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 sm_initialized; 184 185 static bool test_use_fixed_local_csrk; 186 static bool test_use_fixed_local_irk; 187 188 #ifdef ENABLE_TESTING_SUPPORT 189 static uint8_t test_pairing_failure; 190 #endif 191 192 // configuration 193 static uint8_t sm_accepted_stk_generation_methods; 194 static uint8_t sm_max_encryption_key_size; 195 static uint8_t sm_min_encryption_key_size; 196 static uint8_t sm_auth_req = 0; 197 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 198 static uint8_t sm_slave_request_security; 199 static uint32_t sm_fixed_passkey_in_display_role; 200 static bool sm_reconstruct_ltk_without_le_device_db_entry; 201 202 #ifdef ENABLE_LE_SECURE_CONNECTIONS 203 static bool sm_sc_only_mode; 204 static uint8_t sm_sc_oob_random[16]; 205 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 206 static sm_sc_oob_state_t sm_sc_oob_state; 207 #endif 208 209 210 static bool sm_persistent_keys_random_active; 211 static const btstack_tlv_t * sm_tlv_impl; 212 static void * sm_tlv_context; 213 214 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 215 static sm_key_t sm_persistent_er; 216 static sm_key_t sm_persistent_ir; 217 218 // derived from sm_persistent_ir 219 static sm_key_t sm_persistent_dhk; 220 static sm_key_t sm_persistent_irk; 221 static derived_key_generation_t dkg_state; 222 223 // derived from sm_persistent_er 224 // .. 225 226 // random address update 227 static random_address_update_t rau_state; 228 static bd_addr_t sm_random_address; 229 230 #ifdef USE_CMAC_ENGINE 231 // CMAC Calculation: General 232 static btstack_crypto_aes128_cmac_t sm_cmac_request; 233 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 234 static uint8_t sm_cmac_active; 235 static uint8_t sm_cmac_hash[16]; 236 #endif 237 238 // CMAC for ATT Signed Writes 239 #ifdef ENABLE_LE_SIGNED_WRITE 240 static uint16_t sm_cmac_signed_write_message_len; 241 static uint8_t sm_cmac_signed_write_header[3]; 242 static const uint8_t * sm_cmac_signed_write_message; 243 static uint8_t sm_cmac_signed_write_sign_counter[4]; 244 #endif 245 246 // CMAC for Secure Connection functions 247 #ifdef ENABLE_LE_SECURE_CONNECTIONS 248 static sm_connection_t * sm_cmac_connection; 249 static uint8_t sm_cmac_sc_buffer[80]; 250 #endif 251 252 // resolvable private address lookup / CSRK calculation 253 static int sm_address_resolution_test; 254 static int sm_address_resolution_ah_calculation_active; 255 static uint8_t sm_address_resolution_addr_type; 256 static bd_addr_t sm_address_resolution_address; 257 static void * sm_address_resolution_context; 258 static address_resolution_mode_t sm_address_resolution_mode; 259 static btstack_linked_list_t sm_address_resolution_general_queue; 260 261 // aes128 crypto engine. 262 static sm_aes128_state_t sm_aes128_state; 263 264 // crypto 265 static btstack_crypto_random_t sm_crypto_random_request; 266 static btstack_crypto_aes128_t sm_crypto_aes128_request; 267 #ifdef ENABLE_LE_SECURE_CONNECTIONS 268 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 269 #endif 270 271 // temp storage for random data 272 static uint8_t sm_random_data[8]; 273 static uint8_t sm_aes128_key[16]; 274 static uint8_t sm_aes128_plaintext[16]; 275 static uint8_t sm_aes128_ciphertext[16]; 276 277 // to receive hci events 278 static btstack_packet_callback_registration_t hci_event_callback_registration; 279 280 /* to dispatch sm event */ 281 static btstack_linked_list_t sm_event_handlers; 282 283 /* to schedule calls to sm_run */ 284 static btstack_timer_source_t sm_run_timer; 285 286 // LE Secure Connections 287 #ifdef ENABLE_LE_SECURE_CONNECTIONS 288 static ec_key_generation_state_t ec_key_generation_state; 289 static uint8_t ec_q[64]; 290 #endif 291 292 // 293 // Volume 3, Part H, Chapter 24 294 // "Security shall be initiated by the Security Manager in the device in the master role. 295 // The device in the slave role shall be the responding device." 296 // -> master := initiator, slave := responder 297 // 298 299 // data needed for security setup 300 typedef struct sm_setup_context { 301 302 btstack_timer_source_t sm_timeout; 303 304 // user response, (Phase 1 and/or 2) 305 uint8_t sm_user_response; 306 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 307 308 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 309 uint8_t sm_key_distribution_send_set; 310 uint8_t sm_key_distribution_sent_set; 311 uint8_t sm_key_distribution_received_set; 312 313 // Phase 2 (Pairing over SMP) 314 stk_generation_method_t sm_stk_generation_method; 315 sm_key_t sm_tk; 316 uint8_t sm_have_oob_data; 317 uint8_t sm_use_secure_connections; 318 319 sm_key_t sm_c1_t3_value; // c1 calculation 320 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 321 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 322 sm_key_t sm_local_random; 323 sm_key_t sm_local_confirm; 324 sm_key_t sm_peer_random; 325 sm_key_t sm_peer_confirm; 326 uint8_t sm_m_addr_type; // address and type can be removed 327 uint8_t sm_s_addr_type; // '' 328 bd_addr_t sm_m_address; // '' 329 bd_addr_t sm_s_address; // '' 330 sm_key_t sm_ltk; 331 332 uint8_t sm_state_vars; 333 #ifdef ENABLE_LE_SECURE_CONNECTIONS 334 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 335 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 336 sm_key_t sm_local_nonce; // might be combined with sm_local_random 337 uint8_t sm_dhkey[32]; 338 sm_key_t sm_peer_dhkey_check; 339 sm_key_t sm_local_dhkey_check; 340 sm_key_t sm_ra; 341 sm_key_t sm_rb; 342 sm_key_t sm_t; // used for f5 and h6 343 sm_key_t sm_mackey; 344 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 345 #endif 346 347 // Phase 3 348 349 // key distribution, we generate 350 uint16_t sm_local_y; 351 uint16_t sm_local_div; 352 uint16_t sm_local_ediv; 353 uint8_t sm_local_rand[8]; 354 sm_key_t sm_local_ltk; 355 sm_key_t sm_local_csrk; 356 sm_key_t sm_local_irk; 357 // sm_local_address/addr_type not needed 358 359 // key distribution, received from peer 360 uint16_t sm_peer_y; 361 uint16_t sm_peer_div; 362 uint16_t sm_peer_ediv; 363 uint8_t sm_peer_rand[8]; 364 sm_key_t sm_peer_ltk; 365 sm_key_t sm_peer_irk; 366 sm_key_t sm_peer_csrk; 367 uint8_t sm_peer_addr_type; 368 bd_addr_t sm_peer_address; 369 #ifdef ENABLE_LE_SIGNED_WRITE 370 int sm_le_device_index; 371 #endif 372 } sm_setup_context_t; 373 374 // 375 static sm_setup_context_t the_setup; 376 static sm_setup_context_t * setup = &the_setup; 377 378 // active connection - the one for which the_setup is used for 379 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 380 381 // @returns 1 if oob data is available 382 // stores oob data in provided 16 byte buffer if not null 383 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 384 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); 385 386 static void sm_run(void); 387 static void sm_done_for_handle(hci_con_handle_t con_handle); 388 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 389 static inline int sm_calc_actual_encryption_key_size(int other); 390 static int sm_validate_stk_generation_method(void); 391 static void sm_handle_encryption_result_address_resolution(void *arg); 392 static void sm_handle_encryption_result_dkg_dhk(void *arg); 393 static void sm_handle_encryption_result_dkg_irk(void *arg); 394 static void sm_handle_encryption_result_enc_a(void *arg); 395 static void sm_handle_encryption_result_enc_b(void *arg); 396 static void sm_handle_encryption_result_enc_c(void *arg); 397 static void sm_handle_encryption_result_enc_csrk(void *arg); 398 static void sm_handle_encryption_result_enc_d(void * arg); 399 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 400 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 401 #ifdef ENABLE_LE_PERIPHERAL 402 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 403 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 404 #endif 405 static void sm_handle_encryption_result_enc_stk(void *arg); 406 static void sm_handle_encryption_result_rau(void *arg); 407 static void sm_handle_random_result_ph2_tk(void * arg); 408 static void sm_handle_random_result_rau(void * arg); 409 #ifdef ENABLE_LE_SECURE_CONNECTIONS 410 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)); 411 static void sm_ec_generate_new_key(void); 412 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 413 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 414 static int sm_passkey_entry(stk_generation_method_t method); 415 #endif 416 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 417 418 static void log_info_hex16(const char * name, uint16_t value){ 419 log_info("%-6s 0x%04x", name, value); 420 } 421 422 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 423 // return packet[0]; 424 // } 425 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 426 return packet[1]; 427 } 428 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 429 return packet[2]; 430 } 431 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 432 return packet[3]; 433 } 434 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 435 return packet[4]; 436 } 437 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 438 return packet[5]; 439 } 440 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 441 return packet[6]; 442 } 443 444 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 445 packet[0] = code; 446 } 447 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 448 packet[1] = io_capability; 449 } 450 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 451 packet[2] = oob_data_flag; 452 } 453 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 454 packet[3] = auth_req; 455 } 456 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 457 packet[4] = max_encryption_key_size; 458 } 459 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 460 packet[5] = initiator_key_distribution; 461 } 462 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 463 packet[6] = responder_key_distribution; 464 } 465 466 // @returns 1 if all bytes are 0 467 static bool sm_is_null(uint8_t * data, int size){ 468 int i; 469 for (i=0; i < size ; i++){ 470 if (data[i] != 0) { 471 return false; 472 } 473 } 474 return true; 475 } 476 477 static bool sm_is_null_random(uint8_t random[8]){ 478 return sm_is_null(random, 8); 479 } 480 481 static bool sm_is_null_key(uint8_t * key){ 482 return sm_is_null(key, 16); 483 } 484 485 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 486 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 487 UNUSED(ts); 488 sm_run(); 489 } 490 static void sm_trigger_run(void){ 491 if (!sm_initialized) return; 492 (void)btstack_run_loop_remove_timer(&sm_run_timer); 493 btstack_run_loop_set_timer(&sm_run_timer, 0); 494 btstack_run_loop_add_timer(&sm_run_timer); 495 } 496 497 // Key utils 498 static void sm_reset_tk(void){ 499 int i; 500 for (i=0;i<16;i++){ 501 setup->sm_tk[i] = 0; 502 } 503 } 504 505 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 506 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 507 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 508 int i; 509 for (i = max_encryption_size ; i < 16 ; i++){ 510 key[15-i] = 0; 511 } 512 } 513 514 // ER / IR checks 515 static void sm_er_ir_set_default(void){ 516 int i; 517 for (i=0;i<16;i++){ 518 sm_persistent_er[i] = 0x30 + i; 519 sm_persistent_ir[i] = 0x90 + i; 520 } 521 } 522 523 static int sm_er_is_default(void){ 524 int i; 525 for (i=0;i<16;i++){ 526 if (sm_persistent_er[i] != (0x30+i)) return 0; 527 } 528 return 1; 529 } 530 531 static int sm_ir_is_default(void){ 532 int i; 533 for (i=0;i<16;i++){ 534 if (sm_persistent_ir[i] != (0x90+i)) return 0; 535 } 536 return 1; 537 } 538 539 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 540 UNUSED(channel); 541 542 // log event 543 hci_dump_packet(packet_type, 1, packet, size); 544 // dispatch to all event handlers 545 btstack_linked_list_iterator_t it; 546 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 547 while (btstack_linked_list_iterator_has_next(&it)){ 548 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 549 entry->callback(packet_type, 0, packet, size); 550 } 551 } 552 553 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){ 554 event[0] = type; 555 event[1] = event_size - 2; 556 little_endian_store_16(event, 2, con_handle); 557 event[4] = addr_type; 558 reverse_bd_addr(address, &event[5]); 559 } 560 561 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 562 uint8_t event[11]; 563 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 564 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 565 } 566 567 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){ 568 uint8_t event[15]; 569 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 570 little_endian_store_32(event, 11, passkey); 571 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 572 } 573 574 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){ 575 // fetch addr and addr type from db, only called for valid entries 576 bd_addr_t identity_address; 577 int identity_address_type; 578 le_device_db_info(index, &identity_address_type, identity_address, NULL); 579 580 uint8_t event[20]; 581 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 582 event[11] = identity_address_type; 583 reverse_bd_addr(identity_address, &event[12]); 584 little_endian_store_16(event, 18, index); 585 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 586 } 587 588 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){ 589 uint8_t event[12]; 590 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 591 event[11] = status; 592 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 593 } 594 595 596 static void sm_reencryption_started(sm_connection_t * sm_conn){ 597 598 if (sm_conn->sm_reencryption_active) return; 599 600 sm_conn->sm_reencryption_active = true; 601 602 int identity_addr_type; 603 bd_addr_t identity_addr; 604 if (sm_conn->sm_le_db_index >= 0){ 605 // fetch addr and addr type from db, only called for valid entries 606 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 607 } else { 608 // for legacy pairing with LTK re-construction, use current peer addr 609 identity_addr_type = sm_conn->sm_peer_addr_type; 610 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 611 } 612 613 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 614 } 615 616 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 617 618 if (!sm_conn->sm_reencryption_active) return; 619 620 sm_conn->sm_reencryption_active = false; 621 622 int identity_addr_type; 623 bd_addr_t identity_addr; 624 if (sm_conn->sm_le_db_index >= 0){ 625 // fetch addr and addr type from db, only called for valid entries 626 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 627 } else { 628 // for legacy pairing with LTK re-construction, use current peer addr 629 identity_addr_type = sm_conn->sm_peer_addr_type; 630 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 631 } 632 633 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 634 } 635 636 static void sm_pairing_started(sm_connection_t * sm_conn){ 637 638 if (sm_conn->sm_pairing_active) return; 639 640 sm_conn->sm_pairing_active = true; 641 642 uint8_t event[11]; 643 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 644 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 645 } 646 647 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 648 649 if (!sm_conn->sm_pairing_active) return; 650 651 sm_conn->sm_pairing_active = false; 652 653 uint8_t event[13]; 654 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 655 event[11] = status; 656 event[12] = reason; 657 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 658 } 659 660 // SMP Timeout implementation 661 662 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 663 // the Security Manager Timer shall be reset and started. 664 // 665 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 666 // 667 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 668 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 669 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 670 // established. 671 672 static void sm_timeout_handler(btstack_timer_source_t * timer){ 673 log_info("SM timeout"); 674 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 675 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 676 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 677 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 678 sm_done_for_handle(sm_conn->sm_handle); 679 680 // trigger handling of next ready connection 681 sm_run(); 682 } 683 static void sm_timeout_start(sm_connection_t * sm_conn){ 684 btstack_run_loop_remove_timer(&setup->sm_timeout); 685 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 686 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 687 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 688 btstack_run_loop_add_timer(&setup->sm_timeout); 689 } 690 static void sm_timeout_stop(void){ 691 btstack_run_loop_remove_timer(&setup->sm_timeout); 692 } 693 static void sm_timeout_reset(sm_connection_t * sm_conn){ 694 sm_timeout_stop(); 695 sm_timeout_start(sm_conn); 696 } 697 698 // end of sm timeout 699 700 // GAP Random Address updates 701 static gap_random_address_type_t gap_random_adress_type; 702 static btstack_timer_source_t gap_random_address_update_timer; 703 static uint32_t gap_random_adress_update_period; 704 705 static void gap_random_address_trigger(void){ 706 log_info("gap_random_address_trigger, state %u", rau_state); 707 if (rau_state != RAU_IDLE) return; 708 rau_state = RAU_GET_RANDOM; 709 sm_trigger_run(); 710 } 711 712 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 713 UNUSED(timer); 714 715 log_info("GAP Random Address Update due"); 716 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 717 btstack_run_loop_add_timer(&gap_random_address_update_timer); 718 gap_random_address_trigger(); 719 } 720 721 static void gap_random_address_update_start(void){ 722 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 723 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 724 btstack_run_loop_add_timer(&gap_random_address_update_timer); 725 } 726 727 static void gap_random_address_update_stop(void){ 728 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 729 } 730 731 // ah(k,r) helper 732 // r = padding || r 733 // r - 24 bit value 734 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 735 // r'= padding || r 736 memset(r_prime, 0, 16); 737 (void)memcpy(&r_prime[13], r, 3); 738 } 739 740 // d1 helper 741 // d' = padding || r || d 742 // d,r - 16 bit values 743 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 744 // d'= padding || r || d 745 memset(d1_prime, 0, 16); 746 big_endian_store_16(d1_prime, 12, r); 747 big_endian_store_16(d1_prime, 14, d); 748 } 749 750 // calculate arguments for first AES128 operation in C1 function 751 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){ 752 753 // p1 = pres || preq || rat’ || iat’ 754 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 755 // cant octet of pres becomes the most significant octet of p1. 756 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 757 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 758 // p1 is 0x05000800000302070710000001010001." 759 760 sm_key_t p1; 761 reverse_56(pres, &p1[0]); 762 reverse_56(preq, &p1[7]); 763 p1[14] = rat; 764 p1[15] = iat; 765 log_info_key("p1", p1); 766 log_info_key("r", r); 767 768 // t1 = r xor p1 769 int i; 770 for (i=0;i<16;i++){ 771 t1[i] = r[i] ^ p1[i]; 772 } 773 log_info_key("t1", t1); 774 } 775 776 // calculate arguments for second AES128 operation in C1 function 777 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 778 // p2 = padding || ia || ra 779 // "The least significant octet of ra becomes the least significant octet of p2 and 780 // the most significant octet of padding becomes the most significant octet of p2. 781 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 782 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 783 784 sm_key_t p2; 785 memset(p2, 0, 16); 786 (void)memcpy(&p2[4], ia, 6); 787 (void)memcpy(&p2[10], ra, 6); 788 log_info_key("p2", p2); 789 790 // c1 = e(k, t2_xor_p2) 791 int i; 792 for (i=0;i<16;i++){ 793 t3[i] = t2[i] ^ p2[i]; 794 } 795 log_info_key("t3", t3); 796 } 797 798 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 799 log_info_key("r1", r1); 800 log_info_key("r2", r2); 801 (void)memcpy(&r_prime[8], &r2[8], 8); 802 (void)memcpy(&r_prime[0], &r1[8], 8); 803 } 804 805 806 // decide on stk generation based on 807 // - pairing request 808 // - io capabilities 809 // - OOB data availability 810 static void sm_setup_tk(void){ 811 812 // horizontal: initiator capabilities 813 // vertial: responder capabilities 814 static const stk_generation_method_t stk_generation_method [5] [5] = { 815 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 816 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 817 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 818 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 819 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 820 }; 821 822 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 823 #ifdef ENABLE_LE_SECURE_CONNECTIONS 824 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 825 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 826 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 827 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 828 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 829 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 830 }; 831 #endif 832 833 // default: just works 834 setup->sm_stk_generation_method = JUST_WORKS; 835 836 #ifdef ENABLE_LE_SECURE_CONNECTIONS 837 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 838 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 839 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 840 #else 841 setup->sm_use_secure_connections = 0; 842 #endif 843 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 844 845 846 // decide if OOB will be used based on SC vs. Legacy and oob flags 847 bool use_oob; 848 if (setup->sm_use_secure_connections){ 849 // In LE Secure Connections pairing, the out of band method is used if at least 850 // one device has the peer device's out of band authentication data available. 851 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 852 } else { 853 // In LE legacy pairing, the out of band method is used if both the devices have 854 // the other device's out of band authentication data available. 855 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 856 } 857 if (use_oob){ 858 log_info("SM: have OOB data"); 859 log_info_key("OOB", setup->sm_tk); 860 setup->sm_stk_generation_method = OOB; 861 return; 862 } 863 864 // If both devices have not set the MITM option in the Authentication Requirements 865 // Flags, then the IO capabilities shall be ignored and the Just Works association 866 // model shall be used. 867 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 868 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 869 log_info("SM: MITM not required by both -> JUST WORKS"); 870 return; 871 } 872 873 // Reset TK as it has been setup in sm_init_setup 874 sm_reset_tk(); 875 876 // Also use just works if unknown io capabilites 877 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)){ 878 return; 879 } 880 881 // Otherwise the IO capabilities of the devices shall be used to determine the 882 // pairing method as defined in Table 2.4. 883 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 884 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 885 886 #ifdef ENABLE_LE_SECURE_CONNECTIONS 887 // table not define by default 888 if (setup->sm_use_secure_connections){ 889 generation_method = stk_generation_method_with_secure_connection; 890 } 891 #endif 892 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)]; 893 894 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 895 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); 896 } 897 898 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 899 int flags = 0; 900 if (key_set & SM_KEYDIST_ENC_KEY){ 901 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 902 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 903 } 904 if (key_set & SM_KEYDIST_ID_KEY){ 905 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 906 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 907 } 908 if (key_set & SM_KEYDIST_SIGN){ 909 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 910 } 911 return flags; 912 } 913 914 static void sm_setup_key_distribution(uint8_t key_set){ 915 setup->sm_key_distribution_received_set = 0; 916 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 917 setup->sm_key_distribution_sent_set = 0; 918 #ifdef ENABLE_LE_SIGNED_WRITE 919 setup->sm_le_device_index = -1; 920 #endif 921 } 922 923 // CSRK Key Lookup 924 925 926 static int sm_address_resolution_idle(void){ 927 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 928 } 929 930 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){ 931 (void)memcpy(sm_address_resolution_address, addr, 6); 932 sm_address_resolution_addr_type = addr_type; 933 sm_address_resolution_test = 0; 934 sm_address_resolution_mode = mode; 935 sm_address_resolution_context = context; 936 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 937 } 938 939 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 940 // check if already in list 941 btstack_linked_list_iterator_t it; 942 sm_lookup_entry_t * entry; 943 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 944 while(btstack_linked_list_iterator_has_next(&it)){ 945 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 946 if (entry->address_type != address_type) continue; 947 if (memcmp(entry->address, address, 6)) continue; 948 // already in list 949 return BTSTACK_BUSY; 950 } 951 entry = btstack_memory_sm_lookup_entry_get(); 952 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 953 entry->address_type = (bd_addr_type_t) address_type; 954 (void)memcpy(entry->address, address, 6); 955 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 956 sm_trigger_run(); 957 return 0; 958 } 959 960 // CMAC calculation using AES Engineq 961 #ifdef USE_CMAC_ENGINE 962 963 static void sm_cmac_done_trampoline(void * arg){ 964 UNUSED(arg); 965 sm_cmac_active = 0; 966 (*sm_cmac_done_callback)(sm_cmac_hash); 967 sm_trigger_run(); 968 } 969 970 int sm_cmac_ready(void){ 971 return sm_cmac_active == 0u; 972 } 973 #endif 974 975 #ifdef ENABLE_LE_SECURE_CONNECTIONS 976 // generic cmac calculation 977 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)){ 978 sm_cmac_active = 1; 979 sm_cmac_done_callback = done_callback; 980 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 981 } 982 #endif 983 984 // cmac for ATT Message signing 985 #ifdef ENABLE_LE_SIGNED_WRITE 986 987 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)){ 988 sm_cmac_active = 1; 989 sm_cmac_done_callback = done_callback; 990 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 991 } 992 993 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 994 if (offset >= sm_cmac_signed_write_message_len) { 995 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 996 return 0; 997 } 998 999 offset = sm_cmac_signed_write_message_len - 1 - offset; 1000 1001 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1002 if (offset < 3){ 1003 return sm_cmac_signed_write_header[offset]; 1004 } 1005 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1006 if (offset < actual_message_len_incl_header){ 1007 return sm_cmac_signed_write_message[offset - 3]; 1008 } 1009 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1010 } 1011 1012 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)){ 1013 // ATT Message Signing 1014 sm_cmac_signed_write_header[0] = opcode; 1015 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1016 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1017 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1018 sm_cmac_signed_write_message = message; 1019 sm_cmac_signed_write_message_len = total_message_len; 1020 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1021 } 1022 #endif 1023 1024 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1025 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1026 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1027 sm_conn->sm_pairing_active = true; 1028 switch (setup->sm_stk_generation_method){ 1029 case PK_RESP_INPUT: 1030 if (IS_RESPONDER(sm_conn->sm_role)){ 1031 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1032 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1033 } else { 1034 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)); 1035 } 1036 break; 1037 case PK_INIT_INPUT: 1038 if (IS_RESPONDER(sm_conn->sm_role)){ 1039 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)); 1040 } else { 1041 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1042 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1043 } 1044 break; 1045 case PK_BOTH_INPUT: 1046 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1047 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1048 break; 1049 case NUMERIC_COMPARISON: 1050 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1051 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)); 1052 break; 1053 case JUST_WORKS: 1054 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1055 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1056 break; 1057 case OOB: 1058 // client already provided OOB data, let's skip notification. 1059 break; 1060 default: 1061 btstack_assert(false); 1062 break; 1063 } 1064 } 1065 1066 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1067 int recv_flags; 1068 if (IS_RESPONDER(sm_conn->sm_role)){ 1069 // slave / responder 1070 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1071 } else { 1072 // master / initiator 1073 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1074 } 1075 1076 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1077 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1078 if (setup->sm_use_secure_connections){ 1079 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1080 } 1081 #endif 1082 1083 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1084 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1085 } 1086 1087 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1088 if (sm_active_connection_handle == con_handle){ 1089 sm_timeout_stop(); 1090 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1091 log_info("sm: connection 0x%x released setup context", con_handle); 1092 1093 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1094 // generate new ec key after each pairing (that used it) 1095 if (setup->sm_use_secure_connections){ 1096 sm_ec_generate_new_key(); 1097 } 1098 #endif 1099 } 1100 } 1101 1102 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1103 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1104 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1105 sm_done_for_handle(connection->sm_handle); 1106 } 1107 1108 static int sm_key_distribution_flags_for_auth_req(void){ 1109 1110 int flags = SM_KEYDIST_ID_KEY; 1111 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1112 // encryption and signing information only if bonding requested 1113 flags |= SM_KEYDIST_ENC_KEY; 1114 #ifdef ENABLE_LE_SIGNED_WRITE 1115 flags |= SM_KEYDIST_SIGN; 1116 #endif 1117 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1118 // LinkKey for CTKD requires SC 1119 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1120 flags |= SM_KEYDIST_LINK_KEY; 1121 } 1122 #endif 1123 } 1124 return flags; 1125 } 1126 1127 static void sm_reset_setup(void){ 1128 // fill in sm setup 1129 setup->sm_state_vars = 0; 1130 setup->sm_keypress_notification = 0; 1131 sm_reset_tk(); 1132 } 1133 1134 static void sm_init_setup(sm_connection_t * sm_conn){ 1135 1136 // fill in sm setup 1137 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1138 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1139 1140 // query client for Legacy Pairing OOB data 1141 setup->sm_have_oob_data = 0; 1142 if (sm_get_oob_data != NULL) { 1143 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1144 } 1145 1146 // if available and SC supported, also ask for SC OOB Data 1147 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1148 memset(setup->sm_ra, 0, 16); 1149 memset(setup->sm_rb, 0, 16); 1150 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1151 if (sm_get_sc_oob_data != NULL){ 1152 if (IS_RESPONDER(sm_conn->sm_role)){ 1153 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1154 sm_conn->sm_peer_addr_type, 1155 sm_conn->sm_peer_address, 1156 setup->sm_peer_confirm, 1157 setup->sm_ra); 1158 } else { 1159 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1160 sm_conn->sm_peer_addr_type, 1161 sm_conn->sm_peer_address, 1162 setup->sm_peer_confirm, 1163 setup->sm_rb); 1164 } 1165 } else { 1166 setup->sm_have_oob_data = 0; 1167 } 1168 } 1169 #endif 1170 1171 sm_pairing_packet_t * local_packet; 1172 if (IS_RESPONDER(sm_conn->sm_role)){ 1173 // slave 1174 local_packet = &setup->sm_s_pres; 1175 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1176 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1177 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1178 } else { 1179 // master 1180 local_packet = &setup->sm_m_preq; 1181 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1182 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1183 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1184 1185 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1186 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1187 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1188 } 1189 1190 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1191 uint8_t max_encryptinon_key_size = sm_max_encryption_key_size; 1192 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1193 // enable SC for SC only mode 1194 if (sm_sc_only_mode){ 1195 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1196 max_encryptinon_key_size = 16; 1197 } 1198 #endif 1199 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1200 // set CT2 if SC + Bonding + CTKD 1201 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1202 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1203 auth_req |= SM_AUTHREQ_CT2; 1204 } 1205 #endif 1206 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1207 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1208 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1209 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryptinon_key_size); 1210 } 1211 1212 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1213 1214 sm_pairing_packet_t * remote_packet; 1215 int remote_key_request; 1216 if (IS_RESPONDER(sm_conn->sm_role)){ 1217 // slave / responder 1218 remote_packet = &setup->sm_m_preq; 1219 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1220 } else { 1221 // master / initiator 1222 remote_packet = &setup->sm_s_pres; 1223 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1224 } 1225 1226 // check key size 1227 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1228 // SC Only mandates 128 bit key size 1229 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1230 return SM_REASON_ENCRYPTION_KEY_SIZE; 1231 } 1232 #endif 1233 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1234 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1235 1236 // decide on STK generation method / SC 1237 sm_setup_tk(); 1238 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1239 1240 // check if STK generation method is acceptable by client 1241 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1242 1243 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1244 // Check LE SC Only mode 1245 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1246 log_info("SC Only mode active but SC not possible"); 1247 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1248 } 1249 1250 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1251 if (setup->sm_use_secure_connections){ 1252 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1253 } 1254 #endif 1255 1256 // identical to responder 1257 sm_setup_key_distribution(remote_key_request); 1258 1259 // JUST WORKS doens't provide authentication 1260 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1261 1262 return 0; 1263 } 1264 1265 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1266 1267 // cache and reset context 1268 int matched_device_id = sm_address_resolution_test; 1269 address_resolution_mode_t mode = sm_address_resolution_mode; 1270 void * context = sm_address_resolution_context; 1271 1272 // reset context 1273 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1274 sm_address_resolution_context = NULL; 1275 sm_address_resolution_test = -1; 1276 hci_con_handle_t con_handle = 0; 1277 1278 sm_connection_t * sm_connection; 1279 sm_key_t ltk; 1280 bool have_ltk; 1281 #ifdef ENABLE_LE_CENTRAL 1282 bool trigger_pairing; 1283 #endif 1284 switch (mode){ 1285 case ADDRESS_RESOLUTION_GENERAL: 1286 break; 1287 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1288 sm_connection = (sm_connection_t *) context; 1289 con_handle = sm_connection->sm_handle; 1290 1291 // have ltk -> start encryption / send security request 1292 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1293 // "When a bond has been created between two devices, any reconnection should result in the local device 1294 // enabling or requesting encryption with the remote device before initiating any service request." 1295 1296 switch (event){ 1297 case ADDRESS_RESOLUTION_SUCCEEDED: 1298 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1299 sm_connection->sm_le_db_index = matched_device_id; 1300 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1301 1302 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1303 have_ltk = !sm_is_null_key(ltk); 1304 1305 if (sm_connection->sm_role) { 1306 #ifdef ENABLE_LE_PERIPHERAL 1307 // IRK required before, continue 1308 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1309 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1310 break; 1311 } 1312 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1313 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1314 break; 1315 } 1316 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1317 sm_connection->sm_pairing_requested = 0; 1318 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1319 // trigger security request for Proactive Authentication if LTK available 1320 trigger_security_request = trigger_security_request || have_ltk; 1321 #endif 1322 1323 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1324 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1325 1326 if (trigger_security_request){ 1327 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1328 if (have_ltk){ 1329 sm_reencryption_started(sm_connection); 1330 } else { 1331 sm_pairing_started(sm_connection); 1332 } 1333 sm_trigger_run(); 1334 } 1335 #endif 1336 } else { 1337 1338 #ifdef ENABLE_LE_CENTRAL 1339 // check if pairing already requested and reset requests 1340 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1341 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1342 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1343 sm_connection->sm_security_request_received = 0; 1344 sm_connection->sm_pairing_requested = 0; 1345 bool trigger_reencryption = false; 1346 1347 if (have_ltk){ 1348 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1349 trigger_reencryption = true; 1350 #else 1351 if (trigger_pairing){ 1352 trigger_reencryption = true; 1353 } else { 1354 log_info("central: defer enabling encryption for bonded device"); 1355 } 1356 #endif 1357 } 1358 1359 if (trigger_reencryption){ 1360 log_info("central: enable encryption for bonded device"); 1361 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1362 break; 1363 } 1364 1365 // pairing_request -> send pairing request 1366 if (trigger_pairing){ 1367 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1368 break; 1369 } 1370 #endif 1371 } 1372 break; 1373 case ADDRESS_RESOLUTION_FAILED: 1374 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1375 if (sm_connection->sm_role) { 1376 #ifdef ENABLE_LE_PERIPHERAL 1377 // LTK request received before, IRK required -> negative LTK reply 1378 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1379 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1380 } 1381 // send security request if requested 1382 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1383 sm_connection->sm_pairing_requested = 0; 1384 if (trigger_security_request){ 1385 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1386 sm_pairing_started(sm_connection); 1387 } 1388 break; 1389 #endif 1390 } 1391 #ifdef ENABLE_LE_CENTRAL 1392 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1393 sm_connection->sm_security_request_received = 0; 1394 sm_connection->sm_pairing_requested = 0; 1395 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1396 #endif 1397 break; 1398 1399 default: 1400 btstack_assert(false); 1401 break; 1402 } 1403 break; 1404 default: 1405 break; 1406 } 1407 1408 switch (event){ 1409 case ADDRESS_RESOLUTION_SUCCEEDED: 1410 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1411 break; 1412 case ADDRESS_RESOLUTION_FAILED: 1413 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1414 break; 1415 default: 1416 btstack_assert(false); 1417 break; 1418 } 1419 } 1420 1421 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1422 1423 int le_db_index = -1; 1424 1425 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1426 bool bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1427 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1428 & SM_AUTHREQ_BONDING ) != 0u; 1429 1430 if (bonding_enabed){ 1431 1432 // lookup device based on IRK 1433 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1434 int i; 1435 for (i=0; i < le_device_db_max_count(); i++){ 1436 sm_key_t irk; 1437 bd_addr_t address; 1438 int address_type = BD_ADDR_TYPE_UNKNOWN; 1439 le_device_db_info(i, &address_type, address, irk); 1440 // skip unused entries 1441 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1442 // compare IRK 1443 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1444 1445 log_info("sm: device found for IRK, updating"); 1446 le_db_index = i; 1447 break; 1448 } 1449 } else { 1450 // assert IRK is set to zero 1451 memset(setup->sm_peer_irk, 0, 16); 1452 } 1453 1454 // if not found, lookup via public address if possible 1455 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1456 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1457 int i; 1458 for (i=0; i < le_device_db_max_count(); i++){ 1459 bd_addr_t address; 1460 int address_type = BD_ADDR_TYPE_UNKNOWN; 1461 le_device_db_info(i, &address_type, address, NULL); 1462 // skip unused entries 1463 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1464 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1465 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1466 log_info("sm: device found for public address, updating"); 1467 le_db_index = i; 1468 break; 1469 } 1470 } 1471 } 1472 1473 // if not found, add to db 1474 bool new_to_le_device_db = false; 1475 if (le_db_index < 0) { 1476 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1477 new_to_le_device_db = true; 1478 } 1479 1480 if (le_db_index >= 0){ 1481 1482 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1483 if (!new_to_le_device_db){ 1484 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1485 } 1486 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1487 #else 1488 UNUSED(new_to_le_device_db); 1489 #endif 1490 1491 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1492 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1493 sm_conn->sm_le_db_index = le_db_index; 1494 1495 #ifdef ENABLE_LE_SIGNED_WRITE 1496 // store local CSRK 1497 setup->sm_le_device_index = le_db_index; 1498 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1499 log_info("sm: store local CSRK"); 1500 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1501 le_device_db_local_counter_set(le_db_index, 0); 1502 } 1503 1504 // store remote CSRK 1505 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1506 log_info("sm: store remote CSRK"); 1507 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1508 le_device_db_remote_counter_set(le_db_index, 0); 1509 } 1510 #endif 1511 // store encryption information for secure connections: LTK generated by ECDH 1512 if (setup->sm_use_secure_connections){ 1513 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1514 uint8_t zero_rand[8]; 1515 memset(zero_rand, 0, 8); 1516 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1517 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1518 } 1519 1520 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1521 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1522 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1523 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1524 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1525 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1526 1527 } 1528 } 1529 } else { 1530 log_info("Ignoring received keys, bonding not enabled"); 1531 } 1532 } 1533 1534 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1535 sm_conn->sm_pairing_failed_reason = reason; 1536 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1537 } 1538 1539 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1540 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1541 } 1542 1543 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1544 1545 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1546 static int sm_passkey_used(stk_generation_method_t method); 1547 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1548 1549 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1550 if (setup->sm_stk_generation_method == OOB){ 1551 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1552 } else { 1553 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); 1554 } 1555 } 1556 1557 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1558 if (IS_RESPONDER(sm_conn->sm_role)){ 1559 // Responder 1560 if (setup->sm_stk_generation_method == OOB){ 1561 // generate Nb 1562 log_info("Generate Nb"); 1563 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); 1564 } else { 1565 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1566 } 1567 } else { 1568 // Initiator role 1569 switch (setup->sm_stk_generation_method){ 1570 case JUST_WORKS: 1571 sm_sc_prepare_dhkey_check(sm_conn); 1572 break; 1573 1574 case NUMERIC_COMPARISON: 1575 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1576 break; 1577 case PK_INIT_INPUT: 1578 case PK_RESP_INPUT: 1579 case PK_BOTH_INPUT: 1580 if (setup->sm_passkey_bit < 20u) { 1581 sm_sc_start_calculating_local_confirm(sm_conn); 1582 } else { 1583 sm_sc_prepare_dhkey_check(sm_conn); 1584 } 1585 break; 1586 case OOB: 1587 sm_sc_prepare_dhkey_check(sm_conn); 1588 break; 1589 default: 1590 btstack_assert(false); 1591 break; 1592 } 1593 } 1594 } 1595 1596 static void sm_sc_cmac_done(uint8_t * hash){ 1597 log_info("sm_sc_cmac_done: "); 1598 log_info_hexdump(hash, 16); 1599 1600 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1601 sm_sc_oob_state = SM_SC_OOB_IDLE; 1602 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1603 return; 1604 } 1605 1606 sm_connection_t * sm_conn = sm_cmac_connection; 1607 sm_cmac_connection = NULL; 1608 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1609 link_key_type_t link_key_type; 1610 #endif 1611 1612 switch (sm_conn->sm_engine_state){ 1613 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1614 (void)memcpy(setup->sm_local_confirm, hash, 16); 1615 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1616 break; 1617 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1618 // check 1619 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1620 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1621 break; 1622 } 1623 sm_sc_state_after_receiving_random(sm_conn); 1624 break; 1625 case SM_SC_W4_CALCULATE_G2: { 1626 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1627 big_endian_store_32(setup->sm_tk, 12, vab); 1628 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1629 sm_trigger_user_response(sm_conn); 1630 break; 1631 } 1632 case SM_SC_W4_CALCULATE_F5_SALT: 1633 (void)memcpy(setup->sm_t, hash, 16); 1634 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1635 break; 1636 case SM_SC_W4_CALCULATE_F5_MACKEY: 1637 (void)memcpy(setup->sm_mackey, hash, 16); 1638 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1639 break; 1640 case SM_SC_W4_CALCULATE_F5_LTK: 1641 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1642 // Errata Service Release to the Bluetooth Specification: ESR09 1643 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1644 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1645 (void)memcpy(setup->sm_ltk, hash, 16); 1646 (void)memcpy(setup->sm_local_ltk, hash, 16); 1647 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1648 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1649 break; 1650 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1651 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1652 if (IS_RESPONDER(sm_conn->sm_role)){ 1653 // responder 1654 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1655 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1656 } else { 1657 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1658 } 1659 } else { 1660 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1661 } 1662 break; 1663 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1664 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1665 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1666 break; 1667 } 1668 if (IS_RESPONDER(sm_conn->sm_role)){ 1669 // responder 1670 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1671 } else { 1672 // initiator 1673 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1674 } 1675 break; 1676 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1677 case SM_SC_W4_CALCULATE_ILK: 1678 (void)memcpy(setup->sm_t, hash, 16); 1679 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1680 break; 1681 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1682 reverse_128(hash, setup->sm_t); 1683 link_key_type = sm_conn->sm_connection_authenticated ? 1684 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1685 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1686 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1687 if (IS_RESPONDER(sm_conn->sm_role)){ 1688 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1689 } else { 1690 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1691 } 1692 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1693 sm_done_for_handle(sm_conn->sm_handle); 1694 break; 1695 #endif 1696 default: 1697 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1698 break; 1699 } 1700 sm_trigger_run(); 1701 } 1702 1703 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){ 1704 const uint16_t message_len = 65; 1705 sm_cmac_connection = sm_conn; 1706 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1707 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1708 sm_cmac_sc_buffer[64] = z; 1709 log_info("f4 key"); 1710 log_info_hexdump(x, 16); 1711 log_info("f4 message"); 1712 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1713 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1714 } 1715 1716 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1717 static const uint8_t f5_length[] = { 0x01, 0x00}; 1718 1719 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1720 1721 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1722 1723 log_info("f5_calculate_salt"); 1724 // calculate salt for f5 1725 const uint16_t message_len = 32; 1726 sm_cmac_connection = sm_conn; 1727 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1728 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1729 } 1730 1731 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){ 1732 const uint16_t message_len = 53; 1733 sm_cmac_connection = sm_conn; 1734 1735 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1736 sm_cmac_sc_buffer[0] = 0; 1737 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1738 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1739 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1740 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1741 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1742 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1743 log_info("f5 key"); 1744 log_info_hexdump(t, 16); 1745 log_info("f5 message for MacKey"); 1746 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1747 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1748 } 1749 1750 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1751 sm_key56_t bd_addr_master, bd_addr_slave; 1752 bd_addr_master[0] = setup->sm_m_addr_type; 1753 bd_addr_slave[0] = setup->sm_s_addr_type; 1754 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1755 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1756 if (IS_RESPONDER(sm_conn->sm_role)){ 1757 // responder 1758 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1759 } else { 1760 // initiator 1761 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1762 } 1763 } 1764 1765 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1766 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1767 const uint16_t message_len = 53; 1768 sm_cmac_connection = sm_conn; 1769 sm_cmac_sc_buffer[0] = 1; 1770 // 1..52 setup before 1771 log_info("f5 key"); 1772 log_info_hexdump(t, 16); 1773 log_info("f5 message for LTK"); 1774 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1775 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1776 } 1777 1778 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1779 f5_ltk(sm_conn, setup->sm_t); 1780 } 1781 1782 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){ 1783 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1784 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1785 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1786 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1787 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1788 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1789 } 1790 1791 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1792 const uint16_t message_len = 65; 1793 sm_cmac_connection = sm_conn; 1794 log_info("f6 key"); 1795 log_info_hexdump(w, 16); 1796 log_info("f6 message"); 1797 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1798 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1799 } 1800 1801 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1802 // - U is 256 bits 1803 // - V is 256 bits 1804 // - X is 128 bits 1805 // - Y is 128 bits 1806 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){ 1807 const uint16_t message_len = 80; 1808 sm_cmac_connection = sm_conn; 1809 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1810 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1811 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1812 log_info("g2 key"); 1813 log_info_hexdump(x, 16); 1814 log_info("g2 message"); 1815 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1816 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1817 } 1818 1819 static void g2_calculate(sm_connection_t * sm_conn) { 1820 // calc Va if numeric comparison 1821 if (IS_RESPONDER(sm_conn->sm_role)){ 1822 // responder 1823 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1824 } else { 1825 // initiator 1826 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1827 } 1828 } 1829 1830 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1831 uint8_t z = 0; 1832 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1833 // some form of passkey 1834 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1835 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1836 setup->sm_passkey_bit++; 1837 } 1838 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1839 } 1840 1841 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1842 // OOB 1843 if (setup->sm_stk_generation_method == OOB){ 1844 if (IS_RESPONDER(sm_conn->sm_role)){ 1845 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1846 } else { 1847 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1848 } 1849 return; 1850 } 1851 1852 uint8_t z = 0; 1853 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1854 // some form of passkey 1855 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1856 // sm_passkey_bit was increased before sending confirm value 1857 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1858 } 1859 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1860 } 1861 1862 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1863 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1864 1865 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1866 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1867 return; 1868 } else { 1869 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1870 } 1871 } 1872 1873 static void sm_sc_dhkey_calculated(void * arg){ 1874 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1875 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1876 if (sm_conn == NULL) return; 1877 1878 log_info("dhkey"); 1879 log_info_hexdump(&setup->sm_dhkey[0], 32); 1880 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1881 // trigger next step 1882 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1883 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1884 } 1885 sm_trigger_run(); 1886 } 1887 1888 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1889 // calculate DHKCheck 1890 sm_key56_t bd_addr_master, bd_addr_slave; 1891 bd_addr_master[0] = setup->sm_m_addr_type; 1892 bd_addr_slave[0] = setup->sm_s_addr_type; 1893 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1894 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1895 uint8_t iocap_a[3]; 1896 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1897 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1898 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1899 uint8_t iocap_b[3]; 1900 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1901 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1902 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1903 if (IS_RESPONDER(sm_conn->sm_role)){ 1904 // responder 1905 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1906 f6_engine(sm_conn, setup->sm_mackey); 1907 } else { 1908 // initiator 1909 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1910 f6_engine(sm_conn, setup->sm_mackey); 1911 } 1912 } 1913 1914 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1915 // validate E = f6() 1916 sm_key56_t bd_addr_master, bd_addr_slave; 1917 bd_addr_master[0] = setup->sm_m_addr_type; 1918 bd_addr_slave[0] = setup->sm_s_addr_type; 1919 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1920 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1921 1922 uint8_t iocap_a[3]; 1923 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1924 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1925 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1926 uint8_t iocap_b[3]; 1927 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1928 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1929 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1930 if (IS_RESPONDER(sm_conn->sm_role)){ 1931 // responder 1932 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1933 f6_engine(sm_conn, setup->sm_mackey); 1934 } else { 1935 // initiator 1936 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1937 f6_engine(sm_conn, setup->sm_mackey); 1938 } 1939 } 1940 1941 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1942 1943 // 1944 // Link Key Conversion Function h6 1945 // 1946 // h6(W, keyID) = AES-CMAC_W(keyID) 1947 // - W is 128 bits 1948 // - keyID is 32 bits 1949 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1950 const uint16_t message_len = 4; 1951 sm_cmac_connection = sm_conn; 1952 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1953 log_info("h6 key"); 1954 log_info_hexdump(w, 16); 1955 log_info("h6 message"); 1956 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1957 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1958 } 1959 // 1960 // Link Key Conversion Function h7 1961 // 1962 // h7(SALT, W) = AES-CMAC_SALT(W) 1963 // - SALT is 128 bits 1964 // - W is 128 bits 1965 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1966 const uint16_t message_len = 16; 1967 sm_cmac_connection = sm_conn; 1968 log_info("h7 key"); 1969 log_info_hexdump(salt, 16); 1970 log_info("h7 message"); 1971 log_info_hexdump(w, 16); 1972 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1973 } 1974 1975 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1976 // Errata Service Release to the Bluetooth Specification: ESR09 1977 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1978 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1979 1980 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1981 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1982 } 1983 1984 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1985 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1986 } 1987 1988 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1989 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1990 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1991 } 1992 #endif 1993 1994 #endif 1995 1996 // key management legacy connections: 1997 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1998 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1999 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2000 // - responder reconnects: responder uses LTK receveived from master 2001 2002 // key management secure connections: 2003 // - both devices store same LTK from ECDH key exchange. 2004 2005 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2006 static void sm_load_security_info(sm_connection_t * sm_connection){ 2007 int encryption_key_size; 2008 int authenticated; 2009 int authorized; 2010 int secure_connection; 2011 2012 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2013 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2014 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2015 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); 2016 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2017 sm_connection->sm_connection_authenticated = authenticated; 2018 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2019 sm_connection->sm_connection_sc = secure_connection; 2020 } 2021 #endif 2022 2023 #ifdef ENABLE_LE_PERIPHERAL 2024 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2025 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2026 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2027 // re-establish used key encryption size 2028 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2029 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2030 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2031 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2032 // Legacy paring -> not SC 2033 sm_connection->sm_connection_sc = 0; 2034 log_info("sm: received ltk request with key size %u, authenticated %u", 2035 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2036 } 2037 #endif 2038 2039 // distributed key generation 2040 static bool sm_run_dpkg(void){ 2041 switch (dkg_state){ 2042 case DKG_CALC_IRK: 2043 // already busy? 2044 if (sm_aes128_state == SM_AES128_IDLE) { 2045 log_info("DKG_CALC_IRK started"); 2046 // IRK = d1(IR, 1, 0) 2047 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2048 sm_aes128_state = SM_AES128_ACTIVE; 2049 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2050 return true; 2051 } 2052 break; 2053 case DKG_CALC_DHK: 2054 // already busy? 2055 if (sm_aes128_state == SM_AES128_IDLE) { 2056 log_info("DKG_CALC_DHK started"); 2057 // DHK = d1(IR, 3, 0) 2058 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2059 sm_aes128_state = SM_AES128_ACTIVE; 2060 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2061 return true; 2062 } 2063 break; 2064 default: 2065 break; 2066 } 2067 return false; 2068 } 2069 2070 // random address updates 2071 static bool sm_run_rau(void){ 2072 switch (rau_state){ 2073 case RAU_GET_RANDOM: 2074 rau_state = RAU_W4_RANDOM; 2075 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2076 return true; 2077 case RAU_GET_ENC: 2078 // already busy? 2079 if (sm_aes128_state == SM_AES128_IDLE) { 2080 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2081 sm_aes128_state = SM_AES128_ACTIVE; 2082 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2083 return true; 2084 } 2085 break; 2086 case RAU_SET_ADDRESS: 2087 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2088 rau_state = RAU_IDLE; 2089 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2090 return true; 2091 default: 2092 break; 2093 } 2094 return false; 2095 } 2096 2097 // CSRK Lookup 2098 static bool sm_run_csrk(void){ 2099 btstack_linked_list_iterator_t it; 2100 2101 // -- if csrk lookup ready, find connection that require csrk lookup 2102 if (sm_address_resolution_idle()){ 2103 hci_connections_get_iterator(&it); 2104 while(btstack_linked_list_iterator_has_next(&it)){ 2105 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2106 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2107 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2108 // and start lookup 2109 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); 2110 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2111 break; 2112 } 2113 } 2114 } 2115 2116 // -- if csrk lookup ready, resolved addresses for received addresses 2117 if (sm_address_resolution_idle()) { 2118 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2119 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2120 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2121 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2122 btstack_memory_sm_lookup_entry_free(entry); 2123 } 2124 } 2125 2126 // -- Continue with CSRK device lookup by public or resolvable private address 2127 if (!sm_address_resolution_idle()){ 2128 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2129 while (sm_address_resolution_test < le_device_db_max_count()){ 2130 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2131 bd_addr_t addr; 2132 sm_key_t irk; 2133 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2134 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2135 2136 // skip unused entries 2137 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2138 sm_address_resolution_test++; 2139 continue; 2140 } 2141 2142 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2143 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2144 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2145 break; 2146 } 2147 2148 // if connection type is public, it must be a different one 2149 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2150 sm_address_resolution_test++; 2151 continue; 2152 } 2153 2154 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2155 2156 log_info("LE Device Lookup: calculate AH"); 2157 log_info_key("IRK", irk); 2158 2159 (void)memcpy(sm_aes128_key, irk, 16); 2160 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2161 sm_address_resolution_ah_calculation_active = 1; 2162 sm_aes128_state = SM_AES128_ACTIVE; 2163 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2164 return true; 2165 } 2166 2167 if (sm_address_resolution_test >= le_device_db_max_count()){ 2168 log_info("LE Device Lookup: not found"); 2169 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2170 } 2171 } 2172 return false; 2173 } 2174 2175 // SC OOB 2176 static bool sm_run_oob(void){ 2177 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2178 switch (sm_sc_oob_state){ 2179 case SM_SC_OOB_W2_CALC_CONFIRM: 2180 if (!sm_cmac_ready()) break; 2181 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2182 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2183 return true; 2184 default: 2185 break; 2186 } 2187 #endif 2188 return false; 2189 } 2190 2191 // handle basic actions that don't requires the full context 2192 static bool sm_run_basic(void){ 2193 btstack_linked_list_iterator_t it; 2194 hci_connections_get_iterator(&it); 2195 while(btstack_linked_list_iterator_has_next(&it)){ 2196 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2197 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2198 switch(sm_connection->sm_engine_state){ 2199 2200 // general 2201 case SM_GENERAL_SEND_PAIRING_FAILED: { 2202 uint8_t buffer[2]; 2203 buffer[0] = SM_CODE_PAIRING_FAILED; 2204 buffer[1] = sm_connection->sm_pairing_failed_reason; 2205 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2206 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2207 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2208 sm_done_for_handle(sm_connection->sm_handle); 2209 break; 2210 } 2211 2212 // responder side 2213 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2214 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2215 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2216 return true; 2217 2218 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2219 case SM_SC_RECEIVED_LTK_REQUEST: 2220 switch (sm_connection->sm_irk_lookup_state){ 2221 case IRK_LOOKUP_FAILED: 2222 log_info("LTK Request: IRK Lookup Failed)"); 2223 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2224 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2225 return true; 2226 default: 2227 break; 2228 } 2229 break; 2230 #endif 2231 default: 2232 break; 2233 } 2234 } 2235 return false; 2236 } 2237 2238 static void sm_run_activate_connection(void){ 2239 // Find connections that requires setup context and make active if no other is locked 2240 btstack_linked_list_iterator_t it; 2241 hci_connections_get_iterator(&it); 2242 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2243 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2244 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2245 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2246 bool done = true; 2247 int err; 2248 UNUSED(err); 2249 2250 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2251 // assert ec key is ready 2252 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2253 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2254 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2255 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2256 sm_ec_generate_new_key(); 2257 } 2258 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2259 continue; 2260 } 2261 } 2262 #endif 2263 2264 switch (sm_connection->sm_engine_state) { 2265 #ifdef ENABLE_LE_PERIPHERAL 2266 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2267 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2268 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2270 case SM_SC_RECEIVED_LTK_REQUEST: 2271 #endif 2272 #endif 2273 #ifdef ENABLE_LE_CENTRAL 2274 case SM_INITIATOR_PH4_HAS_LTK: 2275 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2276 #endif 2277 // just lock context 2278 break; 2279 default: 2280 done = false; 2281 break; 2282 } 2283 if (done){ 2284 sm_active_connection_handle = sm_connection->sm_handle; 2285 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); 2286 } 2287 } 2288 } 2289 2290 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2291 int i; 2292 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2293 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2294 uint8_t action = 0; 2295 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2296 if (flags & (1u<<i)){ 2297 bool clear_flag = true; 2298 switch (i){ 2299 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2300 case SM_KEYPRESS_PASSKEY_CLEARED: 2301 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2302 default: 2303 break; 2304 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2305 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2306 num_actions--; 2307 clear_flag = num_actions == 0u; 2308 break; 2309 } 2310 if (clear_flag){ 2311 flags &= ~(1<<i); 2312 } 2313 action = i; 2314 break; 2315 } 2316 } 2317 setup->sm_keypress_notification = (num_actions << 5) | flags; 2318 2319 // send keypress notification 2320 uint8_t buffer[2]; 2321 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2322 buffer[1] = action; 2323 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2324 2325 // try 2326 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2327 } 2328 2329 static void sm_run_distribute_keys(sm_connection_t * connection){ 2330 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2331 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2332 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2333 uint8_t buffer[17]; 2334 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2335 reverse_128(setup->sm_ltk, &buffer[1]); 2336 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2337 sm_timeout_reset(connection); 2338 return; 2339 } 2340 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2341 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2342 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2343 uint8_t buffer[11]; 2344 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2345 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2346 reverse_64(setup->sm_local_rand, &buffer[3]); 2347 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2348 sm_timeout_reset(connection); 2349 return; 2350 } 2351 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2352 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2353 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2354 uint8_t buffer[17]; 2355 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2356 reverse_128(sm_persistent_irk, &buffer[1]); 2357 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2358 sm_timeout_reset(connection); 2359 return; 2360 } 2361 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2362 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2363 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2364 bd_addr_t local_address; 2365 uint8_t buffer[8]; 2366 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2367 switch (gap_random_address_get_mode()){ 2368 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2369 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2370 // public or static random 2371 gap_le_get_own_address(&buffer[1], local_address); 2372 break; 2373 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2374 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2375 // fallback to public 2376 gap_local_bd_addr(local_address); 2377 buffer[1] = 0; 2378 break; 2379 default: 2380 btstack_assert(false); 2381 break; 2382 } 2383 reverse_bd_addr(local_address, &buffer[2]); 2384 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2385 sm_timeout_reset(connection); 2386 return; 2387 } 2388 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2389 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2390 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2391 2392 #ifdef ENABLE_LE_SIGNED_WRITE 2393 // hack to reproduce test runs 2394 if (test_use_fixed_local_csrk){ 2395 memset(setup->sm_local_csrk, 0xcc, 16); 2396 } 2397 2398 // store local CSRK 2399 if (setup->sm_le_device_index >= 0){ 2400 log_info("sm: store local CSRK"); 2401 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2402 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2403 } 2404 #endif 2405 2406 uint8_t buffer[17]; 2407 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2408 reverse_128(setup->sm_local_csrk, &buffer[1]); 2409 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2410 sm_timeout_reset(connection); 2411 return; 2412 } 2413 btstack_assert(false); 2414 } 2415 2416 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2417 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2418 // requirements to derive link key from LE: 2419 // - use secure connections 2420 if (setup->sm_use_secure_connections == 0) return false; 2421 // - bonding needs to be enabled: 2422 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; 2423 if (!bonding_enabled) return false; 2424 // - need identity address / public addr 2425 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2426 if (!have_identity_address_info) return false; 2427 // - 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) 2428 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2429 // If SC is authenticated, we consider it safe to overwrite a stored key. 2430 // 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. 2431 uint8_t link_key[16]; 2432 link_key_type_t link_key_type; 2433 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2434 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 2435 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2436 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2437 return false; 2438 } 2439 // get started (all of the above are true) 2440 return true; 2441 #else 2442 UNUSED(sm_connection); 2443 return false; 2444 #endif 2445 } 2446 2447 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2448 if (sm_ctkd_from_le(connection)){ 2449 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; 2450 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2451 } else { 2452 connection->sm_engine_state = SM_RESPONDER_IDLE; 2453 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2454 sm_done_for_handle(connection->sm_handle); 2455 } 2456 } 2457 2458 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2459 if (sm_ctkd_from_le(connection)){ 2460 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; 2461 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2462 } else { 2463 sm_master_pairing_success(connection); 2464 } 2465 } 2466 2467 static void sm_run(void){ 2468 2469 // assert that stack has already bootet 2470 if (hci_get_state() != HCI_STATE_WORKING) return; 2471 2472 // assert that we can send at least commands 2473 if (!hci_can_send_command_packet_now()) return; 2474 2475 // pause until IR/ER are ready 2476 if (sm_persistent_keys_random_active) return; 2477 2478 bool done; 2479 2480 // 2481 // non-connection related behaviour 2482 // 2483 2484 done = sm_run_dpkg(); 2485 if (done) return; 2486 2487 done = sm_run_rau(); 2488 if (done) return; 2489 2490 done = sm_run_csrk(); 2491 if (done) return; 2492 2493 done = sm_run_oob(); 2494 if (done) return; 2495 2496 // assert that we can send at least commands - cmd might have been sent by crypto engine 2497 if (!hci_can_send_command_packet_now()) return; 2498 2499 // handle basic actions that don't requires the full context 2500 done = sm_run_basic(); 2501 if (done) return; 2502 2503 // 2504 // active connection handling 2505 // -- use loop to handle next connection if lock on setup context is released 2506 2507 while (true) { 2508 2509 sm_run_activate_connection(); 2510 2511 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2512 2513 // 2514 // active connection handling 2515 // 2516 2517 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2518 if (!connection) { 2519 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2520 return; 2521 } 2522 2523 // assert that we could send a SM PDU - not needed for all of the following 2524 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2525 log_info("cannot send now, requesting can send now event"); 2526 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2527 return; 2528 } 2529 2530 // send keypress notifications 2531 if (setup->sm_keypress_notification){ 2532 sm_run_send_keypress_notification(connection); 2533 return; 2534 } 2535 2536 int key_distribution_flags; 2537 UNUSED(key_distribution_flags); 2538 int err; 2539 UNUSED(err); 2540 bool have_ltk; 2541 uint8_t ltk[16]; 2542 2543 log_info("sm_run: state %u", connection->sm_engine_state); 2544 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2545 log_info("sm_run // cannot send"); 2546 } 2547 switch (connection->sm_engine_state){ 2548 2549 // secure connections, initiator + responding states 2550 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2551 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2552 if (!sm_cmac_ready()) break; 2553 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2554 sm_sc_calculate_local_confirm(connection); 2555 break; 2556 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2557 if (!sm_cmac_ready()) break; 2558 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2559 sm_sc_calculate_remote_confirm(connection); 2560 break; 2561 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2562 if (!sm_cmac_ready()) break; 2563 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2564 sm_sc_calculate_f6_for_dhkey_check(connection); 2565 break; 2566 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2567 if (!sm_cmac_ready()) break; 2568 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2569 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2570 break; 2571 case SM_SC_W2_CALCULATE_F5_SALT: 2572 if (!sm_cmac_ready()) break; 2573 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2574 f5_calculate_salt(connection); 2575 break; 2576 case SM_SC_W2_CALCULATE_F5_MACKEY: 2577 if (!sm_cmac_ready()) break; 2578 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2579 f5_calculate_mackey(connection); 2580 break; 2581 case SM_SC_W2_CALCULATE_F5_LTK: 2582 if (!sm_cmac_ready()) break; 2583 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2584 f5_calculate_ltk(connection); 2585 break; 2586 case SM_SC_W2_CALCULATE_G2: 2587 if (!sm_cmac_ready()) break; 2588 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2589 g2_calculate(connection); 2590 break; 2591 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2592 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2593 if (!sm_cmac_ready()) break; 2594 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2595 h6_calculate_ilk(connection); 2596 break; 2597 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2598 if (!sm_cmac_ready()) break; 2599 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2600 h6_calculate_br_edr_link_key(connection); 2601 break; 2602 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2603 if (!sm_cmac_ready()) break; 2604 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2605 h7_calculate_ilk(connection); 2606 break; 2607 #endif 2608 #endif 2609 2610 #ifdef ENABLE_LE_CENTRAL 2611 // initiator side 2612 2613 case SM_INITIATOR_PH4_HAS_LTK: { 2614 sm_reset_setup(); 2615 sm_load_security_info(connection); 2616 sm_reencryption_started(connection); 2617 2618 sm_key_t peer_ltk_flipped; 2619 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2620 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2621 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2622 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2623 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2624 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2625 return; 2626 } 2627 2628 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2629 sm_reset_setup(); 2630 sm_init_setup(connection); 2631 sm_timeout_start(connection); 2632 sm_pairing_started(connection); 2633 2634 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2635 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2636 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2637 sm_timeout_reset(connection); 2638 break; 2639 #endif 2640 2641 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2642 2643 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2644 bool trigger_user_response = false; 2645 bool trigger_start_calculating_local_confirm = false; 2646 uint8_t buffer[65]; 2647 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2648 // 2649 reverse_256(&ec_q[0], &buffer[1]); 2650 reverse_256(&ec_q[32], &buffer[33]); 2651 2652 #ifdef ENABLE_TESTING_SUPPORT 2653 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2654 log_info("testing_support: invalidating public key"); 2655 // flip single bit of public key coordinate 2656 buffer[1] ^= 1; 2657 } 2658 #endif 2659 2660 // stk generation method 2661 // passkey entry: notify app to show passkey or to request passkey 2662 switch (setup->sm_stk_generation_method){ 2663 case JUST_WORKS: 2664 case NUMERIC_COMPARISON: 2665 if (IS_RESPONDER(connection->sm_role)){ 2666 // responder 2667 trigger_start_calculating_local_confirm = true; 2668 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2669 } else { 2670 // initiator 2671 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2672 } 2673 break; 2674 case PK_INIT_INPUT: 2675 case PK_RESP_INPUT: 2676 case PK_BOTH_INPUT: 2677 // use random TK for display 2678 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2679 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2680 setup->sm_passkey_bit = 0; 2681 2682 if (IS_RESPONDER(connection->sm_role)){ 2683 // responder 2684 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2685 } else { 2686 // initiator 2687 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2688 } 2689 trigger_user_response = true; 2690 break; 2691 case OOB: 2692 if (IS_RESPONDER(connection->sm_role)){ 2693 // responder 2694 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2695 } else { 2696 // initiator 2697 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2698 } 2699 break; 2700 default: 2701 btstack_assert(false); 2702 break; 2703 } 2704 2705 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2706 sm_timeout_reset(connection); 2707 2708 // trigger user response and calc confirm after sending pdu 2709 if (trigger_user_response){ 2710 sm_trigger_user_response(connection); 2711 } 2712 if (trigger_start_calculating_local_confirm){ 2713 sm_sc_start_calculating_local_confirm(connection); 2714 } 2715 break; 2716 } 2717 case SM_SC_SEND_CONFIRMATION: { 2718 uint8_t buffer[17]; 2719 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2720 reverse_128(setup->sm_local_confirm, &buffer[1]); 2721 if (IS_RESPONDER(connection->sm_role)){ 2722 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2723 } else { 2724 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2725 } 2726 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2727 sm_timeout_reset(connection); 2728 break; 2729 } 2730 case SM_SC_SEND_PAIRING_RANDOM: { 2731 uint8_t buffer[17]; 2732 buffer[0] = SM_CODE_PAIRING_RANDOM; 2733 reverse_128(setup->sm_local_nonce, &buffer[1]); 2734 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2735 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2736 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2737 if (IS_RESPONDER(connection->sm_role)){ 2738 // responder 2739 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2740 } else { 2741 // initiator 2742 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2743 } 2744 } else { 2745 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2746 if (IS_RESPONDER(connection->sm_role)){ 2747 // responder 2748 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2749 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2750 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2751 } else { 2752 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2753 sm_sc_prepare_dhkey_check(connection); 2754 } 2755 } else { 2756 // initiator 2757 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2758 } 2759 } 2760 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2761 sm_timeout_reset(connection); 2762 break; 2763 } 2764 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2765 uint8_t buffer[17]; 2766 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2767 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2768 2769 if (IS_RESPONDER(connection->sm_role)){ 2770 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2771 } else { 2772 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2773 } 2774 2775 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2776 sm_timeout_reset(connection); 2777 break; 2778 } 2779 2780 #endif 2781 2782 #ifdef ENABLE_LE_PERIPHERAL 2783 2784 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2785 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2786 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2787 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2788 sm_timeout_start(connection); 2789 break; 2790 } 2791 2792 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2793 case SM_SC_RECEIVED_LTK_REQUEST: 2794 switch (connection->sm_irk_lookup_state){ 2795 case IRK_LOOKUP_SUCCEEDED: 2796 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2797 // start using context by loading security info 2798 sm_reset_setup(); 2799 sm_load_security_info(connection); 2800 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2801 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2802 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2803 sm_reencryption_started(connection); 2804 sm_trigger_run(); 2805 break; 2806 } 2807 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2808 connection->sm_engine_state = SM_RESPONDER_IDLE; 2809 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2810 return; 2811 default: 2812 // just wait until IRK lookup is completed 2813 break; 2814 } 2815 break; 2816 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2817 2818 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2819 sm_reset_setup(); 2820 2821 // handle Pairing Request with LTK available 2822 switch (connection->sm_irk_lookup_state) { 2823 case IRK_LOOKUP_SUCCEEDED: 2824 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2825 have_ltk = !sm_is_null_key(ltk); 2826 if (have_ltk){ 2827 log_info("pairing request but LTK available"); 2828 // emit re-encryption start/fail sequence 2829 sm_reencryption_started(connection); 2830 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2831 } 2832 break; 2833 default: 2834 break; 2835 } 2836 2837 sm_init_setup(connection); 2838 sm_pairing_started(connection); 2839 2840 // recover pairing request 2841 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2842 err = sm_stk_generation_init(connection); 2843 2844 #ifdef ENABLE_TESTING_SUPPORT 2845 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2846 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2847 err = test_pairing_failure; 2848 } 2849 #endif 2850 if (err != 0){ 2851 sm_pairing_error(connection, err); 2852 sm_trigger_run(); 2853 break; 2854 } 2855 2856 sm_timeout_start(connection); 2857 2858 // generate random number first, if we need to show passkey, otherwise send response 2859 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2860 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2861 break; 2862 } 2863 2864 /* fall through */ 2865 2866 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2867 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2868 2869 // start with initiator key dist flags 2870 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2871 2872 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2873 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2874 if (setup->sm_use_secure_connections){ 2875 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2876 } 2877 #endif 2878 // setup in response 2879 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); 2880 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); 2881 2882 // update key distribution after ENC was dropped 2883 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2884 2885 if (setup->sm_use_secure_connections){ 2886 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2887 } else { 2888 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2889 } 2890 2891 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2892 sm_timeout_reset(connection); 2893 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2894 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2895 sm_trigger_user_response(connection); 2896 } 2897 return; 2898 #endif 2899 2900 case SM_PH2_SEND_PAIRING_RANDOM: { 2901 uint8_t buffer[17]; 2902 buffer[0] = SM_CODE_PAIRING_RANDOM; 2903 reverse_128(setup->sm_local_random, &buffer[1]); 2904 if (IS_RESPONDER(connection->sm_role)){ 2905 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2906 } else { 2907 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2908 } 2909 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2910 sm_timeout_reset(connection); 2911 break; 2912 } 2913 2914 case SM_PH2_C1_GET_ENC_A: 2915 // already busy? 2916 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2917 // calculate confirm using aes128 engine - step 1 2918 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); 2919 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2920 sm_aes128_state = SM_AES128_ACTIVE; 2921 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); 2922 break; 2923 2924 case SM_PH2_C1_GET_ENC_C: 2925 // already busy? 2926 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2927 // calculate m_confirm using aes128 engine - step 1 2928 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); 2929 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2930 sm_aes128_state = SM_AES128_ACTIVE; 2931 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); 2932 break; 2933 2934 case SM_PH2_CALC_STK: 2935 // already busy? 2936 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2937 // calculate STK 2938 if (IS_RESPONDER(connection->sm_role)){ 2939 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2940 } else { 2941 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2942 } 2943 connection->sm_engine_state = SM_PH2_W4_STK; 2944 sm_aes128_state = SM_AES128_ACTIVE; 2945 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); 2946 break; 2947 2948 case SM_PH3_Y_GET_ENC: 2949 // already busy? 2950 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2951 // PH3B2 - calculate Y from - enc 2952 2953 // dm helper (was sm_dm_r_prime) 2954 // r' = padding || r 2955 // r - 64 bit value 2956 memset(&sm_aes128_plaintext[0], 0, 8); 2957 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2958 2959 // Y = dm(DHK, Rand) 2960 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2961 sm_aes128_state = SM_AES128_ACTIVE; 2962 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); 2963 break; 2964 2965 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2966 uint8_t buffer[17]; 2967 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2968 reverse_128(setup->sm_local_confirm, &buffer[1]); 2969 if (IS_RESPONDER(connection->sm_role)){ 2970 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2971 } else { 2972 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2973 } 2974 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2975 sm_timeout_reset(connection); 2976 return; 2977 } 2978 #ifdef ENABLE_LE_PERIPHERAL 2979 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2980 sm_key_t stk_flipped; 2981 reverse_128(setup->sm_ltk, stk_flipped); 2982 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2983 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2984 return; 2985 } 2986 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2987 sm_key_t ltk_flipped; 2988 reverse_128(setup->sm_ltk, ltk_flipped); 2989 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2990 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2991 return; 2992 } 2993 2994 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2995 // already busy? 2996 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2997 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2998 2999 sm_reset_setup(); 3000 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3001 3002 sm_reencryption_started(connection); 3003 3004 // dm helper (was sm_dm_r_prime) 3005 // r' = padding || r 3006 // r - 64 bit value 3007 memset(&sm_aes128_plaintext[0], 0, 8); 3008 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3009 3010 // Y = dm(DHK, Rand) 3011 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3012 sm_aes128_state = SM_AES128_ACTIVE; 3013 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); 3014 return; 3015 #endif 3016 #ifdef ENABLE_LE_CENTRAL 3017 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3018 sm_key_t stk_flipped; 3019 reverse_128(setup->sm_ltk, stk_flipped); 3020 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3021 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3022 return; 3023 } 3024 #endif 3025 3026 case SM_PH3_DISTRIBUTE_KEYS: 3027 if (setup->sm_key_distribution_send_set != 0){ 3028 sm_run_distribute_keys(connection); 3029 return; 3030 } 3031 3032 // keys are sent 3033 if (IS_RESPONDER(connection->sm_role)){ 3034 // slave -> receive master keys if any 3035 if (sm_key_distribution_all_received(connection)){ 3036 sm_key_distribution_handle_all_received(connection); 3037 sm_key_distribution_complete_responder(connection); 3038 // start CTKD right away 3039 continue; 3040 } else { 3041 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3042 } 3043 } else { 3044 sm_master_pairing_success(connection); 3045 } 3046 break; 3047 3048 default: 3049 break; 3050 } 3051 3052 // check again if active connection was released 3053 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3054 } 3055 } 3056 3057 // sm_aes128_state stays active 3058 static void sm_handle_encryption_result_enc_a(void *arg){ 3059 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3060 sm_aes128_state = SM_AES128_IDLE; 3061 3062 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3063 if (connection == NULL) return; 3064 3065 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3066 sm_aes128_state = SM_AES128_ACTIVE; 3067 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); 3068 } 3069 3070 static void sm_handle_encryption_result_enc_b(void *arg){ 3071 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3072 sm_aes128_state = SM_AES128_IDLE; 3073 3074 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3075 if (connection == NULL) return; 3076 3077 log_info_key("c1!", setup->sm_local_confirm); 3078 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3079 sm_trigger_run(); 3080 } 3081 3082 // sm_aes128_state stays active 3083 static void sm_handle_encryption_result_enc_c(void *arg){ 3084 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3085 sm_aes128_state = SM_AES128_IDLE; 3086 3087 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3088 if (connection == NULL) return; 3089 3090 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3091 sm_aes128_state = SM_AES128_ACTIVE; 3092 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); 3093 } 3094 3095 static void sm_handle_encryption_result_enc_d(void * arg){ 3096 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3097 sm_aes128_state = SM_AES128_IDLE; 3098 3099 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3100 if (connection == NULL) return; 3101 3102 log_info_key("c1!", sm_aes128_ciphertext); 3103 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3104 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3105 sm_trigger_run(); 3106 return; 3107 } 3108 if (IS_RESPONDER(connection->sm_role)){ 3109 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3110 sm_trigger_run(); 3111 } else { 3112 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3113 sm_aes128_state = SM_AES128_ACTIVE; 3114 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); 3115 } 3116 } 3117 3118 static void sm_handle_encryption_result_enc_stk(void *arg){ 3119 sm_aes128_state = SM_AES128_IDLE; 3120 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3121 3122 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3123 if (connection == NULL) return; 3124 3125 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3126 log_info_key("stk", setup->sm_ltk); 3127 if (IS_RESPONDER(connection->sm_role)){ 3128 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3129 } else { 3130 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3131 } 3132 sm_trigger_run(); 3133 } 3134 3135 // sm_aes128_state stays active 3136 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3137 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3138 sm_aes128_state = SM_AES128_IDLE; 3139 3140 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3141 if (connection == NULL) return; 3142 3143 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3144 log_info_hex16("y", setup->sm_local_y); 3145 // PH3B3 - calculate EDIV 3146 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3147 log_info_hex16("ediv", setup->sm_local_ediv); 3148 // PH3B4 - calculate LTK - enc 3149 // LTK = d1(ER, DIV, 0)) 3150 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3151 sm_aes128_state = SM_AES128_ACTIVE; 3152 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); 3153 } 3154 3155 #ifdef ENABLE_LE_PERIPHERAL 3156 // sm_aes128_state stays active 3157 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3158 sm_aes128_state = SM_AES128_IDLE; 3159 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3160 3161 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3162 if (connection == NULL) return; 3163 3164 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3165 log_info_hex16("y", setup->sm_local_y); 3166 3167 // PH3B3 - calculate DIV 3168 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3169 log_info_hex16("ediv", setup->sm_local_ediv); 3170 // PH3B4 - calculate LTK - enc 3171 // LTK = d1(ER, DIV, 0)) 3172 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3173 sm_aes128_state = SM_AES128_ACTIVE; 3174 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); 3175 } 3176 #endif 3177 3178 // sm_aes128_state stays active 3179 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3180 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3181 sm_aes128_state = SM_AES128_IDLE; 3182 3183 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3184 if (connection == NULL) return; 3185 3186 log_info_key("ltk", setup->sm_ltk); 3187 // calc CSRK next 3188 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3189 sm_aes128_state = SM_AES128_ACTIVE; 3190 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); 3191 } 3192 3193 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3194 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3195 sm_aes128_state = SM_AES128_IDLE; 3196 3197 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3198 if (connection == NULL) return; 3199 3200 sm_aes128_state = SM_AES128_IDLE; 3201 log_info_key("csrk", setup->sm_local_csrk); 3202 if (setup->sm_key_distribution_send_set){ 3203 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3204 } else { 3205 // no keys to send, just continue 3206 if (IS_RESPONDER(connection->sm_role)){ 3207 if (sm_key_distribution_all_received(connection)){ 3208 sm_key_distribution_handle_all_received(connection); 3209 sm_key_distribution_complete_responder(connection); 3210 } else { 3211 // slave -> receive master keys 3212 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3213 } 3214 } else { 3215 sm_key_distribution_complete_initiator(connection); 3216 } 3217 } 3218 sm_trigger_run(); 3219 } 3220 3221 #ifdef ENABLE_LE_PERIPHERAL 3222 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3223 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3224 sm_aes128_state = SM_AES128_IDLE; 3225 3226 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3227 if (connection == NULL) return; 3228 3229 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3230 log_info_key("ltk", setup->sm_ltk); 3231 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3232 sm_trigger_run(); 3233 } 3234 #endif 3235 3236 static void sm_handle_encryption_result_address_resolution(void *arg){ 3237 UNUSED(arg); 3238 sm_aes128_state = SM_AES128_IDLE; 3239 3240 sm_address_resolution_ah_calculation_active = 0; 3241 // compare calulated address against connecting device 3242 uint8_t * hash = &sm_aes128_ciphertext[13]; 3243 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3244 log_info("LE Device Lookup: matched resolvable private address"); 3245 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3246 sm_trigger_run(); 3247 return; 3248 } 3249 // no match, try next 3250 sm_address_resolution_test++; 3251 sm_trigger_run(); 3252 } 3253 3254 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3255 UNUSED(arg); 3256 sm_aes128_state = SM_AES128_IDLE; 3257 3258 log_info_key("irk", sm_persistent_irk); 3259 dkg_state = DKG_CALC_DHK; 3260 sm_trigger_run(); 3261 } 3262 3263 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3264 UNUSED(arg); 3265 sm_aes128_state = SM_AES128_IDLE; 3266 3267 log_info_key("dhk", sm_persistent_dhk); 3268 dkg_state = DKG_READY; 3269 sm_trigger_run(); 3270 } 3271 3272 static void sm_handle_encryption_result_rau(void *arg){ 3273 UNUSED(arg); 3274 sm_aes128_state = SM_AES128_IDLE; 3275 3276 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3277 rau_state = RAU_SET_ADDRESS; 3278 sm_trigger_run(); 3279 } 3280 3281 static void sm_handle_random_result_rau(void * arg){ 3282 UNUSED(arg); 3283 // non-resolvable vs. resolvable 3284 switch (gap_random_adress_type){ 3285 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3286 // resolvable: use random as prand and calc address hash 3287 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3288 sm_random_address[0u] &= 0x3fu; 3289 sm_random_address[0u] |= 0x40u; 3290 rau_state = RAU_GET_ENC; 3291 break; 3292 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3293 default: 3294 // "The two most significant bits of the address shall be equal to ‘0’"" 3295 sm_random_address[0u] &= 0x3fu; 3296 rau_state = RAU_SET_ADDRESS; 3297 break; 3298 } 3299 sm_trigger_run(); 3300 } 3301 3302 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3303 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3304 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3305 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3306 if (connection == NULL) return; 3307 3308 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3309 sm_trigger_run(); 3310 } 3311 3312 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3313 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3314 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3315 if (connection == NULL) return; 3316 3317 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3318 sm_trigger_run(); 3319 } 3320 #endif 3321 3322 static void sm_handle_random_result_ph2_random(void * arg){ 3323 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3324 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3325 if (connection == NULL) return; 3326 3327 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3328 sm_trigger_run(); 3329 } 3330 3331 static void sm_handle_random_result_ph2_tk(void * arg){ 3332 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3333 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3334 if (connection == NULL) return; 3335 3336 sm_reset_tk(); 3337 uint32_t tk; 3338 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3339 // map random to 0-999999 without speding much cycles on a modulus operation 3340 tk = little_endian_read_32(sm_random_data,0); 3341 tk = tk & 0xfffff; // 1048575 3342 if (tk >= 999999u){ 3343 tk = tk - 999999u; 3344 } 3345 } else { 3346 // override with pre-defined passkey 3347 tk = sm_fixed_passkey_in_display_role; 3348 } 3349 big_endian_store_32(setup->sm_tk, 12, tk); 3350 if (IS_RESPONDER(connection->sm_role)){ 3351 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3352 } else { 3353 if (setup->sm_use_secure_connections){ 3354 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3355 } else { 3356 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3357 sm_trigger_user_response(connection); 3358 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3359 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3360 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); 3361 } 3362 } 3363 } 3364 sm_trigger_run(); 3365 } 3366 3367 static void sm_handle_random_result_ph3_div(void * arg){ 3368 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3369 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3370 if (connection == NULL) return; 3371 3372 // use 16 bit from random value as div 3373 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3374 log_info_hex16("div", setup->sm_local_div); 3375 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3376 sm_trigger_run(); 3377 } 3378 3379 static void sm_handle_random_result_ph3_random(void * arg){ 3380 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3381 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3382 if (connection == NULL) return; 3383 3384 reverse_64(sm_random_data, setup->sm_local_rand); 3385 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3386 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3387 // no db for authenticated flag hack: store flag in bit 4 of LSB 3388 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3389 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3390 } 3391 static void sm_validate_er_ir(void){ 3392 // warn about default ER/IR 3393 bool warning = false; 3394 if (sm_ir_is_default()){ 3395 warning = true; 3396 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3397 } 3398 if (sm_er_is_default()){ 3399 warning = true; 3400 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3401 } 3402 if (warning) { 3403 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3404 } 3405 } 3406 3407 static void sm_handle_random_result_ir(void *arg){ 3408 sm_persistent_keys_random_active = false; 3409 if (arg != NULL){ 3410 // key generated, store in tlv 3411 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3412 log_info("Generated IR key. Store in TLV status: %d", status); 3413 UNUSED(status); 3414 } 3415 log_info_key("IR", sm_persistent_ir); 3416 dkg_state = DKG_CALC_IRK; 3417 3418 if (test_use_fixed_local_irk){ 3419 log_info_key("IRK", sm_persistent_irk); 3420 dkg_state = DKG_CALC_DHK; 3421 } 3422 3423 sm_trigger_run(); 3424 } 3425 3426 static void sm_handle_random_result_er(void *arg){ 3427 sm_persistent_keys_random_active = false; 3428 if (arg != 0){ 3429 // key generated, store in tlv 3430 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3431 log_info("Generated ER key. Store in TLV status: %d", status); 3432 UNUSED(status); 3433 } 3434 log_info_key("ER", sm_persistent_er); 3435 3436 // try load ir 3437 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3438 if (key_size == 16){ 3439 // ok, let's continue 3440 log_info("IR from TLV"); 3441 sm_handle_random_result_ir( NULL ); 3442 } else { 3443 // invalid, generate new random one 3444 sm_persistent_keys_random_active = true; 3445 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3446 } 3447 } 3448 3449 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3450 3451 UNUSED(channel); // ok: there is no channel 3452 UNUSED(size); // ok: fixed format HCI events 3453 3454 sm_connection_t * sm_conn; 3455 hci_con_handle_t con_handle; 3456 uint8_t status; 3457 switch (packet_type) { 3458 3459 case HCI_EVENT_PACKET: 3460 switch (hci_event_packet_get_type(packet)) { 3461 3462 case BTSTACK_EVENT_STATE: 3463 // bt stack activated, get started 3464 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3465 log_info("HCI Working!"); 3466 3467 // setup IR/ER with TLV 3468 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3469 if (sm_tlv_impl != NULL){ 3470 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3471 if (key_size == 16){ 3472 // ok, let's continue 3473 log_info("ER from TLV"); 3474 sm_handle_random_result_er( NULL ); 3475 } else { 3476 // invalid, generate random one 3477 sm_persistent_keys_random_active = true; 3478 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3479 } 3480 } else { 3481 sm_validate_er_ir(); 3482 dkg_state = DKG_CALC_IRK; 3483 3484 if (test_use_fixed_local_irk){ 3485 log_info_key("IRK", sm_persistent_irk); 3486 dkg_state = DKG_CALC_DHK; 3487 } 3488 } 3489 3490 // restart random address updates after power cycle 3491 gap_random_address_set_mode(gap_random_adress_type); 3492 } 3493 break; 3494 3495 case HCI_EVENT_LE_META: 3496 switch (packet[2]) { 3497 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3498 3499 log_info("sm: connected"); 3500 3501 if (packet[3]) return; // connection failed 3502 3503 con_handle = little_endian_read_16(packet, 4); 3504 sm_conn = sm_get_connection_for_handle(con_handle); 3505 if (!sm_conn) break; 3506 3507 sm_conn->sm_handle = con_handle; 3508 sm_conn->sm_role = packet[6]; 3509 sm_conn->sm_peer_addr_type = packet[7]; 3510 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3511 3512 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3513 3514 // reset security properties 3515 sm_conn->sm_connection_encrypted = 0; 3516 sm_conn->sm_connection_authenticated = 0; 3517 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3518 sm_conn->sm_le_db_index = -1; 3519 sm_conn->sm_reencryption_active = false; 3520 3521 // prepare CSRK lookup (does not involve setup) 3522 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3523 3524 // just connected -> everything else happens in sm_run() 3525 if (IS_RESPONDER(sm_conn->sm_role)){ 3526 // peripheral 3527 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3528 break; 3529 } else { 3530 // master 3531 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3532 } 3533 break; 3534 3535 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3536 con_handle = little_endian_read_16(packet, 3); 3537 sm_conn = sm_get_connection_for_handle(con_handle); 3538 if (!sm_conn) break; 3539 3540 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3541 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3542 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3543 break; 3544 } 3545 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3546 // PH2 SEND LTK as we need to exchange keys in PH3 3547 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3548 break; 3549 } 3550 3551 // store rand and ediv 3552 reverse_64(&packet[5], sm_conn->sm_local_rand); 3553 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3554 3555 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3556 // potentially stored LTK is from the master 3557 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3558 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3559 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3560 break; 3561 } 3562 // additionally check if remote is in LE Device DB if requested 3563 switch(sm_conn->sm_irk_lookup_state){ 3564 case IRK_LOOKUP_FAILED: 3565 log_info("LTK Request: device not in device db"); 3566 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3567 break; 3568 case IRK_LOOKUP_SUCCEEDED: 3569 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3570 break; 3571 default: 3572 // wait for irk look doen 3573 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3574 break; 3575 } 3576 break; 3577 } 3578 3579 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3580 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3581 #else 3582 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3583 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3584 #endif 3585 break; 3586 3587 default: 3588 break; 3589 } 3590 break; 3591 3592 case HCI_EVENT_ENCRYPTION_CHANGE: 3593 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3594 sm_conn = sm_get_connection_for_handle(con_handle); 3595 if (!sm_conn) break; 3596 3597 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3598 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3599 sm_conn->sm_actual_encryption_key_size); 3600 log_info("event handler, state %u", sm_conn->sm_engine_state); 3601 3602 switch (sm_conn->sm_engine_state){ 3603 3604 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3605 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3606 if (sm_conn->sm_connection_encrypted) { 3607 status = ERROR_CODE_SUCCESS; 3608 if (sm_conn->sm_role){ 3609 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3610 } else { 3611 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3612 } 3613 } else { 3614 status = hci_event_encryption_change_get_status(packet); 3615 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3616 // also, gap_reconnect_security_setup_active will return true 3617 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3618 } 3619 3620 // emit re-encryption complete 3621 sm_reencryption_complete(sm_conn, status); 3622 3623 // notify client, if pairing was requested before 3624 if (sm_conn->sm_pairing_requested){ 3625 sm_conn->sm_pairing_requested = 0; 3626 sm_pairing_complete(sm_conn, status, 0); 3627 } 3628 3629 sm_done_for_handle(sm_conn->sm_handle); 3630 break; 3631 3632 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3633 if (!sm_conn->sm_connection_encrypted) break; 3634 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3635 if (IS_RESPONDER(sm_conn->sm_role)){ 3636 // slave 3637 if (setup->sm_use_secure_connections){ 3638 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3639 } else { 3640 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); 3641 } 3642 } else { 3643 // master 3644 if (sm_key_distribution_all_received(sm_conn)){ 3645 // skip receiving keys as there are none 3646 sm_key_distribution_handle_all_received(sm_conn); 3647 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); 3648 } else { 3649 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3650 } 3651 } 3652 break; 3653 default: 3654 break; 3655 } 3656 break; 3657 3658 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3659 con_handle = little_endian_read_16(packet, 3); 3660 sm_conn = sm_get_connection_for_handle(con_handle); 3661 if (!sm_conn) break; 3662 3663 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3664 log_info("event handler, state %u", sm_conn->sm_engine_state); 3665 // continue if part of initial pairing 3666 switch (sm_conn->sm_engine_state){ 3667 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3668 if (sm_conn->sm_role){ 3669 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3670 } else { 3671 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3672 } 3673 sm_done_for_handle(sm_conn->sm_handle); 3674 break; 3675 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3676 if (IS_RESPONDER(sm_conn->sm_role)){ 3677 // slave 3678 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); 3679 } else { 3680 // master 3681 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3682 } 3683 break; 3684 default: 3685 break; 3686 } 3687 break; 3688 3689 3690 case HCI_EVENT_DISCONNECTION_COMPLETE: 3691 con_handle = little_endian_read_16(packet, 3); 3692 sm_done_for_handle(con_handle); 3693 sm_conn = sm_get_connection_for_handle(con_handle); 3694 if (!sm_conn) break; 3695 3696 // pairing failed, if it was ongoing 3697 switch (sm_conn->sm_engine_state){ 3698 case SM_GENERAL_IDLE: 3699 case SM_INITIATOR_CONNECTED: 3700 case SM_RESPONDER_IDLE: 3701 break; 3702 default: 3703 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 3704 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3705 break; 3706 } 3707 3708 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3709 sm_conn->sm_handle = 0; 3710 break; 3711 3712 case HCI_EVENT_COMMAND_COMPLETE: 3713 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3714 // set local addr for le device db 3715 bd_addr_t addr; 3716 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3717 le_device_db_set_local_bd_addr(addr); 3718 } 3719 break; 3720 default: 3721 break; 3722 } 3723 break; 3724 default: 3725 break; 3726 } 3727 3728 sm_run(); 3729 } 3730 3731 static inline int sm_calc_actual_encryption_key_size(int other){ 3732 if (other < sm_min_encryption_key_size) return 0; 3733 if (other < sm_max_encryption_key_size) return other; 3734 return sm_max_encryption_key_size; 3735 } 3736 3737 3738 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3739 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3740 switch (method){ 3741 case JUST_WORKS: 3742 case NUMERIC_COMPARISON: 3743 return 1; 3744 default: 3745 return 0; 3746 } 3747 } 3748 // responder 3749 3750 static int sm_passkey_used(stk_generation_method_t method){ 3751 switch (method){ 3752 case PK_RESP_INPUT: 3753 return 1; 3754 default: 3755 return 0; 3756 } 3757 } 3758 3759 static int sm_passkey_entry(stk_generation_method_t method){ 3760 switch (method){ 3761 case PK_RESP_INPUT: 3762 case PK_INIT_INPUT: 3763 case PK_BOTH_INPUT: 3764 return 1; 3765 default: 3766 return 0; 3767 } 3768 } 3769 3770 #endif 3771 3772 /** 3773 * @return ok 3774 */ 3775 static int sm_validate_stk_generation_method(void){ 3776 // check if STK generation method is acceptable by client 3777 switch (setup->sm_stk_generation_method){ 3778 case JUST_WORKS: 3779 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3780 case PK_RESP_INPUT: 3781 case PK_INIT_INPUT: 3782 case PK_BOTH_INPUT: 3783 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3784 case OOB: 3785 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3786 case NUMERIC_COMPARISON: 3787 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3788 default: 3789 return 0; 3790 } 3791 } 3792 3793 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3794 3795 // size of complete sm_pdu used to validate input 3796 static const uint8_t sm_pdu_size[] = { 3797 0, // 0x00 invalid opcode 3798 7, // 0x01 pairing request 3799 7, // 0x02 pairing response 3800 17, // 0x03 pairing confirm 3801 17, // 0x04 pairing random 3802 2, // 0x05 pairing failed 3803 17, // 0x06 encryption information 3804 11, // 0x07 master identification 3805 17, // 0x08 identification information 3806 8, // 0x09 identify address information 3807 17, // 0x0a signing information 3808 2, // 0x0b security request 3809 65, // 0x0c pairing public key 3810 17, // 0x0d pairing dhk check 3811 2, // 0x0e keypress notification 3812 }; 3813 3814 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3815 sm_run(); 3816 } 3817 3818 if (packet_type != SM_DATA_PACKET) return; 3819 if (size == 0u) return; 3820 3821 uint8_t sm_pdu_code = packet[0]; 3822 3823 // validate pdu size 3824 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3825 if (sm_pdu_size[sm_pdu_code] != size) return; 3826 3827 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3828 if (!sm_conn) return; 3829 3830 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3831 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 3832 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3833 sm_done_for_handle(con_handle); 3834 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3835 return; 3836 } 3837 3838 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3839 3840 int err; 3841 UNUSED(err); 3842 3843 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3844 uint8_t buffer[5]; 3845 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3846 buffer[1] = 3; 3847 little_endian_store_16(buffer, 2, con_handle); 3848 buffer[4] = packet[1]; 3849 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3850 return; 3851 } 3852 3853 #ifdef ENABLE_LE_CENTRAL 3854 int have_ltk; 3855 uint8_t ltk[16]; 3856 #endif 3857 3858 switch (sm_conn->sm_engine_state){ 3859 3860 // a sm timeout requires a new physical connection 3861 case SM_GENERAL_TIMEOUT: 3862 return; 3863 3864 #ifdef ENABLE_LE_CENTRAL 3865 3866 // Initiator 3867 case SM_INITIATOR_CONNECTED: 3868 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3869 sm_pdu_received_in_wrong_state(sm_conn); 3870 break; 3871 } 3872 3873 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3874 if (sm_sc_only_mode){ 3875 uint8_t auth_req = packet[1]; 3876 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 3877 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 3878 break; 3879 } 3880 } 3881 #endif 3882 3883 // IRK complete? 3884 switch (sm_conn->sm_irk_lookup_state){ 3885 case IRK_LOOKUP_FAILED: 3886 // start pairing 3887 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3888 break; 3889 case IRK_LOOKUP_SUCCEEDED: 3890 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3891 have_ltk = !sm_is_null_key(ltk); 3892 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 3893 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 3894 // start re-encrypt if we have LTK and the connection is not already encrypted 3895 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 3896 } else { 3897 // start pairing 3898 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3899 } 3900 break; 3901 default: 3902 // otherwise, store security request 3903 sm_conn->sm_security_request_received = 1; 3904 break; 3905 } 3906 break; 3907 3908 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3909 // Core 5, Vol 3, Part H, 2.4.6: 3910 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3911 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3912 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3913 log_info("Ignoring Security Request"); 3914 break; 3915 } 3916 3917 // all other pdus are incorrect 3918 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3919 sm_pdu_received_in_wrong_state(sm_conn); 3920 break; 3921 } 3922 3923 // store pairing request 3924 (void)memcpy(&setup->sm_s_pres, packet, 3925 sizeof(sm_pairing_packet_t)); 3926 err = sm_stk_generation_init(sm_conn); 3927 3928 #ifdef ENABLE_TESTING_SUPPORT 3929 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3930 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3931 err = test_pairing_failure; 3932 } 3933 #endif 3934 3935 if (err != 0){ 3936 sm_pairing_error(sm_conn, err); 3937 break; 3938 } 3939 3940 // generate random number first, if we need to show passkey 3941 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3942 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); 3943 break; 3944 } 3945 3946 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3947 if (setup->sm_use_secure_connections){ 3948 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3949 if (setup->sm_stk_generation_method == JUST_WORKS){ 3950 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3951 sm_trigger_user_response(sm_conn); 3952 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3953 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3954 } 3955 } else { 3956 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3957 } 3958 break; 3959 } 3960 #endif 3961 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3962 sm_trigger_user_response(sm_conn); 3963 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3964 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3965 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); 3966 } 3967 break; 3968 3969 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3970 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3971 sm_pdu_received_in_wrong_state(sm_conn); 3972 break; 3973 } 3974 3975 // store s_confirm 3976 reverse_128(&packet[1], setup->sm_peer_confirm); 3977 3978 // abort if s_confirm matches m_confirm 3979 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 3980 sm_pdu_received_in_wrong_state(sm_conn); 3981 break; 3982 } 3983 3984 #ifdef ENABLE_TESTING_SUPPORT 3985 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3986 log_info("testing_support: reset confirm value"); 3987 memset(setup->sm_peer_confirm, 0, 16); 3988 } 3989 #endif 3990 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3991 break; 3992 3993 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3994 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3995 sm_pdu_received_in_wrong_state(sm_conn); 3996 break;; 3997 } 3998 3999 // received random value 4000 reverse_128(&packet[1], setup->sm_peer_random); 4001 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4002 break; 4003 #endif 4004 4005 #ifdef ENABLE_LE_PERIPHERAL 4006 // Responder 4007 case SM_RESPONDER_IDLE: 4008 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4009 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4010 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4011 sm_pdu_received_in_wrong_state(sm_conn); 4012 break;; 4013 } 4014 4015 // store pairing request 4016 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4017 4018 // check if IRK completed 4019 switch (sm_conn->sm_irk_lookup_state){ 4020 case IRK_LOOKUP_SUCCEEDED: 4021 case IRK_LOOKUP_FAILED: 4022 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4023 break; 4024 default: 4025 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4026 break; 4027 } 4028 break; 4029 #endif 4030 4031 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4032 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4033 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4034 sm_pdu_received_in_wrong_state(sm_conn); 4035 break; 4036 } 4037 4038 // store public key for DH Key calculation 4039 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4040 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4041 4042 // validate public key 4043 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4044 if (err != 0){ 4045 log_error("sm: peer public key invalid %x", err); 4046 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4047 break; 4048 } 4049 4050 // start calculating dhkey 4051 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); 4052 4053 4054 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4055 if (IS_RESPONDER(sm_conn->sm_role)){ 4056 // responder 4057 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4058 } else { 4059 // initiator 4060 // stk generation method 4061 // passkey entry: notify app to show passkey or to request passkey 4062 switch (setup->sm_stk_generation_method){ 4063 case JUST_WORKS: 4064 case NUMERIC_COMPARISON: 4065 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4066 break; 4067 case PK_RESP_INPUT: 4068 sm_sc_start_calculating_local_confirm(sm_conn); 4069 break; 4070 case PK_INIT_INPUT: 4071 case PK_BOTH_INPUT: 4072 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4073 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4074 break; 4075 } 4076 sm_sc_start_calculating_local_confirm(sm_conn); 4077 break; 4078 case OOB: 4079 // generate Nx 4080 log_info("Generate Na"); 4081 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); 4082 break; 4083 default: 4084 btstack_assert(false); 4085 break; 4086 } 4087 } 4088 break; 4089 4090 case SM_SC_W4_CONFIRMATION: 4091 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4092 sm_pdu_received_in_wrong_state(sm_conn); 4093 break; 4094 } 4095 // received confirm value 4096 reverse_128(&packet[1], setup->sm_peer_confirm); 4097 4098 #ifdef ENABLE_TESTING_SUPPORT 4099 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4100 log_info("testing_support: reset confirm value"); 4101 memset(setup->sm_peer_confirm, 0, 16); 4102 } 4103 #endif 4104 if (IS_RESPONDER(sm_conn->sm_role)){ 4105 // responder 4106 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4107 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4108 // still waiting for passkey 4109 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4110 break; 4111 } 4112 } 4113 sm_sc_start_calculating_local_confirm(sm_conn); 4114 } else { 4115 // initiator 4116 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4117 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); 4118 } else { 4119 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4120 } 4121 } 4122 break; 4123 4124 case SM_SC_W4_PAIRING_RANDOM: 4125 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4126 sm_pdu_received_in_wrong_state(sm_conn); 4127 break; 4128 } 4129 4130 // received random value 4131 reverse_128(&packet[1], setup->sm_peer_nonce); 4132 4133 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4134 // only check for JUST WORK/NC in initiator role OR passkey entry 4135 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4136 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4137 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4138 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4139 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4140 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4141 break; 4142 } 4143 4144 // OOB 4145 if (setup->sm_stk_generation_method == OOB){ 4146 4147 // setup local random, set to zero if remote did not receive our data 4148 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4149 if (IS_RESPONDER(sm_conn->sm_role)){ 4150 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4151 log_info("Reset rb as A does not have OOB data"); 4152 memset(setup->sm_rb, 0, 16); 4153 } else { 4154 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4155 log_info("Use stored rb"); 4156 log_info_hexdump(setup->sm_rb, 16); 4157 } 4158 } else { 4159 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4160 log_info("Reset ra as B does not have OOB data"); 4161 memset(setup->sm_ra, 0, 16); 4162 } else { 4163 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4164 log_info("Use stored ra"); 4165 log_info_hexdump(setup->sm_ra, 16); 4166 } 4167 } 4168 4169 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4170 if (setup->sm_have_oob_data){ 4171 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4172 break; 4173 } 4174 } 4175 4176 // TODO: we only get here for Responder role with JW/NC 4177 sm_sc_state_after_receiving_random(sm_conn); 4178 break; 4179 4180 case SM_SC_W2_CALCULATE_G2: 4181 case SM_SC_W4_CALCULATE_G2: 4182 case SM_SC_W4_CALCULATE_DHKEY: 4183 case SM_SC_W2_CALCULATE_F5_SALT: 4184 case SM_SC_W4_CALCULATE_F5_SALT: 4185 case SM_SC_W2_CALCULATE_F5_MACKEY: 4186 case SM_SC_W4_CALCULATE_F5_MACKEY: 4187 case SM_SC_W2_CALCULATE_F5_LTK: 4188 case SM_SC_W4_CALCULATE_F5_LTK: 4189 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4190 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4191 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4192 case SM_SC_W4_USER_RESPONSE: 4193 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4194 sm_pdu_received_in_wrong_state(sm_conn); 4195 break; 4196 } 4197 // store DHKey Check 4198 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4199 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4200 4201 // have we been only waiting for dhkey check command? 4202 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4203 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4204 } 4205 break; 4206 #endif 4207 4208 #ifdef ENABLE_LE_PERIPHERAL 4209 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4210 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4211 sm_pdu_received_in_wrong_state(sm_conn); 4212 break; 4213 } 4214 4215 // received confirm value 4216 reverse_128(&packet[1], setup->sm_peer_confirm); 4217 4218 #ifdef ENABLE_TESTING_SUPPORT 4219 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4220 log_info("testing_support: reset confirm value"); 4221 memset(setup->sm_peer_confirm, 0, 16); 4222 } 4223 #endif 4224 // notify client to hide shown passkey 4225 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4226 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4227 } 4228 4229 // handle user cancel pairing? 4230 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4231 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4232 break; 4233 } 4234 4235 // wait for user action? 4236 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4237 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4238 break; 4239 } 4240 4241 // calculate and send local_confirm 4242 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); 4243 break; 4244 4245 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4246 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4247 sm_pdu_received_in_wrong_state(sm_conn); 4248 break;; 4249 } 4250 4251 // received random value 4252 reverse_128(&packet[1], setup->sm_peer_random); 4253 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4254 break; 4255 #endif 4256 4257 case SM_PH3_RECEIVE_KEYS: 4258 switch(sm_pdu_code){ 4259 case SM_CODE_ENCRYPTION_INFORMATION: 4260 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4261 reverse_128(&packet[1], setup->sm_peer_ltk); 4262 break; 4263 4264 case SM_CODE_MASTER_IDENTIFICATION: 4265 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4266 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4267 reverse_64(&packet[3], setup->sm_peer_rand); 4268 break; 4269 4270 case SM_CODE_IDENTITY_INFORMATION: 4271 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4272 reverse_128(&packet[1], setup->sm_peer_irk); 4273 break; 4274 4275 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4276 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4277 setup->sm_peer_addr_type = packet[1]; 4278 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4279 break; 4280 4281 case SM_CODE_SIGNING_INFORMATION: 4282 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4283 reverse_128(&packet[1], setup->sm_peer_csrk); 4284 break; 4285 default: 4286 // Unexpected PDU 4287 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4288 break; 4289 } 4290 // done with key distribution? 4291 if (sm_key_distribution_all_received(sm_conn)){ 4292 4293 sm_key_distribution_handle_all_received(sm_conn); 4294 4295 if (IS_RESPONDER(sm_conn->sm_role)){ 4296 sm_key_distribution_complete_responder(sm_conn); 4297 } else { 4298 if (setup->sm_use_secure_connections){ 4299 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4300 } else { 4301 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); 4302 } 4303 } 4304 } 4305 break; 4306 default: 4307 // Unexpected PDU 4308 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4309 break; 4310 } 4311 4312 // try to send next pdu 4313 sm_trigger_run(); 4314 } 4315 4316 // Security Manager Client API 4317 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4318 sm_get_oob_data = get_oob_data_callback; 4319 } 4320 4321 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)){ 4322 sm_get_sc_oob_data = get_sc_oob_data_callback; 4323 } 4324 4325 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4326 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4327 } 4328 4329 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4330 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4331 } 4332 4333 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4334 sm_min_encryption_key_size = min_size; 4335 sm_max_encryption_key_size = max_size; 4336 } 4337 4338 void sm_set_authentication_requirements(uint8_t auth_req){ 4339 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4340 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4341 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4342 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4343 } 4344 #endif 4345 sm_auth_req = auth_req; 4346 } 4347 4348 void sm_set_io_capabilities(io_capability_t io_capability){ 4349 sm_io_capabilities = io_capability; 4350 } 4351 4352 #ifdef ENABLE_LE_PERIPHERAL 4353 void sm_set_request_security(int enable){ 4354 sm_slave_request_security = enable; 4355 } 4356 #endif 4357 4358 void sm_set_er(sm_key_t er){ 4359 (void)memcpy(sm_persistent_er, er, 16); 4360 } 4361 4362 void sm_set_ir(sm_key_t ir){ 4363 (void)memcpy(sm_persistent_ir, ir, 16); 4364 } 4365 4366 // Testing support only 4367 void sm_test_set_irk(sm_key_t irk){ 4368 (void)memcpy(sm_persistent_irk, irk, 16); 4369 dkg_state = DKG_CALC_DHK; 4370 test_use_fixed_local_irk = true; 4371 } 4372 4373 void sm_test_use_fixed_local_csrk(void){ 4374 test_use_fixed_local_csrk = true; 4375 } 4376 4377 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4378 static void sm_ec_generated(void * arg){ 4379 UNUSED(arg); 4380 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4381 // trigger pairing if pending for ec key 4382 sm_trigger_run(); 4383 } 4384 static void sm_ec_generate_new_key(void){ 4385 log_info("sm: generate new ec key"); 4386 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4387 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4388 } 4389 #endif 4390 4391 #ifdef ENABLE_TESTING_SUPPORT 4392 void sm_test_set_pairing_failure(int reason){ 4393 test_pairing_failure = reason; 4394 } 4395 #endif 4396 4397 void sm_init(void){ 4398 4399 if (sm_initialized) return; 4400 4401 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4402 sm_er_ir_set_default(); 4403 4404 // defaults 4405 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4406 | SM_STK_GENERATION_METHOD_OOB 4407 | SM_STK_GENERATION_METHOD_PASSKEY 4408 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4409 4410 sm_max_encryption_key_size = 16; 4411 sm_min_encryption_key_size = 7; 4412 4413 sm_fixed_passkey_in_display_role = 0xffffffffU; 4414 sm_reconstruct_ltk_without_le_device_db_entry = true; 4415 4416 #ifdef USE_CMAC_ENGINE 4417 sm_cmac_active = 0; 4418 #endif 4419 dkg_state = DKG_W4_WORKING; 4420 rau_state = RAU_IDLE; 4421 sm_aes128_state = SM_AES128_IDLE; 4422 sm_address_resolution_test = -1; // no private address to resolve yet 4423 sm_address_resolution_ah_calculation_active = 0; 4424 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4425 sm_address_resolution_general_queue = NULL; 4426 4427 gap_random_adress_update_period = 15 * 60 * 1000L; 4428 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4429 4430 test_use_fixed_local_csrk = false; 4431 4432 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4433 4434 // register for HCI Events from HCI 4435 hci_event_callback_registration.callback = &sm_event_packet_handler; 4436 hci_add_event_handler(&hci_event_callback_registration); 4437 4438 // 4439 btstack_crypto_init(); 4440 4441 // init le_device_db 4442 le_device_db_init(); 4443 4444 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4445 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4446 4447 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4448 sm_ec_generate_new_key(); 4449 #endif 4450 4451 sm_initialized = true; 4452 } 4453 4454 void sm_deinit(void){ 4455 sm_initialized = false; 4456 btstack_run_loop_remove_timer(&sm_run_timer); 4457 } 4458 4459 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4460 sm_fixed_passkey_in_display_role = passkey; 4461 } 4462 4463 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4464 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4465 } 4466 4467 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4468 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4469 if (!hci_con) return NULL; 4470 return &hci_con->sm_connection; 4471 } 4472 4473 // @deprecated: map onto sm_request_pairing 4474 void sm_send_security_request(hci_con_handle_t con_handle){ 4475 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4476 if (!sm_conn) return; 4477 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4478 sm_request_pairing(con_handle); 4479 } 4480 4481 // request pairing 4482 void sm_request_pairing(hci_con_handle_t con_handle){ 4483 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4484 if (!sm_conn) return; // wrong connection 4485 4486 bool have_ltk; 4487 uint8_t ltk[16]; 4488 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4489 if (IS_RESPONDER(sm_conn->sm_role)){ 4490 switch (sm_conn->sm_engine_state){ 4491 case SM_GENERAL_IDLE: 4492 case SM_RESPONDER_IDLE: 4493 switch (sm_conn->sm_irk_lookup_state){ 4494 case IRK_LOOKUP_SUCCEEDED: 4495 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4496 have_ltk = !sm_is_null_key(ltk); 4497 log_info("have ltk %u", have_ltk); 4498 if (have_ltk){ 4499 sm_conn->sm_pairing_requested = 1; 4500 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4501 sm_reencryption_started(sm_conn); 4502 break; 4503 } 4504 /* fall through */ 4505 4506 case IRK_LOOKUP_FAILED: 4507 sm_conn->sm_pairing_requested = 1; 4508 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4509 sm_pairing_started(sm_conn); 4510 break; 4511 default: 4512 log_info("irk lookup pending"); 4513 sm_conn->sm_pairing_requested = 1; 4514 break; 4515 } 4516 break; 4517 default: 4518 break; 4519 } 4520 } else { 4521 // used as a trigger to start central/master/initiator security procedures 4522 switch (sm_conn->sm_engine_state){ 4523 case SM_INITIATOR_CONNECTED: 4524 switch (sm_conn->sm_irk_lookup_state){ 4525 case IRK_LOOKUP_SUCCEEDED: 4526 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4527 have_ltk = !sm_is_null_key(ltk); 4528 log_info("have ltk %u", have_ltk); 4529 if (have_ltk){ 4530 sm_conn->sm_pairing_requested = 1; 4531 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4532 break; 4533 } 4534 /* fall through */ 4535 4536 case IRK_LOOKUP_FAILED: 4537 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4538 break; 4539 default: 4540 log_info("irk lookup pending"); 4541 sm_conn->sm_pairing_requested = 1; 4542 break; 4543 } 4544 break; 4545 case SM_GENERAL_REENCRYPTION_FAILED: 4546 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4547 break; 4548 case SM_GENERAL_IDLE: 4549 sm_conn->sm_pairing_requested = 1; 4550 break; 4551 default: 4552 break; 4553 } 4554 } 4555 sm_trigger_run(); 4556 } 4557 4558 // called by client app on authorization request 4559 void sm_authorization_decline(hci_con_handle_t con_handle){ 4560 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4561 if (!sm_conn) return; // wrong connection 4562 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4563 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4564 } 4565 4566 void sm_authorization_grant(hci_con_handle_t con_handle){ 4567 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4568 if (!sm_conn) return; // wrong connection 4569 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4570 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4571 } 4572 4573 // GAP Bonding API 4574 4575 void sm_bonding_decline(hci_con_handle_t con_handle){ 4576 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4577 if (!sm_conn) return; // wrong connection 4578 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4579 log_info("decline, state %u", sm_conn->sm_engine_state); 4580 switch(sm_conn->sm_engine_state){ 4581 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4582 case SM_SC_W4_USER_RESPONSE: 4583 case SM_SC_W4_CONFIRMATION: 4584 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4585 #endif 4586 case SM_PH1_W4_USER_RESPONSE: 4587 switch (setup->sm_stk_generation_method){ 4588 case PK_RESP_INPUT: 4589 case PK_INIT_INPUT: 4590 case PK_BOTH_INPUT: 4591 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4592 break; 4593 case NUMERIC_COMPARISON: 4594 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4595 break; 4596 case JUST_WORKS: 4597 case OOB: 4598 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4599 break; 4600 default: 4601 btstack_assert(false); 4602 break; 4603 } 4604 break; 4605 default: 4606 break; 4607 } 4608 sm_trigger_run(); 4609 } 4610 4611 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4612 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4613 if (!sm_conn) return; // wrong connection 4614 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4615 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4616 if (setup->sm_use_secure_connections){ 4617 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4618 } else { 4619 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); 4620 } 4621 } 4622 4623 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4624 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4625 sm_sc_prepare_dhkey_check(sm_conn); 4626 } 4627 #endif 4628 4629 sm_trigger_run(); 4630 } 4631 4632 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4633 // for now, it's the same 4634 sm_just_works_confirm(con_handle); 4635 } 4636 4637 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4638 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4639 if (!sm_conn) return; // wrong connection 4640 sm_reset_tk(); 4641 big_endian_store_32(setup->sm_tk, 12, passkey); 4642 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4643 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4644 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); 4645 } 4646 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4647 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4648 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4649 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4650 sm_sc_start_calculating_local_confirm(sm_conn); 4651 } 4652 #endif 4653 sm_trigger_run(); 4654 } 4655 4656 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4657 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4658 if (!sm_conn) return; // wrong connection 4659 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4660 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4661 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4662 switch (action){ 4663 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4664 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4665 flags |= (1u << action); 4666 break; 4667 case SM_KEYPRESS_PASSKEY_CLEARED: 4668 // clear counter, keypress & erased flags + set passkey cleared 4669 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4670 break; 4671 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4672 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4673 // erase actions queued 4674 num_actions--; 4675 if (num_actions == 0u){ 4676 // clear counter, keypress & erased flags 4677 flags &= 0x19u; 4678 } 4679 break; 4680 } 4681 num_actions++; 4682 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4683 break; 4684 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4685 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4686 // enter actions queued 4687 num_actions--; 4688 if (num_actions == 0u){ 4689 // clear counter, keypress & erased flags 4690 flags &= 0x19u; 4691 } 4692 break; 4693 } 4694 num_actions++; 4695 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4696 break; 4697 default: 4698 break; 4699 } 4700 setup->sm_keypress_notification = (num_actions << 5) | flags; 4701 sm_trigger_run(); 4702 } 4703 4704 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4705 static void sm_handle_random_result_oob(void * arg){ 4706 UNUSED(arg); 4707 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4708 sm_trigger_run(); 4709 } 4710 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4711 4712 static btstack_crypto_random_t sm_crypto_random_oob_request; 4713 4714 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4715 sm_sc_oob_callback = callback; 4716 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4717 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4718 return 0; 4719 } 4720 #endif 4721 4722 /** 4723 * @brief Get Identity Resolving state 4724 * @param con_handle 4725 * @return irk_lookup_state_t 4726 */ 4727 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4728 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4729 if (!sm_conn) return IRK_LOOKUP_IDLE; 4730 return sm_conn->sm_irk_lookup_state; 4731 } 4732 4733 /** 4734 * @brief Identify device in LE Device DB 4735 * @param handle 4736 * @returns index from le_device_db or -1 if not found/identified 4737 */ 4738 int sm_le_device_index(hci_con_handle_t con_handle ){ 4739 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4740 if (!sm_conn) return -1; 4741 return sm_conn->sm_le_db_index; 4742 } 4743 4744 static int gap_random_address_type_requires_updates(void){ 4745 switch (gap_random_adress_type){ 4746 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4747 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4748 return 0; 4749 default: 4750 return 1; 4751 } 4752 } 4753 4754 static uint8_t own_address_type(void){ 4755 switch (gap_random_adress_type){ 4756 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4757 return BD_ADDR_TYPE_LE_PUBLIC; 4758 default: 4759 return BD_ADDR_TYPE_LE_RANDOM; 4760 } 4761 } 4762 4763 // GAP LE API 4764 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4765 gap_random_address_update_stop(); 4766 gap_random_adress_type = random_address_type; 4767 hci_le_set_own_address_type(own_address_type()); 4768 if (!gap_random_address_type_requires_updates()) return; 4769 gap_random_address_update_start(); 4770 gap_random_address_trigger(); 4771 } 4772 4773 gap_random_address_type_t gap_random_address_get_mode(void){ 4774 return gap_random_adress_type; 4775 } 4776 4777 void gap_random_address_set_update_period(int period_ms){ 4778 gap_random_adress_update_period = period_ms; 4779 if (!gap_random_address_type_requires_updates()) return; 4780 gap_random_address_update_stop(); 4781 gap_random_address_update_start(); 4782 } 4783 4784 void gap_random_address_set(const bd_addr_t addr){ 4785 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4786 (void)memcpy(sm_random_address, addr, 6); 4787 rau_state = RAU_SET_ADDRESS; 4788 sm_trigger_run(); 4789 } 4790 4791 #ifdef ENABLE_LE_PERIPHERAL 4792 /* 4793 * @brief Set Advertisement Paramters 4794 * @param adv_int_min 4795 * @param adv_int_max 4796 * @param adv_type 4797 * @param direct_address_type 4798 * @param direct_address 4799 * @param channel_map 4800 * @param filter_policy 4801 * 4802 * @note own_address_type is used from gap_random_address_set_mode 4803 */ 4804 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4805 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4806 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4807 direct_address_typ, direct_address, channel_map, filter_policy); 4808 } 4809 #endif 4810 4811 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4812 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4813 // wrong connection 4814 if (!sm_conn) return 0; 4815 // already encrypted 4816 if (sm_conn->sm_connection_encrypted) return 0; 4817 // irk status? 4818 switch(sm_conn->sm_irk_lookup_state){ 4819 case IRK_LOOKUP_FAILED: 4820 // done, cannot setup encryption 4821 return 0; 4822 case IRK_LOOKUP_SUCCEEDED: 4823 break; 4824 default: 4825 // IR Lookup pending 4826 return 1; 4827 } 4828 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 4829 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 4830 if (sm_conn->sm_role){ 4831 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 4832 } else { 4833 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4834 } 4835 } 4836 4837 void sm_set_secure_connections_only_mode(bool enable){ 4838 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4839 sm_sc_only_mode = enable; 4840 #else 4841 // SC Only mode not possible without support for SC 4842 btstack_assert(enable == false); 4843 #endif 4844 } 4845 4846 const uint8_t * gap_get_persistent_irk(void){ 4847 return sm_persistent_irk; 4848 } 4849 4850 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 4851 uint16_t i; 4852 for (i=0; i < le_device_db_max_count(); i++){ 4853 bd_addr_t entry_address; 4854 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 4855 le_device_db_info(i, &entry_address_type, entry_address, NULL); 4856 // skip unused entries 4857 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 4858 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 4859 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 4860 hci_remove_le_device_db_entry_from_resolving_list(i); 4861 #endif 4862 le_device_db_remove(i); 4863 break; 4864 } 4865 } 4866 } 4867