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