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) == HCI_ROLE_SLAVE) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && ((role) == HCI_ROLE_SLAVE)) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || ((role) == HCI_ROLE_SLAVE)) 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 bool 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 #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY 210 static bool sm_sc_debug_keys_enabled; 211 #endif 212 #endif 213 214 215 static bool sm_persistent_keys_random_active; 216 static const btstack_tlv_t * sm_tlv_impl; 217 static void * sm_tlv_context; 218 219 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 220 static sm_key_t sm_persistent_er; 221 static sm_key_t sm_persistent_ir; 222 223 // derived from sm_persistent_ir 224 static sm_key_t sm_persistent_dhk; 225 static sm_key_t sm_persistent_irk; 226 static derived_key_generation_t dkg_state; 227 228 // derived from sm_persistent_er 229 // .. 230 231 // random address update 232 static random_address_update_t rau_state; 233 static bd_addr_t sm_random_address; 234 235 #ifdef USE_CMAC_ENGINE 236 // CMAC Calculation: General 237 static btstack_crypto_aes128_cmac_t sm_cmac_request; 238 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 239 static uint8_t sm_cmac_active; 240 static uint8_t sm_cmac_hash[16]; 241 #endif 242 243 // CMAC for ATT Signed Writes 244 #ifdef ENABLE_LE_SIGNED_WRITE 245 static uint16_t sm_cmac_signed_write_message_len; 246 static uint8_t sm_cmac_signed_write_header[3]; 247 static const uint8_t * sm_cmac_signed_write_message; 248 static uint8_t sm_cmac_signed_write_sign_counter[4]; 249 #endif 250 251 // CMAC for Secure Connection functions 252 #ifdef ENABLE_LE_SECURE_CONNECTIONS 253 static sm_connection_t * sm_cmac_connection; 254 static uint8_t sm_cmac_sc_buffer[80]; 255 #endif 256 257 // resolvable private address lookup / CSRK calculation 258 static int sm_address_resolution_test; 259 static uint8_t sm_address_resolution_addr_type; 260 static bd_addr_t sm_address_resolution_address; 261 static void * sm_address_resolution_context; 262 static address_resolution_mode_t sm_address_resolution_mode; 263 static btstack_linked_list_t sm_address_resolution_general_queue; 264 265 // aes128 crypto engine. 266 static sm_aes128_state_t sm_aes128_state; 267 268 // crypto 269 static btstack_crypto_random_t sm_crypto_random_request; 270 static btstack_crypto_aes128_t sm_crypto_aes128_request; 271 #ifdef ENABLE_LE_SECURE_CONNECTIONS 272 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 273 #endif 274 275 // temp storage for random data 276 static uint8_t sm_random_data[8]; 277 static uint8_t sm_aes128_key[16]; 278 static uint8_t sm_aes128_plaintext[16]; 279 static uint8_t sm_aes128_ciphertext[16]; 280 281 // to receive events 282 static btstack_packet_callback_registration_t hci_event_callback_registration; 283 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 284 static btstack_packet_callback_registration_t l2cap_event_callback_registration; 285 #endif 286 287 /* to dispatch sm event */ 288 static btstack_linked_list_t sm_event_handlers; 289 290 /* to schedule calls to sm_run */ 291 static btstack_timer_source_t sm_run_timer; 292 293 // LE Secure Connections 294 #ifdef ENABLE_LE_SECURE_CONNECTIONS 295 static ec_key_generation_state_t ec_key_generation_state; 296 static uint8_t ec_q[64]; 297 #endif 298 299 // 300 // Volume 3, Part H, Chapter 24 301 // "Security shall be initiated by the Security Manager in the device in the master role. 302 // The device in the slave role shall be the responding device." 303 // -> master := initiator, slave := responder 304 // 305 306 // data needed for security setup 307 typedef struct sm_setup_context { 308 309 btstack_timer_source_t sm_timeout; 310 311 // user response, (Phase 1 and/or 2) 312 uint8_t sm_user_response; 313 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 314 315 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 316 uint8_t sm_key_distribution_send_set; 317 uint8_t sm_key_distribution_sent_set; 318 uint8_t sm_key_distribution_expected_set; 319 uint8_t sm_key_distribution_received_set; 320 321 // Phase 2 (Pairing over SMP) 322 stk_generation_method_t sm_stk_generation_method; 323 sm_key_t sm_tk; 324 uint8_t sm_have_oob_data; 325 bool sm_use_secure_connections; 326 327 sm_key_t sm_c1_t3_value; // c1 calculation 328 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 329 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 330 sm_key_t sm_local_random; 331 sm_key_t sm_local_confirm; 332 sm_key_t sm_peer_random; 333 sm_key_t sm_peer_confirm; 334 uint8_t sm_m_addr_type; // address and type can be removed 335 uint8_t sm_s_addr_type; // '' 336 bd_addr_t sm_m_address; // '' 337 bd_addr_t sm_s_address; // '' 338 sm_key_t sm_ltk; 339 340 uint8_t sm_state_vars; 341 #ifdef ENABLE_LE_SECURE_CONNECTIONS 342 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 343 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 344 sm_key_t sm_local_nonce; // might be combined with sm_local_random 345 uint8_t sm_dhkey[32]; 346 sm_key_t sm_peer_dhkey_check; 347 sm_key_t sm_local_dhkey_check; 348 sm_key_t sm_ra; 349 sm_key_t sm_rb; 350 sm_key_t sm_t; // used for f5 and h6 351 sm_key_t sm_mackey; 352 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 353 #endif 354 355 // Phase 3 356 357 // key distribution, we generate 358 uint16_t sm_local_y; 359 uint16_t sm_local_div; 360 uint16_t sm_local_ediv; 361 uint8_t sm_local_rand[8]; 362 sm_key_t sm_local_ltk; 363 sm_key_t sm_local_csrk; 364 sm_key_t sm_local_irk; 365 // sm_local_address/addr_type not needed 366 367 // key distribution, received from peer 368 uint16_t sm_peer_y; 369 uint16_t sm_peer_div; 370 uint16_t sm_peer_ediv; 371 uint8_t sm_peer_rand[8]; 372 sm_key_t sm_peer_ltk; 373 sm_key_t sm_peer_irk; 374 sm_key_t sm_peer_csrk; 375 uint8_t sm_peer_addr_type; 376 bd_addr_t sm_peer_address; 377 #ifdef ENABLE_LE_SIGNED_WRITE 378 int sm_le_device_index; 379 #endif 380 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 381 link_key_t sm_link_key; 382 link_key_type_t sm_link_key_type; 383 #endif 384 } sm_setup_context_t; 385 386 // 387 static sm_setup_context_t the_setup; 388 static sm_setup_context_t * setup = &the_setup; 389 390 // active connection - the one for which the_setup is used for 391 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 392 393 // @return 1 if oob data is available 394 // stores oob data in provided 16 byte buffer if not null 395 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 396 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); 397 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 398 399 static void sm_run(void); 400 static void sm_state_reset(void); 401 static void sm_done_for_handle(hci_con_handle_t con_handle); 402 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 403 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk); 404 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 405 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 406 #endif 407 static inline int sm_calc_actual_encryption_key_size(int other); 408 static int sm_validate_stk_generation_method(void); 409 static void sm_handle_encryption_result_address_resolution(void *arg); 410 static void sm_handle_encryption_result_dkg_dhk(void *arg); 411 static void sm_handle_encryption_result_dkg_irk(void *arg); 412 static void sm_handle_encryption_result_enc_a(void *arg); 413 static void sm_handle_encryption_result_enc_b(void *arg); 414 static void sm_handle_encryption_result_enc_c(void *arg); 415 static void sm_handle_encryption_result_enc_csrk(void *arg); 416 static void sm_handle_encryption_result_enc_d(void * arg); 417 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 418 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 419 #ifdef ENABLE_LE_PERIPHERAL 420 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 421 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 422 #endif 423 static void sm_handle_encryption_result_enc_stk(void *arg); 424 static void sm_handle_encryption_result_rau(void *arg); 425 static void sm_handle_random_result_ph2_tk(void * arg); 426 static void sm_handle_random_result_rau(void * arg); 427 #ifdef ENABLE_LE_SECURE_CONNECTIONS 428 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)); 429 static void sm_ec_generate_new_key(void); 430 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 431 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 432 static bool sm_passkey_entry(stk_generation_method_t method); 433 #endif 434 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 435 436 static void log_info_hex16(const char * name, uint16_t value){ 437 UNUSED(name); 438 UNUSED(value); 439 log_info("%-6s 0x%04x", name, value); 440 } 441 442 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 443 // return packet[0]; 444 // } 445 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 446 return packet[1]; 447 } 448 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 449 return packet[2]; 450 } 451 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 452 return packet[3]; 453 } 454 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 455 return packet[4]; 456 } 457 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 458 return packet[5]; 459 } 460 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 461 return packet[6]; 462 } 463 464 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 465 packet[0] = code; 466 } 467 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 468 packet[1] = io_capability; 469 } 470 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 471 packet[2] = oob_data_flag; 472 } 473 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 474 packet[3] = auth_req; 475 } 476 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 477 packet[4] = max_encryption_key_size; 478 } 479 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 480 packet[5] = initiator_key_distribution; 481 } 482 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 483 packet[6] = responder_key_distribution; 484 } 485 486 static bool sm_is_null_random(uint8_t random[8]){ 487 return btstack_is_null(random, 8); 488 } 489 490 static bool sm_is_null_key(uint8_t * key){ 491 return btstack_is_null(key, 16); 492 } 493 494 #ifdef ENABLE_LE_SECURE_CONNECTIONS 495 static bool sm_is_ff(const uint8_t * buffer, uint16_t size){ 496 uint16_t i; 497 for (i=0; i < size ; i++){ 498 if (buffer[i] != 0xff) { 499 return false; 500 } 501 } 502 return true; 503 } 504 #endif 505 506 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 507 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 508 UNUSED(ts); 509 sm_run(); 510 } 511 static void sm_trigger_run(void){ 512 if (!sm_initialized) return; 513 (void)btstack_run_loop_remove_timer(&sm_run_timer); 514 btstack_run_loop_set_timer(&sm_run_timer, 0); 515 btstack_run_loop_add_timer(&sm_run_timer); 516 } 517 518 // Key utils 519 static void sm_reset_tk(void){ 520 int i; 521 for (i=0;i<16;i++){ 522 setup->sm_tk[i] = 0; 523 } 524 } 525 526 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 527 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 528 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 529 int i; 530 for (i = max_encryption_size ; i < 16 ; i++){ 531 key[15-i] = 0; 532 } 533 } 534 535 // ER / IR checks 536 static void sm_er_ir_set_default(void){ 537 int i; 538 for (i=0;i<16;i++){ 539 sm_persistent_er[i] = 0x30 + i; 540 sm_persistent_ir[i] = 0x90 + i; 541 } 542 } 543 544 static bool sm_er_is_default(void){ 545 int i; 546 for (i=0;i<16;i++){ 547 if (sm_persistent_er[i] != (0x30+i)) return true; 548 } 549 return false; 550 } 551 552 static bool sm_ir_is_default(void){ 553 int i; 554 for (i=0;i<16;i++){ 555 if (sm_persistent_ir[i] != (0x90+i)) return true; 556 } 557 return false; 558 } 559 560 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 561 UNUSED(channel); 562 563 // log event 564 hci_dump_btstack_event(packet, size); 565 // dispatch to all event handlers 566 btstack_linked_list_iterator_t it; 567 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 568 while (btstack_linked_list_iterator_has_next(&it)){ 569 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 570 entry->callback(packet_type, 0, packet, size); 571 } 572 } 573 574 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){ 575 event[0] = type; 576 event[1] = event_size - 2; 577 little_endian_store_16(event, 2, con_handle); 578 event[4] = addr_type; 579 reverse_bd_addr(address, &event[5]); 580 } 581 582 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 583 uint8_t event[11]; 584 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 585 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 586 } 587 588 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){ 589 // fetch addr and addr type from db, only called for valid entries 590 bd_addr_t identity_address; 591 int identity_address_type; 592 le_device_db_info(index, &identity_address_type, identity_address, NULL); 593 594 uint8_t event[20]; 595 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 596 event[11] = identity_address_type; 597 reverse_bd_addr(identity_address, &event[12]); 598 little_endian_store_16(event, 18, index); 599 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 600 } 601 602 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){ 603 uint8_t event[12]; 604 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 605 event[11] = status; 606 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 607 } 608 609 610 static void sm_reencryption_started(sm_connection_t * sm_conn){ 611 612 if (sm_conn->sm_reencryption_active) return; 613 614 sm_conn->sm_reencryption_active = true; 615 616 int identity_addr_type; 617 bd_addr_t identity_addr; 618 if (sm_conn->sm_le_db_index >= 0){ 619 // fetch addr and addr type from db, only called for valid entries 620 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 621 } else { 622 // for legacy pairing with LTK re-construction, use current peer addr 623 identity_addr_type = sm_conn->sm_peer_addr_type; 624 // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy 625 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 626 } 627 628 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 629 } 630 631 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 632 633 if (!sm_conn->sm_reencryption_active) return; 634 635 sm_conn->sm_reencryption_active = false; 636 637 int identity_addr_type; 638 bd_addr_t identity_addr; 639 if (sm_conn->sm_le_db_index >= 0){ 640 // fetch addr and addr type from db, only called for valid entries 641 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 642 } else { 643 // for legacy pairing with LTK re-construction, use current peer addr 644 identity_addr_type = sm_conn->sm_peer_addr_type; 645 // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy 646 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 647 } 648 649 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 650 } 651 652 static void sm_pairing_started(sm_connection_t * sm_conn){ 653 654 if (sm_conn->sm_pairing_active) return; 655 656 sm_conn->sm_pairing_active = true; 657 658 uint8_t event[11]; 659 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 660 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 661 } 662 663 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 664 665 if (!sm_conn->sm_pairing_active) return; 666 667 sm_conn->sm_pairing_active = false; 668 669 uint8_t event[13]; 670 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 671 event[11] = status; 672 event[12] = reason; 673 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 674 } 675 676 // SMP Timeout implementation 677 678 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 679 // the Security Manager Timer shall be reset and started. 680 // 681 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 682 // 683 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 684 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 685 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 686 // established. 687 688 static void sm_timeout_handler(btstack_timer_source_t * timer){ 689 log_info("SM timeout"); 690 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 691 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 692 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 693 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 694 sm_done_for_handle(sm_conn->sm_handle); 695 696 // trigger handling of next ready connection 697 sm_run(); 698 } 699 static void sm_timeout_start(sm_connection_t * sm_conn){ 700 btstack_run_loop_remove_timer(&setup->sm_timeout); 701 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 702 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 703 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 704 btstack_run_loop_add_timer(&setup->sm_timeout); 705 } 706 static void sm_timeout_stop(void){ 707 btstack_run_loop_remove_timer(&setup->sm_timeout); 708 } 709 static void sm_timeout_reset(sm_connection_t * sm_conn){ 710 sm_timeout_stop(); 711 sm_timeout_start(sm_conn); 712 } 713 714 // end of sm timeout 715 716 // GAP Random Address updates 717 static gap_random_address_type_t gap_random_adress_type; 718 static btstack_timer_source_t gap_random_address_update_timer; 719 static uint32_t gap_random_adress_update_period; 720 721 static void gap_random_address_trigger(void){ 722 log_info("gap_random_address_trigger, state %u", rau_state); 723 if (rau_state != RAU_IDLE) return; 724 rau_state = RAU_GET_RANDOM; 725 sm_trigger_run(); 726 } 727 728 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 729 UNUSED(timer); 730 731 log_info("GAP Random Address Update due"); 732 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 733 btstack_run_loop_add_timer(&gap_random_address_update_timer); 734 gap_random_address_trigger(); 735 } 736 737 static void gap_random_address_update_start(void){ 738 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 739 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 740 btstack_run_loop_add_timer(&gap_random_address_update_timer); 741 } 742 743 static void gap_random_address_update_stop(void){ 744 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 745 } 746 747 // ah(k,r) helper 748 // r = padding || r 749 // r - 24 bit value 750 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 751 // r'= padding || r 752 memset(r_prime, 0, 16); 753 (void)memcpy(&r_prime[13], r, 3); 754 } 755 756 // d1 helper 757 // d' = padding || r || d 758 // d,r - 16 bit values 759 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 760 // d'= padding || r || d 761 memset(d1_prime, 0, 16); 762 big_endian_store_16(d1_prime, 12, r); 763 big_endian_store_16(d1_prime, 14, d); 764 } 765 766 // calculate arguments for first AES128 operation in C1 function 767 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){ 768 769 // p1 = pres || preq || rat’ || iat’ 770 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 771 // cant octet of pres becomes the most significant octet of p1. 772 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 773 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 774 // p1 is 0x05000800000302070710000001010001." 775 776 sm_key_t p1; 777 reverse_56(pres, &p1[0]); 778 reverse_56(preq, &p1[7]); 779 p1[14] = rat; 780 p1[15] = iat; 781 log_info_key("p1", p1); 782 log_info_key("r", r); 783 784 // t1 = r xor p1 785 int i; 786 for (i=0;i<16;i++){ 787 t1[i] = r[i] ^ p1[i]; 788 } 789 log_info_key("t1", t1); 790 } 791 792 // calculate arguments for second AES128 operation in C1 function 793 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 794 // p2 = padding || ia || ra 795 // "The least significant octet of ra becomes the least significant octet of p2 and 796 // the most significant octet of padding becomes the most significant octet of p2. 797 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 798 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 799 800 sm_key_t p2; 801 // cppcheck-suppress uninitvar ; p2 is reported as uninitialized 802 memset(p2, 0, 16); 803 (void)memcpy(&p2[4], ia, 6); 804 (void)memcpy(&p2[10], ra, 6); 805 log_info_key("p2", p2); 806 807 // c1 = e(k, t2_xor_p2) 808 int i; 809 for (i=0;i<16;i++){ 810 t3[i] = t2[i] ^ p2[i]; 811 } 812 log_info_key("t3", t3); 813 } 814 815 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 816 log_info_key("r1", r1); 817 log_info_key("r2", r2); 818 (void)memcpy(&r_prime[8], &r2[8], 8); 819 (void)memcpy(&r_prime[0], &r1[8], 8); 820 } 821 822 823 // decide on stk generation based on 824 // - pairing request 825 // - io capabilities 826 // - OOB data availability 827 static void sm_setup_tk(void){ 828 829 // horizontal: initiator capabilities 830 // vertial: responder capabilities 831 static const stk_generation_method_t stk_generation_method [5] [5] = { 832 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 833 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 834 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 835 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 836 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 837 }; 838 839 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 840 #ifdef ENABLE_LE_SECURE_CONNECTIONS 841 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 842 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 843 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 844 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 845 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 846 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 847 }; 848 #endif 849 850 // default: just works 851 setup->sm_stk_generation_method = JUST_WORKS; 852 853 #ifdef ENABLE_LE_SECURE_CONNECTIONS 854 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 855 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 856 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 857 #else 858 setup->sm_use_secure_connections = false; 859 #endif 860 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 861 862 863 // decide if OOB will be used based on SC vs. Legacy and oob flags 864 bool use_oob; 865 if (setup->sm_use_secure_connections){ 866 // In LE Secure Connections pairing, the out of band method is used if at least 867 // one device has the peer device's out of band authentication data available. 868 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; 869 } else { 870 // In LE legacy pairing, the out of band method is used if both the devices have 871 // the other device's out of band authentication data available. 872 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; 873 } 874 if (use_oob){ 875 log_info("SM: have OOB data"); 876 log_info_key("OOB", setup->sm_tk); 877 setup->sm_stk_generation_method = OOB; 878 return; 879 } 880 881 // If both devices have not set the MITM option in the Authentication Requirements 882 // Flags, then the IO capabilities shall be ignored and the Just Works association 883 // model shall be used. 884 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 885 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 886 log_info("SM: MITM not required by both -> JUST WORKS"); 887 return; 888 } 889 890 // Reset TK as it has been setup in sm_init_setup 891 sm_reset_tk(); 892 893 // Also use just works if unknown io capabilites 894 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)){ 895 return; 896 } 897 898 // Otherwise the IO capabilities of the devices shall be used to determine the 899 // pairing method as defined in Table 2.4. 900 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 901 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 902 903 #ifdef ENABLE_LE_SECURE_CONNECTIONS 904 // table not define by default 905 if (setup->sm_use_secure_connections){ 906 generation_method = stk_generation_method_with_secure_connection; 907 } 908 #endif 909 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)]; 910 911 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 912 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); 913 } 914 915 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 916 int flags = 0; 917 if ((key_set & SM_KEYDIST_ENC_KEY) != 0u){ 918 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 919 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 920 } 921 if ((key_set & SM_KEYDIST_ID_KEY) != 0u){ 922 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 923 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 924 } 925 if ((key_set & SM_KEYDIST_SIGN) != 0u){ 926 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 927 } 928 return flags; 929 } 930 931 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 932 setup->sm_key_distribution_received_set = 0; 933 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 934 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 935 setup->sm_key_distribution_sent_set = 0; 936 #ifdef ENABLE_LE_SIGNED_WRITE 937 setup->sm_le_device_index = -1; 938 #endif 939 } 940 941 // CSRK Key Lookup 942 943 944 static bool sm_address_resolution_idle(void){ 945 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 946 } 947 948 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){ 949 (void)memcpy(sm_address_resolution_address, addr, 6); 950 sm_address_resolution_addr_type = addr_type; 951 sm_address_resolution_test = 0; 952 sm_address_resolution_mode = mode; 953 sm_address_resolution_context = context; 954 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 955 } 956 957 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 958 // check if already in list 959 btstack_linked_list_iterator_t it; 960 sm_lookup_entry_t * entry; 961 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 962 while(btstack_linked_list_iterator_has_next(&it)){ 963 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 964 if (entry->address_type != address_type) continue; 965 if (memcmp(entry->address, address, 6) != 0) continue; 966 // already in list 967 return BTSTACK_BUSY; 968 } 969 entry = btstack_memory_sm_lookup_entry_get(); 970 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 971 entry->address_type = (bd_addr_type_t) address_type; 972 (void)memcpy(entry->address, address, 6); 973 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 974 sm_trigger_run(); 975 return 0; 976 } 977 978 // CMAC calculation using AES Engineq 979 #ifdef USE_CMAC_ENGINE 980 981 static void sm_cmac_done_trampoline(void * arg){ 982 UNUSED(arg); 983 sm_cmac_active = 0; 984 (*sm_cmac_done_callback)(sm_cmac_hash); 985 sm_trigger_run(); 986 } 987 988 int sm_cmac_ready(void){ 989 return sm_cmac_active == 0u; 990 } 991 #endif 992 993 #ifdef ENABLE_LE_SECURE_CONNECTIONS 994 // generic cmac calculation 995 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)){ 996 sm_cmac_active = 1; 997 sm_cmac_done_callback = done_callback; 998 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 999 } 1000 #endif 1001 1002 // cmac for ATT Message signing 1003 #ifdef ENABLE_LE_SIGNED_WRITE 1004 1005 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)){ 1006 sm_cmac_active = 1; 1007 sm_cmac_done_callback = done_callback; 1008 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 1009 } 1010 1011 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1012 if (offset >= sm_cmac_signed_write_message_len) { 1013 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1014 return 0; 1015 } 1016 1017 offset = sm_cmac_signed_write_message_len - 1 - offset; 1018 1019 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1020 if (offset < 3){ 1021 return sm_cmac_signed_write_header[offset]; 1022 } 1023 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1024 if (offset < actual_message_len_incl_header){ 1025 return sm_cmac_signed_write_message[offset - 3]; 1026 } 1027 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1028 } 1029 1030 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)){ 1031 // ATT Message Signing 1032 sm_cmac_signed_write_header[0] = opcode; 1033 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1034 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1035 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1036 sm_cmac_signed_write_message = message; 1037 sm_cmac_signed_write_message_len = total_message_len; 1038 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1039 } 1040 #endif 1041 1042 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1043 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1044 uint8_t event[12]; 1045 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1046 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1047 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1048 } 1049 1050 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn, uint8_t event_type){ 1051 uint8_t event[16]; 1052 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1053 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, 1054 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1055 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1056 little_endian_store_32(event, 12, passkey); 1057 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1058 } 1059 1060 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1061 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1062 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1063 sm_conn->sm_pairing_active = true; 1064 switch (setup->sm_stk_generation_method){ 1065 case PK_RESP_INPUT: 1066 if (IS_RESPONDER(sm_conn->sm_role)){ 1067 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1068 } else { 1069 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); 1070 } 1071 break; 1072 case PK_INIT_INPUT: 1073 if (IS_RESPONDER(sm_conn->sm_role)){ 1074 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); 1075 } else { 1076 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1077 } 1078 break; 1079 case PK_BOTH_INPUT: 1080 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1081 break; 1082 case NUMERIC_COMPARISON: 1083 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1084 break; 1085 case JUST_WORKS: 1086 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1087 break; 1088 case OOB: 1089 // client already provided OOB data, let's skip notification. 1090 break; 1091 default: 1092 btstack_assert(false); 1093 break; 1094 } 1095 } 1096 1097 static bool sm_key_distribution_all_received(void) { 1098 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, setup->sm_key_distribution_expected_set); 1099 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1100 } 1101 1102 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1103 if (sm_active_connection_handle == con_handle){ 1104 sm_timeout_stop(); 1105 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1106 log_info("sm: connection 0x%x released setup context", con_handle); 1107 1108 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1109 // generate new ec key after each pairing (that used it) 1110 if (setup->sm_use_secure_connections){ 1111 sm_ec_generate_new_key(); 1112 } 1113 #endif 1114 } 1115 } 1116 1117 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1118 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1119 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1120 sm_done_for_handle(connection->sm_handle); 1121 } 1122 1123 static int sm_key_distribution_flags_for_auth_req(void){ 1124 1125 int flags = SM_KEYDIST_ID_KEY; 1126 if ((sm_auth_req & SM_AUTHREQ_BONDING) != 0u){ 1127 // encryption and signing information only if bonding requested 1128 flags |= SM_KEYDIST_ENC_KEY; 1129 #ifdef ENABLE_LE_SIGNED_WRITE 1130 flags |= SM_KEYDIST_SIGN; 1131 #endif 1132 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1133 // LinkKey for CTKD requires SC and BR/EDR Support 1134 if (hci_classic_supported() && ((sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION) != 0)){ 1135 flags |= SM_KEYDIST_LINK_KEY; 1136 } 1137 #endif 1138 } 1139 return flags; 1140 } 1141 1142 static void sm_reset_setup(void){ 1143 // fill in sm setup 1144 setup->sm_state_vars = 0; 1145 setup->sm_keypress_notification = 0; 1146 setup->sm_have_oob_data = 0; 1147 sm_reset_tk(); 1148 } 1149 1150 static void sm_init_setup(sm_connection_t * sm_conn){ 1151 // fill in sm setup 1152 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1153 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1154 1155 // query client for Legacy Pairing OOB data 1156 if (sm_get_oob_data != NULL) { 1157 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1158 } 1159 1160 // if available and SC supported, also ask for SC OOB Data 1161 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1162 memset(setup->sm_ra, 0, 16); 1163 memset(setup->sm_rb, 0, 16); 1164 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1165 if (sm_get_sc_oob_data != NULL){ 1166 if (IS_RESPONDER(sm_conn->sm_role)){ 1167 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1168 sm_conn->sm_peer_addr_type, 1169 sm_conn->sm_peer_address, 1170 setup->sm_peer_confirm, 1171 setup->sm_ra); 1172 } else { 1173 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1174 sm_conn->sm_peer_addr_type, 1175 sm_conn->sm_peer_address, 1176 setup->sm_peer_confirm, 1177 setup->sm_rb); 1178 } 1179 } else { 1180 setup->sm_have_oob_data = 0; 1181 } 1182 } 1183 #endif 1184 1185 sm_pairing_packet_t * local_packet; 1186 if (IS_RESPONDER(sm_conn->sm_role)){ 1187 // slave 1188 local_packet = &setup->sm_s_pres; 1189 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1190 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1191 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1192 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1193 } else { 1194 // master 1195 local_packet = &setup->sm_m_preq; 1196 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1197 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1198 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1199 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1200 1201 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1202 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1203 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1204 } 1205 1206 log_info("our address %s type %u", bd_addr_to_str(sm_conn->sm_own_address), sm_conn->sm_own_addr_type); 1207 log_info("peer address %s type %u", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); 1208 1209 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1210 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1211 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1212 // enable SC for SC only mode 1213 if (sm_sc_only_mode){ 1214 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1215 max_encryption_key_size = 16; 1216 } 1217 #endif 1218 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1219 // set CT2 if SC + Bonding + CTKD 1220 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1221 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1222 auth_req |= SM_AUTHREQ_CT2; 1223 } 1224 #endif 1225 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1226 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1227 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1228 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1229 } 1230 1231 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1232 1233 sm_pairing_packet_t * remote_packet; 1234 uint8_t keys_to_send; 1235 uint8_t keys_to_receive; 1236 if (IS_RESPONDER(sm_conn->sm_role)){ 1237 // slave / responder 1238 remote_packet = &setup->sm_m_preq; 1239 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1240 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1241 } else { 1242 // master / initiator 1243 remote_packet = &setup->sm_s_pres; 1244 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1245 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1246 } 1247 1248 // check key size 1249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1250 // SC Only mandates 128 bit key size 1251 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1252 return SM_REASON_ENCRYPTION_KEY_SIZE; 1253 } 1254 #endif 1255 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1256 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1257 1258 // decide on STK generation method / SC 1259 sm_setup_tk(); 1260 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1261 1262 // check if STK generation method is acceptable by client 1263 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1264 1265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1266 // Check LE SC Only mode 1267 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1268 log_info("SC Only mode active but SC not possible"); 1269 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1270 } 1271 1272 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1273 if (setup->sm_use_secure_connections){ 1274 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1275 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1276 } 1277 #endif 1278 1279 // identical to responder 1280 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1281 1282 // JUST WORKS doens't provide authentication 1283 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1284 1285 return 0; 1286 } 1287 1288 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1289 1290 // cache and reset context 1291 int matched_device_id = sm_address_resolution_test; 1292 address_resolution_mode_t mode = sm_address_resolution_mode; 1293 void * context = sm_address_resolution_context; 1294 1295 // reset context 1296 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1297 sm_address_resolution_context = NULL; 1298 sm_address_resolution_test = -1; 1299 1300 hci_con_handle_t con_handle = HCI_CON_HANDLE_INVALID; 1301 sm_connection_t * sm_connection; 1302 sm_key_t ltk; 1303 bool have_ltk; 1304 int authenticated; 1305 #ifdef ENABLE_LE_CENTRAL 1306 bool trigger_pairing; 1307 #endif 1308 1309 switch (mode){ 1310 case ADDRESS_RESOLUTION_GENERAL: 1311 break; 1312 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1313 sm_connection = (sm_connection_t *) context; 1314 con_handle = sm_connection->sm_handle; 1315 1316 // have ltk -> start encryption / send security request 1317 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1318 // "When a bond has been created between two devices, any reconnection should result in the local device 1319 // enabling or requesting encryption with the remote device before initiating any service request." 1320 1321 switch (event){ 1322 case ADDRESS_RESOLUTION_SUCCEEDED: 1323 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1324 sm_connection->sm_le_db_index = matched_device_id; 1325 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1326 1327 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); 1328 have_ltk = !sm_is_null_key(ltk); 1329 1330 if (IS_RESPONDER(sm_connection->sm_role)) { 1331 #ifdef ENABLE_LE_PERIPHERAL 1332 // IRK required before, continue 1333 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1334 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1335 break; 1336 } 1337 // Pairing request before, continue 1338 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1339 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1340 break; 1341 } 1342 bool trigger_security_request = sm_connection->sm_pairing_requested || sm_slave_request_security; 1343 sm_connection->sm_pairing_requested = false; 1344 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1345 // trigger security request for Proactive Authentication if LTK available 1346 trigger_security_request = trigger_security_request || have_ltk; 1347 #endif 1348 1349 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1350 (int) sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1351 1352 if (trigger_security_request){ 1353 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1354 if (have_ltk){ 1355 sm_reencryption_started(sm_connection); 1356 } else { 1357 sm_pairing_started(sm_connection); 1358 } 1359 sm_trigger_run(); 1360 } 1361 #endif 1362 } else { 1363 1364 #ifdef ENABLE_LE_CENTRAL 1365 // check if pairing already requested and reset requests 1366 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1367 bool auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; 1368 1369 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1370 (int) sm_connection->sm_pairing_requested, (int) sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1371 sm_connection->sm_security_request_received = false; 1372 sm_connection->sm_pairing_requested = false; 1373 bool trigger_reencryption = false; 1374 1375 if (have_ltk){ 1376 if (trigger_pairing){ 1377 // if pairing is requested, re-encryption is sufficient, if ltk is already authenticated or we don't require authentication 1378 trigger_reencryption = (authenticated != 0) || (auth_required == false); 1379 } else { 1380 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1381 trigger_reencryption = true; 1382 #else 1383 log_info("central: defer enabling encryption for bonded device"); 1384 #endif 1385 } 1386 } 1387 1388 if (trigger_reencryption){ 1389 log_info("central: enable encryption for bonded device"); 1390 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1391 break; 1392 } 1393 1394 // pairing_request -> send pairing request 1395 if (trigger_pairing){ 1396 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1397 break; 1398 } 1399 #endif 1400 } 1401 break; 1402 case ADDRESS_RESOLUTION_FAILED: 1403 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1404 if (IS_RESPONDER(sm_connection->sm_role)) { 1405 #ifdef ENABLE_LE_PERIPHERAL 1406 // LTK request received before, IRK required -> negative LTK reply 1407 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1408 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1409 } 1410 // Pairing request before, continue 1411 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1412 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1413 break; 1414 } 1415 // send security request if requested 1416 bool trigger_security_request = sm_connection->sm_pairing_requested || sm_slave_request_security; 1417 sm_connection->sm_pairing_requested = false; 1418 if (trigger_security_request){ 1419 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1420 sm_pairing_started(sm_connection); 1421 } 1422 break; 1423 #endif 1424 } 1425 #ifdef ENABLE_LE_CENTRAL 1426 if ((sm_connection->sm_pairing_requested == false) && (sm_connection->sm_security_request_received == false)) break; 1427 sm_connection->sm_security_request_received = false; 1428 sm_connection->sm_pairing_requested = false; 1429 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1430 #endif 1431 break; 1432 1433 default: 1434 btstack_assert(false); 1435 break; 1436 } 1437 break; 1438 default: 1439 break; 1440 } 1441 1442 switch (event){ 1443 case ADDRESS_RESOLUTION_SUCCEEDED: 1444 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1445 break; 1446 case ADDRESS_RESOLUTION_FAILED: 1447 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1448 break; 1449 default: 1450 btstack_assert(false); 1451 break; 1452 } 1453 } 1454 1455 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1456 int le_db_index = -1; 1457 1458 // lookup device based on IRK 1459 if ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 1460 int i; 1461 for (i=0; i < le_device_db_max_count(); i++){ 1462 sm_key_t irk; 1463 bd_addr_t address; 1464 int address_type = BD_ADDR_TYPE_UNKNOWN; 1465 le_device_db_info(i, &address_type, address, irk); 1466 // skip unused entries 1467 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1468 // compare Identity Address 1469 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1470 // compare Identity Resolving Key 1471 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1472 1473 log_info("sm: device found for IRK, updating"); 1474 le_db_index = i; 1475 break; 1476 } 1477 } else { 1478 // assert IRK is set to zero 1479 memset(setup->sm_peer_irk, 0, 16); 1480 } 1481 1482 // if not found, lookup via public address if possible 1483 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1484 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1485 int i; 1486 for (i=0; i < le_device_db_max_count(); i++){ 1487 bd_addr_t address; 1488 int address_type = BD_ADDR_TYPE_UNKNOWN; 1489 le_device_db_info(i, &address_type, address, NULL); 1490 // skip unused entries 1491 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1492 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1493 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1494 log_info("sm: device found for public address, updating"); 1495 le_db_index = i; 1496 break; 1497 } 1498 } 1499 } 1500 1501 // if not found, add to db 1502 bool new_to_le_device_db = false; 1503 if (le_db_index < 0) { 1504 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1505 new_to_le_device_db = true; 1506 } 1507 1508 if (le_db_index >= 0){ 1509 1510 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1511 if (!new_to_le_device_db){ 1512 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1513 } 1514 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1515 #else 1516 UNUSED(new_to_le_device_db); 1517 #endif 1518 1519 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1520 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1521 sm_conn->sm_le_db_index = le_db_index; 1522 1523 #ifdef ENABLE_LE_SIGNED_WRITE 1524 // store local CSRK 1525 setup->sm_le_device_index = le_db_index; 1526 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1527 log_info("sm: store local CSRK"); 1528 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1529 le_device_db_local_counter_set(le_db_index, 0); 1530 } 1531 1532 // store remote CSRK 1533 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1534 log_info("sm: store remote CSRK"); 1535 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1536 le_device_db_remote_counter_set(le_db_index, 0); 1537 } 1538 #endif 1539 // store encryption information for secure connections: LTK generated by ECDH 1540 if (setup->sm_use_secure_connections){ 1541 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1542 uint8_t zero_rand[8]; 1543 memset(zero_rand, 0, 8); 1544 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1545 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1546 } 1547 1548 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1549 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1550 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1551 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1552 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1553 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1554 1555 } 1556 } 1557 } 1558 1559 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1560 sm_conn->sm_pairing_failed_reason = reason; 1561 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1562 } 1563 1564 static int sm_le_device_db_index_lookup(bd_addr_type_t address_type, bd_addr_t address){ 1565 int i; 1566 for (i=0; i < le_device_db_max_count(); i++){ 1567 bd_addr_t db_address; 1568 int db_address_type = BD_ADDR_TYPE_UNKNOWN; 1569 le_device_db_info(i, &db_address_type, db_address, NULL); 1570 // skip unused entries 1571 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1572 if ((address_type == (unsigned int)db_address_type) && (memcmp(address, db_address, 6) == 0)){ 1573 return i; 1574 } 1575 } 1576 return -1; 1577 } 1578 1579 static void sm_remove_le_device_db_entry(uint16_t i) { 1580 le_device_db_remove(i); 1581 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1582 // to remove an entry from the resolving list requires its identity address, which was already deleted 1583 // fully reload resolving list instead 1584 gap_load_resolving_list_from_le_device_db(); 1585 #endif 1586 } 1587 1588 static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){ 1589 UNUSED(sm_conn); 1590 1591 // if identity is provided, abort if we have bonding with same address but different irk 1592 if ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 1593 int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, setup->sm_peer_address); 1594 if (index >= 0){ 1595 sm_key_t irk; 1596 le_device_db_info(index, NULL, NULL, irk); 1597 if (memcmp(irk, setup->sm_peer_irk, 16) != 0){ 1598 // IRK doesn't match, delete bonding information 1599 log_info("New IRK for %s (type %u) does not match stored IRK -> delete bonding information", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); 1600 sm_remove_le_device_db_entry(index); 1601 } 1602 } 1603 } 1604 return 0; 1605 } 1606 1607 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1608 1609 // abort pairing if received keys are not valid 1610 uint8_t reason = sm_key_distribution_validate_received(sm_conn); 1611 if (reason != 0){ 1612 sm_pairing_error(sm_conn, reason); 1613 return; 1614 } 1615 1616 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1617 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1618 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1619 & SM_AUTHREQ_BONDING ) != 0u; 1620 1621 if (bonding_enabled){ 1622 sm_store_bonding_information(sm_conn); 1623 } else { 1624 log_info("Ignoring received keys, bonding not enabled"); 1625 } 1626 } 1627 1628 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1629 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1630 } 1631 1632 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1633 1634 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1635 static bool sm_passkey_used(stk_generation_method_t method); 1636 static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1637 static void sm_sc_generate_nx_for_send_random(sm_connection_t * sm_conn); 1638 1639 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1640 if (setup->sm_stk_generation_method == OOB){ 1641 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1642 } else { 1643 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); 1644 } 1645 } 1646 1647 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1648 if (IS_RESPONDER(sm_conn->sm_role)){ 1649 // Responder 1650 if (setup->sm_stk_generation_method == OOB){ 1651 sm_sc_generate_nx_for_send_random(sm_conn); 1652 } else { 1653 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1654 } 1655 } else { 1656 // Initiator role 1657 switch (setup->sm_stk_generation_method){ 1658 case JUST_WORKS: 1659 sm_sc_prepare_dhkey_check(sm_conn); 1660 break; 1661 1662 case NUMERIC_COMPARISON: 1663 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1664 break; 1665 case PK_INIT_INPUT: 1666 case PK_RESP_INPUT: 1667 case PK_BOTH_INPUT: 1668 if (setup->sm_passkey_bit < 20u) { 1669 sm_sc_start_calculating_local_confirm(sm_conn); 1670 } else { 1671 sm_sc_prepare_dhkey_check(sm_conn); 1672 } 1673 break; 1674 case OOB: 1675 sm_sc_prepare_dhkey_check(sm_conn); 1676 break; 1677 default: 1678 btstack_assert(false); 1679 break; 1680 } 1681 } 1682 } 1683 1684 static void sm_sc_cmac_done(uint8_t * hash){ 1685 log_info("sm_sc_cmac_done: "); 1686 log_info_hexdump(hash, 16); 1687 1688 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1689 sm_sc_oob_state = SM_SC_OOB_IDLE; 1690 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1691 return; 1692 } 1693 1694 sm_connection_t * sm_conn = sm_cmac_connection; 1695 sm_cmac_connection = NULL; 1696 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1697 link_key_type_t link_key_type; 1698 #endif 1699 1700 switch (sm_conn->sm_engine_state){ 1701 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1702 (void)memcpy(setup->sm_local_confirm, hash, 16); 1703 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1704 break; 1705 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1706 // check 1707 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1708 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1709 break; 1710 } 1711 // for OOB, C is verified before generating and sending random Nonce 1712 if (setup->sm_stk_generation_method == OOB){ 1713 sm_sc_generate_nx_for_send_random(sm_conn); 1714 } else { 1715 sm_sc_state_after_receiving_random(sm_conn); 1716 } 1717 break; 1718 case SM_SC_W4_CALCULATE_G2: { 1719 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1720 big_endian_store_32(setup->sm_tk, 12, vab); 1721 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1722 sm_trigger_user_response(sm_conn); 1723 break; 1724 } 1725 case SM_SC_W4_CALCULATE_F5_SALT: 1726 (void)memcpy(setup->sm_t, hash, 16); 1727 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1728 break; 1729 case SM_SC_W4_CALCULATE_F5_MACKEY: 1730 (void)memcpy(setup->sm_mackey, hash, 16); 1731 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1732 break; 1733 case SM_SC_W4_CALCULATE_F5_LTK: 1734 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1735 // Errata Service Release to the Bluetooth Specification: ESR09 1736 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1737 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1738 (void)memcpy(setup->sm_ltk, hash, 16); 1739 (void)memcpy(setup->sm_local_ltk, hash, 16); 1740 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1741 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1742 break; 1743 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1744 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1745 if (IS_RESPONDER(sm_conn->sm_role)){ 1746 // responder 1747 if ((setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED) != 0u){ 1748 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1749 } else { 1750 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1751 } 1752 } else { 1753 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1754 } 1755 break; 1756 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1757 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1758 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1759 break; 1760 } 1761 if (IS_RESPONDER(sm_conn->sm_role)){ 1762 // responder 1763 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1764 } else { 1765 // initiator 1766 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1767 } 1768 break; 1769 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1770 case SM_SC_W4_CALCULATE_ILK: 1771 (void)memcpy(setup->sm_t, hash, 16); 1772 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1773 break; 1774 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1775 reverse_128(hash, setup->sm_t); 1776 link_key_type = sm_conn->sm_connection_authenticated ? 1777 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1778 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1779 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1780 if (IS_RESPONDER(sm_conn->sm_role)){ 1781 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1782 } else { 1783 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1784 } 1785 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1786 sm_done_for_handle(sm_conn->sm_handle); 1787 break; 1788 case SM_BR_EDR_W4_CALCULATE_ILK: 1789 (void)memcpy(setup->sm_t, hash, 16); 1790 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1791 break; 1792 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1793 log_info("Derived LE LTK from BR/EDR Link Key"); 1794 log_info_key("Link Key", hash); 1795 (void)memcpy(setup->sm_ltk, hash, 16); 1796 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1797 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1798 sm_store_bonding_information(sm_conn); 1799 sm_done_for_handle(sm_conn->sm_handle); 1800 break; 1801 #endif 1802 default: 1803 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1804 break; 1805 } 1806 sm_trigger_run(); 1807 } 1808 1809 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){ 1810 const uint16_t message_len = 65; 1811 sm_cmac_connection = sm_conn; 1812 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1813 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1814 sm_cmac_sc_buffer[64] = z; 1815 log_info("f4 key"); 1816 log_info_hexdump(x, 16); 1817 log_info("f4 message"); 1818 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1819 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1820 } 1821 1822 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1823 static const uint8_t f5_length[] = { 0x01, 0x00}; 1824 1825 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1826 1827 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1828 1829 log_info("f5_calculate_salt"); 1830 // calculate salt for f5 1831 const uint16_t message_len = 32; 1832 sm_cmac_connection = sm_conn; 1833 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1834 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1835 } 1836 1837 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){ 1838 const uint16_t message_len = 53; 1839 sm_cmac_connection = sm_conn; 1840 1841 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1842 sm_cmac_sc_buffer[0] = 0; 1843 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1844 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1845 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1846 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1847 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1848 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1849 log_info("f5 key"); 1850 log_info_hexdump(t, 16); 1851 log_info("f5 message for MacKey"); 1852 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1853 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1854 } 1855 1856 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1857 sm_key56_t bd_addr_master, bd_addr_slave; 1858 bd_addr_master[0] = setup->sm_m_addr_type; 1859 bd_addr_slave[0] = setup->sm_s_addr_type; 1860 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1861 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1862 if (IS_RESPONDER(sm_conn->sm_role)){ 1863 // responder 1864 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1865 } else { 1866 // initiator 1867 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1868 } 1869 } 1870 1871 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1872 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1873 const uint16_t message_len = 53; 1874 sm_cmac_connection = sm_conn; 1875 sm_cmac_sc_buffer[0] = 1; 1876 // 1..52 setup before 1877 log_info("f5 key"); 1878 log_info_hexdump(t, 16); 1879 log_info("f5 message for LTK"); 1880 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1881 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1882 } 1883 1884 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1885 f5_ltk(sm_conn, setup->sm_t); 1886 } 1887 1888 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){ 1889 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1890 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1891 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1892 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1893 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1894 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1895 } 1896 1897 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1898 const uint16_t message_len = 65; 1899 sm_cmac_connection = sm_conn; 1900 log_info("f6 key"); 1901 log_info_hexdump(w, 16); 1902 log_info("f6 message"); 1903 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1904 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1905 } 1906 1907 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1908 // - U is 256 bits 1909 // - V is 256 bits 1910 // - X is 128 bits 1911 // - Y is 128 bits 1912 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){ 1913 const uint16_t message_len = 80; 1914 sm_cmac_connection = sm_conn; 1915 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1916 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1917 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1918 log_info("g2 key"); 1919 log_info_hexdump(x, 16); 1920 log_info("g2 message"); 1921 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1922 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1923 } 1924 1925 static void g2_calculate(sm_connection_t * sm_conn) { 1926 // calc Va if numeric comparison 1927 if (IS_RESPONDER(sm_conn->sm_role)){ 1928 // responder 1929 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1930 } else { 1931 // initiator 1932 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1933 } 1934 } 1935 1936 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1937 uint8_t z = 0; 1938 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1939 // some form of passkey 1940 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1941 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1942 setup->sm_passkey_bit++; 1943 } 1944 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1945 } 1946 1947 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1948 // OOB 1949 if (setup->sm_stk_generation_method == OOB){ 1950 if (IS_RESPONDER(sm_conn->sm_role)){ 1951 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1952 } else { 1953 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1954 } 1955 return; 1956 } 1957 1958 uint8_t z = 0; 1959 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1960 // some form of passkey 1961 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1962 // sm_passkey_bit was increased before sending confirm value 1963 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1964 } 1965 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1966 } 1967 1968 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1969 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) != 0 ? 1 : 0); 1970 1971 if ((setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) != 0u){ 1972 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1973 } else { 1974 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1975 } 1976 } 1977 1978 static void sm_sc_dhkey_calculated(void * arg){ 1979 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1980 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1981 if (sm_conn == NULL) return; 1982 1983 // check for invalid public key detected by Controller 1984 if (sm_is_ff(setup->sm_dhkey, 32)){ 1985 log_info("sm: peer public key invalid"); 1986 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1987 return; 1988 } 1989 1990 log_info("dhkey"); 1991 log_info_hexdump(&setup->sm_dhkey[0], 32); 1992 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1993 // trigger next step 1994 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1995 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1996 } 1997 sm_trigger_run(); 1998 } 1999 2000 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 2001 // calculate DHKCheck 2002 sm_key56_t bd_addr_master, bd_addr_slave; 2003 bd_addr_master[0] = setup->sm_m_addr_type; 2004 bd_addr_slave[0] = setup->sm_s_addr_type; 2005 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2006 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2007 uint8_t iocap_a[3]; 2008 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2009 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2010 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2011 uint8_t iocap_b[3]; 2012 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2013 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2014 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2015 if (IS_RESPONDER(sm_conn->sm_role)){ 2016 // responder 2017 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2018 f6_engine(sm_conn, setup->sm_mackey); 2019 } else { 2020 // initiator 2021 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2022 f6_engine(sm_conn, setup->sm_mackey); 2023 } 2024 } 2025 2026 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 2027 // validate E = f6() 2028 sm_key56_t bd_addr_master, bd_addr_slave; 2029 bd_addr_master[0] = setup->sm_m_addr_type; 2030 bd_addr_slave[0] = setup->sm_s_addr_type; 2031 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2032 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2033 2034 uint8_t iocap_a[3]; 2035 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2036 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2037 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2038 uint8_t iocap_b[3]; 2039 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2040 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2041 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2042 if (IS_RESPONDER(sm_conn->sm_role)){ 2043 // responder 2044 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2045 f6_engine(sm_conn, setup->sm_mackey); 2046 } else { 2047 // initiator 2048 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2049 f6_engine(sm_conn, setup->sm_mackey); 2050 } 2051 } 2052 2053 static void sm_sc_generate_nx_for_send_random(sm_connection_t * sm_conn){ 2054 // generate Nx 2055 log_info("Generate N%c", IS_RESPONDER(sm_conn->sm_role) ? 'b' : 'a'); 2056 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); 2057 } 2058 2059 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2060 2061 // 2062 // Link Key Conversion Function h6 2063 // 2064 // h6(W, keyID) = AES-CMAC_W(keyID) 2065 // - W is 128 bits 2066 // - keyID is 32 bits 2067 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 2068 const uint16_t message_len = 4; 2069 sm_cmac_connection = sm_conn; 2070 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 2071 log_info("h6 key"); 2072 log_info_hexdump(w, 16); 2073 log_info("h6 message"); 2074 log_info_hexdump(sm_cmac_sc_buffer, message_len); 2075 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 2076 } 2077 // 2078 // Link Key Conversion Function h7 2079 // 2080 // h7(SALT, W) = AES-CMAC_SALT(W) 2081 // - SALT is 128 bits 2082 // - W is 128 bits 2083 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 2084 const uint16_t message_len = 16; 2085 sm_cmac_connection = sm_conn; 2086 log_info("h7 key"); 2087 log_info_hexdump(salt, 16); 2088 log_info("h7 message"); 2089 log_info_hexdump(w, 16); 2090 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 2091 } 2092 2093 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2094 // Errata Service Release to the Bluetooth Specification: ESR09 2095 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2096 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2097 2098 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2099 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2100 } 2101 2102 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2103 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2104 } 2105 2106 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2107 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2108 } 2109 2110 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2111 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2112 } 2113 2114 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2115 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2116 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2117 } 2118 2119 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2120 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2121 h7_engine(sm_conn, salt, setup->sm_link_key); 2122 } 2123 2124 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2125 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2126 btstack_assert(hci_connection != NULL); 2127 reverse_128(hci_connection->link_key, setup->sm_link_key); 2128 setup->sm_link_key_type = hci_connection->link_key_type; 2129 } 2130 2131 static void sm_ctkd_start_from_br_edr(sm_connection_t * sm_conn){ 2132 // only derive LTK if EncKey is set by both 2133 bool derive_ltk = (sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & 2134 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & SM_KEYDIST_ENC_KEY) != 0; 2135 if (derive_ltk){ 2136 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; 2137 sm_conn->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2138 } else { 2139 sm_done_for_handle(sm_conn->sm_handle); 2140 } 2141 } 2142 2143 #endif 2144 2145 #endif 2146 2147 // key management legacy connections: 2148 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2149 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2150 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2151 // - responder reconnects: responder uses LTK receveived from master 2152 2153 // key management secure connections: 2154 // - both devices store same LTK from ECDH key exchange. 2155 2156 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2157 static void sm_load_security_info(sm_connection_t * sm_connection){ 2158 int encryption_key_size; 2159 int authenticated; 2160 int authorized; 2161 int secure_connection; 2162 2163 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2164 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2165 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2166 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); 2167 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2168 sm_connection->sm_connection_authenticated = authenticated; 2169 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2170 sm_connection->sm_connection_sc = secure_connection != 0; 2171 } 2172 #endif 2173 2174 #ifdef ENABLE_LE_PERIPHERAL 2175 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2176 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2177 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2178 // re-establish used key encryption size 2179 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2180 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2181 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2182 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2183 // Legacy paring -> not SC 2184 sm_connection->sm_connection_sc = false; 2185 log_info("sm: received ltk request with key size %u, authenticated %u", 2186 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2187 } 2188 #endif 2189 2190 // distributed key generation 2191 static bool sm_run_dpkg(void){ 2192 switch (dkg_state){ 2193 case DKG_CALC_IRK: 2194 // already busy? 2195 if (sm_aes128_state == SM_AES128_IDLE) { 2196 log_info("DKG_CALC_IRK started"); 2197 // IRK = d1(IR, 1, 0) 2198 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2199 sm_aes128_state = SM_AES128_ACTIVE; 2200 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2201 return true; 2202 } 2203 break; 2204 case DKG_CALC_DHK: 2205 // already busy? 2206 if (sm_aes128_state == SM_AES128_IDLE) { 2207 log_info("DKG_CALC_DHK started"); 2208 // DHK = d1(IR, 3, 0) 2209 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2210 sm_aes128_state = SM_AES128_ACTIVE; 2211 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2212 return true; 2213 } 2214 break; 2215 default: 2216 break; 2217 } 2218 return false; 2219 } 2220 2221 // random address updates 2222 static bool sm_run_rau(void){ 2223 switch (rau_state){ 2224 case RAU_GET_RANDOM: 2225 rau_state = RAU_W4_RANDOM; 2226 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2227 return true; 2228 case RAU_GET_ENC: 2229 // already busy? 2230 if (sm_aes128_state == SM_AES128_IDLE) { 2231 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2232 sm_aes128_state = SM_AES128_ACTIVE; 2233 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2234 return true; 2235 } 2236 break; 2237 default: 2238 break; 2239 } 2240 return false; 2241 } 2242 2243 // device lookup with IRK 2244 static bool sm_run_irk_lookup(void){ 2245 btstack_linked_list_iterator_t it; 2246 2247 // -- if IRK lookup ready, find connection that require csrk lookup 2248 if (sm_address_resolution_idle()){ 2249 hci_connections_get_iterator(&it); 2250 while(btstack_linked_list_iterator_has_next(&it)){ 2251 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2252 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2253 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2254 // and start lookup 2255 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); 2256 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2257 break; 2258 } 2259 } 2260 } 2261 2262 // -- if csrk lookup ready, resolved addresses for received addresses 2263 if (sm_address_resolution_idle()) { 2264 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2265 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2266 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2267 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2268 btstack_memory_sm_lookup_entry_free(entry); 2269 } 2270 } 2271 2272 // -- Continue with device lookup by public or resolvable private address 2273 if (!sm_address_resolution_idle()){ 2274 bool started_aes128 = false; 2275 while (sm_address_resolution_test < le_device_db_max_count()){ 2276 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2277 bd_addr_t addr; 2278 sm_key_t irk; 2279 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2280 2281 // skip unused entries 2282 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2283 sm_address_resolution_test++; 2284 continue; 2285 } 2286 2287 log_info("LE Device Lookup: device %u of %u - type %u, %s", sm_address_resolution_test, 2288 le_device_db_max_count(), addr_type, bd_addr_to_str(addr)); 2289 2290 // map resolved identity addresses to regular addresses 2291 int regular_addr_type = sm_address_resolution_addr_type & 1; 2292 if ((regular_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2293 log_info("LE Device Lookup: found by { addr_type, address} "); 2294 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2295 break; 2296 } 2297 2298 // if connection type is not random (i.e. public or resolved identity), it must be a different entry 2299 if (sm_address_resolution_addr_type != BD_ADDR_TYPE_LE_RANDOM){ 2300 sm_address_resolution_test++; 2301 continue; 2302 } 2303 2304 // skip AH if no IRK 2305 if (sm_is_null_key(irk)){ 2306 sm_address_resolution_test++; 2307 continue; 2308 } 2309 2310 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2311 2312 log_info("LE Device Lookup: calculate AH"); 2313 log_info_key("IRK", irk); 2314 2315 (void)memcpy(sm_aes128_key, irk, 16); 2316 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2317 sm_aes128_state = SM_AES128_ACTIVE; 2318 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2319 started_aes128 = true; 2320 break; 2321 } 2322 2323 if (started_aes128){ 2324 return true; 2325 } 2326 2327 if (sm_address_resolution_test >= le_device_db_max_count()){ 2328 log_info("LE Device Lookup: not found"); 2329 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2330 } 2331 } 2332 return false; 2333 } 2334 2335 // SC OOB 2336 static bool sm_run_oob(void){ 2337 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2338 switch (sm_sc_oob_state){ 2339 case SM_SC_OOB_W2_CALC_CONFIRM: 2340 if (!sm_cmac_ready()) break; 2341 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2342 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2343 return true; 2344 default: 2345 break; 2346 } 2347 #endif 2348 return false; 2349 } 2350 2351 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2352 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2353 } 2354 2355 // handle basic actions that don't requires the full context 2356 static bool sm_run_basic(void){ 2357 btstack_linked_list_iterator_t it; 2358 hci_connections_get_iterator(&it); 2359 while(btstack_linked_list_iterator_has_next(&it)){ 2360 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2361 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2362 switch(sm_connection->sm_engine_state){ 2363 2364 // general 2365 case SM_GENERAL_SEND_PAIRING_FAILED: { 2366 uint8_t buffer[2]; 2367 buffer[0] = SM_CODE_PAIRING_FAILED; 2368 buffer[1] = sm_connection->sm_pairing_failed_reason; 2369 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2370 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2371 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2372 sm_done_for_handle(sm_connection->sm_handle); 2373 break; 2374 } 2375 2376 // responder side 2377 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2378 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2379 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2380 return true; 2381 2382 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2383 case SM_SC_RECEIVED_LTK_REQUEST: 2384 switch (sm_connection->sm_irk_lookup_state){ 2385 case IRK_LOOKUP_FAILED: 2386 log_info("LTK Request: IRK Lookup Failed)"); 2387 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2388 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2389 return true; 2390 default: 2391 break; 2392 } 2393 break; 2394 #endif 2395 default: 2396 break; 2397 } 2398 } 2399 return false; 2400 } 2401 2402 static void sm_run_activate_connection(void){ 2403 // Find connections that requires setup context and make active if no other is locked 2404 btstack_linked_list_iterator_t it; 2405 hci_connections_get_iterator(&it); 2406 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2407 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2408 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2409 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2410 bool done = true; 2411 2412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2413 // assert ec key is ready 2414 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2415 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2416 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2417 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2418 sm_ec_generate_new_key(); 2419 } 2420 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2421 continue; 2422 } 2423 } 2424 #endif 2425 2426 switch (sm_connection->sm_engine_state) { 2427 #ifdef ENABLE_LE_PERIPHERAL 2428 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2429 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2430 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2431 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2432 case SM_SC_RECEIVED_LTK_REQUEST: 2433 #endif 2434 #endif 2435 #ifdef ENABLE_LE_CENTRAL 2436 case SM_INITIATOR_PH4_HAS_LTK: 2437 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2438 #endif 2439 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2440 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2441 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2442 #endif 2443 // just lock context 2444 break; 2445 default: 2446 done = false; 2447 break; 2448 } 2449 if (done){ 2450 sm_active_connection_handle = sm_connection->sm_handle; 2451 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); 2452 } 2453 } 2454 } 2455 2456 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2457 int i; 2458 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2459 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2460 uint8_t action = 0; 2461 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2462 if ((flags & (1u<<i)) != 0u){ 2463 bool clear_flag = true; 2464 switch (i){ 2465 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2466 case SM_KEYPRESS_PASSKEY_CLEARED: 2467 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2468 default: 2469 break; 2470 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2471 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2472 num_actions--; 2473 clear_flag = num_actions == 0u; 2474 break; 2475 } 2476 if (clear_flag){ 2477 flags &= ~(1<<i); 2478 } 2479 action = i; 2480 break; 2481 } 2482 } 2483 setup->sm_keypress_notification = (num_actions << 5) | flags; 2484 2485 // send keypress notification 2486 uint8_t buffer[2]; 2487 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2488 buffer[1] = action; 2489 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2490 2491 // try 2492 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2493 } 2494 2495 static void sm_run_distribute_keys(sm_connection_t * connection){ 2496 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) != 0u){ 2497 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2498 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2499 uint8_t buffer[17]; 2500 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2501 reverse_128(setup->sm_ltk, &buffer[1]); 2502 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2503 sm_timeout_reset(connection); 2504 return; 2505 } 2506 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION) != 0u){ 2507 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2508 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2509 uint8_t buffer[11]; 2510 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2511 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2512 reverse_64(setup->sm_local_rand, &buffer[3]); 2513 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2514 sm_timeout_reset(connection); 2515 return; 2516 } 2517 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 2518 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2519 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2520 uint8_t buffer[17]; 2521 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2522 reverse_128(sm_persistent_irk, &buffer[1]); 2523 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2524 sm_timeout_reset(connection); 2525 return; 2526 } 2527 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0u){ 2528 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2529 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2530 bd_addr_t local_address; 2531 uint8_t buffer[8]; 2532 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2533 switch (gap_random_address_get_mode()){ 2534 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2535 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2536 // public or static random 2537 gap_le_get_own_address(&buffer[1], local_address); 2538 break; 2539 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2540 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2541 // fallback to public 2542 gap_local_bd_addr(local_address); 2543 buffer[1] = 0; 2544 break; 2545 default: 2546 btstack_assert(false); 2547 break; 2548 } 2549 reverse_bd_addr(local_address, &buffer[2]); 2550 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2551 sm_timeout_reset(connection); 2552 return; 2553 } 2554 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION) != 0u){ 2555 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2556 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2557 2558 #ifdef ENABLE_LE_SIGNED_WRITE 2559 // hack to reproduce test runs 2560 if (test_use_fixed_local_csrk){ 2561 memset(setup->sm_local_csrk, 0xcc, 16); 2562 } 2563 2564 // store local CSRK 2565 if (setup->sm_le_device_index >= 0){ 2566 log_info("sm: store local CSRK"); 2567 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2568 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2569 } 2570 #endif 2571 2572 uint8_t buffer[17]; 2573 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2574 reverse_128(setup->sm_local_csrk, &buffer[1]); 2575 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2576 sm_timeout_reset(connection); 2577 return; 2578 } 2579 btstack_assert(false); 2580 } 2581 2582 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2583 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2584 // requirements to derive link key from LE: 2585 // - use secure connections 2586 if (setup->sm_use_secure_connections == 0) return false; 2587 // - bonding needs to be enabled: 2588 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; 2589 if (!bonding_enabled) return false; 2590 // - need identity address / public addr 2591 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2592 if (!have_identity_address_info) return false; 2593 // - 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) 2594 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2595 // If SC is authenticated, we consider it safe to overwrite a stored key. 2596 // 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. 2597 uint8_t link_key[16]; 2598 link_key_type_t link_key_type; 2599 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2600 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2601 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2602 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2603 return false; 2604 } 2605 // get started (all of the above are true) 2606 return true; 2607 #else 2608 UNUSED(sm_connection); 2609 return false; 2610 #endif 2611 } 2612 2613 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2614 static bool sm_ctkd_from_classic(sm_connection_t * sm_connection){ 2615 hci_connection_t * hci_connection = hci_connection_for_handle(sm_connection->sm_handle); 2616 btstack_assert(hci_connection != NULL); 2617 // requirements to derive ltk from BR/EDR: 2618 // - BR/EDR uses secure connections 2619 if (gap_secure_connection_for_link_key_type(hci_connection->link_key_type) == false) return false; 2620 // - there is no stored LTK or the derived key has at least the same level of authentication (bail if LTK is authenticated but Link Key isn't) 2621 bool link_key_authenticated = gap_authenticated_for_link_key_type(hci_connection->link_key_type); 2622 if (link_key_authenticated) return true; 2623 int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, hci_connection->address); 2624 if (index >= 0){ 2625 int ltk_authenticated; 2626 sm_key_t ltk; 2627 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, <k_authenticated, NULL, NULL); 2628 bool have_ltk = !sm_is_null_key(ltk); 2629 if (have_ltk && ltk_authenticated) return false; 2630 } 2631 return true; 2632 } 2633 #endif 2634 2635 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2636 if (sm_ctkd_from_le(connection)){ 2637 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; 2638 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2639 } else { 2640 connection->sm_engine_state = SM_RESPONDER_IDLE; 2641 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2642 sm_done_for_handle(connection->sm_handle); 2643 } 2644 } 2645 2646 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2647 if (sm_ctkd_from_le(connection)){ 2648 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; 2649 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2650 } else { 2651 sm_master_pairing_success(connection); 2652 } 2653 } 2654 2655 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2656 static void sm_run_state_sc_send_confirmation(sm_connection_t *connection) { 2657 uint8_t buffer[17]; 2658 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2659 reverse_128(setup->sm_local_confirm, &buffer[1]); 2660 if (IS_RESPONDER(connection->sm_role)){ 2661 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2662 } else { 2663 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2664 } 2665 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2666 sm_timeout_reset(connection); 2667 } 2668 2669 static void sm_run_state_sc_send_pairing_random(sm_connection_t *connection) { 2670 uint8_t buffer[17]; 2671 buffer[0] = SM_CODE_PAIRING_RANDOM; 2672 reverse_128(setup->sm_local_nonce, &buffer[1]); 2673 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2674 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2675 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2676 if (IS_RESPONDER(connection->sm_role)){ 2677 // responder 2678 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2679 } else { 2680 // initiator 2681 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2682 } 2683 } else { 2684 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2685 if (IS_RESPONDER(connection->sm_role)){ 2686 // responder 2687 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2688 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2689 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2690 } else { 2691 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2692 sm_sc_prepare_dhkey_check(connection); 2693 } 2694 } else { 2695 // initiator 2696 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2697 } 2698 } 2699 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2700 sm_timeout_reset(connection); 2701 } 2702 2703 static void sm_run_state_sc_send_dhkey_check_command(sm_connection_t *connection) { 2704 uint8_t buffer[17]; 2705 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2706 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2707 2708 if (IS_RESPONDER(connection->sm_role)){ 2709 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2710 } else { 2711 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2712 } 2713 2714 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2715 sm_timeout_reset(connection); 2716 } 2717 2718 static void sm_run_state_sc_send_public_key_command(sm_connection_t *connection) { 2719 bool trigger_user_response = false; 2720 bool trigger_start_calculating_local_confirm = false; 2721 uint8_t buffer[65]; 2722 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2723 // 2724 reverse_256(&ec_q[0], &buffer[1]); 2725 reverse_256(&ec_q[32], &buffer[33]); 2726 2727 #ifdef ENABLE_TESTING_SUPPORT 2728 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2729 log_info("testing_support: invalidating public key"); 2730 // flip single bit of public key coordinate 2731 buffer[1] ^= 1; 2732 } 2733 #endif 2734 2735 // stk generation method 2736 // passkey entry: notify app to show passkey or to request passkey 2737 switch (setup->sm_stk_generation_method){ 2738 case JUST_WORKS: 2739 case NUMERIC_COMPARISON: 2740 if (IS_RESPONDER(connection->sm_role)){ 2741 // responder 2742 trigger_start_calculating_local_confirm = true; 2743 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2744 } else { 2745 // initiator 2746 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2747 } 2748 break; 2749 case PK_INIT_INPUT: 2750 case PK_RESP_INPUT: 2751 case PK_BOTH_INPUT: 2752 // use random TK for display 2753 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2754 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2755 setup->sm_passkey_bit = 0; 2756 2757 if (IS_RESPONDER(connection->sm_role)){ 2758 // responder 2759 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2760 } else { 2761 // initiator 2762 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2763 } 2764 trigger_user_response = true; 2765 break; 2766 case OOB: 2767 if (IS_RESPONDER(connection->sm_role)){ 2768 // responder 2769 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2770 } else { 2771 // initiator 2772 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2773 } 2774 break; 2775 default: 2776 btstack_assert(false); 2777 break; 2778 } 2779 2780 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2781 sm_timeout_reset(connection); 2782 2783 // trigger user response and calc confirm after sending pdu 2784 if (trigger_user_response){ 2785 sm_trigger_user_response(connection); 2786 } 2787 if (trigger_start_calculating_local_confirm){ 2788 sm_sc_start_calculating_local_confirm(connection); 2789 } 2790 } 2791 #endif 2792 2793 static bool sm_run_non_connection_logic(void){ 2794 bool done;; 2795 2796 done = sm_run_dpkg(); 2797 if (done) return true; 2798 2799 done = sm_run_rau(); 2800 if (done) return true; 2801 2802 done = sm_run_irk_lookup(); 2803 if (done) return true; 2804 2805 done = sm_run_oob(); 2806 return done; 2807 } 2808 2809 static bool sm_run_ready(void) { 2810 // assert that stack has already booted 2811 if (hci_get_state() != HCI_STATE_WORKING) return false; 2812 2813 // assert that we can send at least commands 2814 if (!hci_can_send_command_packet_now()) return false; 2815 2816 // pause until IR/ER are ready 2817 if (sm_persistent_keys_random_active) return false; 2818 2819 return true; 2820 } 2821 2822 static void sm_run(void){ 2823 2824 // ready 2825 if (sm_run_ready() == false) return; 2826 2827 // non-connection related behaviour 2828 bool done = sm_run_non_connection_logic(); 2829 if (done) return; 2830 2831 // assert that we can send at least commands - cmd might have been sent by crypto engine 2832 if (!hci_can_send_command_packet_now()) return; 2833 2834 // handle basic actions that don't requires the full context 2835 done = sm_run_basic(); 2836 if (done) return; 2837 2838 // 2839 // active connection handling 2840 // -- use loop to handle next connection if lock on setup context is released 2841 2842 while (true) { 2843 2844 sm_run_activate_connection(); 2845 2846 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2847 2848 // 2849 // active connection handling 2850 // 2851 2852 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2853 if (!connection) { 2854 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2855 return; 2856 } 2857 2858 // assert that we could send a SM PDU - not needed for all of the following 2859 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2860 log_info("cannot send now, requesting can send now event"); 2861 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2862 return; 2863 } 2864 2865 // send keypress notifications 2866 if (setup->sm_keypress_notification != 0u){ 2867 sm_run_send_keypress_notification(connection); 2868 return; 2869 } 2870 2871 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2872 // assert that sm cmac engine is ready 2873 if (sm_cmac_ready() == false){ 2874 break; 2875 } 2876 #endif 2877 2878 // initialize to avoid 'maybe used uninitialized' error 2879 int key_distribution_flags = 0; 2880 UNUSED(key_distribution_flags); 2881 #ifdef ENABLE_LE_PERIPHERAL 2882 int err; 2883 bool have_ltk; 2884 uint8_t ltk[16]; 2885 #endif 2886 2887 log_info("sm_run: state %u", connection->sm_engine_state); 2888 switch (connection->sm_engine_state){ 2889 2890 // secure connections, initiator + responding states 2891 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2892 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2893 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2894 sm_sc_calculate_local_confirm(connection); 2895 break; 2896 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2897 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2898 sm_sc_calculate_remote_confirm(connection); 2899 break; 2900 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2901 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2902 sm_sc_calculate_f6_for_dhkey_check(connection); 2903 break; 2904 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2905 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2906 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2907 break; 2908 case SM_SC_W2_CALCULATE_F5_SALT: 2909 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2910 f5_calculate_salt(connection); 2911 break; 2912 case SM_SC_W2_CALCULATE_F5_MACKEY: 2913 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2914 f5_calculate_mackey(connection); 2915 break; 2916 case SM_SC_W2_CALCULATE_F5_LTK: 2917 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2918 f5_calculate_ltk(connection); 2919 break; 2920 case SM_SC_W2_CALCULATE_G2: 2921 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2922 g2_calculate(connection); 2923 break; 2924 #endif 2925 2926 #ifdef ENABLE_LE_CENTRAL 2927 // initiator side 2928 2929 case SM_INITIATOR_PH4_HAS_LTK: { 2930 sm_reset_setup(); 2931 sm_load_security_info(connection); 2932 2933 // cache key before using 2934 sm_cache_ltk(connection, setup->sm_peer_ltk); 2935 2936 sm_key_t peer_ltk_flipped; 2937 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2938 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2939 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2940 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2941 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2942 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2943 2944 // notify after sending 2945 sm_reencryption_started(connection); 2946 return; 2947 } 2948 2949 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2950 sm_reset_setup(); 2951 sm_init_setup(connection); 2952 2953 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2954 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2955 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2956 sm_timeout_reset(connection); 2957 2958 // notify after sending 2959 sm_pairing_started(connection); 2960 break; 2961 #endif 2962 2963 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2964 case SM_SC_SEND_PUBLIC_KEY_COMMAND: 2965 sm_run_state_sc_send_public_key_command(connection); 2966 break; 2967 case SM_SC_SEND_CONFIRMATION: 2968 sm_run_state_sc_send_confirmation(connection); 2969 break; 2970 case SM_SC_SEND_PAIRING_RANDOM: 2971 sm_run_state_sc_send_pairing_random(connection); 2972 break; 2973 case SM_SC_SEND_DHKEY_CHECK_COMMAND: 2974 sm_run_state_sc_send_dhkey_check_command(connection); 2975 break; 2976 #endif 2977 2978 #ifdef ENABLE_LE_PERIPHERAL 2979 2980 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2981 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2982 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2983 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2984 sm_timeout_start(connection); 2985 break; 2986 } 2987 2988 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2989 case SM_SC_RECEIVED_LTK_REQUEST: 2990 switch (connection->sm_irk_lookup_state){ 2991 case IRK_LOOKUP_SUCCEEDED: 2992 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2993 // start using context by loading security info 2994 sm_reset_setup(); 2995 sm_load_security_info(connection); 2996 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2997 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2998 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2999 sm_reencryption_started(connection); 3000 sm_trigger_run(); 3001 break; 3002 } 3003 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 3004 connection->sm_engine_state = SM_RESPONDER_IDLE; 3005 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 3006 return; 3007 default: 3008 // just wait until IRK lookup is completed 3009 break; 3010 } 3011 break; 3012 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 3013 3014 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 3015 sm_reset_setup(); 3016 3017 // handle Pairing Request with LTK available 3018 switch (connection->sm_irk_lookup_state) { 3019 case IRK_LOOKUP_SUCCEEDED: 3020 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3021 have_ltk = !sm_is_null_key(ltk); 3022 if (have_ltk){ 3023 log_info("pairing request but LTK available"); 3024 // emit re-encryption start/fail sequence 3025 sm_reencryption_started(connection); 3026 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 3027 } 3028 break; 3029 default: 3030 break; 3031 } 3032 3033 sm_init_setup(connection); 3034 3035 // recover pairing request 3036 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3037 err = sm_stk_generation_init(connection); 3038 3039 #ifdef ENABLE_TESTING_SUPPORT 3040 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 3041 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 3042 err = test_pairing_failure; 3043 } 3044 #endif 3045 if (err != 0){ 3046 // emit pairing started/failed sequence 3047 sm_pairing_started(connection); 3048 sm_pairing_error(connection, err); 3049 sm_trigger_run(); 3050 break; 3051 } 3052 3053 sm_timeout_start(connection); 3054 3055 // generate random number first, if we need to show passkey, otherwise send response 3056 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3057 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 3058 break; 3059 } 3060 3061 /* fall through */ 3062 3063 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 3064 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 3065 3066 // start with initiator key dist flags 3067 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 3068 3069 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3070 // LTK (= encryption information & master identification) only exchanged for LE Legacy Connection 3071 if (setup->sm_use_secure_connections){ 3072 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3073 } 3074 #endif 3075 // setup in response 3076 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); 3077 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); 3078 3079 // update key distribution after ENC was dropped 3080 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)); 3081 3082 if (setup->sm_use_secure_connections){ 3083 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 3084 } else { 3085 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 3086 } 3087 3088 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3089 sm_timeout_reset(connection); 3090 3091 // notify after sending 3092 sm_pairing_started(connection); 3093 3094 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3095 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 3096 sm_trigger_user_response(connection); 3097 } 3098 return; 3099 #endif 3100 3101 case SM_PH2_SEND_PAIRING_RANDOM: { 3102 uint8_t buffer[17]; 3103 buffer[0] = SM_CODE_PAIRING_RANDOM; 3104 reverse_128(setup->sm_local_random, &buffer[1]); 3105 if (IS_RESPONDER(connection->sm_role)){ 3106 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 3107 } else { 3108 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 3109 } 3110 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3111 sm_timeout_reset(connection); 3112 break; 3113 } 3114 3115 case SM_PH2_C1_GET_ENC_A: 3116 // already busy? 3117 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3118 // calculate confirm using aes128 engine - step 1 3119 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); 3120 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 3121 sm_aes128_state = SM_AES128_ACTIVE; 3122 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); 3123 break; 3124 3125 case SM_PH2_C1_GET_ENC_C: 3126 // already busy? 3127 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3128 // calculate m_confirm using aes128 engine - step 1 3129 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); 3130 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 3131 sm_aes128_state = SM_AES128_ACTIVE; 3132 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); 3133 break; 3134 3135 case SM_PH2_CALC_STK: 3136 // already busy? 3137 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3138 // calculate STK 3139 if (IS_RESPONDER(connection->sm_role)){ 3140 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 3141 } else { 3142 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3143 } 3144 connection->sm_engine_state = SM_PH2_W4_STK; 3145 sm_aes128_state = SM_AES128_ACTIVE; 3146 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); 3147 break; 3148 3149 case SM_PH3_Y_GET_ENC: 3150 // already busy? 3151 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3152 // PH3B2 - calculate Y from - enc 3153 3154 // dm helper (was sm_dm_r_prime) 3155 // r' = padding || r 3156 // r - 64 bit value 3157 memset(&sm_aes128_plaintext[0], 0, 8); 3158 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3159 3160 // Y = dm(DHK, Rand) 3161 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3162 sm_aes128_state = SM_AES128_ACTIVE; 3163 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); 3164 break; 3165 3166 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3167 uint8_t buffer[17]; 3168 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3169 reverse_128(setup->sm_local_confirm, &buffer[1]); 3170 if (IS_RESPONDER(connection->sm_role)){ 3171 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3172 } else { 3173 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3174 } 3175 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3176 sm_timeout_reset(connection); 3177 return; 3178 } 3179 #ifdef ENABLE_LE_PERIPHERAL 3180 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3181 // cache key before using 3182 sm_cache_ltk(connection, setup->sm_ltk); 3183 sm_key_t stk_flipped; 3184 reverse_128(setup->sm_ltk, stk_flipped); 3185 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3186 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3187 return; 3188 } 3189 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3190 // allow to override LTK 3191 if (sm_get_ltk_callback != NULL){ 3192 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3193 } 3194 // cache key before using 3195 sm_cache_ltk(connection, setup->sm_ltk); 3196 sm_key_t ltk_flipped; 3197 reverse_128(setup->sm_ltk, ltk_flipped); 3198 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3199 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3200 return; 3201 } 3202 3203 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3204 // already busy? 3205 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3206 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3207 3208 sm_reset_setup(); 3209 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3210 3211 sm_reencryption_started(connection); 3212 3213 // dm helper (was sm_dm_r_prime) 3214 // r' = padding || r 3215 // r - 64 bit value 3216 memset(&sm_aes128_plaintext[0], 0, 8); 3217 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3218 3219 // Y = dm(DHK, Rand) 3220 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3221 sm_aes128_state = SM_AES128_ACTIVE; 3222 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); 3223 return; 3224 #endif 3225 #ifdef ENABLE_LE_CENTRAL 3226 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3227 // cache key before using 3228 sm_cache_ltk(connection, setup->sm_ltk); 3229 3230 sm_key_t stk_flipped; 3231 reverse_128(setup->sm_ltk, stk_flipped); 3232 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3233 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3234 return; 3235 } 3236 #endif 3237 3238 case SM_PH3_DISTRIBUTE_KEYS: 3239 // send next key 3240 if (setup->sm_key_distribution_send_set != 0){ 3241 sm_run_distribute_keys(connection); 3242 } 3243 3244 // more to send? 3245 if (setup->sm_key_distribution_send_set != 0){ 3246 return; 3247 } 3248 3249 // keys are sent 3250 if (IS_RESPONDER(connection->sm_role)){ 3251 // slave -> receive master keys if any 3252 if (sm_key_distribution_all_received()){ 3253 sm_key_distribution_handle_all_received(connection); 3254 sm_key_distribution_complete_responder(connection); 3255 // start CTKD right away 3256 continue; 3257 } else { 3258 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3259 } 3260 } else { 3261 sm_master_pairing_success(connection); 3262 } 3263 break; 3264 3265 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3266 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3267 // fill in sm setup (lite version of sm_init_setup) 3268 sm_reset_setup(); 3269 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3270 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3271 setup->sm_s_addr_type = connection->sm_own_addr_type; 3272 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3273 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3274 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3275 setup->sm_use_secure_connections = true; 3276 sm_ctkd_fetch_br_edr_link_key(connection); 3277 3278 // Enc Key and IRK if requested 3279 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3280 #ifdef ENABLE_LE_SIGNED_WRITE 3281 // Plus signing key if supported 3282 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3283 #endif 3284 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3285 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3286 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3287 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3288 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3289 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3290 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3291 3292 // set state and send pairing response 3293 sm_timeout_start(connection); 3294 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3295 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3296 break; 3297 3298 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3299 // fill in sm setup (lite version of sm_init_setup) 3300 sm_reset_setup(); 3301 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3302 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3303 setup->sm_s_addr_type = connection->sm_own_addr_type; 3304 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3305 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3306 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3307 setup->sm_use_secure_connections = true; 3308 sm_ctkd_fetch_br_edr_link_key(connection); 3309 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3310 3311 // Enc Key and IRK if requested 3312 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3313 #ifdef ENABLE_LE_SIGNED_WRITE 3314 // Plus signing key if supported 3315 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3316 #endif 3317 // drop flags not requested by initiator 3318 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3319 3320 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3321 // - the IO Capability field, 3322 // - the OOB data flag field, and 3323 // - all bits in the Auth Req field except the CT2 bit. 3324 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3325 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3326 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3327 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3328 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3329 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3330 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3331 3332 // configure key distribution, LTK is derived locally 3333 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3334 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3335 3336 // set state and send pairing response 3337 sm_timeout_start(connection); 3338 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3339 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3340 break; 3341 case SM_BR_EDR_DISTRIBUTE_KEYS: 3342 // send next key 3343 if (setup->sm_key_distribution_send_set != 0) { 3344 sm_run_distribute_keys(connection); 3345 } 3346 3347 // more to send? 3348 if (setup->sm_key_distribution_send_set != 0){ 3349 return; 3350 } 3351 3352 // keys are sent 3353 if (IS_RESPONDER(connection->sm_role)) { 3354 // responder -> receive master keys if there are any 3355 if (!sm_key_distribution_all_received()){ 3356 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3357 break; 3358 } 3359 } 3360 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3361 sm_ctkd_start_from_br_edr(connection); 3362 continue; 3363 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3364 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3365 h6_calculate_ilk_from_le_ltk(connection); 3366 break; 3367 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3368 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3369 h6_calculate_br_edr_link_key(connection); 3370 break; 3371 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3372 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3373 h7_calculate_ilk_from_le_ltk(connection); 3374 break; 3375 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3376 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3377 h6_calculate_ilk_from_br_edr(connection); 3378 break; 3379 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3380 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3381 h6_calculate_le_ltk(connection); 3382 break; 3383 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3384 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3385 h7_calculate_ilk_from_br_edr(connection); 3386 break; 3387 #endif 3388 3389 default: 3390 break; 3391 } 3392 3393 // check again if active connection was released 3394 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3395 } 3396 } 3397 3398 // sm_aes128_state stays active 3399 static void sm_handle_encryption_result_enc_a(void *arg){ 3400 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3401 sm_aes128_state = SM_AES128_IDLE; 3402 3403 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3404 if (connection == NULL) return; 3405 3406 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3407 sm_aes128_state = SM_AES128_ACTIVE; 3408 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); 3409 } 3410 3411 static void sm_handle_encryption_result_enc_b(void *arg){ 3412 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3413 sm_aes128_state = SM_AES128_IDLE; 3414 3415 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3416 if (connection == NULL) return; 3417 3418 log_info_key("c1!", setup->sm_local_confirm); 3419 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3420 sm_trigger_run(); 3421 } 3422 3423 // sm_aes128_state stays active 3424 static void sm_handle_encryption_result_enc_c(void *arg){ 3425 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3426 sm_aes128_state = SM_AES128_IDLE; 3427 3428 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3429 if (connection == NULL) return; 3430 3431 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3432 sm_aes128_state = SM_AES128_ACTIVE; 3433 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); 3434 } 3435 3436 static void sm_handle_encryption_result_enc_d(void * arg){ 3437 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3438 sm_aes128_state = SM_AES128_IDLE; 3439 3440 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3441 if (connection == NULL) return; 3442 3443 log_info_key("c1!", sm_aes128_ciphertext); 3444 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3445 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3446 sm_trigger_run(); 3447 return; 3448 } 3449 if (IS_RESPONDER(connection->sm_role)){ 3450 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3451 sm_trigger_run(); 3452 } else { 3453 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3454 sm_aes128_state = SM_AES128_ACTIVE; 3455 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); 3456 } 3457 } 3458 3459 static void sm_handle_encryption_result_enc_stk(void *arg){ 3460 sm_aes128_state = SM_AES128_IDLE; 3461 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3462 3463 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3464 if (connection == NULL) return; 3465 3466 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3467 log_info_key("stk", setup->sm_ltk); 3468 if (IS_RESPONDER(connection->sm_role)){ 3469 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3470 } else { 3471 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3472 } 3473 sm_trigger_run(); 3474 } 3475 3476 // sm_aes128_state stays active 3477 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3478 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3479 sm_aes128_state = SM_AES128_IDLE; 3480 3481 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3482 if (connection == NULL) return; 3483 3484 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3485 log_info_hex16("y", setup->sm_local_y); 3486 // PH3B3 - calculate EDIV 3487 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3488 log_info_hex16("ediv", setup->sm_local_ediv); 3489 // PH3B4 - calculate LTK - enc 3490 // LTK = d1(ER, DIV, 0)) 3491 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3492 sm_aes128_state = SM_AES128_ACTIVE; 3493 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); 3494 } 3495 3496 #ifdef ENABLE_LE_PERIPHERAL 3497 // sm_aes128_state stays active 3498 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3499 sm_aes128_state = SM_AES128_IDLE; 3500 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3501 3502 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3503 if (connection == NULL) return; 3504 3505 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3506 log_info_hex16("y", setup->sm_local_y); 3507 3508 // PH3B3 - calculate DIV 3509 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3510 log_info_hex16("ediv", setup->sm_local_ediv); 3511 // PH3B4 - calculate LTK - enc 3512 // LTK = d1(ER, DIV, 0)) 3513 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3514 sm_aes128_state = SM_AES128_ACTIVE; 3515 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); 3516 } 3517 #endif 3518 3519 // sm_aes128_state stays active 3520 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3521 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3522 sm_aes128_state = SM_AES128_IDLE; 3523 3524 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3525 if (connection == NULL) return; 3526 3527 log_info_key("ltk", setup->sm_ltk); 3528 // calc CSRK next 3529 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3530 sm_aes128_state = SM_AES128_ACTIVE; 3531 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); 3532 } 3533 3534 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3535 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3536 sm_aes128_state = SM_AES128_IDLE; 3537 3538 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3539 if (connection == NULL) return; 3540 3541 sm_aes128_state = SM_AES128_IDLE; 3542 log_info_key("csrk", setup->sm_local_csrk); 3543 if (setup->sm_key_distribution_send_set != 0u){ 3544 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3545 } else { 3546 // no keys to send, just continue 3547 if (IS_RESPONDER(connection->sm_role)){ 3548 if (sm_key_distribution_all_received()){ 3549 sm_key_distribution_handle_all_received(connection); 3550 sm_key_distribution_complete_responder(connection); 3551 } else { 3552 // slave -> receive master keys 3553 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3554 } 3555 } else { 3556 sm_key_distribution_complete_initiator(connection); 3557 } 3558 } 3559 sm_trigger_run(); 3560 } 3561 3562 #ifdef ENABLE_LE_PERIPHERAL 3563 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3564 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3565 sm_aes128_state = SM_AES128_IDLE; 3566 3567 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3568 if (connection == NULL) return; 3569 3570 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3571 log_info_key("ltk", setup->sm_ltk); 3572 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3573 sm_trigger_run(); 3574 } 3575 #endif 3576 3577 static void sm_handle_encryption_result_address_resolution(void *arg){ 3578 UNUSED(arg); 3579 sm_aes128_state = SM_AES128_IDLE; 3580 3581 // compare calulated address against connecting device 3582 uint8_t * hash = &sm_aes128_ciphertext[13]; 3583 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3584 log_info("LE Device Lookup: matched resolvable private address"); 3585 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3586 sm_trigger_run(); 3587 return; 3588 } 3589 // no match, try next 3590 sm_address_resolution_test++; 3591 sm_trigger_run(); 3592 } 3593 3594 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3595 UNUSED(arg); 3596 sm_aes128_state = SM_AES128_IDLE; 3597 3598 log_info_key("irk", sm_persistent_irk); 3599 dkg_state = DKG_CALC_DHK; 3600 sm_trigger_run(); 3601 } 3602 3603 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3604 UNUSED(arg); 3605 sm_aes128_state = SM_AES128_IDLE; 3606 3607 log_info_key("dhk", sm_persistent_dhk); 3608 dkg_state = DKG_READY; 3609 sm_trigger_run(); 3610 } 3611 3612 static void sm_handle_encryption_result_rau(void *arg){ 3613 UNUSED(arg); 3614 sm_aes128_state = SM_AES128_IDLE; 3615 3616 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3617 rau_state = RAU_IDLE; 3618 hci_le_random_address_set(sm_random_address); 3619 3620 sm_trigger_run(); 3621 } 3622 3623 static void sm_handle_random_result_rau(void * arg){ 3624 UNUSED(arg); 3625 // non-resolvable vs. resolvable 3626 switch (gap_random_adress_type){ 3627 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3628 // resolvable: use random as prand and calc address hash 3629 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3630 sm_random_address[0u] &= 0x3fu; 3631 sm_random_address[0u] |= 0x40u; 3632 rau_state = RAU_GET_ENC; 3633 break; 3634 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3635 default: 3636 // "The two most significant bits of the address shall be equal to ‘0’"" 3637 sm_random_address[0u] &= 0x3fu; 3638 rau_state = RAU_IDLE; 3639 hci_le_random_address_set(sm_random_address); 3640 break; 3641 } 3642 sm_trigger_run(); 3643 } 3644 3645 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3646 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3647 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3648 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3649 if (connection == NULL) return; 3650 3651 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3652 sm_trigger_run(); 3653 } 3654 3655 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3656 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3657 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3658 if (connection == NULL) return; 3659 3660 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3661 sm_trigger_run(); 3662 } 3663 #endif 3664 3665 static void sm_handle_random_result_ph2_random(void * arg){ 3666 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3667 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3668 if (connection == NULL) return; 3669 3670 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3671 sm_trigger_run(); 3672 } 3673 3674 static void sm_handle_random_result_ph2_tk(void * arg){ 3675 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3676 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3677 if (connection == NULL) return; 3678 3679 sm_reset_tk(); 3680 uint32_t tk; 3681 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3682 // map random to 0-999999 without speding much cycles on a modulus operation 3683 tk = little_endian_read_32(sm_random_data,0); 3684 tk = tk & 0xfffff; // 1048575 3685 if (tk >= 999999u){ 3686 tk = tk - 999999u; 3687 } 3688 } else { 3689 // override with pre-defined passkey 3690 tk = sm_fixed_passkey_in_display_role; 3691 } 3692 big_endian_store_32(setup->sm_tk, 12, tk); 3693 if (IS_RESPONDER(connection->sm_role)){ 3694 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3695 } else { 3696 if (setup->sm_use_secure_connections){ 3697 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3698 } else { 3699 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3700 sm_trigger_user_response(connection); 3701 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3702 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3703 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); 3704 } 3705 } 3706 } 3707 sm_trigger_run(); 3708 } 3709 3710 static void sm_handle_random_result_ph3_div(void * arg){ 3711 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3712 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3713 if (connection == NULL) return; 3714 3715 // use 16 bit from random value as div 3716 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3717 log_info_hex16("div", setup->sm_local_div); 3718 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3719 sm_trigger_run(); 3720 } 3721 3722 static void sm_handle_random_result_ph3_random(void * arg){ 3723 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3724 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3725 if (connection == NULL) return; 3726 3727 reverse_64(sm_random_data, setup->sm_local_rand); 3728 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3729 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3730 // no db for authenticated flag hack: store flag in bit 4 of LSB 3731 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3732 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3733 } 3734 static void sm_validate_er_ir(void){ 3735 // warn about default ER/IR 3736 bool warning = false; 3737 if (sm_ir_is_default()){ 3738 warning = true; 3739 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3740 } 3741 if (sm_er_is_default()){ 3742 warning = true; 3743 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3744 } 3745 if (warning) { 3746 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3747 } 3748 } 3749 3750 static void sm_handle_random_result_ir(void *arg){ 3751 sm_persistent_keys_random_active = false; 3752 if (arg != NULL){ 3753 // key generated, store in tlv 3754 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3755 log_info("Generated IR key. Store in TLV status: %d", status); 3756 UNUSED(status); 3757 } 3758 log_info_key("IR", sm_persistent_ir); 3759 dkg_state = DKG_CALC_IRK; 3760 3761 if (test_use_fixed_local_irk){ 3762 log_info_key("IRK", sm_persistent_irk); 3763 dkg_state = DKG_CALC_DHK; 3764 } 3765 3766 sm_trigger_run(); 3767 } 3768 3769 static void sm_handle_random_result_er(void *arg){ 3770 sm_persistent_keys_random_active = false; 3771 if (arg != NULL){ 3772 // key generated, store in tlv 3773 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3774 log_info("Generated ER key. Store in TLV status: %d", status); 3775 UNUSED(status); 3776 } 3777 log_info_key("ER", sm_persistent_er); 3778 3779 // try load ir 3780 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3781 if (key_size == 16){ 3782 // ok, let's continue 3783 log_info("IR from TLV"); 3784 sm_handle_random_result_ir( NULL ); 3785 } else { 3786 // invalid, generate new random one 3787 sm_persistent_keys_random_active = true; 3788 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3789 } 3790 } 3791 3792 static void sm_connection_init(sm_connection_t * sm_conn, hci_con_handle_t con_handle, uint8_t role, uint8_t peer_addr_type, bd_addr_t peer_address){ 3793 3794 // connection info 3795 sm_conn->sm_handle = con_handle; 3796 sm_conn->sm_role = role; 3797 sm_conn->sm_peer_addr_type = peer_addr_type; 3798 memcpy(sm_conn->sm_peer_address, peer_address, 6); 3799 3800 // security properties 3801 sm_conn->sm_connection_encrypted = 0; 3802 sm_conn->sm_connection_authenticated = 0; 3803 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3804 sm_conn->sm_le_db_index = -1; 3805 sm_conn->sm_reencryption_active = false; 3806 3807 // prepare CSRK lookup (does not involve setup) 3808 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3809 3810 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3811 } 3812 3813 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3814 static void sm_event_handle_classic_encryption_event(sm_connection_t * sm_conn, hci_con_handle_t con_handle){ 3815 // CTKD requires BR/EDR Secure Connection 3816 if (sm_conn->sm_connection_encrypted != 2) return; 3817 // prepare for pairing request 3818 if (IS_RESPONDER(sm_conn->sm_role)){ 3819 log_info("CTKD: SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST"); 3820 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3821 } else if (sm_conn->sm_pairing_requested){ 3822 // check if remote supports fixed channels 3823 bool defer = true; 3824 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 3825 if (hci_connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE){ 3826 // check if remote supports SMP over BR/EDR 3827 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 3828 log_info("CTKD: SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST"); 3829 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3830 } else { 3831 defer = false; 3832 } 3833 } else { 3834 // wait for fixed channel info 3835 log_info("CTKD: SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK"); 3836 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK; 3837 } 3838 if (defer){ 3839 hci_dedicated_bonding_defer_disconnect(con_handle, true); 3840 } 3841 } 3842 } 3843 #endif 3844 3845 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3846 3847 UNUSED(channel); // ok: there is no channel 3848 UNUSED(size); // ok: fixed format HCI events 3849 3850 sm_connection_t * sm_conn; 3851 hci_con_handle_t con_handle; 3852 uint8_t status; 3853 bd_addr_t addr; 3854 bd_addr_type_t addr_type; 3855 3856 switch (packet_type) { 3857 3858 case HCI_EVENT_PACKET: 3859 switch (hci_event_packet_get_type(packet)) { 3860 3861 case BTSTACK_EVENT_STATE: 3862 switch (btstack_event_state_get_state(packet)){ 3863 case HCI_STATE_WORKING: 3864 log_info("HCI Working!"); 3865 // setup IR/ER with TLV 3866 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3867 if (sm_tlv_impl != NULL){ 3868 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3869 if (key_size == 16){ 3870 // ok, let's continue 3871 log_info("ER from TLV"); 3872 sm_handle_random_result_er( NULL ); 3873 } else { 3874 // invalid, generate random one 3875 sm_persistent_keys_random_active = true; 3876 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3877 } 3878 } else { 3879 sm_validate_er_ir(); 3880 dkg_state = DKG_CALC_IRK; 3881 3882 if (test_use_fixed_local_irk){ 3883 log_info_key("IRK", sm_persistent_irk); 3884 dkg_state = DKG_CALC_DHK; 3885 } 3886 } 3887 3888 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3889 // trigger ECC key generation 3890 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3891 sm_ec_generate_new_key(); 3892 } 3893 #endif 3894 3895 // restart random address updates after power cycle 3896 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ 3897 gap_random_address_set(sm_random_address); 3898 } else { 3899 gap_random_address_set_mode(gap_random_adress_type); 3900 } 3901 break; 3902 3903 case HCI_STATE_OFF: 3904 case HCI_STATE_HALTING: 3905 log_info("SM: reset state"); 3906 // stop random address update 3907 gap_random_address_update_stop(); 3908 // reset state 3909 sm_state_reset(); 3910 break; 3911 3912 default: 3913 break; 3914 } 3915 break; 3916 3917 #ifdef ENABLE_CLASSIC 3918 case HCI_EVENT_CONNECTION_COMPLETE: 3919 // ignore if connection failed 3920 if (hci_event_connection_complete_get_status(packet)) return; 3921 3922 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3923 sm_conn = sm_get_connection_for_handle(con_handle); 3924 if (!sm_conn) break; 3925 3926 hci_event_connection_complete_get_bd_addr(packet, addr); 3927 sm_connection_init(sm_conn, 3928 con_handle, 3929 (uint8_t) gap_get_role(con_handle), 3930 BD_ADDR_TYPE_LE_PUBLIC, 3931 addr); 3932 // classic connection corresponds to public le address 3933 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3934 gap_local_bd_addr(sm_conn->sm_own_address); 3935 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3936 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3937 break; 3938 3939 #endif 3940 3941 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3942 case HCI_EVENT_ROLE_CHANGE: 3943 hci_event_role_change_get_bd_addr(packet, addr); 3944 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3945 if (sm_conn == NULL) break; 3946 sm_conn->sm_role = hci_event_role_change_get_role(packet); 3947 break; 3948 3949 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3950 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3951 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3952 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3953 if (sm_conn == NULL) break; 3954 sm_conn->sm_pairing_requested = true; 3955 break; 3956 #endif 3957 3958 case HCI_EVENT_META_GAP: 3959 switch (hci_event_gap_meta_get_subevent_code(packet)) { 3960 case GAP_SUBEVENT_LE_CONNECTION_COMPLETE: 3961 // ignore if connection failed 3962 if (gap_subevent_le_connection_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3963 3964 con_handle = gap_subevent_le_connection_complete_get_connection_handle(packet); 3965 sm_conn = sm_get_connection_for_handle(con_handle); 3966 if (!sm_conn) break; 3967 3968 // Get current peer address 3969 addr_type = gap_subevent_le_connection_complete_get_peer_address_type(packet); 3970 if (hci_is_le_identity_address_type(addr_type)){ 3971 addr_type = BD_ADDR_TYPE_LE_RANDOM; 3972 gap_subevent_le_connection_complete_get_peer_resolvable_private_address(packet, addr); 3973 } else { 3974 gap_subevent_le_connection_complete_get_peer_address(packet, addr); 3975 } 3976 sm_connection_init(sm_conn, 3977 con_handle, 3978 gap_subevent_le_connection_complete_get_role(packet), 3979 addr_type, 3980 addr); 3981 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3982 3983 // track our addr used for this connection and set state 3984 #ifdef ENABLE_LE_PERIPHERAL 3985 if (gap_subevent_le_connection_complete_get_role(packet) != 0){ 3986 // responder - use own address from advertisements 3987 #ifdef ENABLE_LE_EXTENDED_ADVERTISING 3988 if (hci_le_extended_advertising_supported()){ 3989 // cache local resolvable address 3990 // note: will be overwritten if random or private address was used in adv set by HCI_SUBEVENT_LE_ADVERTISING_SET_TERMINATED 3991 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_RANDOM; 3992 gap_subevent_le_connection_complete_get_local_resolvable_private_address(packet,sm_conn->sm_own_address); 3993 } else 3994 #endif 3995 { 3996 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3997 } 3998 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3999 } 4000 #endif 4001 #ifdef ENABLE_LE_CENTRAL 4002 if (gap_subevent_le_connection_complete_get_role(packet) == 0){ 4003 // initiator - use own address from create connection 4004 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 4005 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4006 } 4007 #endif 4008 break; 4009 default: 4010 break; 4011 } 4012 break; 4013 case HCI_EVENT_LE_META: 4014 switch (hci_event_le_meta_get_subevent_code(packet)) { 4015 #ifdef ENABLE_LE_PERIPHERAL 4016 #ifdef ENABLE_LE_EXTENDED_ADVERTISING 4017 case HCI_SUBEVENT_LE_ADVERTISING_SET_TERMINATED: 4018 if (hci_subevent_le_advertising_set_terminated_get_status(packet) == ERROR_CODE_SUCCESS){ 4019 uint8_t advertising_handle = hci_subevent_le_advertising_set_terminated_get_advertising_handle(packet); 4020 con_handle = hci_subevent_le_advertising_set_terminated_get_connection_handle(packet); 4021 sm_conn = sm_get_connection_for_handle(con_handle); 4022 if (!sm_conn) break; 4023 4024 gap_le_get_own_advertising_set_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address, advertising_handle); 4025 log_info("Adv set %u terminated -> use addr type %u, addr %s for con handle 0x%04x", advertising_handle, sm_conn->sm_own_addr_type, 4026 bd_addr_to_str(sm_conn->sm_own_address), con_handle); 4027 } 4028 break; 4029 #endif 4030 #endif 4031 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 4032 con_handle = hci_subevent_le_long_term_key_request_get_connection_handle(packet); 4033 sm_conn = sm_get_connection_for_handle(con_handle); 4034 if (!sm_conn) break; 4035 4036 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 4037 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 4038 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 4039 break; 4040 } 4041 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 4042 // PH2 SEND LTK as we need to exchange keys in PH3 4043 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 4044 break; 4045 } 4046 4047 // store rand and ediv 4048 reverse_64(&packet[5], sm_conn->sm_local_rand); 4049 sm_conn->sm_local_ediv = hci_subevent_le_long_term_key_request_get_encryption_diversifier(packet); 4050 4051 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 4052 // potentially stored LTK is from the master 4053 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 4054 if (sm_reconstruct_ltk_without_le_device_db_entry){ 4055 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 4056 break; 4057 } 4058 // additionally check if remote is in LE Device DB if requested 4059 switch(sm_conn->sm_irk_lookup_state){ 4060 case IRK_LOOKUP_FAILED: 4061 log_info("LTK Request: device not in device db"); 4062 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 4063 break; 4064 case IRK_LOOKUP_SUCCEEDED: 4065 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 4066 break; 4067 default: 4068 // wait for irk look doen 4069 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 4070 break; 4071 } 4072 break; 4073 } 4074 4075 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4076 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 4077 #else 4078 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 4079 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 4080 #endif 4081 break; 4082 4083 default: 4084 break; 4085 } 4086 break; 4087 4088 case HCI_EVENT_ENCRYPTION_CHANGE: 4089 case HCI_EVENT_ENCRYPTION_CHANGE_V2: 4090 con_handle = hci_event_encryption_change_get_connection_handle(packet); 4091 sm_conn = sm_get_connection_for_handle(con_handle); 4092 if (!sm_conn) break; 4093 4094 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 4095 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 4096 sm_conn->sm_actual_encryption_key_size); 4097 log_info("event handler, state %u", sm_conn->sm_engine_state); 4098 4099 switch (sm_conn->sm_engine_state){ 4100 4101 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4102 // encryption change event concludes re-encryption for bonded devices (even if it fails) 4103 if (sm_conn->sm_connection_encrypted != 0u) { 4104 status = ERROR_CODE_SUCCESS; 4105 if (IS_RESPONDER(sm_conn->sm_role)){ 4106 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4107 } else { 4108 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4109 } 4110 } else { 4111 status = hci_event_encryption_change_get_status(packet); 4112 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 4113 // also, gap_reconnect_security_setup_active will return true 4114 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 4115 } 4116 4117 // emit re-encryption complete 4118 sm_reencryption_complete(sm_conn, status); 4119 4120 // notify client, if pairing was requested before 4121 if (sm_conn->sm_pairing_requested){ 4122 sm_conn->sm_pairing_requested = false; 4123 sm_pairing_complete(sm_conn, status, 0); 4124 } 4125 4126 sm_done_for_handle(sm_conn->sm_handle); 4127 break; 4128 4129 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4130 if (!sm_conn->sm_connection_encrypted) break; 4131 // handler for HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE 4132 // contains the same code for this state 4133 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 4134 if (IS_RESPONDER(sm_conn->sm_role)){ 4135 // slave 4136 if (sm_conn->sm_connection_sc){ 4137 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4138 } else { 4139 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); 4140 } 4141 } else { 4142 // master 4143 if (sm_key_distribution_all_received()){ 4144 // skip receiving keys as there are none 4145 sm_key_distribution_handle_all_received(sm_conn); 4146 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); 4147 } else { 4148 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4149 } 4150 } 4151 break; 4152 4153 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4154 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4155 sm_event_handle_classic_encryption_event(sm_conn, con_handle); 4156 break; 4157 #endif 4158 default: 4159 break; 4160 } 4161 break; 4162 4163 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 4164 con_handle = little_endian_read_16(packet, 3); 4165 sm_conn = sm_get_connection_for_handle(con_handle); 4166 if (!sm_conn) break; 4167 4168 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 4169 log_info("event handler, state %u", sm_conn->sm_engine_state); 4170 // continue if part of initial pairing 4171 switch (sm_conn->sm_engine_state){ 4172 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4173 if (IS_RESPONDER(sm_conn->sm_role)){ 4174 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4175 } else { 4176 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4177 } 4178 sm_done_for_handle(sm_conn->sm_handle); 4179 break; 4180 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4181 // handler for HCI_EVENT_ENCRYPTION_CHANGE 4182 // contains the same code for this state 4183 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 4184 if (IS_RESPONDER(sm_conn->sm_role)){ 4185 // slave 4186 if (sm_conn->sm_connection_sc){ 4187 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4188 } else { 4189 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); 4190 } 4191 } else { 4192 // master 4193 if (sm_key_distribution_all_received()){ 4194 // skip receiving keys as there are none 4195 sm_key_distribution_handle_all_received(sm_conn); 4196 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); 4197 } else { 4198 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4199 } 4200 } 4201 break; 4202 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4203 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4204 sm_event_handle_classic_encryption_event(sm_conn, con_handle); 4205 break; 4206 #endif 4207 default: 4208 break; 4209 } 4210 break; 4211 4212 4213 case HCI_EVENT_DISCONNECTION_COMPLETE: 4214 con_handle = little_endian_read_16(packet, 3); 4215 sm_done_for_handle(con_handle); 4216 sm_conn = sm_get_connection_for_handle(con_handle); 4217 if (!sm_conn) break; 4218 4219 // pairing failed, if it was ongoing 4220 switch (sm_conn->sm_engine_state){ 4221 case SM_GENERAL_IDLE: 4222 case SM_INITIATOR_CONNECTED: 4223 case SM_RESPONDER_IDLE: 4224 break; 4225 default: 4226 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 4227 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 4228 break; 4229 } 4230 4231 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 4232 sm_conn->sm_handle = 0; 4233 break; 4234 4235 case HCI_EVENT_COMMAND_COMPLETE: 4236 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 4237 // set local addr for le device db 4238 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 4239 le_device_db_set_local_bd_addr(addr); 4240 } 4241 break; 4242 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4243 case L2CAP_EVENT_INFORMATION_RESPONSE: 4244 con_handle = l2cap_event_information_response_get_con_handle(packet); 4245 sm_conn = sm_get_connection_for_handle(con_handle); 4246 if (!sm_conn) break; 4247 if (sm_conn->sm_engine_state == SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK){ 4248 // check if remote supports SMP over BR/EDR 4249 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 4250 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 4251 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 4252 } else { 4253 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4254 hci_dedicated_bonding_defer_disconnect(con_handle, false); 4255 } 4256 } 4257 break; 4258 #endif 4259 default: 4260 break; 4261 } 4262 break; 4263 default: 4264 break; 4265 } 4266 4267 sm_run(); 4268 } 4269 4270 static inline int sm_calc_actual_encryption_key_size(int other){ 4271 if (other < sm_min_encryption_key_size) return 0; 4272 if (other < sm_max_encryption_key_size) return other; 4273 return sm_max_encryption_key_size; 4274 } 4275 4276 4277 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4278 static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 4279 switch (method){ 4280 case JUST_WORKS: 4281 case NUMERIC_COMPARISON: 4282 return true; 4283 default: 4284 return false; 4285 } 4286 } 4287 // responder 4288 4289 static bool sm_passkey_used(stk_generation_method_t method){ 4290 switch (method){ 4291 case PK_RESP_INPUT: 4292 return true; 4293 default: 4294 return 0; 4295 } 4296 } 4297 4298 static bool sm_passkey_entry(stk_generation_method_t method){ 4299 switch (method){ 4300 case PK_RESP_INPUT: 4301 case PK_INIT_INPUT: 4302 case PK_BOTH_INPUT: 4303 return true; 4304 default: 4305 return false; 4306 } 4307 } 4308 4309 #endif 4310 4311 /** 4312 * @return ok 4313 */ 4314 static int sm_validate_stk_generation_method(void){ 4315 // check if STK generation method is acceptable by client 4316 switch (setup->sm_stk_generation_method){ 4317 case JUST_WORKS: 4318 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4319 case PK_RESP_INPUT: 4320 case PK_INIT_INPUT: 4321 case PK_BOTH_INPUT: 4322 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4323 case OOB: 4324 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4325 case NUMERIC_COMPARISON: 4326 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4327 default: 4328 return 0; 4329 } 4330 } 4331 4332 #ifdef ENABLE_LE_CENTRAL 4333 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4335 if (sm_sc_only_mode){ 4336 uint8_t auth_req = packet[1]; 4337 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4338 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4339 return; 4340 } 4341 } 4342 #else 4343 UNUSED(packet); 4344 #endif 4345 4346 int have_ltk; 4347 uint8_t ltk[16]; 4348 4349 // IRK complete? 4350 switch (sm_conn->sm_irk_lookup_state){ 4351 case IRK_LOOKUP_FAILED: 4352 // start pairing 4353 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4354 break; 4355 case IRK_LOOKUP_SUCCEEDED: 4356 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4357 have_ltk = !sm_is_null_key(ltk); 4358 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4359 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4360 // start re-encrypt if we have LTK and the connection is not already encrypted 4361 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4362 } else { 4363 // start pairing 4364 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4365 } 4366 break; 4367 default: 4368 // otherwise, store security request 4369 sm_conn->sm_security_request_received = true; 4370 break; 4371 } 4372 } 4373 #endif 4374 4375 static uint8_t sm_pdu_validate_and_get_opcode(uint8_t packet_type, const uint8_t *packet, uint16_t size){ 4376 4377 // size of complete sm_pdu used to validate input 4378 static const uint8_t sm_pdu_size[] = { 4379 0, // 0x00 invalid opcode 4380 7, // 0x01 pairing request 4381 7, // 0x02 pairing response 4382 17, // 0x03 pairing confirm 4383 17, // 0x04 pairing random 4384 2, // 0x05 pairing failed 4385 17, // 0x06 encryption information 4386 11, // 0x07 master identification 4387 17, // 0x08 identification information 4388 8, // 0x09 identify address information 4389 17, // 0x0a signing information 4390 2, // 0x0b security request 4391 65, // 0x0c pairing public key 4392 17, // 0x0d pairing dhk check 4393 2, // 0x0e keypress notification 4394 }; 4395 4396 if (packet_type != SM_DATA_PACKET) return 0; 4397 if (size == 0u) return 0; 4398 4399 uint8_t sm_pdu_code = packet[0]; 4400 4401 // validate pdu size 4402 if (sm_pdu_code >= sizeof(sm_pdu_size)) return 0; 4403 if (sm_pdu_size[sm_pdu_code] != size) return 0; 4404 4405 return sm_pdu_code; 4406 } 4407 4408 4409 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4410 static void sm_pdu_handler_pairing_public_key(sm_connection_t * sm_conn, const uint8_t * packet) { 4411 // store public key for DH Key calculation 4412 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4413 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4414 4415 // CVE-2020-26558: abort pairing if remote uses the same public key 4416 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4417 log_info("Remote PK matches ours"); 4418 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4419 return; 4420 } 4421 4422 // validate public key 4423 int err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4424 if (err != 0){ 4425 log_info("sm: peer public key invalid %x", err); 4426 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4427 return; 4428 } 4429 4430 // start calculating dhkey 4431 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); 4432 4433 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4434 if (IS_RESPONDER(sm_conn->sm_role)){ 4435 // responder 4436 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4437 } else { 4438 // initiator 4439 // stk generation method 4440 // passkey entry: notify app to show passkey or to request passkey 4441 switch (setup->sm_stk_generation_method){ 4442 case JUST_WORKS: 4443 case NUMERIC_COMPARISON: 4444 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4445 break; 4446 case PK_RESP_INPUT: 4447 sm_sc_start_calculating_local_confirm(sm_conn); 4448 break; 4449 case PK_INIT_INPUT: 4450 case PK_BOTH_INPUT: 4451 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4452 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4453 break; 4454 } 4455 sm_sc_start_calculating_local_confirm(sm_conn); 4456 break; 4457 case OOB: 4458 if (setup->sm_have_oob_data){ 4459 // if we have received rb & cb, verify Cb = f4(PKb, PKb, rb, 0) 4460 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4461 } else { 4462 // otherwise, generate our nonce 4463 sm_sc_generate_nx_for_send_random(sm_conn); 4464 } 4465 break; 4466 default: 4467 btstack_assert(false); 4468 break; 4469 } 4470 } 4471 } 4472 #endif 4473 4474 4475 static void sm_pdu_handler(sm_connection_t *sm_conn, uint8_t sm_pdu_code, const uint8_t *packet) { 4476 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4477 4478 #ifdef ENABLE_LE_CENTRAL 4479 int err; 4480 #endif 4481 uint8_t max_encryption_key_size; 4482 4483 switch (sm_conn->sm_engine_state){ 4484 4485 // a sm timeout requires a new physical connection 4486 case SM_GENERAL_TIMEOUT: 4487 return; 4488 4489 #ifdef ENABLE_LE_CENTRAL 4490 4491 // Initiator 4492 case SM_INITIATOR_CONNECTED: 4493 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4494 sm_pdu_received_in_wrong_state(sm_conn); 4495 break; 4496 } 4497 sm_initiator_connected_handle_security_request(sm_conn, packet); 4498 break; 4499 4500 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4501 // Core 5, Vol 3, Part H, 2.4.6: 4502 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4503 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4504 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4505 log_info("Ignoring Security Request"); 4506 break; 4507 } 4508 4509 // all other pdus are incorrect 4510 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4511 sm_pdu_received_in_wrong_state(sm_conn); 4512 break; 4513 } 4514 4515 // store pairing request 4516 (void)memcpy(&setup->sm_s_pres, packet, 4517 sizeof(sm_pairing_packet_t)); 4518 4519 // validate encryption key size 4520 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); 4521 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4522 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4523 break; 4524 } 4525 4526 err = sm_stk_generation_init(sm_conn); 4527 4528 #ifdef ENABLE_TESTING_SUPPORT 4529 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4530 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4531 err = test_pairing_failure; 4532 } 4533 #endif 4534 4535 if (err != 0){ 4536 sm_pairing_error(sm_conn, err); 4537 break; 4538 } 4539 4540 // generate random number first, if we need to show passkey 4541 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4542 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); 4543 break; 4544 } 4545 4546 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4547 if (setup->sm_use_secure_connections){ 4548 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4549 if (setup->sm_stk_generation_method == JUST_WORKS){ 4550 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4551 sm_trigger_user_response(sm_conn); 4552 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4553 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4554 } 4555 } else { 4556 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4557 } 4558 break; 4559 } 4560 #endif 4561 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4562 sm_trigger_user_response(sm_conn); 4563 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4564 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4565 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); 4566 } 4567 break; 4568 4569 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4570 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4571 sm_pdu_received_in_wrong_state(sm_conn); 4572 break; 4573 } 4574 4575 // store s_confirm 4576 reverse_128(&packet[1], setup->sm_peer_confirm); 4577 4578 // abort if s_confirm matches m_confirm 4579 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4580 sm_pdu_received_in_wrong_state(sm_conn); 4581 break; 4582 } 4583 4584 #ifdef ENABLE_TESTING_SUPPORT 4585 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4586 log_info("testing_support: reset confirm value"); 4587 memset(setup->sm_peer_confirm, 0, 16); 4588 } 4589 #endif 4590 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4591 break; 4592 4593 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4594 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4595 sm_pdu_received_in_wrong_state(sm_conn); 4596 break;; 4597 } 4598 4599 // received random value 4600 reverse_128(&packet[1], setup->sm_peer_random); 4601 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4602 break; 4603 4604 case SM_INITIATOR_PH4_HAS_LTK: 4605 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4606 // ignore Security Request, see SM_INITIATOR_PH1_W4_PAIRING_RESPONSE above 4607 if (sm_pdu_code != SM_CODE_SECURITY_REQUEST){ 4608 sm_pdu_received_in_wrong_state(sm_conn); 4609 } 4610 break; 4611 #endif 4612 4613 #ifdef ENABLE_LE_PERIPHERAL 4614 // Responder 4615 case SM_RESPONDER_IDLE: 4616 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4617 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4618 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4619 sm_pdu_received_in_wrong_state(sm_conn); 4620 break;; 4621 } 4622 4623 // store pairing request 4624 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4625 4626 // validation encryption key size 4627 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); 4628 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4629 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4630 break; 4631 } 4632 4633 // check if IRK completed 4634 switch (sm_conn->sm_irk_lookup_state){ 4635 case IRK_LOOKUP_SUCCEEDED: 4636 case IRK_LOOKUP_FAILED: 4637 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4638 break; 4639 default: 4640 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4641 break; 4642 } 4643 break; 4644 #endif 4645 4646 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4647 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4648 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4649 sm_pdu_received_in_wrong_state(sm_conn); 4650 break; 4651 } 4652 sm_pdu_handler_pairing_public_key(sm_conn, packet); 4653 break; 4654 4655 case SM_SC_W4_CONFIRMATION: 4656 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4657 sm_pdu_received_in_wrong_state(sm_conn); 4658 break; 4659 } 4660 // received confirm value 4661 reverse_128(&packet[1], setup->sm_peer_confirm); 4662 4663 #ifdef ENABLE_TESTING_SUPPORT 4664 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4665 log_info("testing_support: reset confirm value"); 4666 memset(setup->sm_peer_confirm, 0, 16); 4667 } 4668 #endif 4669 if (IS_RESPONDER(sm_conn->sm_role)){ 4670 // responder 4671 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4672 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4673 // still waiting for passkey 4674 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4675 break; 4676 } 4677 } 4678 sm_sc_start_calculating_local_confirm(sm_conn); 4679 } else { 4680 // initiator 4681 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4682 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); 4683 } else { 4684 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4685 } 4686 } 4687 break; 4688 4689 case SM_SC_W4_PAIRING_RANDOM: 4690 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4691 sm_pdu_received_in_wrong_state(sm_conn); 4692 break; 4693 } 4694 4695 // received random value 4696 reverse_128(&packet[1], setup->sm_peer_nonce); 4697 4698 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4699 // only check for JUST WORK/NC in initiator role OR passkey entry 4700 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4701 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4702 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4703 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4704 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4705 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4706 break; 4707 } 4708 4709 // OOB 4710 if (setup->sm_stk_generation_method == OOB){ 4711 4712 // setup local random, set to zero if remote did not receive our data 4713 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4714 if (IS_RESPONDER(sm_conn->sm_role)) { 4715 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u) { 4716 log_info("Reset rb as A does not have OOB data"); 4717 memset(setup->sm_rb, 0, 16); 4718 } else { 4719 (void) memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4720 log_info("Use stored rb"); 4721 log_info_hexdump(setup->sm_rb, 16); 4722 } 4723 } else { 4724 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4725 log_info("Reset ra as B does not have OOB data"); 4726 memset(setup->sm_ra, 0, 16); 4727 } else { 4728 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4729 log_info("Use stored ra"); 4730 log_info_hexdump(setup->sm_ra, 16); 4731 } 4732 } 4733 4734 if (IS_RESPONDER(sm_conn->sm_role)){ 4735 if (setup->sm_have_oob_data){ 4736 // if we have received ra & ca, verify Ca = f4(PKa, PKa, ra, 0) 4737 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4738 } else { 4739 // otherwise, generate our nonce 4740 sm_sc_generate_nx_for_send_random(sm_conn); 4741 } 4742 } else { 4743 // Confirm value already validated if received before, 4744 // move on to DHKey check 4745 sm_sc_prepare_dhkey_check(sm_conn); 4746 } 4747 break; 4748 } 4749 4750 // TODO: we only get here for Responder role with JW/NC 4751 sm_sc_state_after_receiving_random(sm_conn); 4752 break; 4753 4754 case SM_SC_W2_CALCULATE_G2: 4755 case SM_SC_W4_CALCULATE_G2: 4756 case SM_SC_W4_CALCULATE_DHKEY: 4757 case SM_SC_W2_CALCULATE_F5_SALT: 4758 case SM_SC_W4_CALCULATE_F5_SALT: 4759 case SM_SC_W2_CALCULATE_F5_MACKEY: 4760 case SM_SC_W4_CALCULATE_F5_MACKEY: 4761 case SM_SC_W2_CALCULATE_F5_LTK: 4762 case SM_SC_W4_CALCULATE_F5_LTK: 4763 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4764 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4765 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4766 case SM_SC_W4_USER_RESPONSE: 4767 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4768 sm_pdu_received_in_wrong_state(sm_conn); 4769 break; 4770 } 4771 // store DHKey Check 4772 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4773 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4774 4775 // have we been only waiting for dhkey check command? 4776 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4777 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4778 } 4779 break; 4780 #endif 4781 4782 #ifdef ENABLE_LE_PERIPHERAL 4783 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4784 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4785 sm_pdu_received_in_wrong_state(sm_conn); 4786 break; 4787 } 4788 4789 // received confirm value 4790 reverse_128(&packet[1], setup->sm_peer_confirm); 4791 4792 #ifdef ENABLE_TESTING_SUPPORT 4793 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4794 log_info("testing_support: reset confirm value"); 4795 memset(setup->sm_peer_confirm, 0, 16); 4796 } 4797 #endif 4798 // notify client to hide shown passkey 4799 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4800 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4801 } 4802 4803 // handle user cancel pairing? 4804 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4805 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4806 break; 4807 } 4808 4809 // wait for user action? 4810 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4811 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4812 break; 4813 } 4814 4815 // calculate and send local_confirm 4816 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); 4817 break; 4818 4819 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4820 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4821 sm_pdu_received_in_wrong_state(sm_conn); 4822 break;; 4823 } 4824 4825 // received random value 4826 reverse_128(&packet[1], setup->sm_peer_random); 4827 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4828 break; 4829 #endif 4830 4831 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4832 case SM_PH3_RECEIVE_KEYS: 4833 switch(sm_pdu_code){ 4834 case SM_CODE_ENCRYPTION_INFORMATION: 4835 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4836 reverse_128(&packet[1], setup->sm_peer_ltk); 4837 break; 4838 4839 case SM_CODE_MASTER_IDENTIFICATION: 4840 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4841 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4842 reverse_64(&packet[3], setup->sm_peer_rand); 4843 break; 4844 4845 case SM_CODE_IDENTITY_INFORMATION: 4846 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4847 reverse_128(&packet[1], setup->sm_peer_irk); 4848 break; 4849 4850 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4851 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4852 setup->sm_peer_addr_type = packet[1]; 4853 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4854 break; 4855 4856 case SM_CODE_SIGNING_INFORMATION: 4857 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4858 reverse_128(&packet[1], setup->sm_peer_csrk); 4859 break; 4860 default: 4861 // Unexpected PDU 4862 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4863 break; 4864 } 4865 // done with key distribution? 4866 if (sm_key_distribution_all_received()){ 4867 4868 sm_key_distribution_handle_all_received(sm_conn); 4869 4870 if (IS_RESPONDER(sm_conn->sm_role)){ 4871 sm_key_distribution_complete_responder(sm_conn); 4872 } else { 4873 if (setup->sm_use_secure_connections){ 4874 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4875 } else { 4876 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); 4877 } 4878 } 4879 } 4880 break; 4881 4882 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4883 4884 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4885 // GAP/DM/LEP/BI-02-C - reject CTKD if P-192 encryption is used 4886 if (sm_pdu_code == SM_CODE_PAIRING_REQUEST){ 4887 sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); 4888 } 4889 break; 4890 4891 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4892 4893 // dedicated bonding complete 4894 hci_dedicated_bonding_defer_disconnect(sm_conn->sm_handle, false); 4895 4896 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4897 sm_pdu_received_in_wrong_state(sm_conn); 4898 break; 4899 } 4900 // store pairing response 4901 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4902 4903 // validate encryption key size 4904 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); 4905 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4906 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4907 break; 4908 } 4909 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); 4910 // SC Only mandates 128 bit key size 4911 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4912 sm_conn->sm_actual_encryption_key_size = 0; 4913 } 4914 if (sm_conn->sm_actual_encryption_key_size == 0){ 4915 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4916 break; 4917 } 4918 4919 // prepare key exchange, LTK is derived locally 4920 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4921 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4922 4923 // skip receive if there are none 4924 if (sm_key_distribution_all_received()){ 4925 // distribute keys in run handles 'no keys to send' 4926 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4927 } else { 4928 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4929 } 4930 break; 4931 4932 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4933 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4934 sm_pdu_received_in_wrong_state(sm_conn); 4935 break; 4936 } 4937 4938 // store pairing request 4939 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4940 4941 // validate encryption key size 4942 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); 4943 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4944 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4945 break; 4946 } 4947 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); 4948 // SC Only mandates 128 bit key size 4949 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4950 sm_conn->sm_actual_encryption_key_size = 0; 4951 } 4952 if (sm_conn->sm_actual_encryption_key_size == 0){ 4953 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4954 break; 4955 } 4956 // trigger response 4957 if (sm_ctkd_from_classic(sm_conn)){ 4958 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4959 } else { 4960 sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); 4961 } 4962 break; 4963 4964 case SM_BR_EDR_RECEIVE_KEYS: 4965 switch(sm_pdu_code){ 4966 case SM_CODE_IDENTITY_INFORMATION: 4967 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4968 reverse_128(&packet[1], setup->sm_peer_irk); 4969 break; 4970 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4971 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4972 setup->sm_peer_addr_type = packet[1]; 4973 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4974 break; 4975 case SM_CODE_SIGNING_INFORMATION: 4976 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4977 reverse_128(&packet[1], setup->sm_peer_csrk); 4978 break; 4979 default: 4980 // Unexpected PDU 4981 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4982 break; 4983 } 4984 4985 // all keys received 4986 if (sm_key_distribution_all_received()){ 4987 if (IS_RESPONDER(sm_conn->sm_role)){ 4988 // responder -> keys exchanged, derive LE LTK 4989 sm_ctkd_start_from_br_edr(sm_conn); 4990 } else { 4991 // initiator -> send our keys if any 4992 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4993 } 4994 } 4995 break; 4996 #endif 4997 4998 default: 4999 // Unexpected PDU 5000 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 5001 sm_pdu_received_in_wrong_state(sm_conn); 5002 break; 5003 } 5004 5005 // try to send next pdu 5006 sm_trigger_run(); 5007 } 5008 5009 static void sm_channel_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 5010 5011 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 5012 sm_run(); 5013 } 5014 5015 uint8_t sm_pdu_code = sm_pdu_validate_and_get_opcode(packet_type, packet, size); 5016 if (sm_pdu_code == 0) return; 5017 5018 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5019 if (!sm_conn) return; 5020 5021 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 5022 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 5023 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 5024 sm_done_for_handle(con_handle); 5025 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 5026 return; 5027 } 5028 5029 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 5030 uint8_t buffer[5]; 5031 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 5032 buffer[1] = 3; 5033 little_endian_store_16(buffer, 2, con_handle); 5034 buffer[4] = packet[1]; 5035 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 5036 return; 5037 } 5038 5039 sm_pdu_handler(sm_conn, sm_pdu_code, packet); 5040 } 5041 5042 // Security Manager Client API 5043 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 5044 sm_get_oob_data = get_oob_data_callback; 5045 } 5046 5047 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)){ 5048 sm_get_sc_oob_data = get_sc_oob_data_callback; 5049 } 5050 5051 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)){ 5052 sm_get_ltk_callback = get_ltk_callback; 5053 } 5054 5055 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 5056 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 5057 } 5058 5059 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 5060 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 5061 } 5062 5063 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 5064 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 5065 } 5066 5067 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 5068 sm_min_encryption_key_size = min_size; 5069 sm_max_encryption_key_size = max_size; 5070 } 5071 5072 void sm_set_authentication_requirements(uint8_t auth_req){ 5073 #ifndef ENABLE_LE_SECURE_CONNECTIONS 5074 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 5075 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 5076 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 5077 } 5078 #endif 5079 sm_auth_req = auth_req; 5080 } 5081 5082 void sm_set_io_capabilities(io_capability_t io_capability){ 5083 sm_io_capabilities = io_capability; 5084 } 5085 5086 #ifdef ENABLE_LE_PERIPHERAL 5087 void sm_set_request_security(bool enable){ 5088 sm_slave_request_security = enable; 5089 } 5090 #endif 5091 5092 void sm_set_er(sm_key_t er){ 5093 (void)memcpy(sm_persistent_er, er, 16); 5094 } 5095 5096 void sm_set_ir(sm_key_t ir){ 5097 (void)memcpy(sm_persistent_ir, ir, 16); 5098 } 5099 5100 // Testing support only 5101 void sm_test_set_irk(sm_key_t irk){ 5102 (void)memcpy(sm_persistent_irk, irk, 16); 5103 dkg_state = DKG_CALC_DHK; 5104 test_use_fixed_local_irk = true; 5105 } 5106 5107 void sm_test_use_fixed_local_csrk(void){ 5108 test_use_fixed_local_csrk = true; 5109 } 5110 5111 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5112 static void sm_ec_generated(void * arg){ 5113 UNUSED(arg); 5114 ec_key_generation_state = EC_KEY_GENERATION_DONE; 5115 // trigger pairing if pending for ec key 5116 sm_trigger_run(); 5117 } 5118 static void sm_ec_generate_new_key(void) { 5119 log_info("sm: generate new ec key"); 5120 #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY 5121 // LE Secure Connections Debug Key 5122 const uint8_t debug_key_public[64] = { 5123 0x20, 0xb0, 0x03, 0xd2, 0xf2, 0x97, 0xbe, 0x2c, 0x5e, 0x2c, 0x83, 0xa7, 0xe9, 0xf9, 0xa5, 0xb9, 5124 0xef, 0xf4, 0x91, 0x11, 0xac, 0xf4, 0xfd, 0xdb, 0xcc, 0x03, 0x01, 0x48, 0x0e, 0x35, 0x9d, 0xe6, 5125 0xdc, 0x80, 0x9c, 0x49, 0x65, 0x2a, 0xeb, 0x6d, 0x63, 0x32, 0x9a, 0xbf, 0x5a, 0x52, 0x15, 0x5c, 5126 0x76, 0x63, 0x45, 0xc2, 0x8f, 0xed, 0x30, 0x24, 0x74, 0x1c, 0x8e, 0xd0, 0x15, 0x89, 0xd2, 0x8b 5127 }; 5128 const uint8_t debug_key_private[32] = { 5129 0x3f, 0x49, 0xf6, 0xd4, 0xa3, 0xc5, 0x5f, 0x38, 0x74, 0xc9, 0xb3, 0xe3, 0xd2, 0x10, 0x3f, 0x50, 5130 0x4a, 0xff, 0x60, 0x7b, 0xeb, 0x40, 0xb7, 0x99, 0x58, 0x99, 0xb8, 0xa6, 0xcd, 0x3c, 0x1a, 0xbd 5131 }; 5132 if (sm_sc_debug_keys_enabled) { 5133 memcpy(ec_q, debug_key_public, 64); 5134 btstack_crypto_ecc_p256_set_key(debug_key_public, debug_key_private); 5135 ec_key_generation_state = EC_KEY_GENERATION_DONE; 5136 } else 5137 #endif 5138 { 5139 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 5140 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 5141 } 5142 } 5143 #endif 5144 5145 #ifdef ENABLE_TESTING_SUPPORT 5146 void sm_test_set_pairing_failure(int reason){ 5147 test_pairing_failure = reason; 5148 } 5149 #endif 5150 5151 static void sm_state_reset(void) { 5152 #ifdef USE_CMAC_ENGINE 5153 sm_cmac_active = 0; 5154 #endif 5155 dkg_state = DKG_W4_WORKING; 5156 rau_state = RAU_IDLE; 5157 sm_aes128_state = SM_AES128_IDLE; 5158 sm_address_resolution_test = -1; // no private address to resolve yet 5159 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 5160 sm_address_resolution_general_queue = NULL; 5161 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 5162 sm_persistent_keys_random_active = false; 5163 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5164 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 5165 #endif 5166 } 5167 5168 void sm_init(void){ 5169 5170 if (sm_initialized) return; 5171 5172 // set default ER and IR values (should be unique - set by app or sm later using TLV) 5173 sm_er_ir_set_default(); 5174 5175 // defaults 5176 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 5177 | SM_STK_GENERATION_METHOD_OOB 5178 | SM_STK_GENERATION_METHOD_PASSKEY 5179 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 5180 5181 sm_max_encryption_key_size = 16; 5182 sm_min_encryption_key_size = 7; 5183 5184 sm_fixed_passkey_in_display_role = 0xffffffffU; 5185 sm_reconstruct_ltk_without_le_device_db_entry = true; 5186 5187 gap_random_adress_update_period = 15 * 60 * 1000L; 5188 5189 test_use_fixed_local_csrk = false; 5190 5191 // other 5192 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 5193 5194 // register for HCI Events 5195 hci_event_callback_registration.callback = &sm_event_packet_handler; 5196 hci_add_event_handler(&hci_event_callback_registration); 5197 5198 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 5199 // register for L2CAP events 5200 l2cap_event_callback_registration.callback = &sm_event_packet_handler; 5201 l2cap_add_event_handler(&l2cap_event_callback_registration); 5202 #endif 5203 5204 // 5205 btstack_crypto_init(); 5206 5207 // init le_device_db 5208 le_device_db_init(); 5209 5210 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 5211 l2cap_register_fixed_channel(sm_channel_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 5212 #ifdef ENABLE_CLASSIC 5213 l2cap_register_fixed_channel(sm_channel_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); 5214 #endif 5215 5216 // state 5217 sm_state_reset(); 5218 5219 sm_initialized = true; 5220 } 5221 5222 void sm_deinit(void){ 5223 sm_initialized = false; 5224 btstack_run_loop_remove_timer(&sm_run_timer); 5225 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) 5226 sm_sc_debug_keys_enabled = false; 5227 #endif 5228 } 5229 5230 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 5231 sm_fixed_passkey_in_display_role = passkey; 5232 } 5233 5234 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 5235 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 5236 } 5237 5238 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 5239 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 5240 if (!hci_con) return NULL; 5241 return &hci_con->sm_connection; 5242 } 5243 5244 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk){ 5245 hci_connection_t * hci_con = hci_connection_for_handle(connection->sm_handle); 5246 btstack_assert(hci_con != NULL); 5247 memcpy(hci_con->link_key, ltk, 16); 5248 hci_con->link_key_type = COMBINATION_KEY; 5249 } 5250 5251 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 5252 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 5253 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 5254 if (!hci_con) return NULL; 5255 return &hci_con->sm_connection; 5256 } 5257 #endif 5258 5259 // @deprecated: map onto sm_request_pairing 5260 void sm_send_security_request(hci_con_handle_t con_handle){ 5261 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5262 if (!sm_conn) return; 5263 if (!IS_RESPONDER(sm_conn->sm_role)) return; 5264 sm_request_pairing(con_handle); 5265 } 5266 5267 // request pairing 5268 void sm_request_pairing(hci_con_handle_t con_handle){ 5269 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5270 if (!sm_conn) return; // wrong connection 5271 5272 bool have_ltk; 5273 uint8_t ltk[16]; 5274 bool auth_required; 5275 int authenticated; 5276 bool trigger_reencryption; 5277 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 5278 if (IS_RESPONDER(sm_conn->sm_role)){ 5279 switch (sm_conn->sm_engine_state){ 5280 case SM_GENERAL_IDLE: 5281 case SM_RESPONDER_IDLE: 5282 switch (sm_conn->sm_irk_lookup_state){ 5283 case IRK_LOOKUP_SUCCEEDED: 5284 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 5285 have_ltk = !sm_is_null_key(ltk); 5286 log_info("have ltk %u", have_ltk); 5287 if (have_ltk){ 5288 sm_conn->sm_pairing_requested = true; 5289 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5290 sm_reencryption_started(sm_conn); 5291 break; 5292 } 5293 /* fall through */ 5294 5295 case IRK_LOOKUP_FAILED: 5296 sm_conn->sm_pairing_requested = true; 5297 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5298 sm_pairing_started(sm_conn); 5299 break; 5300 default: 5301 log_info("irk lookup pending"); 5302 sm_conn->sm_pairing_requested = true; 5303 break; 5304 } 5305 break; 5306 default: 5307 break; 5308 } 5309 } else { 5310 // used as a trigger to start central/master/initiator security procedures 5311 switch (sm_conn->sm_engine_state){ 5312 case SM_INITIATOR_CONNECTED: 5313 switch (sm_conn->sm_irk_lookup_state){ 5314 case IRK_LOOKUP_SUCCEEDED: 5315 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); 5316 have_ltk = !sm_is_null_key(ltk); 5317 auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; 5318 // re-encrypt is sufficient if we have ltk and that is either already authenticated or we don't require authentication 5319 trigger_reencryption = have_ltk && ((authenticated != 0) || (auth_required == false)); 5320 log_info("have ltk %u, authenticated %u, auth required %u => reencrypt %u", have_ltk, authenticated, auth_required, trigger_reencryption); 5321 if (trigger_reencryption){ 5322 sm_conn->sm_pairing_requested = true; 5323 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 5324 break; 5325 } 5326 /* fall through */ 5327 5328 case IRK_LOOKUP_FAILED: 5329 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5330 break; 5331 default: 5332 log_info("irk lookup pending"); 5333 sm_conn->sm_pairing_requested = true; 5334 break; 5335 } 5336 break; 5337 case SM_GENERAL_REENCRYPTION_FAILED: 5338 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5339 break; 5340 case SM_GENERAL_IDLE: 5341 sm_conn->sm_pairing_requested = true; 5342 break; 5343 default: 5344 break; 5345 } 5346 } 5347 sm_trigger_run(); 5348 } 5349 5350 // called by client app on authorization request 5351 void sm_authorization_decline(hci_con_handle_t con_handle){ 5352 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5353 if (!sm_conn) return; // wrong connection 5354 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 5355 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 5356 } 5357 5358 void sm_authorization_grant(hci_con_handle_t con_handle){ 5359 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5360 if (!sm_conn) return; // wrong connection 5361 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 5362 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 5363 } 5364 5365 // GAP Bonding API 5366 5367 void sm_bonding_decline(hci_con_handle_t con_handle){ 5368 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5369 if (!sm_conn) return; // wrong connection 5370 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 5371 log_info("decline, state %u", sm_conn->sm_engine_state); 5372 switch(sm_conn->sm_engine_state){ 5373 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5374 case SM_SC_W4_USER_RESPONSE: 5375 case SM_SC_W4_CONFIRMATION: 5376 case SM_SC_W4_PUBLIC_KEY_COMMAND: 5377 #endif 5378 case SM_PH1_W4_USER_RESPONSE: 5379 switch (setup->sm_stk_generation_method){ 5380 case PK_RESP_INPUT: 5381 case PK_INIT_INPUT: 5382 case PK_BOTH_INPUT: 5383 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 5384 break; 5385 case NUMERIC_COMPARISON: 5386 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 5387 break; 5388 case JUST_WORKS: 5389 case OOB: 5390 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 5391 break; 5392 default: 5393 btstack_assert(false); 5394 break; 5395 } 5396 break; 5397 default: 5398 break; 5399 } 5400 sm_trigger_run(); 5401 } 5402 5403 void sm_just_works_confirm(hci_con_handle_t con_handle){ 5404 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5405 if (!sm_conn) return; // wrong connection 5406 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 5407 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5408 if (setup->sm_use_secure_connections){ 5409 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 5410 } else { 5411 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); 5412 } 5413 } 5414 5415 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5416 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5417 sm_sc_prepare_dhkey_check(sm_conn); 5418 } 5419 #endif 5420 5421 sm_trigger_run(); 5422 } 5423 5424 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5425 // for now, it's the same 5426 sm_just_works_confirm(con_handle); 5427 } 5428 5429 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5430 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5431 if (!sm_conn) return; // wrong connection 5432 sm_reset_tk(); 5433 big_endian_store_32(setup->sm_tk, 12, passkey); 5434 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5435 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5436 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); 5437 } 5438 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5439 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5440 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5441 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5442 sm_sc_start_calculating_local_confirm(sm_conn); 5443 } 5444 #endif 5445 sm_trigger_run(); 5446 } 5447 5448 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5449 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5450 if (!sm_conn) return; // wrong connection 5451 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5452 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5453 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5454 switch (action){ 5455 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5456 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5457 flags |= (1u << action); 5458 break; 5459 case SM_KEYPRESS_PASSKEY_CLEARED: 5460 // clear counter, keypress & erased flags + set passkey cleared 5461 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5462 break; 5463 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5464 if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)) != 0u){ 5465 // erase actions queued 5466 num_actions--; 5467 if (num_actions == 0u){ 5468 // clear counter, keypress & erased flags 5469 flags &= 0x19u; 5470 } 5471 break; 5472 } 5473 num_actions++; 5474 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5475 break; 5476 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5477 if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)) != 0u){ 5478 // enter actions queued 5479 num_actions--; 5480 if (num_actions == 0u){ 5481 // clear counter, keypress & erased flags 5482 flags &= 0x19u; 5483 } 5484 break; 5485 } 5486 num_actions++; 5487 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5488 break; 5489 default: 5490 break; 5491 } 5492 setup->sm_keypress_notification = (num_actions << 5) | flags; 5493 sm_trigger_run(); 5494 } 5495 5496 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5497 static void sm_handle_random_result_oob(void * arg){ 5498 UNUSED(arg); 5499 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5500 sm_trigger_run(); 5501 } 5502 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5503 5504 static btstack_crypto_random_t sm_crypto_random_oob_request; 5505 5506 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5507 sm_sc_oob_callback = callback; 5508 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5509 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5510 return 0; 5511 } 5512 #endif 5513 5514 /** 5515 * @brief Get Identity Resolving state 5516 * @param con_handle 5517 * @return irk_lookup_state_t 5518 */ 5519 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5520 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5521 if (!sm_conn) return IRK_LOOKUP_IDLE; 5522 return sm_conn->sm_irk_lookup_state; 5523 } 5524 5525 /** 5526 * @brief Identify device in LE Device DB 5527 * @param handle 5528 * @return index from le_device_db or -1 if not found/identified 5529 */ 5530 int sm_le_device_index(hci_con_handle_t con_handle ){ 5531 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5532 if (!sm_conn) return -1; 5533 return sm_conn->sm_le_db_index; 5534 } 5535 5536 uint8_t sm_get_ltk(hci_con_handle_t con_handle, sm_key_t ltk){ 5537 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 5538 if (hci_connection == NULL){ 5539 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 5540 } 5541 if (hci_connection->link_key_type == INVALID_LINK_KEY){ 5542 return ERROR_CODE_PIN_OR_KEY_MISSING; 5543 } 5544 memcpy(ltk, hci_connection->link_key, 16); 5545 return ERROR_CODE_SUCCESS; 5546 } 5547 5548 static int gap_random_address_type_requires_updates(void){ 5549 switch (gap_random_adress_type){ 5550 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5551 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5552 return 0; 5553 default: 5554 return 1; 5555 } 5556 } 5557 5558 static uint8_t own_address_type(void){ 5559 switch (gap_random_adress_type){ 5560 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5561 return BD_ADDR_TYPE_LE_PUBLIC; 5562 default: 5563 return BD_ADDR_TYPE_LE_RANDOM; 5564 } 5565 } 5566 5567 // GAP LE API 5568 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5569 gap_random_address_update_stop(); 5570 gap_random_adress_type = random_address_type; 5571 hci_le_set_own_address_type(own_address_type()); 5572 if (!gap_random_address_type_requires_updates()) return; 5573 gap_random_address_update_start(); 5574 gap_random_address_trigger(); 5575 } 5576 5577 gap_random_address_type_t gap_random_address_get_mode(void){ 5578 return gap_random_adress_type; 5579 } 5580 5581 void gap_random_address_set_update_period(int period_ms){ 5582 gap_random_adress_update_period = period_ms; 5583 if (!gap_random_address_type_requires_updates()) return; 5584 gap_random_address_update_stop(); 5585 gap_random_address_update_start(); 5586 } 5587 5588 void gap_random_address_set(const bd_addr_t addr){ 5589 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5590 (void)memcpy(sm_random_address, addr, 6); 5591 // assert msb bits are set to '11' 5592 sm_random_address[0] |= 0xc0; 5593 hci_le_random_address_set(sm_random_address); 5594 } 5595 5596 #ifdef ENABLE_LE_PERIPHERAL 5597 /* 5598 * @brief Set Advertisement Paramters 5599 * @param adv_int_min 5600 * @param adv_int_max 5601 * @param adv_type 5602 * @param direct_address_type 5603 * @param direct_address 5604 * @param channel_map 5605 * @param filter_policy 5606 * 5607 * @note own_address_type is used from gap_random_address_set_mode 5608 */ 5609 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5610 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5611 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5612 direct_address_typ, direct_address, channel_map, filter_policy); 5613 } 5614 #endif 5615 5616 bool gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5617 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5618 // wrong connection 5619 if (!sm_conn) return false; 5620 // already encrypted 5621 if (sm_conn->sm_connection_encrypted) return false; 5622 // irk status? 5623 switch(sm_conn->sm_irk_lookup_state){ 5624 case IRK_LOOKUP_FAILED: 5625 // done, cannot setup encryption 5626 return false; 5627 case IRK_LOOKUP_SUCCEEDED: 5628 break; 5629 default: 5630 // IR Lookup pending 5631 return true; 5632 } 5633 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5634 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return false; 5635 if (sm_conn->sm_role != 0){ 5636 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5637 } else { 5638 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5639 } 5640 } 5641 5642 void sm_set_secure_connections_only_mode(bool enable){ 5643 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5644 sm_sc_only_mode = enable; 5645 #else 5646 // SC Only mode not possible without support for SC 5647 btstack_assert(enable == false); 5648 #endif 5649 } 5650 5651 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) 5652 void sm_test_enable_secure_connections_debug_keys(void) { 5653 log_info("Enable LE Secure Connection Debug Keys for testing"); 5654 sm_sc_debug_keys_enabled = true; 5655 // set debug key 5656 sm_ec_generate_new_key(); 5657 } 5658 #endif 5659 5660 const uint8_t * gap_get_persistent_irk(void){ 5661 return sm_persistent_irk; 5662 } 5663 5664 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5665 int index = sm_le_device_db_index_lookup(address_type, address); 5666 if (index >= 0){ 5667 sm_remove_le_device_db_entry(index); 5668 } 5669 } 5670