1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <stdio.h> 41 #include <string.h> 42 #include <inttypes.h> 43 44 #include "ble/le_device_db.h" 45 #include "ble/core.h" 46 #include "ble/sm.h" 47 #include "bluetooth_company_id.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "gap.h" 53 #include "hci.h" 54 #include "hci_dump.h" 55 #include "l2cap.h" 56 57 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 58 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 59 #endif 60 61 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 62 #define IS_RESPONDER(role) (role) 63 #else 64 #ifdef ENABLE_LE_CENTRAL 65 // only central - never responder (avoid 'unused variable' warnings) 66 #define IS_RESPONDER(role) (0 && role) 67 #else 68 // only peripheral - always responder (avoid 'unused variable' warnings) 69 #define IS_RESPONDER(role) (1 || role) 70 #endif 71 #endif 72 73 #ifdef ENABLE_LE_SECURE_CONNECTIONS 74 // assert SM Public Key can be sent/received 75 #if HCI_ACL_PAYLOAD_SIZE < 69 76 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 77 #endif 78 79 // configure ECC implementations 80 #ifdef ENABLE_LE_SECURE_CONNECTIONS 81 #if defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS) && defined(HAVE_MBEDTLS_ECC_P256) 82 #error "If you already have mbedTLS (HAVE_MBEDTLS_ECC_P256), please disable uECC (USE_MICRO_ECC_FOR_ECDH) in bstack_config.h" 83 #endif 84 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS 85 #define USE_SOFTWARE_ECDH_IMPLEMENTATION 86 #define USE_MICRO_ECC_FOR_ECDH 87 #endif 88 #ifdef HAVE_MBEDTLS_ECC_P256 89 #define USE_SOFTWARE_ECDH_IMPLEMENTATION 90 #define USE_MBEDTLS_FOR_ECDH 91 #endif 92 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 93 94 // Software ECDH implementation provided by micro-ecc 95 #ifdef USE_MICRO_ECC_FOR_ECDH 96 #include "uECC.h" 97 #endif 98 #endif 99 100 // Software ECDH implementation provided by mbedTLS 101 #ifdef USE_MBEDTLS_FOR_ECDH 102 #include "mbedtls/config.h" 103 #include "mbedtls/platform.h" 104 #include "mbedtls/ecp.h" 105 #endif 106 107 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 108 #define ENABLE_CMAC_ENGINE 109 #endif 110 111 // 112 // SM internal types and globals 113 // 114 115 typedef enum { 116 DKG_W4_WORKING, 117 DKG_CALC_IRK, 118 DKG_W4_IRK, 119 DKG_CALC_DHK, 120 DKG_W4_DHK, 121 DKG_READY 122 } derived_key_generation_t; 123 124 typedef enum { 125 RAU_W4_WORKING, 126 RAU_IDLE, 127 RAU_GET_RANDOM, 128 RAU_W4_RANDOM, 129 RAU_GET_ENC, 130 RAU_W4_ENC, 131 RAU_SET_ADDRESS, 132 } random_address_update_t; 133 134 typedef enum { 135 CMAC_IDLE, 136 CMAC_CALC_SUBKEYS, 137 CMAC_W4_SUBKEYS, 138 CMAC_CALC_MI, 139 CMAC_W4_MI, 140 CMAC_CALC_MLAST, 141 CMAC_W4_MLAST 142 } cmac_state_t; 143 144 typedef enum { 145 JUST_WORKS, 146 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 147 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 148 OK_BOTH_INPUT, // Only input on both, both input PK 149 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 150 OOB // OOB available on both sides 151 } stk_generation_method_t; 152 153 typedef enum { 154 SM_USER_RESPONSE_IDLE, 155 SM_USER_RESPONSE_PENDING, 156 SM_USER_RESPONSE_CONFIRM, 157 SM_USER_RESPONSE_PASSKEY, 158 SM_USER_RESPONSE_DECLINE 159 } sm_user_response_t; 160 161 typedef enum { 162 SM_AES128_IDLE, 163 SM_AES128_ACTIVE 164 } sm_aes128_state_t; 165 166 typedef enum { 167 ADDRESS_RESOLUTION_IDLE, 168 ADDRESS_RESOLUTION_GENERAL, 169 ADDRESS_RESOLUTION_FOR_CONNECTION, 170 } address_resolution_mode_t; 171 172 typedef enum { 173 ADDRESS_RESOLUTION_SUCEEDED, 174 ADDRESS_RESOLUTION_FAILED, 175 } address_resolution_event_t; 176 177 typedef enum { 178 EC_KEY_GENERATION_IDLE, 179 EC_KEY_GENERATION_ACTIVE, 180 EC_KEY_GENERATION_W4_KEY, 181 EC_KEY_GENERATION_DONE, 182 } ec_key_generation_state_t; 183 184 typedef enum { 185 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 186 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 187 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 188 } sm_state_var_t; 189 190 typedef enum { 191 SM_SC_OOB_IDLE, 192 SM_SC_OOB_W2_GET_RANDOM_1, 193 SM_SC_OOB_W4_RANDOM_1, 194 SM_SC_OOB_W2_GET_RANDOM_2, 195 SM_SC_OOB_W4_RANDOM_2, 196 SM_SC_OOB_W2_CALC_CONFIRM, 197 SM_SC_OOB_W4_CONFIRM, 198 } sm_sc_oob_state_t; 199 200 typedef uint8_t sm_key24_t[3]; 201 typedef uint8_t sm_key56_t[7]; 202 typedef uint8_t sm_key256_t[32]; 203 204 // 205 // GLOBAL DATA 206 // 207 208 static uint8_t test_use_fixed_local_csrk; 209 210 #ifdef ENABLE_TESTING_SUPPORT 211 static uint8_t test_pairing_failure; 212 #endif 213 214 // configuration 215 static uint8_t sm_accepted_stk_generation_methods; 216 static uint8_t sm_max_encryption_key_size; 217 static uint8_t sm_min_encryption_key_size; 218 static uint8_t sm_auth_req = 0; 219 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 220 static uint8_t sm_slave_request_security; 221 static uint32_t sm_fixed_passkey_in_display_role; 222 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 224 static uint8_t sm_have_ec_keypair; 225 #endif 226 227 #ifdef ENABLE_LE_SECURE_CONNECTIONS 228 static uint8_t sm_sc_oob_random[16]; 229 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 230 static sm_sc_oob_state_t sm_sc_oob_state; 231 #endif 232 233 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 234 static sm_key_t sm_persistent_er; 235 static sm_key_t sm_persistent_ir; 236 237 // derived from sm_persistent_ir 238 static sm_key_t sm_persistent_dhk; 239 static sm_key_t sm_persistent_irk; 240 static uint8_t sm_persistent_irk_ready = 0; // used for testing 241 static derived_key_generation_t dkg_state; 242 243 // derived from sm_persistent_er 244 // .. 245 246 // random address update 247 static random_address_update_t rau_state; 248 static bd_addr_t sm_random_address; 249 250 // CMAC Calculation: General 251 #ifdef ENABLE_CMAC_ENGINE 252 static cmac_state_t sm_cmac_state; 253 static uint16_t sm_cmac_message_len; 254 static sm_key_t sm_cmac_k; 255 static sm_key_t sm_cmac_x; 256 static sm_key_t sm_cmac_m_last; 257 static uint8_t sm_cmac_block_current; 258 static uint8_t sm_cmac_block_count; 259 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 260 static void (*sm_cmac_done_handler)(uint8_t * hash); 261 #endif 262 263 // CMAC for ATT Signed Writes 264 #ifdef ENABLE_LE_SIGNED_WRITE 265 static uint8_t sm_cmac_header[3]; 266 static const uint8_t * sm_cmac_message; 267 static uint8_t sm_cmac_sign_counter[4]; 268 #endif 269 270 // CMAC for Secure Connection functions 271 #ifdef ENABLE_LE_SECURE_CONNECTIONS 272 static sm_connection_t * sm_cmac_connection; 273 static uint8_t sm_cmac_sc_buffer[80]; 274 #endif 275 276 // resolvable private address lookup / CSRK calculation 277 static int sm_address_resolution_test; 278 static int sm_address_resolution_ah_calculation_active; 279 static uint8_t sm_address_resolution_addr_type; 280 static bd_addr_t sm_address_resolution_address; 281 static void * sm_address_resolution_context; 282 static address_resolution_mode_t sm_address_resolution_mode; 283 static btstack_linked_list_t sm_address_resolution_general_queue; 284 285 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 286 static sm_aes128_state_t sm_aes128_state; 287 static void * sm_aes128_context; 288 289 // use aes128 provided by MCU - not needed usually 290 #ifdef HAVE_AES128 291 static uint8_t aes128_result_flipped[16]; 292 static btstack_timer_source_t aes128_timer; 293 void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result); 294 #endif 295 296 // random engine. store context (ususally sm_connection_t) 297 static void * sm_random_context; 298 299 // to receive hci events 300 static btstack_packet_callback_registration_t hci_event_callback_registration; 301 302 /* to dispatch sm event */ 303 static btstack_linked_list_t sm_event_handlers; 304 305 // LE Secure Connections 306 #ifdef ENABLE_LE_SECURE_CONNECTIONS 307 static ec_key_generation_state_t ec_key_generation_state; 308 static uint8_t ec_d[32]; 309 static uint8_t ec_q[64]; 310 #endif 311 312 // Software ECDH implementation provided by mbedtls 313 #ifdef USE_MBEDTLS_FOR_ECDH 314 static mbedtls_ecp_group mbedtls_ec_group; 315 #endif 316 317 // 318 // Volume 3, Part H, Chapter 24 319 // "Security shall be initiated by the Security Manager in the device in the master role. 320 // The device in the slave role shall be the responding device." 321 // -> master := initiator, slave := responder 322 // 323 324 // data needed for security setup 325 typedef struct sm_setup_context { 326 327 btstack_timer_source_t sm_timeout; 328 329 // used in all phases 330 uint8_t sm_pairing_failed_reason; 331 332 // user response, (Phase 1 and/or 2) 333 uint8_t sm_user_response; 334 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 335 336 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 337 int sm_key_distribution_send_set; 338 int sm_key_distribution_received_set; 339 340 // Phase 2 (Pairing over SMP) 341 stk_generation_method_t sm_stk_generation_method; 342 sm_key_t sm_tk; 343 uint8_t sm_use_secure_connections; 344 345 sm_key_t sm_c1_t3_value; // c1 calculation 346 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 347 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 348 sm_key_t sm_local_random; 349 sm_key_t sm_local_confirm; 350 sm_key_t sm_peer_random; 351 sm_key_t sm_peer_confirm; 352 uint8_t sm_m_addr_type; // address and type can be removed 353 uint8_t sm_s_addr_type; // '' 354 bd_addr_t sm_m_address; // '' 355 bd_addr_t sm_s_address; // '' 356 sm_key_t sm_ltk; 357 358 uint8_t sm_state_vars; 359 #ifdef ENABLE_LE_SECURE_CONNECTIONS 360 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 361 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 362 sm_key_t sm_local_nonce; // might be combined with sm_local_random 363 sm_key_t sm_dhkey; 364 sm_key_t sm_peer_dhkey_check; 365 sm_key_t sm_local_dhkey_check; 366 sm_key_t sm_ra; 367 sm_key_t sm_rb; 368 sm_key_t sm_t; // used for f5 and h6 369 sm_key_t sm_mackey; 370 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 371 #endif 372 373 // Phase 3 374 375 // key distribution, we generate 376 uint16_t sm_local_y; 377 uint16_t sm_local_div; 378 uint16_t sm_local_ediv; 379 uint8_t sm_local_rand[8]; 380 sm_key_t sm_local_ltk; 381 sm_key_t sm_local_csrk; 382 sm_key_t sm_local_irk; 383 // sm_local_address/addr_type not needed 384 385 // key distribution, received from peer 386 uint16_t sm_peer_y; 387 uint16_t sm_peer_div; 388 uint16_t sm_peer_ediv; 389 uint8_t sm_peer_rand[8]; 390 sm_key_t sm_peer_ltk; 391 sm_key_t sm_peer_irk; 392 sm_key_t sm_peer_csrk; 393 uint8_t sm_peer_addr_type; 394 bd_addr_t sm_peer_address; 395 396 } sm_setup_context_t; 397 398 // 399 static sm_setup_context_t the_setup; 400 static sm_setup_context_t * setup = &the_setup; 401 402 // active connection - the one for which the_setup is used for 403 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 404 405 // @returns 1 if oob data is available 406 // stores oob data in provided 16 byte buffer if not null 407 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 408 409 // horizontal: initiator capabilities 410 // vertial: responder capabilities 411 static const stk_generation_method_t stk_generation_method [5] [5] = { 412 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 413 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 414 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 415 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 416 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 417 }; 418 419 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 420 #ifdef ENABLE_LE_SECURE_CONNECTIONS 421 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 422 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 423 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 424 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 425 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 426 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 427 }; 428 #endif 429 430 static void sm_run(void); 431 static void sm_done_for_handle(hci_con_handle_t con_handle); 432 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 433 static inline int sm_calc_actual_encryption_key_size(int other); 434 static int sm_validate_stk_generation_method(void); 435 static void sm_handle_encryption_result(uint8_t * data); 436 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 437 438 static void log_info_hex16(const char * name, uint16_t value){ 439 log_info("%-6s 0x%04x", name, value); 440 } 441 442 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 443 // return packet[0]; 444 // } 445 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 446 return packet[1]; 447 } 448 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 449 return packet[2]; 450 } 451 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 452 return packet[3]; 453 } 454 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 455 return packet[4]; 456 } 457 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 458 return packet[5]; 459 } 460 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 461 return packet[6]; 462 } 463 464 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 465 packet[0] = code; 466 } 467 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 468 packet[1] = io_capability; 469 } 470 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 471 packet[2] = oob_data_flag; 472 } 473 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 474 packet[3] = auth_req; 475 } 476 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 477 packet[4] = max_encryption_key_size; 478 } 479 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 480 packet[5] = initiator_key_distribution; 481 } 482 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 483 packet[6] = responder_key_distribution; 484 } 485 486 // @returns 1 if all bytes are 0 487 static int sm_is_null(uint8_t * data, int size){ 488 int i; 489 for (i=0; i < size ; i++){ 490 if (data[i]) return 0; 491 } 492 return 1; 493 } 494 495 static int sm_is_null_random(uint8_t random[8]){ 496 return sm_is_null(random, 8); 497 } 498 499 static int sm_is_null_key(uint8_t * key){ 500 return sm_is_null(key, 16); 501 } 502 503 // Key utils 504 static void sm_reset_tk(void){ 505 int i; 506 for (i=0;i<16;i++){ 507 setup->sm_tk[i] = 0; 508 } 509 } 510 511 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 512 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 513 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 514 int i; 515 for (i = max_encryption_size ; i < 16 ; i++){ 516 key[15-i] = 0; 517 } 518 } 519 520 // SMP Timeout implementation 521 522 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 523 // the Security Manager Timer shall be reset and started. 524 // 525 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 526 // 527 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 528 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 529 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 530 // established. 531 532 static void sm_timeout_handler(btstack_timer_source_t * timer){ 533 log_info("SM timeout"); 534 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 535 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 536 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 537 sm_done_for_handle(sm_conn->sm_handle); 538 539 // trigger handling of next ready connection 540 sm_run(); 541 } 542 static void sm_timeout_start(sm_connection_t * sm_conn){ 543 btstack_run_loop_remove_timer(&setup->sm_timeout); 544 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 545 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 546 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 547 btstack_run_loop_add_timer(&setup->sm_timeout); 548 } 549 static void sm_timeout_stop(void){ 550 btstack_run_loop_remove_timer(&setup->sm_timeout); 551 } 552 static void sm_timeout_reset(sm_connection_t * sm_conn){ 553 sm_timeout_stop(); 554 sm_timeout_start(sm_conn); 555 } 556 557 // end of sm timeout 558 559 // GAP Random Address updates 560 static gap_random_address_type_t gap_random_adress_type; 561 static btstack_timer_source_t gap_random_address_update_timer; 562 static uint32_t gap_random_adress_update_period; 563 564 static void gap_random_address_trigger(void){ 565 if (rau_state != RAU_IDLE) return; 566 log_info("gap_random_address_trigger"); 567 rau_state = RAU_GET_RANDOM; 568 sm_run(); 569 } 570 571 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 572 UNUSED(timer); 573 574 log_info("GAP Random Address Update due"); 575 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 576 btstack_run_loop_add_timer(&gap_random_address_update_timer); 577 gap_random_address_trigger(); 578 } 579 580 static void gap_random_address_update_start(void){ 581 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 582 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 583 btstack_run_loop_add_timer(&gap_random_address_update_timer); 584 } 585 586 static void gap_random_address_update_stop(void){ 587 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 588 } 589 590 591 static void sm_random_start(void * context){ 592 sm_random_context = context; 593 hci_send_cmd(&hci_le_rand); 594 } 595 596 #ifdef HAVE_AES128 597 static void aes128_completed(btstack_timer_source_t * ts){ 598 UNUSED(ts); 599 sm_handle_encryption_result(&aes128_result_flipped[0]); 600 sm_run(); 601 } 602 #endif 603 604 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 605 // context is made availabe to aes128 result handler by this 606 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 607 sm_aes128_state = SM_AES128_ACTIVE; 608 sm_aes128_context = context; 609 610 #ifdef HAVE_AES128 611 // calc result directly 612 sm_key_t result; 613 btstack_aes128_calc(key, plaintext, result); 614 615 // log 616 log_info_key("key", key); 617 log_info_key("txt", plaintext); 618 log_info_key("res", result); 619 620 // flip 621 reverse_128(&result[0], &aes128_result_flipped[0]); 622 623 // deliver via timer 624 btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed); 625 btstack_run_loop_set_timer(&aes128_timer, 0); // no delay 626 btstack_run_loop_add_timer(&aes128_timer); 627 #else 628 sm_key_t key_flipped, plaintext_flipped; 629 reverse_128(key, key_flipped); 630 reverse_128(plaintext, plaintext_flipped); 631 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 632 #endif 633 } 634 635 // ah(k,r) helper 636 // r = padding || r 637 // r - 24 bit value 638 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 639 // r'= padding || r 640 memset(r_prime, 0, 16); 641 memcpy(&r_prime[13], r, 3); 642 } 643 644 // d1 helper 645 // d' = padding || r || d 646 // d,r - 16 bit values 647 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 648 // d'= padding || r || d 649 memset(d1_prime, 0, 16); 650 big_endian_store_16(d1_prime, 12, r); 651 big_endian_store_16(d1_prime, 14, d); 652 } 653 654 // dm helper 655 // r’ = padding || r 656 // r - 64 bit value 657 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 658 memset(r_prime, 0, 16); 659 memcpy(&r_prime[8], r, 8); 660 } 661 662 // calculate arguments for first AES128 operation in C1 function 663 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){ 664 665 // p1 = pres || preq || rat’ || iat’ 666 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 667 // cant octet of pres becomes the most significant octet of p1. 668 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 669 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 670 // p1 is 0x05000800000302070710000001010001." 671 672 sm_key_t p1; 673 reverse_56(pres, &p1[0]); 674 reverse_56(preq, &p1[7]); 675 p1[14] = rat; 676 p1[15] = iat; 677 log_info_key("p1", p1); 678 log_info_key("r", r); 679 680 // t1 = r xor p1 681 int i; 682 for (i=0;i<16;i++){ 683 t1[i] = r[i] ^ p1[i]; 684 } 685 log_info_key("t1", t1); 686 } 687 688 // calculate arguments for second AES128 operation in C1 function 689 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 690 // p2 = padding || ia || ra 691 // "The least significant octet of ra becomes the least significant octet of p2 and 692 // the most significant octet of padding becomes the most significant octet of p2. 693 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 694 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 695 696 sm_key_t p2; 697 memset(p2, 0, 16); 698 memcpy(&p2[4], ia, 6); 699 memcpy(&p2[10], ra, 6); 700 log_info_key("p2", p2); 701 702 // c1 = e(k, t2_xor_p2) 703 int i; 704 for (i=0;i<16;i++){ 705 t3[i] = t2[i] ^ p2[i]; 706 } 707 log_info_key("t3", t3); 708 } 709 710 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 711 log_info_key("r1", r1); 712 log_info_key("r2", r2); 713 memcpy(&r_prime[8], &r2[8], 8); 714 memcpy(&r_prime[0], &r1[8], 8); 715 } 716 717 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 718 UNUSED(channel); 719 720 // log event 721 hci_dump_packet(packet_type, 1, packet, size); 722 // dispatch to all event handlers 723 btstack_linked_list_iterator_t it; 724 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 725 while (btstack_linked_list_iterator_has_next(&it)){ 726 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 727 entry->callback(packet_type, 0, packet, size); 728 } 729 } 730 731 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){ 732 event[0] = type; 733 event[1] = event_size - 2; 734 little_endian_store_16(event, 2, con_handle); 735 event[4] = addr_type; 736 reverse_bd_addr(address, &event[5]); 737 } 738 739 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 740 uint8_t event[11]; 741 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 742 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 743 } 744 745 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){ 746 uint8_t event[15]; 747 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 748 little_endian_store_32(event, 11, passkey); 749 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 750 } 751 752 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){ 753 // fetch addr and addr type from db 754 bd_addr_t identity_address; 755 int identity_address_type; 756 le_device_db_info(index, &identity_address_type, identity_address, NULL); 757 758 uint8_t event[19]; 759 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 760 event[11] = identity_address_type; 761 reverse_bd_addr(identity_address, &event[12]); 762 event[18] = index; 763 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 764 } 765 766 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 767 uint8_t event[12]; 768 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 769 event[11] = status; 770 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 771 } 772 773 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 774 uint8_t event[13]; 775 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 776 event[11] = status; 777 event[12] = reason; 778 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 779 } 780 781 // decide on stk generation based on 782 // - pairing request 783 // - io capabilities 784 // - OOB data availability 785 static void sm_setup_tk(void){ 786 787 // default: just works 788 setup->sm_stk_generation_method = JUST_WORKS; 789 790 #ifdef ENABLE_LE_SECURE_CONNECTIONS 791 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 792 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 793 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 794 memset(setup->sm_ra, 0, 16); 795 memset(setup->sm_rb, 0, 16); 796 #else 797 setup->sm_use_secure_connections = 0; 798 #endif 799 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 800 801 802 // decide if OOB will be used based on SC vs. Legacy and oob flags 803 int use_oob = 0; 804 if (setup->sm_use_secure_connections){ 805 // In LE Secure Connections pairing, the out of band method is used if at least 806 // one device has the peer device's out of band authentication data available. 807 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 808 } else { 809 // In LE legacy pairing, the out of band method is used if both the devices have 810 // the other device's out of band authentication data available. 811 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 812 } 813 if (use_oob){ 814 log_info("SM: have OOB data"); 815 log_info_key("OOB", setup->sm_tk); 816 setup->sm_stk_generation_method = OOB; 817 return; 818 } 819 820 // If both devices have not set the MITM option in the Authentication Requirements 821 // Flags, then the IO capabilities shall be ignored and the Just Works association 822 // model shall be used. 823 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 824 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 825 log_info("SM: MITM not required by both -> JUST WORKS"); 826 return; 827 } 828 829 // Reset TK as it has been setup in sm_init_setup 830 sm_reset_tk(); 831 832 // Also use just works if unknown io capabilites 833 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)){ 834 return; 835 } 836 837 // Otherwise the IO capabilities of the devices shall be used to determine the 838 // pairing method as defined in Table 2.4. 839 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 840 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 841 842 #ifdef ENABLE_LE_SECURE_CONNECTIONS 843 // table not define by default 844 if (setup->sm_use_secure_connections){ 845 generation_method = stk_generation_method_with_secure_connection; 846 } 847 #endif 848 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)]; 849 850 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 851 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); 852 } 853 854 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 855 int flags = 0; 856 if (key_set & SM_KEYDIST_ENC_KEY){ 857 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 858 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 859 } 860 if (key_set & SM_KEYDIST_ID_KEY){ 861 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 862 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 863 } 864 if (key_set & SM_KEYDIST_SIGN){ 865 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 866 } 867 return flags; 868 } 869 870 static void sm_setup_key_distribution(uint8_t key_set){ 871 setup->sm_key_distribution_received_set = 0; 872 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 873 } 874 875 // CSRK Key Lookup 876 877 878 static int sm_address_resolution_idle(void){ 879 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 880 } 881 882 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){ 883 memcpy(sm_address_resolution_address, addr, 6); 884 sm_address_resolution_addr_type = addr_type; 885 sm_address_resolution_test = 0; 886 sm_address_resolution_mode = mode; 887 sm_address_resolution_context = context; 888 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 889 } 890 891 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 892 // check if already in list 893 btstack_linked_list_iterator_t it; 894 sm_lookup_entry_t * entry; 895 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 896 while(btstack_linked_list_iterator_has_next(&it)){ 897 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 898 if (entry->address_type != address_type) continue; 899 if (memcmp(entry->address, address, 6)) continue; 900 // already in list 901 return BTSTACK_BUSY; 902 } 903 entry = btstack_memory_sm_lookup_entry_get(); 904 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 905 entry->address_type = (bd_addr_type_t) address_type; 906 memcpy(entry->address, address, 6); 907 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 908 sm_run(); 909 return 0; 910 } 911 912 // 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 913 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 914 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 915 } 916 static inline void dkg_next_state(void){ 917 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 918 } 919 static inline void rau_next_state(void){ 920 rau_state = (random_address_update_t) (((int)rau_state) + 1); 921 } 922 923 // CMAC calculation using AES Engine 924 #ifdef ENABLE_CMAC_ENGINE 925 926 static inline void sm_cmac_next_state(void){ 927 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 928 } 929 930 static int sm_cmac_last_block_complete(void){ 931 if (sm_cmac_message_len == 0) return 0; 932 return (sm_cmac_message_len & 0x0f) == 0; 933 } 934 935 int sm_cmac_ready(void){ 936 return sm_cmac_state == CMAC_IDLE; 937 } 938 939 // generic cmac calculation 940 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])){ 941 // Generalized CMAC 942 memcpy(sm_cmac_k, key, 16); 943 memset(sm_cmac_x, 0, 16); 944 sm_cmac_block_current = 0; 945 sm_cmac_message_len = message_len; 946 sm_cmac_done_handler = done_callback; 947 sm_cmac_get_byte = get_byte_callback; 948 949 // step 2: n := ceil(len/const_Bsize); 950 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 951 952 // step 3: .. 953 if (sm_cmac_block_count==0){ 954 sm_cmac_block_count = 1; 955 } 956 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 957 958 // first, we need to compute l for k1, k2, and m_last 959 sm_cmac_state = CMAC_CALC_SUBKEYS; 960 961 // let's go 962 sm_run(); 963 } 964 #endif 965 966 // cmac for ATT Message signing 967 #ifdef ENABLE_LE_SIGNED_WRITE 968 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 969 if (offset >= sm_cmac_message_len) { 970 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 971 return 0; 972 } 973 974 offset = sm_cmac_message_len - 1 - offset; 975 976 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 977 if (offset < 3){ 978 return sm_cmac_header[offset]; 979 } 980 int actual_message_len_incl_header = sm_cmac_message_len - 4; 981 if (offset < actual_message_len_incl_header){ 982 return sm_cmac_message[offset - 3]; 983 } 984 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 985 } 986 987 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)){ 988 // ATT Message Signing 989 sm_cmac_header[0] = opcode; 990 little_endian_store_16(sm_cmac_header, 1, con_handle); 991 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 992 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 993 sm_cmac_message = message; 994 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 995 } 996 #endif 997 998 #ifdef ENABLE_CMAC_ENGINE 999 static void sm_cmac_handle_aes_engine_ready(void){ 1000 switch (sm_cmac_state){ 1001 case CMAC_CALC_SUBKEYS: { 1002 sm_key_t const_zero; 1003 memset(const_zero, 0, 16); 1004 sm_cmac_next_state(); 1005 sm_aes128_start(sm_cmac_k, const_zero, NULL); 1006 break; 1007 } 1008 case CMAC_CALC_MI: { 1009 int j; 1010 sm_key_t y; 1011 for (j=0;j<16;j++){ 1012 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 1013 } 1014 sm_cmac_block_current++; 1015 sm_cmac_next_state(); 1016 sm_aes128_start(sm_cmac_k, y, NULL); 1017 break; 1018 } 1019 case CMAC_CALC_MLAST: { 1020 int i; 1021 sm_key_t y; 1022 for (i=0;i<16;i++){ 1023 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1024 } 1025 log_info_key("Y", y); 1026 sm_cmac_block_current++; 1027 sm_cmac_next_state(); 1028 sm_aes128_start(sm_cmac_k, y, NULL); 1029 break; 1030 } 1031 default: 1032 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1033 break; 1034 } 1035 } 1036 1037 // CMAC Implementation using AES128 engine 1038 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1039 int i; 1040 int carry = 0; 1041 for (i=len-1; i >= 0 ; i--){ 1042 int new_carry = data[i] >> 7; 1043 data[i] = data[i] << 1 | carry; 1044 carry = new_carry; 1045 } 1046 } 1047 1048 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1049 switch (sm_cmac_state){ 1050 case CMAC_W4_SUBKEYS: { 1051 sm_key_t k1; 1052 memcpy(k1, data, 16); 1053 sm_shift_left_by_one_bit_inplace(16, k1); 1054 if (data[0] & 0x80){ 1055 k1[15] ^= 0x87; 1056 } 1057 sm_key_t k2; 1058 memcpy(k2, k1, 16); 1059 sm_shift_left_by_one_bit_inplace(16, k2); 1060 if (k1[0] & 0x80){ 1061 k2[15] ^= 0x87; 1062 } 1063 1064 log_info_key("k", sm_cmac_k); 1065 log_info_key("k1", k1); 1066 log_info_key("k2", k2); 1067 1068 // step 4: set m_last 1069 int i; 1070 if (sm_cmac_last_block_complete()){ 1071 for (i=0;i<16;i++){ 1072 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1073 } 1074 } else { 1075 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1076 for (i=0;i<16;i++){ 1077 if (i < valid_octets_in_last_block){ 1078 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1079 continue; 1080 } 1081 if (i == valid_octets_in_last_block){ 1082 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1083 continue; 1084 } 1085 sm_cmac_m_last[i] = k2[i]; 1086 } 1087 } 1088 1089 // next 1090 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1091 break; 1092 } 1093 case CMAC_W4_MI: 1094 memcpy(sm_cmac_x, data, 16); 1095 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1096 break; 1097 case CMAC_W4_MLAST: 1098 // done 1099 log_info("Setting CMAC Engine to IDLE"); 1100 sm_cmac_state = CMAC_IDLE; 1101 log_info_key("CMAC", data); 1102 sm_cmac_done_handler(data); 1103 break; 1104 default: 1105 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1106 break; 1107 } 1108 } 1109 #endif 1110 1111 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1112 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1113 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1114 switch (setup->sm_stk_generation_method){ 1115 case PK_RESP_INPUT: 1116 if (IS_RESPONDER(sm_conn->sm_role)){ 1117 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1118 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1119 } else { 1120 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)); 1121 } 1122 break; 1123 case PK_INIT_INPUT: 1124 if (IS_RESPONDER(sm_conn->sm_role)){ 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 } else { 1127 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1128 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1129 } 1130 break; 1131 case OK_BOTH_INPUT: 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 break; 1135 case NK_BOTH_INPUT: 1136 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1137 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)); 1138 break; 1139 case JUST_WORKS: 1140 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1141 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1142 break; 1143 case OOB: 1144 // client already provided OOB data, let's skip notification. 1145 break; 1146 } 1147 } 1148 1149 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1150 int recv_flags; 1151 if (IS_RESPONDER(sm_conn->sm_role)){ 1152 // slave / responder 1153 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1154 } else { 1155 // master / initiator 1156 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1157 } 1158 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1159 return recv_flags == setup->sm_key_distribution_received_set; 1160 } 1161 1162 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1163 if (sm_active_connection_handle == con_handle){ 1164 sm_timeout_stop(); 1165 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1166 log_info("sm: connection 0x%x released setup context", con_handle); 1167 } 1168 } 1169 1170 static int sm_key_distribution_flags_for_auth_req(void){ 1171 1172 int flags = SM_KEYDIST_ID_KEY; 1173 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1174 // encryption and signing information only if bonding requested 1175 flags |= SM_KEYDIST_ENC_KEY; 1176 #ifdef ENABLE_LE_SIGNED_WRITE 1177 flags |= SM_KEYDIST_SIGN; 1178 #endif 1179 } 1180 return flags; 1181 } 1182 1183 static void sm_reset_setup(void){ 1184 // fill in sm setup 1185 setup->sm_state_vars = 0; 1186 setup->sm_keypress_notification = 0; 1187 sm_reset_tk(); 1188 } 1189 1190 static void sm_init_setup(sm_connection_t * sm_conn){ 1191 1192 // fill in sm setup 1193 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1194 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1195 1196 // query client for OOB data 1197 int have_oob_data = 0; 1198 if (sm_get_oob_data) { 1199 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1200 } 1201 1202 sm_pairing_packet_t * local_packet; 1203 if (IS_RESPONDER(sm_conn->sm_role)){ 1204 // slave 1205 local_packet = &setup->sm_s_pres; 1206 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1207 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1208 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1209 } else { 1210 // master 1211 local_packet = &setup->sm_m_preq; 1212 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1213 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1214 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1215 1216 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1217 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1218 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1219 } 1220 1221 uint8_t auth_req = sm_auth_req; 1222 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1223 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1224 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1225 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1226 } 1227 1228 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1229 1230 sm_pairing_packet_t * remote_packet; 1231 int remote_key_request; 1232 if (IS_RESPONDER(sm_conn->sm_role)){ 1233 // slave / responder 1234 remote_packet = &setup->sm_m_preq; 1235 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1236 } else { 1237 // master / initiator 1238 remote_packet = &setup->sm_s_pres; 1239 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1240 } 1241 1242 // check key size 1243 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1244 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1245 1246 // decide on STK generation method 1247 sm_setup_tk(); 1248 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1249 1250 // check if STK generation method is acceptable by client 1251 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1252 1253 // identical to responder 1254 sm_setup_key_distribution(remote_key_request); 1255 1256 // JUST WORKS doens't provide authentication 1257 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1258 1259 return 0; 1260 } 1261 1262 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1263 1264 // cache and reset context 1265 int matched_device_id = sm_address_resolution_test; 1266 address_resolution_mode_t mode = sm_address_resolution_mode; 1267 void * context = sm_address_resolution_context; 1268 1269 // reset context 1270 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1271 sm_address_resolution_context = NULL; 1272 sm_address_resolution_test = -1; 1273 hci_con_handle_t con_handle = 0; 1274 1275 sm_connection_t * sm_connection; 1276 #ifdef ENABLE_LE_CENTRAL 1277 sm_key_t ltk; 1278 #endif 1279 switch (mode){ 1280 case ADDRESS_RESOLUTION_GENERAL: 1281 break; 1282 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1283 sm_connection = (sm_connection_t *) context; 1284 con_handle = sm_connection->sm_handle; 1285 switch (event){ 1286 case ADDRESS_RESOLUTION_SUCEEDED: 1287 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1288 sm_connection->sm_le_db_index = matched_device_id; 1289 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1290 if (sm_connection->sm_role) { 1291 // LTK request received before, IRK required -> start LTK calculation 1292 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1293 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1294 } 1295 break; 1296 } 1297 #ifdef ENABLE_LE_CENTRAL 1298 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1299 sm_connection->sm_security_request_received = 0; 1300 sm_connection->sm_pairing_requested = 0; 1301 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1302 if (!sm_is_null_key(ltk)){ 1303 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1304 } else { 1305 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1306 } 1307 #endif 1308 break; 1309 case ADDRESS_RESOLUTION_FAILED: 1310 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1311 if (sm_connection->sm_role) { 1312 // LTK request received before, IRK required -> negative LTK reply 1313 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1314 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1315 } 1316 break; 1317 } 1318 #ifdef ENABLE_LE_CENTRAL 1319 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1320 sm_connection->sm_security_request_received = 0; 1321 sm_connection->sm_pairing_requested = 0; 1322 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1323 #endif 1324 break; 1325 } 1326 break; 1327 default: 1328 break; 1329 } 1330 1331 switch (event){ 1332 case ADDRESS_RESOLUTION_SUCEEDED: 1333 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1334 break; 1335 case ADDRESS_RESOLUTION_FAILED: 1336 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1337 break; 1338 } 1339 } 1340 1341 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1342 1343 int le_db_index = -1; 1344 1345 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1346 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1347 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1348 & SM_AUTHREQ_BONDING ) != 0; 1349 1350 if (bonding_enabed){ 1351 1352 // lookup device based on IRK 1353 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1354 int i; 1355 for (i=0; i < le_device_db_max_count(); i++){ 1356 sm_key_t irk; 1357 bd_addr_t address; 1358 int address_type; 1359 le_device_db_info(i, &address_type, address, irk); 1360 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1361 log_info("sm: device found for IRK, updating"); 1362 le_db_index = i; 1363 break; 1364 } 1365 } 1366 } 1367 1368 // if not found, lookup via public address if possible 1369 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1370 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1371 int i; 1372 for (i=0; i < le_device_db_max_count(); i++){ 1373 bd_addr_t address; 1374 int address_type; 1375 le_device_db_info(i, &address_type, address, NULL); 1376 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1377 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1378 log_info("sm: device found for public address, updating"); 1379 le_db_index = i; 1380 break; 1381 } 1382 } 1383 } 1384 1385 // if not found, add to db 1386 if (le_db_index < 0) { 1387 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1388 } 1389 1390 if (le_db_index >= 0){ 1391 1392 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1393 1394 #ifdef ENABLE_LE_SIGNED_WRITE 1395 // store local CSRK 1396 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1397 log_info("sm: store local CSRK"); 1398 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1399 le_device_db_local_counter_set(le_db_index, 0); 1400 } 1401 1402 // store remote CSRK 1403 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1404 log_info("sm: store remote CSRK"); 1405 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1406 le_device_db_remote_counter_set(le_db_index, 0); 1407 } 1408 #endif 1409 // store encryption information for secure connections: LTK generated by ECDH 1410 if (setup->sm_use_secure_connections){ 1411 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1412 uint8_t zero_rand[8]; 1413 memset(zero_rand, 0, 8); 1414 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1415 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1416 } 1417 1418 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1419 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1420 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1421 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1422 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1423 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1424 1425 } 1426 } 1427 } else { 1428 log_info("Ignoring received keys, bonding not enabled"); 1429 } 1430 1431 // keep le_db_index 1432 sm_conn->sm_le_db_index = le_db_index; 1433 } 1434 1435 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1436 setup->sm_pairing_failed_reason = reason; 1437 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1438 } 1439 1440 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1441 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1442 } 1443 1444 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1445 1446 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1447 static int sm_passkey_used(stk_generation_method_t method); 1448 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1449 1450 static void sm_log_ec_keypair(void){ 1451 log_info("Elliptic curve: X"); 1452 log_info_hexdump(&ec_q[0],32); 1453 log_info("Elliptic curve: Y"); 1454 log_info_hexdump(&ec_q[32],32); 1455 } 1456 1457 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1458 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1459 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1460 } else { 1461 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1462 } 1463 } 1464 1465 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1466 if (IS_RESPONDER(sm_conn->sm_role)){ 1467 // Responder 1468 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1469 } else { 1470 // Initiator role 1471 switch (setup->sm_stk_generation_method){ 1472 case JUST_WORKS: 1473 sm_sc_prepare_dhkey_check(sm_conn); 1474 break; 1475 1476 case NK_BOTH_INPUT: 1477 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1478 break; 1479 case PK_INIT_INPUT: 1480 case PK_RESP_INPUT: 1481 case OK_BOTH_INPUT: 1482 if (setup->sm_passkey_bit < 20) { 1483 sm_sc_start_calculating_local_confirm(sm_conn); 1484 } else { 1485 sm_sc_prepare_dhkey_check(sm_conn); 1486 } 1487 break; 1488 case OOB: 1489 sm_sc_prepare_dhkey_check(sm_conn); 1490 break; 1491 } 1492 } 1493 } 1494 1495 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1496 return sm_cmac_sc_buffer[offset]; 1497 } 1498 1499 static void sm_sc_cmac_done(uint8_t * hash){ 1500 log_info("sm_sc_cmac_done: "); 1501 log_info_hexdump(hash, 16); 1502 1503 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1504 sm_sc_oob_state = SM_SC_OOB_IDLE; 1505 (*sm_sc_oob_callback)(sm_sc_oob_random, hash); 1506 return; 1507 } 1508 1509 sm_connection_t * sm_conn = sm_cmac_connection; 1510 sm_cmac_connection = NULL; 1511 #ifdef ENABLE_CLASSIC 1512 link_key_type_t link_key_type; 1513 #endif 1514 1515 switch (sm_conn->sm_engine_state){ 1516 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1517 memcpy(setup->sm_local_confirm, hash, 16); 1518 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1519 break; 1520 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1521 // check 1522 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1523 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1524 break; 1525 } 1526 sm_sc_state_after_receiving_random(sm_conn); 1527 break; 1528 case SM_SC_W4_CALCULATE_G2: { 1529 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1530 big_endian_store_32(setup->sm_tk, 12, vab); 1531 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1532 sm_trigger_user_response(sm_conn); 1533 break; 1534 } 1535 case SM_SC_W4_CALCULATE_F5_SALT: 1536 memcpy(setup->sm_t, hash, 16); 1537 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1538 break; 1539 case SM_SC_W4_CALCULATE_F5_MACKEY: 1540 memcpy(setup->sm_mackey, hash, 16); 1541 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1542 break; 1543 case SM_SC_W4_CALCULATE_F5_LTK: 1544 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1545 // Errata Service Release to the Bluetooth Specification: ESR09 1546 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1547 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1548 memcpy(setup->sm_ltk, hash, 16); 1549 memcpy(setup->sm_local_ltk, hash, 16); 1550 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1551 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1552 break; 1553 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1554 memcpy(setup->sm_local_dhkey_check, hash, 16); 1555 if (IS_RESPONDER(sm_conn->sm_role)){ 1556 // responder 1557 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1558 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1559 } else { 1560 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1561 } 1562 } else { 1563 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1564 } 1565 break; 1566 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1567 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1568 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1569 break; 1570 } 1571 if (IS_RESPONDER(sm_conn->sm_role)){ 1572 // responder 1573 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1574 } else { 1575 // initiator 1576 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1577 } 1578 break; 1579 case SM_SC_W4_CALCULATE_H6_ILK: 1580 memcpy(setup->sm_t, hash, 16); 1581 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1582 break; 1583 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1584 #ifdef ENABLE_CLASSIC 1585 reverse_128(hash, setup->sm_t); 1586 link_key_type = sm_conn->sm_connection_authenticated ? 1587 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1588 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1589 if (IS_RESPONDER(sm_conn->sm_role)){ 1590 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1591 } else { 1592 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1593 } 1594 #endif 1595 if (IS_RESPONDER(sm_conn->sm_role)){ 1596 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1597 } else { 1598 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1599 } 1600 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1601 sm_done_for_handle(sm_conn->sm_handle); 1602 break; 1603 default: 1604 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1605 break; 1606 } 1607 sm_run(); 1608 } 1609 1610 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){ 1611 const uint16_t message_len = 65; 1612 sm_cmac_connection = sm_conn; 1613 memcpy(sm_cmac_sc_buffer, u, 32); 1614 memcpy(sm_cmac_sc_buffer+32, v, 32); 1615 sm_cmac_sc_buffer[64] = z; 1616 log_info("f4 key"); 1617 log_info_hexdump(x, 16); 1618 log_info("f4 message"); 1619 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1620 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1621 } 1622 1623 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1624 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1625 static const uint8_t f5_length[] = { 0x01, 0x00}; 1626 1627 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1628 1629 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1630 memset(dhkey, 0, 32); 1631 1632 #ifdef USE_MICRO_ECC_FOR_ECDH 1633 #if uECC_SUPPORTS_secp256r1 1634 // standard version 1635 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1()); 1636 #else 1637 // static version 1638 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1639 #endif 1640 #endif 1641 1642 #ifdef USE_MBEDTLS_FOR_ECDH 1643 // da * Pb 1644 mbedtls_mpi d; 1645 mbedtls_ecp_point Q; 1646 mbedtls_ecp_point DH; 1647 mbedtls_mpi_init(&d); 1648 mbedtls_ecp_point_init(&Q); 1649 mbedtls_ecp_point_init(&DH); 1650 mbedtls_mpi_read_binary(&d, ec_d, 32); 1651 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); 1652 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 1653 mbedtls_mpi_lset(&Q.Z, 1); 1654 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1655 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1656 mbedtls_ecp_point_free(&DH); 1657 mbedtls_mpi_free(&d); 1658 mbedtls_ecp_point_free(&Q); 1659 #endif 1660 1661 log_info("dhkey"); 1662 log_info_hexdump(dhkey, 32); 1663 } 1664 #endif 1665 1666 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1667 // calculate salt for f5 1668 const uint16_t message_len = 32; 1669 sm_cmac_connection = sm_conn; 1670 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1671 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1672 } 1673 1674 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){ 1675 const uint16_t message_len = 53; 1676 sm_cmac_connection = sm_conn; 1677 1678 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1679 sm_cmac_sc_buffer[0] = 0; 1680 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1681 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1682 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1683 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1684 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1685 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1686 log_info("f5 key"); 1687 log_info_hexdump(t, 16); 1688 log_info("f5 message for MacKey"); 1689 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1690 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1691 } 1692 1693 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1694 sm_key56_t bd_addr_master, bd_addr_slave; 1695 bd_addr_master[0] = setup->sm_m_addr_type; 1696 bd_addr_slave[0] = setup->sm_s_addr_type; 1697 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1698 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1699 if (IS_RESPONDER(sm_conn->sm_role)){ 1700 // responder 1701 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1702 } else { 1703 // initiator 1704 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1705 } 1706 } 1707 1708 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1709 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1710 const uint16_t message_len = 53; 1711 sm_cmac_connection = sm_conn; 1712 sm_cmac_sc_buffer[0] = 1; 1713 // 1..52 setup before 1714 log_info("f5 key"); 1715 log_info_hexdump(t, 16); 1716 log_info("f5 message for LTK"); 1717 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1718 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1719 } 1720 1721 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1722 f5_ltk(sm_conn, setup->sm_t); 1723 } 1724 1725 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){ 1726 const uint16_t message_len = 65; 1727 sm_cmac_connection = sm_conn; 1728 memcpy(sm_cmac_sc_buffer, n1, 16); 1729 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1730 memcpy(sm_cmac_sc_buffer+32, r, 16); 1731 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1732 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1733 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1734 log_info("f6 key"); 1735 log_info_hexdump(w, 16); 1736 log_info("f6 message"); 1737 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1738 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1739 } 1740 1741 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1742 // - U is 256 bits 1743 // - V is 256 bits 1744 // - X is 128 bits 1745 // - Y is 128 bits 1746 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){ 1747 const uint16_t message_len = 80; 1748 sm_cmac_connection = sm_conn; 1749 memcpy(sm_cmac_sc_buffer, u, 32); 1750 memcpy(sm_cmac_sc_buffer+32, v, 32); 1751 memcpy(sm_cmac_sc_buffer+64, y, 16); 1752 log_info("g2 key"); 1753 log_info_hexdump(x, 16); 1754 log_info("g2 message"); 1755 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1756 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1757 } 1758 1759 static void g2_calculate(sm_connection_t * sm_conn) { 1760 // calc Va if numeric comparison 1761 if (IS_RESPONDER(sm_conn->sm_role)){ 1762 // responder 1763 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1764 } else { 1765 // initiator 1766 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1767 } 1768 } 1769 1770 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1771 uint8_t z = 0; 1772 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1773 // some form of passkey 1774 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1775 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1776 setup->sm_passkey_bit++; 1777 } 1778 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1779 } 1780 1781 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1782 uint8_t z = 0; 1783 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1784 // some form of passkey 1785 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1786 // sm_passkey_bit was increased before sending confirm value 1787 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1788 } 1789 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1790 } 1791 1792 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1793 1794 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1795 // calculate DHKEY 1796 sm_sc_calculate_dhkey(setup->sm_dhkey); 1797 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1798 #endif 1799 1800 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1801 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1802 return; 1803 } else { 1804 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1805 } 1806 1807 } 1808 1809 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1810 // calculate DHKCheck 1811 sm_key56_t bd_addr_master, bd_addr_slave; 1812 bd_addr_master[0] = setup->sm_m_addr_type; 1813 bd_addr_slave[0] = setup->sm_s_addr_type; 1814 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1815 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1816 uint8_t iocap_a[3]; 1817 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1818 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1819 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1820 uint8_t iocap_b[3]; 1821 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1822 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1823 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1824 if (IS_RESPONDER(sm_conn->sm_role)){ 1825 // responder 1826 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); 1827 } else { 1828 // initiator 1829 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); 1830 } 1831 } 1832 1833 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1834 // validate E = f6() 1835 sm_key56_t bd_addr_master, bd_addr_slave; 1836 bd_addr_master[0] = setup->sm_m_addr_type; 1837 bd_addr_slave[0] = setup->sm_s_addr_type; 1838 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1839 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1840 1841 uint8_t iocap_a[3]; 1842 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1843 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1844 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1845 uint8_t iocap_b[3]; 1846 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1847 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1848 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1849 if (IS_RESPONDER(sm_conn->sm_role)){ 1850 // responder 1851 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); 1852 } else { 1853 // initiator 1854 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); 1855 } 1856 } 1857 1858 1859 // 1860 // Link Key Conversion Function h6 1861 // 1862 // h6(W, keyID) = AES-CMACW(keyID) 1863 // - W is 128 bits 1864 // - keyID is 32 bits 1865 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1866 const uint16_t message_len = 4; 1867 sm_cmac_connection = sm_conn; 1868 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1869 log_info("h6 key"); 1870 log_info_hexdump(w, 16); 1871 log_info("h6 message"); 1872 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1873 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1874 } 1875 1876 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1877 // Errata Service Release to the Bluetooth Specification: ESR09 1878 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1879 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1880 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1881 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1882 } 1883 1884 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1885 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1886 } 1887 1888 #endif 1889 1890 // key management legacy connections: 1891 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1892 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1893 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1894 // - responder reconnects: responder uses LTK receveived from master 1895 1896 // key management secure connections: 1897 // - both devices store same LTK from ECDH key exchange. 1898 1899 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1900 static void sm_load_security_info(sm_connection_t * sm_connection){ 1901 int encryption_key_size; 1902 int authenticated; 1903 int authorized; 1904 1905 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1906 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1907 &encryption_key_size, &authenticated, &authorized); 1908 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1909 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1910 sm_connection->sm_connection_authenticated = authenticated; 1911 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1912 } 1913 #endif 1914 1915 #ifdef ENABLE_LE_PERIPHERAL 1916 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1917 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1918 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1919 // re-establish used key encryption size 1920 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1921 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1922 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1923 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1924 log_info("sm: received ltk request with key size %u, authenticated %u", 1925 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1926 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1927 } 1928 #endif 1929 1930 static void sm_run(void){ 1931 1932 btstack_linked_list_iterator_t it; 1933 1934 // assert that stack has already bootet 1935 if (hci_get_state() != HCI_STATE_WORKING) return; 1936 1937 // assert that we can send at least commands 1938 if (!hci_can_send_command_packet_now()) return; 1939 1940 // 1941 // non-connection related behaviour 1942 // 1943 1944 // distributed key generation 1945 switch (dkg_state){ 1946 case DKG_CALC_IRK: 1947 // already busy? 1948 if (sm_aes128_state == SM_AES128_IDLE) { 1949 // IRK = d1(IR, 1, 0) 1950 sm_key_t d1_prime; 1951 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1952 dkg_next_state(); 1953 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1954 return; 1955 } 1956 break; 1957 case DKG_CALC_DHK: 1958 // already busy? 1959 if (sm_aes128_state == SM_AES128_IDLE) { 1960 // DHK = d1(IR, 3, 0) 1961 sm_key_t d1_prime; 1962 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1963 dkg_next_state(); 1964 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1965 return; 1966 } 1967 break; 1968 default: 1969 break; 1970 } 1971 1972 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1973 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1974 #ifdef USE_SOFTWARE_ECDH_IMPLEMENTATION 1975 sm_random_start(NULL); 1976 #else 1977 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1978 hci_send_cmd(&hci_le_read_local_p256_public_key); 1979 #endif 1980 return; 1981 } 1982 #endif 1983 1984 // random address updates 1985 switch (rau_state){ 1986 case RAU_GET_RANDOM: 1987 rau_next_state(); 1988 sm_random_start(NULL); 1989 return; 1990 case RAU_GET_ENC: 1991 // already busy? 1992 if (sm_aes128_state == SM_AES128_IDLE) { 1993 sm_key_t r_prime; 1994 sm_ah_r_prime(sm_random_address, r_prime); 1995 rau_next_state(); 1996 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1997 return; 1998 } 1999 break; 2000 case RAU_SET_ADDRESS: 2001 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2002 rau_state = RAU_IDLE; 2003 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2004 return; 2005 default: 2006 break; 2007 } 2008 2009 #ifdef ENABLE_CMAC_ENGINE 2010 // CMAC 2011 switch (sm_cmac_state){ 2012 case CMAC_CALC_SUBKEYS: 2013 case CMAC_CALC_MI: 2014 case CMAC_CALC_MLAST: 2015 // already busy? 2016 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2017 sm_cmac_handle_aes_engine_ready(); 2018 return; 2019 default: 2020 break; 2021 } 2022 #endif 2023 2024 // CSRK Lookup 2025 // -- if csrk lookup ready, find connection that require csrk lookup 2026 if (sm_address_resolution_idle()){ 2027 hci_connections_get_iterator(&it); 2028 while(btstack_linked_list_iterator_has_next(&it)){ 2029 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2030 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2031 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2032 // and start lookup 2033 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); 2034 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2035 break; 2036 } 2037 } 2038 } 2039 2040 // -- if csrk lookup ready, resolved addresses for received addresses 2041 if (sm_address_resolution_idle()) { 2042 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2043 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2044 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2045 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2046 btstack_memory_sm_lookup_entry_free(entry); 2047 } 2048 } 2049 2050 // -- Continue with CSRK device lookup by public or resolvable private address 2051 if (!sm_address_resolution_idle()){ 2052 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2053 while (sm_address_resolution_test < le_device_db_max_count()){ 2054 int addr_type; 2055 bd_addr_t addr; 2056 sm_key_t irk; 2057 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2058 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2059 2060 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 2061 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2062 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2063 break; 2064 } 2065 2066 if (sm_address_resolution_addr_type == 0){ 2067 sm_address_resolution_test++; 2068 continue; 2069 } 2070 2071 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2072 2073 log_info("LE Device Lookup: calculate AH"); 2074 log_info_key("IRK", irk); 2075 2076 sm_key_t r_prime; 2077 sm_ah_r_prime(sm_address_resolution_address, r_prime); 2078 sm_address_resolution_ah_calculation_active = 1; 2079 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 2080 return; 2081 } 2082 2083 if (sm_address_resolution_test >= le_device_db_max_count()){ 2084 log_info("LE Device Lookup: not found"); 2085 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2086 } 2087 } 2088 2089 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2090 // TODO: we need to verify that nobody's already waiting for random data 2091 switch (sm_sc_oob_state){ 2092 case SM_SC_OOB_W2_GET_RANDOM_1: 2093 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM_1; 2094 sm_random_start(NULL); 2095 return; 2096 case SM_SC_OOB_W2_GET_RANDOM_2: 2097 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM_2; 2098 sm_random_start(NULL); 2099 return; 2100 case SM_SC_OOB_W2_CALC_CONFIRM: 2101 if (!sm_cmac_ready()) break; 2102 if (ec_key_generation_state != EC_KEY_GENERATION_DONE) break; 2103 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2104 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2105 break; 2106 default: 2107 break; 2108 } 2109 #endif 2110 2111 // handle basic actions that don't requires the full context 2112 hci_connections_get_iterator(&it); 2113 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2114 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2115 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2116 switch(sm_connection->sm_engine_state){ 2117 // responder side 2118 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2119 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2120 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2121 return; 2122 2123 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2124 case SM_SC_RECEIVED_LTK_REQUEST: 2125 switch (sm_connection->sm_irk_lookup_state){ 2126 case IRK_LOOKUP_FAILED: 2127 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2128 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2129 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2130 return; 2131 default: 2132 break; 2133 } 2134 break; 2135 #endif 2136 default: 2137 break; 2138 } 2139 } 2140 2141 // 2142 // active connection handling 2143 // -- use loop to handle next connection if lock on setup context is released 2144 2145 while (1) { 2146 2147 // Find connections that requires setup context and make active if no other is locked 2148 hci_connections_get_iterator(&it); 2149 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2150 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2151 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2152 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2153 int done = 1; 2154 int err; 2155 UNUSED(err); 2156 switch (sm_connection->sm_engine_state) { 2157 #ifdef ENABLE_LE_PERIPHERAL 2158 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2159 // send packet if possible, 2160 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2161 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2162 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2163 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2164 } else { 2165 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2166 } 2167 // don't lock sxetup context yet 2168 done = 0; 2169 break; 2170 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2171 sm_reset_setup(); 2172 sm_init_setup(sm_connection); 2173 // recover pairing request 2174 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2175 err = sm_stk_generation_init(sm_connection); 2176 2177 #ifdef ENABLE_TESTING_SUPPORT 2178 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2179 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2180 err = test_pairing_failure; 2181 } 2182 #endif 2183 if (err){ 2184 setup->sm_pairing_failed_reason = err; 2185 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2186 break; 2187 } 2188 sm_timeout_start(sm_connection); 2189 // generate random number first, if we need to show passkey 2190 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2191 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2192 break; 2193 } 2194 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2195 break; 2196 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2197 sm_reset_setup(); 2198 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2199 break; 2200 #endif 2201 #ifdef ENABLE_LE_CENTRAL 2202 case SM_INITIATOR_PH0_HAS_LTK: 2203 sm_reset_setup(); 2204 sm_load_security_info(sm_connection); 2205 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2206 break; 2207 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2208 sm_reset_setup(); 2209 sm_init_setup(sm_connection); 2210 sm_timeout_start(sm_connection); 2211 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2212 break; 2213 #endif 2214 2215 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2216 case SM_SC_RECEIVED_LTK_REQUEST: 2217 switch (sm_connection->sm_irk_lookup_state){ 2218 case IRK_LOOKUP_SUCCEEDED: 2219 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2220 // start using context by loading security info 2221 sm_reset_setup(); 2222 sm_load_security_info(sm_connection); 2223 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2224 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2225 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2226 break; 2227 } 2228 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2229 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2230 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2231 // don't lock setup context yet 2232 return; 2233 default: 2234 // just wait until IRK lookup is completed 2235 // don't lock setup context yet 2236 done = 0; 2237 break; 2238 } 2239 break; 2240 #endif 2241 default: 2242 done = 0; 2243 break; 2244 } 2245 if (done){ 2246 sm_active_connection_handle = sm_connection->sm_handle; 2247 log_info("sm: connection 0x%04x locked setup context as %s, state %u", sm_active_connection_handle, sm_connection->sm_role ? "responder" : "initiator", sm_connection->sm_engine_state); 2248 } 2249 } 2250 2251 // 2252 // active connection handling 2253 // 2254 2255 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2256 2257 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2258 if (!connection) { 2259 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2260 return; 2261 } 2262 2263 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 2264 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_NEEDED){ 2265 setup->sm_state_vars &= ~SM_STATE_VAR_DHKEY_NEEDED; 2266 hci_send_cmd(&hci_le_generate_dhkey, &setup->sm_peer_q[0], &setup->sm_peer_q[32]); 2267 return; 2268 } 2269 #endif 2270 2271 // assert that we could send a SM PDU - not needed for all of the following 2272 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2273 log_info("cannot send now, requesting can send now event"); 2274 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2275 return; 2276 } 2277 2278 // send keypress notifications 2279 if (setup->sm_keypress_notification){ 2280 int i; 2281 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2282 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2283 uint8_t action = 0; 2284 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2285 if (flags & (1<<i)){ 2286 int clear_flag = 1; 2287 switch (i){ 2288 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2289 case SM_KEYPRESS_PASSKEY_CLEARED: 2290 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2291 default: 2292 break; 2293 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2294 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2295 num_actions--; 2296 clear_flag = num_actions == 0; 2297 break; 2298 } 2299 if (clear_flag){ 2300 flags &= ~(1<<i); 2301 } 2302 action = i; 2303 break; 2304 } 2305 } 2306 setup->sm_keypress_notification = (num_actions << 5) | flags; 2307 2308 // send keypress notification 2309 uint8_t buffer[2]; 2310 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2311 buffer[1] = action; 2312 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2313 2314 // try 2315 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2316 return; 2317 } 2318 2319 sm_key_t plaintext; 2320 int key_distribution_flags; 2321 UNUSED(key_distribution_flags); 2322 2323 log_info("sm_run: state %u", connection->sm_engine_state); 2324 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2325 log_info("sm_run // cannot send"); 2326 } 2327 switch (connection->sm_engine_state){ 2328 2329 // general 2330 case SM_GENERAL_SEND_PAIRING_FAILED: { 2331 uint8_t buffer[2]; 2332 buffer[0] = SM_CODE_PAIRING_FAILED; 2333 buffer[1] = setup->sm_pairing_failed_reason; 2334 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2335 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2336 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2337 sm_done_for_handle(connection->sm_handle); 2338 break; 2339 } 2340 2341 // responding state 2342 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2343 case SM_SC_W2_GET_RANDOM_A: 2344 sm_random_start(connection); 2345 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2346 break; 2347 case SM_SC_W2_GET_RANDOM_B: 2348 sm_random_start(connection); 2349 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2350 break; 2351 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2352 if (!sm_cmac_ready()) break; 2353 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2354 sm_sc_calculate_local_confirm(connection); 2355 break; 2356 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2357 if (!sm_cmac_ready()) break; 2358 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2359 sm_sc_calculate_remote_confirm(connection); 2360 break; 2361 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2362 if (!sm_cmac_ready()) break; 2363 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2364 sm_sc_calculate_f6_for_dhkey_check(connection); 2365 break; 2366 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2367 if (!sm_cmac_ready()) break; 2368 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2369 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2370 break; 2371 case SM_SC_W2_CALCULATE_F5_SALT: 2372 if (!sm_cmac_ready()) break; 2373 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2374 f5_calculate_salt(connection); 2375 break; 2376 case SM_SC_W2_CALCULATE_F5_MACKEY: 2377 if (!sm_cmac_ready()) break; 2378 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2379 f5_calculate_mackey(connection); 2380 break; 2381 case SM_SC_W2_CALCULATE_F5_LTK: 2382 if (!sm_cmac_ready()) break; 2383 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2384 f5_calculate_ltk(connection); 2385 break; 2386 case SM_SC_W2_CALCULATE_G2: 2387 if (!sm_cmac_ready()) break; 2388 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2389 g2_calculate(connection); 2390 break; 2391 case SM_SC_W2_CALCULATE_H6_ILK: 2392 if (!sm_cmac_ready()) break; 2393 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2394 h6_calculate_ilk(connection); 2395 break; 2396 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2397 if (!sm_cmac_ready()) break; 2398 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2399 h6_calculate_br_edr_link_key(connection); 2400 break; 2401 #endif 2402 2403 #ifdef ENABLE_LE_CENTRAL 2404 // initiator side 2405 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2406 sm_key_t peer_ltk_flipped; 2407 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2408 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2409 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2410 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2411 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2412 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2413 return; 2414 } 2415 2416 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2417 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2418 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2419 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2420 sm_timeout_reset(connection); 2421 break; 2422 #endif 2423 2424 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2425 2426 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2427 int trigger_user_response = 0; 2428 2429 uint8_t buffer[65]; 2430 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2431 // 2432 reverse_256(&ec_q[0], &buffer[1]); 2433 reverse_256(&ec_q[32], &buffer[33]); 2434 2435 // stk generation method 2436 // passkey entry: notify app to show passkey or to request passkey 2437 switch (setup->sm_stk_generation_method){ 2438 case JUST_WORKS: 2439 case NK_BOTH_INPUT: 2440 if (IS_RESPONDER(connection->sm_role)){ 2441 // responder 2442 sm_sc_start_calculating_local_confirm(connection); 2443 } else { 2444 // initiator 2445 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2446 } 2447 break; 2448 case PK_INIT_INPUT: 2449 case PK_RESP_INPUT: 2450 case OK_BOTH_INPUT: 2451 // use random TK for display 2452 memcpy(setup->sm_ra, setup->sm_tk, 16); 2453 memcpy(setup->sm_rb, setup->sm_tk, 16); 2454 setup->sm_passkey_bit = 0; 2455 2456 if (IS_RESPONDER(connection->sm_role)){ 2457 // responder 2458 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2459 } else { 2460 // initiator 2461 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2462 } 2463 trigger_user_response = 1; 2464 break; 2465 case OOB: 2466 if (IS_RESPONDER(connection->sm_role)){ 2467 // responder 2468 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2469 } else { 2470 // initiator 2471 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2472 } 2473 break; 2474 } 2475 2476 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2477 sm_timeout_reset(connection); 2478 2479 // trigger user response after sending pdu 2480 if (trigger_user_response){ 2481 sm_trigger_user_response(connection); 2482 } 2483 break; 2484 } 2485 case SM_SC_SEND_CONFIRMATION: { 2486 uint8_t buffer[17]; 2487 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2488 reverse_128(setup->sm_local_confirm, &buffer[1]); 2489 if (IS_RESPONDER(connection->sm_role)){ 2490 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2491 } else { 2492 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2493 } 2494 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2495 sm_timeout_reset(connection); 2496 break; 2497 } 2498 case SM_SC_SEND_PAIRING_RANDOM: { 2499 uint8_t buffer[17]; 2500 buffer[0] = SM_CODE_PAIRING_RANDOM; 2501 reverse_128(setup->sm_local_nonce, &buffer[1]); 2502 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2503 if (IS_RESPONDER(connection->sm_role)){ 2504 // responder 2505 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2506 } else { 2507 // initiator 2508 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2509 } 2510 } else { 2511 if (IS_RESPONDER(connection->sm_role)){ 2512 // responder 2513 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2514 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2515 } else { 2516 sm_sc_prepare_dhkey_check(connection); 2517 } 2518 } else { 2519 // initiator 2520 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2521 } 2522 } 2523 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2524 sm_timeout_reset(connection); 2525 break; 2526 } 2527 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2528 uint8_t buffer[17]; 2529 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2530 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2531 2532 if (IS_RESPONDER(connection->sm_role)){ 2533 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2534 } else { 2535 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2536 } 2537 2538 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2539 sm_timeout_reset(connection); 2540 break; 2541 } 2542 2543 #endif 2544 2545 #ifdef ENABLE_LE_PERIPHERAL 2546 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2547 // echo initiator for now 2548 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2549 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2550 2551 if (setup->sm_use_secure_connections){ 2552 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2553 // skip LTK/EDIV for SC 2554 log_info("sm: dropping encryption information flag"); 2555 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2556 } else { 2557 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2558 } 2559 2560 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); 2561 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); 2562 // update key distribution after ENC was dropped 2563 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2564 2565 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2566 sm_timeout_reset(connection); 2567 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2568 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2569 sm_trigger_user_response(connection); 2570 } 2571 return; 2572 #endif 2573 2574 case SM_PH2_SEND_PAIRING_RANDOM: { 2575 uint8_t buffer[17]; 2576 buffer[0] = SM_CODE_PAIRING_RANDOM; 2577 reverse_128(setup->sm_local_random, &buffer[1]); 2578 if (IS_RESPONDER(connection->sm_role)){ 2579 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2580 } else { 2581 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2582 } 2583 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2584 sm_timeout_reset(connection); 2585 break; 2586 } 2587 2588 case SM_PH2_GET_RANDOM_TK: 2589 case SM_PH2_C1_GET_RANDOM_A: 2590 case SM_PH2_C1_GET_RANDOM_B: 2591 case SM_PH3_GET_RANDOM: 2592 case SM_PH3_GET_DIV: 2593 sm_next_responding_state(connection); 2594 sm_random_start(connection); 2595 return; 2596 2597 case SM_PH2_C1_GET_ENC_B: 2598 case SM_PH2_C1_GET_ENC_D: 2599 // already busy? 2600 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2601 sm_next_responding_state(connection); 2602 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2603 return; 2604 2605 case SM_PH3_LTK_GET_ENC: 2606 case SM_RESPONDER_PH4_LTK_GET_ENC: 2607 // already busy? 2608 if (sm_aes128_state == SM_AES128_IDLE) { 2609 sm_key_t d_prime; 2610 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2611 sm_next_responding_state(connection); 2612 sm_aes128_start(sm_persistent_er, d_prime, connection); 2613 return; 2614 } 2615 break; 2616 2617 case SM_PH3_CSRK_GET_ENC: 2618 // already busy? 2619 if (sm_aes128_state == SM_AES128_IDLE) { 2620 sm_key_t d_prime; 2621 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2622 sm_next_responding_state(connection); 2623 sm_aes128_start(sm_persistent_er, d_prime, connection); 2624 return; 2625 } 2626 break; 2627 2628 case SM_PH2_C1_GET_ENC_C: 2629 // already busy? 2630 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2631 // calculate m_confirm using aes128 engine - step 1 2632 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); 2633 sm_next_responding_state(connection); 2634 sm_aes128_start(setup->sm_tk, plaintext, connection); 2635 break; 2636 case SM_PH2_C1_GET_ENC_A: 2637 // already busy? 2638 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2639 // calculate confirm using aes128 engine - step 1 2640 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); 2641 sm_next_responding_state(connection); 2642 sm_aes128_start(setup->sm_tk, plaintext, connection); 2643 break; 2644 case SM_PH2_CALC_STK: 2645 // already busy? 2646 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2647 // calculate STK 2648 if (IS_RESPONDER(connection->sm_role)){ 2649 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2650 } else { 2651 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2652 } 2653 sm_next_responding_state(connection); 2654 sm_aes128_start(setup->sm_tk, plaintext, connection); 2655 break; 2656 case SM_PH3_Y_GET_ENC: 2657 // already busy? 2658 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2659 // PH3B2 - calculate Y from - enc 2660 // Y = dm(DHK, Rand) 2661 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2662 sm_next_responding_state(connection); 2663 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2664 return; 2665 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2666 uint8_t buffer[17]; 2667 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2668 reverse_128(setup->sm_local_confirm, &buffer[1]); 2669 if (IS_RESPONDER(connection->sm_role)){ 2670 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2671 } else { 2672 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2673 } 2674 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2675 sm_timeout_reset(connection); 2676 return; 2677 } 2678 #ifdef ENABLE_LE_PERIPHERAL 2679 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2680 sm_key_t stk_flipped; 2681 reverse_128(setup->sm_ltk, stk_flipped); 2682 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2683 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2684 return; 2685 } 2686 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2687 sm_key_t ltk_flipped; 2688 reverse_128(setup->sm_ltk, ltk_flipped); 2689 connection->sm_engine_state = SM_RESPONDER_IDLE; 2690 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2691 sm_done_for_handle(connection->sm_handle); 2692 return; 2693 } 2694 case SM_RESPONDER_PH4_Y_GET_ENC: 2695 // already busy? 2696 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2697 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2698 // Y = dm(DHK, Rand) 2699 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2700 sm_next_responding_state(connection); 2701 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2702 return; 2703 #endif 2704 #ifdef ENABLE_LE_CENTRAL 2705 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2706 sm_key_t stk_flipped; 2707 reverse_128(setup->sm_ltk, stk_flipped); 2708 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2709 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2710 return; 2711 } 2712 #endif 2713 2714 case SM_PH3_DISTRIBUTE_KEYS: 2715 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2716 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2717 uint8_t buffer[17]; 2718 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2719 reverse_128(setup->sm_ltk, &buffer[1]); 2720 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2721 sm_timeout_reset(connection); 2722 return; 2723 } 2724 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2725 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2726 uint8_t buffer[11]; 2727 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2728 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2729 reverse_64(setup->sm_local_rand, &buffer[3]); 2730 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2731 sm_timeout_reset(connection); 2732 return; 2733 } 2734 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2735 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2736 uint8_t buffer[17]; 2737 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2738 reverse_128(sm_persistent_irk, &buffer[1]); 2739 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2740 sm_timeout_reset(connection); 2741 return; 2742 } 2743 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2744 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2745 bd_addr_t local_address; 2746 uint8_t buffer[8]; 2747 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2748 switch (gap_random_address_get_mode()){ 2749 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2750 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2751 // public or static random 2752 gap_le_get_own_address(&buffer[1], local_address); 2753 break; 2754 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2755 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2756 // fallback to public 2757 gap_local_bd_addr(local_address); 2758 buffer[1] = 0; 2759 break; 2760 } 2761 reverse_bd_addr(local_address, &buffer[2]); 2762 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2763 sm_timeout_reset(connection); 2764 return; 2765 } 2766 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2767 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2768 2769 // hack to reproduce test runs 2770 if (test_use_fixed_local_csrk){ 2771 memset(setup->sm_local_csrk, 0xcc, 16); 2772 } 2773 2774 uint8_t buffer[17]; 2775 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2776 reverse_128(setup->sm_local_csrk, &buffer[1]); 2777 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2778 sm_timeout_reset(connection); 2779 return; 2780 } 2781 2782 // keys are sent 2783 if (IS_RESPONDER(connection->sm_role)){ 2784 // slave -> receive master keys if any 2785 if (sm_key_distribution_all_received(connection)){ 2786 sm_key_distribution_handle_all_received(connection); 2787 connection->sm_engine_state = SM_RESPONDER_IDLE; 2788 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2789 sm_done_for_handle(connection->sm_handle); 2790 } else { 2791 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2792 } 2793 } else { 2794 // master -> all done 2795 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2796 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2797 sm_done_for_handle(connection->sm_handle); 2798 } 2799 break; 2800 2801 default: 2802 break; 2803 } 2804 2805 // check again if active connection was released 2806 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2807 } 2808 } 2809 2810 // note: aes engine is ready as we just got the aes result 2811 static void sm_handle_encryption_result(uint8_t * data){ 2812 2813 sm_aes128_state = SM_AES128_IDLE; 2814 2815 if (sm_address_resolution_ah_calculation_active){ 2816 sm_address_resolution_ah_calculation_active = 0; 2817 // compare calulated address against connecting device 2818 uint8_t hash[3]; 2819 reverse_24(data, hash); 2820 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2821 log_info("LE Device Lookup: matched resolvable private address"); 2822 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2823 return; 2824 } 2825 // no match, try next 2826 sm_address_resolution_test++; 2827 return; 2828 } 2829 2830 switch (dkg_state){ 2831 case DKG_W4_IRK: 2832 reverse_128(data, sm_persistent_irk); 2833 log_info_key("irk", sm_persistent_irk); 2834 dkg_next_state(); 2835 return; 2836 case DKG_W4_DHK: 2837 reverse_128(data, sm_persistent_dhk); 2838 log_info_key("dhk", sm_persistent_dhk); 2839 dkg_next_state(); 2840 // SM Init Finished 2841 return; 2842 default: 2843 break; 2844 } 2845 2846 switch (rau_state){ 2847 case RAU_W4_ENC: 2848 reverse_24(data, &sm_random_address[3]); 2849 rau_next_state(); 2850 return; 2851 default: 2852 break; 2853 } 2854 2855 #ifdef ENABLE_CMAC_ENGINE 2856 switch (sm_cmac_state){ 2857 case CMAC_W4_SUBKEYS: 2858 case CMAC_W4_MI: 2859 case CMAC_W4_MLAST: 2860 { 2861 sm_key_t t; 2862 reverse_128(data, t); 2863 sm_cmac_handle_encryption_result(t); 2864 } 2865 return; 2866 default: 2867 break; 2868 } 2869 #endif 2870 2871 // retrieve sm_connection provided to sm_aes128_start_encryption 2872 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2873 if (!connection) return; 2874 switch (connection->sm_engine_state){ 2875 case SM_PH2_C1_W4_ENC_A: 2876 case SM_PH2_C1_W4_ENC_C: 2877 { 2878 sm_key_t t2; 2879 reverse_128(data, t2); 2880 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2881 } 2882 sm_next_responding_state(connection); 2883 return; 2884 case SM_PH2_C1_W4_ENC_B: 2885 reverse_128(data, setup->sm_local_confirm); 2886 log_info_key("c1!", setup->sm_local_confirm); 2887 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2888 return; 2889 case SM_PH2_C1_W4_ENC_D: 2890 { 2891 sm_key_t peer_confirm_test; 2892 reverse_128(data, peer_confirm_test); 2893 log_info_key("c1!", peer_confirm_test); 2894 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2895 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2896 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2897 return; 2898 } 2899 if (IS_RESPONDER(connection->sm_role)){ 2900 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2901 } else { 2902 connection->sm_engine_state = SM_PH2_CALC_STK; 2903 } 2904 } 2905 return; 2906 case SM_PH2_W4_STK: 2907 reverse_128(data, setup->sm_ltk); 2908 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2909 log_info_key("stk", setup->sm_ltk); 2910 if (IS_RESPONDER(connection->sm_role)){ 2911 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2912 } else { 2913 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2914 } 2915 return; 2916 case SM_PH3_Y_W4_ENC:{ 2917 sm_key_t y128; 2918 reverse_128(data, y128); 2919 setup->sm_local_y = big_endian_read_16(y128, 14); 2920 log_info_hex16("y", setup->sm_local_y); 2921 // PH3B3 - calculate EDIV 2922 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2923 log_info_hex16("ediv", setup->sm_local_ediv); 2924 // PH3B4 - calculate LTK - enc 2925 // LTK = d1(ER, DIV, 0)) 2926 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2927 return; 2928 } 2929 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2930 sm_key_t y128; 2931 reverse_128(data, y128); 2932 setup->sm_local_y = big_endian_read_16(y128, 14); 2933 log_info_hex16("y", setup->sm_local_y); 2934 2935 // PH3B3 - calculate DIV 2936 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2937 log_info_hex16("ediv", setup->sm_local_ediv); 2938 // PH3B4 - calculate LTK - enc 2939 // LTK = d1(ER, DIV, 0)) 2940 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2941 return; 2942 } 2943 case SM_PH3_LTK_W4_ENC: 2944 reverse_128(data, setup->sm_ltk); 2945 log_info_key("ltk", setup->sm_ltk); 2946 // calc CSRK next 2947 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2948 return; 2949 case SM_PH3_CSRK_W4_ENC: 2950 reverse_128(data, setup->sm_local_csrk); 2951 log_info_key("csrk", setup->sm_local_csrk); 2952 if (setup->sm_key_distribution_send_set){ 2953 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2954 } else { 2955 // no keys to send, just continue 2956 if (IS_RESPONDER(connection->sm_role)){ 2957 // slave -> receive master keys 2958 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2959 } else { 2960 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2961 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2962 } else { 2963 // master -> all done 2964 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2965 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2966 sm_done_for_handle(connection->sm_handle); 2967 } 2968 } 2969 } 2970 return; 2971 #ifdef ENABLE_LE_PERIPHERAL 2972 case SM_RESPONDER_PH4_LTK_W4_ENC: 2973 reverse_128(data, setup->sm_ltk); 2974 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2975 log_info_key("ltk", setup->sm_ltk); 2976 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2977 return; 2978 #endif 2979 default: 2980 break; 2981 } 2982 } 2983 2984 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2985 2986 #if (defined(USE_MICRO_ECC_FOR_ECDH) && !defined(WICED_VERSION)) || defined(USE_MBEDTLS_FOR_ECDH) 2987 // @return OK 2988 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2989 if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; 2990 int offset = setup->sm_passkey_bit; 2991 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2992 while (size) { 2993 *buffer++ = setup->sm_peer_q[offset++]; 2994 size--; 2995 } 2996 setup->sm_passkey_bit = offset; 2997 return 1; 2998 } 2999 #endif 3000 #ifdef USE_MBEDTLS_FOR_ECDH 3001 // @return error - just wrap sm_generate_f_rng 3002 static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ 3003 UNUSED(context); 3004 return sm_generate_f_rng(buffer, size) == 0; 3005 } 3006 #endif /* USE_MBEDTLS_FOR_ECDH */ 3007 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 3008 3009 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 3010 static void sm_handle_random_result(uint8_t * data){ 3011 3012 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3013 3014 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 3015 int num_bytes = setup->sm_passkey_bit; 3016 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 3017 num_bytes += 8; 3018 setup->sm_passkey_bit = num_bytes; 3019 3020 if (num_bytes >= 64){ 3021 3022 // init pre-generated random data from sm_peer_q 3023 setup->sm_passkey_bit = 0; 3024 3025 // generate EC key 3026 #ifdef USE_MICRO_ECC_FOR_ECDH 3027 3028 #ifndef WICED_VERSION 3029 log_info("set uECC RNG for initial key generation with 64 random bytes"); 3030 // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it 3031 uECC_set_rng(&sm_generate_f_rng); 3032 #endif /* WICED_VERSION */ 3033 3034 #if uECC_SUPPORTS_secp256r1 3035 // standard version 3036 uECC_make_key(ec_q, ec_d, uECC_secp256r1()); 3037 3038 // disable RNG again, as returning no randmon data lets shared key generation fail 3039 log_info("disable uECC RNG in standard version after key generation"); 3040 uECC_set_rng(NULL); 3041 #else 3042 // static version 3043 uECC_make_key(ec_q, ec_d); 3044 #endif 3045 #endif /* USE_MICRO_ECC_FOR_ECDH */ 3046 3047 #ifdef USE_MBEDTLS_FOR_ECDH 3048 mbedtls_mpi d; 3049 mbedtls_ecp_point P; 3050 mbedtls_mpi_init(&d); 3051 mbedtls_ecp_point_init(&P); 3052 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); 3053 log_info("gen keypair %x", res); 3054 mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); 3055 mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); 3056 mbedtls_mpi_write_binary(&d, ec_d, 32); 3057 mbedtls_ecp_point_free(&P); 3058 mbedtls_mpi_free(&d); 3059 #endif /* USE_MBEDTLS_FOR_ECDH */ 3060 3061 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3062 log_info("Elliptic curve: d"); 3063 log_info_hexdump(ec_d,32); 3064 sm_log_ec_keypair(); 3065 } 3066 } 3067 #endif 3068 3069 switch (rau_state){ 3070 case RAU_W4_RANDOM: 3071 // non-resolvable vs. resolvable 3072 switch (gap_random_adress_type){ 3073 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3074 // resolvable: use random as prand and calc address hash 3075 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3076 memcpy(sm_random_address, data, 3); 3077 sm_random_address[0] &= 0x3f; 3078 sm_random_address[0] |= 0x40; 3079 rau_state = RAU_GET_ENC; 3080 break; 3081 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3082 default: 3083 // "The two most significant bits of the address shall be equal to ‘0’"" 3084 memcpy(sm_random_address, data, 6); 3085 sm_random_address[0] &= 0x3f; 3086 rau_state = RAU_SET_ADDRESS; 3087 break; 3088 } 3089 return; 3090 default: 3091 break; 3092 } 3093 3094 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3095 switch (sm_sc_oob_state){ 3096 case SM_SC_OOB_W4_RANDOM_1: 3097 memcpy(&sm_sc_oob_random[0], data, 8); 3098 sm_sc_oob_state = SM_SC_OOB_W2_GET_RANDOM_2; 3099 return; 3100 case SM_SC_OOB_W4_RANDOM_2: 3101 memcpy(&sm_sc_oob_random[8], data, 8); 3102 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 3103 return; 3104 default: 3105 break; 3106 } 3107 #endif 3108 3109 // retrieve sm_connection provided to sm_random_start 3110 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 3111 if (!connection) return; 3112 switch (connection->sm_engine_state){ 3113 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3114 case SM_SC_W4_GET_RANDOM_A: 3115 memcpy(&setup->sm_local_nonce[0], data, 8); 3116 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 3117 break; 3118 case SM_SC_W4_GET_RANDOM_B: 3119 memcpy(&setup->sm_local_nonce[8], data, 8); 3120 // OOB 3121 if (setup->sm_stk_generation_method == OOB){ 3122 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3123 break; 3124 } 3125 // initiator & jw/nc -> send pairing random 3126 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3127 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3128 break; 3129 } else { 3130 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3131 } 3132 break; 3133 #endif 3134 3135 case SM_PH2_W4_RANDOM_TK: 3136 { 3137 sm_reset_tk(); 3138 uint32_t tk; 3139 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3140 // map random to 0-999999 without speding much cycles on a modulus operation 3141 tk = little_endian_read_32(data,0); 3142 tk = tk & 0xfffff; // 1048575 3143 if (tk >= 999999){ 3144 tk = tk - 999999; 3145 } 3146 } else { 3147 // override with pre-defined passkey 3148 tk = sm_fixed_passkey_in_display_role; 3149 } 3150 big_endian_store_32(setup->sm_tk, 12, tk); 3151 if (IS_RESPONDER(connection->sm_role)){ 3152 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3153 } else { 3154 if (setup->sm_use_secure_connections){ 3155 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3156 } else { 3157 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3158 sm_trigger_user_response(connection); 3159 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3160 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3161 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3162 } 3163 } 3164 } 3165 return; 3166 } 3167 case SM_PH2_C1_W4_RANDOM_A: 3168 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 3169 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 3170 return; 3171 case SM_PH2_C1_W4_RANDOM_B: 3172 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 3173 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3174 return; 3175 case SM_PH3_W4_RANDOM: 3176 reverse_64(data, setup->sm_local_rand); 3177 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3178 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 3179 // no db for authenticated flag hack: store flag in bit 4 of LSB 3180 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 3181 connection->sm_engine_state = SM_PH3_GET_DIV; 3182 return; 3183 case SM_PH3_W4_DIV: 3184 // use 16 bit from random value as div 3185 setup->sm_local_div = big_endian_read_16(data, 0); 3186 log_info_hex16("div", setup->sm_local_div); 3187 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3188 return; 3189 default: 3190 break; 3191 } 3192 } 3193 3194 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3195 3196 UNUSED(channel); // ok: there is no channel 3197 UNUSED(size); // ok: fixed format HCI events 3198 3199 sm_connection_t * sm_conn; 3200 hci_con_handle_t con_handle; 3201 3202 switch (packet_type) { 3203 3204 case HCI_EVENT_PACKET: 3205 switch (hci_event_packet_get_type(packet)) { 3206 3207 case BTSTACK_EVENT_STATE: 3208 // bt stack activated, get started 3209 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3210 log_info("HCI Working!"); 3211 3212 3213 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 3214 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3215 if (!sm_have_ec_keypair){ 3216 setup->sm_passkey_bit = 0; 3217 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3218 } 3219 #endif 3220 // trigger Random Address generation if requested before 3221 switch (gap_random_adress_type){ 3222 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3223 rau_state = RAU_IDLE; 3224 break; 3225 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 3226 rau_state = RAU_SET_ADDRESS; 3227 break; 3228 default: 3229 rau_state = RAU_GET_RANDOM; 3230 break; 3231 } 3232 sm_run(); 3233 } 3234 break; 3235 3236 case HCI_EVENT_LE_META: 3237 switch (packet[2]) { 3238 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3239 3240 log_info("sm: connected"); 3241 3242 if (packet[3]) return; // connection failed 3243 3244 con_handle = little_endian_read_16(packet, 4); 3245 sm_conn = sm_get_connection_for_handle(con_handle); 3246 if (!sm_conn) break; 3247 3248 sm_conn->sm_handle = con_handle; 3249 sm_conn->sm_role = packet[6]; 3250 sm_conn->sm_peer_addr_type = packet[7]; 3251 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3252 3253 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3254 3255 // reset security properties 3256 sm_conn->sm_connection_encrypted = 0; 3257 sm_conn->sm_connection_authenticated = 0; 3258 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3259 sm_conn->sm_le_db_index = -1; 3260 3261 // prepare CSRK lookup (does not involve setup) 3262 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3263 3264 // just connected -> everything else happens in sm_run() 3265 if (IS_RESPONDER(sm_conn->sm_role)){ 3266 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3267 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3268 if (sm_slave_request_security) { 3269 // request security if requested by app 3270 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3271 } else { 3272 // otherwise, wait for pairing request 3273 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3274 } 3275 } 3276 break; 3277 } else { 3278 // master 3279 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3280 } 3281 break; 3282 3283 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3284 con_handle = little_endian_read_16(packet, 3); 3285 sm_conn = sm_get_connection_for_handle(con_handle); 3286 if (!sm_conn) break; 3287 3288 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3289 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3290 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3291 break; 3292 } 3293 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3294 // PH2 SEND LTK as we need to exchange keys in PH3 3295 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3296 break; 3297 } 3298 3299 // store rand and ediv 3300 reverse_64(&packet[5], sm_conn->sm_local_rand); 3301 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3302 3303 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3304 // potentially stored LTK is from the master 3305 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3306 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3307 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3308 break; 3309 } 3310 // additionally check if remote is in LE Device DB if requested 3311 switch(sm_conn->sm_irk_lookup_state){ 3312 case IRK_LOOKUP_FAILED: 3313 log_info("LTK Request: device not in device db"); 3314 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3315 break; 3316 case IRK_LOOKUP_SUCCEEDED: 3317 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3318 break; 3319 default: 3320 // wait for irk look doen 3321 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3322 break; 3323 } 3324 break; 3325 } 3326 3327 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3328 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3329 #else 3330 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3331 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3332 #endif 3333 break; 3334 3335 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3336 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3337 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3338 log_error("Read Local P256 Public Key failed"); 3339 break; 3340 } 3341 3342 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3343 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3344 3345 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3346 sm_log_ec_keypair(); 3347 break; 3348 case HCI_SUBEVENT_LE_GENERATE_DHKEY_COMPLETE: 3349 sm_conn = sm_get_connection_for_handle(sm_active_connection_handle); 3350 if (hci_subevent_le_generate_dhkey_complete_get_status(packet)){ 3351 log_error("Generate DHKEY failed -> abort"); 3352 // abort pairing with 'unspecified reason' 3353 sm_pdu_received_in_wrong_state(sm_conn); 3354 break; 3355 } 3356 3357 hci_subevent_le_generate_dhkey_complete_get_dhkey(packet, &setup->sm_dhkey[0]); 3358 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 3359 log_info("dhkey"); 3360 log_info_hexdump(&setup->sm_dhkey[0], 32); 3361 3362 // trigger next step 3363 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 3364 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 3365 } 3366 break; 3367 #endif 3368 default: 3369 break; 3370 } 3371 break; 3372 3373 case HCI_EVENT_ENCRYPTION_CHANGE: 3374 con_handle = little_endian_read_16(packet, 3); 3375 sm_conn = sm_get_connection_for_handle(con_handle); 3376 if (!sm_conn) break; 3377 3378 sm_conn->sm_connection_encrypted = packet[5]; 3379 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3380 sm_conn->sm_actual_encryption_key_size); 3381 log_info("event handler, state %u", sm_conn->sm_engine_state); 3382 if (!sm_conn->sm_connection_encrypted) break; 3383 // continue if part of initial pairing 3384 switch (sm_conn->sm_engine_state){ 3385 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3386 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3387 sm_done_for_handle(sm_conn->sm_handle); 3388 break; 3389 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3390 if (IS_RESPONDER(sm_conn->sm_role)){ 3391 // slave 3392 if (setup->sm_use_secure_connections){ 3393 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3394 } else { 3395 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3396 } 3397 } else { 3398 // master 3399 if (sm_key_distribution_all_received(sm_conn)){ 3400 // skip receiving keys as there are none 3401 sm_key_distribution_handle_all_received(sm_conn); 3402 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3403 } else { 3404 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3405 } 3406 } 3407 break; 3408 default: 3409 break; 3410 } 3411 break; 3412 3413 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3414 con_handle = little_endian_read_16(packet, 3); 3415 sm_conn = sm_get_connection_for_handle(con_handle); 3416 if (!sm_conn) break; 3417 3418 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3419 log_info("event handler, state %u", sm_conn->sm_engine_state); 3420 // continue if part of initial pairing 3421 switch (sm_conn->sm_engine_state){ 3422 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3423 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3424 sm_done_for_handle(sm_conn->sm_handle); 3425 break; 3426 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3427 if (IS_RESPONDER(sm_conn->sm_role)){ 3428 // slave 3429 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3430 } else { 3431 // master 3432 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3433 } 3434 break; 3435 default: 3436 break; 3437 } 3438 break; 3439 3440 3441 case HCI_EVENT_DISCONNECTION_COMPLETE: 3442 con_handle = little_endian_read_16(packet, 3); 3443 sm_done_for_handle(con_handle); 3444 sm_conn = sm_get_connection_for_handle(con_handle); 3445 if (!sm_conn) break; 3446 3447 // delete stored bonding on disconnect with authentication failure in ph0 3448 if (sm_conn->sm_role == 0 3449 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3450 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3451 le_device_db_remove(sm_conn->sm_le_db_index); 3452 } 3453 3454 // pairing failed, if it was ongoing 3455 if (sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED && sm_conn->sm_engine_state != SM_GENERAL_IDLE){ 3456 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3457 } 3458 3459 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3460 sm_conn->sm_handle = 0; 3461 break; 3462 3463 case HCI_EVENT_COMMAND_COMPLETE: 3464 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3465 sm_handle_encryption_result(&packet[6]); 3466 break; 3467 } 3468 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3469 sm_handle_random_result(&packet[6]); 3470 break; 3471 } 3472 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3473 // set local addr for le device db 3474 bd_addr_t addr; 3475 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3476 le_device_db_set_local_bd_addr(addr); 3477 } 3478 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_local_supported_commands)){ 3479 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(USE_SOFTWARE_ECDH_IMPLEMENTATION) 3480 if ((packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE+1+34] & 0x06) != 0x06){ 3481 // mbedTLS can also be used if already available (and malloc is supported) 3482 log_error("LE Secure Connections enabled, but HCI Controller doesn't support it. Please add USE_MICRO_ECC_FOR_ECDH to btstack_config.h"); 3483 } 3484 #endif 3485 } 3486 break; 3487 default: 3488 break; 3489 } 3490 break; 3491 default: 3492 break; 3493 } 3494 3495 sm_run(); 3496 } 3497 3498 static inline int sm_calc_actual_encryption_key_size(int other){ 3499 if (other < sm_min_encryption_key_size) return 0; 3500 if (other < sm_max_encryption_key_size) return other; 3501 return sm_max_encryption_key_size; 3502 } 3503 3504 3505 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3506 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3507 switch (method){ 3508 case JUST_WORKS: 3509 case NK_BOTH_INPUT: 3510 return 1; 3511 default: 3512 return 0; 3513 } 3514 } 3515 // responder 3516 3517 static int sm_passkey_used(stk_generation_method_t method){ 3518 switch (method){ 3519 case PK_RESP_INPUT: 3520 return 1; 3521 default: 3522 return 0; 3523 } 3524 } 3525 #endif 3526 3527 /** 3528 * @return ok 3529 */ 3530 static int sm_validate_stk_generation_method(void){ 3531 // check if STK generation method is acceptable by client 3532 switch (setup->sm_stk_generation_method){ 3533 case JUST_WORKS: 3534 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3535 case PK_RESP_INPUT: 3536 case PK_INIT_INPUT: 3537 case OK_BOTH_INPUT: 3538 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3539 case OOB: 3540 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3541 case NK_BOTH_INPUT: 3542 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3543 return 1; 3544 default: 3545 return 0; 3546 } 3547 } 3548 3549 // size of complete sm_pdu used to validate input 3550 static const uint8_t sm_pdu_size[] = { 3551 0, // 0x00 invalid opcode 3552 7, // 0x01 pairing request 3553 7, // 0x02 pairing response 3554 17, // 0x03 pairing confirm 3555 17, // 0x04 pairing random 3556 2, // 0x05 pairing failed 3557 17, // 0x06 encryption information 3558 11, // 0x07 master identification 3559 17, // 0x08 identification information 3560 8, // 0x09 identify address information 3561 17, // 0x0a signing information 3562 2, // 0x0b security request 3563 65, // 0x0c pairing public key 3564 17, // 0x0d pairing dhk check 3565 2, // 0x0e keypress notification 3566 }; 3567 3568 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3569 3570 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3571 sm_run(); 3572 } 3573 3574 if (packet_type != SM_DATA_PACKET) return; 3575 if (size == 0) return; 3576 3577 uint8_t sm_pdu_code = packet[0]; 3578 3579 // validate pdu size 3580 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3581 if (sm_pdu_size[sm_pdu_code] != size) return; 3582 3583 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3584 if (!sm_conn) return; 3585 3586 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3587 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3588 sm_done_for_handle(con_handle); 3589 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3590 return; 3591 } 3592 3593 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3594 3595 int err; 3596 UNUSED(err); 3597 3598 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3599 uint8_t buffer[5]; 3600 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3601 buffer[1] = 3; 3602 little_endian_store_16(buffer, 2, con_handle); 3603 buffer[4] = packet[1]; 3604 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3605 return; 3606 } 3607 3608 switch (sm_conn->sm_engine_state){ 3609 3610 // a sm timeout requries a new physical connection 3611 case SM_GENERAL_TIMEOUT: 3612 return; 3613 3614 #ifdef ENABLE_LE_CENTRAL 3615 3616 // Initiator 3617 case SM_INITIATOR_CONNECTED: 3618 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3619 sm_pdu_received_in_wrong_state(sm_conn); 3620 break; 3621 } 3622 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3623 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3624 break; 3625 } 3626 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3627 sm_key_t ltk; 3628 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3629 if (!sm_is_null_key(ltk)){ 3630 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3631 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3632 } else { 3633 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3634 } 3635 break; 3636 } 3637 // otherwise, store security request 3638 sm_conn->sm_security_request_received = 1; 3639 break; 3640 3641 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3642 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3643 sm_pdu_received_in_wrong_state(sm_conn); 3644 break; 3645 } 3646 3647 // store pairing request 3648 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3649 err = sm_stk_generation_init(sm_conn); 3650 3651 #ifdef ENABLE_TESTING_SUPPORT 3652 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3653 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3654 err = test_pairing_failure; 3655 } 3656 #endif 3657 3658 if (err){ 3659 setup->sm_pairing_failed_reason = err; 3660 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3661 break; 3662 } 3663 3664 // generate random number first, if we need to show passkey 3665 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3666 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3667 break; 3668 } 3669 3670 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3671 if (setup->sm_use_secure_connections){ 3672 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3673 if (setup->sm_stk_generation_method == JUST_WORKS){ 3674 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3675 sm_trigger_user_response(sm_conn); 3676 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3677 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3678 } 3679 } else { 3680 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3681 } 3682 break; 3683 } 3684 #endif 3685 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3686 sm_trigger_user_response(sm_conn); 3687 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3688 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3689 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3690 } 3691 break; 3692 3693 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3694 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3695 sm_pdu_received_in_wrong_state(sm_conn); 3696 break; 3697 } 3698 3699 // store s_confirm 3700 reverse_128(&packet[1], setup->sm_peer_confirm); 3701 3702 #ifdef ENABLE_TESTING_SUPPORT 3703 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3704 log_info("testing_support: reset confirm value"); 3705 memset(setup->sm_peer_confirm, 0, 16); 3706 } 3707 #endif 3708 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3709 break; 3710 3711 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3712 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3713 sm_pdu_received_in_wrong_state(sm_conn); 3714 break;; 3715 } 3716 3717 // received random value 3718 reverse_128(&packet[1], setup->sm_peer_random); 3719 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3720 break; 3721 #endif 3722 3723 #ifdef ENABLE_LE_PERIPHERAL 3724 // Responder 3725 case SM_RESPONDER_IDLE: 3726 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3727 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3728 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3729 sm_pdu_received_in_wrong_state(sm_conn); 3730 break;; 3731 } 3732 3733 // store pairing request 3734 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3735 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3736 break; 3737 #endif 3738 3739 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3740 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3741 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3742 sm_pdu_received_in_wrong_state(sm_conn); 3743 break; 3744 } 3745 3746 // store public key for DH Key calculation 3747 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3748 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3749 3750 // validate public key using micro-ecc 3751 err = 0; 3752 3753 #ifdef USE_MICRO_ECC_FOR_ECDH 3754 #if uECC_SUPPORTS_secp256r1 3755 // standard version 3756 err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0; 3757 #else 3758 // static version 3759 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3760 #endif 3761 #endif 3762 3763 #ifdef USE_MBEDTLS_FOR_ECDH 3764 mbedtls_ecp_point Q; 3765 mbedtls_ecp_point_init( &Q ); 3766 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); 3767 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 3768 mbedtls_mpi_lset(&Q.Z, 1); 3769 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3770 mbedtls_ecp_point_free( & Q); 3771 #endif 3772 3773 if (err){ 3774 log_error("sm: peer public key invalid %x", err); 3775 // uses "unspecified reason", there is no "public key invalid" error code 3776 sm_pdu_received_in_wrong_state(sm_conn); 3777 break; 3778 } 3779 3780 #ifndef USE_SOFTWARE_ECDH_IMPLEMENTATION 3781 // ask controller to calculate dhkey 3782 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_NEEDED; 3783 #endif 3784 3785 3786 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3787 if (IS_RESPONDER(sm_conn->sm_role)){ 3788 // responder 3789 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3790 } else { 3791 // initiator 3792 // stk generation method 3793 // passkey entry: notify app to show passkey or to request passkey 3794 switch (setup->sm_stk_generation_method){ 3795 case JUST_WORKS: 3796 case NK_BOTH_INPUT: 3797 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3798 break; 3799 case PK_RESP_INPUT: 3800 sm_sc_start_calculating_local_confirm(sm_conn); 3801 break; 3802 case PK_INIT_INPUT: 3803 case OK_BOTH_INPUT: 3804 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3805 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3806 break; 3807 } 3808 sm_sc_start_calculating_local_confirm(sm_conn); 3809 break; 3810 case OOB: 3811 // generate Nx 3812 log_info("Generate Nx"); 3813 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3814 break; 3815 } 3816 } 3817 break; 3818 3819 case SM_SC_W4_CONFIRMATION: 3820 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3821 sm_pdu_received_in_wrong_state(sm_conn); 3822 break; 3823 } 3824 // received confirm value 3825 reverse_128(&packet[1], setup->sm_peer_confirm); 3826 3827 #ifdef ENABLE_TESTING_SUPPORT 3828 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3829 log_info("testing_support: reset confirm value"); 3830 memset(setup->sm_peer_confirm, 0, 16); 3831 } 3832 #endif 3833 if (IS_RESPONDER(sm_conn->sm_role)){ 3834 // responder 3835 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3836 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3837 // still waiting for passkey 3838 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3839 break; 3840 } 3841 } 3842 sm_sc_start_calculating_local_confirm(sm_conn); 3843 } else { 3844 // initiator 3845 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3846 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3847 } else { 3848 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3849 } 3850 } 3851 break; 3852 3853 case SM_SC_W4_PAIRING_RANDOM: 3854 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3855 sm_pdu_received_in_wrong_state(sm_conn); 3856 break; 3857 } 3858 3859 // received random value 3860 reverse_128(&packet[1], setup->sm_peer_nonce); 3861 3862 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3863 // only check for JUST WORK/NC in initiator role OR passkey entry 3864 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3865 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3866 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3867 break; 3868 } 3869 3870 sm_sc_state_after_receiving_random(sm_conn); 3871 break; 3872 3873 case SM_SC_W2_CALCULATE_G2: 3874 case SM_SC_W4_CALCULATE_G2: 3875 case SM_SC_W4_CALCULATE_DHKEY: 3876 case SM_SC_W2_CALCULATE_F5_SALT: 3877 case SM_SC_W4_CALCULATE_F5_SALT: 3878 case SM_SC_W2_CALCULATE_F5_MACKEY: 3879 case SM_SC_W4_CALCULATE_F5_MACKEY: 3880 case SM_SC_W2_CALCULATE_F5_LTK: 3881 case SM_SC_W4_CALCULATE_F5_LTK: 3882 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3883 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3884 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3885 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3886 sm_pdu_received_in_wrong_state(sm_conn); 3887 break; 3888 } 3889 // store DHKey Check 3890 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3891 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3892 3893 // have we been only waiting for dhkey check command? 3894 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3895 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3896 } 3897 break; 3898 #endif 3899 3900 #ifdef ENABLE_LE_PERIPHERAL 3901 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3902 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3903 sm_pdu_received_in_wrong_state(sm_conn); 3904 break; 3905 } 3906 3907 // received confirm value 3908 reverse_128(&packet[1], setup->sm_peer_confirm); 3909 3910 #ifdef ENABLE_TESTING_SUPPORT 3911 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3912 log_info("testing_support: reset confirm value"); 3913 memset(setup->sm_peer_confirm, 0, 16); 3914 } 3915 #endif 3916 // notify client to hide shown passkey 3917 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3918 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3919 } 3920 3921 // handle user cancel pairing? 3922 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3923 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3924 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3925 break; 3926 } 3927 3928 // wait for user action? 3929 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3930 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3931 break; 3932 } 3933 3934 // calculate and send local_confirm 3935 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3936 break; 3937 3938 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3939 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3940 sm_pdu_received_in_wrong_state(sm_conn); 3941 break;; 3942 } 3943 3944 // received random value 3945 reverse_128(&packet[1], setup->sm_peer_random); 3946 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3947 break; 3948 #endif 3949 3950 case SM_PH3_RECEIVE_KEYS: 3951 switch(sm_pdu_code){ 3952 case SM_CODE_ENCRYPTION_INFORMATION: 3953 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3954 reverse_128(&packet[1], setup->sm_peer_ltk); 3955 break; 3956 3957 case SM_CODE_MASTER_IDENTIFICATION: 3958 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3959 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3960 reverse_64(&packet[3], setup->sm_peer_rand); 3961 break; 3962 3963 case SM_CODE_IDENTITY_INFORMATION: 3964 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3965 reverse_128(&packet[1], setup->sm_peer_irk); 3966 break; 3967 3968 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3969 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3970 setup->sm_peer_addr_type = packet[1]; 3971 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3972 break; 3973 3974 case SM_CODE_SIGNING_INFORMATION: 3975 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3976 reverse_128(&packet[1], setup->sm_peer_csrk); 3977 break; 3978 default: 3979 // Unexpected PDU 3980 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3981 break; 3982 } 3983 // done with key distribution? 3984 if (sm_key_distribution_all_received(sm_conn)){ 3985 3986 sm_key_distribution_handle_all_received(sm_conn); 3987 3988 if (IS_RESPONDER(sm_conn->sm_role)){ 3989 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3990 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3991 } else { 3992 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3993 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3994 sm_done_for_handle(sm_conn->sm_handle); 3995 } 3996 } else { 3997 if (setup->sm_use_secure_connections){ 3998 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3999 } else { 4000 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 4001 } 4002 } 4003 } 4004 break; 4005 default: 4006 // Unexpected PDU 4007 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4008 break; 4009 } 4010 4011 // try to send preparared packet 4012 sm_run(); 4013 } 4014 4015 // Security Manager Client API 4016 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 4017 sm_get_oob_data = get_oob_data_callback; 4018 } 4019 4020 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4021 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4022 } 4023 4024 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4025 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4026 } 4027 4028 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4029 sm_min_encryption_key_size = min_size; 4030 sm_max_encryption_key_size = max_size; 4031 } 4032 4033 void sm_set_authentication_requirements(uint8_t auth_req){ 4034 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4035 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4036 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4037 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4038 } 4039 #endif 4040 sm_auth_req = auth_req; 4041 } 4042 4043 void sm_set_io_capabilities(io_capability_t io_capability){ 4044 sm_io_capabilities = io_capability; 4045 } 4046 4047 #ifdef ENABLE_LE_PERIPHERAL 4048 void sm_set_request_security(int enable){ 4049 sm_slave_request_security = enable; 4050 } 4051 #endif 4052 4053 void sm_set_er(sm_key_t er){ 4054 memcpy(sm_persistent_er, er, 16); 4055 } 4056 4057 void sm_set_ir(sm_key_t ir){ 4058 memcpy(sm_persistent_ir, ir, 16); 4059 } 4060 4061 // Testing support only 4062 void sm_test_set_irk(sm_key_t irk){ 4063 memcpy(sm_persistent_irk, irk, 16); 4064 sm_persistent_irk_ready = 1; 4065 } 4066 4067 void sm_test_use_fixed_local_csrk(void){ 4068 test_use_fixed_local_csrk = 1; 4069 } 4070 4071 #ifdef ENABLE_TESTING_SUPPORT 4072 void sm_test_set_pairing_failure(int reason){ 4073 test_pairing_failure = reason; 4074 } 4075 #endif 4076 4077 void sm_init(void){ 4078 // set some (BTstack default) ER and IR 4079 int i; 4080 sm_key_t er; 4081 sm_key_t ir; 4082 for (i=0;i<16;i++){ 4083 er[i] = 0x30 + i; 4084 ir[i] = 0x90 + i; 4085 } 4086 sm_set_er(er); 4087 sm_set_ir(ir); 4088 // defaults 4089 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4090 | SM_STK_GENERATION_METHOD_OOB 4091 | SM_STK_GENERATION_METHOD_PASSKEY 4092 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4093 4094 sm_max_encryption_key_size = 16; 4095 sm_min_encryption_key_size = 7; 4096 4097 sm_fixed_passkey_in_display_role = 0xffffffff; 4098 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4099 4100 #ifdef ENABLE_CMAC_ENGINE 4101 sm_cmac_state = CMAC_IDLE; 4102 #endif 4103 dkg_state = DKG_W4_WORKING; 4104 rau_state = RAU_W4_WORKING; 4105 sm_aes128_state = SM_AES128_IDLE; 4106 sm_address_resolution_test = -1; // no private address to resolve yet 4107 sm_address_resolution_ah_calculation_active = 0; 4108 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4109 sm_address_resolution_general_queue = NULL; 4110 4111 gap_random_adress_update_period = 15 * 60 * 1000L; 4112 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4113 4114 test_use_fixed_local_csrk = 0; 4115 4116 // register for HCI Events from HCI 4117 hci_event_callback_registration.callback = &sm_event_packet_handler; 4118 hci_add_event_handler(&hci_event_callback_registration); 4119 4120 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4121 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4122 4123 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4124 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 4125 #endif 4126 4127 #ifdef USE_MBEDTLS_FOR_ECDH 4128 mbedtls_ecp_group_init(&mbedtls_ec_group); 4129 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 4130 #endif 4131 } 4132 4133 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 4134 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4135 memcpy(&ec_q[0], qx, 32); 4136 memcpy(&ec_q[32], qy, 32); 4137 memcpy(ec_d, d, 32); 4138 sm_have_ec_keypair = 1; 4139 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4140 #else 4141 UNUSED(qx); 4142 UNUSED(qy); 4143 UNUSED(d); 4144 #endif 4145 } 4146 4147 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4148 static void parse_hex(uint8_t * buffer, const char * hex_string){ 4149 while (*hex_string){ 4150 int high_nibble = nibble_for_char(*hex_string++); 4151 int low_nibble = nibble_for_char(*hex_string++); 4152 *buffer++ = (high_nibble << 4) | low_nibble; 4153 } 4154 } 4155 #endif 4156 4157 void sm_test_use_fixed_ec_keypair(void){ 4158 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4159 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 4160 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 4161 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 4162 parse_hex(ec_d, ec_d_string); 4163 parse_hex(&ec_q[0], ec_qx_string); 4164 parse_hex(&ec_q[32], ec_qy_string); 4165 sm_have_ec_keypair = 1; 4166 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4167 #endif 4168 } 4169 4170 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4171 sm_fixed_passkey_in_display_role = passkey; 4172 } 4173 4174 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4175 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4176 } 4177 4178 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4179 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4180 if (!hci_con) return NULL; 4181 return &hci_con->sm_connection; 4182 } 4183 4184 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4185 switch (sm_conn->sm_engine_state){ 4186 case SM_GENERAL_IDLE: 4187 case SM_RESPONDER_IDLE: 4188 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4189 sm_run(); 4190 break; 4191 default: 4192 break; 4193 } 4194 } 4195 4196 /** 4197 * @brief Trigger Security Request 4198 */ 4199 void sm_send_security_request(hci_con_handle_t con_handle){ 4200 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4201 if (!sm_conn) return; 4202 sm_send_security_request_for_connection(sm_conn); 4203 } 4204 4205 // request pairing 4206 void sm_request_pairing(hci_con_handle_t con_handle){ 4207 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4208 if (!sm_conn) return; // wrong connection 4209 4210 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4211 if (IS_RESPONDER(sm_conn->sm_role)){ 4212 sm_send_security_request_for_connection(sm_conn); 4213 } else { 4214 // used as a trigger to start central/master/initiator security procedures 4215 uint16_t ediv; 4216 sm_key_t ltk; 4217 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4218 switch (sm_conn->sm_irk_lookup_state){ 4219 case IRK_LOOKUP_FAILED: 4220 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4221 break; 4222 case IRK_LOOKUP_SUCCEEDED: 4223 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 4224 if (!sm_is_null_key(ltk) || ediv){ 4225 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 4226 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4227 } else { 4228 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4229 } 4230 break; 4231 default: 4232 sm_conn->sm_pairing_requested = 1; 4233 break; 4234 } 4235 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4236 sm_conn->sm_pairing_requested = 1; 4237 } 4238 } 4239 sm_run(); 4240 } 4241 4242 // called by client app on authorization request 4243 void sm_authorization_decline(hci_con_handle_t con_handle){ 4244 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4245 if (!sm_conn) return; // wrong connection 4246 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4247 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4248 } 4249 4250 void sm_authorization_grant(hci_con_handle_t con_handle){ 4251 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4252 if (!sm_conn) return; // wrong connection 4253 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4254 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4255 } 4256 4257 // GAP Bonding API 4258 4259 void sm_bonding_decline(hci_con_handle_t con_handle){ 4260 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4261 if (!sm_conn) return; // wrong connection 4262 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4263 log_info("decline, state %u", sm_conn->sm_engine_state); 4264 switch(sm_conn->sm_engine_state){ 4265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4266 case SM_SC_W4_USER_RESPONSE: 4267 case SM_SC_W4_CONFIRMATION: 4268 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4269 #endif 4270 case SM_PH1_W4_USER_RESPONSE: 4271 switch (setup->sm_stk_generation_method){ 4272 case PK_RESP_INPUT: 4273 case PK_INIT_INPUT: 4274 case OK_BOTH_INPUT: 4275 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4276 break; 4277 case NK_BOTH_INPUT: 4278 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4279 break; 4280 case JUST_WORKS: 4281 case OOB: 4282 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4283 break; 4284 } 4285 break; 4286 default: 4287 break; 4288 } 4289 sm_run(); 4290 } 4291 4292 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4293 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4294 if (!sm_conn) return; // wrong connection 4295 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4296 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4297 if (setup->sm_use_secure_connections){ 4298 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4299 } else { 4300 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4301 } 4302 } 4303 4304 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4305 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4306 sm_sc_prepare_dhkey_check(sm_conn); 4307 } 4308 #endif 4309 4310 sm_run(); 4311 } 4312 4313 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4314 // for now, it's the same 4315 sm_just_works_confirm(con_handle); 4316 } 4317 4318 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4319 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4320 if (!sm_conn) return; // wrong connection 4321 sm_reset_tk(); 4322 big_endian_store_32(setup->sm_tk, 12, passkey); 4323 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4324 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4325 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 4326 } 4327 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4328 memcpy(setup->sm_ra, setup->sm_tk, 16); 4329 memcpy(setup->sm_rb, setup->sm_tk, 16); 4330 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4331 sm_sc_start_calculating_local_confirm(sm_conn); 4332 } 4333 #endif 4334 sm_run(); 4335 } 4336 4337 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4338 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4339 if (!sm_conn) return; // wrong connection 4340 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4341 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4342 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4343 switch (action){ 4344 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4345 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4346 flags |= (1 << action); 4347 break; 4348 case SM_KEYPRESS_PASSKEY_CLEARED: 4349 // clear counter, keypress & erased flags + set passkey cleared 4350 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4351 break; 4352 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4353 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4354 // erase actions queued 4355 num_actions--; 4356 if (num_actions == 0){ 4357 // clear counter, keypress & erased flags 4358 flags &= 0x19; 4359 } 4360 break; 4361 } 4362 num_actions++; 4363 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4364 break; 4365 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4366 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4367 // enter actions queued 4368 num_actions--; 4369 if (num_actions == 0){ 4370 // clear counter, keypress & erased flags 4371 flags &= 0x19; 4372 } 4373 break; 4374 } 4375 num_actions++; 4376 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4377 break; 4378 default: 4379 break; 4380 } 4381 setup->sm_keypress_notification = (num_actions << 5) | flags; 4382 sm_run(); 4383 } 4384 4385 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4386 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4387 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4388 sm_sc_oob_callback = callback; 4389 sm_sc_oob_state = SM_SC_OOB_W2_GET_RANDOM_1; 4390 sm_run(); 4391 return 0; 4392 } 4393 #endif 4394 4395 /** 4396 * @brief Identify device in LE Device DB 4397 * @param handle 4398 * @returns index from le_device_db or -1 if not found/identified 4399 */ 4400 int sm_le_device_index(hci_con_handle_t con_handle ){ 4401 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4402 if (!sm_conn) return -1; 4403 return sm_conn->sm_le_db_index; 4404 } 4405 4406 static int gap_random_address_type_requires_updates(void){ 4407 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4408 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4409 return 1; 4410 } 4411 4412 static uint8_t own_address_type(void){ 4413 switch (gap_random_adress_type){ 4414 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4415 return BD_ADDR_TYPE_LE_PUBLIC; 4416 default: 4417 return BD_ADDR_TYPE_LE_RANDOM; 4418 } 4419 } 4420 4421 // GAP LE API 4422 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4423 gap_random_address_update_stop(); 4424 gap_random_adress_type = random_address_type; 4425 hci_le_set_own_address_type(own_address_type()); 4426 if (!gap_random_address_type_requires_updates()) return; 4427 gap_random_address_update_start(); 4428 gap_random_address_trigger(); 4429 } 4430 4431 gap_random_address_type_t gap_random_address_get_mode(void){ 4432 return gap_random_adress_type; 4433 } 4434 4435 void gap_random_address_set_update_period(int period_ms){ 4436 gap_random_adress_update_period = period_ms; 4437 if (!gap_random_address_type_requires_updates()) return; 4438 gap_random_address_update_stop(); 4439 gap_random_address_update_start(); 4440 } 4441 4442 void gap_random_address_set(bd_addr_t addr){ 4443 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4444 memcpy(sm_random_address, addr, 6); 4445 if (rau_state == RAU_W4_WORKING) return; 4446 rau_state = RAU_SET_ADDRESS; 4447 sm_run(); 4448 } 4449 4450 #ifdef ENABLE_LE_PERIPHERAL 4451 /* 4452 * @brief Set Advertisement Paramters 4453 * @param adv_int_min 4454 * @param adv_int_max 4455 * @param adv_type 4456 * @param direct_address_type 4457 * @param direct_address 4458 * @param channel_map 4459 * @param filter_policy 4460 * 4461 * @note own_address_type is used from gap_random_address_set_mode 4462 */ 4463 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4464 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4465 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4466 direct_address_typ, direct_address, channel_map, filter_policy); 4467 } 4468 #endif 4469