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 // 191 // GLOBAL DATA 192 // 193 194 static uint8_t test_use_fixed_local_csrk; 195 196 // configuration 197 static uint8_t sm_accepted_stk_generation_methods; 198 static uint8_t sm_max_encryption_key_size; 199 static uint8_t sm_min_encryption_key_size; 200 static uint8_t sm_auth_req = 0; 201 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 202 static uint8_t sm_slave_request_security; 203 static uint32_t sm_fixed_passkey_in_display_role; 204 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 205 #ifdef ENABLE_LE_SECURE_CONNECTIONS 206 static uint8_t sm_have_ec_keypair; 207 #endif 208 209 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 210 static sm_key_t sm_persistent_er; 211 static sm_key_t sm_persistent_ir; 212 213 // derived from sm_persistent_ir 214 static sm_key_t sm_persistent_dhk; 215 static sm_key_t sm_persistent_irk; 216 static uint8_t sm_persistent_irk_ready = 0; // used for testing 217 static derived_key_generation_t dkg_state; 218 219 // derived from sm_persistent_er 220 // .. 221 222 // random address update 223 static random_address_update_t rau_state; 224 static bd_addr_t sm_random_address; 225 226 // CMAC Calculation: General 227 #ifdef ENABLE_CMAC_ENGINE 228 static cmac_state_t sm_cmac_state; 229 static uint16_t sm_cmac_message_len; 230 static sm_key_t sm_cmac_k; 231 static sm_key_t sm_cmac_x; 232 static sm_key_t sm_cmac_m_last; 233 static uint8_t sm_cmac_block_current; 234 static uint8_t sm_cmac_block_count; 235 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 236 static void (*sm_cmac_done_handler)(uint8_t * hash); 237 #endif 238 239 // CMAC for ATT Signed Writes 240 #ifdef ENABLE_LE_SIGNED_WRITE 241 static uint8_t sm_cmac_header[3]; 242 static const uint8_t * sm_cmac_message; 243 static uint8_t sm_cmac_sign_counter[4]; 244 #endif 245 246 // CMAC for Secure Connection functions 247 #ifdef ENABLE_LE_SECURE_CONNECTIONS 248 static sm_connection_t * sm_cmac_connection; 249 static uint8_t sm_cmac_sc_buffer[80]; 250 #endif 251 252 // resolvable private address lookup / CSRK calculation 253 static int sm_address_resolution_test; 254 static int sm_address_resolution_ah_calculation_active; 255 static uint8_t sm_address_resolution_addr_type; 256 static bd_addr_t sm_address_resolution_address; 257 static void * sm_address_resolution_context; 258 static address_resolution_mode_t sm_address_resolution_mode; 259 static btstack_linked_list_t sm_address_resolution_general_queue; 260 261 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 262 static sm_aes128_state_t sm_aes128_state; 263 static void * sm_aes128_context; 264 265 // use aes128 provided by MCU - not needed usually 266 #ifdef HAVE_AES128 267 static uint8_t aes128_result_flipped[16]; 268 static btstack_timer_source_t aes128_timer; 269 void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result); 270 #endif 271 272 // random engine. store context (ususally sm_connection_t) 273 static void * sm_random_context; 274 275 // to receive hci events 276 static btstack_packet_callback_registration_t hci_event_callback_registration; 277 278 /* to dispatch sm event */ 279 static btstack_linked_list_t sm_event_handlers; 280 281 // LE Secure Connections 282 #ifdef ENABLE_LE_SECURE_CONNECTIONS 283 static ec_key_generation_state_t ec_key_generation_state; 284 static uint8_t ec_d[32]; 285 static uint8_t ec_q[64]; 286 #endif 287 288 // Software ECDH implementation provided by mbedtls 289 #ifdef USE_MBEDTLS_FOR_ECDH 290 static mbedtls_ecp_group mbedtls_ec_group; 291 #endif 292 293 // 294 // Volume 3, Part H, Chapter 24 295 // "Security shall be initiated by the Security Manager in the device in the master role. 296 // The device in the slave role shall be the responding device." 297 // -> master := initiator, slave := responder 298 // 299 300 // data needed for security setup 301 typedef struct sm_setup_context { 302 303 btstack_timer_source_t sm_timeout; 304 305 // used in all phases 306 uint8_t sm_pairing_failed_reason; 307 308 // user response, (Phase 1 and/or 2) 309 uint8_t sm_user_response; 310 uint8_t sm_keypress_notification; 311 312 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 313 int sm_key_distribution_send_set; 314 int sm_key_distribution_received_set; 315 316 // Phase 2 (Pairing over SMP) 317 stk_generation_method_t sm_stk_generation_method; 318 sm_key_t sm_tk; 319 uint8_t sm_use_secure_connections; 320 321 sm_key_t sm_c1_t3_value; // c1 calculation 322 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 323 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 324 sm_key_t sm_local_random; 325 sm_key_t sm_local_confirm; 326 sm_key_t sm_peer_random; 327 sm_key_t sm_peer_confirm; 328 uint8_t sm_m_addr_type; // address and type can be removed 329 uint8_t sm_s_addr_type; // '' 330 bd_addr_t sm_m_address; // '' 331 bd_addr_t sm_s_address; // '' 332 sm_key_t sm_ltk; 333 334 uint8_t sm_state_vars; 335 #ifdef ENABLE_LE_SECURE_CONNECTIONS 336 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 337 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 338 sm_key_t sm_local_nonce; // might be combined with sm_local_random 339 sm_key_t sm_dhkey; 340 sm_key_t sm_peer_dhkey_check; 341 sm_key_t sm_local_dhkey_check; 342 sm_key_t sm_ra; 343 sm_key_t sm_rb; 344 sm_key_t sm_t; // used for f5 and h6 345 sm_key_t sm_mackey; 346 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 347 #endif 348 349 // Phase 3 350 351 // key distribution, we generate 352 uint16_t sm_local_y; 353 uint16_t sm_local_div; 354 uint16_t sm_local_ediv; 355 uint8_t sm_local_rand[8]; 356 sm_key_t sm_local_ltk; 357 sm_key_t sm_local_csrk; 358 sm_key_t sm_local_irk; 359 // sm_local_address/addr_type not needed 360 361 // key distribution, received from peer 362 uint16_t sm_peer_y; 363 uint16_t sm_peer_div; 364 uint16_t sm_peer_ediv; 365 uint8_t sm_peer_rand[8]; 366 sm_key_t sm_peer_ltk; 367 sm_key_t sm_peer_irk; 368 sm_key_t sm_peer_csrk; 369 uint8_t sm_peer_addr_type; 370 bd_addr_t sm_peer_address; 371 372 } sm_setup_context_t; 373 374 // 375 static sm_setup_context_t the_setup; 376 static sm_setup_context_t * setup = &the_setup; 377 378 // active connection - the one for which the_setup is used for 379 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 380 381 // @returns 1 if oob data is available 382 // stores oob data in provided 16 byte buffer if not null 383 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 384 385 // horizontal: initiator capabilities 386 // vertial: responder capabilities 387 static const stk_generation_method_t stk_generation_method [5] [5] = { 388 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 389 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 390 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 391 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 392 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 393 }; 394 395 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 396 #ifdef ENABLE_LE_SECURE_CONNECTIONS 397 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 398 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 399 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 400 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 401 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 402 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 403 }; 404 #endif 405 406 static void sm_run(void); 407 static void sm_done_for_handle(hci_con_handle_t con_handle); 408 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 409 static inline int sm_calc_actual_encryption_key_size(int other); 410 static int sm_validate_stk_generation_method(void); 411 static void sm_handle_encryption_result(uint8_t * data); 412 413 static void log_info_hex16(const char * name, uint16_t value){ 414 log_info("%-6s 0x%04x", name, value); 415 } 416 417 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 418 // return packet[0]; 419 // } 420 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 421 return packet[1]; 422 } 423 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 424 return packet[2]; 425 } 426 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 427 return packet[3]; 428 } 429 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 430 return packet[4]; 431 } 432 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 433 return packet[5]; 434 } 435 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 436 return packet[6]; 437 } 438 439 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 440 packet[0] = code; 441 } 442 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 443 packet[1] = io_capability; 444 } 445 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 446 packet[2] = oob_data_flag; 447 } 448 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 449 packet[3] = auth_req; 450 } 451 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 452 packet[4] = max_encryption_key_size; 453 } 454 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 455 packet[5] = initiator_key_distribution; 456 } 457 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 458 packet[6] = responder_key_distribution; 459 } 460 461 // @returns 1 if all bytes are 0 462 static int sm_is_null(uint8_t * data, int size){ 463 int i; 464 for (i=0; i < size ; i++){ 465 if (data[i]) return 0; 466 } 467 return 1; 468 } 469 470 static int sm_is_null_random(uint8_t random[8]){ 471 return sm_is_null(random, 8); 472 } 473 474 static int sm_is_null_key(uint8_t * key){ 475 return sm_is_null(key, 16); 476 } 477 478 // Key utils 479 static void sm_reset_tk(void){ 480 int i; 481 for (i=0;i<16;i++){ 482 setup->sm_tk[i] = 0; 483 } 484 } 485 486 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 487 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 488 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 489 int i; 490 for (i = max_encryption_size ; i < 16 ; i++){ 491 key[15-i] = 0; 492 } 493 } 494 495 // SMP Timeout implementation 496 497 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 498 // the Security Manager Timer shall be reset and started. 499 // 500 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 501 // 502 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 503 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 504 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 505 // established. 506 507 static void sm_timeout_handler(btstack_timer_source_t * timer){ 508 log_info("SM timeout"); 509 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 510 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 511 sm_done_for_handle(sm_conn->sm_handle); 512 513 // trigger handling of next ready connection 514 sm_run(); 515 } 516 static void sm_timeout_start(sm_connection_t * sm_conn){ 517 btstack_run_loop_remove_timer(&setup->sm_timeout); 518 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 519 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 520 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 521 btstack_run_loop_add_timer(&setup->sm_timeout); 522 } 523 static void sm_timeout_stop(void){ 524 btstack_run_loop_remove_timer(&setup->sm_timeout); 525 } 526 static void sm_timeout_reset(sm_connection_t * sm_conn){ 527 sm_timeout_stop(); 528 sm_timeout_start(sm_conn); 529 } 530 531 // end of sm timeout 532 533 // GAP Random Address updates 534 static gap_random_address_type_t gap_random_adress_type; 535 static btstack_timer_source_t gap_random_address_update_timer; 536 static uint32_t gap_random_adress_update_period; 537 538 static void gap_random_address_trigger(void){ 539 if (rau_state != RAU_IDLE) return; 540 log_info("gap_random_address_trigger"); 541 rau_state = RAU_GET_RANDOM; 542 sm_run(); 543 } 544 545 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 546 UNUSED(timer); 547 548 log_info("GAP Random Address Update due"); 549 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 550 btstack_run_loop_add_timer(&gap_random_address_update_timer); 551 gap_random_address_trigger(); 552 } 553 554 static void gap_random_address_update_start(void){ 555 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 556 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 557 btstack_run_loop_add_timer(&gap_random_address_update_timer); 558 } 559 560 static void gap_random_address_update_stop(void){ 561 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 562 } 563 564 565 static void sm_random_start(void * context){ 566 sm_random_context = context; 567 hci_send_cmd(&hci_le_rand); 568 } 569 570 #ifdef HAVE_AES128 571 static void aes128_completed(btstack_timer_source_t * ts){ 572 UNUSED(ts); 573 sm_handle_encryption_result(&aes128_result_flipped[0]); 574 sm_run(); 575 } 576 #endif 577 578 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 579 // context is made availabe to aes128 result handler by this 580 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 581 sm_aes128_state = SM_AES128_ACTIVE; 582 sm_aes128_context = context; 583 584 #ifdef HAVE_AES128 585 // calc result directly 586 sm_key_t result; 587 btstack_aes128_calc(key, plaintext, result); 588 589 // log 590 log_info_key("key", key); 591 log_info_key("txt", plaintext); 592 log_info_key("res", result); 593 594 // flip 595 reverse_128(&result[0], &aes128_result_flipped[0]); 596 597 // deliver via timer 598 btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed); 599 btstack_run_loop_set_timer(&aes128_timer, 0); // no delay 600 btstack_run_loop_add_timer(&aes128_timer); 601 #else 602 sm_key_t key_flipped, plaintext_flipped; 603 reverse_128(key, key_flipped); 604 reverse_128(plaintext, plaintext_flipped); 605 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 606 #endif 607 } 608 609 // ah(k,r) helper 610 // r = padding || r 611 // r - 24 bit value 612 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 613 // r'= padding || r 614 memset(r_prime, 0, 16); 615 memcpy(&r_prime[13], r, 3); 616 } 617 618 // d1 helper 619 // d' = padding || r || d 620 // d,r - 16 bit values 621 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 622 // d'= padding || r || d 623 memset(d1_prime, 0, 16); 624 big_endian_store_16(d1_prime, 12, r); 625 big_endian_store_16(d1_prime, 14, d); 626 } 627 628 // dm helper 629 // r’ = padding || r 630 // r - 64 bit value 631 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 632 memset(r_prime, 0, 16); 633 memcpy(&r_prime[8], r, 8); 634 } 635 636 // calculate arguments for first AES128 operation in C1 function 637 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){ 638 639 // p1 = pres || preq || rat’ || iat’ 640 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 641 // cant octet of pres becomes the most significant octet of p1. 642 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 643 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 644 // p1 is 0x05000800000302070710000001010001." 645 646 sm_key_t p1; 647 reverse_56(pres, &p1[0]); 648 reverse_56(preq, &p1[7]); 649 p1[14] = rat; 650 p1[15] = iat; 651 log_info_key("p1", p1); 652 log_info_key("r", r); 653 654 // t1 = r xor p1 655 int i; 656 for (i=0;i<16;i++){ 657 t1[i] = r[i] ^ p1[i]; 658 } 659 log_info_key("t1", t1); 660 } 661 662 // calculate arguments for second AES128 operation in C1 function 663 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 664 // p2 = padding || ia || ra 665 // "The least significant octet of ra becomes the least significant octet of p2 and 666 // the most significant octet of padding becomes the most significant octet of p2. 667 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 668 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 669 670 sm_key_t p2; 671 memset(p2, 0, 16); 672 memcpy(&p2[4], ia, 6); 673 memcpy(&p2[10], ra, 6); 674 log_info_key("p2", p2); 675 676 // c1 = e(k, t2_xor_p2) 677 int i; 678 for (i=0;i<16;i++){ 679 t3[i] = t2[i] ^ p2[i]; 680 } 681 log_info_key("t3", t3); 682 } 683 684 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 685 log_info_key("r1", r1); 686 log_info_key("r2", r2); 687 memcpy(&r_prime[8], &r2[8], 8); 688 memcpy(&r_prime[0], &r1[8], 8); 689 } 690 691 #ifdef ENABLE_LE_SECURE_CONNECTIONS 692 // Software implementations of crypto toolbox for LE Secure Connection 693 // TODO: replace with code to use AES Engine of HCI Controller 694 typedef uint8_t sm_key24_t[3]; 695 typedef uint8_t sm_key56_t[7]; 696 typedef uint8_t sm_key256_t[32]; 697 698 #if 0 699 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 700 uint32_t rk[RKLENGTH(KEYBITS)]; 701 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 702 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 703 } 704 705 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 706 memcpy(k1, k0, 16); 707 sm_shift_left_by_one_bit_inplace(16, k1); 708 if (k0[0] & 0x80){ 709 k1[15] ^= 0x87; 710 } 711 memcpy(k2, k1, 16); 712 sm_shift_left_by_one_bit_inplace(16, k2); 713 if (k1[0] & 0x80){ 714 k2[15] ^= 0x87; 715 } 716 } 717 718 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 719 sm_key_t k0, k1, k2, zero; 720 memset(zero, 0, 16); 721 722 aes128_calc_cyphertext(key, zero, k0); 723 calc_subkeys(k0, k1, k2); 724 725 int cmac_block_count = (cmac_message_len + 15) / 16; 726 727 // step 3: .. 728 if (cmac_block_count==0){ 729 cmac_block_count = 1; 730 } 731 732 // step 4: set m_last 733 sm_key_t cmac_m_last; 734 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 735 int i; 736 if (sm_cmac_last_block_complete){ 737 for (i=0;i<16;i++){ 738 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 739 } 740 } else { 741 int valid_octets_in_last_block = cmac_message_len & 0x0f; 742 for (i=0;i<16;i++){ 743 if (i < valid_octets_in_last_block){ 744 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 745 continue; 746 } 747 if (i == valid_octets_in_last_block){ 748 cmac_m_last[i] = 0x80 ^ k2[i]; 749 continue; 750 } 751 cmac_m_last[i] = k2[i]; 752 } 753 } 754 755 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 756 // LOG_KEY(cmac_m_last); 757 758 // Step 5 759 sm_key_t cmac_x; 760 memset(cmac_x, 0, 16); 761 762 // Step 6 763 sm_key_t sm_cmac_y; 764 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 765 for (i=0;i<16;i++){ 766 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 767 } 768 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 769 } 770 for (i=0;i<16;i++){ 771 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 772 } 773 774 // Step 7 775 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 776 } 777 #endif 778 #endif 779 780 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){ 781 event[0] = type; 782 event[1] = event_size - 2; 783 little_endian_store_16(event, 2, con_handle); 784 event[4] = addr_type; 785 reverse_bd_addr(address, &event[5]); 786 } 787 788 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 789 UNUSED(channel); 790 791 // log event 792 hci_dump_packet(packet_type, 1, packet, size); 793 // dispatch to all event handlers 794 btstack_linked_list_iterator_t it; 795 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 796 while (btstack_linked_list_iterator_has_next(&it)){ 797 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 798 entry->callback(packet_type, 0, packet, size); 799 } 800 } 801 802 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 803 uint8_t event[11]; 804 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 805 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 806 } 807 808 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){ 809 uint8_t event[15]; 810 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 811 little_endian_store_32(event, 11, passkey); 812 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 813 } 814 815 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){ 816 // fetch addr and addr type from db 817 bd_addr_t identity_address; 818 int identity_address_type; 819 le_device_db_info(index, &identity_address_type, identity_address, NULL); 820 821 uint8_t event[19]; 822 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 823 event[11] = identity_address_type; 824 reverse_bd_addr(identity_address, &event[12]); 825 event[18] = index; 826 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 827 } 828 829 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 830 831 uint8_t event[18]; 832 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 833 event[11] = result; 834 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 835 } 836 837 // decide on stk generation based on 838 // - pairing request 839 // - io capabilities 840 // - OOB data availability 841 static void sm_setup_tk(void){ 842 843 // default: just works 844 setup->sm_stk_generation_method = JUST_WORKS; 845 846 #ifdef ENABLE_LE_SECURE_CONNECTIONS 847 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 848 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 849 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 850 memset(setup->sm_ra, 0, 16); 851 memset(setup->sm_rb, 0, 16); 852 #else 853 setup->sm_use_secure_connections = 0; 854 #endif 855 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 856 857 // If both devices have not set the MITM option in the Authentication Requirements 858 // Flags, then the IO capabilities shall be ignored and the Just Works association 859 // model shall be used. 860 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 861 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 862 log_info("SM: MITM not required by both -> JUST WORKS"); 863 return; 864 } 865 866 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 867 868 // If both devices have out of band authentication data, then the Authentication 869 // Requirements Flags shall be ignored when selecting the pairing method and the 870 // Out of Band pairing method shall be used. 871 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 872 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 873 log_info("SM: have OOB data"); 874 log_info_key("OOB", setup->sm_tk); 875 setup->sm_stk_generation_method = OOB; 876 return; 877 } 878 879 // Reset TK as it has been setup in sm_init_setup 880 sm_reset_tk(); 881 882 // Also use just works if unknown io capabilites 883 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)){ 884 return; 885 } 886 887 // Otherwise the IO capabilities of the devices shall be used to determine the 888 // pairing method as defined in Table 2.4. 889 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 890 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 891 892 #ifdef ENABLE_LE_SECURE_CONNECTIONS 893 // table not define by default 894 if (setup->sm_use_secure_connections){ 895 generation_method = stk_generation_method_with_secure_connection; 896 } 897 #endif 898 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)]; 899 900 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 901 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); 902 } 903 904 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 905 int flags = 0; 906 if (key_set & SM_KEYDIST_ENC_KEY){ 907 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 908 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 909 } 910 if (key_set & SM_KEYDIST_ID_KEY){ 911 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 912 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 913 } 914 if (key_set & SM_KEYDIST_SIGN){ 915 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 916 } 917 return flags; 918 } 919 920 static void sm_setup_key_distribution(uint8_t key_set){ 921 setup->sm_key_distribution_received_set = 0; 922 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 923 } 924 925 // CSRK Key Lookup 926 927 928 static int sm_address_resolution_idle(void){ 929 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 930 } 931 932 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){ 933 memcpy(sm_address_resolution_address, addr, 6); 934 sm_address_resolution_addr_type = addr_type; 935 sm_address_resolution_test = 0; 936 sm_address_resolution_mode = mode; 937 sm_address_resolution_context = context; 938 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 939 } 940 941 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 942 // check if already in list 943 btstack_linked_list_iterator_t it; 944 sm_lookup_entry_t * entry; 945 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 946 while(btstack_linked_list_iterator_has_next(&it)){ 947 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 948 if (entry->address_type != address_type) continue; 949 if (memcmp(entry->address, address, 6)) continue; 950 // already in list 951 return BTSTACK_BUSY; 952 } 953 entry = btstack_memory_sm_lookup_entry_get(); 954 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 955 entry->address_type = (bd_addr_type_t) address_type; 956 memcpy(entry->address, address, 6); 957 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 958 sm_run(); 959 return 0; 960 } 961 962 // 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 963 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 964 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 965 } 966 static inline void dkg_next_state(void){ 967 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 968 } 969 static inline void rau_next_state(void){ 970 rau_state = (random_address_update_t) (((int)rau_state) + 1); 971 } 972 973 // CMAC calculation using AES Engine 974 #ifdef ENABLE_CMAC_ENGINE 975 976 static inline void sm_cmac_next_state(void){ 977 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 978 } 979 980 static int sm_cmac_last_block_complete(void){ 981 if (sm_cmac_message_len == 0) return 0; 982 return (sm_cmac_message_len & 0x0f) == 0; 983 } 984 985 int sm_cmac_ready(void){ 986 return sm_cmac_state == CMAC_IDLE; 987 } 988 989 // generic cmac calculation 990 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])){ 991 // Generalized CMAC 992 memcpy(sm_cmac_k, key, 16); 993 memset(sm_cmac_x, 0, 16); 994 sm_cmac_block_current = 0; 995 sm_cmac_message_len = message_len; 996 sm_cmac_done_handler = done_callback; 997 sm_cmac_get_byte = get_byte_callback; 998 999 // step 2: n := ceil(len/const_Bsize); 1000 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 1001 1002 // step 3: .. 1003 if (sm_cmac_block_count==0){ 1004 sm_cmac_block_count = 1; 1005 } 1006 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 1007 1008 // first, we need to compute l for k1, k2, and m_last 1009 sm_cmac_state = CMAC_CALC_SUBKEYS; 1010 1011 // let's go 1012 sm_run(); 1013 } 1014 #endif 1015 1016 // cmac for ATT Message signing 1017 #ifdef ENABLE_LE_SIGNED_WRITE 1018 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 1019 if (offset >= sm_cmac_message_len) { 1020 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 1021 return 0; 1022 } 1023 1024 offset = sm_cmac_message_len - 1 - offset; 1025 1026 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 1027 if (offset < 3){ 1028 return sm_cmac_header[offset]; 1029 } 1030 int actual_message_len_incl_header = sm_cmac_message_len - 4; 1031 if (offset < actual_message_len_incl_header){ 1032 return sm_cmac_message[offset - 3]; 1033 } 1034 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 1035 } 1036 1037 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)){ 1038 // ATT Message Signing 1039 sm_cmac_header[0] = opcode; 1040 little_endian_store_16(sm_cmac_header, 1, con_handle); 1041 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 1042 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 1043 sm_cmac_message = message; 1044 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 1045 } 1046 #endif 1047 1048 #ifdef ENABLE_CMAC_ENGINE 1049 static void sm_cmac_handle_aes_engine_ready(void){ 1050 switch (sm_cmac_state){ 1051 case CMAC_CALC_SUBKEYS: { 1052 sm_key_t const_zero; 1053 memset(const_zero, 0, 16); 1054 sm_cmac_next_state(); 1055 sm_aes128_start(sm_cmac_k, const_zero, NULL); 1056 break; 1057 } 1058 case CMAC_CALC_MI: { 1059 int j; 1060 sm_key_t y; 1061 for (j=0;j<16;j++){ 1062 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 1063 } 1064 sm_cmac_block_current++; 1065 sm_cmac_next_state(); 1066 sm_aes128_start(sm_cmac_k, y, NULL); 1067 break; 1068 } 1069 case CMAC_CALC_MLAST: { 1070 int i; 1071 sm_key_t y; 1072 for (i=0;i<16;i++){ 1073 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1074 } 1075 log_info_key("Y", y); 1076 sm_cmac_block_current++; 1077 sm_cmac_next_state(); 1078 sm_aes128_start(sm_cmac_k, y, NULL); 1079 break; 1080 } 1081 default: 1082 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1083 break; 1084 } 1085 } 1086 1087 // CMAC Implementation using AES128 engine 1088 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1089 int i; 1090 int carry = 0; 1091 for (i=len-1; i >= 0 ; i--){ 1092 int new_carry = data[i] >> 7; 1093 data[i] = data[i] << 1 | carry; 1094 carry = new_carry; 1095 } 1096 } 1097 1098 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1099 switch (sm_cmac_state){ 1100 case CMAC_W4_SUBKEYS: { 1101 sm_key_t k1; 1102 memcpy(k1, data, 16); 1103 sm_shift_left_by_one_bit_inplace(16, k1); 1104 if (data[0] & 0x80){ 1105 k1[15] ^= 0x87; 1106 } 1107 sm_key_t k2; 1108 memcpy(k2, k1, 16); 1109 sm_shift_left_by_one_bit_inplace(16, k2); 1110 if (k1[0] & 0x80){ 1111 k2[15] ^= 0x87; 1112 } 1113 1114 log_info_key("k", sm_cmac_k); 1115 log_info_key("k1", k1); 1116 log_info_key("k2", k2); 1117 1118 // step 4: set m_last 1119 int i; 1120 if (sm_cmac_last_block_complete()){ 1121 for (i=0;i<16;i++){ 1122 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1123 } 1124 } else { 1125 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1126 for (i=0;i<16;i++){ 1127 if (i < valid_octets_in_last_block){ 1128 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1129 continue; 1130 } 1131 if (i == valid_octets_in_last_block){ 1132 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1133 continue; 1134 } 1135 sm_cmac_m_last[i] = k2[i]; 1136 } 1137 } 1138 1139 // next 1140 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1141 break; 1142 } 1143 case CMAC_W4_MI: 1144 memcpy(sm_cmac_x, data, 16); 1145 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1146 break; 1147 case CMAC_W4_MLAST: 1148 // done 1149 log_info("Setting CMAC Engine to IDLE"); 1150 sm_cmac_state = CMAC_IDLE; 1151 log_info_key("CMAC", data); 1152 sm_cmac_done_handler(data); 1153 break; 1154 default: 1155 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1156 break; 1157 } 1158 } 1159 #endif 1160 1161 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1162 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1163 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1164 switch (setup->sm_stk_generation_method){ 1165 case PK_RESP_INPUT: 1166 if (IS_RESPONDER(sm_conn->sm_role)){ 1167 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1168 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1169 } else { 1170 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)); 1171 } 1172 break; 1173 case PK_INIT_INPUT: 1174 if (IS_RESPONDER(sm_conn->sm_role)){ 1175 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)); 1176 } else { 1177 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1178 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1179 } 1180 break; 1181 case OK_BOTH_INPUT: 1182 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1183 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1184 break; 1185 case NK_BOTH_INPUT: 1186 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1187 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)); 1188 break; 1189 case JUST_WORKS: 1190 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1191 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1192 break; 1193 case OOB: 1194 // client already provided OOB data, let's skip notification. 1195 break; 1196 } 1197 } 1198 1199 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1200 int recv_flags; 1201 if (IS_RESPONDER(sm_conn->sm_role)){ 1202 // slave / responder 1203 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1204 } else { 1205 // master / initiator 1206 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1207 } 1208 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1209 return recv_flags == setup->sm_key_distribution_received_set; 1210 } 1211 1212 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1213 if (sm_active_connection_handle == con_handle){ 1214 sm_timeout_stop(); 1215 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1216 log_info("sm: connection 0x%x released setup context", con_handle); 1217 } 1218 } 1219 1220 static int sm_key_distribution_flags_for_auth_req(void){ 1221 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1222 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1223 // encryption information only if bonding requested 1224 flags |= SM_KEYDIST_ENC_KEY; 1225 } 1226 return flags; 1227 } 1228 1229 static void sm_reset_setup(void){ 1230 // fill in sm setup 1231 setup->sm_state_vars = 0; 1232 setup->sm_keypress_notification = 0xff; 1233 sm_reset_tk(); 1234 } 1235 1236 static void sm_init_setup(sm_connection_t * sm_conn){ 1237 1238 // fill in sm setup 1239 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1240 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1241 1242 // query client for OOB data 1243 int have_oob_data = 0; 1244 if (sm_get_oob_data) { 1245 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1246 } 1247 1248 sm_pairing_packet_t * local_packet; 1249 if (IS_RESPONDER(sm_conn->sm_role)){ 1250 // slave 1251 local_packet = &setup->sm_s_pres; 1252 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1253 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1254 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1255 } else { 1256 // master 1257 local_packet = &setup->sm_m_preq; 1258 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1259 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1260 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1261 1262 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1263 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1264 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1265 } 1266 1267 uint8_t auth_req = sm_auth_req; 1268 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1269 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1270 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1271 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1272 } 1273 1274 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1275 1276 sm_pairing_packet_t * remote_packet; 1277 int remote_key_request; 1278 if (IS_RESPONDER(sm_conn->sm_role)){ 1279 // slave / responder 1280 remote_packet = &setup->sm_m_preq; 1281 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1282 } else { 1283 // master / initiator 1284 remote_packet = &setup->sm_s_pres; 1285 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1286 } 1287 1288 // check key size 1289 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1290 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1291 1292 // decide on STK generation method 1293 sm_setup_tk(); 1294 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1295 1296 // check if STK generation method is acceptable by client 1297 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1298 1299 // identical to responder 1300 sm_setup_key_distribution(remote_key_request); 1301 1302 // JUST WORKS doens't provide authentication 1303 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1304 1305 return 0; 1306 } 1307 1308 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1309 1310 // cache and reset context 1311 int matched_device_id = sm_address_resolution_test; 1312 address_resolution_mode_t mode = sm_address_resolution_mode; 1313 void * context = sm_address_resolution_context; 1314 1315 // reset context 1316 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1317 sm_address_resolution_context = NULL; 1318 sm_address_resolution_test = -1; 1319 hci_con_handle_t con_handle = 0; 1320 1321 sm_connection_t * sm_connection; 1322 #ifdef ENABLE_LE_CENTRAL 1323 sm_key_t ltk; 1324 #endif 1325 switch (mode){ 1326 case ADDRESS_RESOLUTION_GENERAL: 1327 break; 1328 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1329 sm_connection = (sm_connection_t *) context; 1330 con_handle = sm_connection->sm_handle; 1331 switch (event){ 1332 case ADDRESS_RESOLUTION_SUCEEDED: 1333 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1334 sm_connection->sm_le_db_index = matched_device_id; 1335 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1336 if (sm_connection->sm_role) { 1337 // LTK request received before, IRK required -> start LTK calculation 1338 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1339 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1340 } 1341 break; 1342 } 1343 #ifdef ENABLE_LE_CENTRAL 1344 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1345 sm_connection->sm_security_request_received = 0; 1346 sm_connection->sm_bonding_requested = 0; 1347 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1348 if (!sm_is_null_key(ltk)){ 1349 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1350 } else { 1351 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1352 } 1353 #endif 1354 break; 1355 case ADDRESS_RESOLUTION_FAILED: 1356 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1357 if (sm_connection->sm_role) { 1358 // LTK request received before, IRK required -> negative LTK reply 1359 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1360 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1361 } 1362 break; 1363 } 1364 #ifdef ENABLE_LE_CENTRAL 1365 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1366 sm_connection->sm_security_request_received = 0; 1367 sm_connection->sm_bonding_requested = 0; 1368 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1369 #endif 1370 break; 1371 } 1372 break; 1373 default: 1374 break; 1375 } 1376 1377 switch (event){ 1378 case ADDRESS_RESOLUTION_SUCEEDED: 1379 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1380 break; 1381 case ADDRESS_RESOLUTION_FAILED: 1382 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1383 break; 1384 } 1385 } 1386 1387 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1388 1389 int le_db_index = -1; 1390 1391 // lookup device based on IRK 1392 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1393 int i; 1394 for (i=0; i < le_device_db_count(); i++){ 1395 sm_key_t irk; 1396 bd_addr_t address; 1397 int address_type; 1398 le_device_db_info(i, &address_type, address, irk); 1399 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1400 log_info("sm: device found for IRK, updating"); 1401 le_db_index = i; 1402 break; 1403 } 1404 } 1405 } 1406 1407 // if not found, lookup via public address if possible 1408 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1409 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1410 int i; 1411 for (i=0; i < le_device_db_count(); i++){ 1412 bd_addr_t address; 1413 int address_type; 1414 le_device_db_info(i, &address_type, address, NULL); 1415 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1416 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1417 log_info("sm: device found for public address, updating"); 1418 le_db_index = i; 1419 break; 1420 } 1421 } 1422 } 1423 1424 // if not found, add to db 1425 if (le_db_index < 0) { 1426 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1427 } 1428 1429 if (le_db_index >= 0){ 1430 1431 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1432 1433 #ifdef ENABLE_LE_SIGNED_WRITE 1434 // store local CSRK 1435 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1436 log_info("sm: store local CSRK"); 1437 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1438 le_device_db_local_counter_set(le_db_index, 0); 1439 } 1440 1441 // store remote CSRK 1442 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1443 log_info("sm: store remote CSRK"); 1444 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1445 le_device_db_remote_counter_set(le_db_index, 0); 1446 } 1447 #endif 1448 // store encryption information for secure connections: LTK generated by ECDH 1449 if (setup->sm_use_secure_connections){ 1450 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1451 uint8_t zero_rand[8]; 1452 memset(zero_rand, 0, 8); 1453 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1454 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1455 } 1456 1457 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1458 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1459 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1460 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1461 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1462 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1463 1464 } 1465 } 1466 1467 // keep le_db_index 1468 sm_conn->sm_le_db_index = le_db_index; 1469 } 1470 1471 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1472 setup->sm_pairing_failed_reason = reason; 1473 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1474 } 1475 1476 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1477 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1478 } 1479 1480 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1481 1482 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1483 static int sm_passkey_used(stk_generation_method_t method); 1484 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1485 1486 static void sm_log_ec_keypair(void){ 1487 log_info("Elliptic curve: X"); 1488 log_info_hexdump(&ec_q[0],32); 1489 log_info("Elliptic curve: Y"); 1490 log_info_hexdump(&ec_q[32],32); 1491 } 1492 1493 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1494 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1495 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1496 } else { 1497 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1498 } 1499 } 1500 1501 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1502 if (IS_RESPONDER(sm_conn->sm_role)){ 1503 // Responder 1504 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1505 } else { 1506 // Initiator role 1507 switch (setup->sm_stk_generation_method){ 1508 case JUST_WORKS: 1509 sm_sc_prepare_dhkey_check(sm_conn); 1510 break; 1511 1512 case NK_BOTH_INPUT: 1513 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1514 break; 1515 case PK_INIT_INPUT: 1516 case PK_RESP_INPUT: 1517 case OK_BOTH_INPUT: 1518 if (setup->sm_passkey_bit < 20) { 1519 sm_sc_start_calculating_local_confirm(sm_conn); 1520 } else { 1521 sm_sc_prepare_dhkey_check(sm_conn); 1522 } 1523 break; 1524 case OOB: 1525 // TODO: implement SC OOB 1526 break; 1527 } 1528 } 1529 } 1530 1531 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1532 return sm_cmac_sc_buffer[offset]; 1533 } 1534 1535 static void sm_sc_cmac_done(uint8_t * hash){ 1536 log_info("sm_sc_cmac_done: "); 1537 log_info_hexdump(hash, 16); 1538 1539 sm_connection_t * sm_conn = sm_cmac_connection; 1540 sm_cmac_connection = NULL; 1541 #ifdef ENABLE_CLASSIC 1542 link_key_type_t link_key_type; 1543 #endif 1544 1545 switch (sm_conn->sm_engine_state){ 1546 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1547 memcpy(setup->sm_local_confirm, hash, 16); 1548 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1549 break; 1550 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1551 // check 1552 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1553 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1554 break; 1555 } 1556 sm_sc_state_after_receiving_random(sm_conn); 1557 break; 1558 case SM_SC_W4_CALCULATE_G2: { 1559 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1560 big_endian_store_32(setup->sm_tk, 12, vab); 1561 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1562 sm_trigger_user_response(sm_conn); 1563 break; 1564 } 1565 case SM_SC_W4_CALCULATE_F5_SALT: 1566 memcpy(setup->sm_t, hash, 16); 1567 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1568 break; 1569 case SM_SC_W4_CALCULATE_F5_MACKEY: 1570 memcpy(setup->sm_mackey, hash, 16); 1571 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1572 break; 1573 case SM_SC_W4_CALCULATE_F5_LTK: 1574 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1575 // Errata Service Release to the Bluetooth Specification: ESR09 1576 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1577 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1578 memcpy(setup->sm_ltk, hash, 16); 1579 memcpy(setup->sm_local_ltk, hash, 16); 1580 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1581 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1582 break; 1583 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1584 memcpy(setup->sm_local_dhkey_check, hash, 16); 1585 if (IS_RESPONDER(sm_conn->sm_role)){ 1586 // responder 1587 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1588 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1589 } else { 1590 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1591 } 1592 } else { 1593 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1594 } 1595 break; 1596 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1597 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1598 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1599 break; 1600 } 1601 if (IS_RESPONDER(sm_conn->sm_role)){ 1602 // responder 1603 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1604 } else { 1605 // initiator 1606 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1607 } 1608 break; 1609 case SM_SC_W4_CALCULATE_H6_ILK: 1610 memcpy(setup->sm_t, hash, 16); 1611 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1612 break; 1613 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1614 #ifdef ENABLE_CLASSIC 1615 reverse_128(hash, setup->sm_t); 1616 link_key_type = sm_conn->sm_connection_authenticated ? 1617 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1618 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1619 if (IS_RESPONDER(sm_conn->sm_role)){ 1620 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1621 } else { 1622 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1623 } 1624 #endif 1625 if (IS_RESPONDER(sm_conn->sm_role)){ 1626 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1627 } else { 1628 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1629 } 1630 sm_done_for_handle(sm_conn->sm_handle); 1631 break; 1632 default: 1633 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1634 break; 1635 } 1636 sm_run(); 1637 } 1638 1639 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){ 1640 const uint16_t message_len = 65; 1641 sm_cmac_connection = sm_conn; 1642 memcpy(sm_cmac_sc_buffer, u, 32); 1643 memcpy(sm_cmac_sc_buffer+32, v, 32); 1644 sm_cmac_sc_buffer[64] = z; 1645 log_info("f4 key"); 1646 log_info_hexdump(x, 16); 1647 log_info("f4 message"); 1648 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1649 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1650 } 1651 1652 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1653 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1654 static const uint8_t f5_length[] = { 0x01, 0x00}; 1655 1656 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1657 1658 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1659 memset(dhkey, 0, 32); 1660 1661 #ifdef USE_MICRO_ECC_FOR_ECDH 1662 #if uECC_SUPPORTS_secp256r1 1663 // standard version 1664 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1()); 1665 #else 1666 // static version 1667 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1668 #endif 1669 #endif 1670 1671 #ifdef USE_MBEDTLS_FOR_ECDH 1672 // da * Pb 1673 mbedtls_mpi d; 1674 mbedtls_ecp_point Q; 1675 mbedtls_ecp_point DH; 1676 mbedtls_mpi_init(&d); 1677 mbedtls_ecp_point_init(&Q); 1678 mbedtls_ecp_point_init(&DH); 1679 mbedtls_mpi_read_binary(&d, ec_d, 32); 1680 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); 1681 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 1682 mbedtls_mpi_lset(&Q.Z, 1); 1683 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1684 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1685 mbedtls_ecp_point_free(&DH); 1686 mbedtls_mpi_free(&d); 1687 mbedtls_ecp_point_free(&Q); 1688 #endif 1689 1690 log_info("dhkey"); 1691 log_info_hexdump(dhkey, 32); 1692 } 1693 #endif 1694 1695 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1696 // calculate salt for f5 1697 const uint16_t message_len = 32; 1698 sm_cmac_connection = sm_conn; 1699 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1700 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1701 } 1702 1703 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){ 1704 const uint16_t message_len = 53; 1705 sm_cmac_connection = sm_conn; 1706 1707 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1708 sm_cmac_sc_buffer[0] = 0; 1709 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1710 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1711 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1712 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1713 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1714 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1715 log_info("f5 key"); 1716 log_info_hexdump(t, 16); 1717 log_info("f5 message for MacKey"); 1718 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1719 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1720 } 1721 1722 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1723 sm_key56_t bd_addr_master, bd_addr_slave; 1724 bd_addr_master[0] = setup->sm_m_addr_type; 1725 bd_addr_slave[0] = setup->sm_s_addr_type; 1726 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1727 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1728 if (IS_RESPONDER(sm_conn->sm_role)){ 1729 // responder 1730 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1731 } else { 1732 // initiator 1733 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1734 } 1735 } 1736 1737 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1738 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1739 const uint16_t message_len = 53; 1740 sm_cmac_connection = sm_conn; 1741 sm_cmac_sc_buffer[0] = 1; 1742 // 1..52 setup before 1743 log_info("f5 key"); 1744 log_info_hexdump(t, 16); 1745 log_info("f5 message for LTK"); 1746 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1747 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1748 } 1749 1750 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1751 f5_ltk(sm_conn, setup->sm_t); 1752 } 1753 1754 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){ 1755 const uint16_t message_len = 65; 1756 sm_cmac_connection = sm_conn; 1757 memcpy(sm_cmac_sc_buffer, n1, 16); 1758 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1759 memcpy(sm_cmac_sc_buffer+32, r, 16); 1760 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1761 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1762 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1763 log_info("f6 key"); 1764 log_info_hexdump(w, 16); 1765 log_info("f6 message"); 1766 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1767 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1768 } 1769 1770 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1771 // - U is 256 bits 1772 // - V is 256 bits 1773 // - X is 128 bits 1774 // - Y is 128 bits 1775 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){ 1776 const uint16_t message_len = 80; 1777 sm_cmac_connection = sm_conn; 1778 memcpy(sm_cmac_sc_buffer, u, 32); 1779 memcpy(sm_cmac_sc_buffer+32, v, 32); 1780 memcpy(sm_cmac_sc_buffer+64, y, 16); 1781 log_info("g2 key"); 1782 log_info_hexdump(x, 16); 1783 log_info("g2 message"); 1784 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1785 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1786 } 1787 1788 static void g2_calculate(sm_connection_t * sm_conn) { 1789 // calc Va if numeric comparison 1790 if (IS_RESPONDER(sm_conn->sm_role)){ 1791 // responder 1792 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1793 } else { 1794 // initiator 1795 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1796 } 1797 } 1798 1799 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1800 uint8_t z = 0; 1801 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1802 // some form of passkey 1803 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1804 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1805 setup->sm_passkey_bit++; 1806 } 1807 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1808 } 1809 1810 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1811 uint8_t z = 0; 1812 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1813 // some form of passkey 1814 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1815 // sm_passkey_bit was increased before sending confirm value 1816 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1817 } 1818 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1819 } 1820 1821 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1822 1823 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1824 // calculate DHKEY 1825 sm_sc_calculate_dhkey(setup->sm_dhkey); 1826 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1827 #endif 1828 1829 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1830 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1831 return; 1832 } else { 1833 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1834 } 1835 1836 } 1837 1838 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1839 // calculate DHKCheck 1840 sm_key56_t bd_addr_master, bd_addr_slave; 1841 bd_addr_master[0] = setup->sm_m_addr_type; 1842 bd_addr_slave[0] = setup->sm_s_addr_type; 1843 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1844 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1845 uint8_t iocap_a[3]; 1846 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1847 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1848 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1849 uint8_t iocap_b[3]; 1850 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1851 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1852 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1853 if (IS_RESPONDER(sm_conn->sm_role)){ 1854 // responder 1855 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); 1856 } else { 1857 // initiator 1858 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); 1859 } 1860 } 1861 1862 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1863 // validate E = f6() 1864 sm_key56_t bd_addr_master, bd_addr_slave; 1865 bd_addr_master[0] = setup->sm_m_addr_type; 1866 bd_addr_slave[0] = setup->sm_s_addr_type; 1867 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1868 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1869 1870 uint8_t iocap_a[3]; 1871 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1872 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1873 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1874 uint8_t iocap_b[3]; 1875 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1876 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1877 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1878 if (IS_RESPONDER(sm_conn->sm_role)){ 1879 // responder 1880 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); 1881 } else { 1882 // initiator 1883 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); 1884 } 1885 } 1886 1887 1888 // 1889 // Link Key Conversion Function h6 1890 // 1891 // h6(W, keyID) = AES-CMACW(keyID) 1892 // - W is 128 bits 1893 // - keyID is 32 bits 1894 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1895 const uint16_t message_len = 4; 1896 sm_cmac_connection = sm_conn; 1897 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1898 log_info("h6 key"); 1899 log_info_hexdump(w, 16); 1900 log_info("h6 message"); 1901 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1902 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1903 } 1904 1905 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1906 // Errata Service Release to the Bluetooth Specification: ESR09 1907 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1908 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1909 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1910 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1911 } 1912 1913 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1914 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1915 } 1916 1917 #endif 1918 1919 // key management legacy connections: 1920 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1921 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1922 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1923 // - responder reconnects: responder uses LTK receveived from master 1924 1925 // key management secure connections: 1926 // - both devices store same LTK from ECDH key exchange. 1927 1928 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1929 static void sm_load_security_info(sm_connection_t * sm_connection){ 1930 int encryption_key_size; 1931 int authenticated; 1932 int authorized; 1933 1934 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1935 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1936 &encryption_key_size, &authenticated, &authorized); 1937 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1938 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1939 sm_connection->sm_connection_authenticated = authenticated; 1940 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1941 } 1942 #endif 1943 1944 #ifdef ENABLE_LE_PERIPHERAL 1945 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1946 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1947 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1948 // re-establish used key encryption size 1949 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1950 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1951 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1952 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1953 log_info("sm: received ltk request with key size %u, authenticated %u", 1954 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1955 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1956 } 1957 #endif 1958 1959 static void sm_run(void){ 1960 1961 btstack_linked_list_iterator_t it; 1962 1963 // assert that stack has already bootet 1964 if (hci_get_state() != HCI_STATE_WORKING) return; 1965 1966 // assert that we can send at least commands 1967 if (!hci_can_send_command_packet_now()) return; 1968 1969 // 1970 // non-connection related behaviour 1971 // 1972 1973 // distributed key generation 1974 switch (dkg_state){ 1975 case DKG_CALC_IRK: 1976 // already busy? 1977 if (sm_aes128_state == SM_AES128_IDLE) { 1978 // IRK = d1(IR, 1, 0) 1979 sm_key_t d1_prime; 1980 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1981 dkg_next_state(); 1982 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1983 return; 1984 } 1985 break; 1986 case DKG_CALC_DHK: 1987 // already busy? 1988 if (sm_aes128_state == SM_AES128_IDLE) { 1989 // DHK = d1(IR, 3, 0) 1990 sm_key_t d1_prime; 1991 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1992 dkg_next_state(); 1993 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1994 return; 1995 } 1996 break; 1997 default: 1998 break; 1999 } 2000 2001 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2002 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2003 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 2004 sm_random_start(NULL); 2005 #else 2006 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 2007 hci_send_cmd(&hci_le_read_local_p256_public_key); 2008 #endif 2009 return; 2010 } 2011 #endif 2012 2013 // random address updates 2014 switch (rau_state){ 2015 case RAU_GET_RANDOM: 2016 rau_next_state(); 2017 sm_random_start(NULL); 2018 return; 2019 case RAU_GET_ENC: 2020 // already busy? 2021 if (sm_aes128_state == SM_AES128_IDLE) { 2022 sm_key_t r_prime; 2023 sm_ah_r_prime(sm_random_address, r_prime); 2024 rau_next_state(); 2025 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 2026 return; 2027 } 2028 break; 2029 case RAU_SET_ADDRESS: 2030 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2031 rau_state = RAU_IDLE; 2032 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2033 return; 2034 default: 2035 break; 2036 } 2037 2038 #ifdef ENABLE_CMAC_ENGINE 2039 // CMAC 2040 switch (sm_cmac_state){ 2041 case CMAC_CALC_SUBKEYS: 2042 case CMAC_CALC_MI: 2043 case CMAC_CALC_MLAST: 2044 // already busy? 2045 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2046 sm_cmac_handle_aes_engine_ready(); 2047 return; 2048 default: 2049 break; 2050 } 2051 #endif 2052 2053 // CSRK Lookup 2054 // -- if csrk lookup ready, find connection that require csrk lookup 2055 if (sm_address_resolution_idle()){ 2056 hci_connections_get_iterator(&it); 2057 while(btstack_linked_list_iterator_has_next(&it)){ 2058 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2059 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2060 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2061 // and start lookup 2062 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); 2063 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2064 break; 2065 } 2066 } 2067 } 2068 2069 // -- if csrk lookup ready, resolved addresses for received addresses 2070 if (sm_address_resolution_idle()) { 2071 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2072 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2073 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2074 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2075 btstack_memory_sm_lookup_entry_free(entry); 2076 } 2077 } 2078 2079 // -- Continue with CSRK device lookup by public or resolvable private address 2080 if (!sm_address_resolution_idle()){ 2081 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 2082 while (sm_address_resolution_test < le_device_db_count()){ 2083 int addr_type; 2084 bd_addr_t addr; 2085 sm_key_t irk; 2086 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2087 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2088 2089 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 2090 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2091 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2092 break; 2093 } 2094 2095 if (sm_address_resolution_addr_type == 0){ 2096 sm_address_resolution_test++; 2097 continue; 2098 } 2099 2100 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2101 2102 log_info("LE Device Lookup: calculate AH"); 2103 log_info_key("IRK", irk); 2104 2105 sm_key_t r_prime; 2106 sm_ah_r_prime(sm_address_resolution_address, r_prime); 2107 sm_address_resolution_ah_calculation_active = 1; 2108 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 2109 return; 2110 } 2111 2112 if (sm_address_resolution_test >= le_device_db_count()){ 2113 log_info("LE Device Lookup: not found"); 2114 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2115 } 2116 } 2117 2118 // handle basic actions that don't requires the full context 2119 hci_connections_get_iterator(&it); 2120 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2121 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2122 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2123 switch(sm_connection->sm_engine_state){ 2124 // responder side 2125 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2126 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2127 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2128 return; 2129 2130 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2131 case SM_SC_RECEIVED_LTK_REQUEST: 2132 switch (sm_connection->sm_irk_lookup_state){ 2133 case IRK_LOOKUP_FAILED: 2134 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2135 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2136 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2137 return; 2138 default: 2139 break; 2140 } 2141 break; 2142 #endif 2143 default: 2144 break; 2145 } 2146 } 2147 2148 // 2149 // active connection handling 2150 // -- use loop to handle next connection if lock on setup context is released 2151 2152 while (1) { 2153 2154 // Find connections that requires setup context and make active if no other is locked 2155 hci_connections_get_iterator(&it); 2156 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2157 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2158 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2159 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2160 int done = 1; 2161 int err; 2162 UNUSED(err); 2163 switch (sm_connection->sm_engine_state) { 2164 #ifdef ENABLE_LE_PERIPHERAL 2165 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2166 // send packet if possible, 2167 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2168 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2169 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2170 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2171 } else { 2172 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2173 } 2174 // don't lock sxetup context yet 2175 done = 0; 2176 break; 2177 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2178 sm_reset_setup(); 2179 sm_init_setup(sm_connection); 2180 // recover pairing request 2181 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2182 err = sm_stk_generation_init(sm_connection); 2183 if (err){ 2184 setup->sm_pairing_failed_reason = err; 2185 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2186 break; 2187 } 2188 sm_timeout_start(sm_connection); 2189 // generate random number first, if we need to show passkey 2190 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2191 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2192 break; 2193 } 2194 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2195 break; 2196 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2197 sm_reset_setup(); 2198 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2199 break; 2200 #endif 2201 #ifdef ENABLE_LE_CENTRAL 2202 case SM_INITIATOR_PH0_HAS_LTK: 2203 sm_reset_setup(); 2204 sm_load_security_info(sm_connection); 2205 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2206 break; 2207 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2208 sm_reset_setup(); 2209 sm_init_setup(sm_connection); 2210 sm_timeout_start(sm_connection); 2211 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2212 break; 2213 #endif 2214 2215 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2216 case SM_SC_RECEIVED_LTK_REQUEST: 2217 switch (sm_connection->sm_irk_lookup_state){ 2218 case IRK_LOOKUP_SUCCEEDED: 2219 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2220 // start using context by loading security info 2221 sm_reset_setup(); 2222 sm_load_security_info(sm_connection); 2223 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2224 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2225 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2226 break; 2227 } 2228 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2229 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2230 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2231 // don't lock setup context yet 2232 return; 2233 default: 2234 // just wait until IRK lookup is completed 2235 // don't lock setup context yet 2236 done = 0; 2237 break; 2238 } 2239 break; 2240 #endif 2241 default: 2242 done = 0; 2243 break; 2244 } 2245 if (done){ 2246 sm_active_connection_handle = sm_connection->sm_handle; 2247 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); 2248 } 2249 } 2250 2251 // 2252 // active connection handling 2253 // 2254 2255 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2256 2257 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2258 if (!connection) { 2259 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2260 return; 2261 } 2262 2263 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2264 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_NEEDED){ 2265 setup->sm_state_vars &= ~SM_STATE_VAR_DHKEY_NEEDED; 2266 hci_send_cmd(&hci_le_generate_dhkey, &setup->sm_peer_q[0], &setup->sm_peer_q[32]); 2267 return; 2268 } 2269 #endif 2270 2271 // assert that we could send a SM PDU - not needed for all of the following 2272 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2273 log_info("cannot send now, requesting can send now event"); 2274 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2275 return; 2276 } 2277 2278 // send keypress notifications 2279 if (setup->sm_keypress_notification != 0xff){ 2280 uint8_t buffer[2]; 2281 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2282 buffer[1] = setup->sm_keypress_notification; 2283 setup->sm_keypress_notification = 0xff; 2284 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2285 return; 2286 } 2287 2288 sm_key_t plaintext; 2289 int key_distribution_flags; 2290 UNUSED(key_distribution_flags); 2291 2292 log_info("sm_run: state %u", connection->sm_engine_state); 2293 2294 switch (connection->sm_engine_state){ 2295 2296 // general 2297 case SM_GENERAL_SEND_PAIRING_FAILED: { 2298 uint8_t buffer[2]; 2299 buffer[0] = SM_CODE_PAIRING_FAILED; 2300 buffer[1] = setup->sm_pairing_failed_reason; 2301 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2302 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2303 sm_done_for_handle(connection->sm_handle); 2304 break; 2305 } 2306 2307 // responding state 2308 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2309 case SM_SC_W2_GET_RANDOM_A: 2310 sm_random_start(connection); 2311 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2312 break; 2313 case SM_SC_W2_GET_RANDOM_B: 2314 sm_random_start(connection); 2315 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2316 break; 2317 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2318 if (!sm_cmac_ready()) break; 2319 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2320 sm_sc_calculate_local_confirm(connection); 2321 break; 2322 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2323 if (!sm_cmac_ready()) break; 2324 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2325 sm_sc_calculate_remote_confirm(connection); 2326 break; 2327 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2328 if (!sm_cmac_ready()) break; 2329 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2330 sm_sc_calculate_f6_for_dhkey_check(connection); 2331 break; 2332 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2333 if (!sm_cmac_ready()) break; 2334 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2335 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2336 break; 2337 case SM_SC_W2_CALCULATE_F5_SALT: 2338 if (!sm_cmac_ready()) break; 2339 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2340 f5_calculate_salt(connection); 2341 break; 2342 case SM_SC_W2_CALCULATE_F5_MACKEY: 2343 if (!sm_cmac_ready()) break; 2344 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2345 f5_calculate_mackey(connection); 2346 break; 2347 case SM_SC_W2_CALCULATE_F5_LTK: 2348 if (!sm_cmac_ready()) break; 2349 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2350 f5_calculate_ltk(connection); 2351 break; 2352 case SM_SC_W2_CALCULATE_G2: 2353 if (!sm_cmac_ready()) break; 2354 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2355 g2_calculate(connection); 2356 break; 2357 case SM_SC_W2_CALCULATE_H6_ILK: 2358 if (!sm_cmac_ready()) break; 2359 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2360 h6_calculate_ilk(connection); 2361 break; 2362 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2363 if (!sm_cmac_ready()) break; 2364 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2365 h6_calculate_br_edr_link_key(connection); 2366 break; 2367 #endif 2368 2369 #ifdef ENABLE_LE_CENTRAL 2370 // initiator side 2371 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2372 sm_key_t peer_ltk_flipped; 2373 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2374 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2375 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2376 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2377 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2378 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2379 return; 2380 } 2381 2382 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2383 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2384 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2385 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2386 sm_timeout_reset(connection); 2387 break; 2388 #endif 2389 2390 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2391 2392 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2393 uint8_t buffer[65]; 2394 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2395 // 2396 reverse_256(&ec_q[0], &buffer[1]); 2397 reverse_256(&ec_q[32], &buffer[33]); 2398 2399 // stk generation method 2400 // passkey entry: notify app to show passkey or to request passkey 2401 switch (setup->sm_stk_generation_method){ 2402 case JUST_WORKS: 2403 case NK_BOTH_INPUT: 2404 if (IS_RESPONDER(connection->sm_role)){ 2405 // responder 2406 sm_sc_start_calculating_local_confirm(connection); 2407 } else { 2408 // initiator 2409 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2410 } 2411 break; 2412 case PK_INIT_INPUT: 2413 case PK_RESP_INPUT: 2414 case OK_BOTH_INPUT: 2415 // use random TK for display 2416 memcpy(setup->sm_ra, setup->sm_tk, 16); 2417 memcpy(setup->sm_rb, setup->sm_tk, 16); 2418 setup->sm_passkey_bit = 0; 2419 2420 if (IS_RESPONDER(connection->sm_role)){ 2421 // responder 2422 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2423 } else { 2424 // initiator 2425 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2426 } 2427 sm_trigger_user_response(connection); 2428 break; 2429 case OOB: 2430 // TODO: implement SC OOB 2431 break; 2432 } 2433 2434 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2435 sm_timeout_reset(connection); 2436 break; 2437 } 2438 case SM_SC_SEND_CONFIRMATION: { 2439 uint8_t buffer[17]; 2440 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2441 reverse_128(setup->sm_local_confirm, &buffer[1]); 2442 if (IS_RESPONDER(connection->sm_role)){ 2443 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2444 } else { 2445 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2446 } 2447 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2448 sm_timeout_reset(connection); 2449 break; 2450 } 2451 case SM_SC_SEND_PAIRING_RANDOM: { 2452 uint8_t buffer[17]; 2453 buffer[0] = SM_CODE_PAIRING_RANDOM; 2454 reverse_128(setup->sm_local_nonce, &buffer[1]); 2455 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2456 if (IS_RESPONDER(connection->sm_role)){ 2457 // responder 2458 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2459 } else { 2460 // initiator 2461 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2462 } 2463 } else { 2464 if (IS_RESPONDER(connection->sm_role)){ 2465 // responder 2466 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2467 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2468 } else { 2469 sm_sc_prepare_dhkey_check(connection); 2470 } 2471 } else { 2472 // initiator 2473 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2474 } 2475 } 2476 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2477 sm_timeout_reset(connection); 2478 break; 2479 } 2480 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2481 uint8_t buffer[17]; 2482 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2483 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2484 2485 if (IS_RESPONDER(connection->sm_role)){ 2486 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2487 } else { 2488 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2489 } 2490 2491 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2492 sm_timeout_reset(connection); 2493 break; 2494 } 2495 2496 #endif 2497 2498 #ifdef ENABLE_LE_PERIPHERAL 2499 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2500 // echo initiator for now 2501 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2502 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2503 2504 if (setup->sm_use_secure_connections){ 2505 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2506 // skip LTK/EDIV for SC 2507 log_info("sm: dropping encryption information flag"); 2508 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2509 } else { 2510 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2511 } 2512 2513 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); 2514 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); 2515 // update key distribution after ENC was dropped 2516 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2517 2518 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2519 sm_timeout_reset(connection); 2520 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2521 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2522 sm_trigger_user_response(connection); 2523 } 2524 return; 2525 #endif 2526 2527 case SM_PH2_SEND_PAIRING_RANDOM: { 2528 uint8_t buffer[17]; 2529 buffer[0] = SM_CODE_PAIRING_RANDOM; 2530 reverse_128(setup->sm_local_random, &buffer[1]); 2531 if (IS_RESPONDER(connection->sm_role)){ 2532 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2533 } else { 2534 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2535 } 2536 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2537 sm_timeout_reset(connection); 2538 break; 2539 } 2540 2541 case SM_PH2_GET_RANDOM_TK: 2542 case SM_PH2_C1_GET_RANDOM_A: 2543 case SM_PH2_C1_GET_RANDOM_B: 2544 case SM_PH3_GET_RANDOM: 2545 case SM_PH3_GET_DIV: 2546 sm_next_responding_state(connection); 2547 sm_random_start(connection); 2548 return; 2549 2550 case SM_PH2_C1_GET_ENC_B: 2551 case SM_PH2_C1_GET_ENC_D: 2552 // already busy? 2553 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2554 sm_next_responding_state(connection); 2555 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2556 return; 2557 2558 case SM_PH3_LTK_GET_ENC: 2559 case SM_RESPONDER_PH4_LTK_GET_ENC: 2560 // already busy? 2561 if (sm_aes128_state == SM_AES128_IDLE) { 2562 sm_key_t d_prime; 2563 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2564 sm_next_responding_state(connection); 2565 sm_aes128_start(sm_persistent_er, d_prime, connection); 2566 return; 2567 } 2568 break; 2569 2570 case SM_PH3_CSRK_GET_ENC: 2571 // already busy? 2572 if (sm_aes128_state == SM_AES128_IDLE) { 2573 sm_key_t d_prime; 2574 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2575 sm_next_responding_state(connection); 2576 sm_aes128_start(sm_persistent_er, d_prime, connection); 2577 return; 2578 } 2579 break; 2580 2581 case SM_PH2_C1_GET_ENC_C: 2582 // already busy? 2583 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2584 // calculate m_confirm using aes128 engine - step 1 2585 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); 2586 sm_next_responding_state(connection); 2587 sm_aes128_start(setup->sm_tk, plaintext, connection); 2588 break; 2589 case SM_PH2_C1_GET_ENC_A: 2590 // already busy? 2591 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2592 // calculate confirm using aes128 engine - step 1 2593 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); 2594 sm_next_responding_state(connection); 2595 sm_aes128_start(setup->sm_tk, plaintext, connection); 2596 break; 2597 case SM_PH2_CALC_STK: 2598 // already busy? 2599 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2600 // calculate STK 2601 if (IS_RESPONDER(connection->sm_role)){ 2602 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2603 } else { 2604 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2605 } 2606 sm_next_responding_state(connection); 2607 sm_aes128_start(setup->sm_tk, plaintext, connection); 2608 break; 2609 case SM_PH3_Y_GET_ENC: 2610 // already busy? 2611 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2612 // PH3B2 - calculate Y from - enc 2613 // Y = dm(DHK, Rand) 2614 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2615 sm_next_responding_state(connection); 2616 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2617 return; 2618 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2619 uint8_t buffer[17]; 2620 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2621 reverse_128(setup->sm_local_confirm, &buffer[1]); 2622 if (IS_RESPONDER(connection->sm_role)){ 2623 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2624 } else { 2625 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2626 } 2627 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2628 sm_timeout_reset(connection); 2629 return; 2630 } 2631 #ifdef ENABLE_LE_PERIPHERAL 2632 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2633 sm_key_t stk_flipped; 2634 reverse_128(setup->sm_ltk, stk_flipped); 2635 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2636 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2637 return; 2638 } 2639 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2640 sm_key_t ltk_flipped; 2641 reverse_128(setup->sm_ltk, ltk_flipped); 2642 connection->sm_engine_state = SM_RESPONDER_IDLE; 2643 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2644 sm_done_for_handle(connection->sm_handle); 2645 return; 2646 } 2647 case SM_RESPONDER_PH4_Y_GET_ENC: 2648 // already busy? 2649 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2650 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2651 // Y = dm(DHK, Rand) 2652 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2653 sm_next_responding_state(connection); 2654 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2655 return; 2656 #endif 2657 #ifdef ENABLE_LE_CENTRAL 2658 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2659 sm_key_t stk_flipped; 2660 reverse_128(setup->sm_ltk, stk_flipped); 2661 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2662 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2663 return; 2664 } 2665 #endif 2666 2667 case SM_PH3_DISTRIBUTE_KEYS: 2668 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2669 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2670 uint8_t buffer[17]; 2671 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2672 reverse_128(setup->sm_ltk, &buffer[1]); 2673 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2674 sm_timeout_reset(connection); 2675 return; 2676 } 2677 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2678 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2679 uint8_t buffer[11]; 2680 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2681 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2682 reverse_64(setup->sm_local_rand, &buffer[3]); 2683 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2684 sm_timeout_reset(connection); 2685 return; 2686 } 2687 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2688 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2689 uint8_t buffer[17]; 2690 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2691 reverse_128(sm_persistent_irk, &buffer[1]); 2692 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2693 sm_timeout_reset(connection); 2694 return; 2695 } 2696 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2697 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2698 bd_addr_t local_address; 2699 uint8_t buffer[8]; 2700 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2701 switch (gap_random_address_get_mode()){ 2702 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2703 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2704 // public or static random 2705 gap_le_get_own_address(&buffer[1], local_address); 2706 break; 2707 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2708 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2709 // fallback to public 2710 gap_local_bd_addr(local_address); 2711 buffer[1] = 0; 2712 break; 2713 } 2714 reverse_bd_addr(local_address, &buffer[2]); 2715 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2716 sm_timeout_reset(connection); 2717 return; 2718 } 2719 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2720 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2721 2722 // hack to reproduce test runs 2723 if (test_use_fixed_local_csrk){ 2724 memset(setup->sm_local_csrk, 0xcc, 16); 2725 } 2726 2727 uint8_t buffer[17]; 2728 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2729 reverse_128(setup->sm_local_csrk, &buffer[1]); 2730 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2731 sm_timeout_reset(connection); 2732 return; 2733 } 2734 2735 // keys are sent 2736 if (IS_RESPONDER(connection->sm_role)){ 2737 // slave -> receive master keys if any 2738 if (sm_key_distribution_all_received(connection)){ 2739 sm_key_distribution_handle_all_received(connection); 2740 connection->sm_engine_state = SM_RESPONDER_IDLE; 2741 sm_done_for_handle(connection->sm_handle); 2742 } else { 2743 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2744 } 2745 } else { 2746 // master -> all done 2747 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2748 sm_done_for_handle(connection->sm_handle); 2749 } 2750 break; 2751 2752 default: 2753 break; 2754 } 2755 2756 // check again if active connection was released 2757 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2758 } 2759 } 2760 2761 // note: aes engine is ready as we just got the aes result 2762 static void sm_handle_encryption_result(uint8_t * data){ 2763 2764 sm_aes128_state = SM_AES128_IDLE; 2765 2766 if (sm_address_resolution_ah_calculation_active){ 2767 sm_address_resolution_ah_calculation_active = 0; 2768 // compare calulated address against connecting device 2769 uint8_t hash[3]; 2770 reverse_24(data, hash); 2771 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2772 log_info("LE Device Lookup: matched resolvable private address"); 2773 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2774 return; 2775 } 2776 // no match, try next 2777 sm_address_resolution_test++; 2778 return; 2779 } 2780 2781 switch (dkg_state){ 2782 case DKG_W4_IRK: 2783 reverse_128(data, sm_persistent_irk); 2784 log_info_key("irk", sm_persistent_irk); 2785 dkg_next_state(); 2786 return; 2787 case DKG_W4_DHK: 2788 reverse_128(data, sm_persistent_dhk); 2789 log_info_key("dhk", sm_persistent_dhk); 2790 dkg_next_state(); 2791 // SM Init Finished 2792 return; 2793 default: 2794 break; 2795 } 2796 2797 switch (rau_state){ 2798 case RAU_W4_ENC: 2799 reverse_24(data, &sm_random_address[3]); 2800 rau_next_state(); 2801 return; 2802 default: 2803 break; 2804 } 2805 2806 #ifdef ENABLE_CMAC_ENGINE 2807 switch (sm_cmac_state){ 2808 case CMAC_W4_SUBKEYS: 2809 case CMAC_W4_MI: 2810 case CMAC_W4_MLAST: 2811 { 2812 sm_key_t t; 2813 reverse_128(data, t); 2814 sm_cmac_handle_encryption_result(t); 2815 } 2816 return; 2817 default: 2818 break; 2819 } 2820 #endif 2821 2822 // retrieve sm_connection provided to sm_aes128_start_encryption 2823 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2824 if (!connection) return; 2825 switch (connection->sm_engine_state){ 2826 case SM_PH2_C1_W4_ENC_A: 2827 case SM_PH2_C1_W4_ENC_C: 2828 { 2829 sm_key_t t2; 2830 reverse_128(data, t2); 2831 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2832 } 2833 sm_next_responding_state(connection); 2834 return; 2835 case SM_PH2_C1_W4_ENC_B: 2836 reverse_128(data, setup->sm_local_confirm); 2837 log_info_key("c1!", setup->sm_local_confirm); 2838 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2839 return; 2840 case SM_PH2_C1_W4_ENC_D: 2841 { 2842 sm_key_t peer_confirm_test; 2843 reverse_128(data, peer_confirm_test); 2844 log_info_key("c1!", peer_confirm_test); 2845 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2846 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2847 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2848 return; 2849 } 2850 if (IS_RESPONDER(connection->sm_role)){ 2851 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2852 } else { 2853 connection->sm_engine_state = SM_PH2_CALC_STK; 2854 } 2855 } 2856 return; 2857 case SM_PH2_W4_STK: 2858 reverse_128(data, setup->sm_ltk); 2859 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2860 log_info_key("stk", setup->sm_ltk); 2861 if (IS_RESPONDER(connection->sm_role)){ 2862 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2863 } else { 2864 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2865 } 2866 return; 2867 case SM_PH3_Y_W4_ENC:{ 2868 sm_key_t y128; 2869 reverse_128(data, y128); 2870 setup->sm_local_y = big_endian_read_16(y128, 14); 2871 log_info_hex16("y", setup->sm_local_y); 2872 // PH3B3 - calculate EDIV 2873 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2874 log_info_hex16("ediv", setup->sm_local_ediv); 2875 // PH3B4 - calculate LTK - enc 2876 // LTK = d1(ER, DIV, 0)) 2877 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2878 return; 2879 } 2880 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2881 sm_key_t y128; 2882 reverse_128(data, y128); 2883 setup->sm_local_y = big_endian_read_16(y128, 14); 2884 log_info_hex16("y", setup->sm_local_y); 2885 2886 // PH3B3 - calculate DIV 2887 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2888 log_info_hex16("ediv", setup->sm_local_ediv); 2889 // PH3B4 - calculate LTK - enc 2890 // LTK = d1(ER, DIV, 0)) 2891 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2892 return; 2893 } 2894 case SM_PH3_LTK_W4_ENC: 2895 reverse_128(data, setup->sm_ltk); 2896 log_info_key("ltk", setup->sm_ltk); 2897 // calc CSRK next 2898 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2899 return; 2900 case SM_PH3_CSRK_W4_ENC: 2901 reverse_128(data, setup->sm_local_csrk); 2902 log_info_key("csrk", setup->sm_local_csrk); 2903 if (setup->sm_key_distribution_send_set){ 2904 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2905 } else { 2906 // no keys to send, just continue 2907 if (IS_RESPONDER(connection->sm_role)){ 2908 // slave -> receive master keys 2909 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2910 } else { 2911 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2912 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2913 } else { 2914 // master -> all done 2915 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2916 sm_done_for_handle(connection->sm_handle); 2917 } 2918 } 2919 } 2920 return; 2921 #ifdef ENABLE_LE_PERIPHERAL 2922 case SM_RESPONDER_PH4_LTK_W4_ENC: 2923 reverse_128(data, setup->sm_ltk); 2924 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2925 log_info_key("ltk", setup->sm_ltk); 2926 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2927 return; 2928 #endif 2929 default: 2930 break; 2931 } 2932 } 2933 2934 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2935 2936 #if (defined(USE_MICRO_ECC_FOR_ECDH) && !defined(WICED_VERSION)) || defined(USE_MBEDTLS_FOR_ECDH) 2937 // @return OK 2938 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2939 if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; 2940 int offset = setup->sm_passkey_bit; 2941 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2942 while (size) { 2943 *buffer++ = setup->sm_peer_q[offset++]; 2944 size--; 2945 } 2946 setup->sm_passkey_bit = offset; 2947 return 1; 2948 } 2949 #endif 2950 #ifdef USE_MBEDTLS_FOR_ECDH 2951 // @return error - just wrap sm_generate_f_rng 2952 static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ 2953 UNUSED(context); 2954 return sm_generate_f_rng(buffer, size) == 0; 2955 } 2956 #endif /* USE_MBEDTLS_FOR_ECDH */ 2957 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2958 2959 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2960 static void sm_handle_random_result(uint8_t * data){ 2961 2962 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2963 2964 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2965 int num_bytes = setup->sm_passkey_bit; 2966 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 2967 num_bytes += 8; 2968 setup->sm_passkey_bit = num_bytes; 2969 2970 if (num_bytes >= 64){ 2971 2972 // init pre-generated random data from sm_peer_q 2973 setup->sm_passkey_bit = 0; 2974 2975 // generate EC key 2976 #ifdef USE_MICRO_ECC_FOR_ECDH 2977 2978 #ifndef WICED_VERSION 2979 log_info("set uECC RNG for initial key generation with 64 random bytes"); 2980 // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it 2981 uECC_set_rng(&sm_generate_f_rng); 2982 #endif /* WICED_VERSION */ 2983 2984 #if uECC_SUPPORTS_secp256r1 2985 // standard version 2986 uECC_make_key(ec_q, ec_d, uECC_secp256r1()); 2987 2988 // disable RNG again, as returning no randmon data lets shared key generation fail 2989 log_info("disable uECC RNG in standard version after key generation"); 2990 uECC_set_rng(NULL); 2991 #else 2992 // static version 2993 uECC_make_key(ec_q, ec_d); 2994 #endif 2995 #endif /* USE_MICRO_ECC_FOR_ECDH */ 2996 2997 #ifdef USE_MBEDTLS_FOR_ECDH 2998 mbedtls_mpi d; 2999 mbedtls_ecp_point P; 3000 mbedtls_mpi_init(&d); 3001 mbedtls_ecp_point_init(&P); 3002 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); 3003 log_info("gen keypair %x", res); 3004 mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); 3005 mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); 3006 mbedtls_mpi_write_binary(&d, ec_d, 32); 3007 mbedtls_ecp_point_free(&P); 3008 mbedtls_mpi_free(&d); 3009 #endif /* USE_MBEDTLS_FOR_ECDH */ 3010 3011 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3012 log_info("Elliptic curve: d"); 3013 log_info_hexdump(ec_d,32); 3014 sm_log_ec_keypair(); 3015 } 3016 } 3017 #endif 3018 3019 switch (rau_state){ 3020 case RAU_W4_RANDOM: 3021 // non-resolvable vs. resolvable 3022 switch (gap_random_adress_type){ 3023 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3024 // resolvable: use random as prand and calc address hash 3025 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3026 memcpy(sm_random_address, data, 3); 3027 sm_random_address[0] &= 0x3f; 3028 sm_random_address[0] |= 0x40; 3029 rau_state = RAU_GET_ENC; 3030 break; 3031 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3032 default: 3033 // "The two most significant bits of the address shall be equal to ‘0’"" 3034 memcpy(sm_random_address, data, 6); 3035 sm_random_address[0] &= 0x3f; 3036 rau_state = RAU_SET_ADDRESS; 3037 break; 3038 } 3039 return; 3040 default: 3041 break; 3042 } 3043 3044 // retrieve sm_connection provided to sm_random_start 3045 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 3046 if (!connection) return; 3047 switch (connection->sm_engine_state){ 3048 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3049 case SM_SC_W4_GET_RANDOM_A: 3050 memcpy(&setup->sm_local_nonce[0], data, 8); 3051 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 3052 break; 3053 case SM_SC_W4_GET_RANDOM_B: 3054 memcpy(&setup->sm_local_nonce[8], data, 8); 3055 // initiator & jw/nc -> send pairing random 3056 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3057 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3058 break; 3059 } else { 3060 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3061 } 3062 break; 3063 #endif 3064 3065 case SM_PH2_W4_RANDOM_TK: 3066 { 3067 sm_reset_tk(); 3068 uint32_t tk; 3069 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3070 // map random to 0-999999 without speding much cycles on a modulus operation 3071 tk = little_endian_read_32(data,0); 3072 tk = tk & 0xfffff; // 1048575 3073 if (tk >= 999999){ 3074 tk = tk - 999999; 3075 } 3076 } else { 3077 // override with pre-defined passkey 3078 tk = sm_fixed_passkey_in_display_role; 3079 } 3080 big_endian_store_32(setup->sm_tk, 12, tk); 3081 if (IS_RESPONDER(connection->sm_role)){ 3082 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3083 } else { 3084 if (setup->sm_use_secure_connections){ 3085 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3086 } else { 3087 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3088 sm_trigger_user_response(connection); 3089 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3090 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3091 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3092 } 3093 } 3094 } 3095 return; 3096 } 3097 case SM_PH2_C1_W4_RANDOM_A: 3098 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 3099 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 3100 return; 3101 case SM_PH2_C1_W4_RANDOM_B: 3102 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 3103 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3104 return; 3105 case SM_PH3_W4_RANDOM: 3106 reverse_64(data, setup->sm_local_rand); 3107 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3108 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 3109 // no db for authenticated flag hack: store flag in bit 4 of LSB 3110 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 3111 connection->sm_engine_state = SM_PH3_GET_DIV; 3112 return; 3113 case SM_PH3_W4_DIV: 3114 // use 16 bit from random value as div 3115 setup->sm_local_div = big_endian_read_16(data, 0); 3116 log_info_hex16("div", setup->sm_local_div); 3117 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3118 return; 3119 default: 3120 break; 3121 } 3122 } 3123 3124 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3125 3126 UNUSED(channel); // ok: there is no channel 3127 UNUSED(size); // ok: fixed format HCI events 3128 3129 sm_connection_t * sm_conn; 3130 hci_con_handle_t con_handle; 3131 3132 switch (packet_type) { 3133 3134 case HCI_EVENT_PACKET: 3135 switch (hci_event_packet_get_type(packet)) { 3136 3137 case BTSTACK_EVENT_STATE: 3138 // bt stack activated, get started 3139 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3140 log_info("HCI Working!"); 3141 3142 3143 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 3144 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3145 if (!sm_have_ec_keypair){ 3146 setup->sm_passkey_bit = 0; 3147 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3148 } 3149 #endif 3150 // trigger Random Address generation if requested before 3151 switch (gap_random_adress_type){ 3152 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3153 rau_state = RAU_IDLE; 3154 break; 3155 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 3156 rau_state = RAU_SET_ADDRESS; 3157 break; 3158 default: 3159 rau_state = RAU_GET_RANDOM; 3160 break; 3161 } 3162 sm_run(); 3163 } 3164 break; 3165 3166 case HCI_EVENT_LE_META: 3167 switch (packet[2]) { 3168 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3169 3170 log_info("sm: connected"); 3171 3172 if (packet[3]) return; // connection failed 3173 3174 con_handle = little_endian_read_16(packet, 4); 3175 sm_conn = sm_get_connection_for_handle(con_handle); 3176 if (!sm_conn) break; 3177 3178 sm_conn->sm_handle = con_handle; 3179 sm_conn->sm_role = packet[6]; 3180 sm_conn->sm_peer_addr_type = packet[7]; 3181 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3182 3183 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3184 3185 // reset security properties 3186 sm_conn->sm_connection_encrypted = 0; 3187 sm_conn->sm_connection_authenticated = 0; 3188 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3189 sm_conn->sm_le_db_index = -1; 3190 3191 // prepare CSRK lookup (does not involve setup) 3192 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3193 3194 // just connected -> everything else happens in sm_run() 3195 if (IS_RESPONDER(sm_conn->sm_role)){ 3196 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3197 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3198 if (sm_slave_request_security) { 3199 // request security if requested by app 3200 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3201 } else { 3202 // otherwise, wait for pairing request 3203 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3204 } 3205 } 3206 break; 3207 } else { 3208 // master 3209 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3210 } 3211 break; 3212 3213 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3214 con_handle = little_endian_read_16(packet, 3); 3215 sm_conn = sm_get_connection_for_handle(con_handle); 3216 if (!sm_conn) break; 3217 3218 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3219 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3220 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3221 break; 3222 } 3223 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3224 // PH2 SEND LTK as we need to exchange keys in PH3 3225 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3226 break; 3227 } 3228 3229 // store rand and ediv 3230 reverse_64(&packet[5], sm_conn->sm_local_rand); 3231 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3232 3233 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3234 // potentially stored LTK is from the master 3235 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3236 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3237 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3238 break; 3239 } 3240 // additionally check if remote is in LE Device DB if requested 3241 switch(sm_conn->sm_irk_lookup_state){ 3242 case IRK_LOOKUP_FAILED: 3243 log_info("LTK Request: device not in device db"); 3244 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3245 break; 3246 case IRK_LOOKUP_SUCCEEDED: 3247 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3248 break; 3249 default: 3250 // wait for irk look doen 3251 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3252 break; 3253 } 3254 break; 3255 } 3256 3257 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3258 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3259 #else 3260 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3261 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3262 #endif 3263 break; 3264 3265 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3266 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3267 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3268 log_error("Read Local P256 Public Key failed"); 3269 break; 3270 } 3271 3272 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3273 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3274 3275 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3276 sm_log_ec_keypair(); 3277 break; 3278 case HCI_SUBEVENT_LE_GENERATE_DHKEY_COMPLETE: 3279 sm_conn = sm_get_connection_for_handle(sm_active_connection_handle); 3280 if (hci_subevent_le_generate_dhkey_complete_get_status(packet)){ 3281 log_error("Generate DHKEY failed -> abort"); 3282 // abort pairing with 'unspecified reason' 3283 sm_pdu_received_in_wrong_state(sm_conn); 3284 break; 3285 } 3286 3287 hci_subevent_le_generate_dhkey_complete_get_dhkey(packet, &setup->sm_dhkey[0]); 3288 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 3289 log_info("dhkey"); 3290 log_info_hexdump(&setup->sm_dhkey[0], 32); 3291 3292 // trigger next step 3293 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 3294 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 3295 } 3296 break; 3297 #endif 3298 default: 3299 break; 3300 } 3301 break; 3302 3303 case HCI_EVENT_ENCRYPTION_CHANGE: 3304 con_handle = little_endian_read_16(packet, 3); 3305 sm_conn = sm_get_connection_for_handle(con_handle); 3306 if (!sm_conn) break; 3307 3308 sm_conn->sm_connection_encrypted = packet[5]; 3309 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3310 sm_conn->sm_actual_encryption_key_size); 3311 log_info("event handler, state %u", sm_conn->sm_engine_state); 3312 if (!sm_conn->sm_connection_encrypted) break; 3313 // continue if part of initial pairing 3314 switch (sm_conn->sm_engine_state){ 3315 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3316 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3317 sm_done_for_handle(sm_conn->sm_handle); 3318 break; 3319 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3320 if (IS_RESPONDER(sm_conn->sm_role)){ 3321 // slave 3322 if (setup->sm_use_secure_connections){ 3323 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3324 } else { 3325 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3326 } 3327 } else { 3328 // master 3329 if (sm_key_distribution_all_received(sm_conn)){ 3330 // skip receiving keys as there are none 3331 sm_key_distribution_handle_all_received(sm_conn); 3332 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3333 } else { 3334 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3335 } 3336 } 3337 break; 3338 default: 3339 break; 3340 } 3341 break; 3342 3343 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3344 con_handle = little_endian_read_16(packet, 3); 3345 sm_conn = sm_get_connection_for_handle(con_handle); 3346 if (!sm_conn) break; 3347 3348 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3349 log_info("event handler, state %u", sm_conn->sm_engine_state); 3350 // continue if part of initial pairing 3351 switch (sm_conn->sm_engine_state){ 3352 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3353 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3354 sm_done_for_handle(sm_conn->sm_handle); 3355 break; 3356 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3357 if (IS_RESPONDER(sm_conn->sm_role)){ 3358 // slave 3359 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3360 } else { 3361 // master 3362 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3363 } 3364 break; 3365 default: 3366 break; 3367 } 3368 break; 3369 3370 3371 case HCI_EVENT_DISCONNECTION_COMPLETE: 3372 con_handle = little_endian_read_16(packet, 3); 3373 sm_done_for_handle(con_handle); 3374 sm_conn = sm_get_connection_for_handle(con_handle); 3375 if (!sm_conn) break; 3376 3377 // delete stored bonding on disconnect with authentication failure in ph0 3378 if (sm_conn->sm_role == 0 3379 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3380 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3381 le_device_db_remove(sm_conn->sm_le_db_index); 3382 } 3383 3384 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3385 sm_conn->sm_handle = 0; 3386 break; 3387 3388 case HCI_EVENT_COMMAND_COMPLETE: 3389 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3390 sm_handle_encryption_result(&packet[6]); 3391 break; 3392 } 3393 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3394 sm_handle_random_result(&packet[6]); 3395 break; 3396 } 3397 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3398 // set local addr for le device db 3399 bd_addr_t addr; 3400 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3401 le_device_db_set_local_bd_addr(addr); 3402 } 3403 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_local_supported_commands)){ 3404 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3405 if ((packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE+1+34] & 0x06) != 0x06){ 3406 // mbedTLS can also be used if already available (and malloc is supported) 3407 log_error("LE Secure Connections enabled, but HCI Controller doesn't support it. Please add USE_MICRO_ECC_FOR_ECDH to btstack_config.h"); 3408 } 3409 #endif 3410 } 3411 break; 3412 default: 3413 break; 3414 } 3415 break; 3416 default: 3417 break; 3418 } 3419 3420 sm_run(); 3421 } 3422 3423 static inline int sm_calc_actual_encryption_key_size(int other){ 3424 if (other < sm_min_encryption_key_size) return 0; 3425 if (other < sm_max_encryption_key_size) return other; 3426 return sm_max_encryption_key_size; 3427 } 3428 3429 3430 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3431 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3432 switch (method){ 3433 case JUST_WORKS: 3434 case NK_BOTH_INPUT: 3435 return 1; 3436 default: 3437 return 0; 3438 } 3439 } 3440 // responder 3441 3442 static int sm_passkey_used(stk_generation_method_t method){ 3443 switch (method){ 3444 case PK_RESP_INPUT: 3445 return 1; 3446 default: 3447 return 0; 3448 } 3449 } 3450 #endif 3451 3452 /** 3453 * @return ok 3454 */ 3455 static int sm_validate_stk_generation_method(void){ 3456 // check if STK generation method is acceptable by client 3457 switch (setup->sm_stk_generation_method){ 3458 case JUST_WORKS: 3459 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3460 case PK_RESP_INPUT: 3461 case PK_INIT_INPUT: 3462 case OK_BOTH_INPUT: 3463 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3464 case OOB: 3465 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3466 case NK_BOTH_INPUT: 3467 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3468 return 1; 3469 default: 3470 return 0; 3471 } 3472 } 3473 3474 // size of complete sm_pdu used to validate input 3475 static const uint8_t sm_pdu_size[] = { 3476 0, // 0x00 invalid opcode 3477 7, // 0x01 pairing request 3478 7, // 0x02 pairing response 3479 17, // 0x03 pairing confirm 3480 17, // 0x04 pairing random 3481 2, // 0x05 pairing failed 3482 17, // 0x06 encryption information 3483 11, // 0x07 master identification 3484 17, // 0x08 identification information 3485 8, // 0x09 identify address information 3486 17, // 0x0a signing information 3487 2, // 0x0b security request 3488 65, // 0x0c pairing public key 3489 17, // 0x0d pairing dhk check 3490 2, // 0x0e keypress notification 3491 }; 3492 3493 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3494 3495 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3496 sm_run(); 3497 } 3498 3499 if (packet_type != SM_DATA_PACKET) return; 3500 if (size == 0) return; 3501 3502 uint8_t sm_pdu_code = packet[0]; 3503 3504 // validate pdu size 3505 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3506 if (sm_pdu_size[sm_pdu_code] != size) return; 3507 3508 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3509 if (!sm_conn) return; 3510 3511 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3512 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3513 return; 3514 } 3515 3516 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3517 3518 int err; 3519 UNUSED(err); 3520 3521 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3522 uint8_t buffer[5]; 3523 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3524 buffer[1] = 3; 3525 little_endian_store_16(buffer, 2, con_handle); 3526 buffer[4] = packet[1]; 3527 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3528 return; 3529 } 3530 3531 switch (sm_conn->sm_engine_state){ 3532 3533 // a sm timeout requries a new physical connection 3534 case SM_GENERAL_TIMEOUT: 3535 return; 3536 3537 #ifdef ENABLE_LE_CENTRAL 3538 3539 // Initiator 3540 case SM_INITIATOR_CONNECTED: 3541 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3542 sm_pdu_received_in_wrong_state(sm_conn); 3543 break; 3544 } 3545 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3546 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3547 break; 3548 } 3549 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3550 sm_key_t ltk; 3551 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3552 if (!sm_is_null_key(ltk)){ 3553 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3554 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3555 } else { 3556 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3557 } 3558 break; 3559 } 3560 // otherwise, store security request 3561 sm_conn->sm_security_request_received = 1; 3562 break; 3563 3564 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3565 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3566 sm_pdu_received_in_wrong_state(sm_conn); 3567 break; 3568 } 3569 // store pairing request 3570 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3571 err = sm_stk_generation_init(sm_conn); 3572 if (err){ 3573 setup->sm_pairing_failed_reason = err; 3574 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3575 break; 3576 } 3577 3578 // generate random number first, if we need to show passkey 3579 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3580 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3581 break; 3582 } 3583 3584 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3585 if (setup->sm_use_secure_connections){ 3586 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3587 if (setup->sm_stk_generation_method == JUST_WORKS){ 3588 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3589 sm_trigger_user_response(sm_conn); 3590 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3591 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3592 } 3593 } else { 3594 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3595 } 3596 break; 3597 } 3598 #endif 3599 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3600 sm_trigger_user_response(sm_conn); 3601 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3602 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3603 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3604 } 3605 break; 3606 3607 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3608 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3609 sm_pdu_received_in_wrong_state(sm_conn); 3610 break; 3611 } 3612 3613 // store s_confirm 3614 reverse_128(&packet[1], setup->sm_peer_confirm); 3615 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3616 break; 3617 3618 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3619 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3620 sm_pdu_received_in_wrong_state(sm_conn); 3621 break;; 3622 } 3623 3624 // received random value 3625 reverse_128(&packet[1], setup->sm_peer_random); 3626 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3627 break; 3628 #endif 3629 3630 #ifdef ENABLE_LE_PERIPHERAL 3631 // Responder 3632 case SM_RESPONDER_IDLE: 3633 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3634 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3635 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3636 sm_pdu_received_in_wrong_state(sm_conn); 3637 break;; 3638 } 3639 3640 // store pairing request 3641 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3642 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3643 break; 3644 #endif 3645 3646 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3647 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3648 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3649 sm_pdu_received_in_wrong_state(sm_conn); 3650 break; 3651 } 3652 3653 // store public key for DH Key calculation 3654 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3655 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3656 3657 // validate public key using micro-ecc 3658 err = 0; 3659 3660 #ifdef USE_MICRO_ECC_FOR_ECDH 3661 #if uECC_SUPPORTS_secp256r1 3662 // standard version 3663 err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0; 3664 #else 3665 // static version 3666 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3667 #endif 3668 #endif 3669 3670 #ifdef USE_MBEDTLS_FOR_ECDH 3671 mbedtls_ecp_point Q; 3672 mbedtls_ecp_point_init( &Q ); 3673 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); 3674 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 3675 mbedtls_mpi_lset(&Q.Z, 1); 3676 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3677 mbedtls_ecp_point_free( & Q); 3678 #endif 3679 3680 if (err){ 3681 log_error("sm: peer public key invalid %x", err); 3682 // uses "unspecified reason", there is no "public key invalid" error code 3683 sm_pdu_received_in_wrong_state(sm_conn); 3684 break; 3685 } 3686 3687 #ifndef USE_SOFTWARE_ECDH_IMPLEMENTATION 3688 // ask controller to calculate dhkey 3689 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_NEEDED; 3690 #endif 3691 3692 if (IS_RESPONDER(sm_conn->sm_role)){ 3693 // responder 3694 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3695 } else { 3696 // initiator 3697 // stk generation method 3698 // passkey entry: notify app to show passkey or to request passkey 3699 switch (setup->sm_stk_generation_method){ 3700 case JUST_WORKS: 3701 case NK_BOTH_INPUT: 3702 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3703 break; 3704 case PK_RESP_INPUT: 3705 sm_sc_start_calculating_local_confirm(sm_conn); 3706 break; 3707 case PK_INIT_INPUT: 3708 case OK_BOTH_INPUT: 3709 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3710 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3711 break; 3712 } 3713 sm_sc_start_calculating_local_confirm(sm_conn); 3714 break; 3715 case OOB: 3716 // TODO: implement SC OOB 3717 break; 3718 } 3719 } 3720 break; 3721 3722 case SM_SC_W4_CONFIRMATION: 3723 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3724 sm_pdu_received_in_wrong_state(sm_conn); 3725 break; 3726 } 3727 // received confirm value 3728 reverse_128(&packet[1], setup->sm_peer_confirm); 3729 3730 if (IS_RESPONDER(sm_conn->sm_role)){ 3731 // responder 3732 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3733 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3734 // still waiting for passkey 3735 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3736 break; 3737 } 3738 } 3739 sm_sc_start_calculating_local_confirm(sm_conn); 3740 } else { 3741 // initiator 3742 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3743 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3744 } else { 3745 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3746 } 3747 } 3748 break; 3749 3750 case SM_SC_W4_PAIRING_RANDOM: 3751 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3752 sm_pdu_received_in_wrong_state(sm_conn); 3753 break; 3754 } 3755 3756 // received random value 3757 reverse_128(&packet[1], setup->sm_peer_nonce); 3758 3759 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3760 // only check for JUST WORK/NC in initiator role AND passkey entry 3761 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3762 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3763 } 3764 3765 sm_sc_state_after_receiving_random(sm_conn); 3766 break; 3767 3768 case SM_SC_W2_CALCULATE_G2: 3769 case SM_SC_W4_CALCULATE_G2: 3770 case SM_SC_W4_CALCULATE_DHKEY: 3771 case SM_SC_W2_CALCULATE_F5_SALT: 3772 case SM_SC_W4_CALCULATE_F5_SALT: 3773 case SM_SC_W2_CALCULATE_F5_MACKEY: 3774 case SM_SC_W4_CALCULATE_F5_MACKEY: 3775 case SM_SC_W2_CALCULATE_F5_LTK: 3776 case SM_SC_W4_CALCULATE_F5_LTK: 3777 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3778 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3779 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3780 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3781 sm_pdu_received_in_wrong_state(sm_conn); 3782 break; 3783 } 3784 // store DHKey Check 3785 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3786 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3787 3788 // have we been only waiting for dhkey check command? 3789 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3790 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3791 } 3792 break; 3793 #endif 3794 3795 #ifdef ENABLE_LE_PERIPHERAL 3796 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3797 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3798 sm_pdu_received_in_wrong_state(sm_conn); 3799 break; 3800 } 3801 3802 // received confirm value 3803 reverse_128(&packet[1], setup->sm_peer_confirm); 3804 3805 // notify client to hide shown passkey 3806 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3807 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3808 } 3809 3810 // handle user cancel pairing? 3811 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3812 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3813 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3814 break; 3815 } 3816 3817 // wait for user action? 3818 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3819 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3820 break; 3821 } 3822 3823 // calculate and send local_confirm 3824 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3825 break; 3826 3827 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3828 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3829 sm_pdu_received_in_wrong_state(sm_conn); 3830 break;; 3831 } 3832 3833 // received random value 3834 reverse_128(&packet[1], setup->sm_peer_random); 3835 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3836 break; 3837 #endif 3838 3839 case SM_PH3_RECEIVE_KEYS: 3840 switch(sm_pdu_code){ 3841 case SM_CODE_ENCRYPTION_INFORMATION: 3842 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3843 reverse_128(&packet[1], setup->sm_peer_ltk); 3844 break; 3845 3846 case SM_CODE_MASTER_IDENTIFICATION: 3847 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3848 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3849 reverse_64(&packet[3], setup->sm_peer_rand); 3850 break; 3851 3852 case SM_CODE_IDENTITY_INFORMATION: 3853 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3854 reverse_128(&packet[1], setup->sm_peer_irk); 3855 break; 3856 3857 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3858 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3859 setup->sm_peer_addr_type = packet[1]; 3860 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3861 break; 3862 3863 case SM_CODE_SIGNING_INFORMATION: 3864 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3865 reverse_128(&packet[1], setup->sm_peer_csrk); 3866 break; 3867 default: 3868 // Unexpected PDU 3869 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3870 break; 3871 } 3872 // done with key distribution? 3873 if (sm_key_distribution_all_received(sm_conn)){ 3874 3875 sm_key_distribution_handle_all_received(sm_conn); 3876 3877 if (IS_RESPONDER(sm_conn->sm_role)){ 3878 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3879 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3880 } else { 3881 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3882 sm_done_for_handle(sm_conn->sm_handle); 3883 } 3884 } else { 3885 if (setup->sm_use_secure_connections){ 3886 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3887 } else { 3888 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3889 } 3890 } 3891 } 3892 break; 3893 default: 3894 // Unexpected PDU 3895 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3896 break; 3897 } 3898 3899 // try to send preparared packet 3900 sm_run(); 3901 } 3902 3903 // Security Manager Client API 3904 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3905 sm_get_oob_data = get_oob_data_callback; 3906 } 3907 3908 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3909 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3910 } 3911 3912 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3913 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3914 } 3915 3916 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3917 sm_min_encryption_key_size = min_size; 3918 sm_max_encryption_key_size = max_size; 3919 } 3920 3921 void sm_set_authentication_requirements(uint8_t auth_req){ 3922 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3923 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3924 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3925 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3926 } 3927 #endif 3928 sm_auth_req = auth_req; 3929 } 3930 3931 void sm_set_io_capabilities(io_capability_t io_capability){ 3932 sm_io_capabilities = io_capability; 3933 } 3934 3935 #ifdef ENABLE_LE_PERIPHERAL 3936 void sm_set_request_security(int enable){ 3937 sm_slave_request_security = enable; 3938 } 3939 #endif 3940 3941 void sm_set_er(sm_key_t er){ 3942 memcpy(sm_persistent_er, er, 16); 3943 } 3944 3945 void sm_set_ir(sm_key_t ir){ 3946 memcpy(sm_persistent_ir, ir, 16); 3947 } 3948 3949 // Testing support only 3950 void sm_test_set_irk(sm_key_t irk){ 3951 memcpy(sm_persistent_irk, irk, 16); 3952 sm_persistent_irk_ready = 1; 3953 } 3954 3955 void sm_test_use_fixed_local_csrk(void){ 3956 test_use_fixed_local_csrk = 1; 3957 } 3958 3959 void sm_init(void){ 3960 // set some (BTstack default) ER and IR 3961 int i; 3962 sm_key_t er; 3963 sm_key_t ir; 3964 for (i=0;i<16;i++){ 3965 er[i] = 0x30 + i; 3966 ir[i] = 0x90 + i; 3967 } 3968 sm_set_er(er); 3969 sm_set_ir(ir); 3970 // defaults 3971 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3972 | SM_STK_GENERATION_METHOD_OOB 3973 | SM_STK_GENERATION_METHOD_PASSKEY 3974 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3975 3976 sm_max_encryption_key_size = 16; 3977 sm_min_encryption_key_size = 7; 3978 3979 sm_fixed_passkey_in_display_role = 0xffffffff; 3980 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3981 3982 #ifdef ENABLE_CMAC_ENGINE 3983 sm_cmac_state = CMAC_IDLE; 3984 #endif 3985 dkg_state = DKG_W4_WORKING; 3986 rau_state = RAU_W4_WORKING; 3987 sm_aes128_state = SM_AES128_IDLE; 3988 sm_address_resolution_test = -1; // no private address to resolve yet 3989 sm_address_resolution_ah_calculation_active = 0; 3990 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3991 sm_address_resolution_general_queue = NULL; 3992 3993 gap_random_adress_update_period = 15 * 60 * 1000L; 3994 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3995 3996 test_use_fixed_local_csrk = 0; 3997 3998 // register for HCI Events from HCI 3999 hci_event_callback_registration.callback = &sm_event_packet_handler; 4000 hci_add_event_handler(&hci_event_callback_registration); 4001 4002 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4003 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4004 4005 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4006 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4007 #endif 4008 4009 #ifdef USE_MBEDTLS_FOR_ECDH 4010 mbedtls_ecp_group_init(&mbedtls_ec_group); 4011 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 4012 #endif 4013 } 4014 4015 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 4016 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4017 memcpy(&ec_q[0], qx, 32); 4018 memcpy(&ec_q[32], qy, 32); 4019 memcpy(ec_d, d, 32); 4020 sm_have_ec_keypair = 1; 4021 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4022 #else 4023 UNUSED(qx); 4024 UNUSED(qy); 4025 UNUSED(d); 4026 #endif 4027 } 4028 4029 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4030 static void parse_hex(uint8_t * buffer, const char * hex_string){ 4031 while (*hex_string){ 4032 int high_nibble = nibble_for_char(*hex_string++); 4033 int low_nibble = nibble_for_char(*hex_string++); 4034 *buffer++ = (high_nibble << 4) | low_nibble; 4035 } 4036 } 4037 #endif 4038 4039 void sm_test_use_fixed_ec_keypair(void){ 4040 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4041 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 4042 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 4043 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 4044 parse_hex(ec_d, ec_d_string); 4045 parse_hex(&ec_q[0], ec_qx_string); 4046 parse_hex(&ec_q[32], ec_qy_string); 4047 sm_have_ec_keypair = 1; 4048 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4049 #endif 4050 } 4051 4052 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4053 sm_fixed_passkey_in_display_role = passkey; 4054 } 4055 4056 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4057 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4058 } 4059 4060 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4061 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4062 if (!hci_con) return NULL; 4063 return &hci_con->sm_connection; 4064 } 4065 4066 // @returns 0 if not encrypted, 7-16 otherwise 4067 int sm_encryption_key_size(hci_con_handle_t con_handle){ 4068 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4069 if (!sm_conn) return 0; // wrong connection 4070 if (!sm_conn->sm_connection_encrypted) return 0; 4071 return sm_conn->sm_actual_encryption_key_size; 4072 } 4073 4074 int sm_authenticated(hci_con_handle_t con_handle){ 4075 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4076 if (!sm_conn) return 0; // wrong connection 4077 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 4078 return sm_conn->sm_connection_authenticated; 4079 } 4080 4081 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 4082 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4083 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 4084 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 4085 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 4086 return sm_conn->sm_connection_authorization_state; 4087 } 4088 4089 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4090 switch (sm_conn->sm_engine_state){ 4091 case SM_GENERAL_IDLE: 4092 case SM_RESPONDER_IDLE: 4093 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4094 sm_run(); 4095 break; 4096 default: 4097 break; 4098 } 4099 } 4100 4101 /** 4102 * @brief Trigger Security Request 4103 */ 4104 void sm_send_security_request(hci_con_handle_t con_handle){ 4105 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4106 if (!sm_conn) return; 4107 sm_send_security_request_for_connection(sm_conn); 4108 } 4109 4110 // request pairing 4111 void sm_request_pairing(hci_con_handle_t con_handle){ 4112 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4113 if (!sm_conn) return; // wrong connection 4114 4115 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4116 if (IS_RESPONDER(sm_conn->sm_role)){ 4117 sm_send_security_request_for_connection(sm_conn); 4118 } else { 4119 // used as a trigger to start central/master/initiator security procedures 4120 uint16_t ediv; 4121 sm_key_t ltk; 4122 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4123 switch (sm_conn->sm_irk_lookup_state){ 4124 case IRK_LOOKUP_FAILED: 4125 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4126 break; 4127 case IRK_LOOKUP_SUCCEEDED: 4128 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 4129 if (!sm_is_null_key(ltk) || ediv){ 4130 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 4131 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4132 } else { 4133 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4134 } 4135 break; 4136 default: 4137 sm_conn->sm_bonding_requested = 1; 4138 break; 4139 } 4140 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4141 sm_conn->sm_bonding_requested = 1; 4142 } 4143 } 4144 sm_run(); 4145 } 4146 4147 // called by client app on authorization request 4148 void sm_authorization_decline(hci_con_handle_t con_handle){ 4149 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4150 if (!sm_conn) return; // wrong connection 4151 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4152 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4153 } 4154 4155 void sm_authorization_grant(hci_con_handle_t con_handle){ 4156 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4157 if (!sm_conn) return; // wrong connection 4158 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4159 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4160 } 4161 4162 // GAP Bonding API 4163 4164 void sm_bonding_decline(hci_con_handle_t con_handle){ 4165 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4166 if (!sm_conn) return; // wrong connection 4167 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4168 4169 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4170 switch (setup->sm_stk_generation_method){ 4171 case PK_RESP_INPUT: 4172 case PK_INIT_INPUT: 4173 case OK_BOTH_INPUT: 4174 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 4175 break; 4176 case NK_BOTH_INPUT: 4177 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4178 break; 4179 case JUST_WORKS: 4180 case OOB: 4181 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4182 break; 4183 } 4184 } 4185 sm_run(); 4186 } 4187 4188 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4189 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4190 if (!sm_conn) return; // wrong connection 4191 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4192 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4193 if (setup->sm_use_secure_connections){ 4194 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4195 } else { 4196 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4197 } 4198 } 4199 4200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4201 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4202 sm_sc_prepare_dhkey_check(sm_conn); 4203 } 4204 #endif 4205 4206 sm_run(); 4207 } 4208 4209 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4210 // for now, it's the same 4211 sm_just_works_confirm(con_handle); 4212 } 4213 4214 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4215 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4216 if (!sm_conn) return; // wrong connection 4217 sm_reset_tk(); 4218 big_endian_store_32(setup->sm_tk, 12, passkey); 4219 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4220 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4221 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4222 } 4223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4224 memcpy(setup->sm_ra, setup->sm_tk, 16); 4225 memcpy(setup->sm_rb, setup->sm_tk, 16); 4226 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4227 sm_sc_start_calculating_local_confirm(sm_conn); 4228 } 4229 #endif 4230 sm_run(); 4231 } 4232 4233 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4234 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4235 if (!sm_conn) return; // wrong connection 4236 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4237 setup->sm_keypress_notification = action; 4238 sm_run(); 4239 } 4240 4241 /** 4242 * @brief Identify device in LE Device DB 4243 * @param handle 4244 * @returns index from le_device_db or -1 if not found/identified 4245 */ 4246 int sm_le_device_index(hci_con_handle_t con_handle ){ 4247 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4248 if (!sm_conn) return -1; 4249 return sm_conn->sm_le_db_index; 4250 } 4251 4252 static int gap_random_address_type_requires_updates(void){ 4253 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4254 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4255 return 1; 4256 } 4257 4258 static uint8_t own_address_type(void){ 4259 switch (gap_random_adress_type){ 4260 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4261 return BD_ADDR_TYPE_LE_PUBLIC; 4262 default: 4263 return BD_ADDR_TYPE_LE_RANDOM; 4264 } 4265 } 4266 4267 // GAP LE API 4268 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4269 gap_random_address_update_stop(); 4270 gap_random_adress_type = random_address_type; 4271 hci_le_set_own_address_type(own_address_type()); 4272 if (!gap_random_address_type_requires_updates()) return; 4273 gap_random_address_update_start(); 4274 gap_random_address_trigger(); 4275 } 4276 4277 gap_random_address_type_t gap_random_address_get_mode(void){ 4278 return gap_random_adress_type; 4279 } 4280 4281 void gap_random_address_set_update_period(int period_ms){ 4282 gap_random_adress_update_period = period_ms; 4283 if (!gap_random_address_type_requires_updates()) return; 4284 gap_random_address_update_stop(); 4285 gap_random_address_update_start(); 4286 } 4287 4288 void gap_random_address_set(bd_addr_t addr){ 4289 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4290 memcpy(sm_random_address, addr, 6); 4291 if (rau_state == RAU_W4_WORKING) return; 4292 rau_state = RAU_SET_ADDRESS; 4293 sm_run(); 4294 } 4295 4296 #ifdef ENABLE_LE_PERIPHERAL 4297 /* 4298 * @brief Set Advertisement Paramters 4299 * @param adv_int_min 4300 * @param adv_int_max 4301 * @param adv_type 4302 * @param direct_address_type 4303 * @param direct_address 4304 * @param channel_map 4305 * @param filter_policy 4306 * 4307 * @note own_address_type is used from gap_random_address_set_mode 4308 */ 4309 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4310 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4311 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4312 direct_address_typ, direct_address, channel_map, filter_policy); 4313 } 4314 #endif 4315