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