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 int err; 2412 UNUSED(err); 2413 2414 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2415 // assert ec key is ready 2416 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2417 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2418 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2419 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2420 sm_ec_generate_new_key(); 2421 } 2422 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2423 continue; 2424 } 2425 } 2426 #endif 2427 2428 switch (sm_connection->sm_engine_state) { 2429 #ifdef ENABLE_LE_PERIPHERAL 2430 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2431 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2432 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2433 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2434 case SM_SC_RECEIVED_LTK_REQUEST: 2435 #endif 2436 #endif 2437 #ifdef ENABLE_LE_CENTRAL 2438 case SM_INITIATOR_PH4_HAS_LTK: 2439 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2440 #endif 2441 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2442 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2443 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2444 #endif 2445 // just lock context 2446 break; 2447 default: 2448 done = false; 2449 break; 2450 } 2451 if (done){ 2452 sm_active_connection_handle = sm_connection->sm_handle; 2453 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); 2454 } 2455 } 2456 } 2457 2458 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2459 int i; 2460 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2461 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2462 uint8_t action = 0; 2463 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2464 if ((flags & (1u<<i)) != 0u){ 2465 bool clear_flag = true; 2466 switch (i){ 2467 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2468 case SM_KEYPRESS_PASSKEY_CLEARED: 2469 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2470 default: 2471 break; 2472 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2473 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2474 num_actions--; 2475 clear_flag = num_actions == 0u; 2476 break; 2477 } 2478 if (clear_flag){ 2479 flags &= ~(1<<i); 2480 } 2481 action = i; 2482 break; 2483 } 2484 } 2485 setup->sm_keypress_notification = (num_actions << 5) | flags; 2486 2487 // send keypress notification 2488 uint8_t buffer[2]; 2489 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2490 buffer[1] = action; 2491 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2492 2493 // try 2494 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2495 } 2496 2497 static void sm_run_distribute_keys(sm_connection_t * connection){ 2498 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) != 0u){ 2499 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2500 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2501 uint8_t buffer[17]; 2502 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2503 reverse_128(setup->sm_ltk, &buffer[1]); 2504 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2505 sm_timeout_reset(connection); 2506 return; 2507 } 2508 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION) != 0u){ 2509 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2510 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2511 uint8_t buffer[11]; 2512 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2513 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2514 reverse_64(setup->sm_local_rand, &buffer[3]); 2515 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2516 sm_timeout_reset(connection); 2517 return; 2518 } 2519 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ 2520 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2521 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2522 uint8_t buffer[17]; 2523 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2524 reverse_128(sm_persistent_irk, &buffer[1]); 2525 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2526 sm_timeout_reset(connection); 2527 return; 2528 } 2529 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0u){ 2530 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2531 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2532 bd_addr_t local_address; 2533 uint8_t buffer[8]; 2534 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2535 switch (gap_random_address_get_mode()){ 2536 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2537 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2538 // public or static random 2539 gap_le_get_own_address(&buffer[1], local_address); 2540 break; 2541 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2542 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2543 // fallback to public 2544 gap_local_bd_addr(local_address); 2545 buffer[1] = 0; 2546 break; 2547 default: 2548 btstack_assert(false); 2549 break; 2550 } 2551 reverse_bd_addr(local_address, &buffer[2]); 2552 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2553 sm_timeout_reset(connection); 2554 return; 2555 } 2556 if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION) != 0u){ 2557 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2558 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2559 2560 #ifdef ENABLE_LE_SIGNED_WRITE 2561 // hack to reproduce test runs 2562 if (test_use_fixed_local_csrk){ 2563 memset(setup->sm_local_csrk, 0xcc, 16); 2564 } 2565 2566 // store local CSRK 2567 if (setup->sm_le_device_index >= 0){ 2568 log_info("sm: store local CSRK"); 2569 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2570 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2571 } 2572 #endif 2573 2574 uint8_t buffer[17]; 2575 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2576 reverse_128(setup->sm_local_csrk, &buffer[1]); 2577 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2578 sm_timeout_reset(connection); 2579 return; 2580 } 2581 btstack_assert(false); 2582 } 2583 2584 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2585 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2586 // requirements to derive link key from LE: 2587 // - use secure connections 2588 if (setup->sm_use_secure_connections == 0) return false; 2589 // - bonding needs to be enabled: 2590 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; 2591 if (!bonding_enabled) return false; 2592 // - need identity address / public addr 2593 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2594 if (!have_identity_address_info) return false; 2595 // - 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) 2596 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2597 // If SC is authenticated, we consider it safe to overwrite a stored key. 2598 // 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. 2599 uint8_t link_key[16]; 2600 link_key_type_t link_key_type; 2601 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2602 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2603 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2604 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2605 return false; 2606 } 2607 // get started (all of the above are true) 2608 return true; 2609 #else 2610 UNUSED(sm_connection); 2611 return false; 2612 #endif 2613 } 2614 2615 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2616 static bool sm_ctkd_from_classic(sm_connection_t * sm_connection){ 2617 hci_connection_t * hci_connection = hci_connection_for_handle(sm_connection->sm_handle); 2618 btstack_assert(hci_connection != NULL); 2619 // requirements to derive ltk from BR/EDR: 2620 // - BR/EDR uses secure connections 2621 if (gap_secure_connection_for_link_key_type(hci_connection->link_key_type) == false) return false; 2622 // - 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) 2623 bool link_key_authenticated = gap_authenticated_for_link_key_type(hci_connection->link_key_type); 2624 if (link_key_authenticated) return true; 2625 int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, hci_connection->address); 2626 if (index >= 0){ 2627 int ltk_authenticated; 2628 sm_key_t ltk; 2629 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, <k_authenticated, NULL, NULL); 2630 bool have_ltk = !sm_is_null_key(ltk); 2631 if (have_ltk && ltk_authenticated) return false; 2632 } 2633 return true; 2634 } 2635 #endif 2636 2637 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2638 if (sm_ctkd_from_le(connection)){ 2639 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; 2640 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2641 } else { 2642 connection->sm_engine_state = SM_RESPONDER_IDLE; 2643 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2644 sm_done_for_handle(connection->sm_handle); 2645 } 2646 } 2647 2648 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2649 if (sm_ctkd_from_le(connection)){ 2650 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; 2651 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2652 } else { 2653 sm_master_pairing_success(connection); 2654 } 2655 } 2656 2657 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2658 static void sm_run_state_sc_send_confirmation(sm_connection_t *connection) { 2659 uint8_t buffer[17]; 2660 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2661 reverse_128(setup->sm_local_confirm, &buffer[1]); 2662 if (IS_RESPONDER(connection->sm_role)){ 2663 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2664 } else { 2665 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2666 } 2667 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2668 sm_timeout_reset(connection); 2669 } 2670 2671 static void sm_run_state_sc_send_pairing_random(sm_connection_t *connection) { 2672 uint8_t buffer[17]; 2673 buffer[0] = SM_CODE_PAIRING_RANDOM; 2674 reverse_128(setup->sm_local_nonce, &buffer[1]); 2675 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2676 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2677 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2678 if (IS_RESPONDER(connection->sm_role)){ 2679 // responder 2680 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2681 } else { 2682 // initiator 2683 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2684 } 2685 } else { 2686 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2687 if (IS_RESPONDER(connection->sm_role)){ 2688 // responder 2689 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2690 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2691 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2692 } else { 2693 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2694 sm_sc_prepare_dhkey_check(connection); 2695 } 2696 } else { 2697 // initiator 2698 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2699 } 2700 } 2701 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2702 sm_timeout_reset(connection); 2703 } 2704 2705 static void sm_run_state_sc_send_dhkey_check_command(sm_connection_t *connection) { 2706 uint8_t buffer[17]; 2707 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2708 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2709 2710 if (IS_RESPONDER(connection->sm_role)){ 2711 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2712 } else { 2713 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2714 } 2715 2716 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2717 sm_timeout_reset(connection); 2718 } 2719 2720 static void sm_run_state_sc_send_public_key_command(sm_connection_t *connection) { 2721 bool trigger_user_response = false; 2722 bool trigger_start_calculating_local_confirm = false; 2723 uint8_t buffer[65]; 2724 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2725 // 2726 reverse_256(&ec_q[0], &buffer[1]); 2727 reverse_256(&ec_q[32], &buffer[33]); 2728 2729 #ifdef ENABLE_TESTING_SUPPORT 2730 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2731 log_info("testing_support: invalidating public key"); 2732 // flip single bit of public key coordinate 2733 buffer[1] ^= 1; 2734 } 2735 #endif 2736 2737 // stk generation method 2738 // passkey entry: notify app to show passkey or to request passkey 2739 switch (setup->sm_stk_generation_method){ 2740 case JUST_WORKS: 2741 case NUMERIC_COMPARISON: 2742 if (IS_RESPONDER(connection->sm_role)){ 2743 // responder 2744 trigger_start_calculating_local_confirm = true; 2745 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2746 } else { 2747 // initiator 2748 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2749 } 2750 break; 2751 case PK_INIT_INPUT: 2752 case PK_RESP_INPUT: 2753 case PK_BOTH_INPUT: 2754 // use random TK for display 2755 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2756 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2757 setup->sm_passkey_bit = 0; 2758 2759 if (IS_RESPONDER(connection->sm_role)){ 2760 // responder 2761 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2762 } else { 2763 // initiator 2764 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2765 } 2766 trigger_user_response = true; 2767 break; 2768 case OOB: 2769 if (IS_RESPONDER(connection->sm_role)){ 2770 // responder 2771 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2772 } else { 2773 // initiator 2774 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2775 } 2776 break; 2777 default: 2778 btstack_assert(false); 2779 break; 2780 } 2781 2782 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2783 sm_timeout_reset(connection); 2784 2785 // trigger user response and calc confirm after sending pdu 2786 if (trigger_user_response){ 2787 sm_trigger_user_response(connection); 2788 } 2789 if (trigger_start_calculating_local_confirm){ 2790 sm_sc_start_calculating_local_confirm(connection); 2791 } 2792 } 2793 #endif 2794 2795 static bool sm_run_non_connection_logic(void){ 2796 bool done;; 2797 2798 done = sm_run_dpkg(); 2799 if (done) return true; 2800 2801 done = sm_run_rau(); 2802 if (done) return true; 2803 2804 done = sm_run_irk_lookup(); 2805 if (done) return true; 2806 2807 done = sm_run_oob(); 2808 return done; 2809 } 2810 2811 static void sm_run(void){ 2812 2813 // assert that stack has already bootet 2814 if (hci_get_state() != HCI_STATE_WORKING) return; 2815 2816 // assert that we can send at least commands 2817 if (!hci_can_send_command_packet_now()) return; 2818 2819 // pause until IR/ER are ready 2820 if (sm_persistent_keys_random_active) return; 2821 2822 // non-connection related behaviour 2823 bool done = sm_run_non_connection_logic(); 2824 if (done) return; 2825 2826 // assert that we can send at least commands - cmd might have been sent by crypto engine 2827 if (!hci_can_send_command_packet_now()) return; 2828 2829 // handle basic actions that don't requires the full context 2830 done = sm_run_basic(); 2831 if (done) return; 2832 2833 // 2834 // active connection handling 2835 // -- use loop to handle next connection if lock on setup context is released 2836 2837 while (true) { 2838 2839 sm_run_activate_connection(); 2840 2841 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2842 2843 // 2844 // active connection handling 2845 // 2846 2847 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2848 if (!connection) { 2849 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2850 return; 2851 } 2852 2853 // assert that we could send a SM PDU - not needed for all of the following 2854 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2855 log_info("cannot send now, requesting can send now event"); 2856 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2857 return; 2858 } 2859 2860 // send keypress notifications 2861 if (setup->sm_keypress_notification != 0u){ 2862 sm_run_send_keypress_notification(connection); 2863 return; 2864 } 2865 2866 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2867 // assert that sm cmac engine is ready 2868 if (sm_cmac_ready() == false){ 2869 break; 2870 } 2871 #endif 2872 2873 int key_distribution_flags; 2874 UNUSED(key_distribution_flags); 2875 #ifdef ENABLE_LE_PERIPHERAL 2876 int err; 2877 bool have_ltk; 2878 uint8_t ltk[16]; 2879 #endif 2880 2881 log_info("sm_run: state %u", connection->sm_engine_state); 2882 switch (connection->sm_engine_state){ 2883 2884 // secure connections, initiator + responding states 2885 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2886 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2887 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2888 sm_sc_calculate_local_confirm(connection); 2889 break; 2890 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2891 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2892 sm_sc_calculate_remote_confirm(connection); 2893 break; 2894 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2895 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2896 sm_sc_calculate_f6_for_dhkey_check(connection); 2897 break; 2898 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2899 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2900 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2901 break; 2902 case SM_SC_W2_CALCULATE_F5_SALT: 2903 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2904 f5_calculate_salt(connection); 2905 break; 2906 case SM_SC_W2_CALCULATE_F5_MACKEY: 2907 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2908 f5_calculate_mackey(connection); 2909 break; 2910 case SM_SC_W2_CALCULATE_F5_LTK: 2911 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2912 f5_calculate_ltk(connection); 2913 break; 2914 case SM_SC_W2_CALCULATE_G2: 2915 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2916 g2_calculate(connection); 2917 break; 2918 #endif 2919 2920 #ifdef ENABLE_LE_CENTRAL 2921 // initiator side 2922 2923 case SM_INITIATOR_PH4_HAS_LTK: { 2924 sm_reset_setup(); 2925 sm_load_security_info(connection); 2926 2927 // cache key before using 2928 sm_cache_ltk(connection, setup->sm_peer_ltk); 2929 2930 sm_key_t peer_ltk_flipped; 2931 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2932 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2933 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2934 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2935 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2936 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2937 2938 // notify after sending 2939 sm_reencryption_started(connection); 2940 return; 2941 } 2942 2943 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2944 sm_reset_setup(); 2945 sm_init_setup(connection); 2946 2947 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2948 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2949 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2950 sm_timeout_reset(connection); 2951 2952 // notify after sending 2953 sm_pairing_started(connection); 2954 break; 2955 #endif 2956 2957 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2958 case SM_SC_SEND_PUBLIC_KEY_COMMAND: 2959 sm_run_state_sc_send_public_key_command(connection); 2960 break; 2961 case SM_SC_SEND_CONFIRMATION: 2962 sm_run_state_sc_send_confirmation(connection); 2963 break; 2964 case SM_SC_SEND_PAIRING_RANDOM: 2965 sm_run_state_sc_send_pairing_random(connection); 2966 break; 2967 case SM_SC_SEND_DHKEY_CHECK_COMMAND: 2968 sm_run_state_sc_send_dhkey_check_command(connection); 2969 break; 2970 #endif 2971 2972 #ifdef ENABLE_LE_PERIPHERAL 2973 2974 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2975 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2976 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2977 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2978 sm_timeout_start(connection); 2979 break; 2980 } 2981 2982 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2983 case SM_SC_RECEIVED_LTK_REQUEST: 2984 switch (connection->sm_irk_lookup_state){ 2985 case IRK_LOOKUP_SUCCEEDED: 2986 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2987 // start using context by loading security info 2988 sm_reset_setup(); 2989 sm_load_security_info(connection); 2990 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2991 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2992 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2993 sm_reencryption_started(connection); 2994 sm_trigger_run(); 2995 break; 2996 } 2997 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2998 connection->sm_engine_state = SM_RESPONDER_IDLE; 2999 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 3000 return; 3001 default: 3002 // just wait until IRK lookup is completed 3003 break; 3004 } 3005 break; 3006 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 3007 3008 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 3009 sm_reset_setup(); 3010 3011 // handle Pairing Request with LTK available 3012 switch (connection->sm_irk_lookup_state) { 3013 case IRK_LOOKUP_SUCCEEDED: 3014 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3015 have_ltk = !sm_is_null_key(ltk); 3016 if (have_ltk){ 3017 log_info("pairing request but LTK available"); 3018 // emit re-encryption start/fail sequence 3019 sm_reencryption_started(connection); 3020 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 3021 } 3022 break; 3023 default: 3024 break; 3025 } 3026 3027 sm_init_setup(connection); 3028 3029 // recover pairing request 3030 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3031 err = sm_stk_generation_init(connection); 3032 3033 #ifdef ENABLE_TESTING_SUPPORT 3034 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 3035 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 3036 err = test_pairing_failure; 3037 } 3038 #endif 3039 if (err != 0){ 3040 // emit pairing started/failed sequence 3041 sm_pairing_started(connection); 3042 sm_pairing_error(connection, err); 3043 sm_trigger_run(); 3044 break; 3045 } 3046 3047 sm_timeout_start(connection); 3048 3049 // generate random number first, if we need to show passkey, otherwise send response 3050 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3051 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 3052 break; 3053 } 3054 3055 /* fall through */ 3056 3057 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 3058 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 3059 3060 // start with initiator key dist flags 3061 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 3062 3063 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3064 // LTK (= encryption information & master identification) only exchanged for LE Legacy Connection 3065 if (setup->sm_use_secure_connections){ 3066 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3067 } 3068 #endif 3069 // setup in response 3070 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); 3071 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); 3072 3073 // update key distribution after ENC was dropped 3074 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)); 3075 3076 if (setup->sm_use_secure_connections){ 3077 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 3078 } else { 3079 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 3080 } 3081 3082 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3083 sm_timeout_reset(connection); 3084 3085 // notify after sending 3086 sm_pairing_started(connection); 3087 3088 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3089 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 3090 sm_trigger_user_response(connection); 3091 } 3092 return; 3093 #endif 3094 3095 case SM_PH2_SEND_PAIRING_RANDOM: { 3096 uint8_t buffer[17]; 3097 buffer[0] = SM_CODE_PAIRING_RANDOM; 3098 reverse_128(setup->sm_local_random, &buffer[1]); 3099 if (IS_RESPONDER(connection->sm_role)){ 3100 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 3101 } else { 3102 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 3103 } 3104 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3105 sm_timeout_reset(connection); 3106 break; 3107 } 3108 3109 case SM_PH2_C1_GET_ENC_A: 3110 // already busy? 3111 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3112 // calculate confirm using aes128 engine - step 1 3113 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); 3114 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 3115 sm_aes128_state = SM_AES128_ACTIVE; 3116 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); 3117 break; 3118 3119 case SM_PH2_C1_GET_ENC_C: 3120 // already busy? 3121 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3122 // calculate m_confirm using aes128 engine - step 1 3123 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); 3124 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 3125 sm_aes128_state = SM_AES128_ACTIVE; 3126 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); 3127 break; 3128 3129 case SM_PH2_CALC_STK: 3130 // already busy? 3131 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3132 // calculate STK 3133 if (IS_RESPONDER(connection->sm_role)){ 3134 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 3135 } else { 3136 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3137 } 3138 connection->sm_engine_state = SM_PH2_W4_STK; 3139 sm_aes128_state = SM_AES128_ACTIVE; 3140 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); 3141 break; 3142 3143 case SM_PH3_Y_GET_ENC: 3144 // already busy? 3145 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3146 // PH3B2 - calculate Y from - enc 3147 3148 // dm helper (was sm_dm_r_prime) 3149 // r' = padding || r 3150 // r - 64 bit value 3151 memset(&sm_aes128_plaintext[0], 0, 8); 3152 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3153 3154 // Y = dm(DHK, Rand) 3155 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3156 sm_aes128_state = SM_AES128_ACTIVE; 3157 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); 3158 break; 3159 3160 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3161 uint8_t buffer[17]; 3162 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3163 reverse_128(setup->sm_local_confirm, &buffer[1]); 3164 if (IS_RESPONDER(connection->sm_role)){ 3165 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3166 } else { 3167 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3168 } 3169 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3170 sm_timeout_reset(connection); 3171 return; 3172 } 3173 #ifdef ENABLE_LE_PERIPHERAL 3174 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3175 // cache key before using 3176 sm_cache_ltk(connection, setup->sm_ltk); 3177 sm_key_t stk_flipped; 3178 reverse_128(setup->sm_ltk, stk_flipped); 3179 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3180 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3181 return; 3182 } 3183 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3184 // allow to override LTK 3185 if (sm_get_ltk_callback != NULL){ 3186 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3187 } 3188 // cache key before using 3189 sm_cache_ltk(connection, setup->sm_ltk); 3190 sm_key_t ltk_flipped; 3191 reverse_128(setup->sm_ltk, ltk_flipped); 3192 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3193 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3194 return; 3195 } 3196 3197 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3198 // already busy? 3199 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3200 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3201 3202 sm_reset_setup(); 3203 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3204 3205 sm_reencryption_started(connection); 3206 3207 // dm helper (was sm_dm_r_prime) 3208 // r' = padding || r 3209 // r - 64 bit value 3210 memset(&sm_aes128_plaintext[0], 0, 8); 3211 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3212 3213 // Y = dm(DHK, Rand) 3214 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3215 sm_aes128_state = SM_AES128_ACTIVE; 3216 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); 3217 return; 3218 #endif 3219 #ifdef ENABLE_LE_CENTRAL 3220 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3221 // cache key before using 3222 sm_cache_ltk(connection, setup->sm_ltk); 3223 3224 sm_key_t stk_flipped; 3225 reverse_128(setup->sm_ltk, stk_flipped); 3226 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3227 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3228 return; 3229 } 3230 #endif 3231 3232 case SM_PH3_DISTRIBUTE_KEYS: 3233 // send next key 3234 if (setup->sm_key_distribution_send_set != 0){ 3235 sm_run_distribute_keys(connection); 3236 } 3237 3238 // more to send? 3239 if (setup->sm_key_distribution_send_set != 0){ 3240 return; 3241 } 3242 3243 // keys are sent 3244 if (IS_RESPONDER(connection->sm_role)){ 3245 // slave -> receive master keys if any 3246 if (sm_key_distribution_all_received()){ 3247 sm_key_distribution_handle_all_received(connection); 3248 sm_key_distribution_complete_responder(connection); 3249 // start CTKD right away 3250 continue; 3251 } else { 3252 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3253 } 3254 } else { 3255 sm_master_pairing_success(connection); 3256 } 3257 break; 3258 3259 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3260 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3261 // fill in sm setup (lite version of sm_init_setup) 3262 sm_reset_setup(); 3263 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3264 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3265 setup->sm_s_addr_type = connection->sm_own_addr_type; 3266 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3267 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3268 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3269 setup->sm_use_secure_connections = true; 3270 sm_ctkd_fetch_br_edr_link_key(connection); 3271 3272 // Enc Key and IRK if requested 3273 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3274 #ifdef ENABLE_LE_SIGNED_WRITE 3275 // Plus signing key if supported 3276 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3277 #endif 3278 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3279 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3280 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3281 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3282 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3283 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3284 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3285 3286 // set state and send pairing response 3287 sm_timeout_start(connection); 3288 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3289 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3290 break; 3291 3292 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3293 // fill in sm setup (lite version of sm_init_setup) 3294 sm_reset_setup(); 3295 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3296 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3297 setup->sm_s_addr_type = connection->sm_own_addr_type; 3298 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3299 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3300 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3301 setup->sm_use_secure_connections = true; 3302 sm_ctkd_fetch_br_edr_link_key(connection); 3303 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3304 3305 // Enc Key and IRK if requested 3306 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3307 #ifdef ENABLE_LE_SIGNED_WRITE 3308 // Plus signing key if supported 3309 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3310 #endif 3311 // drop flags not requested by initiator 3312 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3313 3314 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3315 // - the IO Capability field, 3316 // - the OOB data flag field, and 3317 // - all bits in the Auth Req field except the CT2 bit. 3318 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3319 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3320 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3321 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3322 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3323 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3324 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3325 3326 // configure key distribution, LTK is derived locally 3327 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3328 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3329 3330 // set state and send pairing response 3331 sm_timeout_start(connection); 3332 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3333 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3334 break; 3335 case SM_BR_EDR_DISTRIBUTE_KEYS: 3336 // send next key 3337 if (setup->sm_key_distribution_send_set != 0) { 3338 sm_run_distribute_keys(connection); 3339 } 3340 3341 // more to send? 3342 if (setup->sm_key_distribution_send_set != 0){ 3343 return; 3344 } 3345 3346 // keys are sent 3347 if (IS_RESPONDER(connection->sm_role)) { 3348 // responder -> receive master keys if there are any 3349 if (!sm_key_distribution_all_received()){ 3350 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3351 break; 3352 } 3353 } 3354 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3355 sm_ctkd_start_from_br_edr(connection); 3356 continue; 3357 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3358 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3359 h6_calculate_ilk_from_le_ltk(connection); 3360 break; 3361 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3362 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3363 h6_calculate_br_edr_link_key(connection); 3364 break; 3365 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3366 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3367 h7_calculate_ilk_from_le_ltk(connection); 3368 break; 3369 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3370 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3371 h6_calculate_ilk_from_br_edr(connection); 3372 break; 3373 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3374 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3375 h6_calculate_le_ltk(connection); 3376 break; 3377 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3378 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3379 h7_calculate_ilk_from_br_edr(connection); 3380 break; 3381 #endif 3382 3383 default: 3384 break; 3385 } 3386 3387 // check again if active connection was released 3388 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3389 } 3390 } 3391 3392 // sm_aes128_state stays active 3393 static void sm_handle_encryption_result_enc_a(void *arg){ 3394 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3395 sm_aes128_state = SM_AES128_IDLE; 3396 3397 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3398 if (connection == NULL) return; 3399 3400 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3401 sm_aes128_state = SM_AES128_ACTIVE; 3402 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); 3403 } 3404 3405 static void sm_handle_encryption_result_enc_b(void *arg){ 3406 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3407 sm_aes128_state = SM_AES128_IDLE; 3408 3409 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3410 if (connection == NULL) return; 3411 3412 log_info_key("c1!", setup->sm_local_confirm); 3413 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3414 sm_trigger_run(); 3415 } 3416 3417 // sm_aes128_state stays active 3418 static void sm_handle_encryption_result_enc_c(void *arg){ 3419 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3420 sm_aes128_state = SM_AES128_IDLE; 3421 3422 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3423 if (connection == NULL) return; 3424 3425 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3426 sm_aes128_state = SM_AES128_ACTIVE; 3427 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); 3428 } 3429 3430 static void sm_handle_encryption_result_enc_d(void * arg){ 3431 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3432 sm_aes128_state = SM_AES128_IDLE; 3433 3434 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3435 if (connection == NULL) return; 3436 3437 log_info_key("c1!", sm_aes128_ciphertext); 3438 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3439 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3440 sm_trigger_run(); 3441 return; 3442 } 3443 if (IS_RESPONDER(connection->sm_role)){ 3444 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3445 sm_trigger_run(); 3446 } else { 3447 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3448 sm_aes128_state = SM_AES128_ACTIVE; 3449 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); 3450 } 3451 } 3452 3453 static void sm_handle_encryption_result_enc_stk(void *arg){ 3454 sm_aes128_state = SM_AES128_IDLE; 3455 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3456 3457 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3458 if (connection == NULL) return; 3459 3460 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3461 log_info_key("stk", setup->sm_ltk); 3462 if (IS_RESPONDER(connection->sm_role)){ 3463 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3464 } else { 3465 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3466 } 3467 sm_trigger_run(); 3468 } 3469 3470 // sm_aes128_state stays active 3471 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3472 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3473 sm_aes128_state = SM_AES128_IDLE; 3474 3475 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3476 if (connection == NULL) return; 3477 3478 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3479 log_info_hex16("y", setup->sm_local_y); 3480 // PH3B3 - calculate EDIV 3481 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3482 log_info_hex16("ediv", setup->sm_local_ediv); 3483 // PH3B4 - calculate LTK - enc 3484 // LTK = d1(ER, DIV, 0)) 3485 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3486 sm_aes128_state = SM_AES128_ACTIVE; 3487 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); 3488 } 3489 3490 #ifdef ENABLE_LE_PERIPHERAL 3491 // sm_aes128_state stays active 3492 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3493 sm_aes128_state = SM_AES128_IDLE; 3494 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3495 3496 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3497 if (connection == NULL) return; 3498 3499 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3500 log_info_hex16("y", setup->sm_local_y); 3501 3502 // PH3B3 - calculate DIV 3503 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3504 log_info_hex16("ediv", setup->sm_local_ediv); 3505 // PH3B4 - calculate LTK - enc 3506 // LTK = d1(ER, DIV, 0)) 3507 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3508 sm_aes128_state = SM_AES128_ACTIVE; 3509 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); 3510 } 3511 #endif 3512 3513 // sm_aes128_state stays active 3514 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3515 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3516 sm_aes128_state = SM_AES128_IDLE; 3517 3518 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3519 if (connection == NULL) return; 3520 3521 log_info_key("ltk", setup->sm_ltk); 3522 // calc CSRK next 3523 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3524 sm_aes128_state = SM_AES128_ACTIVE; 3525 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); 3526 } 3527 3528 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3529 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3530 sm_aes128_state = SM_AES128_IDLE; 3531 3532 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3533 if (connection == NULL) return; 3534 3535 sm_aes128_state = SM_AES128_IDLE; 3536 log_info_key("csrk", setup->sm_local_csrk); 3537 if (setup->sm_key_distribution_send_set != 0u){ 3538 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3539 } else { 3540 // no keys to send, just continue 3541 if (IS_RESPONDER(connection->sm_role)){ 3542 if (sm_key_distribution_all_received()){ 3543 sm_key_distribution_handle_all_received(connection); 3544 sm_key_distribution_complete_responder(connection); 3545 } else { 3546 // slave -> receive master keys 3547 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3548 } 3549 } else { 3550 sm_key_distribution_complete_initiator(connection); 3551 } 3552 } 3553 sm_trigger_run(); 3554 } 3555 3556 #ifdef ENABLE_LE_PERIPHERAL 3557 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3558 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3559 sm_aes128_state = SM_AES128_IDLE; 3560 3561 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3562 if (connection == NULL) return; 3563 3564 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3565 log_info_key("ltk", setup->sm_ltk); 3566 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3567 sm_trigger_run(); 3568 } 3569 #endif 3570 3571 static void sm_handle_encryption_result_address_resolution(void *arg){ 3572 UNUSED(arg); 3573 sm_aes128_state = SM_AES128_IDLE; 3574 3575 // compare calulated address against connecting device 3576 uint8_t * hash = &sm_aes128_ciphertext[13]; 3577 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3578 log_info("LE Device Lookup: matched resolvable private address"); 3579 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3580 sm_trigger_run(); 3581 return; 3582 } 3583 // no match, try next 3584 sm_address_resolution_test++; 3585 sm_trigger_run(); 3586 } 3587 3588 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3589 UNUSED(arg); 3590 sm_aes128_state = SM_AES128_IDLE; 3591 3592 log_info_key("irk", sm_persistent_irk); 3593 dkg_state = DKG_CALC_DHK; 3594 sm_trigger_run(); 3595 } 3596 3597 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3598 UNUSED(arg); 3599 sm_aes128_state = SM_AES128_IDLE; 3600 3601 log_info_key("dhk", sm_persistent_dhk); 3602 dkg_state = DKG_READY; 3603 sm_trigger_run(); 3604 } 3605 3606 static void sm_handle_encryption_result_rau(void *arg){ 3607 UNUSED(arg); 3608 sm_aes128_state = SM_AES128_IDLE; 3609 3610 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3611 rau_state = RAU_IDLE; 3612 hci_le_random_address_set(sm_random_address); 3613 3614 sm_trigger_run(); 3615 } 3616 3617 static void sm_handle_random_result_rau(void * arg){ 3618 UNUSED(arg); 3619 // non-resolvable vs. resolvable 3620 switch (gap_random_adress_type){ 3621 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3622 // resolvable: use random as prand and calc address hash 3623 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3624 sm_random_address[0u] &= 0x3fu; 3625 sm_random_address[0u] |= 0x40u; 3626 rau_state = RAU_GET_ENC; 3627 break; 3628 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3629 default: 3630 // "The two most significant bits of the address shall be equal to ‘0’"" 3631 sm_random_address[0u] &= 0x3fu; 3632 rau_state = RAU_IDLE; 3633 hci_le_random_address_set(sm_random_address); 3634 break; 3635 } 3636 sm_trigger_run(); 3637 } 3638 3639 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3640 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3641 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3642 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3643 if (connection == NULL) return; 3644 3645 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3646 sm_trigger_run(); 3647 } 3648 3649 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3650 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3651 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3652 if (connection == NULL) return; 3653 3654 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3655 sm_trigger_run(); 3656 } 3657 #endif 3658 3659 static void sm_handle_random_result_ph2_random(void * arg){ 3660 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3661 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3662 if (connection == NULL) return; 3663 3664 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3665 sm_trigger_run(); 3666 } 3667 3668 static void sm_handle_random_result_ph2_tk(void * arg){ 3669 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3670 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3671 if (connection == NULL) return; 3672 3673 sm_reset_tk(); 3674 uint32_t tk; 3675 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3676 // map random to 0-999999 without speding much cycles on a modulus operation 3677 tk = little_endian_read_32(sm_random_data,0); 3678 tk = tk & 0xfffff; // 1048575 3679 if (tk >= 999999u){ 3680 tk = tk - 999999u; 3681 } 3682 } else { 3683 // override with pre-defined passkey 3684 tk = sm_fixed_passkey_in_display_role; 3685 } 3686 big_endian_store_32(setup->sm_tk, 12, tk); 3687 if (IS_RESPONDER(connection->sm_role)){ 3688 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3689 } else { 3690 if (setup->sm_use_secure_connections){ 3691 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3692 } else { 3693 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3694 sm_trigger_user_response(connection); 3695 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3696 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3697 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); 3698 } 3699 } 3700 } 3701 sm_trigger_run(); 3702 } 3703 3704 static void sm_handle_random_result_ph3_div(void * arg){ 3705 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3706 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3707 if (connection == NULL) return; 3708 3709 // use 16 bit from random value as div 3710 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3711 log_info_hex16("div", setup->sm_local_div); 3712 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3713 sm_trigger_run(); 3714 } 3715 3716 static void sm_handle_random_result_ph3_random(void * arg){ 3717 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3718 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3719 if (connection == NULL) return; 3720 3721 reverse_64(sm_random_data, setup->sm_local_rand); 3722 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3723 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3724 // no db for authenticated flag hack: store flag in bit 4 of LSB 3725 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3726 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3727 } 3728 static void sm_validate_er_ir(void){ 3729 // warn about default ER/IR 3730 bool warning = false; 3731 if (sm_ir_is_default()){ 3732 warning = true; 3733 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3734 } 3735 if (sm_er_is_default()){ 3736 warning = true; 3737 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3738 } 3739 if (warning) { 3740 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3741 } 3742 } 3743 3744 static void sm_handle_random_result_ir(void *arg){ 3745 sm_persistent_keys_random_active = false; 3746 if (arg != NULL){ 3747 // key generated, store in tlv 3748 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3749 log_info("Generated IR key. Store in TLV status: %d", status); 3750 UNUSED(status); 3751 } 3752 log_info_key("IR", sm_persistent_ir); 3753 dkg_state = DKG_CALC_IRK; 3754 3755 if (test_use_fixed_local_irk){ 3756 log_info_key("IRK", sm_persistent_irk); 3757 dkg_state = DKG_CALC_DHK; 3758 } 3759 3760 sm_trigger_run(); 3761 } 3762 3763 static void sm_handle_random_result_er(void *arg){ 3764 sm_persistent_keys_random_active = false; 3765 if (arg != NULL){ 3766 // key generated, store in tlv 3767 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3768 log_info("Generated ER key. Store in TLV status: %d", status); 3769 UNUSED(status); 3770 } 3771 log_info_key("ER", sm_persistent_er); 3772 3773 // try load ir 3774 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3775 if (key_size == 16){ 3776 // ok, let's continue 3777 log_info("IR from TLV"); 3778 sm_handle_random_result_ir( NULL ); 3779 } else { 3780 // invalid, generate new random one 3781 sm_persistent_keys_random_active = true; 3782 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3783 } 3784 } 3785 3786 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){ 3787 3788 // connection info 3789 sm_conn->sm_handle = con_handle; 3790 sm_conn->sm_role = role; 3791 sm_conn->sm_peer_addr_type = peer_addr_type; 3792 memcpy(sm_conn->sm_peer_address, peer_address, 6); 3793 3794 // security properties 3795 sm_conn->sm_connection_encrypted = 0; 3796 sm_conn->sm_connection_authenticated = 0; 3797 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3798 sm_conn->sm_le_db_index = -1; 3799 sm_conn->sm_reencryption_active = false; 3800 3801 // prepare CSRK lookup (does not involve setup) 3802 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3803 3804 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3805 } 3806 3807 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3808 static void sm_event_handle_classic_encryption_event(sm_connection_t * sm_conn, hci_con_handle_t con_handle){ 3809 // CTKD requires BR/EDR Secure Connection 3810 if (sm_conn->sm_connection_encrypted != 2) return; 3811 // prepare for pairing request 3812 if (IS_RESPONDER(sm_conn->sm_role)){ 3813 log_info("CTKD: SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST"); 3814 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3815 } else if (sm_conn->sm_pairing_requested){ 3816 // check if remote supports fixed channels 3817 bool defer = true; 3818 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 3819 if (hci_connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE){ 3820 // check if remote supports SMP over BR/EDR 3821 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 3822 log_info("CTKD: SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST"); 3823 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3824 } else { 3825 defer = false; 3826 } 3827 } else { 3828 // wait for fixed channel info 3829 log_info("CTKD: SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK"); 3830 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK; 3831 } 3832 if (defer){ 3833 hci_dedicated_bonding_defer_disconnect(con_handle, true); 3834 } 3835 } 3836 } 3837 #endif 3838 3839 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3840 3841 UNUSED(channel); // ok: there is no channel 3842 UNUSED(size); // ok: fixed format HCI events 3843 3844 sm_connection_t * sm_conn; 3845 hci_con_handle_t con_handle; 3846 uint8_t status; 3847 bd_addr_t addr; 3848 bd_addr_type_t addr_type; 3849 3850 switch (packet_type) { 3851 3852 case HCI_EVENT_PACKET: 3853 switch (hci_event_packet_get_type(packet)) { 3854 3855 case BTSTACK_EVENT_STATE: 3856 switch (btstack_event_state_get_state(packet)){ 3857 case HCI_STATE_WORKING: 3858 log_info("HCI Working!"); 3859 // setup IR/ER with TLV 3860 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3861 if (sm_tlv_impl != NULL){ 3862 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3863 if (key_size == 16){ 3864 // ok, let's continue 3865 log_info("ER from TLV"); 3866 sm_handle_random_result_er( NULL ); 3867 } else { 3868 // invalid, generate random one 3869 sm_persistent_keys_random_active = true; 3870 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3871 } 3872 } else { 3873 sm_validate_er_ir(); 3874 dkg_state = DKG_CALC_IRK; 3875 3876 if (test_use_fixed_local_irk){ 3877 log_info_key("IRK", sm_persistent_irk); 3878 dkg_state = DKG_CALC_DHK; 3879 } 3880 } 3881 3882 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3883 // trigger ECC key generation 3884 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3885 sm_ec_generate_new_key(); 3886 } 3887 #endif 3888 3889 // restart random address updates after power cycle 3890 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ 3891 gap_random_address_set(sm_random_address); 3892 } else { 3893 gap_random_address_set_mode(gap_random_adress_type); 3894 } 3895 break; 3896 3897 case HCI_STATE_OFF: 3898 case HCI_STATE_HALTING: 3899 log_info("SM: reset state"); 3900 // stop random address update 3901 gap_random_address_update_stop(); 3902 // reset state 3903 sm_state_reset(); 3904 break; 3905 3906 default: 3907 break; 3908 } 3909 break; 3910 3911 #ifdef ENABLE_CLASSIC 3912 case HCI_EVENT_CONNECTION_COMPLETE: 3913 // ignore if connection failed 3914 if (hci_event_connection_complete_get_status(packet)) return; 3915 3916 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3917 sm_conn = sm_get_connection_for_handle(con_handle); 3918 if (!sm_conn) break; 3919 3920 hci_event_connection_complete_get_bd_addr(packet, addr); 3921 sm_connection_init(sm_conn, 3922 con_handle, 3923 (uint8_t) gap_get_role(con_handle), 3924 BD_ADDR_TYPE_LE_PUBLIC, 3925 addr); 3926 // classic connection corresponds to public le address 3927 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3928 gap_local_bd_addr(sm_conn->sm_own_address); 3929 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3930 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3931 break; 3932 3933 #endif 3934 3935 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3936 case HCI_EVENT_ROLE_CHANGE: 3937 hci_event_role_change_get_bd_addr(packet, addr); 3938 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3939 if (sm_conn == NULL) break; 3940 sm_conn->sm_role = hci_event_role_change_get_role(packet); 3941 break; 3942 3943 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3944 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3945 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3946 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3947 if (sm_conn == NULL) break; 3948 sm_conn->sm_pairing_requested = true; 3949 break; 3950 #endif 3951 3952 case HCI_EVENT_META_GAP: 3953 switch (hci_event_gap_meta_get_subevent_code(packet)) { 3954 case GAP_SUBEVENT_LE_CONNECTION_COMPLETE: 3955 // ignore if connection failed 3956 if (gap_subevent_le_connection_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3957 3958 con_handle = gap_subevent_le_connection_complete_get_connection_handle(packet); 3959 sm_conn = sm_get_connection_for_handle(con_handle); 3960 if (!sm_conn) break; 3961 3962 // Get current peer address 3963 addr_type = gap_subevent_le_connection_complete_get_peer_address_type(packet); 3964 if (hci_is_le_identity_address_type(addr_type)){ 3965 addr_type = BD_ADDR_TYPE_LE_RANDOM; 3966 gap_subevent_le_connection_complete_get_peer_resolvable_private_address(packet, addr); 3967 } else { 3968 gap_subevent_le_connection_complete_get_peer_address(packet, addr); 3969 } 3970 sm_connection_init(sm_conn, 3971 con_handle, 3972 gap_subevent_le_connection_complete_get_role(packet), 3973 addr_type, 3974 addr); 3975 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3976 3977 // track our addr used for this connection and set state 3978 #ifdef ENABLE_LE_PERIPHERAL 3979 if (gap_subevent_le_connection_complete_get_role(packet) != 0){ 3980 // responder - use own address from advertisements 3981 #ifdef ENABLE_LE_EXTENDED_ADVERTISING 3982 if (hci_le_extended_advertising_supported()){ 3983 // cache local resolvable address 3984 // note: will be overwritten if random or private address was used in adv set by HCI_SUBEVENT_LE_ADVERTISING_SET_TERMINATED 3985 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_RANDOM; 3986 gap_subevent_le_connection_complete_get_local_resolvable_private_address(packet,sm_conn->sm_own_address); 3987 } else 3988 #endif 3989 { 3990 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3991 } 3992 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3993 } 3994 #endif 3995 #ifdef ENABLE_LE_CENTRAL 3996 if (gap_subevent_le_connection_complete_get_role(packet) == 0){ 3997 // initiator - use own address from create connection 3998 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3999 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4000 } 4001 #endif 4002 break; 4003 default: 4004 break; 4005 } 4006 break; 4007 case HCI_EVENT_LE_META: 4008 switch (hci_event_le_meta_get_subevent_code(packet)) { 4009 #ifdef ENABLE_LE_PERIPHERAL 4010 #ifdef ENABLE_LE_EXTENDED_ADVERTISING 4011 case HCI_SUBEVENT_LE_ADVERTISING_SET_TERMINATED: 4012 if (hci_subevent_le_advertising_set_terminated_get_status(packet) == ERROR_CODE_SUCCESS){ 4013 uint8_t advertising_handle = hci_subevent_le_advertising_set_terminated_get_advertising_handle(packet); 4014 con_handle = hci_subevent_le_advertising_set_terminated_get_connection_handle(packet); 4015 sm_conn = sm_get_connection_for_handle(con_handle); 4016 if (!sm_conn) break; 4017 4018 gap_le_get_own_advertising_set_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address, advertising_handle); 4019 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, 4020 bd_addr_to_str(sm_conn->sm_own_address), con_handle); 4021 } 4022 break; 4023 #endif 4024 #endif 4025 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 4026 con_handle = hci_subevent_le_long_term_key_request_get_connection_handle(packet); 4027 sm_conn = sm_get_connection_for_handle(con_handle); 4028 if (!sm_conn) break; 4029 4030 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 4031 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 4032 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 4033 break; 4034 } 4035 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 4036 // PH2 SEND LTK as we need to exchange keys in PH3 4037 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 4038 break; 4039 } 4040 4041 // store rand and ediv 4042 reverse_64(&packet[5], sm_conn->sm_local_rand); 4043 sm_conn->sm_local_ediv = hci_subevent_le_long_term_key_request_get_encryption_diversifier(packet); 4044 4045 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 4046 // potentially stored LTK is from the master 4047 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 4048 if (sm_reconstruct_ltk_without_le_device_db_entry){ 4049 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 4050 break; 4051 } 4052 // additionally check if remote is in LE Device DB if requested 4053 switch(sm_conn->sm_irk_lookup_state){ 4054 case IRK_LOOKUP_FAILED: 4055 log_info("LTK Request: device not in device db"); 4056 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 4057 break; 4058 case IRK_LOOKUP_SUCCEEDED: 4059 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 4060 break; 4061 default: 4062 // wait for irk look doen 4063 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 4064 break; 4065 } 4066 break; 4067 } 4068 4069 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4070 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 4071 #else 4072 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 4073 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 4074 #endif 4075 break; 4076 4077 default: 4078 break; 4079 } 4080 break; 4081 4082 case HCI_EVENT_ENCRYPTION_CHANGE: 4083 case HCI_EVENT_ENCRYPTION_CHANGE_V2: 4084 con_handle = hci_event_encryption_change_get_connection_handle(packet); 4085 sm_conn = sm_get_connection_for_handle(con_handle); 4086 if (!sm_conn) break; 4087 4088 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 4089 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 4090 sm_conn->sm_actual_encryption_key_size); 4091 log_info("event handler, state %u", sm_conn->sm_engine_state); 4092 4093 switch (sm_conn->sm_engine_state){ 4094 4095 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4096 // encryption change event concludes re-encryption for bonded devices (even if it fails) 4097 if (sm_conn->sm_connection_encrypted != 0u) { 4098 status = ERROR_CODE_SUCCESS; 4099 if (IS_RESPONDER(sm_conn->sm_role)){ 4100 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4101 } else { 4102 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4103 } 4104 } else { 4105 status = hci_event_encryption_change_get_status(packet); 4106 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 4107 // also, gap_reconnect_security_setup_active will return true 4108 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 4109 } 4110 4111 // emit re-encryption complete 4112 sm_reencryption_complete(sm_conn, status); 4113 4114 // notify client, if pairing was requested before 4115 if (sm_conn->sm_pairing_requested){ 4116 sm_conn->sm_pairing_requested = false; 4117 sm_pairing_complete(sm_conn, status, 0); 4118 } 4119 4120 sm_done_for_handle(sm_conn->sm_handle); 4121 break; 4122 4123 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4124 if (!sm_conn->sm_connection_encrypted) break; 4125 // handler for HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE 4126 // contains the same code for this state 4127 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 4128 if (IS_RESPONDER(sm_conn->sm_role)){ 4129 // slave 4130 if (sm_conn->sm_connection_sc){ 4131 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4132 } else { 4133 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); 4134 } 4135 } else { 4136 // master 4137 if (sm_key_distribution_all_received()){ 4138 // skip receiving keys as there are none 4139 sm_key_distribution_handle_all_received(sm_conn); 4140 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); 4141 } else { 4142 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4143 } 4144 } 4145 break; 4146 4147 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4148 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4149 sm_event_handle_classic_encryption_event(sm_conn, con_handle); 4150 break; 4151 #endif 4152 default: 4153 break; 4154 } 4155 break; 4156 4157 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 4158 con_handle = little_endian_read_16(packet, 3); 4159 sm_conn = sm_get_connection_for_handle(con_handle); 4160 if (!sm_conn) break; 4161 4162 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 4163 log_info("event handler, state %u", sm_conn->sm_engine_state); 4164 // continue if part of initial pairing 4165 switch (sm_conn->sm_engine_state){ 4166 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4167 if (IS_RESPONDER(sm_conn->sm_role)){ 4168 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4169 } else { 4170 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4171 } 4172 sm_done_for_handle(sm_conn->sm_handle); 4173 break; 4174 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4175 // handler for HCI_EVENT_ENCRYPTION_CHANGE 4176 // contains the same code for this state 4177 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 4178 if (IS_RESPONDER(sm_conn->sm_role)){ 4179 // slave 4180 if (sm_conn->sm_connection_sc){ 4181 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4182 } else { 4183 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); 4184 } 4185 } else { 4186 // master 4187 if (sm_key_distribution_all_received()){ 4188 // skip receiving keys as there are none 4189 sm_key_distribution_handle_all_received(sm_conn); 4190 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); 4191 } else { 4192 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4193 } 4194 } 4195 break; 4196 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4197 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4198 sm_event_handle_classic_encryption_event(sm_conn, con_handle); 4199 break; 4200 #endif 4201 default: 4202 break; 4203 } 4204 break; 4205 4206 4207 case HCI_EVENT_DISCONNECTION_COMPLETE: 4208 con_handle = little_endian_read_16(packet, 3); 4209 sm_done_for_handle(con_handle); 4210 sm_conn = sm_get_connection_for_handle(con_handle); 4211 if (!sm_conn) break; 4212 4213 // pairing failed, if it was ongoing 4214 switch (sm_conn->sm_engine_state){ 4215 case SM_GENERAL_IDLE: 4216 case SM_INITIATOR_CONNECTED: 4217 case SM_RESPONDER_IDLE: 4218 break; 4219 default: 4220 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 4221 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 4222 break; 4223 } 4224 4225 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 4226 sm_conn->sm_handle = 0; 4227 break; 4228 4229 case HCI_EVENT_COMMAND_COMPLETE: 4230 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 4231 // set local addr for le device db 4232 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 4233 le_device_db_set_local_bd_addr(addr); 4234 } 4235 break; 4236 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4237 case L2CAP_EVENT_INFORMATION_RESPONSE: 4238 con_handle = l2cap_event_information_response_get_con_handle(packet); 4239 sm_conn = sm_get_connection_for_handle(con_handle); 4240 if (!sm_conn) break; 4241 if (sm_conn->sm_engine_state == SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK){ 4242 // check if remote supports SMP over BR/EDR 4243 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 4244 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 4245 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 4246 } else { 4247 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4248 hci_dedicated_bonding_defer_disconnect(con_handle, false); 4249 } 4250 } 4251 break; 4252 #endif 4253 default: 4254 break; 4255 } 4256 break; 4257 default: 4258 break; 4259 } 4260 4261 sm_run(); 4262 } 4263 4264 static inline int sm_calc_actual_encryption_key_size(int other){ 4265 if (other < sm_min_encryption_key_size) return 0; 4266 if (other < sm_max_encryption_key_size) return other; 4267 return sm_max_encryption_key_size; 4268 } 4269 4270 4271 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4272 static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 4273 switch (method){ 4274 case JUST_WORKS: 4275 case NUMERIC_COMPARISON: 4276 return true; 4277 default: 4278 return false; 4279 } 4280 } 4281 // responder 4282 4283 static bool sm_passkey_used(stk_generation_method_t method){ 4284 switch (method){ 4285 case PK_RESP_INPUT: 4286 return true; 4287 default: 4288 return 0; 4289 } 4290 } 4291 4292 static bool sm_passkey_entry(stk_generation_method_t method){ 4293 switch (method){ 4294 case PK_RESP_INPUT: 4295 case PK_INIT_INPUT: 4296 case PK_BOTH_INPUT: 4297 return true; 4298 default: 4299 return false; 4300 } 4301 } 4302 4303 #endif 4304 4305 /** 4306 * @return ok 4307 */ 4308 static int sm_validate_stk_generation_method(void){ 4309 // check if STK generation method is acceptable by client 4310 switch (setup->sm_stk_generation_method){ 4311 case JUST_WORKS: 4312 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4313 case PK_RESP_INPUT: 4314 case PK_INIT_INPUT: 4315 case PK_BOTH_INPUT: 4316 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4317 case OOB: 4318 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4319 case NUMERIC_COMPARISON: 4320 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4321 default: 4322 return 0; 4323 } 4324 } 4325 4326 #ifdef ENABLE_LE_CENTRAL 4327 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4328 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4329 if (sm_sc_only_mode){ 4330 uint8_t auth_req = packet[1]; 4331 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4332 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4333 return; 4334 } 4335 } 4336 #else 4337 UNUSED(packet); 4338 #endif 4339 4340 int have_ltk; 4341 uint8_t ltk[16]; 4342 4343 // IRK complete? 4344 switch (sm_conn->sm_irk_lookup_state){ 4345 case IRK_LOOKUP_FAILED: 4346 // start pairing 4347 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4348 break; 4349 case IRK_LOOKUP_SUCCEEDED: 4350 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4351 have_ltk = !sm_is_null_key(ltk); 4352 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4353 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4354 // start re-encrypt if we have LTK and the connection is not already encrypted 4355 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4356 } else { 4357 // start pairing 4358 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4359 } 4360 break; 4361 default: 4362 // otherwise, store security request 4363 sm_conn->sm_security_request_received = true; 4364 break; 4365 } 4366 } 4367 #endif 4368 4369 static uint8_t sm_pdu_validate_and_get_opcode(uint8_t packet_type, const uint8_t *packet, uint16_t size){ 4370 4371 // size of complete sm_pdu used to validate input 4372 static const uint8_t sm_pdu_size[] = { 4373 0, // 0x00 invalid opcode 4374 7, // 0x01 pairing request 4375 7, // 0x02 pairing response 4376 17, // 0x03 pairing confirm 4377 17, // 0x04 pairing random 4378 2, // 0x05 pairing failed 4379 17, // 0x06 encryption information 4380 11, // 0x07 master identification 4381 17, // 0x08 identification information 4382 8, // 0x09 identify address information 4383 17, // 0x0a signing information 4384 2, // 0x0b security request 4385 65, // 0x0c pairing public key 4386 17, // 0x0d pairing dhk check 4387 2, // 0x0e keypress notification 4388 }; 4389 4390 if (packet_type != SM_DATA_PACKET) return 0; 4391 if (size == 0u) return 0; 4392 4393 uint8_t sm_pdu_code = packet[0]; 4394 4395 // validate pdu size 4396 if (sm_pdu_code >= sizeof(sm_pdu_size)) return 0; 4397 if (sm_pdu_size[sm_pdu_code] != size) return 0; 4398 4399 return sm_pdu_code; 4400 } 4401 4402 static void sm_pdu_handler(sm_connection_t *sm_conn, uint8_t sm_pdu_code, const uint8_t *packet) { 4403 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4404 4405 int err; 4406 uint8_t max_encryption_key_size; 4407 UNUSED(err); 4408 4409 switch (sm_conn->sm_engine_state){ 4410 4411 // a sm timeout requires a new physical connection 4412 case SM_GENERAL_TIMEOUT: 4413 return; 4414 4415 #ifdef ENABLE_LE_CENTRAL 4416 4417 // Initiator 4418 case SM_INITIATOR_CONNECTED: 4419 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4420 sm_pdu_received_in_wrong_state(sm_conn); 4421 break; 4422 } 4423 sm_initiator_connected_handle_security_request(sm_conn, packet); 4424 break; 4425 4426 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4427 // Core 5, Vol 3, Part H, 2.4.6: 4428 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4429 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4430 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4431 log_info("Ignoring Security Request"); 4432 break; 4433 } 4434 4435 // all other pdus are incorrect 4436 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4437 sm_pdu_received_in_wrong_state(sm_conn); 4438 break; 4439 } 4440 4441 // store pairing request 4442 (void)memcpy(&setup->sm_s_pres, packet, 4443 sizeof(sm_pairing_packet_t)); 4444 4445 // validate encryption key size 4446 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); 4447 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4448 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4449 break; 4450 } 4451 4452 err = sm_stk_generation_init(sm_conn); 4453 4454 #ifdef ENABLE_TESTING_SUPPORT 4455 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4456 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4457 err = test_pairing_failure; 4458 } 4459 #endif 4460 4461 if (err != 0){ 4462 sm_pairing_error(sm_conn, err); 4463 break; 4464 } 4465 4466 // generate random number first, if we need to show passkey 4467 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4468 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); 4469 break; 4470 } 4471 4472 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4473 if (setup->sm_use_secure_connections){ 4474 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4475 if (setup->sm_stk_generation_method == JUST_WORKS){ 4476 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4477 sm_trigger_user_response(sm_conn); 4478 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4479 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4480 } 4481 } else { 4482 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4483 } 4484 break; 4485 } 4486 #endif 4487 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4488 sm_trigger_user_response(sm_conn); 4489 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4490 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4491 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); 4492 } 4493 break; 4494 4495 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4496 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4497 sm_pdu_received_in_wrong_state(sm_conn); 4498 break; 4499 } 4500 4501 // store s_confirm 4502 reverse_128(&packet[1], setup->sm_peer_confirm); 4503 4504 // abort if s_confirm matches m_confirm 4505 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4506 sm_pdu_received_in_wrong_state(sm_conn); 4507 break; 4508 } 4509 4510 #ifdef ENABLE_TESTING_SUPPORT 4511 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4512 log_info("testing_support: reset confirm value"); 4513 memset(setup->sm_peer_confirm, 0, 16); 4514 } 4515 #endif 4516 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4517 break; 4518 4519 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4520 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4521 sm_pdu_received_in_wrong_state(sm_conn); 4522 break;; 4523 } 4524 4525 // received random value 4526 reverse_128(&packet[1], setup->sm_peer_random); 4527 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4528 break; 4529 4530 case SM_INITIATOR_PH4_HAS_LTK: 4531 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4532 // ignore Security Request, see SM_INITIATOR_PH1_W4_PAIRING_RESPONSE above 4533 if (sm_pdu_code != SM_CODE_SECURITY_REQUEST){ 4534 sm_pdu_received_in_wrong_state(sm_conn); 4535 } 4536 break; 4537 #endif 4538 4539 #ifdef ENABLE_LE_PERIPHERAL 4540 // Responder 4541 case SM_RESPONDER_IDLE: 4542 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4543 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4544 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4545 sm_pdu_received_in_wrong_state(sm_conn); 4546 break;; 4547 } 4548 4549 // store pairing request 4550 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4551 4552 // validation encryption key size 4553 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); 4554 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4555 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4556 break; 4557 } 4558 4559 // check if IRK completed 4560 switch (sm_conn->sm_irk_lookup_state){ 4561 case IRK_LOOKUP_SUCCEEDED: 4562 case IRK_LOOKUP_FAILED: 4563 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4564 break; 4565 default: 4566 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4567 break; 4568 } 4569 break; 4570 #endif 4571 4572 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4573 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4574 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4575 sm_pdu_received_in_wrong_state(sm_conn); 4576 break; 4577 } 4578 4579 // store public key for DH Key calculation 4580 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4581 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4582 4583 // CVE-2020-26558: abort pairing if remote uses the same public key 4584 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4585 log_info("Remote PK matches ours"); 4586 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4587 break; 4588 } 4589 4590 // validate public key 4591 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4592 if (err != 0){ 4593 log_info("sm: peer public key invalid %x", err); 4594 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4595 break; 4596 } 4597 4598 // start calculating dhkey 4599 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); 4600 4601 4602 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4603 if (IS_RESPONDER(sm_conn->sm_role)){ 4604 // responder 4605 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4606 } else { 4607 // initiator 4608 // stk generation method 4609 // passkey entry: notify app to show passkey or to request passkey 4610 switch (setup->sm_stk_generation_method){ 4611 case JUST_WORKS: 4612 case NUMERIC_COMPARISON: 4613 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4614 break; 4615 case PK_RESP_INPUT: 4616 sm_sc_start_calculating_local_confirm(sm_conn); 4617 break; 4618 case PK_INIT_INPUT: 4619 case PK_BOTH_INPUT: 4620 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4621 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4622 break; 4623 } 4624 sm_sc_start_calculating_local_confirm(sm_conn); 4625 break; 4626 case OOB: 4627 if (setup->sm_have_oob_data){ 4628 // if we have received rb & cb, verify Cb = f4(PKb, PKb, rb, 0) 4629 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4630 } else { 4631 // otherwise, generate our nonce 4632 sm_sc_generate_nx_for_send_random(sm_conn); 4633 } 4634 break; 4635 default: 4636 btstack_assert(false); 4637 break; 4638 } 4639 } 4640 break; 4641 4642 case SM_SC_W4_CONFIRMATION: 4643 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4644 sm_pdu_received_in_wrong_state(sm_conn); 4645 break; 4646 } 4647 // received confirm value 4648 reverse_128(&packet[1], setup->sm_peer_confirm); 4649 4650 #ifdef ENABLE_TESTING_SUPPORT 4651 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4652 log_info("testing_support: reset confirm value"); 4653 memset(setup->sm_peer_confirm, 0, 16); 4654 } 4655 #endif 4656 if (IS_RESPONDER(sm_conn->sm_role)){ 4657 // responder 4658 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4659 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4660 // still waiting for passkey 4661 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4662 break; 4663 } 4664 } 4665 sm_sc_start_calculating_local_confirm(sm_conn); 4666 } else { 4667 // initiator 4668 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4669 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); 4670 } else { 4671 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4672 } 4673 } 4674 break; 4675 4676 case SM_SC_W4_PAIRING_RANDOM: 4677 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4678 sm_pdu_received_in_wrong_state(sm_conn); 4679 break; 4680 } 4681 4682 // received random value 4683 reverse_128(&packet[1], setup->sm_peer_nonce); 4684 4685 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4686 // only check for JUST WORK/NC in initiator role OR passkey entry 4687 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4688 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4689 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4690 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4691 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4692 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4693 break; 4694 } 4695 4696 // OOB 4697 if (setup->sm_stk_generation_method == OOB){ 4698 4699 // setup local random, set to zero if remote did not receive our data 4700 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4701 if (IS_RESPONDER(sm_conn->sm_role)) { 4702 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u) { 4703 log_info("Reset rb as A does not have OOB data"); 4704 memset(setup->sm_rb, 0, 16); 4705 } else { 4706 (void) memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4707 log_info("Use stored rb"); 4708 log_info_hexdump(setup->sm_rb, 16); 4709 } 4710 } else { 4711 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4712 log_info("Reset ra as B does not have OOB data"); 4713 memset(setup->sm_ra, 0, 16); 4714 } else { 4715 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4716 log_info("Use stored ra"); 4717 log_info_hexdump(setup->sm_ra, 16); 4718 } 4719 } 4720 4721 if (IS_RESPONDER(sm_conn->sm_role)){ 4722 if (setup->sm_have_oob_data){ 4723 // if we have received ra & ca, verify Ca = f4(PKa, PKa, ra, 0) 4724 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4725 } else { 4726 // otherwise, generate our nonce 4727 sm_sc_generate_nx_for_send_random(sm_conn); 4728 } 4729 } else { 4730 // Confirm value already validated if received before, 4731 // move on to DHKey check 4732 sm_sc_prepare_dhkey_check(sm_conn); 4733 } 4734 break; 4735 } 4736 4737 // TODO: we only get here for Responder role with JW/NC 4738 sm_sc_state_after_receiving_random(sm_conn); 4739 break; 4740 4741 case SM_SC_W2_CALCULATE_G2: 4742 case SM_SC_W4_CALCULATE_G2: 4743 case SM_SC_W4_CALCULATE_DHKEY: 4744 case SM_SC_W2_CALCULATE_F5_SALT: 4745 case SM_SC_W4_CALCULATE_F5_SALT: 4746 case SM_SC_W2_CALCULATE_F5_MACKEY: 4747 case SM_SC_W4_CALCULATE_F5_MACKEY: 4748 case SM_SC_W2_CALCULATE_F5_LTK: 4749 case SM_SC_W4_CALCULATE_F5_LTK: 4750 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4751 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4752 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4753 case SM_SC_W4_USER_RESPONSE: 4754 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4755 sm_pdu_received_in_wrong_state(sm_conn); 4756 break; 4757 } 4758 // store DHKey Check 4759 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4760 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4761 4762 // have we been only waiting for dhkey check command? 4763 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4764 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4765 } 4766 break; 4767 #endif 4768 4769 #ifdef ENABLE_LE_PERIPHERAL 4770 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4771 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4772 sm_pdu_received_in_wrong_state(sm_conn); 4773 break; 4774 } 4775 4776 // received confirm value 4777 reverse_128(&packet[1], setup->sm_peer_confirm); 4778 4779 #ifdef ENABLE_TESTING_SUPPORT 4780 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4781 log_info("testing_support: reset confirm value"); 4782 memset(setup->sm_peer_confirm, 0, 16); 4783 } 4784 #endif 4785 // notify client to hide shown passkey 4786 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4787 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4788 } 4789 4790 // handle user cancel pairing? 4791 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4792 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4793 break; 4794 } 4795 4796 // wait for user action? 4797 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4798 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4799 break; 4800 } 4801 4802 // calculate and send local_confirm 4803 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); 4804 break; 4805 4806 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4807 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4808 sm_pdu_received_in_wrong_state(sm_conn); 4809 break;; 4810 } 4811 4812 // received random value 4813 reverse_128(&packet[1], setup->sm_peer_random); 4814 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4815 break; 4816 #endif 4817 4818 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4819 case SM_PH3_RECEIVE_KEYS: 4820 switch(sm_pdu_code){ 4821 case SM_CODE_ENCRYPTION_INFORMATION: 4822 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4823 reverse_128(&packet[1], setup->sm_peer_ltk); 4824 break; 4825 4826 case SM_CODE_MASTER_IDENTIFICATION: 4827 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4828 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4829 reverse_64(&packet[3], setup->sm_peer_rand); 4830 break; 4831 4832 case SM_CODE_IDENTITY_INFORMATION: 4833 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4834 reverse_128(&packet[1], setup->sm_peer_irk); 4835 break; 4836 4837 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4838 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4839 setup->sm_peer_addr_type = packet[1]; 4840 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4841 break; 4842 4843 case SM_CODE_SIGNING_INFORMATION: 4844 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4845 reverse_128(&packet[1], setup->sm_peer_csrk); 4846 break; 4847 default: 4848 // Unexpected PDU 4849 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4850 break; 4851 } 4852 // done with key distribution? 4853 if (sm_key_distribution_all_received()){ 4854 4855 sm_key_distribution_handle_all_received(sm_conn); 4856 4857 if (IS_RESPONDER(sm_conn->sm_role)){ 4858 sm_key_distribution_complete_responder(sm_conn); 4859 } else { 4860 if (setup->sm_use_secure_connections){ 4861 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4862 } else { 4863 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); 4864 } 4865 } 4866 } 4867 break; 4868 4869 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4870 4871 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 4872 // GAP/DM/LEP/BI-02-C - reject CTKD if P-192 encryption is used 4873 if (sm_pdu_code == SM_CODE_PAIRING_REQUEST){ 4874 sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); 4875 } 4876 break; 4877 4878 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4879 4880 // dedicated bonding complete 4881 hci_dedicated_bonding_defer_disconnect(sm_conn->sm_handle, false); 4882 4883 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4884 sm_pdu_received_in_wrong_state(sm_conn); 4885 break; 4886 } 4887 // store pairing response 4888 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4889 4890 // validate encryption key size 4891 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); 4892 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4893 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4894 break; 4895 } 4896 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); 4897 // SC Only mandates 128 bit key size 4898 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4899 sm_conn->sm_actual_encryption_key_size = 0; 4900 } 4901 if (sm_conn->sm_actual_encryption_key_size == 0){ 4902 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4903 break; 4904 } 4905 4906 // prepare key exchange, LTK is derived locally 4907 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4908 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4909 4910 // skip receive if there are none 4911 if (sm_key_distribution_all_received()){ 4912 // distribute keys in run handles 'no keys to send' 4913 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4914 } else { 4915 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4916 } 4917 break; 4918 4919 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4920 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4921 sm_pdu_received_in_wrong_state(sm_conn); 4922 break; 4923 } 4924 4925 // store pairing request 4926 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4927 4928 // validate encryption key size 4929 max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); 4930 if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ 4931 sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); 4932 break; 4933 } 4934 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); 4935 // SC Only mandates 128 bit key size 4936 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4937 sm_conn->sm_actual_encryption_key_size = 0; 4938 } 4939 if (sm_conn->sm_actual_encryption_key_size == 0){ 4940 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4941 break; 4942 } 4943 // trigger response 4944 if (sm_ctkd_from_classic(sm_conn)){ 4945 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4946 } else { 4947 sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); 4948 } 4949 break; 4950 4951 case SM_BR_EDR_RECEIVE_KEYS: 4952 switch(sm_pdu_code){ 4953 case SM_CODE_IDENTITY_INFORMATION: 4954 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4955 reverse_128(&packet[1], setup->sm_peer_irk); 4956 break; 4957 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4958 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4959 setup->sm_peer_addr_type = packet[1]; 4960 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4961 break; 4962 case SM_CODE_SIGNING_INFORMATION: 4963 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4964 reverse_128(&packet[1], setup->sm_peer_csrk); 4965 break; 4966 default: 4967 // Unexpected PDU 4968 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4969 break; 4970 } 4971 4972 // all keys received 4973 if (sm_key_distribution_all_received()){ 4974 if (IS_RESPONDER(sm_conn->sm_role)){ 4975 // responder -> keys exchanged, derive LE LTK 4976 sm_ctkd_start_from_br_edr(sm_conn); 4977 } else { 4978 // initiator -> send our keys if any 4979 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4980 } 4981 } 4982 break; 4983 #endif 4984 4985 default: 4986 // Unexpected PDU 4987 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4988 sm_pdu_received_in_wrong_state(sm_conn); 4989 break; 4990 } 4991 4992 // try to send next pdu 4993 sm_trigger_run(); 4994 } 4995 4996 static void sm_channel_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4997 4998 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4999 sm_run(); 5000 } 5001 5002 uint8_t sm_pdu_code = sm_pdu_validate_and_get_opcode(packet_type, packet, size); 5003 if (sm_pdu_code == 0) return; 5004 5005 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5006 if (!sm_conn) return; 5007 5008 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 5009 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 5010 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 5011 sm_done_for_handle(con_handle); 5012 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 5013 return; 5014 } 5015 5016 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 5017 uint8_t buffer[5]; 5018 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 5019 buffer[1] = 3; 5020 little_endian_store_16(buffer, 2, con_handle); 5021 buffer[4] = packet[1]; 5022 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 5023 return; 5024 } 5025 5026 sm_pdu_handler(sm_conn, sm_pdu_code, packet); 5027 } 5028 5029 // Security Manager Client API 5030 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 5031 sm_get_oob_data = get_oob_data_callback; 5032 } 5033 5034 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)){ 5035 sm_get_sc_oob_data = get_sc_oob_data_callback; 5036 } 5037 5038 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)){ 5039 sm_get_ltk_callback = get_ltk_callback; 5040 } 5041 5042 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 5043 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 5044 } 5045 5046 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 5047 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 5048 } 5049 5050 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 5051 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 5052 } 5053 5054 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 5055 sm_min_encryption_key_size = min_size; 5056 sm_max_encryption_key_size = max_size; 5057 } 5058 5059 void sm_set_authentication_requirements(uint8_t auth_req){ 5060 #ifndef ENABLE_LE_SECURE_CONNECTIONS 5061 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 5062 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 5063 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 5064 } 5065 #endif 5066 sm_auth_req = auth_req; 5067 } 5068 5069 void sm_set_io_capabilities(io_capability_t io_capability){ 5070 sm_io_capabilities = io_capability; 5071 } 5072 5073 #ifdef ENABLE_LE_PERIPHERAL 5074 void sm_set_request_security(bool enable){ 5075 sm_slave_request_security = enable; 5076 } 5077 #endif 5078 5079 void sm_set_er(sm_key_t er){ 5080 (void)memcpy(sm_persistent_er, er, 16); 5081 } 5082 5083 void sm_set_ir(sm_key_t ir){ 5084 (void)memcpy(sm_persistent_ir, ir, 16); 5085 } 5086 5087 // Testing support only 5088 void sm_test_set_irk(sm_key_t irk){ 5089 (void)memcpy(sm_persistent_irk, irk, 16); 5090 dkg_state = DKG_CALC_DHK; 5091 test_use_fixed_local_irk = true; 5092 } 5093 5094 void sm_test_use_fixed_local_csrk(void){ 5095 test_use_fixed_local_csrk = true; 5096 } 5097 5098 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5099 static void sm_ec_generated(void * arg){ 5100 UNUSED(arg); 5101 ec_key_generation_state = EC_KEY_GENERATION_DONE; 5102 // trigger pairing if pending for ec key 5103 sm_trigger_run(); 5104 } 5105 static void sm_ec_generate_new_key(void) { 5106 log_info("sm: generate new ec key"); 5107 #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY 5108 // LE Secure Connections Debug Key 5109 const uint8_t debug_key_public[64] = { 5110 0x20, 0xb0, 0x03, 0xd2, 0xf2, 0x97, 0xbe, 0x2c, 0x5e, 0x2c, 0x83, 0xa7, 0xe9, 0xf9, 0xa5, 0xb9, 5111 0xef, 0xf4, 0x91, 0x11, 0xac, 0xf4, 0xfd, 0xdb, 0xcc, 0x03, 0x01, 0x48, 0x0e, 0x35, 0x9d, 0xe6, 5112 0xdc, 0x80, 0x9c, 0x49, 0x65, 0x2a, 0xeb, 0x6d, 0x63, 0x32, 0x9a, 0xbf, 0x5a, 0x52, 0x15, 0x5c, 5113 0x76, 0x63, 0x45, 0xc2, 0x8f, 0xed, 0x30, 0x24, 0x74, 0x1c, 0x8e, 0xd0, 0x15, 0x89, 0xd2, 0x8b 5114 }; 5115 const uint8_t debug_key_private[32] = { 5116 0x3f, 0x49, 0xf6, 0xd4, 0xa3, 0xc5, 0x5f, 0x38, 0x74, 0xc9, 0xb3, 0xe3, 0xd2, 0x10, 0x3f, 0x50, 5117 0x4a, 0xff, 0x60, 0x7b, 0xeb, 0x40, 0xb7, 0x99, 0x58, 0x99, 0xb8, 0xa6, 0xcd, 0x3c, 0x1a, 0xbd 5118 }; 5119 if (sm_sc_debug_keys_enabled) { 5120 memcpy(ec_q, debug_key_public, 64); 5121 btstack_crypto_ecc_p256_set_key(debug_key_public, debug_key_private); 5122 ec_key_generation_state = EC_KEY_GENERATION_DONE; 5123 } else 5124 #endif 5125 { 5126 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 5127 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 5128 } 5129 } 5130 #endif 5131 5132 #ifdef ENABLE_TESTING_SUPPORT 5133 void sm_test_set_pairing_failure(int reason){ 5134 test_pairing_failure = reason; 5135 } 5136 #endif 5137 5138 static void sm_state_reset(void) { 5139 #ifdef USE_CMAC_ENGINE 5140 sm_cmac_active = 0; 5141 #endif 5142 dkg_state = DKG_W4_WORKING; 5143 rau_state = RAU_IDLE; 5144 sm_aes128_state = SM_AES128_IDLE; 5145 sm_address_resolution_test = -1; // no private address to resolve yet 5146 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 5147 sm_address_resolution_general_queue = NULL; 5148 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 5149 sm_persistent_keys_random_active = false; 5150 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5151 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 5152 #endif 5153 } 5154 5155 void sm_init(void){ 5156 5157 if (sm_initialized) return; 5158 5159 // set default ER and IR values (should be unique - set by app or sm later using TLV) 5160 sm_er_ir_set_default(); 5161 5162 // defaults 5163 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 5164 | SM_STK_GENERATION_METHOD_OOB 5165 | SM_STK_GENERATION_METHOD_PASSKEY 5166 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 5167 5168 sm_max_encryption_key_size = 16; 5169 sm_min_encryption_key_size = 7; 5170 5171 sm_fixed_passkey_in_display_role = 0xffffffffU; 5172 sm_reconstruct_ltk_without_le_device_db_entry = true; 5173 5174 gap_random_adress_update_period = 15 * 60 * 1000L; 5175 5176 test_use_fixed_local_csrk = false; 5177 5178 // other 5179 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 5180 5181 // register for HCI Events 5182 hci_event_callback_registration.callback = &sm_event_packet_handler; 5183 hci_add_event_handler(&hci_event_callback_registration); 5184 5185 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 5186 // register for L2CAP events 5187 l2cap_event_callback_registration.callback = &sm_event_packet_handler; 5188 l2cap_add_event_handler(&l2cap_event_callback_registration); 5189 #endif 5190 5191 // 5192 btstack_crypto_init(); 5193 5194 // init le_device_db 5195 le_device_db_init(); 5196 5197 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 5198 l2cap_register_fixed_channel(sm_channel_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 5199 #ifdef ENABLE_CLASSIC 5200 l2cap_register_fixed_channel(sm_channel_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); 5201 #endif 5202 5203 // state 5204 sm_state_reset(); 5205 5206 sm_initialized = true; 5207 } 5208 5209 void sm_deinit(void){ 5210 sm_initialized = false; 5211 btstack_run_loop_remove_timer(&sm_run_timer); 5212 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) 5213 sm_sc_debug_keys_enabled = false; 5214 #endif 5215 } 5216 5217 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 5218 sm_fixed_passkey_in_display_role = passkey; 5219 } 5220 5221 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 5222 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 5223 } 5224 5225 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 5226 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 5227 if (!hci_con) return NULL; 5228 return &hci_con->sm_connection; 5229 } 5230 5231 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk){ 5232 hci_connection_t * hci_con = hci_connection_for_handle(connection->sm_handle); 5233 btstack_assert(hci_con != NULL); 5234 memcpy(hci_con->link_key, ltk, 16); 5235 hci_con->link_key_type = COMBINATION_KEY; 5236 } 5237 5238 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 5239 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 5240 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 5241 if (!hci_con) return NULL; 5242 return &hci_con->sm_connection; 5243 } 5244 #endif 5245 5246 // @deprecated: map onto sm_request_pairing 5247 void sm_send_security_request(hci_con_handle_t con_handle){ 5248 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5249 if (!sm_conn) return; 5250 if (!IS_RESPONDER(sm_conn->sm_role)) return; 5251 sm_request_pairing(con_handle); 5252 } 5253 5254 // request pairing 5255 void sm_request_pairing(hci_con_handle_t con_handle){ 5256 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5257 if (!sm_conn) return; // wrong connection 5258 5259 bool have_ltk; 5260 uint8_t ltk[16]; 5261 bool auth_required; 5262 int authenticated; 5263 bool trigger_reencryption; 5264 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 5265 if (IS_RESPONDER(sm_conn->sm_role)){ 5266 switch (sm_conn->sm_engine_state){ 5267 case SM_GENERAL_IDLE: 5268 case SM_RESPONDER_IDLE: 5269 switch (sm_conn->sm_irk_lookup_state){ 5270 case IRK_LOOKUP_SUCCEEDED: 5271 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 5272 have_ltk = !sm_is_null_key(ltk); 5273 log_info("have ltk %u", have_ltk); 5274 if (have_ltk){ 5275 sm_conn->sm_pairing_requested = true; 5276 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5277 sm_reencryption_started(sm_conn); 5278 break; 5279 } 5280 /* fall through */ 5281 5282 case IRK_LOOKUP_FAILED: 5283 sm_conn->sm_pairing_requested = true; 5284 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5285 sm_pairing_started(sm_conn); 5286 break; 5287 default: 5288 log_info("irk lookup pending"); 5289 sm_conn->sm_pairing_requested = true; 5290 break; 5291 } 5292 break; 5293 default: 5294 break; 5295 } 5296 } else { 5297 // used as a trigger to start central/master/initiator security procedures 5298 switch (sm_conn->sm_engine_state){ 5299 case SM_INITIATOR_CONNECTED: 5300 switch (sm_conn->sm_irk_lookup_state){ 5301 case IRK_LOOKUP_SUCCEEDED: 5302 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); 5303 have_ltk = !sm_is_null_key(ltk); 5304 auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; 5305 // re-encrypt is sufficient if we have ltk and that is either already authenticated or we don't require authentication 5306 trigger_reencryption = have_ltk && ((authenticated != 0) || (auth_required == false)); 5307 log_info("have ltk %u, authenticated %u, auth required %u => reencrypt %u", have_ltk, authenticated, auth_required, trigger_reencryption); 5308 if (trigger_reencryption){ 5309 sm_conn->sm_pairing_requested = true; 5310 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 5311 break; 5312 } 5313 /* fall through */ 5314 5315 case IRK_LOOKUP_FAILED: 5316 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5317 break; 5318 default: 5319 log_info("irk lookup pending"); 5320 sm_conn->sm_pairing_requested = true; 5321 break; 5322 } 5323 break; 5324 case SM_GENERAL_REENCRYPTION_FAILED: 5325 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5326 break; 5327 case SM_GENERAL_IDLE: 5328 sm_conn->sm_pairing_requested = true; 5329 break; 5330 default: 5331 break; 5332 } 5333 } 5334 sm_trigger_run(); 5335 } 5336 5337 // called by client app on authorization request 5338 void sm_authorization_decline(hci_con_handle_t con_handle){ 5339 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5340 if (!sm_conn) return; // wrong connection 5341 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 5342 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 5343 } 5344 5345 void sm_authorization_grant(hci_con_handle_t con_handle){ 5346 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5347 if (!sm_conn) return; // wrong connection 5348 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 5349 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 5350 } 5351 5352 // GAP Bonding API 5353 5354 void sm_bonding_decline(hci_con_handle_t con_handle){ 5355 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5356 if (!sm_conn) return; // wrong connection 5357 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 5358 log_info("decline, state %u", sm_conn->sm_engine_state); 5359 switch(sm_conn->sm_engine_state){ 5360 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5361 case SM_SC_W4_USER_RESPONSE: 5362 case SM_SC_W4_CONFIRMATION: 5363 case SM_SC_W4_PUBLIC_KEY_COMMAND: 5364 #endif 5365 case SM_PH1_W4_USER_RESPONSE: 5366 switch (setup->sm_stk_generation_method){ 5367 case PK_RESP_INPUT: 5368 case PK_INIT_INPUT: 5369 case PK_BOTH_INPUT: 5370 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 5371 break; 5372 case NUMERIC_COMPARISON: 5373 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 5374 break; 5375 case JUST_WORKS: 5376 case OOB: 5377 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 5378 break; 5379 default: 5380 btstack_assert(false); 5381 break; 5382 } 5383 break; 5384 default: 5385 break; 5386 } 5387 sm_trigger_run(); 5388 } 5389 5390 void sm_just_works_confirm(hci_con_handle_t con_handle){ 5391 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5392 if (!sm_conn) return; // wrong connection 5393 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 5394 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5395 if (setup->sm_use_secure_connections){ 5396 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 5397 } else { 5398 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); 5399 } 5400 } 5401 5402 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5403 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5404 sm_sc_prepare_dhkey_check(sm_conn); 5405 } 5406 #endif 5407 5408 sm_trigger_run(); 5409 } 5410 5411 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5412 // for now, it's the same 5413 sm_just_works_confirm(con_handle); 5414 } 5415 5416 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5417 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5418 if (!sm_conn) return; // wrong connection 5419 sm_reset_tk(); 5420 big_endian_store_32(setup->sm_tk, 12, passkey); 5421 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5422 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5423 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); 5424 } 5425 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5426 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5427 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5428 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5429 sm_sc_start_calculating_local_confirm(sm_conn); 5430 } 5431 #endif 5432 sm_trigger_run(); 5433 } 5434 5435 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5436 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5437 if (!sm_conn) return; // wrong connection 5438 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5439 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5440 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5441 switch (action){ 5442 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5443 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5444 flags |= (1u << action); 5445 break; 5446 case SM_KEYPRESS_PASSKEY_CLEARED: 5447 // clear counter, keypress & erased flags + set passkey cleared 5448 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5449 break; 5450 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5451 if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)) != 0u){ 5452 // erase actions queued 5453 num_actions--; 5454 if (num_actions == 0u){ 5455 // clear counter, keypress & erased flags 5456 flags &= 0x19u; 5457 } 5458 break; 5459 } 5460 num_actions++; 5461 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5462 break; 5463 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5464 if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)) != 0u){ 5465 // enter 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_ERASED); 5475 break; 5476 default: 5477 break; 5478 } 5479 setup->sm_keypress_notification = (num_actions << 5) | flags; 5480 sm_trigger_run(); 5481 } 5482 5483 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5484 static void sm_handle_random_result_oob(void * arg){ 5485 UNUSED(arg); 5486 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5487 sm_trigger_run(); 5488 } 5489 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5490 5491 static btstack_crypto_random_t sm_crypto_random_oob_request; 5492 5493 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5494 sm_sc_oob_callback = callback; 5495 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5496 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5497 return 0; 5498 } 5499 #endif 5500 5501 /** 5502 * @brief Get Identity Resolving state 5503 * @param con_handle 5504 * @return irk_lookup_state_t 5505 */ 5506 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5507 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5508 if (!sm_conn) return IRK_LOOKUP_IDLE; 5509 return sm_conn->sm_irk_lookup_state; 5510 } 5511 5512 /** 5513 * @brief Identify device in LE Device DB 5514 * @param handle 5515 * @return index from le_device_db or -1 if not found/identified 5516 */ 5517 int sm_le_device_index(hci_con_handle_t con_handle ){ 5518 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5519 if (!sm_conn) return -1; 5520 return sm_conn->sm_le_db_index; 5521 } 5522 5523 uint8_t sm_get_ltk(hci_con_handle_t con_handle, sm_key_t ltk){ 5524 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 5525 if (hci_connection == NULL){ 5526 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 5527 } 5528 if (hci_connection->link_key_type == INVALID_LINK_KEY){ 5529 return ERROR_CODE_PIN_OR_KEY_MISSING; 5530 } 5531 memcpy(ltk, hci_connection->link_key, 16); 5532 return ERROR_CODE_SUCCESS; 5533 } 5534 5535 static int gap_random_address_type_requires_updates(void){ 5536 switch (gap_random_adress_type){ 5537 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5538 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5539 return 0; 5540 default: 5541 return 1; 5542 } 5543 } 5544 5545 static uint8_t own_address_type(void){ 5546 switch (gap_random_adress_type){ 5547 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5548 return BD_ADDR_TYPE_LE_PUBLIC; 5549 default: 5550 return BD_ADDR_TYPE_LE_RANDOM; 5551 } 5552 } 5553 5554 // GAP LE API 5555 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5556 gap_random_address_update_stop(); 5557 gap_random_adress_type = random_address_type; 5558 hci_le_set_own_address_type(own_address_type()); 5559 if (!gap_random_address_type_requires_updates()) return; 5560 gap_random_address_update_start(); 5561 gap_random_address_trigger(); 5562 } 5563 5564 gap_random_address_type_t gap_random_address_get_mode(void){ 5565 return gap_random_adress_type; 5566 } 5567 5568 void gap_random_address_set_update_period(int period_ms){ 5569 gap_random_adress_update_period = period_ms; 5570 if (!gap_random_address_type_requires_updates()) return; 5571 gap_random_address_update_stop(); 5572 gap_random_address_update_start(); 5573 } 5574 5575 void gap_random_address_set(const bd_addr_t addr){ 5576 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5577 (void)memcpy(sm_random_address, addr, 6); 5578 // assert msb bits are set to '11' 5579 sm_random_address[0] |= 0xc0; 5580 hci_le_random_address_set(sm_random_address); 5581 } 5582 5583 #ifdef ENABLE_LE_PERIPHERAL 5584 /* 5585 * @brief Set Advertisement Paramters 5586 * @param adv_int_min 5587 * @param adv_int_max 5588 * @param adv_type 5589 * @param direct_address_type 5590 * @param direct_address 5591 * @param channel_map 5592 * @param filter_policy 5593 * 5594 * @note own_address_type is used from gap_random_address_set_mode 5595 */ 5596 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5597 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5598 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5599 direct_address_typ, direct_address, channel_map, filter_policy); 5600 } 5601 #endif 5602 5603 bool gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5604 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5605 // wrong connection 5606 if (!sm_conn) return false; 5607 // already encrypted 5608 if (sm_conn->sm_connection_encrypted) return false; 5609 // irk status? 5610 switch(sm_conn->sm_irk_lookup_state){ 5611 case IRK_LOOKUP_FAILED: 5612 // done, cannot setup encryption 5613 return false; 5614 case IRK_LOOKUP_SUCCEEDED: 5615 break; 5616 default: 5617 // IR Lookup pending 5618 return true; 5619 } 5620 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5621 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return false; 5622 if (sm_conn->sm_role != 0){ 5623 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5624 } else { 5625 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5626 } 5627 } 5628 5629 void sm_set_secure_connections_only_mode(bool enable){ 5630 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5631 sm_sc_only_mode = enable; 5632 #else 5633 // SC Only mode not possible without support for SC 5634 btstack_assert(enable == false); 5635 #endif 5636 } 5637 5638 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) 5639 void sm_test_enable_secure_connections_debug_keys(void) { 5640 log_info("Enable LE Secure Connection Debug Keys for testing"); 5641 sm_sc_debug_keys_enabled = true; 5642 // set debug key 5643 sm_ec_generate_new_key(); 5644 } 5645 #endif 5646 5647 const uint8_t * gap_get_persistent_irk(void){ 5648 return sm_persistent_irk; 5649 } 5650 5651 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5652 int index = sm_le_device_db_index_lookup(address_type, address); 5653 if (index >= 0){ 5654 sm_remove_le_device_db_entry(index); 5655 } 5656 } 5657