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 MATTHIAS 24 * RINGWALD 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 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 PK_BOTH_INPUT, // Only input on both, both input PK 128 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on one (SC) or both sides (legacy) 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_DONE, 160 } ec_key_generation_state_t; 161 162 typedef enum { 163 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 164 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 165 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 166 } sm_state_var_t; 167 168 typedef enum { 169 SM_SC_OOB_IDLE, 170 SM_SC_OOB_W4_RANDOM, 171 SM_SC_OOB_W2_CALC_CONFIRM, 172 SM_SC_OOB_W4_CONFIRM, 173 } sm_sc_oob_state_t; 174 175 typedef uint8_t sm_key24_t[3]; 176 typedef uint8_t sm_key56_t[7]; 177 typedef uint8_t sm_key256_t[32]; 178 179 // 180 // GLOBAL DATA 181 // 182 183 static bool test_use_fixed_local_csrk; 184 static bool test_use_fixed_local_irk; 185 186 #ifdef ENABLE_TESTING_SUPPORT 187 static uint8_t test_pairing_failure; 188 #endif 189 190 // configuration 191 static uint8_t sm_accepted_stk_generation_methods; 192 static uint8_t sm_max_encryption_key_size; 193 static uint8_t sm_min_encryption_key_size; 194 static uint8_t sm_auth_req = 0; 195 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 196 static uint8_t sm_slave_request_security; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 201 static bool sm_sc_only_mode; 202 static uint8_t sm_sc_oob_random[16]; 203 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 204 static sm_sc_oob_state_t sm_sc_oob_state; 205 #endif 206 207 208 static uint8_t sm_persistent_keys_random_active; 209 static const btstack_tlv_t * sm_tlv_impl; 210 static void * sm_tlv_context; 211 212 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 213 static sm_key_t sm_persistent_er; 214 static sm_key_t sm_persistent_ir; 215 216 // derived from sm_persistent_ir 217 static sm_key_t sm_persistent_dhk; 218 static sm_key_t sm_persistent_irk; 219 static derived_key_generation_t dkg_state; 220 221 // derived from sm_persistent_er 222 // .. 223 224 // random address update 225 static random_address_update_t rau_state; 226 static bd_addr_t sm_random_address; 227 228 #ifdef USE_CMAC_ENGINE 229 // CMAC Calculation: General 230 static btstack_crypto_aes128_cmac_t sm_cmac_request; 231 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 232 static uint8_t sm_cmac_active; 233 static uint8_t sm_cmac_hash[16]; 234 #endif 235 236 // CMAC for ATT Signed Writes 237 #ifdef ENABLE_LE_SIGNED_WRITE 238 static uint16_t sm_cmac_signed_write_message_len; 239 static uint8_t sm_cmac_signed_write_header[3]; 240 static const uint8_t * sm_cmac_signed_write_message; 241 static uint8_t sm_cmac_signed_write_sign_counter[4]; 242 #endif 243 244 // CMAC for Secure Connection functions 245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 246 static sm_connection_t * sm_cmac_connection; 247 static uint8_t sm_cmac_sc_buffer[80]; 248 #endif 249 250 // resolvable private address lookup / CSRK calculation 251 static int sm_address_resolution_test; 252 static int sm_address_resolution_ah_calculation_active; 253 static uint8_t sm_address_resolution_addr_type; 254 static bd_addr_t sm_address_resolution_address; 255 static void * sm_address_resolution_context; 256 static address_resolution_mode_t sm_address_resolution_mode; 257 static btstack_linked_list_t sm_address_resolution_general_queue; 258 259 // aes128 crypto engine. 260 static sm_aes128_state_t sm_aes128_state; 261 262 // crypto 263 static btstack_crypto_random_t sm_crypto_random_request; 264 static btstack_crypto_aes128_t sm_crypto_aes128_request; 265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 266 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 267 #endif 268 269 // temp storage for random data 270 static uint8_t sm_random_data[8]; 271 static uint8_t sm_aes128_key[16]; 272 static uint8_t sm_aes128_plaintext[16]; 273 static uint8_t sm_aes128_ciphertext[16]; 274 275 // to receive hci events 276 static btstack_packet_callback_registration_t hci_event_callback_registration; 277 278 /* to dispatch sm event */ 279 static btstack_linked_list_t sm_event_handlers; 280 281 /* to schedule calls to sm_run */ 282 static btstack_timer_source_t sm_run_timer; 283 284 // LE Secure Connections 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 static ec_key_generation_state_t ec_key_generation_state; 287 static uint8_t ec_q[64]; 288 #endif 289 290 // 291 // Volume 3, Part H, Chapter 24 292 // "Security shall be initiated by the Security Manager in the device in the master role. 293 // The device in the slave role shall be the responding device." 294 // -> master := initiator, slave := responder 295 // 296 297 // data needed for security setup 298 typedef struct sm_setup_context { 299 300 btstack_timer_source_t sm_timeout; 301 302 // used in all phases 303 uint8_t sm_pairing_failed_reason; 304 305 // user response, (Phase 1 and/or 2) 306 uint8_t sm_user_response; 307 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 308 309 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 310 uint8_t sm_key_distribution_send_set; 311 uint8_t sm_key_distribution_sent_set; 312 uint8_t sm_key_distribution_received_set; 313 314 // Phase 2 (Pairing over SMP) 315 stk_generation_method_t sm_stk_generation_method; 316 sm_key_t sm_tk; 317 uint8_t sm_have_oob_data; 318 uint8_t sm_use_secure_connections; 319 320 sm_key_t sm_c1_t3_value; // c1 calculation 321 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 322 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 323 sm_key_t sm_local_random; 324 sm_key_t sm_local_confirm; 325 sm_key_t sm_peer_random; 326 sm_key_t sm_peer_confirm; 327 uint8_t sm_m_addr_type; // address and type can be removed 328 uint8_t sm_s_addr_type; // '' 329 bd_addr_t sm_m_address; // '' 330 bd_addr_t sm_s_address; // '' 331 sm_key_t sm_ltk; 332 333 uint8_t sm_state_vars; 334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 335 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 336 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 337 sm_key_t sm_local_nonce; // might be combined with sm_local_random 338 uint8_t sm_dhkey[32]; 339 sm_key_t sm_peer_dhkey_check; 340 sm_key_t sm_local_dhkey_check; 341 sm_key_t sm_ra; 342 sm_key_t sm_rb; 343 sm_key_t sm_t; // used for f5 and h6 344 sm_key_t sm_mackey; 345 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 346 #endif 347 348 // Phase 3 349 350 // key distribution, we generate 351 uint16_t sm_local_y; 352 uint16_t sm_local_div; 353 uint16_t sm_local_ediv; 354 uint8_t sm_local_rand[8]; 355 sm_key_t sm_local_ltk; 356 sm_key_t sm_local_csrk; 357 sm_key_t sm_local_irk; 358 // sm_local_address/addr_type not needed 359 360 // key distribution, received from peer 361 uint16_t sm_peer_y; 362 uint16_t sm_peer_div; 363 uint16_t sm_peer_ediv; 364 uint8_t sm_peer_rand[8]; 365 sm_key_t sm_peer_ltk; 366 sm_key_t sm_peer_irk; 367 sm_key_t sm_peer_csrk; 368 uint8_t sm_peer_addr_type; 369 bd_addr_t sm_peer_address; 370 #ifdef ENABLE_LE_SIGNED_WRITE 371 int sm_le_device_index; 372 #endif 373 374 bool sm_reencryption_active; 375 } sm_setup_context_t; 376 377 // 378 static sm_setup_context_t the_setup; 379 static sm_setup_context_t * setup = &the_setup; 380 381 // active connection - the one for which the_setup is used for 382 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 383 384 // @returns 1 if oob data is available 385 // stores oob data in provided 16 byte buffer if not null 386 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 387 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); 388 389 static void sm_run(void); 390 static void sm_done_for_handle(hci_con_handle_t con_handle); 391 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 392 static inline int sm_calc_actual_encryption_key_size(int other); 393 static int sm_validate_stk_generation_method(void); 394 static void sm_handle_encryption_result_address_resolution(void *arg); 395 static void sm_handle_encryption_result_dkg_dhk(void *arg); 396 static void sm_handle_encryption_result_dkg_irk(void *arg); 397 static void sm_handle_encryption_result_enc_a(void *arg); 398 static void sm_handle_encryption_result_enc_b(void *arg); 399 static void sm_handle_encryption_result_enc_c(void *arg); 400 static void sm_handle_encryption_result_enc_csrk(void *arg); 401 static void sm_handle_encryption_result_enc_d(void * arg); 402 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 403 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 404 #ifdef ENABLE_LE_PERIPHERAL 405 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 406 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 407 #endif 408 static void sm_handle_encryption_result_enc_stk(void *arg); 409 static void sm_handle_encryption_result_rau(void *arg); 410 static void sm_handle_random_result_ph2_tk(void * arg); 411 static void sm_handle_random_result_rau(void * arg); 412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 413 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)); 414 static void sm_ec_generate_new_key(void); 415 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 416 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 417 static int sm_passkey_entry(stk_generation_method_t method); 418 #endif 419 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 420 421 static void log_info_hex16(const char * name, uint16_t value){ 422 log_info("%-6s 0x%04x", name, value); 423 } 424 425 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 426 // return packet[0]; 427 // } 428 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 429 return packet[1]; 430 } 431 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 432 return packet[2]; 433 } 434 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 435 return packet[3]; 436 } 437 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 438 return packet[4]; 439 } 440 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 441 return packet[5]; 442 } 443 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 444 return packet[6]; 445 } 446 447 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 448 packet[0] = code; 449 } 450 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 451 packet[1] = io_capability; 452 } 453 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 454 packet[2] = oob_data_flag; 455 } 456 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 457 packet[3] = auth_req; 458 } 459 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 460 packet[4] = max_encryption_key_size; 461 } 462 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 463 packet[5] = initiator_key_distribution; 464 } 465 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 466 packet[6] = responder_key_distribution; 467 } 468 469 // @returns 1 if all bytes are 0 470 static int sm_is_null(uint8_t * data, int size){ 471 int i; 472 for (i=0; i < size ; i++){ 473 if (data[i] != 0) { 474 return 0; 475 } 476 } 477 return 1; 478 } 479 480 static int sm_is_null_random(uint8_t random[8]){ 481 return sm_is_null(random, 8); 482 } 483 484 static int sm_is_null_key(uint8_t * key){ 485 return sm_is_null(key, 16); 486 } 487 488 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 489 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 490 UNUSED(ts); 491 sm_run(); 492 } 493 static void sm_trigger_run(void){ 494 (void)btstack_run_loop_remove_timer(&sm_run_timer); 495 btstack_run_loop_set_timer(&sm_run_timer, 0); 496 btstack_run_loop_add_timer(&sm_run_timer); 497 } 498 499 // Key utils 500 static void sm_reset_tk(void){ 501 int i; 502 for (i=0;i<16;i++){ 503 setup->sm_tk[i] = 0; 504 } 505 } 506 507 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 508 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 509 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 510 int i; 511 for (i = max_encryption_size ; i < 16 ; i++){ 512 key[15-i] = 0; 513 } 514 } 515 516 // ER / IR checks 517 static void sm_er_ir_set_default(void){ 518 int i; 519 for (i=0;i<16;i++){ 520 sm_persistent_er[i] = 0x30 + i; 521 sm_persistent_ir[i] = 0x90 + i; 522 } 523 } 524 525 static int sm_er_is_default(void){ 526 int i; 527 for (i=0;i<16;i++){ 528 if (sm_persistent_er[i] != (0x30+i)) return 0; 529 } 530 return 1; 531 } 532 533 static int sm_ir_is_default(void){ 534 int i; 535 for (i=0;i<16;i++){ 536 if (sm_persistent_ir[i] != (0x90+i)) return 0; 537 } 538 return 1; 539 } 540 541 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 542 UNUSED(channel); 543 544 // log event 545 hci_dump_packet(packet_type, 1, packet, size); 546 // dispatch to all event handlers 547 btstack_linked_list_iterator_t it; 548 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 549 while (btstack_linked_list_iterator_has_next(&it)){ 550 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 551 entry->callback(packet_type, 0, packet, size); 552 } 553 } 554 555 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){ 556 event[0] = type; 557 event[1] = event_size - 2; 558 little_endian_store_16(event, 2, con_handle); 559 event[4] = addr_type; 560 reverse_bd_addr(address, &event[5]); 561 } 562 563 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 564 uint8_t event[11]; 565 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 566 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 567 } 568 569 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){ 570 uint8_t event[15]; 571 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 572 little_endian_store_32(event, 11, passkey); 573 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 574 } 575 576 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){ 577 // fetch addr and addr type from db, only called for valid entries 578 bd_addr_t identity_address; 579 int identity_address_type; 580 le_device_db_info(index, &identity_address_type, identity_address, NULL); 581 582 uint8_t event[20]; 583 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 584 event[11] = identity_address_type; 585 reverse_bd_addr(identity_address, &event[12]); 586 little_endian_store_16(event, 18, index); 587 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 588 } 589 590 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){ 591 uint8_t event[12]; 592 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 593 event[11] = status; 594 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 595 } 596 597 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 598 uint8_t event[13]; 599 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 600 event[11] = status; 601 event[12] = reason; 602 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 603 } 604 605 static void sm_reencryption_started(sm_connection_t * sm_conn){ 606 607 setup->sm_reencryption_active = true; 608 609 // fetch addr and addr type from db, only called for valid entries 610 int identity_addr_type; 611 bd_addr_t identity_addr; 612 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 613 614 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 615 } 616 617 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 618 619 setup->sm_reencryption_active = false; 620 621 // fetch addr and addr type from db, only called for valid entries 622 int identity_addr_type; 623 bd_addr_t identity_addr; 624 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 625 626 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 627 } 628 629 // SMP Timeout implementation 630 631 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 632 // the Security Manager Timer shall be reset and started. 633 // 634 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 635 // 636 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 637 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 638 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 639 // established. 640 641 static void sm_timeout_handler(btstack_timer_source_t * timer){ 642 log_info("SM timeout"); 643 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 644 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 645 646 if (setup->sm_reencryption_active){ 647 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 648 } 649 650 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 651 sm_done_for_handle(sm_conn->sm_handle); 652 653 // trigger handling of next ready connection 654 sm_run(); 655 } 656 static void sm_timeout_start(sm_connection_t * sm_conn){ 657 btstack_run_loop_remove_timer(&setup->sm_timeout); 658 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 659 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 660 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 661 btstack_run_loop_add_timer(&setup->sm_timeout); 662 } 663 static void sm_timeout_stop(void){ 664 btstack_run_loop_remove_timer(&setup->sm_timeout); 665 } 666 static void sm_timeout_reset(sm_connection_t * sm_conn){ 667 sm_timeout_stop(); 668 sm_timeout_start(sm_conn); 669 } 670 671 // end of sm timeout 672 673 // GAP Random Address updates 674 static gap_random_address_type_t gap_random_adress_type; 675 static btstack_timer_source_t gap_random_address_update_timer; 676 static uint32_t gap_random_adress_update_period; 677 678 static void gap_random_address_trigger(void){ 679 log_info("gap_random_address_trigger, state %u", rau_state); 680 if (rau_state != RAU_IDLE) return; 681 rau_state = RAU_GET_RANDOM; 682 sm_trigger_run(); 683 } 684 685 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 686 UNUSED(timer); 687 688 log_info("GAP Random Address Update due"); 689 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 690 btstack_run_loop_add_timer(&gap_random_address_update_timer); 691 gap_random_address_trigger(); 692 } 693 694 static void gap_random_address_update_start(void){ 695 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 696 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 697 btstack_run_loop_add_timer(&gap_random_address_update_timer); 698 } 699 700 static void gap_random_address_update_stop(void){ 701 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 702 } 703 704 // ah(k,r) helper 705 // r = padding || r 706 // r - 24 bit value 707 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 708 // r'= padding || r 709 memset(r_prime, 0, 16); 710 (void)memcpy(&r_prime[13], r, 3); 711 } 712 713 // d1 helper 714 // d' = padding || r || d 715 // d,r - 16 bit values 716 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 717 // d'= padding || r || d 718 memset(d1_prime, 0, 16); 719 big_endian_store_16(d1_prime, 12, r); 720 big_endian_store_16(d1_prime, 14, d); 721 } 722 723 // calculate arguments for first AES128 operation in C1 function 724 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){ 725 726 // p1 = pres || preq || rat’ || iat’ 727 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 728 // cant octet of pres becomes the most significant octet of p1. 729 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 730 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 731 // p1 is 0x05000800000302070710000001010001." 732 733 sm_key_t p1; 734 reverse_56(pres, &p1[0]); 735 reverse_56(preq, &p1[7]); 736 p1[14] = rat; 737 p1[15] = iat; 738 log_info_key("p1", p1); 739 log_info_key("r", r); 740 741 // t1 = r xor p1 742 int i; 743 for (i=0;i<16;i++){ 744 t1[i] = r[i] ^ p1[i]; 745 } 746 log_info_key("t1", t1); 747 } 748 749 // calculate arguments for second AES128 operation in C1 function 750 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 751 // p2 = padding || ia || ra 752 // "The least significant octet of ra becomes the least significant octet of p2 and 753 // the most significant octet of padding becomes the most significant octet of p2. 754 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 755 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 756 757 sm_key_t p2; 758 memset(p2, 0, 16); 759 (void)memcpy(&p2[4], ia, 6); 760 (void)memcpy(&p2[10], ra, 6); 761 log_info_key("p2", p2); 762 763 // c1 = e(k, t2_xor_p2) 764 int i; 765 for (i=0;i<16;i++){ 766 t3[i] = t2[i] ^ p2[i]; 767 } 768 log_info_key("t3", t3); 769 } 770 771 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 772 log_info_key("r1", r1); 773 log_info_key("r2", r2); 774 (void)memcpy(&r_prime[8], &r2[8], 8); 775 (void)memcpy(&r_prime[0], &r1[8], 8); 776 } 777 778 779 // decide on stk generation based on 780 // - pairing request 781 // - io capabilities 782 // - OOB data availability 783 static void sm_setup_tk(void){ 784 785 // horizontal: initiator capabilities 786 // vertial: responder capabilities 787 static const stk_generation_method_t stk_generation_method [5] [5] = { 788 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 789 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 790 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 791 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 792 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 793 }; 794 795 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 796 #ifdef ENABLE_LE_SECURE_CONNECTIONS 797 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 798 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 799 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 800 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 801 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 802 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 803 }; 804 #endif 805 806 // default: just works 807 setup->sm_stk_generation_method = JUST_WORKS; 808 809 #ifdef ENABLE_LE_SECURE_CONNECTIONS 810 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 811 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 812 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 813 #else 814 setup->sm_use_secure_connections = 0; 815 #endif 816 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 817 818 819 // decide if OOB will be used based on SC vs. Legacy and oob flags 820 int use_oob = 0; 821 if (setup->sm_use_secure_connections){ 822 // In LE Secure Connections pairing, the out of band method is used if at least 823 // one device has the peer device's out of band authentication data available. 824 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 825 } else { 826 // In LE legacy pairing, the out of band method is used if both the devices have 827 // the other device's out of band authentication data available. 828 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 829 } 830 if (use_oob){ 831 log_info("SM: have OOB data"); 832 log_info_key("OOB", setup->sm_tk); 833 setup->sm_stk_generation_method = OOB; 834 return; 835 } 836 837 // If both devices have not set the MITM option in the Authentication Requirements 838 // Flags, then the IO capabilities shall be ignored and the Just Works association 839 // model shall be used. 840 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 841 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 842 log_info("SM: MITM not required by both -> JUST WORKS"); 843 return; 844 } 845 846 // Reset TK as it has been setup in sm_init_setup 847 sm_reset_tk(); 848 849 // Also use just works if unknown io capabilites 850 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)){ 851 return; 852 } 853 854 // Otherwise the IO capabilities of the devices shall be used to determine the 855 // pairing method as defined in Table 2.4. 856 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 857 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 858 859 #ifdef ENABLE_LE_SECURE_CONNECTIONS 860 // table not define by default 861 if (setup->sm_use_secure_connections){ 862 generation_method = stk_generation_method_with_secure_connection; 863 } 864 #endif 865 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)]; 866 867 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 868 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); 869 } 870 871 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 872 int flags = 0; 873 if (key_set & SM_KEYDIST_ENC_KEY){ 874 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 875 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 876 } 877 if (key_set & SM_KEYDIST_ID_KEY){ 878 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 879 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 880 } 881 if (key_set & SM_KEYDIST_SIGN){ 882 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 883 } 884 return flags; 885 } 886 887 static void sm_setup_key_distribution(uint8_t key_set){ 888 setup->sm_key_distribution_received_set = 0; 889 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 890 setup->sm_key_distribution_sent_set = 0; 891 #ifdef ENABLE_LE_SIGNED_WRITE 892 setup->sm_le_device_index = -1; 893 #endif 894 } 895 896 // CSRK Key Lookup 897 898 899 static int sm_address_resolution_idle(void){ 900 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 901 } 902 903 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){ 904 (void)memcpy(sm_address_resolution_address, addr, 6); 905 sm_address_resolution_addr_type = addr_type; 906 sm_address_resolution_test = 0; 907 sm_address_resolution_mode = mode; 908 sm_address_resolution_context = context; 909 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 910 } 911 912 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 913 // check if already in list 914 btstack_linked_list_iterator_t it; 915 sm_lookup_entry_t * entry; 916 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 917 while(btstack_linked_list_iterator_has_next(&it)){ 918 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 919 if (entry->address_type != address_type) continue; 920 if (memcmp(entry->address, address, 6)) continue; 921 // already in list 922 return BTSTACK_BUSY; 923 } 924 entry = btstack_memory_sm_lookup_entry_get(); 925 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 926 entry->address_type = (bd_addr_type_t) address_type; 927 (void)memcpy(entry->address, address, 6); 928 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 929 sm_trigger_run(); 930 return 0; 931 } 932 933 // CMAC calculation using AES Engineq 934 #ifdef USE_CMAC_ENGINE 935 936 static void sm_cmac_done_trampoline(void * arg){ 937 UNUSED(arg); 938 sm_cmac_active = 0; 939 (*sm_cmac_done_callback)(sm_cmac_hash); 940 sm_trigger_run(); 941 } 942 943 int sm_cmac_ready(void){ 944 return sm_cmac_active == 0u; 945 } 946 #endif 947 948 #ifdef ENABLE_LE_SECURE_CONNECTIONS 949 // generic cmac calculation 950 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)){ 951 sm_cmac_active = 1; 952 sm_cmac_done_callback = done_callback; 953 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 954 } 955 #endif 956 957 // cmac for ATT Message signing 958 #ifdef ENABLE_LE_SIGNED_WRITE 959 960 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)){ 961 sm_cmac_active = 1; 962 sm_cmac_done_callback = done_callback; 963 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 964 } 965 966 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 967 if (offset >= sm_cmac_signed_write_message_len) { 968 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 969 return 0; 970 } 971 972 offset = sm_cmac_signed_write_message_len - 1 - offset; 973 974 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 975 if (offset < 3){ 976 return sm_cmac_signed_write_header[offset]; 977 } 978 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 979 if (offset < actual_message_len_incl_header){ 980 return sm_cmac_signed_write_message[offset - 3]; 981 } 982 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 983 } 984 985 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)){ 986 // ATT Message Signing 987 sm_cmac_signed_write_header[0] = opcode; 988 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 989 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 990 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 991 sm_cmac_signed_write_message = message; 992 sm_cmac_signed_write_message_len = total_message_len; 993 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 994 } 995 #endif 996 997 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 998 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 999 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1000 switch (setup->sm_stk_generation_method){ 1001 case PK_RESP_INPUT: 1002 if (IS_RESPONDER(sm_conn->sm_role)){ 1003 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1004 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1005 } else { 1006 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)); 1007 } 1008 break; 1009 case PK_INIT_INPUT: 1010 if (IS_RESPONDER(sm_conn->sm_role)){ 1011 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)); 1012 } else { 1013 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1014 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1015 } 1016 break; 1017 case PK_BOTH_INPUT: 1018 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1019 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1020 break; 1021 case NUMERIC_COMPARISON: 1022 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1023 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)); 1024 break; 1025 case JUST_WORKS: 1026 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1027 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1028 break; 1029 case OOB: 1030 // client already provided OOB data, let's skip notification. 1031 break; 1032 default: 1033 btstack_assert(false); 1034 break; 1035 } 1036 } 1037 1038 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1039 int recv_flags; 1040 if (IS_RESPONDER(sm_conn->sm_role)){ 1041 // slave / responder 1042 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1043 } else { 1044 // master / initiator 1045 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1046 } 1047 1048 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1049 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1050 if (setup->sm_use_secure_connections){ 1051 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1052 } 1053 #endif 1054 1055 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1056 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1057 } 1058 1059 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1060 if (sm_active_connection_handle == con_handle){ 1061 sm_timeout_stop(); 1062 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1063 log_info("sm: connection 0x%x released setup context", con_handle); 1064 1065 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1066 // generate new ec key after each pairing (that used it) 1067 if (setup->sm_use_secure_connections){ 1068 sm_ec_generate_new_key(); 1069 } 1070 #endif 1071 } 1072 } 1073 1074 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1075 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1076 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1077 sm_done_for_handle(connection->sm_handle); 1078 } 1079 1080 static int sm_key_distribution_flags_for_auth_req(void){ 1081 1082 int flags = SM_KEYDIST_ID_KEY; 1083 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1084 // encryption and signing information only if bonding requested 1085 flags |= SM_KEYDIST_ENC_KEY; 1086 #ifdef ENABLE_LE_SIGNED_WRITE 1087 flags |= SM_KEYDIST_SIGN; 1088 #endif 1089 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1090 // LinkKey for CTKD requires SC 1091 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1092 flags |= SM_KEYDIST_LINK_KEY; 1093 } 1094 #endif 1095 } 1096 return flags; 1097 } 1098 1099 static void sm_reset_setup(void){ 1100 // fill in sm setup 1101 setup->sm_state_vars = 0; 1102 setup->sm_keypress_notification = 0; 1103 sm_reset_tk(); 1104 setup->sm_reencryption_active = false; 1105 } 1106 1107 static void sm_init_setup(sm_connection_t * sm_conn){ 1108 1109 // fill in sm setup 1110 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1111 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1112 1113 // query client for Legacy Pairing OOB data 1114 setup->sm_have_oob_data = 0; 1115 if (sm_get_oob_data) { 1116 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1117 } 1118 1119 // if available and SC supported, also ask for SC OOB Data 1120 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1121 memset(setup->sm_ra, 0, 16); 1122 memset(setup->sm_rb, 0, 16); 1123 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1124 if (sm_get_sc_oob_data){ 1125 if (IS_RESPONDER(sm_conn->sm_role)){ 1126 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1127 sm_conn->sm_peer_addr_type, 1128 sm_conn->sm_peer_address, 1129 setup->sm_peer_confirm, 1130 setup->sm_ra); 1131 } else { 1132 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1133 sm_conn->sm_peer_addr_type, 1134 sm_conn->sm_peer_address, 1135 setup->sm_peer_confirm, 1136 setup->sm_rb); 1137 } 1138 } else { 1139 setup->sm_have_oob_data = 0; 1140 } 1141 } 1142 #endif 1143 1144 sm_pairing_packet_t * local_packet; 1145 if (IS_RESPONDER(sm_conn->sm_role)){ 1146 // slave 1147 local_packet = &setup->sm_s_pres; 1148 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1149 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1150 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1151 } else { 1152 // master 1153 local_packet = &setup->sm_m_preq; 1154 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1155 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1156 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1157 1158 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1159 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1160 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1161 } 1162 1163 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1164 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1165 // set CT2 if SC + Bonding + CTKD 1166 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1167 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1168 auth_req |= SM_AUTHREQ_CT2; 1169 } 1170 #endif 1171 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1172 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1173 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1174 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1175 } 1176 1177 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1178 1179 sm_pairing_packet_t * remote_packet; 1180 int remote_key_request; 1181 if (IS_RESPONDER(sm_conn->sm_role)){ 1182 // slave / responder 1183 remote_packet = &setup->sm_m_preq; 1184 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1185 } else { 1186 // master / initiator 1187 remote_packet = &setup->sm_s_pres; 1188 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1189 } 1190 1191 // check key size 1192 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1193 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1194 1195 // decide on STK generation method / SC 1196 sm_setup_tk(); 1197 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1198 1199 // check if STK generation method is acceptable by client 1200 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1201 1202 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1203 // check LE SC Only mode 1204 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1205 log_info("SC Only mode active but SC not possible"); 1206 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1207 } 1208 1209 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1210 if (setup->sm_use_secure_connections){ 1211 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1212 } 1213 #endif 1214 1215 // identical to responder 1216 sm_setup_key_distribution(remote_key_request); 1217 1218 // JUST WORKS doens't provide authentication 1219 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1220 1221 return 0; 1222 } 1223 1224 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1225 1226 // cache and reset context 1227 int matched_device_id = sm_address_resolution_test; 1228 address_resolution_mode_t mode = sm_address_resolution_mode; 1229 void * context = sm_address_resolution_context; 1230 1231 // reset context 1232 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1233 sm_address_resolution_context = NULL; 1234 sm_address_resolution_test = -1; 1235 hci_con_handle_t con_handle = 0; 1236 1237 sm_connection_t * sm_connection; 1238 sm_key_t ltk; 1239 int have_ltk; 1240 #ifdef ENABLE_LE_CENTRAL 1241 int trigger_pairing; 1242 #endif 1243 switch (mode){ 1244 case ADDRESS_RESOLUTION_GENERAL: 1245 break; 1246 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1247 sm_connection = (sm_connection_t *) context; 1248 con_handle = sm_connection->sm_handle; 1249 1250 // have ltk -> start encryption / send security request 1251 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1252 // "When a bond has been created between two devices, any reconnection should result in the local device 1253 // enabling or requesting encryption with the remote device before initiating any service request." 1254 1255 switch (event){ 1256 case ADDRESS_RESOLUTION_SUCCEEDED: 1257 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1258 sm_connection->sm_le_db_index = matched_device_id; 1259 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1260 1261 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1262 have_ltk = !sm_is_null_key(ltk); 1263 1264 if (sm_connection->sm_role) { 1265 1266 #ifdef ENABLE_LE_PERIPHERAL 1267 1268 // LTK request received before, IRK required -> start LTK calculation 1269 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1270 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1271 break; 1272 } 1273 1274 if (have_ltk) { 1275 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1276 log_info("central: enable encryption for bonded device"); 1277 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1278 sm_reencryption_started(sm_connection); 1279 sm_trigger_run(); 1280 #else 1281 log_info("central: defer security request for bonded device"); 1282 #endif 1283 } 1284 #endif 1285 } else { 1286 1287 #ifdef ENABLE_LE_CENTRAL 1288 1289 // check if pairing already requested and reset requests 1290 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1291 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1292 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, trigger_pairing, have_ltk); 1293 sm_connection->sm_security_request_received = 0; 1294 sm_connection->sm_pairing_requested = 0; 1295 bool trigger_reencryption = false; 1296 1297 if (have_ltk){ 1298 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1299 trgigger_reencryptipm = true; 1300 #else 1301 if (trigger_pairing){ 1302 trigger_reencryption = true; 1303 } else { 1304 log_info("central: defer enabling encryption for bonded device"); 1305 } 1306 #endif 1307 } 1308 1309 if (trigger_reencryption){ 1310 log_info("central: enable encryption for bonded device"); 1311 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1312 sm_reencryption_started(sm_connection); 1313 break; 1314 } 1315 1316 // pairing_request -> send pairing request 1317 if (trigger_pairing){ 1318 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1319 break; 1320 } 1321 } 1322 #endif 1323 break; 1324 case ADDRESS_RESOLUTION_FAILED: 1325 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1326 if (sm_connection->sm_role) { 1327 // LTK request received before, IRK required -> negative LTK reply 1328 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1329 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1330 } 1331 break; 1332 } 1333 #ifdef ENABLE_LE_CENTRAL 1334 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1335 sm_connection->sm_security_request_received = 0; 1336 sm_connection->sm_pairing_requested = 0; 1337 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1338 #endif 1339 break; 1340 1341 default: 1342 btstack_assert(false); 1343 break; 1344 } 1345 break; 1346 default: 1347 break; 1348 } 1349 1350 switch (event){ 1351 case ADDRESS_RESOLUTION_SUCCEEDED: 1352 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1353 break; 1354 case ADDRESS_RESOLUTION_FAILED: 1355 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1356 break; 1357 default: 1358 btstack_assert(false); 1359 break; 1360 } 1361 } 1362 1363 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1364 1365 int le_db_index = -1; 1366 1367 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1368 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1369 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1370 & SM_AUTHREQ_BONDING ) != 0u; 1371 1372 if (bonding_enabed){ 1373 1374 // lookup device based on IRK 1375 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1376 int i; 1377 for (i=0; i < le_device_db_max_count(); i++){ 1378 sm_key_t irk; 1379 bd_addr_t address; 1380 int address_type = BD_ADDR_TYPE_UNKNOWN; 1381 le_device_db_info(i, &address_type, address, irk); 1382 // skip unused entries 1383 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1384 // compare IRK 1385 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1386 1387 log_info("sm: device found for IRK, updating"); 1388 le_db_index = i; 1389 break; 1390 } 1391 } else { 1392 // assert IRK is set to zero 1393 memset(setup->sm_peer_irk, 0, 16); 1394 } 1395 1396 // if not found, lookup via public address if possible 1397 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1398 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1399 int i; 1400 for (i=0; i < le_device_db_max_count(); i++){ 1401 bd_addr_t address; 1402 int address_type = BD_ADDR_TYPE_UNKNOWN; 1403 le_device_db_info(i, &address_type, address, NULL); 1404 // skip unused entries 1405 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1406 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1407 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1408 log_info("sm: device found for public address, updating"); 1409 le_db_index = i; 1410 break; 1411 } 1412 } 1413 } 1414 1415 // if not found, add to db 1416 bool new_to_le_device_db = false; 1417 if (le_db_index < 0) { 1418 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1419 new_to_le_device_db = true; 1420 } 1421 1422 if (le_db_index >= 0){ 1423 1424 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1425 if (!new_to_le_device_db){ 1426 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1427 } 1428 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1429 #else 1430 UNUSED(new_to_le_device_db); 1431 #endif 1432 1433 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1434 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1435 1436 #ifdef ENABLE_LE_SIGNED_WRITE 1437 // store local CSRK 1438 setup->sm_le_device_index = le_db_index; 1439 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1440 log_info("sm: store local CSRK"); 1441 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1442 le_device_db_local_counter_set(le_db_index, 0); 1443 } 1444 1445 // store remote CSRK 1446 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1447 log_info("sm: store remote CSRK"); 1448 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1449 le_device_db_remote_counter_set(le_db_index, 0); 1450 } 1451 #endif 1452 // store encryption information for secure connections: LTK generated by ECDH 1453 if (setup->sm_use_secure_connections){ 1454 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1455 uint8_t zero_rand[8]; 1456 memset(zero_rand, 0, 8); 1457 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1458 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1459 } 1460 1461 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1462 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1463 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1464 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1465 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1466 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1467 1468 } 1469 } 1470 } else { 1471 log_info("Ignoring received keys, bonding not enabled"); 1472 } 1473 1474 // keep le_db_index 1475 sm_conn->sm_le_db_index = le_db_index; 1476 } 1477 1478 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1479 setup->sm_pairing_failed_reason = reason; 1480 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1481 } 1482 1483 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1484 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1485 } 1486 1487 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1488 1489 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1490 static int sm_passkey_used(stk_generation_method_t method); 1491 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1492 1493 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1494 if (setup->sm_stk_generation_method == OOB){ 1495 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1496 } else { 1497 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); 1498 } 1499 } 1500 1501 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1502 if (IS_RESPONDER(sm_conn->sm_role)){ 1503 // Responder 1504 if (setup->sm_stk_generation_method == OOB){ 1505 // generate Nb 1506 log_info("Generate Nb"); 1507 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); 1508 } else { 1509 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1510 } 1511 } else { 1512 // Initiator role 1513 switch (setup->sm_stk_generation_method){ 1514 case JUST_WORKS: 1515 sm_sc_prepare_dhkey_check(sm_conn); 1516 break; 1517 1518 case NUMERIC_COMPARISON: 1519 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1520 break; 1521 case PK_INIT_INPUT: 1522 case PK_RESP_INPUT: 1523 case PK_BOTH_INPUT: 1524 if (setup->sm_passkey_bit < 20u) { 1525 sm_sc_start_calculating_local_confirm(sm_conn); 1526 } else { 1527 sm_sc_prepare_dhkey_check(sm_conn); 1528 } 1529 break; 1530 case OOB: 1531 sm_sc_prepare_dhkey_check(sm_conn); 1532 break; 1533 default: 1534 btstack_assert(false); 1535 break; 1536 } 1537 } 1538 } 1539 1540 static void sm_sc_cmac_done(uint8_t * hash){ 1541 log_info("sm_sc_cmac_done: "); 1542 log_info_hexdump(hash, 16); 1543 1544 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1545 sm_sc_oob_state = SM_SC_OOB_IDLE; 1546 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1547 return; 1548 } 1549 1550 sm_connection_t * sm_conn = sm_cmac_connection; 1551 sm_cmac_connection = NULL; 1552 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1553 link_key_type_t link_key_type; 1554 #endif 1555 1556 switch (sm_conn->sm_engine_state){ 1557 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1558 (void)memcpy(setup->sm_local_confirm, hash, 16); 1559 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1560 break; 1561 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1562 // check 1563 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1564 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1565 break; 1566 } 1567 sm_sc_state_after_receiving_random(sm_conn); 1568 break; 1569 case SM_SC_W4_CALCULATE_G2: { 1570 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1571 big_endian_store_32(setup->sm_tk, 12, vab); 1572 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1573 sm_trigger_user_response(sm_conn); 1574 break; 1575 } 1576 case SM_SC_W4_CALCULATE_F5_SALT: 1577 (void)memcpy(setup->sm_t, hash, 16); 1578 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1579 break; 1580 case SM_SC_W4_CALCULATE_F5_MACKEY: 1581 (void)memcpy(setup->sm_mackey, hash, 16); 1582 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1583 break; 1584 case SM_SC_W4_CALCULATE_F5_LTK: 1585 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1586 // Errata Service Release to the Bluetooth Specification: ESR09 1587 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1588 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1589 (void)memcpy(setup->sm_ltk, hash, 16); 1590 (void)memcpy(setup->sm_local_ltk, hash, 16); 1591 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1592 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1593 break; 1594 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1595 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1596 if (IS_RESPONDER(sm_conn->sm_role)){ 1597 // responder 1598 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1599 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1600 } else { 1601 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1602 } 1603 } else { 1604 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1605 } 1606 break; 1607 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1608 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1609 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1610 break; 1611 } 1612 if (IS_RESPONDER(sm_conn->sm_role)){ 1613 // responder 1614 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1615 } else { 1616 // initiator 1617 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1618 } 1619 break; 1620 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1621 case SM_SC_W4_CALCULATE_ILK: 1622 (void)memcpy(setup->sm_t, hash, 16); 1623 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1624 break; 1625 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1626 reverse_128(hash, setup->sm_t); 1627 link_key_type = sm_conn->sm_connection_authenticated ? 1628 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1629 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1630 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1631 if (IS_RESPONDER(sm_conn->sm_role)){ 1632 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1633 } else { 1634 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1635 } 1636 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1637 sm_done_for_handle(sm_conn->sm_handle); 1638 break; 1639 #endif 1640 default: 1641 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1642 break; 1643 } 1644 sm_trigger_run(); 1645 } 1646 1647 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){ 1648 const uint16_t message_len = 65; 1649 sm_cmac_connection = sm_conn; 1650 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1651 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1652 sm_cmac_sc_buffer[64] = z; 1653 log_info("f4 key"); 1654 log_info_hexdump(x, 16); 1655 log_info("f4 message"); 1656 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1657 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1658 } 1659 1660 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1661 static const uint8_t f5_length[] = { 0x01, 0x00}; 1662 1663 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1664 1665 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1666 1667 log_info("f5_calculate_salt"); 1668 // calculate salt for f5 1669 const uint16_t message_len = 32; 1670 sm_cmac_connection = sm_conn; 1671 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1672 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1673 } 1674 1675 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){ 1676 const uint16_t message_len = 53; 1677 sm_cmac_connection = sm_conn; 1678 1679 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1680 sm_cmac_sc_buffer[0] = 0; 1681 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1682 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1683 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1684 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1685 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1686 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1687 log_info("f5 key"); 1688 log_info_hexdump(t, 16); 1689 log_info("f5 message for MacKey"); 1690 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1691 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1692 } 1693 1694 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1695 sm_key56_t bd_addr_master, bd_addr_slave; 1696 bd_addr_master[0] = setup->sm_m_addr_type; 1697 bd_addr_slave[0] = setup->sm_s_addr_type; 1698 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1699 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1700 if (IS_RESPONDER(sm_conn->sm_role)){ 1701 // responder 1702 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1703 } else { 1704 // initiator 1705 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1706 } 1707 } 1708 1709 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1710 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1711 const uint16_t message_len = 53; 1712 sm_cmac_connection = sm_conn; 1713 sm_cmac_sc_buffer[0] = 1; 1714 // 1..52 setup before 1715 log_info("f5 key"); 1716 log_info_hexdump(t, 16); 1717 log_info("f5 message for LTK"); 1718 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1719 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1720 } 1721 1722 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1723 f5_ltk(sm_conn, setup->sm_t); 1724 } 1725 1726 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){ 1727 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1728 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1729 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1730 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1731 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1732 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1733 } 1734 1735 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1736 const uint16_t message_len = 65; 1737 sm_cmac_connection = sm_conn; 1738 log_info("f6 key"); 1739 log_info_hexdump(w, 16); 1740 log_info("f6 message"); 1741 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1742 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1743 } 1744 1745 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1746 // - U is 256 bits 1747 // - V is 256 bits 1748 // - X is 128 bits 1749 // - Y is 128 bits 1750 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){ 1751 const uint16_t message_len = 80; 1752 sm_cmac_connection = sm_conn; 1753 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1754 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1755 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1756 log_info("g2 key"); 1757 log_info_hexdump(x, 16); 1758 log_info("g2 message"); 1759 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1760 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1761 } 1762 1763 static void g2_calculate(sm_connection_t * sm_conn) { 1764 // calc Va if numeric comparison 1765 if (IS_RESPONDER(sm_conn->sm_role)){ 1766 // responder 1767 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1768 } else { 1769 // initiator 1770 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1771 } 1772 } 1773 1774 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1775 uint8_t z = 0; 1776 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1777 // some form of passkey 1778 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1779 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1780 setup->sm_passkey_bit++; 1781 } 1782 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1783 } 1784 1785 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1786 // OOB 1787 if (setup->sm_stk_generation_method == OOB){ 1788 if (IS_RESPONDER(sm_conn->sm_role)){ 1789 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1790 } else { 1791 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1792 } 1793 return; 1794 } 1795 1796 uint8_t z = 0; 1797 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1798 // some form of passkey 1799 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1800 // sm_passkey_bit was increased before sending confirm value 1801 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1802 } 1803 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1804 } 1805 1806 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1807 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1808 1809 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1810 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1811 return; 1812 } else { 1813 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1814 } 1815 } 1816 1817 static void sm_sc_dhkey_calculated(void * arg){ 1818 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1819 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1820 if (sm_conn == NULL) return; 1821 1822 log_info("dhkey"); 1823 log_info_hexdump(&setup->sm_dhkey[0], 32); 1824 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1825 // trigger next step 1826 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1827 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1828 } 1829 sm_trigger_run(); 1830 } 1831 1832 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1833 // calculate DHKCheck 1834 sm_key56_t bd_addr_master, bd_addr_slave; 1835 bd_addr_master[0] = setup->sm_m_addr_type; 1836 bd_addr_slave[0] = setup->sm_s_addr_type; 1837 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1838 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1839 uint8_t iocap_a[3]; 1840 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1841 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1842 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1843 uint8_t iocap_b[3]; 1844 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1845 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1846 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1847 if (IS_RESPONDER(sm_conn->sm_role)){ 1848 // responder 1849 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1850 f6_engine(sm_conn, setup->sm_mackey); 1851 } else { 1852 // initiator 1853 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1854 f6_engine(sm_conn, setup->sm_mackey); 1855 } 1856 } 1857 1858 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1859 // validate E = f6() 1860 sm_key56_t bd_addr_master, bd_addr_slave; 1861 bd_addr_master[0] = setup->sm_m_addr_type; 1862 bd_addr_slave[0] = setup->sm_s_addr_type; 1863 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1864 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1865 1866 uint8_t iocap_a[3]; 1867 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1868 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1869 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1870 uint8_t iocap_b[3]; 1871 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1872 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1873 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1874 if (IS_RESPONDER(sm_conn->sm_role)){ 1875 // responder 1876 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1877 f6_engine(sm_conn, setup->sm_mackey); 1878 } else { 1879 // initiator 1880 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1881 f6_engine(sm_conn, setup->sm_mackey); 1882 } 1883 } 1884 1885 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1886 1887 // 1888 // Link Key Conversion Function h6 1889 // 1890 // h6(W, keyID) = AES-CMAC_W(keyID) 1891 // - W is 128 bits 1892 // - keyID is 32 bits 1893 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1894 const uint16_t message_len = 4; 1895 sm_cmac_connection = sm_conn; 1896 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1897 log_info("h6 key"); 1898 log_info_hexdump(w, 16); 1899 log_info("h6 message"); 1900 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1901 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1902 } 1903 // 1904 // Link Key Conversion Function h7 1905 // 1906 // h7(SALT, W) = AES-CMAC_SALT(W) 1907 // - SALT is 128 bits 1908 // - W is 128 bits 1909 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1910 const uint16_t message_len = 16; 1911 sm_cmac_connection = sm_conn; 1912 log_info("h7 key"); 1913 log_info_hexdump(salt, 16); 1914 log_info("h7 message"); 1915 log_info_hexdump(w, 16); 1916 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1917 } 1918 1919 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1920 // Errata Service Release to the Bluetooth Specification: ESR09 1921 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1922 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1923 1924 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1925 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1926 } 1927 1928 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1929 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1930 } 1931 1932 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1933 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1934 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1935 } 1936 #endif 1937 1938 #endif 1939 1940 // key management legacy connections: 1941 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1942 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1943 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1944 // - responder reconnects: responder uses LTK receveived from master 1945 1946 // key management secure connections: 1947 // - both devices store same LTK from ECDH key exchange. 1948 1949 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1950 static void sm_load_security_info(sm_connection_t * sm_connection){ 1951 int encryption_key_size; 1952 int authenticated; 1953 int authorized; 1954 int secure_connection; 1955 1956 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1957 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1958 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1959 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); 1960 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1961 sm_connection->sm_connection_authenticated = authenticated; 1962 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1963 sm_connection->sm_connection_sc = secure_connection; 1964 } 1965 #endif 1966 1967 #ifdef ENABLE_LE_PERIPHERAL 1968 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1969 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1970 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1971 // re-establish used key encryption size 1972 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1973 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1974 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1975 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1976 // Legacy paring -> not SC 1977 sm_connection->sm_connection_sc = 0; 1978 log_info("sm: received ltk request with key size %u, authenticated %u", 1979 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1980 } 1981 #endif 1982 1983 // distributed key generation 1984 static bool sm_run_dpkg(void){ 1985 switch (dkg_state){ 1986 case DKG_CALC_IRK: 1987 // already busy? 1988 if (sm_aes128_state == SM_AES128_IDLE) { 1989 log_info("DKG_CALC_IRK started"); 1990 // IRK = d1(IR, 1, 0) 1991 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1992 sm_aes128_state = SM_AES128_ACTIVE; 1993 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1994 return true; 1995 } 1996 break; 1997 case DKG_CALC_DHK: 1998 // already busy? 1999 if (sm_aes128_state == SM_AES128_IDLE) { 2000 log_info("DKG_CALC_DHK started"); 2001 // DHK = d1(IR, 3, 0) 2002 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2003 sm_aes128_state = SM_AES128_ACTIVE; 2004 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2005 return true; 2006 } 2007 break; 2008 default: 2009 break; 2010 } 2011 return false; 2012 } 2013 2014 // random address updates 2015 static bool sm_run_rau(void){ 2016 switch (rau_state){ 2017 case RAU_GET_RANDOM: 2018 rau_state = RAU_W4_RANDOM; 2019 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2020 return true; 2021 case RAU_GET_ENC: 2022 // already busy? 2023 if (sm_aes128_state == SM_AES128_IDLE) { 2024 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2025 sm_aes128_state = SM_AES128_ACTIVE; 2026 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2027 return true; 2028 } 2029 break; 2030 case RAU_SET_ADDRESS: 2031 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2032 rau_state = RAU_IDLE; 2033 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2034 return true; 2035 default: 2036 break; 2037 } 2038 return false; 2039 } 2040 2041 // CSRK Lookup 2042 static bool sm_run_csrk(void){ 2043 btstack_linked_list_iterator_t it; 2044 2045 // -- if csrk lookup ready, find connection that require csrk lookup 2046 if (sm_address_resolution_idle()){ 2047 hci_connections_get_iterator(&it); 2048 while(btstack_linked_list_iterator_has_next(&it)){ 2049 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2050 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2051 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2052 // and start lookup 2053 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); 2054 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2055 break; 2056 } 2057 } 2058 } 2059 2060 // -- if csrk lookup ready, resolved addresses for received addresses 2061 if (sm_address_resolution_idle()) { 2062 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2063 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2064 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2065 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2066 btstack_memory_sm_lookup_entry_free(entry); 2067 } 2068 } 2069 2070 // -- Continue with CSRK device lookup by public or resolvable private address 2071 if (!sm_address_resolution_idle()){ 2072 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2073 while (sm_address_resolution_test < le_device_db_max_count()){ 2074 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2075 bd_addr_t addr; 2076 sm_key_t irk; 2077 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2078 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2079 2080 // skip unused entries 2081 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2082 sm_address_resolution_test++; 2083 continue; 2084 } 2085 2086 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2087 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2088 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2089 break; 2090 } 2091 2092 // if connection type is public, it must be a different one 2093 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2094 sm_address_resolution_test++; 2095 continue; 2096 } 2097 2098 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2099 2100 log_info("LE Device Lookup: calculate AH"); 2101 log_info_key("IRK", irk); 2102 2103 (void)memcpy(sm_aes128_key, irk, 16); 2104 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2105 sm_address_resolution_ah_calculation_active = 1; 2106 sm_aes128_state = SM_AES128_ACTIVE; 2107 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2108 return true; 2109 } 2110 2111 if (sm_address_resolution_test >= le_device_db_max_count()){ 2112 log_info("LE Device Lookup: not found"); 2113 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2114 } 2115 } 2116 return false; 2117 } 2118 2119 // SC OOB 2120 static bool sm_run_oob(void){ 2121 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2122 switch (sm_sc_oob_state){ 2123 case SM_SC_OOB_W2_CALC_CONFIRM: 2124 if (!sm_cmac_ready()) break; 2125 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2126 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2127 return true; 2128 default: 2129 break; 2130 } 2131 #endif 2132 return false; 2133 } 2134 2135 // handle basic actions that don't requires the full context 2136 static bool sm_run_basic(void){ 2137 btstack_linked_list_iterator_t it; 2138 hci_connections_get_iterator(&it); 2139 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2140 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2141 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2142 switch(sm_connection->sm_engine_state){ 2143 // responder side 2144 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2145 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2146 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2147 return true; 2148 2149 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2150 case SM_SC_RECEIVED_LTK_REQUEST: 2151 switch (sm_connection->sm_irk_lookup_state){ 2152 case IRK_LOOKUP_FAILED: 2153 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2154 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2155 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2156 return true; 2157 default: 2158 break; 2159 } 2160 break; 2161 #endif 2162 default: 2163 break; 2164 } 2165 } 2166 return false; 2167 } 2168 2169 static void sm_run_activate_connection(void){ 2170 // Find connections that requires setup context and make active if no other is locked 2171 btstack_linked_list_iterator_t it; 2172 hci_connections_get_iterator(&it); 2173 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2174 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2175 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2176 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2177 int done = 1; 2178 int err; 2179 UNUSED(err); 2180 2181 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2182 // assert ec key is ready 2183 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2184 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2185 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2186 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2187 sm_ec_generate_new_key(); 2188 } 2189 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2190 continue; 2191 } 2192 } 2193 #endif 2194 2195 switch (sm_connection->sm_engine_state) { 2196 #ifdef ENABLE_LE_PERIPHERAL 2197 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2198 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2199 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2201 case SM_SC_RECEIVED_LTK_REQUEST: 2202 #endif 2203 #endif 2204 #ifdef ENABLE_LE_CENTRAL 2205 case SM_INITIATOR_PH0_HAS_LTK: 2206 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2207 #endif 2208 // just lock context 2209 break; 2210 default: 2211 done = 0; 2212 break; 2213 } 2214 if (done){ 2215 sm_active_connection_handle = sm_connection->sm_handle; 2216 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); 2217 } 2218 } 2219 } 2220 2221 static void sm_run(void){ 2222 2223 // assert that stack has already bootet 2224 if (hci_get_state() != HCI_STATE_WORKING) return; 2225 2226 // assert that we can send at least commands 2227 if (!hci_can_send_command_packet_now()) return; 2228 2229 // pause until IR/ER are ready 2230 if (sm_persistent_keys_random_active) return; 2231 2232 bool done; 2233 2234 // 2235 // non-connection related behaviour 2236 // 2237 2238 done = sm_run_dpkg(); 2239 if (done) return; 2240 2241 done = sm_run_rau(); 2242 if (done) return; 2243 2244 done = sm_run_csrk(); 2245 if (done) return; 2246 2247 done = sm_run_oob(); 2248 if (done) return; 2249 2250 // assert that we can send at least commands - cmd might have been sent by crypto engine 2251 if (!hci_can_send_command_packet_now()) return; 2252 2253 // handle basic actions that don't requires the full context 2254 done = sm_run_basic(); 2255 if (done) return; 2256 2257 // 2258 // active connection handling 2259 // -- use loop to handle next connection if lock on setup context is released 2260 2261 while (true) { 2262 2263 sm_run_activate_connection(); 2264 2265 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2266 2267 // 2268 // active connection handling 2269 // 2270 2271 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2272 if (!connection) { 2273 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2274 return; 2275 } 2276 2277 // assert that we could send a SM PDU - not needed for all of the following 2278 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2279 log_info("cannot send now, requesting can send now event"); 2280 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2281 return; 2282 } 2283 2284 // send keypress notifications 2285 if (setup->sm_keypress_notification){ 2286 int i; 2287 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2288 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2289 uint8_t action = 0; 2290 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2291 if (flags & (1u<<i)){ 2292 int clear_flag = 1; 2293 switch (i){ 2294 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2295 case SM_KEYPRESS_PASSKEY_CLEARED: 2296 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2297 default: 2298 break; 2299 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2300 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2301 num_actions--; 2302 clear_flag = num_actions == 0u; 2303 break; 2304 } 2305 if (clear_flag){ 2306 flags &= ~(1<<i); 2307 } 2308 action = i; 2309 break; 2310 } 2311 } 2312 setup->sm_keypress_notification = (num_actions << 5) | flags; 2313 2314 // send keypress notification 2315 uint8_t buffer[2]; 2316 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2317 buffer[1] = action; 2318 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2319 2320 // try 2321 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2322 return; 2323 } 2324 2325 int key_distribution_flags; 2326 UNUSED(key_distribution_flags); 2327 int err; 2328 UNUSED(err); 2329 2330 log_info("sm_run: state %u", connection->sm_engine_state); 2331 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2332 log_info("sm_run // cannot send"); 2333 } 2334 switch (connection->sm_engine_state){ 2335 2336 // general 2337 case SM_GENERAL_SEND_PAIRING_FAILED: { 2338 uint8_t buffer[2]; 2339 buffer[0] = SM_CODE_PAIRING_FAILED; 2340 buffer[1] = setup->sm_pairing_failed_reason; 2341 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2342 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2343 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2344 sm_done_for_handle(connection->sm_handle); 2345 break; 2346 } 2347 2348 // secure connections, initiator + responding states 2349 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2350 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2351 if (!sm_cmac_ready()) break; 2352 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2353 sm_sc_calculate_local_confirm(connection); 2354 break; 2355 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2356 if (!sm_cmac_ready()) break; 2357 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2358 sm_sc_calculate_remote_confirm(connection); 2359 break; 2360 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2361 if (!sm_cmac_ready()) break; 2362 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2363 sm_sc_calculate_f6_for_dhkey_check(connection); 2364 break; 2365 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2366 if (!sm_cmac_ready()) break; 2367 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2368 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2369 break; 2370 case SM_SC_W2_CALCULATE_F5_SALT: 2371 if (!sm_cmac_ready()) break; 2372 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2373 f5_calculate_salt(connection); 2374 break; 2375 case SM_SC_W2_CALCULATE_F5_MACKEY: 2376 if (!sm_cmac_ready()) break; 2377 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2378 f5_calculate_mackey(connection); 2379 break; 2380 case SM_SC_W2_CALCULATE_F5_LTK: 2381 if (!sm_cmac_ready()) break; 2382 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2383 f5_calculate_ltk(connection); 2384 break; 2385 case SM_SC_W2_CALCULATE_G2: 2386 if (!sm_cmac_ready()) break; 2387 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2388 g2_calculate(connection); 2389 break; 2390 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2391 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2392 if (!sm_cmac_ready()) break; 2393 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2394 h6_calculate_ilk(connection); 2395 break; 2396 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2397 if (!sm_cmac_ready()) break; 2398 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2399 h6_calculate_br_edr_link_key(connection); 2400 break; 2401 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2402 if (!sm_cmac_ready()) break; 2403 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2404 h7_calculate_ilk(connection); 2405 break; 2406 #endif 2407 #endif 2408 2409 #ifdef ENABLE_LE_CENTRAL 2410 // initiator side 2411 2412 case SM_INITIATOR_PH0_HAS_LTK: { 2413 sm_reset_setup(); 2414 sm_load_security_info(connection); 2415 2416 sm_key_t peer_ltk_flipped; 2417 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2418 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2419 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2420 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2421 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2422 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2423 return; 2424 } 2425 2426 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2427 sm_reset_setup(); 2428 sm_init_setup(connection); 2429 sm_timeout_start(connection); 2430 2431 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2432 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2433 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2434 sm_timeout_reset(connection); 2435 break; 2436 #endif 2437 2438 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2439 2440 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2441 int trigger_user_response = 0; 2442 int trigger_start_calculating_local_confirm = 0; 2443 uint8_t buffer[65]; 2444 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2445 // 2446 reverse_256(&ec_q[0], &buffer[1]); 2447 reverse_256(&ec_q[32], &buffer[33]); 2448 2449 #ifdef ENABLE_TESTING_SUPPORT 2450 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2451 log_info("testing_support: invalidating public key"); 2452 // flip single bit of public key coordinate 2453 buffer[1] ^= 1; 2454 } 2455 #endif 2456 2457 // stk generation method 2458 // passkey entry: notify app to show passkey or to request passkey 2459 switch (setup->sm_stk_generation_method){ 2460 case JUST_WORKS: 2461 case NUMERIC_COMPARISON: 2462 if (IS_RESPONDER(connection->sm_role)){ 2463 // responder 2464 trigger_start_calculating_local_confirm = 1; 2465 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2466 } else { 2467 // initiator 2468 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2469 } 2470 break; 2471 case PK_INIT_INPUT: 2472 case PK_RESP_INPUT: 2473 case PK_BOTH_INPUT: 2474 // use random TK for display 2475 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2476 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2477 setup->sm_passkey_bit = 0; 2478 2479 if (IS_RESPONDER(connection->sm_role)){ 2480 // responder 2481 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2482 } else { 2483 // initiator 2484 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2485 } 2486 trigger_user_response = 1; 2487 break; 2488 case OOB: 2489 if (IS_RESPONDER(connection->sm_role)){ 2490 // responder 2491 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2492 } else { 2493 // initiator 2494 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2495 } 2496 break; 2497 default: 2498 btstack_assert(false); 2499 break; 2500 } 2501 2502 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2503 sm_timeout_reset(connection); 2504 2505 // trigger user response and calc confirm after sending pdu 2506 if (trigger_user_response){ 2507 sm_trigger_user_response(connection); 2508 } 2509 if (trigger_start_calculating_local_confirm){ 2510 sm_sc_start_calculating_local_confirm(connection); 2511 } 2512 break; 2513 } 2514 case SM_SC_SEND_CONFIRMATION: { 2515 uint8_t buffer[17]; 2516 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2517 reverse_128(setup->sm_local_confirm, &buffer[1]); 2518 if (IS_RESPONDER(connection->sm_role)){ 2519 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2520 } else { 2521 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2522 } 2523 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2524 sm_timeout_reset(connection); 2525 break; 2526 } 2527 case SM_SC_SEND_PAIRING_RANDOM: { 2528 uint8_t buffer[17]; 2529 buffer[0] = SM_CODE_PAIRING_RANDOM; 2530 reverse_128(setup->sm_local_nonce, &buffer[1]); 2531 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2532 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2533 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2534 if (IS_RESPONDER(connection->sm_role)){ 2535 // responder 2536 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2537 } else { 2538 // initiator 2539 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2540 } 2541 } else { 2542 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2543 if (IS_RESPONDER(connection->sm_role)){ 2544 // responder 2545 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2546 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2547 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2548 } else { 2549 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2550 sm_sc_prepare_dhkey_check(connection); 2551 } 2552 } else { 2553 // initiator 2554 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2555 } 2556 } 2557 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2558 sm_timeout_reset(connection); 2559 break; 2560 } 2561 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2562 uint8_t buffer[17]; 2563 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2564 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2565 2566 if (IS_RESPONDER(connection->sm_role)){ 2567 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2568 } else { 2569 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2570 } 2571 2572 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2573 sm_timeout_reset(connection); 2574 break; 2575 } 2576 2577 #endif 2578 2579 #ifdef ENABLE_LE_PERIPHERAL 2580 2581 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2582 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2583 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2584 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2585 sm_timeout_start(connection); 2586 break; 2587 } 2588 2589 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2590 case SM_SC_RECEIVED_LTK_REQUEST: 2591 switch (connection->sm_irk_lookup_state){ 2592 case IRK_LOOKUP_SUCCEEDED: 2593 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2594 // start using context by loading security info 2595 sm_reset_setup(); 2596 sm_load_security_info(connection); 2597 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2598 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2599 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2600 sm_trigger_run(); 2601 break; 2602 } 2603 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2604 connection->sm_engine_state = SM_RESPONDER_IDLE; 2605 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2606 return; 2607 default: 2608 // just wait until IRK lookup is completed 2609 break; 2610 } 2611 break; 2612 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2613 2614 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2615 sm_reset_setup(); 2616 sm_init_setup(connection); 2617 // recover pairing request 2618 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2619 err = sm_stk_generation_init(connection); 2620 2621 #ifdef ENABLE_TESTING_SUPPORT 2622 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2623 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2624 err = test_pairing_failure; 2625 } 2626 #endif 2627 if (err){ 2628 setup->sm_pairing_failed_reason = err; 2629 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2630 sm_trigger_run(); 2631 break; 2632 } 2633 2634 sm_timeout_start(connection); 2635 2636 // generate random number first, if we need to show passkey, otherwise send response 2637 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2638 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2639 break; 2640 } 2641 2642 /* fall through */ 2643 2644 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2645 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2646 2647 // start with initiator key dist flags 2648 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2649 2650 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2651 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2652 if (setup->sm_use_secure_connections){ 2653 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2654 } 2655 #endif 2656 // setup in response 2657 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); 2658 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); 2659 2660 // update key distribution after ENC was dropped 2661 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2662 2663 if (setup->sm_use_secure_connections){ 2664 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2665 } else { 2666 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2667 } 2668 2669 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2670 sm_timeout_reset(connection); 2671 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2672 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2673 sm_trigger_user_response(connection); 2674 } 2675 return; 2676 #endif 2677 2678 case SM_PH2_SEND_PAIRING_RANDOM: { 2679 uint8_t buffer[17]; 2680 buffer[0] = SM_CODE_PAIRING_RANDOM; 2681 reverse_128(setup->sm_local_random, &buffer[1]); 2682 if (IS_RESPONDER(connection->sm_role)){ 2683 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2684 } else { 2685 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2686 } 2687 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2688 sm_timeout_reset(connection); 2689 break; 2690 } 2691 2692 case SM_PH2_C1_GET_ENC_A: 2693 // already busy? 2694 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2695 // calculate confirm using aes128 engine - step 1 2696 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); 2697 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2698 sm_aes128_state = SM_AES128_ACTIVE; 2699 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); 2700 break; 2701 2702 case SM_PH2_C1_GET_ENC_C: 2703 // already busy? 2704 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2705 // calculate m_confirm using aes128 engine - step 1 2706 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); 2707 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2708 sm_aes128_state = SM_AES128_ACTIVE; 2709 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); 2710 break; 2711 2712 case SM_PH2_CALC_STK: 2713 // already busy? 2714 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2715 // calculate STK 2716 if (IS_RESPONDER(connection->sm_role)){ 2717 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2718 } else { 2719 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2720 } 2721 connection->sm_engine_state = SM_PH2_W4_STK; 2722 sm_aes128_state = SM_AES128_ACTIVE; 2723 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); 2724 break; 2725 2726 case SM_PH3_Y_GET_ENC: 2727 // already busy? 2728 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2729 // PH3B2 - calculate Y from - enc 2730 2731 // dm helper (was sm_dm_r_prime) 2732 // r' = padding || r 2733 // r - 64 bit value 2734 memset(&sm_aes128_plaintext[0], 0, 8); 2735 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2736 2737 // Y = dm(DHK, Rand) 2738 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2739 sm_aes128_state = SM_AES128_ACTIVE; 2740 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); 2741 break; 2742 2743 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2744 uint8_t buffer[17]; 2745 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2746 reverse_128(setup->sm_local_confirm, &buffer[1]); 2747 if (IS_RESPONDER(connection->sm_role)){ 2748 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2749 } else { 2750 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2751 } 2752 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2753 sm_timeout_reset(connection); 2754 return; 2755 } 2756 #ifdef ENABLE_LE_PERIPHERAL 2757 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2758 sm_key_t stk_flipped; 2759 reverse_128(setup->sm_ltk, stk_flipped); 2760 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2761 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2762 return; 2763 } 2764 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2765 sm_key_t ltk_flipped; 2766 reverse_128(setup->sm_ltk, ltk_flipped); 2767 connection->sm_engine_state = SM_RESPONDER_IDLE; 2768 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2769 sm_done_for_handle(connection->sm_handle); 2770 return; 2771 } 2772 2773 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2774 // already busy? 2775 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2776 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2777 2778 sm_reset_setup(); 2779 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2780 2781 // dm helper (was sm_dm_r_prime) 2782 // r' = padding || r 2783 // r - 64 bit value 2784 memset(&sm_aes128_plaintext[0], 0, 8); 2785 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2786 2787 // Y = dm(DHK, Rand) 2788 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2789 sm_aes128_state = SM_AES128_ACTIVE; 2790 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); 2791 return; 2792 #endif 2793 #ifdef ENABLE_LE_CENTRAL 2794 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2795 sm_key_t stk_flipped; 2796 reverse_128(setup->sm_ltk, stk_flipped); 2797 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2798 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2799 return; 2800 } 2801 #endif 2802 2803 case SM_PH3_DISTRIBUTE_KEYS: 2804 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2805 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2806 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2807 uint8_t buffer[17]; 2808 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2809 reverse_128(setup->sm_ltk, &buffer[1]); 2810 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2811 sm_timeout_reset(connection); 2812 return; 2813 } 2814 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2815 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2816 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2817 uint8_t buffer[11]; 2818 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2819 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2820 reverse_64(setup->sm_local_rand, &buffer[3]); 2821 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2822 sm_timeout_reset(connection); 2823 return; 2824 } 2825 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2826 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2827 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2828 uint8_t buffer[17]; 2829 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2830 reverse_128(sm_persistent_irk, &buffer[1]); 2831 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2832 sm_timeout_reset(connection); 2833 return; 2834 } 2835 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2836 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2837 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2838 bd_addr_t local_address; 2839 uint8_t buffer[8]; 2840 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2841 switch (gap_random_address_get_mode()){ 2842 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2843 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2844 // public or static random 2845 gap_le_get_own_address(&buffer[1], local_address); 2846 break; 2847 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2848 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2849 // fallback to public 2850 gap_local_bd_addr(local_address); 2851 buffer[1] = 0; 2852 break; 2853 default: 2854 btstack_assert(false); 2855 break; 2856 } 2857 reverse_bd_addr(local_address, &buffer[2]); 2858 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2859 sm_timeout_reset(connection); 2860 return; 2861 } 2862 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2863 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2864 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2865 2866 #ifdef ENABLE_LE_SIGNED_WRITE 2867 // hack to reproduce test runs 2868 if (test_use_fixed_local_csrk){ 2869 memset(setup->sm_local_csrk, 0xcc, 16); 2870 } 2871 2872 // store local CSRK 2873 if (setup->sm_le_device_index >= 0){ 2874 log_info("sm: store local CSRK"); 2875 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2876 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2877 } 2878 #endif 2879 2880 uint8_t buffer[17]; 2881 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2882 reverse_128(setup->sm_local_csrk, &buffer[1]); 2883 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2884 sm_timeout_reset(connection); 2885 return; 2886 } 2887 2888 // keys are sent 2889 if (IS_RESPONDER(connection->sm_role)){ 2890 // slave -> receive master keys if any 2891 if (sm_key_distribution_all_received(connection)){ 2892 sm_key_distribution_handle_all_received(connection); 2893 connection->sm_engine_state = SM_RESPONDER_IDLE; 2894 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2895 sm_done_for_handle(connection->sm_handle); 2896 } else { 2897 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2898 } 2899 } else { 2900 sm_master_pairing_success(connection); 2901 } 2902 break; 2903 2904 default: 2905 break; 2906 } 2907 2908 // check again if active connection was released 2909 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2910 } 2911 } 2912 2913 // sm_aes128_state stays active 2914 static void sm_handle_encryption_result_enc_a(void *arg){ 2915 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2916 sm_aes128_state = SM_AES128_IDLE; 2917 2918 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2919 if (connection == NULL) return; 2920 2921 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2922 sm_aes128_state = SM_AES128_ACTIVE; 2923 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); 2924 } 2925 2926 static void sm_handle_encryption_result_enc_b(void *arg){ 2927 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2928 sm_aes128_state = SM_AES128_IDLE; 2929 2930 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2931 if (connection == NULL) return; 2932 2933 log_info_key("c1!", setup->sm_local_confirm); 2934 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2935 sm_trigger_run(); 2936 } 2937 2938 // sm_aes128_state stays active 2939 static void sm_handle_encryption_result_enc_c(void *arg){ 2940 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2941 sm_aes128_state = SM_AES128_IDLE; 2942 2943 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2944 if (connection == NULL) return; 2945 2946 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2947 sm_aes128_state = SM_AES128_ACTIVE; 2948 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); 2949 } 2950 2951 static void sm_handle_encryption_result_enc_d(void * arg){ 2952 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2953 sm_aes128_state = SM_AES128_IDLE; 2954 2955 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2956 if (connection == NULL) return; 2957 2958 log_info_key("c1!", sm_aes128_ciphertext); 2959 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2960 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2961 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2962 sm_trigger_run(); 2963 return; 2964 } 2965 if (IS_RESPONDER(connection->sm_role)){ 2966 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2967 sm_trigger_run(); 2968 } else { 2969 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2970 sm_aes128_state = SM_AES128_ACTIVE; 2971 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); 2972 } 2973 } 2974 2975 static void sm_handle_encryption_result_enc_stk(void *arg){ 2976 sm_aes128_state = SM_AES128_IDLE; 2977 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2978 2979 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2980 if (connection == NULL) return; 2981 2982 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2983 log_info_key("stk", setup->sm_ltk); 2984 if (IS_RESPONDER(connection->sm_role)){ 2985 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2986 } else { 2987 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2988 } 2989 sm_trigger_run(); 2990 } 2991 2992 // sm_aes128_state stays active 2993 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2994 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2995 sm_aes128_state = SM_AES128_IDLE; 2996 2997 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2998 if (connection == NULL) return; 2999 3000 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3001 log_info_hex16("y", setup->sm_local_y); 3002 // PH3B3 - calculate EDIV 3003 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3004 log_info_hex16("ediv", setup->sm_local_ediv); 3005 // PH3B4 - calculate LTK - enc 3006 // LTK = d1(ER, DIV, 0)) 3007 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3008 sm_aes128_state = SM_AES128_ACTIVE; 3009 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); 3010 } 3011 3012 #ifdef ENABLE_LE_PERIPHERAL 3013 // sm_aes128_state stays active 3014 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3015 sm_aes128_state = SM_AES128_IDLE; 3016 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3017 3018 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3019 if (connection == NULL) return; 3020 3021 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3022 log_info_hex16("y", setup->sm_local_y); 3023 3024 // PH3B3 - calculate DIV 3025 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3026 log_info_hex16("ediv", setup->sm_local_ediv); 3027 // PH3B4 - calculate LTK - enc 3028 // LTK = d1(ER, DIV, 0)) 3029 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3030 sm_aes128_state = SM_AES128_ACTIVE; 3031 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); 3032 } 3033 #endif 3034 3035 // sm_aes128_state stays active 3036 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3037 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3038 sm_aes128_state = SM_AES128_IDLE; 3039 3040 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3041 if (connection == NULL) return; 3042 3043 log_info_key("ltk", setup->sm_ltk); 3044 // calc CSRK next 3045 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3046 sm_aes128_state = SM_AES128_ACTIVE; 3047 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); 3048 } 3049 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3050 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3051 // requirements to derive link key from LE: 3052 // - use secure connections 3053 if (setup->sm_use_secure_connections == 0) return false; 3054 // - bonding needs to be enabled: 3055 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; 3056 if (!bonding_enabled) return false; 3057 // - need identity address 3058 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3059 if (!have_identity_address_info) return false; 3060 // - 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) 3061 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3062 // If SC is authenticated, we consider it safe to overwrite a stored key. 3063 // 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. 3064 uint8_t link_key[16]; 3065 link_key_type_t link_key_type; 3066 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3067 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3068 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3069 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3070 return false; 3071 } 3072 // get started (all of the above are true) 3073 return true; 3074 #else 3075 UNUSED(sm_connection); 3076 return false; 3077 #endif 3078 } 3079 3080 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3081 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3082 sm_aes128_state = SM_AES128_IDLE; 3083 3084 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3085 if (connection == NULL) return; 3086 3087 sm_aes128_state = SM_AES128_IDLE; 3088 log_info_key("csrk", setup->sm_local_csrk); 3089 if (setup->sm_key_distribution_send_set){ 3090 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3091 } else { 3092 // no keys to send, just continue 3093 if (IS_RESPONDER(connection->sm_role)){ 3094 // slave -> receive master keys 3095 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3096 } else { 3097 if (sm_ctkd_from_le(connection)){ 3098 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; 3099 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3100 } else { 3101 sm_master_pairing_success(connection); 3102 } 3103 } 3104 } 3105 sm_trigger_run(); 3106 } 3107 3108 #ifdef ENABLE_LE_PERIPHERAL 3109 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3110 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3111 sm_aes128_state = SM_AES128_IDLE; 3112 3113 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3114 if (connection == NULL) return; 3115 3116 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3117 log_info_key("ltk", setup->sm_ltk); 3118 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3119 sm_trigger_run(); 3120 } 3121 #endif 3122 3123 static void sm_handle_encryption_result_address_resolution(void *arg){ 3124 UNUSED(arg); 3125 sm_aes128_state = SM_AES128_IDLE; 3126 3127 sm_address_resolution_ah_calculation_active = 0; 3128 // compare calulated address against connecting device 3129 uint8_t * hash = &sm_aes128_ciphertext[13]; 3130 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3131 log_info("LE Device Lookup: matched resolvable private address"); 3132 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3133 sm_trigger_run(); 3134 return; 3135 } 3136 // no match, try next 3137 sm_address_resolution_test++; 3138 sm_trigger_run(); 3139 } 3140 3141 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3142 UNUSED(arg); 3143 sm_aes128_state = SM_AES128_IDLE; 3144 3145 log_info_key("irk", sm_persistent_irk); 3146 dkg_state = DKG_CALC_DHK; 3147 sm_trigger_run(); 3148 } 3149 3150 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3151 UNUSED(arg); 3152 sm_aes128_state = SM_AES128_IDLE; 3153 3154 log_info_key("dhk", sm_persistent_dhk); 3155 dkg_state = DKG_READY; 3156 sm_trigger_run(); 3157 } 3158 3159 static void sm_handle_encryption_result_rau(void *arg){ 3160 UNUSED(arg); 3161 sm_aes128_state = SM_AES128_IDLE; 3162 3163 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3164 rau_state = RAU_SET_ADDRESS; 3165 sm_trigger_run(); 3166 } 3167 3168 static void sm_handle_random_result_rau(void * arg){ 3169 UNUSED(arg); 3170 // non-resolvable vs. resolvable 3171 switch (gap_random_adress_type){ 3172 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3173 // resolvable: use random as prand and calc address hash 3174 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3175 sm_random_address[0u] &= 0x3fu; 3176 sm_random_address[0u] |= 0x40u; 3177 rau_state = RAU_GET_ENC; 3178 break; 3179 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3180 default: 3181 // "The two most significant bits of the address shall be equal to ‘0’"" 3182 sm_random_address[0u] &= 0x3fu; 3183 rau_state = RAU_SET_ADDRESS; 3184 break; 3185 } 3186 sm_trigger_run(); 3187 } 3188 3189 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3190 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3191 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3192 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3193 if (connection == NULL) return; 3194 3195 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3196 sm_trigger_run(); 3197 } 3198 3199 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3200 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3201 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3202 if (connection == NULL) return; 3203 3204 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3205 sm_trigger_run(); 3206 } 3207 #endif 3208 3209 static void sm_handle_random_result_ph2_random(void * arg){ 3210 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3211 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3212 if (connection == NULL) return; 3213 3214 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3215 sm_trigger_run(); 3216 } 3217 3218 static void sm_handle_random_result_ph2_tk(void * arg){ 3219 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3220 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3221 if (connection == NULL) return; 3222 3223 sm_reset_tk(); 3224 uint32_t tk; 3225 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3226 // map random to 0-999999 without speding much cycles on a modulus operation 3227 tk = little_endian_read_32(sm_random_data,0); 3228 tk = tk & 0xfffff; // 1048575 3229 if (tk >= 999999u){ 3230 tk = tk - 999999u; 3231 } 3232 } else { 3233 // override with pre-defined passkey 3234 tk = sm_fixed_passkey_in_display_role; 3235 } 3236 big_endian_store_32(setup->sm_tk, 12, tk); 3237 if (IS_RESPONDER(connection->sm_role)){ 3238 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3239 } else { 3240 if (setup->sm_use_secure_connections){ 3241 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3242 } else { 3243 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3244 sm_trigger_user_response(connection); 3245 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3246 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3247 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); 3248 } 3249 } 3250 } 3251 sm_trigger_run(); 3252 } 3253 3254 static void sm_handle_random_result_ph3_div(void * arg){ 3255 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3256 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3257 if (connection == NULL) return; 3258 3259 // use 16 bit from random value as div 3260 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3261 log_info_hex16("div", setup->sm_local_div); 3262 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3263 sm_trigger_run(); 3264 } 3265 3266 static void sm_handle_random_result_ph3_random(void * arg){ 3267 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3268 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3269 if (connection == NULL) return; 3270 3271 reverse_64(sm_random_data, setup->sm_local_rand); 3272 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3273 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3274 // no db for authenticated flag hack: store flag in bit 4 of LSB 3275 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3276 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3277 } 3278 static void sm_validate_er_ir(void){ 3279 // warn about default ER/IR 3280 int warning = 0; 3281 if (sm_ir_is_default()){ 3282 warning = 1; 3283 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3284 } 3285 if (sm_er_is_default()){ 3286 warning = 1; 3287 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3288 } 3289 if (warning) { 3290 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3291 } 3292 } 3293 3294 static void sm_handle_random_result_ir(void *arg){ 3295 sm_persistent_keys_random_active = 0; 3296 if (arg){ 3297 // key generated, store in tlv 3298 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3299 log_info("Generated IR key. Store in TLV status: %d", status); 3300 UNUSED(status); 3301 } 3302 log_info_key("IR", sm_persistent_ir); 3303 dkg_state = DKG_CALC_IRK; 3304 3305 if (test_use_fixed_local_irk){ 3306 log_info_key("IRK", sm_persistent_irk); 3307 dkg_state = DKG_CALC_DHK; 3308 } 3309 3310 sm_trigger_run(); 3311 } 3312 3313 static void sm_handle_random_result_er(void *arg){ 3314 sm_persistent_keys_random_active = 0; 3315 if (arg){ 3316 // key generated, store in tlv 3317 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3318 log_info("Generated ER key. Store in TLV status: %d", status); 3319 UNUSED(status); 3320 } 3321 log_info_key("ER", sm_persistent_er); 3322 3323 // try load ir 3324 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3325 if (key_size == 16){ 3326 // ok, let's continue 3327 log_info("IR from TLV"); 3328 sm_handle_random_result_ir( NULL ); 3329 } else { 3330 // invalid, generate new random one 3331 sm_persistent_keys_random_active = 1; 3332 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3333 } 3334 } 3335 3336 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3337 3338 UNUSED(channel); // ok: there is no channel 3339 UNUSED(size); // ok: fixed format HCI events 3340 3341 sm_connection_t * sm_conn; 3342 hci_con_handle_t con_handle; 3343 uint8_t status; 3344 switch (packet_type) { 3345 3346 case HCI_EVENT_PACKET: 3347 switch (hci_event_packet_get_type(packet)) { 3348 3349 case BTSTACK_EVENT_STATE: 3350 // bt stack activated, get started 3351 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3352 log_info("HCI Working!"); 3353 3354 // setup IR/ER with TLV 3355 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3356 if (sm_tlv_impl){ 3357 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3358 if (key_size == 16){ 3359 // ok, let's continue 3360 log_info("ER from TLV"); 3361 sm_handle_random_result_er( NULL ); 3362 } else { 3363 // invalid, generate random one 3364 sm_persistent_keys_random_active = 1; 3365 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3366 } 3367 } else { 3368 sm_validate_er_ir(); 3369 dkg_state = DKG_CALC_IRK; 3370 3371 if (test_use_fixed_local_irk){ 3372 log_info_key("IRK", sm_persistent_irk); 3373 dkg_state = DKG_CALC_DHK; 3374 } 3375 } 3376 3377 // restart random address updates after power cycle 3378 gap_random_address_set_mode(gap_random_adress_type); 3379 } 3380 break; 3381 3382 case HCI_EVENT_LE_META: 3383 switch (packet[2]) { 3384 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3385 3386 log_info("sm: connected"); 3387 3388 if (packet[3]) return; // connection failed 3389 3390 con_handle = little_endian_read_16(packet, 4); 3391 sm_conn = sm_get_connection_for_handle(con_handle); 3392 if (!sm_conn) break; 3393 3394 sm_conn->sm_handle = con_handle; 3395 sm_conn->sm_role = packet[6]; 3396 sm_conn->sm_peer_addr_type = packet[7]; 3397 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3398 3399 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3400 3401 // reset security properties 3402 sm_conn->sm_connection_encrypted = 0; 3403 sm_conn->sm_connection_authenticated = 0; 3404 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3405 sm_conn->sm_le_db_index = -1; 3406 3407 // prepare CSRK lookup (does not involve setup) 3408 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3409 3410 // just connected -> everything else happens in sm_run() 3411 if (IS_RESPONDER(sm_conn->sm_role)){ 3412 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3413 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3414 if (sm_slave_request_security) { 3415 // request security if requested by app 3416 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3417 } else { 3418 // otherwise, wait for pairing request 3419 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3420 } 3421 } 3422 break; 3423 } else { 3424 // master 3425 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3426 } 3427 break; 3428 3429 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3430 con_handle = little_endian_read_16(packet, 3); 3431 sm_conn = sm_get_connection_for_handle(con_handle); 3432 if (!sm_conn) break; 3433 3434 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3435 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3436 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3437 break; 3438 } 3439 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3440 // PH2 SEND LTK as we need to exchange keys in PH3 3441 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3442 break; 3443 } 3444 3445 // store rand and ediv 3446 reverse_64(&packet[5], sm_conn->sm_local_rand); 3447 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3448 3449 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3450 // potentially stored LTK is from the master 3451 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3452 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3453 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3454 break; 3455 } 3456 // additionally check if remote is in LE Device DB if requested 3457 switch(sm_conn->sm_irk_lookup_state){ 3458 case IRK_LOOKUP_FAILED: 3459 log_info("LTK Request: device not in device db"); 3460 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3461 break; 3462 case IRK_LOOKUP_SUCCEEDED: 3463 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3464 break; 3465 default: 3466 // wait for irk look doen 3467 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3468 break; 3469 } 3470 break; 3471 } 3472 3473 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3474 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3475 #else 3476 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3477 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3478 #endif 3479 break; 3480 3481 default: 3482 break; 3483 } 3484 break; 3485 3486 case HCI_EVENT_ENCRYPTION_CHANGE: 3487 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3488 sm_conn = sm_get_connection_for_handle(con_handle); 3489 if (!sm_conn) break; 3490 3491 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3492 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3493 sm_conn->sm_actual_encryption_key_size); 3494 log_info("event handler, state %u", sm_conn->sm_engine_state); 3495 3496 switch (sm_conn->sm_engine_state){ 3497 3498 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3499 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3500 if (sm_conn->sm_connection_encrypted) { 3501 status = ERROR_CODE_SUCCESS; 3502 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3503 } else { 3504 status = ERROR_CODE_AUTHENTICATION_FAILURE; 3505 // set state to 'TIMEOUT' to prevent further interaction with this 3506 // also, gap_reconnect_security_setup_active will return true 3507 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 3508 } 3509 3510 // emit re-encryption complete 3511 sm_reencryption_complete(sm_conn, status); 3512 3513 // notify client, if pairing was requested before 3514 if (sm_conn->sm_pairing_requested){ 3515 sm_conn->sm_pairing_requested = 0; 3516 sm_notify_client_status_reason(sm_conn, status, 0); 3517 } 3518 3519 sm_done_for_handle(sm_conn->sm_handle); 3520 3521 // abort/disconnect on authentication failure 3522 if (status == ERROR_CODE_AUTHENTICATION_FAILURE){ 3523 // gap disconnect with authentication failure 3524 hci_disconnect_security_block(con_handle); 3525 } 3526 break; 3527 3528 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3529 if (!sm_conn->sm_connection_encrypted) break; 3530 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3531 if (IS_RESPONDER(sm_conn->sm_role)){ 3532 // slave 3533 if (setup->sm_use_secure_connections){ 3534 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3535 } else { 3536 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); 3537 } 3538 } else { 3539 // master 3540 if (sm_key_distribution_all_received(sm_conn)){ 3541 // skip receiving keys as there are none 3542 sm_key_distribution_handle_all_received(sm_conn); 3543 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); 3544 } else { 3545 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3546 } 3547 } 3548 break; 3549 default: 3550 break; 3551 } 3552 break; 3553 3554 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3555 con_handle = little_endian_read_16(packet, 3); 3556 sm_conn = sm_get_connection_for_handle(con_handle); 3557 if (!sm_conn) break; 3558 3559 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3560 log_info("event handler, state %u", sm_conn->sm_engine_state); 3561 // continue if part of initial pairing 3562 switch (sm_conn->sm_engine_state){ 3563 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3564 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3565 sm_done_for_handle(sm_conn->sm_handle); 3566 break; 3567 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3568 if (IS_RESPONDER(sm_conn->sm_role)){ 3569 // slave 3570 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); 3571 } else { 3572 // master 3573 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3574 } 3575 break; 3576 default: 3577 break; 3578 } 3579 break; 3580 3581 3582 case HCI_EVENT_DISCONNECTION_COMPLETE: 3583 con_handle = little_endian_read_16(packet, 3); 3584 sm_done_for_handle(con_handle); 3585 sm_conn = sm_get_connection_for_handle(con_handle); 3586 if (!sm_conn) break; 3587 3588 // delete stored bonding on disconnect with authentication failure in ph0 3589 if ((sm_conn->sm_role == 0u) 3590 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3591 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3592 le_device_db_remove(sm_conn->sm_le_db_index); 3593 } 3594 3595 // pairing failed, if it was ongoing 3596 switch (sm_conn->sm_engine_state){ 3597 case SM_GENERAL_IDLE: 3598 case SM_INITIATOR_CONNECTED: 3599 case SM_RESPONDER_IDLE: 3600 break; 3601 default: 3602 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3603 break; 3604 } 3605 3606 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3607 sm_conn->sm_handle = 0; 3608 break; 3609 3610 case HCI_EVENT_COMMAND_COMPLETE: 3611 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3612 // set local addr for le device db 3613 bd_addr_t addr; 3614 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3615 le_device_db_set_local_bd_addr(addr); 3616 } 3617 break; 3618 default: 3619 break; 3620 } 3621 break; 3622 default: 3623 break; 3624 } 3625 3626 sm_run(); 3627 } 3628 3629 static inline int sm_calc_actual_encryption_key_size(int other){ 3630 if (other < sm_min_encryption_key_size) return 0; 3631 if (other < sm_max_encryption_key_size) return other; 3632 return sm_max_encryption_key_size; 3633 } 3634 3635 3636 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3637 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3638 switch (method){ 3639 case JUST_WORKS: 3640 case NUMERIC_COMPARISON: 3641 return 1; 3642 default: 3643 return 0; 3644 } 3645 } 3646 // responder 3647 3648 static int sm_passkey_used(stk_generation_method_t method){ 3649 switch (method){ 3650 case PK_RESP_INPUT: 3651 return 1; 3652 default: 3653 return 0; 3654 } 3655 } 3656 3657 static int sm_passkey_entry(stk_generation_method_t method){ 3658 switch (method){ 3659 case PK_RESP_INPUT: 3660 case PK_INIT_INPUT: 3661 case PK_BOTH_INPUT: 3662 return 1; 3663 default: 3664 return 0; 3665 } 3666 } 3667 3668 #endif 3669 3670 /** 3671 * @return ok 3672 */ 3673 static int sm_validate_stk_generation_method(void){ 3674 // check if STK generation method is acceptable by client 3675 switch (setup->sm_stk_generation_method){ 3676 case JUST_WORKS: 3677 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3678 case PK_RESP_INPUT: 3679 case PK_INIT_INPUT: 3680 case PK_BOTH_INPUT: 3681 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3682 case OOB: 3683 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3684 case NUMERIC_COMPARISON: 3685 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3686 default: 3687 return 0; 3688 } 3689 } 3690 3691 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3692 3693 // size of complete sm_pdu used to validate input 3694 static const uint8_t sm_pdu_size[] = { 3695 0, // 0x00 invalid opcode 3696 7, // 0x01 pairing request 3697 7, // 0x02 pairing response 3698 17, // 0x03 pairing confirm 3699 17, // 0x04 pairing random 3700 2, // 0x05 pairing failed 3701 17, // 0x06 encryption information 3702 11, // 0x07 master identification 3703 17, // 0x08 identification information 3704 8, // 0x09 identify address information 3705 17, // 0x0a signing information 3706 2, // 0x0b security request 3707 65, // 0x0c pairing public key 3708 17, // 0x0d pairing dhk check 3709 2, // 0x0e keypress notification 3710 }; 3711 3712 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3713 sm_run(); 3714 } 3715 3716 if (packet_type != SM_DATA_PACKET) return; 3717 if (size == 0u) return; 3718 3719 uint8_t sm_pdu_code = packet[0]; 3720 3721 // validate pdu size 3722 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3723 if (sm_pdu_size[sm_pdu_code] != size) return; 3724 3725 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3726 if (!sm_conn) return; 3727 3728 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3729 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3730 sm_done_for_handle(con_handle); 3731 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3732 return; 3733 } 3734 3735 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3736 3737 int err; 3738 UNUSED(err); 3739 3740 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3741 uint8_t buffer[5]; 3742 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3743 buffer[1] = 3; 3744 little_endian_store_16(buffer, 2, con_handle); 3745 buffer[4] = packet[1]; 3746 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3747 return; 3748 } 3749 3750 switch (sm_conn->sm_engine_state){ 3751 3752 // a sm timeout requires a new physical connection 3753 case SM_GENERAL_TIMEOUT: 3754 return; 3755 3756 #ifdef ENABLE_LE_CENTRAL 3757 3758 // Initiator 3759 case SM_INITIATOR_CONNECTED: 3760 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3761 sm_pdu_received_in_wrong_state(sm_conn); 3762 break; 3763 } 3764 3765 // IRK complete? 3766 int have_ltk; 3767 uint8_t ltk[16]; 3768 switch (sm_conn->sm_irk_lookup_state){ 3769 case IRK_LOOKUP_FAILED: 3770 // start pairing 3771 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3772 break; 3773 case IRK_LOOKUP_SUCCEEDED: 3774 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3775 have_ltk = !sm_is_null_key(ltk); 3776 log_info("central: security request - have_ltk %u", have_ltk); 3777 if (have_ltk){ 3778 // start re-encrypt 3779 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3780 } else { 3781 // start pairing 3782 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3783 } 3784 break; 3785 default: 3786 // otherwise, store security request 3787 sm_conn->sm_security_request_received = 1; 3788 break; 3789 } 3790 break; 3791 3792 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3793 // Core 5, Vol 3, Part H, 2.4.6: 3794 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3795 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3796 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3797 log_info("Ignoring Security Request"); 3798 break; 3799 } 3800 3801 // all other pdus are incorrect 3802 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3803 sm_pdu_received_in_wrong_state(sm_conn); 3804 break; 3805 } 3806 3807 // store pairing request 3808 (void)memcpy(&setup->sm_s_pres, packet, 3809 sizeof(sm_pairing_packet_t)); 3810 err = sm_stk_generation_init(sm_conn); 3811 3812 #ifdef ENABLE_TESTING_SUPPORT 3813 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3814 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3815 err = test_pairing_failure; 3816 } 3817 #endif 3818 3819 if (err){ 3820 setup->sm_pairing_failed_reason = err; 3821 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3822 break; 3823 } 3824 3825 // generate random number first, if we need to show passkey 3826 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3827 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); 3828 break; 3829 } 3830 3831 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3832 if (setup->sm_use_secure_connections){ 3833 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3834 if (setup->sm_stk_generation_method == JUST_WORKS){ 3835 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3836 sm_trigger_user_response(sm_conn); 3837 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3838 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3839 } 3840 } else { 3841 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3842 } 3843 break; 3844 } 3845 #endif 3846 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3847 sm_trigger_user_response(sm_conn); 3848 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3849 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3850 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); 3851 } 3852 break; 3853 3854 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3855 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3856 sm_pdu_received_in_wrong_state(sm_conn); 3857 break; 3858 } 3859 3860 // store s_confirm 3861 reverse_128(&packet[1], setup->sm_peer_confirm); 3862 3863 #ifdef ENABLE_TESTING_SUPPORT 3864 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3865 log_info("testing_support: reset confirm value"); 3866 memset(setup->sm_peer_confirm, 0, 16); 3867 } 3868 #endif 3869 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3870 break; 3871 3872 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3873 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3874 sm_pdu_received_in_wrong_state(sm_conn); 3875 break;; 3876 } 3877 3878 // received random value 3879 reverse_128(&packet[1], setup->sm_peer_random); 3880 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3881 break; 3882 #endif 3883 3884 #ifdef ENABLE_LE_PERIPHERAL 3885 // Responder 3886 case SM_RESPONDER_IDLE: 3887 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3888 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3889 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3890 sm_pdu_received_in_wrong_state(sm_conn); 3891 break;; 3892 } 3893 3894 // store pairing request 3895 (void)memcpy(&sm_conn->sm_m_preq, packet, 3896 sizeof(sm_pairing_packet_t)); 3897 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3898 break; 3899 #endif 3900 3901 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3902 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3903 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3904 sm_pdu_received_in_wrong_state(sm_conn); 3905 break; 3906 } 3907 3908 // store public key for DH Key calculation 3909 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3910 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3911 3912 // validate public key 3913 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3914 if (err){ 3915 log_error("sm: peer public key invalid %x", err); 3916 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3917 break; 3918 } 3919 3920 // start calculating dhkey 3921 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); 3922 3923 3924 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3925 if (IS_RESPONDER(sm_conn->sm_role)){ 3926 // responder 3927 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3928 } else { 3929 // initiator 3930 // stk generation method 3931 // passkey entry: notify app to show passkey or to request passkey 3932 switch (setup->sm_stk_generation_method){ 3933 case JUST_WORKS: 3934 case NUMERIC_COMPARISON: 3935 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3936 break; 3937 case PK_RESP_INPUT: 3938 sm_sc_start_calculating_local_confirm(sm_conn); 3939 break; 3940 case PK_INIT_INPUT: 3941 case PK_BOTH_INPUT: 3942 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3943 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3944 break; 3945 } 3946 sm_sc_start_calculating_local_confirm(sm_conn); 3947 break; 3948 case OOB: 3949 // generate Nx 3950 log_info("Generate Na"); 3951 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); 3952 break; 3953 default: 3954 btstack_assert(false); 3955 break; 3956 } 3957 } 3958 break; 3959 3960 case SM_SC_W4_CONFIRMATION: 3961 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3962 sm_pdu_received_in_wrong_state(sm_conn); 3963 break; 3964 } 3965 // received confirm value 3966 reverse_128(&packet[1], setup->sm_peer_confirm); 3967 3968 #ifdef ENABLE_TESTING_SUPPORT 3969 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3970 log_info("testing_support: reset confirm value"); 3971 memset(setup->sm_peer_confirm, 0, 16); 3972 } 3973 #endif 3974 if (IS_RESPONDER(sm_conn->sm_role)){ 3975 // responder 3976 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3977 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3978 // still waiting for passkey 3979 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3980 break; 3981 } 3982 } 3983 sm_sc_start_calculating_local_confirm(sm_conn); 3984 } else { 3985 // initiator 3986 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3987 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); 3988 } else { 3989 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3990 } 3991 } 3992 break; 3993 3994 case SM_SC_W4_PAIRING_RANDOM: 3995 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3996 sm_pdu_received_in_wrong_state(sm_conn); 3997 break; 3998 } 3999 4000 // received random value 4001 reverse_128(&packet[1], setup->sm_peer_nonce); 4002 4003 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4004 // only check for JUST WORK/NC in initiator role OR passkey entry 4005 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4006 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4007 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4008 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4009 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4010 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4011 break; 4012 } 4013 4014 // OOB 4015 if (setup->sm_stk_generation_method == OOB){ 4016 4017 // setup local random, set to zero if remote did not receive our data 4018 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4019 if (IS_RESPONDER(sm_conn->sm_role)){ 4020 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4021 log_info("Reset rb as A does not have OOB data"); 4022 memset(setup->sm_rb, 0, 16); 4023 } else { 4024 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4025 log_info("Use stored rb"); 4026 log_info_hexdump(setup->sm_rb, 16); 4027 } 4028 } else { 4029 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4030 log_info("Reset ra as B does not have OOB data"); 4031 memset(setup->sm_ra, 0, 16); 4032 } else { 4033 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4034 log_info("Use stored ra"); 4035 log_info_hexdump(setup->sm_ra, 16); 4036 } 4037 } 4038 4039 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4040 if (setup->sm_have_oob_data){ 4041 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4042 break; 4043 } 4044 } 4045 4046 // TODO: we only get here for Responder role with JW/NC 4047 sm_sc_state_after_receiving_random(sm_conn); 4048 break; 4049 4050 case SM_SC_W2_CALCULATE_G2: 4051 case SM_SC_W4_CALCULATE_G2: 4052 case SM_SC_W4_CALCULATE_DHKEY: 4053 case SM_SC_W2_CALCULATE_F5_SALT: 4054 case SM_SC_W4_CALCULATE_F5_SALT: 4055 case SM_SC_W2_CALCULATE_F5_MACKEY: 4056 case SM_SC_W4_CALCULATE_F5_MACKEY: 4057 case SM_SC_W2_CALCULATE_F5_LTK: 4058 case SM_SC_W4_CALCULATE_F5_LTK: 4059 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4060 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4061 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4062 case SM_SC_W4_USER_RESPONSE: 4063 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4064 sm_pdu_received_in_wrong_state(sm_conn); 4065 break; 4066 } 4067 // store DHKey Check 4068 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4069 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4070 4071 // have we been only waiting for dhkey check command? 4072 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4073 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4074 } 4075 break; 4076 #endif 4077 4078 #ifdef ENABLE_LE_PERIPHERAL 4079 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4080 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4081 sm_pdu_received_in_wrong_state(sm_conn); 4082 break; 4083 } 4084 4085 // received confirm value 4086 reverse_128(&packet[1], setup->sm_peer_confirm); 4087 4088 #ifdef ENABLE_TESTING_SUPPORT 4089 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4090 log_info("testing_support: reset confirm value"); 4091 memset(setup->sm_peer_confirm, 0, 16); 4092 } 4093 #endif 4094 // notify client to hide shown passkey 4095 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4096 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4097 } 4098 4099 // handle user cancel pairing? 4100 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4101 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4102 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4103 break; 4104 } 4105 4106 // wait for user action? 4107 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4108 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4109 break; 4110 } 4111 4112 // calculate and send local_confirm 4113 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); 4114 break; 4115 4116 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4117 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4118 sm_pdu_received_in_wrong_state(sm_conn); 4119 break;; 4120 } 4121 4122 // received random value 4123 reverse_128(&packet[1], setup->sm_peer_random); 4124 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4125 break; 4126 #endif 4127 4128 case SM_PH3_RECEIVE_KEYS: 4129 switch(sm_pdu_code){ 4130 case SM_CODE_ENCRYPTION_INFORMATION: 4131 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4132 reverse_128(&packet[1], setup->sm_peer_ltk); 4133 break; 4134 4135 case SM_CODE_MASTER_IDENTIFICATION: 4136 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4137 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4138 reverse_64(&packet[3], setup->sm_peer_rand); 4139 break; 4140 4141 case SM_CODE_IDENTITY_INFORMATION: 4142 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4143 reverse_128(&packet[1], setup->sm_peer_irk); 4144 break; 4145 4146 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4147 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4148 setup->sm_peer_addr_type = packet[1]; 4149 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4150 break; 4151 4152 case SM_CODE_SIGNING_INFORMATION: 4153 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4154 reverse_128(&packet[1], setup->sm_peer_csrk); 4155 break; 4156 default: 4157 // Unexpected PDU 4158 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4159 break; 4160 } 4161 // done with key distribution? 4162 if (sm_key_distribution_all_received(sm_conn)){ 4163 4164 sm_key_distribution_handle_all_received(sm_conn); 4165 4166 if (IS_RESPONDER(sm_conn->sm_role)){ 4167 if (sm_ctkd_from_le(sm_conn)){ 4168 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; 4169 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4170 } else { 4171 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4172 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 4173 sm_done_for_handle(sm_conn->sm_handle); 4174 } 4175 } else { 4176 if (setup->sm_use_secure_connections){ 4177 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4178 } else { 4179 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); 4180 } 4181 } 4182 } 4183 break; 4184 default: 4185 // Unexpected PDU 4186 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4187 break; 4188 } 4189 4190 // try to send next pdu 4191 sm_trigger_run(); 4192 } 4193 4194 // Security Manager Client API 4195 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4196 sm_get_oob_data = get_oob_data_callback; 4197 } 4198 4199 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)){ 4200 sm_get_sc_oob_data = get_sc_oob_data_callback; 4201 } 4202 4203 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4204 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4205 } 4206 4207 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4208 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4209 } 4210 4211 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4212 sm_min_encryption_key_size = min_size; 4213 sm_max_encryption_key_size = max_size; 4214 } 4215 4216 void sm_set_authentication_requirements(uint8_t auth_req){ 4217 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4218 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4219 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4220 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4221 } 4222 #endif 4223 sm_auth_req = auth_req; 4224 } 4225 4226 void sm_set_io_capabilities(io_capability_t io_capability){ 4227 sm_io_capabilities = io_capability; 4228 } 4229 4230 #ifdef ENABLE_LE_PERIPHERAL 4231 void sm_set_request_security(int enable){ 4232 sm_slave_request_security = enable; 4233 } 4234 #endif 4235 4236 void sm_set_er(sm_key_t er){ 4237 (void)memcpy(sm_persistent_er, er, 16); 4238 } 4239 4240 void sm_set_ir(sm_key_t ir){ 4241 (void)memcpy(sm_persistent_ir, ir, 16); 4242 } 4243 4244 // Testing support only 4245 void sm_test_set_irk(sm_key_t irk){ 4246 (void)memcpy(sm_persistent_irk, irk, 16); 4247 dkg_state = DKG_CALC_DHK; 4248 test_use_fixed_local_irk = true; 4249 } 4250 4251 void sm_test_use_fixed_local_csrk(void){ 4252 test_use_fixed_local_csrk = true; 4253 } 4254 4255 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4256 static void sm_ec_generated(void * arg){ 4257 UNUSED(arg); 4258 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4259 // trigger pairing if pending for ec key 4260 sm_trigger_run(); 4261 } 4262 static void sm_ec_generate_new_key(void){ 4263 log_info("sm: generate new ec key"); 4264 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4265 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4266 } 4267 #endif 4268 4269 #ifdef ENABLE_TESTING_SUPPORT 4270 void sm_test_set_pairing_failure(int reason){ 4271 test_pairing_failure = reason; 4272 } 4273 #endif 4274 4275 void sm_init(void){ 4276 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4277 sm_er_ir_set_default(); 4278 4279 // defaults 4280 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4281 | SM_STK_GENERATION_METHOD_OOB 4282 | SM_STK_GENERATION_METHOD_PASSKEY 4283 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4284 4285 sm_max_encryption_key_size = 16; 4286 sm_min_encryption_key_size = 7; 4287 4288 sm_fixed_passkey_in_display_role = 0xffffffff; 4289 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4290 4291 #ifdef USE_CMAC_ENGINE 4292 sm_cmac_active = 0; 4293 #endif 4294 dkg_state = DKG_W4_WORKING; 4295 rau_state = RAU_IDLE; 4296 sm_aes128_state = SM_AES128_IDLE; 4297 sm_address_resolution_test = -1; // no private address to resolve yet 4298 sm_address_resolution_ah_calculation_active = 0; 4299 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4300 sm_address_resolution_general_queue = NULL; 4301 4302 gap_random_adress_update_period = 15 * 60 * 1000L; 4303 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4304 4305 test_use_fixed_local_csrk = false; 4306 4307 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4308 4309 // register for HCI Events from HCI 4310 hci_event_callback_registration.callback = &sm_event_packet_handler; 4311 hci_add_event_handler(&hci_event_callback_registration); 4312 4313 // 4314 btstack_crypto_init(); 4315 4316 // init le_device_db 4317 le_device_db_init(); 4318 4319 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4320 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4321 4322 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4323 sm_ec_generate_new_key(); 4324 #endif 4325 } 4326 4327 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4328 sm_fixed_passkey_in_display_role = passkey; 4329 } 4330 4331 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4332 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4333 } 4334 4335 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4336 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4337 if (!hci_con) return NULL; 4338 return &hci_con->sm_connection; 4339 } 4340 4341 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4342 switch (sm_conn->sm_engine_state){ 4343 case SM_GENERAL_IDLE: 4344 case SM_RESPONDER_IDLE: 4345 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4346 sm_trigger_run(); 4347 break; 4348 default: 4349 break; 4350 } 4351 } 4352 4353 /** 4354 * @brief Trigger Security Request 4355 */ 4356 void sm_send_security_request(hci_con_handle_t con_handle){ 4357 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4358 if (!sm_conn) return; 4359 sm_send_security_request_for_connection(sm_conn); 4360 } 4361 4362 // request pairing 4363 void sm_request_pairing(hci_con_handle_t con_handle){ 4364 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4365 if (!sm_conn) return; // wrong connection 4366 4367 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4368 if (IS_RESPONDER(sm_conn->sm_role)){ 4369 sm_send_security_request_for_connection(sm_conn); 4370 } else { 4371 // used as a trigger to start central/master/initiator security procedures 4372 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4373 uint8_t ltk[16]; 4374 bool have_ltk; 4375 switch (sm_conn->sm_irk_lookup_state){ 4376 case IRK_LOOKUP_SUCCEEDED: 4377 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4378 have_ltk = !sm_is_null_key(ltk); 4379 log_info("have ltk %u", have_ltk); 4380 if (have_ltk){ 4381 sm_conn->sm_pairing_requested = 1; 4382 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4383 sm_reencryption_started(sm_conn); 4384 break; 4385 } 4386 /* fall through */ 4387 4388 case IRK_LOOKUP_FAILED: 4389 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4390 break; 4391 default: 4392 log_info("irk lookup pending"); 4393 sm_conn->sm_pairing_requested = 1; 4394 break; 4395 } 4396 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4397 sm_conn->sm_pairing_requested = 1; 4398 } 4399 } 4400 sm_trigger_run(); 4401 } 4402 4403 // called by client app on authorization request 4404 void sm_authorization_decline(hci_con_handle_t con_handle){ 4405 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4406 if (!sm_conn) return; // wrong connection 4407 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4408 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4409 } 4410 4411 void sm_authorization_grant(hci_con_handle_t con_handle){ 4412 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4413 if (!sm_conn) return; // wrong connection 4414 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4415 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4416 } 4417 4418 // GAP Bonding API 4419 4420 void sm_bonding_decline(hci_con_handle_t con_handle){ 4421 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4422 if (!sm_conn) return; // wrong connection 4423 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4424 log_info("decline, state %u", sm_conn->sm_engine_state); 4425 switch(sm_conn->sm_engine_state){ 4426 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4427 case SM_SC_W4_USER_RESPONSE: 4428 case SM_SC_W4_CONFIRMATION: 4429 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4430 #endif 4431 case SM_PH1_W4_USER_RESPONSE: 4432 switch (setup->sm_stk_generation_method){ 4433 case PK_RESP_INPUT: 4434 case PK_INIT_INPUT: 4435 case PK_BOTH_INPUT: 4436 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4437 break; 4438 case NUMERIC_COMPARISON: 4439 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4440 break; 4441 case JUST_WORKS: 4442 case OOB: 4443 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4444 break; 4445 default: 4446 btstack_assert(false); 4447 break; 4448 } 4449 break; 4450 default: 4451 break; 4452 } 4453 sm_trigger_run(); 4454 } 4455 4456 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4457 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4458 if (!sm_conn) return; // wrong connection 4459 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4460 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4461 if (setup->sm_use_secure_connections){ 4462 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4463 } else { 4464 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); 4465 } 4466 } 4467 4468 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4469 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4470 sm_sc_prepare_dhkey_check(sm_conn); 4471 } 4472 #endif 4473 4474 sm_trigger_run(); 4475 } 4476 4477 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4478 // for now, it's the same 4479 sm_just_works_confirm(con_handle); 4480 } 4481 4482 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4483 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4484 if (!sm_conn) return; // wrong connection 4485 sm_reset_tk(); 4486 big_endian_store_32(setup->sm_tk, 12, passkey); 4487 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4488 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4489 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); 4490 } 4491 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4492 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4493 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4494 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4495 sm_sc_start_calculating_local_confirm(sm_conn); 4496 } 4497 #endif 4498 sm_trigger_run(); 4499 } 4500 4501 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4502 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4503 if (!sm_conn) return; // wrong connection 4504 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4505 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4506 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4507 switch (action){ 4508 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4509 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4510 flags |= (1u << action); 4511 break; 4512 case SM_KEYPRESS_PASSKEY_CLEARED: 4513 // clear counter, keypress & erased flags + set passkey cleared 4514 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4515 break; 4516 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4517 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4518 // erase actions queued 4519 num_actions--; 4520 if (num_actions == 0u){ 4521 // clear counter, keypress & erased flags 4522 flags &= 0x19u; 4523 } 4524 break; 4525 } 4526 num_actions++; 4527 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4528 break; 4529 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4530 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4531 // enter actions queued 4532 num_actions--; 4533 if (num_actions == 0u){ 4534 // clear counter, keypress & erased flags 4535 flags &= 0x19u; 4536 } 4537 break; 4538 } 4539 num_actions++; 4540 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4541 break; 4542 default: 4543 break; 4544 } 4545 setup->sm_keypress_notification = (num_actions << 5) | flags; 4546 sm_trigger_run(); 4547 } 4548 4549 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4550 static void sm_handle_random_result_oob(void * arg){ 4551 UNUSED(arg); 4552 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4553 sm_trigger_run(); 4554 } 4555 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4556 4557 static btstack_crypto_random_t sm_crypto_random_oob_request; 4558 4559 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4560 sm_sc_oob_callback = callback; 4561 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4562 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4563 return 0; 4564 } 4565 #endif 4566 4567 /** 4568 * @brief Get Identity Resolving state 4569 * @param con_handle 4570 * @return irk_lookup_state_t 4571 */ 4572 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4573 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4574 if (!sm_conn) return IRK_LOOKUP_IDLE; 4575 return sm_conn->sm_irk_lookup_state; 4576 } 4577 4578 /** 4579 * @brief Identify device in LE Device DB 4580 * @param handle 4581 * @returns index from le_device_db or -1 if not found/identified 4582 */ 4583 int sm_le_device_index(hci_con_handle_t con_handle ){ 4584 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4585 if (!sm_conn) return -1; 4586 return sm_conn->sm_le_db_index; 4587 } 4588 4589 static int gap_random_address_type_requires_updates(void){ 4590 switch (gap_random_adress_type){ 4591 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4592 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4593 return 0; 4594 default: 4595 return 1; 4596 } 4597 } 4598 4599 static uint8_t own_address_type(void){ 4600 switch (gap_random_adress_type){ 4601 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4602 return BD_ADDR_TYPE_LE_PUBLIC; 4603 default: 4604 return BD_ADDR_TYPE_LE_RANDOM; 4605 } 4606 } 4607 4608 // GAP LE API 4609 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4610 gap_random_address_update_stop(); 4611 gap_random_adress_type = random_address_type; 4612 hci_le_set_own_address_type(own_address_type()); 4613 if (!gap_random_address_type_requires_updates()) return; 4614 gap_random_address_update_start(); 4615 gap_random_address_trigger(); 4616 } 4617 4618 gap_random_address_type_t gap_random_address_get_mode(void){ 4619 return gap_random_adress_type; 4620 } 4621 4622 void gap_random_address_set_update_period(int period_ms){ 4623 gap_random_adress_update_period = period_ms; 4624 if (!gap_random_address_type_requires_updates()) return; 4625 gap_random_address_update_stop(); 4626 gap_random_address_update_start(); 4627 } 4628 4629 void gap_random_address_set(const bd_addr_t addr){ 4630 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4631 (void)memcpy(sm_random_address, addr, 6); 4632 rau_state = RAU_SET_ADDRESS; 4633 sm_trigger_run(); 4634 } 4635 4636 #ifdef ENABLE_LE_PERIPHERAL 4637 /* 4638 * @brief Set Advertisement Paramters 4639 * @param adv_int_min 4640 * @param adv_int_max 4641 * @param adv_type 4642 * @param direct_address_type 4643 * @param direct_address 4644 * @param channel_map 4645 * @param filter_policy 4646 * 4647 * @note own_address_type is used from gap_random_address_set_mode 4648 */ 4649 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4650 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4651 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4652 direct_address_typ, direct_address, channel_map, filter_policy); 4653 } 4654 #endif 4655 4656 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4657 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4658 // wrong connection 4659 if (!sm_conn) return 0; 4660 // already encrypted 4661 if (sm_conn->sm_connection_encrypted) return 0; 4662 // only central can re-encrypt 4663 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4664 // irk status? 4665 switch(sm_conn->sm_irk_lookup_state){ 4666 case IRK_LOOKUP_FAILED: 4667 // done, cannot setup encryption 4668 return 0; 4669 case IRK_LOOKUP_SUCCEEDED: 4670 break; 4671 default: 4672 // IR Lookup pending 4673 return 1; 4674 } 4675 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4676 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4677 } 4678 4679 void sm_set_secure_connections_only_mode(bool enable){ 4680 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4681 sm_sc_only_mode = enable; 4682 #else 4683 // SC Only mode not possible without support for SC 4684 btstack_assert(enable == false); 4685 #endif 4686 } 4687 4688 const uint8_t * gap_get_persistent_irk(void){ 4689 return sm_persistent_irk; 4690 } 4691