1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 } random_address_update_t; 111 112 typedef enum { 113 CMAC_IDLE, 114 CMAC_CALC_SUBKEYS, 115 CMAC_W4_SUBKEYS, 116 CMAC_CALC_MI, 117 CMAC_W4_MI, 118 CMAC_CALC_MLAST, 119 CMAC_W4_MLAST 120 } cmac_state_t; 121 122 typedef enum { 123 JUST_WORKS, 124 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 125 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 126 PK_BOTH_INPUT, // Only input on both, both input PK 127 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 128 OOB // OOB available on one (SC) or both sides (legacy) 129 } stk_generation_method_t; 130 131 typedef enum { 132 SM_USER_RESPONSE_IDLE, 133 SM_USER_RESPONSE_PENDING, 134 SM_USER_RESPONSE_CONFIRM, 135 SM_USER_RESPONSE_PASSKEY, 136 SM_USER_RESPONSE_DECLINE 137 } sm_user_response_t; 138 139 typedef enum { 140 SM_AES128_IDLE, 141 SM_AES128_ACTIVE 142 } sm_aes128_state_t; 143 144 typedef enum { 145 ADDRESS_RESOLUTION_IDLE, 146 ADDRESS_RESOLUTION_GENERAL, 147 ADDRESS_RESOLUTION_FOR_CONNECTION, 148 } address_resolution_mode_t; 149 150 typedef enum { 151 ADDRESS_RESOLUTION_SUCCEEDED, 152 ADDRESS_RESOLUTION_FAILED, 153 } address_resolution_event_t; 154 155 typedef enum { 156 EC_KEY_GENERATION_IDLE, 157 EC_KEY_GENERATION_ACTIVE, 158 EC_KEY_GENERATION_DONE, 159 } ec_key_generation_state_t; 160 161 typedef enum { 162 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 163 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 165 } sm_state_var_t; 166 167 typedef enum { 168 SM_SC_OOB_IDLE, 169 SM_SC_OOB_W4_RANDOM, 170 SM_SC_OOB_W2_CALC_CONFIRM, 171 SM_SC_OOB_W4_CONFIRM, 172 } sm_sc_oob_state_t; 173 174 typedef uint8_t sm_key24_t[3]; 175 typedef uint8_t sm_key56_t[7]; 176 typedef uint8_t sm_key256_t[32]; 177 178 // 179 // GLOBAL DATA 180 // 181 182 static bool sm_initialized; 183 184 static bool test_use_fixed_local_csrk; 185 static bool test_use_fixed_local_irk; 186 187 #ifdef ENABLE_TESTING_SUPPORT 188 static uint8_t test_pairing_failure; 189 #endif 190 191 // configuration 192 static uint8_t sm_accepted_stk_generation_methods; 193 static uint8_t sm_max_encryption_key_size; 194 static uint8_t sm_min_encryption_key_size; 195 static uint8_t sm_auth_req = 0; 196 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 197 static uint8_t sm_slave_request_security; 198 static uint32_t sm_fixed_passkey_in_display_role; 199 static bool sm_reconstruct_ltk_without_le_device_db_entry; 200 201 #ifdef ENABLE_LE_SECURE_CONNECTIONS 202 static bool sm_sc_only_mode; 203 static uint8_t sm_sc_oob_random[16]; 204 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 205 static sm_sc_oob_state_t sm_sc_oob_state; 206 #endif 207 208 209 static bool sm_persistent_keys_random_active; 210 static const btstack_tlv_t * sm_tlv_impl; 211 static void * sm_tlv_context; 212 213 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 214 static sm_key_t sm_persistent_er; 215 static sm_key_t sm_persistent_ir; 216 217 // derived from sm_persistent_ir 218 static sm_key_t sm_persistent_dhk; 219 static sm_key_t sm_persistent_irk; 220 static derived_key_generation_t dkg_state; 221 222 // derived from sm_persistent_er 223 // .. 224 225 // random address update 226 static random_address_update_t rau_state; 227 static bd_addr_t sm_random_address; 228 229 #ifdef USE_CMAC_ENGINE 230 // CMAC Calculation: General 231 static btstack_crypto_aes128_cmac_t sm_cmac_request; 232 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 233 static uint8_t sm_cmac_active; 234 static uint8_t sm_cmac_hash[16]; 235 #endif 236 237 // CMAC for ATT Signed Writes 238 #ifdef ENABLE_LE_SIGNED_WRITE 239 static uint16_t sm_cmac_signed_write_message_len; 240 static uint8_t sm_cmac_signed_write_header[3]; 241 static const uint8_t * sm_cmac_signed_write_message; 242 static uint8_t sm_cmac_signed_write_sign_counter[4]; 243 #endif 244 245 // CMAC for Secure Connection functions 246 #ifdef ENABLE_LE_SECURE_CONNECTIONS 247 static sm_connection_t * sm_cmac_connection; 248 static uint8_t sm_cmac_sc_buffer[80]; 249 #endif 250 251 // resolvable private address lookup / CSRK calculation 252 static int sm_address_resolution_test; 253 static int sm_address_resolution_ah_calculation_active; 254 static uint8_t sm_address_resolution_addr_type; 255 static bd_addr_t sm_address_resolution_address; 256 static void * sm_address_resolution_context; 257 static address_resolution_mode_t sm_address_resolution_mode; 258 static btstack_linked_list_t sm_address_resolution_general_queue; 259 260 // aes128 crypto engine. 261 static sm_aes128_state_t sm_aes128_state; 262 263 // crypto 264 static btstack_crypto_random_t sm_crypto_random_request; 265 static btstack_crypto_aes128_t sm_crypto_aes128_request; 266 #ifdef ENABLE_LE_SECURE_CONNECTIONS 267 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 268 #endif 269 270 // temp storage for random data 271 static uint8_t sm_random_data[8]; 272 static uint8_t sm_aes128_key[16]; 273 static uint8_t sm_aes128_plaintext[16]; 274 static uint8_t sm_aes128_ciphertext[16]; 275 276 // to receive hci events 277 static btstack_packet_callback_registration_t hci_event_callback_registration; 278 279 /* to dispatch sm event */ 280 static btstack_linked_list_t sm_event_handlers; 281 282 /* to schedule calls to sm_run */ 283 static btstack_timer_source_t sm_run_timer; 284 285 // LE Secure Connections 286 #ifdef ENABLE_LE_SECURE_CONNECTIONS 287 static ec_key_generation_state_t ec_key_generation_state; 288 static uint8_t ec_q[64]; 289 #endif 290 291 // 292 // Volume 3, Part H, Chapter 24 293 // "Security shall be initiated by the Security Manager in the device in the master role. 294 // The device in the slave role shall be the responding device." 295 // -> master := initiator, slave := responder 296 // 297 298 // data needed for security setup 299 typedef struct sm_setup_context { 300 301 btstack_timer_source_t sm_timeout; 302 303 // user response, (Phase 1 and/or 2) 304 uint8_t sm_user_response; 305 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 306 307 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 308 uint8_t sm_key_distribution_send_set; 309 uint8_t sm_key_distribution_sent_set; 310 uint8_t sm_key_distribution_expected_set; 311 uint8_t sm_key_distribution_received_set; 312 313 // Phase 2 (Pairing over SMP) 314 stk_generation_method_t sm_stk_generation_method; 315 sm_key_t sm_tk; 316 uint8_t sm_have_oob_data; 317 uint8_t sm_use_secure_connections; 318 319 sm_key_t sm_c1_t3_value; // c1 calculation 320 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 321 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 322 sm_key_t sm_local_random; 323 sm_key_t sm_local_confirm; 324 sm_key_t sm_peer_random; 325 sm_key_t sm_peer_confirm; 326 uint8_t sm_m_addr_type; // address and type can be removed 327 uint8_t sm_s_addr_type; // '' 328 bd_addr_t sm_m_address; // '' 329 bd_addr_t sm_s_address; // '' 330 sm_key_t sm_ltk; 331 332 uint8_t sm_state_vars; 333 #ifdef ENABLE_LE_SECURE_CONNECTIONS 334 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 335 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 336 sm_key_t sm_local_nonce; // might be combined with sm_local_random 337 uint8_t sm_dhkey[32]; 338 sm_key_t sm_peer_dhkey_check; 339 sm_key_t sm_local_dhkey_check; 340 sm_key_t sm_ra; 341 sm_key_t sm_rb; 342 sm_key_t sm_t; // used for f5 and h6 343 sm_key_t sm_mackey; 344 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 345 #endif 346 347 // Phase 3 348 349 // key distribution, we generate 350 uint16_t sm_local_y; 351 uint16_t sm_local_div; 352 uint16_t sm_local_ediv; 353 uint8_t sm_local_rand[8]; 354 sm_key_t sm_local_ltk; 355 sm_key_t sm_local_csrk; 356 sm_key_t sm_local_irk; 357 // sm_local_address/addr_type not needed 358 359 // key distribution, received from peer 360 uint16_t sm_peer_y; 361 uint16_t sm_peer_div; 362 uint16_t sm_peer_ediv; 363 uint8_t sm_peer_rand[8]; 364 sm_key_t sm_peer_ltk; 365 sm_key_t sm_peer_irk; 366 sm_key_t sm_peer_csrk; 367 uint8_t sm_peer_addr_type; 368 bd_addr_t sm_peer_address; 369 #ifdef ENABLE_LE_SIGNED_WRITE 370 int sm_le_device_index; 371 #endif 372 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 373 link_key_t sm_link_key; 374 link_key_type_t sm_link_key_type; 375 #endif 376 } sm_setup_context_t; 377 378 // 379 static sm_setup_context_t the_setup; 380 static sm_setup_context_t * setup = &the_setup; 381 382 // active connection - the one for which the_setup is used for 383 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 384 385 // @return 1 if oob data is available 386 // stores oob data in provided 16 byte buffer if not null 387 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 388 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); 389 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 390 391 static void sm_run(void); 392 static void sm_done_for_handle(hci_con_handle_t con_handle); 393 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 394 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 395 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 396 #endif 397 static inline int sm_calc_actual_encryption_key_size(int other); 398 static int sm_validate_stk_generation_method(void); 399 static void sm_handle_encryption_result_address_resolution(void *arg); 400 static void sm_handle_encryption_result_dkg_dhk(void *arg); 401 static void sm_handle_encryption_result_dkg_irk(void *arg); 402 static void sm_handle_encryption_result_enc_a(void *arg); 403 static void sm_handle_encryption_result_enc_b(void *arg); 404 static void sm_handle_encryption_result_enc_c(void *arg); 405 static void sm_handle_encryption_result_enc_csrk(void *arg); 406 static void sm_handle_encryption_result_enc_d(void * arg); 407 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 408 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 409 #ifdef ENABLE_LE_PERIPHERAL 410 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 411 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 412 #endif 413 static void sm_handle_encryption_result_enc_stk(void *arg); 414 static void sm_handle_encryption_result_rau(void *arg); 415 static void sm_handle_random_result_ph2_tk(void * arg); 416 static void sm_handle_random_result_rau(void * arg); 417 #ifdef ENABLE_LE_SECURE_CONNECTIONS 418 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)); 419 static void sm_ec_generate_new_key(void); 420 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 421 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 422 static int sm_passkey_entry(stk_generation_method_t method); 423 #endif 424 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 425 426 static void log_info_hex16(const char * name, uint16_t value){ 427 log_info("%-6s 0x%04x", name, value); 428 } 429 430 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 431 // return packet[0]; 432 // } 433 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 434 return packet[1]; 435 } 436 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 437 return packet[2]; 438 } 439 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 440 return packet[3]; 441 } 442 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 443 return packet[4]; 444 } 445 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 446 return packet[5]; 447 } 448 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 449 return packet[6]; 450 } 451 452 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 453 packet[0] = code; 454 } 455 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 456 packet[1] = io_capability; 457 } 458 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 459 packet[2] = oob_data_flag; 460 } 461 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 462 packet[3] = auth_req; 463 } 464 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 465 packet[4] = max_encryption_key_size; 466 } 467 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 468 packet[5] = initiator_key_distribution; 469 } 470 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 471 packet[6] = responder_key_distribution; 472 } 473 474 // @return 1 if all bytes are 0 475 static bool sm_is_null(uint8_t * data, int size){ 476 int i; 477 for (i=0; i < size ; i++){ 478 if (data[i] != 0) { 479 return false; 480 } 481 } 482 return true; 483 } 484 485 static bool sm_is_null_random(uint8_t random[8]){ 486 return sm_is_null(random, 8); 487 } 488 489 static bool sm_is_null_key(uint8_t * key){ 490 return sm_is_null(key, 16); 491 } 492 493 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 494 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 495 UNUSED(ts); 496 sm_run(); 497 } 498 static void sm_trigger_run(void){ 499 if (!sm_initialized) return; 500 (void)btstack_run_loop_remove_timer(&sm_run_timer); 501 btstack_run_loop_set_timer(&sm_run_timer, 0); 502 btstack_run_loop_add_timer(&sm_run_timer); 503 } 504 505 // Key utils 506 static void sm_reset_tk(void){ 507 int i; 508 for (i=0;i<16;i++){ 509 setup->sm_tk[i] = 0; 510 } 511 } 512 513 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 514 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 515 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 516 int i; 517 for (i = max_encryption_size ; i < 16 ; i++){ 518 key[15-i] = 0; 519 } 520 } 521 522 // ER / IR checks 523 static void sm_er_ir_set_default(void){ 524 int i; 525 for (i=0;i<16;i++){ 526 sm_persistent_er[i] = 0x30 + i; 527 sm_persistent_ir[i] = 0x90 + i; 528 } 529 } 530 531 static int sm_er_is_default(void){ 532 int i; 533 for (i=0;i<16;i++){ 534 if (sm_persistent_er[i] != (0x30+i)) return 0; 535 } 536 return 1; 537 } 538 539 static int sm_ir_is_default(void){ 540 int i; 541 for (i=0;i<16;i++){ 542 if (sm_persistent_ir[i] != (0x90+i)) return 0; 543 } 544 return 1; 545 } 546 547 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 548 UNUSED(channel); 549 550 // log event 551 hci_dump_packet(packet_type, 1, packet, size); 552 // dispatch to all event handlers 553 btstack_linked_list_iterator_t it; 554 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 555 while (btstack_linked_list_iterator_has_next(&it)){ 556 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 557 entry->callback(packet_type, 0, packet, size); 558 } 559 } 560 561 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){ 562 event[0] = type; 563 event[1] = event_size - 2; 564 little_endian_store_16(event, 2, con_handle); 565 event[4] = addr_type; 566 reverse_bd_addr(address, &event[5]); 567 } 568 569 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 570 uint8_t event[11]; 571 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 572 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 573 } 574 575 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 576 uint8_t event[15]; 577 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 578 little_endian_store_32(event, 11, passkey); 579 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 580 } 581 582 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){ 583 // fetch addr and addr type from db, only called for valid entries 584 bd_addr_t identity_address; 585 int identity_address_type; 586 le_device_db_info(index, &identity_address_type, identity_address, NULL); 587 588 uint8_t event[20]; 589 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 590 event[11] = identity_address_type; 591 reverse_bd_addr(identity_address, &event[12]); 592 little_endian_store_16(event, 18, index); 593 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 594 } 595 596 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){ 597 uint8_t event[12]; 598 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 599 event[11] = status; 600 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 601 } 602 603 604 static void sm_reencryption_started(sm_connection_t * sm_conn){ 605 606 if (sm_conn->sm_reencryption_active) return; 607 608 sm_conn->sm_reencryption_active = true; 609 610 int identity_addr_type; 611 bd_addr_t identity_addr; 612 if (sm_conn->sm_le_db_index >= 0){ 613 // fetch addr and addr type from db, only called for valid entries 614 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 615 } else { 616 // for legacy pairing with LTK re-construction, use current peer addr 617 identity_addr_type = sm_conn->sm_peer_addr_type; 618 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 619 } 620 621 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 622 } 623 624 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 625 626 if (!sm_conn->sm_reencryption_active) return; 627 628 sm_conn->sm_reencryption_active = false; 629 630 int identity_addr_type; 631 bd_addr_t identity_addr; 632 if (sm_conn->sm_le_db_index >= 0){ 633 // fetch addr and addr type from db, only called for valid entries 634 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 635 } else { 636 // for legacy pairing with LTK re-construction, use current peer addr 637 identity_addr_type = sm_conn->sm_peer_addr_type; 638 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 639 } 640 641 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 642 } 643 644 static void sm_pairing_started(sm_connection_t * sm_conn){ 645 646 if (sm_conn->sm_pairing_active) return; 647 648 sm_conn->sm_pairing_active = true; 649 650 uint8_t event[11]; 651 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 652 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 653 } 654 655 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 656 657 if (!sm_conn->sm_pairing_active) return; 658 659 sm_conn->sm_pairing_active = false; 660 661 uint8_t event[13]; 662 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 663 event[11] = status; 664 event[12] = reason; 665 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 666 } 667 668 // SMP Timeout implementation 669 670 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 671 // the Security Manager Timer shall be reset and started. 672 // 673 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 674 // 675 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 676 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 677 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 678 // established. 679 680 static void sm_timeout_handler(btstack_timer_source_t * timer){ 681 log_info("SM timeout"); 682 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 683 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 684 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 685 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 686 sm_done_for_handle(sm_conn->sm_handle); 687 688 // trigger handling of next ready connection 689 sm_run(); 690 } 691 static void sm_timeout_start(sm_connection_t * sm_conn){ 692 btstack_run_loop_remove_timer(&setup->sm_timeout); 693 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 694 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 695 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 696 btstack_run_loop_add_timer(&setup->sm_timeout); 697 } 698 static void sm_timeout_stop(void){ 699 btstack_run_loop_remove_timer(&setup->sm_timeout); 700 } 701 static void sm_timeout_reset(sm_connection_t * sm_conn){ 702 sm_timeout_stop(); 703 sm_timeout_start(sm_conn); 704 } 705 706 // end of sm timeout 707 708 // GAP Random Address updates 709 static gap_random_address_type_t gap_random_adress_type; 710 static btstack_timer_source_t gap_random_address_update_timer; 711 static uint32_t gap_random_adress_update_period; 712 713 static void gap_random_address_trigger(void){ 714 log_info("gap_random_address_trigger, state %u", rau_state); 715 if (rau_state != RAU_IDLE) return; 716 rau_state = RAU_GET_RANDOM; 717 sm_trigger_run(); 718 } 719 720 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 721 UNUSED(timer); 722 723 log_info("GAP Random Address Update due"); 724 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 725 btstack_run_loop_add_timer(&gap_random_address_update_timer); 726 gap_random_address_trigger(); 727 } 728 729 static void gap_random_address_update_start(void){ 730 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 731 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 732 btstack_run_loop_add_timer(&gap_random_address_update_timer); 733 } 734 735 static void gap_random_address_update_stop(void){ 736 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 737 } 738 739 // ah(k,r) helper 740 // r = padding || r 741 // r - 24 bit value 742 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 743 // r'= padding || r 744 memset(r_prime, 0, 16); 745 (void)memcpy(&r_prime[13], r, 3); 746 } 747 748 // d1 helper 749 // d' = padding || r || d 750 // d,r - 16 bit values 751 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 752 // d'= padding || r || d 753 memset(d1_prime, 0, 16); 754 big_endian_store_16(d1_prime, 12, r); 755 big_endian_store_16(d1_prime, 14, d); 756 } 757 758 // calculate arguments for first AES128 operation in C1 function 759 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){ 760 761 // p1 = pres || preq || rat’ || iat’ 762 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 763 // cant octet of pres becomes the most significant octet of p1. 764 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 765 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 766 // p1 is 0x05000800000302070710000001010001." 767 768 sm_key_t p1; 769 reverse_56(pres, &p1[0]); 770 reverse_56(preq, &p1[7]); 771 p1[14] = rat; 772 p1[15] = iat; 773 log_info_key("p1", p1); 774 log_info_key("r", r); 775 776 // t1 = r xor p1 777 int i; 778 for (i=0;i<16;i++){ 779 t1[i] = r[i] ^ p1[i]; 780 } 781 log_info_key("t1", t1); 782 } 783 784 // calculate arguments for second AES128 operation in C1 function 785 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 786 // p2 = padding || ia || ra 787 // "The least significant octet of ra becomes the least significant octet of p2 and 788 // the most significant octet of padding becomes the most significant octet of p2. 789 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 790 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 791 792 sm_key_t p2; 793 memset(p2, 0, 16); 794 (void)memcpy(&p2[4], ia, 6); 795 (void)memcpy(&p2[10], ra, 6); 796 log_info_key("p2", p2); 797 798 // c1 = e(k, t2_xor_p2) 799 int i; 800 for (i=0;i<16;i++){ 801 t3[i] = t2[i] ^ p2[i]; 802 } 803 log_info_key("t3", t3); 804 } 805 806 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 807 log_info_key("r1", r1); 808 log_info_key("r2", r2); 809 (void)memcpy(&r_prime[8], &r2[8], 8); 810 (void)memcpy(&r_prime[0], &r1[8], 8); 811 } 812 813 814 // decide on stk generation based on 815 // - pairing request 816 // - io capabilities 817 // - OOB data availability 818 static void sm_setup_tk(void){ 819 820 // horizontal: initiator capabilities 821 // vertial: responder capabilities 822 static const stk_generation_method_t stk_generation_method [5] [5] = { 823 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 824 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 825 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 826 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 827 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 828 }; 829 830 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 831 #ifdef ENABLE_LE_SECURE_CONNECTIONS 832 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 833 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 834 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 835 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 836 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 837 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 838 }; 839 #endif 840 841 // default: just works 842 setup->sm_stk_generation_method = JUST_WORKS; 843 844 #ifdef ENABLE_LE_SECURE_CONNECTIONS 845 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 846 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 847 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 848 #else 849 setup->sm_use_secure_connections = 0; 850 #endif 851 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 852 853 854 // decide if OOB will be used based on SC vs. Legacy and oob flags 855 bool use_oob; 856 if (setup->sm_use_secure_connections){ 857 // In LE Secure Connections pairing, the out of band method is used if at least 858 // one device has the peer device's out of band authentication data available. 859 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; 860 } else { 861 // In LE legacy pairing, the out of band method is used if both the devices have 862 // the other device's out of band authentication data available. 863 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; 864 } 865 if (use_oob){ 866 log_info("SM: have OOB data"); 867 log_info_key("OOB", setup->sm_tk); 868 setup->sm_stk_generation_method = OOB; 869 return; 870 } 871 872 // If both devices have not set the MITM option in the Authentication Requirements 873 // Flags, then the IO capabilities shall be ignored and the Just Works association 874 // model shall be used. 875 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 876 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 877 log_info("SM: MITM not required by both -> JUST WORKS"); 878 return; 879 } 880 881 // Reset TK as it has been setup in sm_init_setup 882 sm_reset_tk(); 883 884 // Also use just works if unknown io capabilites 885 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)){ 886 return; 887 } 888 889 // Otherwise the IO capabilities of the devices shall be used to determine the 890 // pairing method as defined in Table 2.4. 891 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 892 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 893 894 #ifdef ENABLE_LE_SECURE_CONNECTIONS 895 // table not define by default 896 if (setup->sm_use_secure_connections){ 897 generation_method = stk_generation_method_with_secure_connection; 898 } 899 #endif 900 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)]; 901 902 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 903 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); 904 } 905 906 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 907 int flags = 0; 908 if (key_set & SM_KEYDIST_ENC_KEY){ 909 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 910 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 911 } 912 if (key_set & SM_KEYDIST_ID_KEY){ 913 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 914 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 915 } 916 if (key_set & SM_KEYDIST_SIGN){ 917 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 918 } 919 return flags; 920 } 921 922 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 923 setup->sm_key_distribution_received_set = 0; 924 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 925 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 926 setup->sm_key_distribution_sent_set = 0; 927 #ifdef ENABLE_LE_SIGNED_WRITE 928 setup->sm_le_device_index = -1; 929 #endif 930 } 931 932 // CSRK Key Lookup 933 934 935 static int sm_address_resolution_idle(void){ 936 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 937 } 938 939 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){ 940 (void)memcpy(sm_address_resolution_address, addr, 6); 941 sm_address_resolution_addr_type = addr_type; 942 sm_address_resolution_test = 0; 943 sm_address_resolution_mode = mode; 944 sm_address_resolution_context = context; 945 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 946 } 947 948 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 949 // check if already in list 950 btstack_linked_list_iterator_t it; 951 sm_lookup_entry_t * entry; 952 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 953 while(btstack_linked_list_iterator_has_next(&it)){ 954 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 955 if (entry->address_type != address_type) continue; 956 if (memcmp(entry->address, address, 6)) continue; 957 // already in list 958 return BTSTACK_BUSY; 959 } 960 entry = btstack_memory_sm_lookup_entry_get(); 961 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 962 entry->address_type = (bd_addr_type_t) address_type; 963 (void)memcpy(entry->address, address, 6); 964 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 965 sm_trigger_run(); 966 return 0; 967 } 968 969 // CMAC calculation using AES Engineq 970 #ifdef USE_CMAC_ENGINE 971 972 static void sm_cmac_done_trampoline(void * arg){ 973 UNUSED(arg); 974 sm_cmac_active = 0; 975 (*sm_cmac_done_callback)(sm_cmac_hash); 976 sm_trigger_run(); 977 } 978 979 int sm_cmac_ready(void){ 980 return sm_cmac_active == 0u; 981 } 982 #endif 983 984 #ifdef ENABLE_LE_SECURE_CONNECTIONS 985 // generic cmac calculation 986 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)){ 987 sm_cmac_active = 1; 988 sm_cmac_done_callback = done_callback; 989 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 990 } 991 #endif 992 993 // cmac for ATT Message signing 994 #ifdef ENABLE_LE_SIGNED_WRITE 995 996 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)){ 997 sm_cmac_active = 1; 998 sm_cmac_done_callback = done_callback; 999 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 1000 } 1001 1002 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1003 if (offset >= sm_cmac_signed_write_message_len) { 1004 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 1005 return 0; 1006 } 1007 1008 offset = sm_cmac_signed_write_message_len - 1 - offset; 1009 1010 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1011 if (offset < 3){ 1012 return sm_cmac_signed_write_header[offset]; 1013 } 1014 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1015 if (offset < actual_message_len_incl_header){ 1016 return sm_cmac_signed_write_message[offset - 3]; 1017 } 1018 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1019 } 1020 1021 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)){ 1022 // ATT Message Signing 1023 sm_cmac_signed_write_header[0] = opcode; 1024 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1025 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1026 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1027 sm_cmac_signed_write_message = message; 1028 sm_cmac_signed_write_message_len = total_message_len; 1029 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1030 } 1031 #endif 1032 1033 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1034 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1035 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1036 sm_conn->sm_pairing_active = true; 1037 switch (setup->sm_stk_generation_method){ 1038 case PK_RESP_INPUT: 1039 if (IS_RESPONDER(sm_conn->sm_role)){ 1040 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1041 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1042 } else { 1043 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1044 } 1045 break; 1046 case PK_INIT_INPUT: 1047 if (IS_RESPONDER(sm_conn->sm_role)){ 1048 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1049 } else { 1050 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1051 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1052 } 1053 break; 1054 case PK_BOTH_INPUT: 1055 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1056 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1057 break; 1058 case NUMERIC_COMPARISON: 1059 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1060 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1061 break; 1062 case JUST_WORKS: 1063 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1064 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1065 break; 1066 case OOB: 1067 // client already provided OOB data, let's skip notification. 1068 break; 1069 default: 1070 btstack_assert(false); 1071 break; 1072 } 1073 } 1074 1075 static bool sm_key_distribution_all_received(void) { 1076 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, bution_expected_set); 1077 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1078 } 1079 1080 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1081 if (sm_active_connection_handle == con_handle){ 1082 sm_timeout_stop(); 1083 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1084 log_info("sm: connection 0x%x released setup context", con_handle); 1085 1086 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1087 // generate new ec key after each pairing (that used it) 1088 if (setup->sm_use_secure_connections){ 1089 sm_ec_generate_new_key(); 1090 } 1091 #endif 1092 } 1093 } 1094 1095 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1096 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1097 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1098 sm_done_for_handle(connection->sm_handle); 1099 } 1100 1101 static int sm_key_distribution_flags_for_auth_req(void){ 1102 1103 int flags = SM_KEYDIST_ID_KEY; 1104 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1105 // encryption and signing information only if bonding requested 1106 flags |= SM_KEYDIST_ENC_KEY; 1107 #ifdef ENABLE_LE_SIGNED_WRITE 1108 flags |= SM_KEYDIST_SIGN; 1109 #endif 1110 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1111 // LinkKey for CTKD requires SC 1112 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1113 flags |= SM_KEYDIST_LINK_KEY; 1114 } 1115 #endif 1116 } 1117 return flags; 1118 } 1119 1120 static void sm_reset_setup(void){ 1121 // fill in sm setup 1122 setup->sm_state_vars = 0; 1123 setup->sm_keypress_notification = 0; 1124 setup->sm_have_oob_data = 0; 1125 sm_reset_tk(); 1126 } 1127 1128 static void sm_init_setup(sm_connection_t * sm_conn){ 1129 // fill in sm setup 1130 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1131 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1132 1133 // query client for Legacy Pairing OOB data 1134 if (sm_get_oob_data != NULL) { 1135 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1136 } 1137 1138 // if available and SC supported, also ask for SC OOB Data 1139 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1140 memset(setup->sm_ra, 0, 16); 1141 memset(setup->sm_rb, 0, 16); 1142 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1143 if (sm_get_sc_oob_data != NULL){ 1144 if (IS_RESPONDER(sm_conn->sm_role)){ 1145 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1146 sm_conn->sm_peer_addr_type, 1147 sm_conn->sm_peer_address, 1148 setup->sm_peer_confirm, 1149 setup->sm_ra); 1150 } else { 1151 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1152 sm_conn->sm_peer_addr_type, 1153 sm_conn->sm_peer_address, 1154 setup->sm_peer_confirm, 1155 setup->sm_rb); 1156 } 1157 } else { 1158 setup->sm_have_oob_data = 0; 1159 } 1160 } 1161 #endif 1162 1163 sm_pairing_packet_t * local_packet; 1164 if (IS_RESPONDER(sm_conn->sm_role)){ 1165 // slave 1166 local_packet = &setup->sm_s_pres; 1167 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1168 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1169 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1170 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1171 } else { 1172 // master 1173 local_packet = &setup->sm_m_preq; 1174 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1175 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1176 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1177 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1178 1179 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1180 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1181 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1182 } 1183 1184 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1185 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1186 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1187 // enable SC for SC only mode 1188 if (sm_sc_only_mode){ 1189 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1190 max_encryption_key_size = 16; 1191 } 1192 #endif 1193 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1194 // set CT2 if SC + Bonding + CTKD 1195 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1196 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1197 auth_req |= SM_AUTHREQ_CT2; 1198 } 1199 #endif 1200 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1201 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1202 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1203 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1204 } 1205 1206 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1207 1208 sm_pairing_packet_t * remote_packet; 1209 uint8_t keys_to_send; 1210 uint8_t keys_to_receive; 1211 if (IS_RESPONDER(sm_conn->sm_role)){ 1212 // slave / responder 1213 remote_packet = &setup->sm_m_preq; 1214 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1215 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1216 } else { 1217 // master / initiator 1218 remote_packet = &setup->sm_s_pres; 1219 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1220 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1221 } 1222 1223 // check key size 1224 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1225 // SC Only mandates 128 bit key size 1226 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1227 return SM_REASON_ENCRYPTION_KEY_SIZE; 1228 } 1229 #endif 1230 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1231 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1232 1233 // decide on STK generation method / SC 1234 sm_setup_tk(); 1235 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1236 1237 // check if STK generation method is acceptable by client 1238 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1239 1240 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1241 // Check LE SC Only mode 1242 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1243 log_info("SC Only mode active but SC not possible"); 1244 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1245 } 1246 1247 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1248 if (setup->sm_use_secure_connections){ 1249 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1250 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1251 } 1252 #endif 1253 1254 // identical to responder 1255 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1256 1257 // JUST WORKS doens't provide authentication 1258 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1259 1260 return 0; 1261 } 1262 1263 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1264 1265 // cache and reset context 1266 int matched_device_id = sm_address_resolution_test; 1267 address_resolution_mode_t mode = sm_address_resolution_mode; 1268 void * context = sm_address_resolution_context; 1269 1270 // reset context 1271 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1272 sm_address_resolution_context = NULL; 1273 sm_address_resolution_test = -1; 1274 hci_con_handle_t con_handle = 0; 1275 1276 sm_connection_t * sm_connection; 1277 sm_key_t ltk; 1278 bool have_ltk; 1279 #ifdef ENABLE_LE_CENTRAL 1280 bool trigger_pairing; 1281 #endif 1282 switch (mode){ 1283 case ADDRESS_RESOLUTION_GENERAL: 1284 break; 1285 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1286 sm_connection = (sm_connection_t *) context; 1287 con_handle = sm_connection->sm_handle; 1288 1289 // have ltk -> start encryption / send security request 1290 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1291 // "When a bond has been created between two devices, any reconnection should result in the local device 1292 // enabling or requesting encryption with the remote device before initiating any service request." 1293 1294 switch (event){ 1295 case ADDRESS_RESOLUTION_SUCCEEDED: 1296 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1297 sm_connection->sm_le_db_index = matched_device_id; 1298 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1299 1300 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1301 have_ltk = !sm_is_null_key(ltk); 1302 1303 if (sm_connection->sm_role) { 1304 #ifdef ENABLE_LE_PERIPHERAL 1305 // IRK required before, continue 1306 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1307 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1308 break; 1309 } 1310 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1311 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1312 break; 1313 } 1314 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1315 sm_connection->sm_pairing_requested = 0; 1316 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1317 // trigger security request for Proactive Authentication if LTK available 1318 trigger_security_request = trigger_security_request || have_ltk; 1319 #endif 1320 1321 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1322 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1323 1324 if (trigger_security_request){ 1325 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1326 if (have_ltk){ 1327 sm_reencryption_started(sm_connection); 1328 } else { 1329 sm_pairing_started(sm_connection); 1330 } 1331 sm_trigger_run(); 1332 } 1333 #endif 1334 } else { 1335 1336 #ifdef ENABLE_LE_CENTRAL 1337 // check if pairing already requested and reset requests 1338 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1339 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1340 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1341 sm_connection->sm_security_request_received = 0; 1342 sm_connection->sm_pairing_requested = 0; 1343 bool trigger_reencryption = false; 1344 1345 if (have_ltk){ 1346 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1347 trigger_reencryption = true; 1348 #else 1349 if (trigger_pairing){ 1350 trigger_reencryption = true; 1351 } else { 1352 log_info("central: defer enabling encryption for bonded device"); 1353 } 1354 #endif 1355 } 1356 1357 if (trigger_reencryption){ 1358 log_info("central: enable encryption for bonded device"); 1359 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1360 break; 1361 } 1362 1363 // pairing_request -> send pairing request 1364 if (trigger_pairing){ 1365 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1366 break; 1367 } 1368 #endif 1369 } 1370 break; 1371 case ADDRESS_RESOLUTION_FAILED: 1372 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1373 if (sm_connection->sm_role) { 1374 #ifdef ENABLE_LE_PERIPHERAL 1375 // LTK request received before, IRK required -> negative LTK reply 1376 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1377 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1378 } 1379 // send security request if requested 1380 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1381 sm_connection->sm_pairing_requested = 0; 1382 if (trigger_security_request){ 1383 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1384 sm_pairing_started(sm_connection); 1385 } 1386 break; 1387 #endif 1388 } 1389 #ifdef ENABLE_LE_CENTRAL 1390 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1391 sm_connection->sm_security_request_received = 0; 1392 sm_connection->sm_pairing_requested = 0; 1393 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1394 #endif 1395 break; 1396 1397 default: 1398 btstack_assert(false); 1399 break; 1400 } 1401 break; 1402 default: 1403 break; 1404 } 1405 1406 switch (event){ 1407 case ADDRESS_RESOLUTION_SUCCEEDED: 1408 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1409 break; 1410 case ADDRESS_RESOLUTION_FAILED: 1411 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1412 break; 1413 default: 1414 btstack_assert(false); 1415 break; 1416 } 1417 } 1418 1419 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1420 int le_db_index = -1; 1421 1422 // lookup device based on IRK 1423 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1424 int i; 1425 for (i=0; i < le_device_db_max_count(); i++){ 1426 sm_key_t irk; 1427 bd_addr_t address; 1428 int address_type = BD_ADDR_TYPE_UNKNOWN; 1429 le_device_db_info(i, &address_type, address, irk); 1430 // skip unused entries 1431 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1432 // compare Identity Address 1433 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1434 // compare Identity Resolving Key 1435 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1436 1437 log_info("sm: device found for IRK, updating"); 1438 le_db_index = i; 1439 break; 1440 } 1441 } else { 1442 // assert IRK is set to zero 1443 memset(setup->sm_peer_irk, 0, 16); 1444 } 1445 1446 // if not found, lookup via public address if possible 1447 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1448 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1449 int i; 1450 for (i=0; i < le_device_db_max_count(); i++){ 1451 bd_addr_t address; 1452 int address_type = BD_ADDR_TYPE_UNKNOWN; 1453 le_device_db_info(i, &address_type, address, NULL); 1454 // skip unused entries 1455 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1456 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1457 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1458 log_info("sm: device found for public address, updating"); 1459 le_db_index = i; 1460 break; 1461 } 1462 } 1463 } 1464 1465 // if not found, add to db 1466 bool new_to_le_device_db = false; 1467 if (le_db_index < 0) { 1468 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1469 new_to_le_device_db = true; 1470 } 1471 1472 if (le_db_index >= 0){ 1473 1474 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1475 if (!new_to_le_device_db){ 1476 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1477 } 1478 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1479 #else 1480 UNUSED(new_to_le_device_db); 1481 #endif 1482 1483 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1484 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1485 sm_conn->sm_le_db_index = le_db_index; 1486 1487 #ifdef ENABLE_LE_SIGNED_WRITE 1488 // store local CSRK 1489 setup->sm_le_device_index = le_db_index; 1490 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1491 log_info("sm: store local CSRK"); 1492 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1493 le_device_db_local_counter_set(le_db_index, 0); 1494 } 1495 1496 // store remote CSRK 1497 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1498 log_info("sm: store remote CSRK"); 1499 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1500 le_device_db_remote_counter_set(le_db_index, 0); 1501 } 1502 #endif 1503 // store encryption information for secure connections: LTK generated by ECDH 1504 if (setup->sm_use_secure_connections){ 1505 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1506 uint8_t zero_rand[8]; 1507 memset(zero_rand, 0, 8); 1508 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1509 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1510 } 1511 1512 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1513 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1514 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1515 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1516 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1517 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1518 1519 } 1520 } 1521 } 1522 1523 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1524 1525 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1526 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1527 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1528 & SM_AUTHREQ_BONDING ) != 0u; 1529 1530 if (bonding_enabled){ 1531 sm_store_bonding_information(sm_conn); 1532 } else { 1533 log_info("Ignoring received keys, bonding not enabled"); 1534 } 1535 } 1536 1537 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1538 sm_conn->sm_pairing_failed_reason = reason; 1539 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1540 } 1541 1542 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1543 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1544 } 1545 1546 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1547 1548 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1549 static int sm_passkey_used(stk_generation_method_t method); 1550 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1551 1552 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1553 if (setup->sm_stk_generation_method == OOB){ 1554 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1555 } else { 1556 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); 1557 } 1558 } 1559 1560 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1561 if (IS_RESPONDER(sm_conn->sm_role)){ 1562 // Responder 1563 if (setup->sm_stk_generation_method == OOB){ 1564 // generate Nb 1565 log_info("Generate Nb"); 1566 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); 1567 } else { 1568 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1569 } 1570 } else { 1571 // Initiator role 1572 switch (setup->sm_stk_generation_method){ 1573 case JUST_WORKS: 1574 sm_sc_prepare_dhkey_check(sm_conn); 1575 break; 1576 1577 case NUMERIC_COMPARISON: 1578 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1579 break; 1580 case PK_INIT_INPUT: 1581 case PK_RESP_INPUT: 1582 case PK_BOTH_INPUT: 1583 if (setup->sm_passkey_bit < 20u) { 1584 sm_sc_start_calculating_local_confirm(sm_conn); 1585 } else { 1586 sm_sc_prepare_dhkey_check(sm_conn); 1587 } 1588 break; 1589 case OOB: 1590 sm_sc_prepare_dhkey_check(sm_conn); 1591 break; 1592 default: 1593 btstack_assert(false); 1594 break; 1595 } 1596 } 1597 } 1598 1599 static void sm_sc_cmac_done(uint8_t * hash){ 1600 log_info("sm_sc_cmac_done: "); 1601 log_info_hexdump(hash, 16); 1602 1603 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1604 sm_sc_oob_state = SM_SC_OOB_IDLE; 1605 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1606 return; 1607 } 1608 1609 sm_connection_t * sm_conn = sm_cmac_connection; 1610 sm_cmac_connection = NULL; 1611 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1612 link_key_type_t link_key_type; 1613 #endif 1614 1615 switch (sm_conn->sm_engine_state){ 1616 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1617 (void)memcpy(setup->sm_local_confirm, hash, 16); 1618 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1619 break; 1620 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1621 // check 1622 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1623 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1624 break; 1625 } 1626 sm_sc_state_after_receiving_random(sm_conn); 1627 break; 1628 case SM_SC_W4_CALCULATE_G2: { 1629 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1630 big_endian_store_32(setup->sm_tk, 12, vab); 1631 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1632 sm_trigger_user_response(sm_conn); 1633 break; 1634 } 1635 case SM_SC_W4_CALCULATE_F5_SALT: 1636 (void)memcpy(setup->sm_t, hash, 16); 1637 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1638 break; 1639 case SM_SC_W4_CALCULATE_F5_MACKEY: 1640 (void)memcpy(setup->sm_mackey, hash, 16); 1641 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1642 break; 1643 case SM_SC_W4_CALCULATE_F5_LTK: 1644 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1645 // Errata Service Release to the Bluetooth Specification: ESR09 1646 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1647 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1648 (void)memcpy(setup->sm_ltk, hash, 16); 1649 (void)memcpy(setup->sm_local_ltk, hash, 16); 1650 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1651 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1652 break; 1653 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1654 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1655 if (IS_RESPONDER(sm_conn->sm_role)){ 1656 // responder 1657 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1658 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1659 } else { 1660 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1661 } 1662 } else { 1663 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1664 } 1665 break; 1666 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1667 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1668 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1669 break; 1670 } 1671 if (IS_RESPONDER(sm_conn->sm_role)){ 1672 // responder 1673 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1674 } else { 1675 // initiator 1676 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1677 } 1678 break; 1679 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1680 case SM_SC_W4_CALCULATE_ILK: 1681 (void)memcpy(setup->sm_t, hash, 16); 1682 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1683 break; 1684 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1685 reverse_128(hash, setup->sm_t); 1686 link_key_type = sm_conn->sm_connection_authenticated ? 1687 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1688 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1689 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1690 if (IS_RESPONDER(sm_conn->sm_role)){ 1691 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1692 } else { 1693 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1694 } 1695 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1696 sm_done_for_handle(sm_conn->sm_handle); 1697 break; 1698 case SM_BR_EDR_W4_CALCULATE_ILK: 1699 (void)memcpy(setup->sm_t, hash, 16); 1700 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1701 break; 1702 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1703 log_info("Derived LE LTK from BR/EDR Link Key"); 1704 log_info_key("Link Key", hash); 1705 (void)memcpy(setup->sm_ltk, hash, 16); 1706 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1707 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1708 sm_store_bonding_information(sm_conn); 1709 sm_done_for_handle(sm_conn->sm_handle); 1710 break; 1711 #endif 1712 default: 1713 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1714 break; 1715 } 1716 sm_trigger_run(); 1717 } 1718 1719 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){ 1720 const uint16_t message_len = 65; 1721 sm_cmac_connection = sm_conn; 1722 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1723 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1724 sm_cmac_sc_buffer[64] = z; 1725 log_info("f4 key"); 1726 log_info_hexdump(x, 16); 1727 log_info("f4 message"); 1728 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1729 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1730 } 1731 1732 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1733 static const uint8_t f5_length[] = { 0x01, 0x00}; 1734 1735 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1736 1737 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1738 1739 log_info("f5_calculate_salt"); 1740 // calculate salt for f5 1741 const uint16_t message_len = 32; 1742 sm_cmac_connection = sm_conn; 1743 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1744 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1745 } 1746 1747 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){ 1748 const uint16_t message_len = 53; 1749 sm_cmac_connection = sm_conn; 1750 1751 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1752 sm_cmac_sc_buffer[0] = 0; 1753 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1754 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1755 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1756 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1757 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1758 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1759 log_info("f5 key"); 1760 log_info_hexdump(t, 16); 1761 log_info("f5 message for MacKey"); 1762 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1763 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1764 } 1765 1766 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1767 sm_key56_t bd_addr_master, bd_addr_slave; 1768 bd_addr_master[0] = setup->sm_m_addr_type; 1769 bd_addr_slave[0] = setup->sm_s_addr_type; 1770 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1771 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1772 if (IS_RESPONDER(sm_conn->sm_role)){ 1773 // responder 1774 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1775 } else { 1776 // initiator 1777 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1778 } 1779 } 1780 1781 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1782 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1783 const uint16_t message_len = 53; 1784 sm_cmac_connection = sm_conn; 1785 sm_cmac_sc_buffer[0] = 1; 1786 // 1..52 setup before 1787 log_info("f5 key"); 1788 log_info_hexdump(t, 16); 1789 log_info("f5 message for LTK"); 1790 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1791 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1792 } 1793 1794 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1795 f5_ltk(sm_conn, setup->sm_t); 1796 } 1797 1798 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){ 1799 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1800 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1801 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1802 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1803 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1804 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1805 } 1806 1807 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1808 const uint16_t message_len = 65; 1809 sm_cmac_connection = sm_conn; 1810 log_info("f6 key"); 1811 log_info_hexdump(w, 16); 1812 log_info("f6 message"); 1813 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1814 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1815 } 1816 1817 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1818 // - U is 256 bits 1819 // - V is 256 bits 1820 // - X is 128 bits 1821 // - Y is 128 bits 1822 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){ 1823 const uint16_t message_len = 80; 1824 sm_cmac_connection = sm_conn; 1825 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1826 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1827 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1828 log_info("g2 key"); 1829 log_info_hexdump(x, 16); 1830 log_info("g2 message"); 1831 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1832 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1833 } 1834 1835 static void g2_calculate(sm_connection_t * sm_conn) { 1836 // calc Va if numeric comparison 1837 if (IS_RESPONDER(sm_conn->sm_role)){ 1838 // responder 1839 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1840 } else { 1841 // initiator 1842 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1843 } 1844 } 1845 1846 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1847 uint8_t z = 0; 1848 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1849 // some form of passkey 1850 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1851 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1852 setup->sm_passkey_bit++; 1853 } 1854 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1855 } 1856 1857 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1858 // OOB 1859 if (setup->sm_stk_generation_method == OOB){ 1860 if (IS_RESPONDER(sm_conn->sm_role)){ 1861 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1862 } else { 1863 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1864 } 1865 return; 1866 } 1867 1868 uint8_t z = 0; 1869 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1870 // some form of passkey 1871 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1872 // sm_passkey_bit was increased before sending confirm value 1873 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1874 } 1875 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1876 } 1877 1878 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1879 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1880 1881 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1882 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1883 return; 1884 } else { 1885 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1886 } 1887 } 1888 1889 static void sm_sc_dhkey_calculated(void * arg){ 1890 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1891 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1892 if (sm_conn == NULL) return; 1893 1894 log_info("dhkey"); 1895 log_info_hexdump(&setup->sm_dhkey[0], 32); 1896 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1897 // trigger next step 1898 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1899 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1900 } 1901 sm_trigger_run(); 1902 } 1903 1904 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1905 // calculate DHKCheck 1906 sm_key56_t bd_addr_master, bd_addr_slave; 1907 bd_addr_master[0] = setup->sm_m_addr_type; 1908 bd_addr_slave[0] = setup->sm_s_addr_type; 1909 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1910 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1911 uint8_t iocap_a[3]; 1912 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1913 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1914 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1915 uint8_t iocap_b[3]; 1916 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1917 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1918 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1919 if (IS_RESPONDER(sm_conn->sm_role)){ 1920 // responder 1921 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1922 f6_engine(sm_conn, setup->sm_mackey); 1923 } else { 1924 // initiator 1925 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1926 f6_engine(sm_conn, setup->sm_mackey); 1927 } 1928 } 1929 1930 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1931 // validate E = f6() 1932 sm_key56_t bd_addr_master, bd_addr_slave; 1933 bd_addr_master[0] = setup->sm_m_addr_type; 1934 bd_addr_slave[0] = setup->sm_s_addr_type; 1935 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1936 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1937 1938 uint8_t iocap_a[3]; 1939 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1940 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1941 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1942 uint8_t iocap_b[3]; 1943 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1944 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1945 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1946 if (IS_RESPONDER(sm_conn->sm_role)){ 1947 // responder 1948 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1949 f6_engine(sm_conn, setup->sm_mackey); 1950 } else { 1951 // initiator 1952 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1953 f6_engine(sm_conn, setup->sm_mackey); 1954 } 1955 } 1956 1957 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1958 1959 // 1960 // Link Key Conversion Function h6 1961 // 1962 // h6(W, keyID) = AES-CMAC_W(keyID) 1963 // - W is 128 bits 1964 // - keyID is 32 bits 1965 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1966 const uint16_t message_len = 4; 1967 sm_cmac_connection = sm_conn; 1968 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1969 log_info("h6 key"); 1970 log_info_hexdump(w, 16); 1971 log_info("h6 message"); 1972 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1973 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1974 } 1975 // 1976 // Link Key Conversion Function h7 1977 // 1978 // h7(SALT, W) = AES-CMAC_SALT(W) 1979 // - SALT is 128 bits 1980 // - W is 128 bits 1981 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1982 const uint16_t message_len = 16; 1983 sm_cmac_connection = sm_conn; 1984 log_info("h7 key"); 1985 log_info_hexdump(salt, 16); 1986 log_info("h7 message"); 1987 log_info_hexdump(w, 16); 1988 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1989 } 1990 1991 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1992 // Errata Service Release to the Bluetooth Specification: ESR09 1993 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1994 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1995 1996 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 1997 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1998 } 1999 2000 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2001 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2002 } 2003 2004 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2005 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2006 } 2007 2008 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2009 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2010 } 2011 2012 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2013 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2014 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2015 } 2016 2017 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2018 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2019 h7_engine(sm_conn, salt, setup->sm_link_key); 2020 } 2021 2022 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2023 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2024 btstack_assert(hci_connection != NULL); 2025 reverse_128(hci_connection->link_key, setup->sm_link_key); 2026 setup->sm_link_key_type = hci_connection->link_key_type; 2027 } 2028 2029 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2030 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; 2031 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2032 } 2033 2034 #endif 2035 2036 #endif 2037 2038 // key management legacy connections: 2039 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2040 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2041 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2042 // - responder reconnects: responder uses LTK receveived from master 2043 2044 // key management secure connections: 2045 // - both devices store same LTK from ECDH key exchange. 2046 2047 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2048 static void sm_load_security_info(sm_connection_t * sm_connection){ 2049 int encryption_key_size; 2050 int authenticated; 2051 int authorized; 2052 int secure_connection; 2053 2054 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2055 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2056 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2057 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); 2058 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2059 sm_connection->sm_connection_authenticated = authenticated; 2060 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2061 sm_connection->sm_connection_sc = secure_connection; 2062 } 2063 #endif 2064 2065 #ifdef ENABLE_LE_PERIPHERAL 2066 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2067 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2068 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2069 // re-establish used key encryption size 2070 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2071 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2072 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2073 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2074 // Legacy paring -> not SC 2075 sm_connection->sm_connection_sc = 0; 2076 log_info("sm: received ltk request with key size %u, authenticated %u", 2077 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2078 } 2079 #endif 2080 2081 // distributed key generation 2082 static bool sm_run_dpkg(void){ 2083 switch (dkg_state){ 2084 case DKG_CALC_IRK: 2085 // already busy? 2086 if (sm_aes128_state == SM_AES128_IDLE) { 2087 log_info("DKG_CALC_IRK started"); 2088 // IRK = d1(IR, 1, 0) 2089 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2090 sm_aes128_state = SM_AES128_ACTIVE; 2091 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2092 return true; 2093 } 2094 break; 2095 case DKG_CALC_DHK: 2096 // already busy? 2097 if (sm_aes128_state == SM_AES128_IDLE) { 2098 log_info("DKG_CALC_DHK started"); 2099 // DHK = d1(IR, 3, 0) 2100 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2101 sm_aes128_state = SM_AES128_ACTIVE; 2102 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2103 return true; 2104 } 2105 break; 2106 default: 2107 break; 2108 } 2109 return false; 2110 } 2111 2112 // random address updates 2113 static bool sm_run_rau(void){ 2114 switch (rau_state){ 2115 case RAU_GET_RANDOM: 2116 rau_state = RAU_W4_RANDOM; 2117 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2118 return true; 2119 case RAU_GET_ENC: 2120 // already busy? 2121 if (sm_aes128_state == SM_AES128_IDLE) { 2122 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2123 sm_aes128_state = SM_AES128_ACTIVE; 2124 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2125 return true; 2126 } 2127 break; 2128 default: 2129 break; 2130 } 2131 return false; 2132 } 2133 2134 // CSRK Lookup 2135 static bool sm_run_csrk(void){ 2136 btstack_linked_list_iterator_t it; 2137 2138 // -- if csrk lookup ready, find connection that require csrk lookup 2139 if (sm_address_resolution_idle()){ 2140 hci_connections_get_iterator(&it); 2141 while(btstack_linked_list_iterator_has_next(&it)){ 2142 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2143 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2144 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2145 // and start lookup 2146 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); 2147 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2148 break; 2149 } 2150 } 2151 } 2152 2153 // -- if csrk lookup ready, resolved addresses for received addresses 2154 if (sm_address_resolution_idle()) { 2155 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2156 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2157 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2158 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2159 btstack_memory_sm_lookup_entry_free(entry); 2160 } 2161 } 2162 2163 // -- Continue with CSRK device lookup by public or resolvable private address 2164 if (!sm_address_resolution_idle()){ 2165 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2166 while (sm_address_resolution_test < le_device_db_max_count()){ 2167 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2168 bd_addr_t addr; 2169 sm_key_t irk; 2170 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2171 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2172 2173 // skip unused entries 2174 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2175 sm_address_resolution_test++; 2176 continue; 2177 } 2178 2179 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2180 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2181 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2182 break; 2183 } 2184 2185 // if connection type is public, it must be a different one 2186 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2187 sm_address_resolution_test++; 2188 continue; 2189 } 2190 2191 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2192 2193 log_info("LE Device Lookup: calculate AH"); 2194 log_info_key("IRK", irk); 2195 2196 (void)memcpy(sm_aes128_key, irk, 16); 2197 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2198 sm_address_resolution_ah_calculation_active = 1; 2199 sm_aes128_state = SM_AES128_ACTIVE; 2200 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2201 return true; 2202 } 2203 2204 if (sm_address_resolution_test >= le_device_db_max_count()){ 2205 log_info("LE Device Lookup: not found"); 2206 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2207 } 2208 } 2209 return false; 2210 } 2211 2212 // SC OOB 2213 static bool sm_run_oob(void){ 2214 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2215 switch (sm_sc_oob_state){ 2216 case SM_SC_OOB_W2_CALC_CONFIRM: 2217 if (!sm_cmac_ready()) break; 2218 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2219 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2220 return true; 2221 default: 2222 break; 2223 } 2224 #endif 2225 return false; 2226 } 2227 2228 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2229 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2230 } 2231 2232 // handle basic actions that don't requires the full context 2233 static bool sm_run_basic(void){ 2234 btstack_linked_list_iterator_t it; 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 switch(sm_connection->sm_engine_state){ 2240 2241 // general 2242 case SM_GENERAL_SEND_PAIRING_FAILED: { 2243 uint8_t buffer[2]; 2244 buffer[0] = SM_CODE_PAIRING_FAILED; 2245 buffer[1] = sm_connection->sm_pairing_failed_reason; 2246 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2247 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2248 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2249 sm_done_for_handle(sm_connection->sm_handle); 2250 break; 2251 } 2252 2253 // responder side 2254 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2255 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2256 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2257 return true; 2258 2259 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2260 case SM_SC_RECEIVED_LTK_REQUEST: 2261 switch (sm_connection->sm_irk_lookup_state){ 2262 case IRK_LOOKUP_FAILED: 2263 log_info("LTK Request: IRK Lookup Failed)"); 2264 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2265 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2266 return true; 2267 default: 2268 break; 2269 } 2270 break; 2271 #endif 2272 default: 2273 break; 2274 } 2275 } 2276 return false; 2277 } 2278 2279 static void sm_run_activate_connection(void){ 2280 // Find connections that requires setup context and make active if no other is locked 2281 btstack_linked_list_iterator_t it; 2282 hci_connections_get_iterator(&it); 2283 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2284 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2285 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2286 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2287 bool done = true; 2288 int err; 2289 UNUSED(err); 2290 2291 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2292 // assert ec key is ready 2293 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2294 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2295 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2296 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2297 sm_ec_generate_new_key(); 2298 } 2299 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2300 continue; 2301 } 2302 } 2303 #endif 2304 2305 switch (sm_connection->sm_engine_state) { 2306 #ifdef ENABLE_LE_PERIPHERAL 2307 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2308 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2309 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2310 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2311 case SM_SC_RECEIVED_LTK_REQUEST: 2312 #endif 2313 #endif 2314 #ifdef ENABLE_LE_CENTRAL 2315 case SM_INITIATOR_PH4_HAS_LTK: 2316 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2317 #endif 2318 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2319 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2320 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2321 #endif 2322 // just lock context 2323 break; 2324 default: 2325 done = false; 2326 break; 2327 } 2328 if (done){ 2329 sm_active_connection_handle = sm_connection->sm_handle; 2330 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); 2331 } 2332 } 2333 } 2334 2335 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2336 int i; 2337 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2338 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2339 uint8_t action = 0; 2340 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2341 if (flags & (1u<<i)){ 2342 bool clear_flag = true; 2343 switch (i){ 2344 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2345 case SM_KEYPRESS_PASSKEY_CLEARED: 2346 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2347 default: 2348 break; 2349 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2350 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2351 num_actions--; 2352 clear_flag = num_actions == 0u; 2353 break; 2354 } 2355 if (clear_flag){ 2356 flags &= ~(1<<i); 2357 } 2358 action = i; 2359 break; 2360 } 2361 } 2362 setup->sm_keypress_notification = (num_actions << 5) | flags; 2363 2364 // send keypress notification 2365 uint8_t buffer[2]; 2366 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2367 buffer[1] = action; 2368 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2369 2370 // try 2371 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2372 } 2373 2374 static void sm_run_distribute_keys(sm_connection_t * connection){ 2375 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2376 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2377 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2378 uint8_t buffer[17]; 2379 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2380 reverse_128(setup->sm_ltk, &buffer[1]); 2381 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2382 sm_timeout_reset(connection); 2383 return; 2384 } 2385 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2386 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2387 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2388 uint8_t buffer[11]; 2389 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2390 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2391 reverse_64(setup->sm_local_rand, &buffer[3]); 2392 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2393 sm_timeout_reset(connection); 2394 return; 2395 } 2396 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2397 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2398 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2399 uint8_t buffer[17]; 2400 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2401 reverse_128(sm_persistent_irk, &buffer[1]); 2402 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2403 sm_timeout_reset(connection); 2404 return; 2405 } 2406 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2407 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2408 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2409 bd_addr_t local_address; 2410 uint8_t buffer[8]; 2411 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2412 switch (gap_random_address_get_mode()){ 2413 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2414 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2415 // public or static random 2416 gap_le_get_own_address(&buffer[1], local_address); 2417 break; 2418 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2419 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2420 // fallback to public 2421 gap_local_bd_addr(local_address); 2422 buffer[1] = 0; 2423 break; 2424 default: 2425 btstack_assert(false); 2426 break; 2427 } 2428 reverse_bd_addr(local_address, &buffer[2]); 2429 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2430 sm_timeout_reset(connection); 2431 return; 2432 } 2433 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2434 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2435 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2436 2437 #ifdef ENABLE_LE_SIGNED_WRITE 2438 // hack to reproduce test runs 2439 if (test_use_fixed_local_csrk){ 2440 memset(setup->sm_local_csrk, 0xcc, 16); 2441 } 2442 2443 // store local CSRK 2444 if (setup->sm_le_device_index >= 0){ 2445 log_info("sm: store local CSRK"); 2446 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2447 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2448 } 2449 #endif 2450 2451 uint8_t buffer[17]; 2452 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2453 reverse_128(setup->sm_local_csrk, &buffer[1]); 2454 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2455 sm_timeout_reset(connection); 2456 return; 2457 } 2458 btstack_assert(false); 2459 } 2460 2461 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2462 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2463 // requirements to derive link key from LE: 2464 // - use secure connections 2465 if (setup->sm_use_secure_connections == 0) return false; 2466 // - bonding needs to be enabled: 2467 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; 2468 if (!bonding_enabled) return false; 2469 // - need identity address / public addr 2470 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2471 if (!have_identity_address_info) return false; 2472 // - 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) 2473 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2474 // If SC is authenticated, we consider it safe to overwrite a stored key. 2475 // 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. 2476 uint8_t link_key[16]; 2477 link_key_type_t link_key_type; 2478 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2479 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2480 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2481 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2482 return false; 2483 } 2484 // get started (all of the above are true) 2485 return true; 2486 #else 2487 UNUSED(sm_connection); 2488 return false; 2489 #endif 2490 } 2491 2492 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2493 if (sm_ctkd_from_le(connection)){ 2494 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; 2495 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2496 } else { 2497 connection->sm_engine_state = SM_RESPONDER_IDLE; 2498 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2499 sm_done_for_handle(connection->sm_handle); 2500 } 2501 } 2502 2503 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2504 if (sm_ctkd_from_le(connection)){ 2505 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; 2506 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2507 } else { 2508 sm_master_pairing_success(connection); 2509 } 2510 } 2511 2512 static void sm_run(void){ 2513 2514 // assert that stack has already bootet 2515 if (hci_get_state() != HCI_STATE_WORKING) return; 2516 2517 // assert that we can send at least commands 2518 if (!hci_can_send_command_packet_now()) return; 2519 2520 // pause until IR/ER are ready 2521 if (sm_persistent_keys_random_active) return; 2522 2523 bool done; 2524 2525 // 2526 // non-connection related behaviour 2527 // 2528 2529 done = sm_run_dpkg(); 2530 if (done) return; 2531 2532 done = sm_run_rau(); 2533 if (done) return; 2534 2535 done = sm_run_csrk(); 2536 if (done) return; 2537 2538 done = sm_run_oob(); 2539 if (done) return; 2540 2541 // assert that we can send at least commands - cmd might have been sent by crypto engine 2542 if (!hci_can_send_command_packet_now()) return; 2543 2544 // handle basic actions that don't requires the full context 2545 done = sm_run_basic(); 2546 if (done) return; 2547 2548 // 2549 // active connection handling 2550 // -- use loop to handle next connection if lock on setup context is released 2551 2552 while (true) { 2553 2554 sm_run_activate_connection(); 2555 2556 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2557 2558 // 2559 // active connection handling 2560 // 2561 2562 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2563 if (!connection) { 2564 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2565 return; 2566 } 2567 2568 // assert that we could send a SM PDU - not needed for all of the following 2569 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2570 log_info("cannot send now, requesting can send now event"); 2571 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2572 return; 2573 } 2574 2575 // send keypress notifications 2576 if (setup->sm_keypress_notification){ 2577 sm_run_send_keypress_notification(connection); 2578 return; 2579 } 2580 2581 int key_distribution_flags; 2582 UNUSED(key_distribution_flags); 2583 int err; 2584 UNUSED(err); 2585 bool have_ltk; 2586 uint8_t ltk[16]; 2587 2588 log_info("sm_run: state %u", connection->sm_engine_state); 2589 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2590 log_info("sm_run // cannot send"); 2591 } 2592 switch (connection->sm_engine_state){ 2593 2594 // secure connections, initiator + responding states 2595 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2596 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2597 if (!sm_cmac_ready()) break; 2598 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2599 sm_sc_calculate_local_confirm(connection); 2600 break; 2601 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2602 if (!sm_cmac_ready()) break; 2603 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2604 sm_sc_calculate_remote_confirm(connection); 2605 break; 2606 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2607 if (!sm_cmac_ready()) break; 2608 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2609 sm_sc_calculate_f6_for_dhkey_check(connection); 2610 break; 2611 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2612 if (!sm_cmac_ready()) break; 2613 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2614 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2615 break; 2616 case SM_SC_W2_CALCULATE_F5_SALT: 2617 if (!sm_cmac_ready()) break; 2618 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2619 f5_calculate_salt(connection); 2620 break; 2621 case SM_SC_W2_CALCULATE_F5_MACKEY: 2622 if (!sm_cmac_ready()) break; 2623 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2624 f5_calculate_mackey(connection); 2625 break; 2626 case SM_SC_W2_CALCULATE_F5_LTK: 2627 if (!sm_cmac_ready()) break; 2628 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2629 f5_calculate_ltk(connection); 2630 break; 2631 case SM_SC_W2_CALCULATE_G2: 2632 if (!sm_cmac_ready()) break; 2633 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2634 g2_calculate(connection); 2635 break; 2636 #endif 2637 2638 #ifdef ENABLE_LE_CENTRAL 2639 // initiator side 2640 2641 case SM_INITIATOR_PH4_HAS_LTK: { 2642 sm_reset_setup(); 2643 sm_load_security_info(connection); 2644 sm_reencryption_started(connection); 2645 2646 sm_key_t peer_ltk_flipped; 2647 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2648 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2649 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2650 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2651 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2652 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2653 return; 2654 } 2655 2656 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2657 sm_reset_setup(); 2658 sm_init_setup(connection); 2659 sm_timeout_start(connection); 2660 sm_pairing_started(connection); 2661 2662 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2663 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2664 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2665 sm_timeout_reset(connection); 2666 break; 2667 #endif 2668 2669 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2670 2671 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2672 bool trigger_user_response = false; 2673 bool trigger_start_calculating_local_confirm = false; 2674 uint8_t buffer[65]; 2675 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2676 // 2677 reverse_256(&ec_q[0], &buffer[1]); 2678 reverse_256(&ec_q[32], &buffer[33]); 2679 2680 #ifdef ENABLE_TESTING_SUPPORT 2681 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2682 log_info("testing_support: invalidating public key"); 2683 // flip single bit of public key coordinate 2684 buffer[1] ^= 1; 2685 } 2686 #endif 2687 2688 // stk generation method 2689 // passkey entry: notify app to show passkey or to request passkey 2690 switch (setup->sm_stk_generation_method){ 2691 case JUST_WORKS: 2692 case NUMERIC_COMPARISON: 2693 if (IS_RESPONDER(connection->sm_role)){ 2694 // responder 2695 trigger_start_calculating_local_confirm = true; 2696 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2697 } else { 2698 // initiator 2699 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2700 } 2701 break; 2702 case PK_INIT_INPUT: 2703 case PK_RESP_INPUT: 2704 case PK_BOTH_INPUT: 2705 // use random TK for display 2706 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2707 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2708 setup->sm_passkey_bit = 0; 2709 2710 if (IS_RESPONDER(connection->sm_role)){ 2711 // responder 2712 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2713 } else { 2714 // initiator 2715 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2716 } 2717 trigger_user_response = true; 2718 break; 2719 case OOB: 2720 if (IS_RESPONDER(connection->sm_role)){ 2721 // responder 2722 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2723 } else { 2724 // initiator 2725 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2726 } 2727 break; 2728 default: 2729 btstack_assert(false); 2730 break; 2731 } 2732 2733 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2734 sm_timeout_reset(connection); 2735 2736 // trigger user response and calc confirm after sending pdu 2737 if (trigger_user_response){ 2738 sm_trigger_user_response(connection); 2739 } 2740 if (trigger_start_calculating_local_confirm){ 2741 sm_sc_start_calculating_local_confirm(connection); 2742 } 2743 break; 2744 } 2745 case SM_SC_SEND_CONFIRMATION: { 2746 uint8_t buffer[17]; 2747 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2748 reverse_128(setup->sm_local_confirm, &buffer[1]); 2749 if (IS_RESPONDER(connection->sm_role)){ 2750 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2751 } else { 2752 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2753 } 2754 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2755 sm_timeout_reset(connection); 2756 break; 2757 } 2758 case SM_SC_SEND_PAIRING_RANDOM: { 2759 uint8_t buffer[17]; 2760 buffer[0] = SM_CODE_PAIRING_RANDOM; 2761 reverse_128(setup->sm_local_nonce, &buffer[1]); 2762 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2763 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2764 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2765 if (IS_RESPONDER(connection->sm_role)){ 2766 // responder 2767 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2768 } else { 2769 // initiator 2770 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2771 } 2772 } else { 2773 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2774 if (IS_RESPONDER(connection->sm_role)){ 2775 // responder 2776 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2777 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2778 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2779 } else { 2780 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2781 sm_sc_prepare_dhkey_check(connection); 2782 } 2783 } else { 2784 // initiator 2785 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2786 } 2787 } 2788 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2789 sm_timeout_reset(connection); 2790 break; 2791 } 2792 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2793 uint8_t buffer[17]; 2794 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2795 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2796 2797 if (IS_RESPONDER(connection->sm_role)){ 2798 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2799 } else { 2800 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2801 } 2802 2803 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2804 sm_timeout_reset(connection); 2805 break; 2806 } 2807 2808 #endif 2809 2810 #ifdef ENABLE_LE_PERIPHERAL 2811 2812 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2813 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2814 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2815 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2816 sm_timeout_start(connection); 2817 break; 2818 } 2819 2820 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2821 case SM_SC_RECEIVED_LTK_REQUEST: 2822 switch (connection->sm_irk_lookup_state){ 2823 case IRK_LOOKUP_SUCCEEDED: 2824 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2825 // start using context by loading security info 2826 sm_reset_setup(); 2827 sm_load_security_info(connection); 2828 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2829 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2830 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2831 sm_reencryption_started(connection); 2832 sm_trigger_run(); 2833 break; 2834 } 2835 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2836 connection->sm_engine_state = SM_RESPONDER_IDLE; 2837 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2838 return; 2839 default: 2840 // just wait until IRK lookup is completed 2841 break; 2842 } 2843 break; 2844 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2845 2846 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2847 sm_reset_setup(); 2848 2849 // handle Pairing Request with LTK available 2850 switch (connection->sm_irk_lookup_state) { 2851 case IRK_LOOKUP_SUCCEEDED: 2852 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2853 have_ltk = !sm_is_null_key(ltk); 2854 if (have_ltk){ 2855 log_info("pairing request but LTK available"); 2856 // emit re-encryption start/fail sequence 2857 sm_reencryption_started(connection); 2858 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2859 } 2860 break; 2861 default: 2862 break; 2863 } 2864 2865 sm_init_setup(connection); 2866 sm_pairing_started(connection); 2867 2868 // recover pairing request 2869 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2870 err = sm_stk_generation_init(connection); 2871 2872 #ifdef ENABLE_TESTING_SUPPORT 2873 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2874 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2875 err = test_pairing_failure; 2876 } 2877 #endif 2878 if (err != 0){ 2879 sm_pairing_error(connection, err); 2880 sm_trigger_run(); 2881 break; 2882 } 2883 2884 sm_timeout_start(connection); 2885 2886 // generate random number first, if we need to show passkey, otherwise send response 2887 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2888 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2889 break; 2890 } 2891 2892 /* fall through */ 2893 2894 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2895 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2896 2897 // start with initiator key dist flags 2898 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2899 2900 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2901 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2902 if (setup->sm_use_secure_connections){ 2903 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2904 } 2905 #endif 2906 // setup in response 2907 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); 2908 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); 2909 2910 // update key distribution after ENC was dropped 2911 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)); 2912 2913 if (setup->sm_use_secure_connections){ 2914 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2915 } else { 2916 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2917 } 2918 2919 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2920 sm_timeout_reset(connection); 2921 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2922 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2923 sm_trigger_user_response(connection); 2924 } 2925 return; 2926 #endif 2927 2928 case SM_PH2_SEND_PAIRING_RANDOM: { 2929 uint8_t buffer[17]; 2930 buffer[0] = SM_CODE_PAIRING_RANDOM; 2931 reverse_128(setup->sm_local_random, &buffer[1]); 2932 if (IS_RESPONDER(connection->sm_role)){ 2933 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2934 } else { 2935 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2936 } 2937 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2938 sm_timeout_reset(connection); 2939 break; 2940 } 2941 2942 case SM_PH2_C1_GET_ENC_A: 2943 // already busy? 2944 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2945 // calculate confirm using aes128 engine - step 1 2946 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); 2947 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2948 sm_aes128_state = SM_AES128_ACTIVE; 2949 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); 2950 break; 2951 2952 case SM_PH2_C1_GET_ENC_C: 2953 // already busy? 2954 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2955 // calculate m_confirm using aes128 engine - step 1 2956 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); 2957 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2958 sm_aes128_state = SM_AES128_ACTIVE; 2959 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); 2960 break; 2961 2962 case SM_PH2_CALC_STK: 2963 // already busy? 2964 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2965 // calculate STK 2966 if (IS_RESPONDER(connection->sm_role)){ 2967 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2968 } else { 2969 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2970 } 2971 connection->sm_engine_state = SM_PH2_W4_STK; 2972 sm_aes128_state = SM_AES128_ACTIVE; 2973 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); 2974 break; 2975 2976 case SM_PH3_Y_GET_ENC: 2977 // already busy? 2978 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2979 // PH3B2 - calculate Y from - enc 2980 2981 // dm helper (was sm_dm_r_prime) 2982 // r' = padding || r 2983 // r - 64 bit value 2984 memset(&sm_aes128_plaintext[0], 0, 8); 2985 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2986 2987 // Y = dm(DHK, Rand) 2988 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2989 sm_aes128_state = SM_AES128_ACTIVE; 2990 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); 2991 break; 2992 2993 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2994 uint8_t buffer[17]; 2995 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2996 reverse_128(setup->sm_local_confirm, &buffer[1]); 2997 if (IS_RESPONDER(connection->sm_role)){ 2998 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2999 } else { 3000 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3001 } 3002 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3003 sm_timeout_reset(connection); 3004 return; 3005 } 3006 #ifdef ENABLE_LE_PERIPHERAL 3007 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3008 sm_key_t stk_flipped; 3009 reverse_128(setup->sm_ltk, stk_flipped); 3010 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3011 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3012 return; 3013 } 3014 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3015 // allow to override LTK 3016 if (sm_get_ltk_callback != NULL){ 3017 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3018 } 3019 sm_key_t ltk_flipped; 3020 reverse_128(setup->sm_ltk, ltk_flipped); 3021 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3022 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3023 return; 3024 } 3025 3026 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3027 // already busy? 3028 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3029 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3030 3031 sm_reset_setup(); 3032 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3033 3034 sm_reencryption_started(connection); 3035 3036 // dm helper (was sm_dm_r_prime) 3037 // r' = padding || r 3038 // r - 64 bit value 3039 memset(&sm_aes128_plaintext[0], 0, 8); 3040 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3041 3042 // Y = dm(DHK, Rand) 3043 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3044 sm_aes128_state = SM_AES128_ACTIVE; 3045 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); 3046 return; 3047 #endif 3048 #ifdef ENABLE_LE_CENTRAL 3049 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3050 sm_key_t stk_flipped; 3051 reverse_128(setup->sm_ltk, stk_flipped); 3052 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3053 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3054 return; 3055 } 3056 #endif 3057 3058 case SM_PH3_DISTRIBUTE_KEYS: 3059 if (setup->sm_key_distribution_send_set != 0){ 3060 sm_run_distribute_keys(connection); 3061 return; 3062 } 3063 3064 // keys are sent 3065 if (IS_RESPONDER(connection->sm_role)){ 3066 // slave -> receive master keys if any 3067 if (sm_key_distribution_all_received()){ 3068 sm_key_distribution_handle_all_received(connection); 3069 sm_key_distribution_complete_responder(connection); 3070 // start CTKD right away 3071 continue; 3072 } else { 3073 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3074 } 3075 } else { 3076 sm_master_pairing_success(connection); 3077 } 3078 break; 3079 3080 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3081 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3082 // fill in sm setup (lite version of sm_init_setup) 3083 sm_reset_setup(); 3084 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3085 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3086 setup->sm_s_addr_type = connection->sm_own_addr_type; 3087 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3088 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3089 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3090 setup->sm_use_secure_connections = true; 3091 sm_ctkd_fetch_br_edr_link_key(connection); 3092 3093 // Enc Key and IRK if requested 3094 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3095 #ifdef ENABLE_LE_SIGNED_WRITE 3096 // Plus signing key if supported 3097 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3098 #endif 3099 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3100 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3101 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3102 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3103 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3104 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3105 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3106 3107 // set state and send pairing response 3108 sm_timeout_start(connection); 3109 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3110 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3111 break; 3112 3113 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3114 // fill in sm setup (lite version of sm_init_setup) 3115 sm_reset_setup(); 3116 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3117 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3118 setup->sm_s_addr_type = connection->sm_own_addr_type; 3119 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3120 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3121 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3122 setup->sm_use_secure_connections = true; 3123 sm_ctkd_fetch_br_edr_link_key(connection); 3124 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3125 3126 // Enc Key and IRK if requested 3127 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3128 #ifdef ENABLE_LE_SIGNED_WRITE 3129 // Plus signing key if supported 3130 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3131 #endif 3132 // drop flags not requested by initiator 3133 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3134 3135 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3136 // - the IO Capability field, 3137 // - the OOB data flag field, and 3138 // - all bits in the Auth Req field except the CT2 bit. 3139 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3140 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3141 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3142 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3143 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3144 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3145 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3146 3147 // configure key distribution, LTK is derived locally 3148 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3149 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3150 3151 // set state and send pairing response 3152 sm_timeout_start(connection); 3153 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3154 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3155 break; 3156 case SM_BR_EDR_DISTRIBUTE_KEYS: 3157 if (setup->sm_key_distribution_send_set != 0) { 3158 sm_run_distribute_keys(connection); 3159 return; 3160 } 3161 // keys are sent 3162 if (IS_RESPONDER(connection->sm_role)) { 3163 // responder -> receive master keys if there are any 3164 if (!sm_key_distribution_all_received()){ 3165 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3166 break; 3167 } 3168 } 3169 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3170 sm_ctkd_start_from_br_edr(connection); 3171 continue; 3172 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3173 if (!sm_cmac_ready()) break; 3174 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3175 h6_calculate_ilk_from_le_ltk(connection); 3176 break; 3177 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3178 if (!sm_cmac_ready()) break; 3179 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3180 h6_calculate_br_edr_link_key(connection); 3181 break; 3182 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3183 if (!sm_cmac_ready()) break; 3184 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3185 h7_calculate_ilk_from_le_ltk(connection); 3186 break; 3187 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3188 if (!sm_cmac_ready()) break; 3189 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3190 h6_calculate_ilk_from_br_edr(connection); 3191 break; 3192 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3193 if (!sm_cmac_ready()) break; 3194 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3195 h6_calculate_le_ltk(connection); 3196 break; 3197 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3198 if (!sm_cmac_ready()) break; 3199 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3200 h7_calculate_ilk_from_br_edr(connection); 3201 break; 3202 #endif 3203 3204 default: 3205 break; 3206 } 3207 3208 // check again if active connection was released 3209 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3210 } 3211 } 3212 3213 // sm_aes128_state stays active 3214 static void sm_handle_encryption_result_enc_a(void *arg){ 3215 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3216 sm_aes128_state = SM_AES128_IDLE; 3217 3218 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3219 if (connection == NULL) return; 3220 3221 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3222 sm_aes128_state = SM_AES128_ACTIVE; 3223 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); 3224 } 3225 3226 static void sm_handle_encryption_result_enc_b(void *arg){ 3227 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3228 sm_aes128_state = SM_AES128_IDLE; 3229 3230 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3231 if (connection == NULL) return; 3232 3233 log_info_key("c1!", setup->sm_local_confirm); 3234 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3235 sm_trigger_run(); 3236 } 3237 3238 // sm_aes128_state stays active 3239 static void sm_handle_encryption_result_enc_c(void *arg){ 3240 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3241 sm_aes128_state = SM_AES128_IDLE; 3242 3243 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3244 if (connection == NULL) return; 3245 3246 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3247 sm_aes128_state = SM_AES128_ACTIVE; 3248 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); 3249 } 3250 3251 static void sm_handle_encryption_result_enc_d(void * arg){ 3252 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3253 sm_aes128_state = SM_AES128_IDLE; 3254 3255 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3256 if (connection == NULL) return; 3257 3258 log_info_key("c1!", sm_aes128_ciphertext); 3259 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3260 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3261 sm_trigger_run(); 3262 return; 3263 } 3264 if (IS_RESPONDER(connection->sm_role)){ 3265 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3266 sm_trigger_run(); 3267 } else { 3268 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3269 sm_aes128_state = SM_AES128_ACTIVE; 3270 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); 3271 } 3272 } 3273 3274 static void sm_handle_encryption_result_enc_stk(void *arg){ 3275 sm_aes128_state = SM_AES128_IDLE; 3276 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3277 3278 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3279 if (connection == NULL) return; 3280 3281 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3282 log_info_key("stk", setup->sm_ltk); 3283 if (IS_RESPONDER(connection->sm_role)){ 3284 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3285 } else { 3286 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3287 } 3288 sm_trigger_run(); 3289 } 3290 3291 // sm_aes128_state stays active 3292 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3293 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3294 sm_aes128_state = SM_AES128_IDLE; 3295 3296 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3297 if (connection == NULL) return; 3298 3299 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3300 log_info_hex16("y", setup->sm_local_y); 3301 // PH3B3 - calculate EDIV 3302 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3303 log_info_hex16("ediv", setup->sm_local_ediv); 3304 // PH3B4 - calculate LTK - enc 3305 // LTK = d1(ER, DIV, 0)) 3306 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3307 sm_aes128_state = SM_AES128_ACTIVE; 3308 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); 3309 } 3310 3311 #ifdef ENABLE_LE_PERIPHERAL 3312 // sm_aes128_state stays active 3313 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3314 sm_aes128_state = SM_AES128_IDLE; 3315 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3316 3317 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3318 if (connection == NULL) return; 3319 3320 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3321 log_info_hex16("y", setup->sm_local_y); 3322 3323 // PH3B3 - calculate DIV 3324 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3325 log_info_hex16("ediv", setup->sm_local_ediv); 3326 // PH3B4 - calculate LTK - enc 3327 // LTK = d1(ER, DIV, 0)) 3328 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3329 sm_aes128_state = SM_AES128_ACTIVE; 3330 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); 3331 } 3332 #endif 3333 3334 // sm_aes128_state stays active 3335 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3336 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3337 sm_aes128_state = SM_AES128_IDLE; 3338 3339 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3340 if (connection == NULL) return; 3341 3342 log_info_key("ltk", setup->sm_ltk); 3343 // calc CSRK next 3344 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3345 sm_aes128_state = SM_AES128_ACTIVE; 3346 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); 3347 } 3348 3349 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3350 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3351 sm_aes128_state = SM_AES128_IDLE; 3352 3353 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3354 if (connection == NULL) return; 3355 3356 sm_aes128_state = SM_AES128_IDLE; 3357 log_info_key("csrk", setup->sm_local_csrk); 3358 if (setup->sm_key_distribution_send_set){ 3359 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3360 } else { 3361 // no keys to send, just continue 3362 if (IS_RESPONDER(connection->sm_role)){ 3363 if (sm_key_distribution_all_received()){ 3364 sm_key_distribution_handle_all_received(connection); 3365 sm_key_distribution_complete_responder(connection); 3366 } else { 3367 // slave -> receive master keys 3368 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3369 } 3370 } else { 3371 sm_key_distribution_complete_initiator(connection); 3372 } 3373 } 3374 sm_trigger_run(); 3375 } 3376 3377 #ifdef ENABLE_LE_PERIPHERAL 3378 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3379 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3380 sm_aes128_state = SM_AES128_IDLE; 3381 3382 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3383 if (connection == NULL) return; 3384 3385 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3386 log_info_key("ltk", setup->sm_ltk); 3387 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3388 sm_trigger_run(); 3389 } 3390 #endif 3391 3392 static void sm_handle_encryption_result_address_resolution(void *arg){ 3393 UNUSED(arg); 3394 sm_aes128_state = SM_AES128_IDLE; 3395 3396 sm_address_resolution_ah_calculation_active = 0; 3397 // compare calulated address against connecting device 3398 uint8_t * hash = &sm_aes128_ciphertext[13]; 3399 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3400 log_info("LE Device Lookup: matched resolvable private address"); 3401 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3402 sm_trigger_run(); 3403 return; 3404 } 3405 // no match, try next 3406 sm_address_resolution_test++; 3407 sm_trigger_run(); 3408 } 3409 3410 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3411 UNUSED(arg); 3412 sm_aes128_state = SM_AES128_IDLE; 3413 3414 log_info_key("irk", sm_persistent_irk); 3415 dkg_state = DKG_CALC_DHK; 3416 sm_trigger_run(); 3417 } 3418 3419 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3420 UNUSED(arg); 3421 sm_aes128_state = SM_AES128_IDLE; 3422 3423 log_info_key("dhk", sm_persistent_dhk); 3424 dkg_state = DKG_READY; 3425 sm_trigger_run(); 3426 } 3427 3428 static void sm_handle_encryption_result_rau(void *arg){ 3429 UNUSED(arg); 3430 sm_aes128_state = SM_AES128_IDLE; 3431 3432 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3433 rau_state = RAU_IDLE; 3434 hci_le_random_address_set(sm_random_address); 3435 3436 sm_trigger_run(); 3437 } 3438 3439 static void sm_handle_random_result_rau(void * arg){ 3440 UNUSED(arg); 3441 // non-resolvable vs. resolvable 3442 switch (gap_random_adress_type){ 3443 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3444 // resolvable: use random as prand and calc address hash 3445 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3446 sm_random_address[0u] &= 0x3fu; 3447 sm_random_address[0u] |= 0x40u; 3448 rau_state = RAU_GET_ENC; 3449 break; 3450 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3451 default: 3452 // "The two most significant bits of the address shall be equal to ‘0’"" 3453 sm_random_address[0u] &= 0x3fu; 3454 hci_le_random_address_set(sm_random_address); 3455 break; 3456 } 3457 sm_trigger_run(); 3458 } 3459 3460 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3461 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3462 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3463 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3464 if (connection == NULL) return; 3465 3466 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3467 sm_trigger_run(); 3468 } 3469 3470 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3471 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3472 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3473 if (connection == NULL) return; 3474 3475 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3476 sm_trigger_run(); 3477 } 3478 #endif 3479 3480 static void sm_handle_random_result_ph2_random(void * arg){ 3481 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3482 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3483 if (connection == NULL) return; 3484 3485 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3486 sm_trigger_run(); 3487 } 3488 3489 static void sm_handle_random_result_ph2_tk(void * arg){ 3490 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3491 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3492 if (connection == NULL) return; 3493 3494 sm_reset_tk(); 3495 uint32_t tk; 3496 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3497 // map random to 0-999999 without speding much cycles on a modulus operation 3498 tk = little_endian_read_32(sm_random_data,0); 3499 tk = tk & 0xfffff; // 1048575 3500 if (tk >= 999999u){ 3501 tk = tk - 999999u; 3502 } 3503 } else { 3504 // override with pre-defined passkey 3505 tk = sm_fixed_passkey_in_display_role; 3506 } 3507 big_endian_store_32(setup->sm_tk, 12, tk); 3508 if (IS_RESPONDER(connection->sm_role)){ 3509 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3510 } else { 3511 if (setup->sm_use_secure_connections){ 3512 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3513 } else { 3514 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3515 sm_trigger_user_response(connection); 3516 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3517 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3518 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); 3519 } 3520 } 3521 } 3522 sm_trigger_run(); 3523 } 3524 3525 static void sm_handle_random_result_ph3_div(void * arg){ 3526 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3527 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3528 if (connection == NULL) return; 3529 3530 // use 16 bit from random value as div 3531 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3532 log_info_hex16("div", setup->sm_local_div); 3533 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3534 sm_trigger_run(); 3535 } 3536 3537 static void sm_handle_random_result_ph3_random(void * arg){ 3538 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3539 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3540 if (connection == NULL) return; 3541 3542 reverse_64(sm_random_data, setup->sm_local_rand); 3543 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3544 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3545 // no db for authenticated flag hack: store flag in bit 4 of LSB 3546 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3547 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3548 } 3549 static void sm_validate_er_ir(void){ 3550 // warn about default ER/IR 3551 bool warning = false; 3552 if (sm_ir_is_default()){ 3553 warning = true; 3554 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3555 } 3556 if (sm_er_is_default()){ 3557 warning = true; 3558 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3559 } 3560 if (warning) { 3561 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3562 } 3563 } 3564 3565 static void sm_handle_random_result_ir(void *arg){ 3566 sm_persistent_keys_random_active = false; 3567 if (arg != NULL){ 3568 // key generated, store in tlv 3569 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3570 log_info("Generated IR key. Store in TLV status: %d", status); 3571 UNUSED(status); 3572 } 3573 log_info_key("IR", sm_persistent_ir); 3574 dkg_state = DKG_CALC_IRK; 3575 3576 if (test_use_fixed_local_irk){ 3577 log_info_key("IRK", sm_persistent_irk); 3578 dkg_state = DKG_CALC_DHK; 3579 } 3580 3581 sm_trigger_run(); 3582 } 3583 3584 static void sm_handle_random_result_er(void *arg){ 3585 sm_persistent_keys_random_active = false; 3586 if (arg != 0){ 3587 // key generated, store in tlv 3588 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3589 log_info("Generated ER key. Store in TLV status: %d", status); 3590 UNUSED(status); 3591 } 3592 log_info_key("ER", sm_persistent_er); 3593 3594 // try load ir 3595 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3596 if (key_size == 16){ 3597 // ok, let's continue 3598 log_info("IR from TLV"); 3599 sm_handle_random_result_ir( NULL ); 3600 } else { 3601 // invalid, generate new random one 3602 sm_persistent_keys_random_active = true; 3603 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3604 } 3605 } 3606 3607 static void sm_connection_init(sm_connection_t * sm_conn, hci_con_handle_t con_handle, uint8_t role, uint8_t addr_type, bd_addr_t address){ 3608 3609 // connection info 3610 sm_conn->sm_handle = con_handle; 3611 sm_conn->sm_role = role; 3612 sm_conn->sm_peer_addr_type = addr_type; 3613 memcpy(sm_conn->sm_peer_address, address, 6); 3614 3615 // security properties 3616 sm_conn->sm_connection_encrypted = 0; 3617 sm_conn->sm_connection_authenticated = 0; 3618 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3619 sm_conn->sm_le_db_index = -1; 3620 sm_conn->sm_reencryption_active = false; 3621 3622 // prepare CSRK lookup (does not involve setup) 3623 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3624 3625 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3626 } 3627 3628 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3629 3630 UNUSED(channel); // ok: there is no channel 3631 UNUSED(size); // ok: fixed format HCI events 3632 3633 sm_connection_t * sm_conn; 3634 hci_con_handle_t con_handle; 3635 uint8_t status; 3636 bd_addr_t addr; 3637 3638 switch (packet_type) { 3639 3640 case HCI_EVENT_PACKET: 3641 switch (hci_event_packet_get_type(packet)) { 3642 3643 case BTSTACK_EVENT_STATE: 3644 // bt stack activated, get started 3645 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3646 log_info("HCI Working!"); 3647 3648 // setup IR/ER with TLV 3649 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3650 if (sm_tlv_impl != NULL){ 3651 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3652 if (key_size == 16){ 3653 // ok, let's continue 3654 log_info("ER from TLV"); 3655 sm_handle_random_result_er( NULL ); 3656 } else { 3657 // invalid, generate random one 3658 sm_persistent_keys_random_active = true; 3659 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3660 } 3661 } else { 3662 sm_validate_er_ir(); 3663 dkg_state = DKG_CALC_IRK; 3664 3665 if (test_use_fixed_local_irk){ 3666 log_info_key("IRK", sm_persistent_irk); 3667 dkg_state = DKG_CALC_DHK; 3668 } 3669 } 3670 3671 // restart random address updates after power cycle 3672 gap_random_address_set_mode(gap_random_adress_type); 3673 } 3674 break; 3675 3676 #ifdef ENABLE_CLASSIC 3677 case HCI_EVENT_CONNECTION_COMPLETE: 3678 // ignore if connection failed 3679 if (hci_event_connection_complete_get_status(packet)) return; 3680 3681 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3682 sm_conn = sm_get_connection_for_handle(con_handle); 3683 if (!sm_conn) break; 3684 3685 hci_event_connection_complete_get_bd_addr(packet, addr); 3686 sm_connection_init(sm_conn, 3687 con_handle, 3688 (uint8_t) gap_get_role(con_handle), 3689 BD_ADDR_TYPE_LE_PUBLIC, 3690 addr); 3691 // classic connection corresponds to public le address 3692 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3693 gap_local_bd_addr(sm_conn->sm_own_address); 3694 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3695 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3696 break; 3697 #endif 3698 3699 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3700 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3701 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3702 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3703 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3704 if (sm_conn == NULL) break; 3705 sm_conn->sm_pairing_requested = 1; 3706 break; 3707 #endif 3708 3709 case HCI_EVENT_LE_META: 3710 switch (packet[2]) { 3711 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3712 // ignore if connection failed 3713 if (packet[3]) return; 3714 3715 con_handle = little_endian_read_16(packet, 4); 3716 sm_conn = sm_get_connection_for_handle(con_handle); 3717 if (!sm_conn) break; 3718 3719 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3720 sm_connection_init(sm_conn, 3721 con_handle, 3722 hci_subevent_le_connection_complete_get_role(packet), 3723 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3724 addr); 3725 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3726 3727 // track our addr used for this connection and set state 3728 #ifdef ENABLE_LE_CENTRAL 3729 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3730 // responder - use own address from advertisements 3731 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3732 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3733 } 3734 #endif 3735 #ifdef ENABLE_LE_CENTRAL 3736 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3737 // initiator - use own address from create connection 3738 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3739 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3740 } 3741 #endif 3742 break; 3743 3744 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3745 con_handle = little_endian_read_16(packet, 3); 3746 sm_conn = sm_get_connection_for_handle(con_handle); 3747 if (!sm_conn) break; 3748 3749 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3750 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3751 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3752 break; 3753 } 3754 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3755 // PH2 SEND LTK as we need to exchange keys in PH3 3756 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3757 break; 3758 } 3759 3760 // store rand and ediv 3761 reverse_64(&packet[5], sm_conn->sm_local_rand); 3762 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3763 3764 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3765 // potentially stored LTK is from the master 3766 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3767 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3768 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3769 break; 3770 } 3771 // additionally check if remote is in LE Device DB if requested 3772 switch(sm_conn->sm_irk_lookup_state){ 3773 case IRK_LOOKUP_FAILED: 3774 log_info("LTK Request: device not in device db"); 3775 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3776 break; 3777 case IRK_LOOKUP_SUCCEEDED: 3778 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3779 break; 3780 default: 3781 // wait for irk look doen 3782 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3783 break; 3784 } 3785 break; 3786 } 3787 3788 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3789 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3790 #else 3791 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3792 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3793 #endif 3794 break; 3795 3796 default: 3797 break; 3798 } 3799 break; 3800 3801 case HCI_EVENT_ENCRYPTION_CHANGE: 3802 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3803 sm_conn = sm_get_connection_for_handle(con_handle); 3804 if (!sm_conn) break; 3805 3806 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3807 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3808 sm_conn->sm_actual_encryption_key_size); 3809 log_info("event handler, state %u", sm_conn->sm_engine_state); 3810 3811 switch (sm_conn->sm_engine_state){ 3812 3813 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3814 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3815 if (sm_conn->sm_connection_encrypted) { 3816 status = ERROR_CODE_SUCCESS; 3817 if (sm_conn->sm_role){ 3818 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3819 } else { 3820 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3821 } 3822 } else { 3823 status = hci_event_encryption_change_get_status(packet); 3824 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3825 // also, gap_reconnect_security_setup_active will return true 3826 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3827 } 3828 3829 // emit re-encryption complete 3830 sm_reencryption_complete(sm_conn, status); 3831 3832 // notify client, if pairing was requested before 3833 if (sm_conn->sm_pairing_requested){ 3834 sm_conn->sm_pairing_requested = 0; 3835 sm_pairing_complete(sm_conn, status, 0); 3836 } 3837 3838 sm_done_for_handle(sm_conn->sm_handle); 3839 break; 3840 3841 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3842 if (!sm_conn->sm_connection_encrypted) break; 3843 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3844 if (IS_RESPONDER(sm_conn->sm_role)){ 3845 // slave 3846 if (setup->sm_use_secure_connections){ 3847 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3848 } else { 3849 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); 3850 } 3851 } else { 3852 // master 3853 if (sm_key_distribution_all_received()){ 3854 // skip receiving keys as there are none 3855 sm_key_distribution_handle_all_received(sm_conn); 3856 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); 3857 } else { 3858 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3859 } 3860 } 3861 break; 3862 3863 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3864 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3865 if (sm_conn->sm_connection_encrypted != 2) break; 3866 // prepare for pairing request 3867 if (IS_RESPONDER(sm_conn->sm_role)){ 3868 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3869 } else if (sm_conn->sm_pairing_requested){ 3870 // only send LE pairing request after BR/EDR SSP 3871 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3872 } 3873 break; 3874 #endif 3875 default: 3876 break; 3877 } 3878 break; 3879 3880 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3881 con_handle = little_endian_read_16(packet, 3); 3882 sm_conn = sm_get_connection_for_handle(con_handle); 3883 if (!sm_conn) break; 3884 3885 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3886 log_info("event handler, state %u", sm_conn->sm_engine_state); 3887 // continue if part of initial pairing 3888 switch (sm_conn->sm_engine_state){ 3889 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3890 if (sm_conn->sm_role){ 3891 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3892 } else { 3893 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3894 } 3895 sm_done_for_handle(sm_conn->sm_handle); 3896 break; 3897 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3898 if (IS_RESPONDER(sm_conn->sm_role)){ 3899 // slave 3900 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); 3901 } else { 3902 // master 3903 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3904 } 3905 break; 3906 default: 3907 break; 3908 } 3909 break; 3910 3911 3912 case HCI_EVENT_DISCONNECTION_COMPLETE: 3913 con_handle = little_endian_read_16(packet, 3); 3914 sm_done_for_handle(con_handle); 3915 sm_conn = sm_get_connection_for_handle(con_handle); 3916 if (!sm_conn) break; 3917 3918 // pairing failed, if it was ongoing 3919 switch (sm_conn->sm_engine_state){ 3920 case SM_GENERAL_IDLE: 3921 case SM_INITIATOR_CONNECTED: 3922 case SM_RESPONDER_IDLE: 3923 break; 3924 default: 3925 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3926 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3927 break; 3928 } 3929 3930 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3931 sm_conn->sm_handle = 0; 3932 break; 3933 3934 case HCI_EVENT_COMMAND_COMPLETE: 3935 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)) { 3936 // set local addr for le device db 3937 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3938 le_device_db_set_local_bd_addr(addr); 3939 } 3940 break; 3941 default: 3942 break; 3943 } 3944 break; 3945 default: 3946 break; 3947 } 3948 3949 sm_run(); 3950 } 3951 3952 static inline int sm_calc_actual_encryption_key_size(int other){ 3953 if (other < sm_min_encryption_key_size) return 0; 3954 if (other < sm_max_encryption_key_size) return other; 3955 return sm_max_encryption_key_size; 3956 } 3957 3958 3959 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3960 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3961 switch (method){ 3962 case JUST_WORKS: 3963 case NUMERIC_COMPARISON: 3964 return 1; 3965 default: 3966 return 0; 3967 } 3968 } 3969 // responder 3970 3971 static int sm_passkey_used(stk_generation_method_t method){ 3972 switch (method){ 3973 case PK_RESP_INPUT: 3974 return 1; 3975 default: 3976 return 0; 3977 } 3978 } 3979 3980 static int sm_passkey_entry(stk_generation_method_t method){ 3981 switch (method){ 3982 case PK_RESP_INPUT: 3983 case PK_INIT_INPUT: 3984 case PK_BOTH_INPUT: 3985 return 1; 3986 default: 3987 return 0; 3988 } 3989 } 3990 3991 #endif 3992 3993 /** 3994 * @return ok 3995 */ 3996 static int sm_validate_stk_generation_method(void){ 3997 // check if STK generation method is acceptable by client 3998 switch (setup->sm_stk_generation_method){ 3999 case JUST_WORKS: 4000 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4001 case PK_RESP_INPUT: 4002 case PK_INIT_INPUT: 4003 case PK_BOTH_INPUT: 4004 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4005 case OOB: 4006 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4007 case NUMERIC_COMPARISON: 4008 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4009 default: 4010 return 0; 4011 } 4012 } 4013 4014 #ifdef ENABLE_LE_CENTRAL 4015 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4016 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4017 if (sm_sc_only_mode){ 4018 uint8_t auth_req = packet[1]; 4019 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4020 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4021 return; 4022 } 4023 } 4024 #else 4025 UNUSED(packet); 4026 #endif 4027 4028 int have_ltk; 4029 uint8_t ltk[16]; 4030 4031 // IRK complete? 4032 switch (sm_conn->sm_irk_lookup_state){ 4033 case IRK_LOOKUP_FAILED: 4034 // start pairing 4035 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4036 break; 4037 case IRK_LOOKUP_SUCCEEDED: 4038 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4039 have_ltk = !sm_is_null_key(ltk); 4040 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4041 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4042 // start re-encrypt if we have LTK and the connection is not already encrypted 4043 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4044 } else { 4045 // start pairing 4046 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4047 } 4048 break; 4049 default: 4050 // otherwise, store security request 4051 sm_conn->sm_security_request_received = 1; 4052 break; 4053 } 4054 } 4055 #endif 4056 4057 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4058 4059 // size of complete sm_pdu used to validate input 4060 static const uint8_t sm_pdu_size[] = { 4061 0, // 0x00 invalid opcode 4062 7, // 0x01 pairing request 4063 7, // 0x02 pairing response 4064 17, // 0x03 pairing confirm 4065 17, // 0x04 pairing random 4066 2, // 0x05 pairing failed 4067 17, // 0x06 encryption information 4068 11, // 0x07 master identification 4069 17, // 0x08 identification information 4070 8, // 0x09 identify address information 4071 17, // 0x0a signing information 4072 2, // 0x0b security request 4073 65, // 0x0c pairing public key 4074 17, // 0x0d pairing dhk check 4075 2, // 0x0e keypress notification 4076 }; 4077 4078 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4079 sm_run(); 4080 } 4081 4082 if (packet_type != SM_DATA_PACKET) return; 4083 if (size == 0u) return; 4084 4085 uint8_t sm_pdu_code = packet[0]; 4086 4087 // validate pdu size 4088 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 4089 if (sm_pdu_size[sm_pdu_code] != size) return; 4090 4091 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4092 if (!sm_conn) return; 4093 4094 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4095 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4096 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4097 sm_done_for_handle(con_handle); 4098 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4099 return; 4100 } 4101 4102 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4103 4104 int err; 4105 UNUSED(err); 4106 4107 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4108 uint8_t buffer[5]; 4109 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4110 buffer[1] = 3; 4111 little_endian_store_16(buffer, 2, con_handle); 4112 buffer[4] = packet[1]; 4113 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4114 return; 4115 } 4116 4117 switch (sm_conn->sm_engine_state){ 4118 4119 // a sm timeout requires a new physical connection 4120 case SM_GENERAL_TIMEOUT: 4121 return; 4122 4123 #ifdef ENABLE_LE_CENTRAL 4124 4125 // Initiator 4126 case SM_INITIATOR_CONNECTED: 4127 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4128 sm_pdu_received_in_wrong_state(sm_conn); 4129 break; 4130 } 4131 sm_initiator_connected_handle_security_request(sm_conn, packet); 4132 break; 4133 4134 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4135 // Core 5, Vol 3, Part H, 2.4.6: 4136 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4137 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4138 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4139 log_info("Ignoring Security Request"); 4140 break; 4141 } 4142 4143 // all other pdus are incorrect 4144 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4145 sm_pdu_received_in_wrong_state(sm_conn); 4146 break; 4147 } 4148 4149 // store pairing request 4150 (void)memcpy(&setup->sm_s_pres, packet, 4151 sizeof(sm_pairing_packet_t)); 4152 err = sm_stk_generation_init(sm_conn); 4153 4154 #ifdef ENABLE_TESTING_SUPPORT 4155 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4156 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4157 err = test_pairing_failure; 4158 } 4159 #endif 4160 4161 if (err != 0){ 4162 sm_pairing_error(sm_conn, err); 4163 break; 4164 } 4165 4166 // generate random number first, if we need to show passkey 4167 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4168 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); 4169 break; 4170 } 4171 4172 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4173 if (setup->sm_use_secure_connections){ 4174 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4175 if (setup->sm_stk_generation_method == JUST_WORKS){ 4176 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4177 sm_trigger_user_response(sm_conn); 4178 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4179 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4180 } 4181 } else { 4182 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4183 } 4184 break; 4185 } 4186 #endif 4187 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4188 sm_trigger_user_response(sm_conn); 4189 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4190 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4191 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); 4192 } 4193 break; 4194 4195 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4196 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4197 sm_pdu_received_in_wrong_state(sm_conn); 4198 break; 4199 } 4200 4201 // store s_confirm 4202 reverse_128(&packet[1], setup->sm_peer_confirm); 4203 4204 // abort if s_confirm matches m_confirm 4205 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4206 sm_pdu_received_in_wrong_state(sm_conn); 4207 break; 4208 } 4209 4210 #ifdef ENABLE_TESTING_SUPPORT 4211 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4212 log_info("testing_support: reset confirm value"); 4213 memset(setup->sm_peer_confirm, 0, 16); 4214 } 4215 #endif 4216 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4217 break; 4218 4219 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4220 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4221 sm_pdu_received_in_wrong_state(sm_conn); 4222 break;; 4223 } 4224 4225 // received random value 4226 reverse_128(&packet[1], setup->sm_peer_random); 4227 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4228 break; 4229 #endif 4230 4231 #ifdef ENABLE_LE_PERIPHERAL 4232 // Responder 4233 case SM_RESPONDER_IDLE: 4234 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4235 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4236 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4237 sm_pdu_received_in_wrong_state(sm_conn); 4238 break;; 4239 } 4240 4241 // store pairing request 4242 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4243 4244 // check if IRK completed 4245 switch (sm_conn->sm_irk_lookup_state){ 4246 case IRK_LOOKUP_SUCCEEDED: 4247 case IRK_LOOKUP_FAILED: 4248 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4249 break; 4250 default: 4251 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4252 break; 4253 } 4254 break; 4255 #endif 4256 4257 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4258 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4259 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4260 sm_pdu_received_in_wrong_state(sm_conn); 4261 break; 4262 } 4263 4264 // store public key for DH Key calculation 4265 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4266 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4267 4268 // CVE-2020-26558: abort pairing if remote uses the same public key 4269 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4270 log_info("Remote PK matches ours"); 4271 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4272 break; 4273 } 4274 4275 // validate public key 4276 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4277 if (err != 0){ 4278 log_info("sm: peer public key invalid %x", err); 4279 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4280 break; 4281 } 4282 4283 // start calculating dhkey 4284 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); 4285 4286 4287 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4288 if (IS_RESPONDER(sm_conn->sm_role)){ 4289 // responder 4290 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4291 } else { 4292 // initiator 4293 // stk generation method 4294 // passkey entry: notify app to show passkey or to request passkey 4295 switch (setup->sm_stk_generation_method){ 4296 case JUST_WORKS: 4297 case NUMERIC_COMPARISON: 4298 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4299 break; 4300 case PK_RESP_INPUT: 4301 sm_sc_start_calculating_local_confirm(sm_conn); 4302 break; 4303 case PK_INIT_INPUT: 4304 case PK_BOTH_INPUT: 4305 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4306 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4307 break; 4308 } 4309 sm_sc_start_calculating_local_confirm(sm_conn); 4310 break; 4311 case OOB: 4312 // generate Nx 4313 log_info("Generate Na"); 4314 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); 4315 break; 4316 default: 4317 btstack_assert(false); 4318 break; 4319 } 4320 } 4321 break; 4322 4323 case SM_SC_W4_CONFIRMATION: 4324 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4325 sm_pdu_received_in_wrong_state(sm_conn); 4326 break; 4327 } 4328 // received confirm value 4329 reverse_128(&packet[1], setup->sm_peer_confirm); 4330 4331 #ifdef ENABLE_TESTING_SUPPORT 4332 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4333 log_info("testing_support: reset confirm value"); 4334 memset(setup->sm_peer_confirm, 0, 16); 4335 } 4336 #endif 4337 if (IS_RESPONDER(sm_conn->sm_role)){ 4338 // responder 4339 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4340 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4341 // still waiting for passkey 4342 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4343 break; 4344 } 4345 } 4346 sm_sc_start_calculating_local_confirm(sm_conn); 4347 } else { 4348 // initiator 4349 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4350 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); 4351 } else { 4352 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4353 } 4354 } 4355 break; 4356 4357 case SM_SC_W4_PAIRING_RANDOM: 4358 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4359 sm_pdu_received_in_wrong_state(sm_conn); 4360 break; 4361 } 4362 4363 // received random value 4364 reverse_128(&packet[1], setup->sm_peer_nonce); 4365 4366 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4367 // only check for JUST WORK/NC in initiator role OR passkey entry 4368 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4369 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4370 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4371 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4372 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4373 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4374 break; 4375 } 4376 4377 // OOB 4378 if (setup->sm_stk_generation_method == OOB){ 4379 4380 // setup local random, set to zero if remote did not receive our data 4381 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4382 if (IS_RESPONDER(sm_conn->sm_role)){ 4383 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4384 log_info("Reset rb as A does not have OOB data"); 4385 memset(setup->sm_rb, 0, 16); 4386 } else { 4387 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4388 log_info("Use stored rb"); 4389 log_info_hexdump(setup->sm_rb, 16); 4390 } 4391 } else { 4392 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4393 log_info("Reset ra as B does not have OOB data"); 4394 memset(setup->sm_ra, 0, 16); 4395 } else { 4396 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4397 log_info("Use stored ra"); 4398 log_info_hexdump(setup->sm_ra, 16); 4399 } 4400 } 4401 4402 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4403 if (setup->sm_have_oob_data){ 4404 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4405 break; 4406 } 4407 } 4408 4409 // TODO: we only get here for Responder role with JW/NC 4410 sm_sc_state_after_receiving_random(sm_conn); 4411 break; 4412 4413 case SM_SC_W2_CALCULATE_G2: 4414 case SM_SC_W4_CALCULATE_G2: 4415 case SM_SC_W4_CALCULATE_DHKEY: 4416 case SM_SC_W2_CALCULATE_F5_SALT: 4417 case SM_SC_W4_CALCULATE_F5_SALT: 4418 case SM_SC_W2_CALCULATE_F5_MACKEY: 4419 case SM_SC_W4_CALCULATE_F5_MACKEY: 4420 case SM_SC_W2_CALCULATE_F5_LTK: 4421 case SM_SC_W4_CALCULATE_F5_LTK: 4422 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4423 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4424 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4425 case SM_SC_W4_USER_RESPONSE: 4426 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4427 sm_pdu_received_in_wrong_state(sm_conn); 4428 break; 4429 } 4430 // store DHKey Check 4431 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4432 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4433 4434 // have we been only waiting for dhkey check command? 4435 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4436 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4437 } 4438 break; 4439 #endif 4440 4441 #ifdef ENABLE_LE_PERIPHERAL 4442 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4443 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4444 sm_pdu_received_in_wrong_state(sm_conn); 4445 break; 4446 } 4447 4448 // received confirm value 4449 reverse_128(&packet[1], setup->sm_peer_confirm); 4450 4451 #ifdef ENABLE_TESTING_SUPPORT 4452 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4453 log_info("testing_support: reset confirm value"); 4454 memset(setup->sm_peer_confirm, 0, 16); 4455 } 4456 #endif 4457 // notify client to hide shown passkey 4458 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4459 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4460 } 4461 4462 // handle user cancel pairing? 4463 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4464 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4465 break; 4466 } 4467 4468 // wait for user action? 4469 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4470 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4471 break; 4472 } 4473 4474 // calculate and send local_confirm 4475 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); 4476 break; 4477 4478 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4479 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4480 sm_pdu_received_in_wrong_state(sm_conn); 4481 break;; 4482 } 4483 4484 // received random value 4485 reverse_128(&packet[1], setup->sm_peer_random); 4486 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4487 break; 4488 #endif 4489 4490 case SM_PH3_RECEIVE_KEYS: 4491 switch(sm_pdu_code){ 4492 case SM_CODE_ENCRYPTION_INFORMATION: 4493 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4494 reverse_128(&packet[1], setup->sm_peer_ltk); 4495 break; 4496 4497 case SM_CODE_MASTER_IDENTIFICATION: 4498 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4499 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4500 reverse_64(&packet[3], setup->sm_peer_rand); 4501 break; 4502 4503 case SM_CODE_IDENTITY_INFORMATION: 4504 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4505 reverse_128(&packet[1], setup->sm_peer_irk); 4506 break; 4507 4508 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4509 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4510 setup->sm_peer_addr_type = packet[1]; 4511 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4512 break; 4513 4514 case SM_CODE_SIGNING_INFORMATION: 4515 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4516 reverse_128(&packet[1], setup->sm_peer_csrk); 4517 break; 4518 default: 4519 // Unexpected PDU 4520 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4521 break; 4522 } 4523 // done with key distribution? 4524 if (sm_key_distribution_all_received()){ 4525 4526 sm_key_distribution_handle_all_received(sm_conn); 4527 4528 if (IS_RESPONDER(sm_conn->sm_role)){ 4529 sm_key_distribution_complete_responder(sm_conn); 4530 } else { 4531 if (setup->sm_use_secure_connections){ 4532 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4533 } else { 4534 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); 4535 } 4536 } 4537 } 4538 break; 4539 4540 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4541 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4542 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4543 sm_pdu_received_in_wrong_state(sm_conn); 4544 break; 4545 } 4546 // store pairing response 4547 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4548 4549 // validate encryption key size 4550 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres)); 4551 // SC Only mandates 128 bit key size 4552 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4553 sm_conn->sm_actual_encryption_key_size = 0; 4554 } 4555 if (sm_conn->sm_actual_encryption_key_size == 0){ 4556 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4557 break; 4558 } 4559 4560 // prepare key exchange, LTK is derived locally 4561 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4562 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4563 4564 // skip receive if there are none 4565 if (sm_key_distribution_all_received()){ 4566 // distribute keys in run handles 'no keys to send' 4567 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4568 } else { 4569 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4570 } 4571 break; 4572 4573 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4574 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4575 sm_pdu_received_in_wrong_state(sm_conn); 4576 break; 4577 } 4578 // store pairing request 4579 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4580 // validate encryption key size 4581 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq)); 4582 // SC Only mandates 128 bit key size 4583 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4584 sm_conn->sm_actual_encryption_key_size = 0; 4585 } 4586 if (sm_conn->sm_actual_encryption_key_size == 0){ 4587 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4588 break; 4589 } 4590 // trigger response 4591 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4592 break; 4593 4594 case SM_BR_EDR_RECEIVE_KEYS: 4595 switch(sm_pdu_code){ 4596 case SM_CODE_IDENTITY_INFORMATION: 4597 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4598 reverse_128(&packet[1], setup->sm_peer_irk); 4599 break; 4600 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4601 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4602 setup->sm_peer_addr_type = packet[1]; 4603 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4604 break; 4605 case SM_CODE_SIGNING_INFORMATION: 4606 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4607 reverse_128(&packet[1], setup->sm_peer_csrk); 4608 break; 4609 default: 4610 // Unexpected PDU 4611 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4612 break; 4613 } 4614 4615 // all keys received 4616 if (sm_key_distribution_all_received()){ 4617 if (IS_RESPONDER(sm_conn->sm_role)){ 4618 // responder -> keys exchanged, derive LE LTK 4619 sm_ctkd_start_from_br_edr(sm_conn); 4620 } else { 4621 // initiator -> send our keys if any 4622 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4623 } 4624 } 4625 break; 4626 #endif 4627 4628 default: 4629 // Unexpected PDU 4630 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4631 sm_pdu_received_in_wrong_state(sm_conn); 4632 break; 4633 } 4634 4635 // try to send next pdu 4636 sm_trigger_run(); 4637 } 4638 4639 // Security Manager Client API 4640 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4641 sm_get_oob_data = get_oob_data_callback; 4642 } 4643 4644 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)){ 4645 sm_get_sc_oob_data = get_sc_oob_data_callback; 4646 } 4647 4648 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)){ 4649 sm_get_ltk_callback = get_ltk_callback; 4650 } 4651 4652 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4653 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4654 } 4655 4656 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4657 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4658 } 4659 4660 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4661 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4662 } 4663 4664 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4665 sm_min_encryption_key_size = min_size; 4666 sm_max_encryption_key_size = max_size; 4667 } 4668 4669 void sm_set_authentication_requirements(uint8_t auth_req){ 4670 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4671 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4672 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4673 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4674 } 4675 #endif 4676 sm_auth_req = auth_req; 4677 } 4678 4679 void sm_set_io_capabilities(io_capability_t io_capability){ 4680 sm_io_capabilities = io_capability; 4681 } 4682 4683 #ifdef ENABLE_LE_PERIPHERAL 4684 void sm_set_request_security(int enable){ 4685 sm_slave_request_security = enable; 4686 } 4687 #endif 4688 4689 void sm_set_er(sm_key_t er){ 4690 (void)memcpy(sm_persistent_er, er, 16); 4691 } 4692 4693 void sm_set_ir(sm_key_t ir){ 4694 (void)memcpy(sm_persistent_ir, ir, 16); 4695 } 4696 4697 // Testing support only 4698 void sm_test_set_irk(sm_key_t irk){ 4699 (void)memcpy(sm_persistent_irk, irk, 16); 4700 dkg_state = DKG_CALC_DHK; 4701 test_use_fixed_local_irk = true; 4702 } 4703 4704 void sm_test_use_fixed_local_csrk(void){ 4705 test_use_fixed_local_csrk = true; 4706 } 4707 4708 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4709 static void sm_ec_generated(void * arg){ 4710 UNUSED(arg); 4711 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4712 // trigger pairing if pending for ec key 4713 sm_trigger_run(); 4714 } 4715 static void sm_ec_generate_new_key(void){ 4716 log_info("sm: generate new ec key"); 4717 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4718 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4719 } 4720 #endif 4721 4722 #ifdef ENABLE_TESTING_SUPPORT 4723 void sm_test_set_pairing_failure(int reason){ 4724 test_pairing_failure = reason; 4725 } 4726 #endif 4727 4728 void sm_init(void){ 4729 4730 if (sm_initialized) return; 4731 4732 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4733 sm_er_ir_set_default(); 4734 4735 // defaults 4736 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4737 | SM_STK_GENERATION_METHOD_OOB 4738 | SM_STK_GENERATION_METHOD_PASSKEY 4739 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4740 4741 sm_max_encryption_key_size = 16; 4742 sm_min_encryption_key_size = 7; 4743 4744 sm_fixed_passkey_in_display_role = 0xffffffffU; 4745 sm_reconstruct_ltk_without_le_device_db_entry = true; 4746 4747 #ifdef USE_CMAC_ENGINE 4748 sm_cmac_active = 0; 4749 #endif 4750 dkg_state = DKG_W4_WORKING; 4751 rau_state = RAU_IDLE; 4752 sm_aes128_state = SM_AES128_IDLE; 4753 sm_address_resolution_test = -1; // no private address to resolve yet 4754 sm_address_resolution_ah_calculation_active = 0; 4755 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4756 sm_address_resolution_general_queue = NULL; 4757 4758 gap_random_adress_update_period = 15 * 60 * 1000L; 4759 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4760 4761 test_use_fixed_local_csrk = false; 4762 4763 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4764 4765 // register for HCI Events from HCI 4766 hci_event_callback_registration.callback = &sm_event_packet_handler; 4767 hci_add_event_handler(&hci_event_callback_registration); 4768 4769 // 4770 btstack_crypto_init(); 4771 4772 // init le_device_db 4773 le_device_db_init(); 4774 4775 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4776 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4777 4778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4779 sm_ec_generate_new_key(); 4780 #endif 4781 4782 sm_initialized = true; 4783 } 4784 4785 void sm_deinit(void){ 4786 sm_initialized = false; 4787 btstack_run_loop_remove_timer(&sm_run_timer); 4788 } 4789 4790 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4791 sm_fixed_passkey_in_display_role = passkey; 4792 } 4793 4794 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4795 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4796 } 4797 4798 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4799 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4800 if (!hci_con) return NULL; 4801 return &hci_con->sm_connection; 4802 } 4803 4804 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4805 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4806 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4807 if (!hci_con) return NULL; 4808 return &hci_con->sm_connection; 4809 } 4810 #endif 4811 4812 // @deprecated: map onto sm_request_pairing 4813 void sm_send_security_request(hci_con_handle_t con_handle){ 4814 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4815 if (!sm_conn) return; 4816 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4817 sm_request_pairing(con_handle); 4818 } 4819 4820 // request pairing 4821 void sm_request_pairing(hci_con_handle_t con_handle){ 4822 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4823 if (!sm_conn) return; // wrong connection 4824 4825 bool have_ltk; 4826 uint8_t ltk[16]; 4827 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4828 if (IS_RESPONDER(sm_conn->sm_role)){ 4829 switch (sm_conn->sm_engine_state){ 4830 case SM_GENERAL_IDLE: 4831 case SM_RESPONDER_IDLE: 4832 switch (sm_conn->sm_irk_lookup_state){ 4833 case IRK_LOOKUP_SUCCEEDED: 4834 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4835 have_ltk = !sm_is_null_key(ltk); 4836 log_info("have ltk %u", have_ltk); 4837 if (have_ltk){ 4838 sm_conn->sm_pairing_requested = 1; 4839 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4840 sm_reencryption_started(sm_conn); 4841 break; 4842 } 4843 /* fall through */ 4844 4845 case IRK_LOOKUP_FAILED: 4846 sm_conn->sm_pairing_requested = 1; 4847 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4848 sm_pairing_started(sm_conn); 4849 break; 4850 default: 4851 log_info("irk lookup pending"); 4852 sm_conn->sm_pairing_requested = 1; 4853 break; 4854 } 4855 break; 4856 default: 4857 break; 4858 } 4859 } else { 4860 // used as a trigger to start central/master/initiator security procedures 4861 switch (sm_conn->sm_engine_state){ 4862 case SM_INITIATOR_CONNECTED: 4863 switch (sm_conn->sm_irk_lookup_state){ 4864 case IRK_LOOKUP_SUCCEEDED: 4865 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4866 have_ltk = !sm_is_null_key(ltk); 4867 log_info("have ltk %u", have_ltk); 4868 if (have_ltk){ 4869 sm_conn->sm_pairing_requested = 1; 4870 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4871 break; 4872 } 4873 /* fall through */ 4874 4875 case IRK_LOOKUP_FAILED: 4876 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4877 break; 4878 default: 4879 log_info("irk lookup pending"); 4880 sm_conn->sm_pairing_requested = 1; 4881 break; 4882 } 4883 break; 4884 case SM_GENERAL_REENCRYPTION_FAILED: 4885 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4886 break; 4887 case SM_GENERAL_IDLE: 4888 sm_conn->sm_pairing_requested = 1; 4889 break; 4890 default: 4891 break; 4892 } 4893 } 4894 sm_trigger_run(); 4895 } 4896 4897 // called by client app on authorization request 4898 void sm_authorization_decline(hci_con_handle_t con_handle){ 4899 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4900 if (!sm_conn) return; // wrong connection 4901 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4902 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4903 } 4904 4905 void sm_authorization_grant(hci_con_handle_t con_handle){ 4906 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4907 if (!sm_conn) return; // wrong connection 4908 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4909 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4910 } 4911 4912 // GAP Bonding API 4913 4914 void sm_bonding_decline(hci_con_handle_t con_handle){ 4915 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4916 if (!sm_conn) return; // wrong connection 4917 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4918 log_info("decline, state %u", sm_conn->sm_engine_state); 4919 switch(sm_conn->sm_engine_state){ 4920 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4921 case SM_SC_W4_USER_RESPONSE: 4922 case SM_SC_W4_CONFIRMATION: 4923 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4924 #endif 4925 case SM_PH1_W4_USER_RESPONSE: 4926 switch (setup->sm_stk_generation_method){ 4927 case PK_RESP_INPUT: 4928 case PK_INIT_INPUT: 4929 case PK_BOTH_INPUT: 4930 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4931 break; 4932 case NUMERIC_COMPARISON: 4933 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4934 break; 4935 case JUST_WORKS: 4936 case OOB: 4937 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4938 break; 4939 default: 4940 btstack_assert(false); 4941 break; 4942 } 4943 break; 4944 default: 4945 break; 4946 } 4947 sm_trigger_run(); 4948 } 4949 4950 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4951 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4952 if (!sm_conn) return; // wrong connection 4953 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4954 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4955 if (setup->sm_use_secure_connections){ 4956 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4957 } else { 4958 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); 4959 } 4960 } 4961 4962 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4963 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4964 sm_sc_prepare_dhkey_check(sm_conn); 4965 } 4966 #endif 4967 4968 sm_trigger_run(); 4969 } 4970 4971 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4972 // for now, it's the same 4973 sm_just_works_confirm(con_handle); 4974 } 4975 4976 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4977 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4978 if (!sm_conn) return; // wrong connection 4979 sm_reset_tk(); 4980 big_endian_store_32(setup->sm_tk, 12, passkey); 4981 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4982 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4983 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); 4984 } 4985 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4986 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4987 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4988 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4989 sm_sc_start_calculating_local_confirm(sm_conn); 4990 } 4991 #endif 4992 sm_trigger_run(); 4993 } 4994 4995 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4996 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4997 if (!sm_conn) return; // wrong connection 4998 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4999 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5000 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5001 switch (action){ 5002 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5003 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5004 flags |= (1u << action); 5005 break; 5006 case SM_KEYPRESS_PASSKEY_CLEARED: 5007 // clear counter, keypress & erased flags + set passkey cleared 5008 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5009 break; 5010 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5011 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 5012 // erase actions queued 5013 num_actions--; 5014 if (num_actions == 0u){ 5015 // clear counter, keypress & erased flags 5016 flags &= 0x19u; 5017 } 5018 break; 5019 } 5020 num_actions++; 5021 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5022 break; 5023 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5024 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5025 // enter actions queued 5026 num_actions--; 5027 if (num_actions == 0u){ 5028 // clear counter, keypress & erased flags 5029 flags &= 0x19u; 5030 } 5031 break; 5032 } 5033 num_actions++; 5034 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5035 break; 5036 default: 5037 break; 5038 } 5039 setup->sm_keypress_notification = (num_actions << 5) | flags; 5040 sm_trigger_run(); 5041 } 5042 5043 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5044 static void sm_handle_random_result_oob(void * arg){ 5045 UNUSED(arg); 5046 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5047 sm_trigger_run(); 5048 } 5049 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5050 5051 static btstack_crypto_random_t sm_crypto_random_oob_request; 5052 5053 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5054 sm_sc_oob_callback = callback; 5055 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5056 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5057 return 0; 5058 } 5059 #endif 5060 5061 /** 5062 * @brief Get Identity Resolving state 5063 * @param con_handle 5064 * @return irk_lookup_state_t 5065 */ 5066 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5067 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5068 if (!sm_conn) return IRK_LOOKUP_IDLE; 5069 return sm_conn->sm_irk_lookup_state; 5070 } 5071 5072 /** 5073 * @brief Identify device in LE Device DB 5074 * @param handle 5075 * @return index from le_device_db or -1 if not found/identified 5076 */ 5077 int sm_le_device_index(hci_con_handle_t con_handle ){ 5078 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5079 if (!sm_conn) return -1; 5080 return sm_conn->sm_le_db_index; 5081 } 5082 5083 static int gap_random_address_type_requires_updates(void){ 5084 switch (gap_random_adress_type){ 5085 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5086 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5087 return 0; 5088 default: 5089 return 1; 5090 } 5091 } 5092 5093 static uint8_t own_address_type(void){ 5094 switch (gap_random_adress_type){ 5095 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5096 return BD_ADDR_TYPE_LE_PUBLIC; 5097 default: 5098 return BD_ADDR_TYPE_LE_RANDOM; 5099 } 5100 } 5101 5102 // GAP LE API 5103 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5104 gap_random_address_update_stop(); 5105 gap_random_adress_type = random_address_type; 5106 hci_le_set_own_address_type(own_address_type()); 5107 if (!gap_random_address_type_requires_updates()) return; 5108 gap_random_address_update_start(); 5109 gap_random_address_trigger(); 5110 } 5111 5112 gap_random_address_type_t gap_random_address_get_mode(void){ 5113 return gap_random_adress_type; 5114 } 5115 5116 void gap_random_address_set_update_period(int period_ms){ 5117 gap_random_adress_update_period = period_ms; 5118 if (!gap_random_address_type_requires_updates()) return; 5119 gap_random_address_update_stop(); 5120 gap_random_address_update_start(); 5121 } 5122 5123 void gap_random_address_set(const bd_addr_t addr){ 5124 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5125 (void)memcpy(sm_random_address, addr, 6); 5126 hci_le_random_address_set(addr); 5127 } 5128 5129 #ifdef ENABLE_LE_PERIPHERAL 5130 /* 5131 * @brief Set Advertisement Paramters 5132 * @param adv_int_min 5133 * @param adv_int_max 5134 * @param adv_type 5135 * @param direct_address_type 5136 * @param direct_address 5137 * @param channel_map 5138 * @param filter_policy 5139 * 5140 * @note own_address_type is used from gap_random_address_set_mode 5141 */ 5142 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5143 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5144 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5145 direct_address_typ, direct_address, channel_map, filter_policy); 5146 } 5147 #endif 5148 5149 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5150 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5151 // wrong connection 5152 if (!sm_conn) return 0; 5153 // already encrypted 5154 if (sm_conn->sm_connection_encrypted) return 0; 5155 // irk status? 5156 switch(sm_conn->sm_irk_lookup_state){ 5157 case IRK_LOOKUP_FAILED: 5158 // done, cannot setup encryption 5159 return 0; 5160 case IRK_LOOKUP_SUCCEEDED: 5161 break; 5162 default: 5163 // IR Lookup pending 5164 return 1; 5165 } 5166 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5167 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5168 if (sm_conn->sm_role){ 5169 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5170 } else { 5171 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5172 } 5173 } 5174 5175 void sm_set_secure_connections_only_mode(bool enable){ 5176 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5177 sm_sc_only_mode = enable; 5178 #else 5179 // SC Only mode not possible without support for SC 5180 btstack_assert(enable == false); 5181 #endif 5182 } 5183 5184 const uint8_t * gap_get_persistent_irk(void){ 5185 return sm_persistent_irk; 5186 } 5187 5188 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5189 uint16_t i; 5190 for (i=0; i < le_device_db_max_count(); i++){ 5191 bd_addr_t entry_address; 5192 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5193 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5194 // skip unused entries 5195 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5196 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5197 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 5198 hci_remove_le_device_db_entry_from_resolving_list(i); 5199 #endif 5200 le_device_db_remove(i); 5201 break; 5202 } 5203 } 5204 } 5205