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