1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 } random_address_update_t; 111 112 typedef enum { 113 CMAC_IDLE, 114 CMAC_CALC_SUBKEYS, 115 CMAC_W4_SUBKEYS, 116 CMAC_CALC_MI, 117 CMAC_W4_MI, 118 CMAC_CALC_MLAST, 119 CMAC_W4_MLAST 120 } cmac_state_t; 121 122 typedef enum { 123 JUST_WORKS, 124 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 125 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 126 PK_BOTH_INPUT, // Only input on both, both input PK 127 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 128 OOB // OOB available on one (SC) or both sides (legacy) 129 } stk_generation_method_t; 130 131 typedef enum { 132 SM_USER_RESPONSE_IDLE, 133 SM_USER_RESPONSE_PENDING, 134 SM_USER_RESPONSE_CONFIRM, 135 SM_USER_RESPONSE_PASSKEY, 136 SM_USER_RESPONSE_DECLINE 137 } sm_user_response_t; 138 139 typedef enum { 140 SM_AES128_IDLE, 141 SM_AES128_ACTIVE 142 } sm_aes128_state_t; 143 144 typedef enum { 145 ADDRESS_RESOLUTION_IDLE, 146 ADDRESS_RESOLUTION_GENERAL, 147 ADDRESS_RESOLUTION_FOR_CONNECTION, 148 } address_resolution_mode_t; 149 150 typedef enum { 151 ADDRESS_RESOLUTION_SUCCEEDED, 152 ADDRESS_RESOLUTION_FAILED, 153 } address_resolution_event_t; 154 155 typedef enum { 156 EC_KEY_GENERATION_IDLE, 157 EC_KEY_GENERATION_ACTIVE, 158 EC_KEY_GENERATION_DONE, 159 } ec_key_generation_state_t; 160 161 typedef enum { 162 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 163 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 165 } sm_state_var_t; 166 167 typedef enum { 168 SM_SC_OOB_IDLE, 169 SM_SC_OOB_W4_RANDOM, 170 SM_SC_OOB_W2_CALC_CONFIRM, 171 SM_SC_OOB_W4_CONFIRM, 172 } sm_sc_oob_state_t; 173 174 typedef uint8_t sm_key24_t[3]; 175 typedef uint8_t sm_key56_t[7]; 176 typedef uint8_t sm_key256_t[32]; 177 178 // 179 // GLOBAL DATA 180 // 181 182 static bool sm_initialized; 183 184 static bool test_use_fixed_local_csrk; 185 static bool test_use_fixed_local_irk; 186 187 #ifdef ENABLE_TESTING_SUPPORT 188 static uint8_t test_pairing_failure; 189 #endif 190 191 // configuration 192 static uint8_t sm_accepted_stk_generation_methods; 193 static uint8_t sm_max_encryption_key_size; 194 static uint8_t sm_min_encryption_key_size; 195 static uint8_t sm_auth_req = 0; 196 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static bool sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_PERIPHERAL 201 static uint8_t sm_slave_request_security; 202 #endif 203 204 #ifdef ENABLE_LE_SECURE_CONNECTIONS 205 static bool sm_sc_only_mode; 206 static uint8_t sm_sc_oob_random[16]; 207 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 208 static sm_sc_oob_state_t sm_sc_oob_state; 209 #endif 210 211 212 static bool sm_persistent_keys_random_active; 213 static const btstack_tlv_t * sm_tlv_impl; 214 static void * sm_tlv_context; 215 216 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 217 static sm_key_t sm_persistent_er; 218 static sm_key_t sm_persistent_ir; 219 220 // derived from sm_persistent_ir 221 static sm_key_t sm_persistent_dhk; 222 static sm_key_t sm_persistent_irk; 223 static derived_key_generation_t dkg_state; 224 225 // derived from sm_persistent_er 226 // .. 227 228 // random address update 229 static random_address_update_t rau_state; 230 static bd_addr_t sm_random_address; 231 232 #ifdef USE_CMAC_ENGINE 233 // CMAC Calculation: General 234 static btstack_crypto_aes128_cmac_t sm_cmac_request; 235 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 236 static uint8_t sm_cmac_active; 237 static uint8_t sm_cmac_hash[16]; 238 #endif 239 240 // CMAC for ATT Signed Writes 241 #ifdef ENABLE_LE_SIGNED_WRITE 242 static uint16_t sm_cmac_signed_write_message_len; 243 static uint8_t sm_cmac_signed_write_header[3]; 244 static const uint8_t * sm_cmac_signed_write_message; 245 static uint8_t sm_cmac_signed_write_sign_counter[4]; 246 #endif 247 248 // CMAC for Secure Connection functions 249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 250 static sm_connection_t * sm_cmac_connection; 251 static uint8_t sm_cmac_sc_buffer[80]; 252 #endif 253 254 // resolvable private address lookup / CSRK calculation 255 static int sm_address_resolution_test; 256 static int sm_address_resolution_ah_calculation_active; 257 static uint8_t sm_address_resolution_addr_type; 258 static bd_addr_t sm_address_resolution_address; 259 static void * sm_address_resolution_context; 260 static address_resolution_mode_t sm_address_resolution_mode; 261 static btstack_linked_list_t sm_address_resolution_general_queue; 262 263 // aes128 crypto engine. 264 static sm_aes128_state_t sm_aes128_state; 265 266 // crypto 267 static btstack_crypto_random_t sm_crypto_random_request; 268 static btstack_crypto_aes128_t sm_crypto_aes128_request; 269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 270 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 271 #endif 272 273 // temp storage for random data 274 static uint8_t sm_random_data[8]; 275 static uint8_t sm_aes128_key[16]; 276 static uint8_t sm_aes128_plaintext[16]; 277 static uint8_t sm_aes128_ciphertext[16]; 278 279 // to receive hci events 280 static btstack_packet_callback_registration_t hci_event_callback_registration; 281 282 /* to dispatch sm event */ 283 static btstack_linked_list_t sm_event_handlers; 284 285 /* to schedule calls to sm_run */ 286 static btstack_timer_source_t sm_run_timer; 287 288 // LE Secure Connections 289 #ifdef ENABLE_LE_SECURE_CONNECTIONS 290 static ec_key_generation_state_t ec_key_generation_state; 291 static uint8_t ec_q[64]; 292 #endif 293 294 // 295 // Volume 3, Part H, Chapter 24 296 // "Security shall be initiated by the Security Manager in the device in the master role. 297 // The device in the slave role shall be the responding device." 298 // -> master := initiator, slave := responder 299 // 300 301 // data needed for security setup 302 typedef struct sm_setup_context { 303 304 btstack_timer_source_t sm_timeout; 305 306 // user response, (Phase 1 and/or 2) 307 uint8_t sm_user_response; 308 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 309 310 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 311 uint8_t sm_key_distribution_send_set; 312 uint8_t sm_key_distribution_sent_set; 313 uint8_t sm_key_distribution_expected_set; 314 uint8_t sm_key_distribution_received_set; 315 316 // Phase 2 (Pairing over SMP) 317 stk_generation_method_t sm_stk_generation_method; 318 sm_key_t sm_tk; 319 uint8_t sm_have_oob_data; 320 uint8_t sm_use_secure_connections; 321 322 sm_key_t sm_c1_t3_value; // c1 calculation 323 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 324 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 325 sm_key_t sm_local_random; 326 sm_key_t sm_local_confirm; 327 sm_key_t sm_peer_random; 328 sm_key_t sm_peer_confirm; 329 uint8_t sm_m_addr_type; // address and type can be removed 330 uint8_t sm_s_addr_type; // '' 331 bd_addr_t sm_m_address; // '' 332 bd_addr_t sm_s_address; // '' 333 sm_key_t sm_ltk; 334 335 uint8_t sm_state_vars; 336 #ifdef ENABLE_LE_SECURE_CONNECTIONS 337 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 338 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 339 sm_key_t sm_local_nonce; // might be combined with sm_local_random 340 uint8_t sm_dhkey[32]; 341 sm_key_t sm_peer_dhkey_check; 342 sm_key_t sm_local_dhkey_check; 343 sm_key_t sm_ra; 344 sm_key_t sm_rb; 345 sm_key_t sm_t; // used for f5 and h6 346 sm_key_t sm_mackey; 347 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 348 #endif 349 350 // Phase 3 351 352 // key distribution, we generate 353 uint16_t sm_local_y; 354 uint16_t sm_local_div; 355 uint16_t sm_local_ediv; 356 uint8_t sm_local_rand[8]; 357 sm_key_t sm_local_ltk; 358 sm_key_t sm_local_csrk; 359 sm_key_t sm_local_irk; 360 // sm_local_address/addr_type not needed 361 362 // key distribution, received from peer 363 uint16_t sm_peer_y; 364 uint16_t sm_peer_div; 365 uint16_t sm_peer_ediv; 366 uint8_t sm_peer_rand[8]; 367 sm_key_t sm_peer_ltk; 368 sm_key_t sm_peer_irk; 369 sm_key_t sm_peer_csrk; 370 uint8_t sm_peer_addr_type; 371 bd_addr_t sm_peer_address; 372 #ifdef ENABLE_LE_SIGNED_WRITE 373 int sm_le_device_index; 374 #endif 375 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 376 link_key_t sm_link_key; 377 link_key_type_t sm_link_key_type; 378 #endif 379 } sm_setup_context_t; 380 381 // 382 static sm_setup_context_t the_setup; 383 static sm_setup_context_t * setup = &the_setup; 384 385 // active connection - the one for which the_setup is used for 386 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 387 388 // @return 1 if oob data is available 389 // stores oob data in provided 16 byte buffer if not null 390 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 391 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 392 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 393 394 static void sm_run(void); 395 static void sm_state_reset(void); 396 static void sm_done_for_handle(hci_con_handle_t con_handle); 397 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 398 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 399 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 400 #endif 401 static inline int sm_calc_actual_encryption_key_size(int other); 402 static int sm_validate_stk_generation_method(void); 403 static void sm_handle_encryption_result_address_resolution(void *arg); 404 static void sm_handle_encryption_result_dkg_dhk(void *arg); 405 static void sm_handle_encryption_result_dkg_irk(void *arg); 406 static void sm_handle_encryption_result_enc_a(void *arg); 407 static void sm_handle_encryption_result_enc_b(void *arg); 408 static void sm_handle_encryption_result_enc_c(void *arg); 409 static void sm_handle_encryption_result_enc_csrk(void *arg); 410 static void sm_handle_encryption_result_enc_d(void * arg); 411 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 412 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 413 #ifdef ENABLE_LE_PERIPHERAL 414 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 415 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 416 #endif 417 static void sm_handle_encryption_result_enc_stk(void *arg); 418 static void sm_handle_encryption_result_rau(void *arg); 419 static void sm_handle_random_result_ph2_tk(void * arg); 420 static void sm_handle_random_result_rau(void * arg); 421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 422 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 423 static void sm_ec_generate_new_key(void); 424 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 425 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 426 static int sm_passkey_entry(stk_generation_method_t method); 427 #endif 428 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 429 430 static void log_info_hex16(const char * name, uint16_t value){ 431 log_info("%-6s 0x%04x", name, value); 432 } 433 434 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 435 // return packet[0]; 436 // } 437 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 438 return packet[1]; 439 } 440 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 441 return packet[2]; 442 } 443 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 444 return packet[3]; 445 } 446 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 447 return packet[4]; 448 } 449 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 450 return packet[5]; 451 } 452 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 453 return packet[6]; 454 } 455 456 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 457 packet[0] = code; 458 } 459 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 460 packet[1] = io_capability; 461 } 462 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 463 packet[2] = oob_data_flag; 464 } 465 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 466 packet[3] = auth_req; 467 } 468 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 469 packet[4] = max_encryption_key_size; 470 } 471 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 472 packet[5] = initiator_key_distribution; 473 } 474 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 475 packet[6] = responder_key_distribution; 476 } 477 478 // @return 1 if all bytes are 0 479 static bool sm_is_null(uint8_t * data, int size){ 480 int i; 481 for (i=0; i < size ; i++){ 482 if (data[i] != 0) { 483 return false; 484 } 485 } 486 return true; 487 } 488 489 static bool sm_is_null_random(uint8_t random[8]){ 490 return sm_is_null(random, 8); 491 } 492 493 static bool sm_is_null_key(uint8_t * key){ 494 return sm_is_null(key, 16); 495 } 496 497 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 498 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 499 UNUSED(ts); 500 sm_run(); 501 } 502 static void sm_trigger_run(void){ 503 if (!sm_initialized) return; 504 (void)btstack_run_loop_remove_timer(&sm_run_timer); 505 btstack_run_loop_set_timer(&sm_run_timer, 0); 506 btstack_run_loop_add_timer(&sm_run_timer); 507 } 508 509 // Key utils 510 static void sm_reset_tk(void){ 511 int i; 512 for (i=0;i<16;i++){ 513 setup->sm_tk[i] = 0; 514 } 515 } 516 517 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 518 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 519 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 520 int i; 521 for (i = max_encryption_size ; i < 16 ; i++){ 522 key[15-i] = 0; 523 } 524 } 525 526 // ER / IR checks 527 static void sm_er_ir_set_default(void){ 528 int i; 529 for (i=0;i<16;i++){ 530 sm_persistent_er[i] = 0x30 + i; 531 sm_persistent_ir[i] = 0x90 + i; 532 } 533 } 534 535 static int sm_er_is_default(void){ 536 int i; 537 for (i=0;i<16;i++){ 538 if (sm_persistent_er[i] != (0x30+i)) return 0; 539 } 540 return 1; 541 } 542 543 static int sm_ir_is_default(void){ 544 int i; 545 for (i=0;i<16;i++){ 546 if (sm_persistent_ir[i] != (0x90+i)) return 0; 547 } 548 return 1; 549 } 550 551 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 552 UNUSED(channel); 553 554 // log event 555 hci_dump_packet(packet_type, 1, packet, size); 556 // dispatch to all event handlers 557 btstack_linked_list_iterator_t it; 558 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 559 while (btstack_linked_list_iterator_has_next(&it)){ 560 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 561 entry->callback(packet_type, 0, packet, size); 562 } 563 } 564 565 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 566 event[0] = type; 567 event[1] = event_size - 2; 568 little_endian_store_16(event, 2, con_handle); 569 event[4] = addr_type; 570 reverse_bd_addr(address, &event[5]); 571 } 572 573 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 574 uint8_t event[11]; 575 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 576 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 577 } 578 579 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 580 // fetch addr and addr type from db, only called for valid entries 581 bd_addr_t identity_address; 582 int identity_address_type; 583 le_device_db_info(index, &identity_address_type, identity_address, NULL); 584 585 uint8_t event[20]; 586 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 587 event[11] = identity_address_type; 588 reverse_bd_addr(identity_address, &event[12]); 589 little_endian_store_16(event, 18, index); 590 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 591 } 592 593 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 594 uint8_t event[12]; 595 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 596 event[11] = status; 597 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 598 } 599 600 601 static void sm_reencryption_started(sm_connection_t * sm_conn){ 602 603 if (sm_conn->sm_reencryption_active) return; 604 605 sm_conn->sm_reencryption_active = true; 606 607 int identity_addr_type; 608 bd_addr_t identity_addr; 609 if (sm_conn->sm_le_db_index >= 0){ 610 // fetch addr and addr type from db, only called for valid entries 611 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 612 } else { 613 // for legacy pairing with LTK re-construction, use current peer addr 614 identity_addr_type = sm_conn->sm_peer_addr_type; 615 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 616 } 617 618 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 619 } 620 621 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 622 623 if (!sm_conn->sm_reencryption_active) return; 624 625 sm_conn->sm_reencryption_active = false; 626 627 int identity_addr_type; 628 bd_addr_t identity_addr; 629 if (sm_conn->sm_le_db_index >= 0){ 630 // fetch addr and addr type from db, only called for valid entries 631 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 632 } else { 633 // for legacy pairing with LTK re-construction, use current peer addr 634 identity_addr_type = sm_conn->sm_peer_addr_type; 635 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 636 } 637 638 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 639 } 640 641 static void sm_pairing_started(sm_connection_t * sm_conn){ 642 643 if (sm_conn->sm_pairing_active) return; 644 645 sm_conn->sm_pairing_active = true; 646 647 uint8_t event[11]; 648 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 649 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 650 } 651 652 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 653 654 if (!sm_conn->sm_pairing_active) return; 655 656 sm_conn->sm_pairing_active = false; 657 658 uint8_t event[13]; 659 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 660 event[11] = status; 661 event[12] = reason; 662 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 663 } 664 665 // SMP Timeout implementation 666 667 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 668 // the Security Manager Timer shall be reset and started. 669 // 670 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 671 // 672 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 673 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 674 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 675 // established. 676 677 static void sm_timeout_handler(btstack_timer_source_t * timer){ 678 log_info("SM timeout"); 679 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 680 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 681 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 682 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 683 sm_done_for_handle(sm_conn->sm_handle); 684 685 // trigger handling of next ready connection 686 sm_run(); 687 } 688 static void sm_timeout_start(sm_connection_t * sm_conn){ 689 btstack_run_loop_remove_timer(&setup->sm_timeout); 690 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 691 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 692 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 693 btstack_run_loop_add_timer(&setup->sm_timeout); 694 } 695 static void sm_timeout_stop(void){ 696 btstack_run_loop_remove_timer(&setup->sm_timeout); 697 } 698 static void sm_timeout_reset(sm_connection_t * sm_conn){ 699 sm_timeout_stop(); 700 sm_timeout_start(sm_conn); 701 } 702 703 // end of sm timeout 704 705 // GAP Random Address updates 706 static gap_random_address_type_t gap_random_adress_type; 707 static btstack_timer_source_t gap_random_address_update_timer; 708 static uint32_t gap_random_adress_update_period; 709 710 static void gap_random_address_trigger(void){ 711 log_info("gap_random_address_trigger, state %u", rau_state); 712 if (rau_state != RAU_IDLE) return; 713 rau_state = RAU_GET_RANDOM; 714 sm_trigger_run(); 715 } 716 717 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 718 UNUSED(timer); 719 720 log_info("GAP Random Address Update due"); 721 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 722 btstack_run_loop_add_timer(&gap_random_address_update_timer); 723 gap_random_address_trigger(); 724 } 725 726 static void gap_random_address_update_start(void){ 727 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 728 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 729 btstack_run_loop_add_timer(&gap_random_address_update_timer); 730 } 731 732 static void gap_random_address_update_stop(void){ 733 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 734 } 735 736 // ah(k,r) helper 737 // r = padding || r 738 // r - 24 bit value 739 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 740 // r'= padding || r 741 memset(r_prime, 0, 16); 742 (void)memcpy(&r_prime[13], r, 3); 743 } 744 745 // d1 helper 746 // d' = padding || r || d 747 // d,r - 16 bit values 748 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 749 // d'= padding || r || d 750 memset(d1_prime, 0, 16); 751 big_endian_store_16(d1_prime, 12, r); 752 big_endian_store_16(d1_prime, 14, d); 753 } 754 755 // calculate arguments for first AES128 operation in C1 function 756 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 757 758 // p1 = pres || preq || rat’ || iat’ 759 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 760 // cant octet of pres becomes the most significant octet of p1. 761 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 762 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 763 // p1 is 0x05000800000302070710000001010001." 764 765 sm_key_t p1; 766 reverse_56(pres, &p1[0]); 767 reverse_56(preq, &p1[7]); 768 p1[14] = rat; 769 p1[15] = iat; 770 log_info_key("p1", p1); 771 log_info_key("r", r); 772 773 // t1 = r xor p1 774 int i; 775 for (i=0;i<16;i++){ 776 t1[i] = r[i] ^ p1[i]; 777 } 778 log_info_key("t1", t1); 779 } 780 781 // calculate arguments for second AES128 operation in C1 function 782 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 783 // p2 = padding || ia || ra 784 // "The least significant octet of ra becomes the least significant octet of p2 and 785 // the most significant octet of padding becomes the most significant octet of p2. 786 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 787 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 788 789 sm_key_t p2; 790 memset(p2, 0, 16); 791 (void)memcpy(&p2[4], ia, 6); 792 (void)memcpy(&p2[10], ra, 6); 793 log_info_key("p2", p2); 794 795 // c1 = e(k, t2_xor_p2) 796 int i; 797 for (i=0;i<16;i++){ 798 t3[i] = t2[i] ^ p2[i]; 799 } 800 log_info_key("t3", t3); 801 } 802 803 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 804 log_info_key("r1", r1); 805 log_info_key("r2", r2); 806 (void)memcpy(&r_prime[8], &r2[8], 8); 807 (void)memcpy(&r_prime[0], &r1[8], 8); 808 } 809 810 811 // decide on stk generation based on 812 // - pairing request 813 // - io capabilities 814 // - OOB data availability 815 static void sm_setup_tk(void){ 816 817 // horizontal: initiator capabilities 818 // vertial: responder capabilities 819 static const stk_generation_method_t stk_generation_method [5] [5] = { 820 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 821 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 822 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 823 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 824 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 825 }; 826 827 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 828 #ifdef ENABLE_LE_SECURE_CONNECTIONS 829 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 830 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 831 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 832 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 833 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 834 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 835 }; 836 #endif 837 838 // default: just works 839 setup->sm_stk_generation_method = JUST_WORKS; 840 841 #ifdef ENABLE_LE_SECURE_CONNECTIONS 842 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 843 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 844 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 845 #else 846 setup->sm_use_secure_connections = 0; 847 #endif 848 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 849 850 851 // decide if OOB will be used based on SC vs. Legacy and oob flags 852 bool use_oob; 853 if (setup->sm_use_secure_connections){ 854 // In LE Secure Connections pairing, the out of band method is used if at least 855 // one device has the peer device's out of band authentication data available. 856 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 857 } else { 858 // In LE legacy pairing, the out of band method is used if both the devices have 859 // the other device's out of band authentication data available. 860 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 861 } 862 if (use_oob){ 863 log_info("SM: have OOB data"); 864 log_info_key("OOB", setup->sm_tk); 865 setup->sm_stk_generation_method = OOB; 866 return; 867 } 868 869 // If both devices have not set the MITM option in the Authentication Requirements 870 // Flags, then the IO capabilities shall be ignored and the Just Works association 871 // model shall be used. 872 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 873 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 874 log_info("SM: MITM not required by both -> JUST WORKS"); 875 return; 876 } 877 878 // Reset TK as it has been setup in sm_init_setup 879 sm_reset_tk(); 880 881 // Also use just works if unknown io capabilites 882 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 883 return; 884 } 885 886 // Otherwise the IO capabilities of the devices shall be used to determine the 887 // pairing method as defined in Table 2.4. 888 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 889 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 890 891 #ifdef ENABLE_LE_SECURE_CONNECTIONS 892 // table not define by default 893 if (setup->sm_use_secure_connections){ 894 generation_method = stk_generation_method_with_secure_connection; 895 } 896 #endif 897 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 898 899 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 900 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 901 } 902 903 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 904 int flags = 0; 905 if (key_set & SM_KEYDIST_ENC_KEY){ 906 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 907 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 908 } 909 if (key_set & SM_KEYDIST_ID_KEY){ 910 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 911 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 912 } 913 if (key_set & SM_KEYDIST_SIGN){ 914 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 915 } 916 return flags; 917 } 918 919 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 920 setup->sm_key_distribution_received_set = 0; 921 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 922 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 923 setup->sm_key_distribution_sent_set = 0; 924 #ifdef ENABLE_LE_SIGNED_WRITE 925 setup->sm_le_device_index = -1; 926 #endif 927 } 928 929 // CSRK Key Lookup 930 931 932 static int sm_address_resolution_idle(void){ 933 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 934 } 935 936 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 937 (void)memcpy(sm_address_resolution_address, addr, 6); 938 sm_address_resolution_addr_type = addr_type; 939 sm_address_resolution_test = 0; 940 sm_address_resolution_mode = mode; 941 sm_address_resolution_context = context; 942 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 943 } 944 945 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 946 // check if already in list 947 btstack_linked_list_iterator_t it; 948 sm_lookup_entry_t * entry; 949 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 950 while(btstack_linked_list_iterator_has_next(&it)){ 951 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 952 if (entry->address_type != address_type) continue; 953 if (memcmp(entry->address, address, 6)) continue; 954 // already in list 955 return BTSTACK_BUSY; 956 } 957 entry = btstack_memory_sm_lookup_entry_get(); 958 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 959 entry->address_type = (bd_addr_type_t) address_type; 960 (void)memcpy(entry->address, address, 6); 961 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 962 sm_trigger_run(); 963 return 0; 964 } 965 966 // CMAC calculation using AES Engineq 967 #ifdef USE_CMAC_ENGINE 968 969 static void sm_cmac_done_trampoline(void * arg){ 970 UNUSED(arg); 971 sm_cmac_active = 0; 972 (*sm_cmac_done_callback)(sm_cmac_hash); 973 sm_trigger_run(); 974 } 975 976 int sm_cmac_ready(void){ 977 return sm_cmac_active == 0u; 978 } 979 #endif 980 981 #ifdef ENABLE_LE_SECURE_CONNECTIONS 982 // generic cmac calculation 983 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 984 sm_cmac_active = 1; 985 sm_cmac_done_callback = done_callback; 986 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 987 } 988 #endif 989 990 // cmac for ATT Message signing 991 #ifdef ENABLE_LE_SIGNED_WRITE 992 993 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 994 sm_cmac_active = 1; 995 sm_cmac_done_callback = done_callback; 996 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 997 } 998 999 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1000 if (offset >= sm_cmac_signed_write_message_len) { 1001 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1002 return 0; 1003 } 1004 1005 offset = sm_cmac_signed_write_message_len - 1 - offset; 1006 1007 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1008 if (offset < 3){ 1009 return sm_cmac_signed_write_header[offset]; 1010 } 1011 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1012 if (offset < actual_message_len_incl_header){ 1013 return sm_cmac_signed_write_message[offset - 3]; 1014 } 1015 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1016 } 1017 1018 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 1019 // ATT Message Signing 1020 sm_cmac_signed_write_header[0] = opcode; 1021 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1022 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1023 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1024 sm_cmac_signed_write_message = message; 1025 sm_cmac_signed_write_message_len = total_message_len; 1026 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1027 } 1028 #endif 1029 1030 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1031 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1032 uint8_t event[12]; 1033 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1034 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1035 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1036 } 1037 1038 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn){ 1039 uint8_t event[16]; 1040 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1041 sm_setup_event_base(event, sizeof(event), SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, 1042 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1043 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1044 little_endian_store_32(event, 12, passkey); 1045 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1046 } 1047 1048 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1049 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1050 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1051 sm_conn->sm_pairing_active = true; 1052 switch (setup->sm_stk_generation_method){ 1053 case PK_RESP_INPUT: 1054 if (IS_RESPONDER(sm_conn->sm_role)){ 1055 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1056 } else { 1057 sm_trigger_user_response_passkey(sm_conn); 1058 } 1059 break; 1060 case PK_INIT_INPUT: 1061 if (IS_RESPONDER(sm_conn->sm_role)){ 1062 sm_trigger_user_response_passkey(sm_conn); 1063 } else { 1064 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1065 } 1066 break; 1067 case PK_BOTH_INPUT: 1068 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1069 break; 1070 case NUMERIC_COMPARISON: 1071 sm_trigger_user_response_basic(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1072 break; 1073 case JUST_WORKS: 1074 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1075 break; 1076 case OOB: 1077 // client already provided OOB data, let's skip notification. 1078 break; 1079 default: 1080 btstack_assert(false); 1081 break; 1082 } 1083 } 1084 1085 static bool sm_key_distribution_all_received(void) { 1086 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, setup->sm_key_distribution_expected_set); 1087 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1088 } 1089 1090 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1091 if (sm_active_connection_handle == con_handle){ 1092 sm_timeout_stop(); 1093 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1094 log_info("sm: connection 0x%x released setup context", con_handle); 1095 1096 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1097 // generate new ec key after each pairing (that used it) 1098 if (setup->sm_use_secure_connections){ 1099 sm_ec_generate_new_key(); 1100 } 1101 #endif 1102 } 1103 } 1104 1105 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1106 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1107 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1108 sm_done_for_handle(connection->sm_handle); 1109 } 1110 1111 static int sm_key_distribution_flags_for_auth_req(void){ 1112 1113 int flags = SM_KEYDIST_ID_KEY; 1114 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1115 // encryption and signing information only if bonding requested 1116 flags |= SM_KEYDIST_ENC_KEY; 1117 #ifdef ENABLE_LE_SIGNED_WRITE 1118 flags |= SM_KEYDIST_SIGN; 1119 #endif 1120 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1121 // LinkKey for CTKD requires SC 1122 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1123 flags |= SM_KEYDIST_LINK_KEY; 1124 } 1125 #endif 1126 } 1127 return flags; 1128 } 1129 1130 static void sm_reset_setup(void){ 1131 // fill in sm setup 1132 setup->sm_state_vars = 0; 1133 setup->sm_keypress_notification = 0; 1134 setup->sm_have_oob_data = 0; 1135 sm_reset_tk(); 1136 } 1137 1138 static void sm_init_setup(sm_connection_t * sm_conn){ 1139 // fill in sm setup 1140 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1141 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1142 1143 // query client for Legacy Pairing OOB data 1144 if (sm_get_oob_data != NULL) { 1145 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1146 } 1147 1148 // if available and SC supported, also ask for SC OOB Data 1149 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1150 memset(setup->sm_ra, 0, 16); 1151 memset(setup->sm_rb, 0, 16); 1152 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1153 if (sm_get_sc_oob_data != NULL){ 1154 if (IS_RESPONDER(sm_conn->sm_role)){ 1155 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1156 sm_conn->sm_peer_addr_type, 1157 sm_conn->sm_peer_address, 1158 setup->sm_peer_confirm, 1159 setup->sm_ra); 1160 } else { 1161 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1162 sm_conn->sm_peer_addr_type, 1163 sm_conn->sm_peer_address, 1164 setup->sm_peer_confirm, 1165 setup->sm_rb); 1166 } 1167 } else { 1168 setup->sm_have_oob_data = 0; 1169 } 1170 } 1171 #endif 1172 1173 sm_pairing_packet_t * local_packet; 1174 if (IS_RESPONDER(sm_conn->sm_role)){ 1175 // slave 1176 local_packet = &setup->sm_s_pres; 1177 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1178 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1179 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1180 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1181 } else { 1182 // master 1183 local_packet = &setup->sm_m_preq; 1184 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1185 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1186 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1187 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1188 1189 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1190 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1191 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1192 } 1193 1194 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1195 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1196 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1197 // enable SC for SC only mode 1198 if (sm_sc_only_mode){ 1199 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1200 max_encryption_key_size = 16; 1201 } 1202 #endif 1203 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1204 // set CT2 if SC + Bonding + CTKD 1205 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1206 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1207 auth_req |= SM_AUTHREQ_CT2; 1208 } 1209 #endif 1210 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1211 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1212 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1213 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1214 } 1215 1216 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1217 1218 sm_pairing_packet_t * remote_packet; 1219 uint8_t keys_to_send; 1220 uint8_t keys_to_receive; 1221 if (IS_RESPONDER(sm_conn->sm_role)){ 1222 // slave / responder 1223 remote_packet = &setup->sm_m_preq; 1224 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1225 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1226 } else { 1227 // master / initiator 1228 remote_packet = &setup->sm_s_pres; 1229 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1230 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1231 } 1232 1233 // check key size 1234 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1235 // SC Only mandates 128 bit key size 1236 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1237 return SM_REASON_ENCRYPTION_KEY_SIZE; 1238 } 1239 #endif 1240 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1241 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1242 1243 // decide on STK generation method / SC 1244 sm_setup_tk(); 1245 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1246 1247 // check if STK generation method is acceptable by client 1248 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1249 1250 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1251 // Check LE SC Only mode 1252 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1253 log_info("SC Only mode active but SC not possible"); 1254 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1255 } 1256 1257 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1258 if (setup->sm_use_secure_connections){ 1259 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1260 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1261 } 1262 #endif 1263 1264 // identical to responder 1265 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1266 1267 // JUST WORKS doens't provide authentication 1268 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1269 1270 return 0; 1271 } 1272 1273 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1274 1275 // cache and reset context 1276 int matched_device_id = sm_address_resolution_test; 1277 address_resolution_mode_t mode = sm_address_resolution_mode; 1278 void * context = sm_address_resolution_context; 1279 1280 // reset context 1281 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1282 sm_address_resolution_context = NULL; 1283 sm_address_resolution_test = -1; 1284 hci_con_handle_t con_handle = 0; 1285 1286 sm_connection_t * sm_connection; 1287 sm_key_t ltk; 1288 bool have_ltk; 1289 #ifdef ENABLE_LE_CENTRAL 1290 bool trigger_pairing; 1291 #endif 1292 switch (mode){ 1293 case ADDRESS_RESOLUTION_GENERAL: 1294 break; 1295 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1296 sm_connection = (sm_connection_t *) context; 1297 con_handle = sm_connection->sm_handle; 1298 1299 // have ltk -> start encryption / send security request 1300 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1301 // "When a bond has been created between two devices, any reconnection should result in the local device 1302 // enabling or requesting encryption with the remote device before initiating any service request." 1303 1304 switch (event){ 1305 case ADDRESS_RESOLUTION_SUCCEEDED: 1306 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1307 sm_connection->sm_le_db_index = matched_device_id; 1308 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1309 1310 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1311 have_ltk = !sm_is_null_key(ltk); 1312 1313 if (sm_connection->sm_role) { 1314 #ifdef ENABLE_LE_PERIPHERAL 1315 // IRK required before, continue 1316 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1317 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1318 break; 1319 } 1320 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1321 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1322 break; 1323 } 1324 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1325 sm_connection->sm_pairing_requested = 0; 1326 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1327 // trigger security request for Proactive Authentication if LTK available 1328 trigger_security_request = trigger_security_request || have_ltk; 1329 #endif 1330 1331 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1332 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1333 1334 if (trigger_security_request){ 1335 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1336 if (have_ltk){ 1337 sm_reencryption_started(sm_connection); 1338 } else { 1339 sm_pairing_started(sm_connection); 1340 } 1341 sm_trigger_run(); 1342 } 1343 #endif 1344 } else { 1345 1346 #ifdef ENABLE_LE_CENTRAL 1347 // check if pairing already requested and reset requests 1348 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1349 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1350 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1351 sm_connection->sm_security_request_received = 0; 1352 sm_connection->sm_pairing_requested = 0; 1353 bool trigger_reencryption = false; 1354 1355 if (have_ltk){ 1356 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1357 trigger_reencryption = true; 1358 #else 1359 if (trigger_pairing){ 1360 trigger_reencryption = true; 1361 } else { 1362 log_info("central: defer enabling encryption for bonded device"); 1363 } 1364 #endif 1365 } 1366 1367 if (trigger_reencryption){ 1368 log_info("central: enable encryption for bonded device"); 1369 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1370 break; 1371 } 1372 1373 // pairing_request -> send pairing request 1374 if (trigger_pairing){ 1375 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1376 break; 1377 } 1378 #endif 1379 } 1380 break; 1381 case ADDRESS_RESOLUTION_FAILED: 1382 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1383 if (sm_connection->sm_role) { 1384 #ifdef ENABLE_LE_PERIPHERAL 1385 // LTK request received before, IRK required -> negative LTK reply 1386 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1387 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1388 } 1389 // send security request if requested 1390 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1391 sm_connection->sm_pairing_requested = 0; 1392 if (trigger_security_request){ 1393 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1394 sm_pairing_started(sm_connection); 1395 } 1396 break; 1397 #endif 1398 } 1399 #ifdef ENABLE_LE_CENTRAL 1400 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1401 sm_connection->sm_security_request_received = 0; 1402 sm_connection->sm_pairing_requested = 0; 1403 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1404 #endif 1405 break; 1406 1407 default: 1408 btstack_assert(false); 1409 break; 1410 } 1411 break; 1412 default: 1413 break; 1414 } 1415 1416 switch (event){ 1417 case ADDRESS_RESOLUTION_SUCCEEDED: 1418 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1419 break; 1420 case ADDRESS_RESOLUTION_FAILED: 1421 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1422 break; 1423 default: 1424 btstack_assert(false); 1425 break; 1426 } 1427 } 1428 1429 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1430 int le_db_index = -1; 1431 1432 // lookup device based on IRK 1433 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1434 int i; 1435 for (i=0; i < le_device_db_max_count(); i++){ 1436 sm_key_t irk; 1437 bd_addr_t address; 1438 int address_type = BD_ADDR_TYPE_UNKNOWN; 1439 le_device_db_info(i, &address_type, address, irk); 1440 // skip unused entries 1441 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1442 // compare Identity Address 1443 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1444 // compare Identity Resolving Key 1445 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1446 1447 log_info("sm: device found for IRK, updating"); 1448 le_db_index = i; 1449 break; 1450 } 1451 } else { 1452 // assert IRK is set to zero 1453 memset(setup->sm_peer_irk, 0, 16); 1454 } 1455 1456 // if not found, lookup via public address if possible 1457 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1458 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1459 int i; 1460 for (i=0; i < le_device_db_max_count(); i++){ 1461 bd_addr_t address; 1462 int address_type = BD_ADDR_TYPE_UNKNOWN; 1463 le_device_db_info(i, &address_type, address, NULL); 1464 // skip unused entries 1465 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1466 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1467 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1468 log_info("sm: device found for public address, updating"); 1469 le_db_index = i; 1470 break; 1471 } 1472 } 1473 } 1474 1475 // if not found, add to db 1476 bool new_to_le_device_db = false; 1477 if (le_db_index < 0) { 1478 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1479 new_to_le_device_db = true; 1480 } 1481 1482 if (le_db_index >= 0){ 1483 1484 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1485 if (!new_to_le_device_db){ 1486 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1487 } 1488 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1489 #else 1490 UNUSED(new_to_le_device_db); 1491 #endif 1492 1493 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1494 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1495 sm_conn->sm_le_db_index = le_db_index; 1496 1497 #ifdef ENABLE_LE_SIGNED_WRITE 1498 // store local CSRK 1499 setup->sm_le_device_index = le_db_index; 1500 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1501 log_info("sm: store local CSRK"); 1502 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1503 le_device_db_local_counter_set(le_db_index, 0); 1504 } 1505 1506 // store remote CSRK 1507 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1508 log_info("sm: store remote CSRK"); 1509 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1510 le_device_db_remote_counter_set(le_db_index, 0); 1511 } 1512 #endif 1513 // store encryption information for secure connections: LTK generated by ECDH 1514 if (setup->sm_use_secure_connections){ 1515 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1516 uint8_t zero_rand[8]; 1517 memset(zero_rand, 0, 8); 1518 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1519 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1520 } 1521 1522 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1523 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1524 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1525 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1526 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1527 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1528 1529 } 1530 } 1531 } 1532 1533 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1534 1535 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1536 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1537 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1538 & SM_AUTHREQ_BONDING ) != 0u; 1539 1540 if (bonding_enabled){ 1541 sm_store_bonding_information(sm_conn); 1542 } else { 1543 log_info("Ignoring received keys, bonding not enabled"); 1544 } 1545 } 1546 1547 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1548 sm_conn->sm_pairing_failed_reason = reason; 1549 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1550 } 1551 1552 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1553 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1554 } 1555 1556 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1557 1558 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1559 static int sm_passkey_used(stk_generation_method_t method); 1560 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1561 1562 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1563 if (setup->sm_stk_generation_method == OOB){ 1564 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1565 } else { 1566 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); 1567 } 1568 } 1569 1570 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1571 if (IS_RESPONDER(sm_conn->sm_role)){ 1572 // Responder 1573 if (setup->sm_stk_generation_method == OOB){ 1574 // generate Nb 1575 log_info("Generate Nb"); 1576 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); 1577 } else { 1578 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1579 } 1580 } else { 1581 // Initiator role 1582 switch (setup->sm_stk_generation_method){ 1583 case JUST_WORKS: 1584 sm_sc_prepare_dhkey_check(sm_conn); 1585 break; 1586 1587 case NUMERIC_COMPARISON: 1588 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1589 break; 1590 case PK_INIT_INPUT: 1591 case PK_RESP_INPUT: 1592 case PK_BOTH_INPUT: 1593 if (setup->sm_passkey_bit < 20u) { 1594 sm_sc_start_calculating_local_confirm(sm_conn); 1595 } else { 1596 sm_sc_prepare_dhkey_check(sm_conn); 1597 } 1598 break; 1599 case OOB: 1600 sm_sc_prepare_dhkey_check(sm_conn); 1601 break; 1602 default: 1603 btstack_assert(false); 1604 break; 1605 } 1606 } 1607 } 1608 1609 static void sm_sc_cmac_done(uint8_t * hash){ 1610 log_info("sm_sc_cmac_done: "); 1611 log_info_hexdump(hash, 16); 1612 1613 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1614 sm_sc_oob_state = SM_SC_OOB_IDLE; 1615 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1616 return; 1617 } 1618 1619 sm_connection_t * sm_conn = sm_cmac_connection; 1620 sm_cmac_connection = NULL; 1621 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1622 link_key_type_t link_key_type; 1623 #endif 1624 1625 switch (sm_conn->sm_engine_state){ 1626 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1627 (void)memcpy(setup->sm_local_confirm, hash, 16); 1628 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1629 break; 1630 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1631 // check 1632 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1633 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1634 break; 1635 } 1636 sm_sc_state_after_receiving_random(sm_conn); 1637 break; 1638 case SM_SC_W4_CALCULATE_G2: { 1639 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1640 big_endian_store_32(setup->sm_tk, 12, vab); 1641 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1642 sm_trigger_user_response(sm_conn); 1643 break; 1644 } 1645 case SM_SC_W4_CALCULATE_F5_SALT: 1646 (void)memcpy(setup->sm_t, hash, 16); 1647 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1648 break; 1649 case SM_SC_W4_CALCULATE_F5_MACKEY: 1650 (void)memcpy(setup->sm_mackey, hash, 16); 1651 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1652 break; 1653 case SM_SC_W4_CALCULATE_F5_LTK: 1654 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1655 // Errata Service Release to the Bluetooth Specification: ESR09 1656 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1657 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1658 (void)memcpy(setup->sm_ltk, hash, 16); 1659 (void)memcpy(setup->sm_local_ltk, hash, 16); 1660 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1661 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1662 break; 1663 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1664 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1665 if (IS_RESPONDER(sm_conn->sm_role)){ 1666 // responder 1667 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1668 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1669 } else { 1670 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1671 } 1672 } else { 1673 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1674 } 1675 break; 1676 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1677 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1678 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1679 break; 1680 } 1681 if (IS_RESPONDER(sm_conn->sm_role)){ 1682 // responder 1683 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1684 } else { 1685 // initiator 1686 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1687 } 1688 break; 1689 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1690 case SM_SC_W4_CALCULATE_ILK: 1691 (void)memcpy(setup->sm_t, hash, 16); 1692 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1693 break; 1694 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1695 reverse_128(hash, setup->sm_t); 1696 link_key_type = sm_conn->sm_connection_authenticated ? 1697 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1698 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1699 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1700 if (IS_RESPONDER(sm_conn->sm_role)){ 1701 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1702 } else { 1703 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1704 } 1705 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1706 sm_done_for_handle(sm_conn->sm_handle); 1707 break; 1708 case SM_BR_EDR_W4_CALCULATE_ILK: 1709 (void)memcpy(setup->sm_t, hash, 16); 1710 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1711 break; 1712 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1713 log_info("Derived LE LTK from BR/EDR Link Key"); 1714 log_info_key("Link Key", hash); 1715 (void)memcpy(setup->sm_ltk, hash, 16); 1716 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1717 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1718 sm_store_bonding_information(sm_conn); 1719 sm_done_for_handle(sm_conn->sm_handle); 1720 break; 1721 #endif 1722 default: 1723 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1724 break; 1725 } 1726 sm_trigger_run(); 1727 } 1728 1729 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){ 1730 const uint16_t message_len = 65; 1731 sm_cmac_connection = sm_conn; 1732 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1733 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1734 sm_cmac_sc_buffer[64] = z; 1735 log_info("f4 key"); 1736 log_info_hexdump(x, 16); 1737 log_info("f4 message"); 1738 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1739 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1740 } 1741 1742 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1743 static const uint8_t f5_length[] = { 0x01, 0x00}; 1744 1745 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1746 1747 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1748 1749 log_info("f5_calculate_salt"); 1750 // calculate salt for f5 1751 const uint16_t message_len = 32; 1752 sm_cmac_connection = sm_conn; 1753 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1754 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1755 } 1756 1757 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){ 1758 const uint16_t message_len = 53; 1759 sm_cmac_connection = sm_conn; 1760 1761 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1762 sm_cmac_sc_buffer[0] = 0; 1763 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1764 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1765 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1766 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1767 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1768 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1769 log_info("f5 key"); 1770 log_info_hexdump(t, 16); 1771 log_info("f5 message for MacKey"); 1772 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1773 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1774 } 1775 1776 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1777 sm_key56_t bd_addr_master, bd_addr_slave; 1778 bd_addr_master[0] = setup->sm_m_addr_type; 1779 bd_addr_slave[0] = setup->sm_s_addr_type; 1780 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1781 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1782 if (IS_RESPONDER(sm_conn->sm_role)){ 1783 // responder 1784 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1785 } else { 1786 // initiator 1787 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1788 } 1789 } 1790 1791 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1792 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1793 const uint16_t message_len = 53; 1794 sm_cmac_connection = sm_conn; 1795 sm_cmac_sc_buffer[0] = 1; 1796 // 1..52 setup before 1797 log_info("f5 key"); 1798 log_info_hexdump(t, 16); 1799 log_info("f5 message for LTK"); 1800 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1801 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1802 } 1803 1804 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1805 f5_ltk(sm_conn, setup->sm_t); 1806 } 1807 1808 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){ 1809 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1810 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1811 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1812 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1813 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1814 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1815 } 1816 1817 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1818 const uint16_t message_len = 65; 1819 sm_cmac_connection = sm_conn; 1820 log_info("f6 key"); 1821 log_info_hexdump(w, 16); 1822 log_info("f6 message"); 1823 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1824 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1825 } 1826 1827 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1828 // - U is 256 bits 1829 // - V is 256 bits 1830 // - X is 128 bits 1831 // - Y is 128 bits 1832 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){ 1833 const uint16_t message_len = 80; 1834 sm_cmac_connection = sm_conn; 1835 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1836 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1837 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1838 log_info("g2 key"); 1839 log_info_hexdump(x, 16); 1840 log_info("g2 message"); 1841 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1842 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1843 } 1844 1845 static void g2_calculate(sm_connection_t * sm_conn) { 1846 // calc Va if numeric comparison 1847 if (IS_RESPONDER(sm_conn->sm_role)){ 1848 // responder 1849 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1850 } else { 1851 // initiator 1852 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1853 } 1854 } 1855 1856 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1857 uint8_t z = 0; 1858 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1859 // some form of passkey 1860 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1861 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1862 setup->sm_passkey_bit++; 1863 } 1864 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1865 } 1866 1867 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1868 // OOB 1869 if (setup->sm_stk_generation_method == OOB){ 1870 if (IS_RESPONDER(sm_conn->sm_role)){ 1871 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1872 } else { 1873 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1874 } 1875 return; 1876 } 1877 1878 uint8_t z = 0; 1879 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1880 // some form of passkey 1881 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1882 // sm_passkey_bit was increased before sending confirm value 1883 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1884 } 1885 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1886 } 1887 1888 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1889 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1890 1891 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1892 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1893 return; 1894 } else { 1895 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1896 } 1897 } 1898 1899 static void sm_sc_dhkey_calculated(void * arg){ 1900 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1901 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1902 if (sm_conn == NULL) return; 1903 1904 log_info("dhkey"); 1905 log_info_hexdump(&setup->sm_dhkey[0], 32); 1906 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1907 // trigger next step 1908 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1909 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1910 } 1911 sm_trigger_run(); 1912 } 1913 1914 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1915 // calculate DHKCheck 1916 sm_key56_t bd_addr_master, bd_addr_slave; 1917 bd_addr_master[0] = setup->sm_m_addr_type; 1918 bd_addr_slave[0] = setup->sm_s_addr_type; 1919 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1920 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1921 uint8_t iocap_a[3]; 1922 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1923 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1924 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1925 uint8_t iocap_b[3]; 1926 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1927 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1928 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1929 if (IS_RESPONDER(sm_conn->sm_role)){ 1930 // responder 1931 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1932 f6_engine(sm_conn, setup->sm_mackey); 1933 } else { 1934 // initiator 1935 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1936 f6_engine(sm_conn, setup->sm_mackey); 1937 } 1938 } 1939 1940 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1941 // validate E = f6() 1942 sm_key56_t bd_addr_master, bd_addr_slave; 1943 bd_addr_master[0] = setup->sm_m_addr_type; 1944 bd_addr_slave[0] = setup->sm_s_addr_type; 1945 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1946 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1947 1948 uint8_t iocap_a[3]; 1949 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1950 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1951 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1952 uint8_t iocap_b[3]; 1953 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1954 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1955 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1956 if (IS_RESPONDER(sm_conn->sm_role)){ 1957 // responder 1958 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1959 f6_engine(sm_conn, setup->sm_mackey); 1960 } else { 1961 // initiator 1962 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1963 f6_engine(sm_conn, setup->sm_mackey); 1964 } 1965 } 1966 1967 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1968 1969 // 1970 // Link Key Conversion Function h6 1971 // 1972 // h6(W, keyID) = AES-CMAC_W(keyID) 1973 // - W is 128 bits 1974 // - keyID is 32 bits 1975 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1976 const uint16_t message_len = 4; 1977 sm_cmac_connection = sm_conn; 1978 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1979 log_info("h6 key"); 1980 log_info_hexdump(w, 16); 1981 log_info("h6 message"); 1982 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1983 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1984 } 1985 // 1986 // Link Key Conversion Function h7 1987 // 1988 // h7(SALT, W) = AES-CMAC_SALT(W) 1989 // - SALT is 128 bits 1990 // - W is 128 bits 1991 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1992 const uint16_t message_len = 16; 1993 sm_cmac_connection = sm_conn; 1994 log_info("h7 key"); 1995 log_info_hexdump(salt, 16); 1996 log_info("h7 message"); 1997 log_info_hexdump(w, 16); 1998 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1999 } 2000 2001 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2002 // Errata Service Release to the Bluetooth Specification: ESR09 2003 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2004 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2005 2006 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2007 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2008 } 2009 2010 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2011 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2012 } 2013 2014 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2015 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2016 } 2017 2018 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2019 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2020 } 2021 2022 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2023 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2024 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2025 } 2026 2027 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2028 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2029 h7_engine(sm_conn, salt, setup->sm_link_key); 2030 } 2031 2032 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2033 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2034 btstack_assert(hci_connection != NULL); 2035 reverse_128(hci_connection->link_key, setup->sm_link_key); 2036 setup->sm_link_key_type = hci_connection->link_key_type; 2037 } 2038 2039 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2040 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; 2041 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2042 } 2043 2044 #endif 2045 2046 #endif 2047 2048 // key management legacy connections: 2049 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2050 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2051 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2052 // - responder reconnects: responder uses LTK receveived from master 2053 2054 // key management secure connections: 2055 // - both devices store same LTK from ECDH key exchange. 2056 2057 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2058 static void sm_load_security_info(sm_connection_t * sm_connection){ 2059 int encryption_key_size; 2060 int authenticated; 2061 int authorized; 2062 int secure_connection; 2063 2064 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2065 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2066 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2067 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); 2068 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2069 sm_connection->sm_connection_authenticated = authenticated; 2070 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2071 sm_connection->sm_connection_sc = secure_connection; 2072 } 2073 #endif 2074 2075 #ifdef ENABLE_LE_PERIPHERAL 2076 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2077 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2078 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2079 // re-establish used key encryption size 2080 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2081 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2082 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2083 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2084 // Legacy paring -> not SC 2085 sm_connection->sm_connection_sc = 0; 2086 log_info("sm: received ltk request with key size %u, authenticated %u", 2087 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2088 } 2089 #endif 2090 2091 // distributed key generation 2092 static bool sm_run_dpkg(void){ 2093 switch (dkg_state){ 2094 case DKG_CALC_IRK: 2095 // already busy? 2096 if (sm_aes128_state == SM_AES128_IDLE) { 2097 log_info("DKG_CALC_IRK started"); 2098 // IRK = d1(IR, 1, 0) 2099 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2100 sm_aes128_state = SM_AES128_ACTIVE; 2101 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2102 return true; 2103 } 2104 break; 2105 case DKG_CALC_DHK: 2106 // already busy? 2107 if (sm_aes128_state == SM_AES128_IDLE) { 2108 log_info("DKG_CALC_DHK started"); 2109 // DHK = d1(IR, 3, 0) 2110 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2111 sm_aes128_state = SM_AES128_ACTIVE; 2112 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2113 return true; 2114 } 2115 break; 2116 default: 2117 break; 2118 } 2119 return false; 2120 } 2121 2122 // random address updates 2123 static bool sm_run_rau(void){ 2124 switch (rau_state){ 2125 case RAU_GET_RANDOM: 2126 rau_state = RAU_W4_RANDOM; 2127 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2128 return true; 2129 case RAU_GET_ENC: 2130 // already busy? 2131 if (sm_aes128_state == SM_AES128_IDLE) { 2132 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2133 sm_aes128_state = SM_AES128_ACTIVE; 2134 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2135 return true; 2136 } 2137 break; 2138 default: 2139 break; 2140 } 2141 return false; 2142 } 2143 2144 // CSRK Lookup 2145 static bool sm_run_csrk(void){ 2146 btstack_linked_list_iterator_t it; 2147 2148 // -- if csrk lookup ready, find connection that require csrk lookup 2149 if (sm_address_resolution_idle()){ 2150 hci_connections_get_iterator(&it); 2151 while(btstack_linked_list_iterator_has_next(&it)){ 2152 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2153 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2154 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2155 // and start lookup 2156 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); 2157 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2158 break; 2159 } 2160 } 2161 } 2162 2163 // -- if csrk lookup ready, resolved addresses for received addresses 2164 if (sm_address_resolution_idle()) { 2165 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2166 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2167 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2168 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2169 btstack_memory_sm_lookup_entry_free(entry); 2170 } 2171 } 2172 2173 // -- Continue with CSRK device lookup by public or resolvable private address 2174 if (!sm_address_resolution_idle()){ 2175 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2176 while (sm_address_resolution_test < le_device_db_max_count()){ 2177 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2178 bd_addr_t addr; 2179 sm_key_t irk; 2180 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2181 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2182 2183 // skip unused entries 2184 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2185 sm_address_resolution_test++; 2186 continue; 2187 } 2188 2189 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2190 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2191 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2192 break; 2193 } 2194 2195 // if connection type is public, it must be a different one 2196 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2197 sm_address_resolution_test++; 2198 continue; 2199 } 2200 2201 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2202 2203 log_info("LE Device Lookup: calculate AH"); 2204 log_info_key("IRK", irk); 2205 2206 (void)memcpy(sm_aes128_key, irk, 16); 2207 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2208 sm_address_resolution_ah_calculation_active = 1; 2209 sm_aes128_state = SM_AES128_ACTIVE; 2210 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2211 return true; 2212 } 2213 2214 if (sm_address_resolution_test >= le_device_db_max_count()){ 2215 log_info("LE Device Lookup: not found"); 2216 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2217 } 2218 } 2219 return false; 2220 } 2221 2222 // SC OOB 2223 static bool sm_run_oob(void){ 2224 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2225 switch (sm_sc_oob_state){ 2226 case SM_SC_OOB_W2_CALC_CONFIRM: 2227 if (!sm_cmac_ready()) break; 2228 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2229 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2230 return true; 2231 default: 2232 break; 2233 } 2234 #endif 2235 return false; 2236 } 2237 2238 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2239 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2240 } 2241 2242 // handle basic actions that don't requires the full context 2243 static bool sm_run_basic(void){ 2244 btstack_linked_list_iterator_t it; 2245 hci_connections_get_iterator(&it); 2246 while(btstack_linked_list_iterator_has_next(&it)){ 2247 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2248 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2249 switch(sm_connection->sm_engine_state){ 2250 2251 // general 2252 case SM_GENERAL_SEND_PAIRING_FAILED: { 2253 uint8_t buffer[2]; 2254 buffer[0] = SM_CODE_PAIRING_FAILED; 2255 buffer[1] = sm_connection->sm_pairing_failed_reason; 2256 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2257 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2258 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2259 sm_done_for_handle(sm_connection->sm_handle); 2260 break; 2261 } 2262 2263 // responder side 2264 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2265 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2266 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2267 return true; 2268 2269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2270 case SM_SC_RECEIVED_LTK_REQUEST: 2271 switch (sm_connection->sm_irk_lookup_state){ 2272 case IRK_LOOKUP_FAILED: 2273 log_info("LTK Request: IRK Lookup Failed)"); 2274 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2275 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2276 return true; 2277 default: 2278 break; 2279 } 2280 break; 2281 #endif 2282 default: 2283 break; 2284 } 2285 } 2286 return false; 2287 } 2288 2289 static void sm_run_activate_connection(void){ 2290 // Find connections that requires setup context and make active if no other is locked 2291 btstack_linked_list_iterator_t it; 2292 hci_connections_get_iterator(&it); 2293 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2294 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2295 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2296 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2297 bool done = true; 2298 int err; 2299 UNUSED(err); 2300 2301 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2302 // assert ec key is ready 2303 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2304 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2305 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2306 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2307 sm_ec_generate_new_key(); 2308 } 2309 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2310 continue; 2311 } 2312 } 2313 #endif 2314 2315 switch (sm_connection->sm_engine_state) { 2316 #ifdef ENABLE_LE_PERIPHERAL 2317 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2318 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2319 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2320 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2321 case SM_SC_RECEIVED_LTK_REQUEST: 2322 #endif 2323 #endif 2324 #ifdef ENABLE_LE_CENTRAL 2325 case SM_INITIATOR_PH4_HAS_LTK: 2326 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2327 #endif 2328 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2329 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2330 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2331 #endif 2332 // just lock context 2333 break; 2334 default: 2335 done = false; 2336 break; 2337 } 2338 if (done){ 2339 sm_active_connection_handle = sm_connection->sm_handle; 2340 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); 2341 } 2342 } 2343 } 2344 2345 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2346 int i; 2347 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2348 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2349 uint8_t action = 0; 2350 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2351 if (flags & (1u<<i)){ 2352 bool clear_flag = true; 2353 switch (i){ 2354 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2355 case SM_KEYPRESS_PASSKEY_CLEARED: 2356 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2357 default: 2358 break; 2359 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2360 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2361 num_actions--; 2362 clear_flag = num_actions == 0u; 2363 break; 2364 } 2365 if (clear_flag){ 2366 flags &= ~(1<<i); 2367 } 2368 action = i; 2369 break; 2370 } 2371 } 2372 setup->sm_keypress_notification = (num_actions << 5) | flags; 2373 2374 // send keypress notification 2375 uint8_t buffer[2]; 2376 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2377 buffer[1] = action; 2378 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2379 2380 // try 2381 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2382 } 2383 2384 static void sm_run_distribute_keys(sm_connection_t * connection){ 2385 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2386 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2387 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2388 uint8_t buffer[17]; 2389 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2390 reverse_128(setup->sm_ltk, &buffer[1]); 2391 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2392 sm_timeout_reset(connection); 2393 return; 2394 } 2395 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2396 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2397 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2398 uint8_t buffer[11]; 2399 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2400 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2401 reverse_64(setup->sm_local_rand, &buffer[3]); 2402 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2403 sm_timeout_reset(connection); 2404 return; 2405 } 2406 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2407 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2408 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2409 uint8_t buffer[17]; 2410 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2411 reverse_128(sm_persistent_irk, &buffer[1]); 2412 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2413 sm_timeout_reset(connection); 2414 return; 2415 } 2416 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2417 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2418 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2419 bd_addr_t local_address; 2420 uint8_t buffer[8]; 2421 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2422 switch (gap_random_address_get_mode()){ 2423 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2424 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2425 // public or static random 2426 gap_le_get_own_address(&buffer[1], local_address); 2427 break; 2428 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2429 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2430 // fallback to public 2431 gap_local_bd_addr(local_address); 2432 buffer[1] = 0; 2433 break; 2434 default: 2435 btstack_assert(false); 2436 break; 2437 } 2438 reverse_bd_addr(local_address, &buffer[2]); 2439 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2440 sm_timeout_reset(connection); 2441 return; 2442 } 2443 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2444 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2445 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2446 2447 #ifdef ENABLE_LE_SIGNED_WRITE 2448 // hack to reproduce test runs 2449 if (test_use_fixed_local_csrk){ 2450 memset(setup->sm_local_csrk, 0xcc, 16); 2451 } 2452 2453 // store local CSRK 2454 if (setup->sm_le_device_index >= 0){ 2455 log_info("sm: store local CSRK"); 2456 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2457 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2458 } 2459 #endif 2460 2461 uint8_t buffer[17]; 2462 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2463 reverse_128(setup->sm_local_csrk, &buffer[1]); 2464 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2465 sm_timeout_reset(connection); 2466 return; 2467 } 2468 btstack_assert(false); 2469 } 2470 2471 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2472 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2473 // requirements to derive link key from LE: 2474 // - use secure connections 2475 if (setup->sm_use_secure_connections == 0) return false; 2476 // - bonding needs to be enabled: 2477 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; 2478 if (!bonding_enabled) return false; 2479 // - need identity address / public addr 2480 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2481 if (!have_identity_address_info) return false; 2482 // - 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) 2483 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2484 // If SC is authenticated, we consider it safe to overwrite a stored key. 2485 // 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. 2486 uint8_t link_key[16]; 2487 link_key_type_t link_key_type; 2488 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2489 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2490 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2491 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2492 return false; 2493 } 2494 // get started (all of the above are true) 2495 return true; 2496 #else 2497 UNUSED(sm_connection); 2498 return false; 2499 #endif 2500 } 2501 2502 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2503 if (sm_ctkd_from_le(connection)){ 2504 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 2505 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2506 } else { 2507 connection->sm_engine_state = SM_RESPONDER_IDLE; 2508 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2509 sm_done_for_handle(connection->sm_handle); 2510 } 2511 } 2512 2513 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2514 if (sm_ctkd_from_le(connection)){ 2515 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 2516 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2517 } else { 2518 sm_master_pairing_success(connection); 2519 } 2520 } 2521 2522 static void sm_run(void){ 2523 2524 // assert that stack has already bootet 2525 if (hci_get_state() != HCI_STATE_WORKING) return; 2526 2527 // assert that we can send at least commands 2528 if (!hci_can_send_command_packet_now()) return; 2529 2530 // pause until IR/ER are ready 2531 if (sm_persistent_keys_random_active) return; 2532 2533 bool done; 2534 2535 // 2536 // non-connection related behaviour 2537 // 2538 2539 done = sm_run_dpkg(); 2540 if (done) return; 2541 2542 done = sm_run_rau(); 2543 if (done) return; 2544 2545 done = sm_run_csrk(); 2546 if (done) return; 2547 2548 done = sm_run_oob(); 2549 if (done) return; 2550 2551 // assert that we can send at least commands - cmd might have been sent by crypto engine 2552 if (!hci_can_send_command_packet_now()) return; 2553 2554 // handle basic actions that don't requires the full context 2555 done = sm_run_basic(); 2556 if (done) return; 2557 2558 // 2559 // active connection handling 2560 // -- use loop to handle next connection if lock on setup context is released 2561 2562 while (true) { 2563 2564 sm_run_activate_connection(); 2565 2566 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2567 2568 // 2569 // active connection handling 2570 // 2571 2572 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2573 if (!connection) { 2574 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2575 return; 2576 } 2577 2578 // assert that we could send a SM PDU - not needed for all of the following 2579 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2580 log_info("cannot send now, requesting can send now event"); 2581 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2582 return; 2583 } 2584 2585 // send keypress notifications 2586 if (setup->sm_keypress_notification){ 2587 sm_run_send_keypress_notification(connection); 2588 return; 2589 } 2590 2591 int key_distribution_flags; 2592 UNUSED(key_distribution_flags); 2593 #ifdef ENABLE_LE_PERIPHERAL 2594 int err; 2595 bool have_ltk; 2596 uint8_t ltk[16]; 2597 #endif 2598 2599 log_info("sm_run: state %u", connection->sm_engine_state); 2600 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2601 log_info("sm_run // cannot send"); 2602 } 2603 switch (connection->sm_engine_state){ 2604 2605 // secure connections, initiator + responding states 2606 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2607 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2608 if (!sm_cmac_ready()) break; 2609 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2610 sm_sc_calculate_local_confirm(connection); 2611 break; 2612 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2613 if (!sm_cmac_ready()) break; 2614 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2615 sm_sc_calculate_remote_confirm(connection); 2616 break; 2617 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2618 if (!sm_cmac_ready()) break; 2619 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2620 sm_sc_calculate_f6_for_dhkey_check(connection); 2621 break; 2622 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2623 if (!sm_cmac_ready()) break; 2624 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2625 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2626 break; 2627 case SM_SC_W2_CALCULATE_F5_SALT: 2628 if (!sm_cmac_ready()) break; 2629 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2630 f5_calculate_salt(connection); 2631 break; 2632 case SM_SC_W2_CALCULATE_F5_MACKEY: 2633 if (!sm_cmac_ready()) break; 2634 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2635 f5_calculate_mackey(connection); 2636 break; 2637 case SM_SC_W2_CALCULATE_F5_LTK: 2638 if (!sm_cmac_ready()) break; 2639 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2640 f5_calculate_ltk(connection); 2641 break; 2642 case SM_SC_W2_CALCULATE_G2: 2643 if (!sm_cmac_ready()) break; 2644 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2645 g2_calculate(connection); 2646 break; 2647 #endif 2648 2649 #ifdef ENABLE_LE_CENTRAL 2650 // initiator side 2651 2652 case SM_INITIATOR_PH4_HAS_LTK: { 2653 sm_reset_setup(); 2654 sm_load_security_info(connection); 2655 sm_reencryption_started(connection); 2656 2657 sm_key_t peer_ltk_flipped; 2658 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2659 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2660 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2661 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2662 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2663 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2664 return; 2665 } 2666 2667 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2668 sm_reset_setup(); 2669 sm_init_setup(connection); 2670 sm_timeout_start(connection); 2671 sm_pairing_started(connection); 2672 2673 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2674 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2675 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2676 sm_timeout_reset(connection); 2677 break; 2678 #endif 2679 2680 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2681 2682 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2683 bool trigger_user_response = false; 2684 bool trigger_start_calculating_local_confirm = false; 2685 uint8_t buffer[65]; 2686 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2687 // 2688 reverse_256(&ec_q[0], &buffer[1]); 2689 reverse_256(&ec_q[32], &buffer[33]); 2690 2691 #ifdef ENABLE_TESTING_SUPPORT 2692 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2693 log_info("testing_support: invalidating public key"); 2694 // flip single bit of public key coordinate 2695 buffer[1] ^= 1; 2696 } 2697 #endif 2698 2699 // stk generation method 2700 // passkey entry: notify app to show passkey or to request passkey 2701 switch (setup->sm_stk_generation_method){ 2702 case JUST_WORKS: 2703 case NUMERIC_COMPARISON: 2704 if (IS_RESPONDER(connection->sm_role)){ 2705 // responder 2706 trigger_start_calculating_local_confirm = true; 2707 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2708 } else { 2709 // initiator 2710 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2711 } 2712 break; 2713 case PK_INIT_INPUT: 2714 case PK_RESP_INPUT: 2715 case PK_BOTH_INPUT: 2716 // use random TK for display 2717 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2718 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2719 setup->sm_passkey_bit = 0; 2720 2721 if (IS_RESPONDER(connection->sm_role)){ 2722 // responder 2723 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2724 } else { 2725 // initiator 2726 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2727 } 2728 trigger_user_response = true; 2729 break; 2730 case OOB: 2731 if (IS_RESPONDER(connection->sm_role)){ 2732 // responder 2733 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2734 } else { 2735 // initiator 2736 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2737 } 2738 break; 2739 default: 2740 btstack_assert(false); 2741 break; 2742 } 2743 2744 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2745 sm_timeout_reset(connection); 2746 2747 // trigger user response and calc confirm after sending pdu 2748 if (trigger_user_response){ 2749 sm_trigger_user_response(connection); 2750 } 2751 if (trigger_start_calculating_local_confirm){ 2752 sm_sc_start_calculating_local_confirm(connection); 2753 } 2754 break; 2755 } 2756 case SM_SC_SEND_CONFIRMATION: { 2757 uint8_t buffer[17]; 2758 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2759 reverse_128(setup->sm_local_confirm, &buffer[1]); 2760 if (IS_RESPONDER(connection->sm_role)){ 2761 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2762 } else { 2763 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2764 } 2765 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2766 sm_timeout_reset(connection); 2767 break; 2768 } 2769 case SM_SC_SEND_PAIRING_RANDOM: { 2770 uint8_t buffer[17]; 2771 buffer[0] = SM_CODE_PAIRING_RANDOM; 2772 reverse_128(setup->sm_local_nonce, &buffer[1]); 2773 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2774 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2775 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2776 if (IS_RESPONDER(connection->sm_role)){ 2777 // responder 2778 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2779 } else { 2780 // initiator 2781 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2782 } 2783 } else { 2784 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2785 if (IS_RESPONDER(connection->sm_role)){ 2786 // responder 2787 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2788 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2789 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2790 } else { 2791 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2792 sm_sc_prepare_dhkey_check(connection); 2793 } 2794 } else { 2795 // initiator 2796 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2797 } 2798 } 2799 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2800 sm_timeout_reset(connection); 2801 break; 2802 } 2803 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2804 uint8_t buffer[17]; 2805 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2806 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2807 2808 if (IS_RESPONDER(connection->sm_role)){ 2809 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2810 } else { 2811 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2812 } 2813 2814 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2815 sm_timeout_reset(connection); 2816 break; 2817 } 2818 2819 #endif 2820 2821 #ifdef ENABLE_LE_PERIPHERAL 2822 2823 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2824 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2825 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2826 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2827 sm_timeout_start(connection); 2828 break; 2829 } 2830 2831 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2832 case SM_SC_RECEIVED_LTK_REQUEST: 2833 switch (connection->sm_irk_lookup_state){ 2834 case IRK_LOOKUP_SUCCEEDED: 2835 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2836 // start using context by loading security info 2837 sm_reset_setup(); 2838 sm_load_security_info(connection); 2839 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2840 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2841 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2842 sm_reencryption_started(connection); 2843 sm_trigger_run(); 2844 break; 2845 } 2846 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2847 connection->sm_engine_state = SM_RESPONDER_IDLE; 2848 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2849 return; 2850 default: 2851 // just wait until IRK lookup is completed 2852 break; 2853 } 2854 break; 2855 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2856 2857 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2858 sm_reset_setup(); 2859 2860 // handle Pairing Request with LTK available 2861 switch (connection->sm_irk_lookup_state) { 2862 case IRK_LOOKUP_SUCCEEDED: 2863 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2864 have_ltk = !sm_is_null_key(ltk); 2865 if (have_ltk){ 2866 log_info("pairing request but LTK available"); 2867 // emit re-encryption start/fail sequence 2868 sm_reencryption_started(connection); 2869 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2870 } 2871 break; 2872 default: 2873 break; 2874 } 2875 2876 sm_init_setup(connection); 2877 sm_pairing_started(connection); 2878 2879 // recover pairing request 2880 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2881 err = sm_stk_generation_init(connection); 2882 2883 #ifdef ENABLE_TESTING_SUPPORT 2884 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2885 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2886 err = test_pairing_failure; 2887 } 2888 #endif 2889 if (err != 0){ 2890 sm_pairing_error(connection, err); 2891 sm_trigger_run(); 2892 break; 2893 } 2894 2895 sm_timeout_start(connection); 2896 2897 // generate random number first, if we need to show passkey, otherwise send response 2898 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2899 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2900 break; 2901 } 2902 2903 /* fall through */ 2904 2905 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2906 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2907 2908 // start with initiator key dist flags 2909 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2910 2911 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2912 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2913 if (setup->sm_use_secure_connections){ 2914 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2915 } 2916 #endif 2917 // setup in response 2918 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); 2919 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); 2920 2921 // update key distribution after ENC was dropped 2922 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)); 2923 2924 if (setup->sm_use_secure_connections){ 2925 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2926 } else { 2927 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2928 } 2929 2930 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2931 sm_timeout_reset(connection); 2932 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2933 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2934 sm_trigger_user_response(connection); 2935 } 2936 return; 2937 #endif 2938 2939 case SM_PH2_SEND_PAIRING_RANDOM: { 2940 uint8_t buffer[17]; 2941 buffer[0] = SM_CODE_PAIRING_RANDOM; 2942 reverse_128(setup->sm_local_random, &buffer[1]); 2943 if (IS_RESPONDER(connection->sm_role)){ 2944 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2945 } else { 2946 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2947 } 2948 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2949 sm_timeout_reset(connection); 2950 break; 2951 } 2952 2953 case SM_PH2_C1_GET_ENC_A: 2954 // already busy? 2955 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2956 // calculate confirm using aes128 engine - step 1 2957 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); 2958 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2959 sm_aes128_state = SM_AES128_ACTIVE; 2960 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); 2961 break; 2962 2963 case SM_PH2_C1_GET_ENC_C: 2964 // already busy? 2965 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2966 // calculate m_confirm using aes128 engine - step 1 2967 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); 2968 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2969 sm_aes128_state = SM_AES128_ACTIVE; 2970 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); 2971 break; 2972 2973 case SM_PH2_CALC_STK: 2974 // already busy? 2975 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2976 // calculate STK 2977 if (IS_RESPONDER(connection->sm_role)){ 2978 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2979 } else { 2980 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2981 } 2982 connection->sm_engine_state = SM_PH2_W4_STK; 2983 sm_aes128_state = SM_AES128_ACTIVE; 2984 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); 2985 break; 2986 2987 case SM_PH3_Y_GET_ENC: 2988 // already busy? 2989 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2990 // PH3B2 - calculate Y from - enc 2991 2992 // dm helper (was sm_dm_r_prime) 2993 // r' = padding || r 2994 // r - 64 bit value 2995 memset(&sm_aes128_plaintext[0], 0, 8); 2996 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2997 2998 // Y = dm(DHK, Rand) 2999 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3000 sm_aes128_state = SM_AES128_ACTIVE; 3001 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); 3002 break; 3003 3004 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3005 uint8_t buffer[17]; 3006 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3007 reverse_128(setup->sm_local_confirm, &buffer[1]); 3008 if (IS_RESPONDER(connection->sm_role)){ 3009 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3010 } else { 3011 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3012 } 3013 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3014 sm_timeout_reset(connection); 3015 return; 3016 } 3017 #ifdef ENABLE_LE_PERIPHERAL 3018 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3019 sm_key_t stk_flipped; 3020 reverse_128(setup->sm_ltk, stk_flipped); 3021 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3022 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3023 return; 3024 } 3025 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3026 // allow to override LTK 3027 if (sm_get_ltk_callback != NULL){ 3028 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3029 } 3030 sm_key_t ltk_flipped; 3031 reverse_128(setup->sm_ltk, ltk_flipped); 3032 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3033 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3034 return; 3035 } 3036 3037 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3038 // already busy? 3039 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3040 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3041 3042 sm_reset_setup(); 3043 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3044 3045 sm_reencryption_started(connection); 3046 3047 // dm helper (was sm_dm_r_prime) 3048 // r' = padding || r 3049 // r - 64 bit value 3050 memset(&sm_aes128_plaintext[0], 0, 8); 3051 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3052 3053 // Y = dm(DHK, Rand) 3054 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3055 sm_aes128_state = SM_AES128_ACTIVE; 3056 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); 3057 return; 3058 #endif 3059 #ifdef ENABLE_LE_CENTRAL 3060 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3061 sm_key_t stk_flipped; 3062 reverse_128(setup->sm_ltk, stk_flipped); 3063 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3064 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3065 return; 3066 } 3067 #endif 3068 3069 case SM_PH3_DISTRIBUTE_KEYS: 3070 // send next key 3071 if (setup->sm_key_distribution_send_set != 0){ 3072 sm_run_distribute_keys(connection); 3073 } 3074 3075 // more to send? 3076 if (setup->sm_key_distribution_send_set != 0){ 3077 return; 3078 } 3079 3080 // keys are sent 3081 if (IS_RESPONDER(connection->sm_role)){ 3082 // slave -> receive master keys if any 3083 if (sm_key_distribution_all_received()){ 3084 sm_key_distribution_handle_all_received(connection); 3085 sm_key_distribution_complete_responder(connection); 3086 // start CTKD right away 3087 continue; 3088 } else { 3089 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3090 } 3091 } else { 3092 sm_master_pairing_success(connection); 3093 } 3094 break; 3095 3096 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3097 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3098 // fill in sm setup (lite version of sm_init_setup) 3099 sm_reset_setup(); 3100 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3101 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3102 setup->sm_s_addr_type = connection->sm_own_addr_type; 3103 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3104 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3105 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3106 setup->sm_use_secure_connections = true; 3107 sm_ctkd_fetch_br_edr_link_key(connection); 3108 3109 // Enc Key and IRK if requested 3110 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3111 #ifdef ENABLE_LE_SIGNED_WRITE 3112 // Plus signing key if supported 3113 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3114 #endif 3115 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3116 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3117 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3118 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3119 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3120 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3121 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3122 3123 // set state and send pairing response 3124 sm_timeout_start(connection); 3125 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3126 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3127 break; 3128 3129 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3130 // fill in sm setup (lite version of sm_init_setup) 3131 sm_reset_setup(); 3132 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3133 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3134 setup->sm_s_addr_type = connection->sm_own_addr_type; 3135 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3136 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3137 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3138 setup->sm_use_secure_connections = true; 3139 sm_ctkd_fetch_br_edr_link_key(connection); 3140 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3141 3142 // Enc Key and IRK if requested 3143 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3144 #ifdef ENABLE_LE_SIGNED_WRITE 3145 // Plus signing key if supported 3146 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3147 #endif 3148 // drop flags not requested by initiator 3149 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3150 3151 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3152 // - the IO Capability field, 3153 // - the OOB data flag field, and 3154 // - all bits in the Auth Req field except the CT2 bit. 3155 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3156 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3157 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3158 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3159 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3160 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3161 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3162 3163 // configure key distribution, LTK is derived locally 3164 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3165 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3166 3167 // set state and send pairing response 3168 sm_timeout_start(connection); 3169 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3170 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3171 break; 3172 case SM_BR_EDR_DISTRIBUTE_KEYS: 3173 if (setup->sm_key_distribution_send_set != 0) { 3174 sm_run_distribute_keys(connection); 3175 return; 3176 } 3177 // keys are sent 3178 if (IS_RESPONDER(connection->sm_role)) { 3179 // responder -> receive master keys if there are any 3180 if (!sm_key_distribution_all_received()){ 3181 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3182 break; 3183 } 3184 } 3185 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3186 sm_ctkd_start_from_br_edr(connection); 3187 continue; 3188 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3189 if (!sm_cmac_ready()) break; 3190 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3191 h6_calculate_ilk_from_le_ltk(connection); 3192 break; 3193 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3194 if (!sm_cmac_ready()) break; 3195 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3196 h6_calculate_br_edr_link_key(connection); 3197 break; 3198 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3199 if (!sm_cmac_ready()) break; 3200 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3201 h7_calculate_ilk_from_le_ltk(connection); 3202 break; 3203 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3204 if (!sm_cmac_ready()) break; 3205 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3206 h6_calculate_ilk_from_br_edr(connection); 3207 break; 3208 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3209 if (!sm_cmac_ready()) break; 3210 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3211 h6_calculate_le_ltk(connection); 3212 break; 3213 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3214 if (!sm_cmac_ready()) break; 3215 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3216 h7_calculate_ilk_from_br_edr(connection); 3217 break; 3218 #endif 3219 3220 default: 3221 break; 3222 } 3223 3224 // check again if active connection was released 3225 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3226 } 3227 } 3228 3229 // sm_aes128_state stays active 3230 static void sm_handle_encryption_result_enc_a(void *arg){ 3231 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3232 sm_aes128_state = SM_AES128_IDLE; 3233 3234 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3235 if (connection == NULL) return; 3236 3237 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3238 sm_aes128_state = SM_AES128_ACTIVE; 3239 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); 3240 } 3241 3242 static void sm_handle_encryption_result_enc_b(void *arg){ 3243 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3244 sm_aes128_state = SM_AES128_IDLE; 3245 3246 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3247 if (connection == NULL) return; 3248 3249 log_info_key("c1!", setup->sm_local_confirm); 3250 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3251 sm_trigger_run(); 3252 } 3253 3254 // sm_aes128_state stays active 3255 static void sm_handle_encryption_result_enc_c(void *arg){ 3256 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3257 sm_aes128_state = SM_AES128_IDLE; 3258 3259 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3260 if (connection == NULL) return; 3261 3262 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3263 sm_aes128_state = SM_AES128_ACTIVE; 3264 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); 3265 } 3266 3267 static void sm_handle_encryption_result_enc_d(void * arg){ 3268 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3269 sm_aes128_state = SM_AES128_IDLE; 3270 3271 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3272 if (connection == NULL) return; 3273 3274 log_info_key("c1!", sm_aes128_ciphertext); 3275 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3276 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3277 sm_trigger_run(); 3278 return; 3279 } 3280 if (IS_RESPONDER(connection->sm_role)){ 3281 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3282 sm_trigger_run(); 3283 } else { 3284 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3285 sm_aes128_state = SM_AES128_ACTIVE; 3286 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); 3287 } 3288 } 3289 3290 static void sm_handle_encryption_result_enc_stk(void *arg){ 3291 sm_aes128_state = SM_AES128_IDLE; 3292 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3293 3294 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3295 if (connection == NULL) return; 3296 3297 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3298 log_info_key("stk", setup->sm_ltk); 3299 if (IS_RESPONDER(connection->sm_role)){ 3300 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3301 } else { 3302 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3303 } 3304 sm_trigger_run(); 3305 } 3306 3307 // sm_aes128_state stays active 3308 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3309 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3310 sm_aes128_state = SM_AES128_IDLE; 3311 3312 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3313 if (connection == NULL) return; 3314 3315 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3316 log_info_hex16("y", setup->sm_local_y); 3317 // PH3B3 - calculate EDIV 3318 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3319 log_info_hex16("ediv", setup->sm_local_ediv); 3320 // PH3B4 - calculate LTK - enc 3321 // LTK = d1(ER, DIV, 0)) 3322 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3323 sm_aes128_state = SM_AES128_ACTIVE; 3324 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); 3325 } 3326 3327 #ifdef ENABLE_LE_PERIPHERAL 3328 // sm_aes128_state stays active 3329 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3330 sm_aes128_state = SM_AES128_IDLE; 3331 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3332 3333 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3334 if (connection == NULL) return; 3335 3336 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3337 log_info_hex16("y", setup->sm_local_y); 3338 3339 // PH3B3 - calculate DIV 3340 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3341 log_info_hex16("ediv", setup->sm_local_ediv); 3342 // PH3B4 - calculate LTK - enc 3343 // LTK = d1(ER, DIV, 0)) 3344 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3345 sm_aes128_state = SM_AES128_ACTIVE; 3346 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); 3347 } 3348 #endif 3349 3350 // sm_aes128_state stays active 3351 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3352 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3353 sm_aes128_state = SM_AES128_IDLE; 3354 3355 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3356 if (connection == NULL) return; 3357 3358 log_info_key("ltk", setup->sm_ltk); 3359 // calc CSRK next 3360 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3361 sm_aes128_state = SM_AES128_ACTIVE; 3362 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); 3363 } 3364 3365 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3366 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3367 sm_aes128_state = SM_AES128_IDLE; 3368 3369 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3370 if (connection == NULL) return; 3371 3372 sm_aes128_state = SM_AES128_IDLE; 3373 log_info_key("csrk", setup->sm_local_csrk); 3374 if (setup->sm_key_distribution_send_set){ 3375 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3376 } else { 3377 // no keys to send, just continue 3378 if (IS_RESPONDER(connection->sm_role)){ 3379 if (sm_key_distribution_all_received()){ 3380 sm_key_distribution_handle_all_received(connection); 3381 sm_key_distribution_complete_responder(connection); 3382 } else { 3383 // slave -> receive master keys 3384 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3385 } 3386 } else { 3387 sm_key_distribution_complete_initiator(connection); 3388 } 3389 } 3390 sm_trigger_run(); 3391 } 3392 3393 #ifdef ENABLE_LE_PERIPHERAL 3394 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3395 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3396 sm_aes128_state = SM_AES128_IDLE; 3397 3398 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3399 if (connection == NULL) return; 3400 3401 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3402 log_info_key("ltk", setup->sm_ltk); 3403 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3404 sm_trigger_run(); 3405 } 3406 #endif 3407 3408 static void sm_handle_encryption_result_address_resolution(void *arg){ 3409 UNUSED(arg); 3410 sm_aes128_state = SM_AES128_IDLE; 3411 3412 sm_address_resolution_ah_calculation_active = 0; 3413 // compare calulated address against connecting device 3414 uint8_t * hash = &sm_aes128_ciphertext[13]; 3415 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3416 log_info("LE Device Lookup: matched resolvable private address"); 3417 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3418 sm_trigger_run(); 3419 return; 3420 } 3421 // no match, try next 3422 sm_address_resolution_test++; 3423 sm_trigger_run(); 3424 } 3425 3426 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3427 UNUSED(arg); 3428 sm_aes128_state = SM_AES128_IDLE; 3429 3430 log_info_key("irk", sm_persistent_irk); 3431 dkg_state = DKG_CALC_DHK; 3432 sm_trigger_run(); 3433 } 3434 3435 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3436 UNUSED(arg); 3437 sm_aes128_state = SM_AES128_IDLE; 3438 3439 log_info_key("dhk", sm_persistent_dhk); 3440 dkg_state = DKG_READY; 3441 sm_trigger_run(); 3442 } 3443 3444 static void sm_handle_encryption_result_rau(void *arg){ 3445 UNUSED(arg); 3446 sm_aes128_state = SM_AES128_IDLE; 3447 3448 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3449 rau_state = RAU_IDLE; 3450 hci_le_random_address_set(sm_random_address); 3451 3452 sm_trigger_run(); 3453 } 3454 3455 static void sm_handle_random_result_rau(void * arg){ 3456 UNUSED(arg); 3457 // non-resolvable vs. resolvable 3458 switch (gap_random_adress_type){ 3459 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3460 // resolvable: use random as prand and calc address hash 3461 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3462 sm_random_address[0u] &= 0x3fu; 3463 sm_random_address[0u] |= 0x40u; 3464 rau_state = RAU_GET_ENC; 3465 break; 3466 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3467 default: 3468 // "The two most significant bits of the address shall be equal to ‘0’"" 3469 sm_random_address[0u] &= 0x3fu; 3470 rau_state = RAU_IDLE; 3471 hci_le_random_address_set(sm_random_address); 3472 break; 3473 } 3474 sm_trigger_run(); 3475 } 3476 3477 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3478 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3479 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3480 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3481 if (connection == NULL) return; 3482 3483 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3484 sm_trigger_run(); 3485 } 3486 3487 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3488 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3489 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3490 if (connection == NULL) return; 3491 3492 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3493 sm_trigger_run(); 3494 } 3495 #endif 3496 3497 static void sm_handle_random_result_ph2_random(void * arg){ 3498 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3499 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3500 if (connection == NULL) return; 3501 3502 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3503 sm_trigger_run(); 3504 } 3505 3506 static void sm_handle_random_result_ph2_tk(void * arg){ 3507 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3508 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3509 if (connection == NULL) return; 3510 3511 sm_reset_tk(); 3512 uint32_t tk; 3513 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3514 // map random to 0-999999 without speding much cycles on a modulus operation 3515 tk = little_endian_read_32(sm_random_data,0); 3516 tk = tk & 0xfffff; // 1048575 3517 if (tk >= 999999u){ 3518 tk = tk - 999999u; 3519 } 3520 } else { 3521 // override with pre-defined passkey 3522 tk = sm_fixed_passkey_in_display_role; 3523 } 3524 big_endian_store_32(setup->sm_tk, 12, tk); 3525 if (IS_RESPONDER(connection->sm_role)){ 3526 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3527 } else { 3528 if (setup->sm_use_secure_connections){ 3529 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3530 } else { 3531 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3532 sm_trigger_user_response(connection); 3533 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3534 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3535 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); 3536 } 3537 } 3538 } 3539 sm_trigger_run(); 3540 } 3541 3542 static void sm_handle_random_result_ph3_div(void * arg){ 3543 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3544 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3545 if (connection == NULL) return; 3546 3547 // use 16 bit from random value as div 3548 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3549 log_info_hex16("div", setup->sm_local_div); 3550 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3551 sm_trigger_run(); 3552 } 3553 3554 static void sm_handle_random_result_ph3_random(void * arg){ 3555 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3556 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3557 if (connection == NULL) return; 3558 3559 reverse_64(sm_random_data, setup->sm_local_rand); 3560 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3561 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3562 // no db for authenticated flag hack: store flag in bit 4 of LSB 3563 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3564 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3565 } 3566 static void sm_validate_er_ir(void){ 3567 // warn about default ER/IR 3568 bool warning = false; 3569 if (sm_ir_is_default()){ 3570 warning = true; 3571 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3572 } 3573 if (sm_er_is_default()){ 3574 warning = true; 3575 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3576 } 3577 if (warning) { 3578 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3579 } 3580 } 3581 3582 static void sm_handle_random_result_ir(void *arg){ 3583 sm_persistent_keys_random_active = false; 3584 if (arg != NULL){ 3585 // key generated, store in tlv 3586 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3587 log_info("Generated IR key. Store in TLV status: %d", status); 3588 UNUSED(status); 3589 } 3590 log_info_key("IR", sm_persistent_ir); 3591 dkg_state = DKG_CALC_IRK; 3592 3593 if (test_use_fixed_local_irk){ 3594 log_info_key("IRK", sm_persistent_irk); 3595 dkg_state = DKG_CALC_DHK; 3596 } 3597 3598 sm_trigger_run(); 3599 } 3600 3601 static void sm_handle_random_result_er(void *arg){ 3602 sm_persistent_keys_random_active = false; 3603 if (arg != 0){ 3604 // key generated, store in tlv 3605 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3606 log_info("Generated ER key. Store in TLV status: %d", status); 3607 UNUSED(status); 3608 } 3609 log_info_key("ER", sm_persistent_er); 3610 3611 // try load ir 3612 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3613 if (key_size == 16){ 3614 // ok, let's continue 3615 log_info("IR from TLV"); 3616 sm_handle_random_result_ir( NULL ); 3617 } else { 3618 // invalid, generate new random one 3619 sm_persistent_keys_random_active = true; 3620 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3621 } 3622 } 3623 3624 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){ 3625 3626 // connection info 3627 sm_conn->sm_handle = con_handle; 3628 sm_conn->sm_role = role; 3629 sm_conn->sm_peer_addr_type = addr_type; 3630 memcpy(sm_conn->sm_peer_address, address, 6); 3631 3632 // security properties 3633 sm_conn->sm_connection_encrypted = 0; 3634 sm_conn->sm_connection_authenticated = 0; 3635 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3636 sm_conn->sm_le_db_index = -1; 3637 sm_conn->sm_reencryption_active = false; 3638 3639 // prepare CSRK lookup (does not involve setup) 3640 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3641 3642 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3643 } 3644 3645 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3646 3647 UNUSED(channel); // ok: there is no channel 3648 UNUSED(size); // ok: fixed format HCI events 3649 3650 sm_connection_t * sm_conn; 3651 hci_con_handle_t con_handle; 3652 uint8_t status; 3653 bd_addr_t addr; 3654 3655 switch (packet_type) { 3656 3657 case HCI_EVENT_PACKET: 3658 switch (hci_event_packet_get_type(packet)) { 3659 3660 case BTSTACK_EVENT_STATE: 3661 switch (btstack_event_state_get_state(packet)){ 3662 case HCI_STATE_WORKING: 3663 log_info("HCI Working!"); 3664 // setup IR/ER with TLV 3665 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3666 if (sm_tlv_impl != NULL){ 3667 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3668 if (key_size == 16){ 3669 // ok, let's continue 3670 log_info("ER from TLV"); 3671 sm_handle_random_result_er( NULL ); 3672 } else { 3673 // invalid, generate random one 3674 sm_persistent_keys_random_active = true; 3675 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3676 } 3677 } else { 3678 sm_validate_er_ir(); 3679 dkg_state = DKG_CALC_IRK; 3680 3681 if (test_use_fixed_local_irk){ 3682 log_info_key("IRK", sm_persistent_irk); 3683 dkg_state = DKG_CALC_DHK; 3684 } 3685 } 3686 3687 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3688 // trigger ECC key generation 3689 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3690 sm_ec_generate_new_key(); 3691 } 3692 #endif 3693 3694 // restart random address updates after power cycle 3695 gap_random_address_set_mode(gap_random_adress_type); 3696 break; 3697 3698 case HCI_STATE_OFF: 3699 case HCI_STATE_HALTING: 3700 log_info("SM: reset state"); 3701 // stop random address update 3702 gap_random_address_update_stop(); 3703 // reset state 3704 sm_state_reset(); 3705 break; 3706 3707 default: 3708 break; 3709 } 3710 break; 3711 3712 #ifdef ENABLE_CLASSIC 3713 case HCI_EVENT_CONNECTION_COMPLETE: 3714 // ignore if connection failed 3715 if (hci_event_connection_complete_get_status(packet)) return; 3716 3717 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3718 sm_conn = sm_get_connection_for_handle(con_handle); 3719 if (!sm_conn) break; 3720 3721 hci_event_connection_complete_get_bd_addr(packet, addr); 3722 sm_connection_init(sm_conn, 3723 con_handle, 3724 (uint8_t) gap_get_role(con_handle), 3725 BD_ADDR_TYPE_LE_PUBLIC, 3726 addr); 3727 // classic connection corresponds to public le address 3728 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3729 gap_local_bd_addr(sm_conn->sm_own_address); 3730 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3731 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3732 break; 3733 #endif 3734 3735 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3736 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3737 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3738 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3739 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3740 if (sm_conn == NULL) break; 3741 sm_conn->sm_pairing_requested = 1; 3742 break; 3743 #endif 3744 3745 case HCI_EVENT_LE_META: 3746 switch (packet[2]) { 3747 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3748 // ignore if connection failed 3749 if (packet[3]) return; 3750 3751 con_handle = little_endian_read_16(packet, 4); 3752 sm_conn = sm_get_connection_for_handle(con_handle); 3753 if (!sm_conn) break; 3754 3755 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3756 sm_connection_init(sm_conn, 3757 con_handle, 3758 hci_subevent_le_connection_complete_get_role(packet), 3759 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3760 addr); 3761 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3762 3763 // track our addr used for this connection and set state 3764 #ifdef ENABLE_LE_PERIPHERAL 3765 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3766 // responder - use own address from advertisements 3767 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3768 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3769 } 3770 #endif 3771 #ifdef ENABLE_LE_CENTRAL 3772 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3773 // initiator - use own address from create connection 3774 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3775 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3776 } 3777 #endif 3778 break; 3779 3780 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3781 con_handle = little_endian_read_16(packet, 3); 3782 sm_conn = sm_get_connection_for_handle(con_handle); 3783 if (!sm_conn) break; 3784 3785 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3786 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3787 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3788 break; 3789 } 3790 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3791 // PH2 SEND LTK as we need to exchange keys in PH3 3792 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3793 break; 3794 } 3795 3796 // store rand and ediv 3797 reverse_64(&packet[5], sm_conn->sm_local_rand); 3798 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3799 3800 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3801 // potentially stored LTK is from the master 3802 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3803 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3804 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3805 break; 3806 } 3807 // additionally check if remote is in LE Device DB if requested 3808 switch(sm_conn->sm_irk_lookup_state){ 3809 case IRK_LOOKUP_FAILED: 3810 log_info("LTK Request: device not in device db"); 3811 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3812 break; 3813 case IRK_LOOKUP_SUCCEEDED: 3814 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3815 break; 3816 default: 3817 // wait for irk look doen 3818 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3819 break; 3820 } 3821 break; 3822 } 3823 3824 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3825 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3826 #else 3827 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3828 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3829 #endif 3830 break; 3831 3832 default: 3833 break; 3834 } 3835 break; 3836 3837 case HCI_EVENT_ENCRYPTION_CHANGE: 3838 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3839 sm_conn = sm_get_connection_for_handle(con_handle); 3840 if (!sm_conn) break; 3841 3842 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3843 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3844 sm_conn->sm_actual_encryption_key_size); 3845 log_info("event handler, state %u", sm_conn->sm_engine_state); 3846 3847 switch (sm_conn->sm_engine_state){ 3848 3849 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3850 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3851 if (sm_conn->sm_connection_encrypted) { 3852 status = ERROR_CODE_SUCCESS; 3853 if (sm_conn->sm_role){ 3854 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3855 } else { 3856 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3857 } 3858 } else { 3859 status = hci_event_encryption_change_get_status(packet); 3860 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3861 // also, gap_reconnect_security_setup_active will return true 3862 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3863 } 3864 3865 // emit re-encryption complete 3866 sm_reencryption_complete(sm_conn, status); 3867 3868 // notify client, if pairing was requested before 3869 if (sm_conn->sm_pairing_requested){ 3870 sm_conn->sm_pairing_requested = 0; 3871 sm_pairing_complete(sm_conn, status, 0); 3872 } 3873 3874 sm_done_for_handle(sm_conn->sm_handle); 3875 break; 3876 3877 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3878 if (!sm_conn->sm_connection_encrypted) break; 3879 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3880 if (IS_RESPONDER(sm_conn->sm_role)){ 3881 // slave 3882 if (setup->sm_use_secure_connections){ 3883 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3884 } else { 3885 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); 3886 } 3887 } else { 3888 // master 3889 if (sm_key_distribution_all_received()){ 3890 // skip receiving keys as there are none 3891 sm_key_distribution_handle_all_received(sm_conn); 3892 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); 3893 } else { 3894 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3895 } 3896 } 3897 break; 3898 3899 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3900 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3901 if (sm_conn->sm_connection_encrypted != 2) break; 3902 // prepare for pairing request 3903 if (IS_RESPONDER(sm_conn->sm_role)){ 3904 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3905 } else if (sm_conn->sm_pairing_requested){ 3906 // only send LE pairing request after BR/EDR SSP 3907 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3908 } 3909 break; 3910 #endif 3911 default: 3912 break; 3913 } 3914 break; 3915 3916 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3917 con_handle = little_endian_read_16(packet, 3); 3918 sm_conn = sm_get_connection_for_handle(con_handle); 3919 if (!sm_conn) break; 3920 3921 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3922 log_info("event handler, state %u", sm_conn->sm_engine_state); 3923 // continue if part of initial pairing 3924 switch (sm_conn->sm_engine_state){ 3925 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3926 if (sm_conn->sm_role){ 3927 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3928 } else { 3929 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3930 } 3931 sm_done_for_handle(sm_conn->sm_handle); 3932 break; 3933 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3934 if (IS_RESPONDER(sm_conn->sm_role)){ 3935 // slave 3936 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); 3937 } else { 3938 // master 3939 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3940 } 3941 break; 3942 default: 3943 break; 3944 } 3945 break; 3946 3947 3948 case HCI_EVENT_DISCONNECTION_COMPLETE: 3949 con_handle = little_endian_read_16(packet, 3); 3950 sm_done_for_handle(con_handle); 3951 sm_conn = sm_get_connection_for_handle(con_handle); 3952 if (!sm_conn) break; 3953 3954 // pairing failed, if it was ongoing 3955 switch (sm_conn->sm_engine_state){ 3956 case SM_GENERAL_IDLE: 3957 case SM_INITIATOR_CONNECTED: 3958 case SM_RESPONDER_IDLE: 3959 break; 3960 default: 3961 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3962 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3963 break; 3964 } 3965 3966 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3967 sm_conn->sm_handle = 0; 3968 break; 3969 3970 case HCI_EVENT_COMMAND_COMPLETE: 3971 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 3972 // set local addr for le device db 3973 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3974 le_device_db_set_local_bd_addr(addr); 3975 } 3976 break; 3977 default: 3978 break; 3979 } 3980 break; 3981 default: 3982 break; 3983 } 3984 3985 sm_run(); 3986 } 3987 3988 static inline int sm_calc_actual_encryption_key_size(int other){ 3989 if (other < sm_min_encryption_key_size) return 0; 3990 if (other < sm_max_encryption_key_size) return other; 3991 return sm_max_encryption_key_size; 3992 } 3993 3994 3995 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3996 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3997 switch (method){ 3998 case JUST_WORKS: 3999 case NUMERIC_COMPARISON: 4000 return 1; 4001 default: 4002 return 0; 4003 } 4004 } 4005 // responder 4006 4007 static int sm_passkey_used(stk_generation_method_t method){ 4008 switch (method){ 4009 case PK_RESP_INPUT: 4010 return 1; 4011 default: 4012 return 0; 4013 } 4014 } 4015 4016 static int sm_passkey_entry(stk_generation_method_t method){ 4017 switch (method){ 4018 case PK_RESP_INPUT: 4019 case PK_INIT_INPUT: 4020 case PK_BOTH_INPUT: 4021 return 1; 4022 default: 4023 return 0; 4024 } 4025 } 4026 4027 #endif 4028 4029 /** 4030 * @return ok 4031 */ 4032 static int sm_validate_stk_generation_method(void){ 4033 // check if STK generation method is acceptable by client 4034 switch (setup->sm_stk_generation_method){ 4035 case JUST_WORKS: 4036 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4037 case PK_RESP_INPUT: 4038 case PK_INIT_INPUT: 4039 case PK_BOTH_INPUT: 4040 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4041 case OOB: 4042 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4043 case NUMERIC_COMPARISON: 4044 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4045 default: 4046 return 0; 4047 } 4048 } 4049 4050 #ifdef ENABLE_LE_CENTRAL 4051 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4052 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4053 if (sm_sc_only_mode){ 4054 uint8_t auth_req = packet[1]; 4055 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4056 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4057 return; 4058 } 4059 } 4060 #else 4061 UNUSED(packet); 4062 #endif 4063 4064 int have_ltk; 4065 uint8_t ltk[16]; 4066 4067 // IRK complete? 4068 switch (sm_conn->sm_irk_lookup_state){ 4069 case IRK_LOOKUP_FAILED: 4070 // start pairing 4071 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4072 break; 4073 case IRK_LOOKUP_SUCCEEDED: 4074 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4075 have_ltk = !sm_is_null_key(ltk); 4076 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4077 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4078 // start re-encrypt if we have LTK and the connection is not already encrypted 4079 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4080 } else { 4081 // start pairing 4082 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4083 } 4084 break; 4085 default: 4086 // otherwise, store security request 4087 sm_conn->sm_security_request_received = 1; 4088 break; 4089 } 4090 } 4091 #endif 4092 4093 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4094 4095 // size of complete sm_pdu used to validate input 4096 static const uint8_t sm_pdu_size[] = { 4097 0, // 0x00 invalid opcode 4098 7, // 0x01 pairing request 4099 7, // 0x02 pairing response 4100 17, // 0x03 pairing confirm 4101 17, // 0x04 pairing random 4102 2, // 0x05 pairing failed 4103 17, // 0x06 encryption information 4104 11, // 0x07 master identification 4105 17, // 0x08 identification information 4106 8, // 0x09 identify address information 4107 17, // 0x0a signing information 4108 2, // 0x0b security request 4109 65, // 0x0c pairing public key 4110 17, // 0x0d pairing dhk check 4111 2, // 0x0e keypress notification 4112 }; 4113 4114 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4115 sm_run(); 4116 } 4117 4118 if (packet_type != SM_DATA_PACKET) return; 4119 if (size == 0u) return; 4120 4121 uint8_t sm_pdu_code = packet[0]; 4122 4123 // validate pdu size 4124 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 4125 if (sm_pdu_size[sm_pdu_code] != size) return; 4126 4127 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4128 if (!sm_conn) return; 4129 4130 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4131 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4132 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4133 sm_done_for_handle(con_handle); 4134 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4135 return; 4136 } 4137 4138 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4139 4140 int err; 4141 UNUSED(err); 4142 4143 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4144 uint8_t buffer[5]; 4145 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4146 buffer[1] = 3; 4147 little_endian_store_16(buffer, 2, con_handle); 4148 buffer[4] = packet[1]; 4149 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4150 return; 4151 } 4152 4153 switch (sm_conn->sm_engine_state){ 4154 4155 // a sm timeout requires a new physical connection 4156 case SM_GENERAL_TIMEOUT: 4157 return; 4158 4159 #ifdef ENABLE_LE_CENTRAL 4160 4161 // Initiator 4162 case SM_INITIATOR_CONNECTED: 4163 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4164 sm_pdu_received_in_wrong_state(sm_conn); 4165 break; 4166 } 4167 sm_initiator_connected_handle_security_request(sm_conn, packet); 4168 break; 4169 4170 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4171 // Core 5, Vol 3, Part H, 2.4.6: 4172 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4173 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4174 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4175 log_info("Ignoring Security Request"); 4176 break; 4177 } 4178 4179 // all other pdus are incorrect 4180 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4181 sm_pdu_received_in_wrong_state(sm_conn); 4182 break; 4183 } 4184 4185 // store pairing request 4186 (void)memcpy(&setup->sm_s_pres, packet, 4187 sizeof(sm_pairing_packet_t)); 4188 err = sm_stk_generation_init(sm_conn); 4189 4190 #ifdef ENABLE_TESTING_SUPPORT 4191 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4192 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4193 err = test_pairing_failure; 4194 } 4195 #endif 4196 4197 if (err != 0){ 4198 sm_pairing_error(sm_conn, err); 4199 break; 4200 } 4201 4202 // generate random number first, if we need to show passkey 4203 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4204 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); 4205 break; 4206 } 4207 4208 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4209 if (setup->sm_use_secure_connections){ 4210 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4211 if (setup->sm_stk_generation_method == JUST_WORKS){ 4212 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4213 sm_trigger_user_response(sm_conn); 4214 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4215 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4216 } 4217 } else { 4218 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4219 } 4220 break; 4221 } 4222 #endif 4223 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4224 sm_trigger_user_response(sm_conn); 4225 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4226 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4227 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); 4228 } 4229 break; 4230 4231 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4232 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4233 sm_pdu_received_in_wrong_state(sm_conn); 4234 break; 4235 } 4236 4237 // store s_confirm 4238 reverse_128(&packet[1], setup->sm_peer_confirm); 4239 4240 // abort if s_confirm matches m_confirm 4241 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4242 sm_pdu_received_in_wrong_state(sm_conn); 4243 break; 4244 } 4245 4246 #ifdef ENABLE_TESTING_SUPPORT 4247 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4248 log_info("testing_support: reset confirm value"); 4249 memset(setup->sm_peer_confirm, 0, 16); 4250 } 4251 #endif 4252 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4253 break; 4254 4255 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4256 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4257 sm_pdu_received_in_wrong_state(sm_conn); 4258 break;; 4259 } 4260 4261 // received random value 4262 reverse_128(&packet[1], setup->sm_peer_random); 4263 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4264 break; 4265 #endif 4266 4267 #ifdef ENABLE_LE_PERIPHERAL 4268 // Responder 4269 case SM_RESPONDER_IDLE: 4270 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4271 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4272 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4273 sm_pdu_received_in_wrong_state(sm_conn); 4274 break;; 4275 } 4276 4277 // store pairing request 4278 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4279 4280 // check if IRK completed 4281 switch (sm_conn->sm_irk_lookup_state){ 4282 case IRK_LOOKUP_SUCCEEDED: 4283 case IRK_LOOKUP_FAILED: 4284 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4285 break; 4286 default: 4287 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4288 break; 4289 } 4290 break; 4291 #endif 4292 4293 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4294 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4295 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4296 sm_pdu_received_in_wrong_state(sm_conn); 4297 break; 4298 } 4299 4300 // store public key for DH Key calculation 4301 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4302 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4303 4304 // CVE-2020-26558: abort pairing if remote uses the same public key 4305 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4306 log_info("Remote PK matches ours"); 4307 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4308 break; 4309 } 4310 4311 // validate public key 4312 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4313 if (err != 0){ 4314 log_info("sm: peer public key invalid %x", err); 4315 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4316 break; 4317 } 4318 4319 // start calculating dhkey 4320 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); 4321 4322 4323 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4324 if (IS_RESPONDER(sm_conn->sm_role)){ 4325 // responder 4326 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4327 } else { 4328 // initiator 4329 // stk generation method 4330 // passkey entry: notify app to show passkey or to request passkey 4331 switch (setup->sm_stk_generation_method){ 4332 case JUST_WORKS: 4333 case NUMERIC_COMPARISON: 4334 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4335 break; 4336 case PK_RESP_INPUT: 4337 sm_sc_start_calculating_local_confirm(sm_conn); 4338 break; 4339 case PK_INIT_INPUT: 4340 case PK_BOTH_INPUT: 4341 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4342 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4343 break; 4344 } 4345 sm_sc_start_calculating_local_confirm(sm_conn); 4346 break; 4347 case OOB: 4348 // generate Nx 4349 log_info("Generate Na"); 4350 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); 4351 break; 4352 default: 4353 btstack_assert(false); 4354 break; 4355 } 4356 } 4357 break; 4358 4359 case SM_SC_W4_CONFIRMATION: 4360 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4361 sm_pdu_received_in_wrong_state(sm_conn); 4362 break; 4363 } 4364 // received confirm value 4365 reverse_128(&packet[1], setup->sm_peer_confirm); 4366 4367 #ifdef ENABLE_TESTING_SUPPORT 4368 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4369 log_info("testing_support: reset confirm value"); 4370 memset(setup->sm_peer_confirm, 0, 16); 4371 } 4372 #endif 4373 if (IS_RESPONDER(sm_conn->sm_role)){ 4374 // responder 4375 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4376 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4377 // still waiting for passkey 4378 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4379 break; 4380 } 4381 } 4382 sm_sc_start_calculating_local_confirm(sm_conn); 4383 } else { 4384 // initiator 4385 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4386 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); 4387 } else { 4388 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4389 } 4390 } 4391 break; 4392 4393 case SM_SC_W4_PAIRING_RANDOM: 4394 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4395 sm_pdu_received_in_wrong_state(sm_conn); 4396 break; 4397 } 4398 4399 // received random value 4400 reverse_128(&packet[1], setup->sm_peer_nonce); 4401 4402 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4403 // only check for JUST WORK/NC in initiator role OR passkey entry 4404 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4405 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4406 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4407 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4408 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4409 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4410 break; 4411 } 4412 4413 // OOB 4414 if (setup->sm_stk_generation_method == OOB){ 4415 4416 // setup local random, set to zero if remote did not receive our data 4417 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4418 if (IS_RESPONDER(sm_conn->sm_role)){ 4419 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4420 log_info("Reset rb as A does not have OOB data"); 4421 memset(setup->sm_rb, 0, 16); 4422 } else { 4423 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4424 log_info("Use stored rb"); 4425 log_info_hexdump(setup->sm_rb, 16); 4426 } 4427 } else { 4428 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4429 log_info("Reset ra as B does not have OOB data"); 4430 memset(setup->sm_ra, 0, 16); 4431 } else { 4432 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4433 log_info("Use stored ra"); 4434 log_info_hexdump(setup->sm_ra, 16); 4435 } 4436 } 4437 4438 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4439 if (setup->sm_have_oob_data){ 4440 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4441 break; 4442 } 4443 } 4444 4445 // TODO: we only get here for Responder role with JW/NC 4446 sm_sc_state_after_receiving_random(sm_conn); 4447 break; 4448 4449 case SM_SC_W2_CALCULATE_G2: 4450 case SM_SC_W4_CALCULATE_G2: 4451 case SM_SC_W4_CALCULATE_DHKEY: 4452 case SM_SC_W2_CALCULATE_F5_SALT: 4453 case SM_SC_W4_CALCULATE_F5_SALT: 4454 case SM_SC_W2_CALCULATE_F5_MACKEY: 4455 case SM_SC_W4_CALCULATE_F5_MACKEY: 4456 case SM_SC_W2_CALCULATE_F5_LTK: 4457 case SM_SC_W4_CALCULATE_F5_LTK: 4458 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4459 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4460 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4461 case SM_SC_W4_USER_RESPONSE: 4462 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4463 sm_pdu_received_in_wrong_state(sm_conn); 4464 break; 4465 } 4466 // store DHKey Check 4467 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4468 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4469 4470 // have we been only waiting for dhkey check command? 4471 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4472 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4473 } 4474 break; 4475 #endif 4476 4477 #ifdef ENABLE_LE_PERIPHERAL 4478 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4479 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4480 sm_pdu_received_in_wrong_state(sm_conn); 4481 break; 4482 } 4483 4484 // received confirm value 4485 reverse_128(&packet[1], setup->sm_peer_confirm); 4486 4487 #ifdef ENABLE_TESTING_SUPPORT 4488 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4489 log_info("testing_support: reset confirm value"); 4490 memset(setup->sm_peer_confirm, 0, 16); 4491 } 4492 #endif 4493 // notify client to hide shown passkey 4494 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4495 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4496 } 4497 4498 // handle user cancel pairing? 4499 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4500 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4501 break; 4502 } 4503 4504 // wait for user action? 4505 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4506 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4507 break; 4508 } 4509 4510 // calculate and send local_confirm 4511 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); 4512 break; 4513 4514 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4515 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4516 sm_pdu_received_in_wrong_state(sm_conn); 4517 break;; 4518 } 4519 4520 // received random value 4521 reverse_128(&packet[1], setup->sm_peer_random); 4522 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4523 break; 4524 #endif 4525 4526 case SM_PH3_RECEIVE_KEYS: 4527 switch(sm_pdu_code){ 4528 case SM_CODE_ENCRYPTION_INFORMATION: 4529 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4530 reverse_128(&packet[1], setup->sm_peer_ltk); 4531 break; 4532 4533 case SM_CODE_MASTER_IDENTIFICATION: 4534 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4535 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4536 reverse_64(&packet[3], setup->sm_peer_rand); 4537 break; 4538 4539 case SM_CODE_IDENTITY_INFORMATION: 4540 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4541 reverse_128(&packet[1], setup->sm_peer_irk); 4542 break; 4543 4544 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4545 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4546 setup->sm_peer_addr_type = packet[1]; 4547 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4548 break; 4549 4550 case SM_CODE_SIGNING_INFORMATION: 4551 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4552 reverse_128(&packet[1], setup->sm_peer_csrk); 4553 break; 4554 default: 4555 // Unexpected PDU 4556 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4557 break; 4558 } 4559 // done with key distribution? 4560 if (sm_key_distribution_all_received()){ 4561 4562 sm_key_distribution_handle_all_received(sm_conn); 4563 4564 if (IS_RESPONDER(sm_conn->sm_role)){ 4565 sm_key_distribution_complete_responder(sm_conn); 4566 } else { 4567 if (setup->sm_use_secure_connections){ 4568 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4569 } else { 4570 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); 4571 } 4572 } 4573 } 4574 break; 4575 4576 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4577 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4578 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4579 sm_pdu_received_in_wrong_state(sm_conn); 4580 break; 4581 } 4582 // store pairing response 4583 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4584 4585 // validate encryption key size 4586 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres)); 4587 // SC Only mandates 128 bit key size 4588 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4589 sm_conn->sm_actual_encryption_key_size = 0; 4590 } 4591 if (sm_conn->sm_actual_encryption_key_size == 0){ 4592 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4593 break; 4594 } 4595 4596 // prepare key exchange, LTK is derived locally 4597 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4598 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4599 4600 // skip receive if there are none 4601 if (sm_key_distribution_all_received()){ 4602 // distribute keys in run handles 'no keys to send' 4603 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4604 } else { 4605 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4606 } 4607 break; 4608 4609 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4610 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4611 sm_pdu_received_in_wrong_state(sm_conn); 4612 break; 4613 } 4614 // store pairing request 4615 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4616 // validate encryption key size 4617 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq)); 4618 // SC Only mandates 128 bit key size 4619 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4620 sm_conn->sm_actual_encryption_key_size = 0; 4621 } 4622 if (sm_conn->sm_actual_encryption_key_size == 0){ 4623 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4624 break; 4625 } 4626 // trigger response 4627 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4628 break; 4629 4630 case SM_BR_EDR_RECEIVE_KEYS: 4631 switch(sm_pdu_code){ 4632 case SM_CODE_IDENTITY_INFORMATION: 4633 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4634 reverse_128(&packet[1], setup->sm_peer_irk); 4635 break; 4636 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4637 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4638 setup->sm_peer_addr_type = packet[1]; 4639 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4640 break; 4641 case SM_CODE_SIGNING_INFORMATION: 4642 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4643 reverse_128(&packet[1], setup->sm_peer_csrk); 4644 break; 4645 default: 4646 // Unexpected PDU 4647 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4648 break; 4649 } 4650 4651 // all keys received 4652 if (sm_key_distribution_all_received()){ 4653 if (IS_RESPONDER(sm_conn->sm_role)){ 4654 // responder -> keys exchanged, derive LE LTK 4655 sm_ctkd_start_from_br_edr(sm_conn); 4656 } else { 4657 // initiator -> send our keys if any 4658 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4659 } 4660 } 4661 break; 4662 #endif 4663 4664 default: 4665 // Unexpected PDU 4666 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4667 sm_pdu_received_in_wrong_state(sm_conn); 4668 break; 4669 } 4670 4671 // try to send next pdu 4672 sm_trigger_run(); 4673 } 4674 4675 // Security Manager Client API 4676 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4677 sm_get_oob_data = get_oob_data_callback; 4678 } 4679 4680 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)){ 4681 sm_get_sc_oob_data = get_sc_oob_data_callback; 4682 } 4683 4684 void sm_register_ltk_callback( bool (*get_ltk_callback)(hci_con_handle_t con_handle, uint8_t address_type, bd_addr_t addr, uint8_t * ltk)){ 4685 sm_get_ltk_callback = get_ltk_callback; 4686 } 4687 4688 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4689 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4690 } 4691 4692 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4693 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4694 } 4695 4696 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4697 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4698 } 4699 4700 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4701 sm_min_encryption_key_size = min_size; 4702 sm_max_encryption_key_size = max_size; 4703 } 4704 4705 void sm_set_authentication_requirements(uint8_t auth_req){ 4706 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4707 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4708 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4709 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4710 } 4711 #endif 4712 sm_auth_req = auth_req; 4713 } 4714 4715 void sm_set_io_capabilities(io_capability_t io_capability){ 4716 sm_io_capabilities = io_capability; 4717 } 4718 4719 #ifdef ENABLE_LE_PERIPHERAL 4720 void sm_set_request_security(int enable){ 4721 sm_slave_request_security = enable; 4722 } 4723 #endif 4724 4725 void sm_set_er(sm_key_t er){ 4726 (void)memcpy(sm_persistent_er, er, 16); 4727 } 4728 4729 void sm_set_ir(sm_key_t ir){ 4730 (void)memcpy(sm_persistent_ir, ir, 16); 4731 } 4732 4733 // Testing support only 4734 void sm_test_set_irk(sm_key_t irk){ 4735 (void)memcpy(sm_persistent_irk, irk, 16); 4736 dkg_state = DKG_CALC_DHK; 4737 test_use_fixed_local_irk = true; 4738 } 4739 4740 void sm_test_use_fixed_local_csrk(void){ 4741 test_use_fixed_local_csrk = true; 4742 } 4743 4744 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4745 static void sm_ec_generated(void * arg){ 4746 UNUSED(arg); 4747 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4748 // trigger pairing if pending for ec key 4749 sm_trigger_run(); 4750 } 4751 static void sm_ec_generate_new_key(void){ 4752 log_info("sm: generate new ec key"); 4753 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4754 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4755 } 4756 #endif 4757 4758 #ifdef ENABLE_TESTING_SUPPORT 4759 void sm_test_set_pairing_failure(int reason){ 4760 test_pairing_failure = reason; 4761 } 4762 #endif 4763 4764 static void sm_state_reset(void) { 4765 #ifdef USE_CMAC_ENGINE 4766 sm_cmac_active = 0; 4767 #endif 4768 dkg_state = DKG_W4_WORKING; 4769 rau_state = RAU_IDLE; 4770 sm_aes128_state = SM_AES128_IDLE; 4771 sm_address_resolution_test = -1; // no private address to resolve yet 4772 sm_address_resolution_ah_calculation_active = 0; 4773 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4774 sm_address_resolution_general_queue = NULL; 4775 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4776 sm_persistent_keys_random_active = false; 4777 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4778 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4779 #endif 4780 } 4781 4782 void sm_init(void){ 4783 4784 if (sm_initialized) return; 4785 4786 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4787 sm_er_ir_set_default(); 4788 4789 // defaults 4790 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4791 | SM_STK_GENERATION_METHOD_OOB 4792 | SM_STK_GENERATION_METHOD_PASSKEY 4793 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4794 4795 sm_max_encryption_key_size = 16; 4796 sm_min_encryption_key_size = 7; 4797 4798 sm_fixed_passkey_in_display_role = 0xffffffffU; 4799 sm_reconstruct_ltk_without_le_device_db_entry = true; 4800 4801 gap_random_adress_update_period = 15 * 60 * 1000L; 4802 4803 test_use_fixed_local_csrk = false; 4804 4805 // other 4806 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4807 4808 // register for HCI Events from HCI 4809 hci_event_callback_registration.callback = &sm_event_packet_handler; 4810 hci_add_event_handler(&hci_event_callback_registration); 4811 4812 // 4813 btstack_crypto_init(); 4814 4815 // init le_device_db 4816 le_device_db_init(); 4817 4818 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4819 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4820 4821 // state 4822 sm_state_reset(); 4823 4824 sm_initialized = true; 4825 } 4826 4827 void sm_deinit(void){ 4828 sm_initialized = false; 4829 btstack_run_loop_remove_timer(&sm_run_timer); 4830 } 4831 4832 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4833 sm_fixed_passkey_in_display_role = passkey; 4834 } 4835 4836 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4837 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4838 } 4839 4840 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4841 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4842 if (!hci_con) return NULL; 4843 return &hci_con->sm_connection; 4844 } 4845 4846 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4847 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4848 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4849 if (!hci_con) return NULL; 4850 return &hci_con->sm_connection; 4851 } 4852 #endif 4853 4854 // @deprecated: map onto sm_request_pairing 4855 void sm_send_security_request(hci_con_handle_t con_handle){ 4856 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4857 if (!sm_conn) return; 4858 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4859 sm_request_pairing(con_handle); 4860 } 4861 4862 // request pairing 4863 void sm_request_pairing(hci_con_handle_t con_handle){ 4864 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4865 if (!sm_conn) return; // wrong connection 4866 4867 bool have_ltk; 4868 uint8_t ltk[16]; 4869 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4870 if (IS_RESPONDER(sm_conn->sm_role)){ 4871 switch (sm_conn->sm_engine_state){ 4872 case SM_GENERAL_IDLE: 4873 case SM_RESPONDER_IDLE: 4874 switch (sm_conn->sm_irk_lookup_state){ 4875 case IRK_LOOKUP_SUCCEEDED: 4876 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4877 have_ltk = !sm_is_null_key(ltk); 4878 log_info("have ltk %u", have_ltk); 4879 if (have_ltk){ 4880 sm_conn->sm_pairing_requested = 1; 4881 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4882 sm_reencryption_started(sm_conn); 4883 break; 4884 } 4885 /* fall through */ 4886 4887 case IRK_LOOKUP_FAILED: 4888 sm_conn->sm_pairing_requested = 1; 4889 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4890 sm_pairing_started(sm_conn); 4891 break; 4892 default: 4893 log_info("irk lookup pending"); 4894 sm_conn->sm_pairing_requested = 1; 4895 break; 4896 } 4897 break; 4898 default: 4899 break; 4900 } 4901 } else { 4902 // used as a trigger to start central/master/initiator security procedures 4903 switch (sm_conn->sm_engine_state){ 4904 case SM_INITIATOR_CONNECTED: 4905 switch (sm_conn->sm_irk_lookup_state){ 4906 case IRK_LOOKUP_SUCCEEDED: 4907 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4908 have_ltk = !sm_is_null_key(ltk); 4909 log_info("have ltk %u", have_ltk); 4910 if (have_ltk){ 4911 sm_conn->sm_pairing_requested = 1; 4912 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4913 break; 4914 } 4915 /* fall through */ 4916 4917 case IRK_LOOKUP_FAILED: 4918 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4919 break; 4920 default: 4921 log_info("irk lookup pending"); 4922 sm_conn->sm_pairing_requested = 1; 4923 break; 4924 } 4925 break; 4926 case SM_GENERAL_REENCRYPTION_FAILED: 4927 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4928 break; 4929 case SM_GENERAL_IDLE: 4930 sm_conn->sm_pairing_requested = 1; 4931 break; 4932 default: 4933 break; 4934 } 4935 } 4936 sm_trigger_run(); 4937 } 4938 4939 // called by client app on authorization request 4940 void sm_authorization_decline(hci_con_handle_t con_handle){ 4941 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4942 if (!sm_conn) return; // wrong connection 4943 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4944 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4945 } 4946 4947 void sm_authorization_grant(hci_con_handle_t con_handle){ 4948 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4949 if (!sm_conn) return; // wrong connection 4950 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4951 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4952 } 4953 4954 // GAP Bonding API 4955 4956 void sm_bonding_decline(hci_con_handle_t con_handle){ 4957 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4958 if (!sm_conn) return; // wrong connection 4959 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4960 log_info("decline, state %u", sm_conn->sm_engine_state); 4961 switch(sm_conn->sm_engine_state){ 4962 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4963 case SM_SC_W4_USER_RESPONSE: 4964 case SM_SC_W4_CONFIRMATION: 4965 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4966 #endif 4967 case SM_PH1_W4_USER_RESPONSE: 4968 switch (setup->sm_stk_generation_method){ 4969 case PK_RESP_INPUT: 4970 case PK_INIT_INPUT: 4971 case PK_BOTH_INPUT: 4972 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4973 break; 4974 case NUMERIC_COMPARISON: 4975 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4976 break; 4977 case JUST_WORKS: 4978 case OOB: 4979 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4980 break; 4981 default: 4982 btstack_assert(false); 4983 break; 4984 } 4985 break; 4986 default: 4987 break; 4988 } 4989 sm_trigger_run(); 4990 } 4991 4992 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4993 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4994 if (!sm_conn) return; // wrong connection 4995 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4996 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4997 if (setup->sm_use_secure_connections){ 4998 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4999 } else { 5000 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); 5001 } 5002 } 5003 5004 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5005 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5006 sm_sc_prepare_dhkey_check(sm_conn); 5007 } 5008 #endif 5009 5010 sm_trigger_run(); 5011 } 5012 5013 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5014 // for now, it's the same 5015 sm_just_works_confirm(con_handle); 5016 } 5017 5018 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5019 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5020 if (!sm_conn) return; // wrong connection 5021 sm_reset_tk(); 5022 big_endian_store_32(setup->sm_tk, 12, passkey); 5023 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5024 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5025 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); 5026 } 5027 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5028 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5029 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5030 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5031 sm_sc_start_calculating_local_confirm(sm_conn); 5032 } 5033 #endif 5034 sm_trigger_run(); 5035 } 5036 5037 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5038 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5039 if (!sm_conn) return; // wrong connection 5040 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5041 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5042 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5043 switch (action){ 5044 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5045 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5046 flags |= (1u << action); 5047 break; 5048 case SM_KEYPRESS_PASSKEY_CLEARED: 5049 // clear counter, keypress & erased flags + set passkey cleared 5050 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5051 break; 5052 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5053 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 5054 // erase actions queued 5055 num_actions--; 5056 if (num_actions == 0u){ 5057 // clear counter, keypress & erased flags 5058 flags &= 0x19u; 5059 } 5060 break; 5061 } 5062 num_actions++; 5063 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5064 break; 5065 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5066 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5067 // enter actions queued 5068 num_actions--; 5069 if (num_actions == 0u){ 5070 // clear counter, keypress & erased flags 5071 flags &= 0x19u; 5072 } 5073 break; 5074 } 5075 num_actions++; 5076 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5077 break; 5078 default: 5079 break; 5080 } 5081 setup->sm_keypress_notification = (num_actions << 5) | flags; 5082 sm_trigger_run(); 5083 } 5084 5085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5086 static void sm_handle_random_result_oob(void * arg){ 5087 UNUSED(arg); 5088 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5089 sm_trigger_run(); 5090 } 5091 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5092 5093 static btstack_crypto_random_t sm_crypto_random_oob_request; 5094 5095 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5096 sm_sc_oob_callback = callback; 5097 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5098 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5099 return 0; 5100 } 5101 #endif 5102 5103 /** 5104 * @brief Get Identity Resolving state 5105 * @param con_handle 5106 * @return irk_lookup_state_t 5107 */ 5108 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5109 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5110 if (!sm_conn) return IRK_LOOKUP_IDLE; 5111 return sm_conn->sm_irk_lookup_state; 5112 } 5113 5114 /** 5115 * @brief Identify device in LE Device DB 5116 * @param handle 5117 * @return index from le_device_db or -1 if not found/identified 5118 */ 5119 int sm_le_device_index(hci_con_handle_t con_handle ){ 5120 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5121 if (!sm_conn) return -1; 5122 return sm_conn->sm_le_db_index; 5123 } 5124 5125 static int gap_random_address_type_requires_updates(void){ 5126 switch (gap_random_adress_type){ 5127 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5128 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5129 return 0; 5130 default: 5131 return 1; 5132 } 5133 } 5134 5135 static uint8_t own_address_type(void){ 5136 switch (gap_random_adress_type){ 5137 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5138 return BD_ADDR_TYPE_LE_PUBLIC; 5139 default: 5140 return BD_ADDR_TYPE_LE_RANDOM; 5141 } 5142 } 5143 5144 // GAP LE API 5145 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5146 gap_random_address_update_stop(); 5147 gap_random_adress_type = random_address_type; 5148 hci_le_set_own_address_type(own_address_type()); 5149 if (!gap_random_address_type_requires_updates()) return; 5150 gap_random_address_update_start(); 5151 gap_random_address_trigger(); 5152 } 5153 5154 gap_random_address_type_t gap_random_address_get_mode(void){ 5155 return gap_random_adress_type; 5156 } 5157 5158 void gap_random_address_set_update_period(int period_ms){ 5159 gap_random_adress_update_period = period_ms; 5160 if (!gap_random_address_type_requires_updates()) return; 5161 gap_random_address_update_stop(); 5162 gap_random_address_update_start(); 5163 } 5164 5165 void gap_random_address_set(const bd_addr_t addr){ 5166 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5167 (void)memcpy(sm_random_address, addr, 6); 5168 hci_le_random_address_set(addr); 5169 } 5170 5171 #ifdef ENABLE_LE_PERIPHERAL 5172 /* 5173 * @brief Set Advertisement Paramters 5174 * @param adv_int_min 5175 * @param adv_int_max 5176 * @param adv_type 5177 * @param direct_address_type 5178 * @param direct_address 5179 * @param channel_map 5180 * @param filter_policy 5181 * 5182 * @note own_address_type is used from gap_random_address_set_mode 5183 */ 5184 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5185 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5186 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5187 direct_address_typ, direct_address, channel_map, filter_policy); 5188 } 5189 #endif 5190 5191 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5192 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5193 // wrong connection 5194 if (!sm_conn) return 0; 5195 // already encrypted 5196 if (sm_conn->sm_connection_encrypted) return 0; 5197 // irk status? 5198 switch(sm_conn->sm_irk_lookup_state){ 5199 case IRK_LOOKUP_FAILED: 5200 // done, cannot setup encryption 5201 return 0; 5202 case IRK_LOOKUP_SUCCEEDED: 5203 break; 5204 default: 5205 // IR Lookup pending 5206 return 1; 5207 } 5208 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5209 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5210 if (sm_conn->sm_role){ 5211 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5212 } else { 5213 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5214 } 5215 } 5216 5217 void sm_set_secure_connections_only_mode(bool enable){ 5218 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5219 sm_sc_only_mode = enable; 5220 #else 5221 // SC Only mode not possible without support for SC 5222 btstack_assert(enable == false); 5223 #endif 5224 } 5225 5226 const uint8_t * gap_get_persistent_irk(void){ 5227 return sm_persistent_irk; 5228 } 5229 5230 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5231 uint16_t i; 5232 for (i=0; i < le_device_db_max_count(); i++){ 5233 bd_addr_t entry_address; 5234 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5235 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5236 // skip unused entries 5237 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5238 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5239 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 5240 hci_remove_le_device_db_entry_from_resolving_list(i); 5241 #endif 5242 le_device_db_remove(i); 5243 break; 5244 } 5245 } 5246 } 5247