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