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