK_LOOKUP_FAILED: 4267 // start pairing 4268 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4269 break; 4270 case IRK_LOOKUP_SUCCEEDED: 4271 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4272 have_ltk = !sm_is_null_key(ltk); 4273 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4274 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4275 // start re-encrypt if we have LTK and the connection is not already encrypted 4276 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4277 } else { 4278 // start pairing 4279 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4280 } 4281 break; 4282 default: 4283 // otherwise, store security request 4284 sm_conn->sm_security_request_received = true; 4285 break; 4286 } 4287 } 4288 #endif 4289 4290 static uint8_t sm_pdu_validate_and_get_opcode(uint8_t packet_type, const uint8_t *packet, uint16_t size){ 4291 4292 // size of complete sm_pdu used to validate input 4293 static const uint8_t sm_pdu_size[] = { 4294 0, // 0x00 invalid opcode 4295 7, // 0x01 pairing request 4296 7, // 0x02 pairing response 4297 17, // 0x03 pairing confirm 4298 17, // 0x04 pairing random 4299 2, // 0x05 pairing failed 4300 17, // 0x06 encryption information 4301 11, // 0x07 master identification 4302 17, // 0x08 identification information 4303 8, // 0x09 identify address information 4304 17, // 0x0a signing information 4305 2, // 0x0b security request 4306 65, // 0x0c pairing public key 4307 17, // 0x0d pairing dhk check 4308 2, // 0x0e keypress notification 4309 }; 4310 4311 if (packet_type != SM_DATA_PACKET) return 0; 4312 if (size == 0u) return 0; 4313 4314 uint8_t sm_pdu_code = packet[0]; 4315 4316 // validate pdu size 4317 if (sm_pdu_code >= sizeof(sm_pdu_size)) return 0; 4318 if (sm_pdu_size[sm_pdu_code] != size) return 0; 4319 4320 return sm_pdu_code; 4321 } 4322 4323 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4324 4325 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4326 sm_run(); 4327 } 4328 4329 uint8_t sm_pdu_code = sm_pdu_validate_and_get_opcode(packet_type, packet, size); 4330 if (sm_pdu_code == 0) return; 4331 4332 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4333 if (!sm_conn) return; 4334 4335 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4336 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4337 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4338 sm_done_for_handle(con_handle); 4339 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4340 return; 4341 } 4342 4343 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4344 4345 int err; 4346 uint8_t max_encryption_key_size; 4347 UNUSED(err); 4348 4349 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4350 uint8_t buffer[5]; 4351 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4352 buffer[1] = 3; 4353 little_endian_store_16(buffer, 2, con_handle); 4354 buffer[4] = packet[1]; 4355 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4356 return; 4357 } 4358 4359 switch (sm_conn->sm_engine_state){ 4360 4361 // a sm timeout requires a new physical connection 4362 case SM_GENERAL_TIMEOUT: 4363 return; 4364 4365 #ifdef ENABLE_LE_CENTRAL 4366 4367 // Initiator 4368 case SM_INITIATOR_CONNECTED: 4369 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4370 sm_pdu_received_in_wrong_state(sm_conn); 4371 break; 4372 } 4373 sm_initiator_connected_handle_security_request(sm_conn, packet); 4374 break; 4375 4376 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4377 // Core 5, Vol 3, Part H, 2.4.6: 4378 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4379 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4380 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4381 log_info("Ignoring Security Request"); 4382 break; 4383 } 4384 4385 // all other pdus are incorrect 4386 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4387 sm_pdu_received_in_wrong_state(sm_conn); 4388 break; 4389 } 4390 4391 // store pairing request 4392 (void)memcpy(&setup->sm_s_pres, packet, 4393 sizeof(sm_pairing_packet_t)); 4394 4395 // validate encryption key size 4396 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); 4397 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4398 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4399 break; 4400 } 4401 4402 err = sm_stk_generation_init(sm_conn); 4403 4404 #ifdef ENABLE_TESTING_SUPPORT 4405 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4406 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4407 err = test_pairing_failure; 4408 } 4409 #endif 4410 4411 if (err != 0){ 4412 sm_pairing_error(sm_conn, err); 4413 break; 4414 } 4415 4416 // generate random number first, if we need to show passkey 4417 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4418 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); 4419 break; 4420 } 4421 4422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4423 if (setup->sm_use_secure_connections){ 4424 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4425 if (setup->sm_stk_generation_method == JUST_WORKS){ 4426 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4427 sm_trigger_user_response(sm_conn); 4428 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4429 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4430 } 4431 } else { 4432 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4433 } 4434 break; 4435 } 4436 #endif 4437 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4438 sm_trigger_user_response(sm_conn); 4439 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4440 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4441 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); 4442 } 4443 break; 4444 4445 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4446 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4447 sm_pdu_received_in_wrong_state(sm_conn); 4448 break; 4449 } 4450 4451 // store s_confirm 4452 reverse_128(&packet[1], setup->sm_peer_confirm); 4453 4454 // abort if s_confirm matches m_confirm 4455 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4456 sm_pdu_received_in_wrong_state(sm_conn); 4457 break; 4458 } 4459 4460 #ifdef ENABLE_TESTING_SUPPORT 4461 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4462 log_info("testing_support: reset confirm value"); 4463 memset(setup->sm_peer_confirm, 0, 16); 4464 } 4465 #endif 4466 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4467 break; 4468 4469 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4470 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4471 sm_pdu_received_in_wrong_state(sm_conn); 4472 break;; 4473 } 4474 4475 // received random value 4476 reverse_128(&packet[1], setup->sm_peer_random); 4477 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4478 break; 4479 4480 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4481 // ignore Security Request, see SM_INITIATOR_PH1_W4_PAIRING_RESPONSE above 4482 if (sm_pdu_code != SM_CODE_SECURITY_REQUEST){ 4483 sm_pdu_received_in_wrong_state(sm_conn); 4484 } 4485 break; 4486 #endif 4487 4488 #ifdef ENABLE_LE_PERIPHERAL 4489 // Responder 4490 case SM_RESPONDER_IDLE: 4491 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4492 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4493 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4494 sm_pdu_received_in_wrong_state(sm_conn); 4495 break;; 4496 } 4497 4498 // store pairing request 4499 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4500 4501 // validation encryption key size 4502 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); 4503 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4504 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4505 break; 4506 } 4507 4508 // check if IRK completed 4509 switch (sm_conn->sm_irk_lookup_state){ 4510 case IRK_LOOKUP_SUCCEEDED: 4511 case IRK_LOOKUP_FAILED: 4512 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4513 break; 4514 default: 4515 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4516 break; 4517 } 4518 break; 4519 #endif 4520 4521 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4522 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4523 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4524 sm_pdu_received_in_wrong_state(sm_conn); 4525 break; 4526 } 4527 4528 // store public key for DH Key calculation 4529 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4530 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4531 4532 // CVE-2020-26558: abort pairing if remote uses the same public key 4533 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4534 log_info("Remote PK matches ours"); 4535 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4536 break; 4537 } 4538 4539 // validate public key 4540 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4541 if (err != 0){ 4542 log_info("sm: peer public key invalid %x", err); 4543 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4544 break; 4545 } 4546 4547 // start calculating dhkey 4548 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); 4549 4550 4551 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4552 if (IS_RESPONDER(sm_conn->sm_role)){ 4553 // responder 4554 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4555 } else { 4556 // initiator 4557 // stk generation method 4558 // passkey entry: notify app to show passkey or to request passkey 4559 switch (setup->sm_stk_generation_method){ 4560 case JUST_WORKS: 4561 case NUMERIC_COMPARISON: 4562 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4563 break; 4564 case PK_RESP_INPUT: 4565 sm_sc_start_calculating_local_confirm(sm_conn); 4566 break; 4567 case PK_INIT_INPUT: 4568 case PK_BOTH_INPUT: 4569 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4570 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4571 break; 4572 } 4573 sm_sc_start_calculating_local_confirm(sm_conn); 4574 break; 4575 case OOB: 4576 // generate Nx 4577 log_info("Generate Na"); 4578 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); 4579 break; 4580 default: 4581 btstack_assert(false); 4582 break; 4583 } 4584 } 4585 break; 4586 4587 case SM_SC_W4_CONFIRMATION: 4588 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4589 sm_pdu_received_in_wrong_state(sm_conn); 4590 break; 4591 } 4592 // received confirm value 4593 reverse_128(&packet[1], setup->sm_peer_confirm); 4594 4595 #ifdef ENABLE_TESTING_SUPPORT 4596 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4597 log_info("testing_support: reset confirm value"); 4598 memset(setup->sm_peer_confirm, 0, 16); 4599 } 4600 #endif 4601 if (IS_RESPONDER(sm_conn->sm_role)){ 4602 // responder 4603 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4604 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4605 // still waiting for passkey 4606 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4607 break; 4608 } 4609 } 4610 sm_sc_start_calculating_local_confirm(sm_conn); 4611 } else { 4612 // initiator 4613 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4614 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); 4615 } else { 4616 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4617 } 4618 } 4619 break; 4620 4621 case SM_SC_W4_PAIRING_RANDOM: 4622 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4623 sm_pdu_received_in_wrong_state(sm_conn); 4624 break; 4625 } 4626 4627 // received random value 4628 reverse_128(&packet[1], setup->sm_peer_nonce); 4629 4630 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4631 // only check for JUST WORK/NC in initiator role OR passkey entry 4632 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4633 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4634 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4635 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4636 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4637 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4638 break; 4639 } 4640 4641 // OOB 4642 if (setup->sm_stk_generation_method == OOB){ 4643 4644 // setup local random, set to zero if remote did not receive our data 4645 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4646 if (IS_RESPONDER(sm_conn->sm_role)){ 4647 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4648 log_info("Reset rb as A does not have OOB data"); 4649 memset(setup->sm_rb, 0, 16); 4650 } else { 4651 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4652 log_info("Use stored rb"); 4653 log_info_hexdump(setup->sm_rb, 16); 4654 } 4655 } else { 4656 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4657 log_info("Reset ra as B does not have OOB data"); 4658 memset(setup->sm_ra, 0, 16); 4659 } else { 4660 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4661 log_info("Use stored ra"); 4662 log_info_hexdump(setup->sm_ra, 16); 4663 } 4664 } 4665 4666 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4667 if (setup->sm_have_oob_data){ 4668 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4669 break; 4670 } 4671 } 4672 4673 // TODO: we only get here for Responder role with JW/NC 4674 sm_sc_state_after_receiving_random(sm_conn); 4675 break; 4676 4677 case SM_SC_W2_CALCULATE_G2: 4678 case SM_SC_W4_CALCULATE_G2: 4679 case SM_SC_W4_CALCULATE_DHKEY: 4680 case SM_SC_W2_CALCULATE_F5_SALT: 4681 case SM_SC_W4_CALCULATE_F5_SALT: 4682 case SM_SC_W2_CALCULATE_F5_MACKEY: 4683 case SM_SC_W4_CALCULATE_F5_MACKEY: 4684 case SM_SC_W2_CALCULATE_F5_LTK: 4685 case SM_SC_W4_CALCULATE_F5_LTK: 4686 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4687 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4688 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4689 case SM_SC_W4_USER_RESPONSE: 4690 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4691 sm_pdu_received_in_wrong_state(sm_conn); 4692 break; 4693 } 4694 // store DHKey Check 4695 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4696 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4697 4698 // have we been only waiting for dhkey check command? 4699 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4700 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4701 } 4702 break; 4703 #endif 4704 4705 #ifdef ENABLE_LE_PERIPHERAL 4706 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4707 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4708 sm_pdu_received_in_wrong_state(sm_conn); 4709 break; 4710 } 4711 4712 // received confirm value 4713 reverse_128(&packet[1], setup->sm_peer_confirm); 4714 4715 #ifdef ENABLE_TESTING_SUPPORT 4716 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4717 log_info("testing_support: reset confirm value"); 4718 memset(setup->sm_peer_confirm, 0, 16); 4719 } 4720 #endif 4721 // notify client to hide shown passkey 4722 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4723 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4724 } 4725 4726 // handle user cancel pairing? 4727 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4728 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4729 break; 4730 } 4731 4732 // wait for user action? 4733 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4734 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4735 break; 4736 } 4737 4738 // calculate and send local_confirm 4739 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); 4740 break; 4741 4742 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4743 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4744 sm_pdu_received_in_wrong_state(sm_conn); 4745 break;; 4746 } 4747 4748 // received random value 4749 reverse_128(&packet[1], setup->sm_peer_random); 4750 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4751 break; 4752 #endif 4753 4754 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4755 case SM_PH3_RECEIVE_KEYS: 4756 switch(sm_pdu_code){ 4757 case SM_CODE_ENCRYPTION_INFORMATION: 4758 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4759 reverse_128(&packet[1], setup->sm_peer_ltk); 4760 break; 4761 4762 case SM_CODE_MASTER_IDENTIFICATION: 4763 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4764 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4765 reverse_64(&packet[3], setup->sm_peer_rand); 4766 break; 4767 4768 case SM_CODE_IDENTITY_INFORMATION: 4769 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4770 reverse_128(&packet[1], setup->sm_peer_irk); 4771 break; 4772 4773 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4774 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4775 setup->sm_peer_addr_type = packet[1]; 4776 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4777 break; 4778 4779 case SM_CODE_SIGNING_INFORMATION: 4780 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4781 reverse_128(&packet[1], setup->sm_peer_csrk); 4782 break; 4783 default: 4784 // Unexpected PDU 4785 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4786 break; 4787 } 4788 // done with key distribution? 4789 if (sm_key_distribution_all_received()){ 4790 4791 sm_key_distribution_handle_all_received(sm_conn); 4792 4793 if (IS_RESPONDER(sm_conn->sm_role)){ 4794 sm_key_distribution_complete_responder(sm_conn); 4795 } else { 4796 if (setup->sm_use_secure_connections){ 4797 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4798 } else { 4799 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); 4800 } 4801 } 4802 } 4803 break; 4804 4805 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4806 4807 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4808 // GAP/DM/LEP/BI-02-C - reject CTKD if P-192 encryption is used 4809 if (sm_pdu_code == SM_CODE_PAIRING_REQUEST){ 4810 sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); 4811 } 4812 break; 4813 4814 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4815 4816 // dedicated bonding complete 4817 hci_dedicated_bonding_defer_disconnect(sm_conn->sm_handle, false); 4818 4819 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4820 sm_pdu_received_in_wrong_state(sm_conn); 4821 break; 4822 } 4823 // store pairing response 4824 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4825 4826 // validate encryption key size 4827 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); 4828 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4829 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4830 break; 4831 } 4832 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); 4833 // SC Only mandates 128 bit key size 4834 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4835 sm_conn->sm_actual_encryption_key_size = 0; 4836 } 4837 if (sm_conn->sm_actual_encryption_key_size == 0){ 4838 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4839 break; 4840 } 4841 4842 // prepare key exchange, LTK is derived locally 4843 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4844 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4845 4846 // skip receive if there are none 4847 if (sm_key_distribution_all_received()){ 4848 // distribute keys in run handles 'no keys to send' 4849 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4850 } else { 4851 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4852 } 4853 break; 4854 4855 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4856 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4857 sm_pdu_received_in_wrong_state(sm_conn); 4858 break; 4859 } 4860 4861 // store pairing request 4862 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4863 4864 // validate encryption key size 4865 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_m_preq); 4866 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4867 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4868 break; 4869 } 4870 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); 4871 // SC Only mandates 128 bit key size 4872 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4873 sm_conn->sm_actual_encryption_key_size = 0; 4874 } 4875 if (sm_conn->sm_actual_encryption_key_size == 0){ 4876 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4877 break; 4878 } 4879 // trigger response 4880 if (sm_ctkd_from_classic(sm_conn)){ 4881 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4882 } else { 4883 sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); 4884 } 4885 break; 4886 4887 case SM_BR_EDR_RECEIVE_KEYS: 4888 switch(sm_pdu_code){ 4889 case SM_CODE_IDENTITY_INFORMATION: 4890 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4891 reverse_128(&packet[1], setup->sm_peer_irk); 4892 break; 4893 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4894 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4895 setup->sm_peer_addr_type = packet[1]; 4896 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4897 break; 4898 case SM_CODE_SIGNING_INFORMATION: 4899 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4900 reverse_128(&packet[1], setup->sm_peer_csrk); 4901 break; 4902 default: 4903 // Unexpected PDU 4904 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4905 break; 4906 } 4907 4908 // all keys received 4909 if (sm_key_distribution_all_received()){ 4910 if (IS_RESPONDER(sm_conn->sm_role)){ 4911 // responder -> keys exchanged, derive LE LTK 4912 sm_ctkd_start_from_br_edr(sm_conn); 4913 } else { 4914 // initiator -> send our keys if any 4915 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4916 } 4917 } 4918 break; 4919 #endif 4920 4921 default: 4922 // Unexpected PDU 4923 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4924 sm_pdu_received_in_wrong_state(sm_conn); 4925 break; 4926 } 4927 4928 // try to send next pdu 4929 sm_trigger_run(); 4930 } 4931 4932 // Security Manager Client API 4933 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4934 sm_get_oob_data = get_oob_data_callback; 4935 } 4936 4937 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)){ 4938 sm_get_sc_oob_data = get_sc_oob_data_callback; 4939 } 4940 4941 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)){ 4942 sm_get_ltk_callback = get_ltk_callback; 4943 } 4944 4945 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4946 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4947 } 4948 4949 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4950 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4951 } 4952 4953 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4954 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4955 } 4956 4957 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4958 sm_min_encryption_key_size = min_size; 4959 sm_max_encryption_key_size = max_size; 4960 } 4961 4962 void sm_set_authentication_requirements(uint8_t auth_req){ 4963 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4964 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4965 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4966 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4967 } 4968 #endif 4969 sm_auth_req = auth_req; 4970 } 4971 4972 void sm_set_io_capabilities(io_capability_t io_capability){ 4973 sm_io_capabilities = io_capability; 4974 } 4975 4976 #ifdef ENABLE_LE_PERIPHERAL 4977 void sm_set_request_security(bool enable){ 4978 sm_slave_request_security = enable; 4979 } 4980 #endif 4981 4982 void sm_set_er(sm_key_t er){ 4983 (void)memcpy(sm_persistent_er, er, 16); 4984 } 4985 4986 void sm_set_ir(sm_key_t ir){ 4987 (void)memcpy(sm_persistent_ir, ir, 16); 4988 } 4989 4990 // Testing support only 4991 void sm_test_set_irk(sm_key_t irk){ 4992 (void)memcpy(sm_persistent_irk, irk, 16); 4993 dkg_state = DKG_CALC_DHK; 4994 test_use_fixed_local_irk = true; 4995 } 4996 4997 void sm_test_use_fixed_local_csrk(void){ 4998 test_use_fixed_local_csrk = true; 4999 } 5000 5001 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5002 static void sm_ec_generated(void * arg){ 5003 UNUSED(arg); 5004 ec_key_generation_state = EC_KEY_GENERATION_DONE; 5005 // trigger pairing if pending for ec key 5006 sm_trigger_run(); 5007 } 5008 static void sm_ec_generate_new_key(void) { 5009 log_info("sm: generate new ec key"); 5010 #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY 5011 // LE Secure Connections Debug Key 5012 const uint8_t debug_key_public[64] = { 5013 0x20, 0xb0, 0x03, 0xd2, 0xf2, 0x97, 0xbe, 0x2c, 0x5e, 0x2c, 0x83, 0xa7, 0xe9, 0xf9, 0xa5, 0xb9, 5014 0xef, 0xf4, 0x91, 0x11, 0xac, 0xf4, 0xfd, 0xdb, 0xcc, 0x03, 0x01, 0x48, 0x0e, 0x35, 0x9d, 0xe6, 5015 0xdc, 0x80, 0x9c, 0x49, 0x65, 0x2a, 0xeb, 0x6d, 0x63, 0x32, 0x9a, 0xbf, 0x5a, 0x52, 0x15, 0x5c, 5016 0x76, 0x63, 0x45, 0xc2, 0x8f, 0xed, 0x30, 0x24, 0x74, 0x1c, 0x8e, 0xd0, 0x15, 0x89, 0xd2, 0x8b 5017 }; 5018 const uint8_t debug_key_private[32] = { 5019 0x3f, 0x49, 0xf6, 0xd4, 0xa3, 0xc5, 0x5f, 0x38, 0x74, 0xc9, 0xb3, 0xe3, 0xd2, 0x10, 0x3f, 0x50, 5020 0x4a, 0xff, 0x60, 0x7b, 0xeb, 0x40, 0xb7, 0x99, 0x58, 0x99, 0xb8, 0xa6, 0xcd, 0x3c, 0x1a, 0xbd 5021 }; 5022 if (sm_sc_debug_keys_enabled) { 5023 memcpy(ec_q, debug_key_public, 64); 5024 btstack_crypto_ecc_p256_set_key(debug_key_public, debug_key_private); 5025 ec_key_generation_state = EC_KEY_GENERATION_DONE; 5026 } else 5027 #endif 5028 { 5029 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 5030 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 5031 } 5032 } 5033 #endif 5034 5035 #ifdef ENABLE_TESTING_SUPPORT 5036 void sm_test_set_pairing_failure(int reason){ 5037 test_pairing_failure = reason; 5038 } 5039 #endif 5040 5041 static void sm_state_reset(void) { 5042 #ifdef USE_CMAC_ENGINE 5043 sm_cmac_active = 0; 5044 #endif 5045 dkg_state = DKG_W4_WORKING; 5046 rau_state = RAU_IDLE; 5047 sm_aes128_state = SM_AES128_IDLE; 5048 sm_address_resolution_test = -1; // no private address to resolve yet 5049 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 5050 sm_address_resolution_general_queue = NULL; 5051 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 5052 sm_persistent_keys_random_active = false; 5053 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5054 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 5055 #endif 5056 } 5057 5058 void sm_init(void){ 5059 5060 if (sm_initialized) return; 5061 5062 // set default ER and IR values (should be unique - set by app or sm later using TLV) 5063 sm_er_ir_set_default(); 5064 5065 // defaults 5066 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 5067 | SM_STK_GENERATION_METHOD_OOB 5068 | SM_STK_GENERATION_METHOD_PASSKEY 5069 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 5070 5071 sm_max_encryption_key_size = 16; 5072 sm_min_encryption_key_size = 7; 5073 5074 sm_fixed_passkey_in_display_role = 0xffffffffU; 5075 sm_reconstruct_ltk_without_le_device_db_entry = true; 5076 5077 gap_random_adress_update_period = 15 * 60 * 1000L; 5078 5079 test_use_fixed_local_csrk = false; 5080 5081 // other 5082 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 5083 5084 // register for HCI Events 5085 hci_event_callback_registration.callback = &sm_event_packet_handler; 5086 hci_add_event_handler(&hci_event_callback_registration); 5087 5088 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 5089 // register for L2CAP events 5090 l2cap_event_callback_registration.callback = &sm_event_packet_handler; 5091 l2cap_add_event_handler(&l2cap_event_callback_registration); 5092 #endif 5093 5094 // 5095 btstack_crypto_init(); 5096 5097 // init le_device_db 5098 le_device_db_init(); 5099 5100 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 5101 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 5102 #ifdef ENABLE_CLASSIC 5103 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); 5104 #endif 5105 5106 // state 5107 sm_state_reset(); 5108 5109 sm_initialized = true; 5110 } 5111 5112 void sm_deinit(void){ 5113 sm_initialized = false; 5114 btstack_run_loop_remove_timer(&sm_run_timer); 5115 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) 5116 sm_sc_debug_keys_enabled = false; 5117 #endif 5118 } 5119 5120 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 5121 sm_fixed_passkey_in_display_role = passkey; 5122 } 5123 5124 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 5125 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 5126 } 5127 5128 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 5129 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 5130 if (!hci_con) return NULL; 5131 return &hci_con->sm_connection; 5132 } 5133 5134 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk){ 5135 hci_connection_t * hci_con = hci_connection_for_handle(connection->sm_handle); 5136 btstack_assert(hci_con != NULL); 5137 memcpy(hci_con->link_key, ltk, 16); 5138 hci_con->link_key_type = 1; 5139 } 5140 5141 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 5142 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 5143 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 5144 if (!hci_con) return NULL; 5145 return &hci_con->sm_connection; 5146 } 5147 #endif 5148 5149 // @deprecated: map onto sm_request_pairing 5150 void sm_send_security_request(hci_con_handle_t con_handle){ 5151 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5152 if (!sm_conn) return; 5153 if (!IS_RESPONDER(sm_conn->sm_role)) return; 5154 sm_request_pairing(con_handle); 5155 } 5156 5157 // request pairing 5158 void sm_request_pairing(hci_con_handle_t con_handle){ 5159 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5160 if (!sm_conn) return; // wrong connection 5161 5162 bool have_ltk; 5163 uint8_t ltk[16]; 5164 bool auth_required; 5165 int authenticated; 5166 bool trigger_reencryption; 5167 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 5168 if (IS_RESPONDER(sm_conn->sm_role)){ 5169 switch (sm_conn->sm_engine_state){ 5170 case SM_GENERAL_IDLE: 5171 case SM_RESPONDER_IDLE: 5172 switch (sm_conn->sm_irk_lookup_state){ 5173 case IRK_LOOKUP_SUCCEEDED: 5174 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 5175 have_ltk = !sm_is_null_key(ltk); 5176 log_info("have ltk %u", have_ltk); 5177 if (have_ltk){ 5178 sm_conn->sm_pairing_requested = true; 5179 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5180 sm_reencryption_started(sm_conn); 5181 break; 5182 } 5183 /* fall through */ 5184 5185 case IRK_LOOKUP_FAILED: 5186 sm_conn->sm_pairing_requested = true; 5187 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5188 sm_pairing_started(sm_conn); 5189 break; 5190 default: 5191 log_info("irk lookup pending"); 5192 sm_conn->sm_pairing_requested = true; 5193 break; 5194 } 5195 break; 5196 default: 5197 break; 5198 } 5199 } else { 5200 // used as a trigger to start central/master/initiator security procedures 5201 switch (sm_conn->sm_engine_state){ 5202 case SM_INITIATOR_CONNECTED: 5203 switch (sm_conn->sm_irk_lookup_state){ 5204 case IRK_LOOKUP_SUCCEEDED: 5205 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); 5206 have_ltk = !sm_is_null_key(ltk); 5207 auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; 5208 // re-encrypt is sufficient if we have ltk and that is either already authenticated or we don't require authentication 5209 trigger_reencryption = have_ltk && ((authenticated != 0) || (auth_required == false)); 5210 log_info("have ltk %u, authenticated %u, auth required %u => reencrypt %u", have_ltk, authenticated, auth_required, trigger_reencryption); 5211 if (trigger_reencryption){ 5212 sm_conn->sm_pairing_requested = true; 5213 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 5214 break; 5215 } 5216 /* fall through */ 5217 5218 case IRK_LOOKUP_FAILED: 5219 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5220 break; 5221 default: 5222 log_info("irk lookup pending"); 5223 sm_conn->sm_pairing_requested = true; 5224 break; 5225 } 5226 break; 5227 case SM_GENERAL_REENCRYPTION_FAILED: 5228 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5229 break; 5230 case SM_GENERAL_IDLE: 5231 sm_conn->sm_pairing_requested = true; 5232 break; 5233 default: 5234 break; 5235 } 5236 } 5237 sm_trigger_run(); 5238 } 5239 5240 // called by client app on authorization request 5241 void sm_authorization_decline(hci_con_handle_t con_handle){ 5242 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5243 if (!sm_conn) return; // wrong connection 5244 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 5245 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 5246 } 5247 5248 void sm_authorization_grant(hci_con_handle_t con_handle){ 5249 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5250 if (!sm_conn) return; // wrong connection 5251 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 5252 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 5253 } 5254 5255 // GAP Bonding API 5256 5257 void sm_bonding_decline(hci_con_handle_t con_handle){ 5258 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5259 if (!sm_conn) return; // wrong connection 5260 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 5261 log_info("decline, state %u", sm_conn->sm_engine_state); 5262 switch(sm_conn->sm_engine_state){ 5263 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5264 case SM_SC_W4_USER_RESPONSE: 5265 case SM_SC_W4_CONFIRMATION: 5266 case SM_SC_W4_PUBLIC_KEY_COMMAND: 5267 #endif 5268 case SM_PH1_W4_USER_RESPONSE: 5269 switch (setup->sm_stk_generation_method){ 5270 case PK_RESP_INPUT: 5271 case PK_INIT_INPUT: 5272 case PK_BOTH_INPUT: 5273 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 5274 break; 5275 case NUMERIC_COMPARISON: 5276 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 5277 break; 5278 case JUST_WORKS: 5279 case OOB: 5280 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 5281 break; 5282 default: 5283 btstack_assert(false); 5284 break; 5285 } 5286 break; 5287 default: 5288 break; 5289 } 5290 sm_trigger_run(); 5291 } 5292 5293 void sm_just_works_confirm(hci_con_handle_t con_handle){ 5294 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5295 if (!sm_conn) return; // wrong connection 5296 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 5297 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5298 if (setup->sm_use_secure_connections){ 5299 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 5300 } else { 5301 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); 5302 } 5303 } 5304 5305 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5306 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5307 sm_sc_prepare_dhkey_check(sm_conn); 5308 } 5309 #endif 5310 5311 sm_trigger_run(); 5312 } 5313 5314 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5315 // for now, it's the same 5316 sm_just_works_confirm(con_handle); 5317 } 5318 5319 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5320 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5321 if (!sm_conn) return; // wrong connection 5322 sm_reset_tk(); 5323 big_endian_store_32(setup->sm_tk, 12, passkey); 5324 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5325 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5326 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); 5327 } 5328 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5329 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5330 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5331 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5332 sm_sc_start_calculating_local_confirm(sm_conn); 5333 } 5334 #endif 5335 sm_trigger_run(); 5336 } 5337 5338 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5339 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5340 if (!sm_conn) return; // wrong connection 5341 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5342 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5343 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5344 switch (action){ 5345 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5346 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5347 flags |= (1u << action); 5348 break; 5349 case SM_KEYPRESS_PASSKEY_CLEARED: 5350 // clear counter, keypress & erased flags + set passkey cleared 5351 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5352 break; 5353 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5354 if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)) != 0u){ 5355 // erase actions queued 5356 num_actions--; 5357 if (num_actions == 0u){ 5358 // clear counter, keypress & erased flags 5359 flags &= 0x19u; 5360 } 5361 break; 5362 } 5363 num_actions++; 5364 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5365 break; 5366 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5367 if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)) != 0u){ 5368 // enter actions queued 5369 num_actions--; 5370 if (num_actions == 0u){ 5371 // clear counter, keypress & erased flags 5372 flags &= 0x19u; 5373 } 5374 break; 5375 } 5376 num_actions++; 5377 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5378 break; 5379 default: 5380 break; 5381 } 5382 setup->sm_keypress_notification = (num_actions << 5) | flags; 5383 sm_trigger_run(); 5384 } 5385 5386 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5387 static void sm_handle_random_result_oob(void * arg){ 5388 UNUSED(arg); 5389 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5390 sm_trigger_run(); 5391 } 5392 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5393 5394 static btstack_crypto_random_t sm_crypto_random_oob_request; 5395 5396 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5397 sm_sc_oob_callback = callback; 5398 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5399 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5400 return 0; 5401 } 5402 #endif 5403 5404 /** 5405 * @brief Get Identity Resolving state 5406 * @param con_handle 5407 * @return irk_lookup_state_t 5408 */ 5409 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5410 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5411 if (!sm_conn) return IRK_LOOKUP_IDLE; 5412 return sm_conn->sm_irk_lookup_state; 5413 } 5414 5415 /** 5416 * @brief Identify device in LE Device DB 5417 * @param handle 5418 * @return index from le_device_db or -1 if not found/identified 5419 */ 5420 int sm_le_device_index(hci_con_handle_t con_handle ){ 5421 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5422 if (!sm_conn) return -1; 5423 return sm_conn->sm_le_db_index; 5424 } 5425 5426 uint8_t sm_get_ltk(hci_con_handle_t con_handle, sm_key_t ltk){ 5427 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 5428 if (hci_connection == NULL){ 5429 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 5430 } 5431 if (hci_connection->link_key_type == 0){ 5432 return ERROR_CODE_PIN_OR_KEY_MISSING; 5433 } 5434 memcpy(ltk, hci_connection->link_key, 16); 5435 return ERROR_CODE_SUCCESS; 5436 } 5437 5438 static int gap_random_address_type_requires_updates(void){ 5439 switch (gap_random_adress_type){ 5440 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5441 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5442 return 0; 5443 default: 5444 return 1; 5445 } 5446 } 5447 5448 static uint8_t own_address_type(void){ 5449 switch (gap_random_adress_type){ 5450 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5451 return BD_ADDR_TYPE_LE_PUBLIC; 5452 default: 5453 return BD_ADDR_TYPE_LE_RANDOM; 5454 } 5455 } 5456 5457 // GAP LE API 5458 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5459 gap_random_address_update_stop(); 5460 gap_random_adress_type = random_address_type; 5461 hci_le_set_own_address_type(own_address_type()); 5462 if (!gap_random_address_type_requires_updates()) return; 5463 gap_random_address_update_start(); 5464 gap_random_address_trigger(); 5465 } 5466 5467 gap_random_address_type_t gap_random_address_get_mode(void){ 5468 return gap_random_adress_type; 5469 } 5470 5471 void gap_random_address_set_update_period(int period_ms){ 5472 gap_random_adress_update_period = period_ms; 5473 if (!gap_random_address_type_requires_updates()) return; 5474 gap_random_address_update_stop(); 5475 gap_random_address_update_start(); 5476 } 5477 5478 void gap_random_address_set(const bd_addr_t addr){ 5479 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5480 (void)memcpy(sm_random_address, addr, 6); 5481 // assert msb bits are set to '11' 5482 sm_random_address[0] |= 0xc0; 5483 hci_le_random_address_set(sm_random_address); 5484 } 5485 5486 #ifdef ENABLE_LE_PERIPHERAL 5487 /* 5488 * @brief Set Advertisement Paramters 5489 * @param adv_int_min 5490 * @param adv_int_max 5491 * @param adv_type 5492 * @param direct_address_type 5493 * @param direct_address 5494 * @param channel_map 5495 * @param filter_policy 5496 * 5497 * @note own_address_type is used from gap_random_address_set_mode 5498 */ 5499 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5500 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5501 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5502 direct_address_typ, direct_address, channel_map, filter_policy); 5503 } 5504 #endif 5505 5506 bool gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5507 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5508 // wrong connection 5509 if (!sm_conn) return false; 5510 // already encrypted 5511 if (sm_conn->sm_connection_encrypted) return false; 5512 // irk status? 5513 switch(sm_conn->sm_irk_lookup_state){ 5514 case IRK_LOOKUP_FAILED: 5515 // done, cannot setup encryption 5516 return false; 5517 case IRK_LOOKUP_SUCCEEDED: 5518 break; 5519 default: 5520 // IR Lookup pending 5521 return true; 5522 } 5523 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5524 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return false; 5525 if (sm_conn->sm_role != 0){ 5526 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5527 } else { 5528 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5529 } 5530 } 5531 5532 void sm_set_secure_connections_only_mode(bool enable){ 5533 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5534 sm_sc_only_mode = enable; 5535 #else 5536 // SC Only mode not possible without support for SC 5537 btstack_assert(enable == false); 5538 #endif 5539 } 5540 5541 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) 5542 void sm_test_enable_secure_connections_debug_keys(void) { 5543 log_info("Enable LE Secure Connection Debug Keys for testing"); 5544 sm_sc_debug_keys_enabled = true; 5545 // set debug key 5546 sm_ec_generate_new_key(); 5547 } 5548 #endif 5549 5550 const uint8_t * gap_get_persistent_irk(void){ 5551 return sm_persistent_irk; 5552 } 5553 5554 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5555 int index = sm_le_device_db_index_lookup(address_type, address); 5556 if (index >= 0){ 5557 sm_remove_le_device_db_entry(index); 5558 } 5559 } 5560