1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <stdio.h> 41 #include <string.h> 42 #include <inttypes.h> 43 44 #include "ble/le_device_db.h" 45 #include "ble/core.h" 46 #include "ble/sm.h" 47 #include "bluetooth_company_id.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "gap.h" 53 #include "hci.h" 54 #include "hci_dump.h" 55 #include "l2cap.h" 56 57 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 58 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 59 #endif 60 61 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 62 #define IS_RESPONDER(role) (role) 63 #else 64 #ifdef ENABLE_LE_CENTRAL 65 // only central - never responder (avoid 'unused variable' warnings) 66 #define IS_RESPONDER(role) (0 && role) 67 #else 68 // only peripheral - always responder (avoid 'unused variable' warnings) 69 #define IS_RESPONDER(role) (1 || role) 70 #endif 71 #endif 72 73 #ifdef ENABLE_LE_SECURE_CONNECTIONS 74 // assert SM Public Key can be sent/received 75 #if HCI_ACL_PAYLOAD_SIZE < 69 76 #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" 77 #endif 78 79 // configure ECC implementations 80 #ifdef ENABLE_LE_SECURE_CONNECTIONS 81 #if defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS) && defined(HAVE_MBEDTLS_ECC_P256) 82 #error "If you already have mbedTLS (HAVE_MBEDTLS_ECC_P256), please disable uECC (USE_MICRO_ECC_FOR_ECDH) in bstack_config.h" 83 #endif 84 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS 85 #define USE_SOFTWARE_ECDH_IMPLEMENTATION 86 #define USE_MICRO_ECC_FOR_ECDH 87 #endif 88 #ifdef HAVE_MBEDTLS_ECC_P256 89 #define USE_SOFTWARE_ECDH_IMPLEMENTATION 90 #define USE_MBEDTLS_FOR_ECDH 91 #endif 92 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 93 94 // Software ECDH implementation provided by micro-ecc 95 #ifdef USE_MICRO_ECC_FOR_ECDH 96 #include "uECC.h" 97 #endif 98 #endif 99 100 // Software ECDH implementation provided by mbedTLS 101 #ifdef USE_MBEDTLS_FOR_ECDH 102 #include "mbedtls/config.h" 103 #include "mbedtls/platform.h" 104 #include "mbedtls/ecp.h" 105 #endif 106 107 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 108 #define ENABLE_CMAC_ENGINE 109 #endif 110 111 // 112 // SM internal types and globals 113 // 114 115 typedef enum { 116 DKG_W4_WORKING, 117 DKG_CALC_IRK, 118 DKG_W4_IRK, 119 DKG_CALC_DHK, 120 DKG_W4_DHK, 121 DKG_READY 122 } derived_key_generation_t; 123 124 typedef enum { 125 RAU_W4_WORKING, 126 RAU_IDLE, 127 RAU_GET_RANDOM, 128 RAU_W4_RANDOM, 129 RAU_GET_ENC, 130 RAU_W4_ENC, 131 RAU_SET_ADDRESS, 132 } random_address_update_t; 133 134 typedef enum { 135 CMAC_IDLE, 136 CMAC_CALC_SUBKEYS, 137 CMAC_W4_SUBKEYS, 138 CMAC_CALC_MI, 139 CMAC_W4_MI, 140 CMAC_CALC_MLAST, 141 CMAC_W4_MLAST 142 } cmac_state_t; 143 144 typedef enum { 145 JUST_WORKS, 146 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 147 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 148 OK_BOTH_INPUT, // Only input on both, both input PK 149 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 150 OOB // OOB available on both sides 151 } stk_generation_method_t; 152 153 typedef enum { 154 SM_USER_RESPONSE_IDLE, 155 SM_USER_RESPONSE_PENDING, 156 SM_USER_RESPONSE_CONFIRM, 157 SM_USER_RESPONSE_PASSKEY, 158 SM_USER_RESPONSE_DECLINE 159 } sm_user_response_t; 160 161 typedef enum { 162 SM_AES128_IDLE, 163 SM_AES128_ACTIVE 164 } sm_aes128_state_t; 165 166 typedef enum { 167 ADDRESS_RESOLUTION_IDLE, 168 ADDRESS_RESOLUTION_GENERAL, 169 ADDRESS_RESOLUTION_FOR_CONNECTION, 170 } address_resolution_mode_t; 171 172 typedef enum { 173 ADDRESS_RESOLUTION_SUCEEDED, 174 ADDRESS_RESOLUTION_FAILED, 175 } address_resolution_event_t; 176 177 typedef enum { 178 EC_KEY_GENERATION_IDLE, 179 EC_KEY_GENERATION_ACTIVE, 180 EC_KEY_GENERATION_W4_KEY, 181 EC_KEY_GENERATION_DONE, 182 } ec_key_generation_state_t; 183 184 typedef enum { 185 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 186 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 187 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 188 } sm_state_var_t; 189 190 typedef uint8_t sm_key24_t[3]; 191 typedef uint8_t sm_key56_t[7]; 192 typedef uint8_t sm_key256_t[32]; 193 194 // 195 // GLOBAL DATA 196 // 197 198 static uint8_t test_use_fixed_local_csrk; 199 200 #ifdef ENABLE_TESTING_SUPPORT 201 static uint8_t test_pairing_failure; 202 #endif 203 204 // configuration 205 static uint8_t sm_accepted_stk_generation_methods; 206 static uint8_t sm_max_encryption_key_size; 207 static uint8_t sm_min_encryption_key_size; 208 static uint8_t sm_auth_req = 0; 209 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 210 static uint8_t sm_slave_request_security; 211 static uint32_t sm_fixed_passkey_in_display_role; 212 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 213 #ifdef ENABLE_LE_SECURE_CONNECTIONS 214 static uint8_t sm_have_ec_keypair; 215 #endif 216 217 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 218 static sm_key_t sm_persistent_er; 219 static sm_key_t sm_persistent_ir; 220 221 // derived from sm_persistent_ir 222 static sm_key_t sm_persistent_dhk; 223 static sm_key_t sm_persistent_irk; 224 static uint8_t sm_persistent_irk_ready = 0; // used for testing 225 static derived_key_generation_t dkg_state; 226 227 // derived from sm_persistent_er 228 // .. 229 230 // random address update 231 static random_address_update_t rau_state; 232 static bd_addr_t sm_random_address; 233 234 // CMAC Calculation: General 235 #ifdef ENABLE_CMAC_ENGINE 236 static cmac_state_t sm_cmac_state; 237 static uint16_t sm_cmac_message_len; 238 static sm_key_t sm_cmac_k; 239 static sm_key_t sm_cmac_x; 240 static sm_key_t sm_cmac_m_last; 241 static uint8_t sm_cmac_block_current; 242 static uint8_t sm_cmac_block_count; 243 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 244 static void (*sm_cmac_done_handler)(uint8_t * hash); 245 #endif 246 247 // CMAC for ATT Signed Writes 248 #ifdef ENABLE_LE_SIGNED_WRITE 249 static uint8_t sm_cmac_header[3]; 250 static const uint8_t * sm_cmac_message; 251 static uint8_t sm_cmac_sign_counter[4]; 252 #endif 253 254 // CMAC for Secure Connection functions 255 #ifdef ENABLE_LE_SECURE_CONNECTIONS 256 static sm_connection_t * sm_cmac_connection; 257 static uint8_t sm_cmac_sc_buffer[80]; 258 #endif 259 260 // resolvable private address lookup / CSRK calculation 261 static int sm_address_resolution_test; 262 static int sm_address_resolution_ah_calculation_active; 263 static uint8_t sm_address_resolution_addr_type; 264 static bd_addr_t sm_address_resolution_address; 265 static void * sm_address_resolution_context; 266 static address_resolution_mode_t sm_address_resolution_mode; 267 static btstack_linked_list_t sm_address_resolution_general_queue; 268 269 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 270 static sm_aes128_state_t sm_aes128_state; 271 static void * sm_aes128_context; 272 273 // use aes128 provided by MCU - not needed usually 274 #ifdef HAVE_AES128 275 static uint8_t aes128_result_flipped[16]; 276 static btstack_timer_source_t aes128_timer; 277 void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result); 278 #endif 279 280 // random engine. store context (ususally sm_connection_t) 281 static void * sm_random_context; 282 283 // to receive hci events 284 static btstack_packet_callback_registration_t hci_event_callback_registration; 285 286 /* to dispatch sm event */ 287 static btstack_linked_list_t sm_event_handlers; 288 289 // LE Secure Connections 290 #ifdef ENABLE_LE_SECURE_CONNECTIONS 291 static ec_key_generation_state_t ec_key_generation_state; 292 static uint8_t ec_d[32]; 293 static uint8_t ec_q[64]; 294 #endif 295 296 // Software ECDH implementation provided by mbedtls 297 #ifdef USE_MBEDTLS_FOR_ECDH 298 static mbedtls_ecp_group mbedtls_ec_group; 299 #endif 300 301 // 302 // Volume 3, Part H, Chapter 24 303 // "Security shall be initiated by the Security Manager in the device in the master role. 304 // The device in the slave role shall be the responding device." 305 // -> master := initiator, slave := responder 306 // 307 308 // data needed for security setup 309 typedef struct sm_setup_context { 310 311 btstack_timer_source_t sm_timeout; 312 313 // used in all phases 314 uint8_t sm_pairing_failed_reason; 315 316 // user response, (Phase 1 and/or 2) 317 uint8_t sm_user_response; 318 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 319 320 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 321 int sm_key_distribution_send_set; 322 int sm_key_distribution_received_set; 323 324 // Phase 2 (Pairing over SMP) 325 stk_generation_method_t sm_stk_generation_method; 326 sm_key_t sm_tk; 327 uint8_t sm_use_secure_connections; 328 329 sm_key_t sm_c1_t3_value; // c1 calculation 330 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 331 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 332 sm_key_t sm_local_random; 333 sm_key_t sm_local_confirm; 334 sm_key_t sm_peer_random; 335 sm_key_t sm_peer_confirm; 336 uint8_t sm_m_addr_type; // address and type can be removed 337 uint8_t sm_s_addr_type; // '' 338 bd_addr_t sm_m_address; // '' 339 bd_addr_t sm_s_address; // '' 340 sm_key_t sm_ltk; 341 342 uint8_t sm_state_vars; 343 #ifdef ENABLE_LE_SECURE_CONNECTIONS 344 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 345 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 346 sm_key_t sm_local_nonce; // might be combined with sm_local_random 347 sm_key_t sm_dhkey; 348 sm_key_t sm_peer_dhkey_check; 349 sm_key_t sm_local_dhkey_check; 350 sm_key_t sm_ra; 351 sm_key_t sm_rb; 352 sm_key_t sm_t; // used for f5 and h6 353 sm_key_t sm_mackey; 354 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 355 #endif 356 357 // Phase 3 358 359 // key distribution, we generate 360 uint16_t sm_local_y; 361 uint16_t sm_local_div; 362 uint16_t sm_local_ediv; 363 uint8_t sm_local_rand[8]; 364 sm_key_t sm_local_ltk; 365 sm_key_t sm_local_csrk; 366 sm_key_t sm_local_irk; 367 // sm_local_address/addr_type not needed 368 369 // key distribution, received from peer 370 uint16_t sm_peer_y; 371 uint16_t sm_peer_div; 372 uint16_t sm_peer_ediv; 373 uint8_t sm_peer_rand[8]; 374 sm_key_t sm_peer_ltk; 375 sm_key_t sm_peer_irk; 376 sm_key_t sm_peer_csrk; 377 uint8_t sm_peer_addr_type; 378 bd_addr_t sm_peer_address; 379 380 } sm_setup_context_t; 381 382 // 383 static sm_setup_context_t the_setup; 384 static sm_setup_context_t * setup = &the_setup; 385 386 // active connection - the one for which the_setup is used for 387 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 388 389 // @returns 1 if oob data is available 390 // stores oob data in provided 16 byte buffer if not null 391 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 392 393 // horizontal: initiator capabilities 394 // vertial: responder capabilities 395 static const stk_generation_method_t stk_generation_method [5] [5] = { 396 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 397 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 398 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 399 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 400 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 401 }; 402 403 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 404 #ifdef ENABLE_LE_SECURE_CONNECTIONS 405 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 406 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 407 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 408 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 409 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 410 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 411 }; 412 #endif 413 414 static void sm_run(void); 415 static void sm_done_for_handle(hci_con_handle_t con_handle); 416 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 417 static inline int sm_calc_actual_encryption_key_size(int other); 418 static int sm_validate_stk_generation_method(void); 419 static void sm_handle_encryption_result(uint8_t * data); 420 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 421 422 static void log_info_hex16(const char * name, uint16_t value){ 423 log_info("%-6s 0x%04x", name, value); 424 } 425 426 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 427 // return packet[0]; 428 // } 429 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 430 return packet[1]; 431 } 432 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 433 return packet[2]; 434 } 435 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 436 return packet[3]; 437 } 438 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 439 return packet[4]; 440 } 441 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 442 return packet[5]; 443 } 444 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 445 return packet[6]; 446 } 447 448 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 449 packet[0] = code; 450 } 451 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 452 packet[1] = io_capability; 453 } 454 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 455 packet[2] = oob_data_flag; 456 } 457 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 458 packet[3] = auth_req; 459 } 460 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 461 packet[4] = max_encryption_key_size; 462 } 463 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 464 packet[5] = initiator_key_distribution; 465 } 466 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 467 packet[6] = responder_key_distribution; 468 } 469 470 // @returns 1 if all bytes are 0 471 static int sm_is_null(uint8_t * data, int size){ 472 int i; 473 for (i=0; i < size ; i++){ 474 if (data[i]) return 0; 475 } 476 return 1; 477 } 478 479 static int sm_is_null_random(uint8_t random[8]){ 480 return sm_is_null(random, 8); 481 } 482 483 static int sm_is_null_key(uint8_t * key){ 484 return sm_is_null(key, 16); 485 } 486 487 // Key utils 488 static void sm_reset_tk(void){ 489 int i; 490 for (i=0;i<16;i++){ 491 setup->sm_tk[i] = 0; 492 } 493 } 494 495 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 496 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 497 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 498 int i; 499 for (i = max_encryption_size ; i < 16 ; i++){ 500 key[15-i] = 0; 501 } 502 } 503 504 // SMP Timeout implementation 505 506 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 507 // the Security Manager Timer shall be reset and started. 508 // 509 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 510 // 511 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 512 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 513 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 514 // established. 515 516 static void sm_timeout_handler(btstack_timer_source_t * timer){ 517 log_info("SM timeout"); 518 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 519 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 520 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 521 sm_done_for_handle(sm_conn->sm_handle); 522 523 // trigger handling of next ready connection 524 sm_run(); 525 } 526 static void sm_timeout_start(sm_connection_t * sm_conn){ 527 btstack_run_loop_remove_timer(&setup->sm_timeout); 528 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 529 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 530 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 531 btstack_run_loop_add_timer(&setup->sm_timeout); 532 } 533 static void sm_timeout_stop(void){ 534 btstack_run_loop_remove_timer(&setup->sm_timeout); 535 } 536 static void sm_timeout_reset(sm_connection_t * sm_conn){ 537 sm_timeout_stop(); 538 sm_timeout_start(sm_conn); 539 } 540 541 // end of sm timeout 542 543 // GAP Random Address updates 544 static gap_random_address_type_t gap_random_adress_type; 545 static btstack_timer_source_t gap_random_address_update_timer; 546 static uint32_t gap_random_adress_update_period; 547 548 static void gap_random_address_trigger(void){ 549 if (rau_state != RAU_IDLE) return; 550 log_info("gap_random_address_trigger"); 551 rau_state = RAU_GET_RANDOM; 552 sm_run(); 553 } 554 555 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 556 UNUSED(timer); 557 558 log_info("GAP Random Address Update due"); 559 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 560 btstack_run_loop_add_timer(&gap_random_address_update_timer); 561 gap_random_address_trigger(); 562 } 563 564 static void gap_random_address_update_start(void){ 565 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 566 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 567 btstack_run_loop_add_timer(&gap_random_address_update_timer); 568 } 569 570 static void gap_random_address_update_stop(void){ 571 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 572 } 573 574 575 static void sm_random_start(void * context){ 576 sm_random_context = context; 577 hci_send_cmd(&hci_le_rand); 578 } 579 580 #ifdef HAVE_AES128 581 static void aes128_completed(btstack_timer_source_t * ts){ 582 UNUSED(ts); 583 sm_handle_encryption_result(&aes128_result_flipped[0]); 584 sm_run(); 585 } 586 #endif 587 588 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 589 // context is made availabe to aes128 result handler by this 590 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 591 sm_aes128_state = SM_AES128_ACTIVE; 592 sm_aes128_context = context; 593 594 #ifdef HAVE_AES128 595 // calc result directly 596 sm_key_t result; 597 btstack_aes128_calc(key, plaintext, result); 598 599 // log 600 log_info_key("key", key); 601 log_info_key("txt", plaintext); 602 log_info_key("res", result); 603 604 // flip 605 reverse_128(&result[0], &aes128_result_flipped[0]); 606 607 // deliver via timer 608 btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed); 609 btstack_run_loop_set_timer(&aes128_timer, 0); // no delay 610 btstack_run_loop_add_timer(&aes128_timer); 611 #else 612 sm_key_t key_flipped, plaintext_flipped; 613 reverse_128(key, key_flipped); 614 reverse_128(plaintext, plaintext_flipped); 615 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 616 #endif 617 } 618 619 // ah(k,r) helper 620 // r = padding || r 621 // r - 24 bit value 622 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 623 // r'= padding || r 624 memset(r_prime, 0, 16); 625 memcpy(&r_prime[13], r, 3); 626 } 627 628 // d1 helper 629 // d' = padding || r || d 630 // d,r - 16 bit values 631 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 632 // d'= padding || r || d 633 memset(d1_prime, 0, 16); 634 big_endian_store_16(d1_prime, 12, r); 635 big_endian_store_16(d1_prime, 14, d); 636 } 637 638 // dm helper 639 // r’ = padding || r 640 // r - 64 bit value 641 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 642 memset(r_prime, 0, 16); 643 memcpy(&r_prime[8], r, 8); 644 } 645 646 // calculate arguments for first AES128 operation in C1 function 647 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){ 648 649 // p1 = pres || preq || rat’ || iat’ 650 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 651 // cant octet of pres becomes the most significant octet of p1. 652 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 653 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 654 // p1 is 0x05000800000302070710000001010001." 655 656 sm_key_t p1; 657 reverse_56(pres, &p1[0]); 658 reverse_56(preq, &p1[7]); 659 p1[14] = rat; 660 p1[15] = iat; 661 log_info_key("p1", p1); 662 log_info_key("r", r); 663 664 // t1 = r xor p1 665 int i; 666 for (i=0;i<16;i++){ 667 t1[i] = r[i] ^ p1[i]; 668 } 669 log_info_key("t1", t1); 670 } 671 672 // calculate arguments for second AES128 operation in C1 function 673 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 674 // p2 = padding || ia || ra 675 // "The least significant octet of ra becomes the least significant octet of p2 and 676 // the most significant octet of padding becomes the most significant octet of p2. 677 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 678 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 679 680 sm_key_t p2; 681 memset(p2, 0, 16); 682 memcpy(&p2[4], ia, 6); 683 memcpy(&p2[10], ra, 6); 684 log_info_key("p2", p2); 685 686 // c1 = e(k, t2_xor_p2) 687 int i; 688 for (i=0;i<16;i++){ 689 t3[i] = t2[i] ^ p2[i]; 690 } 691 log_info_key("t3", t3); 692 } 693 694 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 695 log_info_key("r1", r1); 696 log_info_key("r2", r2); 697 memcpy(&r_prime[8], &r2[8], 8); 698 memcpy(&r_prime[0], &r1[8], 8); 699 } 700 701 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 702 UNUSED(channel); 703 704 // log event 705 hci_dump_packet(packet_type, 1, packet, size); 706 // dispatch to all event handlers 707 btstack_linked_list_iterator_t it; 708 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 709 while (btstack_linked_list_iterator_has_next(&it)){ 710 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 711 entry->callback(packet_type, 0, packet, size); 712 } 713 } 714 715 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){ 716 event[0] = type; 717 event[1] = event_size - 2; 718 little_endian_store_16(event, 2, con_handle); 719 event[4] = addr_type; 720 reverse_bd_addr(address, &event[5]); 721 } 722 723 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 724 uint8_t event[11]; 725 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 726 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 727 } 728 729 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 730 uint8_t event[15]; 731 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 732 little_endian_store_32(event, 11, passkey); 733 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 734 } 735 736 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){ 737 // fetch addr and addr type from db 738 bd_addr_t identity_address; 739 int identity_address_type; 740 le_device_db_info(index, &identity_address_type, identity_address, NULL); 741 742 uint8_t event[19]; 743 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 744 event[11] = identity_address_type; 745 reverse_bd_addr(identity_address, &event[12]); 746 event[18] = index; 747 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 748 } 749 750 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){ 751 uint8_t event[12]; 752 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 753 event[11] = status; 754 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 755 } 756 757 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 758 uint8_t event[13]; 759 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 760 event[11] = status; 761 event[12] = reason; 762 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 763 } 764 765 // decide on stk generation based on 766 // - pairing request 767 // - io capabilities 768 // - OOB data availability 769 static void sm_setup_tk(void){ 770 771 // default: just works 772 setup->sm_stk_generation_method = JUST_WORKS; 773 774 #ifdef ENABLE_LE_SECURE_CONNECTIONS 775 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 776 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 777 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 778 memset(setup->sm_ra, 0, 16); 779 memset(setup->sm_rb, 0, 16); 780 #else 781 setup->sm_use_secure_connections = 0; 782 #endif 783 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 784 785 // If both devices have not set the MITM option in the Authentication Requirements 786 // Flags, then the IO capabilities shall be ignored and the Just Works association 787 // model shall be used. 788 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 789 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 790 log_info("SM: MITM not required by both -> JUST WORKS"); 791 return; 792 } 793 794 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 795 796 // If both devices have out of band authentication data, then the Authentication 797 // Requirements Flags shall be ignored when selecting the pairing method and the 798 // Out of Band pairing method shall be used. 799 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 800 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 801 log_info("SM: have OOB data"); 802 log_info_key("OOB", setup->sm_tk); 803 setup->sm_stk_generation_method = OOB; 804 return; 805 } 806 807 // Reset TK as it has been setup in sm_init_setup 808 sm_reset_tk(); 809 810 // Also use just works if unknown io capabilites 811 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)){ 812 return; 813 } 814 815 // Otherwise the IO capabilities of the devices shall be used to determine the 816 // pairing method as defined in Table 2.4. 817 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 818 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 819 820 #ifdef ENABLE_LE_SECURE_CONNECTIONS 821 // table not define by default 822 if (setup->sm_use_secure_connections){ 823 generation_method = stk_generation_method_with_secure_connection; 824 } 825 #endif 826 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)]; 827 828 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 829 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); 830 } 831 832 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 833 int flags = 0; 834 if (key_set & SM_KEYDIST_ENC_KEY){ 835 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 836 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 837 } 838 if (key_set & SM_KEYDIST_ID_KEY){ 839 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 840 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 841 } 842 if (key_set & SM_KEYDIST_SIGN){ 843 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 844 } 845 return flags; 846 } 847 848 static void sm_setup_key_distribution(uint8_t key_set){ 849 setup->sm_key_distribution_received_set = 0; 850 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 851 } 852 853 // CSRK Key Lookup 854 855 856 static int sm_address_resolution_idle(void){ 857 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 858 } 859 860 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){ 861 memcpy(sm_address_resolution_address, addr, 6); 862 sm_address_resolution_addr_type = addr_type; 863 sm_address_resolution_test = 0; 864 sm_address_resolution_mode = mode; 865 sm_address_resolution_context = context; 866 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 867 } 868 869 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 870 // check if already in list 871 btstack_linked_list_iterator_t it; 872 sm_lookup_entry_t * entry; 873 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 874 while(btstack_linked_list_iterator_has_next(&it)){ 875 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 876 if (entry->address_type != address_type) continue; 877 if (memcmp(entry->address, address, 6)) continue; 878 // already in list 879 return BTSTACK_BUSY; 880 } 881 entry = btstack_memory_sm_lookup_entry_get(); 882 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 883 entry->address_type = (bd_addr_type_t) address_type; 884 memcpy(entry->address, address, 6); 885 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 886 sm_run(); 887 return 0; 888 } 889 890 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 891 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 892 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 893 } 894 static inline void dkg_next_state(void){ 895 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 896 } 897 static inline void rau_next_state(void){ 898 rau_state = (random_address_update_t) (((int)rau_state) + 1); 899 } 900 901 // CMAC calculation using AES Engine 902 #ifdef ENABLE_CMAC_ENGINE 903 904 static inline void sm_cmac_next_state(void){ 905 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 906 } 907 908 static int sm_cmac_last_block_complete(void){ 909 if (sm_cmac_message_len == 0) return 0; 910 return (sm_cmac_message_len & 0x0f) == 0; 911 } 912 913 int sm_cmac_ready(void){ 914 return sm_cmac_state == CMAC_IDLE; 915 } 916 917 // generic cmac calculation 918 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 919 // Generalized CMAC 920 memcpy(sm_cmac_k, key, 16); 921 memset(sm_cmac_x, 0, 16); 922 sm_cmac_block_current = 0; 923 sm_cmac_message_len = message_len; 924 sm_cmac_done_handler = done_callback; 925 sm_cmac_get_byte = get_byte_callback; 926 927 // step 2: n := ceil(len/const_Bsize); 928 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 929 930 // step 3: .. 931 if (sm_cmac_block_count==0){ 932 sm_cmac_block_count = 1; 933 } 934 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 935 936 // first, we need to compute l for k1, k2, and m_last 937 sm_cmac_state = CMAC_CALC_SUBKEYS; 938 939 // let's go 940 sm_run(); 941 } 942 #endif 943 944 // cmac for ATT Message signing 945 #ifdef ENABLE_LE_SIGNED_WRITE 946 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 947 if (offset >= sm_cmac_message_len) { 948 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 949 return 0; 950 } 951 952 offset = sm_cmac_message_len - 1 - offset; 953 954 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 955 if (offset < 3){ 956 return sm_cmac_header[offset]; 957 } 958 int actual_message_len_incl_header = sm_cmac_message_len - 4; 959 if (offset < actual_message_len_incl_header){ 960 return sm_cmac_message[offset - 3]; 961 } 962 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 963 } 964 965 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)){ 966 // ATT Message Signing 967 sm_cmac_header[0] = opcode; 968 little_endian_store_16(sm_cmac_header, 1, con_handle); 969 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 970 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 971 sm_cmac_message = message; 972 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 973 } 974 #endif 975 976 #ifdef ENABLE_CMAC_ENGINE 977 static void sm_cmac_handle_aes_engine_ready(void){ 978 switch (sm_cmac_state){ 979 case CMAC_CALC_SUBKEYS: { 980 sm_key_t const_zero; 981 memset(const_zero, 0, 16); 982 sm_cmac_next_state(); 983 sm_aes128_start(sm_cmac_k, const_zero, NULL); 984 break; 985 } 986 case CMAC_CALC_MI: { 987 int j; 988 sm_key_t y; 989 for (j=0;j<16;j++){ 990 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 991 } 992 sm_cmac_block_current++; 993 sm_cmac_next_state(); 994 sm_aes128_start(sm_cmac_k, y, NULL); 995 break; 996 } 997 case CMAC_CALC_MLAST: { 998 int i; 999 sm_key_t y; 1000 for (i=0;i<16;i++){ 1001 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1002 } 1003 log_info_key("Y", y); 1004 sm_cmac_block_current++; 1005 sm_cmac_next_state(); 1006 sm_aes128_start(sm_cmac_k, y, NULL); 1007 break; 1008 } 1009 default: 1010 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1011 break; 1012 } 1013 } 1014 1015 // CMAC Implementation using AES128 engine 1016 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1017 int i; 1018 int carry = 0; 1019 for (i=len-1; i >= 0 ; i--){ 1020 int new_carry = data[i] >> 7; 1021 data[i] = data[i] << 1 | carry; 1022 carry = new_carry; 1023 } 1024 } 1025 1026 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1027 switch (sm_cmac_state){ 1028 case CMAC_W4_SUBKEYS: { 1029 sm_key_t k1; 1030 memcpy(k1, data, 16); 1031 sm_shift_left_by_one_bit_inplace(16, k1); 1032 if (data[0] & 0x80){ 1033 k1[15] ^= 0x87; 1034 } 1035 sm_key_t k2; 1036 memcpy(k2, k1, 16); 1037 sm_shift_left_by_one_bit_inplace(16, k2); 1038 if (k1[0] & 0x80){ 1039 k2[15] ^= 0x87; 1040 } 1041 1042 log_info_key("k", sm_cmac_k); 1043 log_info_key("k1", k1); 1044 log_info_key("k2", k2); 1045 1046 // step 4: set m_last 1047 int i; 1048 if (sm_cmac_last_block_complete()){ 1049 for (i=0;i<16;i++){ 1050 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1051 } 1052 } else { 1053 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1054 for (i=0;i<16;i++){ 1055 if (i < valid_octets_in_last_block){ 1056 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1057 continue; 1058 } 1059 if (i == valid_octets_in_last_block){ 1060 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1061 continue; 1062 } 1063 sm_cmac_m_last[i] = k2[i]; 1064 } 1065 } 1066 1067 // next 1068 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1069 break; 1070 } 1071 case CMAC_W4_MI: 1072 memcpy(sm_cmac_x, data, 16); 1073 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1074 break; 1075 case CMAC_W4_MLAST: 1076 // done 1077 log_info("Setting CMAC Engine to IDLE"); 1078 sm_cmac_state = CMAC_IDLE; 1079 log_info_key("CMAC", data); 1080 sm_cmac_done_handler(data); 1081 break; 1082 default: 1083 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1084 break; 1085 } 1086 } 1087 #endif 1088 1089 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1090 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1091 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1092 switch (setup->sm_stk_generation_method){ 1093 case PK_RESP_INPUT: 1094 if (IS_RESPONDER(sm_conn->sm_role)){ 1095 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1096 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1097 } else { 1098 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1099 } 1100 break; 1101 case PK_INIT_INPUT: 1102 if (IS_RESPONDER(sm_conn->sm_role)){ 1103 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1104 } else { 1105 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1106 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1107 } 1108 break; 1109 case OK_BOTH_INPUT: 1110 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1111 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1112 break; 1113 case NK_BOTH_INPUT: 1114 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1115 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1116 break; 1117 case JUST_WORKS: 1118 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1119 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1120 break; 1121 case OOB: 1122 // client already provided OOB data, let's skip notification. 1123 break; 1124 } 1125 } 1126 1127 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1128 int recv_flags; 1129 if (IS_RESPONDER(sm_conn->sm_role)){ 1130 // slave / responder 1131 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1132 } else { 1133 // master / initiator 1134 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1135 } 1136 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1137 return recv_flags == setup->sm_key_distribution_received_set; 1138 } 1139 1140 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1141 if (sm_active_connection_handle == con_handle){ 1142 sm_timeout_stop(); 1143 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1144 log_info("sm: connection 0x%x released setup context", con_handle); 1145 } 1146 } 1147 1148 static int sm_key_distribution_flags_for_auth_req(void){ 1149 1150 int flags = SM_KEYDIST_ID_KEY; 1151 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1152 // encryption and signing information only if bonding requested 1153 flags |= SM_KEYDIST_ENC_KEY; 1154 #ifdef ENABLE_LE_SIGNED_WRITE 1155 flags |= SM_KEYDIST_SIGN; 1156 #endif 1157 } 1158 return flags; 1159 } 1160 1161 static void sm_reset_setup(void){ 1162 // fill in sm setup 1163 setup->sm_state_vars = 0; 1164 setup->sm_keypress_notification = 0; 1165 sm_reset_tk(); 1166 } 1167 1168 static void sm_init_setup(sm_connection_t * sm_conn){ 1169 1170 // fill in sm setup 1171 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1172 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1173 1174 // query client for OOB data 1175 int have_oob_data = 0; 1176 if (sm_get_oob_data) { 1177 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1178 } 1179 1180 sm_pairing_packet_t * local_packet; 1181 if (IS_RESPONDER(sm_conn->sm_role)){ 1182 // slave 1183 local_packet = &setup->sm_s_pres; 1184 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1185 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1186 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1187 } else { 1188 // master 1189 local_packet = &setup->sm_m_preq; 1190 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1191 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1192 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1193 1194 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1195 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1196 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1197 } 1198 1199 uint8_t auth_req = sm_auth_req; 1200 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1201 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1202 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1203 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1204 } 1205 1206 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1207 1208 sm_pairing_packet_t * remote_packet; 1209 int remote_key_request; 1210 if (IS_RESPONDER(sm_conn->sm_role)){ 1211 // slave / responder 1212 remote_packet = &setup->sm_m_preq; 1213 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1214 } else { 1215 // master / initiator 1216 remote_packet = &setup->sm_s_pres; 1217 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1218 } 1219 1220 // check key size 1221 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1222 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1223 1224 // decide on STK generation method 1225 sm_setup_tk(); 1226 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1227 1228 // check if STK generation method is acceptable by client 1229 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1230 1231 // identical to responder 1232 sm_setup_key_distribution(remote_key_request); 1233 1234 // JUST WORKS doens't provide authentication 1235 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1236 1237 return 0; 1238 } 1239 1240 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1241 1242 // cache and reset context 1243 int matched_device_id = sm_address_resolution_test; 1244 address_resolution_mode_t mode = sm_address_resolution_mode; 1245 void * context = sm_address_resolution_context; 1246 1247 // reset context 1248 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1249 sm_address_resolution_context = NULL; 1250 sm_address_resolution_test = -1; 1251 hci_con_handle_t con_handle = 0; 1252 1253 sm_connection_t * sm_connection; 1254 #ifdef ENABLE_LE_CENTRAL 1255 sm_key_t ltk; 1256 #endif 1257 switch (mode){ 1258 case ADDRESS_RESOLUTION_GENERAL: 1259 break; 1260 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1261 sm_connection = (sm_connection_t *) context; 1262 con_handle = sm_connection->sm_handle; 1263 switch (event){ 1264 case ADDRESS_RESOLUTION_SUCEEDED: 1265 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1266 sm_connection->sm_le_db_index = matched_device_id; 1267 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1268 if (sm_connection->sm_role) { 1269 // LTK request received before, IRK required -> start LTK calculation 1270 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1271 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1272 } 1273 break; 1274 } 1275 #ifdef ENABLE_LE_CENTRAL 1276 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1277 sm_connection->sm_security_request_received = 0; 1278 sm_connection->sm_pairing_requested = 0; 1279 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1280 if (!sm_is_null_key(ltk)){ 1281 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1282 } else { 1283 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1284 } 1285 #endif 1286 break; 1287 case ADDRESS_RESOLUTION_FAILED: 1288 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1289 if (sm_connection->sm_role) { 1290 // LTK request received before, IRK required -> negative LTK reply 1291 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1292 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1293 } 1294 break; 1295 } 1296 #ifdef ENABLE_LE_CENTRAL 1297 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1298 sm_connection->sm_security_request_received = 0; 1299 sm_connection->sm_pairing_requested = 0; 1300 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1301 #endif 1302 break; 1303 } 1304 break; 1305 default: 1306 break; 1307 } 1308 1309 switch (event){ 1310 case ADDRESS_RESOLUTION_SUCEEDED: 1311 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1312 break; 1313 case ADDRESS_RESOLUTION_FAILED: 1314 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1315 break; 1316 } 1317 } 1318 1319 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1320 1321 int le_db_index = -1; 1322 1323 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1324 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1325 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1326 & SM_AUTHREQ_BONDING ) != 0; 1327 1328 if (bonding_enabed){ 1329 1330 // lookup device based on IRK 1331 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1332 int i; 1333 for (i=0; i < le_device_db_max_count(); i++){ 1334 sm_key_t irk; 1335 bd_addr_t address; 1336 int address_type; 1337 le_device_db_info(i, &address_type, address, irk); 1338 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1339 log_info("sm: device found for IRK, updating"); 1340 le_db_index = i; 1341 break; 1342 } 1343 } 1344 } 1345 1346 // if not found, lookup via public address if possible 1347 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1348 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1349 int i; 1350 for (i=0; i < le_device_db_max_count(); i++){ 1351 bd_addr_t address; 1352 int address_type; 1353 le_device_db_info(i, &address_type, address, NULL); 1354 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1355 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1356 log_info("sm: device found for public address, updating"); 1357 le_db_index = i; 1358 break; 1359 } 1360 } 1361 } 1362 1363 // if not found, add to db 1364 if (le_db_index < 0) { 1365 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1366 } 1367 1368 if (le_db_index >= 0){ 1369 1370 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1371 1372 #ifdef ENABLE_LE_SIGNED_WRITE 1373 // store local CSRK 1374 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1375 log_info("sm: store local CSRK"); 1376 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1377 le_device_db_local_counter_set(le_db_index, 0); 1378 } 1379 1380 // store remote CSRK 1381 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1382 log_info("sm: store remote CSRK"); 1383 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1384 le_device_db_remote_counter_set(le_db_index, 0); 1385 } 1386 #endif 1387 // store encryption information for secure connections: LTK generated by ECDH 1388 if (setup->sm_use_secure_connections){ 1389 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1390 uint8_t zero_rand[8]; 1391 memset(zero_rand, 0, 8); 1392 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1393 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1394 } 1395 1396 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1397 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1398 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1399 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1400 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1401 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1402 1403 } 1404 } 1405 } else { 1406 log_info("Ignoring received keys, bonding not enabled"); 1407 } 1408 1409 // keep le_db_index 1410 sm_conn->sm_le_db_index = le_db_index; 1411 } 1412 1413 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1414 setup->sm_pairing_failed_reason = reason; 1415 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1416 } 1417 1418 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1419 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1420 } 1421 1422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1423 1424 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1425 static int sm_passkey_used(stk_generation_method_t method); 1426 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1427 1428 static void sm_log_ec_keypair(void){ 1429 log_info("Elliptic curve: X"); 1430 log_info_hexdump(&ec_q[0],32); 1431 log_info("Elliptic curve: Y"); 1432 log_info_hexdump(&ec_q[32],32); 1433 } 1434 1435 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1436 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1437 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1438 } else { 1439 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1440 } 1441 } 1442 1443 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1444 if (IS_RESPONDER(sm_conn->sm_role)){ 1445 // Responder 1446 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1447 } else { 1448 // Initiator role 1449 switch (setup->sm_stk_generation_method){ 1450 case JUST_WORKS: 1451 sm_sc_prepare_dhkey_check(sm_conn); 1452 break; 1453 1454 case NK_BOTH_INPUT: 1455 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1456 break; 1457 case PK_INIT_INPUT: 1458 case PK_RESP_INPUT: 1459 case OK_BOTH_INPUT: 1460 if (setup->sm_passkey_bit < 20) { 1461 sm_sc_start_calculating_local_confirm(sm_conn); 1462 } else { 1463 sm_sc_prepare_dhkey_check(sm_conn); 1464 } 1465 break; 1466 case OOB: 1467 // TODO: implement SC OOB 1468 break; 1469 } 1470 } 1471 } 1472 1473 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1474 return sm_cmac_sc_buffer[offset]; 1475 } 1476 1477 static void sm_sc_cmac_done(uint8_t * hash){ 1478 log_info("sm_sc_cmac_done: "); 1479 log_info_hexdump(hash, 16); 1480 1481 sm_connection_t * sm_conn = sm_cmac_connection; 1482 sm_cmac_connection = NULL; 1483 #ifdef ENABLE_CLASSIC 1484 link_key_type_t link_key_type; 1485 #endif 1486 1487 switch (sm_conn->sm_engine_state){ 1488 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1489 memcpy(setup->sm_local_confirm, hash, 16); 1490 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1491 break; 1492 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1493 // check 1494 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1495 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1496 break; 1497 } 1498 sm_sc_state_after_receiving_random(sm_conn); 1499 break; 1500 case SM_SC_W4_CALCULATE_G2: { 1501 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1502 big_endian_store_32(setup->sm_tk, 12, vab); 1503 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1504 sm_trigger_user_response(sm_conn); 1505 break; 1506 } 1507 case SM_SC_W4_CALCULATE_F5_SALT: 1508 memcpy(setup->sm_t, hash, 16); 1509 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1510 break; 1511 case SM_SC_W4_CALCULATE_F5_MACKEY: 1512 memcpy(setup->sm_mackey, hash, 16); 1513 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1514 break; 1515 case SM_SC_W4_CALCULATE_F5_LTK: 1516 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1517 // Errata Service Release to the Bluetooth Specification: ESR09 1518 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1519 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1520 memcpy(setup->sm_ltk, hash, 16); 1521 memcpy(setup->sm_local_ltk, hash, 16); 1522 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1523 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1524 break; 1525 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1526 memcpy(setup->sm_local_dhkey_check, hash, 16); 1527 if (IS_RESPONDER(sm_conn->sm_role)){ 1528 // responder 1529 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1530 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1531 } else { 1532 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1533 } 1534 } else { 1535 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1536 } 1537 break; 1538 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1539 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1540 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1541 break; 1542 } 1543 if (IS_RESPONDER(sm_conn->sm_role)){ 1544 // responder 1545 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1546 } else { 1547 // initiator 1548 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1549 } 1550 break; 1551 case SM_SC_W4_CALCULATE_H6_ILK: 1552 memcpy(setup->sm_t, hash, 16); 1553 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1554 break; 1555 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1556 #ifdef ENABLE_CLASSIC 1557 reverse_128(hash, setup->sm_t); 1558 link_key_type = sm_conn->sm_connection_authenticated ? 1559 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1560 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1561 if (IS_RESPONDER(sm_conn->sm_role)){ 1562 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1563 } else { 1564 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1565 } 1566 #endif 1567 if (IS_RESPONDER(sm_conn->sm_role)){ 1568 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1569 } else { 1570 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1571 } 1572 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1573 sm_done_for_handle(sm_conn->sm_handle); 1574 break; 1575 default: 1576 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1577 break; 1578 } 1579 sm_run(); 1580 } 1581 1582 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){ 1583 const uint16_t message_len = 65; 1584 sm_cmac_connection = sm_conn; 1585 memcpy(sm_cmac_sc_buffer, u, 32); 1586 memcpy(sm_cmac_sc_buffer+32, v, 32); 1587 sm_cmac_sc_buffer[64] = z; 1588 log_info("f4 key"); 1589 log_info_hexdump(x, 16); 1590 log_info("f4 message"); 1591 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1592 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1593 } 1594 1595 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1596 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1597 static const uint8_t f5_length[] = { 0x01, 0x00}; 1598 1599 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1600 1601 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1602 memset(dhkey, 0, 32); 1603 1604 #ifdef USE_MICRO_ECC_FOR_ECDH 1605 #if uECC_SUPPORTS_secp256r1 1606 // standard version 1607 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1()); 1608 #else 1609 // static version 1610 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1611 #endif 1612 #endif 1613 1614 #ifdef USE_MBEDTLS_FOR_ECDH 1615 // da * Pb 1616 mbedtls_mpi d; 1617 mbedtls_ecp_point Q; 1618 mbedtls_ecp_point DH; 1619 mbedtls_mpi_init(&d); 1620 mbedtls_ecp_point_init(&Q); 1621 mbedtls_ecp_point_init(&DH); 1622 mbedtls_mpi_read_binary(&d, ec_d, 32); 1623 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); 1624 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 1625 mbedtls_mpi_lset(&Q.Z, 1); 1626 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1627 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1628 mbedtls_ecp_point_free(&DH); 1629 mbedtls_mpi_free(&d); 1630 mbedtls_ecp_point_free(&Q); 1631 #endif 1632 1633 log_info("dhkey"); 1634 log_info_hexdump(dhkey, 32); 1635 } 1636 #endif 1637 1638 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1639 // calculate salt for f5 1640 const uint16_t message_len = 32; 1641 sm_cmac_connection = sm_conn; 1642 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1643 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1644 } 1645 1646 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){ 1647 const uint16_t message_len = 53; 1648 sm_cmac_connection = sm_conn; 1649 1650 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1651 sm_cmac_sc_buffer[0] = 0; 1652 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1653 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1654 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1655 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1656 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1657 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1658 log_info("f5 key"); 1659 log_info_hexdump(t, 16); 1660 log_info("f5 message for MacKey"); 1661 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1662 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1663 } 1664 1665 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1666 sm_key56_t bd_addr_master, bd_addr_slave; 1667 bd_addr_master[0] = setup->sm_m_addr_type; 1668 bd_addr_slave[0] = setup->sm_s_addr_type; 1669 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1670 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1671 if (IS_RESPONDER(sm_conn->sm_role)){ 1672 // responder 1673 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1674 } else { 1675 // initiator 1676 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1677 } 1678 } 1679 1680 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1681 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1682 const uint16_t message_len = 53; 1683 sm_cmac_connection = sm_conn; 1684 sm_cmac_sc_buffer[0] = 1; 1685 // 1..52 setup before 1686 log_info("f5 key"); 1687 log_info_hexdump(t, 16); 1688 log_info("f5 message for LTK"); 1689 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1690 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1691 } 1692 1693 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1694 f5_ltk(sm_conn, setup->sm_t); 1695 } 1696 1697 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, 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){ 1698 const uint16_t message_len = 65; 1699 sm_cmac_connection = sm_conn; 1700 memcpy(sm_cmac_sc_buffer, n1, 16); 1701 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1702 memcpy(sm_cmac_sc_buffer+32, r, 16); 1703 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1704 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1705 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1706 log_info("f6 key"); 1707 log_info_hexdump(w, 16); 1708 log_info("f6 message"); 1709 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1710 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1711 } 1712 1713 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1714 // - U is 256 bits 1715 // - V is 256 bits 1716 // - X is 128 bits 1717 // - Y is 128 bits 1718 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){ 1719 const uint16_t message_len = 80; 1720 sm_cmac_connection = sm_conn; 1721 memcpy(sm_cmac_sc_buffer, u, 32); 1722 memcpy(sm_cmac_sc_buffer+32, v, 32); 1723 memcpy(sm_cmac_sc_buffer+64, y, 16); 1724 log_info("g2 key"); 1725 log_info_hexdump(x, 16); 1726 log_info("g2 message"); 1727 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1728 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1729 } 1730 1731 static void g2_calculate(sm_connection_t * sm_conn) { 1732 // calc Va if numeric comparison 1733 if (IS_RESPONDER(sm_conn->sm_role)){ 1734 // responder 1735 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1736 } else { 1737 // initiator 1738 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1739 } 1740 } 1741 1742 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1743 uint8_t z = 0; 1744 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1745 // some form of passkey 1746 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1747 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1748 setup->sm_passkey_bit++; 1749 } 1750 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1751 } 1752 1753 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1754 uint8_t z = 0; 1755 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1756 // some form of passkey 1757 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1758 // sm_passkey_bit was increased before sending confirm value 1759 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1760 } 1761 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1762 } 1763 1764 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1765 1766 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1767 // calculate DHKEY 1768 sm_sc_calculate_dhkey(setup->sm_dhkey); 1769 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1770 #endif 1771 1772 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1773 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1774 return; 1775 } else { 1776 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1777 } 1778 1779 } 1780 1781 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1782 // calculate DHKCheck 1783 sm_key56_t bd_addr_master, bd_addr_slave; 1784 bd_addr_master[0] = setup->sm_m_addr_type; 1785 bd_addr_slave[0] = setup->sm_s_addr_type; 1786 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1787 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1788 uint8_t iocap_a[3]; 1789 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1790 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1791 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1792 uint8_t iocap_b[3]; 1793 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1794 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1795 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1796 if (IS_RESPONDER(sm_conn->sm_role)){ 1797 // responder 1798 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1799 } else { 1800 // initiator 1801 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1802 } 1803 } 1804 1805 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1806 // validate E = f6() 1807 sm_key56_t bd_addr_master, bd_addr_slave; 1808 bd_addr_master[0] = setup->sm_m_addr_type; 1809 bd_addr_slave[0] = setup->sm_s_addr_type; 1810 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1811 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1812 1813 uint8_t iocap_a[3]; 1814 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1815 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1816 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1817 uint8_t iocap_b[3]; 1818 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1819 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1820 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1821 if (IS_RESPONDER(sm_conn->sm_role)){ 1822 // responder 1823 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1824 } else { 1825 // initiator 1826 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1827 } 1828 } 1829 1830 1831 // 1832 // Link Key Conversion Function h6 1833 // 1834 // h6(W, keyID) = AES-CMACW(keyID) 1835 // - W is 128 bits 1836 // - keyID is 32 bits 1837 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1838 const uint16_t message_len = 4; 1839 sm_cmac_connection = sm_conn; 1840 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1841 log_info("h6 key"); 1842 log_info_hexdump(w, 16); 1843 log_info("h6 message"); 1844 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1845 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1846 } 1847 1848 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1849 // Errata Service Release to the Bluetooth Specification: ESR09 1850 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1851 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1852 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1853 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1854 } 1855 1856 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1857 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1858 } 1859 1860 #endif 1861 1862 // key management legacy connections: 1863 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1864 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1865 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1866 // - responder reconnects: responder uses LTK receveived from master 1867 1868 // key management secure connections: 1869 // - both devices store same LTK from ECDH key exchange. 1870 1871 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1872 static void sm_load_security_info(sm_connection_t * sm_connection){ 1873 int encryption_key_size; 1874 int authenticated; 1875 int authorized; 1876 1877 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1878 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1879 &encryption_key_size, &authenticated, &authorized); 1880 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1881 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1882 sm_connection->sm_connection_authenticated = authenticated; 1883 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1884 } 1885 #endif 1886 1887 #ifdef ENABLE_LE_PERIPHERAL 1888 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1889 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1890 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1891 // re-establish used key encryption size 1892 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1893 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1894 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1895 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1896 log_info("sm: received ltk request with key size %u, authenticated %u", 1897 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1898 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1899 } 1900 #endif 1901 1902 static void sm_run(void){ 1903 1904 btstack_linked_list_iterator_t it; 1905 1906 // assert that stack has already bootet 1907 if (hci_get_state() != HCI_STATE_WORKING) return; 1908 1909 // assert that we can send at least commands 1910 if (!hci_can_send_command_packet_now()) return; 1911 1912 // 1913 // non-connection related behaviour 1914 // 1915 1916 // distributed key generation 1917 switch (dkg_state){ 1918 case DKG_CALC_IRK: 1919 // already busy? 1920 if (sm_aes128_state == SM_AES128_IDLE) { 1921 // IRK = d1(IR, 1, 0) 1922 sm_key_t d1_prime; 1923 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1924 dkg_next_state(); 1925 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1926 return; 1927 } 1928 break; 1929 case DKG_CALC_DHK: 1930 // already busy? 1931 if (sm_aes128_state == SM_AES128_IDLE) { 1932 // DHK = d1(IR, 3, 0) 1933 sm_key_t d1_prime; 1934 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1935 dkg_next_state(); 1936 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1937 return; 1938 } 1939 break; 1940 default: 1941 break; 1942 } 1943 1944 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1945 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1946 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1947 sm_random_start(NULL); 1948 #else 1949 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1950 hci_send_cmd(&hci_le_read_local_p256_public_key); 1951 #endif 1952 return; 1953 } 1954 #endif 1955 1956 // random address updates 1957 switch (rau_state){ 1958 case RAU_GET_RANDOM: 1959 rau_next_state(); 1960 sm_random_start(NULL); 1961 return; 1962 case RAU_GET_ENC: 1963 // already busy? 1964 if (sm_aes128_state == SM_AES128_IDLE) { 1965 sm_key_t r_prime; 1966 sm_ah_r_prime(sm_random_address, r_prime); 1967 rau_next_state(); 1968 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1969 return; 1970 } 1971 break; 1972 case RAU_SET_ADDRESS: 1973 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1974 rau_state = RAU_IDLE; 1975 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1976 return; 1977 default: 1978 break; 1979 } 1980 1981 #ifdef ENABLE_CMAC_ENGINE 1982 // CMAC 1983 switch (sm_cmac_state){ 1984 case CMAC_CALC_SUBKEYS: 1985 case CMAC_CALC_MI: 1986 case CMAC_CALC_MLAST: 1987 // already busy? 1988 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1989 sm_cmac_handle_aes_engine_ready(); 1990 return; 1991 default: 1992 break; 1993 } 1994 #endif 1995 1996 // CSRK Lookup 1997 // -- if csrk lookup ready, find connection that require csrk lookup 1998 if (sm_address_resolution_idle()){ 1999 hci_connections_get_iterator(&it); 2000 while(btstack_linked_list_iterator_has_next(&it)){ 2001 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2002 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2003 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2004 // and start lookup 2005 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); 2006 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2007 break; 2008 } 2009 } 2010 } 2011 2012 // -- if csrk lookup ready, resolved addresses for received addresses 2013 if (sm_address_resolution_idle()) { 2014 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2015 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2016 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2017 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2018 btstack_memory_sm_lookup_entry_free(entry); 2019 } 2020 } 2021 2022 // -- Continue with CSRK device lookup by public or resolvable private address 2023 if (!sm_address_resolution_idle()){ 2024 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2025 while (sm_address_resolution_test < le_device_db_max_count()){ 2026 int addr_type; 2027 bd_addr_t addr; 2028 sm_key_t irk; 2029 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2030 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2031 2032 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 2033 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2034 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2035 break; 2036 } 2037 2038 if (sm_address_resolution_addr_type == 0){ 2039 sm_address_resolution_test++; 2040 continue; 2041 } 2042 2043 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2044 2045 log_info("LE Device Lookup: calculate AH"); 2046 log_info_key("IRK", irk); 2047 2048 sm_key_t r_prime; 2049 sm_ah_r_prime(sm_address_resolution_address, r_prime); 2050 sm_address_resolution_ah_calculation_active = 1; 2051 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 2052 return; 2053 } 2054 2055 if (sm_address_resolution_test >= le_device_db_max_count()){ 2056 log_info("LE Device Lookup: not found"); 2057 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2058 } 2059 } 2060 2061 // handle basic actions that don't requires the full context 2062 hci_connections_get_iterator(&it); 2063 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2064 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2065 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2066 switch(sm_connection->sm_engine_state){ 2067 // responder side 2068 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2069 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2070 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2071 return; 2072 2073 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2074 case SM_SC_RECEIVED_LTK_REQUEST: 2075 switch (sm_connection->sm_irk_lookup_state){ 2076 case IRK_LOOKUP_FAILED: 2077 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2078 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2079 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2080 return; 2081 default: 2082 break; 2083 } 2084 break; 2085 #endif 2086 default: 2087 break; 2088 } 2089 } 2090 2091 // 2092 // active connection handling 2093 // -- use loop to handle next connection if lock on setup context is released 2094 2095 while (1) { 2096 2097 // Find connections that requires setup context and make active if no other is locked 2098 hci_connections_get_iterator(&it); 2099 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2100 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2101 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2102 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2103 int done = 1; 2104 int err; 2105 UNUSED(err); 2106 switch (sm_connection->sm_engine_state) { 2107 #ifdef ENABLE_LE_PERIPHERAL 2108 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2109 // send packet if possible, 2110 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2111 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2112 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2113 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2114 } else { 2115 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2116 } 2117 // don't lock sxetup context yet 2118 done = 0; 2119 break; 2120 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2121 sm_reset_setup(); 2122 sm_init_setup(sm_connection); 2123 // recover pairing request 2124 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2125 err = sm_stk_generation_init(sm_connection); 2126 2127 #ifdef ENABLE_TESTING_SUPPORT 2128 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2129 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2130 err = test_pairing_failure; 2131 } 2132 #endif 2133 if (err){ 2134 setup->sm_pairing_failed_reason = err; 2135 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2136 break; 2137 } 2138 sm_timeout_start(sm_connection); 2139 // generate random number first, if we need to show passkey 2140 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2141 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2142 break; 2143 } 2144 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2145 break; 2146 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2147 sm_reset_setup(); 2148 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2149 break; 2150 #endif 2151 #ifdef ENABLE_LE_CENTRAL 2152 case SM_INITIATOR_PH0_HAS_LTK: 2153 sm_reset_setup(); 2154 sm_load_security_info(sm_connection); 2155 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2156 break; 2157 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2158 sm_reset_setup(); 2159 sm_init_setup(sm_connection); 2160 sm_timeout_start(sm_connection); 2161 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2162 break; 2163 #endif 2164 2165 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2166 case SM_SC_RECEIVED_LTK_REQUEST: 2167 switch (sm_connection->sm_irk_lookup_state){ 2168 case IRK_LOOKUP_SUCCEEDED: 2169 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2170 // start using context by loading security info 2171 sm_reset_setup(); 2172 sm_load_security_info(sm_connection); 2173 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2174 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2175 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2176 break; 2177 } 2178 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2179 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2180 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2181 // don't lock setup context yet 2182 return; 2183 default: 2184 // just wait until IRK lookup is completed 2185 // don't lock setup context yet 2186 done = 0; 2187 break; 2188 } 2189 break; 2190 #endif 2191 default: 2192 done = 0; 2193 break; 2194 } 2195 if (done){ 2196 sm_active_connection_handle = sm_connection->sm_handle; 2197 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); 2198 } 2199 } 2200 2201 // 2202 // active connection handling 2203 // 2204 2205 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2206 2207 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2208 if (!connection) { 2209 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2210 return; 2211 } 2212 2213 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2214 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_NEEDED){ 2215 setup->sm_state_vars &= ~SM_STATE_VAR_DHKEY_NEEDED; 2216 hci_send_cmd(&hci_le_generate_dhkey, &setup->sm_peer_q[0], &setup->sm_peer_q[32]); 2217 return; 2218 } 2219 #endif 2220 2221 // assert that we could send a SM PDU - not needed for all of the following 2222 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2223 log_info("cannot send now, requesting can send now event"); 2224 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2225 return; 2226 } 2227 2228 // send keypress notifications 2229 if (setup->sm_keypress_notification){ 2230 int i; 2231 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2232 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2233 uint8_t action = 0; 2234 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2235 if (flags & (1<<i)){ 2236 int clear_flag = 1; 2237 switch (i){ 2238 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2239 case SM_KEYPRESS_PASSKEY_CLEARED: 2240 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2241 default: 2242 break; 2243 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2244 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2245 num_actions--; 2246 clear_flag = num_actions == 0; 2247 break; 2248 } 2249 if (clear_flag){ 2250 flags &= ~(1<<i); 2251 } 2252 action = i; 2253 break; 2254 } 2255 } 2256 setup->sm_keypress_notification = (num_actions << 5) | flags; 2257 2258 // send keypress notification 2259 uint8_t buffer[2]; 2260 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2261 buffer[1] = action; 2262 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2263 2264 // try 2265 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2266 return; 2267 } 2268 2269 sm_key_t plaintext; 2270 int key_distribution_flags; 2271 UNUSED(key_distribution_flags); 2272 2273 log_info("sm_run: state %u", connection->sm_engine_state); 2274 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2275 log_info("sm_run // cannot send"); 2276 } 2277 switch (connection->sm_engine_state){ 2278 2279 // general 2280 case SM_GENERAL_SEND_PAIRING_FAILED: { 2281 uint8_t buffer[2]; 2282 buffer[0] = SM_CODE_PAIRING_FAILED; 2283 buffer[1] = setup->sm_pairing_failed_reason; 2284 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2285 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2286 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2287 sm_done_for_handle(connection->sm_handle); 2288 break; 2289 } 2290 2291 // responding state 2292 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2293 case SM_SC_W2_GET_RANDOM_A: 2294 sm_random_start(connection); 2295 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2296 break; 2297 case SM_SC_W2_GET_RANDOM_B: 2298 sm_random_start(connection); 2299 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2300 break; 2301 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2302 if (!sm_cmac_ready()) break; 2303 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2304 sm_sc_calculate_local_confirm(connection); 2305 break; 2306 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2307 if (!sm_cmac_ready()) break; 2308 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2309 sm_sc_calculate_remote_confirm(connection); 2310 break; 2311 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2312 if (!sm_cmac_ready()) break; 2313 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2314 sm_sc_calculate_f6_for_dhkey_check(connection); 2315 break; 2316 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2317 if (!sm_cmac_ready()) break; 2318 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2319 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2320 break; 2321 case SM_SC_W2_CALCULATE_F5_SALT: 2322 if (!sm_cmac_ready()) break; 2323 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2324 f5_calculate_salt(connection); 2325 break; 2326 case SM_SC_W2_CALCULATE_F5_MACKEY: 2327 if (!sm_cmac_ready()) break; 2328 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2329 f5_calculate_mackey(connection); 2330 break; 2331 case SM_SC_W2_CALCULATE_F5_LTK: 2332 if (!sm_cmac_ready()) break; 2333 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2334 f5_calculate_ltk(connection); 2335 break; 2336 case SM_SC_W2_CALCULATE_G2: 2337 if (!sm_cmac_ready()) break; 2338 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2339 g2_calculate(connection); 2340 break; 2341 case SM_SC_W2_CALCULATE_H6_ILK: 2342 if (!sm_cmac_ready()) break; 2343 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2344 h6_calculate_ilk(connection); 2345 break; 2346 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2347 if (!sm_cmac_ready()) break; 2348 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2349 h6_calculate_br_edr_link_key(connection); 2350 break; 2351 #endif 2352 2353 #ifdef ENABLE_LE_CENTRAL 2354 // initiator side 2355 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2356 sm_key_t peer_ltk_flipped; 2357 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2358 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2359 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2360 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2361 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2362 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2363 return; 2364 } 2365 2366 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2367 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2368 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2369 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2370 sm_timeout_reset(connection); 2371 break; 2372 #endif 2373 2374 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2375 2376 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2377 int trigger_user_response = 0; 2378 2379 uint8_t buffer[65]; 2380 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2381 // 2382 reverse_256(&ec_q[0], &buffer[1]); 2383 reverse_256(&ec_q[32], &buffer[33]); 2384 2385 // stk generation method 2386 // passkey entry: notify app to show passkey or to request passkey 2387 switch (setup->sm_stk_generation_method){ 2388 case JUST_WORKS: 2389 case NK_BOTH_INPUT: 2390 if (IS_RESPONDER(connection->sm_role)){ 2391 // responder 2392 sm_sc_start_calculating_local_confirm(connection); 2393 } else { 2394 // initiator 2395 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2396 } 2397 break; 2398 case PK_INIT_INPUT: 2399 case PK_RESP_INPUT: 2400 case OK_BOTH_INPUT: 2401 // use random TK for display 2402 memcpy(setup->sm_ra, setup->sm_tk, 16); 2403 memcpy(setup->sm_rb, setup->sm_tk, 16); 2404 setup->sm_passkey_bit = 0; 2405 2406 if (IS_RESPONDER(connection->sm_role)){ 2407 // responder 2408 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2409 } else { 2410 // initiator 2411 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2412 } 2413 trigger_user_response = 1; 2414 break; 2415 case OOB: 2416 // TODO: implement SC OOB 2417 break; 2418 } 2419 2420 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2421 sm_timeout_reset(connection); 2422 2423 // trigger user response after sending pdu 2424 if (trigger_user_response){ 2425 sm_trigger_user_response(connection); 2426 } 2427 break; 2428 } 2429 case SM_SC_SEND_CONFIRMATION: { 2430 uint8_t buffer[17]; 2431 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2432 reverse_128(setup->sm_local_confirm, &buffer[1]); 2433 if (IS_RESPONDER(connection->sm_role)){ 2434 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2435 } else { 2436 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2437 } 2438 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2439 sm_timeout_reset(connection); 2440 break; 2441 } 2442 case SM_SC_SEND_PAIRING_RANDOM: { 2443 uint8_t buffer[17]; 2444 buffer[0] = SM_CODE_PAIRING_RANDOM; 2445 reverse_128(setup->sm_local_nonce, &buffer[1]); 2446 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2447 if (IS_RESPONDER(connection->sm_role)){ 2448 // responder 2449 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2450 } else { 2451 // initiator 2452 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2453 } 2454 } else { 2455 if (IS_RESPONDER(connection->sm_role)){ 2456 // responder 2457 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2458 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2459 } else { 2460 sm_sc_prepare_dhkey_check(connection); 2461 } 2462 } else { 2463 // initiator 2464 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2465 } 2466 } 2467 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2468 sm_timeout_reset(connection); 2469 break; 2470 } 2471 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2472 uint8_t buffer[17]; 2473 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2474 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2475 2476 if (IS_RESPONDER(connection->sm_role)){ 2477 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2478 } else { 2479 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2480 } 2481 2482 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2483 sm_timeout_reset(connection); 2484 break; 2485 } 2486 2487 #endif 2488 2489 #ifdef ENABLE_LE_PERIPHERAL 2490 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2491 // echo initiator for now 2492 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2493 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2494 2495 if (setup->sm_use_secure_connections){ 2496 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2497 // skip LTK/EDIV for SC 2498 log_info("sm: dropping encryption information flag"); 2499 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2500 } else { 2501 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2502 } 2503 2504 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); 2505 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); 2506 // update key distribution after ENC was dropped 2507 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2508 2509 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2510 sm_timeout_reset(connection); 2511 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2512 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2513 sm_trigger_user_response(connection); 2514 } 2515 return; 2516 #endif 2517 2518 case SM_PH2_SEND_PAIRING_RANDOM: { 2519 uint8_t buffer[17]; 2520 buffer[0] = SM_CODE_PAIRING_RANDOM; 2521 reverse_128(setup->sm_local_random, &buffer[1]); 2522 if (IS_RESPONDER(connection->sm_role)){ 2523 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2524 } else { 2525 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2526 } 2527 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2528 sm_timeout_reset(connection); 2529 break; 2530 } 2531 2532 case SM_PH2_GET_RANDOM_TK: 2533 case SM_PH2_C1_GET_RANDOM_A: 2534 case SM_PH2_C1_GET_RANDOM_B: 2535 case SM_PH3_GET_RANDOM: 2536 case SM_PH3_GET_DIV: 2537 sm_next_responding_state(connection); 2538 sm_random_start(connection); 2539 return; 2540 2541 case SM_PH2_C1_GET_ENC_B: 2542 case SM_PH2_C1_GET_ENC_D: 2543 // already busy? 2544 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2545 sm_next_responding_state(connection); 2546 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2547 return; 2548 2549 case SM_PH3_LTK_GET_ENC: 2550 case SM_RESPONDER_PH4_LTK_GET_ENC: 2551 // already busy? 2552 if (sm_aes128_state == SM_AES128_IDLE) { 2553 sm_key_t d_prime; 2554 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2555 sm_next_responding_state(connection); 2556 sm_aes128_start(sm_persistent_er, d_prime, connection); 2557 return; 2558 } 2559 break; 2560 2561 case SM_PH3_CSRK_GET_ENC: 2562 // already busy? 2563 if (sm_aes128_state == SM_AES128_IDLE) { 2564 sm_key_t d_prime; 2565 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2566 sm_next_responding_state(connection); 2567 sm_aes128_start(sm_persistent_er, d_prime, connection); 2568 return; 2569 } 2570 break; 2571 2572 case SM_PH2_C1_GET_ENC_C: 2573 // already busy? 2574 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2575 // calculate m_confirm using aes128 engine - step 1 2576 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, plaintext); 2577 sm_next_responding_state(connection); 2578 sm_aes128_start(setup->sm_tk, plaintext, connection); 2579 break; 2580 case SM_PH2_C1_GET_ENC_A: 2581 // already busy? 2582 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2583 // calculate confirm using aes128 engine - step 1 2584 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, plaintext); 2585 sm_next_responding_state(connection); 2586 sm_aes128_start(setup->sm_tk, plaintext, connection); 2587 break; 2588 case SM_PH2_CALC_STK: 2589 // already busy? 2590 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2591 // calculate STK 2592 if (IS_RESPONDER(connection->sm_role)){ 2593 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2594 } else { 2595 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2596 } 2597 sm_next_responding_state(connection); 2598 sm_aes128_start(setup->sm_tk, plaintext, connection); 2599 break; 2600 case SM_PH3_Y_GET_ENC: 2601 // already busy? 2602 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2603 // PH3B2 - calculate Y from - enc 2604 // Y = dm(DHK, Rand) 2605 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2606 sm_next_responding_state(connection); 2607 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2608 return; 2609 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2610 uint8_t buffer[17]; 2611 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2612 reverse_128(setup->sm_local_confirm, &buffer[1]); 2613 if (IS_RESPONDER(connection->sm_role)){ 2614 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2615 } else { 2616 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2617 } 2618 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2619 sm_timeout_reset(connection); 2620 return; 2621 } 2622 #ifdef ENABLE_LE_PERIPHERAL 2623 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2624 sm_key_t stk_flipped; 2625 reverse_128(setup->sm_ltk, stk_flipped); 2626 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2627 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2628 return; 2629 } 2630 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2631 sm_key_t ltk_flipped; 2632 reverse_128(setup->sm_ltk, ltk_flipped); 2633 connection->sm_engine_state = SM_RESPONDER_IDLE; 2634 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2635 sm_done_for_handle(connection->sm_handle); 2636 return; 2637 } 2638 case SM_RESPONDER_PH4_Y_GET_ENC: 2639 // already busy? 2640 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2641 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2642 // Y = dm(DHK, Rand) 2643 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2644 sm_next_responding_state(connection); 2645 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2646 return; 2647 #endif 2648 #ifdef ENABLE_LE_CENTRAL 2649 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2650 sm_key_t stk_flipped; 2651 reverse_128(setup->sm_ltk, stk_flipped); 2652 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2653 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2654 return; 2655 } 2656 #endif 2657 2658 case SM_PH3_DISTRIBUTE_KEYS: 2659 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2660 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2661 uint8_t buffer[17]; 2662 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2663 reverse_128(setup->sm_ltk, &buffer[1]); 2664 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2665 sm_timeout_reset(connection); 2666 return; 2667 } 2668 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2669 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2670 uint8_t buffer[11]; 2671 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2672 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2673 reverse_64(setup->sm_local_rand, &buffer[3]); 2674 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2675 sm_timeout_reset(connection); 2676 return; 2677 } 2678 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2679 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2680 uint8_t buffer[17]; 2681 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2682 reverse_128(sm_persistent_irk, &buffer[1]); 2683 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2684 sm_timeout_reset(connection); 2685 return; 2686 } 2687 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2688 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2689 bd_addr_t local_address; 2690 uint8_t buffer[8]; 2691 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2692 switch (gap_random_address_get_mode()){ 2693 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2694 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2695 // public or static random 2696 gap_le_get_own_address(&buffer[1], local_address); 2697 break; 2698 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2699 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2700 // fallback to public 2701 gap_local_bd_addr(local_address); 2702 buffer[1] = 0; 2703 break; 2704 } 2705 reverse_bd_addr(local_address, &buffer[2]); 2706 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2707 sm_timeout_reset(connection); 2708 return; 2709 } 2710 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2711 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2712 2713 // hack to reproduce test runs 2714 if (test_use_fixed_local_csrk){ 2715 memset(setup->sm_local_csrk, 0xcc, 16); 2716 } 2717 2718 uint8_t buffer[17]; 2719 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2720 reverse_128(setup->sm_local_csrk, &buffer[1]); 2721 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2722 sm_timeout_reset(connection); 2723 return; 2724 } 2725 2726 // keys are sent 2727 if (IS_RESPONDER(connection->sm_role)){ 2728 // slave -> receive master keys if any 2729 if (sm_key_distribution_all_received(connection)){ 2730 sm_key_distribution_handle_all_received(connection); 2731 connection->sm_engine_state = SM_RESPONDER_IDLE; 2732 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2733 sm_done_for_handle(connection->sm_handle); 2734 } else { 2735 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2736 } 2737 } else { 2738 // master -> all done 2739 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2740 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2741 sm_done_for_handle(connection->sm_handle); 2742 } 2743 break; 2744 2745 default: 2746 break; 2747 } 2748 2749 // check again if active connection was released 2750 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2751 } 2752 } 2753 2754 // note: aes engine is ready as we just got the aes result 2755 static void sm_handle_encryption_result(uint8_t * data){ 2756 2757 sm_aes128_state = SM_AES128_IDLE; 2758 2759 if (sm_address_resolution_ah_calculation_active){ 2760 sm_address_resolution_ah_calculation_active = 0; 2761 // compare calulated address against connecting device 2762 uint8_t hash[3]; 2763 reverse_24(data, hash); 2764 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2765 log_info("LE Device Lookup: matched resolvable private address"); 2766 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2767 return; 2768 } 2769 // no match, try next 2770 sm_address_resolution_test++; 2771 return; 2772 } 2773 2774 switch (dkg_state){ 2775 case DKG_W4_IRK: 2776 reverse_128(data, sm_persistent_irk); 2777 log_info_key("irk", sm_persistent_irk); 2778 dkg_next_state(); 2779 return; 2780 case DKG_W4_DHK: 2781 reverse_128(data, sm_persistent_dhk); 2782 log_info_key("dhk", sm_persistent_dhk); 2783 dkg_next_state(); 2784 // SM Init Finished 2785 return; 2786 default: 2787 break; 2788 } 2789 2790 switch (rau_state){ 2791 case RAU_W4_ENC: 2792 reverse_24(data, &sm_random_address[3]); 2793 rau_next_state(); 2794 return; 2795 default: 2796 break; 2797 } 2798 2799 #ifdef ENABLE_CMAC_ENGINE 2800 switch (sm_cmac_state){ 2801 case CMAC_W4_SUBKEYS: 2802 case CMAC_W4_MI: 2803 case CMAC_W4_MLAST: 2804 { 2805 sm_key_t t; 2806 reverse_128(data, t); 2807 sm_cmac_handle_encryption_result(t); 2808 } 2809 return; 2810 default: 2811 break; 2812 } 2813 #endif 2814 2815 // retrieve sm_connection provided to sm_aes128_start_encryption 2816 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2817 if (!connection) return; 2818 switch (connection->sm_engine_state){ 2819 case SM_PH2_C1_W4_ENC_A: 2820 case SM_PH2_C1_W4_ENC_C: 2821 { 2822 sm_key_t t2; 2823 reverse_128(data, t2); 2824 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2825 } 2826 sm_next_responding_state(connection); 2827 return; 2828 case SM_PH2_C1_W4_ENC_B: 2829 reverse_128(data, setup->sm_local_confirm); 2830 log_info_key("c1!", setup->sm_local_confirm); 2831 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2832 return; 2833 case SM_PH2_C1_W4_ENC_D: 2834 { 2835 sm_key_t peer_confirm_test; 2836 reverse_128(data, peer_confirm_test); 2837 log_info_key("c1!", peer_confirm_test); 2838 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2839 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2840 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2841 return; 2842 } 2843 if (IS_RESPONDER(connection->sm_role)){ 2844 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2845 } else { 2846 connection->sm_engine_state = SM_PH2_CALC_STK; 2847 } 2848 } 2849 return; 2850 case SM_PH2_W4_STK: 2851 reverse_128(data, setup->sm_ltk); 2852 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2853 log_info_key("stk", setup->sm_ltk); 2854 if (IS_RESPONDER(connection->sm_role)){ 2855 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2856 } else { 2857 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2858 } 2859 return; 2860 case SM_PH3_Y_W4_ENC:{ 2861 sm_key_t y128; 2862 reverse_128(data, y128); 2863 setup->sm_local_y = big_endian_read_16(y128, 14); 2864 log_info_hex16("y", setup->sm_local_y); 2865 // PH3B3 - calculate EDIV 2866 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2867 log_info_hex16("ediv", setup->sm_local_ediv); 2868 // PH3B4 - calculate LTK - enc 2869 // LTK = d1(ER, DIV, 0)) 2870 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2871 return; 2872 } 2873 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2874 sm_key_t y128; 2875 reverse_128(data, y128); 2876 setup->sm_local_y = big_endian_read_16(y128, 14); 2877 log_info_hex16("y", setup->sm_local_y); 2878 2879 // PH3B3 - calculate DIV 2880 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2881 log_info_hex16("ediv", setup->sm_local_ediv); 2882 // PH3B4 - calculate LTK - enc 2883 // LTK = d1(ER, DIV, 0)) 2884 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2885 return; 2886 } 2887 case SM_PH3_LTK_W4_ENC: 2888 reverse_128(data, setup->sm_ltk); 2889 log_info_key("ltk", setup->sm_ltk); 2890 // calc CSRK next 2891 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2892 return; 2893 case SM_PH3_CSRK_W4_ENC: 2894 reverse_128(data, setup->sm_local_csrk); 2895 log_info_key("csrk", setup->sm_local_csrk); 2896 if (setup->sm_key_distribution_send_set){ 2897 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2898 } else { 2899 // no keys to send, just continue 2900 if (IS_RESPONDER(connection->sm_role)){ 2901 // slave -> receive master keys 2902 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2903 } else { 2904 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2905 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2906 } else { 2907 // master -> all done 2908 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2909 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2910 sm_done_for_handle(connection->sm_handle); 2911 } 2912 } 2913 } 2914 return; 2915 #ifdef ENABLE_LE_PERIPHERAL 2916 case SM_RESPONDER_PH4_LTK_W4_ENC: 2917 reverse_128(data, setup->sm_ltk); 2918 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2919 log_info_key("ltk", setup->sm_ltk); 2920 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2921 return; 2922 #endif 2923 default: 2924 break; 2925 } 2926 } 2927 2928 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2929 2930 #if (defined(USE_MICRO_ECC_FOR_ECDH) && !defined(WICED_VERSION)) || defined(USE_MBEDTLS_FOR_ECDH) 2931 // @return OK 2932 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2933 if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; 2934 int offset = setup->sm_passkey_bit; 2935 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2936 while (size) { 2937 *buffer++ = setup->sm_peer_q[offset++]; 2938 size--; 2939 } 2940 setup->sm_passkey_bit = offset; 2941 return 1; 2942 } 2943 #endif 2944 #ifdef USE_MBEDTLS_FOR_ECDH 2945 // @return error - just wrap sm_generate_f_rng 2946 static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ 2947 UNUSED(context); 2948 return sm_generate_f_rng(buffer, size) == 0; 2949 } 2950 #endif /* USE_MBEDTLS_FOR_ECDH */ 2951 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2952 2953 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2954 static void sm_handle_random_result(uint8_t * data){ 2955 2956 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2957 2958 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2959 int num_bytes = setup->sm_passkey_bit; 2960 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 2961 num_bytes += 8; 2962 setup->sm_passkey_bit = num_bytes; 2963 2964 if (num_bytes >= 64){ 2965 2966 // init pre-generated random data from sm_peer_q 2967 setup->sm_passkey_bit = 0; 2968 2969 // generate EC key 2970 #ifdef USE_MICRO_ECC_FOR_ECDH 2971 2972 #ifndef WICED_VERSION 2973 log_info("set uECC RNG for initial key generation with 64 random bytes"); 2974 // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it 2975 uECC_set_rng(&sm_generate_f_rng); 2976 #endif /* WICED_VERSION */ 2977 2978 #if uECC_SUPPORTS_secp256r1 2979 // standard version 2980 uECC_make_key(ec_q, ec_d, uECC_secp256r1()); 2981 2982 // disable RNG again, as returning no randmon data lets shared key generation fail 2983 log_info("disable uECC RNG in standard version after key generation"); 2984 uECC_set_rng(NULL); 2985 #else 2986 // static version 2987 uECC_make_key(ec_q, ec_d); 2988 #endif 2989 #endif /* USE_MICRO_ECC_FOR_ECDH */ 2990 2991 #ifdef USE_MBEDTLS_FOR_ECDH 2992 mbedtls_mpi d; 2993 mbedtls_ecp_point P; 2994 mbedtls_mpi_init(&d); 2995 mbedtls_ecp_point_init(&P); 2996 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); 2997 log_info("gen keypair %x", res); 2998 mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); 2999 mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); 3000 mbedtls_mpi_write_binary(&d, ec_d, 32); 3001 mbedtls_ecp_point_free(&P); 3002 mbedtls_mpi_free(&d); 3003 #endif /* USE_MBEDTLS_FOR_ECDH */ 3004 3005 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3006 log_info("Elliptic curve: d"); 3007 log_info_hexdump(ec_d,32); 3008 sm_log_ec_keypair(); 3009 } 3010 } 3011 #endif 3012 3013 switch (rau_state){ 3014 case RAU_W4_RANDOM: 3015 // non-resolvable vs. resolvable 3016 switch (gap_random_adress_type){ 3017 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3018 // resolvable: use random as prand and calc address hash 3019 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3020 memcpy(sm_random_address, data, 3); 3021 sm_random_address[0] &= 0x3f; 3022 sm_random_address[0] |= 0x40; 3023 rau_state = RAU_GET_ENC; 3024 break; 3025 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3026 default: 3027 // "The two most significant bits of the address shall be equal to ‘0’"" 3028 memcpy(sm_random_address, data, 6); 3029 sm_random_address[0] &= 0x3f; 3030 rau_state = RAU_SET_ADDRESS; 3031 break; 3032 } 3033 return; 3034 default: 3035 break; 3036 } 3037 3038 // retrieve sm_connection provided to sm_random_start 3039 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 3040 if (!connection) return; 3041 switch (connection->sm_engine_state){ 3042 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3043 case SM_SC_W4_GET_RANDOM_A: 3044 memcpy(&setup->sm_local_nonce[0], data, 8); 3045 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 3046 break; 3047 case SM_SC_W4_GET_RANDOM_B: 3048 memcpy(&setup->sm_local_nonce[8], data, 8); 3049 // initiator & jw/nc -> send pairing random 3050 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3051 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3052 break; 3053 } else { 3054 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3055 } 3056 break; 3057 #endif 3058 3059 case SM_PH2_W4_RANDOM_TK: 3060 { 3061 sm_reset_tk(); 3062 uint32_t tk; 3063 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3064 // map random to 0-999999 without speding much cycles on a modulus operation 3065 tk = little_endian_read_32(data,0); 3066 tk = tk & 0xfffff; // 1048575 3067 if (tk >= 999999){ 3068 tk = tk - 999999; 3069 } 3070 } else { 3071 // override with pre-defined passkey 3072 tk = sm_fixed_passkey_in_display_role; 3073 } 3074 big_endian_store_32(setup->sm_tk, 12, tk); 3075 if (IS_RESPONDER(connection->sm_role)){ 3076 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3077 } else { 3078 if (setup->sm_use_secure_connections){ 3079 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3080 } else { 3081 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3082 sm_trigger_user_response(connection); 3083 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3084 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3085 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3086 } 3087 } 3088 } 3089 return; 3090 } 3091 case SM_PH2_C1_W4_RANDOM_A: 3092 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 3093 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 3094 return; 3095 case SM_PH2_C1_W4_RANDOM_B: 3096 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 3097 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3098 return; 3099 case SM_PH3_W4_RANDOM: 3100 reverse_64(data, setup->sm_local_rand); 3101 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3102 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 3103 // no db for authenticated flag hack: store flag in bit 4 of LSB 3104 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 3105 connection->sm_engine_state = SM_PH3_GET_DIV; 3106 return; 3107 case SM_PH3_W4_DIV: 3108 // use 16 bit from random value as div 3109 setup->sm_local_div = big_endian_read_16(data, 0); 3110 log_info_hex16("div", setup->sm_local_div); 3111 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3112 return; 3113 default: 3114 break; 3115 } 3116 } 3117 3118 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3119 3120 UNUSED(channel); // ok: there is no channel 3121 UNUSED(size); // ok: fixed format HCI events 3122 3123 sm_connection_t * sm_conn; 3124 hci_con_handle_t con_handle; 3125 3126 switch (packet_type) { 3127 3128 case HCI_EVENT_PACKET: 3129 switch (hci_event_packet_get_type(packet)) { 3130 3131 case BTSTACK_EVENT_STATE: 3132 // bt stack activated, get started 3133 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3134 log_info("HCI Working!"); 3135 3136 3137 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 3138 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3139 if (!sm_have_ec_keypair){ 3140 setup->sm_passkey_bit = 0; 3141 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3142 } 3143 #endif 3144 // trigger Random Address generation if requested before 3145 switch (gap_random_adress_type){ 3146 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3147 rau_state = RAU_IDLE; 3148 break; 3149 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 3150 rau_state = RAU_SET_ADDRESS; 3151 break; 3152 default: 3153 rau_state = RAU_GET_RANDOM; 3154 break; 3155 } 3156 sm_run(); 3157 } 3158 break; 3159 3160 case HCI_EVENT_LE_META: 3161 switch (packet[2]) { 3162 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3163 3164 log_info("sm: connected"); 3165 3166 if (packet[3]) return; // connection failed 3167 3168 con_handle = little_endian_read_16(packet, 4); 3169 sm_conn = sm_get_connection_for_handle(con_handle); 3170 if (!sm_conn) break; 3171 3172 sm_conn->sm_handle = con_handle; 3173 sm_conn->sm_role = packet[6]; 3174 sm_conn->sm_peer_addr_type = packet[7]; 3175 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3176 3177 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3178 3179 // reset security properties 3180 sm_conn->sm_connection_encrypted = 0; 3181 sm_conn->sm_connection_authenticated = 0; 3182 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3183 sm_conn->sm_le_db_index = -1; 3184 3185 // prepare CSRK lookup (does not involve setup) 3186 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3187 3188 // just connected -> everything else happens in sm_run() 3189 if (IS_RESPONDER(sm_conn->sm_role)){ 3190 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3191 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3192 if (sm_slave_request_security) { 3193 // request security if requested by app 3194 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3195 } else { 3196 // otherwise, wait for pairing request 3197 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3198 } 3199 } 3200 break; 3201 } else { 3202 // master 3203 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3204 } 3205 break; 3206 3207 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3208 con_handle = little_endian_read_16(packet, 3); 3209 sm_conn = sm_get_connection_for_handle(con_handle); 3210 if (!sm_conn) break; 3211 3212 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3213 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3214 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3215 break; 3216 } 3217 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3218 // PH2 SEND LTK as we need to exchange keys in PH3 3219 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3220 break; 3221 } 3222 3223 // store rand and ediv 3224 reverse_64(&packet[5], sm_conn->sm_local_rand); 3225 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3226 3227 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3228 // potentially stored LTK is from the master 3229 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3230 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3231 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3232 break; 3233 } 3234 // additionally check if remote is in LE Device DB if requested 3235 switch(sm_conn->sm_irk_lookup_state){ 3236 case IRK_LOOKUP_FAILED: 3237 log_info("LTK Request: device not in device db"); 3238 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3239 break; 3240 case IRK_LOOKUP_SUCCEEDED: 3241 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3242 break; 3243 default: 3244 // wait for irk look doen 3245 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3246 break; 3247 } 3248 break; 3249 } 3250 3251 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3252 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3253 #else 3254 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3255 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3256 #endif 3257 break; 3258 3259 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3260 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3261 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3262 log_error("Read Local P256 Public Key failed"); 3263 break; 3264 } 3265 3266 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3267 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3268 3269 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3270 sm_log_ec_keypair(); 3271 break; 3272 case HCI_SUBEVENT_LE_GENERATE_DHKEY_COMPLETE: 3273 sm_conn = sm_get_connection_for_handle(sm_active_connection_handle); 3274 if (hci_subevent_le_generate_dhkey_complete_get_status(packet)){ 3275 log_error("Generate DHKEY failed -> abort"); 3276 // abort pairing with 'unspecified reason' 3277 sm_pdu_received_in_wrong_state(sm_conn); 3278 break; 3279 } 3280 3281 hci_subevent_le_generate_dhkey_complete_get_dhkey(packet, &setup->sm_dhkey[0]); 3282 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 3283 log_info("dhkey"); 3284 log_info_hexdump(&setup->sm_dhkey[0], 32); 3285 3286 // trigger next step 3287 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 3288 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 3289 } 3290 break; 3291 #endif 3292 default: 3293 break; 3294 } 3295 break; 3296 3297 case HCI_EVENT_ENCRYPTION_CHANGE: 3298 con_handle = little_endian_read_16(packet, 3); 3299 sm_conn = sm_get_connection_for_handle(con_handle); 3300 if (!sm_conn) break; 3301 3302 sm_conn->sm_connection_encrypted = packet[5]; 3303 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3304 sm_conn->sm_actual_encryption_key_size); 3305 log_info("event handler, state %u", sm_conn->sm_engine_state); 3306 if (!sm_conn->sm_connection_encrypted) break; 3307 // continue if part of initial pairing 3308 switch (sm_conn->sm_engine_state){ 3309 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3310 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3311 sm_done_for_handle(sm_conn->sm_handle); 3312 break; 3313 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3314 if (IS_RESPONDER(sm_conn->sm_role)){ 3315 // slave 3316 if (setup->sm_use_secure_connections){ 3317 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3318 } else { 3319 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3320 } 3321 } else { 3322 // master 3323 if (sm_key_distribution_all_received(sm_conn)){ 3324 // skip receiving keys as there are none 3325 sm_key_distribution_handle_all_received(sm_conn); 3326 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3327 } else { 3328 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3329 } 3330 } 3331 break; 3332 default: 3333 break; 3334 } 3335 break; 3336 3337 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3338 con_handle = little_endian_read_16(packet, 3); 3339 sm_conn = sm_get_connection_for_handle(con_handle); 3340 if (!sm_conn) break; 3341 3342 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3343 log_info("event handler, state %u", sm_conn->sm_engine_state); 3344 // continue if part of initial pairing 3345 switch (sm_conn->sm_engine_state){ 3346 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3347 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3348 sm_done_for_handle(sm_conn->sm_handle); 3349 break; 3350 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3351 if (IS_RESPONDER(sm_conn->sm_role)){ 3352 // slave 3353 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3354 } else { 3355 // master 3356 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3357 } 3358 break; 3359 default: 3360 break; 3361 } 3362 break; 3363 3364 3365 case HCI_EVENT_DISCONNECTION_COMPLETE: 3366 con_handle = little_endian_read_16(packet, 3); 3367 sm_done_for_handle(con_handle); 3368 sm_conn = sm_get_connection_for_handle(con_handle); 3369 if (!sm_conn) break; 3370 3371 // delete stored bonding on disconnect with authentication failure in ph0 3372 if (sm_conn->sm_role == 0 3373 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3374 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3375 le_device_db_remove(sm_conn->sm_le_db_index); 3376 } 3377 3378 // pairing failed, if it was ongoing 3379 if (sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED && sm_conn->sm_engine_state != SM_GENERAL_IDLE){ 3380 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3381 } 3382 3383 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3384 sm_conn->sm_handle = 0; 3385 break; 3386 3387 case HCI_EVENT_COMMAND_COMPLETE: 3388 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3389 sm_handle_encryption_result(&packet[6]); 3390 break; 3391 } 3392 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3393 sm_handle_random_result(&packet[6]); 3394 break; 3395 } 3396 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3397 // set local addr for le device db 3398 bd_addr_t addr; 3399 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3400 le_device_db_set_local_bd_addr(addr); 3401 } 3402 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_local_supported_commands)){ 3403 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3404 if ((packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE+1+34] & 0x06) != 0x06){ 3405 // mbedTLS can also be used if already available (and malloc is supported) 3406 log_error("LE Secure Connections enabled, but HCI Controller doesn't support it. Please add USE_MICRO_ECC_FOR_ECDH to btstack_config.h"); 3407 } 3408 #endif 3409 } 3410 break; 3411 default: 3412 break; 3413 } 3414 break; 3415 default: 3416 break; 3417 } 3418 3419 sm_run(); 3420 } 3421 3422 static inline int sm_calc_actual_encryption_key_size(int other){ 3423 if (other < sm_min_encryption_key_size) return 0; 3424 if (other < sm_max_encryption_key_size) return other; 3425 return sm_max_encryption_key_size; 3426 } 3427 3428 3429 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3430 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3431 switch (method){ 3432 case JUST_WORKS: 3433 case NK_BOTH_INPUT: 3434 return 1; 3435 default: 3436 return 0; 3437 } 3438 } 3439 // responder 3440 3441 static int sm_passkey_used(stk_generation_method_t method){ 3442 switch (method){ 3443 case PK_RESP_INPUT: 3444 return 1; 3445 default: 3446 return 0; 3447 } 3448 } 3449 #endif 3450 3451 /** 3452 * @return ok 3453 */ 3454 static int sm_validate_stk_generation_method(void){ 3455 // check if STK generation method is acceptable by client 3456 switch (setup->sm_stk_generation_method){ 3457 case JUST_WORKS: 3458 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3459 case PK_RESP_INPUT: 3460 case PK_INIT_INPUT: 3461 case OK_BOTH_INPUT: 3462 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3463 case OOB: 3464 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3465 case NK_BOTH_INPUT: 3466 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3467 return 1; 3468 default: 3469 return 0; 3470 } 3471 } 3472 3473 // size of complete sm_pdu used to validate input 3474 static const uint8_t sm_pdu_size[] = { 3475 0, // 0x00 invalid opcode 3476 7, // 0x01 pairing request 3477 7, // 0x02 pairing response 3478 17, // 0x03 pairing confirm 3479 17, // 0x04 pairing random 3480 2, // 0x05 pairing failed 3481 17, // 0x06 encryption information 3482 11, // 0x07 master identification 3483 17, // 0x08 identification information 3484 8, // 0x09 identify address information 3485 17, // 0x0a signing information 3486 2, // 0x0b security request 3487 65, // 0x0c pairing public key 3488 17, // 0x0d pairing dhk check 3489 2, // 0x0e keypress notification 3490 }; 3491 3492 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3493 3494 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3495 sm_run(); 3496 } 3497 3498 if (packet_type != SM_DATA_PACKET) return; 3499 if (size == 0) return; 3500 3501 uint8_t sm_pdu_code = packet[0]; 3502 3503 // validate pdu size 3504 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3505 if (sm_pdu_size[sm_pdu_code] != size) return; 3506 3507 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3508 if (!sm_conn) return; 3509 3510 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3511 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3512 sm_done_for_handle(con_handle); 3513 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3514 return; 3515 } 3516 3517 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3518 3519 int err; 3520 UNUSED(err); 3521 3522 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3523 uint8_t buffer[5]; 3524 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3525 buffer[1] = 3; 3526 little_endian_store_16(buffer, 2, con_handle); 3527 buffer[4] = packet[1]; 3528 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3529 return; 3530 } 3531 3532 switch (sm_conn->sm_engine_state){ 3533 3534 // a sm timeout requries a new physical connection 3535 case SM_GENERAL_TIMEOUT: 3536 return; 3537 3538 #ifdef ENABLE_LE_CENTRAL 3539 3540 // Initiator 3541 case SM_INITIATOR_CONNECTED: 3542 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3543 sm_pdu_received_in_wrong_state(sm_conn); 3544 break; 3545 } 3546 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3547 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3548 break; 3549 } 3550 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3551 sm_key_t ltk; 3552 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3553 if (!sm_is_null_key(ltk)){ 3554 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3555 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3556 } else { 3557 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3558 } 3559 break; 3560 } 3561 // otherwise, store security request 3562 sm_conn->sm_security_request_received = 1; 3563 break; 3564 3565 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3566 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3567 sm_pdu_received_in_wrong_state(sm_conn); 3568 break; 3569 } 3570 3571 // store pairing request 3572 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3573 err = sm_stk_generation_init(sm_conn); 3574 3575 #ifdef ENABLE_TESTING_SUPPORT 3576 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3577 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3578 err = test_pairing_failure; 3579 } 3580 #endif 3581 3582 if (err){ 3583 setup->sm_pairing_failed_reason = err; 3584 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3585 break; 3586 } 3587 3588 // generate random number first, if we need to show passkey 3589 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3590 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3591 break; 3592 } 3593 3594 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3595 if (setup->sm_use_secure_connections){ 3596 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3597 if (setup->sm_stk_generation_method == JUST_WORKS){ 3598 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3599 sm_trigger_user_response(sm_conn); 3600 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3601 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3602 } 3603 } else { 3604 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3605 } 3606 break; 3607 } 3608 #endif 3609 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3610 sm_trigger_user_response(sm_conn); 3611 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3612 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3613 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3614 } 3615 break; 3616 3617 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3618 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3619 sm_pdu_received_in_wrong_state(sm_conn); 3620 break; 3621 } 3622 3623 // store s_confirm 3624 reverse_128(&packet[1], setup->sm_peer_confirm); 3625 3626 #ifdef ENABLE_TESTING_SUPPORT 3627 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3628 log_info("testing_support: reset confirm value"); 3629 memset(setup->sm_peer_confirm, 0, 16); 3630 } 3631 #endif 3632 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3633 break; 3634 3635 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3636 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3637 sm_pdu_received_in_wrong_state(sm_conn); 3638 break;; 3639 } 3640 3641 // received random value 3642 reverse_128(&packet[1], setup->sm_peer_random); 3643 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3644 break; 3645 #endif 3646 3647 #ifdef ENABLE_LE_PERIPHERAL 3648 // Responder 3649 case SM_RESPONDER_IDLE: 3650 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3651 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3652 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3653 sm_pdu_received_in_wrong_state(sm_conn); 3654 break;; 3655 } 3656 3657 // store pairing request 3658 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3659 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3660 break; 3661 #endif 3662 3663 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3664 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3665 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3666 sm_pdu_received_in_wrong_state(sm_conn); 3667 break; 3668 } 3669 3670 // store public key for DH Key calculation 3671 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3672 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3673 3674 // validate public key using micro-ecc 3675 err = 0; 3676 3677 #ifdef USE_MICRO_ECC_FOR_ECDH 3678 #if uECC_SUPPORTS_secp256r1 3679 // standard version 3680 err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0; 3681 #else 3682 // static version 3683 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3684 #endif 3685 #endif 3686 3687 #ifdef USE_MBEDTLS_FOR_ECDH 3688 mbedtls_ecp_point Q; 3689 mbedtls_ecp_point_init( &Q ); 3690 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); 3691 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 3692 mbedtls_mpi_lset(&Q.Z, 1); 3693 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3694 mbedtls_ecp_point_free( & Q); 3695 #endif 3696 3697 if (err){ 3698 log_error("sm: peer public key invalid %x", err); 3699 // uses "unspecified reason", there is no "public key invalid" error code 3700 sm_pdu_received_in_wrong_state(sm_conn); 3701 break; 3702 } 3703 3704 #ifndef USE_SOFTWARE_ECDH_IMPLEMENTATION 3705 // ask controller to calculate dhkey 3706 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_NEEDED; 3707 #endif 3708 3709 if (IS_RESPONDER(sm_conn->sm_role)){ 3710 // responder 3711 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3712 } else { 3713 // initiator 3714 // stk generation method 3715 // passkey entry: notify app to show passkey or to request passkey 3716 switch (setup->sm_stk_generation_method){ 3717 case JUST_WORKS: 3718 case NK_BOTH_INPUT: 3719 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3720 break; 3721 case PK_RESP_INPUT: 3722 sm_sc_start_calculating_local_confirm(sm_conn); 3723 break; 3724 case PK_INIT_INPUT: 3725 case OK_BOTH_INPUT: 3726 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3727 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3728 break; 3729 } 3730 sm_sc_start_calculating_local_confirm(sm_conn); 3731 break; 3732 case OOB: 3733 // TODO: implement SC OOB 3734 break; 3735 } 3736 } 3737 break; 3738 3739 case SM_SC_W4_CONFIRMATION: 3740 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3741 sm_pdu_received_in_wrong_state(sm_conn); 3742 break; 3743 } 3744 // received confirm value 3745 reverse_128(&packet[1], setup->sm_peer_confirm); 3746 3747 #ifdef ENABLE_TESTING_SUPPORT 3748 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3749 log_info("testing_support: reset confirm value"); 3750 memset(setup->sm_peer_confirm, 0, 16); 3751 } 3752 #endif 3753 if (IS_RESPONDER(sm_conn->sm_role)){ 3754 // responder 3755 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3756 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3757 // still waiting for passkey 3758 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3759 break; 3760 } 3761 } 3762 sm_sc_start_calculating_local_confirm(sm_conn); 3763 } else { 3764 // initiator 3765 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3766 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3767 } else { 3768 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3769 } 3770 } 3771 break; 3772 3773 case SM_SC_W4_PAIRING_RANDOM: 3774 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3775 sm_pdu_received_in_wrong_state(sm_conn); 3776 break; 3777 } 3778 3779 // received random value 3780 reverse_128(&packet[1], setup->sm_peer_nonce); 3781 3782 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3783 // only check for JUST WORK/NC in initiator role OR passkey entry 3784 if (!IS_RESPONDER(sm_conn->sm_role) || sm_passkey_used(setup->sm_stk_generation_method)) { 3785 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3786 break; 3787 } 3788 3789 sm_sc_state_after_receiving_random(sm_conn); 3790 break; 3791 3792 case SM_SC_W2_CALCULATE_G2: 3793 case SM_SC_W4_CALCULATE_G2: 3794 case SM_SC_W4_CALCULATE_DHKEY: 3795 case SM_SC_W2_CALCULATE_F5_SALT: 3796 case SM_SC_W4_CALCULATE_F5_SALT: 3797 case SM_SC_W2_CALCULATE_F5_MACKEY: 3798 case SM_SC_W4_CALCULATE_F5_MACKEY: 3799 case SM_SC_W2_CALCULATE_F5_LTK: 3800 case SM_SC_W4_CALCULATE_F5_LTK: 3801 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3802 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3803 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3804 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3805 sm_pdu_received_in_wrong_state(sm_conn); 3806 break; 3807 } 3808 // store DHKey Check 3809 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3810 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3811 3812 // have we been only waiting for dhkey check command? 3813 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3814 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3815 } 3816 break; 3817 #endif 3818 3819 #ifdef ENABLE_LE_PERIPHERAL 3820 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3821 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3822 sm_pdu_received_in_wrong_state(sm_conn); 3823 break; 3824 } 3825 3826 // received confirm value 3827 reverse_128(&packet[1], setup->sm_peer_confirm); 3828 3829 #ifdef ENABLE_TESTING_SUPPORT 3830 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3831 log_info("testing_support: reset confirm value"); 3832 memset(setup->sm_peer_confirm, 0, 16); 3833 } 3834 #endif 3835 // notify client to hide shown passkey 3836 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3837 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3838 } 3839 3840 // handle user cancel pairing? 3841 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3842 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3843 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3844 break; 3845 } 3846 3847 // wait for user action? 3848 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3849 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3850 break; 3851 } 3852 3853 // calculate and send local_confirm 3854 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3855 break; 3856 3857 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3858 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3859 sm_pdu_received_in_wrong_state(sm_conn); 3860 break;; 3861 } 3862 3863 // received random value 3864 reverse_128(&packet[1], setup->sm_peer_random); 3865 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3866 break; 3867 #endif 3868 3869 case SM_PH3_RECEIVE_KEYS: 3870 switch(sm_pdu_code){ 3871 case SM_CODE_ENCRYPTION_INFORMATION: 3872 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3873 reverse_128(&packet[1], setup->sm_peer_ltk); 3874 break; 3875 3876 case SM_CODE_MASTER_IDENTIFICATION: 3877 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3878 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3879 reverse_64(&packet[3], setup->sm_peer_rand); 3880 break; 3881 3882 case SM_CODE_IDENTITY_INFORMATION: 3883 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3884 reverse_128(&packet[1], setup->sm_peer_irk); 3885 break; 3886 3887 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3888 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3889 setup->sm_peer_addr_type = packet[1]; 3890 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3891 break; 3892 3893 case SM_CODE_SIGNING_INFORMATION: 3894 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3895 reverse_128(&packet[1], setup->sm_peer_csrk); 3896 break; 3897 default: 3898 // Unexpected PDU 3899 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3900 break; 3901 } 3902 // done with key distribution? 3903 if (sm_key_distribution_all_received(sm_conn)){ 3904 3905 sm_key_distribution_handle_all_received(sm_conn); 3906 3907 if (IS_RESPONDER(sm_conn->sm_role)){ 3908 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3909 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3910 } else { 3911 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3912 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3913 sm_done_for_handle(sm_conn->sm_handle); 3914 } 3915 } else { 3916 if (setup->sm_use_secure_connections){ 3917 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3918 } else { 3919 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3920 } 3921 } 3922 } 3923 break; 3924 default: 3925 // Unexpected PDU 3926 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3927 break; 3928 } 3929 3930 // try to send preparared packet 3931 sm_run(); 3932 } 3933 3934 // Security Manager Client API 3935 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3936 sm_get_oob_data = get_oob_data_callback; 3937 } 3938 3939 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3940 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3941 } 3942 3943 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3944 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3945 } 3946 3947 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3948 sm_min_encryption_key_size = min_size; 3949 sm_max_encryption_key_size = max_size; 3950 } 3951 3952 void sm_set_authentication_requirements(uint8_t auth_req){ 3953 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3954 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3955 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3956 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3957 } 3958 #endif 3959 sm_auth_req = auth_req; 3960 } 3961 3962 void sm_set_io_capabilities(io_capability_t io_capability){ 3963 sm_io_capabilities = io_capability; 3964 } 3965 3966 #ifdef ENABLE_LE_PERIPHERAL 3967 void sm_set_request_security(int enable){ 3968 sm_slave_request_security = enable; 3969 } 3970 #endif 3971 3972 void sm_set_er(sm_key_t er){ 3973 memcpy(sm_persistent_er, er, 16); 3974 } 3975 3976 void sm_set_ir(sm_key_t ir){ 3977 memcpy(sm_persistent_ir, ir, 16); 3978 } 3979 3980 // Testing support only 3981 void sm_test_set_irk(sm_key_t irk){ 3982 memcpy(sm_persistent_irk, irk, 16); 3983 sm_persistent_irk_ready = 1; 3984 } 3985 3986 void sm_test_use_fixed_local_csrk(void){ 3987 test_use_fixed_local_csrk = 1; 3988 } 3989 3990 #ifdef ENABLE_TESTING_SUPPORT 3991 void sm_test_set_pairing_failure(int reason){ 3992 test_pairing_failure = reason; 3993 } 3994 #endif 3995 3996 void sm_init(void){ 3997 // set some (BTstack default) ER and IR 3998 int i; 3999 sm_key_t er; 4000 sm_key_t ir; 4001 for (i=0;i<16;i++){ 4002 er[i] = 0x30 + i; 4003 ir[i] = 0x90 + i; 4004 } 4005 sm_set_er(er); 4006 sm_set_ir(ir); 4007 // defaults 4008 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4009 | SM_STK_GENERATION_METHOD_OOB 4010 | SM_STK_GENERATION_METHOD_PASSKEY 4011 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4012 4013 sm_max_encryption_key_size = 16; 4014 sm_min_encryption_key_size = 7; 4015 4016 sm_fixed_passkey_in_display_role = 0xffffffff; 4017 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4018 4019 #ifdef ENABLE_CMAC_ENGINE 4020 sm_cmac_state = CMAC_IDLE; 4021 #endif 4022 dkg_state = DKG_W4_WORKING; 4023 rau_state = RAU_W4_WORKING; 4024 sm_aes128_state = SM_AES128_IDLE; 4025 sm_address_resolution_test = -1; // no private address to resolve yet 4026 sm_address_resolution_ah_calculation_active = 0; 4027 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4028 sm_address_resolution_general_queue = NULL; 4029 4030 gap_random_adress_update_period = 15 * 60 * 1000L; 4031 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4032 4033 test_use_fixed_local_csrk = 0; 4034 4035 // register for HCI Events from HCI 4036 hci_event_callback_registration.callback = &sm_event_packet_handler; 4037 hci_add_event_handler(&hci_event_callback_registration); 4038 4039 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4040 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4041 4042 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4043 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4044 #endif 4045 4046 #ifdef USE_MBEDTLS_FOR_ECDH 4047 mbedtls_ecp_group_init(&mbedtls_ec_group); 4048 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 4049 #endif 4050 } 4051 4052 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 4053 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4054 memcpy(&ec_q[0], qx, 32); 4055 memcpy(&ec_q[32], qy, 32); 4056 memcpy(ec_d, d, 32); 4057 sm_have_ec_keypair = 1; 4058 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4059 #else 4060 UNUSED(qx); 4061 UNUSED(qy); 4062 UNUSED(d); 4063 #endif 4064 } 4065 4066 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4067 static void parse_hex(uint8_t * buffer, const char * hex_string){ 4068 while (*hex_string){ 4069 int high_nibble = nibble_for_char(*hex_string++); 4070 int low_nibble = nibble_for_char(*hex_string++); 4071 *buffer++ = (high_nibble << 4) | low_nibble; 4072 } 4073 } 4074 #endif 4075 4076 void sm_test_use_fixed_ec_keypair(void){ 4077 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4078 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 4079 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 4080 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 4081 parse_hex(ec_d, ec_d_string); 4082 parse_hex(&ec_q[0], ec_qx_string); 4083 parse_hex(&ec_q[32], ec_qy_string); 4084 sm_have_ec_keypair = 1; 4085 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4086 #endif 4087 } 4088 4089 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4090 sm_fixed_passkey_in_display_role = passkey; 4091 } 4092 4093 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4094 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4095 } 4096 4097 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4098 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4099 if (!hci_con) return NULL; 4100 return &hci_con->sm_connection; 4101 } 4102 4103 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4104 switch (sm_conn->sm_engine_state){ 4105 case SM_GENERAL_IDLE: 4106 case SM_RESPONDER_IDLE: 4107 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4108 sm_run(); 4109 break; 4110 default: 4111 break; 4112 } 4113 } 4114 4115 /** 4116 * @brief Trigger Security Request 4117 */ 4118 void sm_send_security_request(hci_con_handle_t con_handle){ 4119 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4120 if (!sm_conn) return; 4121 sm_send_security_request_for_connection(sm_conn); 4122 } 4123 4124 // request pairing 4125 void sm_request_pairing(hci_con_handle_t con_handle){ 4126 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4127 if (!sm_conn) return; // wrong connection 4128 4129 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4130 if (IS_RESPONDER(sm_conn->sm_role)){ 4131 sm_send_security_request_for_connection(sm_conn); 4132 } else { 4133 // used as a trigger to start central/master/initiator security procedures 4134 uint16_t ediv; 4135 sm_key_t ltk; 4136 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4137 switch (sm_conn->sm_irk_lookup_state){ 4138 case IRK_LOOKUP_FAILED: 4139 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4140 break; 4141 case IRK_LOOKUP_SUCCEEDED: 4142 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 4143 if (!sm_is_null_key(ltk) || ediv){ 4144 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 4145 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4146 } else { 4147 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4148 } 4149 break; 4150 default: 4151 sm_conn->sm_pairing_requested = 1; 4152 break; 4153 } 4154 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4155 sm_conn->sm_pairing_requested = 1; 4156 } 4157 } 4158 sm_run(); 4159 } 4160 4161 // called by client app on authorization request 4162 void sm_authorization_decline(hci_con_handle_t con_handle){ 4163 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4164 if (!sm_conn) return; // wrong connection 4165 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4166 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4167 } 4168 4169 void sm_authorization_grant(hci_con_handle_t con_handle){ 4170 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4171 if (!sm_conn) return; // wrong connection 4172 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4173 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4174 } 4175 4176 // GAP Bonding API 4177 4178 void sm_bonding_decline(hci_con_handle_t con_handle){ 4179 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4180 if (!sm_conn) return; // wrong connection 4181 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4182 log_info("decline, state %u", sm_conn->sm_engine_state); 4183 switch(sm_conn->sm_engine_state){ 4184 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4185 case SM_SC_W4_USER_RESPONSE: 4186 case SM_SC_W4_CONFIRMATION: 4187 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4188 #endif 4189 case SM_PH1_W4_USER_RESPONSE: 4190 switch (setup->sm_stk_generation_method){ 4191 case PK_RESP_INPUT: 4192 case PK_INIT_INPUT: 4193 case OK_BOTH_INPUT: 4194 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4195 break; 4196 case NK_BOTH_INPUT: 4197 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4198 break; 4199 case JUST_WORKS: 4200 case OOB: 4201 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4202 break; 4203 } 4204 break; 4205 default: 4206 break; 4207 } 4208 sm_run(); 4209 } 4210 4211 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4212 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4213 if (!sm_conn) return; // wrong connection 4214 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4215 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4216 if (setup->sm_use_secure_connections){ 4217 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4218 } else { 4219 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4220 } 4221 } 4222 4223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4224 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4225 sm_sc_prepare_dhkey_check(sm_conn); 4226 } 4227 #endif 4228 4229 sm_run(); 4230 } 4231 4232 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4233 // for now, it's the same 4234 sm_just_works_confirm(con_handle); 4235 } 4236 4237 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4238 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4239 if (!sm_conn) return; // wrong connection 4240 sm_reset_tk(); 4241 big_endian_store_32(setup->sm_tk, 12, passkey); 4242 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4243 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4244 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4245 } 4246 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4247 memcpy(setup->sm_ra, setup->sm_tk, 16); 4248 memcpy(setup->sm_rb, setup->sm_tk, 16); 4249 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4250 sm_sc_start_calculating_local_confirm(sm_conn); 4251 } 4252 #endif 4253 sm_run(); 4254 } 4255 4256 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4257 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4258 if (!sm_conn) return; // wrong connection 4259 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4260 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4261 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4262 switch (action){ 4263 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4264 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4265 flags |= (1 << action); 4266 break; 4267 case SM_KEYPRESS_PASSKEY_CLEARED: 4268 // clear counter, keypress & erased flags + set passkey cleared 4269 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4270 break; 4271 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4272 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4273 // erase actions queued 4274 num_actions--; 4275 if (num_actions == 0){ 4276 // clear counter, keypress & erased flags 4277 flags &= 0x19; 4278 } 4279 break; 4280 } 4281 num_actions++; 4282 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4283 break; 4284 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4285 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4286 // enter actions queued 4287 num_actions--; 4288 if (num_actions == 0){ 4289 // clear counter, keypress & erased flags 4290 flags &= 0x19; 4291 } 4292 break; 4293 } 4294 num_actions++; 4295 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4296 break; 4297 default: 4298 break; 4299 } 4300 setup->sm_keypress_notification = (num_actions << 5) | flags; 4301 sm_run(); 4302 } 4303 4304 /** 4305 * @brief Identify device in LE Device DB 4306 * @param handle 4307 * @returns index from le_device_db or -1 if not found/identified 4308 */ 4309 int sm_le_device_index(hci_con_handle_t con_handle ){ 4310 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4311 if (!sm_conn) return -1; 4312 return sm_conn->sm_le_db_index; 4313 } 4314 4315 static int gap_random_address_type_requires_updates(void){ 4316 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4317 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4318 return 1; 4319 } 4320 4321 static uint8_t own_address_type(void){ 4322 switch (gap_random_adress_type){ 4323 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4324 return BD_ADDR_TYPE_LE_PUBLIC; 4325 default: 4326 return BD_ADDR_TYPE_LE_RANDOM; 4327 } 4328 } 4329 4330 // GAP LE API 4331 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4332 gap_random_address_update_stop(); 4333 gap_random_adress_type = random_address_type; 4334 hci_le_set_own_address_type(own_address_type()); 4335 if (!gap_random_address_type_requires_updates()) return; 4336 gap_random_address_update_start(); 4337 gap_random_address_trigger(); 4338 } 4339 4340 gap_random_address_type_t gap_random_address_get_mode(void){ 4341 return gap_random_adress_type; 4342 } 4343 4344 void gap_random_address_set_update_period(int period_ms){ 4345 gap_random_adress_update_period = period_ms; 4346 if (!gap_random_address_type_requires_updates()) return; 4347 gap_random_address_update_stop(); 4348 gap_random_address_update_start(); 4349 } 4350 4351 void gap_random_address_set(bd_addr_t addr){ 4352 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4353 memcpy(sm_random_address, addr, 6); 4354 if (rau_state == RAU_W4_WORKING) return; 4355 rau_state = RAU_SET_ADDRESS; 4356 sm_run(); 4357 } 4358 4359 #ifdef ENABLE_LE_PERIPHERAL 4360 /* 4361 * @brief Set Advertisement Paramters 4362 * @param adv_int_min 4363 * @param adv_int_max 4364 * @param adv_type 4365 * @param direct_address_type 4366 * @param direct_address 4367 * @param channel_map 4368 * @param filter_policy 4369 * 4370 * @note own_address_type is used from gap_random_address_set_mode 4371 */ 4372 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4373 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4374 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4375 direct_address_typ, direct_address, channel_map, filter_policy); 4376 } 4377 #endif 4378