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 int sm_address_resolution_ah_calculation_active; 257 static uint8_t sm_address_resolution_addr_type; 258 static bd_addr_t sm_address_resolution_address; 259 static void * sm_address_resolution_context; 260 static address_resolution_mode_t sm_address_resolution_mode; 261 static btstack_linked_list_t sm_address_resolution_general_queue; 262 263 // aes128 crypto engine. 264 static sm_aes128_state_t sm_aes128_state; 265 266 // crypto 267 static btstack_crypto_random_t sm_crypto_random_request; 268 static btstack_crypto_aes128_t sm_crypto_aes128_request; 269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 270 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 271 #endif 272 273 // temp storage for random data 274 static uint8_t sm_random_data[8]; 275 static uint8_t sm_aes128_key[16]; 276 static uint8_t sm_aes128_plaintext[16]; 277 static uint8_t sm_aes128_ciphertext[16]; 278 279 // to receive hci events 280 static btstack_packet_callback_registration_t hci_event_callback_registration; 281 282 /* to dispatch sm event */ 283 static btstack_linked_list_t sm_event_handlers; 284 285 /* to schedule calls to sm_run */ 286 static btstack_timer_source_t sm_run_timer; 287 288 // LE Secure Connections 289 #ifdef ENABLE_LE_SECURE_CONNECTIONS 290 static ec_key_generation_state_t ec_key_generation_state; 291 static uint8_t ec_q[64]; 292 #endif 293 294 // 295 // Volume 3, Part H, Chapter 24 296 // "Security shall be initiated by the Security Manager in the device in the master role. 297 // The device in the slave role shall be the responding device." 298 // -> master := initiator, slave := responder 299 // 300 301 // data needed for security setup 302 typedef struct sm_setup_context { 303 304 btstack_timer_source_t sm_timeout; 305 306 // user response, (Phase 1 and/or 2) 307 uint8_t sm_user_response; 308 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 309 310 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 311 uint8_t sm_key_distribution_send_set; 312 uint8_t sm_key_distribution_sent_set; 313 uint8_t sm_key_distribution_expected_set; 314 uint8_t sm_key_distribution_received_set; 315 316 // Phase 2 (Pairing over SMP) 317 stk_generation_method_t sm_stk_generation_method; 318 sm_key_t sm_tk; 319 uint8_t sm_have_oob_data; 320 uint8_t sm_use_secure_connections; 321 322 sm_key_t sm_c1_t3_value; // c1 calculation 323 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 324 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 325 sm_key_t sm_local_random; 326 sm_key_t sm_local_confirm; 327 sm_key_t sm_peer_random; 328 sm_key_t sm_peer_confirm; 329 uint8_t sm_m_addr_type; // address and type can be removed 330 uint8_t sm_s_addr_type; // '' 331 bd_addr_t sm_m_address; // '' 332 bd_addr_t sm_s_address; // '' 333 sm_key_t sm_ltk; 334 335 uint8_t sm_state_vars; 336 #ifdef ENABLE_LE_SECURE_CONNECTIONS 337 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 338 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 339 sm_key_t sm_local_nonce; // might be combined with sm_local_random 340 uint8_t sm_dhkey[32]; 341 sm_key_t sm_peer_dhkey_check; 342 sm_key_t sm_local_dhkey_check; 343 sm_key_t sm_ra; 344 sm_key_t sm_rb; 345 sm_key_t sm_t; // used for f5 and h6 346 sm_key_t sm_mackey; 347 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 348 #endif 349 350 // Phase 3 351 352 // key distribution, we generate 353 uint16_t sm_local_y; 354 uint16_t sm_local_div; 355 uint16_t sm_local_ediv; 356 uint8_t sm_local_rand[8]; 357 sm_key_t sm_local_ltk; 358 sm_key_t sm_local_csrk; 359 sm_key_t sm_local_irk; 360 // sm_local_address/addr_type not needed 361 362 // key distribution, received from peer 363 uint16_t sm_peer_y; 364 uint16_t sm_peer_div; 365 uint16_t sm_peer_ediv; 366 uint8_t sm_peer_rand[8]; 367 sm_key_t sm_peer_ltk; 368 sm_key_t sm_peer_irk; 369 sm_key_t sm_peer_csrk; 370 uint8_t sm_peer_addr_type; 371 bd_addr_t sm_peer_address; 372 #ifdef ENABLE_LE_SIGNED_WRITE 373 int sm_le_device_index; 374 #endif 375 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 376 link_key_t sm_link_key; 377 link_key_type_t sm_link_key_type; 378 #endif 379 } sm_setup_context_t; 380 381 // 382 static sm_setup_context_t the_setup; 383 static sm_setup_context_t * setup = &the_setup; 384 385 // active connection - the one for which the_setup is used for 386 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 387 388 // @return 1 if oob data is available 389 // stores oob data in provided 16 byte buffer if not null 390 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 391 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); 392 static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); 393 394 static void sm_run(void); 395 static void sm_state_reset(void); 396 static void sm_done_for_handle(hci_con_handle_t con_handle); 397 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 398 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 399 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); 400 #endif 401 static inline int sm_calc_actual_encryption_key_size(int other); 402 static int sm_validate_stk_generation_method(void); 403 static void sm_handle_encryption_result_address_resolution(void *arg); 404 static void sm_handle_encryption_result_dkg_dhk(void *arg); 405 static void sm_handle_encryption_result_dkg_irk(void *arg); 406 static void sm_handle_encryption_result_enc_a(void *arg); 407 static void sm_handle_encryption_result_enc_b(void *arg); 408 static void sm_handle_encryption_result_enc_c(void *arg); 409 static void sm_handle_encryption_result_enc_csrk(void *arg); 410 static void sm_handle_encryption_result_enc_d(void * arg); 411 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 412 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 413 #ifdef ENABLE_LE_PERIPHERAL 414 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 415 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 416 #endif 417 static void sm_handle_encryption_result_enc_stk(void *arg); 418 static void sm_handle_encryption_result_rau(void *arg); 419 static void sm_handle_random_result_ph2_tk(void * arg); 420 static void sm_handle_random_result_rau(void * arg); 421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 422 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)); 423 static void sm_ec_generate_new_key(void); 424 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 425 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 426 static int sm_passkey_entry(stk_generation_method_t method); 427 #endif 428 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 429 430 static void log_info_hex16(const char * name, uint16_t value){ 431 log_info("%-6s 0x%04x", name, value); 432 } 433 434 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 435 // return packet[0]; 436 // } 437 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 438 return packet[1]; 439 } 440 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 441 return packet[2]; 442 } 443 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 444 return packet[3]; 445 } 446 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 447 return packet[4]; 448 } 449 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 450 return packet[5]; 451 } 452 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 453 return packet[6]; 454 } 455 456 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 457 packet[0] = code; 458 } 459 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 460 packet[1] = io_capability; 461 } 462 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 463 packet[2] = oob_data_flag; 464 } 465 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 466 packet[3] = auth_req; 467 } 468 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 469 packet[4] = max_encryption_key_size; 470 } 471 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 472 packet[5] = initiator_key_distribution; 473 } 474 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 475 packet[6] = responder_key_distribution; 476 } 477 478 static bool sm_is_null_random(uint8_t random[8]){ 479 return btstack_is_null(random, 8); 480 } 481 482 static bool sm_is_null_key(uint8_t * key){ 483 return btstack_is_null(key, 16); 484 } 485 486 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 487 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 488 UNUSED(ts); 489 sm_run(); 490 } 491 static void sm_trigger_run(void){ 492 if (!sm_initialized) return; 493 (void)btstack_run_loop_remove_timer(&sm_run_timer); 494 btstack_run_loop_set_timer(&sm_run_timer, 0); 495 btstack_run_loop_add_timer(&sm_run_timer); 496 } 497 498 // Key utils 499 static void sm_reset_tk(void){ 500 int i; 501 for (i=0;i<16;i++){ 502 setup->sm_tk[i] = 0; 503 } 504 } 505 506 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 507 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 508 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 509 int i; 510 for (i = max_encryption_size ; i < 16 ; i++){ 511 key[15-i] = 0; 512 } 513 } 514 515 // ER / IR checks 516 static void sm_er_ir_set_default(void){ 517 int i; 518 for (i=0;i<16;i++){ 519 sm_persistent_er[i] = 0x30 + i; 520 sm_persistent_ir[i] = 0x90 + i; 521 } 522 } 523 524 static int sm_er_is_default(void){ 525 int i; 526 for (i=0;i<16;i++){ 527 if (sm_persistent_er[i] != (0x30+i)) return 0; 528 } 529 return 1; 530 } 531 532 static int sm_ir_is_default(void){ 533 int i; 534 for (i=0;i<16;i++){ 535 if (sm_persistent_ir[i] != (0x90+i)) return 0; 536 } 537 return 1; 538 } 539 540 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 541 UNUSED(channel); 542 543 // log event 544 hci_dump_packet(packet_type, 1, packet, size); 545 // dispatch to all event handlers 546 btstack_linked_list_iterator_t it; 547 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 548 while (btstack_linked_list_iterator_has_next(&it)){ 549 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 550 entry->callback(packet_type, 0, packet, size); 551 } 552 } 553 554 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){ 555 event[0] = type; 556 event[1] = event_size - 2; 557 little_endian_store_16(event, 2, con_handle); 558 event[4] = addr_type; 559 reverse_bd_addr(address, &event[5]); 560 } 561 562 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 563 uint8_t event[11]; 564 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 565 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 566 } 567 568 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){ 569 // fetch addr and addr type from db, only called for valid entries 570 bd_addr_t identity_address; 571 int identity_address_type; 572 le_device_db_info(index, &identity_address_type, identity_address, NULL); 573 574 uint8_t event[20]; 575 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 576 event[11] = identity_address_type; 577 reverse_bd_addr(identity_address, &event[12]); 578 little_endian_store_16(event, 18, index); 579 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 580 } 581 582 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){ 583 uint8_t event[12]; 584 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 585 event[11] = status; 586 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 587 } 588 589 590 static void sm_reencryption_started(sm_connection_t * sm_conn){ 591 592 if (sm_conn->sm_reencryption_active) return; 593 594 sm_conn->sm_reencryption_active = true; 595 596 int identity_addr_type; 597 bd_addr_t identity_addr; 598 if (sm_conn->sm_le_db_index >= 0){ 599 // fetch addr and addr type from db, only called for valid entries 600 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 601 } else { 602 // for legacy pairing with LTK re-construction, use current peer addr 603 identity_addr_type = sm_conn->sm_peer_addr_type; 604 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 605 } 606 607 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 608 } 609 610 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 611 612 if (!sm_conn->sm_reencryption_active) return; 613 614 sm_conn->sm_reencryption_active = false; 615 616 int identity_addr_type; 617 bd_addr_t identity_addr; 618 if (sm_conn->sm_le_db_index >= 0){ 619 // fetch addr and addr type from db, only called for valid entries 620 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 621 } else { 622 // for legacy pairing with LTK re-construction, use current peer addr 623 identity_addr_type = sm_conn->sm_peer_addr_type; 624 memcpy(identity_addr, sm_conn->sm_peer_address, 6); 625 } 626 627 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 628 } 629 630 static void sm_pairing_started(sm_connection_t * sm_conn){ 631 632 if (sm_conn->sm_pairing_active) return; 633 634 sm_conn->sm_pairing_active = true; 635 636 uint8_t event[11]; 637 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 638 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 639 } 640 641 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 642 643 if (!sm_conn->sm_pairing_active) return; 644 645 sm_conn->sm_pairing_active = false; 646 647 uint8_t event[13]; 648 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 649 event[11] = status; 650 event[12] = reason; 651 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 652 } 653 654 // SMP Timeout implementation 655 656 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 657 // the Security Manager Timer shall be reset and started. 658 // 659 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 660 // 661 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 662 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 663 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 664 // established. 665 666 static void sm_timeout_handler(btstack_timer_source_t * timer){ 667 log_info("SM timeout"); 668 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 669 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 670 sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); 671 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 672 sm_done_for_handle(sm_conn->sm_handle); 673 674 // trigger handling of next ready connection 675 sm_run(); 676 } 677 static void sm_timeout_start(sm_connection_t * sm_conn){ 678 btstack_run_loop_remove_timer(&setup->sm_timeout); 679 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 680 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 681 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 682 btstack_run_loop_add_timer(&setup->sm_timeout); 683 } 684 static void sm_timeout_stop(void){ 685 btstack_run_loop_remove_timer(&setup->sm_timeout); 686 } 687 static void sm_timeout_reset(sm_connection_t * sm_conn){ 688 sm_timeout_stop(); 689 sm_timeout_start(sm_conn); 690 } 691 692 // end of sm timeout 693 694 // GAP Random Address updates 695 static gap_random_address_type_t gap_random_adress_type; 696 static btstack_timer_source_t gap_random_address_update_timer; 697 static uint32_t gap_random_adress_update_period; 698 699 static void gap_random_address_trigger(void){ 700 log_info("gap_random_address_trigger, state %u", rau_state); 701 if (rau_state != RAU_IDLE) return; 702 rau_state = RAU_GET_RANDOM; 703 sm_trigger_run(); 704 } 705 706 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 707 UNUSED(timer); 708 709 log_info("GAP Random Address Update due"); 710 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 711 btstack_run_loop_add_timer(&gap_random_address_update_timer); 712 gap_random_address_trigger(); 713 } 714 715 static void gap_random_address_update_start(void){ 716 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 717 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 718 btstack_run_loop_add_timer(&gap_random_address_update_timer); 719 } 720 721 static void gap_random_address_update_stop(void){ 722 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 723 } 724 725 // ah(k,r) helper 726 // r = padding || r 727 // r - 24 bit value 728 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 729 // r'= padding || r 730 memset(r_prime, 0, 16); 731 (void)memcpy(&r_prime[13], r, 3); 732 } 733 734 // d1 helper 735 // d' = padding || r || d 736 // d,r - 16 bit values 737 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 738 // d'= padding || r || d 739 memset(d1_prime, 0, 16); 740 big_endian_store_16(d1_prime, 12, r); 741 big_endian_store_16(d1_prime, 14, d); 742 } 743 744 // calculate arguments for first AES128 operation in C1 function 745 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){ 746 747 // p1 = pres || preq || rat’ || iat’ 748 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 749 // cant octet of pres becomes the most significant octet of p1. 750 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 751 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 752 // p1 is 0x05000800000302070710000001010001." 753 754 sm_key_t p1; 755 reverse_56(pres, &p1[0]); 756 reverse_56(preq, &p1[7]); 757 p1[14] = rat; 758 p1[15] = iat; 759 log_info_key("p1", p1); 760 log_info_key("r", r); 761 762 // t1 = r xor p1 763 int i; 764 for (i=0;i<16;i++){ 765 t1[i] = r[i] ^ p1[i]; 766 } 767 log_info_key("t1", t1); 768 } 769 770 // calculate arguments for second AES128 operation in C1 function 771 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 772 // p2 = padding || ia || ra 773 // "The least significant octet of ra becomes the least significant octet of p2 and 774 // the most significant octet of padding becomes the most significant octet of p2. 775 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 776 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 777 778 sm_key_t p2; 779 memset(p2, 0, 16); 780 (void)memcpy(&p2[4], ia, 6); 781 (void)memcpy(&p2[10], ra, 6); 782 log_info_key("p2", p2); 783 784 // c1 = e(k, t2_xor_p2) 785 int i; 786 for (i=0;i<16;i++){ 787 t3[i] = t2[i] ^ p2[i]; 788 } 789 log_info_key("t3", t3); 790 } 791 792 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 793 log_info_key("r1", r1); 794 log_info_key("r2", r2); 795 (void)memcpy(&r_prime[8], &r2[8], 8); 796 (void)memcpy(&r_prime[0], &r1[8], 8); 797 } 798 799 800 // decide on stk generation based on 801 // - pairing request 802 // - io capabilities 803 // - OOB data availability 804 static void sm_setup_tk(void){ 805 806 // horizontal: initiator capabilities 807 // vertial: responder capabilities 808 static const stk_generation_method_t stk_generation_method [5] [5] = { 809 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 810 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 811 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 812 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 813 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 814 }; 815 816 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 817 #ifdef ENABLE_LE_SECURE_CONNECTIONS 818 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 819 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 820 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 821 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 822 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 823 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 824 }; 825 #endif 826 827 // default: just works 828 setup->sm_stk_generation_method = JUST_WORKS; 829 830 #ifdef ENABLE_LE_SECURE_CONNECTIONS 831 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 832 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 833 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 834 #else 835 setup->sm_use_secure_connections = 0; 836 #endif 837 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 838 839 840 // decide if OOB will be used based on SC vs. Legacy and oob flags 841 bool use_oob; 842 if (setup->sm_use_secure_connections){ 843 // In LE Secure Connections pairing, the out of band method is used if at least 844 // one device has the peer device's out of band authentication data available. 845 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; 846 } else { 847 // In LE legacy pairing, the out of band method is used if both the devices have 848 // the other device's out of band authentication data available. 849 use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; 850 } 851 if (use_oob){ 852 log_info("SM: have OOB data"); 853 log_info_key("OOB", setup->sm_tk); 854 setup->sm_stk_generation_method = OOB; 855 return; 856 } 857 858 // If both devices have not set the MITM option in the Authentication Requirements 859 // Flags, then the IO capabilities shall be ignored and the Just Works association 860 // model shall be used. 861 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 862 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 863 log_info("SM: MITM not required by both -> JUST WORKS"); 864 return; 865 } 866 867 // Reset TK as it has been setup in sm_init_setup 868 sm_reset_tk(); 869 870 // Also use just works if unknown io capabilites 871 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)){ 872 return; 873 } 874 875 // Otherwise the IO capabilities of the devices shall be used to determine the 876 // pairing method as defined in Table 2.4. 877 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 878 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 879 880 #ifdef ENABLE_LE_SECURE_CONNECTIONS 881 // table not define by default 882 if (setup->sm_use_secure_connections){ 883 generation_method = stk_generation_method_with_secure_connection; 884 } 885 #endif 886 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)]; 887 888 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 889 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); 890 } 891 892 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 893 int flags = 0; 894 if (key_set & SM_KEYDIST_ENC_KEY){ 895 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 896 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 897 } 898 if (key_set & SM_KEYDIST_ID_KEY){ 899 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 900 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 901 } 902 if (key_set & SM_KEYDIST_SIGN){ 903 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 904 } 905 return flags; 906 } 907 908 static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ 909 setup->sm_key_distribution_received_set = 0; 910 setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); 911 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); 912 setup->sm_key_distribution_sent_set = 0; 913 #ifdef ENABLE_LE_SIGNED_WRITE 914 setup->sm_le_device_index = -1; 915 #endif 916 } 917 918 // CSRK Key Lookup 919 920 921 static int sm_address_resolution_idle(void){ 922 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 923 } 924 925 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){ 926 (void)memcpy(sm_address_resolution_address, addr, 6); 927 sm_address_resolution_addr_type = addr_type; 928 sm_address_resolution_test = 0; 929 sm_address_resolution_mode = mode; 930 sm_address_resolution_context = context; 931 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 932 } 933 934 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 935 // check if already in list 936 btstack_linked_list_iterator_t it; 937 sm_lookup_entry_t * entry; 938 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 939 while(btstack_linked_list_iterator_has_next(&it)){ 940 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 941 if (entry->address_type != address_type) continue; 942 if (memcmp(entry->address, address, 6)) continue; 943 // already in list 944 return BTSTACK_BUSY; 945 } 946 entry = btstack_memory_sm_lookup_entry_get(); 947 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 948 entry->address_type = (bd_addr_type_t) address_type; 949 (void)memcpy(entry->address, address, 6); 950 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 951 sm_trigger_run(); 952 return 0; 953 } 954 955 // CMAC calculation using AES Engineq 956 #ifdef USE_CMAC_ENGINE 957 958 static void sm_cmac_done_trampoline(void * arg){ 959 UNUSED(arg); 960 sm_cmac_active = 0; 961 (*sm_cmac_done_callback)(sm_cmac_hash); 962 sm_trigger_run(); 963 } 964 965 int sm_cmac_ready(void){ 966 return sm_cmac_active == 0u; 967 } 968 #endif 969 970 #ifdef ENABLE_LE_SECURE_CONNECTIONS 971 // generic cmac calculation 972 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)){ 973 sm_cmac_active = 1; 974 sm_cmac_done_callback = done_callback; 975 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 976 } 977 #endif 978 979 // cmac for ATT Message signing 980 #ifdef ENABLE_LE_SIGNED_WRITE 981 982 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)){ 983 sm_cmac_active = 1; 984 sm_cmac_done_callback = done_callback; 985 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 986 } 987 988 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 989 if (offset >= sm_cmac_signed_write_message_len) { 990 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 991 return 0; 992 } 993 994 offset = sm_cmac_signed_write_message_len - 1 - offset; 995 996 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 997 if (offset < 3){ 998 return sm_cmac_signed_write_header[offset]; 999 } 1000 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 1001 if (offset < actual_message_len_incl_header){ 1002 return sm_cmac_signed_write_message[offset - 3]; 1003 } 1004 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 1005 } 1006 1007 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)){ 1008 // ATT Message Signing 1009 sm_cmac_signed_write_header[0] = opcode; 1010 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 1011 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 1012 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1013 sm_cmac_signed_write_message = message; 1014 sm_cmac_signed_write_message_len = total_message_len; 1015 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1016 } 1017 #endif 1018 1019 static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ 1020 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1021 uint8_t event[12]; 1022 sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1023 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1024 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1025 } 1026 1027 static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn){ 1028 uint8_t event[16]; 1029 uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); 1030 sm_setup_event_base(event, sizeof(event), SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, 1031 sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1032 event[11] = setup->sm_use_secure_connections ? 1 : 0; 1033 little_endian_store_32(event, 12, passkey); 1034 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 1035 } 1036 1037 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1038 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1039 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1040 sm_conn->sm_pairing_active = true; 1041 switch (setup->sm_stk_generation_method){ 1042 case PK_RESP_INPUT: 1043 if (IS_RESPONDER(sm_conn->sm_role)){ 1044 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1045 } else { 1046 sm_trigger_user_response_passkey(sm_conn); 1047 } 1048 break; 1049 case PK_INIT_INPUT: 1050 if (IS_RESPONDER(sm_conn->sm_role)){ 1051 sm_trigger_user_response_passkey(sm_conn); 1052 } else { 1053 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1054 } 1055 break; 1056 case PK_BOTH_INPUT: 1057 sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); 1058 break; 1059 case NUMERIC_COMPARISON: 1060 sm_trigger_user_response_basic(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); 1061 break; 1062 case JUST_WORKS: 1063 sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); 1064 break; 1065 case OOB: 1066 // client already provided OOB data, let's skip notification. 1067 break; 1068 default: 1069 btstack_assert(false); 1070 break; 1071 } 1072 } 1073 1074 static bool sm_key_distribution_all_received(void) { 1075 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); 1076 return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; 1077 } 1078 1079 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1080 if (sm_active_connection_handle == con_handle){ 1081 sm_timeout_stop(); 1082 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1083 log_info("sm: connection 0x%x released setup context", con_handle); 1084 1085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1086 // generate new ec key after each pairing (that used it) 1087 if (setup->sm_use_secure_connections){ 1088 sm_ec_generate_new_key(); 1089 } 1090 #endif 1091 } 1092 } 1093 1094 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1095 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1096 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1097 sm_done_for_handle(connection->sm_handle); 1098 } 1099 1100 static int sm_key_distribution_flags_for_auth_req(void){ 1101 1102 int flags = SM_KEYDIST_ID_KEY; 1103 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1104 // encryption and signing information only if bonding requested 1105 flags |= SM_KEYDIST_ENC_KEY; 1106 #ifdef ENABLE_LE_SIGNED_WRITE 1107 flags |= SM_KEYDIST_SIGN; 1108 #endif 1109 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1110 // LinkKey for CTKD requires SC 1111 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1112 flags |= SM_KEYDIST_LINK_KEY; 1113 } 1114 #endif 1115 } 1116 return flags; 1117 } 1118 1119 static void sm_reset_setup(void){ 1120 // fill in sm setup 1121 setup->sm_state_vars = 0; 1122 setup->sm_keypress_notification = 0; 1123 setup->sm_have_oob_data = 0; 1124 sm_reset_tk(); 1125 } 1126 1127 static void sm_init_setup(sm_connection_t * sm_conn){ 1128 // fill in sm setup 1129 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1130 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1131 1132 // query client for Legacy Pairing OOB data 1133 if (sm_get_oob_data != NULL) { 1134 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1135 } 1136 1137 // if available and SC supported, also ask for SC OOB Data 1138 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1139 memset(setup->sm_ra, 0, 16); 1140 memset(setup->sm_rb, 0, 16); 1141 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1142 if (sm_get_sc_oob_data != NULL){ 1143 if (IS_RESPONDER(sm_conn->sm_role)){ 1144 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1145 sm_conn->sm_peer_addr_type, 1146 sm_conn->sm_peer_address, 1147 setup->sm_peer_confirm, 1148 setup->sm_ra); 1149 } else { 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_rb); 1155 } 1156 } else { 1157 setup->sm_have_oob_data = 0; 1158 } 1159 } 1160 #endif 1161 1162 sm_pairing_packet_t * local_packet; 1163 if (IS_RESPONDER(sm_conn->sm_role)){ 1164 // slave 1165 local_packet = &setup->sm_s_pres; 1166 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1167 setup->sm_s_addr_type = sm_conn->sm_own_addr_type; 1168 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1169 (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); 1170 } else { 1171 // master 1172 local_packet = &setup->sm_m_preq; 1173 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1174 setup->sm_m_addr_type = sm_conn->sm_own_addr_type; 1175 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1176 (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); 1177 1178 uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1179 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1180 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1181 } 1182 1183 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1184 uint8_t max_encryption_key_size = sm_max_encryption_key_size; 1185 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1186 // enable SC for SC only mode 1187 if (sm_sc_only_mode){ 1188 auth_req |= SM_AUTHREQ_SECURE_CONNECTION; 1189 max_encryption_key_size = 16; 1190 } 1191 #endif 1192 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1193 // set CT2 if SC + Bonding + CTKD 1194 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1195 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1196 auth_req |= SM_AUTHREQ_CT2; 1197 } 1198 #endif 1199 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1200 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1201 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1202 sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); 1203 } 1204 1205 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1206 1207 sm_pairing_packet_t * remote_packet; 1208 uint8_t keys_to_send; 1209 uint8_t keys_to_receive; 1210 if (IS_RESPONDER(sm_conn->sm_role)){ 1211 // slave / responder 1212 remote_packet = &setup->sm_m_preq; 1213 keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1214 keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); 1215 } else { 1216 // master / initiator 1217 remote_packet = &setup->sm_s_pres; 1218 keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1219 keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); 1220 } 1221 1222 // check key size 1223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1224 // SC Only mandates 128 bit key size 1225 if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { 1226 return SM_REASON_ENCRYPTION_KEY_SIZE; 1227 } 1228 #endif 1229 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1230 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1231 1232 // decide on STK generation method / SC 1233 sm_setup_tk(); 1234 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1235 1236 // check if STK generation method is acceptable by client 1237 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1238 1239 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1240 // Check LE SC Only mode 1241 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1242 log_info("SC Only mode active but SC not possible"); 1243 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1244 } 1245 1246 // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection 1247 if (setup->sm_use_secure_connections){ 1248 keys_to_send &= ~SM_KEYDIST_ENC_KEY; 1249 keys_to_receive &= ~SM_KEYDIST_ENC_KEY; 1250 } 1251 #endif 1252 1253 // identical to responder 1254 sm_setup_key_distribution(keys_to_send, keys_to_receive); 1255 1256 // JUST WORKS doens't provide authentication 1257 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1258 1259 return 0; 1260 } 1261 1262 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1263 1264 // cache and reset context 1265 int matched_device_id = sm_address_resolution_test; 1266 address_resolution_mode_t mode = sm_address_resolution_mode; 1267 void * context = sm_address_resolution_context; 1268 1269 // reset context 1270 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1271 sm_address_resolution_context = NULL; 1272 sm_address_resolution_test = -1; 1273 hci_con_handle_t con_handle = 0; 1274 1275 sm_connection_t * sm_connection; 1276 sm_key_t ltk; 1277 bool have_ltk; 1278 #ifdef ENABLE_LE_CENTRAL 1279 bool trigger_pairing; 1280 #endif 1281 switch (mode){ 1282 case ADDRESS_RESOLUTION_GENERAL: 1283 break; 1284 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1285 sm_connection = (sm_connection_t *) context; 1286 con_handle = sm_connection->sm_handle; 1287 1288 // have ltk -> start encryption / send security request 1289 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1290 // "When a bond has been created between two devices, any reconnection should result in the local device 1291 // enabling or requesting encryption with the remote device before initiating any service request." 1292 1293 switch (event){ 1294 case ADDRESS_RESOLUTION_SUCCEEDED: 1295 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1296 sm_connection->sm_le_db_index = matched_device_id; 1297 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1298 1299 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1300 have_ltk = !sm_is_null_key(ltk); 1301 1302 if (sm_connection->sm_role) { 1303 #ifdef ENABLE_LE_PERIPHERAL 1304 // IRK required before, continue 1305 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1306 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1307 break; 1308 } 1309 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ 1310 sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 1311 break; 1312 } 1313 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1314 sm_connection->sm_pairing_requested = 0; 1315 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1316 // trigger security request for Proactive Authentication if LTK available 1317 trigger_security_request = trigger_security_request || have_ltk; 1318 #endif 1319 1320 log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", 1321 sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); 1322 1323 if (trigger_security_request){ 1324 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1325 if (have_ltk){ 1326 sm_reencryption_started(sm_connection); 1327 } else { 1328 sm_pairing_started(sm_connection); 1329 } 1330 sm_trigger_run(); 1331 } 1332 #endif 1333 } else { 1334 1335 #ifdef ENABLE_LE_CENTRAL 1336 // check if pairing already requested and reset requests 1337 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1338 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1339 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); 1340 sm_connection->sm_security_request_received = 0; 1341 sm_connection->sm_pairing_requested = 0; 1342 bool trigger_reencryption = false; 1343 1344 if (have_ltk){ 1345 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1346 trigger_reencryption = true; 1347 #else 1348 if (trigger_pairing){ 1349 trigger_reencryption = true; 1350 } else { 1351 log_info("central: defer enabling encryption for bonded device"); 1352 } 1353 #endif 1354 } 1355 1356 if (trigger_reencryption){ 1357 log_info("central: enable encryption for bonded device"); 1358 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1359 break; 1360 } 1361 1362 // pairing_request -> send pairing request 1363 if (trigger_pairing){ 1364 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1365 break; 1366 } 1367 #endif 1368 } 1369 break; 1370 case ADDRESS_RESOLUTION_FAILED: 1371 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1372 if (sm_connection->sm_role) { 1373 #ifdef ENABLE_LE_PERIPHERAL 1374 // LTK request received before, IRK required -> negative LTK reply 1375 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1376 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1377 } 1378 // send security request if requested 1379 bool trigger_security_request = (sm_connection->sm_pairing_requested != 0) || (sm_slave_request_security != 0); 1380 sm_connection->sm_pairing_requested = 0; 1381 if (trigger_security_request){ 1382 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1383 sm_pairing_started(sm_connection); 1384 } 1385 break; 1386 #endif 1387 } 1388 #ifdef ENABLE_LE_CENTRAL 1389 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1390 sm_connection->sm_security_request_received = 0; 1391 sm_connection->sm_pairing_requested = 0; 1392 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1393 #endif 1394 break; 1395 1396 default: 1397 btstack_assert(false); 1398 break; 1399 } 1400 break; 1401 default: 1402 break; 1403 } 1404 1405 switch (event){ 1406 case ADDRESS_RESOLUTION_SUCCEEDED: 1407 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1408 break; 1409 case ADDRESS_RESOLUTION_FAILED: 1410 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1411 break; 1412 default: 1413 btstack_assert(false); 1414 break; 1415 } 1416 } 1417 1418 static void sm_store_bonding_information(sm_connection_t * sm_conn){ 1419 int le_db_index = -1; 1420 1421 // lookup device based on IRK 1422 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1423 int i; 1424 for (i=0; i < le_device_db_max_count(); i++){ 1425 sm_key_t irk; 1426 bd_addr_t address; 1427 int address_type = BD_ADDR_TYPE_UNKNOWN; 1428 le_device_db_info(i, &address_type, address, irk); 1429 // skip unused entries 1430 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1431 // compare Identity Address 1432 if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; 1433 // compare Identity Resolving Key 1434 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1435 1436 log_info("sm: device found for IRK, updating"); 1437 le_db_index = i; 1438 break; 1439 } 1440 } else { 1441 // assert IRK is set to zero 1442 memset(setup->sm_peer_irk, 0, 16); 1443 } 1444 1445 // if not found, lookup via public address if possible 1446 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1447 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1448 int i; 1449 for (i=0; i < le_device_db_max_count(); i++){ 1450 bd_addr_t address; 1451 int address_type = BD_ADDR_TYPE_UNKNOWN; 1452 le_device_db_info(i, &address_type, address, NULL); 1453 // skip unused entries 1454 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1455 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1456 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1457 log_info("sm: device found for public address, updating"); 1458 le_db_index = i; 1459 break; 1460 } 1461 } 1462 } 1463 1464 // if not found, add to db 1465 bool new_to_le_device_db = false; 1466 if (le_db_index < 0) { 1467 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1468 new_to_le_device_db = true; 1469 } 1470 1471 if (le_db_index >= 0){ 1472 1473 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1474 if (!new_to_le_device_db){ 1475 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1476 } 1477 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1478 #else 1479 UNUSED(new_to_le_device_db); 1480 #endif 1481 1482 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1483 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1484 sm_conn->sm_le_db_index = le_db_index; 1485 1486 #ifdef ENABLE_LE_SIGNED_WRITE 1487 // store local CSRK 1488 setup->sm_le_device_index = le_db_index; 1489 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1490 log_info("sm: store local CSRK"); 1491 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1492 le_device_db_local_counter_set(le_db_index, 0); 1493 } 1494 1495 // store remote CSRK 1496 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1497 log_info("sm: store remote CSRK"); 1498 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1499 le_device_db_remote_counter_set(le_db_index, 0); 1500 } 1501 #endif 1502 // store encryption information for secure connections: LTK generated by ECDH 1503 if (setup->sm_use_secure_connections){ 1504 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1505 uint8_t zero_rand[8]; 1506 memset(zero_rand, 0, 8); 1507 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1508 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1509 } 1510 1511 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1512 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1513 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1514 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1515 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1516 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1517 1518 } 1519 } 1520 } 1521 1522 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1523 sm_conn->sm_pairing_failed_reason = reason; 1524 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1525 } 1526 1527 static int sm_lookup_by_address(void) { 1528 int i; 1529 for (i=0; i < le_device_db_max_count(); i++){ 1530 bd_addr_t address; 1531 int address_type = BD_ADDR_TYPE_UNKNOWN; 1532 le_device_db_info(i, &address_type, address, NULL); 1533 // skip unused entries 1534 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1535 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1536 return i; 1537 } 1538 } 1539 return -1; 1540 } 1541 1542 static void sm_remove_le_device_db_entry(uint16_t i) { 1543 le_device_db_remove(i); 1544 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1545 // to remove an entry from the resolving list requires its identity address, which was already deleted 1546 // fully reload resolving list instead 1547 gap_load_resolving_list_from_le_device_db(); 1548 #endif 1549 } 1550 1551 static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){ 1552 // if identity is provided, abort if we have bonding with same address but different irk 1553 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1554 int index = sm_lookup_by_address(); 1555 if (index >= 0){ 1556 sm_key_t irk; 1557 le_device_db_info(index, NULL, NULL, irk); 1558 if (memcmp(irk, setup->sm_peer_irk, 16) != 0){ 1559 // IRK doesn't match, delete bonding information 1560 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); 1561 sm_remove_le_device_db_entry(index); 1562 } 1563 } 1564 } 1565 return 0; 1566 } 1567 1568 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1569 1570 // abort pairing if received keys are not valid 1571 uint8_t reason = sm_key_distribution_validate_received(sm_conn); 1572 if (reason != 0){ 1573 sm_pairing_error(sm_conn, reason); 1574 return; 1575 } 1576 1577 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1578 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1579 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1580 & SM_AUTHREQ_BONDING ) != 0u; 1581 1582 if (bonding_enabled){ 1583 sm_store_bonding_information(sm_conn); 1584 } else { 1585 log_info("Ignoring received keys, bonding not enabled"); 1586 } 1587 } 1588 1589 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1590 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1591 } 1592 1593 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1594 1595 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1596 static int sm_passkey_used(stk_generation_method_t method); 1597 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1598 1599 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1600 if (setup->sm_stk_generation_method == OOB){ 1601 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1602 } else { 1603 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); 1604 } 1605 } 1606 1607 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1608 if (IS_RESPONDER(sm_conn->sm_role)){ 1609 // Responder 1610 if (setup->sm_stk_generation_method == OOB){ 1611 // generate Nb 1612 log_info("Generate Nb"); 1613 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); 1614 } else { 1615 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1616 } 1617 } else { 1618 // Initiator role 1619 switch (setup->sm_stk_generation_method){ 1620 case JUST_WORKS: 1621 sm_sc_prepare_dhkey_check(sm_conn); 1622 break; 1623 1624 case NUMERIC_COMPARISON: 1625 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1626 break; 1627 case PK_INIT_INPUT: 1628 case PK_RESP_INPUT: 1629 case PK_BOTH_INPUT: 1630 if (setup->sm_passkey_bit < 20u) { 1631 sm_sc_start_calculating_local_confirm(sm_conn); 1632 } else { 1633 sm_sc_prepare_dhkey_check(sm_conn); 1634 } 1635 break; 1636 case OOB: 1637 sm_sc_prepare_dhkey_check(sm_conn); 1638 break; 1639 default: 1640 btstack_assert(false); 1641 break; 1642 } 1643 } 1644 } 1645 1646 static void sm_sc_cmac_done(uint8_t * hash){ 1647 log_info("sm_sc_cmac_done: "); 1648 log_info_hexdump(hash, 16); 1649 1650 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1651 sm_sc_oob_state = SM_SC_OOB_IDLE; 1652 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1653 return; 1654 } 1655 1656 sm_connection_t * sm_conn = sm_cmac_connection; 1657 sm_cmac_connection = NULL; 1658 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1659 link_key_type_t link_key_type; 1660 #endif 1661 1662 switch (sm_conn->sm_engine_state){ 1663 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1664 (void)memcpy(setup->sm_local_confirm, hash, 16); 1665 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1666 break; 1667 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1668 // check 1669 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1670 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1671 break; 1672 } 1673 sm_sc_state_after_receiving_random(sm_conn); 1674 break; 1675 case SM_SC_W4_CALCULATE_G2: { 1676 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1677 big_endian_store_32(setup->sm_tk, 12, vab); 1678 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1679 sm_trigger_user_response(sm_conn); 1680 break; 1681 } 1682 case SM_SC_W4_CALCULATE_F5_SALT: 1683 (void)memcpy(setup->sm_t, hash, 16); 1684 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1685 break; 1686 case SM_SC_W4_CALCULATE_F5_MACKEY: 1687 (void)memcpy(setup->sm_mackey, hash, 16); 1688 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1689 break; 1690 case SM_SC_W4_CALCULATE_F5_LTK: 1691 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1692 // Errata Service Release to the Bluetooth Specification: ESR09 1693 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1694 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1695 (void)memcpy(setup->sm_ltk, hash, 16); 1696 (void)memcpy(setup->sm_local_ltk, hash, 16); 1697 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1698 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1699 break; 1700 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1701 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1702 if (IS_RESPONDER(sm_conn->sm_role)){ 1703 // responder 1704 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1705 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1706 } else { 1707 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1708 } 1709 } else { 1710 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1711 } 1712 break; 1713 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1714 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1715 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1716 break; 1717 } 1718 if (IS_RESPONDER(sm_conn->sm_role)){ 1719 // responder 1720 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1721 } else { 1722 // initiator 1723 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1724 } 1725 break; 1726 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1727 case SM_SC_W4_CALCULATE_ILK: 1728 (void)memcpy(setup->sm_t, hash, 16); 1729 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1730 break; 1731 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1732 reverse_128(hash, setup->sm_t); 1733 link_key_type = sm_conn->sm_connection_authenticated ? 1734 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1735 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1736 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1737 if (IS_RESPONDER(sm_conn->sm_role)){ 1738 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1739 } else { 1740 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1741 } 1742 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1743 sm_done_for_handle(sm_conn->sm_handle); 1744 break; 1745 case SM_BR_EDR_W4_CALCULATE_ILK: 1746 (void)memcpy(setup->sm_t, hash, 16); 1747 sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; 1748 break; 1749 case SM_BR_EDR_W4_CALCULATE_LE_LTK: 1750 log_info("Derived LE LTK from BR/EDR Link Key"); 1751 log_info_key("Link Key", hash); 1752 (void)memcpy(setup->sm_ltk, hash, 16); 1753 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1754 sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1755 sm_store_bonding_information(sm_conn); 1756 sm_done_for_handle(sm_conn->sm_handle); 1757 break; 1758 #endif 1759 default: 1760 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1761 break; 1762 } 1763 sm_trigger_run(); 1764 } 1765 1766 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){ 1767 const uint16_t message_len = 65; 1768 sm_cmac_connection = sm_conn; 1769 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1770 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1771 sm_cmac_sc_buffer[64] = z; 1772 log_info("f4 key"); 1773 log_info_hexdump(x, 16); 1774 log_info("f4 message"); 1775 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1776 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1777 } 1778 1779 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1780 static const uint8_t f5_length[] = { 0x01, 0x00}; 1781 1782 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1783 1784 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1785 1786 log_info("f5_calculate_salt"); 1787 // calculate salt for f5 1788 const uint16_t message_len = 32; 1789 sm_cmac_connection = sm_conn; 1790 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1791 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1792 } 1793 1794 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){ 1795 const uint16_t message_len = 53; 1796 sm_cmac_connection = sm_conn; 1797 1798 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1799 sm_cmac_sc_buffer[0] = 0; 1800 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1801 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1802 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1803 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1804 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1805 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1806 log_info("f5 key"); 1807 log_info_hexdump(t, 16); 1808 log_info("f5 message for MacKey"); 1809 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1810 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1811 } 1812 1813 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1814 sm_key56_t bd_addr_master, bd_addr_slave; 1815 bd_addr_master[0] = setup->sm_m_addr_type; 1816 bd_addr_slave[0] = setup->sm_s_addr_type; 1817 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1818 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1819 if (IS_RESPONDER(sm_conn->sm_role)){ 1820 // responder 1821 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1822 } else { 1823 // initiator 1824 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1825 } 1826 } 1827 1828 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1829 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1830 const uint16_t message_len = 53; 1831 sm_cmac_connection = sm_conn; 1832 sm_cmac_sc_buffer[0] = 1; 1833 // 1..52 setup before 1834 log_info("f5 key"); 1835 log_info_hexdump(t, 16); 1836 log_info("f5 message for LTK"); 1837 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1838 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1839 } 1840 1841 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1842 f5_ltk(sm_conn, setup->sm_t); 1843 } 1844 1845 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){ 1846 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1847 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1848 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1849 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1850 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1851 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1852 } 1853 1854 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1855 const uint16_t message_len = 65; 1856 sm_cmac_connection = sm_conn; 1857 log_info("f6 key"); 1858 log_info_hexdump(w, 16); 1859 log_info("f6 message"); 1860 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1861 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1862 } 1863 1864 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1865 // - U is 256 bits 1866 // - V is 256 bits 1867 // - X is 128 bits 1868 // - Y is 128 bits 1869 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){ 1870 const uint16_t message_len = 80; 1871 sm_cmac_connection = sm_conn; 1872 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1873 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1874 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1875 log_info("g2 key"); 1876 log_info_hexdump(x, 16); 1877 log_info("g2 message"); 1878 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1879 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1880 } 1881 1882 static void g2_calculate(sm_connection_t * sm_conn) { 1883 // calc Va if numeric comparison 1884 if (IS_RESPONDER(sm_conn->sm_role)){ 1885 // responder 1886 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1887 } else { 1888 // initiator 1889 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1890 } 1891 } 1892 1893 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1894 uint8_t z = 0; 1895 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1896 // some form of passkey 1897 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1898 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1899 setup->sm_passkey_bit++; 1900 } 1901 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1902 } 1903 1904 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1905 // OOB 1906 if (setup->sm_stk_generation_method == OOB){ 1907 if (IS_RESPONDER(sm_conn->sm_role)){ 1908 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1909 } else { 1910 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1911 } 1912 return; 1913 } 1914 1915 uint8_t z = 0; 1916 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1917 // some form of passkey 1918 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1919 // sm_passkey_bit was increased before sending confirm value 1920 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1921 } 1922 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1923 } 1924 1925 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1926 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1927 1928 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1929 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1930 return; 1931 } else { 1932 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1933 } 1934 } 1935 1936 static void sm_sc_dhkey_calculated(void * arg){ 1937 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1938 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1939 if (sm_conn == NULL) return; 1940 1941 log_info("dhkey"); 1942 log_info_hexdump(&setup->sm_dhkey[0], 32); 1943 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1944 // trigger next step 1945 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1946 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1947 } 1948 sm_trigger_run(); 1949 } 1950 1951 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1952 // calculate DHKCheck 1953 sm_key56_t bd_addr_master, bd_addr_slave; 1954 bd_addr_master[0] = setup->sm_m_addr_type; 1955 bd_addr_slave[0] = setup->sm_s_addr_type; 1956 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1957 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1958 uint8_t iocap_a[3]; 1959 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1960 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1961 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1962 uint8_t iocap_b[3]; 1963 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1964 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1965 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1966 if (IS_RESPONDER(sm_conn->sm_role)){ 1967 // responder 1968 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1969 f6_engine(sm_conn, setup->sm_mackey); 1970 } else { 1971 // initiator 1972 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1973 f6_engine(sm_conn, setup->sm_mackey); 1974 } 1975 } 1976 1977 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1978 // validate E = f6() 1979 sm_key56_t bd_addr_master, bd_addr_slave; 1980 bd_addr_master[0] = setup->sm_m_addr_type; 1981 bd_addr_slave[0] = setup->sm_s_addr_type; 1982 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1983 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1984 1985 uint8_t iocap_a[3]; 1986 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1987 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1988 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1989 uint8_t iocap_b[3]; 1990 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1991 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1992 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1993 if (IS_RESPONDER(sm_conn->sm_role)){ 1994 // responder 1995 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1996 f6_engine(sm_conn, setup->sm_mackey); 1997 } else { 1998 // initiator 1999 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2000 f6_engine(sm_conn, setup->sm_mackey); 2001 } 2002 } 2003 2004 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2005 2006 // 2007 // Link Key Conversion Function h6 2008 // 2009 // h6(W, keyID) = AES-CMAC_W(keyID) 2010 // - W is 128 bits 2011 // - keyID is 32 bits 2012 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 2013 const uint16_t message_len = 4; 2014 sm_cmac_connection = sm_conn; 2015 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 2016 log_info("h6 key"); 2017 log_info_hexdump(w, 16); 2018 log_info("h6 message"); 2019 log_info_hexdump(sm_cmac_sc_buffer, message_len); 2020 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 2021 } 2022 // 2023 // Link Key Conversion Function h7 2024 // 2025 // h7(SALT, W) = AES-CMAC_SALT(W) 2026 // - SALT is 128 bits 2027 // - W is 128 bits 2028 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 2029 const uint16_t message_len = 16; 2030 sm_cmac_connection = sm_conn; 2031 log_info("h7 key"); 2032 log_info_hexdump(salt, 16); 2033 log_info("h7 message"); 2034 log_info_hexdump(w, 16); 2035 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 2036 } 2037 2038 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 2039 // Errata Service Release to the Bluetooth Specification: ESR09 2040 // E6405 – Cross transport key derivation from a key of size less than 128 bits 2041 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 2042 2043 static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2044 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 2045 } 2046 2047 static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2048 h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" 2049 } 2050 2051 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 2052 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 2053 } 2054 2055 static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ 2056 h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" 2057 } 2058 2059 static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ 2060 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 2061 h7_engine(sm_conn, salt, setup->sm_local_ltk); 2062 } 2063 2064 static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ 2065 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" 2066 h7_engine(sm_conn, salt, setup->sm_link_key); 2067 } 2068 2069 static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ 2070 hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); 2071 btstack_assert(hci_connection != NULL); 2072 reverse_128(hci_connection->link_key, setup->sm_link_key); 2073 setup->sm_link_key_type = hci_connection->link_key_type; 2074 } 2075 2076 static void sm_ctkd_start_from_br_edr(sm_connection_t * connection){ 2077 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; 2078 connection->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; 2079 } 2080 2081 #endif 2082 2083 #endif 2084 2085 // key management legacy connections: 2086 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 2087 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 2088 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 2089 // - responder reconnects: responder uses LTK receveived from master 2090 2091 // key management secure connections: 2092 // - both devices store same LTK from ECDH key exchange. 2093 2094 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 2095 static void sm_load_security_info(sm_connection_t * sm_connection){ 2096 int encryption_key_size; 2097 int authenticated; 2098 int authorized; 2099 int secure_connection; 2100 2101 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 2102 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 2103 &encryption_key_size, &authenticated, &authorized, &secure_connection); 2104 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); 2105 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 2106 sm_connection->sm_connection_authenticated = authenticated; 2107 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 2108 sm_connection->sm_connection_sc = secure_connection; 2109 } 2110 #endif 2111 2112 #ifdef ENABLE_LE_PERIPHERAL 2113 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 2114 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 2115 setup->sm_local_ediv = sm_connection->sm_local_ediv; 2116 // re-establish used key encryption size 2117 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2118 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 2119 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 2120 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 2121 // Legacy paring -> not SC 2122 sm_connection->sm_connection_sc = 0; 2123 log_info("sm: received ltk request with key size %u, authenticated %u", 2124 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 2125 } 2126 #endif 2127 2128 // distributed key generation 2129 static bool sm_run_dpkg(void){ 2130 switch (dkg_state){ 2131 case DKG_CALC_IRK: 2132 // already busy? 2133 if (sm_aes128_state == SM_AES128_IDLE) { 2134 log_info("DKG_CALC_IRK started"); 2135 // IRK = d1(IR, 1, 0) 2136 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 2137 sm_aes128_state = SM_AES128_ACTIVE; 2138 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 2139 return true; 2140 } 2141 break; 2142 case DKG_CALC_DHK: 2143 // already busy? 2144 if (sm_aes128_state == SM_AES128_IDLE) { 2145 log_info("DKG_CALC_DHK started"); 2146 // DHK = d1(IR, 3, 0) 2147 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2148 sm_aes128_state = SM_AES128_ACTIVE; 2149 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2150 return true; 2151 } 2152 break; 2153 default: 2154 break; 2155 } 2156 return false; 2157 } 2158 2159 // random address updates 2160 static bool sm_run_rau(void){ 2161 switch (rau_state){ 2162 case RAU_GET_RANDOM: 2163 rau_state = RAU_W4_RANDOM; 2164 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2165 return true; 2166 case RAU_GET_ENC: 2167 // already busy? 2168 if (sm_aes128_state == SM_AES128_IDLE) { 2169 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2170 sm_aes128_state = SM_AES128_ACTIVE; 2171 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2172 return true; 2173 } 2174 break; 2175 default: 2176 break; 2177 } 2178 return false; 2179 } 2180 2181 // CSRK Lookup 2182 static bool sm_run_csrk(void){ 2183 btstack_linked_list_iterator_t it; 2184 2185 // -- if csrk lookup ready, find connection that require csrk lookup 2186 if (sm_address_resolution_idle()){ 2187 hci_connections_get_iterator(&it); 2188 while(btstack_linked_list_iterator_has_next(&it)){ 2189 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2190 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2191 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2192 // and start lookup 2193 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); 2194 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2195 break; 2196 } 2197 } 2198 } 2199 2200 // -- if csrk lookup ready, resolved addresses for received addresses 2201 if (sm_address_resolution_idle()) { 2202 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2203 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2204 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2205 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2206 btstack_memory_sm_lookup_entry_free(entry); 2207 } 2208 } 2209 2210 // -- Continue with device lookup by public or resolvable private address 2211 if (!sm_address_resolution_idle()){ 2212 while (sm_address_resolution_test < le_device_db_max_count()){ 2213 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2214 bd_addr_t addr; 2215 sm_key_t irk; 2216 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2217 2218 // skip unused entries 2219 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2220 sm_address_resolution_test++; 2221 continue; 2222 } 2223 2224 log_info("LE Device Lookup: device %u of %u", sm_address_resolution_test, le_device_db_max_count()); 2225 2226 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2227 log_info("LE Device Lookup: found by { addr_type, address} "); 2228 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2229 break; 2230 } 2231 2232 // if connection type is public, it must be a different one 2233 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2234 sm_address_resolution_test++; 2235 continue; 2236 } 2237 2238 // skip AH if no IRK 2239 if (sm_is_null_key(irk)){ 2240 sm_address_resolution_test++; 2241 continue; 2242 } 2243 2244 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2245 2246 log_info("LE Device Lookup: calculate AH"); 2247 log_info_key("IRK", irk); 2248 2249 (void)memcpy(sm_aes128_key, irk, 16); 2250 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2251 sm_address_resolution_ah_calculation_active = 1; 2252 sm_aes128_state = SM_AES128_ACTIVE; 2253 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2254 return true; 2255 } 2256 2257 if (sm_address_resolution_test >= le_device_db_max_count()){ 2258 log_info("LE Device Lookup: not found"); 2259 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2260 } 2261 } 2262 return false; 2263 } 2264 2265 // SC OOB 2266 static bool sm_run_oob(void){ 2267 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2268 switch (sm_sc_oob_state){ 2269 case SM_SC_OOB_W2_CALC_CONFIRM: 2270 if (!sm_cmac_ready()) break; 2271 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2272 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2273 return true; 2274 default: 2275 break; 2276 } 2277 #endif 2278 return false; 2279 } 2280 2281 static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ 2282 l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); 2283 } 2284 2285 // handle basic actions that don't requires the full context 2286 static bool sm_run_basic(void){ 2287 btstack_linked_list_iterator_t it; 2288 hci_connections_get_iterator(&it); 2289 while(btstack_linked_list_iterator_has_next(&it)){ 2290 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2291 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2292 switch(sm_connection->sm_engine_state){ 2293 2294 // general 2295 case SM_GENERAL_SEND_PAIRING_FAILED: { 2296 uint8_t buffer[2]; 2297 buffer[0] = SM_CODE_PAIRING_FAILED; 2298 buffer[1] = sm_connection->sm_pairing_failed_reason; 2299 sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2300 sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); 2301 sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); 2302 sm_done_for_handle(sm_connection->sm_handle); 2303 break; 2304 } 2305 2306 // responder side 2307 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2308 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2309 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2310 return true; 2311 2312 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2313 case SM_SC_RECEIVED_LTK_REQUEST: 2314 switch (sm_connection->sm_irk_lookup_state){ 2315 case IRK_LOOKUP_FAILED: 2316 log_info("LTK Request: IRK Lookup Failed)"); 2317 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2318 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2319 return true; 2320 default: 2321 break; 2322 } 2323 break; 2324 #endif 2325 default: 2326 break; 2327 } 2328 } 2329 return false; 2330 } 2331 2332 static void sm_run_activate_connection(void){ 2333 // Find connections that requires setup context and make active if no other is locked 2334 btstack_linked_list_iterator_t it; 2335 hci_connections_get_iterator(&it); 2336 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2337 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2338 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2339 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2340 bool done = true; 2341 int err; 2342 UNUSED(err); 2343 2344 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2345 // assert ec key is ready 2346 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2347 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2348 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2349 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2350 sm_ec_generate_new_key(); 2351 } 2352 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2353 continue; 2354 } 2355 } 2356 #endif 2357 2358 switch (sm_connection->sm_engine_state) { 2359 #ifdef ENABLE_LE_PERIPHERAL 2360 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2361 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2362 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2363 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2364 case SM_SC_RECEIVED_LTK_REQUEST: 2365 #endif 2366 #endif 2367 #ifdef ENABLE_LE_CENTRAL 2368 case SM_INITIATOR_PH4_HAS_LTK: 2369 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2370 #endif 2371 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2372 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 2373 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 2374 #endif 2375 // just lock context 2376 break; 2377 default: 2378 done = false; 2379 break; 2380 } 2381 if (done){ 2382 sm_active_connection_handle = sm_connection->sm_handle; 2383 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); 2384 } 2385 } 2386 } 2387 2388 static void sm_run_send_keypress_notification(sm_connection_t * connection){ 2389 int i; 2390 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2391 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2392 uint8_t action = 0; 2393 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2394 if (flags & (1u<<i)){ 2395 bool clear_flag = true; 2396 switch (i){ 2397 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2398 case SM_KEYPRESS_PASSKEY_CLEARED: 2399 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2400 default: 2401 break; 2402 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2403 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2404 num_actions--; 2405 clear_flag = num_actions == 0u; 2406 break; 2407 } 2408 if (clear_flag){ 2409 flags &= ~(1<<i); 2410 } 2411 action = i; 2412 break; 2413 } 2414 } 2415 setup->sm_keypress_notification = (num_actions << 5) | flags; 2416 2417 // send keypress notification 2418 uint8_t buffer[2]; 2419 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2420 buffer[1] = action; 2421 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2422 2423 // try 2424 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2425 } 2426 2427 static void sm_run_distribute_keys(sm_connection_t * connection){ 2428 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2429 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2430 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2431 uint8_t buffer[17]; 2432 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2433 reverse_128(setup->sm_ltk, &buffer[1]); 2434 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2435 sm_timeout_reset(connection); 2436 return; 2437 } 2438 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2439 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2440 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2441 uint8_t buffer[11]; 2442 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2443 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2444 reverse_64(setup->sm_local_rand, &buffer[3]); 2445 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2446 sm_timeout_reset(connection); 2447 return; 2448 } 2449 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2450 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2451 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2452 uint8_t buffer[17]; 2453 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2454 reverse_128(sm_persistent_irk, &buffer[1]); 2455 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2456 sm_timeout_reset(connection); 2457 return; 2458 } 2459 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2460 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2461 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2462 bd_addr_t local_address; 2463 uint8_t buffer[8]; 2464 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2465 switch (gap_random_address_get_mode()){ 2466 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2467 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2468 // public or static random 2469 gap_le_get_own_address(&buffer[1], local_address); 2470 break; 2471 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2472 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2473 // fallback to public 2474 gap_local_bd_addr(local_address); 2475 buffer[1] = 0; 2476 break; 2477 default: 2478 btstack_assert(false); 2479 break; 2480 } 2481 reverse_bd_addr(local_address, &buffer[2]); 2482 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2483 sm_timeout_reset(connection); 2484 return; 2485 } 2486 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2487 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2488 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2489 2490 #ifdef ENABLE_LE_SIGNED_WRITE 2491 // hack to reproduce test runs 2492 if (test_use_fixed_local_csrk){ 2493 memset(setup->sm_local_csrk, 0xcc, 16); 2494 } 2495 2496 // store local CSRK 2497 if (setup->sm_le_device_index >= 0){ 2498 log_info("sm: store local CSRK"); 2499 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2500 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2501 } 2502 #endif 2503 2504 uint8_t buffer[17]; 2505 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2506 reverse_128(setup->sm_local_csrk, &buffer[1]); 2507 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2508 sm_timeout_reset(connection); 2509 return; 2510 } 2511 btstack_assert(false); 2512 } 2513 2514 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2515 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2516 // requirements to derive link key from LE: 2517 // - use secure connections 2518 if (setup->sm_use_secure_connections == 0) return false; 2519 // - bonding needs to be enabled: 2520 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; 2521 if (!bonding_enabled) return false; 2522 // - need identity address / public addr 2523 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); 2524 if (!have_identity_address_info) return false; 2525 // - 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) 2526 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2527 // If SC is authenticated, we consider it safe to overwrite a stored key. 2528 // 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. 2529 uint8_t link_key[16]; 2530 link_key_type_t link_key_type; 2531 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2532 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); 2533 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2534 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2535 return false; 2536 } 2537 // get started (all of the above are true) 2538 return true; 2539 #else 2540 UNUSED(sm_connection); 2541 return false; 2542 #endif 2543 } 2544 2545 static void sm_key_distribution_complete_responder(sm_connection_t * connection){ 2546 if (sm_ctkd_from_le(connection)){ 2547 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; 2548 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2549 } else { 2550 connection->sm_engine_state = SM_RESPONDER_IDLE; 2551 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2552 sm_done_for_handle(connection->sm_handle); 2553 } 2554 } 2555 2556 static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ 2557 if (sm_ctkd_from_le(connection)){ 2558 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; 2559 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 2560 } else { 2561 sm_master_pairing_success(connection); 2562 } 2563 } 2564 2565 static void sm_run(void){ 2566 2567 // assert that stack has already bootet 2568 if (hci_get_state() != HCI_STATE_WORKING) return; 2569 2570 // assert that we can send at least commands 2571 if (!hci_can_send_command_packet_now()) return; 2572 2573 // pause until IR/ER are ready 2574 if (sm_persistent_keys_random_active) return; 2575 2576 bool done; 2577 2578 // 2579 // non-connection related behaviour 2580 // 2581 2582 done = sm_run_dpkg(); 2583 if (done) return; 2584 2585 done = sm_run_rau(); 2586 if (done) return; 2587 2588 done = sm_run_csrk(); 2589 if (done) return; 2590 2591 done = sm_run_oob(); 2592 if (done) return; 2593 2594 // assert that we can send at least commands - cmd might have been sent by crypto engine 2595 if (!hci_can_send_command_packet_now()) return; 2596 2597 // handle basic actions that don't requires the full context 2598 done = sm_run_basic(); 2599 if (done) return; 2600 2601 // 2602 // active connection handling 2603 // -- use loop to handle next connection if lock on setup context is released 2604 2605 while (true) { 2606 2607 sm_run_activate_connection(); 2608 2609 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2610 2611 // 2612 // active connection handling 2613 // 2614 2615 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2616 if (!connection) { 2617 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2618 return; 2619 } 2620 2621 // assert that we could send a SM PDU - not needed for all of the following 2622 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { 2623 log_info("cannot send now, requesting can send now event"); 2624 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); 2625 return; 2626 } 2627 2628 // send keypress notifications 2629 if (setup->sm_keypress_notification){ 2630 sm_run_send_keypress_notification(connection); 2631 return; 2632 } 2633 2634 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2635 // assert that sm cmac engine is ready 2636 if (sm_cmac_ready() == false){ 2637 break; 2638 } 2639 #endif 2640 2641 int key_distribution_flags; 2642 UNUSED(key_distribution_flags); 2643 #ifdef ENABLE_LE_PERIPHERAL 2644 int err; 2645 bool have_ltk; 2646 uint8_t ltk[16]; 2647 #endif 2648 2649 log_info("sm_run: state %u", connection->sm_engine_state); 2650 switch (connection->sm_engine_state){ 2651 2652 // secure connections, initiator + responding states 2653 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2654 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2655 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2656 sm_sc_calculate_local_confirm(connection); 2657 break; 2658 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2659 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2660 sm_sc_calculate_remote_confirm(connection); 2661 break; 2662 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2663 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2664 sm_sc_calculate_f6_for_dhkey_check(connection); 2665 break; 2666 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2667 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2668 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2669 break; 2670 case SM_SC_W2_CALCULATE_F5_SALT: 2671 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2672 f5_calculate_salt(connection); 2673 break; 2674 case SM_SC_W2_CALCULATE_F5_MACKEY: 2675 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2676 f5_calculate_mackey(connection); 2677 break; 2678 case SM_SC_W2_CALCULATE_F5_LTK: 2679 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2680 f5_calculate_ltk(connection); 2681 break; 2682 case SM_SC_W2_CALCULATE_G2: 2683 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2684 g2_calculate(connection); 2685 break; 2686 #endif 2687 2688 #ifdef ENABLE_LE_CENTRAL 2689 // initiator side 2690 2691 case SM_INITIATOR_PH4_HAS_LTK: { 2692 sm_reset_setup(); 2693 sm_load_security_info(connection); 2694 2695 sm_key_t peer_ltk_flipped; 2696 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2697 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2698 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2699 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2700 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2701 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2702 2703 // notify after sending 2704 sm_reencryption_started(connection); 2705 return; 2706 } 2707 2708 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2709 sm_reset_setup(); 2710 sm_init_setup(connection); 2711 2712 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2713 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2714 sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2715 sm_timeout_reset(connection); 2716 2717 // notify after sending 2718 sm_pairing_started(connection); 2719 break; 2720 #endif 2721 2722 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2723 2724 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2725 bool trigger_user_response = false; 2726 bool trigger_start_calculating_local_confirm = false; 2727 uint8_t buffer[65]; 2728 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2729 // 2730 reverse_256(&ec_q[0], &buffer[1]); 2731 reverse_256(&ec_q[32], &buffer[33]); 2732 2733 #ifdef ENABLE_TESTING_SUPPORT 2734 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2735 log_info("testing_support: invalidating public key"); 2736 // flip single bit of public key coordinate 2737 buffer[1] ^= 1; 2738 } 2739 #endif 2740 2741 // stk generation method 2742 // passkey entry: notify app to show passkey or to request passkey 2743 switch (setup->sm_stk_generation_method){ 2744 case JUST_WORKS: 2745 case NUMERIC_COMPARISON: 2746 if (IS_RESPONDER(connection->sm_role)){ 2747 // responder 2748 trigger_start_calculating_local_confirm = true; 2749 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2750 } else { 2751 // initiator 2752 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2753 } 2754 break; 2755 case PK_INIT_INPUT: 2756 case PK_RESP_INPUT: 2757 case PK_BOTH_INPUT: 2758 // use random TK for display 2759 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2760 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2761 setup->sm_passkey_bit = 0; 2762 2763 if (IS_RESPONDER(connection->sm_role)){ 2764 // responder 2765 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2766 } else { 2767 // initiator 2768 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2769 } 2770 trigger_user_response = true; 2771 break; 2772 case OOB: 2773 if (IS_RESPONDER(connection->sm_role)){ 2774 // responder 2775 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2776 } else { 2777 // initiator 2778 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2779 } 2780 break; 2781 default: 2782 btstack_assert(false); 2783 break; 2784 } 2785 2786 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2787 sm_timeout_reset(connection); 2788 2789 // trigger user response and calc confirm after sending pdu 2790 if (trigger_user_response){ 2791 sm_trigger_user_response(connection); 2792 } 2793 if (trigger_start_calculating_local_confirm){ 2794 sm_sc_start_calculating_local_confirm(connection); 2795 } 2796 break; 2797 } 2798 case SM_SC_SEND_CONFIRMATION: { 2799 uint8_t buffer[17]; 2800 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2801 reverse_128(setup->sm_local_confirm, &buffer[1]); 2802 if (IS_RESPONDER(connection->sm_role)){ 2803 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2804 } else { 2805 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2806 } 2807 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2808 sm_timeout_reset(connection); 2809 break; 2810 } 2811 case SM_SC_SEND_PAIRING_RANDOM: { 2812 uint8_t buffer[17]; 2813 buffer[0] = SM_CODE_PAIRING_RANDOM; 2814 reverse_128(setup->sm_local_nonce, &buffer[1]); 2815 log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2816 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2817 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2818 if (IS_RESPONDER(connection->sm_role)){ 2819 // responder 2820 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2821 } else { 2822 // initiator 2823 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2824 } 2825 } else { 2826 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2827 if (IS_RESPONDER(connection->sm_role)){ 2828 // responder 2829 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2830 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2831 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2832 } else { 2833 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2834 sm_sc_prepare_dhkey_check(connection); 2835 } 2836 } else { 2837 // initiator 2838 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2839 } 2840 } 2841 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2842 sm_timeout_reset(connection); 2843 break; 2844 } 2845 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2846 uint8_t buffer[17]; 2847 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2848 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2849 2850 if (IS_RESPONDER(connection->sm_role)){ 2851 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2852 } else { 2853 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2854 } 2855 2856 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2857 sm_timeout_reset(connection); 2858 break; 2859 } 2860 2861 #endif 2862 2863 #ifdef ENABLE_LE_PERIPHERAL 2864 2865 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2866 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2867 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2868 sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); 2869 sm_timeout_start(connection); 2870 break; 2871 } 2872 2873 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2874 case SM_SC_RECEIVED_LTK_REQUEST: 2875 switch (connection->sm_irk_lookup_state){ 2876 case IRK_LOOKUP_SUCCEEDED: 2877 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2878 // start using context by loading security info 2879 sm_reset_setup(); 2880 sm_load_security_info(connection); 2881 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2882 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2883 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2884 sm_reencryption_started(connection); 2885 sm_trigger_run(); 2886 break; 2887 } 2888 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2889 connection->sm_engine_state = SM_RESPONDER_IDLE; 2890 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2891 return; 2892 default: 2893 // just wait until IRK lookup is completed 2894 break; 2895 } 2896 break; 2897 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2898 2899 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2900 sm_reset_setup(); 2901 2902 // handle Pairing Request with LTK available 2903 switch (connection->sm_irk_lookup_state) { 2904 case IRK_LOOKUP_SUCCEEDED: 2905 le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 2906 have_ltk = !sm_is_null_key(ltk); 2907 if (have_ltk){ 2908 log_info("pairing request but LTK available"); 2909 // emit re-encryption start/fail sequence 2910 sm_reencryption_started(connection); 2911 sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); 2912 } 2913 break; 2914 default: 2915 break; 2916 } 2917 2918 sm_init_setup(connection); 2919 2920 // recover pairing request 2921 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2922 err = sm_stk_generation_init(connection); 2923 2924 #ifdef ENABLE_TESTING_SUPPORT 2925 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2926 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2927 err = test_pairing_failure; 2928 } 2929 #endif 2930 if (err != 0){ 2931 // emit pairing started/failed sequence 2932 sm_pairing_started(connection); 2933 sm_pairing_error(connection, err); 2934 sm_trigger_run(); 2935 break; 2936 } 2937 2938 sm_timeout_start(connection); 2939 2940 // generate random number first, if we need to show passkey, otherwise send response 2941 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2942 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2943 break; 2944 } 2945 2946 /* fall through */ 2947 2948 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2949 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2950 2951 // start with initiator key dist flags 2952 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2953 2954 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2955 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2956 if (setup->sm_use_secure_connections){ 2957 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2958 } 2959 #endif 2960 // setup in response 2961 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); 2962 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); 2963 2964 // update key distribution after ENC was dropped 2965 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)); 2966 2967 if (setup->sm_use_secure_connections){ 2968 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2969 } else { 2970 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2971 } 2972 2973 sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2974 sm_timeout_reset(connection); 2975 2976 // notify after sending 2977 sm_pairing_started(connection); 2978 2979 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2980 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2981 sm_trigger_user_response(connection); 2982 } 2983 return; 2984 #endif 2985 2986 case SM_PH2_SEND_PAIRING_RANDOM: { 2987 uint8_t buffer[17]; 2988 buffer[0] = SM_CODE_PAIRING_RANDOM; 2989 reverse_128(setup->sm_local_random, &buffer[1]); 2990 if (IS_RESPONDER(connection->sm_role)){ 2991 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2992 } else { 2993 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2994 } 2995 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 2996 sm_timeout_reset(connection); 2997 break; 2998 } 2999 3000 case SM_PH2_C1_GET_ENC_A: 3001 // already busy? 3002 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3003 // calculate confirm using aes128 engine - step 1 3004 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); 3005 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 3006 sm_aes128_state = SM_AES128_ACTIVE; 3007 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); 3008 break; 3009 3010 case SM_PH2_C1_GET_ENC_C: 3011 // already busy? 3012 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3013 // calculate m_confirm using aes128 engine - step 1 3014 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); 3015 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 3016 sm_aes128_state = SM_AES128_ACTIVE; 3017 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); 3018 break; 3019 3020 case SM_PH2_CALC_STK: 3021 // already busy? 3022 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3023 // calculate STK 3024 if (IS_RESPONDER(connection->sm_role)){ 3025 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 3026 } else { 3027 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3028 } 3029 connection->sm_engine_state = SM_PH2_W4_STK; 3030 sm_aes128_state = SM_AES128_ACTIVE; 3031 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); 3032 break; 3033 3034 case SM_PH3_Y_GET_ENC: 3035 // already busy? 3036 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3037 // PH3B2 - calculate Y from - enc 3038 3039 // dm helper (was sm_dm_r_prime) 3040 // r' = padding || r 3041 // r - 64 bit value 3042 memset(&sm_aes128_plaintext[0], 0, 8); 3043 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3044 3045 // Y = dm(DHK, Rand) 3046 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 3047 sm_aes128_state = SM_AES128_ACTIVE; 3048 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); 3049 break; 3050 3051 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 3052 uint8_t buffer[17]; 3053 buffer[0] = SM_CODE_PAIRING_CONFIRM; 3054 reverse_128(setup->sm_local_confirm, &buffer[1]); 3055 if (IS_RESPONDER(connection->sm_role)){ 3056 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 3057 } else { 3058 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 3059 } 3060 sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); 3061 sm_timeout_reset(connection); 3062 return; 3063 } 3064 #ifdef ENABLE_LE_PERIPHERAL 3065 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 3066 sm_key_t stk_flipped; 3067 reverse_128(setup->sm_ltk, stk_flipped); 3068 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3069 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 3070 return; 3071 } 3072 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 3073 // allow to override LTK 3074 if (sm_get_ltk_callback != NULL){ 3075 (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); 3076 } 3077 sm_key_t ltk_flipped; 3078 reverse_128(setup->sm_ltk, ltk_flipped); 3079 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 3080 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 3081 return; 3082 } 3083 3084 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 3085 // already busy? 3086 if (sm_aes128_state == SM_AES128_ACTIVE) break; 3087 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 3088 3089 sm_reset_setup(); 3090 sm_start_calculating_ltk_from_ediv_and_rand(connection); 3091 3092 sm_reencryption_started(connection); 3093 3094 // dm helper (was sm_dm_r_prime) 3095 // r' = padding || r 3096 // r - 64 bit value 3097 memset(&sm_aes128_plaintext[0], 0, 8); 3098 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 3099 3100 // Y = dm(DHK, Rand) 3101 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 3102 sm_aes128_state = SM_AES128_ACTIVE; 3103 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); 3104 return; 3105 #endif 3106 #ifdef ENABLE_LE_CENTRAL 3107 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 3108 sm_key_t stk_flipped; 3109 reverse_128(setup->sm_ltk, stk_flipped); 3110 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 3111 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 3112 return; 3113 } 3114 #endif 3115 3116 case SM_PH3_DISTRIBUTE_KEYS: 3117 // send next key 3118 if (setup->sm_key_distribution_send_set != 0){ 3119 sm_run_distribute_keys(connection); 3120 } 3121 3122 // more to send? 3123 if (setup->sm_key_distribution_send_set != 0){ 3124 return; 3125 } 3126 3127 // keys are sent 3128 if (IS_RESPONDER(connection->sm_role)){ 3129 // slave -> receive master keys if any 3130 if (sm_key_distribution_all_received()){ 3131 sm_key_distribution_handle_all_received(connection); 3132 sm_key_distribution_complete_responder(connection); 3133 // start CTKD right away 3134 continue; 3135 } else { 3136 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3137 } 3138 } else { 3139 sm_master_pairing_success(connection); 3140 } 3141 break; 3142 3143 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3144 case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: 3145 // fill in sm setup (lite version of sm_init_setup) 3146 sm_reset_setup(); 3147 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3148 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3149 setup->sm_s_addr_type = connection->sm_own_addr_type; 3150 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3151 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3152 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3153 setup->sm_use_secure_connections = true; 3154 sm_ctkd_fetch_br_edr_link_key(connection); 3155 3156 // Enc Key and IRK if requested 3157 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3158 #ifdef ENABLE_LE_SIGNED_WRITE 3159 // Plus signing key if supported 3160 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3161 #endif 3162 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 3163 sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); 3164 sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); 3165 sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); 3166 sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); 3167 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 3168 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 3169 3170 // set state and send pairing response 3171 sm_timeout_start(connection); 3172 connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; 3173 sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 3174 break; 3175 3176 case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: 3177 // fill in sm setup (lite version of sm_init_setup) 3178 sm_reset_setup(); 3179 setup->sm_peer_addr_type = connection->sm_peer_addr_type; 3180 setup->sm_m_addr_type = connection->sm_peer_addr_type; 3181 setup->sm_s_addr_type = connection->sm_own_addr_type; 3182 (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); 3183 (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); 3184 (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); 3185 setup->sm_use_secure_connections = true; 3186 sm_ctkd_fetch_br_edr_link_key(connection); 3187 (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 3188 3189 // Enc Key and IRK if requested 3190 key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; 3191 #ifdef ENABLE_LE_SIGNED_WRITE 3192 // Plus signing key if supported 3193 key_distribution_flags |= SM_KEYDIST_ID_KEY; 3194 #endif 3195 // drop flags not requested by initiator 3196 key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); 3197 3198 // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: 3199 // - the IO Capability field, 3200 // - the OOB data flag field, and 3201 // - all bits in the Auth Req field except the CT2 bit. 3202 sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); 3203 sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); 3204 sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); 3205 sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); 3206 sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); 3207 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); 3208 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); 3209 3210 // configure key distribution, LTK is derived locally 3211 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 3212 sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); 3213 3214 // set state and send pairing response 3215 sm_timeout_start(connection); 3216 connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 3217 sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 3218 break; 3219 case SM_BR_EDR_DISTRIBUTE_KEYS: 3220 if (setup->sm_key_distribution_send_set != 0) { 3221 sm_run_distribute_keys(connection); 3222 return; 3223 } 3224 // keys are sent 3225 if (IS_RESPONDER(connection->sm_role)) { 3226 // responder -> receive master keys if there are any 3227 if (!sm_key_distribution_all_received()){ 3228 connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 3229 break; 3230 } 3231 } 3232 // otherwise start CTKD right away (responder and no keys to receive / initiator) 3233 sm_ctkd_start_from_br_edr(connection); 3234 continue; 3235 case SM_SC_W2_CALCULATE_ILK_USING_H6: 3236 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3237 h6_calculate_ilk_from_le_ltk(connection); 3238 break; 3239 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 3240 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 3241 h6_calculate_br_edr_link_key(connection); 3242 break; 3243 case SM_SC_W2_CALCULATE_ILK_USING_H7: 3244 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 3245 h7_calculate_ilk_from_le_ltk(connection); 3246 break; 3247 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: 3248 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3249 h6_calculate_ilk_from_br_edr(connection); 3250 break; 3251 case SM_BR_EDR_W2_CALCULATE_LE_LTK: 3252 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; 3253 h6_calculate_le_ltk(connection); 3254 break; 3255 case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: 3256 connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; 3257 h7_calculate_ilk_from_br_edr(connection); 3258 break; 3259 #endif 3260 3261 default: 3262 break; 3263 } 3264 3265 // check again if active connection was released 3266 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 3267 } 3268 } 3269 3270 // sm_aes128_state stays active 3271 static void sm_handle_encryption_result_enc_a(void *arg){ 3272 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3273 sm_aes128_state = SM_AES128_IDLE; 3274 3275 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3276 if (connection == NULL) return; 3277 3278 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3279 sm_aes128_state = SM_AES128_ACTIVE; 3280 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); 3281 } 3282 3283 static void sm_handle_encryption_result_enc_b(void *arg){ 3284 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3285 sm_aes128_state = SM_AES128_IDLE; 3286 3287 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3288 if (connection == NULL) return; 3289 3290 log_info_key("c1!", setup->sm_local_confirm); 3291 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 3292 sm_trigger_run(); 3293 } 3294 3295 // sm_aes128_state stays active 3296 static void sm_handle_encryption_result_enc_c(void *arg){ 3297 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3298 sm_aes128_state = SM_AES128_IDLE; 3299 3300 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3301 if (connection == NULL) return; 3302 3303 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 3304 sm_aes128_state = SM_AES128_ACTIVE; 3305 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); 3306 } 3307 3308 static void sm_handle_encryption_result_enc_d(void * arg){ 3309 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3310 sm_aes128_state = SM_AES128_IDLE; 3311 3312 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3313 if (connection == NULL) return; 3314 3315 log_info_key("c1!", sm_aes128_ciphertext); 3316 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 3317 sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); 3318 sm_trigger_run(); 3319 return; 3320 } 3321 if (IS_RESPONDER(connection->sm_role)){ 3322 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3323 sm_trigger_run(); 3324 } else { 3325 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 3326 sm_aes128_state = SM_AES128_ACTIVE; 3327 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); 3328 } 3329 } 3330 3331 static void sm_handle_encryption_result_enc_stk(void *arg){ 3332 sm_aes128_state = SM_AES128_IDLE; 3333 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3334 3335 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3336 if (connection == NULL) return; 3337 3338 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3339 log_info_key("stk", setup->sm_ltk); 3340 if (IS_RESPONDER(connection->sm_role)){ 3341 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3342 } else { 3343 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 3344 } 3345 sm_trigger_run(); 3346 } 3347 3348 // sm_aes128_state stays active 3349 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 3350 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3351 sm_aes128_state = SM_AES128_IDLE; 3352 3353 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3354 if (connection == NULL) return; 3355 3356 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3357 log_info_hex16("y", setup->sm_local_y); 3358 // PH3B3 - calculate EDIV 3359 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3360 log_info_hex16("ediv", setup->sm_local_ediv); 3361 // PH3B4 - calculate LTK - enc 3362 // LTK = d1(ER, DIV, 0)) 3363 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3364 sm_aes128_state = SM_AES128_ACTIVE; 3365 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); 3366 } 3367 3368 #ifdef ENABLE_LE_PERIPHERAL 3369 // sm_aes128_state stays active 3370 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3371 sm_aes128_state = SM_AES128_IDLE; 3372 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3373 3374 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3375 if (connection == NULL) return; 3376 3377 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3378 log_info_hex16("y", setup->sm_local_y); 3379 3380 // PH3B3 - calculate DIV 3381 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3382 log_info_hex16("ediv", setup->sm_local_ediv); 3383 // PH3B4 - calculate LTK - enc 3384 // LTK = d1(ER, DIV, 0)) 3385 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3386 sm_aes128_state = SM_AES128_ACTIVE; 3387 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); 3388 } 3389 #endif 3390 3391 // sm_aes128_state stays active 3392 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3393 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3394 sm_aes128_state = SM_AES128_IDLE; 3395 3396 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3397 if (connection == NULL) return; 3398 3399 log_info_key("ltk", setup->sm_ltk); 3400 // calc CSRK next 3401 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3402 sm_aes128_state = SM_AES128_ACTIVE; 3403 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); 3404 } 3405 3406 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3407 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3408 sm_aes128_state = SM_AES128_IDLE; 3409 3410 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3411 if (connection == NULL) return; 3412 3413 sm_aes128_state = SM_AES128_IDLE; 3414 log_info_key("csrk", setup->sm_local_csrk); 3415 if (setup->sm_key_distribution_send_set){ 3416 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3417 } else { 3418 // no keys to send, just continue 3419 if (IS_RESPONDER(connection->sm_role)){ 3420 if (sm_key_distribution_all_received()){ 3421 sm_key_distribution_handle_all_received(connection); 3422 sm_key_distribution_complete_responder(connection); 3423 } else { 3424 // slave -> receive master keys 3425 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3426 } 3427 } else { 3428 sm_key_distribution_complete_initiator(connection); 3429 } 3430 } 3431 sm_trigger_run(); 3432 } 3433 3434 #ifdef ENABLE_LE_PERIPHERAL 3435 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3436 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3437 sm_aes128_state = SM_AES128_IDLE; 3438 3439 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3440 if (connection == NULL) return; 3441 3442 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3443 log_info_key("ltk", setup->sm_ltk); 3444 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3445 sm_trigger_run(); 3446 } 3447 #endif 3448 3449 static void sm_handle_encryption_result_address_resolution(void *arg){ 3450 UNUSED(arg); 3451 sm_aes128_state = SM_AES128_IDLE; 3452 3453 sm_address_resolution_ah_calculation_active = 0; 3454 // compare calulated address against connecting device 3455 uint8_t * hash = &sm_aes128_ciphertext[13]; 3456 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3457 log_info("LE Device Lookup: matched resolvable private address"); 3458 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3459 sm_trigger_run(); 3460 return; 3461 } 3462 // no match, try next 3463 sm_address_resolution_test++; 3464 sm_trigger_run(); 3465 } 3466 3467 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3468 UNUSED(arg); 3469 sm_aes128_state = SM_AES128_IDLE; 3470 3471 log_info_key("irk", sm_persistent_irk); 3472 dkg_state = DKG_CALC_DHK; 3473 sm_trigger_run(); 3474 } 3475 3476 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3477 UNUSED(arg); 3478 sm_aes128_state = SM_AES128_IDLE; 3479 3480 log_info_key("dhk", sm_persistent_dhk); 3481 dkg_state = DKG_READY; 3482 sm_trigger_run(); 3483 } 3484 3485 static void sm_handle_encryption_result_rau(void *arg){ 3486 UNUSED(arg); 3487 sm_aes128_state = SM_AES128_IDLE; 3488 3489 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3490 rau_state = RAU_IDLE; 3491 hci_le_random_address_set(sm_random_address); 3492 3493 sm_trigger_run(); 3494 } 3495 3496 static void sm_handle_random_result_rau(void * arg){ 3497 UNUSED(arg); 3498 // non-resolvable vs. resolvable 3499 switch (gap_random_adress_type){ 3500 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3501 // resolvable: use random as prand and calc address hash 3502 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3503 sm_random_address[0u] &= 0x3fu; 3504 sm_random_address[0u] |= 0x40u; 3505 rau_state = RAU_GET_ENC; 3506 break; 3507 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3508 default: 3509 // "The two most significant bits of the address shall be equal to ‘0’"" 3510 sm_random_address[0u] &= 0x3fu; 3511 rau_state = RAU_IDLE; 3512 hci_le_random_address_set(sm_random_address); 3513 break; 3514 } 3515 sm_trigger_run(); 3516 } 3517 3518 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3519 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3520 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3521 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3522 if (connection == NULL) return; 3523 3524 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3525 sm_trigger_run(); 3526 } 3527 3528 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3529 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3530 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3531 if (connection == NULL) return; 3532 3533 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3534 sm_trigger_run(); 3535 } 3536 #endif 3537 3538 static void sm_handle_random_result_ph2_random(void * arg){ 3539 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3540 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3541 if (connection == NULL) return; 3542 3543 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3544 sm_trigger_run(); 3545 } 3546 3547 static void sm_handle_random_result_ph2_tk(void * arg){ 3548 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3549 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3550 if (connection == NULL) return; 3551 3552 sm_reset_tk(); 3553 uint32_t tk; 3554 if (sm_fixed_passkey_in_display_role == 0xffffffffU){ 3555 // map random to 0-999999 without speding much cycles on a modulus operation 3556 tk = little_endian_read_32(sm_random_data,0); 3557 tk = tk & 0xfffff; // 1048575 3558 if (tk >= 999999u){ 3559 tk = tk - 999999u; 3560 } 3561 } else { 3562 // override with pre-defined passkey 3563 tk = sm_fixed_passkey_in_display_role; 3564 } 3565 big_endian_store_32(setup->sm_tk, 12, tk); 3566 if (IS_RESPONDER(connection->sm_role)){ 3567 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3568 } else { 3569 if (setup->sm_use_secure_connections){ 3570 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3571 } else { 3572 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3573 sm_trigger_user_response(connection); 3574 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3575 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3576 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); 3577 } 3578 } 3579 } 3580 sm_trigger_run(); 3581 } 3582 3583 static void sm_handle_random_result_ph3_div(void * arg){ 3584 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3585 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3586 if (connection == NULL) return; 3587 3588 // use 16 bit from random value as div 3589 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3590 log_info_hex16("div", setup->sm_local_div); 3591 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3592 sm_trigger_run(); 3593 } 3594 3595 static void sm_handle_random_result_ph3_random(void * arg){ 3596 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3597 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3598 if (connection == NULL) return; 3599 3600 reverse_64(sm_random_data, setup->sm_local_rand); 3601 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3602 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3603 // no db for authenticated flag hack: store flag in bit 4 of LSB 3604 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3605 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3606 } 3607 static void sm_validate_er_ir(void){ 3608 // warn about default ER/IR 3609 bool warning = false; 3610 if (sm_ir_is_default()){ 3611 warning = true; 3612 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3613 } 3614 if (sm_er_is_default()){ 3615 warning = true; 3616 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3617 } 3618 if (warning) { 3619 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3620 } 3621 } 3622 3623 static void sm_handle_random_result_ir(void *arg){ 3624 sm_persistent_keys_random_active = false; 3625 if (arg != NULL){ 3626 // key generated, store in tlv 3627 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3628 log_info("Generated IR key. Store in TLV status: %d", status); 3629 UNUSED(status); 3630 } 3631 log_info_key("IR", sm_persistent_ir); 3632 dkg_state = DKG_CALC_IRK; 3633 3634 if (test_use_fixed_local_irk){ 3635 log_info_key("IRK", sm_persistent_irk); 3636 dkg_state = DKG_CALC_DHK; 3637 } 3638 3639 sm_trigger_run(); 3640 } 3641 3642 static void sm_handle_random_result_er(void *arg){ 3643 sm_persistent_keys_random_active = false; 3644 if (arg != 0){ 3645 // key generated, store in tlv 3646 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3647 log_info("Generated ER key. Store in TLV status: %d", status); 3648 UNUSED(status); 3649 } 3650 log_info_key("ER", sm_persistent_er); 3651 3652 // try load ir 3653 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3654 if (key_size == 16){ 3655 // ok, let's continue 3656 log_info("IR from TLV"); 3657 sm_handle_random_result_ir( NULL ); 3658 } else { 3659 // invalid, generate new random one 3660 sm_persistent_keys_random_active = true; 3661 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3662 } 3663 } 3664 3665 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){ 3666 3667 // connection info 3668 sm_conn->sm_handle = con_handle; 3669 sm_conn->sm_role = role; 3670 sm_conn->sm_peer_addr_type = addr_type; 3671 memcpy(sm_conn->sm_peer_address, address, 6); 3672 3673 // security properties 3674 sm_conn->sm_connection_encrypted = 0; 3675 sm_conn->sm_connection_authenticated = 0; 3676 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3677 sm_conn->sm_le_db_index = -1; 3678 sm_conn->sm_reencryption_active = false; 3679 3680 // prepare CSRK lookup (does not involve setup) 3681 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3682 3683 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3684 } 3685 3686 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3687 3688 UNUSED(channel); // ok: there is no channel 3689 UNUSED(size); // ok: fixed format HCI events 3690 3691 sm_connection_t * sm_conn; 3692 hci_con_handle_t con_handle; 3693 uint8_t status; 3694 bd_addr_t addr; 3695 3696 switch (packet_type) { 3697 3698 case HCI_EVENT_PACKET: 3699 switch (hci_event_packet_get_type(packet)) { 3700 3701 case BTSTACK_EVENT_STATE: 3702 switch (btstack_event_state_get_state(packet)){ 3703 case HCI_STATE_WORKING: 3704 log_info("HCI Working!"); 3705 // setup IR/ER with TLV 3706 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3707 if (sm_tlv_impl != NULL){ 3708 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3709 if (key_size == 16){ 3710 // ok, let's continue 3711 log_info("ER from TLV"); 3712 sm_handle_random_result_er( NULL ); 3713 } else { 3714 // invalid, generate random one 3715 sm_persistent_keys_random_active = true; 3716 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3717 } 3718 } else { 3719 sm_validate_er_ir(); 3720 dkg_state = DKG_CALC_IRK; 3721 3722 if (test_use_fixed_local_irk){ 3723 log_info_key("IRK", sm_persistent_irk); 3724 dkg_state = DKG_CALC_DHK; 3725 } 3726 } 3727 3728 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3729 // trigger ECC key generation 3730 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 3731 sm_ec_generate_new_key(); 3732 } 3733 #endif 3734 3735 // restart random address updates after power cycle 3736 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ 3737 gap_random_address_set(sm_random_address); 3738 } else { 3739 gap_random_address_set_mode(gap_random_adress_type); 3740 } 3741 break; 3742 3743 case HCI_STATE_OFF: 3744 case HCI_STATE_HALTING: 3745 log_info("SM: reset state"); 3746 // stop random address update 3747 gap_random_address_update_stop(); 3748 // reset state 3749 sm_state_reset(); 3750 break; 3751 3752 default: 3753 break; 3754 } 3755 break; 3756 3757 #ifdef ENABLE_CLASSIC 3758 case HCI_EVENT_CONNECTION_COMPLETE: 3759 // ignore if connection failed 3760 if (hci_event_connection_complete_get_status(packet)) return; 3761 3762 con_handle = hci_event_connection_complete_get_connection_handle(packet); 3763 sm_conn = sm_get_connection_for_handle(con_handle); 3764 if (!sm_conn) break; 3765 3766 hci_event_connection_complete_get_bd_addr(packet, addr); 3767 sm_connection_init(sm_conn, 3768 con_handle, 3769 (uint8_t) gap_get_role(con_handle), 3770 BD_ADDR_TYPE_LE_PUBLIC, 3771 addr); 3772 // classic connection corresponds to public le address 3773 sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; 3774 gap_local_bd_addr(sm_conn->sm_own_address); 3775 sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; 3776 sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; 3777 break; 3778 #endif 3779 3780 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3781 case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: 3782 if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; 3783 hci_event_simple_pairing_complete_get_bd_addr(packet, addr); 3784 sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); 3785 if (sm_conn == NULL) break; 3786 sm_conn->sm_pairing_requested = 1; 3787 break; 3788 #endif 3789 3790 case HCI_EVENT_LE_META: 3791 switch (packet[2]) { 3792 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3793 // ignore if connection failed 3794 if (packet[3]) return; 3795 3796 con_handle = little_endian_read_16(packet, 4); 3797 sm_conn = sm_get_connection_for_handle(con_handle); 3798 if (!sm_conn) break; 3799 3800 hci_subevent_le_connection_complete_get_peer_address(packet, addr); 3801 sm_connection_init(sm_conn, 3802 con_handle, 3803 hci_subevent_le_connection_complete_get_role(packet), 3804 hci_subevent_le_connection_complete_get_peer_address_type(packet), 3805 addr); 3806 sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 3807 3808 // track our addr used for this connection and set state 3809 #ifdef ENABLE_LE_PERIPHERAL 3810 if (hci_subevent_le_connection_complete_get_role(packet) != 0){ 3811 // responder - use own address from advertisements 3812 gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3813 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3814 } 3815 #endif 3816 #ifdef ENABLE_LE_CENTRAL 3817 if (hci_subevent_le_connection_complete_get_role(packet) == 0){ 3818 // initiator - use own address from create connection 3819 gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); 3820 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3821 } 3822 #endif 3823 break; 3824 3825 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3826 con_handle = little_endian_read_16(packet, 3); 3827 sm_conn = sm_get_connection_for_handle(con_handle); 3828 if (!sm_conn) break; 3829 3830 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3831 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3832 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3833 break; 3834 } 3835 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3836 // PH2 SEND LTK as we need to exchange keys in PH3 3837 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3838 break; 3839 } 3840 3841 // store rand and ediv 3842 reverse_64(&packet[5], sm_conn->sm_local_rand); 3843 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3844 3845 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3846 // potentially stored LTK is from the master 3847 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3848 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3849 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3850 break; 3851 } 3852 // additionally check if remote is in LE Device DB if requested 3853 switch(sm_conn->sm_irk_lookup_state){ 3854 case IRK_LOOKUP_FAILED: 3855 log_info("LTK Request: device not in device db"); 3856 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3857 break; 3858 case IRK_LOOKUP_SUCCEEDED: 3859 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3860 break; 3861 default: 3862 // wait for irk look doen 3863 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3864 break; 3865 } 3866 break; 3867 } 3868 3869 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3870 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3871 #else 3872 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3873 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3874 #endif 3875 break; 3876 3877 default: 3878 break; 3879 } 3880 break; 3881 3882 case HCI_EVENT_ENCRYPTION_CHANGE: 3883 case HCI_EVENT_ENCRYPTION_CHANGE_V2: 3884 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3885 sm_conn = sm_get_connection_for_handle(con_handle); 3886 if (!sm_conn) break; 3887 3888 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3889 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3890 sm_conn->sm_actual_encryption_key_size); 3891 log_info("event handler, state %u", sm_conn->sm_engine_state); 3892 3893 switch (sm_conn->sm_engine_state){ 3894 3895 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3896 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3897 if (sm_conn->sm_connection_encrypted) { 3898 status = ERROR_CODE_SUCCESS; 3899 if (sm_conn->sm_role){ 3900 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3901 } else { 3902 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3903 } 3904 } else { 3905 status = hci_event_encryption_change_get_status(packet); 3906 // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions 3907 // also, gap_reconnect_security_setup_active will return true 3908 sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; 3909 } 3910 3911 // emit re-encryption complete 3912 sm_reencryption_complete(sm_conn, status); 3913 3914 // notify client, if pairing was requested before 3915 if (sm_conn->sm_pairing_requested){ 3916 sm_conn->sm_pairing_requested = 0; 3917 sm_pairing_complete(sm_conn, status, 0); 3918 } 3919 3920 sm_done_for_handle(sm_conn->sm_handle); 3921 break; 3922 3923 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3924 if (!sm_conn->sm_connection_encrypted) break; 3925 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3926 if (IS_RESPONDER(sm_conn->sm_role)){ 3927 // slave 3928 if (setup->sm_use_secure_connections){ 3929 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3930 } else { 3931 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); 3932 } 3933 } else { 3934 // master 3935 if (sm_key_distribution_all_received()){ 3936 // skip receiving keys as there are none 3937 sm_key_distribution_handle_all_received(sm_conn); 3938 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); 3939 } else { 3940 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3941 } 3942 } 3943 break; 3944 3945 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3946 case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: 3947 if (sm_conn->sm_connection_encrypted != 2) break; 3948 // prepare for pairing request 3949 if (IS_RESPONDER(sm_conn->sm_role)){ 3950 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; 3951 } else if (sm_conn->sm_pairing_requested){ 3952 // only send LE pairing request after BR/EDR SSP 3953 sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; 3954 } 3955 break; 3956 #endif 3957 default: 3958 break; 3959 } 3960 break; 3961 3962 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3963 con_handle = little_endian_read_16(packet, 3); 3964 sm_conn = sm_get_connection_for_handle(con_handle); 3965 if (!sm_conn) break; 3966 3967 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3968 log_info("event handler, state %u", sm_conn->sm_engine_state); 3969 // continue if part of initial pairing 3970 switch (sm_conn->sm_engine_state){ 3971 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3972 if (sm_conn->sm_role){ 3973 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3974 } else { 3975 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3976 } 3977 sm_done_for_handle(sm_conn->sm_handle); 3978 break; 3979 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3980 if (IS_RESPONDER(sm_conn->sm_role)){ 3981 // slave 3982 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); 3983 } else { 3984 // master 3985 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3986 } 3987 break; 3988 default: 3989 break; 3990 } 3991 break; 3992 3993 3994 case HCI_EVENT_DISCONNECTION_COMPLETE: 3995 con_handle = little_endian_read_16(packet, 3); 3996 sm_done_for_handle(con_handle); 3997 sm_conn = sm_get_connection_for_handle(con_handle); 3998 if (!sm_conn) break; 3999 4000 // pairing failed, if it was ongoing 4001 switch (sm_conn->sm_engine_state){ 4002 case SM_GENERAL_IDLE: 4003 case SM_INITIATOR_CONNECTED: 4004 case SM_RESPONDER_IDLE: 4005 break; 4006 default: 4007 sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); 4008 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 4009 break; 4010 } 4011 4012 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 4013 sm_conn->sm_handle = 0; 4014 break; 4015 4016 case HCI_EVENT_COMMAND_COMPLETE: 4017 if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { 4018 // set local addr for le device db 4019 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 4020 le_device_db_set_local_bd_addr(addr); 4021 } 4022 break; 4023 default: 4024 break; 4025 } 4026 break; 4027 default: 4028 break; 4029 } 4030 4031 sm_run(); 4032 } 4033 4034 static inline int sm_calc_actual_encryption_key_size(int other){ 4035 if (other < sm_min_encryption_key_size) return 0; 4036 if (other < sm_max_encryption_key_size) return other; 4037 return sm_max_encryption_key_size; 4038 } 4039 4040 4041 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4042 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 4043 switch (method){ 4044 case JUST_WORKS: 4045 case NUMERIC_COMPARISON: 4046 return 1; 4047 default: 4048 return 0; 4049 } 4050 } 4051 // responder 4052 4053 static int sm_passkey_used(stk_generation_method_t method){ 4054 switch (method){ 4055 case PK_RESP_INPUT: 4056 return 1; 4057 default: 4058 return 0; 4059 } 4060 } 4061 4062 static int sm_passkey_entry(stk_generation_method_t method){ 4063 switch (method){ 4064 case PK_RESP_INPUT: 4065 case PK_INIT_INPUT: 4066 case PK_BOTH_INPUT: 4067 return 1; 4068 default: 4069 return 0; 4070 } 4071 } 4072 4073 #endif 4074 4075 /** 4076 * @return ok 4077 */ 4078 static int sm_validate_stk_generation_method(void){ 4079 // check if STK generation method is acceptable by client 4080 switch (setup->sm_stk_generation_method){ 4081 case JUST_WORKS: 4082 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 4083 case PK_RESP_INPUT: 4084 case PK_INIT_INPUT: 4085 case PK_BOTH_INPUT: 4086 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 4087 case OOB: 4088 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 4089 case NUMERIC_COMPARISON: 4090 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 4091 default: 4092 return 0; 4093 } 4094 } 4095 4096 #ifdef ENABLE_LE_CENTRAL 4097 static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ 4098 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4099 if (sm_sc_only_mode){ 4100 uint8_t auth_req = packet[1]; 4101 if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ 4102 sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); 4103 return; 4104 } 4105 } 4106 #else 4107 UNUSED(packet); 4108 #endif 4109 4110 int have_ltk; 4111 uint8_t ltk[16]; 4112 4113 // IRK complete? 4114 switch (sm_conn->sm_irk_lookup_state){ 4115 case IRK_LOOKUP_FAILED: 4116 // start pairing 4117 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4118 break; 4119 case IRK_LOOKUP_SUCCEEDED: 4120 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4121 have_ltk = !sm_is_null_key(ltk); 4122 log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); 4123 if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ 4124 // start re-encrypt if we have LTK and the connection is not already encrypted 4125 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4126 } else { 4127 // start pairing 4128 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4129 } 4130 break; 4131 default: 4132 // otherwise, store security request 4133 sm_conn->sm_security_request_received = 1; 4134 break; 4135 } 4136 } 4137 #endif 4138 4139 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 4140 4141 // size of complete sm_pdu used to validate input 4142 static const uint8_t sm_pdu_size[] = { 4143 0, // 0x00 invalid opcode 4144 7, // 0x01 pairing request 4145 7, // 0x02 pairing response 4146 17, // 0x03 pairing confirm 4147 17, // 0x04 pairing random 4148 2, // 0x05 pairing failed 4149 17, // 0x06 encryption information 4150 11, // 0x07 master identification 4151 17, // 0x08 identification information 4152 8, // 0x09 identify address information 4153 17, // 0x0a signing information 4154 2, // 0x0b security request 4155 65, // 0x0c pairing public key 4156 17, // 0x0d pairing dhk check 4157 2, // 0x0e keypress notification 4158 }; 4159 4160 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 4161 sm_run(); 4162 } 4163 4164 if (packet_type != SM_DATA_PACKET) return; 4165 if (size == 0u) return; 4166 4167 uint8_t sm_pdu_code = packet[0]; 4168 4169 // validate pdu size 4170 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 4171 if (sm_pdu_size[sm_pdu_code] != size) return; 4172 4173 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4174 if (!sm_conn) return; 4175 4176 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 4177 sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); 4178 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 4179 sm_done_for_handle(con_handle); 4180 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 4181 return; 4182 } 4183 4184 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 4185 4186 int err; 4187 UNUSED(err); 4188 4189 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 4190 uint8_t buffer[5]; 4191 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 4192 buffer[1] = 3; 4193 little_endian_store_16(buffer, 2, con_handle); 4194 buffer[4] = packet[1]; 4195 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 4196 return; 4197 } 4198 4199 switch (sm_conn->sm_engine_state){ 4200 4201 // a sm timeout requires a new physical connection 4202 case SM_GENERAL_TIMEOUT: 4203 return; 4204 4205 #ifdef ENABLE_LE_CENTRAL 4206 4207 // Initiator 4208 case SM_INITIATOR_CONNECTED: 4209 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 4210 sm_pdu_received_in_wrong_state(sm_conn); 4211 break; 4212 } 4213 sm_initiator_connected_handle_security_request(sm_conn, packet); 4214 break; 4215 4216 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 4217 // Core 5, Vol 3, Part H, 2.4.6: 4218 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 4219 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 4220 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 4221 log_info("Ignoring Security Request"); 4222 break; 4223 } 4224 4225 // all other pdus are incorrect 4226 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4227 sm_pdu_received_in_wrong_state(sm_conn); 4228 break; 4229 } 4230 4231 // store pairing request 4232 (void)memcpy(&setup->sm_s_pres, packet, 4233 sizeof(sm_pairing_packet_t)); 4234 err = sm_stk_generation_init(sm_conn); 4235 4236 #ifdef ENABLE_TESTING_SUPPORT 4237 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 4238 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 4239 err = test_pairing_failure; 4240 } 4241 #endif 4242 4243 if (err != 0){ 4244 sm_pairing_error(sm_conn, err); 4245 break; 4246 } 4247 4248 // generate random number first, if we need to show passkey 4249 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 4250 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); 4251 break; 4252 } 4253 4254 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4255 if (setup->sm_use_secure_connections){ 4256 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 4257 if (setup->sm_stk_generation_method == JUST_WORKS){ 4258 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4259 sm_trigger_user_response(sm_conn); 4260 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4261 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4262 } 4263 } else { 4264 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4265 } 4266 break; 4267 } 4268 #endif 4269 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4270 sm_trigger_user_response(sm_conn); 4271 // response_idle == nothing <--> sm_trigger_user_response() did not require response 4272 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 4273 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); 4274 } 4275 break; 4276 4277 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 4278 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4279 sm_pdu_received_in_wrong_state(sm_conn); 4280 break; 4281 } 4282 4283 // store s_confirm 4284 reverse_128(&packet[1], setup->sm_peer_confirm); 4285 4286 // abort if s_confirm matches m_confirm 4287 if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ 4288 sm_pdu_received_in_wrong_state(sm_conn); 4289 break; 4290 } 4291 4292 #ifdef ENABLE_TESTING_SUPPORT 4293 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4294 log_info("testing_support: reset confirm value"); 4295 memset(setup->sm_peer_confirm, 0, 16); 4296 } 4297 #endif 4298 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 4299 break; 4300 4301 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 4302 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4303 sm_pdu_received_in_wrong_state(sm_conn); 4304 break;; 4305 } 4306 4307 // received random value 4308 reverse_128(&packet[1], setup->sm_peer_random); 4309 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4310 break; 4311 #endif 4312 4313 #ifdef ENABLE_LE_PERIPHERAL 4314 // Responder 4315 case SM_RESPONDER_IDLE: 4316 case SM_RESPONDER_SEND_SECURITY_REQUEST: 4317 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 4318 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4319 sm_pdu_received_in_wrong_state(sm_conn); 4320 break;; 4321 } 4322 4323 // store pairing request 4324 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4325 4326 // check if IRK completed 4327 switch (sm_conn->sm_irk_lookup_state){ 4328 case IRK_LOOKUP_SUCCEEDED: 4329 case IRK_LOOKUP_FAILED: 4330 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 4331 break; 4332 default: 4333 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; 4334 break; 4335 } 4336 break; 4337 #endif 4338 4339 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4340 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4341 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 4342 sm_pdu_received_in_wrong_state(sm_conn); 4343 break; 4344 } 4345 4346 // store public key for DH Key calculation 4347 reverse_256(&packet[01], &setup->sm_peer_q[0]); 4348 reverse_256(&packet[33], &setup->sm_peer_q[32]); 4349 4350 // CVE-2020-26558: abort pairing if remote uses the same public key 4351 if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ 4352 log_info("Remote PK matches ours"); 4353 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4354 break; 4355 } 4356 4357 // validate public key 4358 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 4359 if (err != 0){ 4360 log_info("sm: peer public key invalid %x", err); 4361 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 4362 break; 4363 } 4364 4365 // start calculating dhkey 4366 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); 4367 4368 4369 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 4370 if (IS_RESPONDER(sm_conn->sm_role)){ 4371 // responder 4372 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4373 } else { 4374 // initiator 4375 // stk generation method 4376 // passkey entry: notify app to show passkey or to request passkey 4377 switch (setup->sm_stk_generation_method){ 4378 case JUST_WORKS: 4379 case NUMERIC_COMPARISON: 4380 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 4381 break; 4382 case PK_RESP_INPUT: 4383 sm_sc_start_calculating_local_confirm(sm_conn); 4384 break; 4385 case PK_INIT_INPUT: 4386 case PK_BOTH_INPUT: 4387 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4388 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4389 break; 4390 } 4391 sm_sc_start_calculating_local_confirm(sm_conn); 4392 break; 4393 case OOB: 4394 // generate Nx 4395 log_info("Generate Na"); 4396 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); 4397 break; 4398 default: 4399 btstack_assert(false); 4400 break; 4401 } 4402 } 4403 break; 4404 4405 case SM_SC_W4_CONFIRMATION: 4406 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4407 sm_pdu_received_in_wrong_state(sm_conn); 4408 break; 4409 } 4410 // received confirm value 4411 reverse_128(&packet[1], setup->sm_peer_confirm); 4412 4413 #ifdef ENABLE_TESTING_SUPPORT 4414 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4415 log_info("testing_support: reset confirm value"); 4416 memset(setup->sm_peer_confirm, 0, 16); 4417 } 4418 #endif 4419 if (IS_RESPONDER(sm_conn->sm_role)){ 4420 // responder 4421 if (sm_passkey_used(setup->sm_stk_generation_method)){ 4422 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 4423 // still waiting for passkey 4424 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 4425 break; 4426 } 4427 } 4428 sm_sc_start_calculating_local_confirm(sm_conn); 4429 } else { 4430 // initiator 4431 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 4432 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); 4433 } else { 4434 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 4435 } 4436 } 4437 break; 4438 4439 case SM_SC_W4_PAIRING_RANDOM: 4440 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4441 sm_pdu_received_in_wrong_state(sm_conn); 4442 break; 4443 } 4444 4445 // received random value 4446 reverse_128(&packet[1], setup->sm_peer_nonce); 4447 4448 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4449 // only check for JUST WORK/NC in initiator role OR passkey entry 4450 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4451 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4452 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4453 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4454 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4455 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4456 break; 4457 } 4458 4459 // OOB 4460 if (setup->sm_stk_generation_method == OOB){ 4461 4462 // setup local random, set to zero if remote did not receive our data 4463 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4464 if (IS_RESPONDER(sm_conn->sm_role)){ 4465 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4466 log_info("Reset rb as A does not have OOB data"); 4467 memset(setup->sm_rb, 0, 16); 4468 } else { 4469 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4470 log_info("Use stored rb"); 4471 log_info_hexdump(setup->sm_rb, 16); 4472 } 4473 } else { 4474 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4475 log_info("Reset ra as B does not have OOB data"); 4476 memset(setup->sm_ra, 0, 16); 4477 } else { 4478 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4479 log_info("Use stored ra"); 4480 log_info_hexdump(setup->sm_ra, 16); 4481 } 4482 } 4483 4484 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4485 if (setup->sm_have_oob_data){ 4486 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4487 break; 4488 } 4489 } 4490 4491 // TODO: we only get here for Responder role with JW/NC 4492 sm_sc_state_after_receiving_random(sm_conn); 4493 break; 4494 4495 case SM_SC_W2_CALCULATE_G2: 4496 case SM_SC_W4_CALCULATE_G2: 4497 case SM_SC_W4_CALCULATE_DHKEY: 4498 case SM_SC_W2_CALCULATE_F5_SALT: 4499 case SM_SC_W4_CALCULATE_F5_SALT: 4500 case SM_SC_W2_CALCULATE_F5_MACKEY: 4501 case SM_SC_W4_CALCULATE_F5_MACKEY: 4502 case SM_SC_W2_CALCULATE_F5_LTK: 4503 case SM_SC_W4_CALCULATE_F5_LTK: 4504 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4505 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4506 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4507 case SM_SC_W4_USER_RESPONSE: 4508 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4509 sm_pdu_received_in_wrong_state(sm_conn); 4510 break; 4511 } 4512 // store DHKey Check 4513 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4514 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4515 4516 // have we been only waiting for dhkey check command? 4517 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4518 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4519 } 4520 break; 4521 #endif 4522 4523 #ifdef ENABLE_LE_PERIPHERAL 4524 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4525 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4526 sm_pdu_received_in_wrong_state(sm_conn); 4527 break; 4528 } 4529 4530 // received confirm value 4531 reverse_128(&packet[1], setup->sm_peer_confirm); 4532 4533 #ifdef ENABLE_TESTING_SUPPORT 4534 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4535 log_info("testing_support: reset confirm value"); 4536 memset(setup->sm_peer_confirm, 0, 16); 4537 } 4538 #endif 4539 // notify client to hide shown passkey 4540 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4541 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4542 } 4543 4544 // handle user cancel pairing? 4545 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4546 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4547 break; 4548 } 4549 4550 // wait for user action? 4551 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4552 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4553 break; 4554 } 4555 4556 // calculate and send local_confirm 4557 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); 4558 break; 4559 4560 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4561 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4562 sm_pdu_received_in_wrong_state(sm_conn); 4563 break;; 4564 } 4565 4566 // received random value 4567 reverse_128(&packet[1], setup->sm_peer_random); 4568 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4569 break; 4570 #endif 4571 4572 case SM_PH2_W4_CONNECTION_ENCRYPTED: 4573 case SM_PH3_RECEIVE_KEYS: 4574 switch(sm_pdu_code){ 4575 case SM_CODE_ENCRYPTION_INFORMATION: 4576 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4577 reverse_128(&packet[1], setup->sm_peer_ltk); 4578 break; 4579 4580 case SM_CODE_MASTER_IDENTIFICATION: 4581 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4582 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4583 reverse_64(&packet[3], setup->sm_peer_rand); 4584 break; 4585 4586 case SM_CODE_IDENTITY_INFORMATION: 4587 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4588 reverse_128(&packet[1], setup->sm_peer_irk); 4589 break; 4590 4591 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4592 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4593 setup->sm_peer_addr_type = packet[1]; 4594 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4595 break; 4596 4597 case SM_CODE_SIGNING_INFORMATION: 4598 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4599 reverse_128(&packet[1], setup->sm_peer_csrk); 4600 break; 4601 default: 4602 // Unexpected PDU 4603 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4604 break; 4605 } 4606 // done with key distribution? 4607 if (sm_key_distribution_all_received()){ 4608 4609 sm_key_distribution_handle_all_received(sm_conn); 4610 4611 if (IS_RESPONDER(sm_conn->sm_role)){ 4612 sm_key_distribution_complete_responder(sm_conn); 4613 } else { 4614 if (setup->sm_use_secure_connections){ 4615 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4616 } else { 4617 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); 4618 } 4619 } 4620 } 4621 break; 4622 4623 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4624 case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: 4625 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 4626 sm_pdu_received_in_wrong_state(sm_conn); 4627 break; 4628 } 4629 // store pairing response 4630 (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 4631 4632 // validate encryption key size 4633 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)); 4634 // SC Only mandates 128 bit key size 4635 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4636 sm_conn->sm_actual_encryption_key_size = 0; 4637 } 4638 if (sm_conn->sm_actual_encryption_key_size == 0){ 4639 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4640 break; 4641 } 4642 4643 // prepare key exchange, LTK is derived locally 4644 sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, 4645 sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); 4646 4647 // skip receive if there are none 4648 if (sm_key_distribution_all_received()){ 4649 // distribute keys in run handles 'no keys to send' 4650 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4651 } else { 4652 sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; 4653 } 4654 break; 4655 4656 case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: 4657 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 4658 sm_pdu_received_in_wrong_state(sm_conn); 4659 break; 4660 } 4661 // store pairing request 4662 (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 4663 // validate encryption key size 4664 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)); 4665 // SC Only mandates 128 bit key size 4666 if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { 4667 sm_conn->sm_actual_encryption_key_size = 0; 4668 } 4669 if (sm_conn->sm_actual_encryption_key_size == 0){ 4670 sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); 4671 break; 4672 } 4673 // trigger response 4674 sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; 4675 break; 4676 4677 case SM_BR_EDR_RECEIVE_KEYS: 4678 switch(sm_pdu_code){ 4679 case SM_CODE_IDENTITY_INFORMATION: 4680 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4681 reverse_128(&packet[1], setup->sm_peer_irk); 4682 break; 4683 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4684 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4685 setup->sm_peer_addr_type = packet[1]; 4686 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4687 break; 4688 case SM_CODE_SIGNING_INFORMATION: 4689 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4690 reverse_128(&packet[1], setup->sm_peer_csrk); 4691 break; 4692 default: 4693 // Unexpected PDU 4694 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4695 break; 4696 } 4697 4698 // all keys received 4699 if (sm_key_distribution_all_received()){ 4700 if (IS_RESPONDER(sm_conn->sm_role)){ 4701 // responder -> keys exchanged, derive LE LTK 4702 sm_ctkd_start_from_br_edr(sm_conn); 4703 } else { 4704 // initiator -> send our keys if any 4705 sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; 4706 } 4707 } 4708 break; 4709 #endif 4710 4711 default: 4712 // Unexpected PDU 4713 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4714 sm_pdu_received_in_wrong_state(sm_conn); 4715 break; 4716 } 4717 4718 // try to send next pdu 4719 sm_trigger_run(); 4720 } 4721 4722 // Security Manager Client API 4723 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4724 sm_get_oob_data = get_oob_data_callback; 4725 } 4726 4727 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)){ 4728 sm_get_sc_oob_data = get_sc_oob_data_callback; 4729 } 4730 4731 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)){ 4732 sm_get_ltk_callback = get_ltk_callback; 4733 } 4734 4735 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4736 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4737 } 4738 4739 void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4740 btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4741 } 4742 4743 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4744 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4745 } 4746 4747 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4748 sm_min_encryption_key_size = min_size; 4749 sm_max_encryption_key_size = max_size; 4750 } 4751 4752 void sm_set_authentication_requirements(uint8_t auth_req){ 4753 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4754 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4755 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4756 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4757 } 4758 #endif 4759 sm_auth_req = auth_req; 4760 } 4761 4762 void sm_set_io_capabilities(io_capability_t io_capability){ 4763 sm_io_capabilities = io_capability; 4764 } 4765 4766 #ifdef ENABLE_LE_PERIPHERAL 4767 void sm_set_request_security(int enable){ 4768 sm_slave_request_security = enable; 4769 } 4770 #endif 4771 4772 void sm_set_er(sm_key_t er){ 4773 (void)memcpy(sm_persistent_er, er, 16); 4774 } 4775 4776 void sm_set_ir(sm_key_t ir){ 4777 (void)memcpy(sm_persistent_ir, ir, 16); 4778 } 4779 4780 // Testing support only 4781 void sm_test_set_irk(sm_key_t irk){ 4782 (void)memcpy(sm_persistent_irk, irk, 16); 4783 dkg_state = DKG_CALC_DHK; 4784 test_use_fixed_local_irk = true; 4785 } 4786 4787 void sm_test_use_fixed_local_csrk(void){ 4788 test_use_fixed_local_csrk = true; 4789 } 4790 4791 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4792 static void sm_ec_generated(void * arg){ 4793 UNUSED(arg); 4794 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4795 // trigger pairing if pending for ec key 4796 sm_trigger_run(); 4797 } 4798 static void sm_ec_generate_new_key(void){ 4799 log_info("sm: generate new ec key"); 4800 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4801 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4802 } 4803 #endif 4804 4805 #ifdef ENABLE_TESTING_SUPPORT 4806 void sm_test_set_pairing_failure(int reason){ 4807 test_pairing_failure = reason; 4808 } 4809 #endif 4810 4811 static void sm_state_reset(void) { 4812 #ifdef USE_CMAC_ENGINE 4813 sm_cmac_active = 0; 4814 #endif 4815 dkg_state = DKG_W4_WORKING; 4816 rau_state = RAU_IDLE; 4817 sm_aes128_state = SM_AES128_IDLE; 4818 sm_address_resolution_test = -1; // no private address to resolve yet 4819 sm_address_resolution_ah_calculation_active = 0; 4820 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4821 sm_address_resolution_general_queue = NULL; 4822 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4823 sm_persistent_keys_random_active = false; 4824 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4825 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4826 #endif 4827 } 4828 4829 void sm_init(void){ 4830 4831 if (sm_initialized) return; 4832 4833 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4834 sm_er_ir_set_default(); 4835 4836 // defaults 4837 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4838 | SM_STK_GENERATION_METHOD_OOB 4839 | SM_STK_GENERATION_METHOD_PASSKEY 4840 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4841 4842 sm_max_encryption_key_size = 16; 4843 sm_min_encryption_key_size = 7; 4844 4845 sm_fixed_passkey_in_display_role = 0xffffffffU; 4846 sm_reconstruct_ltk_without_le_device_db_entry = true; 4847 4848 gap_random_adress_update_period = 15 * 60 * 1000L; 4849 4850 test_use_fixed_local_csrk = false; 4851 4852 // other 4853 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4854 4855 // register for HCI Events from HCI 4856 hci_event_callback_registration.callback = &sm_event_packet_handler; 4857 hci_add_event_handler(&hci_event_callback_registration); 4858 4859 // 4860 btstack_crypto_init(); 4861 4862 // init le_device_db 4863 le_device_db_init(); 4864 4865 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4866 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4867 #ifdef ENABLE_CLASSIC 4868 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); 4869 #endif 4870 4871 // state 4872 sm_state_reset(); 4873 4874 sm_initialized = true; 4875 } 4876 4877 void sm_deinit(void){ 4878 sm_initialized = false; 4879 btstack_run_loop_remove_timer(&sm_run_timer); 4880 } 4881 4882 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4883 sm_fixed_passkey_in_display_role = passkey; 4884 } 4885 4886 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4887 sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; 4888 } 4889 4890 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4891 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4892 if (!hci_con) return NULL; 4893 return &hci_con->sm_connection; 4894 } 4895 4896 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 4897 static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ 4898 hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); 4899 if (!hci_con) return NULL; 4900 return &hci_con->sm_connection; 4901 } 4902 #endif 4903 4904 // @deprecated: map onto sm_request_pairing 4905 void sm_send_security_request(hci_con_handle_t con_handle){ 4906 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4907 if (!sm_conn) return; 4908 if (!IS_RESPONDER(sm_conn->sm_role)) return; 4909 sm_request_pairing(con_handle); 4910 } 4911 4912 // request pairing 4913 void sm_request_pairing(hci_con_handle_t con_handle){ 4914 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4915 if (!sm_conn) return; // wrong connection 4916 4917 bool have_ltk; 4918 uint8_t ltk[16]; 4919 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4920 if (IS_RESPONDER(sm_conn->sm_role)){ 4921 switch (sm_conn->sm_engine_state){ 4922 case SM_GENERAL_IDLE: 4923 case SM_RESPONDER_IDLE: 4924 switch (sm_conn->sm_irk_lookup_state){ 4925 case IRK_LOOKUP_SUCCEEDED: 4926 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4927 have_ltk = !sm_is_null_key(ltk); 4928 log_info("have ltk %u", have_ltk); 4929 if (have_ltk){ 4930 sm_conn->sm_pairing_requested = 1; 4931 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4932 sm_reencryption_started(sm_conn); 4933 break; 4934 } 4935 /* fall through */ 4936 4937 case IRK_LOOKUP_FAILED: 4938 sm_conn->sm_pairing_requested = 1; 4939 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4940 sm_pairing_started(sm_conn); 4941 break; 4942 default: 4943 log_info("irk lookup pending"); 4944 sm_conn->sm_pairing_requested = 1; 4945 break; 4946 } 4947 break; 4948 default: 4949 break; 4950 } 4951 } else { 4952 // used as a trigger to start central/master/initiator security procedures 4953 switch (sm_conn->sm_engine_state){ 4954 case SM_INITIATOR_CONNECTED: 4955 switch (sm_conn->sm_irk_lookup_state){ 4956 case IRK_LOOKUP_SUCCEEDED: 4957 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4958 have_ltk = !sm_is_null_key(ltk); 4959 log_info("have ltk %u", have_ltk); 4960 if (have_ltk){ 4961 sm_conn->sm_pairing_requested = 1; 4962 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4963 break; 4964 } 4965 /* fall through */ 4966 4967 case IRK_LOOKUP_FAILED: 4968 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4969 break; 4970 default: 4971 log_info("irk lookup pending"); 4972 sm_conn->sm_pairing_requested = 1; 4973 break; 4974 } 4975 break; 4976 case SM_GENERAL_REENCRYPTION_FAILED: 4977 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4978 break; 4979 case SM_GENERAL_IDLE: 4980 sm_conn->sm_pairing_requested = 1; 4981 break; 4982 default: 4983 break; 4984 } 4985 } 4986 sm_trigger_run(); 4987 } 4988 4989 // called by client app on authorization request 4990 void sm_authorization_decline(hci_con_handle_t con_handle){ 4991 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4992 if (!sm_conn) return; // wrong connection 4993 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4994 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4995 } 4996 4997 void sm_authorization_grant(hci_con_handle_t con_handle){ 4998 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4999 if (!sm_conn) return; // wrong connection 5000 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 5001 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 5002 } 5003 5004 // GAP Bonding API 5005 5006 void sm_bonding_decline(hci_con_handle_t con_handle){ 5007 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5008 if (!sm_conn) return; // wrong connection 5009 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 5010 log_info("decline, state %u", sm_conn->sm_engine_state); 5011 switch(sm_conn->sm_engine_state){ 5012 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5013 case SM_SC_W4_USER_RESPONSE: 5014 case SM_SC_W4_CONFIRMATION: 5015 case SM_SC_W4_PUBLIC_KEY_COMMAND: 5016 #endif 5017 case SM_PH1_W4_USER_RESPONSE: 5018 switch (setup->sm_stk_generation_method){ 5019 case PK_RESP_INPUT: 5020 case PK_INIT_INPUT: 5021 case PK_BOTH_INPUT: 5022 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 5023 break; 5024 case NUMERIC_COMPARISON: 5025 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 5026 break; 5027 case JUST_WORKS: 5028 case OOB: 5029 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 5030 break; 5031 default: 5032 btstack_assert(false); 5033 break; 5034 } 5035 break; 5036 default: 5037 break; 5038 } 5039 sm_trigger_run(); 5040 } 5041 5042 void sm_just_works_confirm(hci_con_handle_t con_handle){ 5043 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5044 if (!sm_conn) return; // wrong connection 5045 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 5046 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5047 if (setup->sm_use_secure_connections){ 5048 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 5049 } else { 5050 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); 5051 } 5052 } 5053 5054 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5055 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5056 sm_sc_prepare_dhkey_check(sm_conn); 5057 } 5058 #endif 5059 5060 sm_trigger_run(); 5061 } 5062 5063 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 5064 // for now, it's the same 5065 sm_just_works_confirm(con_handle); 5066 } 5067 5068 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 5069 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5070 if (!sm_conn) return; // wrong connection 5071 sm_reset_tk(); 5072 big_endian_store_32(setup->sm_tk, 12, passkey); 5073 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 5074 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 5075 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); 5076 } 5077 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5078 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 5079 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 5080 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 5081 sm_sc_start_calculating_local_confirm(sm_conn); 5082 } 5083 #endif 5084 sm_trigger_run(); 5085 } 5086 5087 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 5088 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5089 if (!sm_conn) return; // wrong connection 5090 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 5091 uint8_t num_actions = setup->sm_keypress_notification >> 5; 5092 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 5093 switch (action){ 5094 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 5095 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 5096 flags |= (1u << action); 5097 break; 5098 case SM_KEYPRESS_PASSKEY_CLEARED: 5099 // clear counter, keypress & erased flags + set passkey cleared 5100 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 5101 break; 5102 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 5103 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 5104 // erase actions queued 5105 num_actions--; 5106 if (num_actions == 0u){ 5107 // clear counter, keypress & erased flags 5108 flags &= 0x19u; 5109 } 5110 break; 5111 } 5112 num_actions++; 5113 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 5114 break; 5115 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 5116 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 5117 // enter actions queued 5118 num_actions--; 5119 if (num_actions == 0u){ 5120 // clear counter, keypress & erased flags 5121 flags &= 0x19u; 5122 } 5123 break; 5124 } 5125 num_actions++; 5126 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 5127 break; 5128 default: 5129 break; 5130 } 5131 setup->sm_keypress_notification = (num_actions << 5) | flags; 5132 sm_trigger_run(); 5133 } 5134 5135 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5136 static void sm_handle_random_result_oob(void * arg){ 5137 UNUSED(arg); 5138 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 5139 sm_trigger_run(); 5140 } 5141 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 5142 5143 static btstack_crypto_random_t sm_crypto_random_oob_request; 5144 5145 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 5146 sm_sc_oob_callback = callback; 5147 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 5148 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 5149 return 0; 5150 } 5151 #endif 5152 5153 /** 5154 * @brief Get Identity Resolving state 5155 * @param con_handle 5156 * @return irk_lookup_state_t 5157 */ 5158 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 5159 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5160 if (!sm_conn) return IRK_LOOKUP_IDLE; 5161 return sm_conn->sm_irk_lookup_state; 5162 } 5163 5164 /** 5165 * @brief Identify device in LE Device DB 5166 * @param handle 5167 * @return index from le_device_db or -1 if not found/identified 5168 */ 5169 int sm_le_device_index(hci_con_handle_t con_handle ){ 5170 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5171 if (!sm_conn) return -1; 5172 return sm_conn->sm_le_db_index; 5173 } 5174 5175 static int gap_random_address_type_requires_updates(void){ 5176 switch (gap_random_adress_type){ 5177 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5178 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 5179 return 0; 5180 default: 5181 return 1; 5182 } 5183 } 5184 5185 static uint8_t own_address_type(void){ 5186 switch (gap_random_adress_type){ 5187 case GAP_RANDOM_ADDRESS_TYPE_OFF: 5188 return BD_ADDR_TYPE_LE_PUBLIC; 5189 default: 5190 return BD_ADDR_TYPE_LE_RANDOM; 5191 } 5192 } 5193 5194 // GAP LE API 5195 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 5196 gap_random_address_update_stop(); 5197 gap_random_adress_type = random_address_type; 5198 hci_le_set_own_address_type(own_address_type()); 5199 if (!gap_random_address_type_requires_updates()) return; 5200 gap_random_address_update_start(); 5201 gap_random_address_trigger(); 5202 } 5203 5204 gap_random_address_type_t gap_random_address_get_mode(void){ 5205 return gap_random_adress_type; 5206 } 5207 5208 void gap_random_address_set_update_period(int period_ms){ 5209 gap_random_adress_update_period = period_ms; 5210 if (!gap_random_address_type_requires_updates()) return; 5211 gap_random_address_update_stop(); 5212 gap_random_address_update_start(); 5213 } 5214 5215 void gap_random_address_set(const bd_addr_t addr){ 5216 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 5217 (void)memcpy(sm_random_address, addr, 6); 5218 // assert msb bits are set to '11' 5219 sm_random_address[0] |= 0xc0; 5220 hci_le_random_address_set(sm_random_address); 5221 } 5222 5223 #ifdef ENABLE_LE_PERIPHERAL 5224 /* 5225 * @brief Set Advertisement Paramters 5226 * @param adv_int_min 5227 * @param adv_int_max 5228 * @param adv_type 5229 * @param direct_address_type 5230 * @param direct_address 5231 * @param channel_map 5232 * @param filter_policy 5233 * 5234 * @note own_address_type is used from gap_random_address_set_mode 5235 */ 5236 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 5237 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 5238 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 5239 direct_address_typ, direct_address, channel_map, filter_policy); 5240 } 5241 #endif 5242 5243 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 5244 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 5245 // wrong connection 5246 if (!sm_conn) return 0; 5247 // already encrypted 5248 if (sm_conn->sm_connection_encrypted) return 0; 5249 // irk status? 5250 switch(sm_conn->sm_irk_lookup_state){ 5251 case IRK_LOOKUP_FAILED: 5252 // done, cannot setup encryption 5253 return 0; 5254 case IRK_LOOKUP_SUCCEEDED: 5255 break; 5256 default: 5257 // IR Lookup pending 5258 return 1; 5259 } 5260 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure 5261 if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return 0; 5262 if (sm_conn->sm_role){ 5263 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 5264 } else { 5265 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 5266 } 5267 } 5268 5269 void sm_set_secure_connections_only_mode(bool enable){ 5270 #ifdef ENABLE_LE_SECURE_CONNECTIONS 5271 sm_sc_only_mode = enable; 5272 #else 5273 // SC Only mode not possible without support for SC 5274 btstack_assert(enable == false); 5275 #endif 5276 } 5277 5278 const uint8_t * gap_get_persistent_irk(void){ 5279 return sm_persistent_irk; 5280 } 5281 5282 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 5283 uint16_t i; 5284 for (i=0; i < le_device_db_max_count(); i++){ 5285 bd_addr_t entry_address; 5286 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 5287 le_device_db_info(i, &entry_address_type, entry_address, NULL); 5288 // skip unused entries 5289 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 5290 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 5291 sm_remove_le_device_db_entry(i); 5292 break; 5293 } 5294 } 5295 } 5296