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