1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 PK_BOTH_INPUT, // Only input on both, both input PK 128 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on one (SC) or both sides (legacy) 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_DONE, 160 } ec_key_generation_state_t; 161 162 typedef enum { 163 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 164 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 165 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 166 } sm_state_var_t; 167 168 typedef enum { 169 SM_SC_OOB_IDLE, 170 SM_SC_OOB_W4_RANDOM, 171 SM_SC_OOB_W2_CALC_CONFIRM, 172 SM_SC_OOB_W4_CONFIRM, 173 } sm_sc_oob_state_t; 174 175 typedef uint8_t sm_key24_t[3]; 176 typedef uint8_t sm_key56_t[7]; 177 typedef uint8_t sm_key256_t[32]; 178 179 // 180 // GLOBAL DATA 181 // 182 183 static bool sm_initialized; 184 185 static bool test_use_fixed_local_csrk; 186 static bool test_use_fixed_local_irk; 187 188 #ifdef ENABLE_TESTING_SUPPORT 189 static uint8_t test_pairing_failure; 190 #endif 191 192 // configuration 193 static uint8_t sm_accepted_stk_generation_methods; 194 static uint8_t sm_max_encryption_key_size; 195 static uint8_t sm_min_encryption_key_size; 196 static uint8_t sm_auth_req = 0; 197 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 198 static uint8_t sm_slave_request_security; 199 static uint32_t sm_fixed_passkey_in_display_role; 200 static bool sm_reconstruct_ltk_without_le_device_db_entry; 201 202 #ifdef ENABLE_LE_SECURE_CONNECTIONS 203 static bool sm_sc_only_mode; 204 static uint8_t sm_sc_oob_random[16]; 205 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 206 static sm_sc_oob_state_t sm_sc_oob_state; 207 #endif 208 209 210 static bool sm_persistent_keys_random_active; 211 static const btstack_tlv_t * sm_tlv_impl; 212 static void * sm_tlv_context; 213 214 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 215 static sm_key_t sm_persistent_er; 216 static sm_key_t sm_persistent_ir; 217 218 // derived from sm_persistent_ir 219 static sm_key_t sm_persistent_dhk; 220 static sm_key_t sm_persistent_irk; 221 static derived_key_generation_t dkg_state; 222 223 // derived from sm_persistent_er 224 // .. 225 226 // random address update 227 static random_address_update_t rau_state; 228 static bd_addr_t sm_random_address; 229 230 #ifdef USE_CMAC_ENGINE 231 // CMAC Calculation: General 232 static btstack_crypto_aes128_cmac_t sm_cmac_request; 233 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 234 static uint8_t sm_cmac_active; 235 static uint8_t sm_cmac_hash[16]; 236 #endif 237 238 // CMAC for ATT Signed Writes 239 #ifdef ENABLE_LE_SIGNED_WRITE 240 static uint16_t sm_cmac_signed_write_message_len; 241 static uint8_t sm_cmac_signed_write_header[3]; 242 static const uint8_t * sm_cmac_signed_write_message; 243 static uint8_t sm_cmac_signed_write_sign_counter[4]; 244 #endif 245 246 // CMAC for Secure Connection functions 247 #ifdef ENABLE_LE_SECURE_CONNECTIONS 248 static sm_connection_t * sm_cmac_connection; 249 static uint8_t sm_cmac_sc_buffer[80]; 250 #endif 251 252 // resolvable private address lookup / CSRK calculation 253 static int sm_address_resolution_test; 254 static int sm_address_resolution_ah_calculation_active; 255 static uint8_t sm_address_resolution_addr_type; 256 static bd_addr_t sm_address_resolution_address; 257 static void * sm_address_resolution_context; 258 static address_resolution_mode_t sm_address_resolution_mode; 259 static btstack_linked_list_t sm_address_resolution_general_queue; 260 261 // aes128 crypto engine. 262 static sm_aes128_state_t sm_aes128_state; 263 264 // crypto 265 static btstack_crypto_random_t sm_crypto_random_request; 266 static btstack_crypto_aes128_t sm_crypto_aes128_request; 267 #ifdef ENABLE_LE_SECURE_CONNECTIONS 268 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 269 #endif 270 271 // temp storage for random data 272 static uint8_t sm_random_data[8]; 273 static uint8_t sm_aes128_key[16]; 274 static uint8_t sm_aes128_plaintext[16]; 275 static uint8_t sm_aes128_ciphertext[16]; 276 277 // to receive hci events 278 static btstack_packet_callback_registration_t hci_event_callback_registration; 279 280 /* to dispatch sm event */ 281 static btstack_linked_list_t sm_event_handlers; 282 283 /* to schedule calls to sm_run */ 284 static btstack_timer_source_t sm_run_timer; 285 286 // LE Secure Connections 287 #ifdef ENABLE_LE_SECURE_CONNECTIONS 288 static ec_key_generation_state_t ec_key_generation_state; 289 static uint8_t ec_q[64]; 290 #endif 291 292 // 293 // Volume 3, Part H, Chapter 24 294 // "Security shall be initiated by the Security Manager in the device in the master role. 295 // The device in the slave role shall be the responding device." 296 // -> master := initiator, slave := responder 297 // 298 299 // data needed for security setup 300 typedef struct sm_setup_context { 301 302 btstack_timer_source_t sm_timeout; 303 304 // user response, (Phase 1 and/or 2) 305 uint8_t sm_user_response; 306 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 307 308 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 309 uint8_t sm_key_distribution_send_set; 310 uint8_t sm_key_distribution_sent_set; 311 uint8_t sm_key_distribution_expected_set; 312 uint8_t sm_key_distribution_received_set; 313 314 // Phase 2 (Pairing over SMP) 315 stk_generation_method_t sm_stk_generation_method; 316 sm_key_t sm_tk; 317 uint8_t sm_have_oob_data; 318 uint8_t sm_use_secure_connections; 319 320 sm_key_t sm_c1_t3_value; // c1 calculation 321 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 322 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 323 sm_key_t sm_local_random; 324 sm_key_t sm_local_confirm; 325 sm_key_t sm_peer_random; 326 sm_key_t sm_peer_confirm; 327 uint8_t sm_m_addr_type; // address and type can be removed 328 uint8_t sm_s_addr_type; // '' 329 bd_addr_t sm_m_address; // '' 330 bd_addr_t sm_s_address; // '' 331 sm_key_t sm_ltk; 332 333 uint8_t sm_state_vars; 334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 335 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 336 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 337 sm_key_t sm_local_nonce; // might be combined with sm_local_random 338 uint8_t sm_dhkey[32]; 339 sm_key_t sm_peer_dhkey_check; 340 sm_key_t sm_local_dhkey_check; 341 sm_key_t sm_ra; 342 sm_key_t sm_rb; 343 sm_key_t sm_t; // used for f5 and h6 344 sm_key_t sm_mackey; 345 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 346 #endif 347 348 // Phase 3 349 350 // key distribution, we generate 351 uint16_t sm_local_y; 352 uint16_t sm_local_div; 353 uint16_t sm_local_ediv; 354 uint8_t sm_local_rand[8]; 355 sm_key_t sm_local_ltk; 356 sm_key_t sm_local_csrk; 357 sm_key_t sm_local_irk; 358 // sm_local_address/addr_type not needed 359 360 // key distribution, received from peer 361 uint16_t sm_peer_y; 362 uint16_t sm_peer_div; 363 uint16_t sm_peer_ediv; 364 uint8_t sm_peer_rand[8]; 365 sm_key_t sm_peer_ltk; 366 sm_key_t sm_peer_irk; 367 sm_key_t sm_peer_csrk; 368 uint8_t sm_peer_addr_type; 369 bd_addr_t sm_peer_address; 370 #ifdef ENABLE_LE_SIGNED_WRITE 371 int sm_le_device_index; 372 #endif 373 } sm_setup_context_t; 374 375 // 376 static sm_setup_context_t the_setup; 377 static sm_setup_context_t * setup = &the_setup; 378 379 // active connection - the one for which the_setup is used for 380 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 381 382 // @returns 1 if oob data is available 383 // stores oob data in provided 16 byte buffer if not null 384 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 385 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); 386 387 static void sm_run(void); 388 static void sm_done_for_handle(hci_con_handle_t con_handle); 389 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 390 static inline int sm_calc_actual_encryption_key_size(int other); 391 static int sm_validate_stk_generation_method(void); 392 static void sm_handle_encryption_result_address_resolution(void *arg); 393 static void sm_handle_encryption_result_dkg_dhk(void *arg); 394 static void sm_handle_encryption_result_dkg_irk(void *arg); 395 static void sm_handle_encryption_result_enc_a(void *arg); 396 static void sm_handle_encryption_result_enc_b(void *arg); 397 static void sm_handle_encryption_result_enc_c(void *arg); 398 static void sm_handle_encryption_result_enc_csrk(void *arg); 399 static void sm_handle_encryption_result_enc_d(void * arg); 400 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 401 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 402 #ifdef ENABLE_LE_PERIPHERAL 403 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 404 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 405 #endif 406 static void sm_handle_encryption_result_enc_stk(void *arg); 407 static void sm_handle_encryption_result_rau(void *arg); 408 static void sm_handle_random_result_ph2_tk(void * arg); 409 static void sm_handle_random_result_rau(void * arg); 410 #ifdef ENABLE_LE_SECURE_CONNECTIONS 411 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)); 412 static void sm_ec_generate_new_key(void); 413 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 414 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 415 static int sm_passkey_entry(stk_generation_method_t method); 416 #endif 417 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 418 419 static void log_info_hex16(const char * name, uint16_t value){ 420 log_info("%-6s 0x%04x", name, value); 421 } 422 423 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 424 // return packet[0]; 425 // } 426 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 427 return packet[1]; 428 } 429 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 430 return packet[2]; 431 } 432 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 433 return packet[3]; 434 } 435 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 436 return packet[4]; 437 } 438 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 439 return packet[5]; 440 } 441 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 442 return packet[6]; 443 } 444 445 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 446 packet[0] = code; 447 } 448 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 449 packet[1] = io_capability; 450 } 451 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 452 packet[2] = oob_data_flag; 453 } 454 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 455 packet[3] = auth_req; 456 } 457 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 458 packet[4] = max_encryption_key_size; 459 } 460 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 461 packet[5] = initiator_key_distribution; 462 } 463 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 464 packet[6] = responder_key_distribution; 465 } 466 467 // @returns 1 if all bytes are 0 468 static bool sm_is_null(uint8_t * data, int size){ 469 int i; 470 for (i=0; i < size ; i++){ 471 if (data[i] != 0) { 472 return false; 473 } 474 } 475 return true; 476 } 477 478 static bool sm_is_null_random(uint8_t random[8]){ 479 return sm_is_null(random, 8); 480 } 481 482 static bool sm_is_null_key(uint8_t * key){ 483 return sm_is_null(key, 16); 484 } 485 486 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 487 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 488 UNUSED(ts); 489 sm_run(); 490 } 491 static void sm_trigger_run(void){ 492 if (!sm_initialized) return; 493 (void)btstack_run_loop_remove_timer(&sm_run_timer); 494 btstack_run_loop_set_timer(&sm_run_timer, 0); 495 btstack_run_loop_add_timer(&sm_run_timer); 496 } 497 498 // Key utils 499 static void sm_reset_tk(void){ 500 int i; 501 for (i=0;i<16;i++){ 502 setup->sm_tk[i] = 0; 503 } 504 } 505 506 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 507 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 508 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 509 int i; 510 for (i = max_encryption_size ; i < 16 ; i++){ 511 key[15-i] = 0; 512 } 513 } 514 515 // ER / IR checks 516 static void sm_er_ir_set_default(void){ 517 int i; 518 for (i=0;i<16;i++){ 519 sm_persistent_er[i] = 0x30 + i; 520 sm_persistent_ir[i] = 0x90 + i; 521 } 522 } 523 524 static int sm_er_is_default(void){ 525 int i; 526 for (i=0;i<16;i++){ 527 if (sm_persistent_er[i] != (0x30+i)) return 0; 528 } 529 return 1; 530 } 531 532 static int sm_ir_is_default(void){ 533 int i; 534 for (i=0;i<16;i++){ 535 if (sm_persistent_ir[i] != (0x90+i)) return 0; 536 } 537 return 1; 538 } 539 540 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 541 UNUSED(channel); 542 543 // log event 544 hci_dump_packet(packet_type, 1, packet, size); 545 // dispatch to all event handlers 546 btstack_linked_list_iterator_t it; 547 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 548 while (btstack_linked_list_iterator_has_next(&it)){ 549 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 550 entry->callback(packet_type, 0, packet, size); 551 } 552 } 553 554 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){ 555 event[0] = type; 556 event[1] = event_size - 2; 557 little_endian_store_16(event, 2, con_handle); 558 event[4] = addr_type; 559 reverse_bd_addr(address, &event[5]); 560 } 561 562 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 563 uint8_t event[11]; 564 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 565 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 566 } 567 568 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 569 uint8_t event[15]; 570 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 571 little_endian_store_32(event, 11, passkey); 572 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 573 } 574 575 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){ 576 // fetch addr and addr type from db, only called for valid entries 577 bd_addr_t identity_address; 578 int identity_address_type; 579 le_device_db_info(index, &identity_address_type, identity_address, NULL); 580 581 uint8_t event[20]; 582 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 583 event[11] = identity_address_type; 584 reverse_bd_addr(identity_address, &event[12]); 585 little_endian_store_16(event, 18, index); 586 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 587 } 588 589 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){ 590 uint8_t event[12]; 591 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 592 event[11] = status; 593 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 594 } 595 596 597 static void sm_reencryption_started(sm_connection_t * sm_conn){ 598 599 if (sm_conn->sm_reencryption_active) return; 600 601 sm_conn->sm_reencryption_active = true; 602 603 int identity_addr_type; 604 bd_addr_t identity_addr; 605 if (sm_conn->sm_le_db_index >= 0){ 606 // fetch addr and addr type from db, only called for valid entries 607 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 608 } else { 609 // for legacy pairing with LTK re-construction, use current peer addr 610 identity_addr_type = sm_conn->sm_peer_addr_type; 611 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 612 } 613 614 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 615 } 616 617 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 618 619 if (!sm_conn->sm_reencryption_active) return; 620 621 sm_conn->sm_reencryption_active = false; 622 623 int identity_addr_type; 624 bd_addr_t identity_addr; 625 if (sm_conn->sm_le_db_index >= 0){ 626 // fetch addr and addr type from db, only called for valid entries 627 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 628 } else { 629 // for legacy pairing with LTK re-construction, use current peer addr 630 identity_addr_type = sm_conn->sm_peer_addr_type; 631 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 632 } 633 634 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 635 } 636 637 static void sm_pairing_started(sm_connection_t * sm_conn){ 638 639 if (sm_conn->sm_pairing_active) return; 640 641 sm_conn->sm_pairing_active = true; 642 643 uint8_t event[11]; 644 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 645 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 646 } 647 648 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 649 650 if (!sm_conn->sm_pairing_active) return; 651 652 sm_conn->sm_pairing_active = false; 653 654 uint8_t event[13]; 655 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 656 event[11] = status; 657 event[12] = reason; 658 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 659 } 660 661 // SMP Timeout implementation 662 663 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 664 // the Security Manager Timer shall be reset and started. 665 // 666 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 667 // 668 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 669 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 670 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 671 // established. 672 673 static void sm_timeout_handler(btstack_timer_source_t * timer){ 674 log_info("SM timeout"); 675 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 676 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 677 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 678 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 679 sm_done_for_handle(sm_conn->sm_handle); 680 681 // trigger handling of next ready connection 682 sm_run(); 683 } 684 static void sm_timeout_start(sm_connection_t * sm_conn){ 685 btstack_run_loop_remove_timer(&setup->sm_timeout); 686 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 687 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 688 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 689 btstack_run_loop_add_timer(&setup->sm_timeout); 690 } 691 static void sm_timeout_stop(void){ 692 btstack_run_loop_remove_timer(&setup->sm_timeout); 693 } 694 static void sm_timeout_reset(sm_connection_t * sm_conn){ 695 sm_timeout_stop(); 696 sm_timeout_start(sm_conn); 697 } 698 699 // end of sm timeout 700 701 // GAP Random Address updates 702 static gap_random_address_type_t gap_random_adress_type; 703 static btstack_timer_source_t gap_random_address_update_timer; 704 static uint32_t gap_random_adress_update_period; 705 706 static void gap_random_address_trigger(void){ 707 log_info("gap_random_address_trigger, state %u", rau_state); 708 if (rau_state != RAU_IDLE) return; 709 rau_state = RAU_GET_RANDOM; 710 sm_trigger_run(); 711 } 712 713 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 714 UNUSED(timer); 715 716 log_info("GAP Random Address Update due"); 717 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 718 btstack_run_loop_add_timer(&gap_random_address_update_timer); 719 gap_random_address_trigger(); 720 } 721 722 static void gap_random_address_update_start(void){ 723 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 724 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 725 btstack_run_loop_add_timer(&gap_random_address_update_timer); 726 } 727 728 static void gap_random_address_update_stop(void){ 729 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 730 } 731 732 // ah(k,r) helper 733 // r = padding || r 734 // r - 24 bit value 735 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 736 // r'= padding || r 737 memset(r_prime, 0, 16); 738 (void)memcpy(&r_prime[13], r, 3); 739 } 740 741 // d1 helper 742 // d' = padding || r || d 743 // d,r - 16 bit values 744 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 745 // d'= padding || r || d 746 memset(d1_prime, 0, 16); 747 big_endian_store_16(d1_prime, 12, r); 748 big_endian_store_16(d1_prime, 14, d); 749 } 750 751 // calculate arguments for first AES128 operation in C1 function 752 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){ 753 754 // p1 = pres || preq || rat’ || iat’ 755 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 756 // cant octet of pres becomes the most significant octet of p1. 757 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 758 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 759 // p1 is 0x05000800000302070710000001010001." 760 761 sm_key_t p1; 762 reverse_56(pres, &p1[0]); 763 reverse_56(preq, &p1[7]); 764 p1[14] = rat; 765 p1[15] = iat; 766 log_info_key("p1", p1); 767 log_info_key("r", r); 768 769 // t1 = r xor p1 770 int i; 771 for (i=0;i<16;i++){ 772 t1[i] = r[i] ^ p1[i]; 773 } 774 log_info_key("t1", t1); 775 } 776 777 // calculate arguments for second AES128 operation in C1 function 778 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 779 // p2 = padding || ia || ra 780 // "The least significant octet of ra becomes the least significant octet of p2 and 781 // the most significant octet of padding becomes the most significant octet of p2. 782 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 783 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 784 785 sm_key_t p2; 786 memset(p2, 0, 16); 787 (void)memcpy(&p2[4], ia, 6); 788 (void)memcpy(&p2[10], ra, 6); 789 log_info_key("p2", p2); 790 791 // c1 = e(k, t2_xor_p2) 792 int i; 793 for (i=0;i<16;i++){ 794 t3[i] = t2[i] ^ p2[i]; 795 } 796 log_info_key("t3", t3); 797 } 798 799 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 800 log_info_key("r1", r1); 801 log_info_key("r2", r2); 802 (void)memcpy(&r_prime[8], &r2[8], 8); 803 (void)memcpy(&r_prime[0], &r1[8], 8); 804 } 805 806 807 // decide on stk generation based on 808 // - pairing request 809 // - io capabilities 810 // - OOB data availability 811 static void sm_setup_tk(void){ 812 813 // horizontal: initiator capabilities 814 // vertial: responder capabilities 815 static const stk_generation_method_t stk_generation_method [5] [5] = { 816 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 817 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 818 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 819 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 820 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 821 }; 822 823 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 824 #ifdef ENABLE_LE_SECURE_CONNECTIONS 825 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 826 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 827 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 828 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 829 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 830 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 831 }; 832 #endif 833 834 // default: just works 835 setup->sm_stk_generation_method = JUST_WORKS; 836 837 #ifdef ENABLE_LE_SECURE_CONNECTIONS 838 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 839 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 840 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 841 #else 842 setup->sm_use_secure_connections = 0; 843 #endif 844 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 845 846 847 // decide if OOB will be used based on SC vs. Legacy and oob flags 848 bool use_oob; 849 if (setup->sm_use_secure_connections){ 850 // In LE Secure Connections pairing, the out of band method is used if at least 851 // one device has the peer device's out of band authentication data available. 852 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; 853 } else { 854 // In LE legacy pairing, the out of band method is used if both the devices have 855 // the other 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 } 858 if (use_oob){ 859 log_info("SM: have OOB data"); 860 log_info_key("OOB", setup->sm_tk); 861 setup->sm_stk_generation_method = OOB; 862 return; 863 } 864 865 // If both devices have not set the MITM option in the Authentication Requirements 866 // Flags, then the IO capabilities shall be ignored and the Just Works association 867 // model shall be used. 868 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 869 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 870 log_info("SM: MITM not required by both -> JUST WORKS"); 871 return; 872 } 873 874 // Reset TK as it has been setup in sm_init_setup 875 sm_reset_tk(); 876 877 // Also use just works if unknown io capabilites 878 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)){ 879 return; 880 } 881 882 // Otherwise the IO capabilities of the devices shall be used to determine the 883 // pairing method as defined in Table 2.4. 884 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 885 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 886 887 #ifdef ENABLE_LE_SECURE_CONNECTIONS 888 // table not define by default 889 if (setup->sm_use_secure_connections){ 890 generation_method = stk_generation_method_with_secure_connection; 891 } 892 #endif 893 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)]; 894 895 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 896 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); 897 } 898 899 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 900 int flags = 0; 901 if (key_set & SM_KEYDIST_ENC_KEY){ 902 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 903 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 904 } 905 if (key_set & SM_KEYDIST_ID_KEY){ 906 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 907 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 908 } 909 if (key_set & SM_KEYDIST_SIGN){ 910 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 911 } 912 return flags; 913 } 914 915 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 916 setup->sm_key_distribution_received_set = 0; 917 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 918 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 919 setup->sm_key_distribution_sent_set = 0; 920 #ifdef ENABLE_LE_SIGNED_WRITE 921 setup->sm_le_device_index = -1; 922 #endif 923 } 924 925 // CSRK Key Lookup 926 927 928 static int sm_address_resolution_idle(void){ 929 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 930 } 931 932 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){ 933 (void)memcpy(sm_address_resolution_address, addr, 6); 934 sm_address_resolution_addr_type = addr_type; 935 sm_address_resolution_test = 0; 936 sm_address_resolution_mode = mode; 937 sm_address_resolution_context = context; 938 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 939 } 940 941 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 942 // check if already in list 943 btstack_linked_list_iterator_t it; 944 sm_lookup_entry_t * entry; 945 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 946 while(btstack_linked_list_iterator_has_next(&it)){ 947 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 948 if (entry->address_type != address_type) continue; 949 if (memcmp(entry->address, address, 6)) continue; 950 // already in list 951 return BTSTACK_BUSY; 952 } 953 entry = btstack_memory_sm_lookup_entry_get(); 954 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 955 entry->address_type = (bd_addr_type_t) address_type; 956 (void)memcpy(entry->address, address, 6); 957 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 958 sm_trigger_run(); 959 return 0; 960 } 961 962 // CMAC calculation using AES Engineq 963 #ifdef USE_CMAC_ENGINE 964 965 static void sm_cmac_done_trampoline(void * arg){ 966 UNUSED(arg); 967 sm_cmac_active = 0; 968 (*sm_cmac_done_callback)(sm_cmac_hash); 969 sm_trigger_run(); 970 } 971 972 int sm_cmac_ready(void){ 973 return sm_cmac_active == 0u; 974 } 975 #endif 976 977 #ifdef ENABLE_LE_SECURE_CONNECTIONS 978 // generic cmac calculation 979 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)){ 980 sm_cmac_active = 1; 981 sm_cmac_done_callback = done_callback; 982 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 983 } 984 #endif 985 986 // cmac for ATT Message signing 987 #ifdef ENABLE_LE_SIGNED_WRITE 988 989 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)){ 990 sm_cmac_active = 1; 991 sm_cmac_done_callback = done_callback; 992 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 993 } 994 995 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 996 if (offset >= sm_cmac_signed_write_message_len) { 997 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 998 return 0; 999 } 1000 1001 offset = sm_cmac_signed_write_message_len - 1 - offset; 1002 1003 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1004 if (offset < 3){ 1005 return sm_cmac_signed_write_header[offset]; 1006 } 1007 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1008 if (offset < actual_message_len_incl_header){ 1009 return sm_cmac_signed_write_message[offset - 3]; 1010 } 1011 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1012 } 1013 1014 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)){ 1015 // ATT Message Signing 1016 sm_cmac_signed_write_header[0] = opcode; 1017 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1018 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1019 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1020 sm_cmac_signed_write_message = message; 1021 sm_cmac_signed_write_message_len = total_message_len; 1022 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1023 } 1024 #endif 1025 1026 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1027 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1028 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1029 sm_conn->sm_pairing_active = true; 1030 switch (setup->sm_stk_generation_method){ 1031 case PK_RESP_INPUT: 1032 if (IS_RESPONDER(sm_conn->sm_role)){ 1033 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1034 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1035 } else { 1036 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1037 } 1038 break; 1039 case PK_INIT_INPUT: 1040 if (IS_RESPONDER(sm_conn->sm_role)){ 1041 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1042 } else { 1043 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1044 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1045 } 1046 break; 1047 case PK_BOTH_INPUT: 1048 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1049 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1050 break; 1051 case NUMERIC_COMPARISON: 1052 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1053 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1054 break; 1055 case JUST_WORKS: 1056 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1057 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1058 break; 1059 case OOB: 1060 // client already provided OOB data, let's skip notification. 1061 break; 1062 default: 1063 btstack_assert(false); 1064 break; 1065 } 1066 } 1067 1068 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1069 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, bution_expected_set); 1070 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1071 } 1072 1073 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1074 if (sm_active_connection_handle == con_handle){ 1075 sm_timeout_stop(); 1076 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1077 log_info("sm: connection 0x%x released setup context", con_handle); 1078 1079 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1080 // generate new ec key after each pairing (that used it) 1081 if (setup->sm_use_secure_connections){ 1082 sm_ec_generate_new_key(); 1083 } 1084 #endif 1085 } 1086 } 1087 1088 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1089 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1090 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1091 sm_done_for_handle(connection->sm_handle); 1092 } 1093 1094 static int sm_key_distribution_flags_for_auth_req(void){ 1095 1096 int flags = SM_KEYDIST_ID_KEY; 1097 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1098 // encryption and signing information only if bonding requested 1099 flags |= SM_KEYDIST_ENC_KEY; 1100 #ifdef ENABLE_LE_SIGNED_WRITE 1101 flags |= SM_KEYDIST_SIGN; 1102 #endif 1103 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1104 // LinkKey for CTKD requires SC 1105 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1106 flags |= SM_KEYDIST_LINK_KEY; 1107 } 1108 #endif 1109 } 1110 return flags; 1111 } 1112 1113 static void sm_reset_setup(void){ 1114 // fill in sm setup 1115 setup->sm_state_vars = 0; 1116 setup->sm_keypress_notification = 0; 1117 sm_reset_tk(); 1118 } 1119 1120 static void sm_init_setup(sm_connection_t * sm_conn){ 1121 1122 // fill in sm setup 1123 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1124 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1125 1126 // query client for Legacy Pairing OOB data 1127 setup->sm_have_oob_data = 0; 1128 if (sm_get_oob_data != NULL) { 1129 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1130 } 1131 1132 // if available and SC supported, also ask for SC OOB Data 1133 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1134 memset(setup->sm_ra, 0, 16); 1135 memset(setup->sm_rb, 0, 16); 1136 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1137 if (sm_get_sc_oob_data != NULL){ 1138 if (IS_RESPONDER(sm_conn->sm_role)){ 1139 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1140 sm_conn->sm_peer_addr_type, 1141 sm_conn->sm_peer_address, 1142 setup->sm_peer_confirm, 1143 setup->sm_ra); 1144 } else { 1145 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1146 sm_conn->sm_peer_addr_type, 1147 sm_conn->sm_peer_address, 1148 setup->sm_peer_confirm, 1149 setup->sm_rb); 1150 } 1151 } else { 1152 setup->sm_have_oob_data = 0; 1153 } 1154 } 1155 #endif 1156 1157 sm_pairing_packet_t * local_packet; 1158 if (IS_RESPONDER(sm_conn->sm_role)){ 1159 // slave 1160 local_packet = &setup->sm_s_pres; 1161 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1162 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1163 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1164 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1165 } else { 1166 // master 1167 local_packet = &setup->sm_m_preq; 1168 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1169 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1170 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1171 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1172 1173 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1174 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1175 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1176 } 1177 1178 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1179 uint8_t max_encryptinon_key_size = sm_max_encryption_key_size; 1180 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1181 // enable SC for SC only mode 1182 if (sm_sc_only_mode){ 1183 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1184 max_encryptinon_key_size = 16; 1185 } 1186 #endif 1187 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1188 // set CT2 if SC + Bonding + CTKD 1189 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1190 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1191 auth_req |= SM_AUTHREQ_CT2; 1192 } 1193 #endif 1194 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1195 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1196 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1197 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryptinon_key_size); 1198 } 1199 1200 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1201 1202 sm_pairing_packet_t * remote_packet; 1203 uint8_t keys_to_send; 1204 uint8_t keys_to_receive; 1205 if (IS_RESPONDER(sm_conn->sm_role)){ 1206 // slave / responder 1207 remote_packet = &setup->sm_m_preq; 1208 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1209 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1210 } else { 1211 // master / initiator 1212 remote_packet = &setup->sm_s_pres; 1213 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1214 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1215 } 1216 1217 // check key size 1218 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1219 // SC Only mandates 128 bit key size 1220 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1221 return SM_REASON_ENCRYPTION_KEY_SIZE; 1222 } 1223 #endif 1224 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1225 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1226 1227 // decide on STK generation method / SC 1228 sm_setup_tk(); 1229 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1230 1231 // check if STK generation method is acceptable by client 1232 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1233 1234 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1235 // Check LE SC Only mode 1236 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1237 log_info("SC Only mode active but SC not possible"); 1238 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1239 } 1240 1241 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1242 if (setup->sm_use_secure_connections){ 1243 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1244 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1245 } 1246 #endif 1247 1248 // identical to responder 1249 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1250 1251 // JUST WORKS doens't provide authentication 1252 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1253 1254 return 0; 1255 } 1256 1257 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1258 1259 // cache and reset context 1260 int matched_device_id = sm_address_resolution_test; 1261 address_resolution_mode_t mode = sm_address_resolution_mode; 1262 void * context = sm_address_resolution_context; 1263 1264 // reset context 1265 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1266 sm_address_resolution_context = NULL; 1267 sm_address_resolution_test = -1; 1268 hci_con_handle_t con_handle = 0; 1269 1270 sm_connection_t * sm_connection; 1271 sm_key_t ltk; 1272 bool have_ltk; 1273 #ifdef ENABLE_LE_CENTRAL 1274 bool trigger_pairing; 1275 #endif 1276 switch (mode){ 1277 case ADDRESS_RESOLUTION_GENERAL: 1278 break; 1279 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1280 sm_connection = (sm_connection_t *) context; 1281 con_handle = sm_connection->sm_handle; 1282 1283 // have ltk -> start encryption / send security request 1284 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1285 // "When a bond has been created between two devices, any reconnection should result in the local device 1286 // enabling or requesting encryption with the remote device before initiating any service request." 1287 1288 switch (event){ 1289 case ADDRESS_RESOLUTION_SUCCEEDED: 1290 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1291 sm_connection->sm_le_db_index = matched_device_id; 1292 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1293 1294 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1295 have_ltk = !sm_is_null_key(ltk); 1296 1297 if (sm_connection->sm_role) { 1298 #ifdef ENABLE_LE_PERIPHERAL 1299 // IRK required before, continue 1300 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1301 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1302 break; 1303 } 1304 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1305 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1306 break; 1307 } 1308 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1309 sm_connection->sm_pairing_requested = 0; 1310 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1311 // trigger security request for Proactive Authentication if LTK available 1312 trigger_security_request = trigger_security_request || have_ltk; 1313 #endif 1314 1315 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1316 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1317 1318 if (trigger_security_request){ 1319 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1320 if (have_ltk){ 1321 sm_reencryption_started(sm_connection); 1322 } else { 1323 sm_pairing_started(sm_connection); 1324 } 1325 sm_trigger_run(); 1326 } 1327 #endif 1328 } else { 1329 1330 #ifdef ENABLE_LE_CENTRAL 1331 // check if pairing already requested and reset requests 1332 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1333 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1334 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1335 sm_connection->sm_security_request_received = 0; 1336 sm_connection->sm_pairing_requested = 0; 1337 bool trigger_reencryption = false; 1338 1339 if (have_ltk){ 1340 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1341 trigger_reencryption = true; 1342 #else 1343 if (trigger_pairing){ 1344 trigger_reencryption = true; 1345 } else { 1346 log_info("central: defer enabling encryption for bonded device"); 1347 } 1348 #endif 1349 } 1350 1351 if (trigger_reencryption){ 1352 log_info("central: enable encryption for bonded device"); 1353 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1354 break; 1355 } 1356 1357 // pairing_request -> send pairing request 1358 if (trigger_pairing){ 1359 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1360 break; 1361 } 1362 #endif 1363 } 1364 break; 1365 case ADDRESS_RESOLUTION_FAILED: 1366 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1367 if (sm_connection->sm_role) { 1368 #ifdef ENABLE_LE_PERIPHERAL 1369 // LTK request received before, IRK required -> negative LTK reply 1370 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1371 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1372 } 1373 // send security request if requested 1374 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1375 sm_connection->sm_pairing_requested = 0; 1376 if (trigger_security_request){ 1377 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1378 sm_pairing_started(sm_connection); 1379 } 1380 break; 1381 #endif 1382 } 1383 #ifdef ENABLE_LE_CENTRAL 1384 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1385 sm_connection->sm_security_request_received = 0; 1386 sm_connection->sm_pairing_requested = 0; 1387 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1388 #endif 1389 break; 1390 1391 default: 1392 btstack_assert(false); 1393 break; 1394 } 1395 break; 1396 default: 1397 break; 1398 } 1399 1400 switch (event){ 1401 case ADDRESS_RESOLUTION_SUCCEEDED: 1402 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1403 break; 1404 case ADDRESS_RESOLUTION_FAILED: 1405 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1406 break; 1407 default: 1408 btstack_assert(false); 1409 break; 1410 } 1411 } 1412 1413 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1414 int le_db_index = -1; 1415 1416 // lookup device based on IRK 1417 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1418 int i; 1419 for (i=0; i < le_device_db_max_count(); i++){ 1420 sm_key_t irk; 1421 bd_addr_t address; 1422 int address_type = BD_ADDR_TYPE_UNKNOWN; 1423 le_device_db_info(i, &address_type, address, irk); 1424 // skip unused entries 1425 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1426 // compare IRK 1427 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1428 1429 log_info("sm: device found for IRK, updating"); 1430 le_db_index = i; 1431 break; 1432 } 1433 } else { 1434 // assert IRK is set to zero 1435 memset(setup->sm_peer_irk, 0, 16); 1436 } 1437 1438 // if not found, lookup via public address if possible 1439 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1440 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1441 int i; 1442 for (i=0; i < le_device_db_max_count(); i++){ 1443 bd_addr_t address; 1444 int address_type = BD_ADDR_TYPE_UNKNOWN; 1445 le_device_db_info(i, &address_type, address, NULL); 1446 // skip unused entries 1447 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1448 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1449 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1450 log_info("sm: device found for public address, updating"); 1451 le_db_index = i; 1452 break; 1453 } 1454 } 1455 } 1456 1457 // if not found, add to db 1458 bool new_to_le_device_db = false; 1459 if (le_db_index < 0) { 1460 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1461 new_to_le_device_db = true; 1462 } 1463 1464 if (le_db_index >= 0){ 1465 1466 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1467 if (!new_to_le_device_db){ 1468 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1469 } 1470 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1471 #else 1472 UNUSED(new_to_le_device_db); 1473 #endif 1474 1475 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1476 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1477 sm_conn->sm_le_db_index = le_db_index; 1478 1479 #ifdef ENABLE_LE_SIGNED_WRITE 1480 // store local CSRK 1481 setup->sm_le_device_index = le_db_index; 1482 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1483 log_info("sm: store local CSRK"); 1484 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1485 le_device_db_local_counter_set(le_db_index, 0); 1486 } 1487 1488 // store remote CSRK 1489 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1490 log_info("sm: store remote CSRK"); 1491 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1492 le_device_db_remote_counter_set(le_db_index, 0); 1493 } 1494 #endif 1495 // store encryption information for secure connections: LTK generated by ECDH 1496 if (setup->sm_use_secure_connections){ 1497 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1498 uint8_t zero_rand[8]; 1499 memset(zero_rand, 0, 8); 1500 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1501 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1502 } 1503 1504 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1505 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1506 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1507 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1508 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1509 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1510 1511 } 1512 } 1513 } 1514 1515 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1516 1517 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1518 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1519 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1520 & SM_AUTHREQ_BONDING ) != 0u; 1521 1522 if (bonding_enabled){ 1523 sm_store_bonding_information(sm_conn); 1524 } else { 1525 log_info("Ignoring received keys, bonding not enabled"); 1526 } 1527 } 1528 1529 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1530 sm_conn->sm_pairing_failed_reason = reason; 1531 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1532 } 1533 1534 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1535 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1536 } 1537 1538 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1539 1540 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1541 static int sm_passkey_used(stk_generation_method_t method); 1542 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1543 1544 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1545 if (setup->sm_stk_generation_method == OOB){ 1546 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1547 } else { 1548 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); 1549 } 1550 } 1551 1552 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1553 if (IS_RESPONDER(sm_conn->sm_role)){ 1554 // Responder 1555 if (setup->sm_stk_generation_method == OOB){ 1556 // generate Nb 1557 log_info("Generate Nb"); 1558 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); 1559 } else { 1560 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1561 } 1562 } else { 1563 // Initiator role 1564 switch (setup->sm_stk_generation_method){ 1565 case JUST_WORKS: 1566 sm_sc_prepare_dhkey_check(sm_conn); 1567 break; 1568 1569 case NUMERIC_COMPARISON: 1570 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1571 break; 1572 case PK_INIT_INPUT: 1573 case PK_RESP_INPUT: 1574 case PK_BOTH_INPUT: 1575 if (setup->sm_passkey_bit < 20u) { 1576 sm_sc_start_calculating_local_confirm(sm_conn); 1577 } else { 1578 sm_sc_prepare_dhkey_check(sm_conn); 1579 } 1580 break; 1581 case OOB: 1582 sm_sc_prepare_dhkey_check(sm_conn); 1583 break; 1584 default: 1585 btstack_assert(false); 1586 break; 1587 } 1588 } 1589 } 1590 1591 static void sm_sc_cmac_done(uint8_t * hash){ 1592 log_info("sm_sc_cmac_done: "); 1593 log_info_hexdump(hash, 16); 1594 1595 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1596 sm_sc_oob_state = SM_SC_OOB_IDLE; 1597 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1598 return; 1599 } 1600 1601 sm_connection_t * sm_conn = sm_cmac_connection; 1602 sm_cmac_connection = NULL; 1603 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1604 link_key_type_t link_key_type; 1605 #endif 1606 1607 switch (sm_conn->sm_engine_state){ 1608 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1609 (void)memcpy(setup->sm_local_confirm, hash, 16); 1610 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1611 break; 1612 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1613 // check 1614 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1615 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1616 break; 1617 } 1618 sm_sc_state_after_receiving_random(sm_conn); 1619 break; 1620 case SM_SC_W4_CALCULATE_G2: { 1621 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1622 big_endian_store_32(setup->sm_tk, 12, vab); 1623 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1624 sm_trigger_user_response(sm_conn); 1625 break; 1626 } 1627 case SM_SC_W4_CALCULATE_F5_SALT: 1628 (void)memcpy(setup->sm_t, hash, 16); 1629 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1630 break; 1631 case SM_SC_W4_CALCULATE_F5_MACKEY: 1632 (void)memcpy(setup->sm_mackey, hash, 16); 1633 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1634 break; 1635 case SM_SC_W4_CALCULATE_F5_LTK: 1636 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1637 // Errata Service Release to the Bluetooth Specification: ESR09 1638 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1639 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1640 (void)memcpy(setup->sm_ltk, hash, 16); 1641 (void)memcpy(setup->sm_local_ltk, hash, 16); 1642 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1643 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1644 break; 1645 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1646 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1647 if (IS_RESPONDER(sm_conn->sm_role)){ 1648 // responder 1649 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1650 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1651 } else { 1652 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1653 } 1654 } else { 1655 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1656 } 1657 break; 1658 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1659 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1660 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1661 break; 1662 } 1663 if (IS_RESPONDER(sm_conn->sm_role)){ 1664 // responder 1665 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1666 } else { 1667 // initiator 1668 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1669 } 1670 break; 1671 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1672 case SM_SC_W4_CALCULATE_ILK: 1673 (void)memcpy(setup->sm_t, hash, 16); 1674 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1675 break; 1676 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1677 reverse_128(hash, setup->sm_t); 1678 link_key_type = sm_conn->sm_connection_authenticated ? 1679 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1680 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1681 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1682 if (IS_RESPONDER(sm_conn->sm_role)){ 1683 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1684 } else { 1685 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1686 } 1687 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1688 sm_done_for_handle(sm_conn->sm_handle); 1689 break; 1690 #endif 1691 default: 1692 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1693 break; 1694 } 1695 sm_trigger_run(); 1696 } 1697 1698 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){ 1699 const uint16_t message_len = 65; 1700 sm_cmac_connection = sm_conn; 1701 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1702 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1703 sm_cmac_sc_buffer[64] = z; 1704 log_info("f4 key"); 1705 log_info_hexdump(x, 16); 1706 log_info("f4 message"); 1707 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1708 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1709 } 1710 1711 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1712 static const uint8_t f5_length[] = { 0x01, 0x00}; 1713 1714 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1715 1716 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1717 1718 log_info("f5_calculate_salt"); 1719 // calculate salt for f5 1720 const uint16_t message_len = 32; 1721 sm_cmac_connection = sm_conn; 1722 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1723 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1724 } 1725 1726 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){ 1727 const uint16_t message_len = 53; 1728 sm_cmac_connection = sm_conn; 1729 1730 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1731 sm_cmac_sc_buffer[0] = 0; 1732 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1733 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1734 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1735 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1736 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1737 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1738 log_info("f5 key"); 1739 log_info_hexdump(t, 16); 1740 log_info("f5 message for MacKey"); 1741 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1742 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1743 } 1744 1745 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1746 sm_key56_t bd_addr_master, bd_addr_slave; 1747 bd_addr_master[0] = setup->sm_m_addr_type; 1748 bd_addr_slave[0] = setup->sm_s_addr_type; 1749 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1750 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1751 if (IS_RESPONDER(sm_conn->sm_role)){ 1752 // responder 1753 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1754 } else { 1755 // initiator 1756 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1757 } 1758 } 1759 1760 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1761 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1762 const uint16_t message_len = 53; 1763 sm_cmac_connection = sm_conn; 1764 sm_cmac_sc_buffer[0] = 1; 1765 // 1..52 setup before 1766 log_info("f5 key"); 1767 log_info_hexdump(t, 16); 1768 log_info("f5 message for LTK"); 1769 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1770 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1771 } 1772 1773 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1774 f5_ltk(sm_conn, setup->sm_t); 1775 } 1776 1777 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){ 1778 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1779 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1780 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1781 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1782 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1783 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1784 } 1785 1786 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1787 const uint16_t message_len = 65; 1788 sm_cmac_connection = sm_conn; 1789 log_info("f6 key"); 1790 log_info_hexdump(w, 16); 1791 log_info("f6 message"); 1792 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1793 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1794 } 1795 1796 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1797 // - U is 256 bits 1798 // - V is 256 bits 1799 // - X is 128 bits 1800 // - Y is 128 bits 1801 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){ 1802 const uint16_t message_len = 80; 1803 sm_cmac_connection = sm_conn; 1804 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1805 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1806 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1807 log_info("g2 key"); 1808 log_info_hexdump(x, 16); 1809 log_info("g2 message"); 1810 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1811 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1812 } 1813 1814 static void g2_calculate(sm_connection_t * sm_conn) { 1815 // calc Va if numeric comparison 1816 if (IS_RESPONDER(sm_conn->sm_role)){ 1817 // responder 1818 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1819 } else { 1820 // initiator 1821 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1822 } 1823 } 1824 1825 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1826 uint8_t z = 0; 1827 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1828 // some form of passkey 1829 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1830 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1831 setup->sm_passkey_bit++; 1832 } 1833 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1834 } 1835 1836 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1837 // OOB 1838 if (setup->sm_stk_generation_method == OOB){ 1839 if (IS_RESPONDER(sm_conn->sm_role)){ 1840 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1841 } else { 1842 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1843 } 1844 return; 1845 } 1846 1847 uint8_t z = 0; 1848 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1849 // some form of passkey 1850 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1851 // sm_passkey_bit was increased before sending confirm value 1852 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1853 } 1854 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1855 } 1856 1857 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1858 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1859 1860 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1861 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1862 return; 1863 } else { 1864 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1865 } 1866 } 1867 1868 static void sm_sc_dhkey_calculated(void * arg){ 1869 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1870 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1871 if (sm_conn == NULL) return; 1872 1873 log_info("dhkey"); 1874 log_info_hexdump(&setup->sm_dhkey[0], 32); 1875 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1876 // trigger next step 1877 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1878 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1879 } 1880 sm_trigger_run(); 1881 } 1882 1883 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1884 // calculate DHKCheck 1885 sm_key56_t bd_addr_master, bd_addr_slave; 1886 bd_addr_master[0] = setup->sm_m_addr_type; 1887 bd_addr_slave[0] = setup->sm_s_addr_type; 1888 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1889 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1890 uint8_t iocap_a[3]; 1891 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1892 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1893 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1894 uint8_t iocap_b[3]; 1895 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1896 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1897 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1898 if (IS_RESPONDER(sm_conn->sm_role)){ 1899 // responder 1900 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1901 f6_engine(sm_conn, setup->sm_mackey); 1902 } else { 1903 // initiator 1904 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1905 f6_engine(sm_conn, setup->sm_mackey); 1906 } 1907 } 1908 1909 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1910 // validate E = f6() 1911 sm_key56_t bd_addr_master, bd_addr_slave; 1912 bd_addr_master[0] = setup->sm_m_addr_type; 1913 bd_addr_slave[0] = setup->sm_s_addr_type; 1914 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1915 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1916 1917 uint8_t iocap_a[3]; 1918 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1919 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1920 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1921 uint8_t iocap_b[3]; 1922 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1923 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1924 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1925 if (IS_RESPONDER(sm_conn->sm_role)){ 1926 // responder 1927 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1928 f6_engine(sm_conn, setup->sm_mackey); 1929 } else { 1930 // initiator 1931 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1932 f6_engine(sm_conn, setup->sm_mackey); 1933 } 1934 } 1935 1936 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1937 1938 // 1939 // Link Key Conversion Function h6 1940 // 1941 // h6(W, keyID) = AES-CMAC_W(keyID) 1942 // - W is 128 bits 1943 // - keyID is 32 bits 1944 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1945 const uint16_t message_len = 4; 1946 sm_cmac_connection = sm_conn; 1947 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1948 log_info("h6 key"); 1949 log_info_hexdump(w, 16); 1950 log_info("h6 message"); 1951 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1952 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1953 } 1954 // 1955 // Link Key Conversion Function h7 1956 // 1957 // h7(SALT, W) = AES-CMAC_SALT(W) 1958 // - SALT is 128 bits 1959 // - W is 128 bits 1960 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1961 const uint16_t message_len = 16; 1962 sm_cmac_connection = sm_conn; 1963 log_info("h7 key"); 1964 log_info_hexdump(salt, 16); 1965 log_info("h7 message"); 1966 log_info_hexdump(w, 16); 1967 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1968 } 1969 1970 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1971 // Errata Service Release to the Bluetooth Specification: ESR09 1972 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1973 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1974 1975 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 1976 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1977 } 1978 1979 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1980 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1981 } 1982 1983 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 1984 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1985 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1986 } 1987 #endif 1988 1989 #endif 1990 1991 // key management legacy connections: 1992 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1993 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1994 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1995 // - responder reconnects: responder uses LTK receveived from master 1996 1997 // key management secure connections: 1998 // - both devices store same LTK from ECDH key exchange. 1999 2000 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2001 static void sm_load_security_info(sm_connection_t * sm_connection){ 2002 int encryption_key_size; 2003 int authenticated; 2004 int authorized; 2005 int secure_connection; 2006 2007 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2008 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2009 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2010 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); 2011 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2012 sm_connection->sm_connection_authenticated = authenticated; 2013 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2014 sm_connection->sm_connection_sc = secure_connection; 2015 } 2016 #endif 2017 2018 #ifdef ENABLE_LE_PERIPHERAL 2019 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2020 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2021 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2022 // re-establish used key encryption size 2023 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2024 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2025 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2026 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2027 // Legacy paring -> not SC 2028 sm_connection->sm_connection_sc = 0; 2029 log_info("sm: received ltk request with key size %u, authenticated %u", 2030 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2031 } 2032 #endif 2033 2034 // distributed key generation 2035 static bool sm_run_dpkg(void){ 2036 switch (dkg_state){ 2037 case DKG_CALC_IRK: 2038 // already busy? 2039 if (sm_aes128_state == SM_AES128_IDLE) { 2040 log_info("DKG_CALC_IRK started"); 2041 // IRK = d1(IR, 1, 0) 2042 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2043 sm_aes128_state = SM_AES128_ACTIVE; 2044 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2045 return true; 2046 } 2047 break; 2048 case DKG_CALC_DHK: 2049 // already busy? 2050 if (sm_aes128_state == SM_AES128_IDLE) { 2051 log_info("DKG_CALC_DHK started"); 2052 // DHK = d1(IR, 3, 0) 2053 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2054 sm_aes128_state = SM_AES128_ACTIVE; 2055 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2056 return true; 2057 } 2058 break; 2059 default: 2060 break; 2061 } 2062 return false; 2063 } 2064 2065 // random address updates 2066 static bool sm_run_rau(void){ 2067 switch (rau_state){ 2068 case RAU_GET_RANDOM: 2069 rau_state = RAU_W4_RANDOM; 2070 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2071 return true; 2072 case RAU_GET_ENC: 2073 // already busy? 2074 if (sm_aes128_state == SM_AES128_IDLE) { 2075 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2076 sm_aes128_state = SM_AES128_ACTIVE; 2077 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2078 return true; 2079 } 2080 break; 2081 case RAU_SET_ADDRESS: 2082 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2083 rau_state = RAU_IDLE; 2084 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2085 return true; 2086 default: 2087 break; 2088 } 2089 return false; 2090 } 2091 2092 // CSRK Lookup 2093 static bool sm_run_csrk(void){ 2094 btstack_linked_list_iterator_t it; 2095 2096 // -- if csrk lookup ready, find connection that require csrk lookup 2097 if (sm_address_resolution_idle()){ 2098 hci_connections_get_iterator(&it); 2099 while(btstack_linked_list_iterator_has_next(&it)){ 2100 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2101 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2102 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2103 // and start lookup 2104 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); 2105 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2106 break; 2107 } 2108 } 2109 } 2110 2111 // -- if csrk lookup ready, resolved addresses for received addresses 2112 if (sm_address_resolution_idle()) { 2113 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2114 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2115 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2116 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2117 btstack_memory_sm_lookup_entry_free(entry); 2118 } 2119 } 2120 2121 // -- Continue with CSRK device lookup by public or resolvable private address 2122 if (!sm_address_resolution_idle()){ 2123 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2124 while (sm_address_resolution_test < le_device_db_max_count()){ 2125 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2126 bd_addr_t addr; 2127 sm_key_t irk; 2128 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2129 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2130 2131 // skip unused entries 2132 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2133 sm_address_resolution_test++; 2134 continue; 2135 } 2136 2137 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2138 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2139 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2140 break; 2141 } 2142 2143 // if connection type is public, it must be a different one 2144 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2145 sm_address_resolution_test++; 2146 continue; 2147 } 2148 2149 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2150 2151 log_info("LE Device Lookup: calculate AH"); 2152 log_info_key("IRK", irk); 2153 2154 (void)memcpy(sm_aes128_key, irk, 16); 2155 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2156 sm_address_resolution_ah_calculation_active = 1; 2157 sm_aes128_state = SM_AES128_ACTIVE; 2158 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2159 return true; 2160 } 2161 2162 if (sm_address_resolution_test >= le_device_db_max_count()){ 2163 log_info("LE Device Lookup: not found"); 2164 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2165 } 2166 } 2167 return false; 2168 } 2169 2170 // SC OOB 2171 static bool sm_run_oob(void){ 2172 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2173 switch (sm_sc_oob_state){ 2174 case SM_SC_OOB_W2_CALC_CONFIRM: 2175 if (!sm_cmac_ready()) break; 2176 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2177 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2178 return true; 2179 default: 2180 break; 2181 } 2182 #endif 2183 return false; 2184 } 2185 2186 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2187 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2188 } 2189 2190 // handle basic actions that don't requires the full context 2191 static bool sm_run_basic(void){ 2192 btstack_linked_list_iterator_t it; 2193 hci_connections_get_iterator(&it); 2194 while(btstack_linked_list_iterator_has_next(&it)){ 2195 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2196 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2197 switch(sm_connection->sm_engine_state){ 2198 2199 // general 2200 case SM_GENERAL_SEND_PAIRING_FAILED: { 2201 uint8_t buffer[2]; 2202 buffer[0] = SM_CODE_PAIRING_FAILED; 2203 buffer[1] = sm_connection->sm_pairing_failed_reason; 2204 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2205 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2206 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2207 sm_done_for_handle(sm_connection->sm_handle); 2208 break; 2209 } 2210 2211 // responder side 2212 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2213 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2214 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2215 return true; 2216 2217 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2218 case SM_SC_RECEIVED_LTK_REQUEST: 2219 switch (sm_connection->sm_irk_lookup_state){ 2220 case IRK_LOOKUP_FAILED: 2221 log_info("LTK Request: IRK Lookup Failed)"); 2222 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2223 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2224 return true; 2225 default: 2226 break; 2227 } 2228 break; 2229 #endif 2230 default: 2231 break; 2232 } 2233 } 2234 return false; 2235 } 2236 2237 static void sm_run_activate_connection(void){ 2238 // Find connections that requires setup context and make active if no other is locked 2239 btstack_linked_list_iterator_t it; 2240 hci_connections_get_iterator(&it); 2241 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2242 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2243 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2244 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2245 bool done = true; 2246 int err; 2247 UNUSED(err); 2248 2249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2250 // assert ec key is ready 2251 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2252 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2253 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2254 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2255 sm_ec_generate_new_key(); 2256 } 2257 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2258 continue; 2259 } 2260 } 2261 #endif 2262 2263 switch (sm_connection->sm_engine_state) { 2264 #ifdef ENABLE_LE_PERIPHERAL 2265 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2266 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2267 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2269 case SM_SC_RECEIVED_LTK_REQUEST: 2270 #endif 2271 #endif 2272 #ifdef ENABLE_LE_CENTRAL 2273 case SM_INITIATOR_PH4_HAS_LTK: 2274 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2275 #endif 2276 // just lock context 2277 break; 2278 default: 2279 done = false; 2280 break; 2281 } 2282 if (done){ 2283 sm_active_connection_handle = sm_connection->sm_handle; 2284 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); 2285 } 2286 } 2287 } 2288 2289 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2290 int i; 2291 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2292 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2293 uint8_t action = 0; 2294 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2295 if (flags & (1u<<i)){ 2296 bool clear_flag = true; 2297 switch (i){ 2298 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2299 case SM_KEYPRESS_PASSKEY_CLEARED: 2300 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2301 default: 2302 break; 2303 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2304 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2305 num_actions--; 2306 clear_flag = num_actions == 0u; 2307 break; 2308 } 2309 if (clear_flag){ 2310 flags &= ~(1<<i); 2311 } 2312 action = i; 2313 break; 2314 } 2315 } 2316 setup->sm_keypress_notification = (num_actions << 5) | flags; 2317 2318 // send keypress notification 2319 uint8_t buffer[2]; 2320 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2321 buffer[1] = action; 2322 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2323 2324 // try 2325 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2326 } 2327 2328 static void sm_run_distribute_keys(sm_connection_t * connection){ 2329 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2330 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2331 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2332 uint8_t buffer[17]; 2333 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2334 reverse_128(setup->sm_ltk, &buffer[1]); 2335 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2336 sm_timeout_reset(connection); 2337 return; 2338 } 2339 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2340 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2341 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2342 uint8_t buffer[11]; 2343 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2344 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2345 reverse_64(setup->sm_local_rand, &buffer[3]); 2346 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2347 sm_timeout_reset(connection); 2348 return; 2349 } 2350 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2351 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2352 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2353 uint8_t buffer[17]; 2354 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2355 reverse_128(sm_persistent_irk, &buffer[1]); 2356 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2357 sm_timeout_reset(connection); 2358 return; 2359 } 2360 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2361 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2362 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2363 bd_addr_t local_address; 2364 uint8_t buffer[8]; 2365 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2366 switch (gap_random_address_get_mode()){ 2367 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2368 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2369 // public or static random 2370 gap_le_get_own_address(&buffer[1], local_address); 2371 break; 2372 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2373 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2374 // fallback to public 2375 gap_local_bd_addr(local_address); 2376 buffer[1] = 0; 2377 break; 2378 default: 2379 btstack_assert(false); 2380 break; 2381 } 2382 reverse_bd_addr(local_address, &buffer[2]); 2383 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2384 sm_timeout_reset(connection); 2385 return; 2386 } 2387 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2388 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2389 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2390 2391 #ifdef ENABLE_LE_SIGNED_WRITE 2392 // hack to reproduce test runs 2393 if (test_use_fixed_local_csrk){ 2394 memset(setup->sm_local_csrk, 0xcc, 16); 2395 } 2396 2397 // store local CSRK 2398 if (setup->sm_le_device_index >= 0){ 2399 log_info("sm: store local CSRK"); 2400 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2401 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2402 } 2403 #endif 2404 2405 uint8_t buffer[17]; 2406 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2407 reverse_128(setup->sm_local_csrk, &buffer[1]); 2408 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2409 sm_timeout_reset(connection); 2410 return; 2411 } 2412 btstack_assert(false); 2413 } 2414 2415 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2416 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2417 // requirements to derive link key from LE: 2418 // - use secure connections 2419 if (setup->sm_use_secure_connections == 0) return false; 2420 // - bonding needs to be enabled: 2421 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; 2422 if (!bonding_enabled) return false; 2423 // - need identity address / public addr 2424 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2425 if (!have_identity_address_info) return false; 2426 // - 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) 2427 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2428 // If SC is authenticated, we consider it safe to overwrite a stored key. 2429 // 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. 2430 uint8_t link_key[16]; 2431 link_key_type_t link_key_type; 2432 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2433 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 2434 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2435 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2436 return false; 2437 } 2438 // get started (all of the above are true) 2439 return true; 2440 #else 2441 UNUSED(sm_connection); 2442 return false; 2443 #endif 2444 } 2445 2446 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2447 if (sm_ctkd_from_le(connection)){ 2448 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; 2449 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2450 } else { 2451 connection->sm_engine_state = SM_RESPONDER_IDLE; 2452 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2453 sm_done_for_handle(connection->sm_handle); 2454 } 2455 } 2456 2457 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2458 if (sm_ctkd_from_le(connection)){ 2459 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; 2460 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2461 } else { 2462 sm_master_pairing_success(connection); 2463 } 2464 } 2465 2466 static void sm_run(void){ 2467 2468 // assert that stack has already bootet 2469 if (hci_get_state() != HCI_STATE_WORKING) return; 2470 2471 // assert that we can send at least commands 2472 if (!hci_can_send_command_packet_now()) return; 2473 2474 // pause until IR/ER are ready 2475 if (sm_persistent_keys_random_active) return; 2476 2477 bool done; 2478 2479 // 2480 // non-connection related behaviour 2481 // 2482 2483 done = sm_run_dpkg(); 2484 if (done) return; 2485 2486 done = sm_run_rau(); 2487 if (done) return; 2488 2489 done = sm_run_csrk(); 2490 if (done) return; 2491 2492 done = sm_run_oob(); 2493 if (done) return; 2494 2495 // assert that we can send at least commands - cmd might have been sent by crypto engine 2496 if (!hci_can_send_command_packet_now()) return; 2497 2498 // handle basic actions that don't requires the full context 2499 done = sm_run_basic(); 2500 if (done) return; 2501 2502 // 2503 // active connection handling 2504 // -- use loop to handle next connection if lock on setup context is released 2505 2506 while (true) { 2507 2508 sm_run_activate_connection(); 2509 2510 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2511 2512 // 2513 // active connection handling 2514 // 2515 2516 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2517 if (!connection) { 2518 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2519 return; 2520 } 2521 2522 // assert that we could send a SM PDU - not needed for all of the following 2523 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2524 log_info("cannot send now, requesting can send now event"); 2525 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2526 return; 2527 } 2528 2529 // send keypress notifications 2530 if (setup->sm_keypress_notification){ 2531 sm_run_send_keypress_notification(connection); 2532 return; 2533 } 2534 2535 int key_distribution_flags; 2536 UNUSED(key_distribution_flags); 2537 int err; 2538 UNUSED(err); 2539 bool have_ltk; 2540 uint8_t ltk[16]; 2541 2542 log_info("sm_run: state %u", connection->sm_engine_state); 2543 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2544 log_info("sm_run // cannot send"); 2545 } 2546 switch (connection->sm_engine_state){ 2547 2548 // secure connections, initiator + responding states 2549 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2550 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2551 if (!sm_cmac_ready()) break; 2552 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2553 sm_sc_calculate_local_confirm(connection); 2554 break; 2555 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2556 if (!sm_cmac_ready()) break; 2557 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2558 sm_sc_calculate_remote_confirm(connection); 2559 break; 2560 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2561 if (!sm_cmac_ready()) break; 2562 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2563 sm_sc_calculate_f6_for_dhkey_check(connection); 2564 break; 2565 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2566 if (!sm_cmac_ready()) break; 2567 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2568 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2569 break; 2570 case SM_SC_W2_CALCULATE_F5_SALT: 2571 if (!sm_cmac_ready()) break; 2572 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2573 f5_calculate_salt(connection); 2574 break; 2575 case SM_SC_W2_CALCULATE_F5_MACKEY: 2576 if (!sm_cmac_ready()) break; 2577 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2578 f5_calculate_mackey(connection); 2579 break; 2580 case SM_SC_W2_CALCULATE_F5_LTK: 2581 if (!sm_cmac_ready()) break; 2582 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2583 f5_calculate_ltk(connection); 2584 break; 2585 case SM_SC_W2_CALCULATE_G2: 2586 if (!sm_cmac_ready()) break; 2587 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2588 g2_calculate(connection); 2589 break; 2590 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2591 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2592 if (!sm_cmac_ready()) break; 2593 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2594 h6_calculate_ilk_from_le_ltk(connection); 2595 break; 2596 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2597 if (!sm_cmac_ready()) break; 2598 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2599 h6_calculate_br_edr_link_key(connection); 2600 break; 2601 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2602 if (!sm_cmac_ready()) break; 2603 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2604 h7_calculate_ilk_from_le_ltk(connection); 2605 break; 2606 #endif 2607 #endif 2608 2609 #ifdef ENABLE_LE_CENTRAL 2610 // initiator side 2611 2612 case SM_INITIATOR_PH4_HAS_LTK: { 2613 sm_reset_setup(); 2614 sm_load_security_info(connection); 2615 sm_reencryption_started(connection); 2616 2617 sm_key_t peer_ltk_flipped; 2618 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2619 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2620 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2621 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2622 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2623 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2624 return; 2625 } 2626 2627 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2628 sm_reset_setup(); 2629 sm_init_setup(connection); 2630 sm_timeout_start(connection); 2631 sm_pairing_started(connection); 2632 2633 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2634 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2635 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2636 sm_timeout_reset(connection); 2637 break; 2638 #endif 2639 2640 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2641 2642 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2643 bool trigger_user_response = false; 2644 bool trigger_start_calculating_local_confirm = false; 2645 uint8_t buffer[65]; 2646 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2647 // 2648 reverse_256(&ec_q[0], &buffer[1]); 2649 reverse_256(&ec_q[32], &buffer[33]); 2650 2651 #ifdef ENABLE_TESTING_SUPPORT 2652 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2653 log_info("testing_support: invalidating public key"); 2654 // flip single bit of public key coordinate 2655 buffer[1] ^= 1; 2656 } 2657 #endif 2658 2659 // stk generation method 2660 // passkey entry: notify app to show passkey or to request passkey 2661 switch (setup->sm_stk_generation_method){ 2662 case JUST_WORKS: 2663 case NUMERIC_COMPARISON: 2664 if (IS_RESPONDER(connection->sm_role)){ 2665 // responder 2666 trigger_start_calculating_local_confirm = true; 2667 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2668 } else { 2669 // initiator 2670 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2671 } 2672 break; 2673 case PK_INIT_INPUT: 2674 case PK_RESP_INPUT: 2675 case PK_BOTH_INPUT: 2676 // use random TK for display 2677 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2678 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2679 setup->sm_passkey_bit = 0; 2680 2681 if (IS_RESPONDER(connection->sm_role)){ 2682 // responder 2683 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2684 } else { 2685 // initiator 2686 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2687 } 2688 trigger_user_response = true; 2689 break; 2690 case OOB: 2691 if (IS_RESPONDER(connection->sm_role)){ 2692 // responder 2693 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2694 } else { 2695 // initiator 2696 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2697 } 2698 break; 2699 default: 2700 btstack_assert(false); 2701 break; 2702 } 2703 2704 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2705 sm_timeout_reset(connection); 2706 2707 // trigger user response and calc confirm after sending pdu 2708 if (trigger_user_response){ 2709 sm_trigger_user_response(connection); 2710 } 2711 if (trigger_start_calculating_local_confirm){ 2712 sm_sc_start_calculating_local_confirm(connection); 2713 } 2714 break; 2715 } 2716 case SM_SC_SEND_CONFIRMATION: { 2717 uint8_t buffer[17]; 2718 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2719 reverse_128(setup->sm_local_confirm, &buffer[1]); 2720 if (IS_RESPONDER(connection->sm_role)){ 2721 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2722 } else { 2723 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2724 } 2725 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2726 sm_timeout_reset(connection); 2727 break; 2728 } 2729 case SM_SC_SEND_PAIRING_RANDOM: { 2730 uint8_t buffer[17]; 2731 buffer[0] = SM_CODE_PAIRING_RANDOM; 2732 reverse_128(setup->sm_local_nonce, &buffer[1]); 2733 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2734 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2735 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2736 if (IS_RESPONDER(connection->sm_role)){ 2737 // responder 2738 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2739 } else { 2740 // initiator 2741 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2742 } 2743 } else { 2744 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2745 if (IS_RESPONDER(connection->sm_role)){ 2746 // responder 2747 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2748 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2749 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2750 } else { 2751 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2752 sm_sc_prepare_dhkey_check(connection); 2753 } 2754 } else { 2755 // initiator 2756 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2757 } 2758 } 2759 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2760 sm_timeout_reset(connection); 2761 break; 2762 } 2763 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2764 uint8_t buffer[17]; 2765 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2766 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2767 2768 if (IS_RESPONDER(connection->sm_role)){ 2769 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2770 } else { 2771 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2772 } 2773 2774 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2775 sm_timeout_reset(connection); 2776 break; 2777 } 2778 2779 #endif 2780 2781 #ifdef ENABLE_LE_PERIPHERAL 2782 2783 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2784 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2785 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2786 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2787 sm_timeout_start(connection); 2788 break; 2789 } 2790 2791 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2792 case SM_SC_RECEIVED_LTK_REQUEST: 2793 switch (connection->sm_irk_lookup_state){ 2794 case IRK_LOOKUP_SUCCEEDED: 2795 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2796 // start using context by loading security info 2797 sm_reset_setup(); 2798 sm_load_security_info(connection); 2799 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2800 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2801 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2802 sm_reencryption_started(connection); 2803 sm_trigger_run(); 2804 break; 2805 } 2806 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2807 connection->sm_engine_state = SM_RESPONDER_IDLE; 2808 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2809 return; 2810 default: 2811 // just wait until IRK lookup is completed 2812 break; 2813 } 2814 break; 2815 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2816 2817 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2818 sm_reset_setup(); 2819 2820 // handle Pairing Request with LTK available 2821 switch (connection->sm_irk_lookup_state) { 2822 case IRK_LOOKUP_SUCCEEDED: 2823 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2824 have_ltk = !sm_is_null_key(ltk); 2825 if (have_ltk){ 2826 log_info("pairing request but LTK available"); 2827 // emit re-encryption start/fail sequence 2828 sm_reencryption_started(connection); 2829 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2830 } 2831 break; 2832 default: 2833 break; 2834 } 2835 2836 sm_init_setup(connection); 2837 sm_pairing_started(connection); 2838 2839 // recover pairing request 2840 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2841 err = sm_stk_generation_init(connection); 2842 2843 #ifdef ENABLE_TESTING_SUPPORT 2844 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2845 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2846 err = test_pairing_failure; 2847 } 2848 #endif 2849 if (err != 0){ 2850 sm_pairing_error(connection, err); 2851 sm_trigger_run(); 2852 break; 2853 } 2854 2855 sm_timeout_start(connection); 2856 2857 // generate random number first, if we need to show passkey, otherwise send response 2858 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2859 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2860 break; 2861 } 2862 2863 /* fall through */ 2864 2865 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2866 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2867 2868 // start with initiator key dist flags 2869 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2870 2871 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2872 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2873 if (setup->sm_use_secure_connections){ 2874 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2875 } 2876 #endif 2877 // setup in response 2878 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); 2879 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); 2880 2881 // update key distribution after ENC was dropped 2882 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)); 2883 2884 if (setup->sm_use_secure_connections){ 2885 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2886 } else { 2887 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2888 } 2889 2890 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2891 sm_timeout_reset(connection); 2892 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2893 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2894 sm_trigger_user_response(connection); 2895 } 2896 return; 2897 #endif 2898 2899 case SM_PH2_SEND_PAIRING_RANDOM: { 2900 uint8_t buffer[17]; 2901 buffer[0] = SM_CODE_PAIRING_RANDOM; 2902 reverse_128(setup->sm_local_random, &buffer[1]); 2903 if (IS_RESPONDER(connection->sm_role)){ 2904 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2905 } else { 2906 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2907 } 2908 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2909 sm_timeout_reset(connection); 2910 break; 2911 } 2912 2913 case SM_PH2_C1_GET_ENC_A: 2914 // already busy? 2915 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2916 // calculate confirm using aes128 engine - step 1 2917 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); 2918 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2919 sm_aes128_state = SM_AES128_ACTIVE; 2920 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); 2921 break; 2922 2923 case SM_PH2_C1_GET_ENC_C: 2924 // already busy? 2925 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2926 // calculate m_confirm using aes128 engine - step 1 2927 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); 2928 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2929 sm_aes128_state = SM_AES128_ACTIVE; 2930 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); 2931 break; 2932 2933 case SM_PH2_CALC_STK: 2934 // already busy? 2935 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2936 // calculate STK 2937 if (IS_RESPONDER(connection->sm_role)){ 2938 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2939 } else { 2940 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2941 } 2942 connection->sm_engine_state = SM_PH2_W4_STK; 2943 sm_aes128_state = SM_AES128_ACTIVE; 2944 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); 2945 break; 2946 2947 case SM_PH3_Y_GET_ENC: 2948 // already busy? 2949 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2950 // PH3B2 - calculate Y from - enc 2951 2952 // dm helper (was sm_dm_r_prime) 2953 // r' = padding || r 2954 // r - 64 bit value 2955 memset(&sm_aes128_plaintext[0], 0, 8); 2956 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2957 2958 // Y = dm(DHK, Rand) 2959 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2960 sm_aes128_state = SM_AES128_ACTIVE; 2961 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); 2962 break; 2963 2964 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2965 uint8_t buffer[17]; 2966 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2967 reverse_128(setup->sm_local_confirm, &buffer[1]); 2968 if (IS_RESPONDER(connection->sm_role)){ 2969 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2970 } else { 2971 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2972 } 2973 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2974 sm_timeout_reset(connection); 2975 return; 2976 } 2977 #ifdef ENABLE_LE_PERIPHERAL 2978 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2979 sm_key_t stk_flipped; 2980 reverse_128(setup->sm_ltk, stk_flipped); 2981 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2982 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2983 return; 2984 } 2985 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2986 sm_key_t ltk_flipped; 2987 reverse_128(setup->sm_ltk, ltk_flipped); 2988 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2989 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2990 return; 2991 } 2992 2993 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2994 // already busy? 2995 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2996 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2997 2998 sm_reset_setup(); 2999 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3000 3001 sm_reencryption_started(connection); 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_RESPONDER_PH4_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_ph4_y, (void *)(uintptr_t) connection->sm_handle); 3013 return; 3014 #endif 3015 #ifdef ENABLE_LE_CENTRAL 3016 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3017 sm_key_t stk_flipped; 3018 reverse_128(setup->sm_ltk, stk_flipped); 3019 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3020 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3021 return; 3022 } 3023 #endif 3024 3025 case SM_PH3_DISTRIBUTE_KEYS: 3026 if (setup->sm_key_distribution_send_set != 0){ 3027 sm_run_distribute_keys(connection); 3028 return; 3029 } 3030 3031 // keys are sent 3032 if (IS_RESPONDER(connection->sm_role)){ 3033 // slave -> receive master keys if any 3034 if (sm_key_distribution_all_received(connection)){ 3035 sm_key_distribution_handle_all_received(connection); 3036 sm_key_distribution_complete_responder(connection); 3037 // start CTKD right away 3038 continue; 3039 } else { 3040 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3041 } 3042 } else { 3043 sm_master_pairing_success(connection); 3044 } 3045 break; 3046 3047 default: 3048 break; 3049 } 3050 3051 // check again if active connection was released 3052 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3053 } 3054 } 3055 3056 // sm_aes128_state stays active 3057 static void sm_handle_encryption_result_enc_a(void *arg){ 3058 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3059 sm_aes128_state = SM_AES128_IDLE; 3060 3061 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3062 if (connection == NULL) return; 3063 3064 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3065 sm_aes128_state = SM_AES128_ACTIVE; 3066 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); 3067 } 3068 3069 static void sm_handle_encryption_result_enc_b(void *arg){ 3070 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3071 sm_aes128_state = SM_AES128_IDLE; 3072 3073 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3074 if (connection == NULL) return; 3075 3076 log_info_key("c1!", setup->sm_local_confirm); 3077 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3078 sm_trigger_run(); 3079 } 3080 3081 // sm_aes128_state stays active 3082 static void sm_handle_encryption_result_enc_c(void *arg){ 3083 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3084 sm_aes128_state = SM_AES128_IDLE; 3085 3086 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3087 if (connection == NULL) return; 3088 3089 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3090 sm_aes128_state = SM_AES128_ACTIVE; 3091 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); 3092 } 3093 3094 static void sm_handle_encryption_result_enc_d(void * arg){ 3095 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3096 sm_aes128_state = SM_AES128_IDLE; 3097 3098 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3099 if (connection == NULL) return; 3100 3101 log_info_key("c1!", sm_aes128_ciphertext); 3102 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3103 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3104 sm_trigger_run(); 3105 return; 3106 } 3107 if (IS_RESPONDER(connection->sm_role)){ 3108 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3109 sm_trigger_run(); 3110 } else { 3111 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3112 sm_aes128_state = SM_AES128_ACTIVE; 3113 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 3114 } 3115 } 3116 3117 static void sm_handle_encryption_result_enc_stk(void *arg){ 3118 sm_aes128_state = SM_AES128_IDLE; 3119 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3120 3121 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3122 if (connection == NULL) return; 3123 3124 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3125 log_info_key("stk", setup->sm_ltk); 3126 if (IS_RESPONDER(connection->sm_role)){ 3127 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3128 } else { 3129 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3130 } 3131 sm_trigger_run(); 3132 } 3133 3134 // sm_aes128_state stays active 3135 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3136 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3137 sm_aes128_state = SM_AES128_IDLE; 3138 3139 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3140 if (connection == NULL) return; 3141 3142 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3143 log_info_hex16("y", setup->sm_local_y); 3144 // PH3B3 - calculate EDIV 3145 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3146 log_info_hex16("ediv", setup->sm_local_ediv); 3147 // PH3B4 - calculate LTK - enc 3148 // LTK = d1(ER, DIV, 0)) 3149 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3150 sm_aes128_state = SM_AES128_ACTIVE; 3151 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); 3152 } 3153 3154 #ifdef ENABLE_LE_PERIPHERAL 3155 // sm_aes128_state stays active 3156 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3157 sm_aes128_state = SM_AES128_IDLE; 3158 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3159 3160 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3161 if (connection == NULL) return; 3162 3163 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3164 log_info_hex16("y", setup->sm_local_y); 3165 3166 // PH3B3 - calculate DIV 3167 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3168 log_info_hex16("ediv", setup->sm_local_ediv); 3169 // PH3B4 - calculate LTK - enc 3170 // LTK = d1(ER, DIV, 0)) 3171 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3172 sm_aes128_state = SM_AES128_ACTIVE; 3173 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); 3174 } 3175 #endif 3176 3177 // sm_aes128_state stays active 3178 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3179 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3180 sm_aes128_state = SM_AES128_IDLE; 3181 3182 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3183 if (connection == NULL) return; 3184 3185 log_info_key("ltk", setup->sm_ltk); 3186 // calc CSRK next 3187 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3188 sm_aes128_state = SM_AES128_ACTIVE; 3189 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); 3190 } 3191 3192 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3193 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3194 sm_aes128_state = SM_AES128_IDLE; 3195 3196 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3197 if (connection == NULL) return; 3198 3199 sm_aes128_state = SM_AES128_IDLE; 3200 log_info_key("csrk", setup->sm_local_csrk); 3201 if (setup->sm_key_distribution_send_set){ 3202 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3203 } else { 3204 // no keys to send, just continue 3205 if (IS_RESPONDER(connection->sm_role)){ 3206 if (sm_key_distribution_all_received(connection)){ 3207 sm_key_distribution_handle_all_received(connection); 3208 sm_key_distribution_complete_responder(connection); 3209 } else { 3210 // slave -> receive master keys 3211 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3212 } 3213 } else { 3214 sm_key_distribution_complete_initiator(connection); 3215 } 3216 } 3217 sm_trigger_run(); 3218 } 3219 3220 #ifdef ENABLE_LE_PERIPHERAL 3221 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3222 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3223 sm_aes128_state = SM_AES128_IDLE; 3224 3225 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3226 if (connection == NULL) return; 3227 3228 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3229 log_info_key("ltk", setup->sm_ltk); 3230 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3231 sm_trigger_run(); 3232 } 3233 #endif 3234 3235 static void sm_handle_encryption_result_address_resolution(void *arg){ 3236 UNUSED(arg); 3237 sm_aes128_state = SM_AES128_IDLE; 3238 3239 sm_address_resolution_ah_calculation_active = 0; 3240 // compare calulated address against connecting device 3241 uint8_t * hash = &sm_aes128_ciphertext[13]; 3242 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3243 log_info("LE Device Lookup: matched resolvable private address"); 3244 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3245 sm_trigger_run(); 3246 return; 3247 } 3248 // no match, try next 3249 sm_address_resolution_test++; 3250 sm_trigger_run(); 3251 } 3252 3253 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3254 UNUSED(arg); 3255 sm_aes128_state = SM_AES128_IDLE; 3256 3257 log_info_key("irk", sm_persistent_irk); 3258 dkg_state = DKG_CALC_DHK; 3259 sm_trigger_run(); 3260 } 3261 3262 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3263 UNUSED(arg); 3264 sm_aes128_state = SM_AES128_IDLE; 3265 3266 log_info_key("dhk", sm_persistent_dhk); 3267 dkg_state = DKG_READY; 3268 sm_trigger_run(); 3269 } 3270 3271 static void sm_handle_encryption_result_rau(void *arg){ 3272 UNUSED(arg); 3273 sm_aes128_state = SM_AES128_IDLE; 3274 3275 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3276 rau_state = RAU_SET_ADDRESS; 3277 sm_trigger_run(); 3278 } 3279 3280 static void sm_handle_random_result_rau(void * arg){ 3281 UNUSED(arg); 3282 // non-resolvable vs. resolvable 3283 switch (gap_random_adress_type){ 3284 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3285 // resolvable: use random as prand and calc address hash 3286 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3287 sm_random_address[0u] &= 0x3fu; 3288 sm_random_address[0u] |= 0x40u; 3289 rau_state = RAU_GET_ENC; 3290 break; 3291 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3292 default: 3293 // "The two most significant bits of the address shall be equal to ‘0’"" 3294 sm_random_address[0u] &= 0x3fu; 3295 rau_state = RAU_SET_ADDRESS; 3296 break; 3297 } 3298 sm_trigger_run(); 3299 } 3300 3301 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3302 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3303 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3304 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3305 if (connection == NULL) return; 3306 3307 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3308 sm_trigger_run(); 3309 } 3310 3311 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3312 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3313 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3314 if (connection == NULL) return; 3315 3316 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3317 sm_trigger_run(); 3318 } 3319 #endif 3320 3321 static void sm_handle_random_result_ph2_random(void * arg){ 3322 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3323 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3324 if (connection == NULL) return; 3325 3326 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3327 sm_trigger_run(); 3328 } 3329 3330 static void sm_handle_random_result_ph2_tk(void * arg){ 3331 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3332 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3333 if (connection == NULL) return; 3334 3335 sm_reset_tk(); 3336 uint32_t tk; 3337 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3338 // map random to 0-999999 without speding much cycles on a modulus operation 3339 tk = little_endian_read_32(sm_random_data,0); 3340 tk = tk & 0xfffff; // 1048575 3341 if (tk >= 999999u){ 3342 tk = tk - 999999u; 3343 } 3344 } else { 3345 // override with pre-defined passkey 3346 tk = sm_fixed_passkey_in_display_role; 3347 } 3348 big_endian_store_32(setup->sm_tk, 12, tk); 3349 if (IS_RESPONDER(connection->sm_role)){ 3350 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3351 } else { 3352 if (setup->sm_use_secure_connections){ 3353 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3354 } else { 3355 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3356 sm_trigger_user_response(connection); 3357 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3358 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3359 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); 3360 } 3361 } 3362 } 3363 sm_trigger_run(); 3364 } 3365 3366 static void sm_handle_random_result_ph3_div(void * arg){ 3367 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3368 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3369 if (connection == NULL) return; 3370 3371 // use 16 bit from random value as div 3372 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3373 log_info_hex16("div", setup->sm_local_div); 3374 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3375 sm_trigger_run(); 3376 } 3377 3378 static void sm_handle_random_result_ph3_random(void * arg){ 3379 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3380 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3381 if (connection == NULL) return; 3382 3383 reverse_64(sm_random_data, setup->sm_local_rand); 3384 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3385 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3386 // no db for authenticated flag hack: store flag in bit 4 of LSB 3387 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3388 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3389 } 3390 static void sm_validate_er_ir(void){ 3391 // warn about default ER/IR 3392 bool warning = false; 3393 if (sm_ir_is_default()){ 3394 warning = true; 3395 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3396 } 3397 if (sm_er_is_default()){ 3398 warning = true; 3399 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3400 } 3401 if (warning) { 3402 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3403 } 3404 } 3405 3406 static void sm_handle_random_result_ir(void *arg){ 3407 sm_persistent_keys_random_active = false; 3408 if (arg != NULL){ 3409 // key generated, store in tlv 3410 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3411 log_info("Generated IR key. Store in TLV status: %d", status); 3412 UNUSED(status); 3413 } 3414 log_info_key("IR", sm_persistent_ir); 3415 dkg_state = DKG_CALC_IRK; 3416 3417 if (test_use_fixed_local_irk){ 3418 log_info_key("IRK", sm_persistent_irk); 3419 dkg_state = DKG_CALC_DHK; 3420 } 3421 3422 sm_trigger_run(); 3423 } 3424 3425 static void sm_handle_random_result_er(void *arg){ 3426 sm_persistent_keys_random_active = false; 3427 if (arg != 0){ 3428 // key generated, store in tlv 3429 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3430 log_info("Generated ER key. Store in TLV status: %d", status); 3431 UNUSED(status); 3432 } 3433 log_info_key("ER", sm_persistent_er); 3434 3435 // try load ir 3436 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3437 if (key_size == 16){ 3438 // ok, let's continue 3439 log_info("IR from TLV"); 3440 sm_handle_random_result_ir( NULL ); 3441 } else { 3442 // invalid, generate new random one 3443 sm_persistent_keys_random_active = true; 3444 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3445 } 3446 } 3447 3448 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){ 3449 3450 // connection info 3451 sm_conn->sm_handle = con_handle; 3452 sm_conn->sm_role = role; 3453 sm_conn->sm_peer_addr_type = addr_type; 3454 memcpy(sm_conn->sm_peer_address, address, 6); 3455 3456 // security properties 3457 sm_conn->sm_connection_encrypted = 0; 3458 sm_conn->sm_connection_authenticated = 0; 3459 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3460 sm_conn->sm_le_db_index = -1; 3461 sm_conn->sm_reencryption_active = false; 3462 3463 // prepare CSRK lookup (does not involve setup) 3464 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3465 3466 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3467 } 3468 3469 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3470 3471 UNUSED(channel); // ok: there is no channel 3472 UNUSED(size); // ok: fixed format HCI events 3473 3474 sm_connection_t * sm_conn; 3475 hci_con_handle_t con_handle; 3476 uint8_t status; 3477 bd_addr_t addr; 3478 3479 switch (packet_type) { 3480 3481 case HCI_EVENT_PACKET: 3482 switch (hci_event_packet_get_type(packet)) { 3483 3484 case BTSTACK_EVENT_STATE: 3485 // bt stack activated, get started 3486 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3487 log_info("HCI Working!"); 3488 3489 // setup IR/ER with TLV 3490 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3491 if (sm_tlv_impl != NULL){ 3492 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3493 if (key_size == 16){ 3494 // ok, let's continue 3495 log_info("ER from TLV"); 3496 sm_handle_random_result_er( NULL ); 3497 } else { 3498 // invalid, generate random one 3499 sm_persistent_keys_random_active = true; 3500 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3501 } 3502 } else { 3503 sm_validate_er_ir(); 3504 dkg_state = DKG_CALC_IRK; 3505 3506 if (test_use_fixed_local_irk){ 3507 log_info_key("IRK", sm_persistent_irk); 3508 dkg_state = DKG_CALC_DHK; 3509 } 3510 } 3511 3512 // restart random address updates after power cycle 3513 gap_random_address_set_mode(gap_random_adress_type); 3514 } 3515 break; 3516 #ifdef ENABLE_CLASSIC 3517 case HCI_EVENT_CONNECTION_COMPLETE: 3518 // ignore if connection failed 3519 if (hci_event_connection_complete_get_status(packet)) return; 3520 3521 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3522 sm_conn = sm_get_connection_for_handle(con_handle); 3523 if (!sm_conn) break; 3524 3525 hci_event_connection_complete_get_bd_addr(packet, addr); 3526 sm_connection_init(sm_conn, 3527 con_handle, 3528 (uint8_t) gap_get_role(con_handle), 3529 BD_ADDR_TYPE_LE_PUBLIC, 3530 addr); 3531 // classic connection corresponds to public le address 3532 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3533 gap_local_bd_addr(sm_conn->sm_own_address); 3534 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3535 break; 3536 #endif 3537 case HCI_EVENT_LE_META: 3538 switch (packet[2]) { 3539 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3540 // ignore if connection failed 3541 if (packet[3]) return; 3542 3543 con_handle = little_endian_read_16(packet, 4); 3544 sm_conn = sm_get_connection_for_handle(con_handle); 3545 if (!sm_conn) break; 3546 3547 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3548 sm_connection_init(sm_conn, 3549 con_handle, 3550 hci_subevent_le_connection_complete_get_role(packet), 3551 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3552 addr); 3553 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3554 3555 // track our addr used for this connection and set state 3556 if (hci_subevent_le_connection_complete_get_role(packet)){ 3557 // responder - use own address from advertisements 3558 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3559 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3560 } else { 3561 // initiator - use own address from create connection 3562 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3563 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3564 } 3565 break; 3566 3567 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3568 con_handle = little_endian_read_16(packet, 3); 3569 sm_conn = sm_get_connection_for_handle(con_handle); 3570 if (!sm_conn) break; 3571 3572 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3573 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3574 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3575 break; 3576 } 3577 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3578 // PH2 SEND LTK as we need to exchange keys in PH3 3579 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3580 break; 3581 } 3582 3583 // store rand and ediv 3584 reverse_64(&packet[5], sm_conn->sm_local_rand); 3585 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3586 3587 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3588 // potentially stored LTK is from the master 3589 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3590 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3591 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3592 break; 3593 } 3594 // additionally check if remote is in LE Device DB if requested 3595 switch(sm_conn->sm_irk_lookup_state){ 3596 case IRK_LOOKUP_FAILED: 3597 log_info("LTK Request: device not in device db"); 3598 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3599 break; 3600 case IRK_LOOKUP_SUCCEEDED: 3601 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3602 break; 3603 default: 3604 // wait for irk look doen 3605 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3606 break; 3607 } 3608 break; 3609 } 3610 3611 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3612 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3613 #else 3614 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3615 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3616 #endif 3617 break; 3618 3619 default: 3620 break; 3621 } 3622 break; 3623 3624 case HCI_EVENT_ENCRYPTION_CHANGE: 3625 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3626 sm_conn = sm_get_connection_for_handle(con_handle); 3627 if (!sm_conn) break; 3628 3629 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3630 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3631 sm_conn->sm_actual_encryption_key_size); 3632 log_info("event handler, state %u", sm_conn->sm_engine_state); 3633 3634 switch (sm_conn->sm_engine_state){ 3635 3636 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3637 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3638 if (sm_conn->sm_connection_encrypted) { 3639 status = ERROR_CODE_SUCCESS; 3640 if (sm_conn->sm_role){ 3641 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3642 } else { 3643 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3644 } 3645 } else { 3646 status = hci_event_encryption_change_get_status(packet); 3647 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3648 // also, gap_reconnect_security_setup_active will return true 3649 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3650 } 3651 3652 // emit re-encryption complete 3653 sm_reencryption_complete(sm_conn, status); 3654 3655 // notify client, if pairing was requested before 3656 if (sm_conn->sm_pairing_requested){ 3657 sm_conn->sm_pairing_requested = 0; 3658 sm_pairing_complete(sm_conn, status, 0); 3659 } 3660 3661 sm_done_for_handle(sm_conn->sm_handle); 3662 break; 3663 3664 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3665 if (!sm_conn->sm_connection_encrypted) break; 3666 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3667 if (IS_RESPONDER(sm_conn->sm_role)){ 3668 // slave 3669 if (setup->sm_use_secure_connections){ 3670 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3671 } else { 3672 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); 3673 } 3674 } else { 3675 // master 3676 if (sm_key_distribution_all_received(sm_conn)){ 3677 // skip receiving keys as there are none 3678 sm_key_distribution_handle_all_received(sm_conn); 3679 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); 3680 } else { 3681 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3682 } 3683 } 3684 break; 3685 default: 3686 break; 3687 } 3688 break; 3689 3690 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3691 con_handle = little_endian_read_16(packet, 3); 3692 sm_conn = sm_get_connection_for_handle(con_handle); 3693 if (!sm_conn) break; 3694 3695 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3696 log_info("event handler, state %u", sm_conn->sm_engine_state); 3697 // continue if part of initial pairing 3698 switch (sm_conn->sm_engine_state){ 3699 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3700 if (sm_conn->sm_role){ 3701 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3702 } else { 3703 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3704 } 3705 sm_done_for_handle(sm_conn->sm_handle); 3706 break; 3707 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3708 if (IS_RESPONDER(sm_conn->sm_role)){ 3709 // slave 3710 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); 3711 } else { 3712 // master 3713 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3714 } 3715 break; 3716 default: 3717 break; 3718 } 3719 break; 3720 3721 3722 case HCI_EVENT_DISCONNECTION_COMPLETE: 3723 con_handle = little_endian_read_16(packet, 3); 3724 sm_done_for_handle(con_handle); 3725 sm_conn = sm_get_connection_for_handle(con_handle); 3726 if (!sm_conn) break; 3727 3728 // pairing failed, if it was ongoing 3729 switch (sm_conn->sm_engine_state){ 3730 case SM_GENERAL_IDLE: 3731 case SM_INITIATOR_CONNECTED: 3732 case SM_RESPONDER_IDLE: 3733 break; 3734 default: 3735 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3736 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3737 break; 3738 } 3739 3740 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3741 sm_conn->sm_handle = 0; 3742 break; 3743 3744 case HCI_EVENT_COMMAND_COMPLETE: 3745 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3746 // set local addr for le device db 3747 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3748 le_device_db_set_local_bd_addr(addr); 3749 } 3750 break; 3751 default: 3752 break; 3753 } 3754 break; 3755 default: 3756 break; 3757 } 3758 3759 sm_run(); 3760 } 3761 3762 static inline int sm_calc_actual_encryption_key_size(int other){ 3763 if (other < sm_min_encryption_key_size) return 0; 3764 if (other < sm_max_encryption_key_size) return other; 3765 return sm_max_encryption_key_size; 3766 } 3767 3768 3769 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3770 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3771 switch (method){ 3772 case JUST_WORKS: 3773 case NUMERIC_COMPARISON: 3774 return 1; 3775 default: 3776 return 0; 3777 } 3778 } 3779 // responder 3780 3781 static int sm_passkey_used(stk_generation_method_t method){ 3782 switch (method){ 3783 case PK_RESP_INPUT: 3784 return 1; 3785 default: 3786 return 0; 3787 } 3788 } 3789 3790 static int sm_passkey_entry(stk_generation_method_t method){ 3791 switch (method){ 3792 case PK_RESP_INPUT: 3793 case PK_INIT_INPUT: 3794 case PK_BOTH_INPUT: 3795 return 1; 3796 default: 3797 return 0; 3798 } 3799 } 3800 3801 #endif 3802 3803 /** 3804 * @return ok 3805 */ 3806 static int sm_validate_stk_generation_method(void){ 3807 // check if STK generation method is acceptable by client 3808 switch (setup->sm_stk_generation_method){ 3809 case JUST_WORKS: 3810 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3811 case PK_RESP_INPUT: 3812 case PK_INIT_INPUT: 3813 case PK_BOTH_INPUT: 3814 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3815 case OOB: 3816 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3817 case NUMERIC_COMPARISON: 3818 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3819 default: 3820 return 0; 3821 } 3822 } 3823 3824 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3825 3826 // size of complete sm_pdu used to validate input 3827 static const uint8_t sm_pdu_size[] = { 3828 0, // 0x00 invalid opcode 3829 7, // 0x01 pairing request 3830 7, // 0x02 pairing response 3831 17, // 0x03 pairing confirm 3832 17, // 0x04 pairing random 3833 2, // 0x05 pairing failed 3834 17, // 0x06 encryption information 3835 11, // 0x07 master identification 3836 17, // 0x08 identification information 3837 8, // 0x09 identify address information 3838 17, // 0x0a signing information 3839 2, // 0x0b security request 3840 65, // 0x0c pairing public key 3841 17, // 0x0d pairing dhk check 3842 2, // 0x0e keypress notification 3843 }; 3844 3845 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3846 sm_run(); 3847 } 3848 3849 if (packet_type != SM_DATA_PACKET) return; 3850 if (size == 0u) return; 3851 3852 uint8_t sm_pdu_code = packet[0]; 3853 3854 // validate pdu size 3855 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3856 if (sm_pdu_size[sm_pdu_code] != size) return; 3857 3858 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3859 if (!sm_conn) return; 3860 3861 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3862 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 3863 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3864 sm_done_for_handle(con_handle); 3865 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3866 return; 3867 } 3868 3869 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3870 3871 int err; 3872 UNUSED(err); 3873 3874 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3875 uint8_t buffer[5]; 3876 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3877 buffer[1] = 3; 3878 little_endian_store_16(buffer, 2, con_handle); 3879 buffer[4] = packet[1]; 3880 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3881 return; 3882 } 3883 3884 #ifdef ENABLE_LE_CENTRAL 3885 int have_ltk; 3886 uint8_t ltk[16]; 3887 #endif 3888 3889 switch (sm_conn->sm_engine_state){ 3890 3891 // a sm timeout requires a new physical connection 3892 case SM_GENERAL_TIMEOUT: 3893 return; 3894 3895 #ifdef ENABLE_LE_CENTRAL 3896 3897 // Initiator 3898 case SM_INITIATOR_CONNECTED: 3899 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3900 sm_pdu_received_in_wrong_state(sm_conn); 3901 break; 3902 } 3903 3904 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3905 if (sm_sc_only_mode){ 3906 uint8_t auth_req = packet[1]; 3907 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 3908 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 3909 break; 3910 } 3911 } 3912 #endif 3913 3914 // IRK complete? 3915 switch (sm_conn->sm_irk_lookup_state){ 3916 case IRK_LOOKUP_FAILED: 3917 // start pairing 3918 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3919 break; 3920 case IRK_LOOKUP_SUCCEEDED: 3921 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3922 have_ltk = !sm_is_null_key(ltk); 3923 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 3924 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 3925 // start re-encrypt if we have LTK and the connection is not already encrypted 3926 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 3927 } else { 3928 // start pairing 3929 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3930 } 3931 break; 3932 default: 3933 // otherwise, store security request 3934 sm_conn->sm_security_request_received = 1; 3935 break; 3936 } 3937 break; 3938 3939 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3940 // Core 5, Vol 3, Part H, 2.4.6: 3941 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3942 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3943 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3944 log_info("Ignoring Security Request"); 3945 break; 3946 } 3947 3948 // all other pdus are incorrect 3949 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3950 sm_pdu_received_in_wrong_state(sm_conn); 3951 break; 3952 } 3953 3954 // store pairing request 3955 (void)memcpy(&setup->sm_s_pres, packet, 3956 sizeof(sm_pairing_packet_t)); 3957 err = sm_stk_generation_init(sm_conn); 3958 3959 #ifdef ENABLE_TESTING_SUPPORT 3960 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3961 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3962 err = test_pairing_failure; 3963 } 3964 #endif 3965 3966 if (err != 0){ 3967 sm_pairing_error(sm_conn, err); 3968 break; 3969 } 3970 3971 // generate random number first, if we need to show passkey 3972 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3973 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); 3974 break; 3975 } 3976 3977 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3978 if (setup->sm_use_secure_connections){ 3979 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3980 if (setup->sm_stk_generation_method == JUST_WORKS){ 3981 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3982 sm_trigger_user_response(sm_conn); 3983 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3984 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3985 } 3986 } else { 3987 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3988 } 3989 break; 3990 } 3991 #endif 3992 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3993 sm_trigger_user_response(sm_conn); 3994 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3995 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3996 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); 3997 } 3998 break; 3999 4000 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4001 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4002 sm_pdu_received_in_wrong_state(sm_conn); 4003 break; 4004 } 4005 4006 // store s_confirm 4007 reverse_128(&packet[1], setup->sm_peer_confirm); 4008 4009 // abort if s_confirm matches m_confirm 4010 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4011 sm_pdu_received_in_wrong_state(sm_conn); 4012 break; 4013 } 4014 4015 #ifdef ENABLE_TESTING_SUPPORT 4016 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4017 log_info("testing_support: reset confirm value"); 4018 memset(setup->sm_peer_confirm, 0, 16); 4019 } 4020 #endif 4021 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4022 break; 4023 4024 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4025 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4026 sm_pdu_received_in_wrong_state(sm_conn); 4027 break;; 4028 } 4029 4030 // received random value 4031 reverse_128(&packet[1], setup->sm_peer_random); 4032 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4033 break; 4034 #endif 4035 4036 #ifdef ENABLE_LE_PERIPHERAL 4037 // Responder 4038 case SM_RESPONDER_IDLE: 4039 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4040 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4041 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4042 sm_pdu_received_in_wrong_state(sm_conn); 4043 break;; 4044 } 4045 4046 // store pairing request 4047 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4048 4049 // check if IRK completed 4050 switch (sm_conn->sm_irk_lookup_state){ 4051 case IRK_LOOKUP_SUCCEEDED: 4052 case IRK_LOOKUP_FAILED: 4053 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4054 break; 4055 default: 4056 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4057 break; 4058 } 4059 break; 4060 #endif 4061 4062 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4063 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4064 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4065 sm_pdu_received_in_wrong_state(sm_conn); 4066 break; 4067 } 4068 4069 // store public key for DH Key calculation 4070 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4071 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4072 4073 // CVE-2020-26558: abort pairing if remote uses the same public key 4074 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4075 log_info("Remote PK matches ours"); 4076 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4077 break; 4078 } 4079 4080 // validate public key 4081 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4082 if (err != 0){ 4083 log_info("sm: peer public key invalid %x", err); 4084 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4085 break; 4086 } 4087 4088 // start calculating dhkey 4089 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); 4090 4091 4092 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4093 if (IS_RESPONDER(sm_conn->sm_role)){ 4094 // responder 4095 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4096 } else { 4097 // initiator 4098 // stk generation method 4099 // passkey entry: notify app to show passkey or to request passkey 4100 switch (setup->sm_stk_generation_method){ 4101 case JUST_WORKS: 4102 case NUMERIC_COMPARISON: 4103 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4104 break; 4105 case PK_RESP_INPUT: 4106 sm_sc_start_calculating_local_confirm(sm_conn); 4107 break; 4108 case PK_INIT_INPUT: 4109 case PK_BOTH_INPUT: 4110 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4111 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4112 break; 4113 } 4114 sm_sc_start_calculating_local_confirm(sm_conn); 4115 break; 4116 case OOB: 4117 // generate Nx 4118 log_info("Generate Na"); 4119 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); 4120 break; 4121 default: 4122 btstack_assert(false); 4123 break; 4124 } 4125 } 4126 break; 4127 4128 case SM_SC_W4_CONFIRMATION: 4129 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4130 sm_pdu_received_in_wrong_state(sm_conn); 4131 break; 4132 } 4133 // received confirm value 4134 reverse_128(&packet[1], setup->sm_peer_confirm); 4135 4136 #ifdef ENABLE_TESTING_SUPPORT 4137 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4138 log_info("testing_support: reset confirm value"); 4139 memset(setup->sm_peer_confirm, 0, 16); 4140 } 4141 #endif 4142 if (IS_RESPONDER(sm_conn->sm_role)){ 4143 // responder 4144 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4145 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4146 // still waiting for passkey 4147 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4148 break; 4149 } 4150 } 4151 sm_sc_start_calculating_local_confirm(sm_conn); 4152 } else { 4153 // initiator 4154 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4155 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); 4156 } else { 4157 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4158 } 4159 } 4160 break; 4161 4162 case SM_SC_W4_PAIRING_RANDOM: 4163 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4164 sm_pdu_received_in_wrong_state(sm_conn); 4165 break; 4166 } 4167 4168 // received random value 4169 reverse_128(&packet[1], setup->sm_peer_nonce); 4170 4171 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4172 // only check for JUST WORK/NC in initiator role OR passkey entry 4173 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4174 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4175 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4176 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4177 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4178 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4179 break; 4180 } 4181 4182 // OOB 4183 if (setup->sm_stk_generation_method == OOB){ 4184 4185 // setup local random, set to zero if remote did not receive our data 4186 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4187 if (IS_RESPONDER(sm_conn->sm_role)){ 4188 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4189 log_info("Reset rb as A does not have OOB data"); 4190 memset(setup->sm_rb, 0, 16); 4191 } else { 4192 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4193 log_info("Use stored rb"); 4194 log_info_hexdump(setup->sm_rb, 16); 4195 } 4196 } else { 4197 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4198 log_info("Reset ra as B does not have OOB data"); 4199 memset(setup->sm_ra, 0, 16); 4200 } else { 4201 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4202 log_info("Use stored ra"); 4203 log_info_hexdump(setup->sm_ra, 16); 4204 } 4205 } 4206 4207 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4208 if (setup->sm_have_oob_data){ 4209 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4210 break; 4211 } 4212 } 4213 4214 // TODO: we only get here for Responder role with JW/NC 4215 sm_sc_state_after_receiving_random(sm_conn); 4216 break; 4217 4218 case SM_SC_W2_CALCULATE_G2: 4219 case SM_SC_W4_CALCULATE_G2: 4220 case SM_SC_W4_CALCULATE_DHKEY: 4221 case SM_SC_W2_CALCULATE_F5_SALT: 4222 case SM_SC_W4_CALCULATE_F5_SALT: 4223 case SM_SC_W2_CALCULATE_F5_MACKEY: 4224 case SM_SC_W4_CALCULATE_F5_MACKEY: 4225 case SM_SC_W2_CALCULATE_F5_LTK: 4226 case SM_SC_W4_CALCULATE_F5_LTK: 4227 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4228 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4229 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4230 case SM_SC_W4_USER_RESPONSE: 4231 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4232 sm_pdu_received_in_wrong_state(sm_conn); 4233 break; 4234 } 4235 // store DHKey Check 4236 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4237 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4238 4239 // have we been only waiting for dhkey check command? 4240 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4241 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4242 } 4243 break; 4244 #endif 4245 4246 #ifdef ENABLE_LE_PERIPHERAL 4247 case SM_RESPONDER_PH1_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 // received confirm value 4254 reverse_128(&packet[1], setup->sm_peer_confirm); 4255 4256 #ifdef ENABLE_TESTING_SUPPORT 4257 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4258 log_info("testing_support: reset confirm value"); 4259 memset(setup->sm_peer_confirm, 0, 16); 4260 } 4261 #endif 4262 // notify client to hide shown passkey 4263 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4264 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4265 } 4266 4267 // handle user cancel pairing? 4268 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4269 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4270 break; 4271 } 4272 4273 // wait for user action? 4274 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4275 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4276 break; 4277 } 4278 4279 // calculate and send local_confirm 4280 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); 4281 break; 4282 4283 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4284 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4285 sm_pdu_received_in_wrong_state(sm_conn); 4286 break;; 4287 } 4288 4289 // received random value 4290 reverse_128(&packet[1], setup->sm_peer_random); 4291 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4292 break; 4293 #endif 4294 4295 case SM_PH3_RECEIVE_KEYS: 4296 switch(sm_pdu_code){ 4297 case SM_CODE_ENCRYPTION_INFORMATION: 4298 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4299 reverse_128(&packet[1], setup->sm_peer_ltk); 4300 break; 4301 4302 case SM_CODE_MASTER_IDENTIFICATION: 4303 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4304 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4305 reverse_64(&packet[3], setup->sm_peer_rand); 4306 break; 4307 4308 case SM_CODE_IDENTITY_INFORMATION: 4309 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4310 reverse_128(&packet[1], setup->sm_peer_irk); 4311 break; 4312 4313 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4314 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4315 setup->sm_peer_addr_type = packet[1]; 4316 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4317 break; 4318 4319 case SM_CODE_SIGNING_INFORMATION: 4320 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4321 reverse_128(&packet[1], setup->sm_peer_csrk); 4322 break; 4323 default: 4324 // Unexpected PDU 4325 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4326 break; 4327 } 4328 // done with key distribution? 4329 if (sm_key_distribution_all_received(sm_conn)){ 4330 4331 sm_key_distribution_handle_all_received(sm_conn); 4332 4333 if (IS_RESPONDER(sm_conn->sm_role)){ 4334 sm_key_distribution_complete_responder(sm_conn); 4335 } else { 4336 if (setup->sm_use_secure_connections){ 4337 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4338 } else { 4339 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); 4340 } 4341 } 4342 } 4343 break; 4344 default: 4345 // Unexpected PDU 4346 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4347 sm_pdu_received_in_wrong_state(sm_conn); 4348 break; 4349 } 4350 4351 // try to send next pdu 4352 sm_trigger_run(); 4353 } 4354 4355 // Security Manager Client API 4356 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4357 sm_get_oob_data = get_oob_data_callback; 4358 } 4359 4360 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)){ 4361 sm_get_sc_oob_data = get_sc_oob_data_callback; 4362 } 4363 4364 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4365 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4366 } 4367 4368 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4369 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4370 } 4371 4372 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4373 sm_min_encryption_key_size = min_size; 4374 sm_max_encryption_key_size = max_size; 4375 } 4376 4377 void sm_set_authentication_requirements(uint8_t auth_req){ 4378 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4379 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4380 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4381 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4382 } 4383 #endif 4384 sm_auth_req = auth_req; 4385 } 4386 4387 void sm_set_io_capabilities(io_capability_t io_capability){ 4388 sm_io_capabilities = io_capability; 4389 } 4390 4391 #ifdef ENABLE_LE_PERIPHERAL 4392 void sm_set_request_security(int enable){ 4393 sm_slave_request_security = enable; 4394 } 4395 #endif 4396 4397 void sm_set_er(sm_key_t er){ 4398 (void)memcpy(sm_persistent_er, er, 16); 4399 } 4400 4401 void sm_set_ir(sm_key_t ir){ 4402 (void)memcpy(sm_persistent_ir, ir, 16); 4403 } 4404 4405 // Testing support only 4406 void sm_test_set_irk(sm_key_t irk){ 4407 (void)memcpy(sm_persistent_irk, irk, 16); 4408 dkg_state = DKG_CALC_DHK; 4409 test_use_fixed_local_irk = true; 4410 } 4411 4412 void sm_test_use_fixed_local_csrk(void){ 4413 test_use_fixed_local_csrk = true; 4414 } 4415 4416 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4417 static void sm_ec_generated(void * arg){ 4418 UNUSED(arg); 4419 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4420 // trigger pairing if pending for ec key 4421 sm_trigger_run(); 4422 } 4423 static void sm_ec_generate_new_key(void){ 4424 log_info("sm: generate new ec key"); 4425 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4426 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4427 } 4428 #endif 4429 4430 #ifdef ENABLE_TESTING_SUPPORT 4431 void sm_test_set_pairing_failure(int reason){ 4432 test_pairing_failure = reason; 4433 } 4434 #endif 4435 4436 void sm_init(void){ 4437 4438 if (sm_initialized) return; 4439 4440 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4441 sm_er_ir_set_default(); 4442 4443 // defaults 4444 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4445 | SM_STK_GENERATION_METHOD_OOB 4446 | SM_STK_GENERATION_METHOD_PASSKEY 4447 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4448 4449 sm_max_encryption_key_size = 16; 4450 sm_min_encryption_key_size = 7; 4451 4452 sm_fixed_passkey_in_display_role = 0xffffffffU; 4453 sm_reconstruct_ltk_without_le_device_db_entry = true; 4454 4455 #ifdef USE_CMAC_ENGINE 4456 sm_cmac_active = 0; 4457 #endif 4458 dkg_state = DKG_W4_WORKING; 4459 rau_state = RAU_IDLE; 4460 sm_aes128_state = SM_AES128_IDLE; 4461 sm_address_resolution_test = -1; // no private address to resolve yet 4462 sm_address_resolution_ah_calculation_active = 0; 4463 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4464 sm_address_resolution_general_queue = NULL; 4465 4466 gap_random_adress_update_period = 15 * 60 * 1000L; 4467 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4468 4469 test_use_fixed_local_csrk = false; 4470 4471 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4472 4473 // register for HCI Events from HCI 4474 hci_event_callback_registration.callback = &sm_event_packet_handler; 4475 hci_add_event_handler(&hci_event_callback_registration); 4476 4477 // 4478 btstack_crypto_init(); 4479 4480 // init le_device_db 4481 le_device_db_init(); 4482 4483 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4484 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4485 4486 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4487 sm_ec_generate_new_key(); 4488 #endif 4489 4490 sm_initialized = true; 4491 } 4492 4493 void sm_deinit(void){ 4494 sm_initialized = false; 4495 btstack_run_loop_remove_timer(&sm_run_timer); 4496 } 4497 4498 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4499 sm_fixed_passkey_in_display_role = passkey; 4500 } 4501 4502 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4503 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4504 } 4505 4506 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4507 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4508 if (!hci_con) return NULL; 4509 return &hci_con->sm_connection; 4510 } 4511 4512 // @deprecated: map onto sm_request_pairing 4513 void sm_send_security_request(hci_con_handle_t con_handle){ 4514 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4515 if (!sm_conn) return; 4516 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4517 sm_request_pairing(con_handle); 4518 } 4519 4520 // request pairing 4521 void sm_request_pairing(hci_con_handle_t con_handle){ 4522 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4523 if (!sm_conn) return; // wrong connection 4524 4525 bool have_ltk; 4526 uint8_t ltk[16]; 4527 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4528 if (IS_RESPONDER(sm_conn->sm_role)){ 4529 switch (sm_conn->sm_engine_state){ 4530 case SM_GENERAL_IDLE: 4531 case SM_RESPONDER_IDLE: 4532 switch (sm_conn->sm_irk_lookup_state){ 4533 case IRK_LOOKUP_SUCCEEDED: 4534 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4535 have_ltk = !sm_is_null_key(ltk); 4536 log_info("have ltk %u", have_ltk); 4537 if (have_ltk){ 4538 sm_conn->sm_pairing_requested = 1; 4539 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4540 sm_reencryption_started(sm_conn); 4541 break; 4542 } 4543 /* fall through */ 4544 4545 case IRK_LOOKUP_FAILED: 4546 sm_conn->sm_pairing_requested = 1; 4547 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4548 sm_pairing_started(sm_conn); 4549 break; 4550 default: 4551 log_info("irk lookup pending"); 4552 sm_conn->sm_pairing_requested = 1; 4553 break; 4554 } 4555 break; 4556 default: 4557 break; 4558 } 4559 } else { 4560 // used as a trigger to start central/master/initiator security procedures 4561 switch (sm_conn->sm_engine_state){ 4562 case SM_INITIATOR_CONNECTED: 4563 switch (sm_conn->sm_irk_lookup_state){ 4564 case IRK_LOOKUP_SUCCEEDED: 4565 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4566 have_ltk = !sm_is_null_key(ltk); 4567 log_info("have ltk %u", have_ltk); 4568 if (have_ltk){ 4569 sm_conn->sm_pairing_requested = 1; 4570 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4571 break; 4572 } 4573 /* fall through */ 4574 4575 case IRK_LOOKUP_FAILED: 4576 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4577 break; 4578 default: 4579 log_info("irk lookup pending"); 4580 sm_conn->sm_pairing_requested = 1; 4581 break; 4582 } 4583 break; 4584 case SM_GENERAL_REENCRYPTION_FAILED: 4585 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4586 break; 4587 case SM_GENERAL_IDLE: 4588 sm_conn->sm_pairing_requested = 1; 4589 break; 4590 default: 4591 break; 4592 } 4593 } 4594 sm_trigger_run(); 4595 } 4596 4597 // called by client app on authorization request 4598 void sm_authorization_decline(hci_con_handle_t con_handle){ 4599 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4600 if (!sm_conn) return; // wrong connection 4601 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4602 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4603 } 4604 4605 void sm_authorization_grant(hci_con_handle_t con_handle){ 4606 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4607 if (!sm_conn) return; // wrong connection 4608 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4609 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4610 } 4611 4612 // GAP Bonding API 4613 4614 void sm_bonding_decline(hci_con_handle_t con_handle){ 4615 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4616 if (!sm_conn) return; // wrong connection 4617 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4618 log_info("decline, state %u", sm_conn->sm_engine_state); 4619 switch(sm_conn->sm_engine_state){ 4620 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4621 case SM_SC_W4_USER_RESPONSE: 4622 case SM_SC_W4_CONFIRMATION: 4623 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4624 #endif 4625 case SM_PH1_W4_USER_RESPONSE: 4626 switch (setup->sm_stk_generation_method){ 4627 case PK_RESP_INPUT: 4628 case PK_INIT_INPUT: 4629 case PK_BOTH_INPUT: 4630 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4631 break; 4632 case NUMERIC_COMPARISON: 4633 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4634 break; 4635 case JUST_WORKS: 4636 case OOB: 4637 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4638 break; 4639 default: 4640 btstack_assert(false); 4641 break; 4642 } 4643 break; 4644 default: 4645 break; 4646 } 4647 sm_trigger_run(); 4648 } 4649 4650 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4651 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4652 if (!sm_conn) return; // wrong connection 4653 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4654 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4655 if (setup->sm_use_secure_connections){ 4656 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4657 } else { 4658 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); 4659 } 4660 } 4661 4662 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4663 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4664 sm_sc_prepare_dhkey_check(sm_conn); 4665 } 4666 #endif 4667 4668 sm_trigger_run(); 4669 } 4670 4671 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4672 // for now, it's the same 4673 sm_just_works_confirm(con_handle); 4674 } 4675 4676 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4677 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4678 if (!sm_conn) return; // wrong connection 4679 sm_reset_tk(); 4680 big_endian_store_32(setup->sm_tk, 12, passkey); 4681 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4682 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4683 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); 4684 } 4685 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4686 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4687 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4688 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4689 sm_sc_start_calculating_local_confirm(sm_conn); 4690 } 4691 #endif 4692 sm_trigger_run(); 4693 } 4694 4695 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4696 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4697 if (!sm_conn) return; // wrong connection 4698 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4699 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4700 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4701 switch (action){ 4702 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4703 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4704 flags |= (1u << action); 4705 break; 4706 case SM_KEYPRESS_PASSKEY_CLEARED: 4707 // clear counter, keypress & erased flags + set passkey cleared 4708 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4709 break; 4710 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4711 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4712 // erase actions queued 4713 num_actions--; 4714 if (num_actions == 0u){ 4715 // clear counter, keypress & erased flags 4716 flags &= 0x19u; 4717 } 4718 break; 4719 } 4720 num_actions++; 4721 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4722 break; 4723 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4724 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4725 // enter actions queued 4726 num_actions--; 4727 if (num_actions == 0u){ 4728 // clear counter, keypress & erased flags 4729 flags &= 0x19u; 4730 } 4731 break; 4732 } 4733 num_actions++; 4734 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4735 break; 4736 default: 4737 break; 4738 } 4739 setup->sm_keypress_notification = (num_actions << 5) | flags; 4740 sm_trigger_run(); 4741 } 4742 4743 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4744 static void sm_handle_random_result_oob(void * arg){ 4745 UNUSED(arg); 4746 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4747 sm_trigger_run(); 4748 } 4749 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4750 4751 static btstack_crypto_random_t sm_crypto_random_oob_request; 4752 4753 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4754 sm_sc_oob_callback = callback; 4755 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4756 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4757 return 0; 4758 } 4759 #endif 4760 4761 /** 4762 * @brief Get Identity Resolving state 4763 * @param con_handle 4764 * @return irk_lookup_state_t 4765 */ 4766 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4767 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4768 if (!sm_conn) return IRK_LOOKUP_IDLE; 4769 return sm_conn->sm_irk_lookup_state; 4770 } 4771 4772 /** 4773 * @brief Identify device in LE Device DB 4774 * @param handle 4775 * @returns index from le_device_db or -1 if not found/identified 4776 */ 4777 int sm_le_device_index(hci_con_handle_t con_handle ){ 4778 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4779 if (!sm_conn) return -1; 4780 return sm_conn->sm_le_db_index; 4781 } 4782 4783 static int gap_random_address_type_requires_updates(void){ 4784 switch (gap_random_adress_type){ 4785 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4786 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4787 return 0; 4788 default: 4789 return 1; 4790 } 4791 } 4792 4793 static uint8_t own_address_type(void){ 4794 switch (gap_random_adress_type){ 4795 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4796 return BD_ADDR_TYPE_LE_PUBLIC; 4797 default: 4798 return BD_ADDR_TYPE_LE_RANDOM; 4799 } 4800 } 4801 4802 // GAP LE API 4803 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4804 gap_random_address_update_stop(); 4805 gap_random_adress_type = random_address_type; 4806 hci_le_set_own_address_type(own_address_type()); 4807 if (!gap_random_address_type_requires_updates()) return; 4808 gap_random_address_update_start(); 4809 gap_random_address_trigger(); 4810 } 4811 4812 gap_random_address_type_t gap_random_address_get_mode(void){ 4813 return gap_random_adress_type; 4814 } 4815 4816 void gap_random_address_set_update_period(int period_ms){ 4817 gap_random_adress_update_period = period_ms; 4818 if (!gap_random_address_type_requires_updates()) return; 4819 gap_random_address_update_stop(); 4820 gap_random_address_update_start(); 4821 } 4822 4823 void gap_random_address_set(const bd_addr_t addr){ 4824 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4825 (void)memcpy(sm_random_address, addr, 6); 4826 rau_state = RAU_SET_ADDRESS; 4827 sm_trigger_run(); 4828 } 4829 4830 #ifdef ENABLE_LE_PERIPHERAL 4831 /* 4832 * @brief Set Advertisement Paramters 4833 * @param adv_int_min 4834 * @param adv_int_max 4835 * @param adv_type 4836 * @param direct_address_type 4837 * @param direct_address 4838 * @param channel_map 4839 * @param filter_policy 4840 * 4841 * @note own_address_type is used from gap_random_address_set_mode 4842 */ 4843 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4844 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4845 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4846 direct_address_typ, direct_address, channel_map, filter_policy); 4847 } 4848 #endif 4849 4850 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4851 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4852 // wrong connection 4853 if (!sm_conn) return 0; 4854 // already encrypted 4855 if (sm_conn->sm_connection_encrypted) return 0; 4856 // irk status? 4857 switch(sm_conn->sm_irk_lookup_state){ 4858 case IRK_LOOKUP_FAILED: 4859 // done, cannot setup encryption 4860 return 0; 4861 case IRK_LOOKUP_SUCCEEDED: 4862 break; 4863 default: 4864 // IR Lookup pending 4865 return 1; 4866 } 4867 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 4868 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 4869 if (sm_conn->sm_role){ 4870 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 4871 } else { 4872 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4873 } 4874 } 4875 4876 void sm_set_secure_connections_only_mode(bool enable){ 4877 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4878 sm_sc_only_mode = enable; 4879 #else 4880 // SC Only mode not possible without support for SC 4881 btstack_assert(enable == false); 4882 #endif 4883 } 4884 4885 const uint8_t * gap_get_persistent_irk(void){ 4886 return sm_persistent_irk; 4887 } 4888 4889 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 4890 uint16_t i; 4891 for (i=0; i < le_device_db_max_count(); i++){ 4892 bd_addr_t entry_address; 4893 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 4894 le_device_db_info(i, &entry_address_type, entry_address, NULL); 4895 // skip unused entries 4896 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 4897 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 4898 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 4899 hci_remove_le_device_db_entry_from_resolving_list(i); 4900 #endif 4901 le_device_db_remove(i); 4902 break; 4903 } 4904 } 4905 } 4906