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); 784 785 786 // decide if OOB will be used based on SC vs. Legacy and oob flags 787 int use_oob = 0; 788 if (setup->sm_use_secure_connections){ 789 // In LE Secure Connections pairing, the out of band method is used if at least 790 // one device has the peer device's out of band authentication data available. 791 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 792 } else { 793 // In LE legacy pairing, the out of band method is used if both the devices have 794 // the other device's out of band authentication data available. 795 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 796 } 797 if (use_oob){ 798 log_info("SM: have OOB data"); 799 log_info_key("OOB", setup->sm_tk); 800 setup->sm_stk_generation_method = OOB; 801 return; 802 } 803 804 // If both devices have not set the MITM option in the Authentication Requirements 805 // Flags, then the IO capabilities shall be ignored and the Just Works association 806 // model shall be used. 807 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 808 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 809 log_info("SM: MITM not required by both -> JUST WORKS"); 810 return; 811 } 812 813 // Reset TK as it has been setup in sm_init_setup 814 sm_reset_tk(); 815 816 // Also use just works if unknown io capabilites 817 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)){ 818 return; 819 } 820 821 // Otherwise the IO capabilities of the devices shall be used to determine the 822 // pairing method as defined in Table 2.4. 823 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 824 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 825 826 #ifdef ENABLE_LE_SECURE_CONNECTIONS 827 // table not define by default 828 if (setup->sm_use_secure_connections){ 829 generation_method = stk_generation_method_with_secure_connection; 830 } 831 #endif 832 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)]; 833 834 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 835 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); 836 } 837 838 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 839 int flags = 0; 840 if (key_set & SM_KEYDIST_ENC_KEY){ 841 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 842 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 843 } 844 if (key_set & SM_KEYDIST_ID_KEY){ 845 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 846 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 847 } 848 if (key_set & SM_KEYDIST_SIGN){ 849 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 850 } 851 return flags; 852 } 853 854 static void sm_setup_key_distribution(uint8_t key_set){ 855 setup->sm_key_distribution_received_set = 0; 856 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 857 } 858 859 // CSRK Key Lookup 860 861 862 static int sm_address_resolution_idle(void){ 863 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 864 } 865 866 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){ 867 memcpy(sm_address_resolution_address, addr, 6); 868 sm_address_resolution_addr_type = addr_type; 869 sm_address_resolution_test = 0; 870 sm_address_resolution_mode = mode; 871 sm_address_resolution_context = context; 872 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 873 } 874 875 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 876 // check if already in list 877 btstack_linked_list_iterator_t it; 878 sm_lookup_entry_t * entry; 879 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 880 while(btstack_linked_list_iterator_has_next(&it)){ 881 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 882 if (entry->address_type != address_type) continue; 883 if (memcmp(entry->address, address, 6)) continue; 884 // already in list 885 return BTSTACK_BUSY; 886 } 887 entry = btstack_memory_sm_lookup_entry_get(); 888 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 889 entry->address_type = (bd_addr_type_t) address_type; 890 memcpy(entry->address, address, 6); 891 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 892 sm_run(); 893 return 0; 894 } 895 896 // 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 897 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 898 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 899 } 900 static inline void dkg_next_state(void){ 901 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 902 } 903 static inline void rau_next_state(void){ 904 rau_state = (random_address_update_t) (((int)rau_state) + 1); 905 } 906 907 // CMAC calculation using AES Engine 908 #ifdef ENABLE_CMAC_ENGINE 909 910 static inline void sm_cmac_next_state(void){ 911 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 912 } 913 914 static int sm_cmac_last_block_complete(void){ 915 if (sm_cmac_message_len == 0) return 0; 916 return (sm_cmac_message_len & 0x0f) == 0; 917 } 918 919 int sm_cmac_ready(void){ 920 return sm_cmac_state == CMAC_IDLE; 921 } 922 923 // generic cmac calculation 924 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])){ 925 // Generalized CMAC 926 memcpy(sm_cmac_k, key, 16); 927 memset(sm_cmac_x, 0, 16); 928 sm_cmac_block_current = 0; 929 sm_cmac_message_len = message_len; 930 sm_cmac_done_handler = done_callback; 931 sm_cmac_get_byte = get_byte_callback; 932 933 // step 2: n := ceil(len/const_Bsize); 934 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 935 936 // step 3: .. 937 if (sm_cmac_block_count==0){ 938 sm_cmac_block_count = 1; 939 } 940 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 941 942 // first, we need to compute l for k1, k2, and m_last 943 sm_cmac_state = CMAC_CALC_SUBKEYS; 944 945 // let's go 946 sm_run(); 947 } 948 #endif 949 950 // cmac for ATT Message signing 951 #ifdef ENABLE_LE_SIGNED_WRITE 952 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 953 if (offset >= sm_cmac_message_len) { 954 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 955 return 0; 956 } 957 958 offset = sm_cmac_message_len - 1 - offset; 959 960 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 961 if (offset < 3){ 962 return sm_cmac_header[offset]; 963 } 964 int actual_message_len_incl_header = sm_cmac_message_len - 4; 965 if (offset < actual_message_len_incl_header){ 966 return sm_cmac_message[offset - 3]; 967 } 968 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 969 } 970 971 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)){ 972 // ATT Message Signing 973 sm_cmac_header[0] = opcode; 974 little_endian_store_16(sm_cmac_header, 1, con_handle); 975 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 976 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 977 sm_cmac_message = message; 978 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 979 } 980 #endif 981 982 #ifdef ENABLE_CMAC_ENGINE 983 static void sm_cmac_handle_aes_engine_ready(void){ 984 switch (sm_cmac_state){ 985 case CMAC_CALC_SUBKEYS: { 986 sm_key_t const_zero; 987 memset(const_zero, 0, 16); 988 sm_cmac_next_state(); 989 sm_aes128_start(sm_cmac_k, const_zero, NULL); 990 break; 991 } 992 case CMAC_CALC_MI: { 993 int j; 994 sm_key_t y; 995 for (j=0;j<16;j++){ 996 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 997 } 998 sm_cmac_block_current++; 999 sm_cmac_next_state(); 1000 sm_aes128_start(sm_cmac_k, y, NULL); 1001 break; 1002 } 1003 case CMAC_CALC_MLAST: { 1004 int i; 1005 sm_key_t y; 1006 for (i=0;i<16;i++){ 1007 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1008 } 1009 log_info_key("Y", y); 1010 sm_cmac_block_current++; 1011 sm_cmac_next_state(); 1012 sm_aes128_start(sm_cmac_k, y, NULL); 1013 break; 1014 } 1015 default: 1016 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1017 break; 1018 } 1019 } 1020 1021 // CMAC Implementation using AES128 engine 1022 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1023 int i; 1024 int carry = 0; 1025 for (i=len-1; i >= 0 ; i--){ 1026 int new_carry = data[i] >> 7; 1027 data[i] = data[i] << 1 | carry; 1028 carry = new_carry; 1029 } 1030 } 1031 1032 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1033 switch (sm_cmac_state){ 1034 case CMAC_W4_SUBKEYS: { 1035 sm_key_t k1; 1036 memcpy(k1, data, 16); 1037 sm_shift_left_by_one_bit_inplace(16, k1); 1038 if (data[0] & 0x80){ 1039 k1[15] ^= 0x87; 1040 } 1041 sm_key_t k2; 1042 memcpy(k2, k1, 16); 1043 sm_shift_left_by_one_bit_inplace(16, k2); 1044 if (k1[0] & 0x80){ 1045 k2[15] ^= 0x87; 1046 } 1047 1048 log_info_key("k", sm_cmac_k); 1049 log_info_key("k1", k1); 1050 log_info_key("k2", k2); 1051 1052 // step 4: set m_last 1053 int i; 1054 if (sm_cmac_last_block_complete()){ 1055 for (i=0;i<16;i++){ 1056 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1057 } 1058 } else { 1059 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1060 for (i=0;i<16;i++){ 1061 if (i < valid_octets_in_last_block){ 1062 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1063 continue; 1064 } 1065 if (i == valid_octets_in_last_block){ 1066 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1067 continue; 1068 } 1069 sm_cmac_m_last[i] = k2[i]; 1070 } 1071 } 1072 1073 // next 1074 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1075 break; 1076 } 1077 case CMAC_W4_MI: 1078 memcpy(sm_cmac_x, data, 16); 1079 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1080 break; 1081 case CMAC_W4_MLAST: 1082 // done 1083 log_info("Setting CMAC Engine to IDLE"); 1084 sm_cmac_state = CMAC_IDLE; 1085 log_info_key("CMAC", data); 1086 sm_cmac_done_handler(data); 1087 break; 1088 default: 1089 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1090 break; 1091 } 1092 } 1093 #endif 1094 1095 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1096 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1097 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1098 switch (setup->sm_stk_generation_method){ 1099 case PK_RESP_INPUT: 1100 if (IS_RESPONDER(sm_conn->sm_role)){ 1101 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1102 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1103 } else { 1104 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)); 1105 } 1106 break; 1107 case PK_INIT_INPUT: 1108 if (IS_RESPONDER(sm_conn->sm_role)){ 1109 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)); 1110 } else { 1111 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1112 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1113 } 1114 break; 1115 case OK_BOTH_INPUT: 1116 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1117 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1118 break; 1119 case NK_BOTH_INPUT: 1120 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1121 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)); 1122 break; 1123 case JUST_WORKS: 1124 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1125 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1126 break; 1127 case OOB: 1128 // client already provided OOB data, let's skip notification. 1129 break; 1130 } 1131 } 1132 1133 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1134 int recv_flags; 1135 if (IS_RESPONDER(sm_conn->sm_role)){ 1136 // slave / responder 1137 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1138 } else { 1139 // master / initiator 1140 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1141 } 1142 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1143 return recv_flags == setup->sm_key_distribution_received_set; 1144 } 1145 1146 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1147 if (sm_active_connection_handle == con_handle){ 1148 sm_timeout_stop(); 1149 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1150 log_info("sm: connection 0x%x released setup context", con_handle); 1151 } 1152 } 1153 1154 static int sm_key_distribution_flags_for_auth_req(void){ 1155 1156 int flags = SM_KEYDIST_ID_KEY; 1157 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1158 // encryption and signing information only if bonding requested 1159 flags |= SM_KEYDIST_ENC_KEY; 1160 #ifdef ENABLE_LE_SIGNED_WRITE 1161 flags |= SM_KEYDIST_SIGN; 1162 #endif 1163 } 1164 return flags; 1165 } 1166 1167 static void sm_reset_setup(void){ 1168 // fill in sm setup 1169 setup->sm_state_vars = 0; 1170 setup->sm_keypress_notification = 0; 1171 sm_reset_tk(); 1172 } 1173 1174 static void sm_init_setup(sm_connection_t * sm_conn){ 1175 1176 // fill in sm setup 1177 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1178 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1179 1180 // query client for OOB data 1181 int have_oob_data = 0; 1182 if (sm_get_oob_data) { 1183 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1184 } 1185 1186 sm_pairing_packet_t * local_packet; 1187 if (IS_RESPONDER(sm_conn->sm_role)){ 1188 // slave 1189 local_packet = &setup->sm_s_pres; 1190 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1191 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1192 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1193 } else { 1194 // master 1195 local_packet = &setup->sm_m_preq; 1196 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1197 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1198 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1199 1200 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1201 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1202 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1203 } 1204 1205 uint8_t auth_req = sm_auth_req; 1206 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1207 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1208 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1209 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1210 } 1211 1212 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1213 1214 sm_pairing_packet_t * remote_packet; 1215 int remote_key_request; 1216 if (IS_RESPONDER(sm_conn->sm_role)){ 1217 // slave / responder 1218 remote_packet = &setup->sm_m_preq; 1219 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1220 } else { 1221 // master / initiator 1222 remote_packet = &setup->sm_s_pres; 1223 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1224 } 1225 1226 // check key size 1227 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1228 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1229 1230 // decide on STK generation method 1231 sm_setup_tk(); 1232 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1233 1234 // check if STK generation method is acceptable by client 1235 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1236 1237 // identical to responder 1238 sm_setup_key_distribution(remote_key_request); 1239 1240 // JUST WORKS doens't provide authentication 1241 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1242 1243 return 0; 1244 } 1245 1246 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1247 1248 // cache and reset context 1249 int matched_device_id = sm_address_resolution_test; 1250 address_resolution_mode_t mode = sm_address_resolution_mode; 1251 void * context = sm_address_resolution_context; 1252 1253 // reset context 1254 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1255 sm_address_resolution_context = NULL; 1256 sm_address_resolution_test = -1; 1257 hci_con_handle_t con_handle = 0; 1258 1259 sm_connection_t * sm_connection; 1260 #ifdef ENABLE_LE_CENTRAL 1261 sm_key_t ltk; 1262 #endif 1263 switch (mode){ 1264 case ADDRESS_RESOLUTION_GENERAL: 1265 break; 1266 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1267 sm_connection = (sm_connection_t *) context; 1268 con_handle = sm_connection->sm_handle; 1269 switch (event){ 1270 case ADDRESS_RESOLUTION_SUCEEDED: 1271 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1272 sm_connection->sm_le_db_index = matched_device_id; 1273 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1274 if (sm_connection->sm_role) { 1275 // LTK request received before, IRK required -> start LTK calculation 1276 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1277 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1278 } 1279 break; 1280 } 1281 #ifdef ENABLE_LE_CENTRAL 1282 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1283 sm_connection->sm_security_request_received = 0; 1284 sm_connection->sm_pairing_requested = 0; 1285 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1286 if (!sm_is_null_key(ltk)){ 1287 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1288 } else { 1289 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1290 } 1291 #endif 1292 break; 1293 case ADDRESS_RESOLUTION_FAILED: 1294 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1295 if (sm_connection->sm_role) { 1296 // LTK request received before, IRK required -> negative LTK reply 1297 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1298 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1299 } 1300 break; 1301 } 1302 #ifdef ENABLE_LE_CENTRAL 1303 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1304 sm_connection->sm_security_request_received = 0; 1305 sm_connection->sm_pairing_requested = 0; 1306 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1307 #endif 1308 break; 1309 } 1310 break; 1311 default: 1312 break; 1313 } 1314 1315 switch (event){ 1316 case ADDRESS_RESOLUTION_SUCEEDED: 1317 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1318 break; 1319 case ADDRESS_RESOLUTION_FAILED: 1320 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1321 break; 1322 } 1323 } 1324 1325 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1326 1327 int le_db_index = -1; 1328 1329 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1330 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1331 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1332 & SM_AUTHREQ_BONDING ) != 0; 1333 1334 if (bonding_enabed){ 1335 1336 // lookup device based on IRK 1337 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1338 int i; 1339 for (i=0; i < le_device_db_max_count(); i++){ 1340 sm_key_t irk; 1341 bd_addr_t address; 1342 int address_type; 1343 le_device_db_info(i, &address_type, address, irk); 1344 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1345 log_info("sm: device found for IRK, updating"); 1346 le_db_index = i; 1347 break; 1348 } 1349 } 1350 } 1351 1352 // if not found, lookup via public address if possible 1353 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1354 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1355 int i; 1356 for (i=0; i < le_device_db_max_count(); i++){ 1357 bd_addr_t address; 1358 int address_type; 1359 le_device_db_info(i, &address_type, address, NULL); 1360 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1361 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1362 log_info("sm: device found for public address, updating"); 1363 le_db_index = i; 1364 break; 1365 } 1366 } 1367 } 1368 1369 // if not found, add to db 1370 if (le_db_index < 0) { 1371 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1372 } 1373 1374 if (le_db_index >= 0){ 1375 1376 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1377 1378 #ifdef ENABLE_LE_SIGNED_WRITE 1379 // store local CSRK 1380 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1381 log_info("sm: store local CSRK"); 1382 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1383 le_device_db_local_counter_set(le_db_index, 0); 1384 } 1385 1386 // store remote CSRK 1387 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1388 log_info("sm: store remote CSRK"); 1389 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1390 le_device_db_remote_counter_set(le_db_index, 0); 1391 } 1392 #endif 1393 // store encryption information for secure connections: LTK generated by ECDH 1394 if (setup->sm_use_secure_connections){ 1395 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1396 uint8_t zero_rand[8]; 1397 memset(zero_rand, 0, 8); 1398 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1399 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1400 } 1401 1402 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1403 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1404 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1405 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1406 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1407 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1408 1409 } 1410 } 1411 } else { 1412 log_info("Ignoring received keys, bonding not enabled"); 1413 } 1414 1415 // keep le_db_index 1416 sm_conn->sm_le_db_index = le_db_index; 1417 } 1418 1419 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1420 setup->sm_pairing_failed_reason = reason; 1421 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1422 } 1423 1424 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1425 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1426 } 1427 1428 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1429 1430 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1431 static int sm_passkey_used(stk_generation_method_t method); 1432 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1433 1434 static void sm_log_ec_keypair(void){ 1435 log_info("Elliptic curve: X"); 1436 log_info_hexdump(&ec_q[0],32); 1437 log_info("Elliptic curve: Y"); 1438 log_info_hexdump(&ec_q[32],32); 1439 } 1440 1441 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1442 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1443 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1444 } else { 1445 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1446 } 1447 } 1448 1449 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1450 if (IS_RESPONDER(sm_conn->sm_role)){ 1451 // Responder 1452 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1453 } else { 1454 // Initiator role 1455 switch (setup->sm_stk_generation_method){ 1456 case JUST_WORKS: 1457 sm_sc_prepare_dhkey_check(sm_conn); 1458 break; 1459 1460 case NK_BOTH_INPUT: 1461 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1462 break; 1463 case PK_INIT_INPUT: 1464 case PK_RESP_INPUT: 1465 case OK_BOTH_INPUT: 1466 if (setup->sm_passkey_bit < 20) { 1467 sm_sc_start_calculating_local_confirm(sm_conn); 1468 } else { 1469 sm_sc_prepare_dhkey_check(sm_conn); 1470 } 1471 break; 1472 case OOB: 1473 sm_sc_prepare_dhkey_check(sm_conn); 1474 break; 1475 } 1476 } 1477 } 1478 1479 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1480 return sm_cmac_sc_buffer[offset]; 1481 } 1482 1483 static void sm_sc_cmac_done(uint8_t * hash){ 1484 log_info("sm_sc_cmac_done: "); 1485 log_info_hexdump(hash, 16); 1486 1487 sm_connection_t * sm_conn = sm_cmac_connection; 1488 sm_cmac_connection = NULL; 1489 #ifdef ENABLE_CLASSIC 1490 link_key_type_t link_key_type; 1491 #endif 1492 1493 switch (sm_conn->sm_engine_state){ 1494 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1495 memcpy(setup->sm_local_confirm, hash, 16); 1496 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1497 break; 1498 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1499 // check 1500 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1501 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1502 break; 1503 } 1504 sm_sc_state_after_receiving_random(sm_conn); 1505 break; 1506 case SM_SC_W4_CALCULATE_G2: { 1507 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1508 big_endian_store_32(setup->sm_tk, 12, vab); 1509 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1510 sm_trigger_user_response(sm_conn); 1511 break; 1512 } 1513 case SM_SC_W4_CALCULATE_F5_SALT: 1514 memcpy(setup->sm_t, hash, 16); 1515 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1516 break; 1517 case SM_SC_W4_CALCULATE_F5_MACKEY: 1518 memcpy(setup->sm_mackey, hash, 16); 1519 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1520 break; 1521 case SM_SC_W4_CALCULATE_F5_LTK: 1522 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1523 // Errata Service Release to the Bluetooth Specification: ESR09 1524 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1525 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1526 memcpy(setup->sm_ltk, hash, 16); 1527 memcpy(setup->sm_local_ltk, hash, 16); 1528 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1529 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1530 break; 1531 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1532 memcpy(setup->sm_local_dhkey_check, hash, 16); 1533 if (IS_RESPONDER(sm_conn->sm_role)){ 1534 // responder 1535 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1536 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1537 } else { 1538 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1539 } 1540 } else { 1541 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1542 } 1543 break; 1544 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1545 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1546 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1547 break; 1548 } 1549 if (IS_RESPONDER(sm_conn->sm_role)){ 1550 // responder 1551 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1552 } else { 1553 // initiator 1554 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1555 } 1556 break; 1557 case SM_SC_W4_CALCULATE_H6_ILK: 1558 memcpy(setup->sm_t, hash, 16); 1559 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1560 break; 1561 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1562 #ifdef ENABLE_CLASSIC 1563 reverse_128(hash, setup->sm_t); 1564 link_key_type = sm_conn->sm_connection_authenticated ? 1565 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1566 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1567 if (IS_RESPONDER(sm_conn->sm_role)){ 1568 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1569 } else { 1570 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1571 } 1572 #endif 1573 if (IS_RESPONDER(sm_conn->sm_role)){ 1574 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1575 } else { 1576 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1577 } 1578 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1579 sm_done_for_handle(sm_conn->sm_handle); 1580 break; 1581 default: 1582 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1583 break; 1584 } 1585 sm_run(); 1586 } 1587 1588 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){ 1589 const uint16_t message_len = 65; 1590 sm_cmac_connection = sm_conn; 1591 memcpy(sm_cmac_sc_buffer, u, 32); 1592 memcpy(sm_cmac_sc_buffer+32, v, 32); 1593 sm_cmac_sc_buffer[64] = z; 1594 log_info("f4 key"); 1595 log_info_hexdump(x, 16); 1596 log_info("f4 message"); 1597 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1598 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1599 } 1600 1601 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1602 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1603 static const uint8_t f5_length[] = { 0x01, 0x00}; 1604 1605 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1606 1607 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1608 memset(dhkey, 0, 32); 1609 1610 #ifdef USE_MICRO_ECC_FOR_ECDH 1611 #if uECC_SUPPORTS_secp256r1 1612 // standard version 1613 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1()); 1614 #else 1615 // static version 1616 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1617 #endif 1618 #endif 1619 1620 #ifdef USE_MBEDTLS_FOR_ECDH 1621 // da * Pb 1622 mbedtls_mpi d; 1623 mbedtls_ecp_point Q; 1624 mbedtls_ecp_point DH; 1625 mbedtls_mpi_init(&d); 1626 mbedtls_ecp_point_init(&Q); 1627 mbedtls_ecp_point_init(&DH); 1628 mbedtls_mpi_read_binary(&d, ec_d, 32); 1629 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); 1630 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 1631 mbedtls_mpi_lset(&Q.Z, 1); 1632 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1633 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1634 mbedtls_ecp_point_free(&DH); 1635 mbedtls_mpi_free(&d); 1636 mbedtls_ecp_point_free(&Q); 1637 #endif 1638 1639 log_info("dhkey"); 1640 log_info_hexdump(dhkey, 32); 1641 } 1642 #endif 1643 1644 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1645 // calculate salt for f5 1646 const uint16_t message_len = 32; 1647 sm_cmac_connection = sm_conn; 1648 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1649 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1650 } 1651 1652 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){ 1653 const uint16_t message_len = 53; 1654 sm_cmac_connection = sm_conn; 1655 1656 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1657 sm_cmac_sc_buffer[0] = 0; 1658 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1659 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1660 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1661 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1662 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1663 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1664 log_info("f5 key"); 1665 log_info_hexdump(t, 16); 1666 log_info("f5 message for MacKey"); 1667 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1668 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1669 } 1670 1671 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1672 sm_key56_t bd_addr_master, bd_addr_slave; 1673 bd_addr_master[0] = setup->sm_m_addr_type; 1674 bd_addr_slave[0] = setup->sm_s_addr_type; 1675 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1676 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1677 if (IS_RESPONDER(sm_conn->sm_role)){ 1678 // responder 1679 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1680 } else { 1681 // initiator 1682 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1683 } 1684 } 1685 1686 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1687 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1688 const uint16_t message_len = 53; 1689 sm_cmac_connection = sm_conn; 1690 sm_cmac_sc_buffer[0] = 1; 1691 // 1..52 setup before 1692 log_info("f5 key"); 1693 log_info_hexdump(t, 16); 1694 log_info("f5 message for LTK"); 1695 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1696 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1697 } 1698 1699 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1700 f5_ltk(sm_conn, setup->sm_t); 1701 } 1702 1703 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){ 1704 const uint16_t message_len = 65; 1705 sm_cmac_connection = sm_conn; 1706 memcpy(sm_cmac_sc_buffer, n1, 16); 1707 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1708 memcpy(sm_cmac_sc_buffer+32, r, 16); 1709 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1710 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1711 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1712 log_info("f6 key"); 1713 log_info_hexdump(w, 16); 1714 log_info("f6 message"); 1715 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1716 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1717 } 1718 1719 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1720 // - U is 256 bits 1721 // - V is 256 bits 1722 // - X is 128 bits 1723 // - Y is 128 bits 1724 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){ 1725 const uint16_t message_len = 80; 1726 sm_cmac_connection = sm_conn; 1727 memcpy(sm_cmac_sc_buffer, u, 32); 1728 memcpy(sm_cmac_sc_buffer+32, v, 32); 1729 memcpy(sm_cmac_sc_buffer+64, y, 16); 1730 log_info("g2 key"); 1731 log_info_hexdump(x, 16); 1732 log_info("g2 message"); 1733 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1734 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1735 } 1736 1737 static void g2_calculate(sm_connection_t * sm_conn) { 1738 // calc Va if numeric comparison 1739 if (IS_RESPONDER(sm_conn->sm_role)){ 1740 // responder 1741 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1742 } else { 1743 // initiator 1744 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1745 } 1746 } 1747 1748 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1749 uint8_t z = 0; 1750 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1751 // some form of passkey 1752 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1753 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1754 setup->sm_passkey_bit++; 1755 } 1756 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1757 } 1758 1759 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1760 uint8_t z = 0; 1761 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1762 // some form of passkey 1763 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1764 // sm_passkey_bit was increased before sending confirm value 1765 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1766 } 1767 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1768 } 1769 1770 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1771 1772 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1773 // calculate DHKEY 1774 sm_sc_calculate_dhkey(setup->sm_dhkey); 1775 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1776 #endif 1777 1778 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1779 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1780 return; 1781 } else { 1782 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1783 } 1784 1785 } 1786 1787 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1788 // calculate DHKCheck 1789 sm_key56_t bd_addr_master, bd_addr_slave; 1790 bd_addr_master[0] = setup->sm_m_addr_type; 1791 bd_addr_slave[0] = setup->sm_s_addr_type; 1792 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1793 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1794 uint8_t iocap_a[3]; 1795 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1796 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1797 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1798 uint8_t iocap_b[3]; 1799 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1800 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1801 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1802 if (IS_RESPONDER(sm_conn->sm_role)){ 1803 // responder 1804 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); 1805 } else { 1806 // initiator 1807 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); 1808 } 1809 } 1810 1811 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1812 // validate E = f6() 1813 sm_key56_t bd_addr_master, bd_addr_slave; 1814 bd_addr_master[0] = setup->sm_m_addr_type; 1815 bd_addr_slave[0] = setup->sm_s_addr_type; 1816 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1817 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1818 1819 uint8_t iocap_a[3]; 1820 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1821 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1822 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1823 uint8_t iocap_b[3]; 1824 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1825 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1826 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1827 if (IS_RESPONDER(sm_conn->sm_role)){ 1828 // responder 1829 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); 1830 } else { 1831 // initiator 1832 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); 1833 } 1834 } 1835 1836 1837 // 1838 // Link Key Conversion Function h6 1839 // 1840 // h6(W, keyID) = AES-CMACW(keyID) 1841 // - W is 128 bits 1842 // - keyID is 32 bits 1843 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1844 const uint16_t message_len = 4; 1845 sm_cmac_connection = sm_conn; 1846 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1847 log_info("h6 key"); 1848 log_info_hexdump(w, 16); 1849 log_info("h6 message"); 1850 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1851 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1852 } 1853 1854 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1855 // Errata Service Release to the Bluetooth Specification: ESR09 1856 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1857 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1858 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1859 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1860 } 1861 1862 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1863 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1864 } 1865 1866 #endif 1867 1868 // key management legacy connections: 1869 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1870 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1871 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1872 // - responder reconnects: responder uses LTK receveived from master 1873 1874 // key management secure connections: 1875 // - both devices store same LTK from ECDH key exchange. 1876 1877 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1878 static void sm_load_security_info(sm_connection_t * sm_connection){ 1879 int encryption_key_size; 1880 int authenticated; 1881 int authorized; 1882 1883 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1884 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1885 &encryption_key_size, &authenticated, &authorized); 1886 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1887 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1888 sm_connection->sm_connection_authenticated = authenticated; 1889 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1890 } 1891 #endif 1892 1893 #ifdef ENABLE_LE_PERIPHERAL 1894 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1895 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1896 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1897 // re-establish used key encryption size 1898 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1899 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1900 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1901 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1902 log_info("sm: received ltk request with key size %u, authenticated %u", 1903 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1904 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1905 } 1906 #endif 1907 1908 static void sm_run(void){ 1909 1910 btstack_linked_list_iterator_t it; 1911 1912 // assert that stack has already bootet 1913 if (hci_get_state() != HCI_STATE_WORKING) return; 1914 1915 // assert that we can send at least commands 1916 if (!hci_can_send_command_packet_now()) return; 1917 1918 // 1919 // non-connection related behaviour 1920 // 1921 1922 // distributed key generation 1923 switch (dkg_state){ 1924 case DKG_CALC_IRK: 1925 // already busy? 1926 if (sm_aes128_state == SM_AES128_IDLE) { 1927 // IRK = d1(IR, 1, 0) 1928 sm_key_t d1_prime; 1929 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1930 dkg_next_state(); 1931 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1932 return; 1933 } 1934 break; 1935 case DKG_CALC_DHK: 1936 // already busy? 1937 if (sm_aes128_state == SM_AES128_IDLE) { 1938 // DHK = d1(IR, 3, 0) 1939 sm_key_t d1_prime; 1940 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1941 dkg_next_state(); 1942 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1943 return; 1944 } 1945 break; 1946 default: 1947 break; 1948 } 1949 1950 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1951 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1952 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1953 sm_random_start(NULL); 1954 #else 1955 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1956 hci_send_cmd(&hci_le_read_local_p256_public_key); 1957 #endif 1958 return; 1959 } 1960 #endif 1961 1962 // random address updates 1963 switch (rau_state){ 1964 case RAU_GET_RANDOM: 1965 rau_next_state(); 1966 sm_random_start(NULL); 1967 return; 1968 case RAU_GET_ENC: 1969 // already busy? 1970 if (sm_aes128_state == SM_AES128_IDLE) { 1971 sm_key_t r_prime; 1972 sm_ah_r_prime(sm_random_address, r_prime); 1973 rau_next_state(); 1974 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1975 return; 1976 } 1977 break; 1978 case RAU_SET_ADDRESS: 1979 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1980 rau_state = RAU_IDLE; 1981 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1982 return; 1983 default: 1984 break; 1985 } 1986 1987 #ifdef ENABLE_CMAC_ENGINE 1988 // CMAC 1989 switch (sm_cmac_state){ 1990 case CMAC_CALC_SUBKEYS: 1991 case CMAC_CALC_MI: 1992 case CMAC_CALC_MLAST: 1993 // already busy? 1994 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1995 sm_cmac_handle_aes_engine_ready(); 1996 return; 1997 default: 1998 break; 1999 } 2000 #endif 2001 2002 // CSRK Lookup 2003 // -- if csrk lookup ready, find connection that require csrk lookup 2004 if (sm_address_resolution_idle()){ 2005 hci_connections_get_iterator(&it); 2006 while(btstack_linked_list_iterator_has_next(&it)){ 2007 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2008 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2009 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2010 // and start lookup 2011 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); 2012 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2013 break; 2014 } 2015 } 2016 } 2017 2018 // -- if csrk lookup ready, resolved addresses for received addresses 2019 if (sm_address_resolution_idle()) { 2020 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2021 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2022 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2023 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2024 btstack_memory_sm_lookup_entry_free(entry); 2025 } 2026 } 2027 2028 // -- Continue with CSRK device lookup by public or resolvable private address 2029 if (!sm_address_resolution_idle()){ 2030 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2031 while (sm_address_resolution_test < le_device_db_max_count()){ 2032 int addr_type; 2033 bd_addr_t addr; 2034 sm_key_t irk; 2035 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2036 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2037 2038 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 2039 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2040 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2041 break; 2042 } 2043 2044 if (sm_address_resolution_addr_type == 0){ 2045 sm_address_resolution_test++; 2046 continue; 2047 } 2048 2049 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2050 2051 log_info("LE Device Lookup: calculate AH"); 2052 log_info_key("IRK", irk); 2053 2054 sm_key_t r_prime; 2055 sm_ah_r_prime(sm_address_resolution_address, r_prime); 2056 sm_address_resolution_ah_calculation_active = 1; 2057 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 2058 return; 2059 } 2060 2061 if (sm_address_resolution_test >= le_device_db_max_count()){ 2062 log_info("LE Device Lookup: not found"); 2063 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2064 } 2065 } 2066 2067 // handle basic actions that don't requires the full context 2068 hci_connections_get_iterator(&it); 2069 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2070 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2071 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2072 switch(sm_connection->sm_engine_state){ 2073 // responder side 2074 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2075 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2076 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2077 return; 2078 2079 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2080 case SM_SC_RECEIVED_LTK_REQUEST: 2081 switch (sm_connection->sm_irk_lookup_state){ 2082 case IRK_LOOKUP_FAILED: 2083 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2084 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2085 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2086 return; 2087 default: 2088 break; 2089 } 2090 break; 2091 #endif 2092 default: 2093 break; 2094 } 2095 } 2096 2097 // 2098 // active connection handling 2099 // -- use loop to handle next connection if lock on setup context is released 2100 2101 while (1) { 2102 2103 // Find connections that requires setup context and make active if no other is locked 2104 hci_connections_get_iterator(&it); 2105 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2106 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2107 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2108 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2109 int done = 1; 2110 int err; 2111 UNUSED(err); 2112 switch (sm_connection->sm_engine_state) { 2113 #ifdef ENABLE_LE_PERIPHERAL 2114 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2115 // send packet if possible, 2116 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2117 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2118 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2119 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2120 } else { 2121 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2122 } 2123 // don't lock sxetup context yet 2124 done = 0; 2125 break; 2126 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2127 sm_reset_setup(); 2128 sm_init_setup(sm_connection); 2129 // recover pairing request 2130 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2131 err = sm_stk_generation_init(sm_connection); 2132 2133 #ifdef ENABLE_TESTING_SUPPORT 2134 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2135 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2136 err = test_pairing_failure; 2137 } 2138 #endif 2139 if (err){ 2140 setup->sm_pairing_failed_reason = err; 2141 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2142 break; 2143 } 2144 sm_timeout_start(sm_connection); 2145 // generate random number first, if we need to show passkey 2146 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2147 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2148 break; 2149 } 2150 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2151 break; 2152 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2153 sm_reset_setup(); 2154 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2155 break; 2156 #endif 2157 #ifdef ENABLE_LE_CENTRAL 2158 case SM_INITIATOR_PH0_HAS_LTK: 2159 sm_reset_setup(); 2160 sm_load_security_info(sm_connection); 2161 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2162 break; 2163 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2164 sm_reset_setup(); 2165 sm_init_setup(sm_connection); 2166 sm_timeout_start(sm_connection); 2167 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2168 break; 2169 #endif 2170 2171 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2172 case SM_SC_RECEIVED_LTK_REQUEST: 2173 switch (sm_connection->sm_irk_lookup_state){ 2174 case IRK_LOOKUP_SUCCEEDED: 2175 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2176 // start using context by loading security info 2177 sm_reset_setup(); 2178 sm_load_security_info(sm_connection); 2179 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2180 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2181 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2182 break; 2183 } 2184 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2185 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2186 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2187 // don't lock setup context yet 2188 return; 2189 default: 2190 // just wait until IRK lookup is completed 2191 // don't lock setup context yet 2192 done = 0; 2193 break; 2194 } 2195 break; 2196 #endif 2197 default: 2198 done = 0; 2199 break; 2200 } 2201 if (done){ 2202 sm_active_connection_handle = sm_connection->sm_handle; 2203 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); 2204 } 2205 } 2206 2207 // 2208 // active connection handling 2209 // 2210 2211 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2212 2213 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2214 if (!connection) { 2215 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2216 return; 2217 } 2218 2219 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2220 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_NEEDED){ 2221 setup->sm_state_vars &= ~SM_STATE_VAR_DHKEY_NEEDED; 2222 hci_send_cmd(&hci_le_generate_dhkey, &setup->sm_peer_q[0], &setup->sm_peer_q[32]); 2223 return; 2224 } 2225 #endif 2226 2227 // assert that we could send a SM PDU - not needed for all of the following 2228 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2229 log_info("cannot send now, requesting can send now event"); 2230 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2231 return; 2232 } 2233 2234 // send keypress notifications 2235 if (setup->sm_keypress_notification){ 2236 int i; 2237 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2238 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2239 uint8_t action = 0; 2240 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2241 if (flags & (1<<i)){ 2242 int clear_flag = 1; 2243 switch (i){ 2244 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2245 case SM_KEYPRESS_PASSKEY_CLEARED: 2246 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2247 default: 2248 break; 2249 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2250 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2251 num_actions--; 2252 clear_flag = num_actions == 0; 2253 break; 2254 } 2255 if (clear_flag){ 2256 flags &= ~(1<<i); 2257 } 2258 action = i; 2259 break; 2260 } 2261 } 2262 setup->sm_keypress_notification = (num_actions << 5) | flags; 2263 2264 // send keypress notification 2265 uint8_t buffer[2]; 2266 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2267 buffer[1] = action; 2268 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2269 2270 // try 2271 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2272 return; 2273 } 2274 2275 sm_key_t plaintext; 2276 int key_distribution_flags; 2277 UNUSED(key_distribution_flags); 2278 2279 log_info("sm_run: state %u", connection->sm_engine_state); 2280 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2281 log_info("sm_run // cannot send"); 2282 } 2283 switch (connection->sm_engine_state){ 2284 2285 // general 2286 case SM_GENERAL_SEND_PAIRING_FAILED: { 2287 uint8_t buffer[2]; 2288 buffer[0] = SM_CODE_PAIRING_FAILED; 2289 buffer[1] = setup->sm_pairing_failed_reason; 2290 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2291 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2292 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2293 sm_done_for_handle(connection->sm_handle); 2294 break; 2295 } 2296 2297 // responding state 2298 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2299 case SM_SC_W2_GET_RANDOM_A: 2300 sm_random_start(connection); 2301 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2302 break; 2303 case SM_SC_W2_GET_RANDOM_B: 2304 sm_random_start(connection); 2305 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2306 break; 2307 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2308 if (!sm_cmac_ready()) break; 2309 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2310 sm_sc_calculate_local_confirm(connection); 2311 break; 2312 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2313 if (!sm_cmac_ready()) break; 2314 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2315 sm_sc_calculate_remote_confirm(connection); 2316 break; 2317 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2318 if (!sm_cmac_ready()) break; 2319 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2320 sm_sc_calculate_f6_for_dhkey_check(connection); 2321 break; 2322 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2323 if (!sm_cmac_ready()) break; 2324 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2325 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2326 break; 2327 case SM_SC_W2_CALCULATE_F5_SALT: 2328 if (!sm_cmac_ready()) break; 2329 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2330 f5_calculate_salt(connection); 2331 break; 2332 case SM_SC_W2_CALCULATE_F5_MACKEY: 2333 if (!sm_cmac_ready()) break; 2334 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2335 f5_calculate_mackey(connection); 2336 break; 2337 case SM_SC_W2_CALCULATE_F5_LTK: 2338 if (!sm_cmac_ready()) break; 2339 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2340 f5_calculate_ltk(connection); 2341 break; 2342 case SM_SC_W2_CALCULATE_G2: 2343 if (!sm_cmac_ready()) break; 2344 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2345 g2_calculate(connection); 2346 break; 2347 case SM_SC_W2_CALCULATE_H6_ILK: 2348 if (!sm_cmac_ready()) break; 2349 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2350 h6_calculate_ilk(connection); 2351 break; 2352 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2353 if (!sm_cmac_ready()) break; 2354 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2355 h6_calculate_br_edr_link_key(connection); 2356 break; 2357 #endif 2358 2359 #ifdef ENABLE_LE_CENTRAL 2360 // initiator side 2361 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2362 sm_key_t peer_ltk_flipped; 2363 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2364 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2365 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2366 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2367 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2368 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2369 return; 2370 } 2371 2372 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2373 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2374 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2375 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2376 sm_timeout_reset(connection); 2377 break; 2378 #endif 2379 2380 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2381 2382 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2383 int trigger_user_response = 0; 2384 2385 uint8_t buffer[65]; 2386 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2387 // 2388 reverse_256(&ec_q[0], &buffer[1]); 2389 reverse_256(&ec_q[32], &buffer[33]); 2390 2391 // stk generation method 2392 // passkey entry: notify app to show passkey or to request passkey 2393 switch (setup->sm_stk_generation_method){ 2394 case JUST_WORKS: 2395 case NK_BOTH_INPUT: 2396 if (IS_RESPONDER(connection->sm_role)){ 2397 // responder 2398 sm_sc_start_calculating_local_confirm(connection); 2399 } else { 2400 // initiator 2401 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2402 } 2403 break; 2404 case PK_INIT_INPUT: 2405 case PK_RESP_INPUT: 2406 case OK_BOTH_INPUT: 2407 // use random TK for display 2408 memcpy(setup->sm_ra, setup->sm_tk, 16); 2409 memcpy(setup->sm_rb, setup->sm_tk, 16); 2410 setup->sm_passkey_bit = 0; 2411 2412 if (IS_RESPONDER(connection->sm_role)){ 2413 // responder 2414 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2415 } else { 2416 // initiator 2417 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2418 } 2419 trigger_user_response = 1; 2420 break; 2421 case OOB: 2422 if (IS_RESPONDER(connection->sm_role)){ 2423 // responder 2424 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2425 } else { 2426 // initiator 2427 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2428 } 2429 break; 2430 } 2431 2432 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2433 sm_timeout_reset(connection); 2434 2435 // trigger user response after sending pdu 2436 if (trigger_user_response){ 2437 sm_trigger_user_response(connection); 2438 } 2439 break; 2440 } 2441 case SM_SC_SEND_CONFIRMATION: { 2442 uint8_t buffer[17]; 2443 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2444 reverse_128(setup->sm_local_confirm, &buffer[1]); 2445 if (IS_RESPONDER(connection->sm_role)){ 2446 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2447 } else { 2448 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2449 } 2450 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2451 sm_timeout_reset(connection); 2452 break; 2453 } 2454 case SM_SC_SEND_PAIRING_RANDOM: { 2455 uint8_t buffer[17]; 2456 buffer[0] = SM_CODE_PAIRING_RANDOM; 2457 reverse_128(setup->sm_local_nonce, &buffer[1]); 2458 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2459 if (IS_RESPONDER(connection->sm_role)){ 2460 // responder 2461 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2462 } else { 2463 // initiator 2464 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2465 } 2466 } else { 2467 if (IS_RESPONDER(connection->sm_role)){ 2468 // responder 2469 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2470 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2471 } else { 2472 sm_sc_prepare_dhkey_check(connection); 2473 } 2474 } else { 2475 // initiator 2476 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2477 } 2478 } 2479 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2480 sm_timeout_reset(connection); 2481 break; 2482 } 2483 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2484 uint8_t buffer[17]; 2485 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2486 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2487 2488 if (IS_RESPONDER(connection->sm_role)){ 2489 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2490 } else { 2491 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2492 } 2493 2494 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2495 sm_timeout_reset(connection); 2496 break; 2497 } 2498 2499 #endif 2500 2501 #ifdef ENABLE_LE_PERIPHERAL 2502 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2503 // echo initiator for now 2504 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2505 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2506 2507 if (setup->sm_use_secure_connections){ 2508 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2509 // skip LTK/EDIV for SC 2510 log_info("sm: dropping encryption information flag"); 2511 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2512 } else { 2513 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2514 } 2515 2516 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); 2517 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); 2518 // update key distribution after ENC was dropped 2519 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2520 2521 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2522 sm_timeout_reset(connection); 2523 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2524 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2525 sm_trigger_user_response(connection); 2526 } 2527 return; 2528 #endif 2529 2530 case SM_PH2_SEND_PAIRING_RANDOM: { 2531 uint8_t buffer[17]; 2532 buffer[0] = SM_CODE_PAIRING_RANDOM; 2533 reverse_128(setup->sm_local_random, &buffer[1]); 2534 if (IS_RESPONDER(connection->sm_role)){ 2535 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2536 } else { 2537 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2538 } 2539 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2540 sm_timeout_reset(connection); 2541 break; 2542 } 2543 2544 case SM_PH2_GET_RANDOM_TK: 2545 case SM_PH2_C1_GET_RANDOM_A: 2546 case SM_PH2_C1_GET_RANDOM_B: 2547 case SM_PH3_GET_RANDOM: 2548 case SM_PH3_GET_DIV: 2549 sm_next_responding_state(connection); 2550 sm_random_start(connection); 2551 return; 2552 2553 case SM_PH2_C1_GET_ENC_B: 2554 case SM_PH2_C1_GET_ENC_D: 2555 // already busy? 2556 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2557 sm_next_responding_state(connection); 2558 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2559 return; 2560 2561 case SM_PH3_LTK_GET_ENC: 2562 case SM_RESPONDER_PH4_LTK_GET_ENC: 2563 // already busy? 2564 if (sm_aes128_state == SM_AES128_IDLE) { 2565 sm_key_t d_prime; 2566 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2567 sm_next_responding_state(connection); 2568 sm_aes128_start(sm_persistent_er, d_prime, connection); 2569 return; 2570 } 2571 break; 2572 2573 case SM_PH3_CSRK_GET_ENC: 2574 // already busy? 2575 if (sm_aes128_state == SM_AES128_IDLE) { 2576 sm_key_t d_prime; 2577 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2578 sm_next_responding_state(connection); 2579 sm_aes128_start(sm_persistent_er, d_prime, connection); 2580 return; 2581 } 2582 break; 2583 2584 case SM_PH2_C1_GET_ENC_C: 2585 // already busy? 2586 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2587 // calculate m_confirm using aes128 engine - step 1 2588 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); 2589 sm_next_responding_state(connection); 2590 sm_aes128_start(setup->sm_tk, plaintext, connection); 2591 break; 2592 case SM_PH2_C1_GET_ENC_A: 2593 // already busy? 2594 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2595 // calculate confirm using aes128 engine - step 1 2596 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); 2597 sm_next_responding_state(connection); 2598 sm_aes128_start(setup->sm_tk, plaintext, connection); 2599 break; 2600 case SM_PH2_CALC_STK: 2601 // already busy? 2602 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2603 // calculate STK 2604 if (IS_RESPONDER(connection->sm_role)){ 2605 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2606 } else { 2607 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2608 } 2609 sm_next_responding_state(connection); 2610 sm_aes128_start(setup->sm_tk, plaintext, connection); 2611 break; 2612 case SM_PH3_Y_GET_ENC: 2613 // already busy? 2614 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2615 // PH3B2 - calculate Y from - enc 2616 // Y = dm(DHK, Rand) 2617 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2618 sm_next_responding_state(connection); 2619 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2620 return; 2621 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2622 uint8_t buffer[17]; 2623 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2624 reverse_128(setup->sm_local_confirm, &buffer[1]); 2625 if (IS_RESPONDER(connection->sm_role)){ 2626 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2627 } else { 2628 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2629 } 2630 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2631 sm_timeout_reset(connection); 2632 return; 2633 } 2634 #ifdef ENABLE_LE_PERIPHERAL 2635 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2636 sm_key_t stk_flipped; 2637 reverse_128(setup->sm_ltk, stk_flipped); 2638 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2639 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2640 return; 2641 } 2642 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2643 sm_key_t ltk_flipped; 2644 reverse_128(setup->sm_ltk, ltk_flipped); 2645 connection->sm_engine_state = SM_RESPONDER_IDLE; 2646 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2647 sm_done_for_handle(connection->sm_handle); 2648 return; 2649 } 2650 case SM_RESPONDER_PH4_Y_GET_ENC: 2651 // already busy? 2652 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2653 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2654 // Y = dm(DHK, Rand) 2655 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2656 sm_next_responding_state(connection); 2657 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2658 return; 2659 #endif 2660 #ifdef ENABLE_LE_CENTRAL 2661 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2662 sm_key_t stk_flipped; 2663 reverse_128(setup->sm_ltk, stk_flipped); 2664 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2665 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2666 return; 2667 } 2668 #endif 2669 2670 case SM_PH3_DISTRIBUTE_KEYS: 2671 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2672 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2673 uint8_t buffer[17]; 2674 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2675 reverse_128(setup->sm_ltk, &buffer[1]); 2676 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2677 sm_timeout_reset(connection); 2678 return; 2679 } 2680 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2681 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2682 uint8_t buffer[11]; 2683 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2684 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2685 reverse_64(setup->sm_local_rand, &buffer[3]); 2686 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2687 sm_timeout_reset(connection); 2688 return; 2689 } 2690 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2691 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2692 uint8_t buffer[17]; 2693 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2694 reverse_128(sm_persistent_irk, &buffer[1]); 2695 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2696 sm_timeout_reset(connection); 2697 return; 2698 } 2699 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2700 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2701 bd_addr_t local_address; 2702 uint8_t buffer[8]; 2703 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2704 switch (gap_random_address_get_mode()){ 2705 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2706 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2707 // public or static random 2708 gap_le_get_own_address(&buffer[1], local_address); 2709 break; 2710 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2711 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2712 // fallback to public 2713 gap_local_bd_addr(local_address); 2714 buffer[1] = 0; 2715 break; 2716 } 2717 reverse_bd_addr(local_address, &buffer[2]); 2718 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2719 sm_timeout_reset(connection); 2720 return; 2721 } 2722 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2723 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2724 2725 // hack to reproduce test runs 2726 if (test_use_fixed_local_csrk){ 2727 memset(setup->sm_local_csrk, 0xcc, 16); 2728 } 2729 2730 uint8_t buffer[17]; 2731 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2732 reverse_128(setup->sm_local_csrk, &buffer[1]); 2733 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2734 sm_timeout_reset(connection); 2735 return; 2736 } 2737 2738 // keys are sent 2739 if (IS_RESPONDER(connection->sm_role)){ 2740 // slave -> receive master keys if any 2741 if (sm_key_distribution_all_received(connection)){ 2742 sm_key_distribution_handle_all_received(connection); 2743 connection->sm_engine_state = SM_RESPONDER_IDLE; 2744 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2745 sm_done_for_handle(connection->sm_handle); 2746 } else { 2747 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2748 } 2749 } else { 2750 // master -> all done 2751 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2752 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2753 sm_done_for_handle(connection->sm_handle); 2754 } 2755 break; 2756 2757 default: 2758 break; 2759 } 2760 2761 // check again if active connection was released 2762 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2763 } 2764 } 2765 2766 // note: aes engine is ready as we just got the aes result 2767 static void sm_handle_encryption_result(uint8_t * data){ 2768 2769 sm_aes128_state = SM_AES128_IDLE; 2770 2771 if (sm_address_resolution_ah_calculation_active){ 2772 sm_address_resolution_ah_calculation_active = 0; 2773 // compare calulated address against connecting device 2774 uint8_t hash[3]; 2775 reverse_24(data, hash); 2776 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2777 log_info("LE Device Lookup: matched resolvable private address"); 2778 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2779 return; 2780 } 2781 // no match, try next 2782 sm_address_resolution_test++; 2783 return; 2784 } 2785 2786 switch (dkg_state){ 2787 case DKG_W4_IRK: 2788 reverse_128(data, sm_persistent_irk); 2789 log_info_key("irk", sm_persistent_irk); 2790 dkg_next_state(); 2791 return; 2792 case DKG_W4_DHK: 2793 reverse_128(data, sm_persistent_dhk); 2794 log_info_key("dhk", sm_persistent_dhk); 2795 dkg_next_state(); 2796 // SM Init Finished 2797 return; 2798 default: 2799 break; 2800 } 2801 2802 switch (rau_state){ 2803 case RAU_W4_ENC: 2804 reverse_24(data, &sm_random_address[3]); 2805 rau_next_state(); 2806 return; 2807 default: 2808 break; 2809 } 2810 2811 #ifdef ENABLE_CMAC_ENGINE 2812 switch (sm_cmac_state){ 2813 case CMAC_W4_SUBKEYS: 2814 case CMAC_W4_MI: 2815 case CMAC_W4_MLAST: 2816 { 2817 sm_key_t t; 2818 reverse_128(data, t); 2819 sm_cmac_handle_encryption_result(t); 2820 } 2821 return; 2822 default: 2823 break; 2824 } 2825 #endif 2826 2827 // retrieve sm_connection provided to sm_aes128_start_encryption 2828 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2829 if (!connection) return; 2830 switch (connection->sm_engine_state){ 2831 case SM_PH2_C1_W4_ENC_A: 2832 case SM_PH2_C1_W4_ENC_C: 2833 { 2834 sm_key_t t2; 2835 reverse_128(data, t2); 2836 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2837 } 2838 sm_next_responding_state(connection); 2839 return; 2840 case SM_PH2_C1_W4_ENC_B: 2841 reverse_128(data, setup->sm_local_confirm); 2842 log_info_key("c1!", setup->sm_local_confirm); 2843 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2844 return; 2845 case SM_PH2_C1_W4_ENC_D: 2846 { 2847 sm_key_t peer_confirm_test; 2848 reverse_128(data, peer_confirm_test); 2849 log_info_key("c1!", peer_confirm_test); 2850 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2851 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2852 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2853 return; 2854 } 2855 if (IS_RESPONDER(connection->sm_role)){ 2856 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2857 } else { 2858 connection->sm_engine_state = SM_PH2_CALC_STK; 2859 } 2860 } 2861 return; 2862 case SM_PH2_W4_STK: 2863 reverse_128(data, setup->sm_ltk); 2864 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2865 log_info_key("stk", setup->sm_ltk); 2866 if (IS_RESPONDER(connection->sm_role)){ 2867 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2868 } else { 2869 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2870 } 2871 return; 2872 case SM_PH3_Y_W4_ENC:{ 2873 sm_key_t y128; 2874 reverse_128(data, y128); 2875 setup->sm_local_y = big_endian_read_16(y128, 14); 2876 log_info_hex16("y", setup->sm_local_y); 2877 // PH3B3 - calculate EDIV 2878 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2879 log_info_hex16("ediv", setup->sm_local_ediv); 2880 // PH3B4 - calculate LTK - enc 2881 // LTK = d1(ER, DIV, 0)) 2882 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2883 return; 2884 } 2885 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2886 sm_key_t y128; 2887 reverse_128(data, y128); 2888 setup->sm_local_y = big_endian_read_16(y128, 14); 2889 log_info_hex16("y", setup->sm_local_y); 2890 2891 // PH3B3 - calculate DIV 2892 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2893 log_info_hex16("ediv", setup->sm_local_ediv); 2894 // PH3B4 - calculate LTK - enc 2895 // LTK = d1(ER, DIV, 0)) 2896 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2897 return; 2898 } 2899 case SM_PH3_LTK_W4_ENC: 2900 reverse_128(data, setup->sm_ltk); 2901 log_info_key("ltk", setup->sm_ltk); 2902 // calc CSRK next 2903 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2904 return; 2905 case SM_PH3_CSRK_W4_ENC: 2906 reverse_128(data, setup->sm_local_csrk); 2907 log_info_key("csrk", setup->sm_local_csrk); 2908 if (setup->sm_key_distribution_send_set){ 2909 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2910 } else { 2911 // no keys to send, just continue 2912 if (IS_RESPONDER(connection->sm_role)){ 2913 // slave -> receive master keys 2914 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2915 } else { 2916 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2917 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2918 } else { 2919 // master -> all done 2920 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2921 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2922 sm_done_for_handle(connection->sm_handle); 2923 } 2924 } 2925 } 2926 return; 2927 #ifdef ENABLE_LE_PERIPHERAL 2928 case SM_RESPONDER_PH4_LTK_W4_ENC: 2929 reverse_128(data, setup->sm_ltk); 2930 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2931 log_info_key("ltk", setup->sm_ltk); 2932 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2933 return; 2934 #endif 2935 default: 2936 break; 2937 } 2938 } 2939 2940 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2941 2942 #if (defined(USE_MICRO_ECC_FOR_ECDH) && !defined(WICED_VERSION)) || defined(USE_MBEDTLS_FOR_ECDH) 2943 // @return OK 2944 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2945 if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; 2946 int offset = setup->sm_passkey_bit; 2947 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2948 while (size) { 2949 *buffer++ = setup->sm_peer_q[offset++]; 2950 size--; 2951 } 2952 setup->sm_passkey_bit = offset; 2953 return 1; 2954 } 2955 #endif 2956 #ifdef USE_MBEDTLS_FOR_ECDH 2957 // @return error - just wrap sm_generate_f_rng 2958 static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ 2959 UNUSED(context); 2960 return sm_generate_f_rng(buffer, size) == 0; 2961 } 2962 #endif /* USE_MBEDTLS_FOR_ECDH */ 2963 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2964 2965 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2966 static void sm_handle_random_result(uint8_t * data){ 2967 2968 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2969 2970 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2971 int num_bytes = setup->sm_passkey_bit; 2972 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 2973 num_bytes += 8; 2974 setup->sm_passkey_bit = num_bytes; 2975 2976 if (num_bytes >= 64){ 2977 2978 // init pre-generated random data from sm_peer_q 2979 setup->sm_passkey_bit = 0; 2980 2981 // generate EC key 2982 #ifdef USE_MICRO_ECC_FOR_ECDH 2983 2984 #ifndef WICED_VERSION 2985 log_info("set uECC RNG for initial key generation with 64 random bytes"); 2986 // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it 2987 uECC_set_rng(&sm_generate_f_rng); 2988 #endif /* WICED_VERSION */ 2989 2990 #if uECC_SUPPORTS_secp256r1 2991 // standard version 2992 uECC_make_key(ec_q, ec_d, uECC_secp256r1()); 2993 2994 // disable RNG again, as returning no randmon data lets shared key generation fail 2995 log_info("disable uECC RNG in standard version after key generation"); 2996 uECC_set_rng(NULL); 2997 #else 2998 // static version 2999 uECC_make_key(ec_q, ec_d); 3000 #endif 3001 #endif /* USE_MICRO_ECC_FOR_ECDH */ 3002 3003 #ifdef USE_MBEDTLS_FOR_ECDH 3004 mbedtls_mpi d; 3005 mbedtls_ecp_point P; 3006 mbedtls_mpi_init(&d); 3007 mbedtls_ecp_point_init(&P); 3008 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); 3009 log_info("gen keypair %x", res); 3010 mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); 3011 mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); 3012 mbedtls_mpi_write_binary(&d, ec_d, 32); 3013 mbedtls_ecp_point_free(&P); 3014 mbedtls_mpi_free(&d); 3015 #endif /* USE_MBEDTLS_FOR_ECDH */ 3016 3017 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3018 log_info("Elliptic curve: d"); 3019 log_info_hexdump(ec_d,32); 3020 sm_log_ec_keypair(); 3021 } 3022 } 3023 #endif 3024 3025 switch (rau_state){ 3026 case RAU_W4_RANDOM: 3027 // non-resolvable vs. resolvable 3028 switch (gap_random_adress_type){ 3029 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3030 // resolvable: use random as prand and calc address hash 3031 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3032 memcpy(sm_random_address, data, 3); 3033 sm_random_address[0] &= 0x3f; 3034 sm_random_address[0] |= 0x40; 3035 rau_state = RAU_GET_ENC; 3036 break; 3037 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3038 default: 3039 // "The two most significant bits of the address shall be equal to ‘0’"" 3040 memcpy(sm_random_address, data, 6); 3041 sm_random_address[0] &= 0x3f; 3042 rau_state = RAU_SET_ADDRESS; 3043 break; 3044 } 3045 return; 3046 default: 3047 break; 3048 } 3049 3050 // retrieve sm_connection provided to sm_random_start 3051 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 3052 if (!connection) return; 3053 switch (connection->sm_engine_state){ 3054 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3055 case SM_SC_W4_GET_RANDOM_A: 3056 memcpy(&setup->sm_local_nonce[0], data, 8); 3057 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 3058 break; 3059 case SM_SC_W4_GET_RANDOM_B: 3060 memcpy(&setup->sm_local_nonce[8], data, 8); 3061 // OOB 3062 if (setup->sm_stk_generation_method == OOB){ 3063 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3064 break; 3065 } 3066 // initiator & jw/nc -> send pairing random 3067 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3068 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3069 break; 3070 } else { 3071 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3072 } 3073 break; 3074 #endif 3075 3076 case SM_PH2_W4_RANDOM_TK: 3077 { 3078 sm_reset_tk(); 3079 uint32_t tk; 3080 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3081 // map random to 0-999999 without speding much cycles on a modulus operation 3082 tk = little_endian_read_32(data,0); 3083 tk = tk & 0xfffff; // 1048575 3084 if (tk >= 999999){ 3085 tk = tk - 999999; 3086 } 3087 } else { 3088 // override with pre-defined passkey 3089 tk = sm_fixed_passkey_in_display_role; 3090 } 3091 big_endian_store_32(setup->sm_tk, 12, tk); 3092 if (IS_RESPONDER(connection->sm_role)){ 3093 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3094 } else { 3095 if (setup->sm_use_secure_connections){ 3096 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3097 } else { 3098 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3099 sm_trigger_user_response(connection); 3100 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3101 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3102 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3103 } 3104 } 3105 } 3106 return; 3107 } 3108 case SM_PH2_C1_W4_RANDOM_A: 3109 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 3110 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 3111 return; 3112 case SM_PH2_C1_W4_RANDOM_B: 3113 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 3114 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3115 return; 3116 case SM_PH3_W4_RANDOM: 3117 reverse_64(data, setup->sm_local_rand); 3118 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3119 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 3120 // no db for authenticated flag hack: store flag in bit 4 of LSB 3121 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 3122 connection->sm_engine_state = SM_PH3_GET_DIV; 3123 return; 3124 case SM_PH3_W4_DIV: 3125 // use 16 bit from random value as div 3126 setup->sm_local_div = big_endian_read_16(data, 0); 3127 log_info_hex16("div", setup->sm_local_div); 3128 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3129 return; 3130 default: 3131 break; 3132 } 3133 } 3134 3135 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3136 3137 UNUSED(channel); // ok: there is no channel 3138 UNUSED(size); // ok: fixed format HCI events 3139 3140 sm_connection_t * sm_conn; 3141 hci_con_handle_t con_handle; 3142 3143 switch (packet_type) { 3144 3145 case HCI_EVENT_PACKET: 3146 switch (hci_event_packet_get_type(packet)) { 3147 3148 case BTSTACK_EVENT_STATE: 3149 // bt stack activated, get started 3150 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3151 log_info("HCI Working!"); 3152 3153 3154 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 3155 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3156 if (!sm_have_ec_keypair){ 3157 setup->sm_passkey_bit = 0; 3158 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3159 } 3160 #endif 3161 // trigger Random Address generation if requested before 3162 switch (gap_random_adress_type){ 3163 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3164 rau_state = RAU_IDLE; 3165 break; 3166 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 3167 rau_state = RAU_SET_ADDRESS; 3168 break; 3169 default: 3170 rau_state = RAU_GET_RANDOM; 3171 break; 3172 } 3173 sm_run(); 3174 } 3175 break; 3176 3177 case HCI_EVENT_LE_META: 3178 switch (packet[2]) { 3179 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3180 3181 log_info("sm: connected"); 3182 3183 if (packet[3]) return; // connection failed 3184 3185 con_handle = little_endian_read_16(packet, 4); 3186 sm_conn = sm_get_connection_for_handle(con_handle); 3187 if (!sm_conn) break; 3188 3189 sm_conn->sm_handle = con_handle; 3190 sm_conn->sm_role = packet[6]; 3191 sm_conn->sm_peer_addr_type = packet[7]; 3192 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3193 3194 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3195 3196 // reset security properties 3197 sm_conn->sm_connection_encrypted = 0; 3198 sm_conn->sm_connection_authenticated = 0; 3199 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3200 sm_conn->sm_le_db_index = -1; 3201 3202 // prepare CSRK lookup (does not involve setup) 3203 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3204 3205 // just connected -> everything else happens in sm_run() 3206 if (IS_RESPONDER(sm_conn->sm_role)){ 3207 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3208 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3209 if (sm_slave_request_security) { 3210 // request security if requested by app 3211 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3212 } else { 3213 // otherwise, wait for pairing request 3214 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3215 } 3216 } 3217 break; 3218 } else { 3219 // master 3220 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3221 } 3222 break; 3223 3224 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3225 con_handle = little_endian_read_16(packet, 3); 3226 sm_conn = sm_get_connection_for_handle(con_handle); 3227 if (!sm_conn) break; 3228 3229 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3230 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3231 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3232 break; 3233 } 3234 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3235 // PH2 SEND LTK as we need to exchange keys in PH3 3236 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3237 break; 3238 } 3239 3240 // store rand and ediv 3241 reverse_64(&packet[5], sm_conn->sm_local_rand); 3242 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3243 3244 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3245 // potentially stored LTK is from the master 3246 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3247 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3248 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3249 break; 3250 } 3251 // additionally check if remote is in LE Device DB if requested 3252 switch(sm_conn->sm_irk_lookup_state){ 3253 case IRK_LOOKUP_FAILED: 3254 log_info("LTK Request: device not in device db"); 3255 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3256 break; 3257 case IRK_LOOKUP_SUCCEEDED: 3258 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3259 break; 3260 default: 3261 // wait for irk look doen 3262 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3263 break; 3264 } 3265 break; 3266 } 3267 3268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3269 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3270 #else 3271 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3272 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3273 #endif 3274 break; 3275 3276 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3277 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3278 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3279 log_error("Read Local P256 Public Key failed"); 3280 break; 3281 } 3282 3283 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3284 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3285 3286 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3287 sm_log_ec_keypair(); 3288 break; 3289 case HCI_SUBEVENT_LE_GENERATE_DHKEY_COMPLETE: 3290 sm_conn = sm_get_connection_for_handle(sm_active_connection_handle); 3291 if (hci_subevent_le_generate_dhkey_complete_get_status(packet)){ 3292 log_error("Generate DHKEY failed -> abort"); 3293 // abort pairing with 'unspecified reason' 3294 sm_pdu_received_in_wrong_state(sm_conn); 3295 break; 3296 } 3297 3298 hci_subevent_le_generate_dhkey_complete_get_dhkey(packet, &setup->sm_dhkey[0]); 3299 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 3300 log_info("dhkey"); 3301 log_info_hexdump(&setup->sm_dhkey[0], 32); 3302 3303 // trigger next step 3304 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 3305 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 3306 } 3307 break; 3308 #endif 3309 default: 3310 break; 3311 } 3312 break; 3313 3314 case HCI_EVENT_ENCRYPTION_CHANGE: 3315 con_handle = little_endian_read_16(packet, 3); 3316 sm_conn = sm_get_connection_for_handle(con_handle); 3317 if (!sm_conn) break; 3318 3319 sm_conn->sm_connection_encrypted = packet[5]; 3320 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3321 sm_conn->sm_actual_encryption_key_size); 3322 log_info("event handler, state %u", sm_conn->sm_engine_state); 3323 if (!sm_conn->sm_connection_encrypted) break; 3324 // continue if part of initial pairing 3325 switch (sm_conn->sm_engine_state){ 3326 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3327 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3328 sm_done_for_handle(sm_conn->sm_handle); 3329 break; 3330 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3331 if (IS_RESPONDER(sm_conn->sm_role)){ 3332 // slave 3333 if (setup->sm_use_secure_connections){ 3334 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3335 } else { 3336 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3337 } 3338 } else { 3339 // master 3340 if (sm_key_distribution_all_received(sm_conn)){ 3341 // skip receiving keys as there are none 3342 sm_key_distribution_handle_all_received(sm_conn); 3343 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3344 } else { 3345 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3346 } 3347 } 3348 break; 3349 default: 3350 break; 3351 } 3352 break; 3353 3354 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3355 con_handle = little_endian_read_16(packet, 3); 3356 sm_conn = sm_get_connection_for_handle(con_handle); 3357 if (!sm_conn) break; 3358 3359 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3360 log_info("event handler, state %u", sm_conn->sm_engine_state); 3361 // continue if part of initial pairing 3362 switch (sm_conn->sm_engine_state){ 3363 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3364 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3365 sm_done_for_handle(sm_conn->sm_handle); 3366 break; 3367 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3368 if (IS_RESPONDER(sm_conn->sm_role)){ 3369 // slave 3370 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3371 } else { 3372 // master 3373 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3374 } 3375 break; 3376 default: 3377 break; 3378 } 3379 break; 3380 3381 3382 case HCI_EVENT_DISCONNECTION_COMPLETE: 3383 con_handle = little_endian_read_16(packet, 3); 3384 sm_done_for_handle(con_handle); 3385 sm_conn = sm_get_connection_for_handle(con_handle); 3386 if (!sm_conn) break; 3387 3388 // delete stored bonding on disconnect with authentication failure in ph0 3389 if (sm_conn->sm_role == 0 3390 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3391 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3392 le_device_db_remove(sm_conn->sm_le_db_index); 3393 } 3394 3395 // pairing failed, if it was ongoing 3396 if (sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED && sm_conn->sm_engine_state != SM_GENERAL_IDLE){ 3397 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3398 } 3399 3400 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3401 sm_conn->sm_handle = 0; 3402 break; 3403 3404 case HCI_EVENT_COMMAND_COMPLETE: 3405 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3406 sm_handle_encryption_result(&packet[6]); 3407 break; 3408 } 3409 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3410 sm_handle_random_result(&packet[6]); 3411 break; 3412 } 3413 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3414 // set local addr for le device db 3415 bd_addr_t addr; 3416 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3417 le_device_db_set_local_bd_addr(addr); 3418 } 3419 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_local_supported_commands)){ 3420 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3421 if ((packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE+1+34] & 0x06) != 0x06){ 3422 // mbedTLS can also be used if already available (and malloc is supported) 3423 log_error("LE Secure Connections enabled, but HCI Controller doesn't support it. Please add USE_MICRO_ECC_FOR_ECDH to btstack_config.h"); 3424 } 3425 #endif 3426 } 3427 break; 3428 default: 3429 break; 3430 } 3431 break; 3432 default: 3433 break; 3434 } 3435 3436 sm_run(); 3437 } 3438 3439 static inline int sm_calc_actual_encryption_key_size(int other){ 3440 if (other < sm_min_encryption_key_size) return 0; 3441 if (other < sm_max_encryption_key_size) return other; 3442 return sm_max_encryption_key_size; 3443 } 3444 3445 3446 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3447 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3448 switch (method){ 3449 case JUST_WORKS: 3450 case NK_BOTH_INPUT: 3451 return 1; 3452 default: 3453 return 0; 3454 } 3455 } 3456 // responder 3457 3458 static int sm_passkey_used(stk_generation_method_t method){ 3459 switch (method){ 3460 case PK_RESP_INPUT: 3461 return 1; 3462 default: 3463 return 0; 3464 } 3465 } 3466 #endif 3467 3468 /** 3469 * @return ok 3470 */ 3471 static int sm_validate_stk_generation_method(void){ 3472 // check if STK generation method is acceptable by client 3473 switch (setup->sm_stk_generation_method){ 3474 case JUST_WORKS: 3475 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3476 case PK_RESP_INPUT: 3477 case PK_INIT_INPUT: 3478 case OK_BOTH_INPUT: 3479 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3480 case OOB: 3481 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3482 case NK_BOTH_INPUT: 3483 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3484 return 1; 3485 default: 3486 return 0; 3487 } 3488 } 3489 3490 // size of complete sm_pdu used to validate input 3491 static const uint8_t sm_pdu_size[] = { 3492 0, // 0x00 invalid opcode 3493 7, // 0x01 pairing request 3494 7, // 0x02 pairing response 3495 17, // 0x03 pairing confirm 3496 17, // 0x04 pairing random 3497 2, // 0x05 pairing failed 3498 17, // 0x06 encryption information 3499 11, // 0x07 master identification 3500 17, // 0x08 identification information 3501 8, // 0x09 identify address information 3502 17, // 0x0a signing information 3503 2, // 0x0b security request 3504 65, // 0x0c pairing public key 3505 17, // 0x0d pairing dhk check 3506 2, // 0x0e keypress notification 3507 }; 3508 3509 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3510 3511 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3512 sm_run(); 3513 } 3514 3515 if (packet_type != SM_DATA_PACKET) return; 3516 if (size == 0) return; 3517 3518 uint8_t sm_pdu_code = packet[0]; 3519 3520 // validate pdu size 3521 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3522 if (sm_pdu_size[sm_pdu_code] != size) return; 3523 3524 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3525 if (!sm_conn) return; 3526 3527 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3528 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3529 sm_done_for_handle(con_handle); 3530 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3531 return; 3532 } 3533 3534 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3535 3536 int err; 3537 UNUSED(err); 3538 3539 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3540 uint8_t buffer[5]; 3541 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3542 buffer[1] = 3; 3543 little_endian_store_16(buffer, 2, con_handle); 3544 buffer[4] = packet[1]; 3545 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3546 return; 3547 } 3548 3549 switch (sm_conn->sm_engine_state){ 3550 3551 // a sm timeout requries a new physical connection 3552 case SM_GENERAL_TIMEOUT: 3553 return; 3554 3555 #ifdef ENABLE_LE_CENTRAL 3556 3557 // Initiator 3558 case SM_INITIATOR_CONNECTED: 3559 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3560 sm_pdu_received_in_wrong_state(sm_conn); 3561 break; 3562 } 3563 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3564 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3565 break; 3566 } 3567 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3568 sm_key_t ltk; 3569 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3570 if (!sm_is_null_key(ltk)){ 3571 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3572 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3573 } else { 3574 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3575 } 3576 break; 3577 } 3578 // otherwise, store security request 3579 sm_conn->sm_security_request_received = 1; 3580 break; 3581 3582 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3583 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3584 sm_pdu_received_in_wrong_state(sm_conn); 3585 break; 3586 } 3587 3588 // store pairing request 3589 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3590 err = sm_stk_generation_init(sm_conn); 3591 3592 #ifdef ENABLE_TESTING_SUPPORT 3593 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3594 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3595 err = test_pairing_failure; 3596 } 3597 #endif 3598 3599 if (err){ 3600 setup->sm_pairing_failed_reason = err; 3601 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3602 break; 3603 } 3604 3605 // generate random number first, if we need to show passkey 3606 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3607 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3608 break; 3609 } 3610 3611 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3612 if (setup->sm_use_secure_connections){ 3613 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3614 if (setup->sm_stk_generation_method == JUST_WORKS){ 3615 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3616 sm_trigger_user_response(sm_conn); 3617 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3618 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3619 } 3620 } else { 3621 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3622 } 3623 break; 3624 } 3625 #endif 3626 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3627 sm_trigger_user_response(sm_conn); 3628 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3629 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3630 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3631 } 3632 break; 3633 3634 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3635 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3636 sm_pdu_received_in_wrong_state(sm_conn); 3637 break; 3638 } 3639 3640 // store s_confirm 3641 reverse_128(&packet[1], setup->sm_peer_confirm); 3642 3643 #ifdef ENABLE_TESTING_SUPPORT 3644 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3645 log_info("testing_support: reset confirm value"); 3646 memset(setup->sm_peer_confirm, 0, 16); 3647 } 3648 #endif 3649 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3650 break; 3651 3652 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3653 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3654 sm_pdu_received_in_wrong_state(sm_conn); 3655 break;; 3656 } 3657 3658 // received random value 3659 reverse_128(&packet[1], setup->sm_peer_random); 3660 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3661 break; 3662 #endif 3663 3664 #ifdef ENABLE_LE_PERIPHERAL 3665 // Responder 3666 case SM_RESPONDER_IDLE: 3667 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3668 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3669 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3670 sm_pdu_received_in_wrong_state(sm_conn); 3671 break;; 3672 } 3673 3674 // store pairing request 3675 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3676 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3677 break; 3678 #endif 3679 3680 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3681 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3682 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3683 sm_pdu_received_in_wrong_state(sm_conn); 3684 break; 3685 } 3686 3687 // store public key for DH Key calculation 3688 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3689 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3690 3691 // validate public key using micro-ecc 3692 err = 0; 3693 3694 #ifdef USE_MICRO_ECC_FOR_ECDH 3695 #if uECC_SUPPORTS_secp256r1 3696 // standard version 3697 err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0; 3698 #else 3699 // static version 3700 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3701 #endif 3702 #endif 3703 3704 #ifdef USE_MBEDTLS_FOR_ECDH 3705 mbedtls_ecp_point Q; 3706 mbedtls_ecp_point_init( &Q ); 3707 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); 3708 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 3709 mbedtls_mpi_lset(&Q.Z, 1); 3710 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3711 mbedtls_ecp_point_free( & Q); 3712 #endif 3713 3714 if (err){ 3715 log_error("sm: peer public key invalid %x", err); 3716 // uses "unspecified reason", there is no "public key invalid" error code 3717 sm_pdu_received_in_wrong_state(sm_conn); 3718 break; 3719 } 3720 3721 #ifndef USE_SOFTWARE_ECDH_IMPLEMENTATION 3722 // ask controller to calculate dhkey 3723 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_NEEDED; 3724 #endif 3725 3726 3727 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3728 if (IS_RESPONDER(sm_conn->sm_role)){ 3729 // responder 3730 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3731 } else { 3732 // initiator 3733 // stk generation method 3734 // passkey entry: notify app to show passkey or to request passkey 3735 switch (setup->sm_stk_generation_method){ 3736 case JUST_WORKS: 3737 case NK_BOTH_INPUT: 3738 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3739 break; 3740 case PK_RESP_INPUT: 3741 sm_sc_start_calculating_local_confirm(sm_conn); 3742 break; 3743 case PK_INIT_INPUT: 3744 case OK_BOTH_INPUT: 3745 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3746 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3747 break; 3748 } 3749 sm_sc_start_calculating_local_confirm(sm_conn); 3750 break; 3751 case OOB: 3752 // generate Nx 3753 log_info("Generate Nx"); 3754 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3755 break; 3756 } 3757 } 3758 break; 3759 3760 case SM_SC_W4_CONFIRMATION: 3761 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3762 sm_pdu_received_in_wrong_state(sm_conn); 3763 break; 3764 } 3765 // received confirm value 3766 reverse_128(&packet[1], setup->sm_peer_confirm); 3767 3768 #ifdef ENABLE_TESTING_SUPPORT 3769 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3770 log_info("testing_support: reset confirm value"); 3771 memset(setup->sm_peer_confirm, 0, 16); 3772 } 3773 #endif 3774 if (IS_RESPONDER(sm_conn->sm_role)){ 3775 // responder 3776 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3777 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3778 // still waiting for passkey 3779 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3780 break; 3781 } 3782 } 3783 sm_sc_start_calculating_local_confirm(sm_conn); 3784 } else { 3785 // initiator 3786 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3787 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3788 } else { 3789 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3790 } 3791 } 3792 break; 3793 3794 case SM_SC_W4_PAIRING_RANDOM: 3795 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3796 sm_pdu_received_in_wrong_state(sm_conn); 3797 break; 3798 } 3799 3800 // received random value 3801 reverse_128(&packet[1], setup->sm_peer_nonce); 3802 3803 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3804 // only check for JUST WORK/NC in initiator role OR passkey entry 3805 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3806 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3807 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3808 break; 3809 } 3810 3811 sm_sc_state_after_receiving_random(sm_conn); 3812 break; 3813 3814 case SM_SC_W2_CALCULATE_G2: 3815 case SM_SC_W4_CALCULATE_G2: 3816 case SM_SC_W4_CALCULATE_DHKEY: 3817 case SM_SC_W2_CALCULATE_F5_SALT: 3818 case SM_SC_W4_CALCULATE_F5_SALT: 3819 case SM_SC_W2_CALCULATE_F5_MACKEY: 3820 case SM_SC_W4_CALCULATE_F5_MACKEY: 3821 case SM_SC_W2_CALCULATE_F5_LTK: 3822 case SM_SC_W4_CALCULATE_F5_LTK: 3823 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3824 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3825 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3826 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3827 sm_pdu_received_in_wrong_state(sm_conn); 3828 break; 3829 } 3830 // store DHKey Check 3831 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3832 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3833 3834 // have we been only waiting for dhkey check command? 3835 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3836 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3837 } 3838 break; 3839 #endif 3840 3841 #ifdef ENABLE_LE_PERIPHERAL 3842 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3843 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3844 sm_pdu_received_in_wrong_state(sm_conn); 3845 break; 3846 } 3847 3848 // received confirm value 3849 reverse_128(&packet[1], setup->sm_peer_confirm); 3850 3851 #ifdef ENABLE_TESTING_SUPPORT 3852 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3853 log_info("testing_support: reset confirm value"); 3854 memset(setup->sm_peer_confirm, 0, 16); 3855 } 3856 #endif 3857 // notify client to hide shown passkey 3858 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3859 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3860 } 3861 3862 // handle user cancel pairing? 3863 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3864 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3865 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3866 break; 3867 } 3868 3869 // wait for user action? 3870 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3871 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3872 break; 3873 } 3874 3875 // calculate and send local_confirm 3876 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3877 break; 3878 3879 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3880 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3881 sm_pdu_received_in_wrong_state(sm_conn); 3882 break;; 3883 } 3884 3885 // received random value 3886 reverse_128(&packet[1], setup->sm_peer_random); 3887 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3888 break; 3889 #endif 3890 3891 case SM_PH3_RECEIVE_KEYS: 3892 switch(sm_pdu_code){ 3893 case SM_CODE_ENCRYPTION_INFORMATION: 3894 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3895 reverse_128(&packet[1], setup->sm_peer_ltk); 3896 break; 3897 3898 case SM_CODE_MASTER_IDENTIFICATION: 3899 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3900 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3901 reverse_64(&packet[3], setup->sm_peer_rand); 3902 break; 3903 3904 case SM_CODE_IDENTITY_INFORMATION: 3905 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3906 reverse_128(&packet[1], setup->sm_peer_irk); 3907 break; 3908 3909 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3910 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3911 setup->sm_peer_addr_type = packet[1]; 3912 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3913 break; 3914 3915 case SM_CODE_SIGNING_INFORMATION: 3916 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3917 reverse_128(&packet[1], setup->sm_peer_csrk); 3918 break; 3919 default: 3920 // Unexpected PDU 3921 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3922 break; 3923 } 3924 // done with key distribution? 3925 if (sm_key_distribution_all_received(sm_conn)){ 3926 3927 sm_key_distribution_handle_all_received(sm_conn); 3928 3929 if (IS_RESPONDER(sm_conn->sm_role)){ 3930 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3931 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3932 } else { 3933 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3934 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3935 sm_done_for_handle(sm_conn->sm_handle); 3936 } 3937 } else { 3938 if (setup->sm_use_secure_connections){ 3939 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3940 } else { 3941 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3942 } 3943 } 3944 } 3945 break; 3946 default: 3947 // Unexpected PDU 3948 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3949 break; 3950 } 3951 3952 // try to send preparared packet 3953 sm_run(); 3954 } 3955 3956 // Security Manager Client API 3957 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3958 sm_get_oob_data = get_oob_data_callback; 3959 } 3960 3961 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3962 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3963 } 3964 3965 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3966 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3967 } 3968 3969 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3970 sm_min_encryption_key_size = min_size; 3971 sm_max_encryption_key_size = max_size; 3972 } 3973 3974 void sm_set_authentication_requirements(uint8_t auth_req){ 3975 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3976 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3977 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3978 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3979 } 3980 #endif 3981 sm_auth_req = auth_req; 3982 } 3983 3984 void sm_set_io_capabilities(io_capability_t io_capability){ 3985 sm_io_capabilities = io_capability; 3986 } 3987 3988 #ifdef ENABLE_LE_PERIPHERAL 3989 void sm_set_request_security(int enable){ 3990 sm_slave_request_security = enable; 3991 } 3992 #endif 3993 3994 void sm_set_er(sm_key_t er){ 3995 memcpy(sm_persistent_er, er, 16); 3996 } 3997 3998 void sm_set_ir(sm_key_t ir){ 3999 memcpy(sm_persistent_ir, ir, 16); 4000 } 4001 4002 // Testing support only 4003 void sm_test_set_irk(sm_key_t irk){ 4004 memcpy(sm_persistent_irk, irk, 16); 4005 sm_persistent_irk_ready = 1; 4006 } 4007 4008 void sm_test_use_fixed_local_csrk(void){ 4009 test_use_fixed_local_csrk = 1; 4010 } 4011 4012 #ifdef ENABLE_TESTING_SUPPORT 4013 void sm_test_set_pairing_failure(int reason){ 4014 test_pairing_failure = reason; 4015 } 4016 #endif 4017 4018 void sm_init(void){ 4019 // set some (BTstack default) ER and IR 4020 int i; 4021 sm_key_t er; 4022 sm_key_t ir; 4023 for (i=0;i<16;i++){ 4024 er[i] = 0x30 + i; 4025 ir[i] = 0x90 + i; 4026 } 4027 sm_set_er(er); 4028 sm_set_ir(ir); 4029 // defaults 4030 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4031 | SM_STK_GENERATION_METHOD_OOB 4032 | SM_STK_GENERATION_METHOD_PASSKEY 4033 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4034 4035 sm_max_encryption_key_size = 16; 4036 sm_min_encryption_key_size = 7; 4037 4038 sm_fixed_passkey_in_display_role = 0xffffffff; 4039 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4040 4041 #ifdef ENABLE_CMAC_ENGINE 4042 sm_cmac_state = CMAC_IDLE; 4043 #endif 4044 dkg_state = DKG_W4_WORKING; 4045 rau_state = RAU_W4_WORKING; 4046 sm_aes128_state = SM_AES128_IDLE; 4047 sm_address_resolution_test = -1; // no private address to resolve yet 4048 sm_address_resolution_ah_calculation_active = 0; 4049 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4050 sm_address_resolution_general_queue = NULL; 4051 4052 gap_random_adress_update_period = 15 * 60 * 1000L; 4053 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4054 4055 test_use_fixed_local_csrk = 0; 4056 4057 // register for HCI Events from HCI 4058 hci_event_callback_registration.callback = &sm_event_packet_handler; 4059 hci_add_event_handler(&hci_event_callback_registration); 4060 4061 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4062 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4063 4064 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4065 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4066 #endif 4067 4068 #ifdef USE_MBEDTLS_FOR_ECDH 4069 mbedtls_ecp_group_init(&mbedtls_ec_group); 4070 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 4071 #endif 4072 } 4073 4074 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 4075 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4076 memcpy(&ec_q[0], qx, 32); 4077 memcpy(&ec_q[32], qy, 32); 4078 memcpy(ec_d, d, 32); 4079 sm_have_ec_keypair = 1; 4080 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4081 #else 4082 UNUSED(qx); 4083 UNUSED(qy); 4084 UNUSED(d); 4085 #endif 4086 } 4087 4088 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4089 static void parse_hex(uint8_t * buffer, const char * hex_string){ 4090 while (*hex_string){ 4091 int high_nibble = nibble_for_char(*hex_string++); 4092 int low_nibble = nibble_for_char(*hex_string++); 4093 *buffer++ = (high_nibble << 4) | low_nibble; 4094 } 4095 } 4096 #endif 4097 4098 void sm_test_use_fixed_ec_keypair(void){ 4099 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4100 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 4101 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 4102 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 4103 parse_hex(ec_d, ec_d_string); 4104 parse_hex(&ec_q[0], ec_qx_string); 4105 parse_hex(&ec_q[32], ec_qy_string); 4106 sm_have_ec_keypair = 1; 4107 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4108 #endif 4109 } 4110 4111 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4112 sm_fixed_passkey_in_display_role = passkey; 4113 } 4114 4115 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4116 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4117 } 4118 4119 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4120 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4121 if (!hci_con) return NULL; 4122 return &hci_con->sm_connection; 4123 } 4124 4125 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4126 switch (sm_conn->sm_engine_state){ 4127 case SM_GENERAL_IDLE: 4128 case SM_RESPONDER_IDLE: 4129 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4130 sm_run(); 4131 break; 4132 default: 4133 break; 4134 } 4135 } 4136 4137 /** 4138 * @brief Trigger Security Request 4139 */ 4140 void sm_send_security_request(hci_con_handle_t con_handle){ 4141 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4142 if (!sm_conn) return; 4143 sm_send_security_request_for_connection(sm_conn); 4144 } 4145 4146 // request pairing 4147 void sm_request_pairing(hci_con_handle_t con_handle){ 4148 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4149 if (!sm_conn) return; // wrong connection 4150 4151 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4152 if (IS_RESPONDER(sm_conn->sm_role)){ 4153 sm_send_security_request_for_connection(sm_conn); 4154 } else { 4155 // used as a trigger to start central/master/initiator security procedures 4156 uint16_t ediv; 4157 sm_key_t ltk; 4158 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4159 switch (sm_conn->sm_irk_lookup_state){ 4160 case IRK_LOOKUP_FAILED: 4161 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4162 break; 4163 case IRK_LOOKUP_SUCCEEDED: 4164 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 4165 if (!sm_is_null_key(ltk) || ediv){ 4166 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 4167 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4168 } else { 4169 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4170 } 4171 break; 4172 default: 4173 sm_conn->sm_pairing_requested = 1; 4174 break; 4175 } 4176 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4177 sm_conn->sm_pairing_requested = 1; 4178 } 4179 } 4180 sm_run(); 4181 } 4182 4183 // called by client app on authorization request 4184 void sm_authorization_decline(hci_con_handle_t con_handle){ 4185 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4186 if (!sm_conn) return; // wrong connection 4187 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4188 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4189 } 4190 4191 void sm_authorization_grant(hci_con_handle_t con_handle){ 4192 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4193 if (!sm_conn) return; // wrong connection 4194 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4195 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4196 } 4197 4198 // GAP Bonding API 4199 4200 void sm_bonding_decline(hci_con_handle_t con_handle){ 4201 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4202 if (!sm_conn) return; // wrong connection 4203 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4204 log_info("decline, state %u", sm_conn->sm_engine_state); 4205 switch(sm_conn->sm_engine_state){ 4206 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4207 case SM_SC_W4_USER_RESPONSE: 4208 case SM_SC_W4_CONFIRMATION: 4209 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4210 #endif 4211 case SM_PH1_W4_USER_RESPONSE: 4212 switch (setup->sm_stk_generation_method){ 4213 case PK_RESP_INPUT: 4214 case PK_INIT_INPUT: 4215 case OK_BOTH_INPUT: 4216 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4217 break; 4218 case NK_BOTH_INPUT: 4219 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4220 break; 4221 case JUST_WORKS: 4222 case OOB: 4223 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4224 break; 4225 } 4226 break; 4227 default: 4228 break; 4229 } 4230 sm_run(); 4231 } 4232 4233 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4234 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4235 if (!sm_conn) return; // wrong connection 4236 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4237 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4238 if (setup->sm_use_secure_connections){ 4239 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4240 } else { 4241 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4242 } 4243 } 4244 4245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4246 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4247 sm_sc_prepare_dhkey_check(sm_conn); 4248 } 4249 #endif 4250 4251 sm_run(); 4252 } 4253 4254 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4255 // for now, it's the same 4256 sm_just_works_confirm(con_handle); 4257 } 4258 4259 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4260 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4261 if (!sm_conn) return; // wrong connection 4262 sm_reset_tk(); 4263 big_endian_store_32(setup->sm_tk, 12, passkey); 4264 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4265 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4266 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4267 } 4268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4269 memcpy(setup->sm_ra, setup->sm_tk, 16); 4270 memcpy(setup->sm_rb, setup->sm_tk, 16); 4271 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4272 sm_sc_start_calculating_local_confirm(sm_conn); 4273 } 4274 #endif 4275 sm_run(); 4276 } 4277 4278 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4279 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4280 if (!sm_conn) return; // wrong connection 4281 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4282 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4283 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4284 switch (action){ 4285 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4286 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4287 flags |= (1 << action); 4288 break; 4289 case SM_KEYPRESS_PASSKEY_CLEARED: 4290 // clear counter, keypress & erased flags + set passkey cleared 4291 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4292 break; 4293 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4294 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4295 // erase actions queued 4296 num_actions--; 4297 if (num_actions == 0){ 4298 // clear counter, keypress & erased flags 4299 flags &= 0x19; 4300 } 4301 break; 4302 } 4303 num_actions++; 4304 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4305 break; 4306 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4307 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4308 // enter actions queued 4309 num_actions--; 4310 if (num_actions == 0){ 4311 // clear counter, keypress & erased flags 4312 flags &= 0x19; 4313 } 4314 break; 4315 } 4316 num_actions++; 4317 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4318 break; 4319 default: 4320 break; 4321 } 4322 setup->sm_keypress_notification = (num_actions << 5) | flags; 4323 sm_run(); 4324 } 4325 4326 /** 4327 * @brief Identify device in LE Device DB 4328 * @param handle 4329 * @returns index from le_device_db or -1 if not found/identified 4330 */ 4331 int sm_le_device_index(hci_con_handle_t con_handle ){ 4332 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4333 if (!sm_conn) return -1; 4334 return sm_conn->sm_le_db_index; 4335 } 4336 4337 static int gap_random_address_type_requires_updates(void){ 4338 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4339 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4340 return 1; 4341 } 4342 4343 static uint8_t own_address_type(void){ 4344 switch (gap_random_adress_type){ 4345 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4346 return BD_ADDR_TYPE_LE_PUBLIC; 4347 default: 4348 return BD_ADDR_TYPE_LE_RANDOM; 4349 } 4350 } 4351 4352 // GAP LE API 4353 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4354 gap_random_address_update_stop(); 4355 gap_random_adress_type = random_address_type; 4356 hci_le_set_own_address_type(own_address_type()); 4357 if (!gap_random_address_type_requires_updates()) return; 4358 gap_random_address_update_start(); 4359 gap_random_address_trigger(); 4360 } 4361 4362 gap_random_address_type_t gap_random_address_get_mode(void){ 4363 return gap_random_adress_type; 4364 } 4365 4366 void gap_random_address_set_update_period(int period_ms){ 4367 gap_random_adress_update_period = period_ms; 4368 if (!gap_random_address_type_requires_updates()) return; 4369 gap_random_address_update_stop(); 4370 gap_random_address_update_start(); 4371 } 4372 4373 void gap_random_address_set(bd_addr_t addr){ 4374 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4375 memcpy(sm_random_address, addr, 6); 4376 if (rau_state == RAU_W4_WORKING) return; 4377 rau_state = RAU_SET_ADDRESS; 4378 sm_run(); 4379 } 4380 4381 #ifdef ENABLE_LE_PERIPHERAL 4382 /* 4383 * @brief Set Advertisement Paramters 4384 * @param adv_int_min 4385 * @param adv_int_max 4386 * @param adv_type 4387 * @param direct_address_type 4388 * @param direct_address 4389 * @param channel_map 4390 * @param filter_policy 4391 * 4392 * @note own_address_type is used from gap_random_address_set_mode 4393 */ 4394 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4395 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4396 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4397 direct_address_typ, direct_address, channel_map, filter_policy); 4398 } 4399 #endif 4400