1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 } random_address_update_t; 111 112 typedef enum { 113 CMAC_IDLE, 114 CMAC_CALC_SUBKEYS, 115 CMAC_W4_SUBKEYS, 116 CMAC_CALC_MI, 117 CMAC_W4_MI, 118 CMAC_CALC_MLAST, 119 CMAC_W4_MLAST 120 } cmac_state_t; 121 122 typedef enum { 123 JUST_WORKS, 124 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 125 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 126 PK_BOTH_INPUT, // Only input on both, both input PK 127 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 128 OOB // OOB available on one (SC) or both sides (legacy) 129 } stk_generation_method_t; 130 131 typedef enum { 132 SM_USER_RESPONSE_IDLE, 133 SM_USER_RESPONSE_PENDING, 134 SM_USER_RESPONSE_CONFIRM, 135 SM_USER_RESPONSE_PASSKEY, 136 SM_USER_RESPONSE_DECLINE 137 } sm_user_response_t; 138 139 typedef enum { 140 SM_AES128_IDLE, 141 SM_AES128_ACTIVE 142 } sm_aes128_state_t; 143 144 typedef enum { 145 ADDRESS_RESOLUTION_IDLE, 146 ADDRESS_RESOLUTION_GENERAL, 147 ADDRESS_RESOLUTION_FOR_CONNECTION, 148 } address_resolution_mode_t; 149 150 typedef enum { 151 ADDRESS_RESOLUTION_SUCCEEDED, 152 ADDRESS_RESOLUTION_FAILED, 153 } address_resolution_event_t; 154 155 typedef enum { 156 EC_KEY_GENERATION_IDLE, 157 EC_KEY_GENERATION_ACTIVE, 158 EC_KEY_GENERATION_DONE, 159 } ec_key_generation_state_t; 160 161 typedef enum { 162 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 163 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 165 } sm_state_var_t; 166 167 typedef enum { 168 SM_SC_OOB_IDLE, 169 SM_SC_OOB_W4_RANDOM, 170 SM_SC_OOB_W2_CALC_CONFIRM, 171 SM_SC_OOB_W4_CONFIRM, 172 } sm_sc_oob_state_t; 173 174 typedef uint8_t sm_key24_t[3]; 175 typedef uint8_t sm_key56_t[7]; 176 typedef uint8_t sm_key256_t[32]; 177 178 // 179 // GLOBAL DATA 180 // 181 182 static bool sm_initialized; 183 184 static bool test_use_fixed_local_csrk; 185 static bool test_use_fixed_local_irk; 186 187 #ifdef ENABLE_TESTING_SUPPORT 188 static uint8_t test_pairing_failure; 189 #endif 190 191 // configuration 192 static uint8_t sm_accepted_stk_generation_methods; 193 static uint8_t sm_max_encryption_key_size; 194 static uint8_t sm_min_encryption_key_size; 195 static uint8_t sm_auth_req = 0; 196 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static bool sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_PERIPHERAL 201 static uint8_t sm_slave_request_security; 202 #endif 203 204 #ifdef ENABLE_LE_SECURE_CONNECTIONS 205 static bool sm_sc_only_mode; 206 static uint8_t sm_sc_oob_random[16]; 207 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 208 static sm_sc_oob_state_t sm_sc_oob_state; 209 #endif 210 211 212 static bool sm_persistent_keys_random_active; 213 static const btstack_tlv_t * sm_tlv_impl; 214 static void * sm_tlv_context; 215 216 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 217 static sm_key_t sm_persistent_er; 218 static sm_key_t sm_persistent_ir; 219 220 // derived from sm_persistent_ir 221 static sm_key_t sm_persistent_dhk; 222 static sm_key_t sm_persistent_irk; 223 static derived_key_generation_t dkg_state; 224 225 // derived from sm_persistent_er 226 // .. 227 228 // random address update 229 static random_address_update_t rau_state; 230 static bd_addr_t sm_random_address; 231 232 #ifdef USE_CMAC_ENGINE 233 // CMAC Calculation: General 234 static btstack_crypto_aes128_cmac_t sm_cmac_request; 235 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 236 static uint8_t sm_cmac_active; 237 static uint8_t sm_cmac_hash[16]; 238 #endif 239 240 // CMAC for ATT Signed Writes 241 #ifdef ENABLE_LE_SIGNED_WRITE 242 static uint16_t sm_cmac_signed_write_message_len; 243 static uint8_t sm_cmac_signed_write_header[3]; 244 static const uint8_t * sm_cmac_signed_write_message; 245 static uint8_t sm_cmac_signed_write_sign_counter[4]; 246 #endif 247 248 // CMAC for Secure Connection functions 249 #ifdef ENABLE_LE_SECURE_CONNECTIONS 250 static sm_connection_t * sm_cmac_connection; 251 static uint8_t sm_cmac_sc_buffer[80]; 252 #endif 253 254 // resolvable private address lookup / CSRK calculation 255 static int sm_address_resolution_test; 256 static uint8_t sm_address_resolution_addr_type; 257 static bd_addr_t sm_address_resolution_address; 258 static void * sm_address_resolution_context; 259 static address_resolution_mode_t sm_address_resolution_mode; 260 static btstack_linked_list_t sm_address_resolution_general_queue; 261 262 // aes128 crypto engine. 263 static sm_aes128_state_t sm_aes128_state; 264 265 // crypto 266 static btstack_crypto_random_t sm_crypto_random_request; 267 static btstack_crypto_aes128_t sm_crypto_aes128_request; 268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 269 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 270 #endif 271 272 // temp storage for random data 273 static uint8_t sm_random_data[8]; 274 static uint8_t sm_aes128_key[16]; 275 static uint8_t sm_aes128_plaintext[16]; 276 static uint8_t sm_aes128_ciphertext[16]; 277 278 // to receive events 279 static btstack_packet_callback_registration_t hci_event_callback_registration; 280 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 281 static btstack_packet_callback_registration_t l2cap_event_callback_registration; 282 #endif 283 284 /* to dispatch sm event */ 285 static btstack_linked_list_t sm_event_handlers; 286 287 /* to schedule calls to sm_run */ 288 static btstack_timer_source_t sm_run_timer; 289 290 // LE Secure Connections 291 #ifdef ENABLE_LE_SECURE_CONNECTIONS 292 static ec_key_generation_state_t ec_key_generation_state; 293 static uint8_t ec_q[64]; 294 #endif 295 296 // 297 // Volume 3, Part H, Chapter 24 298 // "Security shall be initiated by the Security Manager in the device in the master role. 299 // The device in the slave role shall be the responding device." 300 // -> master := initiator, slave := responder 301 // 302 303 // data needed for security setup 304 typedef struct sm_setup_context { 305 306 btstack_timer_source_t sm_timeout; 307 308 // user response, (Phase 1 and/or 2) 309 uint8_t sm_user_response; 310 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 311 312 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 313 uint8_t sm_key_distribution_send_set; 314 uint8_t sm_key_distribution_sent_set; 315 uint8_t sm_key_distribution_expected_set; 316 uint8_t sm_key_distribution_received_set; 317 318 // Phase 2 (Pairing over SMP) 319 stk_generation_method_t sm_stk_generation_method; 320 sm_key_t sm_tk; 321 uint8_t sm_have_oob_data; 322 uint8_t sm_use_secure_connections; 323 324 sm_key_t sm_c1_t3_value; // c1 calculation 325 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 326 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 327 sm_key_t sm_local_random; 328 sm_key_t sm_local_confirm; 329 sm_key_t sm_peer_random; 330 sm_key_t sm_peer_confirm; 331 uint8_t sm_m_addr_type; // address and type can be removed 332 uint8_t sm_s_addr_type; // '' 333 bd_addr_t sm_m_address; // '' 334 bd_addr_t sm_s_address; // '' 335 sm_key_t sm_ltk; 336 337 uint8_t sm_state_vars; 338 #ifdef ENABLE_LE_SECURE_CONNECTIONS 339 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 340 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 341 sm_key_t sm_local_nonce; // might be combined with sm_local_random 342 uint8_t sm_dhkey[32]; 343 sm_key_t sm_peer_dhkey_check; 344 sm_key_t sm_local_dhkey_check; 345 sm_key_t sm_ra; 346 sm_key_t sm_rb; 347 sm_key_t sm_t; // used for f5 and h6 348 sm_key_t sm_mackey; 349 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 350 #endif 351 352 // Phase 3 353 354 // key distribution, we generate 355 uint16_t sm_local_y; 356 uint16_t sm_local_div; 357 uint16_t sm_local_ediv; 358 uint8_t sm_local_rand[8]; 359 sm_key_t sm_local_ltk; 360 sm_key_t sm_local_csrk; 361 sm_key_t sm_local_irk; 362 // sm_local_address/addr_type not needed 363 364 // key distribution, received from peer 365 uint16_t sm_peer_y; 366 uint16_t sm_peer_div; 367 uint16_t sm_peer_ediv; 368 uint8_t sm_peer_rand[8]; 369 sm_key_t sm_peer_ltk; 370 sm_key_t sm_peer_irk; 371 sm_key_t sm_peer_csrk; 372 uint8_t sm_peer_addr_type; 373 bd_addr_t sm_peer_address; 374 #ifdef ENABLE_LE_SIGNED_WRITE 375 int sm_le_device_index; 376 #endif 377 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 378 link_key_t sm_link_key; 379 link_key_type_t sm_link_key_type; 380 #endif 381 } sm_setup_context_t; 382 383 // 384 static sm_setup_context_t the_setup; 385 static sm_setup_context_t * setup = &the_setup; 386 387 // active connection - the one for which the_setup is used for 388 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 389 390 // @return 1 if oob data is available 391 // stores oob data in provided 16 byte buffer if not null 392 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 393 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); 394 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 395 396 static void sm_run(void); 397 static void sm_state_reset(void); 398 static void sm_done_for_handle(hci_con_handle_t con_handle); 399 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 400 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk); 401 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 402 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 403 #endif 404 static inline int sm_calc_actual_encryption_key_size(int other); 405 static int sm_validate_stk_generation_method(void); 406 static void sm_handle_encryption_result_address_resolution(void *arg); 407 static void sm_handle_encryption_result_dkg_dhk(void *arg); 408 static void sm_handle_encryption_result_dkg_irk(void *arg); 409 static void sm_handle_encryption_result_enc_a(void *arg); 410 static void sm_handle_encryption_result_enc_b(void *arg); 411 static void sm_handle_encryption_result_enc_c(void *arg); 412 static void sm_handle_encryption_result_enc_csrk(void *arg); 413 static void sm_handle_encryption_result_enc_d(void * arg); 414 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 415 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 416 #ifdef ENABLE_LE_PERIPHERAL 417 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 418 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 419 #endif 420 static void sm_handle_encryption_result_enc_stk(void *arg); 421 static void sm_handle_encryption_result_rau(void *arg); 422 static void sm_handle_random_result_ph2_tk(void * arg); 423 static void sm_handle_random_result_rau(void * arg); 424 #ifdef ENABLE_LE_SECURE_CONNECTIONS 425 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)); 426 static void sm_ec_generate_new_key(void); 427 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 428 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 429 static int sm_passkey_entry(stk_generation_method_t method); 430 #endif 431 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 432 433 static void log_info_hex16(const char * name, uint16_t value){ 434 log_info("%-6s 0x%04x", name, value); 435 } 436 437 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 438 // return packet[0]; 439 // } 440 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 441 return packet[1]; 442 } 443 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 444 return packet[2]; 445 } 446 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 447 return packet[3]; 448 } 449 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 450 return packet[4]; 451 } 452 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 453 return packet[5]; 454 } 455 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 456 return packet[6]; 457 } 458 459 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 460 packet[0] = code; 461 } 462 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 463 packet[1] = io_capability; 464 } 465 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 466 packet[2] = oob_data_flag; 467 } 468 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 469 packet[3] = auth_req; 470 } 471 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 472 packet[4] = max_encryption_key_size; 473 } 474 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 475 packet[5] = initiator_key_distribution; 476 } 477 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 478 packet[6] = responder_key_distribution; 479 } 480 481 static bool sm_is_null_random(uint8_t random[8]){ 482 return btstack_is_null(random, 8); 483 } 484 485 static bool sm_is_null_key(uint8_t * key){ 486 return btstack_is_null(key, 16); 487 } 488 489 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 490 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 491 UNUSED(ts); 492 sm_run(); 493 } 494 static void sm_trigger_run(void){ 495 if (!sm_initialized) return; 496 (void)btstack_run_loop_remove_timer(&sm_run_timer); 497 btstack_run_loop_set_timer(&sm_run_timer, 0); 498 btstack_run_loop_add_timer(&sm_run_timer); 499 } 500 501 // Key utils 502 static void sm_reset_tk(void){ 503 int i; 504 for (i=0;i<16;i++){ 505 setup->sm_tk[i] = 0; 506 } 507 } 508 509 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 510 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 511 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 512 int i; 513 for (i = max_encryption_size ; i < 16 ; i++){ 514 key[15-i] = 0; 515 } 516 } 517 518 // ER / IR checks 519 static void sm_er_ir_set_default(void){ 520 int i; 521 for (i=0;i<16;i++){ 522 sm_persistent_er[i] = 0x30 + i; 523 sm_persistent_ir[i] = 0x90 + i; 524 } 525 } 526 527 static int sm_er_is_default(void){ 528 int i; 529 for (i=0;i<16;i++){ 530 if (sm_persistent_er[i] != (0x30+i)) return 0; 531 } 532 return 1; 533 } 534 535 static int sm_ir_is_default(void){ 536 int i; 537 for (i=0;i<16;i++){ 538 if (sm_persistent_ir[i] != (0x90+i)) return 0; 539 } 540 return 1; 541 } 542 543 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 544 UNUSED(channel); 545 546 // log event 547 hci_dump_packet(packet_type, 1, packet, size); 548 // dispatch to all event handlers 549 btstack_linked_list_iterator_t it; 550 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 551 while (btstack_linked_list_iterator_has_next(&it)){ 552 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 553 entry->callback(packet_type, 0, packet, size); 554 } 555 } 556 557 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){ 558 event[0] = type; 559 event[1] = event_size - 2; 560 little_endian_store_16(event, 2, con_handle); 561 event[4] = addr_type; 562 reverse_bd_addr(address, &event[5]); 563 } 564 565 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 566 uint8_t event[11]; 567 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 568 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 569 } 570 571 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){ 572 // fetch addr and addr type from db, only called for valid entries 573 bd_addr_t identity_address; 574 int identity_address_type; 575 le_device_db_info(index, &identity_address_type, identity_address, NULL); 576 577 uint8_t event[20]; 578 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 579 event[11] = identity_address_type; 580 reverse_bd_addr(identity_address, &event[12]); 581 little_endian_store_16(event, 18, index); 582 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 583 } 584 585 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){ 586 uint8_t event[12]; 587 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 588 event[11] = status; 589 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 590 } 591 592 593 static void sm_reencryption_started(sm_connection_t * sm_conn){ 594 595 if (sm_conn->sm_reencryption_active) return; 596 597 sm_conn->sm_reencryption_active = true; 598 599 int identity_addr_type; 600 bd_addr_t identity_addr; 601 if (sm_conn->sm_le_db_index >= 0){ 602 // fetch addr and addr type from db, only called for valid entries 603 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 604 } else { 605 // for legacy pairing with LTK re-construction, use current peer addr 606 identity_addr_type = sm_conn->sm_peer_addr_type; 607 // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy 608 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 609 } 610 611 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 612 } 613 614 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 615 616 if (!sm_conn->sm_reencryption_active) return; 617 618 sm_conn->sm_reencryption_active = false; 619 620 int identity_addr_type; 621 bd_addr_t identity_addr; 622 if (sm_conn->sm_le_db_index >= 0){ 623 // fetch addr and addr type from db, only called for valid entries 624 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 625 } else { 626 // for legacy pairing with LTK re-construction, use current peer addr 627 identity_addr_type = sm_conn->sm_peer_addr_type; 628 // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy 629 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 630 } 631 632 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 633 } 634 635 static void sm_pairing_started(sm_connection_t * sm_conn){ 636 637 if (sm_conn->sm_pairing_active) return; 638 639 sm_conn->sm_pairing_active = true; 640 641 uint8_t event[11]; 642 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 643 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 644 } 645 646 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 647 648 if (!sm_conn->sm_pairing_active) return; 649 650 sm_conn->sm_pairing_active = false; 651 652 uint8_t event[13]; 653 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 654 event[11] = status; 655 event[12] = reason; 656 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 657 } 658 659 // SMP Timeout implementation 660 661 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 662 // the Security Manager Timer shall be reset and started. 663 // 664 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 665 // 666 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 667 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 668 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 669 // established. 670 671 static void sm_timeout_handler(btstack_timer_source_t * timer){ 672 log_info("SM timeout"); 673 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 674 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 675 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 676 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 677 sm_done_for_handle(sm_conn->sm_handle); 678 679 // trigger handling of next ready connection 680 sm_run(); 681 } 682 static void sm_timeout_start(sm_connection_t * sm_conn){ 683 btstack_run_loop_remove_timer(&setup->sm_timeout); 684 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 685 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 686 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 687 btstack_run_loop_add_timer(&setup->sm_timeout); 688 } 689 static void sm_timeout_stop(void){ 690 btstack_run_loop_remove_timer(&setup->sm_timeout); 691 } 692 static void sm_timeout_reset(sm_connection_t * sm_conn){ 693 sm_timeout_stop(); 694 sm_timeout_start(sm_conn); 695 } 696 697 // end of sm timeout 698 699 // GAP Random Address updates 700 static gap_random_address_type_t gap_random_adress_type; 701 static btstack_timer_source_t gap_random_address_update_timer; 702 static uint32_t gap_random_adress_update_period; 703 704 static void gap_random_address_trigger(void){ 705 log_info("gap_random_address_trigger, state %u", rau_state); 706 if (rau_state != RAU_IDLE) return; 707 rau_state = RAU_GET_RANDOM; 708 sm_trigger_run(); 709 } 710 711 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 712 UNUSED(timer); 713 714 log_info("GAP Random Address Update due"); 715 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 716 btstack_run_loop_add_timer(&gap_random_address_update_timer); 717 gap_random_address_trigger(); 718 } 719 720 static void gap_random_address_update_start(void){ 721 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 722 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 723 btstack_run_loop_add_timer(&gap_random_address_update_timer); 724 } 725 726 static void gap_random_address_update_stop(void){ 727 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 728 } 729 730 // ah(k,r) helper 731 // r = padding || r 732 // r - 24 bit value 733 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 734 // r'= padding || r 735 memset(r_prime, 0, 16); 736 (void)memcpy(&r_prime[13], r, 3); 737 } 738 739 // d1 helper 740 // d' = padding || r || d 741 // d,r - 16 bit values 742 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 743 // d'= padding || r || d 744 memset(d1_prime, 0, 16); 745 big_endian_store_16(d1_prime, 12, r); 746 big_endian_store_16(d1_prime, 14, d); 747 } 748 749 // calculate arguments for first AES128 operation in C1 function 750 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){ 751 752 // p1 = pres || preq || rat’ || iat’ 753 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 754 // cant octet of pres becomes the most significant octet of p1. 755 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 756 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 757 // p1 is 0x05000800000302070710000001010001." 758 759 sm_key_t p1; 760 reverse_56(pres, &p1[0]); 761 reverse_56(preq, &p1[7]); 762 p1[14] = rat; 763 p1[15] = iat; 764 log_info_key("p1", p1); 765 log_info_key("r", r); 766 767 // t1 = r xor p1 768 int i; 769 for (i=0;i<16;i++){ 770 t1[i] = r[i] ^ p1[i]; 771 } 772 log_info_key("t1", t1); 773 } 774 775 // calculate arguments for second AES128 operation in C1 function 776 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 777 // p2 = padding || ia || ra 778 // "The least significant octet of ra becomes the least significant octet of p2 and 779 // the most significant octet of padding becomes the most significant octet of p2. 780 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 781 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 782 783 sm_key_t p2; 784 // cppcheck-suppress uninitvar ; p2 is reported as uninitialized 785 memset(p2, 0, 16); 786 (void)memcpy(&p2[4], ia, 6); 787 (void)memcpy(&p2[10], ra, 6); 788 log_info_key("p2", p2); 789 790 // c1 = e(k, t2_xor_p2) 791 int i; 792 for (i=0;i<16;i++){ 793 t3[i] = t2[i] ^ p2[i]; 794 } 795 log_info_key("t3", t3); 796 } 797 798 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 799 log_info_key("r1", r1); 800 log_info_key("r2", r2); 801 (void)memcpy(&r_prime[8], &r2[8], 8); 802 (void)memcpy(&r_prime[0], &r1[8], 8); 803 } 804 805 806 // decide on stk generation based on 807 // - pairing request 808 // - io capabilities 809 // - OOB data availability 810 static void sm_setup_tk(void){ 811 812 // horizontal: initiator capabilities 813 // vertial: responder capabilities 814 static const stk_generation_method_t stk_generation_method [5] [5] = { 815 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 816 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 817 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 818 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 819 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 820 }; 821 822 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 823 #ifdef ENABLE_LE_SECURE_CONNECTIONS 824 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 825 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 826 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 827 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 828 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 829 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 830 }; 831 #endif 832 833 // default: just works 834 setup->sm_stk_generation_method = JUST_WORKS; 835 836 #ifdef ENABLE_LE_SECURE_CONNECTIONS 837 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 838 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 839 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 840 #else 841 setup->sm_use_secure_connections = 0; 842 #endif 843 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 844 845 846 // decide if OOB will be used based on SC vs. Legacy and oob flags 847 bool use_oob; 848 if (setup->sm_use_secure_connections){ 849 // In LE Secure Connections pairing, the out of band method is used if at least 850 // one device has the peer device's out of band authentication data available. 851 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 852 } else { 853 // In LE legacy pairing, the out of band method is used if both the devices have 854 // the other device's out of band authentication data available. 855 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 856 } 857 if (use_oob){ 858 log_info("SM: have OOB data"); 859 log_info_key("OOB", setup->sm_tk); 860 setup->sm_stk_generation_method = OOB; 861 return; 862 } 863 864 // If both devices have not set the MITM option in the Authentication Requirements 865 // Flags, then the IO capabilities shall be ignored and the Just Works association 866 // model shall be used. 867 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 868 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 869 log_info("SM: MITM not required by both -> JUST WORKS"); 870 return; 871 } 872 873 // Reset TK as it has been setup in sm_init_setup 874 sm_reset_tk(); 875 876 // Also use just works if unknown io capabilites 877 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 878 return; 879 } 880 881 // Otherwise the IO capabilities of the devices shall be used to determine the 882 // pairing method as defined in Table 2.4. 883 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 884 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 885 886 #ifdef ENABLE_LE_SECURE_CONNECTIONS 887 // table not define by default 888 if (setup->sm_use_secure_connections){ 889 generation_method = stk_generation_method_with_secure_connection; 890 } 891 #endif 892 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 893 894 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 895 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 896 } 897 898 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 899 int flags = 0; 900 if (key_set & SM_KEYDIST_ENC_KEY){ 901 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 902 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 903 } 904 if (key_set & SM_KEYDIST_ID_KEY){ 905 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 906 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 907 } 908 if (key_set & SM_KEYDIST_SIGN){ 909 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 910 } 911 return flags; 912 } 913 914 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 915 setup->sm_key_distribution_received_set = 0; 916 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 917 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 918 setup->sm_key_distribution_sent_set = 0; 919 #ifdef ENABLE_LE_SIGNED_WRITE 920 setup->sm_le_device_index = -1; 921 #endif 922 } 923 924 // CSRK Key Lookup 925 926 927 static int sm_address_resolution_idle(void){ 928 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 929 } 930 931 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){ 932 (void)memcpy(sm_address_resolution_address, addr, 6); 933 sm_address_resolution_addr_type = addr_type; 934 sm_address_resolution_test = 0; 935 sm_address_resolution_mode = mode; 936 sm_address_resolution_context = context; 937 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 938 } 939 940 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 941 // check if already in list 942 btstack_linked_list_iterator_t it; 943 sm_lookup_entry_t * entry; 944 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 945 while(btstack_linked_list_iterator_has_next(&it)){ 946 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 947 if (entry->address_type != address_type) continue; 948 if (memcmp(entry->address, address, 6)) continue; 949 // already in list 950 return BTSTACK_BUSY; 951 } 952 entry = btstack_memory_sm_lookup_entry_get(); 953 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 954 entry->address_type = (bd_addr_type_t) address_type; 955 (void)memcpy(entry->address, address, 6); 956 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 957 sm_trigger_run(); 958 return 0; 959 } 960 961 // CMAC calculation using AES Engineq 962 #ifdef USE_CMAC_ENGINE 963 964 static void sm_cmac_done_trampoline(void * arg){ 965 UNUSED(arg); 966 sm_cmac_active = 0; 967 (*sm_cmac_done_callback)(sm_cmac_hash); 968 sm_trigger_run(); 969 } 970 971 int sm_cmac_ready(void){ 972 return sm_cmac_active == 0u; 973 } 974 #endif 975 976 #ifdef ENABLE_LE_SECURE_CONNECTIONS 977 // generic cmac calculation 978 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)){ 979 sm_cmac_active = 1; 980 sm_cmac_done_callback = done_callback; 981 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 982 } 983 #endif 984 985 // cmac for ATT Message signing 986 #ifdef ENABLE_LE_SIGNED_WRITE 987 988 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)){ 989 sm_cmac_active = 1; 990 sm_cmac_done_callback = done_callback; 991 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 992 } 993 994 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 995 if (offset >= sm_cmac_signed_write_message_len) { 996 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 997 return 0; 998 } 999 1000 offset = sm_cmac_signed_write_message_len - 1 - offset; 1001 1002 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 1003 if (offset < 3){ 1004 return sm_cmac_signed_write_header[offset]; 1005 } 1006 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1007 if (offset < actual_message_len_incl_header){ 1008 return sm_cmac_signed_write_message[offset - 3]; 1009 } 1010 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1011 } 1012 1013 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)){ 1014 // ATT Message Signing 1015 sm_cmac_signed_write_header[0] = opcode; 1016 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1017 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1018 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1019 sm_cmac_signed_write_message = message; 1020 sm_cmac_signed_write_message_len = total_message_len; 1021 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1022 } 1023 #endif 1024 1025 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1026 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1027 uint8_t event[12]; 1028 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1029 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1030 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1031 } 1032 1033 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn, uint8_t event_type){ 1034 uint8_t event[16]; 1035 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1036 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, 1037 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1038 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1039 little_endian_store_32(event, 12, passkey); 1040 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1041 } 1042 1043 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1044 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1045 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1046 sm_conn->sm_pairing_active = true; 1047 switch (setup->sm_stk_generation_method){ 1048 case PK_RESP_INPUT: 1049 if (IS_RESPONDER(sm_conn->sm_role)){ 1050 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1051 } else { 1052 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); 1053 } 1054 break; 1055 case PK_INIT_INPUT: 1056 if (IS_RESPONDER(sm_conn->sm_role)){ 1057 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); 1058 } else { 1059 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1060 } 1061 break; 1062 case PK_BOTH_INPUT: 1063 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1064 break; 1065 case NUMERIC_COMPARISON: 1066 sm_trigger_user_response_passkey(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1067 break; 1068 case JUST_WORKS: 1069 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1070 break; 1071 case OOB: 1072 // client already provided OOB data, let's skip notification. 1073 break; 1074 default: 1075 btstack_assert(false); 1076 break; 1077 } 1078 } 1079 1080 static bool sm_key_distribution_all_received(void) { 1081 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, setup->sm_key_distribution_expected_set); 1082 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 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 setup->sm_have_oob_data = 0; 1130 sm_reset_tk(); 1131 } 1132 1133 static void sm_init_setup(sm_connection_t * sm_conn){ 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 if (sm_get_oob_data != NULL) { 1140 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1141 } 1142 1143 // if available and SC supported, also ask for SC OOB Data 1144 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1145 memset(setup->sm_ra, 0, 16); 1146 memset(setup->sm_rb, 0, 16); 1147 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1148 if (sm_get_sc_oob_data != NULL){ 1149 if (IS_RESPONDER(sm_conn->sm_role)){ 1150 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1151 sm_conn->sm_peer_addr_type, 1152 sm_conn->sm_peer_address, 1153 setup->sm_peer_confirm, 1154 setup->sm_ra); 1155 } else { 1156 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1157 sm_conn->sm_peer_addr_type, 1158 sm_conn->sm_peer_address, 1159 setup->sm_peer_confirm, 1160 setup->sm_rb); 1161 } 1162 } else { 1163 setup->sm_have_oob_data = 0; 1164 } 1165 } 1166 #endif 1167 1168 sm_pairing_packet_t * local_packet; 1169 if (IS_RESPONDER(sm_conn->sm_role)){ 1170 // slave 1171 local_packet = &setup->sm_s_pres; 1172 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1173 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1174 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1175 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1176 } else { 1177 // master 1178 local_packet = &setup->sm_m_preq; 1179 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1180 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1181 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1182 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1183 1184 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1185 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1186 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1187 } 1188 1189 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1190 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1191 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1192 // enable SC for SC only mode 1193 if (sm_sc_only_mode){ 1194 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1195 max_encryption_key_size = 16; 1196 } 1197 #endif 1198 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1199 // set CT2 if SC + Bonding + CTKD 1200 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1201 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1202 auth_req |= SM_AUTHREQ_CT2; 1203 } 1204 #endif 1205 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1206 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1207 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1208 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1209 } 1210 1211 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1212 1213 sm_pairing_packet_t * remote_packet; 1214 uint8_t keys_to_send; 1215 uint8_t keys_to_receive; 1216 if (IS_RESPONDER(sm_conn->sm_role)){ 1217 // slave / responder 1218 remote_packet = &setup->sm_m_preq; 1219 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1220 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1221 } else { 1222 // master / initiator 1223 remote_packet = &setup->sm_s_pres; 1224 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1225 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1226 } 1227 1228 // check key size 1229 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1230 // SC Only mandates 128 bit key size 1231 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1232 return SM_REASON_ENCRYPTION_KEY_SIZE; 1233 } 1234 #endif 1235 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1236 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1237 1238 // decide on STK generation method / SC 1239 sm_setup_tk(); 1240 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1241 1242 // check if STK generation method is acceptable by client 1243 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1244 1245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1246 // Check LE SC Only mode 1247 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1248 log_info("SC Only mode active but SC not possible"); 1249 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1250 } 1251 1252 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1253 if (setup->sm_use_secure_connections){ 1254 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1255 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1256 } 1257 #endif 1258 1259 // identical to responder 1260 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1261 1262 // JUST WORKS doens't provide authentication 1263 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1264 1265 return 0; 1266 } 1267 1268 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1269 1270 // cache and reset context 1271 int matched_device_id = sm_address_resolution_test; 1272 address_resolution_mode_t mode = sm_address_resolution_mode; 1273 void * context = sm_address_resolution_context; 1274 1275 // reset context 1276 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1277 sm_address_resolution_context = NULL; 1278 sm_address_resolution_test = -1; 1279 hci_con_handle_t con_handle = 0; 1280 1281 sm_connection_t * sm_connection; 1282 sm_key_t ltk; 1283 bool have_ltk; 1284 #ifdef ENABLE_LE_CENTRAL 1285 bool trigger_pairing; 1286 #endif 1287 switch (mode){ 1288 case ADDRESS_RESOLUTION_GENERAL: 1289 break; 1290 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1291 sm_connection = (sm_connection_t *) context; 1292 con_handle = sm_connection->sm_handle; 1293 1294 // have ltk -> start encryption / send security request 1295 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1296 // "When a bond has been created between two devices, any reconnection should result in the local device 1297 // enabling or requesting encryption with the remote device before initiating any service request." 1298 1299 switch (event){ 1300 case ADDRESS_RESOLUTION_SUCCEEDED: 1301 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1302 sm_connection->sm_le_db_index = matched_device_id; 1303 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1304 1305 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1306 have_ltk = !sm_is_null_key(ltk); 1307 1308 if (sm_connection->sm_role) { 1309 #ifdef ENABLE_LE_PERIPHERAL 1310 // IRK required before, continue 1311 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1312 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1313 break; 1314 } 1315 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1316 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1317 break; 1318 } 1319 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1320 sm_connection->sm_pairing_requested = 0; 1321 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1322 // trigger security request for Proactive Authentication if LTK available 1323 trigger_security_request = trigger_security_request || have_ltk; 1324 #endif 1325 1326 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1327 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1328 1329 if (trigger_security_request){ 1330 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1331 if (have_ltk){ 1332 sm_reencryption_started(sm_connection); 1333 } else { 1334 sm_pairing_started(sm_connection); 1335 } 1336 sm_trigger_run(); 1337 } 1338 #endif 1339 } else { 1340 1341 #ifdef ENABLE_LE_CENTRAL 1342 // check if pairing already requested and reset requests 1343 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1344 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1345 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1346 sm_connection->sm_security_request_received = 0; 1347 sm_connection->sm_pairing_requested = 0; 1348 bool trigger_reencryption = false; 1349 1350 if (have_ltk){ 1351 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1352 trigger_reencryption = true; 1353 #else 1354 if (trigger_pairing){ 1355 trigger_reencryption = true; 1356 } else { 1357 log_info("central: defer enabling encryption for bonded device"); 1358 } 1359 #endif 1360 } 1361 1362 if (trigger_reencryption){ 1363 log_info("central: enable encryption for bonded device"); 1364 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1365 break; 1366 } 1367 1368 // pairing_request -> send pairing request 1369 if (trigger_pairing){ 1370 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1371 break; 1372 } 1373 #endif 1374 } 1375 break; 1376 case ADDRESS_RESOLUTION_FAILED: 1377 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1378 if (sm_connection->sm_role) { 1379 #ifdef ENABLE_LE_PERIPHERAL 1380 // LTK request received before, IRK required -> negative LTK reply 1381 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1382 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1383 } 1384 // send security request if requested 1385 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1386 sm_connection->sm_pairing_requested = 0; 1387 if (trigger_security_request){ 1388 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1389 sm_pairing_started(sm_connection); 1390 } 1391 break; 1392 #endif 1393 } 1394 #ifdef ENABLE_LE_CENTRAL 1395 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1396 sm_connection->sm_security_request_received = 0; 1397 sm_connection->sm_pairing_requested = 0; 1398 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1399 #endif 1400 break; 1401 1402 default: 1403 btstack_assert(false); 1404 break; 1405 } 1406 break; 1407 default: 1408 break; 1409 } 1410 1411 switch (event){ 1412 case ADDRESS_RESOLUTION_SUCCEEDED: 1413 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1414 break; 1415 case ADDRESS_RESOLUTION_FAILED: 1416 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1417 break; 1418 default: 1419 btstack_assert(false); 1420 break; 1421 } 1422 } 1423 1424 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1425 int le_db_index = -1; 1426 1427 // lookup device based on IRK 1428 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1429 int i; 1430 for (i=0; i < le_device_db_max_count(); i++){ 1431 sm_key_t irk; 1432 bd_addr_t address; 1433 int address_type = BD_ADDR_TYPE_UNKNOWN; 1434 le_device_db_info(i, &address_type, address, irk); 1435 // skip unused entries 1436 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1437 // compare Identity Address 1438 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1439 // compare Identity Resolving Key 1440 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1441 1442 log_info("sm: device found for IRK, updating"); 1443 le_db_index = i; 1444 break; 1445 } 1446 } else { 1447 // assert IRK is set to zero 1448 memset(setup->sm_peer_irk, 0, 16); 1449 } 1450 1451 // if not found, lookup via public address if possible 1452 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1453 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1454 int i; 1455 for (i=0; i < le_device_db_max_count(); i++){ 1456 bd_addr_t address; 1457 int address_type = BD_ADDR_TYPE_UNKNOWN; 1458 le_device_db_info(i, &address_type, address, NULL); 1459 // skip unused entries 1460 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1461 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1462 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1463 log_info("sm: device found for public address, updating"); 1464 le_db_index = i; 1465 break; 1466 } 1467 } 1468 } 1469 1470 // if not found, add to db 1471 bool new_to_le_device_db = false; 1472 if (le_db_index < 0) { 1473 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1474 new_to_le_device_db = true; 1475 } 1476 1477 if (le_db_index >= 0){ 1478 1479 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1480 if (!new_to_le_device_db){ 1481 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1482 } 1483 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1484 #else 1485 UNUSED(new_to_le_device_db); 1486 #endif 1487 1488 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1489 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1490 sm_conn->sm_le_db_index = le_db_index; 1491 1492 #ifdef ENABLE_LE_SIGNED_WRITE 1493 // store local CSRK 1494 setup->sm_le_device_index = le_db_index; 1495 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1496 log_info("sm: store local CSRK"); 1497 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1498 le_device_db_local_counter_set(le_db_index, 0); 1499 } 1500 1501 // store remote CSRK 1502 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1503 log_info("sm: store remote CSRK"); 1504 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1505 le_device_db_remote_counter_set(le_db_index, 0); 1506 } 1507 #endif 1508 // store encryption information for secure connections: LTK generated by ECDH 1509 if (setup->sm_use_secure_connections){ 1510 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1511 uint8_t zero_rand[8]; 1512 memset(zero_rand, 0, 8); 1513 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1514 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1515 } 1516 1517 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1518 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1519 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1520 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1521 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1522 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1523 1524 } 1525 } 1526 } 1527 1528 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1529 sm_conn->sm_pairing_failed_reason = reason; 1530 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1531 } 1532 1533 static int sm_lookup_by_address(void) { 1534 int i; 1535 for (i=0; i < le_device_db_max_count(); i++){ 1536 bd_addr_t address; 1537 int address_type = BD_ADDR_TYPE_UNKNOWN; 1538 le_device_db_info(i, &address_type, address, NULL); 1539 // skip unused entries 1540 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1541 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1542 return i; 1543 } 1544 } 1545 return -1; 1546 } 1547 1548 static void sm_remove_le_device_db_entry(uint16_t i) { 1549 le_device_db_remove(i); 1550 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1551 // to remove an entry from the resolving list requires its identity address, which was already deleted 1552 // fully reload resolving list instead 1553 gap_load_resolving_list_from_le_device_db(); 1554 #endif 1555 } 1556 1557 static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){ 1558 // if identity is provided, abort if we have bonding with same address but different irk 1559 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1560 int index = sm_lookup_by_address(); 1561 if (index >= 0){ 1562 sm_key_t irk; 1563 le_device_db_info(index, NULL, NULL, irk); 1564 if (memcmp(irk, setup->sm_peer_irk, 16) != 0){ 1565 // IRK doesn't match, delete bonding information 1566 log_info("New IRK for %s (type %u) does not match stored IRK -> delete bonding information", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); 1567 sm_remove_le_device_db_entry(index); 1568 } 1569 } 1570 } 1571 return 0; 1572 } 1573 1574 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1575 1576 // abort pairing if received keys are not valid 1577 uint8_t reason = sm_key_distribution_validate_received(sm_conn); 1578 if (reason != 0){ 1579 sm_pairing_error(sm_conn, reason); 1580 return; 1581 } 1582 1583 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1584 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1585 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1586 & SM_AUTHREQ_BONDING ) != 0u; 1587 1588 if (bonding_enabled){ 1589 sm_store_bonding_information(sm_conn); 1590 } else { 1591 log_info("Ignoring received keys, bonding not enabled"); 1592 } 1593 } 1594 1595 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1596 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1597 } 1598 1599 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1600 1601 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1602 static int sm_passkey_used(stk_generation_method_t method); 1603 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1604 1605 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1606 if (setup->sm_stk_generation_method == OOB){ 1607 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1608 } else { 1609 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); 1610 } 1611 } 1612 1613 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1614 if (IS_RESPONDER(sm_conn->sm_role)){ 1615 // Responder 1616 if (setup->sm_stk_generation_method == OOB){ 1617 // generate Nb 1618 log_info("Generate Nb"); 1619 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); 1620 } else { 1621 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1622 } 1623 } else { 1624 // Initiator role 1625 switch (setup->sm_stk_generation_method){ 1626 case JUST_WORKS: 1627 sm_sc_prepare_dhkey_check(sm_conn); 1628 break; 1629 1630 case NUMERIC_COMPARISON: 1631 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1632 break; 1633 case PK_INIT_INPUT: 1634 case PK_RESP_INPUT: 1635 case PK_BOTH_INPUT: 1636 if (setup->sm_passkey_bit < 20u) { 1637 sm_sc_start_calculating_local_confirm(sm_conn); 1638 } else { 1639 sm_sc_prepare_dhkey_check(sm_conn); 1640 } 1641 break; 1642 case OOB: 1643 sm_sc_prepare_dhkey_check(sm_conn); 1644 break; 1645 default: 1646 btstack_assert(false); 1647 break; 1648 } 1649 } 1650 } 1651 1652 static void sm_sc_cmac_done(uint8_t * hash){ 1653 log_info("sm_sc_cmac_done: "); 1654 log_info_hexdump(hash, 16); 1655 1656 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1657 sm_sc_oob_state = SM_SC_OOB_IDLE; 1658 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1659 return; 1660 } 1661 1662 sm_connection_t * sm_conn = sm_cmac_connection; 1663 sm_cmac_connection = NULL; 1664 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1665 link_key_type_t link_key_type; 1666 #endif 1667 1668 switch (sm_conn->sm_engine_state){ 1669 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1670 (void)memcpy(setup->sm_local_confirm, hash, 16); 1671 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1672 break; 1673 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1674 // check 1675 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1676 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1677 break; 1678 } 1679 sm_sc_state_after_receiving_random(sm_conn); 1680 break; 1681 case SM_SC_W4_CALCULATE_G2: { 1682 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1683 big_endian_store_32(setup->sm_tk, 12, vab); 1684 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1685 sm_trigger_user_response(sm_conn); 1686 break; 1687 } 1688 case SM_SC_W4_CALCULATE_F5_SALT: 1689 (void)memcpy(setup->sm_t, hash, 16); 1690 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1691 break; 1692 case SM_SC_W4_CALCULATE_F5_MACKEY: 1693 (void)memcpy(setup->sm_mackey, hash, 16); 1694 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1695 break; 1696 case SM_SC_W4_CALCULATE_F5_LTK: 1697 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1698 // Errata Service Release to the Bluetooth Specification: ESR09 1699 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1700 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1701 (void)memcpy(setup->sm_ltk, hash, 16); 1702 (void)memcpy(setup->sm_local_ltk, hash, 16); 1703 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1704 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1705 break; 1706 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1707 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1708 if (IS_RESPONDER(sm_conn->sm_role)){ 1709 // responder 1710 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1711 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1712 } else { 1713 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1714 } 1715 } else { 1716 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1717 } 1718 break; 1719 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1720 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1721 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1722 break; 1723 } 1724 if (IS_RESPONDER(sm_conn->sm_role)){ 1725 // responder 1726 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1727 } else { 1728 // initiator 1729 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1730 } 1731 break; 1732 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1733 case SM_SC_W4_CALCULATE_ILK: 1734 (void)memcpy(setup->sm_t, hash, 16); 1735 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1736 break; 1737 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1738 reverse_128(hash, setup->sm_t); 1739 link_key_type = sm_conn->sm_connection_authenticated ? 1740 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1741 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1742 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1743 if (IS_RESPONDER(sm_conn->sm_role)){ 1744 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1745 } else { 1746 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1747 } 1748 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1749 sm_done_for_handle(sm_conn->sm_handle); 1750 break; 1751 case SM_BR_EDR_W4_CALCULATE_ILK: 1752 (void)memcpy(setup->sm_t, hash, 16); 1753 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1754 break; 1755 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1756 log_info("Derived LE LTK from BR/EDR Link Key"); 1757 log_info_key("Link Key", hash); 1758 (void)memcpy(setup->sm_ltk, hash, 16); 1759 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1760 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1761 sm_store_bonding_information(sm_conn); 1762 sm_done_for_handle(sm_conn->sm_handle); 1763 break; 1764 #endif 1765 default: 1766 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1767 break; 1768 } 1769 sm_trigger_run(); 1770 } 1771 1772 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){ 1773 const uint16_t message_len = 65; 1774 sm_cmac_connection = sm_conn; 1775 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1776 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1777 sm_cmac_sc_buffer[64] = z; 1778 log_info("f4 key"); 1779 log_info_hexdump(x, 16); 1780 log_info("f4 message"); 1781 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1782 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1783 } 1784 1785 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1786 static const uint8_t f5_length[] = { 0x01, 0x00}; 1787 1788 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1789 1790 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1791 1792 log_info("f5_calculate_salt"); 1793 // calculate salt for f5 1794 const uint16_t message_len = 32; 1795 sm_cmac_connection = sm_conn; 1796 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1797 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1798 } 1799 1800 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){ 1801 const uint16_t message_len = 53; 1802 sm_cmac_connection = sm_conn; 1803 1804 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1805 sm_cmac_sc_buffer[0] = 0; 1806 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1807 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1808 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1809 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1810 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1811 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1812 log_info("f5 key"); 1813 log_info_hexdump(t, 16); 1814 log_info("f5 message for MacKey"); 1815 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1816 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1817 } 1818 1819 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1820 sm_key56_t bd_addr_master, bd_addr_slave; 1821 bd_addr_master[0] = setup->sm_m_addr_type; 1822 bd_addr_slave[0] = setup->sm_s_addr_type; 1823 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1824 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1825 if (IS_RESPONDER(sm_conn->sm_role)){ 1826 // responder 1827 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1828 } else { 1829 // initiator 1830 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1831 } 1832 } 1833 1834 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1835 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1836 const uint16_t message_len = 53; 1837 sm_cmac_connection = sm_conn; 1838 sm_cmac_sc_buffer[0] = 1; 1839 // 1..52 setup before 1840 log_info("f5 key"); 1841 log_info_hexdump(t, 16); 1842 log_info("f5 message for LTK"); 1843 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1844 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1845 } 1846 1847 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1848 f5_ltk(sm_conn, setup->sm_t); 1849 } 1850 1851 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){ 1852 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1853 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1854 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1855 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1856 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1857 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1858 } 1859 1860 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1861 const uint16_t message_len = 65; 1862 sm_cmac_connection = sm_conn; 1863 log_info("f6 key"); 1864 log_info_hexdump(w, 16); 1865 log_info("f6 message"); 1866 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1867 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1868 } 1869 1870 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1871 // - U is 256 bits 1872 // - V is 256 bits 1873 // - X is 128 bits 1874 // - Y is 128 bits 1875 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){ 1876 const uint16_t message_len = 80; 1877 sm_cmac_connection = sm_conn; 1878 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1879 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1880 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1881 log_info("g2 key"); 1882 log_info_hexdump(x, 16); 1883 log_info("g2 message"); 1884 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1885 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1886 } 1887 1888 static void g2_calculate(sm_connection_t * sm_conn) { 1889 // calc Va if numeric comparison 1890 if (IS_RESPONDER(sm_conn->sm_role)){ 1891 // responder 1892 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1893 } else { 1894 // initiator 1895 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1896 } 1897 } 1898 1899 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1900 uint8_t z = 0; 1901 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1902 // some form of passkey 1903 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1904 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1905 setup->sm_passkey_bit++; 1906 } 1907 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1908 } 1909 1910 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1911 // OOB 1912 if (setup->sm_stk_generation_method == OOB){ 1913 if (IS_RESPONDER(sm_conn->sm_role)){ 1914 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1915 } else { 1916 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1917 } 1918 return; 1919 } 1920 1921 uint8_t z = 0; 1922 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1923 // some form of passkey 1924 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1925 // sm_passkey_bit was increased before sending confirm value 1926 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1927 } 1928 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1929 } 1930 1931 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1932 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1933 1934 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1935 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1936 return; 1937 } else { 1938 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1939 } 1940 } 1941 1942 static void sm_sc_dhkey_calculated(void * arg){ 1943 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1944 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1945 if (sm_conn == NULL) return; 1946 1947 log_info("dhkey"); 1948 log_info_hexdump(&setup->sm_dhkey[0], 32); 1949 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1950 // trigger next step 1951 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1952 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1953 } 1954 sm_trigger_run(); 1955 } 1956 1957 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1958 // calculate DHKCheck 1959 sm_key56_t bd_addr_master, bd_addr_slave; 1960 bd_addr_master[0] = setup->sm_m_addr_type; 1961 bd_addr_slave[0] = setup->sm_s_addr_type; 1962 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1963 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1964 uint8_t iocap_a[3]; 1965 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1966 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1967 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1968 uint8_t iocap_b[3]; 1969 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1970 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1971 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1972 if (IS_RESPONDER(sm_conn->sm_role)){ 1973 // responder 1974 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1975 f6_engine(sm_conn, setup->sm_mackey); 1976 } else { 1977 // initiator 1978 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1979 f6_engine(sm_conn, setup->sm_mackey); 1980 } 1981 } 1982 1983 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1984 // validate E = f6() 1985 sm_key56_t bd_addr_master, bd_addr_slave; 1986 bd_addr_master[0] = setup->sm_m_addr_type; 1987 bd_addr_slave[0] = setup->sm_s_addr_type; 1988 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1989 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1990 1991 uint8_t iocap_a[3]; 1992 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1993 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1994 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1995 uint8_t iocap_b[3]; 1996 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1997 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1998 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1999 if (IS_RESPONDER(sm_conn->sm_role)){ 2000 // responder 2001 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2002 f6_engine(sm_conn, setup->sm_mackey); 2003 } else { 2004 // initiator 2005 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2006 f6_engine(sm_conn, setup->sm_mackey); 2007 } 2008 } 2009 2010 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2011 2012 // 2013 // Link Key Conversion Function h6 2014 // 2015 // h6(W, keyID) = AES-CMAC_W(keyID) 2016 // - W is 128 bits 2017 // - keyID is 32 bits 2018 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 2019 const uint16_t message_len = 4; 2020 sm_cmac_connection = sm_conn; 2021 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 2022 log_info("h6 key"); 2023 log_info_hexdump(w, 16); 2024 log_info("h6 message"); 2025 log_info_hexdump(sm_cmac_sc_buffer, message_len); 2026 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 2027 } 2028 // 2029 // Link Key Conversion Function h7 2030 // 2031 // h7(SALT, W) = AES-CMAC_SALT(W) 2032 // - SALT is 128 bits 2033 // - W is 128 bits 2034 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 2035 const uint16_t message_len = 16; 2036 sm_cmac_connection = sm_conn; 2037 log_info("h7 key"); 2038 log_info_hexdump(salt, 16); 2039 log_info("h7 message"); 2040 log_info_hexdump(w, 16); 2041 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 2042 } 2043 2044 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2045 // Errata Service Release to the Bluetooth Specification: ESR09 2046 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2047 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2048 2049 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2050 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2051 } 2052 2053 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2054 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2055 } 2056 2057 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2058 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2059 } 2060 2061 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2062 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2063 } 2064 2065 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2066 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2067 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2068 } 2069 2070 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2071 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2072 h7_engine(sm_conn, salt, setup->sm_link_key); 2073 } 2074 2075 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2076 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2077 btstack_assert(hci_connection != NULL); 2078 reverse_128(hci_connection->link_key, setup->sm_link_key); 2079 setup->sm_link_key_type = hci_connection->link_key_type; 2080 } 2081 2082 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2083 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; 2084 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2085 } 2086 2087 #endif 2088 2089 #endif 2090 2091 // key management legacy connections: 2092 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2093 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2094 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2095 // - responder reconnects: responder uses LTK receveived from master 2096 2097 // key management secure connections: 2098 // - both devices store same LTK from ECDH key exchange. 2099 2100 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2101 static void sm_load_security_info(sm_connection_t * sm_connection){ 2102 int encryption_key_size; 2103 int authenticated; 2104 int authorized; 2105 int secure_connection; 2106 2107 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2108 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2109 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2110 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); 2111 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2112 sm_connection->sm_connection_authenticated = authenticated; 2113 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2114 sm_connection->sm_connection_sc = secure_connection; 2115 } 2116 #endif 2117 2118 #ifdef ENABLE_LE_PERIPHERAL 2119 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2120 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2121 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2122 // re-establish used key encryption size 2123 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2124 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2125 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2126 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2127 // Legacy paring -> not SC 2128 sm_connection->sm_connection_sc = 0; 2129 log_info("sm: received ltk request with key size %u, authenticated %u", 2130 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2131 } 2132 #endif 2133 2134 // distributed key generation 2135 static bool sm_run_dpkg(void){ 2136 switch (dkg_state){ 2137 case DKG_CALC_IRK: 2138 // already busy? 2139 if (sm_aes128_state == SM_AES128_IDLE) { 2140 log_info("DKG_CALC_IRK started"); 2141 // IRK = d1(IR, 1, 0) 2142 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2143 sm_aes128_state = SM_AES128_ACTIVE; 2144 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2145 return true; 2146 } 2147 break; 2148 case DKG_CALC_DHK: 2149 // already busy? 2150 if (sm_aes128_state == SM_AES128_IDLE) { 2151 log_info("DKG_CALC_DHK started"); 2152 // DHK = d1(IR, 3, 0) 2153 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2154 sm_aes128_state = SM_AES128_ACTIVE; 2155 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2156 return true; 2157 } 2158 break; 2159 default: 2160 break; 2161 } 2162 return false; 2163 } 2164 2165 // random address updates 2166 static bool sm_run_rau(void){ 2167 switch (rau_state){ 2168 case RAU_GET_RANDOM: 2169 rau_state = RAU_W4_RANDOM; 2170 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2171 return true; 2172 case RAU_GET_ENC: 2173 // already busy? 2174 if (sm_aes128_state == SM_AES128_IDLE) { 2175 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2176 sm_aes128_state = SM_AES128_ACTIVE; 2177 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2178 return true; 2179 } 2180 break; 2181 default: 2182 break; 2183 } 2184 return false; 2185 } 2186 2187 // CSRK Lookup 2188 static bool sm_run_csrk(void){ 2189 btstack_linked_list_iterator_t it; 2190 2191 // -- if csrk lookup ready, find connection that require csrk lookup 2192 if (sm_address_resolution_idle()){ 2193 hci_connections_get_iterator(&it); 2194 while(btstack_linked_list_iterator_has_next(&it)){ 2195 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2196 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2197 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2198 // and start lookup 2199 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); 2200 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2201 break; 2202 } 2203 } 2204 } 2205 2206 // -- if csrk lookup ready, resolved addresses for received addresses 2207 if (sm_address_resolution_idle()) { 2208 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2209 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2210 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2211 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2212 btstack_memory_sm_lookup_entry_free(entry); 2213 } 2214 } 2215 2216 // -- Continue with device lookup by public or resolvable private address 2217 if (!sm_address_resolution_idle()){ 2218 while (sm_address_resolution_test < le_device_db_max_count()){ 2219 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2220 bd_addr_t addr; 2221 sm_key_t irk; 2222 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2223 2224 // skip unused entries 2225 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2226 sm_address_resolution_test++; 2227 continue; 2228 } 2229 2230 log_info("LE Device Lookup: device %u of %u", sm_address_resolution_test, le_device_db_max_count()); 2231 2232 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2233 log_info("LE Device Lookup: found by { addr_type, address} "); 2234 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2235 break; 2236 } 2237 2238 // if connection type is public, it must be a different one 2239 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2240 sm_address_resolution_test++; 2241 continue; 2242 } 2243 2244 // skip AH if no IRK 2245 if (sm_is_null_key(irk)){ 2246 sm_address_resolution_test++; 2247 continue; 2248 } 2249 2250 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2251 2252 log_info("LE Device Lookup: calculate AH"); 2253 log_info_key("IRK", irk); 2254 2255 (void)memcpy(sm_aes128_key, irk, 16); 2256 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2257 sm_aes128_state = SM_AES128_ACTIVE; 2258 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2259 return true; 2260 } 2261 2262 if (sm_address_resolution_test >= le_device_db_max_count()){ 2263 log_info("LE Device Lookup: not found"); 2264 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2265 } 2266 } 2267 return false; 2268 } 2269 2270 // SC OOB 2271 static bool sm_run_oob(void){ 2272 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2273 switch (sm_sc_oob_state){ 2274 case SM_SC_OOB_W2_CALC_CONFIRM: 2275 if (!sm_cmac_ready()) break; 2276 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2277 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2278 return true; 2279 default: 2280 break; 2281 } 2282 #endif 2283 return false; 2284 } 2285 2286 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2287 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2288 } 2289 2290 // handle basic actions that don't requires the full context 2291 static bool sm_run_basic(void){ 2292 btstack_linked_list_iterator_t it; 2293 hci_connections_get_iterator(&it); 2294 while(btstack_linked_list_iterator_has_next(&it)){ 2295 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2296 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2297 switch(sm_connection->sm_engine_state){ 2298 2299 // general 2300 case SM_GENERAL_SEND_PAIRING_FAILED: { 2301 uint8_t buffer[2]; 2302 buffer[0] = SM_CODE_PAIRING_FAILED; 2303 buffer[1] = sm_connection->sm_pairing_failed_reason; 2304 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2305 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2306 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2307 sm_done_for_handle(sm_connection->sm_handle); 2308 break; 2309 } 2310 2311 // responder side 2312 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2313 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2314 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2315 return true; 2316 2317 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2318 case SM_SC_RECEIVED_LTK_REQUEST: 2319 switch (sm_connection->sm_irk_lookup_state){ 2320 case IRK_LOOKUP_FAILED: 2321 log_info("LTK Request: IRK Lookup Failed)"); 2322 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2323 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2324 return true; 2325 default: 2326 break; 2327 } 2328 break; 2329 #endif 2330 default: 2331 break; 2332 } 2333 } 2334 return false; 2335 } 2336 2337 static void sm_run_activate_connection(void){ 2338 // Find connections that requires setup context and make active if no other is locked 2339 btstack_linked_list_iterator_t it; 2340 hci_connections_get_iterator(&it); 2341 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2342 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2343 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2344 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2345 bool done = true; 2346 int err; 2347 UNUSED(err); 2348 2349 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2350 // assert ec key is ready 2351 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2352 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2353 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2354 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2355 sm_ec_generate_new_key(); 2356 } 2357 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2358 continue; 2359 } 2360 } 2361 #endif 2362 2363 switch (sm_connection->sm_engine_state) { 2364 #ifdef ENABLE_LE_PERIPHERAL 2365 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2366 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2367 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2368 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2369 case SM_SC_RECEIVED_LTK_REQUEST: 2370 #endif 2371 #endif 2372 #ifdef ENABLE_LE_CENTRAL 2373 case SM_INITIATOR_PH4_HAS_LTK: 2374 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2375 #endif 2376 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2377 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2378 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2379 #endif 2380 // just lock context 2381 break; 2382 default: 2383 done = false; 2384 break; 2385 } 2386 if (done){ 2387 sm_active_connection_handle = sm_connection->sm_handle; 2388 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); 2389 } 2390 } 2391 } 2392 2393 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2394 int i; 2395 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2396 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2397 uint8_t action = 0; 2398 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2399 if (flags & (1u<<i)){ 2400 bool clear_flag = true; 2401 switch (i){ 2402 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2403 case SM_KEYPRESS_PASSKEY_CLEARED: 2404 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2405 default: 2406 break; 2407 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2408 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2409 num_actions--; 2410 clear_flag = num_actions == 0u; 2411 break; 2412 } 2413 if (clear_flag){ 2414 flags &= ~(1<<i); 2415 } 2416 action = i; 2417 break; 2418 } 2419 } 2420 setup->sm_keypress_notification = (num_actions << 5) | flags; 2421 2422 // send keypress notification 2423 uint8_t buffer[2]; 2424 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2425 buffer[1] = action; 2426 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2427 2428 // try 2429 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2430 } 2431 2432 static void sm_run_distribute_keys(sm_connection_t * connection){ 2433 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2434 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2435 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2436 uint8_t buffer[17]; 2437 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2438 reverse_128(setup->sm_ltk, &buffer[1]); 2439 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2440 sm_timeout_reset(connection); 2441 return; 2442 } 2443 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2444 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2445 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2446 uint8_t buffer[11]; 2447 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2448 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2449 reverse_64(setup->sm_local_rand, &buffer[3]); 2450 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2451 sm_timeout_reset(connection); 2452 return; 2453 } 2454 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2455 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2456 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2457 uint8_t buffer[17]; 2458 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2459 reverse_128(sm_persistent_irk, &buffer[1]); 2460 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2461 sm_timeout_reset(connection); 2462 return; 2463 } 2464 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2465 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2466 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2467 bd_addr_t local_address; 2468 uint8_t buffer[8]; 2469 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2470 switch (gap_random_address_get_mode()){ 2471 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2472 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2473 // public or static random 2474 gap_le_get_own_address(&buffer[1], local_address); 2475 break; 2476 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2477 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2478 // fallback to public 2479 gap_local_bd_addr(local_address); 2480 buffer[1] = 0; 2481 break; 2482 default: 2483 btstack_assert(false); 2484 break; 2485 } 2486 reverse_bd_addr(local_address, &buffer[2]); 2487 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2488 sm_timeout_reset(connection); 2489 return; 2490 } 2491 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2492 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2493 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2494 2495 #ifdef ENABLE_LE_SIGNED_WRITE 2496 // hack to reproduce test runs 2497 if (test_use_fixed_local_csrk){ 2498 memset(setup->sm_local_csrk, 0xcc, 16); 2499 } 2500 2501 // store local CSRK 2502 if (setup->sm_le_device_index >= 0){ 2503 log_info("sm: store local CSRK"); 2504 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2505 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2506 } 2507 #endif 2508 2509 uint8_t buffer[17]; 2510 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2511 reverse_128(setup->sm_local_csrk, &buffer[1]); 2512 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2513 sm_timeout_reset(connection); 2514 return; 2515 } 2516 btstack_assert(false); 2517 } 2518 2519 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2520 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2521 // requirements to derive link key from LE: 2522 // - use secure connections 2523 if (setup->sm_use_secure_connections == 0) return false; 2524 // - bonding needs to be enabled: 2525 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; 2526 if (!bonding_enabled) return false; 2527 // - need identity address / public addr 2528 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2529 if (!have_identity_address_info) return false; 2530 // - 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) 2531 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2532 // If SC is authenticated, we consider it safe to overwrite a stored key. 2533 // 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. 2534 uint8_t link_key[16]; 2535 link_key_type_t link_key_type; 2536 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2537 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2538 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2539 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2540 return false; 2541 } 2542 // get started (all of the above are true) 2543 return true; 2544 #else 2545 UNUSED(sm_connection); 2546 return false; 2547 #endif 2548 } 2549 2550 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2551 if (sm_ctkd_from_le(connection)){ 2552 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; 2553 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2554 } else { 2555 connection->sm_engine_state = SM_RESPONDER_IDLE; 2556 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2557 sm_done_for_handle(connection->sm_handle); 2558 } 2559 } 2560 2561 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2562 if (sm_ctkd_from_le(connection)){ 2563 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; 2564 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2565 } else { 2566 sm_master_pairing_success(connection); 2567 } 2568 } 2569 2570 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2571 static void sm_run_state_sc_send_confirmation(sm_connection_t *connection) { 2572 uint8_t buffer[17]; 2573 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2574 reverse_128(setup->sm_local_confirm, &buffer[1]); 2575 if (IS_RESPONDER(connection->sm_role)){ 2576 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2577 } else { 2578 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2579 } 2580 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2581 sm_timeout_reset(connection); 2582 } 2583 2584 static void sm_run_state_sc_send_pairing_random(sm_connection_t *connection) { 2585 uint8_t buffer[17]; 2586 buffer[0] = SM_CODE_PAIRING_RANDOM; 2587 reverse_128(setup->sm_local_nonce, &buffer[1]); 2588 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2589 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2590 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2591 if (IS_RESPONDER(connection->sm_role)){ 2592 // responder 2593 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2594 } else { 2595 // initiator 2596 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2597 } 2598 } else { 2599 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2600 if (IS_RESPONDER(connection->sm_role)){ 2601 // responder 2602 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2603 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2604 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2605 } else { 2606 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2607 sm_sc_prepare_dhkey_check(connection); 2608 } 2609 } else { 2610 // initiator 2611 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2612 } 2613 } 2614 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2615 sm_timeout_reset(connection); 2616 } 2617 2618 static void sm_run_state_sc_send_dhkey_check_command(sm_connection_t *connection) { 2619 uint8_t buffer[17]; 2620 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2621 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2622 2623 if (IS_RESPONDER(connection->sm_role)){ 2624 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2625 } else { 2626 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2627 } 2628 2629 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2630 sm_timeout_reset(connection); 2631 } 2632 2633 static void sm_run_state_sc_send_public_key_command(sm_connection_t *connection) { 2634 bool trigger_user_response = false; 2635 bool trigger_start_calculating_local_confirm = false; 2636 uint8_t buffer[65]; 2637 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2638 // 2639 reverse_256(&ec_q[0], &buffer[1]); 2640 reverse_256(&ec_q[32], &buffer[33]); 2641 2642 #ifdef ENABLE_TESTING_SUPPORT 2643 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2644 log_info("testing_support: invalidating public key"); 2645 // flip single bit of public key coordinate 2646 buffer[1] ^= 1; 2647 } 2648 #endif 2649 2650 // stk generation method 2651 // passkey entry: notify app to show passkey or to request passkey 2652 switch (setup->sm_stk_generation_method){ 2653 case JUST_WORKS: 2654 case NUMERIC_COMPARISON: 2655 if (IS_RESPONDER(connection->sm_role)){ 2656 // responder 2657 trigger_start_calculating_local_confirm = true; 2658 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2659 } else { 2660 // initiator 2661 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2662 } 2663 break; 2664 case PK_INIT_INPUT: 2665 case PK_RESP_INPUT: 2666 case PK_BOTH_INPUT: 2667 // use random TK for display 2668 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2669 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2670 setup->sm_passkey_bit = 0; 2671 2672 if (IS_RESPONDER(connection->sm_role)){ 2673 // responder 2674 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2675 } else { 2676 // initiator 2677 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2678 } 2679 trigger_user_response = true; 2680 break; 2681 case OOB: 2682 if (IS_RESPONDER(connection->sm_role)){ 2683 // responder 2684 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2685 } else { 2686 // initiator 2687 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2688 } 2689 break; 2690 default: 2691 btstack_assert(false); 2692 break; 2693 } 2694 2695 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2696 sm_timeout_reset(connection); 2697 2698 // trigger user response and calc confirm after sending pdu 2699 if (trigger_user_response){ 2700 sm_trigger_user_response(connection); 2701 } 2702 if (trigger_start_calculating_local_confirm){ 2703 sm_sc_start_calculating_local_confirm(connection); 2704 } 2705 } 2706 #endif 2707 2708 static bool sm_run_non_connection_logic(void){ 2709 bool done;; 2710 2711 done = sm_run_dpkg(); 2712 if (done) return true; 2713 2714 done = sm_run_rau(); 2715 if (done) return true; 2716 2717 done = sm_run_csrk(); 2718 if (done) return true; 2719 2720 done = sm_run_oob(); 2721 return done; 2722 } 2723 2724 static void sm_run(void){ 2725 2726 // assert that stack has already bootet 2727 if (hci_get_state() != HCI_STATE_WORKING) return; 2728 2729 // assert that we can send at least commands 2730 if (!hci_can_send_command_packet_now()) return; 2731 2732 // pause until IR/ER are ready 2733 if (sm_persistent_keys_random_active) return; 2734 2735 // non-connection related behaviour 2736 bool done = sm_run_non_connection_logic(); 2737 if (done) return; 2738 2739 // assert that we can send at least commands - cmd might have been sent by crypto engine 2740 if (!hci_can_send_command_packet_now()) return; 2741 2742 // handle basic actions that don't requires the full context 2743 done = sm_run_basic(); 2744 if (done) return; 2745 2746 // 2747 // active connection handling 2748 // -- use loop to handle next connection if lock on setup context is released 2749 2750 while (true) { 2751 2752 sm_run_activate_connection(); 2753 2754 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2755 2756 // 2757 // active connection handling 2758 // 2759 2760 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2761 if (!connection) { 2762 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2763 return; 2764 } 2765 2766 // assert that we could send a SM PDU - not needed for all of the following 2767 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2768 log_info("cannot send now, requesting can send now event"); 2769 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2770 return; 2771 } 2772 2773 // send keypress notifications 2774 if (setup->sm_keypress_notification){ 2775 sm_run_send_keypress_notification(connection); 2776 return; 2777 } 2778 2779 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2780 // assert that sm cmac engine is ready 2781 if (sm_cmac_ready() == false){ 2782 break; 2783 } 2784 #endif 2785 2786 int key_distribution_flags; 2787 UNUSED(key_distribution_flags); 2788 #ifdef ENABLE_LE_PERIPHERAL 2789 int err; 2790 bool have_ltk; 2791 uint8_t ltk[16]; 2792 #endif 2793 2794 log_info("sm_run: state %u", connection->sm_engine_state); 2795 switch (connection->sm_engine_state){ 2796 2797 // secure connections, initiator + responding states 2798 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2799 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2800 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2801 sm_sc_calculate_local_confirm(connection); 2802 break; 2803 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2804 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2805 sm_sc_calculate_remote_confirm(connection); 2806 break; 2807 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2808 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2809 sm_sc_calculate_f6_for_dhkey_check(connection); 2810 break; 2811 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2812 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2813 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2814 break; 2815 case SM_SC_W2_CALCULATE_F5_SALT: 2816 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2817 f5_calculate_salt(connection); 2818 break; 2819 case SM_SC_W2_CALCULATE_F5_MACKEY: 2820 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2821 f5_calculate_mackey(connection); 2822 break; 2823 case SM_SC_W2_CALCULATE_F5_LTK: 2824 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2825 f5_calculate_ltk(connection); 2826 break; 2827 case SM_SC_W2_CALCULATE_G2: 2828 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2829 g2_calculate(connection); 2830 break; 2831 #endif 2832 2833 #ifdef ENABLE_LE_CENTRAL 2834 // initiator side 2835 2836 case SM_INITIATOR_PH4_HAS_LTK: { 2837 sm_reset_setup(); 2838 sm_load_security_info(connection); 2839 2840 sm_key_t peer_ltk_flipped; 2841 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2842 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2843 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2844 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2845 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2846 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2847 2848 // notify after sending 2849 sm_reencryption_started(connection); 2850 return; 2851 } 2852 2853 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2854 sm_reset_setup(); 2855 sm_init_setup(connection); 2856 2857 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2858 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2859 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2860 sm_timeout_reset(connection); 2861 2862 // notify after sending 2863 sm_pairing_started(connection); 2864 break; 2865 #endif 2866 2867 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2868 case SM_SC_SEND_PUBLIC_KEY_COMMAND: 2869 sm_run_state_sc_send_public_key_command(connection); 2870 break; 2871 case SM_SC_SEND_CONFIRMATION: 2872 sm_run_state_sc_send_confirmation(connection); 2873 break; 2874 case SM_SC_SEND_PAIRING_RANDOM: 2875 sm_run_state_sc_send_pairing_random(connection); 2876 break; 2877 case SM_SC_SEND_DHKEY_CHECK_COMMAND: 2878 sm_run_state_sc_send_dhkey_check_command(connection); 2879 break; 2880 #endif 2881 2882 #ifdef ENABLE_LE_PERIPHERAL 2883 2884 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2885 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2886 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2887 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2888 sm_timeout_start(connection); 2889 break; 2890 } 2891 2892 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2893 case SM_SC_RECEIVED_LTK_REQUEST: 2894 switch (connection->sm_irk_lookup_state){ 2895 case IRK_LOOKUP_SUCCEEDED: 2896 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2897 // start using context by loading security info 2898 sm_reset_setup(); 2899 sm_load_security_info(connection); 2900 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2901 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2902 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2903 sm_reencryption_started(connection); 2904 sm_trigger_run(); 2905 break; 2906 } 2907 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2908 connection->sm_engine_state = SM_RESPONDER_IDLE; 2909 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2910 return; 2911 default: 2912 // just wait until IRK lookup is completed 2913 break; 2914 } 2915 break; 2916 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2917 2918 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2919 sm_reset_setup(); 2920 2921 // handle Pairing Request with LTK available 2922 switch (connection->sm_irk_lookup_state) { 2923 case IRK_LOOKUP_SUCCEEDED: 2924 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2925 have_ltk = !sm_is_null_key(ltk); 2926 if (have_ltk){ 2927 log_info("pairing request but LTK available"); 2928 // emit re-encryption start/fail sequence 2929 sm_reencryption_started(connection); 2930 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2931 } 2932 break; 2933 default: 2934 break; 2935 } 2936 2937 sm_init_setup(connection); 2938 2939 // recover pairing request 2940 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2941 err = sm_stk_generation_init(connection); 2942 2943 #ifdef ENABLE_TESTING_SUPPORT 2944 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2945 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2946 err = test_pairing_failure; 2947 } 2948 #endif 2949 if (err != 0){ 2950 // emit pairing started/failed sequence 2951 sm_pairing_started(connection); 2952 sm_pairing_error(connection, err); 2953 sm_trigger_run(); 2954 break; 2955 } 2956 2957 sm_timeout_start(connection); 2958 2959 // generate random number first, if we need to show passkey, otherwise send response 2960 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2961 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2962 break; 2963 } 2964 2965 /* fall through */ 2966 2967 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2968 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2969 2970 // start with initiator key dist flags 2971 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2972 2973 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2974 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2975 if (setup->sm_use_secure_connections){ 2976 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2977 } 2978 #endif 2979 // setup in response 2980 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); 2981 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); 2982 2983 // update key distribution after ENC was dropped 2984 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres), sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 2985 2986 if (setup->sm_use_secure_connections){ 2987 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2988 } else { 2989 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2990 } 2991 2992 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2993 sm_timeout_reset(connection); 2994 2995 // notify after sending 2996 sm_pairing_started(connection); 2997 2998 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2999 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 3000 sm_trigger_user_response(connection); 3001 } 3002 return; 3003 #endif 3004 3005 case SM_PH2_SEND_PAIRING_RANDOM: { 3006 uint8_t buffer[17]; 3007 buffer[0] = SM_CODE_PAIRING_RANDOM; 3008 reverse_128(setup->sm_local_random, &buffer[1]); 3009 if (IS_RESPONDER(connection->sm_role)){ 3010 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 3011 } else { 3012 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 3013 } 3014 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3015 sm_timeout_reset(connection); 3016 break; 3017 } 3018 3019 case SM_PH2_C1_GET_ENC_A: 3020 // already busy? 3021 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3022 // calculate confirm using aes128 engine - step 1 3023 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); 3024 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 3025 sm_aes128_state = SM_AES128_ACTIVE; 3026 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); 3027 break; 3028 3029 case SM_PH2_C1_GET_ENC_C: 3030 // already busy? 3031 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3032 // calculate m_confirm using aes128 engine - step 1 3033 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); 3034 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 3035 sm_aes128_state = SM_AES128_ACTIVE; 3036 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); 3037 break; 3038 3039 case SM_PH2_CALC_STK: 3040 // already busy? 3041 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3042 // calculate STK 3043 if (IS_RESPONDER(connection->sm_role)){ 3044 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 3045 } else { 3046 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3047 } 3048 connection->sm_engine_state = SM_PH2_W4_STK; 3049 sm_aes128_state = SM_AES128_ACTIVE; 3050 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); 3051 break; 3052 3053 case SM_PH3_Y_GET_ENC: 3054 // already busy? 3055 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3056 // PH3B2 - calculate Y from - enc 3057 3058 // dm helper (was sm_dm_r_prime) 3059 // r' = padding || r 3060 // r - 64 bit value 3061 memset(&sm_aes128_plaintext[0], 0, 8); 3062 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3063 3064 // Y = dm(DHK, Rand) 3065 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3066 sm_aes128_state = SM_AES128_ACTIVE; 3067 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); 3068 break; 3069 3070 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3071 uint8_t buffer[17]; 3072 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3073 reverse_128(setup->sm_local_confirm, &buffer[1]); 3074 if (IS_RESPONDER(connection->sm_role)){ 3075 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3076 } else { 3077 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3078 } 3079 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3080 sm_timeout_reset(connection); 3081 return; 3082 } 3083 #ifdef ENABLE_LE_PERIPHERAL 3084 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3085 // cache key before using 3086 sm_cache_ltk(connection, setup->sm_ltk); 3087 sm_key_t stk_flipped; 3088 reverse_128(setup->sm_ltk, stk_flipped); 3089 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3090 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3091 return; 3092 } 3093 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3094 // allow to override LTK 3095 if (sm_get_ltk_callback != NULL){ 3096 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3097 } 3098 // cache key before using 3099 sm_cache_ltk(connection, setup->sm_ltk); 3100 sm_key_t ltk_flipped; 3101 reverse_128(setup->sm_ltk, ltk_flipped); 3102 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3103 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3104 return; 3105 } 3106 3107 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3108 // already busy? 3109 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3110 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3111 3112 sm_reset_setup(); 3113 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3114 3115 sm_reencryption_started(connection); 3116 3117 // dm helper (was sm_dm_r_prime) 3118 // r' = padding || r 3119 // r - 64 bit value 3120 memset(&sm_aes128_plaintext[0], 0, 8); 3121 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3122 3123 // Y = dm(DHK, Rand) 3124 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3125 sm_aes128_state = SM_AES128_ACTIVE; 3126 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); 3127 return; 3128 #endif 3129 #ifdef ENABLE_LE_CENTRAL 3130 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3131 sm_key_t stk_flipped; 3132 reverse_128(setup->sm_ltk, stk_flipped); 3133 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3134 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3135 return; 3136 } 3137 #endif 3138 3139 case SM_PH3_DISTRIBUTE_KEYS: 3140 // send next key 3141 if (setup->sm_key_distribution_send_set != 0){ 3142 sm_run_distribute_keys(connection); 3143 } 3144 3145 // more to send? 3146 if (setup->sm_key_distribution_send_set != 0){ 3147 return; 3148 } 3149 3150 // keys are sent 3151 if (IS_RESPONDER(connection->sm_role)){ 3152 // slave -> receive master keys if any 3153 if (sm_key_distribution_all_received()){ 3154 sm_key_distribution_handle_all_received(connection); 3155 sm_key_distribution_complete_responder(connection); 3156 // start CTKD right away 3157 continue; 3158 } else { 3159 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3160 } 3161 } else { 3162 sm_master_pairing_success(connection); 3163 } 3164 break; 3165 3166 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3167 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3168 // fill in sm setup (lite version of sm_init_setup) 3169 sm_reset_setup(); 3170 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3171 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3172 setup->sm_s_addr_type = connection->sm_own_addr_type; 3173 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3174 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3175 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3176 setup->sm_use_secure_connections = true; 3177 sm_ctkd_fetch_br_edr_link_key(connection); 3178 3179 // Enc Key and IRK if requested 3180 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3181 #ifdef ENABLE_LE_SIGNED_WRITE 3182 // Plus signing key if supported 3183 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3184 #endif 3185 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3186 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3187 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3188 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3189 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3190 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3191 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3192 3193 // set state and send pairing response 3194 sm_timeout_start(connection); 3195 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3196 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3197 break; 3198 3199 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3200 // fill in sm setup (lite version of sm_init_setup) 3201 sm_reset_setup(); 3202 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3203 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3204 setup->sm_s_addr_type = connection->sm_own_addr_type; 3205 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3206 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3207 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3208 setup->sm_use_secure_connections = true; 3209 sm_ctkd_fetch_br_edr_link_key(connection); 3210 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3211 3212 // Enc Key and IRK if requested 3213 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3214 #ifdef ENABLE_LE_SIGNED_WRITE 3215 // Plus signing key if supported 3216 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3217 #endif 3218 // drop flags not requested by initiator 3219 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3220 3221 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3222 // - the IO Capability field, 3223 // - the OOB data flag field, and 3224 // - all bits in the Auth Req field except the CT2 bit. 3225 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3226 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3227 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3228 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3229 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3230 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3231 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3232 3233 // configure key distribution, LTK is derived locally 3234 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3235 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3236 3237 // set state and send pairing response 3238 sm_timeout_start(connection); 3239 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3240 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3241 break; 3242 case SM_BR_EDR_DISTRIBUTE_KEYS: 3243 if (setup->sm_key_distribution_send_set != 0) { 3244 sm_run_distribute_keys(connection); 3245 return; 3246 } 3247 // keys are sent 3248 if (IS_RESPONDER(connection->sm_role)) { 3249 // responder -> receive master keys if there are any 3250 if (!sm_key_distribution_all_received()){ 3251 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3252 break; 3253 } 3254 } 3255 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3256 sm_ctkd_start_from_br_edr(connection); 3257 continue; 3258 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3259 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3260 h6_calculate_ilk_from_le_ltk(connection); 3261 break; 3262 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3263 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3264 h6_calculate_br_edr_link_key(connection); 3265 break; 3266 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3267 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3268 h7_calculate_ilk_from_le_ltk(connection); 3269 break; 3270 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3271 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3272 h6_calculate_ilk_from_br_edr(connection); 3273 break; 3274 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3275 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3276 h6_calculate_le_ltk(connection); 3277 break; 3278 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3279 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3280 h7_calculate_ilk_from_br_edr(connection); 3281 break; 3282 #endif 3283 3284 default: 3285 break; 3286 } 3287 3288 // check again if active connection was released 3289 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3290 } 3291 } 3292 3293 // sm_aes128_state stays active 3294 static void sm_handle_encryption_result_enc_a(void *arg){ 3295 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3296 sm_aes128_state = SM_AES128_IDLE; 3297 3298 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3299 if (connection == NULL) return; 3300 3301 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3302 sm_aes128_state = SM_AES128_ACTIVE; 3303 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); 3304 } 3305 3306 static void sm_handle_encryption_result_enc_b(void *arg){ 3307 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3308 sm_aes128_state = SM_AES128_IDLE; 3309 3310 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3311 if (connection == NULL) return; 3312 3313 log_info_key("c1!", setup->sm_local_confirm); 3314 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3315 sm_trigger_run(); 3316 } 3317 3318 // sm_aes128_state stays active 3319 static void sm_handle_encryption_result_enc_c(void *arg){ 3320 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3321 sm_aes128_state = SM_AES128_IDLE; 3322 3323 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3324 if (connection == NULL) return; 3325 3326 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3327 sm_aes128_state = SM_AES128_ACTIVE; 3328 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); 3329 } 3330 3331 static void sm_handle_encryption_result_enc_d(void * arg){ 3332 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3333 sm_aes128_state = SM_AES128_IDLE; 3334 3335 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3336 if (connection == NULL) return; 3337 3338 log_info_key("c1!", sm_aes128_ciphertext); 3339 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3340 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3341 sm_trigger_run(); 3342 return; 3343 } 3344 if (IS_RESPONDER(connection->sm_role)){ 3345 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3346 sm_trigger_run(); 3347 } else { 3348 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3349 sm_aes128_state = SM_AES128_ACTIVE; 3350 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); 3351 } 3352 } 3353 3354 static void sm_handle_encryption_result_enc_stk(void *arg){ 3355 sm_aes128_state = SM_AES128_IDLE; 3356 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3357 3358 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3359 if (connection == NULL) return; 3360 3361 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3362 log_info_key("stk", setup->sm_ltk); 3363 if (IS_RESPONDER(connection->sm_role)){ 3364 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3365 } else { 3366 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3367 } 3368 sm_trigger_run(); 3369 } 3370 3371 // sm_aes128_state stays active 3372 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3373 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3374 sm_aes128_state = SM_AES128_IDLE; 3375 3376 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3377 if (connection == NULL) return; 3378 3379 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3380 log_info_hex16("y", setup->sm_local_y); 3381 // PH3B3 - calculate EDIV 3382 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3383 log_info_hex16("ediv", setup->sm_local_ediv); 3384 // PH3B4 - calculate LTK - enc 3385 // LTK = d1(ER, DIV, 0)) 3386 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3387 sm_aes128_state = SM_AES128_ACTIVE; 3388 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); 3389 } 3390 3391 #ifdef ENABLE_LE_PERIPHERAL 3392 // sm_aes128_state stays active 3393 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3394 sm_aes128_state = SM_AES128_IDLE; 3395 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3396 3397 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3398 if (connection == NULL) return; 3399 3400 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3401 log_info_hex16("y", setup->sm_local_y); 3402 3403 // PH3B3 - calculate DIV 3404 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3405 log_info_hex16("ediv", setup->sm_local_ediv); 3406 // PH3B4 - calculate LTK - enc 3407 // LTK = d1(ER, DIV, 0)) 3408 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3409 sm_aes128_state = SM_AES128_ACTIVE; 3410 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); 3411 } 3412 #endif 3413 3414 // sm_aes128_state stays active 3415 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3416 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3417 sm_aes128_state = SM_AES128_IDLE; 3418 3419 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3420 if (connection == NULL) return; 3421 3422 log_info_key("ltk", setup->sm_ltk); 3423 // calc CSRK next 3424 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3425 sm_aes128_state = SM_AES128_ACTIVE; 3426 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); 3427 } 3428 3429 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3430 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3431 sm_aes128_state = SM_AES128_IDLE; 3432 3433 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3434 if (connection == NULL) return; 3435 3436 sm_aes128_state = SM_AES128_IDLE; 3437 log_info_key("csrk", setup->sm_local_csrk); 3438 if (setup->sm_key_distribution_send_set){ 3439 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3440 } else { 3441 // no keys to send, just continue 3442 if (IS_RESPONDER(connection->sm_role)){ 3443 if (sm_key_distribution_all_received()){ 3444 sm_key_distribution_handle_all_received(connection); 3445 sm_key_distribution_complete_responder(connection); 3446 } else { 3447 // slave -> receive master keys 3448 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3449 } 3450 } else { 3451 sm_key_distribution_complete_initiator(connection); 3452 } 3453 } 3454 sm_trigger_run(); 3455 } 3456 3457 #ifdef ENABLE_LE_PERIPHERAL 3458 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3459 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3460 sm_aes128_state = SM_AES128_IDLE; 3461 3462 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3463 if (connection == NULL) return; 3464 3465 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3466 log_info_key("ltk", setup->sm_ltk); 3467 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3468 sm_trigger_run(); 3469 } 3470 #endif 3471 3472 static void sm_handle_encryption_result_address_resolution(void *arg){ 3473 UNUSED(arg); 3474 sm_aes128_state = SM_AES128_IDLE; 3475 3476 // compare calulated address against connecting device 3477 uint8_t * hash = &sm_aes128_ciphertext[13]; 3478 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3479 log_info("LE Device Lookup: matched resolvable private address"); 3480 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3481 sm_trigger_run(); 3482 return; 3483 } 3484 // no match, try next 3485 sm_address_resolution_test++; 3486 sm_trigger_run(); 3487 } 3488 3489 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3490 UNUSED(arg); 3491 sm_aes128_state = SM_AES128_IDLE; 3492 3493 log_info_key("irk", sm_persistent_irk); 3494 dkg_state = DKG_CALC_DHK; 3495 sm_trigger_run(); 3496 } 3497 3498 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3499 UNUSED(arg); 3500 sm_aes128_state = SM_AES128_IDLE; 3501 3502 log_info_key("dhk", sm_persistent_dhk); 3503 dkg_state = DKG_READY; 3504 sm_trigger_run(); 3505 } 3506 3507 static void sm_handle_encryption_result_rau(void *arg){ 3508 UNUSED(arg); 3509 sm_aes128_state = SM_AES128_IDLE; 3510 3511 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3512 rau_state = RAU_IDLE; 3513 hci_le_random_address_set(sm_random_address); 3514 3515 sm_trigger_run(); 3516 } 3517 3518 static void sm_handle_random_result_rau(void * arg){ 3519 UNUSED(arg); 3520 // non-resolvable vs. resolvable 3521 switch (gap_random_adress_type){ 3522 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3523 // resolvable: use random as prand and calc address hash 3524 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3525 sm_random_address[0u] &= 0x3fu; 3526 sm_random_address[0u] |= 0x40u; 3527 rau_state = RAU_GET_ENC; 3528 break; 3529 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3530 default: 3531 // "The two most significant bits of the address shall be equal to ‘0’"" 3532 sm_random_address[0u] &= 0x3fu; 3533 rau_state = RAU_IDLE; 3534 hci_le_random_address_set(sm_random_address); 3535 break; 3536 } 3537 sm_trigger_run(); 3538 } 3539 3540 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3541 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3542 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3543 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3544 if (connection == NULL) return; 3545 3546 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3547 sm_trigger_run(); 3548 } 3549 3550 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3551 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3552 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3553 if (connection == NULL) return; 3554 3555 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3556 sm_trigger_run(); 3557 } 3558 #endif 3559 3560 static void sm_handle_random_result_ph2_random(void * arg){ 3561 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3562 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3563 if (connection == NULL) return; 3564 3565 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3566 sm_trigger_run(); 3567 } 3568 3569 static void sm_handle_random_result_ph2_tk(void * arg){ 3570 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3571 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3572 if (connection == NULL) return; 3573 3574 sm_reset_tk(); 3575 uint32_t tk; 3576 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3577 // map random to 0-999999 without speding much cycles on a modulus operation 3578 tk = little_endian_read_32(sm_random_data,0); 3579 tk = tk & 0xfffff; // 1048575 3580 if (tk >= 999999u){ 3581 tk = tk - 999999u; 3582 } 3583 } else { 3584 // override with pre-defined passkey 3585 tk = sm_fixed_passkey_in_display_role; 3586 } 3587 big_endian_store_32(setup->sm_tk, 12, tk); 3588 if (IS_RESPONDER(connection->sm_role)){ 3589 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3590 } else { 3591 if (setup->sm_use_secure_connections){ 3592 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3593 } else { 3594 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3595 sm_trigger_user_response(connection); 3596 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3597 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3598 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); 3599 } 3600 } 3601 } 3602 sm_trigger_run(); 3603 } 3604 3605 static void sm_handle_random_result_ph3_div(void * arg){ 3606 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3607 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3608 if (connection == NULL) return; 3609 3610 // use 16 bit from random value as div 3611 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3612 log_info_hex16("div", setup->sm_local_div); 3613 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3614 sm_trigger_run(); 3615 } 3616 3617 static void sm_handle_random_result_ph3_random(void * arg){ 3618 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3619 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3620 if (connection == NULL) return; 3621 3622 reverse_64(sm_random_data, setup->sm_local_rand); 3623 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3624 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3625 // no db for authenticated flag hack: store flag in bit 4 of LSB 3626 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3627 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3628 } 3629 static void sm_validate_er_ir(void){ 3630 // warn about default ER/IR 3631 bool warning = false; 3632 if (sm_ir_is_default()){ 3633 warning = true; 3634 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3635 } 3636 if (sm_er_is_default()){ 3637 warning = true; 3638 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3639 } 3640 if (warning) { 3641 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3642 } 3643 } 3644 3645 static void sm_handle_random_result_ir(void *arg){ 3646 sm_persistent_keys_random_active = false; 3647 if (arg != NULL){ 3648 // key generated, store in tlv 3649 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3650 log_info("Generated IR key. Store in TLV status: %d", status); 3651 UNUSED(status); 3652 } 3653 log_info_key("IR", sm_persistent_ir); 3654 dkg_state = DKG_CALC_IRK; 3655 3656 if (test_use_fixed_local_irk){ 3657 log_info_key("IRK", sm_persistent_irk); 3658 dkg_state = DKG_CALC_DHK; 3659 } 3660 3661 sm_trigger_run(); 3662 } 3663 3664 static void sm_handle_random_result_er(void *arg){ 3665 sm_persistent_keys_random_active = false; 3666 if (arg != 0){ 3667 // key generated, store in tlv 3668 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3669 log_info("Generated ER key. Store in TLV status: %d", status); 3670 UNUSED(status); 3671 } 3672 log_info_key("ER", sm_persistent_er); 3673 3674 // try load ir 3675 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3676 if (key_size == 16){ 3677 // ok, let's continue 3678 log_info("IR from TLV"); 3679 sm_handle_random_result_ir( NULL ); 3680 } else { 3681 // invalid, generate new random one 3682 sm_persistent_keys_random_active = true; 3683 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3684 } 3685 } 3686 3687 static void sm_connection_init(sm_connection_t * sm_conn, hci_con_handle_t con_handle, uint8_t role, uint8_t addr_type, bd_addr_t address){ 3688 3689 // connection info 3690 sm_conn->sm_handle = con_handle; 3691 sm_conn->sm_role = role; 3692 sm_conn->sm_peer_addr_type = addr_type; 3693 memcpy(sm_conn->sm_peer_address, address, 6); 3694 3695 // security properties 3696 sm_conn->sm_connection_encrypted = 0; 3697 sm_conn->sm_connection_authenticated = 0; 3698 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3699 sm_conn->sm_le_db_index = -1; 3700 sm_conn->sm_reencryption_active = false; 3701 3702 // prepare CSRK lookup (does not involve setup) 3703 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3704 3705 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3706 } 3707 3708 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3709 3710 UNUSED(channel); // ok: there is no channel 3711 UNUSED(size); // ok: fixed format HCI events 3712 3713 sm_connection_t * sm_conn; 3714 hci_con_handle_t con_handle; 3715 uint8_t status; 3716 bd_addr_t addr; 3717 3718 switch (packet_type) { 3719 3720 case HCI_EVENT_PACKET: 3721 switch (hci_event_packet_get_type(packet)) { 3722 3723 case BTSTACK_EVENT_STATE: 3724 switch (btstack_event_state_get_state(packet)){ 3725 case HCI_STATE_WORKING: 3726 log_info("HCI Working!"); 3727 // setup IR/ER with TLV 3728 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3729 if (sm_tlv_impl != NULL){ 3730 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3731 if (key_size == 16){ 3732 // ok, let's continue 3733 log_info("ER from TLV"); 3734 sm_handle_random_result_er( NULL ); 3735 } else { 3736 // invalid, generate random one 3737 sm_persistent_keys_random_active = true; 3738 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3739 } 3740 } else { 3741 sm_validate_er_ir(); 3742 dkg_state = DKG_CALC_IRK; 3743 3744 if (test_use_fixed_local_irk){ 3745 log_info_key("IRK", sm_persistent_irk); 3746 dkg_state = DKG_CALC_DHK; 3747 } 3748 } 3749 3750 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3751 // trigger ECC key generation 3752 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3753 sm_ec_generate_new_key(); 3754 } 3755 #endif 3756 3757 // restart random address updates after power cycle 3758 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ 3759 gap_random_address_set(sm_random_address); 3760 } else { 3761 gap_random_address_set_mode(gap_random_adress_type); 3762 } 3763 break; 3764 3765 case HCI_STATE_OFF: 3766 case HCI_STATE_HALTING: 3767 log_info("SM: reset state"); 3768 // stop random address update 3769 gap_random_address_update_stop(); 3770 // reset state 3771 sm_state_reset(); 3772 break; 3773 3774 default: 3775 break; 3776 } 3777 break; 3778 3779 #ifdef ENABLE_CLASSIC 3780 case HCI_EVENT_CONNECTION_COMPLETE: 3781 // ignore if connection failed 3782 if (hci_event_connection_complete_get_status(packet)) return; 3783 3784 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3785 sm_conn = sm_get_connection_for_handle(con_handle); 3786 if (!sm_conn) break; 3787 3788 hci_event_connection_complete_get_bd_addr(packet, addr); 3789 sm_connection_init(sm_conn, 3790 con_handle, 3791 (uint8_t) gap_get_role(con_handle), 3792 BD_ADDR_TYPE_LE_PUBLIC, 3793 addr); 3794 // classic connection corresponds to public le address 3795 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3796 gap_local_bd_addr(sm_conn->sm_own_address); 3797 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3798 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3799 break; 3800 #endif 3801 3802 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3803 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3804 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3805 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3806 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3807 if (sm_conn == NULL) break; 3808 sm_conn->sm_pairing_requested = 1; 3809 break; 3810 #endif 3811 3812 case HCI_EVENT_LE_META: 3813 switch (packet[2]) { 3814 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3815 // ignore if connection failed 3816 if (packet[3]) return; 3817 3818 con_handle = little_endian_read_16(packet, 4); 3819 sm_conn = sm_get_connection_for_handle(con_handle); 3820 if (!sm_conn) break; 3821 3822 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3823 sm_connection_init(sm_conn, 3824 con_handle, 3825 hci_subevent_le_connection_complete_get_role(packet), 3826 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3827 addr); 3828 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3829 3830 // track our addr used for this connection and set state 3831 #ifdef ENABLE_LE_PERIPHERAL 3832 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3833 // responder - use own address from advertisements 3834 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3835 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3836 } 3837 #endif 3838 #ifdef ENABLE_LE_CENTRAL 3839 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3840 // initiator - use own address from create connection 3841 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3842 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3843 } 3844 #endif 3845 break; 3846 3847 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3848 con_handle = little_endian_read_16(packet, 3); 3849 sm_conn = sm_get_connection_for_handle(con_handle); 3850 if (!sm_conn) break; 3851 3852 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3853 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3854 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3855 break; 3856 } 3857 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3858 // PH2 SEND LTK as we need to exchange keys in PH3 3859 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3860 break; 3861 } 3862 3863 // store rand and ediv 3864 reverse_64(&packet[5], sm_conn->sm_local_rand); 3865 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3866 3867 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3868 // potentially stored LTK is from the master 3869 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3870 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3871 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3872 break; 3873 } 3874 // additionally check if remote is in LE Device DB if requested 3875 switch(sm_conn->sm_irk_lookup_state){ 3876 case IRK_LOOKUP_FAILED: 3877 log_info("LTK Request: device not in device db"); 3878 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3879 break; 3880 case IRK_LOOKUP_SUCCEEDED: 3881 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3882 break; 3883 default: 3884 // wait for irk look doen 3885 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3886 break; 3887 } 3888 break; 3889 } 3890 3891 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3892 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3893 #else 3894 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3895 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3896 #endif 3897 break; 3898 3899 default: 3900 break; 3901 } 3902 break; 3903 3904 case HCI_EVENT_ENCRYPTION_CHANGE: 3905 case HCI_EVENT_ENCRYPTION_CHANGE_V2: 3906 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3907 sm_conn = sm_get_connection_for_handle(con_handle); 3908 if (!sm_conn) break; 3909 3910 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3911 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3912 sm_conn->sm_actual_encryption_key_size); 3913 log_info("event handler, state %u", sm_conn->sm_engine_state); 3914 3915 switch (sm_conn->sm_engine_state){ 3916 3917 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3918 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3919 if (sm_conn->sm_connection_encrypted) { 3920 status = ERROR_CODE_SUCCESS; 3921 if (sm_conn->sm_role){ 3922 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3923 } else { 3924 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3925 } 3926 } else { 3927 status = hci_event_encryption_change_get_status(packet); 3928 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3929 // also, gap_reconnect_security_setup_active will return true 3930 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3931 } 3932 3933 // emit re-encryption complete 3934 sm_reencryption_complete(sm_conn, status); 3935 3936 // notify client, if pairing was requested before 3937 if (sm_conn->sm_pairing_requested){ 3938 sm_conn->sm_pairing_requested = 0; 3939 sm_pairing_complete(sm_conn, status, 0); 3940 } 3941 3942 sm_done_for_handle(sm_conn->sm_handle); 3943 break; 3944 3945 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3946 if (!sm_conn->sm_connection_encrypted) break; 3947 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3948 if (IS_RESPONDER(sm_conn->sm_role)){ 3949 // slave 3950 if (setup->sm_use_secure_connections){ 3951 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3952 } else { 3953 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); 3954 } 3955 } else { 3956 // master 3957 if (sm_key_distribution_all_received()){ 3958 // skip receiving keys as there are none 3959 sm_key_distribution_handle_all_received(sm_conn); 3960 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); 3961 } else { 3962 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3963 } 3964 } 3965 break; 3966 3967 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3968 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3969 // CTKD requires BR/EDR Secure Connection 3970 if (sm_conn->sm_connection_encrypted != 2) break; 3971 // prepare for pairing request 3972 if (IS_RESPONDER(sm_conn->sm_role)){ 3973 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3974 } else if (sm_conn->sm_pairing_requested){ 3975 // check if remote supports fixed channels 3976 bool defer = true; 3977 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 3978 if (hci_connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE){ 3979 // check if remote supports SMP over BR/EDR 3980 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 3981 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3982 } else { 3983 defer = false; 3984 } 3985 } else { 3986 // wait for fixed channel info 3987 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK; 3988 } 3989 if (defer){ 3990 hci_dedicated_bonding_defer_disconnect(con_handle, true); 3991 } 3992 } 3993 break; 3994 #endif 3995 default: 3996 break; 3997 } 3998 break; 3999 4000 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 4001 con_handle = little_endian_read_16(packet, 3); 4002 sm_conn = sm_get_connection_for_handle(con_handle); 4003 if (!sm_conn) break; 4004 4005 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 4006 log_info("event handler, state %u", sm_conn->sm_engine_state); 4007 // continue if part of initial pairing 4008 switch (sm_conn->sm_engine_state){ 4009 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4010 if (sm_conn->sm_role){ 4011 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4012 } else { 4013 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4014 } 4015 sm_done_for_handle(sm_conn->sm_handle); 4016 break; 4017 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4018 if (IS_RESPONDER(sm_conn->sm_role)){ 4019 // slave 4020 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); 4021 } else { 4022 // master 4023 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 4024 } 4025 break; 4026 default: 4027 break; 4028 } 4029 break; 4030 4031 4032 case HCI_EVENT_DISCONNECTION_COMPLETE: 4033 con_handle = little_endian_read_16(packet, 3); 4034 sm_done_for_handle(con_handle); 4035 sm_conn = sm_get_connection_for_handle(con_handle); 4036 if (!sm_conn) break; 4037 4038 // pairing failed, if it was ongoing 4039 switch (sm_conn->sm_engine_state){ 4040 case SM_GENERAL_IDLE: 4041 case SM_INITIATOR_CONNECTED: 4042 case SM_RESPONDER_IDLE: 4043 break; 4044 default: 4045 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 4046 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 4047 break; 4048 } 4049 4050 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 4051 sm_conn->sm_handle = 0; 4052 break; 4053 4054 case HCI_EVENT_COMMAND_COMPLETE: 4055 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 4056 // set local addr for le device db 4057 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 4058 le_device_db_set_local_bd_addr(addr); 4059 } 4060 break; 4061 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4062 case L2CAP_EVENT_INFORMATION_RESPONSE: 4063 con_handle = l2cap_event_information_response_get_con_handle(packet); 4064 sm_conn = sm_get_connection_for_handle(con_handle); 4065 if (!sm_conn) break; 4066 if (sm_conn->sm_engine_state == SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK){ 4067 // check if remote supports SMP over BR/EDR 4068 const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 4069 if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ 4070 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 4071 } else { 4072 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 4073 hci_dedicated_bonding_defer_disconnect(con_handle, false); 4074 } 4075 } 4076 break; 4077 #endif 4078 default: 4079 break; 4080 } 4081 break; 4082 default: 4083 break; 4084 } 4085 4086 sm_run(); 4087 } 4088 4089 static inline int sm_calc_actual_encryption_key_size(int other){ 4090 if (other < sm_min_encryption_key_size) return 0; 4091 if (other < sm_max_encryption_key_size) return other; 4092 return sm_max_encryption_key_size; 4093 } 4094 4095 4096 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4097 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 4098 switch (method){ 4099 case JUST_WORKS: 4100 case NUMERIC_COMPARISON: 4101 return 1; 4102 default: 4103 return 0; 4104 } 4105 } 4106 // responder 4107 4108 static int sm_passkey_used(stk_generation_method_t method){ 4109 switch (method){ 4110 case PK_RESP_INPUT: 4111 return 1; 4112 default: 4113 return 0; 4114 } 4115 } 4116 4117 static int sm_passkey_entry(stk_generation_method_t method){ 4118 switch (method){ 4119 case PK_RESP_INPUT: 4120 case PK_INIT_INPUT: 4121 case PK_BOTH_INPUT: 4122 return 1; 4123 default: 4124 return 0; 4125 } 4126 } 4127 4128 #endif 4129 4130 /** 4131 * @return ok 4132 */ 4133 static int sm_validate_stk_generation_method(void){ 4134 // check if STK generation method is acceptable by client 4135 switch (setup->sm_stk_generation_method){ 4136 case JUST_WORKS: 4137 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4138 case PK_RESP_INPUT: 4139 case PK_INIT_INPUT: 4140 case PK_BOTH_INPUT: 4141 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4142 case OOB: 4143 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4144 case NUMERIC_COMPARISON: 4145 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4146 default: 4147 return 0; 4148 } 4149 } 4150 4151 #ifdef ENABLE_LE_CENTRAL 4152 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4153 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4154 if (sm_sc_only_mode){ 4155 uint8_t auth_req = packet[1]; 4156 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4157 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4158 return; 4159 } 4160 } 4161 #else 4162 UNUSED(packet); 4163 #endif 4164 4165 int have_ltk; 4166 uint8_t ltk[16]; 4167 4168 // IRK complete? 4169 switch (sm_conn->sm_irk_lookup_state){ 4170 case IRK_LOOKUP_FAILED: 4171 // start pairing 4172 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4173 break; 4174 case IRK_LOOKUP_SUCCEEDED: 4175 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4176 have_ltk = !sm_is_null_key(ltk); 4177 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4178 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4179 // start re-encrypt if we have LTK and the connection is not already encrypted 4180 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4181 } else { 4182 // start pairing 4183 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4184 } 4185 break; 4186 default: 4187 // otherwise, store security request 4188 sm_conn->sm_security_request_received = 1; 4189 break; 4190 } 4191 } 4192 #endif 4193 4194 static uint8_t sm_pdu_validate_and_get_opcode(uint8_t packet_type, const uint8_t *packet, uint16_t size){ 4195 4196 // size of complete sm_pdu used to validate input 4197 static const uint8_t sm_pdu_size[] = { 4198 0, // 0x00 invalid opcode 4199 7, // 0x01 pairing request 4200 7, // 0x02 pairing response 4201 17, // 0x03 pairing confirm 4202 17, // 0x04 pairing random 4203 2, // 0x05 pairing failed 4204 17, // 0x06 encryption information 4205 11, // 0x07 master identification 4206 17, // 0x08 identification information 4207 8, // 0x09 identify address information 4208 17, // 0x0a signing information 4209 2, // 0x0b security request 4210 65, // 0x0c pairing public key 4211 17, // 0x0d pairing dhk check 4212 2, // 0x0e keypress notification 4213 }; 4214 4215 if (packet_type != SM_DATA_PACKET) return 0; 4216 if (size == 0u) return 0; 4217 4218 uint8_t sm_pdu_code = packet[0]; 4219 4220 // validate pdu size 4221 if (sm_pdu_code >= sizeof(sm_pdu_size)) return 0; 4222 if (sm_pdu_size[sm_pdu_code] != size) return 0; 4223 4224 return sm_pdu_code; 4225 } 4226 4227 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4228 4229 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4230 sm_run(); 4231 } 4232 4233 uint8_t sm_pdu_code = sm_pdu_validate_and_get_opcode(packet_type, packet, size); 4234 if (sm_pdu_code == 0) return; 4235 4236 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4237 if (!sm_conn) return; 4238 4239 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4240 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4241 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4242 sm_done_for_handle(con_handle); 4243 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4244 return; 4245 } 4246 4247 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4248 4249 int err; 4250 UNUSED(err); 4251 4252 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4253 uint8_t buffer[5]; 4254 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4255 buffer[1] = 3; 4256 little_endian_store_16(buffer, 2, con_handle); 4257 buffer[4] = packet[1]; 4258 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4259 return; 4260 } 4261 4262 switch (sm_conn->sm_engine_state){ 4263 4264 // a sm timeout requires a new physical connection 4265 case SM_GENERAL_TIMEOUT: 4266 return; 4267 4268 #ifdef ENABLE_LE_CENTRAL 4269 4270 // Initiator 4271 case SM_INITIATOR_CONNECTED: 4272 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4273 sm_pdu_received_in_wrong_state(sm_conn); 4274 break; 4275 } 4276 sm_initiator_connected_handle_security_request(sm_conn, packet); 4277 break; 4278 4279 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4280 // Core 5, Vol 3, Part H, 2.4.6: 4281 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4282 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4283 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4284 log_info("Ignoring Security Request"); 4285 break; 4286 } 4287 4288 // all other pdus are incorrect 4289 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4290 sm_pdu_received_in_wrong_state(sm_conn); 4291 break; 4292 } 4293 4294 // store pairing request 4295 (void)memcpy(&setup->sm_s_pres, packet, 4296 sizeof(sm_pairing_packet_t)); 4297 err = sm_stk_generation_init(sm_conn); 4298 4299 #ifdef ENABLE_TESTING_SUPPORT 4300 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4301 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4302 err = test_pairing_failure; 4303 } 4304 #endif 4305 4306 if (err != 0){ 4307 sm_pairing_error(sm_conn, err); 4308 break; 4309 } 4310 4311 // generate random number first, if we need to show passkey 4312 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4313 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); 4314 break; 4315 } 4316 4317 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4318 if (setup->sm_use_secure_connections){ 4319 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4320 if (setup->sm_stk_generation_method == JUST_WORKS){ 4321 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4322 sm_trigger_user_response(sm_conn); 4323 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4324 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4325 } 4326 } else { 4327 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4328 } 4329 break; 4330 } 4331 #endif 4332 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4333 sm_trigger_user_response(sm_conn); 4334 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4335 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4336 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); 4337 } 4338 break; 4339 4340 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4341 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4342 sm_pdu_received_in_wrong_state(sm_conn); 4343 break; 4344 } 4345 4346 // store s_confirm 4347 reverse_128(&packet[1], setup->sm_peer_confirm); 4348 4349 // abort if s_confirm matches m_confirm 4350 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4351 sm_pdu_received_in_wrong_state(sm_conn); 4352 break; 4353 } 4354 4355 #ifdef ENABLE_TESTING_SUPPORT 4356 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4357 log_info("testing_support: reset confirm value"); 4358 memset(setup->sm_peer_confirm, 0, 16); 4359 } 4360 #endif 4361 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4362 break; 4363 4364 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4365 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4366 sm_pdu_received_in_wrong_state(sm_conn); 4367 break;; 4368 } 4369 4370 // received random value 4371 reverse_128(&packet[1], setup->sm_peer_random); 4372 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4373 break; 4374 4375 case SM_PH4_W4_CONNECTION_ENCRYPTED: 4376 // ignore Security Request, see SM_INITIATOR_PH1_W4_PAIRING_RESPONSE above 4377 if (sm_pdu_code != SM_CODE_SECURITY_REQUEST){ 4378 sm_pdu_received_in_wrong_state(sm_conn); 4379 } 4380 break; 4381 #endif 4382 4383 #ifdef ENABLE_LE_PERIPHERAL 4384 // Responder 4385 case SM_RESPONDER_IDLE: 4386 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4387 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4388 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4389 sm_pdu_received_in_wrong_state(sm_conn); 4390 break;; 4391 } 4392 4393 // store pairing request 4394 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4395 4396 // check if IRK completed 4397 switch (sm_conn->sm_irk_lookup_state){ 4398 case IRK_LOOKUP_SUCCEEDED: 4399 case IRK_LOOKUP_FAILED: 4400 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4401 break; 4402 default: 4403 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4404 break; 4405 } 4406 break; 4407 #endif 4408 4409 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4410 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4411 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4412 sm_pdu_received_in_wrong_state(sm_conn); 4413 break; 4414 } 4415 4416 // store public key for DH Key calculation 4417 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4418 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4419 4420 // CVE-2020-26558: abort pairing if remote uses the same public key 4421 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4422 log_info("Remote PK matches ours"); 4423 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4424 break; 4425 } 4426 4427 // validate public key 4428 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4429 if (err != 0){ 4430 log_info("sm: peer public key invalid %x", err); 4431 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4432 break; 4433 } 4434 4435 // start calculating dhkey 4436 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); 4437 4438 4439 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4440 if (IS_RESPONDER(sm_conn->sm_role)){ 4441 // responder 4442 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4443 } else { 4444 // initiator 4445 // stk generation method 4446 // passkey entry: notify app to show passkey or to request passkey 4447 switch (setup->sm_stk_generation_method){ 4448 case JUST_WORKS: 4449 case NUMERIC_COMPARISON: 4450 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4451 break; 4452 case PK_RESP_INPUT: 4453 sm_sc_start_calculating_local_confirm(sm_conn); 4454 break; 4455 case PK_INIT_INPUT: 4456 case PK_BOTH_INPUT: 4457 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4458 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4459 break; 4460 } 4461 sm_sc_start_calculating_local_confirm(sm_conn); 4462 break; 4463 case OOB: 4464 // generate Nx 4465 log_info("Generate Na"); 4466 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); 4467 break; 4468 default: 4469 btstack_assert(false); 4470 break; 4471 } 4472 } 4473 break; 4474 4475 case SM_SC_W4_CONFIRMATION: 4476 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4477 sm_pdu_received_in_wrong_state(sm_conn); 4478 break; 4479 } 4480 // received confirm value 4481 reverse_128(&packet[1], setup->sm_peer_confirm); 4482 4483 #ifdef ENABLE_TESTING_SUPPORT 4484 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4485 log_info("testing_support: reset confirm value"); 4486 memset(setup->sm_peer_confirm, 0, 16); 4487 } 4488 #endif 4489 if (IS_RESPONDER(sm_conn->sm_role)){ 4490 // responder 4491 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4492 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4493 // still waiting for passkey 4494 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4495 break; 4496 } 4497 } 4498 sm_sc_start_calculating_local_confirm(sm_conn); 4499 } else { 4500 // initiator 4501 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4502 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); 4503 } else { 4504 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4505 } 4506 } 4507 break; 4508 4509 case SM_SC_W4_PAIRING_RANDOM: 4510 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4511 sm_pdu_received_in_wrong_state(sm_conn); 4512 break; 4513 } 4514 4515 // received random value 4516 reverse_128(&packet[1], setup->sm_peer_nonce); 4517 4518 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4519 // only check for JUST WORK/NC in initiator role OR passkey entry 4520 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4521 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4522 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4523 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4524 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4525 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4526 break; 4527 } 4528 4529 // OOB 4530 if (setup->sm_stk_generation_method == OOB){ 4531 4532 // setup local random, set to zero if remote did not receive our data 4533 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4534 if (IS_RESPONDER(sm_conn->sm_role)){ 4535 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4536 log_info("Reset rb as A does not have OOB data"); 4537 memset(setup->sm_rb, 0, 16); 4538 } else { 4539 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4540 log_info("Use stored rb"); 4541 log_info_hexdump(setup->sm_rb, 16); 4542 } 4543 } else { 4544 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4545 log_info("Reset ra as B does not have OOB data"); 4546 memset(setup->sm_ra, 0, 16); 4547 } else { 4548 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4549 log_info("Use stored ra"); 4550 log_info_hexdump(setup->sm_ra, 16); 4551 } 4552 } 4553 4554 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4555 if (setup->sm_have_oob_data){ 4556 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4557 break; 4558 } 4559 } 4560 4561 // TODO: we only get here for Responder role with JW/NC 4562 sm_sc_state_after_receiving_random(sm_conn); 4563 break; 4564 4565 case SM_SC_W2_CALCULATE_G2: 4566 case SM_SC_W4_CALCULATE_G2: 4567 case SM_SC_W4_CALCULATE_DHKEY: 4568 case SM_SC_W2_CALCULATE_F5_SALT: 4569 case SM_SC_W4_CALCULATE_F5_SALT: 4570 case SM_SC_W2_CALCULATE_F5_MACKEY: 4571 case SM_SC_W4_CALCULATE_F5_MACKEY: 4572 case SM_SC_W2_CALCULATE_F5_LTK: 4573 case SM_SC_W4_CALCULATE_F5_LTK: 4574 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4575 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4576 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4577 case SM_SC_W4_USER_RESPONSE: 4578 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4579 sm_pdu_received_in_wrong_state(sm_conn); 4580 break; 4581 } 4582 // store DHKey Check 4583 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4584 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4585 4586 // have we been only waiting for dhkey check command? 4587 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4588 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4589 } 4590 break; 4591 #endif 4592 4593 #ifdef ENABLE_LE_PERIPHERAL 4594 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4595 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4596 sm_pdu_received_in_wrong_state(sm_conn); 4597 break; 4598 } 4599 4600 // received confirm value 4601 reverse_128(&packet[1], setup->sm_peer_confirm); 4602 4603 #ifdef ENABLE_TESTING_SUPPORT 4604 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4605 log_info("testing_support: reset confirm value"); 4606 memset(setup->sm_peer_confirm, 0, 16); 4607 } 4608 #endif 4609 // notify client to hide shown passkey 4610 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4611 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4612 } 4613 4614 // handle user cancel pairing? 4615 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4616 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4617 break; 4618 } 4619 4620 // wait for user action? 4621 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4622 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4623 break; 4624 } 4625 4626 // calculate and send local_confirm 4627 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); 4628 break; 4629 4630 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4631 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4632 sm_pdu_received_in_wrong_state(sm_conn); 4633 break;; 4634 } 4635 4636 // received random value 4637 reverse_128(&packet[1], setup->sm_peer_random); 4638 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4639 break; 4640 #endif 4641 4642 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4643 case SM_PH3_RECEIVE_KEYS: 4644 switch(sm_pdu_code){ 4645 case SM_CODE_ENCRYPTION_INFORMATION: 4646 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4647 reverse_128(&packet[1], setup->sm_peer_ltk); 4648 break; 4649 4650 case SM_CODE_MASTER_IDENTIFICATION: 4651 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4652 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4653 reverse_64(&packet[3], setup->sm_peer_rand); 4654 break; 4655 4656 case SM_CODE_IDENTITY_INFORMATION: 4657 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4658 reverse_128(&packet[1], setup->sm_peer_irk); 4659 break; 4660 4661 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4662 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4663 setup->sm_peer_addr_type = packet[1]; 4664 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4665 break; 4666 4667 case SM_CODE_SIGNING_INFORMATION: 4668 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4669 reverse_128(&packet[1], setup->sm_peer_csrk); 4670 break; 4671 default: 4672 // Unexpected PDU 4673 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4674 break; 4675 } 4676 // done with key distribution? 4677 if (sm_key_distribution_all_received()){ 4678 4679 sm_key_distribution_handle_all_received(sm_conn); 4680 4681 if (IS_RESPONDER(sm_conn->sm_role)){ 4682 sm_key_distribution_complete_responder(sm_conn); 4683 } else { 4684 if (setup->sm_use_secure_connections){ 4685 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4686 } else { 4687 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); 4688 } 4689 } 4690 } 4691 break; 4692 4693 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4694 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4695 4696 // dedicated bonding complete 4697 hci_dedicated_bonding_defer_disconnect(sm_conn->sm_handle, false); 4698 4699 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4700 sm_pdu_received_in_wrong_state(sm_conn); 4701 break; 4702 } 4703 // store pairing response 4704 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4705 4706 // validate encryption key size 4707 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres)); 4708 // SC Only mandates 128 bit key size 4709 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4710 sm_conn->sm_actual_encryption_key_size = 0; 4711 } 4712 if (sm_conn->sm_actual_encryption_key_size == 0){ 4713 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4714 break; 4715 } 4716 4717 // prepare key exchange, LTK is derived locally 4718 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4719 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4720 4721 // skip receive if there are none 4722 if (sm_key_distribution_all_received()){ 4723 // distribute keys in run handles 'no keys to send' 4724 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4725 } else { 4726 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4727 } 4728 break; 4729 4730 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4731 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4732 sm_pdu_received_in_wrong_state(sm_conn); 4733 break; 4734 } 4735 // store pairing request 4736 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4737 // validate encryption key size 4738 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq)); 4739 // SC Only mandates 128 bit key size 4740 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4741 sm_conn->sm_actual_encryption_key_size = 0; 4742 } 4743 if (sm_conn->sm_actual_encryption_key_size == 0){ 4744 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4745 break; 4746 } 4747 // trigger response 4748 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4749 break; 4750 4751 case SM_BR_EDR_RECEIVE_KEYS: 4752 switch(sm_pdu_code){ 4753 case SM_CODE_IDENTITY_INFORMATION: 4754 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4755 reverse_128(&packet[1], setup->sm_peer_irk); 4756 break; 4757 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4758 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4759 setup->sm_peer_addr_type = packet[1]; 4760 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4761 break; 4762 case SM_CODE_SIGNING_INFORMATION: 4763 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4764 reverse_128(&packet[1], setup->sm_peer_csrk); 4765 break; 4766 default: 4767 // Unexpected PDU 4768 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4769 break; 4770 } 4771 4772 // all keys received 4773 if (sm_key_distribution_all_received()){ 4774 if (IS_RESPONDER(sm_conn->sm_role)){ 4775 // responder -> keys exchanged, derive LE LTK 4776 sm_ctkd_start_from_br_edr(sm_conn); 4777 } else { 4778 // initiator -> send our keys if any 4779 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4780 } 4781 } 4782 break; 4783 #endif 4784 4785 default: 4786 // Unexpected PDU 4787 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4788 sm_pdu_received_in_wrong_state(sm_conn); 4789 break; 4790 } 4791 4792 // try to send next pdu 4793 sm_trigger_run(); 4794 } 4795 4796 // Security Manager Client API 4797 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4798 sm_get_oob_data = get_oob_data_callback; 4799 } 4800 4801 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)){ 4802 sm_get_sc_oob_data = get_sc_oob_data_callback; 4803 } 4804 4805 void sm_register_ltk_callback( bool (*get_ltk_callback)(hci_con_handle_t con_handle, uint8_t address_type, bd_addr_t addr, uint8_t * ltk)){ 4806 sm_get_ltk_callback = get_ltk_callback; 4807 } 4808 4809 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4810 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4811 } 4812 4813 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4814 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4815 } 4816 4817 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4818 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4819 } 4820 4821 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4822 sm_min_encryption_key_size = min_size; 4823 sm_max_encryption_key_size = max_size; 4824 } 4825 4826 void sm_set_authentication_requirements(uint8_t auth_req){ 4827 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4828 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4829 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4830 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4831 } 4832 #endif 4833 sm_auth_req = auth_req; 4834 } 4835 4836 void sm_set_io_capabilities(io_capability_t io_capability){ 4837 sm_io_capabilities = io_capability; 4838 } 4839 4840 #ifdef ENABLE_LE_PERIPHERAL 4841 void sm_set_request_security(int enable){ 4842 sm_slave_request_security = enable; 4843 } 4844 #endif 4845 4846 void sm_set_er(sm_key_t er){ 4847 (void)memcpy(sm_persistent_er, er, 16); 4848 } 4849 4850 void sm_set_ir(sm_key_t ir){ 4851 (void)memcpy(sm_persistent_ir, ir, 16); 4852 } 4853 4854 // Testing support only 4855 void sm_test_set_irk(sm_key_t irk){ 4856 (void)memcpy(sm_persistent_irk, irk, 16); 4857 dkg_state = DKG_CALC_DHK; 4858 test_use_fixed_local_irk = true; 4859 } 4860 4861 void sm_test_use_fixed_local_csrk(void){ 4862 test_use_fixed_local_csrk = true; 4863 } 4864 4865 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4866 static void sm_ec_generated(void * arg){ 4867 UNUSED(arg); 4868 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4869 // trigger pairing if pending for ec key 4870 sm_trigger_run(); 4871 } 4872 static void sm_ec_generate_new_key(void){ 4873 log_info("sm: generate new ec key"); 4874 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4875 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4876 } 4877 #endif 4878 4879 #ifdef ENABLE_TESTING_SUPPORT 4880 void sm_test_set_pairing_failure(int reason){ 4881 test_pairing_failure = reason; 4882 } 4883 #endif 4884 4885 static void sm_state_reset(void) { 4886 #ifdef USE_CMAC_ENGINE 4887 sm_cmac_active = 0; 4888 #endif 4889 dkg_state = DKG_W4_WORKING; 4890 rau_state = RAU_IDLE; 4891 sm_aes128_state = SM_AES128_IDLE; 4892 sm_address_resolution_test = -1; // no private address to resolve yet 4893 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4894 sm_address_resolution_general_queue = NULL; 4895 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4896 sm_persistent_keys_random_active = false; 4897 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4898 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4899 #endif 4900 } 4901 4902 void sm_init(void){ 4903 4904 if (sm_initialized) return; 4905 4906 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4907 sm_er_ir_set_default(); 4908 4909 // defaults 4910 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4911 | SM_STK_GENERATION_METHOD_OOB 4912 | SM_STK_GENERATION_METHOD_PASSKEY 4913 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4914 4915 sm_max_encryption_key_size = 16; 4916 sm_min_encryption_key_size = 7; 4917 4918 sm_fixed_passkey_in_display_role = 0xffffffffU; 4919 sm_reconstruct_ltk_without_le_device_db_entry = true; 4920 4921 gap_random_adress_update_period = 15 * 60 * 1000L; 4922 4923 test_use_fixed_local_csrk = false; 4924 4925 // other 4926 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4927 4928 // register for HCI Events 4929 hci_event_callback_registration.callback = &sm_event_packet_handler; 4930 hci_add_event_handler(&hci_event_callback_registration); 4931 4932 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4933 // register for L2CAP events 4934 l2cap_event_callback_registration.callback = &sm_event_packet_handler; 4935 l2cap_add_event_handler(&l2cap_event_callback_registration); 4936 #endif 4937 4938 // 4939 btstack_crypto_init(); 4940 4941 // init le_device_db 4942 le_device_db_init(); 4943 4944 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4945 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4946 #ifdef ENABLE_CLASSIC 4947 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); 4948 #endif 4949 4950 // state 4951 sm_state_reset(); 4952 4953 sm_initialized = true; 4954 } 4955 4956 void sm_deinit(void){ 4957 sm_initialized = false; 4958 btstack_run_loop_remove_timer(&sm_run_timer); 4959 } 4960 4961 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4962 sm_fixed_passkey_in_display_role = passkey; 4963 } 4964 4965 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4966 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4967 } 4968 4969 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4970 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4971 if (!hci_con) return NULL; 4972 return &hci_con->sm_connection; 4973 } 4974 4975 static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk){ 4976 hci_connection_t * hci_con = hci_connection_for_handle(connection->sm_handle); 4977 btstack_assert(hci_con != NULL); 4978 memcpy(hci_con->link_key, ltk, 16); 4979 hci_con->link_key_type = 1; 4980 } 4981 4982 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4983 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4984 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4985 if (!hci_con) return NULL; 4986 return &hci_con->sm_connection; 4987 } 4988 #endif 4989 4990 // @deprecated: map onto sm_request_pairing 4991 void sm_send_security_request(hci_con_handle_t con_handle){ 4992 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4993 if (!sm_conn) return; 4994 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4995 sm_request_pairing(con_handle); 4996 } 4997 4998 // request pairing 4999 void sm_request_pairing(hci_con_handle_t con_handle){ 5000 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5001 if (!sm_conn) return; // wrong connection 5002 5003 bool have_ltk; 5004 uint8_t ltk[16]; 5005 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 5006 if (IS_RESPONDER(sm_conn->sm_role)){ 5007 switch (sm_conn->sm_engine_state){ 5008 case SM_GENERAL_IDLE: 5009 case SM_RESPONDER_IDLE: 5010 switch (sm_conn->sm_irk_lookup_state){ 5011 case IRK_LOOKUP_SUCCEEDED: 5012 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 5013 have_ltk = !sm_is_null_key(ltk); 5014 log_info("have ltk %u", have_ltk); 5015 if (have_ltk){ 5016 sm_conn->sm_pairing_requested = 1; 5017 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5018 sm_reencryption_started(sm_conn); 5019 break; 5020 } 5021 /* fall through */ 5022 5023 case IRK_LOOKUP_FAILED: 5024 sm_conn->sm_pairing_requested = 1; 5025 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 5026 sm_pairing_started(sm_conn); 5027 break; 5028 default: 5029 log_info("irk lookup pending"); 5030 sm_conn->sm_pairing_requested = 1; 5031 break; 5032 } 5033 break; 5034 default: 5035 break; 5036 } 5037 } else { 5038 // used as a trigger to start central/master/initiator security procedures 5039 switch (sm_conn->sm_engine_state){ 5040 case SM_INITIATOR_CONNECTED: 5041 switch (sm_conn->sm_irk_lookup_state){ 5042 case IRK_LOOKUP_SUCCEEDED: 5043 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 5044 have_ltk = !sm_is_null_key(ltk); 5045 log_info("have ltk %u", have_ltk); 5046 if (have_ltk){ 5047 sm_conn->sm_pairing_requested = 1; 5048 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 5049 break; 5050 } 5051 /* fall through */ 5052 5053 case IRK_LOOKUP_FAILED: 5054 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5055 break; 5056 default: 5057 log_info("irk lookup pending"); 5058 sm_conn->sm_pairing_requested = 1; 5059 break; 5060 } 5061 break; 5062 case SM_GENERAL_REENCRYPTION_FAILED: 5063 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 5064 break; 5065 case SM_GENERAL_IDLE: 5066 sm_conn->sm_pairing_requested = 1; 5067 break; 5068 default: 5069 break; 5070 } 5071 } 5072 sm_trigger_run(); 5073 } 5074 5075 // called by client app on authorization request 5076 void sm_authorization_decline(hci_con_handle_t con_handle){ 5077 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5078 if (!sm_conn) return; // wrong connection 5079 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 5080 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 5081 } 5082 5083 void sm_authorization_grant(hci_con_handle_t con_handle){ 5084 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5085 if (!sm_conn) return; // wrong connection 5086 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 5087 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 5088 } 5089 5090 // GAP Bonding API 5091 5092 void sm_bonding_decline(hci_con_handle_t con_handle){ 5093 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5094 if (!sm_conn) return; // wrong connection 5095 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 5096 log_info("decline, state %u", sm_conn->sm_engine_state); 5097 switch(sm_conn->sm_engine_state){ 5098 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5099 case SM_SC_W4_USER_RESPONSE: 5100 case SM_SC_W4_CONFIRMATION: 5101 case SM_SC_W4_PUBLIC_KEY_COMMAND: 5102 #endif 5103 case SM_PH1_W4_USER_RESPONSE: 5104 switch (setup->sm_stk_generation_method){ 5105 case PK_RESP_INPUT: 5106 case PK_INIT_INPUT: 5107 case PK_BOTH_INPUT: 5108 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 5109 break; 5110 case NUMERIC_COMPARISON: 5111 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 5112 break; 5113 case JUST_WORKS: 5114 case OOB: 5115 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 5116 break; 5117 default: 5118 btstack_assert(false); 5119 break; 5120 } 5121 break; 5122 default: 5123 break; 5124 } 5125 sm_trigger_run(); 5126 } 5127 5128 void sm_just_works_confirm(hci_con_handle_t con_handle){ 5129 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5130 if (!sm_conn) return; // wrong connection 5131 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 5132 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5133 if (setup->sm_use_secure_connections){ 5134 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 5135 } else { 5136 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); 5137 } 5138 } 5139 5140 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5141 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5142 sm_sc_prepare_dhkey_check(sm_conn); 5143 } 5144 #endif 5145 5146 sm_trigger_run(); 5147 } 5148 5149 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5150 // for now, it's the same 5151 sm_just_works_confirm(con_handle); 5152 } 5153 5154 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5155 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5156 if (!sm_conn) return; // wrong connection 5157 sm_reset_tk(); 5158 big_endian_store_32(setup->sm_tk, 12, passkey); 5159 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5160 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5161 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); 5162 } 5163 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5164 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5165 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5166 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5167 sm_sc_start_calculating_local_confirm(sm_conn); 5168 } 5169 #endif 5170 sm_trigger_run(); 5171 } 5172 5173 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5174 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5175 if (!sm_conn) return; // wrong connection 5176 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5177 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5178 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5179 switch (action){ 5180 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5181 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5182 flags |= (1u << action); 5183 break; 5184 case SM_KEYPRESS_PASSKEY_CLEARED: 5185 // clear counter, keypress & erased flags + set passkey cleared 5186 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5187 break; 5188 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5189 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 5190 // erase actions queued 5191 num_actions--; 5192 if (num_actions == 0u){ 5193 // clear counter, keypress & erased flags 5194 flags &= 0x19u; 5195 } 5196 break; 5197 } 5198 num_actions++; 5199 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5200 break; 5201 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5202 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5203 // enter actions queued 5204 num_actions--; 5205 if (num_actions == 0u){ 5206 // clear counter, keypress & erased flags 5207 flags &= 0x19u; 5208 } 5209 break; 5210 } 5211 num_actions++; 5212 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5213 break; 5214 default: 5215 break; 5216 } 5217 setup->sm_keypress_notification = (num_actions << 5) | flags; 5218 sm_trigger_run(); 5219 } 5220 5221 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5222 static void sm_handle_random_result_oob(void * arg){ 5223 UNUSED(arg); 5224 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5225 sm_trigger_run(); 5226 } 5227 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5228 5229 static btstack_crypto_random_t sm_crypto_random_oob_request; 5230 5231 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5232 sm_sc_oob_callback = callback; 5233 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5234 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5235 return 0; 5236 } 5237 #endif 5238 5239 /** 5240 * @brief Get Identity Resolving state 5241 * @param con_handle 5242 * @return irk_lookup_state_t 5243 */ 5244 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5245 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5246 if (!sm_conn) return IRK_LOOKUP_IDLE; 5247 return sm_conn->sm_irk_lookup_state; 5248 } 5249 5250 /** 5251 * @brief Identify device in LE Device DB 5252 * @param handle 5253 * @return index from le_device_db or -1 if not found/identified 5254 */ 5255 int sm_le_device_index(hci_con_handle_t con_handle ){ 5256 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5257 if (!sm_conn) return -1; 5258 return sm_conn->sm_le_db_index; 5259 } 5260 5261 uint8_t sm_get_ltk(hci_con_handle_t con_handle, sm_key_t ltk){ 5262 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 5263 if (hci_connection == NULL){ 5264 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 5265 } 5266 if (hci_connection->link_key_type == 0){ 5267 return ERROR_CODE_PIN_OR_KEY_MISSING; 5268 } 5269 memcpy(ltk, hci_connection->link_key, 16); 5270 return ERROR_CODE_SUCCESS; 5271 } 5272 5273 static int gap_random_address_type_requires_updates(void){ 5274 switch (gap_random_adress_type){ 5275 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5276 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5277 return 0; 5278 default: 5279 return 1; 5280 } 5281 } 5282 5283 static uint8_t own_address_type(void){ 5284 switch (gap_random_adress_type){ 5285 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5286 return BD_ADDR_TYPE_LE_PUBLIC; 5287 default: 5288 return BD_ADDR_TYPE_LE_RANDOM; 5289 } 5290 } 5291 5292 // GAP LE API 5293 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5294 gap_random_address_update_stop(); 5295 gap_random_adress_type = random_address_type; 5296 hci_le_set_own_address_type(own_address_type()); 5297 if (!gap_random_address_type_requires_updates()) return; 5298 gap_random_address_update_start(); 5299 gap_random_address_trigger(); 5300 } 5301 5302 gap_random_address_type_t gap_random_address_get_mode(void){ 5303 return gap_random_adress_type; 5304 } 5305 5306 void gap_random_address_set_update_period(int period_ms){ 5307 gap_random_adress_update_period = period_ms; 5308 if (!gap_random_address_type_requires_updates()) return; 5309 gap_random_address_update_stop(); 5310 gap_random_address_update_start(); 5311 } 5312 5313 void gap_random_address_set(const bd_addr_t addr){ 5314 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5315 (void)memcpy(sm_random_address, addr, 6); 5316 // assert msb bits are set to '11' 5317 sm_random_address[0] |= 0xc0; 5318 hci_le_random_address_set(sm_random_address); 5319 } 5320 5321 #ifdef ENABLE_LE_PERIPHERAL 5322 /* 5323 * @brief Set Advertisement Paramters 5324 * @param adv_int_min 5325 * @param adv_int_max 5326 * @param adv_type 5327 * @param direct_address_type 5328 * @param direct_address 5329 * @param channel_map 5330 * @param filter_policy 5331 * 5332 * @note own_address_type is used from gap_random_address_set_mode 5333 */ 5334 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5335 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5336 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5337 direct_address_typ, direct_address, channel_map, filter_policy); 5338 } 5339 #endif 5340 5341 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5342 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5343 // wrong connection 5344 if (!sm_conn) return 0; 5345 // already encrypted 5346 if (sm_conn->sm_connection_encrypted) return 0; 5347 // irk status? 5348 switch(sm_conn->sm_irk_lookup_state){ 5349 case IRK_LOOKUP_FAILED: 5350 // done, cannot setup encryption 5351 return 0; 5352 case IRK_LOOKUP_SUCCEEDED: 5353 break; 5354 default: 5355 // IR Lookup pending 5356 return 1; 5357 } 5358 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5359 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5360 if (sm_conn->sm_role){ 5361 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5362 } else { 5363 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5364 } 5365 } 5366 5367 void sm_set_secure_connections_only_mode(bool enable){ 5368 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5369 sm_sc_only_mode = enable; 5370 #else 5371 // SC Only mode not possible without support for SC 5372 btstack_assert(enable == false); 5373 #endif 5374 } 5375 5376 const uint8_t * gap_get_persistent_irk(void){ 5377 return sm_persistent_irk; 5378 } 5379 5380 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5381 uint16_t i; 5382 for (i=0; i < le_device_db_max_count(); i++){ 5383 bd_addr_t entry_address; 5384 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5385 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5386 // skip unused entries 5387 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5388 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5389 sm_remove_le_device_db_entry(i); 5390 break; 5391 } 5392 } 5393 } 5394