1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 } random_address_update_t; 111 112 typedef enum { 113 CMAC_IDLE, 114 CMAC_CALC_SUBKEYS, 115 CMAC_W4_SUBKEYS, 116 CMAC_CALC_MI, 117 CMAC_W4_MI, 118 CMAC_CALC_MLAST, 119 CMAC_W4_MLAST 120 } cmac_state_t; 121 122 typedef enum { 123 JUST_WORKS, 124 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 125 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 126 PK_BOTH_INPUT, // Only input on both, both input PK 127 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 128 OOB // OOB available on one (SC) or both sides (legacy) 129 } stk_generation_method_t; 130 131 typedef enum { 132 SM_USER_RESPONSE_IDLE, 133 SM_USER_RESPONSE_PENDING, 134 SM_USER_RESPONSE_CONFIRM, 135 SM_USER_RESPONSE_PASSKEY, 136 SM_USER_RESPONSE_DECLINE 137 } sm_user_response_t; 138 139 typedef enum { 140 SM_AES128_IDLE, 141 SM_AES128_ACTIVE 142 } sm_aes128_state_t; 143 144 typedef enum { 145 ADDRESS_RESOLUTION_IDLE, 146 ADDRESS_RESOLUTION_GENERAL, 147 ADDRESS_RESOLUTION_FOR_CONNECTION, 148 } address_resolution_mode_t; 149 150 typedef enum { 151 ADDRESS_RESOLUTION_SUCCEEDED, 152 ADDRESS_RESOLUTION_FAILED, 153 } address_resolution_event_t; 154 155 typedef enum { 156 EC_KEY_GENERATION_IDLE, 157 EC_KEY_GENERATION_ACTIVE, 158 EC_KEY_GENERATION_DONE, 159 } ec_key_generation_state_t; 160 161 typedef enum { 162 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 163 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 165 } sm_state_var_t; 166 167 typedef enum { 168 SM_SC_OOB_IDLE, 169 SM_SC_OOB_W4_RANDOM, 170 SM_SC_OOB_W2_CALC_CONFIRM, 171 SM_SC_OOB_W4_CONFIRM, 172 } sm_sc_oob_state_t; 173 174 typedef uint8_t sm_key24_t[3]; 175 typedef uint8_t sm_key56_t[7]; 176 typedef uint8_t sm_key256_t[32]; 177 178 // 179 // GLOBAL DATA 180 // 181 182 static bool sm_initialized; 183 184 static bool test_use_fixed_local_csrk; 185 static bool test_use_fixed_local_irk; 186 187 #ifdef ENABLE_TESTING_SUPPORT 188 static uint8_t test_pairing_failure; 189 #endif 190 191 // configuration 192 static uint8_t sm_accepted_stk_generation_methods; 193 static uint8_t sm_max_encryption_key_size; 194 static uint8_t sm_min_encryption_key_size; 195 static uint8_t sm_auth_req = 0; 196 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static bool sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_PERIPHERAL 201 static uint8_t sm_slave_request_security; 202 #endif 203 204 #ifdef ENABLE_LE_SECURE_CONNECTIONS 205 static bool sm_sc_only_mode; 206 static uint8_t sm_sc_oob_random[16]; 207 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 208 static sm_sc_oob_state_t sm_sc_oob_state; 209 #endif 210 211 212 static bool sm_persistent_keys_random_active; 213 static const btstack_tlv_t * sm_tlv_impl; 214 static void * sm_tlv_context; 215 216 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 217 static sm_key_t sm_persistent_er; 218 static sm_key_t sm_persistent_ir; 219 220 // derived from sm_persistent_ir 221 static sm_key_t sm_persistent_dhk; 222 static sm_key_t sm_persistent_irk; 223 static derived_key_generation_t dkg_state; 224 225 // derived from sm_persistent_er 226 // .. 227 228 // random address update 229 static random_address_update_t rau_state; 230 static bd_addr_t sm_random_address; 231 232 #ifdef USE_CMAC_ENGINE 233 // CMAC Calculation: General 234 static btstack_crypto_aes128_cmac_t sm_cmac_request; 235 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 236 static uint8_t sm_cmac_active; 237 static uint8_t sm_cmac_hash[16]; 238 #endif 239 240 // CMAC for ATT Signed Writes 241 #ifdef ENABLE_LE_SIGNED_WRITE 242 static uint16_t sm_cmac_signed_write_message_len; 243 static uint8_t sm_cmac_signed_write_header[3]; 244 static const uint8_t * sm_cmac_signed_write_message; 245 static uint8_t sm_cmac_signed_write_sign_counter[4]; 246 #endif 247 248 // CMAC for Secure Connection functions 249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 250 static sm_connection_t * sm_cmac_connection; 251 static uint8_t sm_cmac_sc_buffer[80]; 252 #endif 253 254 // resolvable private address lookup / CSRK calculation 255 static int sm_address_resolution_test; 256 static int sm_address_resolution_ah_calculation_active; 257 static uint8_t sm_address_resolution_addr_type; 258 static bd_addr_t sm_address_resolution_address; 259 static void * sm_address_resolution_context; 260 static address_resolution_mode_t sm_address_resolution_mode; 261 static btstack_linked_list_t sm_address_resolution_general_queue; 262 263 // aes128 crypto engine. 264 static sm_aes128_state_t sm_aes128_state; 265 266 // crypto 267 static btstack_crypto_random_t sm_crypto_random_request; 268 static btstack_crypto_aes128_t sm_crypto_aes128_request; 269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 270 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 271 #endif 272 273 // temp storage for random data 274 static uint8_t sm_random_data[8]; 275 static uint8_t sm_aes128_key[16]; 276 static uint8_t sm_aes128_plaintext[16]; 277 static uint8_t sm_aes128_ciphertext[16]; 278 279 // to receive hci events 280 static btstack_packet_callback_registration_t hci_event_callback_registration; 281 282 /* to dispatch sm event */ 283 static btstack_linked_list_t sm_event_handlers; 284 285 /* to schedule calls to sm_run */ 286 static btstack_timer_source_t sm_run_timer; 287 288 // LE Secure Connections 289 #ifdef ENABLE_LE_SECURE_CONNECTIONS 290 static ec_key_generation_state_t ec_key_generation_state; 291 static uint8_t ec_q[64]; 292 #endif 293 294 // 295 // Volume 3, Part H, Chapter 24 296 // "Security shall be initiated by the Security Manager in the device in the master role. 297 // The device in the slave role shall be the responding device." 298 // -> master := initiator, slave := responder 299 // 300 301 // data needed for security setup 302 typedef struct sm_setup_context { 303 304 btstack_timer_source_t sm_timeout; 305 306 // user response, (Phase 1 and/or 2) 307 uint8_t sm_user_response; 308 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 309 310 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 311 uint8_t sm_key_distribution_send_set; 312 uint8_t sm_key_distribution_sent_set; 313 uint8_t sm_key_distribution_expected_set; 314 uint8_t sm_key_distribution_received_set; 315 316 // Phase 2 (Pairing over SMP) 317 stk_generation_method_t sm_stk_generation_method; 318 sm_key_t sm_tk; 319 uint8_t sm_have_oob_data; 320 uint8_t sm_use_secure_connections; 321 322 sm_key_t sm_c1_t3_value; // c1 calculation 323 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 324 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 325 sm_key_t sm_local_random; 326 sm_key_t sm_local_confirm; 327 sm_key_t sm_peer_random; 328 sm_key_t sm_peer_confirm; 329 uint8_t sm_m_addr_type; // address and type can be removed 330 uint8_t sm_s_addr_type; // '' 331 bd_addr_t sm_m_address; // '' 332 bd_addr_t sm_s_address; // '' 333 sm_key_t sm_ltk; 334 335 uint8_t sm_state_vars; 336 #ifdef ENABLE_LE_SECURE_CONNECTIONS 337 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 338 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 339 sm_key_t sm_local_nonce; // might be combined with sm_local_random 340 uint8_t sm_dhkey[32]; 341 sm_key_t sm_peer_dhkey_check; 342 sm_key_t sm_local_dhkey_check; 343 sm_key_t sm_ra; 344 sm_key_t sm_rb; 345 sm_key_t sm_t; // used for f5 and h6 346 sm_key_t sm_mackey; 347 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 348 #endif 349 350 // Phase 3 351 352 // key distribution, we generate 353 uint16_t sm_local_y; 354 uint16_t sm_local_div; 355 uint16_t sm_local_ediv; 356 uint8_t sm_local_rand[8]; 357 sm_key_t sm_local_ltk; 358 sm_key_t sm_local_csrk; 359 sm_key_t sm_local_irk; 360 // sm_local_address/addr_type not needed 361 362 // key distribution, received from peer 363 uint16_t sm_peer_y; 364 uint16_t sm_peer_div; 365 uint16_t sm_peer_ediv; 366 uint8_t sm_peer_rand[8]; 367 sm_key_t sm_peer_ltk; 368 sm_key_t sm_peer_irk; 369 sm_key_t sm_peer_csrk; 370 uint8_t sm_peer_addr_type; 371 bd_addr_t sm_peer_address; 372 #ifdef ENABLE_LE_SIGNED_WRITE 373 int sm_le_device_index; 374 #endif 375 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 376 link_key_t sm_link_key; 377 link_key_type_t sm_link_key_type; 378 #endif 379 } sm_setup_context_t; 380 381 // 382 static sm_setup_context_t the_setup; 383 static sm_setup_context_t * setup = &the_setup; 384 385 // active connection - the one for which the_setup is used for 386 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 387 388 // @return 1 if oob data is available 389 // stores oob data in provided 16 byte buffer if not null 390 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 391 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 392 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 393 394 static void sm_run(void); 395 static void sm_state_reset(void); 396 static void sm_done_for_handle(hci_con_handle_t con_handle); 397 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 398 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 399 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 400 #endif 401 static inline int sm_calc_actual_encryption_key_size(int other); 402 static int sm_validate_stk_generation_method(void); 403 static void sm_handle_encryption_result_address_resolution(void *arg); 404 static void sm_handle_encryption_result_dkg_dhk(void *arg); 405 static void sm_handle_encryption_result_dkg_irk(void *arg); 406 static void sm_handle_encryption_result_enc_a(void *arg); 407 static void sm_handle_encryption_result_enc_b(void *arg); 408 static void sm_handle_encryption_result_enc_c(void *arg); 409 static void sm_handle_encryption_result_enc_csrk(void *arg); 410 static void sm_handle_encryption_result_enc_d(void * arg); 411 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 412 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 413 #ifdef ENABLE_LE_PERIPHERAL 414 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 415 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 416 #endif 417 static void sm_handle_encryption_result_enc_stk(void *arg); 418 static void sm_handle_encryption_result_rau(void *arg); 419 static void sm_handle_random_result_ph2_tk(void * arg); 420 static void sm_handle_random_result_rau(void * arg); 421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 422 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)); 423 static void sm_ec_generate_new_key(void); 424 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 425 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 426 static int sm_passkey_entry(stk_generation_method_t method); 427 #endif 428 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 429 430 static void log_info_hex16(const char * name, uint16_t value){ 431 log_info("%-6s 0x%04x", name, value); 432 } 433 434 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 435 // return packet[0]; 436 // } 437 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 438 return packet[1]; 439 } 440 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 441 return packet[2]; 442 } 443 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 444 return packet[3]; 445 } 446 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 447 return packet[4]; 448 } 449 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 450 return packet[5]; 451 } 452 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 453 return packet[6]; 454 } 455 456 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 457 packet[0] = code; 458 } 459 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 460 packet[1] = io_capability; 461 } 462 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 463 packet[2] = oob_data_flag; 464 } 465 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 466 packet[3] = auth_req; 467 } 468 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 469 packet[4] = max_encryption_key_size; 470 } 471 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 472 packet[5] = initiator_key_distribution; 473 } 474 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 475 packet[6] = responder_key_distribution; 476 } 477 478 // @return 1 if all bytes are 0 479 static bool sm_is_null(uint8_t * data, int size){ 480 int i; 481 for (i=0; i < size ; i++){ 482 if (data[i] != 0) { 483 return false; 484 } 485 } 486 return true; 487 } 488 489 static bool sm_is_null_random(uint8_t random[8]){ 490 return sm_is_null(random, 8); 491 } 492 493 static bool sm_is_null_key(uint8_t * key){ 494 return sm_is_null(key, 16); 495 } 496 497 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 498 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 499 UNUSED(ts); 500 sm_run(); 501 } 502 static void sm_trigger_run(void){ 503 if (!sm_initialized) return; 504 (void)btstack_run_loop_remove_timer(&sm_run_timer); 505 btstack_run_loop_set_timer(&sm_run_timer, 0); 506 btstack_run_loop_add_timer(&sm_run_timer); 507 } 508 509 // Key utils 510 static void sm_reset_tk(void){ 511 int i; 512 for (i=0;i<16;i++){ 513 setup->sm_tk[i] = 0; 514 } 515 } 516 517 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 518 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 519 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 520 int i; 521 for (i = max_encryption_size ; i < 16 ; i++){ 522 key[15-i] = 0; 523 } 524 } 525 526 // ER / IR checks 527 static void sm_er_ir_set_default(void){ 528 int i; 529 for (i=0;i<16;i++){ 530 sm_persistent_er[i] = 0x30 + i; 531 sm_persistent_ir[i] = 0x90 + i; 532 } 533 } 534 535 static int sm_er_is_default(void){ 536 int i; 537 for (i=0;i<16;i++){ 538 if (sm_persistent_er[i] != (0x30+i)) return 0; 539 } 540 return 1; 541 } 542 543 static int sm_ir_is_default(void){ 544 int i; 545 for (i=0;i<16;i++){ 546 if (sm_persistent_ir[i] != (0x90+i)) return 0; 547 } 548 return 1; 549 } 550 551 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 552 UNUSED(channel); 553 554 // log event 555 hci_dump_packet(packet_type, 1, packet, size); 556 // dispatch to all event handlers 557 btstack_linked_list_iterator_t it; 558 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 559 while (btstack_linked_list_iterator_has_next(&it)){ 560 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 561 entry->callback(packet_type, 0, packet, size); 562 } 563 } 564 565 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){ 566 event[0] = type; 567 event[1] = event_size - 2; 568 little_endian_store_16(event, 2, con_handle); 569 event[4] = addr_type; 570 reverse_bd_addr(address, &event[5]); 571 } 572 573 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 574 uint8_t event[11]; 575 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 576 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 577 } 578 579 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){ 580 // fetch addr and addr type from db, only called for valid entries 581 bd_addr_t identity_address; 582 int identity_address_type; 583 le_device_db_info(index, &identity_address_type, identity_address, NULL); 584 585 uint8_t event[20]; 586 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 587 event[11] = identity_address_type; 588 reverse_bd_addr(identity_address, &event[12]); 589 little_endian_store_16(event, 18, index); 590 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 591 } 592 593 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){ 594 uint8_t event[12]; 595 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 596 event[11] = status; 597 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 598 } 599 600 601 static void sm_reencryption_started(sm_connection_t * sm_conn){ 602 603 if (sm_conn->sm_reencryption_active) return; 604 605 sm_conn->sm_reencryption_active = true; 606 607 int identity_addr_type; 608 bd_addr_t identity_addr; 609 if (sm_conn->sm_le_db_index >= 0){ 610 // fetch addr and addr type from db, only called for valid entries 611 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 612 } else { 613 // for legacy pairing with LTK re-construction, use current peer addr 614 identity_addr_type = sm_conn->sm_peer_addr_type; 615 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 616 } 617 618 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 619 } 620 621 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 622 623 if (!sm_conn->sm_reencryption_active) return; 624 625 sm_conn->sm_reencryption_active = false; 626 627 int identity_addr_type; 628 bd_addr_t identity_addr; 629 if (sm_conn->sm_le_db_index >= 0){ 630 // fetch addr and addr type from db, only called for valid entries 631 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 632 } else { 633 // for legacy pairing with LTK re-construction, use current peer addr 634 identity_addr_type = sm_conn->sm_peer_addr_type; 635 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 636 } 637 638 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 639 } 640 641 static void sm_pairing_started(sm_connection_t * sm_conn){ 642 643 if (sm_conn->sm_pairing_active) return; 644 645 sm_conn->sm_pairing_active = true; 646 647 uint8_t event[11]; 648 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 649 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 650 } 651 652 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 653 654 if (!sm_conn->sm_pairing_active) return; 655 656 sm_conn->sm_pairing_active = false; 657 658 uint8_t event[13]; 659 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 660 event[11] = status; 661 event[12] = reason; 662 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 663 } 664 665 // SMP Timeout implementation 666 667 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 668 // the Security Manager Timer shall be reset and started. 669 // 670 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 671 // 672 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 673 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 674 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 675 // established. 676 677 static void sm_timeout_handler(btstack_timer_source_t * timer){ 678 log_info("SM timeout"); 679 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 680 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 681 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 682 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 683 sm_done_for_handle(sm_conn->sm_handle); 684 685 // trigger handling of next ready connection 686 sm_run(); 687 } 688 static void sm_timeout_start(sm_connection_t * sm_conn){ 689 btstack_run_loop_remove_timer(&setup->sm_timeout); 690 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 691 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 692 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 693 btstack_run_loop_add_timer(&setup->sm_timeout); 694 } 695 static void sm_timeout_stop(void){ 696 btstack_run_loop_remove_timer(&setup->sm_timeout); 697 } 698 static void sm_timeout_reset(sm_connection_t * sm_conn){ 699 sm_timeout_stop(); 700 sm_timeout_start(sm_conn); 701 } 702 703 // end of sm timeout 704 705 // GAP Random Address updates 706 static gap_random_address_type_t gap_random_adress_type; 707 static btstack_timer_source_t gap_random_address_update_timer; 708 static uint32_t gap_random_adress_update_period; 709 710 static void gap_random_address_trigger(void){ 711 log_info("gap_random_address_trigger, state %u", rau_state); 712 if (rau_state != RAU_IDLE) return; 713 rau_state = RAU_GET_RANDOM; 714 sm_trigger_run(); 715 } 716 717 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 718 UNUSED(timer); 719 720 log_info("GAP Random Address Update due"); 721 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 722 btstack_run_loop_add_timer(&gap_random_address_update_timer); 723 gap_random_address_trigger(); 724 } 725 726 static void gap_random_address_update_start(void){ 727 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 728 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 729 btstack_run_loop_add_timer(&gap_random_address_update_timer); 730 } 731 732 static void gap_random_address_update_stop(void){ 733 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 734 } 735 736 // ah(k,r) helper 737 // r = padding || r 738 // r - 24 bit value 739 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 740 // r'= padding || r 741 memset(r_prime, 0, 16); 742 (void)memcpy(&r_prime[13], r, 3); 743 } 744 745 // d1 helper 746 // d' = padding || r || d 747 // d,r - 16 bit values 748 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 749 // d'= padding || r || d 750 memset(d1_prime, 0, 16); 751 big_endian_store_16(d1_prime, 12, r); 752 big_endian_store_16(d1_prime, 14, d); 753 } 754 755 // calculate arguments for first AES128 operation in C1 function 756 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){ 757 758 // p1 = pres || preq || rat’ || iat’ 759 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 760 // cant octet of pres becomes the most significant octet of p1. 761 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 762 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 763 // p1 is 0x05000800000302070710000001010001." 764 765 sm_key_t p1; 766 reverse_56(pres, &p1[0]); 767 reverse_56(preq, &p1[7]); 768 p1[14] = rat; 769 p1[15] = iat; 770 log_info_key("p1", p1); 771 log_info_key("r", r); 772 773 // t1 = r xor p1 774 int i; 775 for (i=0;i<16;i++){ 776 t1[i] = r[i] ^ p1[i]; 777 } 778 log_info_key("t1", t1); 779 } 780 781 // calculate arguments for second AES128 operation in C1 function 782 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 783 // p2 = padding || ia || ra 784 // "The least significant octet of ra becomes the least significant octet of p2 and 785 // the most significant octet of padding becomes the most significant octet of p2. 786 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 787 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 788 789 sm_key_t p2; 790 memset(p2, 0, 16); 791 (void)memcpy(&p2[4], ia, 6); 792 (void)memcpy(&p2[10], ra, 6); 793 log_info_key("p2", p2); 794 795 // c1 = e(k, t2_xor_p2) 796 int i; 797 for (i=0;i<16;i++){ 798 t3[i] = t2[i] ^ p2[i]; 799 } 800 log_info_key("t3", t3); 801 } 802 803 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 804 log_info_key("r1", r1); 805 log_info_key("r2", r2); 806 (void)memcpy(&r_prime[8], &r2[8], 8); 807 (void)memcpy(&r_prime[0], &r1[8], 8); 808 } 809 810 811 // decide on stk generation based on 812 // - pairing request 813 // - io capabilities 814 // - OOB data availability 815 static void sm_setup_tk(void){ 816 817 // horizontal: initiator capabilities 818 // vertial: responder capabilities 819 static const stk_generation_method_t stk_generation_method [5] [5] = { 820 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 821 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 822 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 823 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 824 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 825 }; 826 827 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 828 #ifdef ENABLE_LE_SECURE_CONNECTIONS 829 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 830 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 831 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 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, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 835 }; 836 #endif 837 838 // default: just works 839 setup->sm_stk_generation_method = JUST_WORKS; 840 841 #ifdef ENABLE_LE_SECURE_CONNECTIONS 842 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 843 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 844 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 845 #else 846 setup->sm_use_secure_connections = 0; 847 #endif 848 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 849 850 851 // decide if OOB will be used based on SC vs. Legacy and oob flags 852 bool use_oob; 853 if (setup->sm_use_secure_connections){ 854 // In LE Secure Connections pairing, the out of band method is used if at least 855 // one device has the peer device's out of band authentication data available. 856 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; 857 } else { 858 // In LE legacy pairing, the out of band method is used if both the devices have 859 // the other device's out of band authentication data available. 860 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; 861 } 862 if (use_oob){ 863 log_info("SM: have OOB data"); 864 log_info_key("OOB", setup->sm_tk); 865 setup->sm_stk_generation_method = OOB; 866 return; 867 } 868 869 // If both devices have not set the MITM option in the Authentication Requirements 870 // Flags, then the IO capabilities shall be ignored and the Just Works association 871 // model shall be used. 872 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 873 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 874 log_info("SM: MITM not required by both -> JUST WORKS"); 875 return; 876 } 877 878 // Reset TK as it has been setup in sm_init_setup 879 sm_reset_tk(); 880 881 // Also use just works if unknown io capabilites 882 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)){ 883 return; 884 } 885 886 // Otherwise the IO capabilities of the devices shall be used to determine the 887 // pairing method as defined in Table 2.4. 888 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 889 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 890 891 #ifdef ENABLE_LE_SECURE_CONNECTIONS 892 // table not define by default 893 if (setup->sm_use_secure_connections){ 894 generation_method = stk_generation_method_with_secure_connection; 895 } 896 #endif 897 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)]; 898 899 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 900 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); 901 } 902 903 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 904 int flags = 0; 905 if (key_set & SM_KEYDIST_ENC_KEY){ 906 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 907 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 908 } 909 if (key_set & SM_KEYDIST_ID_KEY){ 910 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 911 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 912 } 913 if (key_set & SM_KEYDIST_SIGN){ 914 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 915 } 916 return flags; 917 } 918 919 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 920 setup->sm_key_distribution_received_set = 0; 921 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 922 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 923 setup->sm_key_distribution_sent_set = 0; 924 #ifdef ENABLE_LE_SIGNED_WRITE 925 setup->sm_le_device_index = -1; 926 #endif 927 } 928 929 // CSRK Key Lookup 930 931 932 static int sm_address_resolution_idle(void){ 933 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 934 } 935 936 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){ 937 (void)memcpy(sm_address_resolution_address, addr, 6); 938 sm_address_resolution_addr_type = addr_type; 939 sm_address_resolution_test = 0; 940 sm_address_resolution_mode = mode; 941 sm_address_resolution_context = context; 942 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 943 } 944 945 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 946 // check if already in list 947 btstack_linked_list_iterator_t it; 948 sm_lookup_entry_t * entry; 949 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 950 while(btstack_linked_list_iterator_has_next(&it)){ 951 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 952 if (entry->address_type != address_type) continue; 953 if (memcmp(entry->address, address, 6)) continue; 954 // already in list 955 return BTSTACK_BUSY; 956 } 957 entry = btstack_memory_sm_lookup_entry_get(); 958 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 959 entry->address_type = (bd_addr_type_t) address_type; 960 (void)memcpy(entry->address, address, 6); 961 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 962 sm_trigger_run(); 963 return 0; 964 } 965 966 // CMAC calculation using AES Engineq 967 #ifdef USE_CMAC_ENGINE 968 969 static void sm_cmac_done_trampoline(void * arg){ 970 UNUSED(arg); 971 sm_cmac_active = 0; 972 (*sm_cmac_done_callback)(sm_cmac_hash); 973 sm_trigger_run(); 974 } 975 976 int sm_cmac_ready(void){ 977 return sm_cmac_active == 0u; 978 } 979 #endif 980 981 #ifdef ENABLE_LE_SECURE_CONNECTIONS 982 // generic cmac calculation 983 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)){ 984 sm_cmac_active = 1; 985 sm_cmac_done_callback = done_callback; 986 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 987 } 988 #endif 989 990 // cmac for ATT Message signing 991 #ifdef ENABLE_LE_SIGNED_WRITE 992 993 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)){ 994 sm_cmac_active = 1; 995 sm_cmac_done_callback = done_callback; 996 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 997 } 998 999 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1000 if (offset >= sm_cmac_signed_write_message_len) { 1001 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1002 return 0; 1003 } 1004 1005 offset = sm_cmac_signed_write_message_len - 1 - offset; 1006 1007 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1008 if (offset < 3){ 1009 return sm_cmac_signed_write_header[offset]; 1010 } 1011 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1012 if (offset < actual_message_len_incl_header){ 1013 return sm_cmac_signed_write_message[offset - 3]; 1014 } 1015 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1016 } 1017 1018 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)){ 1019 // ATT Message Signing 1020 sm_cmac_signed_write_header[0] = opcode; 1021 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1022 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1023 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1024 sm_cmac_signed_write_message = message; 1025 sm_cmac_signed_write_message_len = total_message_len; 1026 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1027 } 1028 #endif 1029 1030 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1031 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1032 uint8_t event[12]; 1033 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1034 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1035 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1036 } 1037 1038 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn){ 1039 uint8_t event[16]; 1040 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1041 sm_setup_event_base(event, sizeof(event), SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, 1042 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1043 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1044 little_endian_store_32(event, 12, passkey); 1045 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1046 } 1047 1048 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1049 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1050 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1051 sm_conn->sm_pairing_active = true; 1052 switch (setup->sm_stk_generation_method){ 1053 case PK_RESP_INPUT: 1054 if (IS_RESPONDER(sm_conn->sm_role)){ 1055 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1056 } else { 1057 sm_trigger_user_response_passkey(sm_conn); 1058 } 1059 break; 1060 case PK_INIT_INPUT: 1061 if (IS_RESPONDER(sm_conn->sm_role)){ 1062 sm_trigger_user_response_passkey(sm_conn); 1063 } else { 1064 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1065 } 1066 break; 1067 case PK_BOTH_INPUT: 1068 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1069 break; 1070 case NUMERIC_COMPARISON: 1071 sm_trigger_user_response_basic(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1072 break; 1073 case JUST_WORKS: 1074 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1075 break; 1076 case OOB: 1077 // client already provided OOB data, let's skip notification. 1078 break; 1079 default: 1080 btstack_assert(false); 1081 break; 1082 } 1083 } 1084 1085 static bool sm_key_distribution_all_received(void) { 1086 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); 1087 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1088 } 1089 1090 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1091 if (sm_active_connection_handle == con_handle){ 1092 sm_timeout_stop(); 1093 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1094 log_info("sm: connection 0x%x released setup context", con_handle); 1095 1096 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1097 // generate new ec key after each pairing (that used it) 1098 if (setup->sm_use_secure_connections){ 1099 sm_ec_generate_new_key(); 1100 } 1101 #endif 1102 } 1103 } 1104 1105 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1106 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1107 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1108 sm_done_for_handle(connection->sm_handle); 1109 } 1110 1111 static int sm_key_distribution_flags_for_auth_req(void){ 1112 1113 int flags = SM_KEYDIST_ID_KEY; 1114 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1115 // encryption and signing information only if bonding requested 1116 flags |= SM_KEYDIST_ENC_KEY; 1117 #ifdef ENABLE_LE_SIGNED_WRITE 1118 flags |= SM_KEYDIST_SIGN; 1119 #endif 1120 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1121 // LinkKey for CTKD requires SC 1122 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1123 flags |= SM_KEYDIST_LINK_KEY; 1124 } 1125 #endif 1126 } 1127 return flags; 1128 } 1129 1130 static void sm_reset_setup(void){ 1131 // fill in sm setup 1132 setup->sm_state_vars = 0; 1133 setup->sm_keypress_notification = 0; 1134 setup->sm_have_oob_data = 0; 1135 sm_reset_tk(); 1136 } 1137 1138 static void sm_init_setup(sm_connection_t * sm_conn){ 1139 // fill in sm setup 1140 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1141 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1142 1143 // query client for Legacy Pairing OOB data 1144 if (sm_get_oob_data != NULL) { 1145 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1146 } 1147 1148 // if available and SC supported, also ask for SC OOB Data 1149 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1150 memset(setup->sm_ra, 0, 16); 1151 memset(setup->sm_rb, 0, 16); 1152 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1153 if (sm_get_sc_oob_data != NULL){ 1154 if (IS_RESPONDER(sm_conn->sm_role)){ 1155 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1156 sm_conn->sm_peer_addr_type, 1157 sm_conn->sm_peer_address, 1158 setup->sm_peer_confirm, 1159 setup->sm_ra); 1160 } else { 1161 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1162 sm_conn->sm_peer_addr_type, 1163 sm_conn->sm_peer_address, 1164 setup->sm_peer_confirm, 1165 setup->sm_rb); 1166 } 1167 } else { 1168 setup->sm_have_oob_data = 0; 1169 } 1170 } 1171 #endif 1172 1173 sm_pairing_packet_t * local_packet; 1174 if (IS_RESPONDER(sm_conn->sm_role)){ 1175 // slave 1176 local_packet = &setup->sm_s_pres; 1177 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1178 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1179 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1180 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1181 } else { 1182 // master 1183 local_packet = &setup->sm_m_preq; 1184 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1185 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1186 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1187 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1188 1189 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1190 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1191 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1192 } 1193 1194 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1195 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1196 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1197 // enable SC for SC only mode 1198 if (sm_sc_only_mode){ 1199 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1200 max_encryption_key_size = 16; 1201 } 1202 #endif 1203 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1204 // set CT2 if SC + Bonding + CTKD 1205 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1206 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1207 auth_req |= SM_AUTHREQ_CT2; 1208 } 1209 #endif 1210 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1211 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1212 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1213 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1214 } 1215 1216 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1217 1218 sm_pairing_packet_t * remote_packet; 1219 uint8_t keys_to_send; 1220 uint8_t keys_to_receive; 1221 if (IS_RESPONDER(sm_conn->sm_role)){ 1222 // slave / responder 1223 remote_packet = &setup->sm_m_preq; 1224 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1225 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1226 } else { 1227 // master / initiator 1228 remote_packet = &setup->sm_s_pres; 1229 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1230 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1231 } 1232 1233 // check key size 1234 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1235 // SC Only mandates 128 bit key size 1236 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1237 return SM_REASON_ENCRYPTION_KEY_SIZE; 1238 } 1239 #endif 1240 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1241 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1242 1243 // decide on STK generation method / SC 1244 sm_setup_tk(); 1245 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1246 1247 // check if STK generation method is acceptable by client 1248 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1249 1250 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1251 // Check LE SC Only mode 1252 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1253 log_info("SC Only mode active but SC not possible"); 1254 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1255 } 1256 1257 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1258 if (setup->sm_use_secure_connections){ 1259 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1260 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1261 } 1262 #endif 1263 1264 // identical to responder 1265 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1266 1267 // JUST WORKS doens't provide authentication 1268 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1269 1270 return 0; 1271 } 1272 1273 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1274 1275 // cache and reset context 1276 int matched_device_id = sm_address_resolution_test; 1277 address_resolution_mode_t mode = sm_address_resolution_mode; 1278 void * context = sm_address_resolution_context; 1279 1280 // reset context 1281 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1282 sm_address_resolution_context = NULL; 1283 sm_address_resolution_test = -1; 1284 hci_con_handle_t con_handle = 0; 1285 1286 sm_connection_t * sm_connection; 1287 sm_key_t ltk; 1288 bool have_ltk; 1289 #ifdef ENABLE_LE_CENTRAL 1290 bool trigger_pairing; 1291 #endif 1292 switch (mode){ 1293 case ADDRESS_RESOLUTION_GENERAL: 1294 break; 1295 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1296 sm_connection = (sm_connection_t *) context; 1297 con_handle = sm_connection->sm_handle; 1298 1299 // have ltk -> start encryption / send security request 1300 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1301 // "When a bond has been created between two devices, any reconnection should result in the local device 1302 // enabling or requesting encryption with the remote device before initiating any service request." 1303 1304 switch (event){ 1305 case ADDRESS_RESOLUTION_SUCCEEDED: 1306 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1307 sm_connection->sm_le_db_index = matched_device_id; 1308 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1309 1310 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1311 have_ltk = !sm_is_null_key(ltk); 1312 1313 if (sm_connection->sm_role) { 1314 #ifdef ENABLE_LE_PERIPHERAL 1315 // IRK required before, continue 1316 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1317 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1318 break; 1319 } 1320 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1321 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1322 break; 1323 } 1324 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1325 sm_connection->sm_pairing_requested = 0; 1326 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1327 // trigger security request for Proactive Authentication if LTK available 1328 trigger_security_request = trigger_security_request || have_ltk; 1329 #endif 1330 1331 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1332 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1333 1334 if (trigger_security_request){ 1335 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1336 if (have_ltk){ 1337 sm_reencryption_started(sm_connection); 1338 } else { 1339 sm_pairing_started(sm_connection); 1340 } 1341 sm_trigger_run(); 1342 } 1343 #endif 1344 } else { 1345 1346 #ifdef ENABLE_LE_CENTRAL 1347 // check if pairing already requested and reset requests 1348 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1349 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1350 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1351 sm_connection->sm_security_request_received = 0; 1352 sm_connection->sm_pairing_requested = 0; 1353 bool trigger_reencryption = false; 1354 1355 if (have_ltk){ 1356 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1357 trigger_reencryption = true; 1358 #else 1359 if (trigger_pairing){ 1360 trigger_reencryption = true; 1361 } else { 1362 log_info("central: defer enabling encryption for bonded device"); 1363 } 1364 #endif 1365 } 1366 1367 if (trigger_reencryption){ 1368 log_info("central: enable encryption for bonded device"); 1369 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1370 break; 1371 } 1372 1373 // pairing_request -> send pairing request 1374 if (trigger_pairing){ 1375 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1376 break; 1377 } 1378 #endif 1379 } 1380 break; 1381 case ADDRESS_RESOLUTION_FAILED: 1382 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1383 if (sm_connection->sm_role) { 1384 #ifdef ENABLE_LE_PERIPHERAL 1385 // LTK request received before, IRK required -> negative LTK reply 1386 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1387 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1388 } 1389 // send security request if requested 1390 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1391 sm_connection->sm_pairing_requested = 0; 1392 if (trigger_security_request){ 1393 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1394 sm_pairing_started(sm_connection); 1395 } 1396 break; 1397 #endif 1398 } 1399 #ifdef ENABLE_LE_CENTRAL 1400 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1401 sm_connection->sm_security_request_received = 0; 1402 sm_connection->sm_pairing_requested = 0; 1403 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1404 #endif 1405 break; 1406 1407 default: 1408 btstack_assert(false); 1409 break; 1410 } 1411 break; 1412 default: 1413 break; 1414 } 1415 1416 switch (event){ 1417 case ADDRESS_RESOLUTION_SUCCEEDED: 1418 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1419 break; 1420 case ADDRESS_RESOLUTION_FAILED: 1421 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1422 break; 1423 default: 1424 btstack_assert(false); 1425 break; 1426 } 1427 } 1428 1429 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1430 int le_db_index = -1; 1431 1432 // lookup device based on IRK 1433 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1434 int i; 1435 for (i=0; i < le_device_db_max_count(); i++){ 1436 sm_key_t irk; 1437 bd_addr_t address; 1438 int address_type = BD_ADDR_TYPE_UNKNOWN; 1439 le_device_db_info(i, &address_type, address, irk); 1440 // skip unused entries 1441 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1442 // compare Identity Address 1443 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1444 // compare Identity Resolving Key 1445 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1446 1447 log_info("sm: device found for IRK, updating"); 1448 le_db_index = i; 1449 break; 1450 } 1451 } else { 1452 // assert IRK is set to zero 1453 memset(setup->sm_peer_irk, 0, 16); 1454 } 1455 1456 // if not found, lookup via public address if possible 1457 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1458 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1459 int i; 1460 for (i=0; i < le_device_db_max_count(); i++){ 1461 bd_addr_t address; 1462 int address_type = BD_ADDR_TYPE_UNKNOWN; 1463 le_device_db_info(i, &address_type, address, NULL); 1464 // skip unused entries 1465 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1466 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1467 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1468 log_info("sm: device found for public address, updating"); 1469 le_db_index = i; 1470 break; 1471 } 1472 } 1473 } 1474 1475 // if not found, add to db 1476 bool new_to_le_device_db = false; 1477 if (le_db_index < 0) { 1478 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1479 new_to_le_device_db = true; 1480 } 1481 1482 if (le_db_index >= 0){ 1483 1484 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1485 if (!new_to_le_device_db){ 1486 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1487 } 1488 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1489 #else 1490 UNUSED(new_to_le_device_db); 1491 #endif 1492 1493 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1494 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1495 sm_conn->sm_le_db_index = le_db_index; 1496 1497 #ifdef ENABLE_LE_SIGNED_WRITE 1498 // store local CSRK 1499 setup->sm_le_device_index = le_db_index; 1500 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1501 log_info("sm: store local CSRK"); 1502 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1503 le_device_db_local_counter_set(le_db_index, 0); 1504 } 1505 1506 // store remote CSRK 1507 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1508 log_info("sm: store remote CSRK"); 1509 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1510 le_device_db_remote_counter_set(le_db_index, 0); 1511 } 1512 #endif 1513 // store encryption information for secure connections: LTK generated by ECDH 1514 if (setup->sm_use_secure_connections){ 1515 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1516 uint8_t zero_rand[8]; 1517 memset(zero_rand, 0, 8); 1518 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1519 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1520 } 1521 1522 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1523 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1524 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1525 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1526 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1527 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1528 1529 } 1530 } 1531 } 1532 1533 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1534 sm_conn->sm_pairing_failed_reason = reason; 1535 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1536 } 1537 1538 static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){ 1539 return 0; 1540 } 1541 1542 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1543 1544 // abort pairing if received keys are not valid 1545 uint8_t reason = sm_key_distribution_validate_received(sm_conn); 1546 if (reason != 0){ 1547 sm_pairing_error(sm_conn, reason); 1548 return; 1549 } 1550 1551 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1552 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1553 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1554 & SM_AUTHREQ_BONDING ) != 0u; 1555 1556 if (bonding_enabled){ 1557 sm_store_bonding_information(sm_conn); 1558 } else { 1559 log_info("Ignoring received keys, bonding not enabled"); 1560 } 1561 } 1562 1563 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1564 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1565 } 1566 1567 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1568 1569 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1570 static int sm_passkey_used(stk_generation_method_t method); 1571 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1572 1573 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1574 if (setup->sm_stk_generation_method == OOB){ 1575 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1576 } else { 1577 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); 1578 } 1579 } 1580 1581 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1582 if (IS_RESPONDER(sm_conn->sm_role)){ 1583 // Responder 1584 if (setup->sm_stk_generation_method == OOB){ 1585 // generate Nb 1586 log_info("Generate Nb"); 1587 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); 1588 } else { 1589 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1590 } 1591 } else { 1592 // Initiator role 1593 switch (setup->sm_stk_generation_method){ 1594 case JUST_WORKS: 1595 sm_sc_prepare_dhkey_check(sm_conn); 1596 break; 1597 1598 case NUMERIC_COMPARISON: 1599 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1600 break; 1601 case PK_INIT_INPUT: 1602 case PK_RESP_INPUT: 1603 case PK_BOTH_INPUT: 1604 if (setup->sm_passkey_bit < 20u) { 1605 sm_sc_start_calculating_local_confirm(sm_conn); 1606 } else { 1607 sm_sc_prepare_dhkey_check(sm_conn); 1608 } 1609 break; 1610 case OOB: 1611 sm_sc_prepare_dhkey_check(sm_conn); 1612 break; 1613 default: 1614 btstack_assert(false); 1615 break; 1616 } 1617 } 1618 } 1619 1620 static void sm_sc_cmac_done(uint8_t * hash){ 1621 log_info("sm_sc_cmac_done: "); 1622 log_info_hexdump(hash, 16); 1623 1624 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1625 sm_sc_oob_state = SM_SC_OOB_IDLE; 1626 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1627 return; 1628 } 1629 1630 sm_connection_t * sm_conn = sm_cmac_connection; 1631 sm_cmac_connection = NULL; 1632 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1633 link_key_type_t link_key_type; 1634 #endif 1635 1636 switch (sm_conn->sm_engine_state){ 1637 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1638 (void)memcpy(setup->sm_local_confirm, hash, 16); 1639 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1640 break; 1641 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1642 // check 1643 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1644 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1645 break; 1646 } 1647 sm_sc_state_after_receiving_random(sm_conn); 1648 break; 1649 case SM_SC_W4_CALCULATE_G2: { 1650 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1651 big_endian_store_32(setup->sm_tk, 12, vab); 1652 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1653 sm_trigger_user_response(sm_conn); 1654 break; 1655 } 1656 case SM_SC_W4_CALCULATE_F5_SALT: 1657 (void)memcpy(setup->sm_t, hash, 16); 1658 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1659 break; 1660 case SM_SC_W4_CALCULATE_F5_MACKEY: 1661 (void)memcpy(setup->sm_mackey, hash, 16); 1662 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1663 break; 1664 case SM_SC_W4_CALCULATE_F5_LTK: 1665 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1666 // Errata Service Release to the Bluetooth Specification: ESR09 1667 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1668 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1669 (void)memcpy(setup->sm_ltk, hash, 16); 1670 (void)memcpy(setup->sm_local_ltk, hash, 16); 1671 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1672 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1673 break; 1674 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1675 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1676 if (IS_RESPONDER(sm_conn->sm_role)){ 1677 // responder 1678 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1679 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1680 } else { 1681 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1682 } 1683 } else { 1684 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1685 } 1686 break; 1687 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1688 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1689 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1690 break; 1691 } 1692 if (IS_RESPONDER(sm_conn->sm_role)){ 1693 // responder 1694 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1695 } else { 1696 // initiator 1697 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1698 } 1699 break; 1700 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1701 case SM_SC_W4_CALCULATE_ILK: 1702 (void)memcpy(setup->sm_t, hash, 16); 1703 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1704 break; 1705 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1706 reverse_128(hash, setup->sm_t); 1707 link_key_type = sm_conn->sm_connection_authenticated ? 1708 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1709 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1710 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1711 if (IS_RESPONDER(sm_conn->sm_role)){ 1712 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1713 } else { 1714 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1715 } 1716 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1717 sm_done_for_handle(sm_conn->sm_handle); 1718 break; 1719 case SM_BR_EDR_W4_CALCULATE_ILK: 1720 (void)memcpy(setup->sm_t, hash, 16); 1721 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1722 break; 1723 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1724 log_info("Derived LE LTK from BR/EDR Link Key"); 1725 log_info_key("Link Key", hash); 1726 (void)memcpy(setup->sm_ltk, hash, 16); 1727 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1728 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1729 sm_store_bonding_information(sm_conn); 1730 sm_done_for_handle(sm_conn->sm_handle); 1731 break; 1732 #endif 1733 default: 1734 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1735 break; 1736 } 1737 sm_trigger_run(); 1738 } 1739 1740 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){ 1741 const uint16_t message_len = 65; 1742 sm_cmac_connection = sm_conn; 1743 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1744 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1745 sm_cmac_sc_buffer[64] = z; 1746 log_info("f4 key"); 1747 log_info_hexdump(x, 16); 1748 log_info("f4 message"); 1749 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1750 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1751 } 1752 1753 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1754 static const uint8_t f5_length[] = { 0x01, 0x00}; 1755 1756 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1757 1758 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1759 1760 log_info("f5_calculate_salt"); 1761 // calculate salt for f5 1762 const uint16_t message_len = 32; 1763 sm_cmac_connection = sm_conn; 1764 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1765 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1766 } 1767 1768 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){ 1769 const uint16_t message_len = 53; 1770 sm_cmac_connection = sm_conn; 1771 1772 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1773 sm_cmac_sc_buffer[0] = 0; 1774 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1775 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1776 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1777 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1778 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1779 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1780 log_info("f5 key"); 1781 log_info_hexdump(t, 16); 1782 log_info("f5 message for MacKey"); 1783 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1784 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1785 } 1786 1787 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1788 sm_key56_t bd_addr_master, bd_addr_slave; 1789 bd_addr_master[0] = setup->sm_m_addr_type; 1790 bd_addr_slave[0] = setup->sm_s_addr_type; 1791 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1792 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1793 if (IS_RESPONDER(sm_conn->sm_role)){ 1794 // responder 1795 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1796 } else { 1797 // initiator 1798 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1799 } 1800 } 1801 1802 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1803 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1804 const uint16_t message_len = 53; 1805 sm_cmac_connection = sm_conn; 1806 sm_cmac_sc_buffer[0] = 1; 1807 // 1..52 setup before 1808 log_info("f5 key"); 1809 log_info_hexdump(t, 16); 1810 log_info("f5 message for LTK"); 1811 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1812 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1813 } 1814 1815 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1816 f5_ltk(sm_conn, setup->sm_t); 1817 } 1818 1819 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){ 1820 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1821 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1822 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1823 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1824 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1825 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1826 } 1827 1828 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1829 const uint16_t message_len = 65; 1830 sm_cmac_connection = sm_conn; 1831 log_info("f6 key"); 1832 log_info_hexdump(w, 16); 1833 log_info("f6 message"); 1834 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1835 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1836 } 1837 1838 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1839 // - U is 256 bits 1840 // - V is 256 bits 1841 // - X is 128 bits 1842 // - Y is 128 bits 1843 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){ 1844 const uint16_t message_len = 80; 1845 sm_cmac_connection = sm_conn; 1846 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1847 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1848 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1849 log_info("g2 key"); 1850 log_info_hexdump(x, 16); 1851 log_info("g2 message"); 1852 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1853 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1854 } 1855 1856 static void g2_calculate(sm_connection_t * sm_conn) { 1857 // calc Va if numeric comparison 1858 if (IS_RESPONDER(sm_conn->sm_role)){ 1859 // responder 1860 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1861 } else { 1862 // initiator 1863 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1864 } 1865 } 1866 1867 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1868 uint8_t z = 0; 1869 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1870 // some form of passkey 1871 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1872 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1873 setup->sm_passkey_bit++; 1874 } 1875 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1876 } 1877 1878 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1879 // OOB 1880 if (setup->sm_stk_generation_method == OOB){ 1881 if (IS_RESPONDER(sm_conn->sm_role)){ 1882 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1883 } else { 1884 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1885 } 1886 return; 1887 } 1888 1889 uint8_t z = 0; 1890 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1891 // some form of passkey 1892 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1893 // sm_passkey_bit was increased before sending confirm value 1894 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1895 } 1896 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1897 } 1898 1899 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1900 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1901 1902 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1903 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1904 return; 1905 } else { 1906 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1907 } 1908 } 1909 1910 static void sm_sc_dhkey_calculated(void * arg){ 1911 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1912 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1913 if (sm_conn == NULL) return; 1914 1915 log_info("dhkey"); 1916 log_info_hexdump(&setup->sm_dhkey[0], 32); 1917 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1918 // trigger next step 1919 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1920 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1921 } 1922 sm_trigger_run(); 1923 } 1924 1925 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1926 // calculate DHKCheck 1927 sm_key56_t bd_addr_master, bd_addr_slave; 1928 bd_addr_master[0] = setup->sm_m_addr_type; 1929 bd_addr_slave[0] = setup->sm_s_addr_type; 1930 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1931 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1932 uint8_t iocap_a[3]; 1933 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1934 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1935 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1936 uint8_t iocap_b[3]; 1937 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1938 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1939 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1940 if (IS_RESPONDER(sm_conn->sm_role)){ 1941 // responder 1942 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1943 f6_engine(sm_conn, setup->sm_mackey); 1944 } else { 1945 // initiator 1946 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1947 f6_engine(sm_conn, setup->sm_mackey); 1948 } 1949 } 1950 1951 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1952 // validate E = f6() 1953 sm_key56_t bd_addr_master, bd_addr_slave; 1954 bd_addr_master[0] = setup->sm_m_addr_type; 1955 bd_addr_slave[0] = setup->sm_s_addr_type; 1956 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1957 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1958 1959 uint8_t iocap_a[3]; 1960 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1961 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1962 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1963 uint8_t iocap_b[3]; 1964 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1965 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1966 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1967 if (IS_RESPONDER(sm_conn->sm_role)){ 1968 // responder 1969 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1970 f6_engine(sm_conn, setup->sm_mackey); 1971 } else { 1972 // initiator 1973 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1974 f6_engine(sm_conn, setup->sm_mackey); 1975 } 1976 } 1977 1978 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1979 1980 // 1981 // Link Key Conversion Function h6 1982 // 1983 // h6(W, keyID) = AES-CMAC_W(keyID) 1984 // - W is 128 bits 1985 // - keyID is 32 bits 1986 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1987 const uint16_t message_len = 4; 1988 sm_cmac_connection = sm_conn; 1989 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1990 log_info("h6 key"); 1991 log_info_hexdump(w, 16); 1992 log_info("h6 message"); 1993 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1994 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1995 } 1996 // 1997 // Link Key Conversion Function h7 1998 // 1999 // h7(SALT, W) = AES-CMAC_SALT(W) 2000 // - SALT is 128 bits 2001 // - W is 128 bits 2002 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 2003 const uint16_t message_len = 16; 2004 sm_cmac_connection = sm_conn; 2005 log_info("h7 key"); 2006 log_info_hexdump(salt, 16); 2007 log_info("h7 message"); 2008 log_info_hexdump(w, 16); 2009 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 2010 } 2011 2012 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2013 // Errata Service Release to the Bluetooth Specification: ESR09 2014 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2015 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2016 2017 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2018 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2019 } 2020 2021 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2022 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2023 } 2024 2025 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2026 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2027 } 2028 2029 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2030 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2031 } 2032 2033 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2034 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2035 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2036 } 2037 2038 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2039 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2040 h7_engine(sm_conn, salt, setup->sm_link_key); 2041 } 2042 2043 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2044 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2045 btstack_assert(hci_connection != NULL); 2046 reverse_128(hci_connection->link_key, setup->sm_link_key); 2047 setup->sm_link_key_type = hci_connection->link_key_type; 2048 } 2049 2050 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2051 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; 2052 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2053 } 2054 2055 #endif 2056 2057 #endif 2058 2059 // key management legacy connections: 2060 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2061 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2062 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2063 // - responder reconnects: responder uses LTK receveived from master 2064 2065 // key management secure connections: 2066 // - both devices store same LTK from ECDH key exchange. 2067 2068 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2069 static void sm_load_security_info(sm_connection_t * sm_connection){ 2070 int encryption_key_size; 2071 int authenticated; 2072 int authorized; 2073 int secure_connection; 2074 2075 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2076 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2077 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2078 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); 2079 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2080 sm_connection->sm_connection_authenticated = authenticated; 2081 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2082 sm_connection->sm_connection_sc = secure_connection; 2083 } 2084 #endif 2085 2086 #ifdef ENABLE_LE_PERIPHERAL 2087 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2088 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2089 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2090 // re-establish used key encryption size 2091 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2092 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2093 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2094 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2095 // Legacy paring -> not SC 2096 sm_connection->sm_connection_sc = 0; 2097 log_info("sm: received ltk request with key size %u, authenticated %u", 2098 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2099 } 2100 #endif 2101 2102 // distributed key generation 2103 static bool sm_run_dpkg(void){ 2104 switch (dkg_state){ 2105 case DKG_CALC_IRK: 2106 // already busy? 2107 if (sm_aes128_state == SM_AES128_IDLE) { 2108 log_info("DKG_CALC_IRK started"); 2109 // IRK = d1(IR, 1, 0) 2110 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2111 sm_aes128_state = SM_AES128_ACTIVE; 2112 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2113 return true; 2114 } 2115 break; 2116 case DKG_CALC_DHK: 2117 // already busy? 2118 if (sm_aes128_state == SM_AES128_IDLE) { 2119 log_info("DKG_CALC_DHK started"); 2120 // DHK = d1(IR, 3, 0) 2121 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2122 sm_aes128_state = SM_AES128_ACTIVE; 2123 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2124 return true; 2125 } 2126 break; 2127 default: 2128 break; 2129 } 2130 return false; 2131 } 2132 2133 // random address updates 2134 static bool sm_run_rau(void){ 2135 switch (rau_state){ 2136 case RAU_GET_RANDOM: 2137 rau_state = RAU_W4_RANDOM; 2138 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2139 return true; 2140 case RAU_GET_ENC: 2141 // already busy? 2142 if (sm_aes128_state == SM_AES128_IDLE) { 2143 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2144 sm_aes128_state = SM_AES128_ACTIVE; 2145 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2146 return true; 2147 } 2148 break; 2149 default: 2150 break; 2151 } 2152 return false; 2153 } 2154 2155 // CSRK Lookup 2156 static bool sm_run_csrk(void){ 2157 btstack_linked_list_iterator_t it; 2158 2159 // -- if csrk lookup ready, find connection that require csrk lookup 2160 if (sm_address_resolution_idle()){ 2161 hci_connections_get_iterator(&it); 2162 while(btstack_linked_list_iterator_has_next(&it)){ 2163 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2164 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2165 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2166 // and start lookup 2167 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); 2168 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2169 break; 2170 } 2171 } 2172 } 2173 2174 // -- if csrk lookup ready, resolved addresses for received addresses 2175 if (sm_address_resolution_idle()) { 2176 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2177 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2178 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2179 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2180 btstack_memory_sm_lookup_entry_free(entry); 2181 } 2182 } 2183 2184 // -- Continue with CSRK device lookup by public or resolvable private address 2185 if (!sm_address_resolution_idle()){ 2186 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2187 while (sm_address_resolution_test < le_device_db_max_count()){ 2188 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2189 bd_addr_t addr; 2190 sm_key_t irk; 2191 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2192 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2193 2194 // skip unused entries 2195 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2196 sm_address_resolution_test++; 2197 continue; 2198 } 2199 2200 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2201 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2202 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2203 break; 2204 } 2205 2206 // if connection type is public, it must be a different one 2207 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2208 sm_address_resolution_test++; 2209 continue; 2210 } 2211 2212 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2213 2214 log_info("LE Device Lookup: calculate AH"); 2215 log_info_key("IRK", irk); 2216 2217 (void)memcpy(sm_aes128_key, irk, 16); 2218 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2219 sm_address_resolution_ah_calculation_active = 1; 2220 sm_aes128_state = SM_AES128_ACTIVE; 2221 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2222 return true; 2223 } 2224 2225 if (sm_address_resolution_test >= le_device_db_max_count()){ 2226 log_info("LE Device Lookup: not found"); 2227 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2228 } 2229 } 2230 return false; 2231 } 2232 2233 // SC OOB 2234 static bool sm_run_oob(void){ 2235 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2236 switch (sm_sc_oob_state){ 2237 case SM_SC_OOB_W2_CALC_CONFIRM: 2238 if (!sm_cmac_ready()) break; 2239 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2240 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2241 return true; 2242 default: 2243 break; 2244 } 2245 #endif 2246 return false; 2247 } 2248 2249 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2250 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2251 } 2252 2253 // handle basic actions that don't requires the full context 2254 static bool sm_run_basic(void){ 2255 btstack_linked_list_iterator_t it; 2256 hci_connections_get_iterator(&it); 2257 while(btstack_linked_list_iterator_has_next(&it)){ 2258 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2259 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2260 switch(sm_connection->sm_engine_state){ 2261 2262 // general 2263 case SM_GENERAL_SEND_PAIRING_FAILED: { 2264 uint8_t buffer[2]; 2265 buffer[0] = SM_CODE_PAIRING_FAILED; 2266 buffer[1] = sm_connection->sm_pairing_failed_reason; 2267 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2268 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2269 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2270 sm_done_for_handle(sm_connection->sm_handle); 2271 break; 2272 } 2273 2274 // responder side 2275 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2276 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2277 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2278 return true; 2279 2280 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2281 case SM_SC_RECEIVED_LTK_REQUEST: 2282 switch (sm_connection->sm_irk_lookup_state){ 2283 case IRK_LOOKUP_FAILED: 2284 log_info("LTK Request: IRK Lookup Failed)"); 2285 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2286 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2287 return true; 2288 default: 2289 break; 2290 } 2291 break; 2292 #endif 2293 default: 2294 break; 2295 } 2296 } 2297 return false; 2298 } 2299 2300 static void sm_run_activate_connection(void){ 2301 // Find connections that requires setup context and make active if no other is locked 2302 btstack_linked_list_iterator_t it; 2303 hci_connections_get_iterator(&it); 2304 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2305 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2306 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2307 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2308 bool done = true; 2309 int err; 2310 UNUSED(err); 2311 2312 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2313 // assert ec key is ready 2314 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2315 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2316 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2317 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2318 sm_ec_generate_new_key(); 2319 } 2320 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2321 continue; 2322 } 2323 } 2324 #endif 2325 2326 switch (sm_connection->sm_engine_state) { 2327 #ifdef ENABLE_LE_PERIPHERAL 2328 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2329 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2330 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2331 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2332 case SM_SC_RECEIVED_LTK_REQUEST: 2333 #endif 2334 #endif 2335 #ifdef ENABLE_LE_CENTRAL 2336 case SM_INITIATOR_PH4_HAS_LTK: 2337 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2338 #endif 2339 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2340 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2341 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2342 #endif 2343 // just lock context 2344 break; 2345 default: 2346 done = false; 2347 break; 2348 } 2349 if (done){ 2350 sm_active_connection_handle = sm_connection->sm_handle; 2351 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); 2352 } 2353 } 2354 } 2355 2356 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2357 int i; 2358 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2359 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2360 uint8_t action = 0; 2361 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2362 if (flags & (1u<<i)){ 2363 bool clear_flag = true; 2364 switch (i){ 2365 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2366 case SM_KEYPRESS_PASSKEY_CLEARED: 2367 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2368 default: 2369 break; 2370 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2371 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2372 num_actions--; 2373 clear_flag = num_actions == 0u; 2374 break; 2375 } 2376 if (clear_flag){ 2377 flags &= ~(1<<i); 2378 } 2379 action = i; 2380 break; 2381 } 2382 } 2383 setup->sm_keypress_notification = (num_actions << 5) | flags; 2384 2385 // send keypress notification 2386 uint8_t buffer[2]; 2387 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2388 buffer[1] = action; 2389 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2390 2391 // try 2392 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2393 } 2394 2395 static void sm_run_distribute_keys(sm_connection_t * connection){ 2396 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2397 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2398 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2399 uint8_t buffer[17]; 2400 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2401 reverse_128(setup->sm_ltk, &buffer[1]); 2402 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2403 sm_timeout_reset(connection); 2404 return; 2405 } 2406 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2407 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2408 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2409 uint8_t buffer[11]; 2410 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2411 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2412 reverse_64(setup->sm_local_rand, &buffer[3]); 2413 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2414 sm_timeout_reset(connection); 2415 return; 2416 } 2417 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2418 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2419 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2420 uint8_t buffer[17]; 2421 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2422 reverse_128(sm_persistent_irk, &buffer[1]); 2423 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2424 sm_timeout_reset(connection); 2425 return; 2426 } 2427 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2428 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2429 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2430 bd_addr_t local_address; 2431 uint8_t buffer[8]; 2432 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2433 switch (gap_random_address_get_mode()){ 2434 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2435 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2436 // public or static random 2437 gap_le_get_own_address(&buffer[1], local_address); 2438 break; 2439 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2440 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2441 // fallback to public 2442 gap_local_bd_addr(local_address); 2443 buffer[1] = 0; 2444 break; 2445 default: 2446 btstack_assert(false); 2447 break; 2448 } 2449 reverse_bd_addr(local_address, &buffer[2]); 2450 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2451 sm_timeout_reset(connection); 2452 return; 2453 } 2454 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2455 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2456 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2457 2458 #ifdef ENABLE_LE_SIGNED_WRITE 2459 // hack to reproduce test runs 2460 if (test_use_fixed_local_csrk){ 2461 memset(setup->sm_local_csrk, 0xcc, 16); 2462 } 2463 2464 // store local CSRK 2465 if (setup->sm_le_device_index >= 0){ 2466 log_info("sm: store local CSRK"); 2467 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2468 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2469 } 2470 #endif 2471 2472 uint8_t buffer[17]; 2473 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2474 reverse_128(setup->sm_local_csrk, &buffer[1]); 2475 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2476 sm_timeout_reset(connection); 2477 return; 2478 } 2479 btstack_assert(false); 2480 } 2481 2482 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2483 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2484 // requirements to derive link key from LE: 2485 // - use secure connections 2486 if (setup->sm_use_secure_connections == 0) return false; 2487 // - bonding needs to be enabled: 2488 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; 2489 if (!bonding_enabled) return false; 2490 // - need identity address / public addr 2491 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2492 if (!have_identity_address_info) return false; 2493 // - 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) 2494 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2495 // If SC is authenticated, we consider it safe to overwrite a stored key. 2496 // 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. 2497 uint8_t link_key[16]; 2498 link_key_type_t link_key_type; 2499 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2500 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2501 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2502 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2503 return false; 2504 } 2505 // get started (all of the above are true) 2506 return true; 2507 #else 2508 UNUSED(sm_connection); 2509 return false; 2510 #endif 2511 } 2512 2513 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2514 if (sm_ctkd_from_le(connection)){ 2515 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; 2516 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2517 } else { 2518 connection->sm_engine_state = SM_RESPONDER_IDLE; 2519 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2520 sm_done_for_handle(connection->sm_handle); 2521 } 2522 } 2523 2524 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2525 if (sm_ctkd_from_le(connection)){ 2526 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; 2527 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2528 } else { 2529 sm_master_pairing_success(connection); 2530 } 2531 } 2532 2533 static void sm_run(void){ 2534 2535 // assert that stack has already bootet 2536 if (hci_get_state() != HCI_STATE_WORKING) return; 2537 2538 // assert that we can send at least commands 2539 if (!hci_can_send_command_packet_now()) return; 2540 2541 // pause until IR/ER are ready 2542 if (sm_persistent_keys_random_active) return; 2543 2544 bool done; 2545 2546 // 2547 // non-connection related behaviour 2548 // 2549 2550 done = sm_run_dpkg(); 2551 if (done) return; 2552 2553 done = sm_run_rau(); 2554 if (done) return; 2555 2556 done = sm_run_csrk(); 2557 if (done) return; 2558 2559 done = sm_run_oob(); 2560 if (done) return; 2561 2562 // assert that we can send at least commands - cmd might have been sent by crypto engine 2563 if (!hci_can_send_command_packet_now()) return; 2564 2565 // handle basic actions that don't requires the full context 2566 done = sm_run_basic(); 2567 if (done) return; 2568 2569 // 2570 // active connection handling 2571 // -- use loop to handle next connection if lock on setup context is released 2572 2573 while (true) { 2574 2575 sm_run_activate_connection(); 2576 2577 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2578 2579 // 2580 // active connection handling 2581 // 2582 2583 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2584 if (!connection) { 2585 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2586 return; 2587 } 2588 2589 // assert that we could send a SM PDU - not needed for all of the following 2590 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2591 log_info("cannot send now, requesting can send now event"); 2592 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2593 return; 2594 } 2595 2596 // send keypress notifications 2597 if (setup->sm_keypress_notification){ 2598 sm_run_send_keypress_notification(connection); 2599 return; 2600 } 2601 2602 int key_distribution_flags; 2603 UNUSED(key_distribution_flags); 2604 #ifdef ENABLE_LE_PERIPHERAL 2605 int err; 2606 bool have_ltk; 2607 uint8_t ltk[16]; 2608 #endif 2609 2610 log_info("sm_run: state %u", connection->sm_engine_state); 2611 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2612 log_info("sm_run // cannot send"); 2613 } 2614 switch (connection->sm_engine_state){ 2615 2616 // secure connections, initiator + responding states 2617 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2618 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2619 if (!sm_cmac_ready()) break; 2620 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2621 sm_sc_calculate_local_confirm(connection); 2622 break; 2623 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2624 if (!sm_cmac_ready()) break; 2625 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2626 sm_sc_calculate_remote_confirm(connection); 2627 break; 2628 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2629 if (!sm_cmac_ready()) break; 2630 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2631 sm_sc_calculate_f6_for_dhkey_check(connection); 2632 break; 2633 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2634 if (!sm_cmac_ready()) break; 2635 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2636 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2637 break; 2638 case SM_SC_W2_CALCULATE_F5_SALT: 2639 if (!sm_cmac_ready()) break; 2640 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2641 f5_calculate_salt(connection); 2642 break; 2643 case SM_SC_W2_CALCULATE_F5_MACKEY: 2644 if (!sm_cmac_ready()) break; 2645 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2646 f5_calculate_mackey(connection); 2647 break; 2648 case SM_SC_W2_CALCULATE_F5_LTK: 2649 if (!sm_cmac_ready()) break; 2650 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2651 f5_calculate_ltk(connection); 2652 break; 2653 case SM_SC_W2_CALCULATE_G2: 2654 if (!sm_cmac_ready()) break; 2655 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2656 g2_calculate(connection); 2657 break; 2658 #endif 2659 2660 #ifdef ENABLE_LE_CENTRAL 2661 // initiator side 2662 2663 case SM_INITIATOR_PH4_HAS_LTK: { 2664 sm_reset_setup(); 2665 sm_load_security_info(connection); 2666 sm_reencryption_started(connection); 2667 2668 sm_key_t peer_ltk_flipped; 2669 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2670 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2671 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2672 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2673 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2674 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2675 return; 2676 } 2677 2678 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2679 sm_reset_setup(); 2680 sm_init_setup(connection); 2681 sm_timeout_start(connection); 2682 sm_pairing_started(connection); 2683 2684 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2685 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2686 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2687 sm_timeout_reset(connection); 2688 break; 2689 #endif 2690 2691 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2692 2693 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2694 bool trigger_user_response = false; 2695 bool trigger_start_calculating_local_confirm = false; 2696 uint8_t buffer[65]; 2697 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2698 // 2699 reverse_256(&ec_q[0], &buffer[1]); 2700 reverse_256(&ec_q[32], &buffer[33]); 2701 2702 #ifdef ENABLE_TESTING_SUPPORT 2703 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2704 log_info("testing_support: invalidating public key"); 2705 // flip single bit of public key coordinate 2706 buffer[1] ^= 1; 2707 } 2708 #endif 2709 2710 // stk generation method 2711 // passkey entry: notify app to show passkey or to request passkey 2712 switch (setup->sm_stk_generation_method){ 2713 case JUST_WORKS: 2714 case NUMERIC_COMPARISON: 2715 if (IS_RESPONDER(connection->sm_role)){ 2716 // responder 2717 trigger_start_calculating_local_confirm = true; 2718 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2719 } else { 2720 // initiator 2721 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2722 } 2723 break; 2724 case PK_INIT_INPUT: 2725 case PK_RESP_INPUT: 2726 case PK_BOTH_INPUT: 2727 // use random TK for display 2728 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2729 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2730 setup->sm_passkey_bit = 0; 2731 2732 if (IS_RESPONDER(connection->sm_role)){ 2733 // responder 2734 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2735 } else { 2736 // initiator 2737 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2738 } 2739 trigger_user_response = true; 2740 break; 2741 case OOB: 2742 if (IS_RESPONDER(connection->sm_role)){ 2743 // responder 2744 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2745 } else { 2746 // initiator 2747 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2748 } 2749 break; 2750 default: 2751 btstack_assert(false); 2752 break; 2753 } 2754 2755 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2756 sm_timeout_reset(connection); 2757 2758 // trigger user response and calc confirm after sending pdu 2759 if (trigger_user_response){ 2760 sm_trigger_user_response(connection); 2761 } 2762 if (trigger_start_calculating_local_confirm){ 2763 sm_sc_start_calculating_local_confirm(connection); 2764 } 2765 break; 2766 } 2767 case SM_SC_SEND_CONFIRMATION: { 2768 uint8_t buffer[17]; 2769 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2770 reverse_128(setup->sm_local_confirm, &buffer[1]); 2771 if (IS_RESPONDER(connection->sm_role)){ 2772 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2773 } else { 2774 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2775 } 2776 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2777 sm_timeout_reset(connection); 2778 break; 2779 } 2780 case SM_SC_SEND_PAIRING_RANDOM: { 2781 uint8_t buffer[17]; 2782 buffer[0] = SM_CODE_PAIRING_RANDOM; 2783 reverse_128(setup->sm_local_nonce, &buffer[1]); 2784 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2785 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2786 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2787 if (IS_RESPONDER(connection->sm_role)){ 2788 // responder 2789 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2790 } else { 2791 // initiator 2792 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2793 } 2794 } else { 2795 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2796 if (IS_RESPONDER(connection->sm_role)){ 2797 // responder 2798 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2799 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2800 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2801 } else { 2802 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2803 sm_sc_prepare_dhkey_check(connection); 2804 } 2805 } else { 2806 // initiator 2807 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2808 } 2809 } 2810 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2811 sm_timeout_reset(connection); 2812 break; 2813 } 2814 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2815 uint8_t buffer[17]; 2816 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2817 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2818 2819 if (IS_RESPONDER(connection->sm_role)){ 2820 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2821 } else { 2822 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2823 } 2824 2825 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2826 sm_timeout_reset(connection); 2827 break; 2828 } 2829 2830 #endif 2831 2832 #ifdef ENABLE_LE_PERIPHERAL 2833 2834 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2835 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2836 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2837 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2838 sm_timeout_start(connection); 2839 break; 2840 } 2841 2842 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2843 case SM_SC_RECEIVED_LTK_REQUEST: 2844 switch (connection->sm_irk_lookup_state){ 2845 case IRK_LOOKUP_SUCCEEDED: 2846 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2847 // start using context by loading security info 2848 sm_reset_setup(); 2849 sm_load_security_info(connection); 2850 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2851 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2852 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2853 sm_reencryption_started(connection); 2854 sm_trigger_run(); 2855 break; 2856 } 2857 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2858 connection->sm_engine_state = SM_RESPONDER_IDLE; 2859 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2860 return; 2861 default: 2862 // just wait until IRK lookup is completed 2863 break; 2864 } 2865 break; 2866 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2867 2868 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2869 sm_reset_setup(); 2870 2871 // handle Pairing Request with LTK available 2872 switch (connection->sm_irk_lookup_state) { 2873 case IRK_LOOKUP_SUCCEEDED: 2874 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2875 have_ltk = !sm_is_null_key(ltk); 2876 if (have_ltk){ 2877 log_info("pairing request but LTK available"); 2878 // emit re-encryption start/fail sequence 2879 sm_reencryption_started(connection); 2880 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2881 } 2882 break; 2883 default: 2884 break; 2885 } 2886 2887 sm_init_setup(connection); 2888 sm_pairing_started(connection); 2889 2890 // recover pairing request 2891 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2892 err = sm_stk_generation_init(connection); 2893 2894 #ifdef ENABLE_TESTING_SUPPORT 2895 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2896 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2897 err = test_pairing_failure; 2898 } 2899 #endif 2900 if (err != 0){ 2901 sm_pairing_error(connection, err); 2902 sm_trigger_run(); 2903 break; 2904 } 2905 2906 sm_timeout_start(connection); 2907 2908 // generate random number first, if we need to show passkey, otherwise send response 2909 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2910 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2911 break; 2912 } 2913 2914 /* fall through */ 2915 2916 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2917 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2918 2919 // start with initiator key dist flags 2920 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2921 2922 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2923 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2924 if (setup->sm_use_secure_connections){ 2925 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2926 } 2927 #endif 2928 // setup in response 2929 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); 2930 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); 2931 2932 // update key distribution after ENC was dropped 2933 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)); 2934 2935 if (setup->sm_use_secure_connections){ 2936 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2937 } else { 2938 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2939 } 2940 2941 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2942 sm_timeout_reset(connection); 2943 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2944 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2945 sm_trigger_user_response(connection); 2946 } 2947 return; 2948 #endif 2949 2950 case SM_PH2_SEND_PAIRING_RANDOM: { 2951 uint8_t buffer[17]; 2952 buffer[0] = SM_CODE_PAIRING_RANDOM; 2953 reverse_128(setup->sm_local_random, &buffer[1]); 2954 if (IS_RESPONDER(connection->sm_role)){ 2955 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2956 } else { 2957 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2958 } 2959 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2960 sm_timeout_reset(connection); 2961 break; 2962 } 2963 2964 case SM_PH2_C1_GET_ENC_A: 2965 // already busy? 2966 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2967 // calculate confirm using aes128 engine - step 1 2968 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); 2969 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2970 sm_aes128_state = SM_AES128_ACTIVE; 2971 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); 2972 break; 2973 2974 case SM_PH2_C1_GET_ENC_C: 2975 // already busy? 2976 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2977 // calculate m_confirm using aes128 engine - step 1 2978 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); 2979 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2980 sm_aes128_state = SM_AES128_ACTIVE; 2981 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); 2982 break; 2983 2984 case SM_PH2_CALC_STK: 2985 // already busy? 2986 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2987 // calculate STK 2988 if (IS_RESPONDER(connection->sm_role)){ 2989 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2990 } else { 2991 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2992 } 2993 connection->sm_engine_state = SM_PH2_W4_STK; 2994 sm_aes128_state = SM_AES128_ACTIVE; 2995 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); 2996 break; 2997 2998 case SM_PH3_Y_GET_ENC: 2999 // already busy? 3000 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3001 // PH3B2 - calculate Y from - enc 3002 3003 // dm helper (was sm_dm_r_prime) 3004 // r' = padding || r 3005 // r - 64 bit value 3006 memset(&sm_aes128_plaintext[0], 0, 8); 3007 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3008 3009 // Y = dm(DHK, Rand) 3010 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3011 sm_aes128_state = SM_AES128_ACTIVE; 3012 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); 3013 break; 3014 3015 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3016 uint8_t buffer[17]; 3017 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3018 reverse_128(setup->sm_local_confirm, &buffer[1]); 3019 if (IS_RESPONDER(connection->sm_role)){ 3020 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3021 } else { 3022 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3023 } 3024 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3025 sm_timeout_reset(connection); 3026 return; 3027 } 3028 #ifdef ENABLE_LE_PERIPHERAL 3029 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3030 sm_key_t stk_flipped; 3031 reverse_128(setup->sm_ltk, stk_flipped); 3032 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3033 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3034 return; 3035 } 3036 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3037 // allow to override LTK 3038 if (sm_get_ltk_callback != NULL){ 3039 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3040 } 3041 sm_key_t ltk_flipped; 3042 reverse_128(setup->sm_ltk, ltk_flipped); 3043 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3044 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3045 return; 3046 } 3047 3048 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3049 // already busy? 3050 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3051 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3052 3053 sm_reset_setup(); 3054 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3055 3056 sm_reencryption_started(connection); 3057 3058 // dm helper (was sm_dm_r_prime) 3059 // r' = padding || r 3060 // r - 64 bit value 3061 memset(&sm_aes128_plaintext[0], 0, 8); 3062 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3063 3064 // Y = dm(DHK, Rand) 3065 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3066 sm_aes128_state = SM_AES128_ACTIVE; 3067 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); 3068 return; 3069 #endif 3070 #ifdef ENABLE_LE_CENTRAL 3071 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3072 sm_key_t stk_flipped; 3073 reverse_128(setup->sm_ltk, stk_flipped); 3074 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3075 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3076 return; 3077 } 3078 #endif 3079 3080 case SM_PH3_DISTRIBUTE_KEYS: 3081 // send next key 3082 if (setup->sm_key_distribution_send_set != 0){ 3083 sm_run_distribute_keys(connection); 3084 } 3085 3086 // more to send? 3087 if (setup->sm_key_distribution_send_set != 0){ 3088 return; 3089 } 3090 3091 // keys are sent 3092 if (IS_RESPONDER(connection->sm_role)){ 3093 // slave -> receive master keys if any 3094 if (sm_key_distribution_all_received()){ 3095 sm_key_distribution_handle_all_received(connection); 3096 sm_key_distribution_complete_responder(connection); 3097 // start CTKD right away 3098 continue; 3099 } else { 3100 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3101 } 3102 } else { 3103 sm_master_pairing_success(connection); 3104 } 3105 break; 3106 3107 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3108 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3109 // fill in sm setup (lite version of sm_init_setup) 3110 sm_reset_setup(); 3111 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3112 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3113 setup->sm_s_addr_type = connection->sm_own_addr_type; 3114 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3115 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3116 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3117 setup->sm_use_secure_connections = true; 3118 sm_ctkd_fetch_br_edr_link_key(connection); 3119 3120 // Enc Key and IRK if requested 3121 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3122 #ifdef ENABLE_LE_SIGNED_WRITE 3123 // Plus signing key if supported 3124 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3125 #endif 3126 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3127 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3128 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3129 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3130 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3131 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3132 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3133 3134 // set state and send pairing response 3135 sm_timeout_start(connection); 3136 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3137 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3138 break; 3139 3140 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3141 // fill in sm setup (lite version of sm_init_setup) 3142 sm_reset_setup(); 3143 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3144 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3145 setup->sm_s_addr_type = connection->sm_own_addr_type; 3146 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3147 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3148 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3149 setup->sm_use_secure_connections = true; 3150 sm_ctkd_fetch_br_edr_link_key(connection); 3151 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3152 3153 // Enc Key and IRK if requested 3154 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3155 #ifdef ENABLE_LE_SIGNED_WRITE 3156 // Plus signing key if supported 3157 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3158 #endif 3159 // drop flags not requested by initiator 3160 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3161 3162 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3163 // - the IO Capability field, 3164 // - the OOB data flag field, and 3165 // - all bits in the Auth Req field except the CT2 bit. 3166 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3167 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3168 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3169 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3170 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3171 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3172 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3173 3174 // configure key distribution, LTK is derived locally 3175 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3176 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3177 3178 // set state and send pairing response 3179 sm_timeout_start(connection); 3180 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3181 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3182 break; 3183 case SM_BR_EDR_DISTRIBUTE_KEYS: 3184 if (setup->sm_key_distribution_send_set != 0) { 3185 sm_run_distribute_keys(connection); 3186 return; 3187 } 3188 // keys are sent 3189 if (IS_RESPONDER(connection->sm_role)) { 3190 // responder -> receive master keys if there are any 3191 if (!sm_key_distribution_all_received()){ 3192 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3193 break; 3194 } 3195 } 3196 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3197 sm_ctkd_start_from_br_edr(connection); 3198 continue; 3199 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3200 if (!sm_cmac_ready()) break; 3201 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3202 h6_calculate_ilk_from_le_ltk(connection); 3203 break; 3204 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3205 if (!sm_cmac_ready()) break; 3206 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3207 h6_calculate_br_edr_link_key(connection); 3208 break; 3209 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3210 if (!sm_cmac_ready()) break; 3211 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3212 h7_calculate_ilk_from_le_ltk(connection); 3213 break; 3214 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3215 if (!sm_cmac_ready()) break; 3216 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3217 h6_calculate_ilk_from_br_edr(connection); 3218 break; 3219 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3220 if (!sm_cmac_ready()) break; 3221 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3222 h6_calculate_le_ltk(connection); 3223 break; 3224 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3225 if (!sm_cmac_ready()) break; 3226 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3227 h7_calculate_ilk_from_br_edr(connection); 3228 break; 3229 #endif 3230 3231 default: 3232 break; 3233 } 3234 3235 // check again if active connection was released 3236 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3237 } 3238 } 3239 3240 // sm_aes128_state stays active 3241 static void sm_handle_encryption_result_enc_a(void *arg){ 3242 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3243 sm_aes128_state = SM_AES128_IDLE; 3244 3245 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3246 if (connection == NULL) return; 3247 3248 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3249 sm_aes128_state = SM_AES128_ACTIVE; 3250 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); 3251 } 3252 3253 static void sm_handle_encryption_result_enc_b(void *arg){ 3254 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3255 sm_aes128_state = SM_AES128_IDLE; 3256 3257 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3258 if (connection == NULL) return; 3259 3260 log_info_key("c1!", setup->sm_local_confirm); 3261 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3262 sm_trigger_run(); 3263 } 3264 3265 // sm_aes128_state stays active 3266 static void sm_handle_encryption_result_enc_c(void *arg){ 3267 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3268 sm_aes128_state = SM_AES128_IDLE; 3269 3270 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3271 if (connection == NULL) return; 3272 3273 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3274 sm_aes128_state = SM_AES128_ACTIVE; 3275 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); 3276 } 3277 3278 static void sm_handle_encryption_result_enc_d(void * arg){ 3279 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3280 sm_aes128_state = SM_AES128_IDLE; 3281 3282 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3283 if (connection == NULL) return; 3284 3285 log_info_key("c1!", sm_aes128_ciphertext); 3286 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3287 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3288 sm_trigger_run(); 3289 return; 3290 } 3291 if (IS_RESPONDER(connection->sm_role)){ 3292 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3293 sm_trigger_run(); 3294 } else { 3295 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3296 sm_aes128_state = SM_AES128_ACTIVE; 3297 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); 3298 } 3299 } 3300 3301 static void sm_handle_encryption_result_enc_stk(void *arg){ 3302 sm_aes128_state = SM_AES128_IDLE; 3303 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3304 3305 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3306 if (connection == NULL) return; 3307 3308 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3309 log_info_key("stk", setup->sm_ltk); 3310 if (IS_RESPONDER(connection->sm_role)){ 3311 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3312 } else { 3313 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3314 } 3315 sm_trigger_run(); 3316 } 3317 3318 // sm_aes128_state stays active 3319 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3320 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3321 sm_aes128_state = SM_AES128_IDLE; 3322 3323 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3324 if (connection == NULL) return; 3325 3326 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3327 log_info_hex16("y", setup->sm_local_y); 3328 // PH3B3 - calculate EDIV 3329 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3330 log_info_hex16("ediv", setup->sm_local_ediv); 3331 // PH3B4 - calculate LTK - enc 3332 // LTK = d1(ER, DIV, 0)) 3333 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3334 sm_aes128_state = SM_AES128_ACTIVE; 3335 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); 3336 } 3337 3338 #ifdef ENABLE_LE_PERIPHERAL 3339 // sm_aes128_state stays active 3340 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3341 sm_aes128_state = SM_AES128_IDLE; 3342 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3343 3344 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3345 if (connection == NULL) return; 3346 3347 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3348 log_info_hex16("y", setup->sm_local_y); 3349 3350 // PH3B3 - calculate DIV 3351 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3352 log_info_hex16("ediv", setup->sm_local_ediv); 3353 // PH3B4 - calculate LTK - enc 3354 // LTK = d1(ER, DIV, 0)) 3355 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3356 sm_aes128_state = SM_AES128_ACTIVE; 3357 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); 3358 } 3359 #endif 3360 3361 // sm_aes128_state stays active 3362 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3363 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3364 sm_aes128_state = SM_AES128_IDLE; 3365 3366 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3367 if (connection == NULL) return; 3368 3369 log_info_key("ltk", setup->sm_ltk); 3370 // calc CSRK next 3371 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3372 sm_aes128_state = SM_AES128_ACTIVE; 3373 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); 3374 } 3375 3376 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3377 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3378 sm_aes128_state = SM_AES128_IDLE; 3379 3380 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3381 if (connection == NULL) return; 3382 3383 sm_aes128_state = SM_AES128_IDLE; 3384 log_info_key("csrk", setup->sm_local_csrk); 3385 if (setup->sm_key_distribution_send_set){ 3386 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3387 } else { 3388 // no keys to send, just continue 3389 if (IS_RESPONDER(connection->sm_role)){ 3390 if (sm_key_distribution_all_received()){ 3391 sm_key_distribution_handle_all_received(connection); 3392 sm_key_distribution_complete_responder(connection); 3393 } else { 3394 // slave -> receive master keys 3395 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3396 } 3397 } else { 3398 sm_key_distribution_complete_initiator(connection); 3399 } 3400 } 3401 sm_trigger_run(); 3402 } 3403 3404 #ifdef ENABLE_LE_PERIPHERAL 3405 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3406 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3407 sm_aes128_state = SM_AES128_IDLE; 3408 3409 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3410 if (connection == NULL) return; 3411 3412 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3413 log_info_key("ltk", setup->sm_ltk); 3414 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3415 sm_trigger_run(); 3416 } 3417 #endif 3418 3419 static void sm_handle_encryption_result_address_resolution(void *arg){ 3420 UNUSED(arg); 3421 sm_aes128_state = SM_AES128_IDLE; 3422 3423 sm_address_resolution_ah_calculation_active = 0; 3424 // compare calulated address against connecting device 3425 uint8_t * hash = &sm_aes128_ciphertext[13]; 3426 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3427 log_info("LE Device Lookup: matched resolvable private address"); 3428 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3429 sm_trigger_run(); 3430 return; 3431 } 3432 // no match, try next 3433 sm_address_resolution_test++; 3434 sm_trigger_run(); 3435 } 3436 3437 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3438 UNUSED(arg); 3439 sm_aes128_state = SM_AES128_IDLE; 3440 3441 log_info_key("irk", sm_persistent_irk); 3442 dkg_state = DKG_CALC_DHK; 3443 sm_trigger_run(); 3444 } 3445 3446 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3447 UNUSED(arg); 3448 sm_aes128_state = SM_AES128_IDLE; 3449 3450 log_info_key("dhk", sm_persistent_dhk); 3451 dkg_state = DKG_READY; 3452 sm_trigger_run(); 3453 } 3454 3455 static void sm_handle_encryption_result_rau(void *arg){ 3456 UNUSED(arg); 3457 sm_aes128_state = SM_AES128_IDLE; 3458 3459 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3460 rau_state = RAU_IDLE; 3461 hci_le_random_address_set(sm_random_address); 3462 3463 sm_trigger_run(); 3464 } 3465 3466 static void sm_handle_random_result_rau(void * arg){ 3467 UNUSED(arg); 3468 // non-resolvable vs. resolvable 3469 switch (gap_random_adress_type){ 3470 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3471 // resolvable: use random as prand and calc address hash 3472 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3473 sm_random_address[0u] &= 0x3fu; 3474 sm_random_address[0u] |= 0x40u; 3475 rau_state = RAU_GET_ENC; 3476 break; 3477 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3478 default: 3479 // "The two most significant bits of the address shall be equal to ‘0’"" 3480 sm_random_address[0u] &= 0x3fu; 3481 rau_state = RAU_IDLE; 3482 hci_le_random_address_set(sm_random_address); 3483 break; 3484 } 3485 sm_trigger_run(); 3486 } 3487 3488 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3489 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3490 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3491 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3492 if (connection == NULL) return; 3493 3494 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3495 sm_trigger_run(); 3496 } 3497 3498 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3499 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3500 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3501 if (connection == NULL) return; 3502 3503 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3504 sm_trigger_run(); 3505 } 3506 #endif 3507 3508 static void sm_handle_random_result_ph2_random(void * arg){ 3509 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3510 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3511 if (connection == NULL) return; 3512 3513 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3514 sm_trigger_run(); 3515 } 3516 3517 static void sm_handle_random_result_ph2_tk(void * arg){ 3518 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3519 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3520 if (connection == NULL) return; 3521 3522 sm_reset_tk(); 3523 uint32_t tk; 3524 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3525 // map random to 0-999999 without speding much cycles on a modulus operation 3526 tk = little_endian_read_32(sm_random_data,0); 3527 tk = tk & 0xfffff; // 1048575 3528 if (tk >= 999999u){ 3529 tk = tk - 999999u; 3530 } 3531 } else { 3532 // override with pre-defined passkey 3533 tk = sm_fixed_passkey_in_display_role; 3534 } 3535 big_endian_store_32(setup->sm_tk, 12, tk); 3536 if (IS_RESPONDER(connection->sm_role)){ 3537 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3538 } else { 3539 if (setup->sm_use_secure_connections){ 3540 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3541 } else { 3542 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3543 sm_trigger_user_response(connection); 3544 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3545 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3546 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); 3547 } 3548 } 3549 } 3550 sm_trigger_run(); 3551 } 3552 3553 static void sm_handle_random_result_ph3_div(void * arg){ 3554 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3555 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3556 if (connection == NULL) return; 3557 3558 // use 16 bit from random value as div 3559 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3560 log_info_hex16("div", setup->sm_local_div); 3561 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3562 sm_trigger_run(); 3563 } 3564 3565 static void sm_handle_random_result_ph3_random(void * arg){ 3566 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3567 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3568 if (connection == NULL) return; 3569 3570 reverse_64(sm_random_data, setup->sm_local_rand); 3571 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3572 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3573 // no db for authenticated flag hack: store flag in bit 4 of LSB 3574 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3575 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3576 } 3577 static void sm_validate_er_ir(void){ 3578 // warn about default ER/IR 3579 bool warning = false; 3580 if (sm_ir_is_default()){ 3581 warning = true; 3582 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3583 } 3584 if (sm_er_is_default()){ 3585 warning = true; 3586 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3587 } 3588 if (warning) { 3589 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3590 } 3591 } 3592 3593 static void sm_handle_random_result_ir(void *arg){ 3594 sm_persistent_keys_random_active = false; 3595 if (arg != NULL){ 3596 // key generated, store in tlv 3597 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3598 log_info("Generated IR key. Store in TLV status: %d", status); 3599 UNUSED(status); 3600 } 3601 log_info_key("IR", sm_persistent_ir); 3602 dkg_state = DKG_CALC_IRK; 3603 3604 if (test_use_fixed_local_irk){ 3605 log_info_key("IRK", sm_persistent_irk); 3606 dkg_state = DKG_CALC_DHK; 3607 } 3608 3609 sm_trigger_run(); 3610 } 3611 3612 static void sm_handle_random_result_er(void *arg){ 3613 sm_persistent_keys_random_active = false; 3614 if (arg != 0){ 3615 // key generated, store in tlv 3616 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3617 log_info("Generated ER key. Store in TLV status: %d", status); 3618 UNUSED(status); 3619 } 3620 log_info_key("ER", sm_persistent_er); 3621 3622 // try load ir 3623 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3624 if (key_size == 16){ 3625 // ok, let's continue 3626 log_info("IR from TLV"); 3627 sm_handle_random_result_ir( NULL ); 3628 } else { 3629 // invalid, generate new random one 3630 sm_persistent_keys_random_active = true; 3631 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3632 } 3633 } 3634 3635 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){ 3636 3637 // connection info 3638 sm_conn->sm_handle = con_handle; 3639 sm_conn->sm_role = role; 3640 sm_conn->sm_peer_addr_type = addr_type; 3641 memcpy(sm_conn->sm_peer_address, address, 6); 3642 3643 // security properties 3644 sm_conn->sm_connection_encrypted = 0; 3645 sm_conn->sm_connection_authenticated = 0; 3646 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3647 sm_conn->sm_le_db_index = -1; 3648 sm_conn->sm_reencryption_active = false; 3649 3650 // prepare CSRK lookup (does not involve setup) 3651 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3652 3653 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3654 } 3655 3656 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3657 3658 UNUSED(channel); // ok: there is no channel 3659 UNUSED(size); // ok: fixed format HCI events 3660 3661 sm_connection_t * sm_conn; 3662 hci_con_handle_t con_handle; 3663 uint8_t status; 3664 bd_addr_t addr; 3665 3666 switch (packet_type) { 3667 3668 case HCI_EVENT_PACKET: 3669 switch (hci_event_packet_get_type(packet)) { 3670 3671 case BTSTACK_EVENT_STATE: 3672 switch (btstack_event_state_get_state(packet)){ 3673 case HCI_STATE_WORKING: 3674 log_info("HCI Working!"); 3675 // setup IR/ER with TLV 3676 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3677 if (sm_tlv_impl != NULL){ 3678 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3679 if (key_size == 16){ 3680 // ok, let's continue 3681 log_info("ER from TLV"); 3682 sm_handle_random_result_er( NULL ); 3683 } else { 3684 // invalid, generate random one 3685 sm_persistent_keys_random_active = true; 3686 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3687 } 3688 } else { 3689 sm_validate_er_ir(); 3690 dkg_state = DKG_CALC_IRK; 3691 3692 if (test_use_fixed_local_irk){ 3693 log_info_key("IRK", sm_persistent_irk); 3694 dkg_state = DKG_CALC_DHK; 3695 } 3696 } 3697 3698 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3699 // trigger ECC key generation 3700 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3701 sm_ec_generate_new_key(); 3702 } 3703 #endif 3704 3705 // restart random address updates after power cycle 3706 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ 3707 gap_random_address_set(sm_random_address); 3708 } else { 3709 gap_random_address_set_mode(gap_random_adress_type); 3710 } 3711 break; 3712 3713 case HCI_STATE_OFF: 3714 case HCI_STATE_HALTING: 3715 log_info("SM: reset state"); 3716 // stop random address update 3717 gap_random_address_update_stop(); 3718 // reset state 3719 sm_state_reset(); 3720 break; 3721 3722 default: 3723 break; 3724 } 3725 break; 3726 3727 #ifdef ENABLE_CLASSIC 3728 case HCI_EVENT_CONNECTION_COMPLETE: 3729 // ignore if connection failed 3730 if (hci_event_connection_complete_get_status(packet)) return; 3731 3732 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3733 sm_conn = sm_get_connection_for_handle(con_handle); 3734 if (!sm_conn) break; 3735 3736 hci_event_connection_complete_get_bd_addr(packet, addr); 3737 sm_connection_init(sm_conn, 3738 con_handle, 3739 (uint8_t) gap_get_role(con_handle), 3740 BD_ADDR_TYPE_LE_PUBLIC, 3741 addr); 3742 // classic connection corresponds to public le address 3743 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3744 gap_local_bd_addr(sm_conn->sm_own_address); 3745 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3746 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3747 break; 3748 #endif 3749 3750 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3751 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3752 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3753 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3754 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3755 if (sm_conn == NULL) break; 3756 sm_conn->sm_pairing_requested = 1; 3757 break; 3758 #endif 3759 3760 case HCI_EVENT_LE_META: 3761 switch (packet[2]) { 3762 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3763 // ignore if connection failed 3764 if (packet[3]) return; 3765 3766 con_handle = little_endian_read_16(packet, 4); 3767 sm_conn = sm_get_connection_for_handle(con_handle); 3768 if (!sm_conn) break; 3769 3770 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3771 sm_connection_init(sm_conn, 3772 con_handle, 3773 hci_subevent_le_connection_complete_get_role(packet), 3774 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3775 addr); 3776 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3777 3778 // track our addr used for this connection and set state 3779 #ifdef ENABLE_LE_PERIPHERAL 3780 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3781 // responder - use own address from advertisements 3782 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3783 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3784 } 3785 #endif 3786 #ifdef ENABLE_LE_CENTRAL 3787 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3788 // initiator - use own address from create connection 3789 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3790 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3791 } 3792 #endif 3793 break; 3794 3795 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3796 con_handle = little_endian_read_16(packet, 3); 3797 sm_conn = sm_get_connection_for_handle(con_handle); 3798 if (!sm_conn) break; 3799 3800 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3801 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3802 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3803 break; 3804 } 3805 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3806 // PH2 SEND LTK as we need to exchange keys in PH3 3807 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3808 break; 3809 } 3810 3811 // store rand and ediv 3812 reverse_64(&packet[5], sm_conn->sm_local_rand); 3813 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3814 3815 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3816 // potentially stored LTK is from the master 3817 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3818 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3819 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3820 break; 3821 } 3822 // additionally check if remote is in LE Device DB if requested 3823 switch(sm_conn->sm_irk_lookup_state){ 3824 case IRK_LOOKUP_FAILED: 3825 log_info("LTK Request: device not in device db"); 3826 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3827 break; 3828 case IRK_LOOKUP_SUCCEEDED: 3829 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3830 break; 3831 default: 3832 // wait for irk look doen 3833 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3834 break; 3835 } 3836 break; 3837 } 3838 3839 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3840 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3841 #else 3842 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3843 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3844 #endif 3845 break; 3846 3847 default: 3848 break; 3849 } 3850 break; 3851 3852 case HCI_EVENT_ENCRYPTION_CHANGE: 3853 case HCI_EVENT_ENCRYPTION_CHANGE_V2: 3854 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3855 sm_conn = sm_get_connection_for_handle(con_handle); 3856 if (!sm_conn) break; 3857 3858 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3859 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3860 sm_conn->sm_actual_encryption_key_size); 3861 log_info("event handler, state %u", sm_conn->sm_engine_state); 3862 3863 switch (sm_conn->sm_engine_state){ 3864 3865 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3866 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3867 if (sm_conn->sm_connection_encrypted) { 3868 status = ERROR_CODE_SUCCESS; 3869 if (sm_conn->sm_role){ 3870 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3871 } else { 3872 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3873 } 3874 } else { 3875 status = hci_event_encryption_change_get_status(packet); 3876 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3877 // also, gap_reconnect_security_setup_active will return true 3878 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3879 } 3880 3881 // emit re-encryption complete 3882 sm_reencryption_complete(sm_conn, status); 3883 3884 // notify client, if pairing was requested before 3885 if (sm_conn->sm_pairing_requested){ 3886 sm_conn->sm_pairing_requested = 0; 3887 sm_pairing_complete(sm_conn, status, 0); 3888 } 3889 3890 sm_done_for_handle(sm_conn->sm_handle); 3891 break; 3892 3893 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3894 if (!sm_conn->sm_connection_encrypted) break; 3895 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3896 if (IS_RESPONDER(sm_conn->sm_role)){ 3897 // slave 3898 if (setup->sm_use_secure_connections){ 3899 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3900 } else { 3901 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); 3902 } 3903 } else { 3904 // master 3905 if (sm_key_distribution_all_received()){ 3906 // skip receiving keys as there are none 3907 sm_key_distribution_handle_all_received(sm_conn); 3908 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); 3909 } else { 3910 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3911 } 3912 } 3913 break; 3914 3915 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3916 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3917 if (sm_conn->sm_connection_encrypted != 2) break; 3918 // prepare for pairing request 3919 if (IS_RESPONDER(sm_conn->sm_role)){ 3920 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3921 } else if (sm_conn->sm_pairing_requested){ 3922 // only send LE pairing request after BR/EDR SSP 3923 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3924 } 3925 break; 3926 #endif 3927 default: 3928 break; 3929 } 3930 break; 3931 3932 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3933 con_handle = little_endian_read_16(packet, 3); 3934 sm_conn = sm_get_connection_for_handle(con_handle); 3935 if (!sm_conn) break; 3936 3937 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3938 log_info("event handler, state %u", sm_conn->sm_engine_state); 3939 // continue if part of initial pairing 3940 switch (sm_conn->sm_engine_state){ 3941 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3942 if (sm_conn->sm_role){ 3943 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3944 } else { 3945 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3946 } 3947 sm_done_for_handle(sm_conn->sm_handle); 3948 break; 3949 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3950 if (IS_RESPONDER(sm_conn->sm_role)){ 3951 // slave 3952 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); 3953 } else { 3954 // master 3955 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3956 } 3957 break; 3958 default: 3959 break; 3960 } 3961 break; 3962 3963 3964 case HCI_EVENT_DISCONNECTION_COMPLETE: 3965 con_handle = little_endian_read_16(packet, 3); 3966 sm_done_for_handle(con_handle); 3967 sm_conn = sm_get_connection_for_handle(con_handle); 3968 if (!sm_conn) break; 3969 3970 // pairing failed, if it was ongoing 3971 switch (sm_conn->sm_engine_state){ 3972 case SM_GENERAL_IDLE: 3973 case SM_INITIATOR_CONNECTED: 3974 case SM_RESPONDER_IDLE: 3975 break; 3976 default: 3977 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3978 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3979 break; 3980 } 3981 3982 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3983 sm_conn->sm_handle = 0; 3984 break; 3985 3986 case HCI_EVENT_COMMAND_COMPLETE: 3987 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 3988 // set local addr for le device db 3989 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3990 le_device_db_set_local_bd_addr(addr); 3991 } 3992 break; 3993 default: 3994 break; 3995 } 3996 break; 3997 default: 3998 break; 3999 } 4000 4001 sm_run(); 4002 } 4003 4004 static inline int sm_calc_actual_encryption_key_size(int other){ 4005 if (other < sm_min_encryption_key_size) return 0; 4006 if (other < sm_max_encryption_key_size) return other; 4007 return sm_max_encryption_key_size; 4008 } 4009 4010 4011 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4012 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 4013 switch (method){ 4014 case JUST_WORKS: 4015 case NUMERIC_COMPARISON: 4016 return 1; 4017 default: 4018 return 0; 4019 } 4020 } 4021 // responder 4022 4023 static int sm_passkey_used(stk_generation_method_t method){ 4024 switch (method){ 4025 case PK_RESP_INPUT: 4026 return 1; 4027 default: 4028 return 0; 4029 } 4030 } 4031 4032 static int sm_passkey_entry(stk_generation_method_t method){ 4033 switch (method){ 4034 case PK_RESP_INPUT: 4035 case PK_INIT_INPUT: 4036 case PK_BOTH_INPUT: 4037 return 1; 4038 default: 4039 return 0; 4040 } 4041 } 4042 4043 #endif 4044 4045 /** 4046 * @return ok 4047 */ 4048 static int sm_validate_stk_generation_method(void){ 4049 // check if STK generation method is acceptable by client 4050 switch (setup->sm_stk_generation_method){ 4051 case JUST_WORKS: 4052 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4053 case PK_RESP_INPUT: 4054 case PK_INIT_INPUT: 4055 case PK_BOTH_INPUT: 4056 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4057 case OOB: 4058 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4059 case NUMERIC_COMPARISON: 4060 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4061 default: 4062 return 0; 4063 } 4064 } 4065 4066 #ifdef ENABLE_LE_CENTRAL 4067 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4068 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4069 if (sm_sc_only_mode){ 4070 uint8_t auth_req = packet[1]; 4071 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4072 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4073 return; 4074 } 4075 } 4076 #else 4077 UNUSED(packet); 4078 #endif 4079 4080 int have_ltk; 4081 uint8_t ltk[16]; 4082 4083 // IRK complete? 4084 switch (sm_conn->sm_irk_lookup_state){ 4085 case IRK_LOOKUP_FAILED: 4086 // start pairing 4087 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4088 break; 4089 case IRK_LOOKUP_SUCCEEDED: 4090 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4091 have_ltk = !sm_is_null_key(ltk); 4092 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4093 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4094 // start re-encrypt if we have LTK and the connection is not already encrypted 4095 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4096 } else { 4097 // start pairing 4098 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4099 } 4100 break; 4101 default: 4102 // otherwise, store security request 4103 sm_conn->sm_security_request_received = 1; 4104 break; 4105 } 4106 } 4107 #endif 4108 4109 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4110 4111 // size of complete sm_pdu used to validate input 4112 static const uint8_t sm_pdu_size[] = { 4113 0, // 0x00 invalid opcode 4114 7, // 0x01 pairing request 4115 7, // 0x02 pairing response 4116 17, // 0x03 pairing confirm 4117 17, // 0x04 pairing random 4118 2, // 0x05 pairing failed 4119 17, // 0x06 encryption information 4120 11, // 0x07 master identification 4121 17, // 0x08 identification information 4122 8, // 0x09 identify address information 4123 17, // 0x0a signing information 4124 2, // 0x0b security request 4125 65, // 0x0c pairing public key 4126 17, // 0x0d pairing dhk check 4127 2, // 0x0e keypress notification 4128 }; 4129 4130 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4131 sm_run(); 4132 } 4133 4134 if (packet_type != SM_DATA_PACKET) return; 4135 if (size == 0u) return; 4136 4137 uint8_t sm_pdu_code = packet[0]; 4138 4139 // validate pdu size 4140 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 4141 if (sm_pdu_size[sm_pdu_code] != size) return; 4142 4143 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4144 if (!sm_conn) return; 4145 4146 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4147 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4148 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4149 sm_done_for_handle(con_handle); 4150 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4151 return; 4152 } 4153 4154 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4155 4156 int err; 4157 UNUSED(err); 4158 4159 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4160 uint8_t buffer[5]; 4161 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4162 buffer[1] = 3; 4163 little_endian_store_16(buffer, 2, con_handle); 4164 buffer[4] = packet[1]; 4165 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4166 return; 4167 } 4168 4169 switch (sm_conn->sm_engine_state){ 4170 4171 // a sm timeout requires a new physical connection 4172 case SM_GENERAL_TIMEOUT: 4173 return; 4174 4175 #ifdef ENABLE_LE_CENTRAL 4176 4177 // Initiator 4178 case SM_INITIATOR_CONNECTED: 4179 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4180 sm_pdu_received_in_wrong_state(sm_conn); 4181 break; 4182 } 4183 sm_initiator_connected_handle_security_request(sm_conn, packet); 4184 break; 4185 4186 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4187 // Core 5, Vol 3, Part H, 2.4.6: 4188 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4189 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4190 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4191 log_info("Ignoring Security Request"); 4192 break; 4193 } 4194 4195 // all other pdus are incorrect 4196 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4197 sm_pdu_received_in_wrong_state(sm_conn); 4198 break; 4199 } 4200 4201 // store pairing request 4202 (void)memcpy(&setup->sm_s_pres, packet, 4203 sizeof(sm_pairing_packet_t)); 4204 err = sm_stk_generation_init(sm_conn); 4205 4206 #ifdef ENABLE_TESTING_SUPPORT 4207 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4208 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4209 err = test_pairing_failure; 4210 } 4211 #endif 4212 4213 if (err != 0){ 4214 sm_pairing_error(sm_conn, err); 4215 break; 4216 } 4217 4218 // generate random number first, if we need to show passkey 4219 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4220 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); 4221 break; 4222 } 4223 4224 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4225 if (setup->sm_use_secure_connections){ 4226 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4227 if (setup->sm_stk_generation_method == JUST_WORKS){ 4228 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4229 sm_trigger_user_response(sm_conn); 4230 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4231 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4232 } 4233 } else { 4234 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4235 } 4236 break; 4237 } 4238 #endif 4239 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4240 sm_trigger_user_response(sm_conn); 4241 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4242 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4243 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); 4244 } 4245 break; 4246 4247 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4248 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4249 sm_pdu_received_in_wrong_state(sm_conn); 4250 break; 4251 } 4252 4253 // store s_confirm 4254 reverse_128(&packet[1], setup->sm_peer_confirm); 4255 4256 // abort if s_confirm matches m_confirm 4257 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4258 sm_pdu_received_in_wrong_state(sm_conn); 4259 break; 4260 } 4261 4262 #ifdef ENABLE_TESTING_SUPPORT 4263 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4264 log_info("testing_support: reset confirm value"); 4265 memset(setup->sm_peer_confirm, 0, 16); 4266 } 4267 #endif 4268 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4269 break; 4270 4271 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4272 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4273 sm_pdu_received_in_wrong_state(sm_conn); 4274 break;; 4275 } 4276 4277 // received random value 4278 reverse_128(&packet[1], setup->sm_peer_random); 4279 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4280 break; 4281 #endif 4282 4283 #ifdef ENABLE_LE_PERIPHERAL 4284 // Responder 4285 case SM_RESPONDER_IDLE: 4286 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4287 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4288 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4289 sm_pdu_received_in_wrong_state(sm_conn); 4290 break;; 4291 } 4292 4293 // store pairing request 4294 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4295 4296 // check if IRK completed 4297 switch (sm_conn->sm_irk_lookup_state){ 4298 case IRK_LOOKUP_SUCCEEDED: 4299 case IRK_LOOKUP_FAILED: 4300 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4301 break; 4302 default: 4303 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4304 break; 4305 } 4306 break; 4307 #endif 4308 4309 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4310 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4311 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4312 sm_pdu_received_in_wrong_state(sm_conn); 4313 break; 4314 } 4315 4316 // store public key for DH Key calculation 4317 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4318 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4319 4320 // CVE-2020-26558: abort pairing if remote uses the same public key 4321 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4322 log_info("Remote PK matches ours"); 4323 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4324 break; 4325 } 4326 4327 // validate public key 4328 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4329 if (err != 0){ 4330 log_info("sm: peer public key invalid %x", err); 4331 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4332 break; 4333 } 4334 4335 // start calculating dhkey 4336 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); 4337 4338 4339 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4340 if (IS_RESPONDER(sm_conn->sm_role)){ 4341 // responder 4342 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4343 } else { 4344 // initiator 4345 // stk generation method 4346 // passkey entry: notify app to show passkey or to request passkey 4347 switch (setup->sm_stk_generation_method){ 4348 case JUST_WORKS: 4349 case NUMERIC_COMPARISON: 4350 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4351 break; 4352 case PK_RESP_INPUT: 4353 sm_sc_start_calculating_local_confirm(sm_conn); 4354 break; 4355 case PK_INIT_INPUT: 4356 case PK_BOTH_INPUT: 4357 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4358 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4359 break; 4360 } 4361 sm_sc_start_calculating_local_confirm(sm_conn); 4362 break; 4363 case OOB: 4364 // generate Nx 4365 log_info("Generate Na"); 4366 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); 4367 break; 4368 default: 4369 btstack_assert(false); 4370 break; 4371 } 4372 } 4373 break; 4374 4375 case SM_SC_W4_CONFIRMATION: 4376 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4377 sm_pdu_received_in_wrong_state(sm_conn); 4378 break; 4379 } 4380 // received confirm value 4381 reverse_128(&packet[1], setup->sm_peer_confirm); 4382 4383 #ifdef ENABLE_TESTING_SUPPORT 4384 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4385 log_info("testing_support: reset confirm value"); 4386 memset(setup->sm_peer_confirm, 0, 16); 4387 } 4388 #endif 4389 if (IS_RESPONDER(sm_conn->sm_role)){ 4390 // responder 4391 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4392 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4393 // still waiting for passkey 4394 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4395 break; 4396 } 4397 } 4398 sm_sc_start_calculating_local_confirm(sm_conn); 4399 } else { 4400 // initiator 4401 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4402 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); 4403 } else { 4404 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4405 } 4406 } 4407 break; 4408 4409 case SM_SC_W4_PAIRING_RANDOM: 4410 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4411 sm_pdu_received_in_wrong_state(sm_conn); 4412 break; 4413 } 4414 4415 // received random value 4416 reverse_128(&packet[1], setup->sm_peer_nonce); 4417 4418 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4419 // only check for JUST WORK/NC in initiator role OR passkey entry 4420 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4421 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4422 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4423 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4424 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4425 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4426 break; 4427 } 4428 4429 // OOB 4430 if (setup->sm_stk_generation_method == OOB){ 4431 4432 // setup local random, set to zero if remote did not receive our data 4433 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4434 if (IS_RESPONDER(sm_conn->sm_role)){ 4435 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4436 log_info("Reset rb as A does not have OOB data"); 4437 memset(setup->sm_rb, 0, 16); 4438 } else { 4439 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4440 log_info("Use stored rb"); 4441 log_info_hexdump(setup->sm_rb, 16); 4442 } 4443 } else { 4444 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4445 log_info("Reset ra as B does not have OOB data"); 4446 memset(setup->sm_ra, 0, 16); 4447 } else { 4448 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4449 log_info("Use stored ra"); 4450 log_info_hexdump(setup->sm_ra, 16); 4451 } 4452 } 4453 4454 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4455 if (setup->sm_have_oob_data){ 4456 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4457 break; 4458 } 4459 } 4460 4461 // TODO: we only get here for Responder role with JW/NC 4462 sm_sc_state_after_receiving_random(sm_conn); 4463 break; 4464 4465 case SM_SC_W2_CALCULATE_G2: 4466 case SM_SC_W4_CALCULATE_G2: 4467 case SM_SC_W4_CALCULATE_DHKEY: 4468 case SM_SC_W2_CALCULATE_F5_SALT: 4469 case SM_SC_W4_CALCULATE_F5_SALT: 4470 case SM_SC_W2_CALCULATE_F5_MACKEY: 4471 case SM_SC_W4_CALCULATE_F5_MACKEY: 4472 case SM_SC_W2_CALCULATE_F5_LTK: 4473 case SM_SC_W4_CALCULATE_F5_LTK: 4474 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4475 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4476 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4477 case SM_SC_W4_USER_RESPONSE: 4478 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4479 sm_pdu_received_in_wrong_state(sm_conn); 4480 break; 4481 } 4482 // store DHKey Check 4483 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4484 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4485 4486 // have we been only waiting for dhkey check command? 4487 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4488 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4489 } 4490 break; 4491 #endif 4492 4493 #ifdef ENABLE_LE_PERIPHERAL 4494 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4495 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4496 sm_pdu_received_in_wrong_state(sm_conn); 4497 break; 4498 } 4499 4500 // received confirm value 4501 reverse_128(&packet[1], setup->sm_peer_confirm); 4502 4503 #ifdef ENABLE_TESTING_SUPPORT 4504 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4505 log_info("testing_support: reset confirm value"); 4506 memset(setup->sm_peer_confirm, 0, 16); 4507 } 4508 #endif 4509 // notify client to hide shown passkey 4510 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4511 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4512 } 4513 4514 // handle user cancel pairing? 4515 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4516 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4517 break; 4518 } 4519 4520 // wait for user action? 4521 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4522 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4523 break; 4524 } 4525 4526 // calculate and send local_confirm 4527 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); 4528 break; 4529 4530 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4531 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4532 sm_pdu_received_in_wrong_state(sm_conn); 4533 break;; 4534 } 4535 4536 // received random value 4537 reverse_128(&packet[1], setup->sm_peer_random); 4538 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4539 break; 4540 #endif 4541 4542 case SM_PH3_RECEIVE_KEYS: 4543 switch(sm_pdu_code){ 4544 case SM_CODE_ENCRYPTION_INFORMATION: 4545 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4546 reverse_128(&packet[1], setup->sm_peer_ltk); 4547 break; 4548 4549 case SM_CODE_MASTER_IDENTIFICATION: 4550 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4551 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4552 reverse_64(&packet[3], setup->sm_peer_rand); 4553 break; 4554 4555 case SM_CODE_IDENTITY_INFORMATION: 4556 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4557 reverse_128(&packet[1], setup->sm_peer_irk); 4558 break; 4559 4560 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4561 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4562 setup->sm_peer_addr_type = packet[1]; 4563 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4564 break; 4565 4566 case SM_CODE_SIGNING_INFORMATION: 4567 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4568 reverse_128(&packet[1], setup->sm_peer_csrk); 4569 break; 4570 default: 4571 // Unexpected PDU 4572 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4573 break; 4574 } 4575 // done with key distribution? 4576 if (sm_key_distribution_all_received()){ 4577 4578 sm_key_distribution_handle_all_received(sm_conn); 4579 4580 if (IS_RESPONDER(sm_conn->sm_role)){ 4581 sm_key_distribution_complete_responder(sm_conn); 4582 } else { 4583 if (setup->sm_use_secure_connections){ 4584 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4585 } else { 4586 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); 4587 } 4588 } 4589 } 4590 break; 4591 4592 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4593 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4594 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4595 sm_pdu_received_in_wrong_state(sm_conn); 4596 break; 4597 } 4598 // store pairing response 4599 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4600 4601 // validate encryption key size 4602 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres)); 4603 // SC Only mandates 128 bit key size 4604 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4605 sm_conn->sm_actual_encryption_key_size = 0; 4606 } 4607 if (sm_conn->sm_actual_encryption_key_size == 0){ 4608 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4609 break; 4610 } 4611 4612 // prepare key exchange, LTK is derived locally 4613 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4614 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4615 4616 // skip receive if there are none 4617 if (sm_key_distribution_all_received()){ 4618 // distribute keys in run handles 'no keys to send' 4619 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4620 } else { 4621 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4622 } 4623 break; 4624 4625 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4626 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4627 sm_pdu_received_in_wrong_state(sm_conn); 4628 break; 4629 } 4630 // store pairing request 4631 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4632 // validate encryption key size 4633 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq)); 4634 // SC Only mandates 128 bit key size 4635 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4636 sm_conn->sm_actual_encryption_key_size = 0; 4637 } 4638 if (sm_conn->sm_actual_encryption_key_size == 0){ 4639 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4640 break; 4641 } 4642 // trigger response 4643 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4644 break; 4645 4646 case SM_BR_EDR_RECEIVE_KEYS: 4647 switch(sm_pdu_code){ 4648 case SM_CODE_IDENTITY_INFORMATION: 4649 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4650 reverse_128(&packet[1], setup->sm_peer_irk); 4651 break; 4652 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4653 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4654 setup->sm_peer_addr_type = packet[1]; 4655 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4656 break; 4657 case SM_CODE_SIGNING_INFORMATION: 4658 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4659 reverse_128(&packet[1], setup->sm_peer_csrk); 4660 break; 4661 default: 4662 // Unexpected PDU 4663 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4664 break; 4665 } 4666 4667 // all keys received 4668 if (sm_key_distribution_all_received()){ 4669 if (IS_RESPONDER(sm_conn->sm_role)){ 4670 // responder -> keys exchanged, derive LE LTK 4671 sm_ctkd_start_from_br_edr(sm_conn); 4672 } else { 4673 // initiator -> send our keys if any 4674 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4675 } 4676 } 4677 break; 4678 #endif 4679 4680 default: 4681 // Unexpected PDU 4682 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4683 sm_pdu_received_in_wrong_state(sm_conn); 4684 break; 4685 } 4686 4687 // try to send next pdu 4688 sm_trigger_run(); 4689 } 4690 4691 // Security Manager Client API 4692 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4693 sm_get_oob_data = get_oob_data_callback; 4694 } 4695 4696 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)){ 4697 sm_get_sc_oob_data = get_sc_oob_data_callback; 4698 } 4699 4700 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)){ 4701 sm_get_ltk_callback = get_ltk_callback; 4702 } 4703 4704 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4705 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4706 } 4707 4708 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4709 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4710 } 4711 4712 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4713 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4714 } 4715 4716 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4717 sm_min_encryption_key_size = min_size; 4718 sm_max_encryption_key_size = max_size; 4719 } 4720 4721 void sm_set_authentication_requirements(uint8_t auth_req){ 4722 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4723 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4724 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4725 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4726 } 4727 #endif 4728 sm_auth_req = auth_req; 4729 } 4730 4731 void sm_set_io_capabilities(io_capability_t io_capability){ 4732 sm_io_capabilities = io_capability; 4733 } 4734 4735 #ifdef ENABLE_LE_PERIPHERAL 4736 void sm_set_request_security(int enable){ 4737 sm_slave_request_security = enable; 4738 } 4739 #endif 4740 4741 void sm_set_er(sm_key_t er){ 4742 (void)memcpy(sm_persistent_er, er, 16); 4743 } 4744 4745 void sm_set_ir(sm_key_t ir){ 4746 (void)memcpy(sm_persistent_ir, ir, 16); 4747 } 4748 4749 // Testing support only 4750 void sm_test_set_irk(sm_key_t irk){ 4751 (void)memcpy(sm_persistent_irk, irk, 16); 4752 dkg_state = DKG_CALC_DHK; 4753 test_use_fixed_local_irk = true; 4754 } 4755 4756 void sm_test_use_fixed_local_csrk(void){ 4757 test_use_fixed_local_csrk = true; 4758 } 4759 4760 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4761 static void sm_ec_generated(void * arg){ 4762 UNUSED(arg); 4763 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4764 // trigger pairing if pending for ec key 4765 sm_trigger_run(); 4766 } 4767 static void sm_ec_generate_new_key(void){ 4768 log_info("sm: generate new ec key"); 4769 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4770 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4771 } 4772 #endif 4773 4774 #ifdef ENABLE_TESTING_SUPPORT 4775 void sm_test_set_pairing_failure(int reason){ 4776 test_pairing_failure = reason; 4777 } 4778 #endif 4779 4780 static void sm_state_reset(void) { 4781 #ifdef USE_CMAC_ENGINE 4782 sm_cmac_active = 0; 4783 #endif 4784 dkg_state = DKG_W4_WORKING; 4785 rau_state = RAU_IDLE; 4786 sm_aes128_state = SM_AES128_IDLE; 4787 sm_address_resolution_test = -1; // no private address to resolve yet 4788 sm_address_resolution_ah_calculation_active = 0; 4789 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4790 sm_address_resolution_general_queue = NULL; 4791 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4792 sm_persistent_keys_random_active = false; 4793 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4794 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4795 #endif 4796 } 4797 4798 void sm_init(void){ 4799 4800 if (sm_initialized) return; 4801 4802 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4803 sm_er_ir_set_default(); 4804 4805 // defaults 4806 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4807 | SM_STK_GENERATION_METHOD_OOB 4808 | SM_STK_GENERATION_METHOD_PASSKEY 4809 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4810 4811 sm_max_encryption_key_size = 16; 4812 sm_min_encryption_key_size = 7; 4813 4814 sm_fixed_passkey_in_display_role = 0xffffffffU; 4815 sm_reconstruct_ltk_without_le_device_db_entry = true; 4816 4817 gap_random_adress_update_period = 15 * 60 * 1000L; 4818 4819 test_use_fixed_local_csrk = false; 4820 4821 // other 4822 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4823 4824 // register for HCI Events from HCI 4825 hci_event_callback_registration.callback = &sm_event_packet_handler; 4826 hci_add_event_handler(&hci_event_callback_registration); 4827 4828 // 4829 btstack_crypto_init(); 4830 4831 // init le_device_db 4832 le_device_db_init(); 4833 4834 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4835 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4836 #ifdef ENABLE_CLASSIC 4837 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); 4838 #endif 4839 4840 // state 4841 sm_state_reset(); 4842 4843 sm_initialized = true; 4844 } 4845 4846 void sm_deinit(void){ 4847 sm_initialized = false; 4848 btstack_run_loop_remove_timer(&sm_run_timer); 4849 } 4850 4851 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4852 sm_fixed_passkey_in_display_role = passkey; 4853 } 4854 4855 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4856 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4857 } 4858 4859 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4860 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4861 if (!hci_con) return NULL; 4862 return &hci_con->sm_connection; 4863 } 4864 4865 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4866 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4867 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4868 if (!hci_con) return NULL; 4869 return &hci_con->sm_connection; 4870 } 4871 #endif 4872 4873 // @deprecated: map onto sm_request_pairing 4874 void sm_send_security_request(hci_con_handle_t con_handle){ 4875 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4876 if (!sm_conn) return; 4877 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4878 sm_request_pairing(con_handle); 4879 } 4880 4881 // request pairing 4882 void sm_request_pairing(hci_con_handle_t con_handle){ 4883 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4884 if (!sm_conn) return; // wrong connection 4885 4886 bool have_ltk; 4887 uint8_t ltk[16]; 4888 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4889 if (IS_RESPONDER(sm_conn->sm_role)){ 4890 switch (sm_conn->sm_engine_state){ 4891 case SM_GENERAL_IDLE: 4892 case SM_RESPONDER_IDLE: 4893 switch (sm_conn->sm_irk_lookup_state){ 4894 case IRK_LOOKUP_SUCCEEDED: 4895 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4896 have_ltk = !sm_is_null_key(ltk); 4897 log_info("have ltk %u", have_ltk); 4898 if (have_ltk){ 4899 sm_conn->sm_pairing_requested = 1; 4900 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4901 sm_reencryption_started(sm_conn); 4902 break; 4903 } 4904 /* fall through */ 4905 4906 case IRK_LOOKUP_FAILED: 4907 sm_conn->sm_pairing_requested = 1; 4908 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4909 sm_pairing_started(sm_conn); 4910 break; 4911 default: 4912 log_info("irk lookup pending"); 4913 sm_conn->sm_pairing_requested = 1; 4914 break; 4915 } 4916 break; 4917 default: 4918 break; 4919 } 4920 } else { 4921 // used as a trigger to start central/master/initiator security procedures 4922 switch (sm_conn->sm_engine_state){ 4923 case SM_INITIATOR_CONNECTED: 4924 switch (sm_conn->sm_irk_lookup_state){ 4925 case IRK_LOOKUP_SUCCEEDED: 4926 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4927 have_ltk = !sm_is_null_key(ltk); 4928 log_info("have ltk %u", have_ltk); 4929 if (have_ltk){ 4930 sm_conn->sm_pairing_requested = 1; 4931 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4932 break; 4933 } 4934 /* fall through */ 4935 4936 case IRK_LOOKUP_FAILED: 4937 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4938 break; 4939 default: 4940 log_info("irk lookup pending"); 4941 sm_conn->sm_pairing_requested = 1; 4942 break; 4943 } 4944 break; 4945 case SM_GENERAL_REENCRYPTION_FAILED: 4946 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4947 break; 4948 case SM_GENERAL_IDLE: 4949 sm_conn->sm_pairing_requested = 1; 4950 break; 4951 default: 4952 break; 4953 } 4954 } 4955 sm_trigger_run(); 4956 } 4957 4958 // called by client app on authorization request 4959 void sm_authorization_decline(hci_con_handle_t con_handle){ 4960 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4961 if (!sm_conn) return; // wrong connection 4962 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4963 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4964 } 4965 4966 void sm_authorization_grant(hci_con_handle_t con_handle){ 4967 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4968 if (!sm_conn) return; // wrong connection 4969 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4970 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4971 } 4972 4973 // GAP Bonding API 4974 4975 void sm_bonding_decline(hci_con_handle_t con_handle){ 4976 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4977 if (!sm_conn) return; // wrong connection 4978 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4979 log_info("decline, state %u", sm_conn->sm_engine_state); 4980 switch(sm_conn->sm_engine_state){ 4981 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4982 case SM_SC_W4_USER_RESPONSE: 4983 case SM_SC_W4_CONFIRMATION: 4984 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4985 #endif 4986 case SM_PH1_W4_USER_RESPONSE: 4987 switch (setup->sm_stk_generation_method){ 4988 case PK_RESP_INPUT: 4989 case PK_INIT_INPUT: 4990 case PK_BOTH_INPUT: 4991 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4992 break; 4993 case NUMERIC_COMPARISON: 4994 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4995 break; 4996 case JUST_WORKS: 4997 case OOB: 4998 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4999 break; 5000 default: 5001 btstack_assert(false); 5002 break; 5003 } 5004 break; 5005 default: 5006 break; 5007 } 5008 sm_trigger_run(); 5009 } 5010 5011 void sm_just_works_confirm(hci_con_handle_t con_handle){ 5012 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5013 if (!sm_conn) return; // wrong connection 5014 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 5015 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5016 if (setup->sm_use_secure_connections){ 5017 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 5018 } else { 5019 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); 5020 } 5021 } 5022 5023 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5024 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5025 sm_sc_prepare_dhkey_check(sm_conn); 5026 } 5027 #endif 5028 5029 sm_trigger_run(); 5030 } 5031 5032 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5033 // for now, it's the same 5034 sm_just_works_confirm(con_handle); 5035 } 5036 5037 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5038 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5039 if (!sm_conn) return; // wrong connection 5040 sm_reset_tk(); 5041 big_endian_store_32(setup->sm_tk, 12, passkey); 5042 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5043 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5044 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); 5045 } 5046 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5047 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5048 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5049 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5050 sm_sc_start_calculating_local_confirm(sm_conn); 5051 } 5052 #endif 5053 sm_trigger_run(); 5054 } 5055 5056 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5057 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5058 if (!sm_conn) return; // wrong connection 5059 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5060 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5061 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5062 switch (action){ 5063 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5064 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5065 flags |= (1u << action); 5066 break; 5067 case SM_KEYPRESS_PASSKEY_CLEARED: 5068 // clear counter, keypress & erased flags + set passkey cleared 5069 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5070 break; 5071 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5072 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 5073 // erase actions queued 5074 num_actions--; 5075 if (num_actions == 0u){ 5076 // clear counter, keypress & erased flags 5077 flags &= 0x19u; 5078 } 5079 break; 5080 } 5081 num_actions++; 5082 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5083 break; 5084 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5085 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5086 // enter actions queued 5087 num_actions--; 5088 if (num_actions == 0u){ 5089 // clear counter, keypress & erased flags 5090 flags &= 0x19u; 5091 } 5092 break; 5093 } 5094 num_actions++; 5095 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5096 break; 5097 default: 5098 break; 5099 } 5100 setup->sm_keypress_notification = (num_actions << 5) | flags; 5101 sm_trigger_run(); 5102 } 5103 5104 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5105 static void sm_handle_random_result_oob(void * arg){ 5106 UNUSED(arg); 5107 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5108 sm_trigger_run(); 5109 } 5110 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5111 5112 static btstack_crypto_random_t sm_crypto_random_oob_request; 5113 5114 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5115 sm_sc_oob_callback = callback; 5116 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5117 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5118 return 0; 5119 } 5120 #endif 5121 5122 /** 5123 * @brief Get Identity Resolving state 5124 * @param con_handle 5125 * @return irk_lookup_state_t 5126 */ 5127 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5128 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5129 if (!sm_conn) return IRK_LOOKUP_IDLE; 5130 return sm_conn->sm_irk_lookup_state; 5131 } 5132 5133 /** 5134 * @brief Identify device in LE Device DB 5135 * @param handle 5136 * @return index from le_device_db or -1 if not found/identified 5137 */ 5138 int sm_le_device_index(hci_con_handle_t con_handle ){ 5139 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5140 if (!sm_conn) return -1; 5141 return sm_conn->sm_le_db_index; 5142 } 5143 5144 static int gap_random_address_type_requires_updates(void){ 5145 switch (gap_random_adress_type){ 5146 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5147 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5148 return 0; 5149 default: 5150 return 1; 5151 } 5152 } 5153 5154 static uint8_t own_address_type(void){ 5155 switch (gap_random_adress_type){ 5156 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5157 return BD_ADDR_TYPE_LE_PUBLIC; 5158 default: 5159 return BD_ADDR_TYPE_LE_RANDOM; 5160 } 5161 } 5162 5163 // GAP LE API 5164 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5165 gap_random_address_update_stop(); 5166 gap_random_adress_type = random_address_type; 5167 hci_le_set_own_address_type(own_address_type()); 5168 if (!gap_random_address_type_requires_updates()) return; 5169 gap_random_address_update_start(); 5170 gap_random_address_trigger(); 5171 } 5172 5173 gap_random_address_type_t gap_random_address_get_mode(void){ 5174 return gap_random_adress_type; 5175 } 5176 5177 void gap_random_address_set_update_period(int period_ms){ 5178 gap_random_adress_update_period = period_ms; 5179 if (!gap_random_address_type_requires_updates()) return; 5180 gap_random_address_update_stop(); 5181 gap_random_address_update_start(); 5182 } 5183 5184 void gap_random_address_set(const bd_addr_t addr){ 5185 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5186 (void)memcpy(sm_random_address, addr, 6); 5187 hci_le_random_address_set(addr); 5188 } 5189 5190 #ifdef ENABLE_LE_PERIPHERAL 5191 /* 5192 * @brief Set Advertisement Paramters 5193 * @param adv_int_min 5194 * @param adv_int_max 5195 * @param adv_type 5196 * @param direct_address_type 5197 * @param direct_address 5198 * @param channel_map 5199 * @param filter_policy 5200 * 5201 * @note own_address_type is used from gap_random_address_set_mode 5202 */ 5203 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5204 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5205 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5206 direct_address_typ, direct_address, channel_map, filter_policy); 5207 } 5208 #endif 5209 5210 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5211 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5212 // wrong connection 5213 if (!sm_conn) return 0; 5214 // already encrypted 5215 if (sm_conn->sm_connection_encrypted) return 0; 5216 // irk status? 5217 switch(sm_conn->sm_irk_lookup_state){ 5218 case IRK_LOOKUP_FAILED: 5219 // done, cannot setup encryption 5220 return 0; 5221 case IRK_LOOKUP_SUCCEEDED: 5222 break; 5223 default: 5224 // IR Lookup pending 5225 return 1; 5226 } 5227 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5228 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5229 if (sm_conn->sm_role){ 5230 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5231 } else { 5232 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5233 } 5234 } 5235 5236 void sm_set_secure_connections_only_mode(bool enable){ 5237 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5238 sm_sc_only_mode = enable; 5239 #else 5240 // SC Only mode not possible without support for SC 5241 btstack_assert(enable == false); 5242 #endif 5243 } 5244 5245 const uint8_t * gap_get_persistent_irk(void){ 5246 return sm_persistent_irk; 5247 } 5248 5249 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5250 uint16_t i; 5251 for (i=0; i < le_device_db_max_count(); i++){ 5252 bd_addr_t entry_address; 5253 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5254 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5255 // skip unused entries 5256 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5257 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5258 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 5259 hci_remove_le_device_db_entry_from_resolving_list(i); 5260 #endif 5261 le_device_db_remove(i); 5262 break; 5263 } 5264 } 5265 } 5266