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 // used in all phases 305 uint8_t sm_pairing_failed_reason; 306 307 // user response, (Phase 1 and/or 2) 308 uint8_t sm_user_response; 309 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 310 311 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 312 uint8_t sm_key_distribution_send_set; 313 uint8_t sm_key_distribution_sent_set; 314 uint8_t sm_key_distribution_received_set; 315 316 // Phase 2 (Pairing over SMP) 317 stk_generation_method_t sm_stk_generation_method; 318 sm_key_t sm_tk; 319 uint8_t sm_have_oob_data; 320 uint8_t sm_use_secure_connections; 321 322 sm_key_t sm_c1_t3_value; // c1 calculation 323 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 324 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 325 sm_key_t sm_local_random; 326 sm_key_t sm_local_confirm; 327 sm_key_t sm_peer_random; 328 sm_key_t sm_peer_confirm; 329 uint8_t sm_m_addr_type; // address and type can be removed 330 uint8_t sm_s_addr_type; // '' 331 bd_addr_t sm_m_address; // '' 332 bd_addr_t sm_s_address; // '' 333 sm_key_t sm_ltk; 334 335 uint8_t sm_state_vars; 336 #ifdef ENABLE_LE_SECURE_CONNECTIONS 337 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 338 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 339 sm_key_t sm_local_nonce; // might be combined with sm_local_random 340 uint8_t sm_dhkey[32]; 341 sm_key_t sm_peer_dhkey_check; 342 sm_key_t sm_local_dhkey_check; 343 sm_key_t sm_ra; 344 sm_key_t sm_rb; 345 sm_key_t sm_t; // used for f5 and h6 346 sm_key_t sm_mackey; 347 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 348 #endif 349 350 // Phase 3 351 352 // key distribution, we generate 353 uint16_t sm_local_y; 354 uint16_t sm_local_div; 355 uint16_t sm_local_ediv; 356 uint8_t sm_local_rand[8]; 357 sm_key_t sm_local_ltk; 358 sm_key_t sm_local_csrk; 359 sm_key_t sm_local_irk; 360 // sm_local_address/addr_type not needed 361 362 // key distribution, received from peer 363 uint16_t sm_peer_y; 364 uint16_t sm_peer_div; 365 uint16_t sm_peer_ediv; 366 uint8_t sm_peer_rand[8]; 367 sm_key_t sm_peer_ltk; 368 sm_key_t sm_peer_irk; 369 sm_key_t sm_peer_csrk; 370 uint8_t sm_peer_addr_type; 371 bd_addr_t sm_peer_address; 372 #ifdef ENABLE_LE_SIGNED_WRITE 373 int sm_le_device_index; 374 #endif 375 } sm_setup_context_t; 376 377 // 378 static sm_setup_context_t the_setup; 379 static sm_setup_context_t * setup = &the_setup; 380 381 // active connection - the one for which the_setup is used for 382 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 383 384 // @returns 1 if oob data is available 385 // stores oob data in provided 16 byte buffer if not null 386 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 387 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); 388 389 static void sm_run(void); 390 static void sm_done_for_handle(hci_con_handle_t con_handle); 391 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 392 static inline int sm_calc_actual_encryption_key_size(int other); 393 static int sm_validate_stk_generation_method(void); 394 static void sm_handle_encryption_result_address_resolution(void *arg); 395 static void sm_handle_encryption_result_dkg_dhk(void *arg); 396 static void sm_handle_encryption_result_dkg_irk(void *arg); 397 static void sm_handle_encryption_result_enc_a(void *arg); 398 static void sm_handle_encryption_result_enc_b(void *arg); 399 static void sm_handle_encryption_result_enc_c(void *arg); 400 static void sm_handle_encryption_result_enc_csrk(void *arg); 401 static void sm_handle_encryption_result_enc_d(void * arg); 402 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 403 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 404 #ifdef ENABLE_LE_PERIPHERAL 405 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 406 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 407 #endif 408 static void sm_handle_encryption_result_enc_stk(void *arg); 409 static void sm_handle_encryption_result_rau(void *arg); 410 static void sm_handle_random_result_ph2_tk(void * arg); 411 static void sm_handle_random_result_rau(void * arg); 412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 413 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)); 414 static void sm_ec_generate_new_key(void); 415 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 416 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 417 static int sm_passkey_entry(stk_generation_method_t method); 418 #endif 419 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 420 421 static void log_info_hex16(const char * name, uint16_t value){ 422 log_info("%-6s 0x%04x", name, value); 423 } 424 425 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 426 // return packet[0]; 427 // } 428 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 429 return packet[1]; 430 } 431 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 432 return packet[2]; 433 } 434 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 435 return packet[3]; 436 } 437 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 438 return packet[4]; 439 } 440 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 441 return packet[5]; 442 } 443 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 444 return packet[6]; 445 } 446 447 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 448 packet[0] = code; 449 } 450 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 451 packet[1] = io_capability; 452 } 453 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 454 packet[2] = oob_data_flag; 455 } 456 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 457 packet[3] = auth_req; 458 } 459 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 460 packet[4] = max_encryption_key_size; 461 } 462 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 463 packet[5] = initiator_key_distribution; 464 } 465 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 466 packet[6] = responder_key_distribution; 467 } 468 469 // @returns 1 if all bytes are 0 470 static bool sm_is_null(uint8_t * data, int size){ 471 int i; 472 for (i=0; i < size ; i++){ 473 if (data[i] != 0) { 474 return false; 475 } 476 } 477 return true; 478 } 479 480 static bool sm_is_null_random(uint8_t random[8]){ 481 return sm_is_null(random, 8); 482 } 483 484 static bool sm_is_null_key(uint8_t * key){ 485 return sm_is_null(key, 16); 486 } 487 488 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 489 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 490 UNUSED(ts); 491 sm_run(); 492 } 493 static void sm_trigger_run(void){ 494 if (!sm_initialized) return; 495 (void)btstack_run_loop_remove_timer(&sm_run_timer); 496 btstack_run_loop_set_timer(&sm_run_timer, 0); 497 btstack_run_loop_add_timer(&sm_run_timer); 498 } 499 500 // Key utils 501 static void sm_reset_tk(void){ 502 int i; 503 for (i=0;i<16;i++){ 504 setup->sm_tk[i] = 0; 505 } 506 } 507 508 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 509 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 510 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 511 int i; 512 for (i = max_encryption_size ; i < 16 ; i++){ 513 key[15-i] = 0; 514 } 515 } 516 517 // ER / IR checks 518 static void sm_er_ir_set_default(void){ 519 int i; 520 for (i=0;i<16;i++){ 521 sm_persistent_er[i] = 0x30 + i; 522 sm_persistent_ir[i] = 0x90 + i; 523 } 524 } 525 526 static int sm_er_is_default(void){ 527 int i; 528 for (i=0;i<16;i++){ 529 if (sm_persistent_er[i] != (0x30+i)) return 0; 530 } 531 return 1; 532 } 533 534 static int sm_ir_is_default(void){ 535 int i; 536 for (i=0;i<16;i++){ 537 if (sm_persistent_ir[i] != (0x90+i)) return 0; 538 } 539 return 1; 540 } 541 542 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 543 UNUSED(channel); 544 545 // log event 546 hci_dump_packet(packet_type, 1, packet, size); 547 // dispatch to all event handlers 548 btstack_linked_list_iterator_t it; 549 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 550 while (btstack_linked_list_iterator_has_next(&it)){ 551 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 552 entry->callback(packet_type, 0, packet, size); 553 } 554 } 555 556 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){ 557 event[0] = type; 558 event[1] = event_size - 2; 559 little_endian_store_16(event, 2, con_handle); 560 event[4] = addr_type; 561 reverse_bd_addr(address, &event[5]); 562 } 563 564 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 565 uint8_t event[11]; 566 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 567 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 568 } 569 570 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){ 571 uint8_t event[15]; 572 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 573 little_endian_store_32(event, 11, passkey); 574 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 575 } 576 577 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){ 578 // fetch addr and addr type from db, only called for valid entries 579 bd_addr_t identity_address; 580 int identity_address_type; 581 le_device_db_info(index, &identity_address_type, identity_address, NULL); 582 583 uint8_t event[20]; 584 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 585 event[11] = identity_address_type; 586 reverse_bd_addr(identity_address, &event[12]); 587 little_endian_store_16(event, 18, index); 588 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 589 } 590 591 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){ 592 uint8_t event[12]; 593 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 594 event[11] = status; 595 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 596 } 597 598 599 static void sm_reencryption_started(sm_connection_t * sm_conn){ 600 601 if (sm_conn->sm_reencryption_active) return; 602 603 sm_conn->sm_reencryption_active = true; 604 605 int identity_addr_type; 606 bd_addr_t identity_addr; 607 if (sm_conn->sm_le_db_index >= 0){ 608 // fetch addr and addr type from db, only called for valid entries 609 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 610 } else { 611 // for legacy pairing with LTK re-construction, use current peer addr 612 identity_addr_type = sm_conn->sm_peer_addr_type; 613 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 614 } 615 616 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 617 } 618 619 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 620 621 if (!sm_conn->sm_reencryption_active) return; 622 623 sm_conn->sm_reencryption_active = false; 624 625 int identity_addr_type; 626 bd_addr_t identity_addr; 627 if (sm_conn->sm_le_db_index >= 0){ 628 // fetch addr and addr type from db, only called for valid entries 629 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 630 } else { 631 // for legacy pairing with LTK re-construction, use current peer addr 632 identity_addr_type = sm_conn->sm_peer_addr_type; 633 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 634 } 635 636 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 637 } 638 639 static void sm_pairing_started(sm_connection_t * sm_conn){ 640 641 if (sm_conn->sm_pairing_active) return; 642 643 sm_conn->sm_pairing_active = true; 644 645 uint8_t event[11]; 646 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 647 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 648 } 649 650 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 651 652 if (!sm_conn->sm_pairing_active) return; 653 654 uint8_t event[13]; 655 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 656 event[11] = status; 657 event[12] = reason; 658 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 659 } 660 661 // SMP Timeout implementation 662 663 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 664 // the Security Manager Timer shall be reset and started. 665 // 666 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 667 // 668 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 669 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 670 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 671 // established. 672 673 static void sm_timeout_handler(btstack_timer_source_t * timer){ 674 log_info("SM timeout"); 675 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 676 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 677 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 678 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 679 sm_done_for_handle(sm_conn->sm_handle); 680 681 // trigger handling of next ready connection 682 sm_run(); 683 } 684 static void sm_timeout_start(sm_connection_t * sm_conn){ 685 btstack_run_loop_remove_timer(&setup->sm_timeout); 686 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 687 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 688 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 689 btstack_run_loop_add_timer(&setup->sm_timeout); 690 } 691 static void sm_timeout_stop(void){ 692 btstack_run_loop_remove_timer(&setup->sm_timeout); 693 } 694 static void sm_timeout_reset(sm_connection_t * sm_conn){ 695 sm_timeout_stop(); 696 sm_timeout_start(sm_conn); 697 } 698 699 // end of sm timeout 700 701 // GAP Random Address updates 702 static gap_random_address_type_t gap_random_adress_type; 703 static btstack_timer_source_t gap_random_address_update_timer; 704 static uint32_t gap_random_adress_update_period; 705 706 static void gap_random_address_trigger(void){ 707 log_info("gap_random_address_trigger, state %u", rau_state); 708 if (rau_state != RAU_IDLE) return; 709 rau_state = RAU_GET_RANDOM; 710 sm_trigger_run(); 711 } 712 713 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 714 UNUSED(timer); 715 716 log_info("GAP Random Address Update due"); 717 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 718 btstack_run_loop_add_timer(&gap_random_address_update_timer); 719 gap_random_address_trigger(); 720 } 721 722 static void gap_random_address_update_start(void){ 723 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 724 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 725 btstack_run_loop_add_timer(&gap_random_address_update_timer); 726 } 727 728 static void gap_random_address_update_stop(void){ 729 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 730 } 731 732 // ah(k,r) helper 733 // r = padding || r 734 // r - 24 bit value 735 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 736 // r'= padding || r 737 memset(r_prime, 0, 16); 738 (void)memcpy(&r_prime[13], r, 3); 739 } 740 741 // d1 helper 742 // d' = padding || r || d 743 // d,r - 16 bit values 744 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 745 // d'= padding || r || d 746 memset(d1_prime, 0, 16); 747 big_endian_store_16(d1_prime, 12, r); 748 big_endian_store_16(d1_prime, 14, d); 749 } 750 751 // calculate arguments for first AES128 operation in C1 function 752 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 753 754 // p1 = pres || preq || rat’ || iat’ 755 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 756 // cant octet of pres becomes the most significant octet of p1. 757 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 758 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 759 // p1 is 0x05000800000302070710000001010001." 760 761 sm_key_t p1; 762 reverse_56(pres, &p1[0]); 763 reverse_56(preq, &p1[7]); 764 p1[14] = rat; 765 p1[15] = iat; 766 log_info_key("p1", p1); 767 log_info_key("r", r); 768 769 // t1 = r xor p1 770 int i; 771 for (i=0;i<16;i++){ 772 t1[i] = r[i] ^ p1[i]; 773 } 774 log_info_key("t1", t1); 775 } 776 777 // calculate arguments for second AES128 operation in C1 function 778 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 779 // p2 = padding || ia || ra 780 // "The least significant octet of ra becomes the least significant octet of p2 and 781 // the most significant octet of padding becomes the most significant octet of p2. 782 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 783 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 784 785 sm_key_t p2; 786 memset(p2, 0, 16); 787 (void)memcpy(&p2[4], ia, 6); 788 (void)memcpy(&p2[10], ra, 6); 789 log_info_key("p2", p2); 790 791 // c1 = e(k, t2_xor_p2) 792 int i; 793 for (i=0;i<16;i++){ 794 t3[i] = t2[i] ^ p2[i]; 795 } 796 log_info_key("t3", t3); 797 } 798 799 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 800 log_info_key("r1", r1); 801 log_info_key("r2", r2); 802 (void)memcpy(&r_prime[8], &r2[8], 8); 803 (void)memcpy(&r_prime[0], &r1[8], 8); 804 } 805 806 807 // decide on stk generation based on 808 // - pairing request 809 // - io capabilities 810 // - OOB data availability 811 static void sm_setup_tk(void){ 812 813 // horizontal: initiator capabilities 814 // vertial: responder capabilities 815 static const stk_generation_method_t stk_generation_method [5] [5] = { 816 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 817 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 818 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 819 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 820 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 821 }; 822 823 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 824 #ifdef ENABLE_LE_SECURE_CONNECTIONS 825 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 826 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 827 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 828 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 829 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 830 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 831 }; 832 #endif 833 834 // default: just works 835 setup->sm_stk_generation_method = JUST_WORKS; 836 837 #ifdef ENABLE_LE_SECURE_CONNECTIONS 838 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 839 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 840 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 841 #else 842 setup->sm_use_secure_connections = 0; 843 #endif 844 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 845 846 847 // decide if OOB will be used based on SC vs. Legacy and oob flags 848 bool use_oob; 849 if (setup->sm_use_secure_connections){ 850 // In LE Secure Connections pairing, the out of band method is used if at least 851 // one device has the peer device's out of band authentication data available. 852 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 853 } else { 854 // In LE legacy pairing, the out of band method is used if both the devices have 855 // the other device's out of band authentication data available. 856 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 857 } 858 if (use_oob){ 859 log_info("SM: have OOB data"); 860 log_info_key("OOB", setup->sm_tk); 861 setup->sm_stk_generation_method = OOB; 862 return; 863 } 864 865 // If both devices have not set the MITM option in the Authentication Requirements 866 // Flags, then the IO capabilities shall be ignored and the Just Works association 867 // model shall be used. 868 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 869 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 870 log_info("SM: MITM not required by both -> JUST WORKS"); 871 return; 872 } 873 874 // Reset TK as it has been setup in sm_init_setup 875 sm_reset_tk(); 876 877 // Also use just works if unknown io capabilites 878 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 879 return; 880 } 881 882 // Otherwise the IO capabilities of the devices shall be used to determine the 883 // pairing method as defined in Table 2.4. 884 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 885 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 886 887 #ifdef ENABLE_LE_SECURE_CONNECTIONS 888 // table not define by default 889 if (setup->sm_use_secure_connections){ 890 generation_method = stk_generation_method_with_secure_connection; 891 } 892 #endif 893 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 894 895 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 896 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 897 } 898 899 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 900 int flags = 0; 901 if (key_set & SM_KEYDIST_ENC_KEY){ 902 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 903 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 904 } 905 if (key_set & SM_KEYDIST_ID_KEY){ 906 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 907 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 908 } 909 if (key_set & SM_KEYDIST_SIGN){ 910 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 911 } 912 return flags; 913 } 914 915 static void sm_setup_key_distribution(uint8_t key_set){ 916 setup->sm_key_distribution_received_set = 0; 917 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 918 setup->sm_key_distribution_sent_set = 0; 919 #ifdef ENABLE_LE_SIGNED_WRITE 920 setup->sm_le_device_index = -1; 921 #endif 922 } 923 924 // CSRK Key Lookup 925 926 927 static int sm_address_resolution_idle(void){ 928 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 929 } 930 931 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){ 932 (void)memcpy(sm_address_resolution_address, addr, 6); 933 sm_address_resolution_addr_type = addr_type; 934 sm_address_resolution_test = 0; 935 sm_address_resolution_mode = mode; 936 sm_address_resolution_context = context; 937 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 938 } 939 940 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 941 // check if already in list 942 btstack_linked_list_iterator_t it; 943 sm_lookup_entry_t * entry; 944 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 945 while(btstack_linked_list_iterator_has_next(&it)){ 946 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 947 if (entry->address_type != address_type) continue; 948 if (memcmp(entry->address, address, 6)) continue; 949 // already in list 950 return BTSTACK_BUSY; 951 } 952 entry = btstack_memory_sm_lookup_entry_get(); 953 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 954 entry->address_type = (bd_addr_type_t) address_type; 955 (void)memcpy(entry->address, address, 6); 956 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 957 sm_trigger_run(); 958 return 0; 959 } 960 961 // CMAC calculation using AES Engineq 962 #ifdef USE_CMAC_ENGINE 963 964 static void sm_cmac_done_trampoline(void * arg){ 965 UNUSED(arg); 966 sm_cmac_active = 0; 967 (*sm_cmac_done_callback)(sm_cmac_hash); 968 sm_trigger_run(); 969 } 970 971 int sm_cmac_ready(void){ 972 return sm_cmac_active == 0u; 973 } 974 #endif 975 976 #ifdef ENABLE_LE_SECURE_CONNECTIONS 977 // generic cmac calculation 978 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)){ 979 sm_cmac_active = 1; 980 sm_cmac_done_callback = done_callback; 981 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 982 } 983 #endif 984 985 // cmac for ATT Message signing 986 #ifdef ENABLE_LE_SIGNED_WRITE 987 988 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)){ 989 sm_cmac_active = 1; 990 sm_cmac_done_callback = done_callback; 991 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 992 } 993 994 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 995 if (offset >= sm_cmac_signed_write_message_len) { 996 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 997 return 0; 998 } 999 1000 offset = sm_cmac_signed_write_message_len - 1 - offset; 1001 1002 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1003 if (offset < 3){ 1004 return sm_cmac_signed_write_header[offset]; 1005 } 1006 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1007 if (offset < actual_message_len_incl_header){ 1008 return sm_cmac_signed_write_message[offset - 3]; 1009 } 1010 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1011 } 1012 1013 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)){ 1014 // ATT Message Signing 1015 sm_cmac_signed_write_header[0] = opcode; 1016 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1017 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1018 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1019 sm_cmac_signed_write_message = message; 1020 sm_cmac_signed_write_message_len = total_message_len; 1021 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1022 } 1023 #endif 1024 1025 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1026 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1027 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1028 sm_conn->sm_pairing_active = true; 1029 switch (setup->sm_stk_generation_method){ 1030 case PK_RESP_INPUT: 1031 if (IS_RESPONDER(sm_conn->sm_role)){ 1032 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1033 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1034 } else { 1035 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)); 1036 } 1037 break; 1038 case PK_INIT_INPUT: 1039 if (IS_RESPONDER(sm_conn->sm_role)){ 1040 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)); 1041 } else { 1042 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1043 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1044 } 1045 break; 1046 case PK_BOTH_INPUT: 1047 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1048 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1049 break; 1050 case NUMERIC_COMPARISON: 1051 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1052 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)); 1053 break; 1054 case JUST_WORKS: 1055 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1056 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1057 break; 1058 case OOB: 1059 // client already provided OOB data, let's skip notification. 1060 break; 1061 default: 1062 btstack_assert(false); 1063 break; 1064 } 1065 } 1066 1067 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1068 int recv_flags; 1069 if (IS_RESPONDER(sm_conn->sm_role)){ 1070 // slave / responder 1071 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1072 } else { 1073 // master / initiator 1074 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1075 } 1076 1077 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1078 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1079 if (setup->sm_use_secure_connections){ 1080 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1081 } 1082 #endif 1083 1084 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1085 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1086 } 1087 1088 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1089 if (sm_active_connection_handle == con_handle){ 1090 sm_timeout_stop(); 1091 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1092 log_info("sm: connection 0x%x released setup context", con_handle); 1093 1094 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1095 // generate new ec key after each pairing (that used it) 1096 if (setup->sm_use_secure_connections){ 1097 sm_ec_generate_new_key(); 1098 } 1099 #endif 1100 } 1101 } 1102 1103 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1104 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1105 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1106 sm_done_for_handle(connection->sm_handle); 1107 } 1108 1109 static int sm_key_distribution_flags_for_auth_req(void){ 1110 1111 int flags = SM_KEYDIST_ID_KEY; 1112 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1113 // encryption and signing information only if bonding requested 1114 flags |= SM_KEYDIST_ENC_KEY; 1115 #ifdef ENABLE_LE_SIGNED_WRITE 1116 flags |= SM_KEYDIST_SIGN; 1117 #endif 1118 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1119 // LinkKey for CTKD requires SC 1120 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1121 flags |= SM_KEYDIST_LINK_KEY; 1122 } 1123 #endif 1124 } 1125 return flags; 1126 } 1127 1128 static void sm_reset_setup(void){ 1129 // fill in sm setup 1130 setup->sm_state_vars = 0; 1131 setup->sm_keypress_notification = 0; 1132 sm_reset_tk(); 1133 } 1134 1135 static void sm_init_setup(sm_connection_t * sm_conn){ 1136 1137 // fill in sm setup 1138 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1139 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1140 1141 // query client for Legacy Pairing OOB data 1142 setup->sm_have_oob_data = 0; 1143 if (sm_get_oob_data != NULL) { 1144 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1145 } 1146 1147 // if available and SC supported, also ask for SC OOB Data 1148 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1149 memset(setup->sm_ra, 0, 16); 1150 memset(setup->sm_rb, 0, 16); 1151 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1152 if (sm_get_sc_oob_data != NULL){ 1153 if (IS_RESPONDER(sm_conn->sm_role)){ 1154 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1155 sm_conn->sm_peer_addr_type, 1156 sm_conn->sm_peer_address, 1157 setup->sm_peer_confirm, 1158 setup->sm_ra); 1159 } else { 1160 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1161 sm_conn->sm_peer_addr_type, 1162 sm_conn->sm_peer_address, 1163 setup->sm_peer_confirm, 1164 setup->sm_rb); 1165 } 1166 } else { 1167 setup->sm_have_oob_data = 0; 1168 } 1169 } 1170 #endif 1171 1172 sm_pairing_packet_t * local_packet; 1173 if (IS_RESPONDER(sm_conn->sm_role)){ 1174 // slave 1175 local_packet = &setup->sm_s_pres; 1176 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1177 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1178 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1179 } else { 1180 // master 1181 local_packet = &setup->sm_m_preq; 1182 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1183 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1184 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1185 1186 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1187 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1188 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1189 } 1190 1191 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1192 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1193 // set CT2 if SC + Bonding + CTKD 1194 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1195 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1196 auth_req |= SM_AUTHREQ_CT2; 1197 } 1198 #endif 1199 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1200 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1201 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1202 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1203 } 1204 1205 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1206 1207 sm_pairing_packet_t * remote_packet; 1208 int remote_key_request; 1209 if (IS_RESPONDER(sm_conn->sm_role)){ 1210 // slave / responder 1211 remote_packet = &setup->sm_m_preq; 1212 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1213 } else { 1214 // master / initiator 1215 remote_packet = &setup->sm_s_pres; 1216 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1217 } 1218 1219 // check key size 1220 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1221 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1222 1223 // decide on STK generation method / SC 1224 sm_setup_tk(); 1225 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1226 1227 // check if STK generation method is acceptable by client 1228 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1229 1230 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1231 // check LE SC Only mode 1232 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1233 log_info("SC Only mode active but SC not possible"); 1234 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1235 } 1236 1237 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1238 if (setup->sm_use_secure_connections){ 1239 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1240 } 1241 #endif 1242 1243 // identical to responder 1244 sm_setup_key_distribution(remote_key_request); 1245 1246 // JUST WORKS doens't provide authentication 1247 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1248 1249 return 0; 1250 } 1251 1252 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1253 1254 // cache and reset context 1255 int matched_device_id = sm_address_resolution_test; 1256 address_resolution_mode_t mode = sm_address_resolution_mode; 1257 void * context = sm_address_resolution_context; 1258 1259 // reset context 1260 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1261 sm_address_resolution_context = NULL; 1262 sm_address_resolution_test = -1; 1263 hci_con_handle_t con_handle = 0; 1264 1265 sm_connection_t * sm_connection; 1266 sm_key_t ltk; 1267 bool have_ltk; 1268 #ifdef ENABLE_LE_CENTRAL 1269 bool trigger_pairing; 1270 #endif 1271 switch (mode){ 1272 case ADDRESS_RESOLUTION_GENERAL: 1273 break; 1274 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1275 sm_connection = (sm_connection_t *) context; 1276 con_handle = sm_connection->sm_handle; 1277 1278 // have ltk -> start encryption / send security request 1279 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1280 // "When a bond has been created between two devices, any reconnection should result in the local device 1281 // enabling or requesting encryption with the remote device before initiating any service request." 1282 1283 switch (event){ 1284 case ADDRESS_RESOLUTION_SUCCEEDED: 1285 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1286 sm_connection->sm_le_db_index = matched_device_id; 1287 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1288 1289 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1290 have_ltk = !sm_is_null_key(ltk); 1291 1292 if (sm_connection->sm_role) { 1293 #ifdef ENABLE_LE_PERIPHERAL 1294 // IRK required before, continue 1295 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1296 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1297 break; 1298 } 1299 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1300 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1301 break; 1302 } 1303 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1304 sm_connection->sm_pairing_requested = 0; 1305 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1306 // trigger security request for Proactive Authentication if LTK available 1307 trigger_security_request = trigger_security_request || have_ltk; 1308 #endif 1309 1310 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1311 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1312 1313 if (trigger_security_request){ 1314 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1315 if (have_ltk){ 1316 sm_reencryption_started(sm_connection); 1317 } else { 1318 sm_pairing_started(sm_connection); 1319 } 1320 sm_trigger_run(); 1321 } 1322 #endif 1323 } else { 1324 1325 #ifdef ENABLE_LE_CENTRAL 1326 // check if pairing already requested and reset requests 1327 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1328 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1329 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1330 sm_connection->sm_security_request_received = 0; 1331 sm_connection->sm_pairing_requested = 0; 1332 bool trigger_reencryption = false; 1333 1334 if (have_ltk){ 1335 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1336 trigger_reencryption = true; 1337 #else 1338 if (trigger_pairing){ 1339 trigger_reencryption = true; 1340 } else { 1341 log_info("central: defer enabling encryption for bonded device"); 1342 } 1343 #endif 1344 } 1345 1346 if (trigger_reencryption){ 1347 log_info("central: enable encryption for bonded device"); 1348 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1349 break; 1350 } 1351 1352 // pairing_request -> send pairing request 1353 if (trigger_pairing){ 1354 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1355 break; 1356 } 1357 #endif 1358 } 1359 break; 1360 case ADDRESS_RESOLUTION_FAILED: 1361 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1362 if (sm_connection->sm_role) { 1363 #ifdef ENABLE_LE_PERIPHERAL 1364 // LTK request received before, IRK required -> negative LTK reply 1365 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1366 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1367 } 1368 // send security request if requested 1369 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1370 sm_connection->sm_pairing_requested = 0; 1371 if (trigger_security_request){ 1372 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1373 sm_pairing_started(sm_connection); 1374 } 1375 break; 1376 #endif 1377 } 1378 #ifdef ENABLE_LE_CENTRAL 1379 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1380 sm_connection->sm_security_request_received = 0; 1381 sm_connection->sm_pairing_requested = 0; 1382 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1383 #endif 1384 break; 1385 1386 default: 1387 btstack_assert(false); 1388 break; 1389 } 1390 break; 1391 default: 1392 break; 1393 } 1394 1395 switch (event){ 1396 case ADDRESS_RESOLUTION_SUCCEEDED: 1397 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1398 break; 1399 case ADDRESS_RESOLUTION_FAILED: 1400 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1401 break; 1402 default: 1403 btstack_assert(false); 1404 break; 1405 } 1406 } 1407 1408 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1409 1410 int le_db_index = -1; 1411 1412 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1413 bool bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1414 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1415 & SM_AUTHREQ_BONDING ) != 0u; 1416 1417 if (bonding_enabed){ 1418 1419 // lookup device based on IRK 1420 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1421 int i; 1422 for (i=0; i < le_device_db_max_count(); i++){ 1423 sm_key_t irk; 1424 bd_addr_t address; 1425 int address_type = BD_ADDR_TYPE_UNKNOWN; 1426 le_device_db_info(i, &address_type, address, irk); 1427 // skip unused entries 1428 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1429 // compare IRK 1430 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1431 1432 log_info("sm: device found for IRK, updating"); 1433 le_db_index = i; 1434 break; 1435 } 1436 } else { 1437 // assert IRK is set to zero 1438 memset(setup->sm_peer_irk, 0, 16); 1439 } 1440 1441 // if not found, lookup via public address if possible 1442 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1443 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1444 int i; 1445 for (i=0; i < le_device_db_max_count(); i++){ 1446 bd_addr_t address; 1447 int address_type = BD_ADDR_TYPE_UNKNOWN; 1448 le_device_db_info(i, &address_type, address, NULL); 1449 // skip unused entries 1450 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1451 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1452 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1453 log_info("sm: device found for public address, updating"); 1454 le_db_index = i; 1455 break; 1456 } 1457 } 1458 } 1459 1460 // if not found, add to db 1461 bool new_to_le_device_db = false; 1462 if (le_db_index < 0) { 1463 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1464 new_to_le_device_db = true; 1465 } 1466 1467 if (le_db_index >= 0){ 1468 1469 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1470 if (!new_to_le_device_db){ 1471 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1472 } 1473 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1474 #else 1475 UNUSED(new_to_le_device_db); 1476 #endif 1477 1478 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1479 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1480 1481 #ifdef ENABLE_LE_SIGNED_WRITE 1482 // store local CSRK 1483 setup->sm_le_device_index = le_db_index; 1484 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1485 log_info("sm: store local CSRK"); 1486 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1487 le_device_db_local_counter_set(le_db_index, 0); 1488 } 1489 1490 // store remote CSRK 1491 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1492 log_info("sm: store remote CSRK"); 1493 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1494 le_device_db_remote_counter_set(le_db_index, 0); 1495 } 1496 #endif 1497 // store encryption information for secure connections: LTK generated by ECDH 1498 if (setup->sm_use_secure_connections){ 1499 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1500 uint8_t zero_rand[8]; 1501 memset(zero_rand, 0, 8); 1502 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1503 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1504 } 1505 1506 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1507 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1508 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1509 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1510 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1511 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1512 1513 } 1514 } 1515 } else { 1516 log_info("Ignoring received keys, bonding not enabled"); 1517 } 1518 1519 // keep le_db_index 1520 sm_conn->sm_le_db_index = le_db_index; 1521 } 1522 1523 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1524 setup->sm_pairing_failed_reason = reason; 1525 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1526 } 1527 1528 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1529 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1530 } 1531 1532 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1533 1534 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1535 static int sm_passkey_used(stk_generation_method_t method); 1536 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1537 1538 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1539 if (setup->sm_stk_generation_method == OOB){ 1540 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1541 } else { 1542 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); 1543 } 1544 } 1545 1546 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1547 if (IS_RESPONDER(sm_conn->sm_role)){ 1548 // Responder 1549 if (setup->sm_stk_generation_method == OOB){ 1550 // generate Nb 1551 log_info("Generate Nb"); 1552 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); 1553 } else { 1554 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1555 } 1556 } else { 1557 // Initiator role 1558 switch (setup->sm_stk_generation_method){ 1559 case JUST_WORKS: 1560 sm_sc_prepare_dhkey_check(sm_conn); 1561 break; 1562 1563 case NUMERIC_COMPARISON: 1564 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1565 break; 1566 case PK_INIT_INPUT: 1567 case PK_RESP_INPUT: 1568 case PK_BOTH_INPUT: 1569 if (setup->sm_passkey_bit < 20u) { 1570 sm_sc_start_calculating_local_confirm(sm_conn); 1571 } else { 1572 sm_sc_prepare_dhkey_check(sm_conn); 1573 } 1574 break; 1575 case OOB: 1576 sm_sc_prepare_dhkey_check(sm_conn); 1577 break; 1578 default: 1579 btstack_assert(false); 1580 break; 1581 } 1582 } 1583 } 1584 1585 static void sm_sc_cmac_done(uint8_t * hash){ 1586 log_info("sm_sc_cmac_done: "); 1587 log_info_hexdump(hash, 16); 1588 1589 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1590 sm_sc_oob_state = SM_SC_OOB_IDLE; 1591 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1592 return; 1593 } 1594 1595 sm_connection_t * sm_conn = sm_cmac_connection; 1596 sm_cmac_connection = NULL; 1597 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1598 link_key_type_t link_key_type; 1599 #endif 1600 1601 switch (sm_conn->sm_engine_state){ 1602 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1603 (void)memcpy(setup->sm_local_confirm, hash, 16); 1604 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1605 break; 1606 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1607 // check 1608 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1609 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1610 break; 1611 } 1612 sm_sc_state_after_receiving_random(sm_conn); 1613 break; 1614 case SM_SC_W4_CALCULATE_G2: { 1615 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1616 big_endian_store_32(setup->sm_tk, 12, vab); 1617 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1618 sm_trigger_user_response(sm_conn); 1619 break; 1620 } 1621 case SM_SC_W4_CALCULATE_F5_SALT: 1622 (void)memcpy(setup->sm_t, hash, 16); 1623 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1624 break; 1625 case SM_SC_W4_CALCULATE_F5_MACKEY: 1626 (void)memcpy(setup->sm_mackey, hash, 16); 1627 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1628 break; 1629 case SM_SC_W4_CALCULATE_F5_LTK: 1630 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1631 // Errata Service Release to the Bluetooth Specification: ESR09 1632 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1633 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1634 (void)memcpy(setup->sm_ltk, hash, 16); 1635 (void)memcpy(setup->sm_local_ltk, hash, 16); 1636 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1637 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1638 break; 1639 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1640 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1641 if (IS_RESPONDER(sm_conn->sm_role)){ 1642 // responder 1643 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1644 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1645 } else { 1646 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1647 } 1648 } else { 1649 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1650 } 1651 break; 1652 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1653 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1654 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1655 break; 1656 } 1657 if (IS_RESPONDER(sm_conn->sm_role)){ 1658 // responder 1659 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1660 } else { 1661 // initiator 1662 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1663 } 1664 break; 1665 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1666 case SM_SC_W4_CALCULATE_ILK: 1667 (void)memcpy(setup->sm_t, hash, 16); 1668 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1669 break; 1670 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1671 reverse_128(hash, setup->sm_t); 1672 link_key_type = sm_conn->sm_connection_authenticated ? 1673 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1674 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1675 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1676 if (IS_RESPONDER(sm_conn->sm_role)){ 1677 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1678 } else { 1679 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1680 } 1681 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1682 sm_done_for_handle(sm_conn->sm_handle); 1683 break; 1684 #endif 1685 default: 1686 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1687 break; 1688 } 1689 sm_trigger_run(); 1690 } 1691 1692 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){ 1693 const uint16_t message_len = 65; 1694 sm_cmac_connection = sm_conn; 1695 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1696 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1697 sm_cmac_sc_buffer[64] = z; 1698 log_info("f4 key"); 1699 log_info_hexdump(x, 16); 1700 log_info("f4 message"); 1701 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1702 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1703 } 1704 1705 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1706 static const uint8_t f5_length[] = { 0x01, 0x00}; 1707 1708 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1709 1710 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1711 1712 log_info("f5_calculate_salt"); 1713 // calculate salt for f5 1714 const uint16_t message_len = 32; 1715 sm_cmac_connection = sm_conn; 1716 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1717 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1718 } 1719 1720 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){ 1721 const uint16_t message_len = 53; 1722 sm_cmac_connection = sm_conn; 1723 1724 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1725 sm_cmac_sc_buffer[0] = 0; 1726 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1727 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1728 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1729 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1730 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1731 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1732 log_info("f5 key"); 1733 log_info_hexdump(t, 16); 1734 log_info("f5 message for MacKey"); 1735 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1736 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1737 } 1738 1739 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1740 sm_key56_t bd_addr_master, bd_addr_slave; 1741 bd_addr_master[0] = setup->sm_m_addr_type; 1742 bd_addr_slave[0] = setup->sm_s_addr_type; 1743 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1744 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1745 if (IS_RESPONDER(sm_conn->sm_role)){ 1746 // responder 1747 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1748 } else { 1749 // initiator 1750 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1751 } 1752 } 1753 1754 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1755 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1756 const uint16_t message_len = 53; 1757 sm_cmac_connection = sm_conn; 1758 sm_cmac_sc_buffer[0] = 1; 1759 // 1..52 setup before 1760 log_info("f5 key"); 1761 log_info_hexdump(t, 16); 1762 log_info("f5 message for LTK"); 1763 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1764 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1765 } 1766 1767 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1768 f5_ltk(sm_conn, setup->sm_t); 1769 } 1770 1771 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){ 1772 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1773 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1774 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1775 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1776 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1777 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1778 } 1779 1780 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1781 const uint16_t message_len = 65; 1782 sm_cmac_connection = sm_conn; 1783 log_info("f6 key"); 1784 log_info_hexdump(w, 16); 1785 log_info("f6 message"); 1786 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1787 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1788 } 1789 1790 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1791 // - U is 256 bits 1792 // - V is 256 bits 1793 // - X is 128 bits 1794 // - Y is 128 bits 1795 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){ 1796 const uint16_t message_len = 80; 1797 sm_cmac_connection = sm_conn; 1798 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1799 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1800 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1801 log_info("g2 key"); 1802 log_info_hexdump(x, 16); 1803 log_info("g2 message"); 1804 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1805 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1806 } 1807 1808 static void g2_calculate(sm_connection_t * sm_conn) { 1809 // calc Va if numeric comparison 1810 if (IS_RESPONDER(sm_conn->sm_role)){ 1811 // responder 1812 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1813 } else { 1814 // initiator 1815 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1816 } 1817 } 1818 1819 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1820 uint8_t z = 0; 1821 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1822 // some form of passkey 1823 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1824 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1825 setup->sm_passkey_bit++; 1826 } 1827 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1828 } 1829 1830 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1831 // OOB 1832 if (setup->sm_stk_generation_method == OOB){ 1833 if (IS_RESPONDER(sm_conn->sm_role)){ 1834 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1835 } else { 1836 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1837 } 1838 return; 1839 } 1840 1841 uint8_t z = 0; 1842 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1843 // some form of passkey 1844 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1845 // sm_passkey_bit was increased before sending confirm value 1846 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1847 } 1848 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1849 } 1850 1851 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1852 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1853 1854 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1855 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1856 return; 1857 } else { 1858 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1859 } 1860 } 1861 1862 static void sm_sc_dhkey_calculated(void * arg){ 1863 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1864 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1865 if (sm_conn == NULL) return; 1866 1867 log_info("dhkey"); 1868 log_info_hexdump(&setup->sm_dhkey[0], 32); 1869 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1870 // trigger next step 1871 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1872 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1873 } 1874 sm_trigger_run(); 1875 } 1876 1877 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1878 // calculate DHKCheck 1879 sm_key56_t bd_addr_master, bd_addr_slave; 1880 bd_addr_master[0] = setup->sm_m_addr_type; 1881 bd_addr_slave[0] = setup->sm_s_addr_type; 1882 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1883 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1884 uint8_t iocap_a[3]; 1885 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1886 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1887 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1888 uint8_t iocap_b[3]; 1889 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1890 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1891 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1892 if (IS_RESPONDER(sm_conn->sm_role)){ 1893 // responder 1894 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1895 f6_engine(sm_conn, setup->sm_mackey); 1896 } else { 1897 // initiator 1898 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1899 f6_engine(sm_conn, setup->sm_mackey); 1900 } 1901 } 1902 1903 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1904 // validate E = f6() 1905 sm_key56_t bd_addr_master, bd_addr_slave; 1906 bd_addr_master[0] = setup->sm_m_addr_type; 1907 bd_addr_slave[0] = setup->sm_s_addr_type; 1908 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1909 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1910 1911 uint8_t iocap_a[3]; 1912 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1913 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1914 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1915 uint8_t iocap_b[3]; 1916 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1917 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1918 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1919 if (IS_RESPONDER(sm_conn->sm_role)){ 1920 // responder 1921 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1922 f6_engine(sm_conn, setup->sm_mackey); 1923 } else { 1924 // initiator 1925 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1926 f6_engine(sm_conn, setup->sm_mackey); 1927 } 1928 } 1929 1930 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1931 1932 // 1933 // Link Key Conversion Function h6 1934 // 1935 // h6(W, keyID) = AES-CMAC_W(keyID) 1936 // - W is 128 bits 1937 // - keyID is 32 bits 1938 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1939 const uint16_t message_len = 4; 1940 sm_cmac_connection = sm_conn; 1941 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1942 log_info("h6 key"); 1943 log_info_hexdump(w, 16); 1944 log_info("h6 message"); 1945 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1946 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1947 } 1948 // 1949 // Link Key Conversion Function h7 1950 // 1951 // h7(SALT, W) = AES-CMAC_SALT(W) 1952 // - SALT is 128 bits 1953 // - W is 128 bits 1954 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1955 const uint16_t message_len = 16; 1956 sm_cmac_connection = sm_conn; 1957 log_info("h7 key"); 1958 log_info_hexdump(salt, 16); 1959 log_info("h7 message"); 1960 log_info_hexdump(w, 16); 1961 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1962 } 1963 1964 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1965 // Errata Service Release to the Bluetooth Specification: ESR09 1966 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1967 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1968 1969 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1970 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1971 } 1972 1973 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1974 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1975 } 1976 1977 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1978 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1979 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1980 } 1981 #endif 1982 1983 #endif 1984 1985 // key management legacy connections: 1986 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1987 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1988 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1989 // - responder reconnects: responder uses LTK receveived from master 1990 1991 // key management secure connections: 1992 // - both devices store same LTK from ECDH key exchange. 1993 1994 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1995 static void sm_load_security_info(sm_connection_t * sm_connection){ 1996 int encryption_key_size; 1997 int authenticated; 1998 int authorized; 1999 int secure_connection; 2000 2001 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2002 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2003 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2004 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); 2005 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2006 sm_connection->sm_connection_authenticated = authenticated; 2007 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2008 sm_connection->sm_connection_sc = secure_connection; 2009 } 2010 #endif 2011 2012 #ifdef ENABLE_LE_PERIPHERAL 2013 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2014 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2015 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2016 // re-establish used key encryption size 2017 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2018 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2019 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2020 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2021 // Legacy paring -> not SC 2022 sm_connection->sm_connection_sc = 0; 2023 log_info("sm: received ltk request with key size %u, authenticated %u", 2024 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2025 } 2026 #endif 2027 2028 // distributed key generation 2029 static bool sm_run_dpkg(void){ 2030 switch (dkg_state){ 2031 case DKG_CALC_IRK: 2032 // already busy? 2033 if (sm_aes128_state == SM_AES128_IDLE) { 2034 log_info("DKG_CALC_IRK started"); 2035 // IRK = d1(IR, 1, 0) 2036 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2037 sm_aes128_state = SM_AES128_ACTIVE; 2038 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2039 return true; 2040 } 2041 break; 2042 case DKG_CALC_DHK: 2043 // already busy? 2044 if (sm_aes128_state == SM_AES128_IDLE) { 2045 log_info("DKG_CALC_DHK started"); 2046 // DHK = d1(IR, 3, 0) 2047 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2048 sm_aes128_state = SM_AES128_ACTIVE; 2049 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2050 return true; 2051 } 2052 break; 2053 default: 2054 break; 2055 } 2056 return false; 2057 } 2058 2059 // random address updates 2060 static bool sm_run_rau(void){ 2061 switch (rau_state){ 2062 case RAU_GET_RANDOM: 2063 rau_state = RAU_W4_RANDOM; 2064 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2065 return true; 2066 case RAU_GET_ENC: 2067 // already busy? 2068 if (sm_aes128_state == SM_AES128_IDLE) { 2069 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2070 sm_aes128_state = SM_AES128_ACTIVE; 2071 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2072 return true; 2073 } 2074 break; 2075 case RAU_SET_ADDRESS: 2076 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2077 rau_state = RAU_IDLE; 2078 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2079 return true; 2080 default: 2081 break; 2082 } 2083 return false; 2084 } 2085 2086 // CSRK Lookup 2087 static bool sm_run_csrk(void){ 2088 btstack_linked_list_iterator_t it; 2089 2090 // -- if csrk lookup ready, find connection that require csrk lookup 2091 if (sm_address_resolution_idle()){ 2092 hci_connections_get_iterator(&it); 2093 while(btstack_linked_list_iterator_has_next(&it)){ 2094 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2095 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2096 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2097 // and start lookup 2098 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); 2099 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2100 break; 2101 } 2102 } 2103 } 2104 2105 // -- if csrk lookup ready, resolved addresses for received addresses 2106 if (sm_address_resolution_idle()) { 2107 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2108 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2109 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2110 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2111 btstack_memory_sm_lookup_entry_free(entry); 2112 } 2113 } 2114 2115 // -- Continue with CSRK device lookup by public or resolvable private address 2116 if (!sm_address_resolution_idle()){ 2117 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2118 while (sm_address_resolution_test < le_device_db_max_count()){ 2119 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2120 bd_addr_t addr; 2121 sm_key_t irk; 2122 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2123 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2124 2125 // skip unused entries 2126 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2127 sm_address_resolution_test++; 2128 continue; 2129 } 2130 2131 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2132 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2133 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2134 break; 2135 } 2136 2137 // if connection type is public, it must be a different one 2138 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2139 sm_address_resolution_test++; 2140 continue; 2141 } 2142 2143 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2144 2145 log_info("LE Device Lookup: calculate AH"); 2146 log_info_key("IRK", irk); 2147 2148 (void)memcpy(sm_aes128_key, irk, 16); 2149 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2150 sm_address_resolution_ah_calculation_active = 1; 2151 sm_aes128_state = SM_AES128_ACTIVE; 2152 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2153 return true; 2154 } 2155 2156 if (sm_address_resolution_test >= le_device_db_max_count()){ 2157 log_info("LE Device Lookup: not found"); 2158 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2159 } 2160 } 2161 return false; 2162 } 2163 2164 // SC OOB 2165 static bool sm_run_oob(void){ 2166 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2167 switch (sm_sc_oob_state){ 2168 case SM_SC_OOB_W2_CALC_CONFIRM: 2169 if (!sm_cmac_ready()) break; 2170 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2171 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2172 return true; 2173 default: 2174 break; 2175 } 2176 #endif 2177 return false; 2178 } 2179 2180 // handle basic actions that don't requires the full context 2181 static bool sm_run_basic(void){ 2182 btstack_linked_list_iterator_t it; 2183 hci_connections_get_iterator(&it); 2184 while(btstack_linked_list_iterator_has_next(&it)){ 2185 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2186 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2187 switch(sm_connection->sm_engine_state){ 2188 // responder side 2189 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2190 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2191 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2192 return true; 2193 2194 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2195 case SM_SC_RECEIVED_LTK_REQUEST: 2196 switch (sm_connection->sm_irk_lookup_state){ 2197 case IRK_LOOKUP_FAILED: 2198 log_info("LTK Request: IRK Lookup Failed)"); 2199 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2200 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2201 return true; 2202 default: 2203 break; 2204 } 2205 break; 2206 #endif 2207 default: 2208 break; 2209 } 2210 } 2211 return false; 2212 } 2213 2214 static void sm_run_activate_connection(void){ 2215 // Find connections that requires setup context and make active if no other is locked 2216 btstack_linked_list_iterator_t it; 2217 hci_connections_get_iterator(&it); 2218 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2219 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2220 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2221 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2222 bool done = true; 2223 int err; 2224 UNUSED(err); 2225 2226 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2227 // assert ec key is ready 2228 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2229 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2230 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2231 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2232 sm_ec_generate_new_key(); 2233 } 2234 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2235 continue; 2236 } 2237 } 2238 #endif 2239 2240 switch (sm_connection->sm_engine_state) { 2241 #ifdef ENABLE_LE_PERIPHERAL 2242 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2243 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2244 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2246 case SM_SC_RECEIVED_LTK_REQUEST: 2247 #endif 2248 #endif 2249 #ifdef ENABLE_LE_CENTRAL 2250 case SM_INITIATOR_PH4_HAS_LTK: 2251 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2252 #endif 2253 // just lock context 2254 break; 2255 default: 2256 done = false; 2257 break; 2258 } 2259 if (done){ 2260 sm_active_connection_handle = sm_connection->sm_handle; 2261 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); 2262 } 2263 } 2264 } 2265 2266 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2267 int i; 2268 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2269 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2270 uint8_t action = 0; 2271 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2272 if (flags & (1u<<i)){ 2273 bool clear_flag = true; 2274 switch (i){ 2275 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2276 case SM_KEYPRESS_PASSKEY_CLEARED: 2277 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2278 default: 2279 break; 2280 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2281 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2282 num_actions--; 2283 clear_flag = num_actions == 0u; 2284 break; 2285 } 2286 if (clear_flag){ 2287 flags &= ~(1<<i); 2288 } 2289 action = i; 2290 break; 2291 } 2292 } 2293 setup->sm_keypress_notification = (num_actions << 5) | flags; 2294 2295 // send keypress notification 2296 uint8_t buffer[2]; 2297 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2298 buffer[1] = action; 2299 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2300 2301 // try 2302 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2303 } 2304 2305 static void sm_run_distribute_keys(sm_connection_t * connection){ 2306 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2307 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2308 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2309 uint8_t buffer[17]; 2310 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2311 reverse_128(setup->sm_ltk, &buffer[1]); 2312 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2313 sm_timeout_reset(connection); 2314 return; 2315 } 2316 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2317 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2318 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2319 uint8_t buffer[11]; 2320 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2321 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2322 reverse_64(setup->sm_local_rand, &buffer[3]); 2323 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2324 sm_timeout_reset(connection); 2325 return; 2326 } 2327 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2328 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2329 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2330 uint8_t buffer[17]; 2331 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2332 reverse_128(sm_persistent_irk, &buffer[1]); 2333 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2334 sm_timeout_reset(connection); 2335 return; 2336 } 2337 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2338 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2339 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2340 bd_addr_t local_address; 2341 uint8_t buffer[8]; 2342 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2343 switch (gap_random_address_get_mode()){ 2344 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2345 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2346 // public or static random 2347 gap_le_get_own_address(&buffer[1], local_address); 2348 break; 2349 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2350 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2351 // fallback to public 2352 gap_local_bd_addr(local_address); 2353 buffer[1] = 0; 2354 break; 2355 default: 2356 btstack_assert(false); 2357 break; 2358 } 2359 reverse_bd_addr(local_address, &buffer[2]); 2360 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2361 sm_timeout_reset(connection); 2362 return; 2363 } 2364 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2365 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2366 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2367 2368 #ifdef ENABLE_LE_SIGNED_WRITE 2369 // hack to reproduce test runs 2370 if (test_use_fixed_local_csrk){ 2371 memset(setup->sm_local_csrk, 0xcc, 16); 2372 } 2373 2374 // store local CSRK 2375 if (setup->sm_le_device_index >= 0){ 2376 log_info("sm: store local CSRK"); 2377 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2378 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2379 } 2380 #endif 2381 2382 uint8_t buffer[17]; 2383 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2384 reverse_128(setup->sm_local_csrk, &buffer[1]); 2385 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2386 sm_timeout_reset(connection); 2387 return; 2388 } 2389 btstack_assert(false); 2390 } 2391 2392 static void sm_run(void){ 2393 2394 // assert that stack has already bootet 2395 if (hci_get_state() != HCI_STATE_WORKING) return; 2396 2397 // assert that we can send at least commands 2398 if (!hci_can_send_command_packet_now()) return; 2399 2400 // pause until IR/ER are ready 2401 if (sm_persistent_keys_random_active) return; 2402 2403 bool done; 2404 2405 // 2406 // non-connection related behaviour 2407 // 2408 2409 done = sm_run_dpkg(); 2410 if (done) return; 2411 2412 done = sm_run_rau(); 2413 if (done) return; 2414 2415 done = sm_run_csrk(); 2416 if (done) return; 2417 2418 done = sm_run_oob(); 2419 if (done) return; 2420 2421 // assert that we can send at least commands - cmd might have been sent by crypto engine 2422 if (!hci_can_send_command_packet_now()) return; 2423 2424 // handle basic actions that don't requires the full context 2425 done = sm_run_basic(); 2426 if (done) return; 2427 2428 // 2429 // active connection handling 2430 // -- use loop to handle next connection if lock on setup context is released 2431 2432 while (true) { 2433 2434 sm_run_activate_connection(); 2435 2436 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2437 2438 // 2439 // active connection handling 2440 // 2441 2442 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2443 if (!connection) { 2444 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2445 return; 2446 } 2447 2448 // assert that we could send a SM PDU - not needed for all of the following 2449 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2450 log_info("cannot send now, requesting can send now event"); 2451 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2452 return; 2453 } 2454 2455 // send keypress notifications 2456 if (setup->sm_keypress_notification){ 2457 sm_run_send_keypress_notification(connection); 2458 return; 2459 } 2460 2461 int key_distribution_flags; 2462 UNUSED(key_distribution_flags); 2463 int err; 2464 UNUSED(err); 2465 bool have_ltk; 2466 uint8_t ltk[16]; 2467 2468 log_info("sm_run: state %u", connection->sm_engine_state); 2469 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2470 log_info("sm_run // cannot send"); 2471 } 2472 switch (connection->sm_engine_state){ 2473 2474 // general 2475 case SM_GENERAL_SEND_PAIRING_FAILED: { 2476 uint8_t buffer[2]; 2477 buffer[0] = SM_CODE_PAIRING_FAILED; 2478 buffer[1] = setup->sm_pairing_failed_reason; 2479 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2480 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2481 sm_pairing_complete(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2482 sm_done_for_handle(connection->sm_handle); 2483 break; 2484 } 2485 2486 // secure connections, initiator + responding states 2487 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2488 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2489 if (!sm_cmac_ready()) break; 2490 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2491 sm_sc_calculate_local_confirm(connection); 2492 break; 2493 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2494 if (!sm_cmac_ready()) break; 2495 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2496 sm_sc_calculate_remote_confirm(connection); 2497 break; 2498 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2499 if (!sm_cmac_ready()) break; 2500 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2501 sm_sc_calculate_f6_for_dhkey_check(connection); 2502 break; 2503 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2504 if (!sm_cmac_ready()) break; 2505 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2506 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2507 break; 2508 case SM_SC_W2_CALCULATE_F5_SALT: 2509 if (!sm_cmac_ready()) break; 2510 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2511 f5_calculate_salt(connection); 2512 break; 2513 case SM_SC_W2_CALCULATE_F5_MACKEY: 2514 if (!sm_cmac_ready()) break; 2515 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2516 f5_calculate_mackey(connection); 2517 break; 2518 case SM_SC_W2_CALCULATE_F5_LTK: 2519 if (!sm_cmac_ready()) break; 2520 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2521 f5_calculate_ltk(connection); 2522 break; 2523 case SM_SC_W2_CALCULATE_G2: 2524 if (!sm_cmac_ready()) break; 2525 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2526 g2_calculate(connection); 2527 break; 2528 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2529 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2530 if (!sm_cmac_ready()) break; 2531 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2532 h6_calculate_ilk(connection); 2533 break; 2534 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2535 if (!sm_cmac_ready()) break; 2536 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2537 h6_calculate_br_edr_link_key(connection); 2538 break; 2539 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2540 if (!sm_cmac_ready()) break; 2541 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2542 h7_calculate_ilk(connection); 2543 break; 2544 #endif 2545 #endif 2546 2547 #ifdef ENABLE_LE_CENTRAL 2548 // initiator side 2549 2550 case SM_INITIATOR_PH4_HAS_LTK: { 2551 sm_reset_setup(); 2552 sm_load_security_info(connection); 2553 sm_reencryption_started(connection); 2554 2555 sm_key_t peer_ltk_flipped; 2556 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2557 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2558 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2559 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2560 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2561 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2562 return; 2563 } 2564 2565 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2566 sm_reset_setup(); 2567 sm_init_setup(connection); 2568 sm_timeout_start(connection); 2569 sm_pairing_started(connection); 2570 2571 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2572 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2573 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2574 sm_timeout_reset(connection); 2575 break; 2576 #endif 2577 2578 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2579 2580 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2581 bool trigger_user_response = false; 2582 bool trigger_start_calculating_local_confirm = false; 2583 uint8_t buffer[65]; 2584 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2585 // 2586 reverse_256(&ec_q[0], &buffer[1]); 2587 reverse_256(&ec_q[32], &buffer[33]); 2588 2589 #ifdef ENABLE_TESTING_SUPPORT 2590 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2591 log_info("testing_support: invalidating public key"); 2592 // flip single bit of public key coordinate 2593 buffer[1] ^= 1; 2594 } 2595 #endif 2596 2597 // stk generation method 2598 // passkey entry: notify app to show passkey or to request passkey 2599 switch (setup->sm_stk_generation_method){ 2600 case JUST_WORKS: 2601 case NUMERIC_COMPARISON: 2602 if (IS_RESPONDER(connection->sm_role)){ 2603 // responder 2604 trigger_start_calculating_local_confirm = true; 2605 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2606 } else { 2607 // initiator 2608 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2609 } 2610 break; 2611 case PK_INIT_INPUT: 2612 case PK_RESP_INPUT: 2613 case PK_BOTH_INPUT: 2614 // use random TK for display 2615 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2616 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2617 setup->sm_passkey_bit = 0; 2618 2619 if (IS_RESPONDER(connection->sm_role)){ 2620 // responder 2621 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2622 } else { 2623 // initiator 2624 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2625 } 2626 trigger_user_response = true; 2627 break; 2628 case OOB: 2629 if (IS_RESPONDER(connection->sm_role)){ 2630 // responder 2631 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2632 } else { 2633 // initiator 2634 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2635 } 2636 break; 2637 default: 2638 btstack_assert(false); 2639 break; 2640 } 2641 2642 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2643 sm_timeout_reset(connection); 2644 2645 // trigger user response and calc confirm after sending pdu 2646 if (trigger_user_response){ 2647 sm_trigger_user_response(connection); 2648 } 2649 if (trigger_start_calculating_local_confirm){ 2650 sm_sc_start_calculating_local_confirm(connection); 2651 } 2652 break; 2653 } 2654 case SM_SC_SEND_CONFIRMATION: { 2655 uint8_t buffer[17]; 2656 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2657 reverse_128(setup->sm_local_confirm, &buffer[1]); 2658 if (IS_RESPONDER(connection->sm_role)){ 2659 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2660 } else { 2661 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2662 } 2663 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2664 sm_timeout_reset(connection); 2665 break; 2666 } 2667 case SM_SC_SEND_PAIRING_RANDOM: { 2668 uint8_t buffer[17]; 2669 buffer[0] = SM_CODE_PAIRING_RANDOM; 2670 reverse_128(setup->sm_local_nonce, &buffer[1]); 2671 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2672 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2673 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2674 if (IS_RESPONDER(connection->sm_role)){ 2675 // responder 2676 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2677 } else { 2678 // initiator 2679 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2680 } 2681 } else { 2682 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2683 if (IS_RESPONDER(connection->sm_role)){ 2684 // responder 2685 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2686 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2687 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2688 } else { 2689 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2690 sm_sc_prepare_dhkey_check(connection); 2691 } 2692 } else { 2693 // initiator 2694 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2695 } 2696 } 2697 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2698 sm_timeout_reset(connection); 2699 break; 2700 } 2701 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2702 uint8_t buffer[17]; 2703 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2704 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2705 2706 if (IS_RESPONDER(connection->sm_role)){ 2707 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2708 } else { 2709 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2710 } 2711 2712 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2713 sm_timeout_reset(connection); 2714 break; 2715 } 2716 2717 #endif 2718 2719 #ifdef ENABLE_LE_PERIPHERAL 2720 2721 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2722 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2723 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2724 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2725 sm_timeout_start(connection); 2726 break; 2727 } 2728 2729 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2730 case SM_SC_RECEIVED_LTK_REQUEST: 2731 switch (connection->sm_irk_lookup_state){ 2732 case IRK_LOOKUP_SUCCEEDED: 2733 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2734 // start using context by loading security info 2735 sm_reset_setup(); 2736 sm_load_security_info(connection); 2737 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2738 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2739 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2740 sm_reencryption_started(connection); 2741 sm_trigger_run(); 2742 break; 2743 } 2744 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2745 connection->sm_engine_state = SM_RESPONDER_IDLE; 2746 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2747 return; 2748 default: 2749 // just wait until IRK lookup is completed 2750 break; 2751 } 2752 break; 2753 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2754 2755 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2756 sm_reset_setup(); 2757 2758 // handle Pairing Request with LTK available 2759 switch (connection->sm_irk_lookup_state) { 2760 case IRK_LOOKUP_SUCCEEDED: 2761 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2762 have_ltk = !sm_is_null_key(ltk); 2763 if (have_ltk){ 2764 log_info("pairing request but LTK available"); 2765 // emit re-encryption start/fail sequence 2766 sm_reencryption_started(connection); 2767 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2768 } 2769 break; 2770 default: 2771 break; 2772 } 2773 2774 sm_init_setup(connection); 2775 sm_pairing_started(connection); 2776 2777 // recover pairing request 2778 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2779 err = sm_stk_generation_init(connection); 2780 2781 #ifdef ENABLE_TESTING_SUPPORT 2782 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2783 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2784 err = test_pairing_failure; 2785 } 2786 #endif 2787 if (err != 0){ 2788 setup->sm_pairing_failed_reason = err; 2789 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2790 sm_trigger_run(); 2791 break; 2792 } 2793 2794 sm_timeout_start(connection); 2795 2796 // generate random number first, if we need to show passkey, otherwise send response 2797 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2798 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2799 break; 2800 } 2801 2802 /* fall through */ 2803 2804 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2805 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2806 2807 // start with initiator key dist flags 2808 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2809 2810 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2811 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2812 if (setup->sm_use_secure_connections){ 2813 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2814 } 2815 #endif 2816 // setup in response 2817 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); 2818 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); 2819 2820 // update key distribution after ENC was dropped 2821 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2822 2823 if (setup->sm_use_secure_connections){ 2824 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2825 } else { 2826 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2827 } 2828 2829 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2830 sm_timeout_reset(connection); 2831 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2832 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2833 sm_trigger_user_response(connection); 2834 } 2835 return; 2836 #endif 2837 2838 case SM_PH2_SEND_PAIRING_RANDOM: { 2839 uint8_t buffer[17]; 2840 buffer[0] = SM_CODE_PAIRING_RANDOM; 2841 reverse_128(setup->sm_local_random, &buffer[1]); 2842 if (IS_RESPONDER(connection->sm_role)){ 2843 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2844 } else { 2845 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2846 } 2847 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2848 sm_timeout_reset(connection); 2849 break; 2850 } 2851 2852 case SM_PH2_C1_GET_ENC_A: 2853 // already busy? 2854 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2855 // calculate confirm using aes128 engine - step 1 2856 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); 2857 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2858 sm_aes128_state = SM_AES128_ACTIVE; 2859 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); 2860 break; 2861 2862 case SM_PH2_C1_GET_ENC_C: 2863 // already busy? 2864 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2865 // calculate m_confirm using aes128 engine - step 1 2866 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); 2867 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2868 sm_aes128_state = SM_AES128_ACTIVE; 2869 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); 2870 break; 2871 2872 case SM_PH2_CALC_STK: 2873 // already busy? 2874 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2875 // calculate STK 2876 if (IS_RESPONDER(connection->sm_role)){ 2877 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2878 } else { 2879 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2880 } 2881 connection->sm_engine_state = SM_PH2_W4_STK; 2882 sm_aes128_state = SM_AES128_ACTIVE; 2883 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); 2884 break; 2885 2886 case SM_PH3_Y_GET_ENC: 2887 // already busy? 2888 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2889 // PH3B2 - calculate Y from - enc 2890 2891 // dm helper (was sm_dm_r_prime) 2892 // r' = padding || r 2893 // r - 64 bit value 2894 memset(&sm_aes128_plaintext[0], 0, 8); 2895 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2896 2897 // Y = dm(DHK, Rand) 2898 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2899 sm_aes128_state = SM_AES128_ACTIVE; 2900 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); 2901 break; 2902 2903 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2904 uint8_t buffer[17]; 2905 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2906 reverse_128(setup->sm_local_confirm, &buffer[1]); 2907 if (IS_RESPONDER(connection->sm_role)){ 2908 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2909 } else { 2910 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2911 } 2912 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2913 sm_timeout_reset(connection); 2914 return; 2915 } 2916 #ifdef ENABLE_LE_PERIPHERAL 2917 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2918 sm_key_t stk_flipped; 2919 reverse_128(setup->sm_ltk, stk_flipped); 2920 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2921 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2922 return; 2923 } 2924 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2925 sm_key_t ltk_flipped; 2926 reverse_128(setup->sm_ltk, ltk_flipped); 2927 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2928 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2929 return; 2930 } 2931 2932 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2933 // already busy? 2934 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2935 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2936 2937 sm_reset_setup(); 2938 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2939 2940 sm_reencryption_started(connection); 2941 2942 // dm helper (was sm_dm_r_prime) 2943 // r' = padding || r 2944 // r - 64 bit value 2945 memset(&sm_aes128_plaintext[0], 0, 8); 2946 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2947 2948 // Y = dm(DHK, Rand) 2949 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2950 sm_aes128_state = SM_AES128_ACTIVE; 2951 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); 2952 return; 2953 #endif 2954 #ifdef ENABLE_LE_CENTRAL 2955 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2956 sm_key_t stk_flipped; 2957 reverse_128(setup->sm_ltk, stk_flipped); 2958 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2959 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2960 return; 2961 } 2962 #endif 2963 2964 case SM_PH3_DISTRIBUTE_KEYS: 2965 if (setup->sm_key_distribution_send_set != 0){ 2966 sm_run_distribute_keys(connection); 2967 return; 2968 } 2969 2970 // keys are sent 2971 if (IS_RESPONDER(connection->sm_role)){ 2972 // slave -> receive master keys if any 2973 if (sm_key_distribution_all_received(connection)){ 2974 sm_key_distribution_handle_all_received(connection); 2975 connection->sm_engine_state = SM_RESPONDER_IDLE; 2976 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2977 sm_done_for_handle(connection->sm_handle); 2978 } else { 2979 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2980 } 2981 } else { 2982 sm_master_pairing_success(connection); 2983 } 2984 break; 2985 2986 default: 2987 break; 2988 } 2989 2990 // check again if active connection was released 2991 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2992 } 2993 } 2994 2995 // sm_aes128_state stays active 2996 static void sm_handle_encryption_result_enc_a(void *arg){ 2997 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2998 sm_aes128_state = SM_AES128_IDLE; 2999 3000 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3001 if (connection == NULL) return; 3002 3003 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3004 sm_aes128_state = SM_AES128_ACTIVE; 3005 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); 3006 } 3007 3008 static void sm_handle_encryption_result_enc_b(void *arg){ 3009 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3010 sm_aes128_state = SM_AES128_IDLE; 3011 3012 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3013 if (connection == NULL) return; 3014 3015 log_info_key("c1!", setup->sm_local_confirm); 3016 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3017 sm_trigger_run(); 3018 } 3019 3020 // sm_aes128_state stays active 3021 static void sm_handle_encryption_result_enc_c(void *arg){ 3022 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3023 sm_aes128_state = SM_AES128_IDLE; 3024 3025 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3026 if (connection == NULL) return; 3027 3028 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3029 sm_aes128_state = SM_AES128_ACTIVE; 3030 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); 3031 } 3032 3033 static void sm_handle_encryption_result_enc_d(void * arg){ 3034 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3035 sm_aes128_state = SM_AES128_IDLE; 3036 3037 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3038 if (connection == NULL) return; 3039 3040 log_info_key("c1!", sm_aes128_ciphertext); 3041 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3042 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 3043 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3044 sm_trigger_run(); 3045 return; 3046 } 3047 if (IS_RESPONDER(connection->sm_role)){ 3048 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3049 sm_trigger_run(); 3050 } else { 3051 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3052 sm_aes128_state = SM_AES128_ACTIVE; 3053 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); 3054 } 3055 } 3056 3057 static void sm_handle_encryption_result_enc_stk(void *arg){ 3058 sm_aes128_state = SM_AES128_IDLE; 3059 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3060 3061 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3062 if (connection == NULL) return; 3063 3064 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3065 log_info_key("stk", setup->sm_ltk); 3066 if (IS_RESPONDER(connection->sm_role)){ 3067 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3068 } else { 3069 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3070 } 3071 sm_trigger_run(); 3072 } 3073 3074 // sm_aes128_state stays active 3075 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3076 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3077 sm_aes128_state = SM_AES128_IDLE; 3078 3079 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3080 if (connection == NULL) return; 3081 3082 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3083 log_info_hex16("y", setup->sm_local_y); 3084 // PH3B3 - calculate EDIV 3085 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3086 log_info_hex16("ediv", setup->sm_local_ediv); 3087 // PH3B4 - calculate LTK - enc 3088 // LTK = d1(ER, DIV, 0)) 3089 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3090 sm_aes128_state = SM_AES128_ACTIVE; 3091 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); 3092 } 3093 3094 #ifdef ENABLE_LE_PERIPHERAL 3095 // sm_aes128_state stays active 3096 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3097 sm_aes128_state = SM_AES128_IDLE; 3098 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3099 3100 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3101 if (connection == NULL) return; 3102 3103 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3104 log_info_hex16("y", setup->sm_local_y); 3105 3106 // PH3B3 - calculate DIV 3107 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3108 log_info_hex16("ediv", setup->sm_local_ediv); 3109 // PH3B4 - calculate LTK - enc 3110 // LTK = d1(ER, DIV, 0)) 3111 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3112 sm_aes128_state = SM_AES128_ACTIVE; 3113 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); 3114 } 3115 #endif 3116 3117 // sm_aes128_state stays active 3118 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3119 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3120 sm_aes128_state = SM_AES128_IDLE; 3121 3122 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3123 if (connection == NULL) return; 3124 3125 log_info_key("ltk", setup->sm_ltk); 3126 // calc CSRK next 3127 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3128 sm_aes128_state = SM_AES128_ACTIVE; 3129 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); 3130 } 3131 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3132 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3133 // requirements to derive link key from LE: 3134 // - use secure connections 3135 if (setup->sm_use_secure_connections == 0) return false; 3136 // - bonding needs to be enabled: 3137 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; 3138 if (!bonding_enabled) return false; 3139 // - need identity address 3140 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3141 if (!have_identity_address_info) return false; 3142 // - 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) 3143 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3144 // If SC is authenticated, we consider it safe to overwrite a stored key. 3145 // 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. 3146 uint8_t link_key[16]; 3147 link_key_type_t link_key_type; 3148 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3149 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3150 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3151 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3152 return false; 3153 } 3154 // get started (all of the above are true) 3155 return true; 3156 #else 3157 UNUSED(sm_connection); 3158 return false; 3159 #endif 3160 } 3161 3162 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3163 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3164 sm_aes128_state = SM_AES128_IDLE; 3165 3166 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3167 if (connection == NULL) return; 3168 3169 sm_aes128_state = SM_AES128_IDLE; 3170 log_info_key("csrk", setup->sm_local_csrk); 3171 if (setup->sm_key_distribution_send_set){ 3172 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3173 } else { 3174 // no keys to send, just continue 3175 if (IS_RESPONDER(connection->sm_role)){ 3176 // slave -> receive master keys 3177 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3178 } else { 3179 if (sm_ctkd_from_le(connection)){ 3180 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; 3181 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3182 } else { 3183 sm_master_pairing_success(connection); 3184 } 3185 } 3186 } 3187 sm_trigger_run(); 3188 } 3189 3190 #ifdef ENABLE_LE_PERIPHERAL 3191 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3192 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3193 sm_aes128_state = SM_AES128_IDLE; 3194 3195 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3196 if (connection == NULL) return; 3197 3198 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3199 log_info_key("ltk", setup->sm_ltk); 3200 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3201 sm_trigger_run(); 3202 } 3203 #endif 3204 3205 static void sm_handle_encryption_result_address_resolution(void *arg){ 3206 UNUSED(arg); 3207 sm_aes128_state = SM_AES128_IDLE; 3208 3209 sm_address_resolution_ah_calculation_active = 0; 3210 // compare calulated address against connecting device 3211 uint8_t * hash = &sm_aes128_ciphertext[13]; 3212 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3213 log_info("LE Device Lookup: matched resolvable private address"); 3214 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3215 sm_trigger_run(); 3216 return; 3217 } 3218 // no match, try next 3219 sm_address_resolution_test++; 3220 sm_trigger_run(); 3221 } 3222 3223 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3224 UNUSED(arg); 3225 sm_aes128_state = SM_AES128_IDLE; 3226 3227 log_info_key("irk", sm_persistent_irk); 3228 dkg_state = DKG_CALC_DHK; 3229 sm_trigger_run(); 3230 } 3231 3232 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3233 UNUSED(arg); 3234 sm_aes128_state = SM_AES128_IDLE; 3235 3236 log_info_key("dhk", sm_persistent_dhk); 3237 dkg_state = DKG_READY; 3238 sm_trigger_run(); 3239 } 3240 3241 static void sm_handle_encryption_result_rau(void *arg){ 3242 UNUSED(arg); 3243 sm_aes128_state = SM_AES128_IDLE; 3244 3245 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3246 rau_state = RAU_SET_ADDRESS; 3247 sm_trigger_run(); 3248 } 3249 3250 static void sm_handle_random_result_rau(void * arg){ 3251 UNUSED(arg); 3252 // non-resolvable vs. resolvable 3253 switch (gap_random_adress_type){ 3254 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3255 // resolvable: use random as prand and calc address hash 3256 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3257 sm_random_address[0u] &= 0x3fu; 3258 sm_random_address[0u] |= 0x40u; 3259 rau_state = RAU_GET_ENC; 3260 break; 3261 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3262 default: 3263 // "The two most significant bits of the address shall be equal to ‘0’"" 3264 sm_random_address[0u] &= 0x3fu; 3265 rau_state = RAU_SET_ADDRESS; 3266 break; 3267 } 3268 sm_trigger_run(); 3269 } 3270 3271 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3272 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3273 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3274 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3275 if (connection == NULL) return; 3276 3277 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3278 sm_trigger_run(); 3279 } 3280 3281 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3282 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3283 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3284 if (connection == NULL) return; 3285 3286 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3287 sm_trigger_run(); 3288 } 3289 #endif 3290 3291 static void sm_handle_random_result_ph2_random(void * arg){ 3292 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3293 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3294 if (connection == NULL) return; 3295 3296 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3297 sm_trigger_run(); 3298 } 3299 3300 static void sm_handle_random_result_ph2_tk(void * arg){ 3301 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3302 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3303 if (connection == NULL) return; 3304 3305 sm_reset_tk(); 3306 uint32_t tk; 3307 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3308 // map random to 0-999999 without speding much cycles on a modulus operation 3309 tk = little_endian_read_32(sm_random_data,0); 3310 tk = tk & 0xfffff; // 1048575 3311 if (tk >= 999999u){ 3312 tk = tk - 999999u; 3313 } 3314 } else { 3315 // override with pre-defined passkey 3316 tk = sm_fixed_passkey_in_display_role; 3317 } 3318 big_endian_store_32(setup->sm_tk, 12, tk); 3319 if (IS_RESPONDER(connection->sm_role)){ 3320 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3321 } else { 3322 if (setup->sm_use_secure_connections){ 3323 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3324 } else { 3325 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3326 sm_trigger_user_response(connection); 3327 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3328 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3329 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); 3330 } 3331 } 3332 } 3333 sm_trigger_run(); 3334 } 3335 3336 static void sm_handle_random_result_ph3_div(void * arg){ 3337 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3338 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3339 if (connection == NULL) return; 3340 3341 // use 16 bit from random value as div 3342 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3343 log_info_hex16("div", setup->sm_local_div); 3344 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3345 sm_trigger_run(); 3346 } 3347 3348 static void sm_handle_random_result_ph3_random(void * arg){ 3349 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3350 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3351 if (connection == NULL) return; 3352 3353 reverse_64(sm_random_data, setup->sm_local_rand); 3354 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3355 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3356 // no db for authenticated flag hack: store flag in bit 4 of LSB 3357 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3358 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3359 } 3360 static void sm_validate_er_ir(void){ 3361 // warn about default ER/IR 3362 bool warning = false; 3363 if (sm_ir_is_default()){ 3364 warning = true; 3365 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3366 } 3367 if (sm_er_is_default()){ 3368 warning = true; 3369 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3370 } 3371 if (warning) { 3372 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3373 } 3374 } 3375 3376 static void sm_handle_random_result_ir(void *arg){ 3377 sm_persistent_keys_random_active = false; 3378 if (arg != NULL){ 3379 // key generated, store in tlv 3380 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3381 log_info("Generated IR key. Store in TLV status: %d", status); 3382 UNUSED(status); 3383 } 3384 log_info_key("IR", sm_persistent_ir); 3385 dkg_state = DKG_CALC_IRK; 3386 3387 if (test_use_fixed_local_irk){ 3388 log_info_key("IRK", sm_persistent_irk); 3389 dkg_state = DKG_CALC_DHK; 3390 } 3391 3392 sm_trigger_run(); 3393 } 3394 3395 static void sm_handle_random_result_er(void *arg){ 3396 sm_persistent_keys_random_active = false; 3397 if (arg != 0){ 3398 // key generated, store in tlv 3399 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3400 log_info("Generated ER key. Store in TLV status: %d", status); 3401 UNUSED(status); 3402 } 3403 log_info_key("ER", sm_persistent_er); 3404 3405 // try load ir 3406 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3407 if (key_size == 16){ 3408 // ok, let's continue 3409 log_info("IR from TLV"); 3410 sm_handle_random_result_ir( NULL ); 3411 } else { 3412 // invalid, generate new random one 3413 sm_persistent_keys_random_active = true; 3414 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3415 } 3416 } 3417 3418 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3419 3420 UNUSED(channel); // ok: there is no channel 3421 UNUSED(size); // ok: fixed format HCI events 3422 3423 sm_connection_t * sm_conn; 3424 hci_con_handle_t con_handle; 3425 uint8_t status; 3426 switch (packet_type) { 3427 3428 case HCI_EVENT_PACKET: 3429 switch (hci_event_packet_get_type(packet)) { 3430 3431 case BTSTACK_EVENT_STATE: 3432 // bt stack activated, get started 3433 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3434 log_info("HCI Working!"); 3435 3436 // setup IR/ER with TLV 3437 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3438 if (sm_tlv_impl != NULL){ 3439 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3440 if (key_size == 16){ 3441 // ok, let's continue 3442 log_info("ER from TLV"); 3443 sm_handle_random_result_er( NULL ); 3444 } else { 3445 // invalid, generate random one 3446 sm_persistent_keys_random_active = true; 3447 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3448 } 3449 } else { 3450 sm_validate_er_ir(); 3451 dkg_state = DKG_CALC_IRK; 3452 3453 if (test_use_fixed_local_irk){ 3454 log_info_key("IRK", sm_persistent_irk); 3455 dkg_state = DKG_CALC_DHK; 3456 } 3457 } 3458 3459 // restart random address updates after power cycle 3460 gap_random_address_set_mode(gap_random_adress_type); 3461 } 3462 break; 3463 3464 case HCI_EVENT_LE_META: 3465 switch (packet[2]) { 3466 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3467 3468 log_info("sm: connected"); 3469 3470 if (packet[3]) return; // connection failed 3471 3472 con_handle = little_endian_read_16(packet, 4); 3473 sm_conn = sm_get_connection_for_handle(con_handle); 3474 if (!sm_conn) break; 3475 3476 sm_conn->sm_handle = con_handle; 3477 sm_conn->sm_role = packet[6]; 3478 sm_conn->sm_peer_addr_type = packet[7]; 3479 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3480 3481 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3482 3483 // reset security properties 3484 sm_conn->sm_connection_encrypted = 0; 3485 sm_conn->sm_connection_authenticated = 0; 3486 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3487 sm_conn->sm_le_db_index = -1; 3488 sm_conn->sm_reencryption_active = false; 3489 3490 // prepare CSRK lookup (does not involve setup) 3491 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3492 3493 // just connected -> everything else happens in sm_run() 3494 if (IS_RESPONDER(sm_conn->sm_role)){ 3495 // peripheral 3496 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3497 break; 3498 } else { 3499 // master 3500 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3501 } 3502 break; 3503 3504 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3505 con_handle = little_endian_read_16(packet, 3); 3506 sm_conn = sm_get_connection_for_handle(con_handle); 3507 if (!sm_conn) break; 3508 3509 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3510 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3511 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3512 break; 3513 } 3514 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3515 // PH2 SEND LTK as we need to exchange keys in PH3 3516 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3517 break; 3518 } 3519 3520 // store rand and ediv 3521 reverse_64(&packet[5], sm_conn->sm_local_rand); 3522 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3523 3524 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3525 // potentially stored LTK is from the master 3526 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3527 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3528 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3529 break; 3530 } 3531 // additionally check if remote is in LE Device DB if requested 3532 switch(sm_conn->sm_irk_lookup_state){ 3533 case IRK_LOOKUP_FAILED: 3534 log_info("LTK Request: device not in device db"); 3535 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3536 break; 3537 case IRK_LOOKUP_SUCCEEDED: 3538 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3539 break; 3540 default: 3541 // wait for irk look doen 3542 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3543 break; 3544 } 3545 break; 3546 } 3547 3548 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3549 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3550 #else 3551 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3552 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3553 #endif 3554 break; 3555 3556 default: 3557 break; 3558 } 3559 break; 3560 3561 case HCI_EVENT_ENCRYPTION_CHANGE: 3562 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3563 sm_conn = sm_get_connection_for_handle(con_handle); 3564 if (!sm_conn) break; 3565 3566 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3567 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3568 sm_conn->sm_actual_encryption_key_size); 3569 log_info("event handler, state %u", sm_conn->sm_engine_state); 3570 3571 switch (sm_conn->sm_engine_state){ 3572 3573 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3574 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3575 if (sm_conn->sm_connection_encrypted) { 3576 status = ERROR_CODE_SUCCESS; 3577 if (sm_conn->sm_role){ 3578 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3579 } else { 3580 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3581 } 3582 } else { 3583 status = hci_event_encryption_change_get_status(packet); 3584 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3585 // also, gap_reconnect_security_setup_active will return true 3586 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3587 } 3588 3589 // emit re-encryption complete 3590 sm_reencryption_complete(sm_conn, status); 3591 3592 // notify client, if pairing was requested before 3593 if (sm_conn->sm_pairing_requested){ 3594 sm_conn->sm_pairing_requested = 0; 3595 sm_pairing_complete(sm_conn, status, 0); 3596 } 3597 3598 sm_done_for_handle(sm_conn->sm_handle); 3599 break; 3600 3601 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3602 if (!sm_conn->sm_connection_encrypted) break; 3603 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3604 if (IS_RESPONDER(sm_conn->sm_role)){ 3605 // slave 3606 if (setup->sm_use_secure_connections){ 3607 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3608 } else { 3609 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); 3610 } 3611 } else { 3612 // master 3613 if (sm_key_distribution_all_received(sm_conn)){ 3614 // skip receiving keys as there are none 3615 sm_key_distribution_handle_all_received(sm_conn); 3616 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); 3617 } else { 3618 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3619 } 3620 } 3621 break; 3622 default: 3623 break; 3624 } 3625 break; 3626 3627 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3628 con_handle = little_endian_read_16(packet, 3); 3629 sm_conn = sm_get_connection_for_handle(con_handle); 3630 if (!sm_conn) break; 3631 3632 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3633 log_info("event handler, state %u", sm_conn->sm_engine_state); 3634 // continue if part of initial pairing 3635 switch (sm_conn->sm_engine_state){ 3636 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3637 if (sm_conn->sm_role){ 3638 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3639 } else { 3640 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3641 } 3642 sm_done_for_handle(sm_conn->sm_handle); 3643 break; 3644 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3645 if (IS_RESPONDER(sm_conn->sm_role)){ 3646 // slave 3647 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); 3648 } else { 3649 // master 3650 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3651 } 3652 break; 3653 default: 3654 break; 3655 } 3656 break; 3657 3658 3659 case HCI_EVENT_DISCONNECTION_COMPLETE: 3660 con_handle = little_endian_read_16(packet, 3); 3661 sm_done_for_handle(con_handle); 3662 sm_conn = sm_get_connection_for_handle(con_handle); 3663 if (!sm_conn) break; 3664 3665 // pairing failed, if it was ongoing 3666 switch (sm_conn->sm_engine_state){ 3667 case SM_GENERAL_IDLE: 3668 case SM_INITIATOR_CONNECTED: 3669 case SM_RESPONDER_IDLE: 3670 break; 3671 default: 3672 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3673 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3674 break; 3675 } 3676 3677 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3678 sm_conn->sm_handle = 0; 3679 break; 3680 3681 case HCI_EVENT_COMMAND_COMPLETE: 3682 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3683 // set local addr for le device db 3684 bd_addr_t addr; 3685 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3686 le_device_db_set_local_bd_addr(addr); 3687 } 3688 break; 3689 default: 3690 break; 3691 } 3692 break; 3693 default: 3694 break; 3695 } 3696 3697 sm_run(); 3698 } 3699 3700 static inline int sm_calc_actual_encryption_key_size(int other){ 3701 if (other < sm_min_encryption_key_size) return 0; 3702 if (other < sm_max_encryption_key_size) return other; 3703 return sm_max_encryption_key_size; 3704 } 3705 3706 3707 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3708 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3709 switch (method){ 3710 case JUST_WORKS: 3711 case NUMERIC_COMPARISON: 3712 return 1; 3713 default: 3714 return 0; 3715 } 3716 } 3717 // responder 3718 3719 static int sm_passkey_used(stk_generation_method_t method){ 3720 switch (method){ 3721 case PK_RESP_INPUT: 3722 return 1; 3723 default: 3724 return 0; 3725 } 3726 } 3727 3728 static int sm_passkey_entry(stk_generation_method_t method){ 3729 switch (method){ 3730 case PK_RESP_INPUT: 3731 case PK_INIT_INPUT: 3732 case PK_BOTH_INPUT: 3733 return 1; 3734 default: 3735 return 0; 3736 } 3737 } 3738 3739 #endif 3740 3741 /** 3742 * @return ok 3743 */ 3744 static int sm_validate_stk_generation_method(void){ 3745 // check if STK generation method is acceptable by client 3746 switch (setup->sm_stk_generation_method){ 3747 case JUST_WORKS: 3748 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3749 case PK_RESP_INPUT: 3750 case PK_INIT_INPUT: 3751 case PK_BOTH_INPUT: 3752 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3753 case OOB: 3754 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3755 case NUMERIC_COMPARISON: 3756 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3757 default: 3758 return 0; 3759 } 3760 } 3761 3762 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3763 3764 // size of complete sm_pdu used to validate input 3765 static const uint8_t sm_pdu_size[] = { 3766 0, // 0x00 invalid opcode 3767 7, // 0x01 pairing request 3768 7, // 0x02 pairing response 3769 17, // 0x03 pairing confirm 3770 17, // 0x04 pairing random 3771 2, // 0x05 pairing failed 3772 17, // 0x06 encryption information 3773 11, // 0x07 master identification 3774 17, // 0x08 identification information 3775 8, // 0x09 identify address information 3776 17, // 0x0a signing information 3777 2, // 0x0b security request 3778 65, // 0x0c pairing public key 3779 17, // 0x0d pairing dhk check 3780 2, // 0x0e keypress notification 3781 }; 3782 3783 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3784 sm_run(); 3785 } 3786 3787 if (packet_type != SM_DATA_PACKET) return; 3788 if (size == 0u) return; 3789 3790 uint8_t sm_pdu_code = packet[0]; 3791 3792 // validate pdu size 3793 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3794 if (sm_pdu_size[sm_pdu_code] != size) return; 3795 3796 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3797 if (!sm_conn) return; 3798 3799 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3800 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 3801 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3802 sm_done_for_handle(con_handle); 3803 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3804 return; 3805 } 3806 3807 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3808 3809 int err; 3810 UNUSED(err); 3811 3812 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3813 uint8_t buffer[5]; 3814 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3815 buffer[1] = 3; 3816 little_endian_store_16(buffer, 2, con_handle); 3817 buffer[4] = packet[1]; 3818 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3819 return; 3820 } 3821 3822 #ifdef ENABLE_LE_CENTRAL 3823 int have_ltk; 3824 uint8_t ltk[16]; 3825 #endif 3826 3827 switch (sm_conn->sm_engine_state){ 3828 3829 // a sm timeout requires a new physical connection 3830 case SM_GENERAL_TIMEOUT: 3831 return; 3832 3833 #ifdef ENABLE_LE_CENTRAL 3834 3835 // Initiator 3836 case SM_INITIATOR_CONNECTED: 3837 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3838 sm_pdu_received_in_wrong_state(sm_conn); 3839 break; 3840 } 3841 3842 // IRK complete? 3843 switch (sm_conn->sm_irk_lookup_state){ 3844 case IRK_LOOKUP_FAILED: 3845 // start pairing 3846 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3847 break; 3848 case IRK_LOOKUP_SUCCEEDED: 3849 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3850 have_ltk = !sm_is_null_key(ltk); 3851 log_info("central: security request - have_ltk %u", have_ltk); 3852 if (have_ltk){ 3853 // start re-encrypt 3854 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 3855 } else { 3856 // start pairing 3857 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3858 } 3859 break; 3860 default: 3861 // otherwise, store security request 3862 sm_conn->sm_security_request_received = 1; 3863 break; 3864 } 3865 break; 3866 3867 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3868 // Core 5, Vol 3, Part H, 2.4.6: 3869 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3870 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3871 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3872 log_info("Ignoring Security Request"); 3873 break; 3874 } 3875 3876 // all other pdus are incorrect 3877 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3878 sm_pdu_received_in_wrong_state(sm_conn); 3879 break; 3880 } 3881 3882 // store pairing request 3883 (void)memcpy(&setup->sm_s_pres, packet, 3884 sizeof(sm_pairing_packet_t)); 3885 err = sm_stk_generation_init(sm_conn); 3886 3887 #ifdef ENABLE_TESTING_SUPPORT 3888 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3889 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3890 err = test_pairing_failure; 3891 } 3892 #endif 3893 3894 if (err != 0){ 3895 setup->sm_pairing_failed_reason = err; 3896 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3897 break; 3898 } 3899 3900 // generate random number first, if we need to show passkey 3901 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3902 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); 3903 break; 3904 } 3905 3906 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3907 if (setup->sm_use_secure_connections){ 3908 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3909 if (setup->sm_stk_generation_method == JUST_WORKS){ 3910 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3911 sm_trigger_user_response(sm_conn); 3912 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3913 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3914 } 3915 } else { 3916 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3917 } 3918 break; 3919 } 3920 #endif 3921 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3922 sm_trigger_user_response(sm_conn); 3923 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3924 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3925 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); 3926 } 3927 break; 3928 3929 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3930 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3931 sm_pdu_received_in_wrong_state(sm_conn); 3932 break; 3933 } 3934 3935 // store s_confirm 3936 reverse_128(&packet[1], setup->sm_peer_confirm); 3937 3938 // abort if s_confirm matches m_confirm 3939 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 3940 sm_pdu_received_in_wrong_state(sm_conn); 3941 break; 3942 } 3943 3944 #ifdef ENABLE_TESTING_SUPPORT 3945 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3946 log_info("testing_support: reset confirm value"); 3947 memset(setup->sm_peer_confirm, 0, 16); 3948 } 3949 #endif 3950 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3951 break; 3952 3953 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3954 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3955 sm_pdu_received_in_wrong_state(sm_conn); 3956 break;; 3957 } 3958 3959 // received random value 3960 reverse_128(&packet[1], setup->sm_peer_random); 3961 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3962 break; 3963 #endif 3964 3965 #ifdef ENABLE_LE_PERIPHERAL 3966 // Responder 3967 case SM_RESPONDER_IDLE: 3968 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3969 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3970 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3971 sm_pdu_received_in_wrong_state(sm_conn); 3972 break;; 3973 } 3974 3975 // store pairing request 3976 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3977 3978 // check if IRK completed 3979 switch (sm_conn->sm_irk_lookup_state){ 3980 case IRK_LOOKUP_SUCCEEDED: 3981 case IRK_LOOKUP_FAILED: 3982 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3983 break; 3984 default: 3985 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 3986 break; 3987 } 3988 break; 3989 #endif 3990 3991 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3992 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3993 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3994 sm_pdu_received_in_wrong_state(sm_conn); 3995 break; 3996 } 3997 3998 // store public key for DH Key calculation 3999 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4000 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4001 4002 // validate public key 4003 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4004 if (err != 0){ 4005 log_error("sm: peer public key invalid %x", err); 4006 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4007 break; 4008 } 4009 4010 // start calculating dhkey 4011 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); 4012 4013 4014 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4015 if (IS_RESPONDER(sm_conn->sm_role)){ 4016 // responder 4017 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4018 } else { 4019 // initiator 4020 // stk generation method 4021 // passkey entry: notify app to show passkey or to request passkey 4022 switch (setup->sm_stk_generation_method){ 4023 case JUST_WORKS: 4024 case NUMERIC_COMPARISON: 4025 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4026 break; 4027 case PK_RESP_INPUT: 4028 sm_sc_start_calculating_local_confirm(sm_conn); 4029 break; 4030 case PK_INIT_INPUT: 4031 case PK_BOTH_INPUT: 4032 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4033 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4034 break; 4035 } 4036 sm_sc_start_calculating_local_confirm(sm_conn); 4037 break; 4038 case OOB: 4039 // generate Nx 4040 log_info("Generate Na"); 4041 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); 4042 break; 4043 default: 4044 btstack_assert(false); 4045 break; 4046 } 4047 } 4048 break; 4049 4050 case SM_SC_W4_CONFIRMATION: 4051 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4052 sm_pdu_received_in_wrong_state(sm_conn); 4053 break; 4054 } 4055 // received confirm value 4056 reverse_128(&packet[1], setup->sm_peer_confirm); 4057 4058 #ifdef ENABLE_TESTING_SUPPORT 4059 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4060 log_info("testing_support: reset confirm value"); 4061 memset(setup->sm_peer_confirm, 0, 16); 4062 } 4063 #endif 4064 if (IS_RESPONDER(sm_conn->sm_role)){ 4065 // responder 4066 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4067 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4068 // still waiting for passkey 4069 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4070 break; 4071 } 4072 } 4073 sm_sc_start_calculating_local_confirm(sm_conn); 4074 } else { 4075 // initiator 4076 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4077 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); 4078 } else { 4079 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4080 } 4081 } 4082 break; 4083 4084 case SM_SC_W4_PAIRING_RANDOM: 4085 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4086 sm_pdu_received_in_wrong_state(sm_conn); 4087 break; 4088 } 4089 4090 // received random value 4091 reverse_128(&packet[1], setup->sm_peer_nonce); 4092 4093 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4094 // only check for JUST WORK/NC in initiator role OR passkey entry 4095 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4096 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4097 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4098 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4099 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4100 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4101 break; 4102 } 4103 4104 // OOB 4105 if (setup->sm_stk_generation_method == OOB){ 4106 4107 // setup local random, set to zero if remote did not receive our data 4108 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4109 if (IS_RESPONDER(sm_conn->sm_role)){ 4110 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4111 log_info("Reset rb as A does not have OOB data"); 4112 memset(setup->sm_rb, 0, 16); 4113 } else { 4114 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4115 log_info("Use stored rb"); 4116 log_info_hexdump(setup->sm_rb, 16); 4117 } 4118 } else { 4119 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4120 log_info("Reset ra as B does not have OOB data"); 4121 memset(setup->sm_ra, 0, 16); 4122 } else { 4123 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4124 log_info("Use stored ra"); 4125 log_info_hexdump(setup->sm_ra, 16); 4126 } 4127 } 4128 4129 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4130 if (setup->sm_have_oob_data){ 4131 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4132 break; 4133 } 4134 } 4135 4136 // TODO: we only get here for Responder role with JW/NC 4137 sm_sc_state_after_receiving_random(sm_conn); 4138 break; 4139 4140 case SM_SC_W2_CALCULATE_G2: 4141 case SM_SC_W4_CALCULATE_G2: 4142 case SM_SC_W4_CALCULATE_DHKEY: 4143 case SM_SC_W2_CALCULATE_F5_SALT: 4144 case SM_SC_W4_CALCULATE_F5_SALT: 4145 case SM_SC_W2_CALCULATE_F5_MACKEY: 4146 case SM_SC_W4_CALCULATE_F5_MACKEY: 4147 case SM_SC_W2_CALCULATE_F5_LTK: 4148 case SM_SC_W4_CALCULATE_F5_LTK: 4149 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4150 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4151 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4152 case SM_SC_W4_USER_RESPONSE: 4153 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4154 sm_pdu_received_in_wrong_state(sm_conn); 4155 break; 4156 } 4157 // store DHKey Check 4158 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4159 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4160 4161 // have we been only waiting for dhkey check command? 4162 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4163 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4164 } 4165 break; 4166 #endif 4167 4168 #ifdef ENABLE_LE_PERIPHERAL 4169 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4170 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4171 sm_pdu_received_in_wrong_state(sm_conn); 4172 break; 4173 } 4174 4175 // received confirm value 4176 reverse_128(&packet[1], setup->sm_peer_confirm); 4177 4178 #ifdef ENABLE_TESTING_SUPPORT 4179 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4180 log_info("testing_support: reset confirm value"); 4181 memset(setup->sm_peer_confirm, 0, 16); 4182 } 4183 #endif 4184 // notify client to hide shown passkey 4185 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4186 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4187 } 4188 4189 // handle user cancel pairing? 4190 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4191 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4192 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4193 break; 4194 } 4195 4196 // wait for user action? 4197 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4198 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4199 break; 4200 } 4201 4202 // calculate and send local_confirm 4203 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); 4204 break; 4205 4206 case SM_RESPONDER_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 case SM_PH3_RECEIVE_KEYS: 4219 switch(sm_pdu_code){ 4220 case SM_CODE_ENCRYPTION_INFORMATION: 4221 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4222 reverse_128(&packet[1], setup->sm_peer_ltk); 4223 break; 4224 4225 case SM_CODE_MASTER_IDENTIFICATION: 4226 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4227 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4228 reverse_64(&packet[3], setup->sm_peer_rand); 4229 break; 4230 4231 case SM_CODE_IDENTITY_INFORMATION: 4232 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4233 reverse_128(&packet[1], setup->sm_peer_irk); 4234 break; 4235 4236 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4237 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4238 setup->sm_peer_addr_type = packet[1]; 4239 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4240 break; 4241 4242 case SM_CODE_SIGNING_INFORMATION: 4243 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4244 reverse_128(&packet[1], setup->sm_peer_csrk); 4245 break; 4246 default: 4247 // Unexpected PDU 4248 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4249 break; 4250 } 4251 // done with key distribution? 4252 if (sm_key_distribution_all_received(sm_conn)){ 4253 4254 sm_key_distribution_handle_all_received(sm_conn); 4255 4256 if (IS_RESPONDER(sm_conn->sm_role)){ 4257 if (sm_ctkd_from_le(sm_conn)){ 4258 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; 4259 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4260 } else { 4261 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4262 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 4263 sm_done_for_handle(sm_conn->sm_handle); 4264 } 4265 } else { 4266 if (setup->sm_use_secure_connections){ 4267 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4268 } else { 4269 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); 4270 } 4271 } 4272 } 4273 break; 4274 default: 4275 // Unexpected PDU 4276 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4277 break; 4278 } 4279 4280 // try to send next pdu 4281 sm_trigger_run(); 4282 } 4283 4284 // Security Manager Client API 4285 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4286 sm_get_oob_data = get_oob_data_callback; 4287 } 4288 4289 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)){ 4290 sm_get_sc_oob_data = get_sc_oob_data_callback; 4291 } 4292 4293 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4294 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4295 } 4296 4297 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4298 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4299 } 4300 4301 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4302 sm_min_encryption_key_size = min_size; 4303 sm_max_encryption_key_size = max_size; 4304 } 4305 4306 void sm_set_authentication_requirements(uint8_t auth_req){ 4307 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4308 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4309 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4310 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4311 } 4312 #endif 4313 sm_auth_req = auth_req; 4314 } 4315 4316 void sm_set_io_capabilities(io_capability_t io_capability){ 4317 sm_io_capabilities = io_capability; 4318 } 4319 4320 #ifdef ENABLE_LE_PERIPHERAL 4321 void sm_set_request_security(int enable){ 4322 sm_slave_request_security = enable; 4323 } 4324 #endif 4325 4326 void sm_set_er(sm_key_t er){ 4327 (void)memcpy(sm_persistent_er, er, 16); 4328 } 4329 4330 void sm_set_ir(sm_key_t ir){ 4331 (void)memcpy(sm_persistent_ir, ir, 16); 4332 } 4333 4334 // Testing support only 4335 void sm_test_set_irk(sm_key_t irk){ 4336 (void)memcpy(sm_persistent_irk, irk, 16); 4337 dkg_state = DKG_CALC_DHK; 4338 test_use_fixed_local_irk = true; 4339 } 4340 4341 void sm_test_use_fixed_local_csrk(void){ 4342 test_use_fixed_local_csrk = true; 4343 } 4344 4345 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4346 static void sm_ec_generated(void * arg){ 4347 UNUSED(arg); 4348 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4349 // trigger pairing if pending for ec key 4350 sm_trigger_run(); 4351 } 4352 static void sm_ec_generate_new_key(void){ 4353 log_info("sm: generate new ec key"); 4354 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4355 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4356 } 4357 #endif 4358 4359 #ifdef ENABLE_TESTING_SUPPORT 4360 void sm_test_set_pairing_failure(int reason){ 4361 test_pairing_failure = reason; 4362 } 4363 #endif 4364 4365 void sm_init(void){ 4366 4367 if (sm_initialized) return; 4368 4369 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4370 sm_er_ir_set_default(); 4371 4372 // defaults 4373 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4374 | SM_STK_GENERATION_METHOD_OOB 4375 | SM_STK_GENERATION_METHOD_PASSKEY 4376 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4377 4378 sm_max_encryption_key_size = 16; 4379 sm_min_encryption_key_size = 7; 4380 4381 sm_fixed_passkey_in_display_role = 0xffffffff; 4382 sm_reconstruct_ltk_without_le_device_db_entry = true; 4383 4384 #ifdef USE_CMAC_ENGINE 4385 sm_cmac_active = 0; 4386 #endif 4387 dkg_state = DKG_W4_WORKING; 4388 rau_state = RAU_IDLE; 4389 sm_aes128_state = SM_AES128_IDLE; 4390 sm_address_resolution_test = -1; // no private address to resolve yet 4391 sm_address_resolution_ah_calculation_active = 0; 4392 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4393 sm_address_resolution_general_queue = NULL; 4394 4395 gap_random_adress_update_period = 15 * 60 * 1000L; 4396 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4397 4398 test_use_fixed_local_csrk = false; 4399 4400 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4401 4402 // register for HCI Events from HCI 4403 hci_event_callback_registration.callback = &sm_event_packet_handler; 4404 hci_add_event_handler(&hci_event_callback_registration); 4405 4406 // 4407 btstack_crypto_init(); 4408 4409 // init le_device_db 4410 le_device_db_init(); 4411 4412 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4413 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4414 4415 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4416 sm_ec_generate_new_key(); 4417 #endif 4418 4419 sm_initialized = true; 4420 } 4421 4422 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4423 sm_fixed_passkey_in_display_role = passkey; 4424 } 4425 4426 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4427 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4428 } 4429 4430 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4431 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4432 if (!hci_con) return NULL; 4433 return &hci_con->sm_connection; 4434 } 4435 4436 // @deprecated: map onto sm_request_pairing 4437 void sm_send_security_request(hci_con_handle_t con_handle){ 4438 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4439 if (!sm_conn) return; 4440 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4441 sm_request_pairing(con_handle); 4442 } 4443 4444 // request pairing 4445 void sm_request_pairing(hci_con_handle_t con_handle){ 4446 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4447 if (!sm_conn) return; // wrong connection 4448 4449 bool have_ltk; 4450 uint8_t ltk[16]; 4451 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4452 if (IS_RESPONDER(sm_conn->sm_role)){ 4453 switch (sm_conn->sm_engine_state){ 4454 case SM_GENERAL_IDLE: 4455 case SM_RESPONDER_IDLE: 4456 switch (sm_conn->sm_irk_lookup_state){ 4457 case IRK_LOOKUP_SUCCEEDED: 4458 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4459 have_ltk = !sm_is_null_key(ltk); 4460 log_info("have ltk %u", have_ltk); 4461 if (have_ltk){ 4462 sm_conn->sm_pairing_requested = 1; 4463 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4464 sm_reencryption_started(sm_conn); 4465 break; 4466 } 4467 /* fall through */ 4468 4469 case IRK_LOOKUP_FAILED: 4470 sm_conn->sm_pairing_requested = 1; 4471 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4472 sm_pairing_started(sm_conn); 4473 break; 4474 default: 4475 log_info("irk lookup pending"); 4476 sm_conn->sm_pairing_requested = 1; 4477 break; 4478 } 4479 break; 4480 default: 4481 break; 4482 } 4483 } else { 4484 // used as a trigger to start central/master/initiator security procedures 4485 switch (sm_conn->sm_engine_state){ 4486 case SM_INITIATOR_CONNECTED: 4487 switch (sm_conn->sm_irk_lookup_state){ 4488 case IRK_LOOKUP_SUCCEEDED: 4489 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4490 have_ltk = !sm_is_null_key(ltk); 4491 log_info("have ltk %u", have_ltk); 4492 if (have_ltk){ 4493 sm_conn->sm_pairing_requested = 1; 4494 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4495 break; 4496 } 4497 /* fall through */ 4498 4499 case IRK_LOOKUP_FAILED: 4500 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4501 break; 4502 default: 4503 log_info("irk lookup pending"); 4504 sm_conn->sm_pairing_requested = 1; 4505 break; 4506 } 4507 break; 4508 case SM_GENERAL_REENCRYPTION_FAILED: 4509 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4510 break; 4511 case SM_GENERAL_IDLE: 4512 sm_conn->sm_pairing_requested = 1; 4513 break; 4514 default: 4515 break; 4516 } 4517 } 4518 sm_trigger_run(); 4519 } 4520 4521 // called by client app on authorization request 4522 void sm_authorization_decline(hci_con_handle_t con_handle){ 4523 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4524 if (!sm_conn) return; // wrong connection 4525 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4526 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4527 } 4528 4529 void sm_authorization_grant(hci_con_handle_t con_handle){ 4530 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4531 if (!sm_conn) return; // wrong connection 4532 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4533 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4534 } 4535 4536 // GAP Bonding API 4537 4538 void sm_bonding_decline(hci_con_handle_t con_handle){ 4539 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4540 if (!sm_conn) return; // wrong connection 4541 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4542 log_info("decline, state %u", sm_conn->sm_engine_state); 4543 switch(sm_conn->sm_engine_state){ 4544 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4545 case SM_SC_W4_USER_RESPONSE: 4546 case SM_SC_W4_CONFIRMATION: 4547 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4548 #endif 4549 case SM_PH1_W4_USER_RESPONSE: 4550 switch (setup->sm_stk_generation_method){ 4551 case PK_RESP_INPUT: 4552 case PK_INIT_INPUT: 4553 case PK_BOTH_INPUT: 4554 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4555 break; 4556 case NUMERIC_COMPARISON: 4557 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4558 break; 4559 case JUST_WORKS: 4560 case OOB: 4561 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4562 break; 4563 default: 4564 btstack_assert(false); 4565 break; 4566 } 4567 break; 4568 default: 4569 break; 4570 } 4571 sm_trigger_run(); 4572 } 4573 4574 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4575 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4576 if (!sm_conn) return; // wrong connection 4577 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4578 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4579 if (setup->sm_use_secure_connections){ 4580 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4581 } else { 4582 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); 4583 } 4584 } 4585 4586 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4587 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4588 sm_sc_prepare_dhkey_check(sm_conn); 4589 } 4590 #endif 4591 4592 sm_trigger_run(); 4593 } 4594 4595 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4596 // for now, it's the same 4597 sm_just_works_confirm(con_handle); 4598 } 4599 4600 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4601 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4602 if (!sm_conn) return; // wrong connection 4603 sm_reset_tk(); 4604 big_endian_store_32(setup->sm_tk, 12, passkey); 4605 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4606 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4607 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); 4608 } 4609 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4610 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4611 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4612 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4613 sm_sc_start_calculating_local_confirm(sm_conn); 4614 } 4615 #endif 4616 sm_trigger_run(); 4617 } 4618 4619 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4620 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4621 if (!sm_conn) return; // wrong connection 4622 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4623 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4624 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4625 switch (action){ 4626 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4627 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4628 flags |= (1u << action); 4629 break; 4630 case SM_KEYPRESS_PASSKEY_CLEARED: 4631 // clear counter, keypress & erased flags + set passkey cleared 4632 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4633 break; 4634 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4635 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4636 // erase actions queued 4637 num_actions--; 4638 if (num_actions == 0u){ 4639 // clear counter, keypress & erased flags 4640 flags &= 0x19u; 4641 } 4642 break; 4643 } 4644 num_actions++; 4645 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4646 break; 4647 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4648 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4649 // enter actions queued 4650 num_actions--; 4651 if (num_actions == 0u){ 4652 // clear counter, keypress & erased flags 4653 flags &= 0x19u; 4654 } 4655 break; 4656 } 4657 num_actions++; 4658 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4659 break; 4660 default: 4661 break; 4662 } 4663 setup->sm_keypress_notification = (num_actions << 5) | flags; 4664 sm_trigger_run(); 4665 } 4666 4667 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4668 static void sm_handle_random_result_oob(void * arg){ 4669 UNUSED(arg); 4670 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4671 sm_trigger_run(); 4672 } 4673 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4674 4675 static btstack_crypto_random_t sm_crypto_random_oob_request; 4676 4677 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4678 sm_sc_oob_callback = callback; 4679 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4680 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4681 return 0; 4682 } 4683 #endif 4684 4685 /** 4686 * @brief Get Identity Resolving state 4687 * @param con_handle 4688 * @return irk_lookup_state_t 4689 */ 4690 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4691 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4692 if (!sm_conn) return IRK_LOOKUP_IDLE; 4693 return sm_conn->sm_irk_lookup_state; 4694 } 4695 4696 /** 4697 * @brief Identify device in LE Device DB 4698 * @param handle 4699 * @returns index from le_device_db or -1 if not found/identified 4700 */ 4701 int sm_le_device_index(hci_con_handle_t con_handle ){ 4702 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4703 if (!sm_conn) return -1; 4704 return sm_conn->sm_le_db_index; 4705 } 4706 4707 static int gap_random_address_type_requires_updates(void){ 4708 switch (gap_random_adress_type){ 4709 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4710 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4711 return 0; 4712 default: 4713 return 1; 4714 } 4715 } 4716 4717 static uint8_t own_address_type(void){ 4718 switch (gap_random_adress_type){ 4719 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4720 return BD_ADDR_TYPE_LE_PUBLIC; 4721 default: 4722 return BD_ADDR_TYPE_LE_RANDOM; 4723 } 4724 } 4725 4726 // GAP LE API 4727 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4728 gap_random_address_update_stop(); 4729 gap_random_adress_type = random_address_type; 4730 hci_le_set_own_address_type(own_address_type()); 4731 if (!gap_random_address_type_requires_updates()) return; 4732 gap_random_address_update_start(); 4733 gap_random_address_trigger(); 4734 } 4735 4736 gap_random_address_type_t gap_random_address_get_mode(void){ 4737 return gap_random_adress_type; 4738 } 4739 4740 void gap_random_address_set_update_period(int period_ms){ 4741 gap_random_adress_update_period = period_ms; 4742 if (!gap_random_address_type_requires_updates()) return; 4743 gap_random_address_update_stop(); 4744 gap_random_address_update_start(); 4745 } 4746 4747 void gap_random_address_set(const bd_addr_t addr){ 4748 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4749 (void)memcpy(sm_random_address, addr, 6); 4750 rau_state = RAU_SET_ADDRESS; 4751 sm_trigger_run(); 4752 } 4753 4754 #ifdef ENABLE_LE_PERIPHERAL 4755 /* 4756 * @brief Set Advertisement Paramters 4757 * @param adv_int_min 4758 * @param adv_int_max 4759 * @param adv_type 4760 * @param direct_address_type 4761 * @param direct_address 4762 * @param channel_map 4763 * @param filter_policy 4764 * 4765 * @note own_address_type is used from gap_random_address_set_mode 4766 */ 4767 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4768 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4769 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4770 direct_address_typ, direct_address, channel_map, filter_policy); 4771 } 4772 #endif 4773 4774 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4775 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4776 // wrong connection 4777 if (!sm_conn) return 0; 4778 // already encrypted 4779 if (sm_conn->sm_connection_encrypted) return 0; 4780 // irk status? 4781 switch(sm_conn->sm_irk_lookup_state){ 4782 case IRK_LOOKUP_FAILED: 4783 // done, cannot setup encryption 4784 return 0; 4785 case IRK_LOOKUP_SUCCEEDED: 4786 break; 4787 default: 4788 // IR Lookup pending 4789 return 1; 4790 } 4791 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 4792 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 4793 if (sm_conn->sm_role){ 4794 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 4795 } else { 4796 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4797 } 4798 } 4799 4800 void sm_set_secure_connections_only_mode(bool enable){ 4801 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4802 sm_sc_only_mode = enable; 4803 #else 4804 // SC Only mode not possible without support for SC 4805 btstack_assert(enable == false); 4806 #endif 4807 } 4808 4809 const uint8_t * gap_get_persistent_irk(void){ 4810 return sm_persistent_irk; 4811 } 4812 4813 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 4814 uint16_t i; 4815 for (i=0; i < le_device_db_max_count(); i++){ 4816 bd_addr_t entry_address; 4817 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 4818 le_device_db_info(i, &entry_address_type, entry_address, NULL); 4819 // skip unused entries 4820 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 4821 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 4822 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 4823 hci_remove_le_device_db_entry_from_resolving_list(i); 4824 #endif 4825 le_device_db_remove(i); 4826 break; 4827 } 4828 } 4829 } 4830