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 <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_crypto.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "btstack_tlv.h" 53 #include "gap.h" 54 #include "hci.h" 55 #include "hci_dump.h" 56 #include "l2cap.h" 57 58 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 59 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 60 #endif 61 62 // assert SM Public Key can be sent/received 63 #ifdef ENABLE_LE_SECURE_CONNECTIONS 64 #if HCI_ACL_PAYLOAD_SIZE < 69 65 #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" 66 #endif 67 #endif 68 69 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 70 #define IS_RESPONDER(role) (role) 71 #else 72 #ifdef ENABLE_LE_CENTRAL 73 // only central - never responder (avoid 'unused variable' warnings) 74 #define IS_RESPONDER(role) (0 && role) 75 #else 76 // only peripheral - always responder (avoid 'unused variable' warnings) 77 #define IS_RESPONDER(role) (1 || role) 78 #endif 79 #endif 80 81 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 82 #define USE_CMAC_ENGINE 83 #endif 84 85 #define BTSTACK_TAG32(A,B,C,D) ((A << 24) | (B << 16) | (C << 8) | D) 86 87 // 88 // SM internal types and globals 89 // 90 91 typedef enum { 92 DKG_W4_WORKING, 93 DKG_CALC_IRK, 94 DKG_CALC_DHK, 95 DKG_READY 96 } derived_key_generation_t; 97 98 typedef enum { 99 RAU_IDLE, 100 RAU_GET_RANDOM, 101 RAU_W4_RANDOM, 102 RAU_GET_ENC, 103 RAU_W4_ENC, 104 RAU_SET_ADDRESS, 105 } random_address_update_t; 106 107 typedef enum { 108 CMAC_IDLE, 109 CMAC_CALC_SUBKEYS, 110 CMAC_W4_SUBKEYS, 111 CMAC_CALC_MI, 112 CMAC_W4_MI, 113 CMAC_CALC_MLAST, 114 CMAC_W4_MLAST 115 } cmac_state_t; 116 117 typedef enum { 118 JUST_WORKS, 119 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 120 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 121 PK_BOTH_INPUT, // Only input on both, both input PK 122 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 123 OOB // OOB available on one (SC) or both sides (legacy) 124 } stk_generation_method_t; 125 126 typedef enum { 127 SM_USER_RESPONSE_IDLE, 128 SM_USER_RESPONSE_PENDING, 129 SM_USER_RESPONSE_CONFIRM, 130 SM_USER_RESPONSE_PASSKEY, 131 SM_USER_RESPONSE_DECLINE 132 } sm_user_response_t; 133 134 typedef enum { 135 SM_AES128_IDLE, 136 SM_AES128_ACTIVE 137 } sm_aes128_state_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_IDLE, 141 ADDRESS_RESOLUTION_GENERAL, 142 ADDRESS_RESOLUTION_FOR_CONNECTION, 143 } address_resolution_mode_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_SUCEEDED, 147 ADDRESS_RESOLUTION_FAILED, 148 } address_resolution_event_t; 149 150 typedef enum { 151 EC_KEY_GENERATION_IDLE, 152 EC_KEY_GENERATION_ACTIVE, 153 EC_KEY_GENERATION_DONE, 154 } ec_key_generation_state_t; 155 156 typedef enum { 157 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 158 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 159 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 160 } sm_state_var_t; 161 162 typedef enum { 163 SM_SC_OOB_IDLE, 164 SM_SC_OOB_W4_RANDOM, 165 SM_SC_OOB_W2_CALC_CONFIRM, 166 SM_SC_OOB_W4_CONFIRM, 167 } sm_sc_oob_state_t; 168 169 typedef uint8_t sm_key24_t[3]; 170 typedef uint8_t sm_key56_t[7]; 171 typedef uint8_t sm_key256_t[32]; 172 173 // 174 // GLOBAL DATA 175 // 176 177 static uint8_t test_use_fixed_local_csrk; 178 179 #ifdef ENABLE_TESTING_SUPPORT 180 static uint8_t test_pairing_failure; 181 #endif 182 183 // configuration 184 static uint8_t sm_accepted_stk_generation_methods; 185 static uint8_t sm_max_encryption_key_size; 186 static uint8_t sm_min_encryption_key_size; 187 static uint8_t sm_auth_req = 0; 188 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 189 static uint8_t sm_slave_request_security; 190 static uint32_t sm_fixed_passkey_in_display_role; 191 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 192 193 #ifdef ENABLE_LE_SECURE_CONNECTIONS 194 static uint8_t sm_sc_oob_random[16]; 195 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 196 static sm_sc_oob_state_t sm_sc_oob_state; 197 #endif 198 199 200 static uint8_t sm_persistent_keys_random_active; 201 static const btstack_tlv_t * sm_tlv_impl; 202 static void * sm_tlv_context; 203 204 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 205 static sm_key_t sm_persistent_er; 206 static sm_key_t sm_persistent_ir; 207 208 // derived from sm_persistent_ir 209 static sm_key_t sm_persistent_dhk; 210 static sm_key_t sm_persistent_irk; 211 static derived_key_generation_t dkg_state; 212 213 // derived from sm_persistent_er 214 // .. 215 216 // random address update 217 static random_address_update_t rau_state; 218 static bd_addr_t sm_random_address; 219 220 #ifdef USE_CMAC_ENGINE 221 // CMAC Calculation: General 222 static btstack_crypto_aes128_cmac_t sm_cmac_request; 223 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 224 static uint8_t sm_cmac_active; 225 static uint8_t sm_cmac_hash[16]; 226 #endif 227 228 // CMAC for ATT Signed Writes 229 #ifdef ENABLE_LE_SIGNED_WRITE 230 static uint16_t sm_cmac_signed_write_message_len; 231 static uint8_t sm_cmac_signed_write_header[3]; 232 static const uint8_t * sm_cmac_signed_write_message; 233 static uint8_t sm_cmac_signed_write_sign_counter[4]; 234 #endif 235 236 // CMAC for Secure Connection functions 237 #ifdef ENABLE_LE_SECURE_CONNECTIONS 238 static sm_connection_t * sm_cmac_connection; 239 static uint8_t sm_cmac_sc_buffer[80]; 240 #endif 241 242 // resolvable private address lookup / CSRK calculation 243 static int sm_address_resolution_test; 244 static int sm_address_resolution_ah_calculation_active; 245 static uint8_t sm_address_resolution_addr_type; 246 static bd_addr_t sm_address_resolution_address; 247 static void * sm_address_resolution_context; 248 static address_resolution_mode_t sm_address_resolution_mode; 249 static btstack_linked_list_t sm_address_resolution_general_queue; 250 251 // aes128 crypto engine. 252 static sm_aes128_state_t sm_aes128_state; 253 254 // crypto 255 static btstack_crypto_random_t sm_crypto_random_request; 256 static btstack_crypto_aes128_t sm_crypto_aes128_request; 257 #ifdef ENABLE_LE_SECURE_CONNECTIONS 258 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 259 static btstack_crypto_random_t sm_crypto_random_oob_request; 260 #endif 261 262 // temp storage for random data 263 static uint8_t sm_random_data[8]; 264 static uint8_t sm_aes128_key[16]; 265 static uint8_t sm_aes128_plaintext[16]; 266 static uint8_t sm_aes128_ciphertext[16]; 267 268 // to receive hci events 269 static btstack_packet_callback_registration_t hci_event_callback_registration; 270 271 /* to dispatch sm event */ 272 static btstack_linked_list_t sm_event_handlers; 273 274 // LE Secure Connections 275 #ifdef ENABLE_LE_SECURE_CONNECTIONS 276 static ec_key_generation_state_t ec_key_generation_state; 277 static uint8_t ec_q[64]; 278 #endif 279 280 // 281 // Volume 3, Part H, Chapter 24 282 // "Security shall be initiated by the Security Manager in the device in the master role. 283 // The device in the slave role shall be the responding device." 284 // -> master := initiator, slave := responder 285 // 286 287 // data needed for security setup 288 typedef struct sm_setup_context { 289 290 btstack_timer_source_t sm_timeout; 291 292 // used in all phases 293 uint8_t sm_pairing_failed_reason; 294 295 // user response, (Phase 1 and/or 2) 296 uint8_t sm_user_response; 297 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 298 299 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 300 int sm_key_distribution_send_set; 301 int sm_key_distribution_received_set; 302 303 // Phase 2 (Pairing over SMP) 304 stk_generation_method_t sm_stk_generation_method; 305 sm_key_t sm_tk; 306 uint8_t sm_have_oob_data; 307 uint8_t sm_use_secure_connections; 308 309 sm_key_t sm_c1_t3_value; // c1 calculation 310 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 311 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 312 sm_key_t sm_local_random; 313 sm_key_t sm_local_confirm; 314 sm_key_t sm_peer_random; 315 sm_key_t sm_peer_confirm; 316 uint8_t sm_m_addr_type; // address and type can be removed 317 uint8_t sm_s_addr_type; // '' 318 bd_addr_t sm_m_address; // '' 319 bd_addr_t sm_s_address; // '' 320 sm_key_t sm_ltk; 321 322 uint8_t sm_state_vars; 323 #ifdef ENABLE_LE_SECURE_CONNECTIONS 324 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 325 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 326 sm_key_t sm_local_nonce; // might be combined with sm_local_random 327 sm_key_t sm_dhkey; 328 sm_key_t sm_peer_dhkey_check; 329 sm_key_t sm_local_dhkey_check; 330 sm_key_t sm_ra; 331 sm_key_t sm_rb; 332 sm_key_t sm_t; // used for f5 and h6 333 sm_key_t sm_mackey; 334 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 335 #endif 336 337 // Phase 3 338 339 // key distribution, we generate 340 uint16_t sm_local_y; 341 uint16_t sm_local_div; 342 uint16_t sm_local_ediv; 343 uint8_t sm_local_rand[8]; 344 sm_key_t sm_local_ltk; 345 sm_key_t sm_local_csrk; 346 sm_key_t sm_local_irk; 347 // sm_local_address/addr_type not needed 348 349 // key distribution, received from peer 350 uint16_t sm_peer_y; 351 uint16_t sm_peer_div; 352 uint16_t sm_peer_ediv; 353 uint8_t sm_peer_rand[8]; 354 sm_key_t sm_peer_ltk; 355 sm_key_t sm_peer_irk; 356 sm_key_t sm_peer_csrk; 357 uint8_t sm_peer_addr_type; 358 bd_addr_t sm_peer_address; 359 360 } sm_setup_context_t; 361 362 // 363 static sm_setup_context_t the_setup; 364 static sm_setup_context_t * setup = &the_setup; 365 366 // active connection - the one for which the_setup is used for 367 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 368 369 // @returns 1 if oob data is available 370 // stores oob data in provided 16 byte buffer if not null 371 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 372 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 373 374 // horizontal: initiator capabilities 375 // vertial: responder capabilities 376 static const stk_generation_method_t stk_generation_method [5] [5] = { 377 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 378 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 379 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 380 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 381 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 382 }; 383 384 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 385 #ifdef ENABLE_LE_SECURE_CONNECTIONS 386 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 387 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 388 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 389 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 390 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 391 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 392 }; 393 #endif 394 395 static void sm_run(void); 396 #ifdef USE_CMAC_ENGINE 397 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 398 #endif 399 static void sm_done_for_handle(hci_con_handle_t con_handle); 400 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 401 static inline int sm_calc_actual_encryption_key_size(int other); 402 static int sm_validate_stk_generation_method(void); 403 static void sm_handle_encryption_result_address_resolution(void *arg); 404 static void sm_handle_encryption_result_dkg_dhk(void *arg); 405 static void sm_handle_encryption_result_dkg_irk(void *arg); 406 static void sm_handle_encryption_result_enc_a(void *arg); 407 static void sm_handle_encryption_result_enc_b(void *arg); 408 static void sm_handle_encryption_result_enc_c(void *arg); 409 static void sm_handle_encryption_result_enc_csrk(void *arg); 410 static void sm_handle_encryption_result_enc_d(void * arg); 411 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 412 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 413 #ifdef ENABLE_LE_PERIPHERAL 414 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 415 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 416 #endif 417 static void sm_handle_encryption_result_enc_stk(void *arg); 418 static void sm_handle_encryption_result_rau(void *arg); 419 static void sm_handle_random_result_ph2_tk(void * arg); 420 static void sm_handle_random_result_rau(void * arg); 421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 422 static void sm_ec_generate_new_key(void); 423 static void sm_handle_random_result_sc_get_random(void * arg); 424 static int sm_passkey_entry(stk_generation_method_t method); 425 #endif 426 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 427 428 static void log_info_hex16(const char * name, uint16_t value){ 429 log_info("%-6s 0x%04x", name, value); 430 } 431 432 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 433 // return packet[0]; 434 // } 435 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 436 return packet[1]; 437 } 438 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 439 return packet[2]; 440 } 441 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 442 return packet[3]; 443 } 444 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 445 return packet[4]; 446 } 447 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 448 return packet[5]; 449 } 450 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 451 return packet[6]; 452 } 453 454 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 455 packet[0] = code; 456 } 457 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 458 packet[1] = io_capability; 459 } 460 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 461 packet[2] = oob_data_flag; 462 } 463 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 464 packet[3] = auth_req; 465 } 466 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 467 packet[4] = max_encryption_key_size; 468 } 469 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 470 packet[5] = initiator_key_distribution; 471 } 472 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 473 packet[6] = responder_key_distribution; 474 } 475 476 // @returns 1 if all bytes are 0 477 static int sm_is_null(uint8_t * data, int size){ 478 int i; 479 for (i=0; i < size ; i++){ 480 if (data[i]) return 0; 481 } 482 return 1; 483 } 484 485 static int sm_is_null_random(uint8_t random[8]){ 486 return sm_is_null(random, 8); 487 } 488 489 static int sm_is_null_key(uint8_t * key){ 490 return sm_is_null(key, 16); 491 } 492 493 // Key utils 494 static void sm_reset_tk(void){ 495 int i; 496 for (i=0;i<16;i++){ 497 setup->sm_tk[i] = 0; 498 } 499 } 500 501 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 502 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 503 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 504 int i; 505 for (i = max_encryption_size ; i < 16 ; i++){ 506 key[15-i] = 0; 507 } 508 } 509 510 // ER / IR checks 511 static void sm_er_ir_set_default(void){ 512 int i; 513 for (i=0;i<16;i++){ 514 sm_persistent_er[i] = 0x30 + i; 515 sm_persistent_ir[i] = 0x90 + i; 516 } 517 } 518 519 static int sm_er_is_default(void){ 520 int i; 521 for (i=0;i<16;i++){ 522 if (sm_persistent_er[i] != (0x30+i)) return 0; 523 } 524 return 1; 525 } 526 527 static int sm_ir_is_default(void){ 528 int i; 529 for (i=0;i<16;i++){ 530 if (sm_persistent_ir[i] != (0x90+i)) return 0; 531 } 532 return 1; 533 } 534 535 // SMP Timeout implementation 536 537 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 538 // the Security Manager Timer shall be reset and started. 539 // 540 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 541 // 542 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 543 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 544 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 545 // established. 546 547 static void sm_timeout_handler(btstack_timer_source_t * timer){ 548 log_info("SM timeout"); 549 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 550 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 551 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 552 sm_done_for_handle(sm_conn->sm_handle); 553 554 // trigger handling of next ready connection 555 sm_run(); 556 } 557 static void sm_timeout_start(sm_connection_t * sm_conn){ 558 btstack_run_loop_remove_timer(&setup->sm_timeout); 559 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 560 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 561 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 562 btstack_run_loop_add_timer(&setup->sm_timeout); 563 } 564 static void sm_timeout_stop(void){ 565 btstack_run_loop_remove_timer(&setup->sm_timeout); 566 } 567 static void sm_timeout_reset(sm_connection_t * sm_conn){ 568 sm_timeout_stop(); 569 sm_timeout_start(sm_conn); 570 } 571 572 // end of sm timeout 573 574 // GAP Random Address updates 575 static gap_random_address_type_t gap_random_adress_type; 576 static btstack_timer_source_t gap_random_address_update_timer; 577 static uint32_t gap_random_adress_update_period; 578 579 static void gap_random_address_trigger(void){ 580 log_info("gap_random_address_trigger, state %u", rau_state); 581 if (rau_state != RAU_IDLE) return; 582 rau_state = RAU_GET_RANDOM; 583 sm_run(); 584 } 585 586 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 587 UNUSED(timer); 588 589 log_info("GAP Random Address Update due"); 590 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 591 btstack_run_loop_add_timer(&gap_random_address_update_timer); 592 gap_random_address_trigger(); 593 } 594 595 static void gap_random_address_update_start(void){ 596 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 597 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 598 btstack_run_loop_add_timer(&gap_random_address_update_timer); 599 } 600 601 static void gap_random_address_update_stop(void){ 602 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 603 } 604 605 // ah(k,r) helper 606 // r = padding || r 607 // r - 24 bit value 608 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 609 // r'= padding || r 610 memset(r_prime, 0, 16); 611 memcpy(&r_prime[13], r, 3); 612 } 613 614 // d1 helper 615 // d' = padding || r || d 616 // d,r - 16 bit values 617 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 618 // d'= padding || r || d 619 memset(d1_prime, 0, 16); 620 big_endian_store_16(d1_prime, 12, r); 621 big_endian_store_16(d1_prime, 14, d); 622 } 623 624 // dm helper 625 // r’ = padding || r 626 // r - 64 bit value 627 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 628 memset(r_prime, 0, 16); 629 memcpy(&r_prime[8], r, 8); 630 } 631 632 // calculate arguments for first AES128 operation in C1 function 633 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){ 634 635 // p1 = pres || preq || rat’ || iat’ 636 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 637 // cant octet of pres becomes the most significant octet of p1. 638 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 639 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 640 // p1 is 0x05000800000302070710000001010001." 641 642 sm_key_t p1; 643 reverse_56(pres, &p1[0]); 644 reverse_56(preq, &p1[7]); 645 p1[14] = rat; 646 p1[15] = iat; 647 log_info_key("p1", p1); 648 log_info_key("r", r); 649 650 // t1 = r xor p1 651 int i; 652 for (i=0;i<16;i++){ 653 t1[i] = r[i] ^ p1[i]; 654 } 655 log_info_key("t1", t1); 656 } 657 658 // calculate arguments for second AES128 operation in C1 function 659 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 660 // p2 = padding || ia || ra 661 // "The least significant octet of ra becomes the least significant octet of p2 and 662 // the most significant octet of padding becomes the most significant octet of p2. 663 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 664 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 665 666 sm_key_t p2; 667 memset(p2, 0, 16); 668 memcpy(&p2[4], ia, 6); 669 memcpy(&p2[10], ra, 6); 670 log_info_key("p2", p2); 671 672 // c1 = e(k, t2_xor_p2) 673 int i; 674 for (i=0;i<16;i++){ 675 t3[i] = t2[i] ^ p2[i]; 676 } 677 log_info_key("t3", t3); 678 } 679 680 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 681 log_info_key("r1", r1); 682 log_info_key("r2", r2); 683 memcpy(&r_prime[8], &r2[8], 8); 684 memcpy(&r_prime[0], &r1[8], 8); 685 } 686 687 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 688 UNUSED(channel); 689 690 // log event 691 hci_dump_packet(packet_type, 1, packet, size); 692 // dispatch to all event handlers 693 btstack_linked_list_iterator_t it; 694 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 695 while (btstack_linked_list_iterator_has_next(&it)){ 696 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 697 entry->callback(packet_type, 0, packet, size); 698 } 699 } 700 701 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){ 702 event[0] = type; 703 event[1] = event_size - 2; 704 little_endian_store_16(event, 2, con_handle); 705 event[4] = addr_type; 706 reverse_bd_addr(address, &event[5]); 707 } 708 709 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 710 uint8_t event[11]; 711 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 712 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 713 } 714 715 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){ 716 uint8_t event[15]; 717 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 718 little_endian_store_32(event, 11, passkey); 719 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 720 } 721 722 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){ 723 // fetch addr and addr type from db, only called for valid entries 724 bd_addr_t identity_address; 725 int identity_address_type; 726 le_device_db_info(index, &identity_address_type, identity_address, NULL); 727 728 uint8_t event[20]; 729 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 730 event[11] = identity_address_type; 731 reverse_bd_addr(identity_address, &event[12]); 732 little_endian_store_16(event, 18, index); 733 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 734 } 735 736 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){ 737 uint8_t event[12]; 738 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 739 event[11] = status; 740 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 741 } 742 743 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 744 uint8_t event[13]; 745 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 746 event[11] = status; 747 event[12] = reason; 748 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 749 } 750 751 // decide on stk generation based on 752 // - pairing request 753 // - io capabilities 754 // - OOB data availability 755 static void sm_setup_tk(void){ 756 757 // default: just works 758 setup->sm_stk_generation_method = JUST_WORKS; 759 760 #ifdef ENABLE_LE_SECURE_CONNECTIONS 761 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 762 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 763 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 764 #else 765 setup->sm_use_secure_connections = 0; 766 #endif 767 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 768 769 770 // decide if OOB will be used based on SC vs. Legacy and oob flags 771 int use_oob = 0; 772 if (setup->sm_use_secure_connections){ 773 // In LE Secure Connections pairing, the out of band method is used if at least 774 // one device has the peer device's out of band authentication data available. 775 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 776 } else { 777 // In LE legacy pairing, the out of band method is used if both the devices have 778 // the other device's out of band authentication data available. 779 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 780 } 781 if (use_oob){ 782 log_info("SM: have OOB data"); 783 log_info_key("OOB", setup->sm_tk); 784 setup->sm_stk_generation_method = OOB; 785 return; 786 } 787 788 // If both devices have not set the MITM option in the Authentication Requirements 789 // Flags, then the IO capabilities shall be ignored and the Just Works association 790 // model shall be used. 791 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 792 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 793 log_info("SM: MITM not required by both -> JUST WORKS"); 794 return; 795 } 796 797 // Reset TK as it has been setup in sm_init_setup 798 sm_reset_tk(); 799 800 // Also use just works if unknown io capabilites 801 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)){ 802 return; 803 } 804 805 // Otherwise the IO capabilities of the devices shall be used to determine the 806 // pairing method as defined in Table 2.4. 807 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 808 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 809 810 #ifdef ENABLE_LE_SECURE_CONNECTIONS 811 // table not define by default 812 if (setup->sm_use_secure_connections){ 813 generation_method = stk_generation_method_with_secure_connection; 814 } 815 #endif 816 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)]; 817 818 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 819 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); 820 } 821 822 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 823 int flags = 0; 824 if (key_set & SM_KEYDIST_ENC_KEY){ 825 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 826 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 827 } 828 if (key_set & SM_KEYDIST_ID_KEY){ 829 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 830 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 831 } 832 if (key_set & SM_KEYDIST_SIGN){ 833 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 834 } 835 return flags; 836 } 837 838 static void sm_setup_key_distribution(uint8_t key_set){ 839 setup->sm_key_distribution_received_set = 0; 840 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 841 } 842 843 // CSRK Key Lookup 844 845 846 static int sm_address_resolution_idle(void){ 847 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 848 } 849 850 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){ 851 memcpy(sm_address_resolution_address, addr, 6); 852 sm_address_resolution_addr_type = addr_type; 853 sm_address_resolution_test = 0; 854 sm_address_resolution_mode = mode; 855 sm_address_resolution_context = context; 856 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 857 } 858 859 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 860 // check if already in list 861 btstack_linked_list_iterator_t it; 862 sm_lookup_entry_t * entry; 863 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 864 while(btstack_linked_list_iterator_has_next(&it)){ 865 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 866 if (entry->address_type != address_type) continue; 867 if (memcmp(entry->address, address, 6)) continue; 868 // already in list 869 return BTSTACK_BUSY; 870 } 871 entry = btstack_memory_sm_lookup_entry_get(); 872 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 873 entry->address_type = (bd_addr_type_t) address_type; 874 memcpy(entry->address, address, 6); 875 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 876 sm_run(); 877 return 0; 878 } 879 880 // CMAC calculation using AES Engineq 881 #ifdef USE_CMAC_ENGINE 882 883 static void sm_cmac_done_trampoline(void * arg){ 884 UNUSED(arg); 885 sm_cmac_active = 0; 886 (*sm_cmac_done_callback)(sm_cmac_hash); 887 sm_run(); 888 } 889 890 int sm_cmac_ready(void){ 891 return sm_cmac_active == 0; 892 } 893 894 // generic cmac calculation 895 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 896 sm_cmac_active = 1; 897 sm_cmac_done_callback = done_callback; 898 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 899 } 900 #endif 901 902 // cmac for ATT Message signing 903 #ifdef ENABLE_LE_SIGNED_WRITE 904 905 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 906 sm_cmac_active = 1; 907 sm_cmac_done_callback = done_callback; 908 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 909 } 910 911 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 912 if (offset >= sm_cmac_signed_write_message_len) { 913 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 914 return 0; 915 } 916 917 offset = sm_cmac_signed_write_message_len - 1 - offset; 918 919 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 920 if (offset < 3){ 921 return sm_cmac_signed_write_header[offset]; 922 } 923 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 924 if (offset < actual_message_len_incl_header){ 925 return sm_cmac_signed_write_message[offset - 3]; 926 } 927 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 928 } 929 930 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)){ 931 // ATT Message Signing 932 sm_cmac_signed_write_header[0] = opcode; 933 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 934 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 935 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 936 sm_cmac_signed_write_message = message; 937 sm_cmac_signed_write_message_len = total_message_len; 938 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 939 } 940 #endif 941 942 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 943 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 944 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 945 switch (setup->sm_stk_generation_method){ 946 case PK_RESP_INPUT: 947 if (IS_RESPONDER(sm_conn->sm_role)){ 948 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 949 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 950 } else { 951 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)); 952 } 953 break; 954 case PK_INIT_INPUT: 955 if (IS_RESPONDER(sm_conn->sm_role)){ 956 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)); 957 } else { 958 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 959 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 960 } 961 break; 962 case PK_BOTH_INPUT: 963 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 964 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 965 break; 966 case NUMERIC_COMPARISON: 967 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 968 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)); 969 break; 970 case JUST_WORKS: 971 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 972 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 973 break; 974 case OOB: 975 // client already provided OOB data, let's skip notification. 976 break; 977 } 978 } 979 980 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 981 int recv_flags; 982 if (IS_RESPONDER(sm_conn->sm_role)){ 983 // slave / responder 984 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 985 } else { 986 // master / initiator 987 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 988 } 989 990 #ifdef ENABLE_LE_SECURE_CONNECTIONS 991 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 992 if (setup->sm_use_secure_connections){ 993 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 994 } 995 #endif 996 997 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 998 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 999 } 1000 1001 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1002 if (sm_active_connection_handle == con_handle){ 1003 sm_timeout_stop(); 1004 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1005 log_info("sm: connection 0x%x released setup context", con_handle); 1006 1007 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1008 // generate new ec key after each pairing (that used it) 1009 if (setup->sm_use_secure_connections){ 1010 sm_ec_generate_new_key(); 1011 } 1012 #endif 1013 } 1014 } 1015 1016 static int sm_key_distribution_flags_for_auth_req(void){ 1017 1018 int flags = SM_KEYDIST_ID_KEY; 1019 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1020 // encryption and signing information only if bonding requested 1021 flags |= SM_KEYDIST_ENC_KEY; 1022 #ifdef ENABLE_LE_SIGNED_WRITE 1023 flags |= SM_KEYDIST_SIGN; 1024 #endif 1025 } 1026 return flags; 1027 } 1028 1029 static void sm_reset_setup(void){ 1030 // fill in sm setup 1031 setup->sm_state_vars = 0; 1032 setup->sm_keypress_notification = 0; 1033 sm_reset_tk(); 1034 } 1035 1036 static void sm_init_setup(sm_connection_t * sm_conn){ 1037 1038 // fill in sm setup 1039 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1040 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1041 1042 // query client for Legacy Pairing OOB data 1043 setup->sm_have_oob_data = 0; 1044 if (sm_get_oob_data) { 1045 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1046 } 1047 1048 // if available and SC supported, also ask for SC OOB Data 1049 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1050 memset(setup->sm_ra, 0, 16); 1051 memset(setup->sm_rb, 0, 16); 1052 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1053 if (sm_get_sc_oob_data){ 1054 if (IS_RESPONDER(sm_conn->sm_role)){ 1055 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1056 sm_conn->sm_peer_addr_type, 1057 sm_conn->sm_peer_address, 1058 setup->sm_peer_confirm, 1059 setup->sm_ra); 1060 } else { 1061 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1062 sm_conn->sm_peer_addr_type, 1063 sm_conn->sm_peer_address, 1064 setup->sm_peer_confirm, 1065 setup->sm_rb); 1066 } 1067 } else { 1068 setup->sm_have_oob_data = 0; 1069 } 1070 } 1071 #endif 1072 1073 sm_pairing_packet_t * local_packet; 1074 if (IS_RESPONDER(sm_conn->sm_role)){ 1075 // slave 1076 local_packet = &setup->sm_s_pres; 1077 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1078 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1079 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1080 } else { 1081 // master 1082 local_packet = &setup->sm_m_preq; 1083 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1084 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1085 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1086 1087 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1088 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1089 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1090 } 1091 1092 uint8_t auth_req = sm_auth_req; 1093 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1094 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1095 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1096 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1097 } 1098 1099 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1100 1101 sm_pairing_packet_t * remote_packet; 1102 int remote_key_request; 1103 if (IS_RESPONDER(sm_conn->sm_role)){ 1104 // slave / responder 1105 remote_packet = &setup->sm_m_preq; 1106 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1107 } else { 1108 // master / initiator 1109 remote_packet = &setup->sm_s_pres; 1110 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1111 } 1112 1113 // check key size 1114 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1115 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1116 1117 // decide on STK generation method / SC 1118 sm_setup_tk(); 1119 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1120 1121 // check if STK generation method is acceptable by client 1122 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1123 1124 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1125 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1126 if (setup->sm_use_secure_connections){ 1127 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1128 } 1129 #endif 1130 1131 // identical to responder 1132 sm_setup_key_distribution(remote_key_request); 1133 1134 // JUST WORKS doens't provide authentication 1135 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1136 1137 return 0; 1138 } 1139 1140 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1141 1142 // cache and reset context 1143 int matched_device_id = sm_address_resolution_test; 1144 address_resolution_mode_t mode = sm_address_resolution_mode; 1145 void * context = sm_address_resolution_context; 1146 1147 // reset context 1148 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1149 sm_address_resolution_context = NULL; 1150 sm_address_resolution_test = -1; 1151 hci_con_handle_t con_handle = 0; 1152 1153 sm_connection_t * sm_connection; 1154 #ifdef ENABLE_LE_CENTRAL 1155 sm_key_t ltk; 1156 int have_ltk; 1157 int pairing_need; 1158 #endif 1159 switch (mode){ 1160 case ADDRESS_RESOLUTION_GENERAL: 1161 break; 1162 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1163 sm_connection = (sm_connection_t *) context; 1164 con_handle = sm_connection->sm_handle; 1165 switch (event){ 1166 case ADDRESS_RESOLUTION_SUCEEDED: 1167 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1168 sm_connection->sm_le_db_index = matched_device_id; 1169 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1170 if (sm_connection->sm_role) { 1171 // LTK request received before, IRK required -> start LTK calculation 1172 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1173 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1174 } 1175 break; 1176 } 1177 #ifdef ENABLE_LE_CENTRAL 1178 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1179 have_ltk = !sm_is_null_key(ltk); 1180 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1181 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1182 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1183 // reset requests 1184 sm_connection->sm_security_request_received = 0; 1185 sm_connection->sm_pairing_requested = 0; 1186 1187 // have ltk -> start encryption 1188 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1189 // "When a bond has been created between two devices, any reconnection should result in the local device 1190 // enabling or requesting encryption with the remote device before initiating any service request." 1191 if (have_ltk){ 1192 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1193 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1194 break; 1195 #else 1196 log_info("central: defer enabling encryption for bonded device"); 1197 #endif 1198 } 1199 // pairint_request -> send pairing request 1200 if (pairing_need){ 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1202 break; 1203 } 1204 #endif 1205 break; 1206 case ADDRESS_RESOLUTION_FAILED: 1207 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1208 if (sm_connection->sm_role) { 1209 // LTK request received before, IRK required -> negative LTK reply 1210 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1211 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1212 } 1213 break; 1214 } 1215 #ifdef ENABLE_LE_CENTRAL 1216 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1217 sm_connection->sm_security_request_received = 0; 1218 sm_connection->sm_pairing_requested = 0; 1219 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1220 #endif 1221 break; 1222 } 1223 break; 1224 default: 1225 break; 1226 } 1227 1228 switch (event){ 1229 case ADDRESS_RESOLUTION_SUCEEDED: 1230 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1231 break; 1232 case ADDRESS_RESOLUTION_FAILED: 1233 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1234 break; 1235 } 1236 } 1237 1238 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1239 1240 int le_db_index = -1; 1241 1242 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1243 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1244 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1245 & SM_AUTHREQ_BONDING ) != 0; 1246 1247 if (bonding_enabed){ 1248 1249 // lookup device based on IRK 1250 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1251 int i; 1252 for (i=0; i < le_device_db_max_count(); i++){ 1253 sm_key_t irk; 1254 bd_addr_t address; 1255 int address_type = BD_ADDR_TYPE_UNKNOWN; 1256 le_device_db_info(i, &address_type, address, irk); 1257 // skip unused entries 1258 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1259 // compare IRK 1260 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1261 1262 log_info("sm: device found for IRK, updating"); 1263 le_db_index = i; 1264 break; 1265 } 1266 } else { 1267 // assert IRK is set to zero 1268 memset(setup->sm_peer_irk, 0, 16); 1269 } 1270 1271 // if not found, lookup via public address if possible 1272 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1273 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1274 int i; 1275 for (i=0; i < le_device_db_max_count(); i++){ 1276 bd_addr_t address; 1277 int address_type = BD_ADDR_TYPE_UNKNOWN; 1278 le_device_db_info(i, &address_type, address, NULL); 1279 // skip unused entries 1280 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1281 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1282 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1283 log_info("sm: device found for public address, updating"); 1284 le_db_index = i; 1285 break; 1286 } 1287 } 1288 } 1289 1290 // if not found, add to db 1291 if (le_db_index < 0) { 1292 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1293 } 1294 1295 if (le_db_index >= 0){ 1296 1297 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1298 1299 #ifdef ENABLE_LE_SIGNED_WRITE 1300 // store local CSRK 1301 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1302 log_info("sm: store local CSRK"); 1303 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1304 le_device_db_local_counter_set(le_db_index, 0); 1305 } 1306 1307 // store remote CSRK 1308 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1309 log_info("sm: store remote CSRK"); 1310 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1311 le_device_db_remote_counter_set(le_db_index, 0); 1312 } 1313 #endif 1314 // store encryption information for secure connections: LTK generated by ECDH 1315 if (setup->sm_use_secure_connections){ 1316 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1317 uint8_t zero_rand[8]; 1318 memset(zero_rand, 0, 8); 1319 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1320 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1321 } 1322 1323 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1324 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1325 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1326 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1327 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1328 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1329 1330 } 1331 } 1332 } else { 1333 log_info("Ignoring received keys, bonding not enabled"); 1334 } 1335 1336 // keep le_db_index 1337 sm_conn->sm_le_db_index = le_db_index; 1338 } 1339 1340 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1341 setup->sm_pairing_failed_reason = reason; 1342 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1343 } 1344 1345 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1346 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1347 } 1348 1349 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1350 1351 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1352 static int sm_passkey_used(stk_generation_method_t method); 1353 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1354 1355 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1356 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1357 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1358 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1359 } else { 1360 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1361 } 1362 } 1363 1364 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1365 if (IS_RESPONDER(sm_conn->sm_role)){ 1366 // Responder 1367 if (setup->sm_stk_generation_method == OOB){ 1368 // generate Nb 1369 log_info("Generate Nb"); 1370 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1371 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1372 } else { 1373 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1374 } 1375 } else { 1376 // Initiator role 1377 switch (setup->sm_stk_generation_method){ 1378 case JUST_WORKS: 1379 sm_sc_prepare_dhkey_check(sm_conn); 1380 break; 1381 1382 case NUMERIC_COMPARISON: 1383 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1384 break; 1385 case PK_INIT_INPUT: 1386 case PK_RESP_INPUT: 1387 case PK_BOTH_INPUT: 1388 if (setup->sm_passkey_bit < 20) { 1389 sm_sc_start_calculating_local_confirm(sm_conn); 1390 } else { 1391 sm_sc_prepare_dhkey_check(sm_conn); 1392 } 1393 break; 1394 case OOB: 1395 sm_sc_prepare_dhkey_check(sm_conn); 1396 break; 1397 } 1398 } 1399 } 1400 1401 static void sm_sc_cmac_done(uint8_t * hash){ 1402 log_info("sm_sc_cmac_done: "); 1403 log_info_hexdump(hash, 16); 1404 1405 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1406 sm_sc_oob_state = SM_SC_OOB_IDLE; 1407 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1408 return; 1409 } 1410 1411 sm_connection_t * sm_conn = sm_cmac_connection; 1412 sm_cmac_connection = NULL; 1413 #ifdef ENABLE_CLASSIC 1414 link_key_type_t link_key_type; 1415 #endif 1416 1417 switch (sm_conn->sm_engine_state){ 1418 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1419 memcpy(setup->sm_local_confirm, hash, 16); 1420 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1421 break; 1422 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1423 // check 1424 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1425 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1426 break; 1427 } 1428 sm_sc_state_after_receiving_random(sm_conn); 1429 break; 1430 case SM_SC_W4_CALCULATE_G2: { 1431 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1432 big_endian_store_32(setup->sm_tk, 12, vab); 1433 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1434 sm_trigger_user_response(sm_conn); 1435 break; 1436 } 1437 case SM_SC_W4_CALCULATE_F5_SALT: 1438 memcpy(setup->sm_t, hash, 16); 1439 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1440 break; 1441 case SM_SC_W4_CALCULATE_F5_MACKEY: 1442 memcpy(setup->sm_mackey, hash, 16); 1443 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1444 break; 1445 case SM_SC_W4_CALCULATE_F5_LTK: 1446 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1447 // Errata Service Release to the Bluetooth Specification: ESR09 1448 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1449 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1450 memcpy(setup->sm_ltk, hash, 16); 1451 memcpy(setup->sm_local_ltk, hash, 16); 1452 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1453 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1454 break; 1455 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1456 memcpy(setup->sm_local_dhkey_check, hash, 16); 1457 if (IS_RESPONDER(sm_conn->sm_role)){ 1458 // responder 1459 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1460 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1461 } else { 1462 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1463 } 1464 } else { 1465 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1466 } 1467 break; 1468 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1469 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1470 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1471 break; 1472 } 1473 if (IS_RESPONDER(sm_conn->sm_role)){ 1474 // responder 1475 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1476 } else { 1477 // initiator 1478 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1479 } 1480 break; 1481 case SM_SC_W4_CALCULATE_H6_ILK: 1482 memcpy(setup->sm_t, hash, 16); 1483 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1484 break; 1485 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1486 #ifdef ENABLE_CLASSIC 1487 reverse_128(hash, setup->sm_t); 1488 link_key_type = sm_conn->sm_connection_authenticated ? 1489 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1490 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1491 if (IS_RESPONDER(sm_conn->sm_role)){ 1492 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1493 } else { 1494 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1495 } 1496 #endif 1497 if (IS_RESPONDER(sm_conn->sm_role)){ 1498 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1499 } else { 1500 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1501 } 1502 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1503 sm_done_for_handle(sm_conn->sm_handle); 1504 break; 1505 default: 1506 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1507 break; 1508 } 1509 sm_run(); 1510 } 1511 1512 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){ 1513 const uint16_t message_len = 65; 1514 sm_cmac_connection = sm_conn; 1515 memcpy(sm_cmac_sc_buffer, u, 32); 1516 memcpy(sm_cmac_sc_buffer+32, v, 32); 1517 sm_cmac_sc_buffer[64] = z; 1518 log_info("f4 key"); 1519 log_info_hexdump(x, 16); 1520 log_info("f4 message"); 1521 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1522 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1523 } 1524 1525 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1526 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1527 static const uint8_t f5_length[] = { 0x01, 0x00}; 1528 1529 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1530 log_info("f5_calculate_salt"); 1531 // calculate salt for f5 1532 const uint16_t message_len = 32; 1533 sm_cmac_connection = sm_conn; 1534 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1535 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1536 } 1537 1538 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){ 1539 const uint16_t message_len = 53; 1540 sm_cmac_connection = sm_conn; 1541 1542 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1543 sm_cmac_sc_buffer[0] = 0; 1544 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1545 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1546 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1547 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1548 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1549 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1550 log_info("f5 key"); 1551 log_info_hexdump(t, 16); 1552 log_info("f5 message for MacKey"); 1553 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1554 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1555 } 1556 1557 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1558 sm_key56_t bd_addr_master, bd_addr_slave; 1559 bd_addr_master[0] = setup->sm_m_addr_type; 1560 bd_addr_slave[0] = setup->sm_s_addr_type; 1561 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1562 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1563 if (IS_RESPONDER(sm_conn->sm_role)){ 1564 // responder 1565 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1566 } else { 1567 // initiator 1568 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1569 } 1570 } 1571 1572 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1573 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1574 const uint16_t message_len = 53; 1575 sm_cmac_connection = sm_conn; 1576 sm_cmac_sc_buffer[0] = 1; 1577 // 1..52 setup before 1578 log_info("f5 key"); 1579 log_info_hexdump(t, 16); 1580 log_info("f5 message for LTK"); 1581 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1582 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1583 } 1584 1585 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1586 f5_ltk(sm_conn, setup->sm_t); 1587 } 1588 1589 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){ 1590 const uint16_t message_len = 65; 1591 sm_cmac_connection = sm_conn; 1592 memcpy(sm_cmac_sc_buffer, n1, 16); 1593 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1594 memcpy(sm_cmac_sc_buffer+32, r, 16); 1595 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1596 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1597 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1598 log_info("f6 key"); 1599 log_info_hexdump(w, 16); 1600 log_info("f6 message"); 1601 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1602 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1603 } 1604 1605 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1606 // - U is 256 bits 1607 // - V is 256 bits 1608 // - X is 128 bits 1609 // - Y is 128 bits 1610 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){ 1611 const uint16_t message_len = 80; 1612 sm_cmac_connection = sm_conn; 1613 memcpy(sm_cmac_sc_buffer, u, 32); 1614 memcpy(sm_cmac_sc_buffer+32, v, 32); 1615 memcpy(sm_cmac_sc_buffer+64, y, 16); 1616 log_info("g2 key"); 1617 log_info_hexdump(x, 16); 1618 log_info("g2 message"); 1619 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1620 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1621 } 1622 1623 static void g2_calculate(sm_connection_t * sm_conn) { 1624 // calc Va if numeric comparison 1625 if (IS_RESPONDER(sm_conn->sm_role)){ 1626 // responder 1627 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1628 } else { 1629 // initiator 1630 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1631 } 1632 } 1633 1634 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1635 uint8_t z = 0; 1636 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1637 // some form of passkey 1638 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1639 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1640 setup->sm_passkey_bit++; 1641 } 1642 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1643 } 1644 1645 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1646 // OOB 1647 if (setup->sm_stk_generation_method == OOB){ 1648 if (IS_RESPONDER(sm_conn->sm_role)){ 1649 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1650 } else { 1651 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1652 } 1653 return; 1654 } 1655 1656 uint8_t z = 0; 1657 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1658 // some form of passkey 1659 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1660 // sm_passkey_bit was increased before sending confirm value 1661 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1662 } 1663 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1664 } 1665 1666 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1667 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1668 1669 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1670 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1671 return; 1672 } else { 1673 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1674 } 1675 } 1676 1677 static void sm_sc_dhkey_calculated(void * arg){ 1678 sm_connection_t * sm_conn = (sm_connection_t *) arg; 1679 log_info("dhkey"); 1680 log_info_hexdump(&setup->sm_dhkey[0], 32); 1681 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1682 // trigger next step 1683 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1684 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1685 } 1686 sm_run(); 1687 } 1688 1689 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1690 // calculate DHKCheck 1691 sm_key56_t bd_addr_master, bd_addr_slave; 1692 bd_addr_master[0] = setup->sm_m_addr_type; 1693 bd_addr_slave[0] = setup->sm_s_addr_type; 1694 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1695 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1696 uint8_t iocap_a[3]; 1697 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1698 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1699 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1700 uint8_t iocap_b[3]; 1701 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1702 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1703 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1704 if (IS_RESPONDER(sm_conn->sm_role)){ 1705 // responder 1706 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); 1707 } else { 1708 // initiator 1709 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); 1710 } 1711 } 1712 1713 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1714 // validate E = f6() 1715 sm_key56_t bd_addr_master, bd_addr_slave; 1716 bd_addr_master[0] = setup->sm_m_addr_type; 1717 bd_addr_slave[0] = setup->sm_s_addr_type; 1718 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1719 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1720 1721 uint8_t iocap_a[3]; 1722 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1723 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1724 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1725 uint8_t iocap_b[3]; 1726 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1727 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1728 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1729 if (IS_RESPONDER(sm_conn->sm_role)){ 1730 // responder 1731 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); 1732 } else { 1733 // initiator 1734 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); 1735 } 1736 } 1737 1738 1739 // 1740 // Link Key Conversion Function h6 1741 // 1742 // h6(W, keyID) = AES-CMACW(keyID) 1743 // - W is 128 bits 1744 // - keyID is 32 bits 1745 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1746 const uint16_t message_len = 4; 1747 sm_cmac_connection = sm_conn; 1748 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1749 log_info("h6 key"); 1750 log_info_hexdump(w, 16); 1751 log_info("h6 message"); 1752 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1753 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1754 } 1755 1756 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1757 // Errata Service Release to the Bluetooth Specification: ESR09 1758 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1759 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1760 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1761 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1762 } 1763 1764 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1765 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1766 } 1767 1768 #endif 1769 1770 // key management legacy connections: 1771 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1772 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1773 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1774 // - responder reconnects: responder uses LTK receveived from master 1775 1776 // key management secure connections: 1777 // - both devices store same LTK from ECDH key exchange. 1778 1779 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1780 static void sm_load_security_info(sm_connection_t * sm_connection){ 1781 int encryption_key_size; 1782 int authenticated; 1783 int authorized; 1784 1785 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1786 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1787 &encryption_key_size, &authenticated, &authorized); 1788 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1789 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1790 sm_connection->sm_connection_authenticated = authenticated; 1791 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1792 } 1793 #endif 1794 1795 #ifdef ENABLE_LE_PERIPHERAL 1796 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1797 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1798 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1799 // re-establish used key encryption size 1800 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1801 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1802 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1803 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1804 log_info("sm: received ltk request with key size %u, authenticated %u", 1805 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1806 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1807 sm_run(); 1808 } 1809 #endif 1810 1811 static void sm_run(void){ 1812 1813 btstack_linked_list_iterator_t it; 1814 1815 // assert that stack has already bootet 1816 if (hci_get_state() != HCI_STATE_WORKING) return; 1817 1818 // assert that we can send at least commands 1819 if (!hci_can_send_command_packet_now()) return; 1820 1821 // pause until IR/ER are ready 1822 if (sm_persistent_keys_random_active) return; 1823 1824 // 1825 // non-connection related behaviour 1826 // 1827 1828 // distributed key generation 1829 switch (dkg_state){ 1830 case DKG_CALC_IRK: 1831 // already busy? 1832 if (sm_aes128_state == SM_AES128_IDLE) { 1833 log_info("DKG_CALC_IRK started"); 1834 // IRK = d1(IR, 1, 0) 1835 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1836 sm_aes128_state = SM_AES128_ACTIVE; 1837 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1838 return; 1839 } 1840 break; 1841 case DKG_CALC_DHK: 1842 // already busy? 1843 if (sm_aes128_state == SM_AES128_IDLE) { 1844 log_info("DKG_CALC_DHK started"); 1845 // DHK = d1(IR, 3, 0) 1846 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1847 sm_aes128_state = SM_AES128_ACTIVE; 1848 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1849 return; 1850 } 1851 break; 1852 default: 1853 break; 1854 } 1855 1856 // random address updates 1857 switch (rau_state){ 1858 case RAU_GET_RANDOM: 1859 rau_state = RAU_W4_RANDOM; 1860 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1861 return; 1862 case RAU_GET_ENC: 1863 // already busy? 1864 if (sm_aes128_state == SM_AES128_IDLE) { 1865 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1866 sm_aes128_state = SM_AES128_ACTIVE; 1867 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1868 return; 1869 } 1870 break; 1871 case RAU_SET_ADDRESS: 1872 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1873 rau_state = RAU_IDLE; 1874 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1875 return; 1876 default: 1877 break; 1878 } 1879 1880 // CSRK Lookup 1881 // -- if csrk lookup ready, find connection that require csrk lookup 1882 if (sm_address_resolution_idle()){ 1883 hci_connections_get_iterator(&it); 1884 while(btstack_linked_list_iterator_has_next(&it)){ 1885 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1886 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1887 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1888 // and start lookup 1889 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); 1890 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1891 break; 1892 } 1893 } 1894 } 1895 1896 // -- if csrk lookup ready, resolved addresses for received addresses 1897 if (sm_address_resolution_idle()) { 1898 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1899 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1900 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1901 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1902 btstack_memory_sm_lookup_entry_free(entry); 1903 } 1904 } 1905 1906 // -- Continue with CSRK device lookup by public or resolvable private address 1907 if (!sm_address_resolution_idle()){ 1908 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1909 while (sm_address_resolution_test < le_device_db_max_count()){ 1910 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1911 bd_addr_t addr; 1912 sm_key_t irk; 1913 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1914 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1915 1916 // skip unused entries 1917 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1918 sm_address_resolution_test++; 1919 continue; 1920 } 1921 1922 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1923 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1924 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1925 break; 1926 } 1927 1928 // if entry is public address, it is for a different device 1929 if (addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1930 sm_address_resolution_test++; 1931 continue; 1932 } 1933 1934 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1935 1936 log_info("LE Device Lookup: calculate AH"); 1937 log_info_key("IRK", irk); 1938 1939 memcpy(sm_aes128_key, irk, 16); 1940 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1941 sm_address_resolution_ah_calculation_active = 1; 1942 sm_aes128_state = SM_AES128_ACTIVE; 1943 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1944 return; 1945 } 1946 1947 if (sm_address_resolution_test >= le_device_db_max_count()){ 1948 log_info("LE Device Lookup: not found"); 1949 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1950 } 1951 } 1952 1953 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1954 switch (sm_sc_oob_state){ 1955 case SM_SC_OOB_W2_CALC_CONFIRM: 1956 if (!sm_cmac_ready()) break; 1957 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1958 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1959 return; 1960 default: 1961 break; 1962 } 1963 #endif 1964 1965 // assert that we can send at least commands - cmd might have been sent by crypto engine 1966 if (!hci_can_send_command_packet_now()) return; 1967 1968 // handle basic actions that don't requires the full context 1969 hci_connections_get_iterator(&it); 1970 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1971 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1972 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1973 switch(sm_connection->sm_engine_state){ 1974 // responder side 1975 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1976 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1977 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1978 return; 1979 1980 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1981 case SM_SC_RECEIVED_LTK_REQUEST: 1982 switch (sm_connection->sm_irk_lookup_state){ 1983 case IRK_LOOKUP_FAILED: 1984 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1985 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1986 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1987 return; 1988 default: 1989 break; 1990 } 1991 break; 1992 #endif 1993 default: 1994 break; 1995 } 1996 } 1997 1998 // 1999 // active connection handling 2000 // -- use loop to handle next connection if lock on setup context is released 2001 2002 while (1) { 2003 2004 // Find connections that requires setup context and make active if no other is locked 2005 hci_connections_get_iterator(&it); 2006 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2007 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2008 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2009 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2010 int done = 1; 2011 int err; 2012 UNUSED(err); 2013 2014 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2015 // assert ec key is ready 2016 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2017 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2018 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2019 sm_ec_generate_new_key(); 2020 } 2021 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2022 continue; 2023 } 2024 } 2025 #endif 2026 2027 switch (sm_connection->sm_engine_state) { 2028 #ifdef ENABLE_LE_PERIPHERAL 2029 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2030 // send packet if possible, 2031 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2032 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2033 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2034 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2035 } else { 2036 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2037 } 2038 // don't lock sxetup context yet 2039 done = 0; 2040 break; 2041 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2042 sm_reset_setup(); 2043 sm_init_setup(sm_connection); 2044 // recover pairing request 2045 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2046 err = sm_stk_generation_init(sm_connection); 2047 2048 #ifdef ENABLE_TESTING_SUPPORT 2049 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2050 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2051 err = test_pairing_failure; 2052 } 2053 #endif 2054 if (err){ 2055 setup->sm_pairing_failed_reason = err; 2056 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2057 break; 2058 } 2059 sm_timeout_start(sm_connection); 2060 // generate random number first, if we need to show passkey 2061 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2062 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2063 break; 2064 } 2065 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2066 break; 2067 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2068 sm_reset_setup(); 2069 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2070 break; 2071 2072 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2073 case SM_SC_RECEIVED_LTK_REQUEST: 2074 switch (sm_connection->sm_irk_lookup_state){ 2075 case IRK_LOOKUP_SUCCEEDED: 2076 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2077 // start using context by loading security info 2078 sm_reset_setup(); 2079 sm_load_security_info(sm_connection); 2080 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2081 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2082 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2083 break; 2084 } 2085 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2086 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2087 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2088 // don't lock setup context yet 2089 return; 2090 default: 2091 // just wait until IRK lookup is completed 2092 // don't lock setup context yet 2093 done = 0; 2094 break; 2095 } 2096 break; 2097 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2098 #endif /* ENABLE_LE_PERIPHERAL */ 2099 2100 #ifdef ENABLE_LE_CENTRAL 2101 case SM_INITIATOR_PH0_HAS_LTK: 2102 sm_reset_setup(); 2103 sm_load_security_info(sm_connection); 2104 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2105 break; 2106 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2107 sm_reset_setup(); 2108 sm_init_setup(sm_connection); 2109 sm_timeout_start(sm_connection); 2110 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2111 break; 2112 #endif 2113 2114 default: 2115 done = 0; 2116 break; 2117 } 2118 if (done){ 2119 sm_active_connection_handle = sm_connection->sm_handle; 2120 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); 2121 } 2122 } 2123 2124 // 2125 // active connection handling 2126 // 2127 2128 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2129 2130 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2131 if (!connection) { 2132 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2133 return; 2134 } 2135 2136 // assert that we could send a SM PDU - not needed for all of the following 2137 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2138 log_info("cannot send now, requesting can send now event"); 2139 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2140 return; 2141 } 2142 2143 // send keypress notifications 2144 if (setup->sm_keypress_notification){ 2145 int i; 2146 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2147 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2148 uint8_t action = 0; 2149 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2150 if (flags & (1<<i)){ 2151 int clear_flag = 1; 2152 switch (i){ 2153 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2154 case SM_KEYPRESS_PASSKEY_CLEARED: 2155 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2156 default: 2157 break; 2158 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2159 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2160 num_actions--; 2161 clear_flag = num_actions == 0; 2162 break; 2163 } 2164 if (clear_flag){ 2165 flags &= ~(1<<i); 2166 } 2167 action = i; 2168 break; 2169 } 2170 } 2171 setup->sm_keypress_notification = (num_actions << 5) | flags; 2172 2173 // send keypress notification 2174 uint8_t buffer[2]; 2175 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2176 buffer[1] = action; 2177 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2178 2179 // try 2180 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2181 return; 2182 } 2183 2184 int key_distribution_flags; 2185 UNUSED(key_distribution_flags); 2186 2187 log_info("sm_run: state %u", connection->sm_engine_state); 2188 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2189 log_info("sm_run // cannot send"); 2190 } 2191 switch (connection->sm_engine_state){ 2192 2193 // general 2194 case SM_GENERAL_SEND_PAIRING_FAILED: { 2195 uint8_t buffer[2]; 2196 buffer[0] = SM_CODE_PAIRING_FAILED; 2197 buffer[1] = setup->sm_pairing_failed_reason; 2198 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2199 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2200 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2201 sm_done_for_handle(connection->sm_handle); 2202 break; 2203 } 2204 2205 // responding state 2206 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2207 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2208 if (!sm_cmac_ready()) break; 2209 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2210 sm_sc_calculate_local_confirm(connection); 2211 break; 2212 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2213 if (!sm_cmac_ready()) break; 2214 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2215 sm_sc_calculate_remote_confirm(connection); 2216 break; 2217 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2218 if (!sm_cmac_ready()) break; 2219 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2220 sm_sc_calculate_f6_for_dhkey_check(connection); 2221 break; 2222 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2223 if (!sm_cmac_ready()) break; 2224 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2225 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2226 break; 2227 case SM_SC_W2_CALCULATE_F5_SALT: 2228 if (!sm_cmac_ready()) break; 2229 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2230 f5_calculate_salt(connection); 2231 break; 2232 case SM_SC_W2_CALCULATE_F5_MACKEY: 2233 if (!sm_cmac_ready()) break; 2234 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2235 f5_calculate_mackey(connection); 2236 break; 2237 case SM_SC_W2_CALCULATE_F5_LTK: 2238 if (!sm_cmac_ready()) break; 2239 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2240 f5_calculate_ltk(connection); 2241 break; 2242 case SM_SC_W2_CALCULATE_G2: 2243 if (!sm_cmac_ready()) break; 2244 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2245 g2_calculate(connection); 2246 break; 2247 case SM_SC_W2_CALCULATE_H6_ILK: 2248 if (!sm_cmac_ready()) break; 2249 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2250 h6_calculate_ilk(connection); 2251 break; 2252 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2253 if (!sm_cmac_ready()) break; 2254 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2255 h6_calculate_br_edr_link_key(connection); 2256 break; 2257 #endif 2258 2259 #ifdef ENABLE_LE_CENTRAL 2260 // initiator side 2261 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2262 sm_key_t peer_ltk_flipped; 2263 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2264 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2265 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2266 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2267 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2268 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2269 return; 2270 } 2271 2272 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2273 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2274 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2275 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2276 sm_timeout_reset(connection); 2277 break; 2278 #endif 2279 2280 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2281 2282 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2283 int trigger_user_response = 0; 2284 2285 uint8_t buffer[65]; 2286 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2287 // 2288 reverse_256(&ec_q[0], &buffer[1]); 2289 reverse_256(&ec_q[32], &buffer[33]); 2290 2291 #ifdef ENABLE_TESTING_SUPPORT 2292 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2293 log_info("testing_support: invalidating public key"); 2294 // flip single bit of public key coordinate 2295 buffer[1] ^= 1; 2296 } 2297 #endif 2298 2299 // stk generation method 2300 // passkey entry: notify app to show passkey or to request passkey 2301 switch (setup->sm_stk_generation_method){ 2302 case JUST_WORKS: 2303 case NUMERIC_COMPARISON: 2304 if (IS_RESPONDER(connection->sm_role)){ 2305 // responder 2306 sm_sc_start_calculating_local_confirm(connection); 2307 } else { 2308 // initiator 2309 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2310 } 2311 break; 2312 case PK_INIT_INPUT: 2313 case PK_RESP_INPUT: 2314 case PK_BOTH_INPUT: 2315 // use random TK for display 2316 memcpy(setup->sm_ra, setup->sm_tk, 16); 2317 memcpy(setup->sm_rb, setup->sm_tk, 16); 2318 setup->sm_passkey_bit = 0; 2319 2320 if (IS_RESPONDER(connection->sm_role)){ 2321 // responder 2322 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2323 } else { 2324 // initiator 2325 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2326 } 2327 trigger_user_response = 1; 2328 break; 2329 case OOB: 2330 if (IS_RESPONDER(connection->sm_role)){ 2331 // responder 2332 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2333 } else { 2334 // initiator 2335 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2336 } 2337 break; 2338 } 2339 2340 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2341 sm_timeout_reset(connection); 2342 2343 // trigger user response after sending pdu 2344 if (trigger_user_response){ 2345 sm_trigger_user_response(connection); 2346 } 2347 break; 2348 } 2349 case SM_SC_SEND_CONFIRMATION: { 2350 uint8_t buffer[17]; 2351 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2352 reverse_128(setup->sm_local_confirm, &buffer[1]); 2353 if (IS_RESPONDER(connection->sm_role)){ 2354 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2355 } else { 2356 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2357 } 2358 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2359 sm_timeout_reset(connection); 2360 break; 2361 } 2362 case SM_SC_SEND_PAIRING_RANDOM: { 2363 uint8_t buffer[17]; 2364 buffer[0] = SM_CODE_PAIRING_RANDOM; 2365 reverse_128(setup->sm_local_nonce, &buffer[1]); 2366 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2367 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2368 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2369 if (IS_RESPONDER(connection->sm_role)){ 2370 // responder 2371 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2372 } else { 2373 // initiator 2374 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2375 } 2376 } else { 2377 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2378 if (IS_RESPONDER(connection->sm_role)){ 2379 // responder 2380 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2381 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2382 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2383 } else { 2384 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2385 sm_sc_prepare_dhkey_check(connection); 2386 } 2387 } else { 2388 // initiator 2389 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2390 } 2391 } 2392 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2393 sm_timeout_reset(connection); 2394 break; 2395 } 2396 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2397 uint8_t buffer[17]; 2398 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2399 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2400 2401 if (IS_RESPONDER(connection->sm_role)){ 2402 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2403 } else { 2404 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2405 } 2406 2407 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2408 sm_timeout_reset(connection); 2409 break; 2410 } 2411 2412 #endif 2413 2414 #ifdef ENABLE_LE_PERIPHERAL 2415 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2416 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2417 2418 // start with initiator key dist flags 2419 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2420 2421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2422 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2423 if (setup->sm_use_secure_connections){ 2424 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2425 } 2426 #endif 2427 // setup in response 2428 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); 2429 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); 2430 2431 // update key distribution after ENC was dropped 2432 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2433 2434 if (setup->sm_use_secure_connections){ 2435 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2436 } else { 2437 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2438 } 2439 2440 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2441 sm_timeout_reset(connection); 2442 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2443 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2444 sm_trigger_user_response(connection); 2445 } 2446 return; 2447 #endif 2448 2449 case SM_PH2_SEND_PAIRING_RANDOM: { 2450 uint8_t buffer[17]; 2451 buffer[0] = SM_CODE_PAIRING_RANDOM; 2452 reverse_128(setup->sm_local_random, &buffer[1]); 2453 if (IS_RESPONDER(connection->sm_role)){ 2454 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2455 } else { 2456 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2457 } 2458 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2459 sm_timeout_reset(connection); 2460 break; 2461 } 2462 2463 case SM_PH2_C1_GET_ENC_A: 2464 // already busy? 2465 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2466 // calculate confirm using aes128 engine - step 1 2467 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, sm_aes128_plaintext); 2468 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2469 sm_aes128_state = SM_AES128_ACTIVE; 2470 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2471 break; 2472 2473 case SM_PH2_C1_GET_ENC_C: 2474 // already busy? 2475 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2476 // calculate m_confirm using aes128 engine - step 1 2477 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, sm_aes128_plaintext); 2478 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2479 sm_aes128_state = SM_AES128_ACTIVE; 2480 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2481 break; 2482 2483 case SM_PH2_CALC_STK: 2484 // already busy? 2485 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2486 // calculate STK 2487 if (IS_RESPONDER(connection->sm_role)){ 2488 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2489 } else { 2490 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2491 } 2492 connection->sm_engine_state = SM_PH2_W4_STK; 2493 sm_aes128_state = SM_AES128_ACTIVE; 2494 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2495 break; 2496 2497 case SM_PH3_Y_GET_ENC: 2498 // already busy? 2499 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2500 // PH3B2 - calculate Y from - enc 2501 // Y = dm(DHK, Rand) 2502 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2503 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2504 sm_aes128_state = SM_AES128_ACTIVE; 2505 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, connection); 2506 break; 2507 2508 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2509 uint8_t buffer[17]; 2510 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2511 reverse_128(setup->sm_local_confirm, &buffer[1]); 2512 if (IS_RESPONDER(connection->sm_role)){ 2513 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2514 } else { 2515 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2516 } 2517 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2518 sm_timeout_reset(connection); 2519 return; 2520 } 2521 #ifdef ENABLE_LE_PERIPHERAL 2522 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2523 sm_key_t stk_flipped; 2524 reverse_128(setup->sm_ltk, stk_flipped); 2525 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2526 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2527 return; 2528 } 2529 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2530 sm_key_t ltk_flipped; 2531 reverse_128(setup->sm_ltk, ltk_flipped); 2532 connection->sm_engine_state = SM_RESPONDER_IDLE; 2533 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2534 sm_done_for_handle(connection->sm_handle); 2535 return; 2536 } 2537 case SM_RESPONDER_PH4_Y_GET_ENC: 2538 // already busy? 2539 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2540 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2541 // Y = dm(DHK, Rand) 2542 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2543 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2544 sm_aes128_state = SM_AES128_ACTIVE; 2545 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, connection); 2546 return; 2547 #endif 2548 #ifdef ENABLE_LE_CENTRAL 2549 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2550 sm_key_t stk_flipped; 2551 reverse_128(setup->sm_ltk, stk_flipped); 2552 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2553 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2554 return; 2555 } 2556 #endif 2557 2558 case SM_PH3_DISTRIBUTE_KEYS: 2559 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2560 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2561 uint8_t buffer[17]; 2562 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2563 reverse_128(setup->sm_ltk, &buffer[1]); 2564 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2565 sm_timeout_reset(connection); 2566 return; 2567 } 2568 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2569 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2570 uint8_t buffer[11]; 2571 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2572 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2573 reverse_64(setup->sm_local_rand, &buffer[3]); 2574 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2575 sm_timeout_reset(connection); 2576 return; 2577 } 2578 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2579 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2580 uint8_t buffer[17]; 2581 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2582 reverse_128(sm_persistent_irk, &buffer[1]); 2583 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2584 sm_timeout_reset(connection); 2585 return; 2586 } 2587 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2588 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2589 bd_addr_t local_address; 2590 uint8_t buffer[8]; 2591 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2592 switch (gap_random_address_get_mode()){ 2593 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2594 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2595 // public or static random 2596 gap_le_get_own_address(&buffer[1], local_address); 2597 break; 2598 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2599 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2600 // fallback to public 2601 gap_local_bd_addr(local_address); 2602 buffer[1] = 0; 2603 break; 2604 } 2605 reverse_bd_addr(local_address, &buffer[2]); 2606 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2607 sm_timeout_reset(connection); 2608 return; 2609 } 2610 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2611 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2612 2613 // hack to reproduce test runs 2614 if (test_use_fixed_local_csrk){ 2615 memset(setup->sm_local_csrk, 0xcc, 16); 2616 } 2617 2618 uint8_t buffer[17]; 2619 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2620 reverse_128(setup->sm_local_csrk, &buffer[1]); 2621 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2622 sm_timeout_reset(connection); 2623 return; 2624 } 2625 2626 // keys are sent 2627 if (IS_RESPONDER(connection->sm_role)){ 2628 // slave -> receive master keys if any 2629 if (sm_key_distribution_all_received(connection)){ 2630 sm_key_distribution_handle_all_received(connection); 2631 connection->sm_engine_state = SM_RESPONDER_IDLE; 2632 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2633 sm_done_for_handle(connection->sm_handle); 2634 } else { 2635 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2636 } 2637 } else { 2638 // master -> all done 2639 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2640 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2641 sm_done_for_handle(connection->sm_handle); 2642 } 2643 break; 2644 2645 default: 2646 break; 2647 } 2648 2649 // check again if active connection was released 2650 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2651 } 2652 } 2653 2654 // sm_aes128_state stays active 2655 static void sm_handle_encryption_result_enc_a(void *arg){ 2656 sm_connection_t * connection = (sm_connection_t*) arg; 2657 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2658 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, connection); 2659 } 2660 2661 static void sm_handle_encryption_result_enc_b(void *arg){ 2662 sm_connection_t * connection = (sm_connection_t*) arg; 2663 sm_aes128_state = SM_AES128_IDLE; 2664 log_info_key("c1!", setup->sm_local_confirm); 2665 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2666 sm_run(); 2667 } 2668 2669 // sm_aes128_state stays active 2670 static void sm_handle_encryption_result_enc_c(void *arg){ 2671 sm_connection_t * connection = (sm_connection_t*) arg; 2672 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2673 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, connection); 2674 } 2675 2676 static void sm_handle_encryption_result_enc_d(void * arg){ 2677 sm_connection_t * connection = (sm_connection_t*) arg; 2678 sm_aes128_state = SM_AES128_IDLE; 2679 log_info_key("c1!", sm_aes128_ciphertext); 2680 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2681 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2682 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2683 sm_run(); 2684 return; 2685 } 2686 if (IS_RESPONDER(connection->sm_role)){ 2687 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2688 sm_run(); 2689 } else { 2690 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2691 sm_aes128_state = SM_AES128_ACTIVE; 2692 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2693 } 2694 } 2695 2696 static void sm_handle_encryption_result_enc_stk(void *arg){ 2697 sm_connection_t * connection = (sm_connection_t*) arg; 2698 sm_aes128_state = SM_AES128_IDLE; 2699 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2700 log_info_key("stk", setup->sm_ltk); 2701 if (IS_RESPONDER(connection->sm_role)){ 2702 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2703 } else { 2704 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2705 } 2706 sm_run(); 2707 } 2708 2709 // sm_aes128_state stays active 2710 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2711 sm_connection_t * connection = (sm_connection_t*) arg; 2712 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2713 log_info_hex16("y", setup->sm_local_y); 2714 // PH3B3 - calculate EDIV 2715 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2716 log_info_hex16("ediv", setup->sm_local_ediv); 2717 // PH3B4 - calculate LTK - enc 2718 // LTK = d1(ER, DIV, 0)) 2719 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2720 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, connection); 2721 } 2722 2723 #ifdef ENABLE_LE_PERIPHERAL 2724 // sm_aes128_state stays active 2725 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2726 sm_connection_t * connection = (sm_connection_t*) arg; 2727 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2728 log_info_hex16("y", setup->sm_local_y); 2729 2730 // PH3B3 - calculate DIV 2731 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2732 log_info_hex16("ediv", setup->sm_local_ediv); 2733 // PH3B4 - calculate LTK - enc 2734 // LTK = d1(ER, DIV, 0)) 2735 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2736 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, connection); 2737 } 2738 #endif 2739 2740 // sm_aes128_state stays active 2741 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2742 sm_connection_t * connection = (sm_connection_t*) arg; 2743 log_info_key("ltk", setup->sm_ltk); 2744 // calc CSRK next 2745 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2746 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, connection); 2747 } 2748 2749 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2750 sm_connection_t * connection = (sm_connection_t*) arg; 2751 sm_aes128_state = SM_AES128_IDLE; 2752 log_info_key("csrk", setup->sm_local_csrk); 2753 if (setup->sm_key_distribution_send_set){ 2754 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2755 } else { 2756 // no keys to send, just continue 2757 if (IS_RESPONDER(connection->sm_role)){ 2758 // slave -> receive master keys 2759 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2760 } else { 2761 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2762 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2763 } else { 2764 // master -> all done 2765 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2766 sm_done_for_handle(connection->sm_handle); 2767 } 2768 } 2769 } 2770 sm_run(); 2771 } 2772 2773 #ifdef ENABLE_LE_PERIPHERAL 2774 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2775 sm_connection_t * connection = (sm_connection_t*) arg; 2776 sm_aes128_state = SM_AES128_IDLE; 2777 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2778 log_info_key("ltk", setup->sm_ltk); 2779 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2780 sm_run(); 2781 } 2782 #endif 2783 2784 static void sm_handle_encryption_result_address_resolution(void *arg){ 2785 UNUSED(arg); 2786 sm_aes128_state = SM_AES128_IDLE; 2787 sm_address_resolution_ah_calculation_active = 0; 2788 // compare calulated address against connecting device 2789 uint8_t * hash = &sm_aes128_ciphertext[13]; 2790 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2791 log_info("LE Device Lookup: matched resolvable private address"); 2792 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2793 sm_run(); 2794 return; 2795 } 2796 // no match, try next 2797 sm_address_resolution_test++; 2798 sm_run(); 2799 } 2800 2801 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2802 UNUSED(arg); 2803 sm_aes128_state = SM_AES128_IDLE; 2804 log_info_key("irk", sm_persistent_irk); 2805 dkg_state = DKG_CALC_DHK; 2806 sm_run(); 2807 } 2808 2809 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2810 UNUSED(arg); 2811 sm_aes128_state = SM_AES128_IDLE; 2812 log_info_key("dhk", sm_persistent_dhk); 2813 dkg_state = DKG_READY; 2814 sm_run(); 2815 } 2816 2817 static void sm_handle_encryption_result_rau(void *arg){ 2818 UNUSED(arg); 2819 sm_aes128_state = SM_AES128_IDLE; 2820 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2821 rau_state = RAU_SET_ADDRESS; 2822 sm_run(); 2823 } 2824 2825 static void sm_handle_random_result_rau(void * arg){ 2826 UNUSED(arg); 2827 // non-resolvable vs. resolvable 2828 switch (gap_random_adress_type){ 2829 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2830 // resolvable: use random as prand and calc address hash 2831 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2832 sm_random_address[0] &= 0x3f; 2833 sm_random_address[0] |= 0x40; 2834 rau_state = RAU_GET_ENC; 2835 break; 2836 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2837 default: 2838 // "The two most significant bits of the address shall be equal to ‘0’"" 2839 sm_random_address[0] &= 0x3f; 2840 rau_state = RAU_SET_ADDRESS; 2841 break; 2842 } 2843 sm_run(); 2844 } 2845 2846 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2847 static void sm_handle_random_result_sc_get_random(void * arg){ 2848 sm_connection_t * connection = (sm_connection_t*) arg; 2849 2850 // OOB 2851 if (setup->sm_stk_generation_method == OOB){ 2852 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2853 sm_run(); 2854 return; 2855 } 2856 2857 // initiator & jw/nc -> send pairing random 2858 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2859 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2860 } else { 2861 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2862 } 2863 sm_run(); 2864 } 2865 #endif 2866 2867 static void sm_handle_random_result_ph2_random(void * arg){ 2868 sm_connection_t * connection = (sm_connection_t*) arg; 2869 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2870 sm_run(); 2871 } 2872 2873 static void sm_handle_random_result_ph2_tk(void * arg){ 2874 sm_connection_t * connection = (sm_connection_t*) arg; 2875 sm_reset_tk(); 2876 uint32_t tk; 2877 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2878 // map random to 0-999999 without speding much cycles on a modulus operation 2879 tk = little_endian_read_32(sm_random_data,0); 2880 tk = tk & 0xfffff; // 1048575 2881 if (tk >= 999999){ 2882 tk = tk - 999999; 2883 } 2884 } else { 2885 // override with pre-defined passkey 2886 tk = sm_fixed_passkey_in_display_role; 2887 } 2888 big_endian_store_32(setup->sm_tk, 12, tk); 2889 if (IS_RESPONDER(connection->sm_role)){ 2890 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2891 } else { 2892 if (setup->sm_use_secure_connections){ 2893 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2894 } else { 2895 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2896 sm_trigger_user_response(connection); 2897 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2898 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2899 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2900 } 2901 } 2902 } 2903 sm_run(); 2904 } 2905 2906 static void sm_handle_random_result_ph3_div(void * arg){ 2907 sm_connection_t * connection = (sm_connection_t*) arg; 2908 // use 16 bit from random value as div 2909 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2910 log_info_hex16("div", setup->sm_local_div); 2911 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2912 sm_run(); 2913 } 2914 2915 static void sm_handle_random_result_ph3_random(void * arg){ 2916 sm_connection_t * connection = (sm_connection_t*) arg; 2917 reverse_64(sm_random_data, setup->sm_local_rand); 2918 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2919 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2920 // no db for authenticated flag hack: store flag in bit 4 of LSB 2921 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2922 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2923 } 2924 static void sm_validate_er_ir(void){ 2925 // warn about default ER/IR 2926 int warning = 0; 2927 if (sm_ir_is_default()){ 2928 warning = 1; 2929 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 2930 } 2931 if (sm_er_is_default()){ 2932 warning = 1; 2933 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 2934 } 2935 if (warning) { 2936 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 2937 } 2938 } 2939 2940 static void sm_handle_random_result_ir(void *arg){ 2941 sm_persistent_keys_random_active = 0; 2942 if (arg){ 2943 // key generated, store in tlv 2944 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2945 log_info("Generated IR key. Store in TLV status: %d", status); 2946 } 2947 log_info_key("IR", sm_persistent_ir); 2948 dkg_state = DKG_CALC_IRK; 2949 sm_run(); 2950 } 2951 2952 static void sm_handle_random_result_er(void *arg){ 2953 sm_persistent_keys_random_active = 0; 2954 if (arg){ 2955 // key generated, store in tlv 2956 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2957 log_info("Generated ER key. Store in TLV status: %d", status); 2958 } 2959 log_info_key("ER", sm_persistent_er); 2960 2961 // try load ir 2962 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2963 if (key_size == 16){ 2964 // ok, let's continue 2965 log_info("IR from TLV"); 2966 sm_handle_random_result_ir( NULL ); 2967 } else { 2968 // invalid, generate new random one 2969 sm_persistent_keys_random_active = 1; 2970 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 2971 } 2972 } 2973 2974 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2975 2976 UNUSED(channel); // ok: there is no channel 2977 UNUSED(size); // ok: fixed format HCI events 2978 2979 sm_connection_t * sm_conn; 2980 hci_con_handle_t con_handle; 2981 2982 switch (packet_type) { 2983 2984 case HCI_EVENT_PACKET: 2985 switch (hci_event_packet_get_type(packet)) { 2986 2987 case BTSTACK_EVENT_STATE: 2988 // bt stack activated, get started 2989 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2990 log_info("HCI Working!"); 2991 2992 // setup IR/ER with TLV 2993 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 2994 if (sm_tlv_impl){ 2995 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2996 if (key_size == 16){ 2997 // ok, let's continue 2998 log_info("ER from TLV"); 2999 sm_handle_random_result_er( NULL ); 3000 } else { 3001 // invalid, generate random one 3002 sm_persistent_keys_random_active = 1; 3003 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3004 } 3005 } else { 3006 sm_validate_er_ir(); 3007 dkg_state = DKG_CALC_IRK; 3008 } 3009 } 3010 break; 3011 3012 case HCI_EVENT_LE_META: 3013 switch (packet[2]) { 3014 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3015 3016 log_info("sm: connected"); 3017 3018 if (packet[3]) return; // connection failed 3019 3020 con_handle = little_endian_read_16(packet, 4); 3021 sm_conn = sm_get_connection_for_handle(con_handle); 3022 if (!sm_conn) break; 3023 3024 sm_conn->sm_handle = con_handle; 3025 sm_conn->sm_role = packet[6]; 3026 sm_conn->sm_peer_addr_type = packet[7]; 3027 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3028 3029 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3030 3031 // reset security properties 3032 sm_conn->sm_connection_encrypted = 0; 3033 sm_conn->sm_connection_authenticated = 0; 3034 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3035 sm_conn->sm_le_db_index = -1; 3036 3037 // prepare CSRK lookup (does not involve setup) 3038 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3039 3040 // just connected -> everything else happens in sm_run() 3041 if (IS_RESPONDER(sm_conn->sm_role)){ 3042 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3043 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3044 if (sm_slave_request_security) { 3045 // request security if requested by app 3046 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3047 } else { 3048 // otherwise, wait for pairing request 3049 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3050 } 3051 } 3052 break; 3053 } else { 3054 // master 3055 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3056 } 3057 break; 3058 3059 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3060 con_handle = little_endian_read_16(packet, 3); 3061 sm_conn = sm_get_connection_for_handle(con_handle); 3062 if (!sm_conn) break; 3063 3064 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3065 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3066 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3067 break; 3068 } 3069 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3070 // PH2 SEND LTK as we need to exchange keys in PH3 3071 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3072 break; 3073 } 3074 3075 // store rand and ediv 3076 reverse_64(&packet[5], sm_conn->sm_local_rand); 3077 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3078 3079 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3080 // potentially stored LTK is from the master 3081 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3082 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3083 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3084 break; 3085 } 3086 // additionally check if remote is in LE Device DB if requested 3087 switch(sm_conn->sm_irk_lookup_state){ 3088 case IRK_LOOKUP_FAILED: 3089 log_info("LTK Request: device not in device db"); 3090 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3091 break; 3092 case IRK_LOOKUP_SUCCEEDED: 3093 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3094 break; 3095 default: 3096 // wait for irk look doen 3097 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3098 break; 3099 } 3100 break; 3101 } 3102 3103 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3104 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3105 #else 3106 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3107 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3108 #endif 3109 break; 3110 3111 default: 3112 break; 3113 } 3114 break; 3115 3116 case HCI_EVENT_ENCRYPTION_CHANGE: 3117 con_handle = little_endian_read_16(packet, 3); 3118 sm_conn = sm_get_connection_for_handle(con_handle); 3119 if (!sm_conn) break; 3120 3121 sm_conn->sm_connection_encrypted = packet[5]; 3122 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3123 sm_conn->sm_actual_encryption_key_size); 3124 log_info("event handler, state %u", sm_conn->sm_engine_state); 3125 3126 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3127 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3128 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3129 // notify client, if pairing was requested before 3130 if (sm_conn->sm_pairing_requested){ 3131 sm_conn->sm_pairing_requested = 0; 3132 if (sm_conn->sm_connection_encrypted){ 3133 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3134 } else { 3135 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3136 } 3137 } 3138 sm_done_for_handle(sm_conn->sm_handle); 3139 break; 3140 } 3141 3142 if (!sm_conn->sm_connection_encrypted) break; 3143 3144 // continue pairing 3145 switch (sm_conn->sm_engine_state){ 3146 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3147 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3148 sm_done_for_handle(sm_conn->sm_handle); 3149 break; 3150 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3151 if (IS_RESPONDER(sm_conn->sm_role)){ 3152 // slave 3153 if (setup->sm_use_secure_connections){ 3154 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3155 } else { 3156 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3157 } 3158 } else { 3159 // master 3160 if (sm_key_distribution_all_received(sm_conn)){ 3161 // skip receiving keys as there are none 3162 sm_key_distribution_handle_all_received(sm_conn); 3163 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3164 } else { 3165 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3166 } 3167 } 3168 break; 3169 default: 3170 break; 3171 } 3172 break; 3173 3174 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3175 con_handle = little_endian_read_16(packet, 3); 3176 sm_conn = sm_get_connection_for_handle(con_handle); 3177 if (!sm_conn) break; 3178 3179 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3180 log_info("event handler, state %u", sm_conn->sm_engine_state); 3181 // continue if part of initial pairing 3182 switch (sm_conn->sm_engine_state){ 3183 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3184 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3185 sm_done_for_handle(sm_conn->sm_handle); 3186 break; 3187 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3188 if (IS_RESPONDER(sm_conn->sm_role)){ 3189 // slave 3190 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3191 } else { 3192 // master 3193 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3194 } 3195 break; 3196 default: 3197 break; 3198 } 3199 break; 3200 3201 3202 case HCI_EVENT_DISCONNECTION_COMPLETE: 3203 con_handle = little_endian_read_16(packet, 3); 3204 sm_done_for_handle(con_handle); 3205 sm_conn = sm_get_connection_for_handle(con_handle); 3206 if (!sm_conn) break; 3207 3208 // delete stored bonding on disconnect with authentication failure in ph0 3209 if (sm_conn->sm_role == 0 3210 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3211 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3212 le_device_db_remove(sm_conn->sm_le_db_index); 3213 } 3214 3215 // pairing failed, if it was ongoing 3216 switch (sm_conn->sm_engine_state){ 3217 case SM_GENERAL_IDLE: 3218 case SM_INITIATOR_CONNECTED: 3219 case SM_RESPONDER_IDLE: 3220 break; 3221 default: 3222 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3223 break; 3224 } 3225 3226 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3227 sm_conn->sm_handle = 0; 3228 break; 3229 3230 case HCI_EVENT_COMMAND_COMPLETE: 3231 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3232 // set local addr for le device db 3233 bd_addr_t addr; 3234 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3235 le_device_db_set_local_bd_addr(addr); 3236 } 3237 break; 3238 default: 3239 break; 3240 } 3241 break; 3242 default: 3243 break; 3244 } 3245 3246 sm_run(); 3247 } 3248 3249 static inline int sm_calc_actual_encryption_key_size(int other){ 3250 if (other < sm_min_encryption_key_size) return 0; 3251 if (other < sm_max_encryption_key_size) return other; 3252 return sm_max_encryption_key_size; 3253 } 3254 3255 3256 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3257 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3258 switch (method){ 3259 case JUST_WORKS: 3260 case NUMERIC_COMPARISON: 3261 return 1; 3262 default: 3263 return 0; 3264 } 3265 } 3266 // responder 3267 3268 static int sm_passkey_used(stk_generation_method_t method){ 3269 switch (method){ 3270 case PK_RESP_INPUT: 3271 return 1; 3272 default: 3273 return 0; 3274 } 3275 } 3276 3277 static int sm_passkey_entry(stk_generation_method_t method){ 3278 switch (method){ 3279 case PK_RESP_INPUT: 3280 case PK_INIT_INPUT: 3281 case PK_BOTH_INPUT: 3282 return 1; 3283 default: 3284 return 0; 3285 } 3286 } 3287 3288 #endif 3289 3290 /** 3291 * @return ok 3292 */ 3293 static int sm_validate_stk_generation_method(void){ 3294 // check if STK generation method is acceptable by client 3295 switch (setup->sm_stk_generation_method){ 3296 case JUST_WORKS: 3297 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3298 case PK_RESP_INPUT: 3299 case PK_INIT_INPUT: 3300 case PK_BOTH_INPUT: 3301 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3302 case OOB: 3303 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3304 case NUMERIC_COMPARISON: 3305 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3306 default: 3307 return 0; 3308 } 3309 } 3310 3311 // size of complete sm_pdu used to validate input 3312 static const uint8_t sm_pdu_size[] = { 3313 0, // 0x00 invalid opcode 3314 7, // 0x01 pairing request 3315 7, // 0x02 pairing response 3316 17, // 0x03 pairing confirm 3317 17, // 0x04 pairing random 3318 2, // 0x05 pairing failed 3319 17, // 0x06 encryption information 3320 11, // 0x07 master identification 3321 17, // 0x08 identification information 3322 8, // 0x09 identify address information 3323 17, // 0x0a signing information 3324 2, // 0x0b security request 3325 65, // 0x0c pairing public key 3326 17, // 0x0d pairing dhk check 3327 2, // 0x0e keypress notification 3328 }; 3329 3330 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3331 3332 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3333 sm_run(); 3334 } 3335 3336 if (packet_type != SM_DATA_PACKET) return; 3337 if (size == 0) return; 3338 3339 uint8_t sm_pdu_code = packet[0]; 3340 3341 // validate pdu size 3342 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3343 if (sm_pdu_size[sm_pdu_code] != size) return; 3344 3345 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3346 if (!sm_conn) return; 3347 3348 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3349 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3350 sm_done_for_handle(con_handle); 3351 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3352 return; 3353 } 3354 3355 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3356 3357 int err; 3358 UNUSED(err); 3359 3360 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3361 uint8_t buffer[5]; 3362 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3363 buffer[1] = 3; 3364 little_endian_store_16(buffer, 2, con_handle); 3365 buffer[4] = packet[1]; 3366 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3367 return; 3368 } 3369 3370 switch (sm_conn->sm_engine_state){ 3371 3372 // a sm timeout requries a new physical connection 3373 case SM_GENERAL_TIMEOUT: 3374 return; 3375 3376 #ifdef ENABLE_LE_CENTRAL 3377 3378 // Initiator 3379 case SM_INITIATOR_CONNECTED: 3380 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3381 sm_pdu_received_in_wrong_state(sm_conn); 3382 break; 3383 } 3384 3385 // IRK complete? 3386 switch (sm_conn->sm_irk_lookup_state){ 3387 case IRK_LOOKUP_FAILED: 3388 case IRK_LOOKUP_SUCCEEDED: 3389 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3390 break; 3391 default: 3392 break; 3393 } 3394 3395 // otherwise, store security request 3396 sm_conn->sm_security_request_received = 1; 3397 break; 3398 3399 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3400 // Core 5, Vol 3, Part H, 2.4.6: 3401 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3402 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3403 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3404 log_info("Ignoring Security Request"); 3405 break; 3406 } 3407 3408 // all other pdus are incorrect 3409 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3410 sm_pdu_received_in_wrong_state(sm_conn); 3411 break; 3412 } 3413 3414 // store pairing request 3415 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3416 err = sm_stk_generation_init(sm_conn); 3417 3418 #ifdef ENABLE_TESTING_SUPPORT 3419 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3420 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3421 err = test_pairing_failure; 3422 } 3423 #endif 3424 3425 if (err){ 3426 setup->sm_pairing_failed_reason = err; 3427 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3428 break; 3429 } 3430 3431 // generate random number first, if we need to show passkey 3432 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3433 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3434 break; 3435 } 3436 3437 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3438 if (setup->sm_use_secure_connections){ 3439 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3440 if (setup->sm_stk_generation_method == JUST_WORKS){ 3441 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3442 sm_trigger_user_response(sm_conn); 3443 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3444 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3445 } 3446 } else { 3447 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3448 } 3449 break; 3450 } 3451 #endif 3452 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3453 sm_trigger_user_response(sm_conn); 3454 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3455 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3456 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3457 } 3458 break; 3459 3460 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3461 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3462 sm_pdu_received_in_wrong_state(sm_conn); 3463 break; 3464 } 3465 3466 // store s_confirm 3467 reverse_128(&packet[1], setup->sm_peer_confirm); 3468 3469 #ifdef ENABLE_TESTING_SUPPORT 3470 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3471 log_info("testing_support: reset confirm value"); 3472 memset(setup->sm_peer_confirm, 0, 16); 3473 } 3474 #endif 3475 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3476 break; 3477 3478 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3479 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3480 sm_pdu_received_in_wrong_state(sm_conn); 3481 break;; 3482 } 3483 3484 // received random value 3485 reverse_128(&packet[1], setup->sm_peer_random); 3486 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3487 break; 3488 #endif 3489 3490 #ifdef ENABLE_LE_PERIPHERAL 3491 // Responder 3492 case SM_RESPONDER_IDLE: 3493 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3494 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3495 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3496 sm_pdu_received_in_wrong_state(sm_conn); 3497 break;; 3498 } 3499 3500 // store pairing request 3501 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3502 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3503 break; 3504 #endif 3505 3506 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3507 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3508 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3509 sm_pdu_received_in_wrong_state(sm_conn); 3510 break; 3511 } 3512 3513 // store public key for DH Key calculation 3514 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3515 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3516 3517 // validate public key 3518 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3519 if (err){ 3520 log_error("sm: peer public key invalid %x", err); 3521 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3522 break; 3523 } 3524 3525 // start calculating dhkey 3526 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3527 3528 3529 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3530 if (IS_RESPONDER(sm_conn->sm_role)){ 3531 // responder 3532 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3533 } else { 3534 // initiator 3535 // stk generation method 3536 // passkey entry: notify app to show passkey or to request passkey 3537 switch (setup->sm_stk_generation_method){ 3538 case JUST_WORKS: 3539 case NUMERIC_COMPARISON: 3540 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3541 break; 3542 case PK_RESP_INPUT: 3543 sm_sc_start_calculating_local_confirm(sm_conn); 3544 break; 3545 case PK_INIT_INPUT: 3546 case PK_BOTH_INPUT: 3547 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3548 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3549 break; 3550 } 3551 sm_sc_start_calculating_local_confirm(sm_conn); 3552 break; 3553 case OOB: 3554 // generate Nx 3555 log_info("Generate Na"); 3556 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3557 break; 3558 } 3559 } 3560 break; 3561 3562 case SM_SC_W4_CONFIRMATION: 3563 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3564 sm_pdu_received_in_wrong_state(sm_conn); 3565 break; 3566 } 3567 // received confirm value 3568 reverse_128(&packet[1], setup->sm_peer_confirm); 3569 3570 #ifdef ENABLE_TESTING_SUPPORT 3571 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3572 log_info("testing_support: reset confirm value"); 3573 memset(setup->sm_peer_confirm, 0, 16); 3574 } 3575 #endif 3576 if (IS_RESPONDER(sm_conn->sm_role)){ 3577 // responder 3578 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3579 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3580 // still waiting for passkey 3581 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3582 break; 3583 } 3584 } 3585 sm_sc_start_calculating_local_confirm(sm_conn); 3586 } else { 3587 // initiator 3588 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3589 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3590 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3591 } else { 3592 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3593 } 3594 } 3595 break; 3596 3597 case SM_SC_W4_PAIRING_RANDOM: 3598 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3599 sm_pdu_received_in_wrong_state(sm_conn); 3600 break; 3601 } 3602 3603 // received random value 3604 reverse_128(&packet[1], setup->sm_peer_nonce); 3605 3606 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3607 // only check for JUST WORK/NC in initiator role OR passkey entry 3608 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3609 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3610 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3611 break; 3612 } 3613 3614 // OOB 3615 if (setup->sm_stk_generation_method == OOB){ 3616 3617 // setup local random, set to zero if remote did not receive our data 3618 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3619 if (IS_RESPONDER(sm_conn->sm_role)){ 3620 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3621 log_info("Reset rb as A does not have OOB data"); 3622 memset(setup->sm_rb, 0, 16); 3623 } else { 3624 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3625 log_info("Use stored rb"); 3626 log_info_hexdump(setup->sm_rb, 16); 3627 } 3628 } else { 3629 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3630 log_info("Reset ra as B does not have OOB data"); 3631 memset(setup->sm_ra, 0, 16); 3632 } else { 3633 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3634 log_info("Use stored ra"); 3635 log_info_hexdump(setup->sm_ra, 16); 3636 } 3637 } 3638 3639 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3640 if (setup->sm_have_oob_data){ 3641 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3642 break; 3643 } 3644 } 3645 3646 // TODO: we only get here for Responder role with JW/NC 3647 sm_sc_state_after_receiving_random(sm_conn); 3648 break; 3649 3650 case SM_SC_W2_CALCULATE_G2: 3651 case SM_SC_W4_CALCULATE_G2: 3652 case SM_SC_W4_CALCULATE_DHKEY: 3653 case SM_SC_W2_CALCULATE_F5_SALT: 3654 case SM_SC_W4_CALCULATE_F5_SALT: 3655 case SM_SC_W2_CALCULATE_F5_MACKEY: 3656 case SM_SC_W4_CALCULATE_F5_MACKEY: 3657 case SM_SC_W2_CALCULATE_F5_LTK: 3658 case SM_SC_W4_CALCULATE_F5_LTK: 3659 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3660 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3661 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3662 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3663 sm_pdu_received_in_wrong_state(sm_conn); 3664 break; 3665 } 3666 // store DHKey Check 3667 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3668 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3669 3670 // have we been only waiting for dhkey check command? 3671 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3672 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3673 } 3674 break; 3675 #endif 3676 3677 #ifdef ENABLE_LE_PERIPHERAL 3678 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3679 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3680 sm_pdu_received_in_wrong_state(sm_conn); 3681 break; 3682 } 3683 3684 // received confirm value 3685 reverse_128(&packet[1], setup->sm_peer_confirm); 3686 3687 #ifdef ENABLE_TESTING_SUPPORT 3688 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3689 log_info("testing_support: reset confirm value"); 3690 memset(setup->sm_peer_confirm, 0, 16); 3691 } 3692 #endif 3693 // notify client to hide shown passkey 3694 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3695 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3696 } 3697 3698 // handle user cancel pairing? 3699 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3700 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3701 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3702 break; 3703 } 3704 3705 // wait for user action? 3706 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3707 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3708 break; 3709 } 3710 3711 // calculate and send local_confirm 3712 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3713 break; 3714 3715 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3716 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3717 sm_pdu_received_in_wrong_state(sm_conn); 3718 break;; 3719 } 3720 3721 // received random value 3722 reverse_128(&packet[1], setup->sm_peer_random); 3723 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3724 break; 3725 #endif 3726 3727 case SM_PH3_RECEIVE_KEYS: 3728 switch(sm_pdu_code){ 3729 case SM_CODE_ENCRYPTION_INFORMATION: 3730 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3731 reverse_128(&packet[1], setup->sm_peer_ltk); 3732 break; 3733 3734 case SM_CODE_MASTER_IDENTIFICATION: 3735 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3736 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3737 reverse_64(&packet[3], setup->sm_peer_rand); 3738 break; 3739 3740 case SM_CODE_IDENTITY_INFORMATION: 3741 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3742 reverse_128(&packet[1], setup->sm_peer_irk); 3743 break; 3744 3745 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3746 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3747 setup->sm_peer_addr_type = packet[1]; 3748 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3749 break; 3750 3751 case SM_CODE_SIGNING_INFORMATION: 3752 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3753 reverse_128(&packet[1], setup->sm_peer_csrk); 3754 break; 3755 default: 3756 // Unexpected PDU 3757 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3758 break; 3759 } 3760 // done with key distribution? 3761 if (sm_key_distribution_all_received(sm_conn)){ 3762 3763 sm_key_distribution_handle_all_received(sm_conn); 3764 3765 if (IS_RESPONDER(sm_conn->sm_role)){ 3766 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3767 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3768 } else { 3769 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3770 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3771 sm_done_for_handle(sm_conn->sm_handle); 3772 } 3773 } else { 3774 if (setup->sm_use_secure_connections){ 3775 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3776 } else { 3777 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3778 } 3779 } 3780 } 3781 break; 3782 default: 3783 // Unexpected PDU 3784 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3785 break; 3786 } 3787 3788 // try to send preparared packet 3789 sm_run(); 3790 } 3791 3792 // Security Manager Client API 3793 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3794 sm_get_oob_data = get_oob_data_callback; 3795 } 3796 3797 void sm_register_sc_oob_data_callback( int (*get_sc_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random)){ 3798 sm_get_sc_oob_data = get_sc_oob_data_callback; 3799 } 3800 3801 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3802 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3803 } 3804 3805 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3806 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3807 } 3808 3809 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3810 sm_min_encryption_key_size = min_size; 3811 sm_max_encryption_key_size = max_size; 3812 } 3813 3814 void sm_set_authentication_requirements(uint8_t auth_req){ 3815 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3816 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3817 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3818 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3819 } 3820 #endif 3821 sm_auth_req = auth_req; 3822 } 3823 3824 void sm_set_io_capabilities(io_capability_t io_capability){ 3825 sm_io_capabilities = io_capability; 3826 } 3827 3828 #ifdef ENABLE_LE_PERIPHERAL 3829 void sm_set_request_security(int enable){ 3830 sm_slave_request_security = enable; 3831 } 3832 #endif 3833 3834 void sm_set_er(sm_key_t er){ 3835 memcpy(sm_persistent_er, er, 16); 3836 } 3837 3838 void sm_set_ir(sm_key_t ir){ 3839 memcpy(sm_persistent_ir, ir, 16); 3840 } 3841 3842 // Testing support only 3843 void sm_test_set_irk(sm_key_t irk){ 3844 memcpy(sm_persistent_irk, irk, 16); 3845 dkg_state = DKG_CALC_DHK; 3846 } 3847 3848 void sm_test_use_fixed_local_csrk(void){ 3849 test_use_fixed_local_csrk = 1; 3850 } 3851 3852 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3853 static void sm_ec_generated(void * arg){ 3854 UNUSED(arg); 3855 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3856 // trigger pairing if pending for ec key 3857 sm_run(); 3858 } 3859 static void sm_ec_generate_new_key(void){ 3860 log_info("sm: generate new ec key"); 3861 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3862 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3863 } 3864 #endif 3865 3866 #ifdef ENABLE_TESTING_SUPPORT 3867 void sm_test_set_pairing_failure(int reason){ 3868 test_pairing_failure = reason; 3869 } 3870 #endif 3871 3872 void sm_init(void){ 3873 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3874 sm_er_ir_set_default(); 3875 3876 // defaults 3877 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3878 | SM_STK_GENERATION_METHOD_OOB 3879 | SM_STK_GENERATION_METHOD_PASSKEY 3880 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3881 3882 sm_max_encryption_key_size = 16; 3883 sm_min_encryption_key_size = 7; 3884 3885 sm_fixed_passkey_in_display_role = 0xffffffff; 3886 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3887 3888 #ifdef USE_CMAC_ENGINE 3889 sm_cmac_active = 0; 3890 #endif 3891 dkg_state = DKG_W4_WORKING; 3892 rau_state = RAU_IDLE; 3893 sm_aes128_state = SM_AES128_IDLE; 3894 sm_address_resolution_test = -1; // no private address to resolve yet 3895 sm_address_resolution_ah_calculation_active = 0; 3896 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3897 sm_address_resolution_general_queue = NULL; 3898 3899 gap_random_adress_update_period = 15 * 60 * 1000L; 3900 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3901 3902 test_use_fixed_local_csrk = 0; 3903 3904 // register for HCI Events from HCI 3905 hci_event_callback_registration.callback = &sm_event_packet_handler; 3906 hci_add_event_handler(&hci_event_callback_registration); 3907 3908 // 3909 btstack_crypto_init(); 3910 3911 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3912 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3913 3914 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3915 sm_ec_generate_new_key(); 3916 #endif 3917 } 3918 3919 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3920 sm_fixed_passkey_in_display_role = passkey; 3921 } 3922 3923 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3924 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3925 } 3926 3927 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3928 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3929 if (!hci_con) return NULL; 3930 return &hci_con->sm_connection; 3931 } 3932 3933 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3934 switch (sm_conn->sm_engine_state){ 3935 case SM_GENERAL_IDLE: 3936 case SM_RESPONDER_IDLE: 3937 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3938 sm_run(); 3939 break; 3940 default: 3941 break; 3942 } 3943 } 3944 3945 /** 3946 * @brief Trigger Security Request 3947 */ 3948 void sm_send_security_request(hci_con_handle_t con_handle){ 3949 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3950 if (!sm_conn) return; 3951 sm_send_security_request_for_connection(sm_conn); 3952 } 3953 3954 // request pairing 3955 void sm_request_pairing(hci_con_handle_t con_handle){ 3956 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3957 if (!sm_conn) return; // wrong connection 3958 3959 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3960 if (IS_RESPONDER(sm_conn->sm_role)){ 3961 sm_send_security_request_for_connection(sm_conn); 3962 } else { 3963 // used as a trigger to start central/master/initiator security procedures 3964 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3965 uint8_t ltk[16]; 3966 switch (sm_conn->sm_irk_lookup_state){ 3967 case IRK_LOOKUP_SUCCEEDED: 3968 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 3969 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3970 int have_ltk = !sm_is_null_key(ltk); 3971 log_info("have ltk %u", have_ltk); 3972 // trigger 'pairing complete' event on encryption change 3973 sm_conn->sm_pairing_requested = 1; 3974 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3975 break; 3976 #endif 3977 /* explicit fall-through */ 3978 3979 case IRK_LOOKUP_FAILED: 3980 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3981 break; 3982 default: 3983 log_info("irk lookup pending"); 3984 sm_conn->sm_pairing_requested = 1; 3985 break; 3986 } 3987 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3988 sm_conn->sm_pairing_requested = 1; 3989 } 3990 } 3991 sm_run(); 3992 } 3993 3994 // called by client app on authorization request 3995 void sm_authorization_decline(hci_con_handle_t con_handle){ 3996 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3997 if (!sm_conn) return; // wrong connection 3998 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3999 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4000 } 4001 4002 void sm_authorization_grant(hci_con_handle_t con_handle){ 4003 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4004 if (!sm_conn) return; // wrong connection 4005 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4006 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4007 } 4008 4009 // GAP Bonding API 4010 4011 void sm_bonding_decline(hci_con_handle_t con_handle){ 4012 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4013 if (!sm_conn) return; // wrong connection 4014 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4015 log_info("decline, state %u", sm_conn->sm_engine_state); 4016 switch(sm_conn->sm_engine_state){ 4017 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4018 case SM_SC_W4_USER_RESPONSE: 4019 case SM_SC_W4_CONFIRMATION: 4020 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4021 #endif 4022 case SM_PH1_W4_USER_RESPONSE: 4023 switch (setup->sm_stk_generation_method){ 4024 case PK_RESP_INPUT: 4025 case PK_INIT_INPUT: 4026 case PK_BOTH_INPUT: 4027 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4028 break; 4029 case NUMERIC_COMPARISON: 4030 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4031 break; 4032 case JUST_WORKS: 4033 case OOB: 4034 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4035 break; 4036 } 4037 break; 4038 default: 4039 break; 4040 } 4041 sm_run(); 4042 } 4043 4044 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4045 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4046 if (!sm_conn) return; // wrong connection 4047 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4048 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4049 if (setup->sm_use_secure_connections){ 4050 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4051 } else { 4052 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4053 } 4054 } 4055 4056 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4057 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4058 sm_sc_prepare_dhkey_check(sm_conn); 4059 } 4060 #endif 4061 4062 sm_run(); 4063 } 4064 4065 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4066 // for now, it's the same 4067 sm_just_works_confirm(con_handle); 4068 } 4069 4070 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4071 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4072 if (!sm_conn) return; // wrong connection 4073 sm_reset_tk(); 4074 big_endian_store_32(setup->sm_tk, 12, passkey); 4075 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4076 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4077 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4078 } 4079 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4080 memcpy(setup->sm_ra, setup->sm_tk, 16); 4081 memcpy(setup->sm_rb, setup->sm_tk, 16); 4082 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4083 sm_sc_start_calculating_local_confirm(sm_conn); 4084 } 4085 #endif 4086 sm_run(); 4087 } 4088 4089 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4090 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4091 if (!sm_conn) return; // wrong connection 4092 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4093 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4094 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4095 switch (action){ 4096 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4097 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4098 flags |= (1 << action); 4099 break; 4100 case SM_KEYPRESS_PASSKEY_CLEARED: 4101 // clear counter, keypress & erased flags + set passkey cleared 4102 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4103 break; 4104 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4105 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4106 // erase actions queued 4107 num_actions--; 4108 if (num_actions == 0){ 4109 // clear counter, keypress & erased flags 4110 flags &= 0x19; 4111 } 4112 break; 4113 } 4114 num_actions++; 4115 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4116 break; 4117 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4118 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4119 // enter actions queued 4120 num_actions--; 4121 if (num_actions == 0){ 4122 // clear counter, keypress & erased flags 4123 flags &= 0x19; 4124 } 4125 break; 4126 } 4127 num_actions++; 4128 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4129 break; 4130 default: 4131 break; 4132 } 4133 setup->sm_keypress_notification = (num_actions << 5) | flags; 4134 sm_run(); 4135 } 4136 4137 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4138 static void sm_handle_random_result_oob(void * arg){ 4139 UNUSED(arg); 4140 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4141 sm_run(); 4142 } 4143 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4144 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4145 sm_sc_oob_callback = callback; 4146 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4147 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4148 return 0; 4149 } 4150 #endif 4151 4152 /** 4153 * @brief Identify device in LE Device DB 4154 * @param handle 4155 * @returns index from le_device_db or -1 if not found/identified 4156 */ 4157 int sm_le_device_index(hci_con_handle_t con_handle ){ 4158 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4159 if (!sm_conn) return -1; 4160 return sm_conn->sm_le_db_index; 4161 } 4162 4163 static int gap_random_address_type_requires_updates(void){ 4164 switch (gap_random_adress_type){ 4165 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4166 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4167 return 0; 4168 default: 4169 return 1; 4170 } 4171 } 4172 4173 static uint8_t own_address_type(void){ 4174 switch (gap_random_adress_type){ 4175 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4176 return BD_ADDR_TYPE_LE_PUBLIC; 4177 default: 4178 return BD_ADDR_TYPE_LE_RANDOM; 4179 } 4180 } 4181 4182 // GAP LE API 4183 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4184 gap_random_address_update_stop(); 4185 gap_random_adress_type = random_address_type; 4186 hci_le_set_own_address_type(own_address_type()); 4187 if (!gap_random_address_type_requires_updates()) return; 4188 gap_random_address_update_start(); 4189 gap_random_address_trigger(); 4190 } 4191 4192 gap_random_address_type_t gap_random_address_get_mode(void){ 4193 return gap_random_adress_type; 4194 } 4195 4196 void gap_random_address_set_update_period(int period_ms){ 4197 gap_random_adress_update_period = period_ms; 4198 if (!gap_random_address_type_requires_updates()) return; 4199 gap_random_address_update_stop(); 4200 gap_random_address_update_start(); 4201 } 4202 4203 void gap_random_address_set(bd_addr_t addr){ 4204 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4205 memcpy(sm_random_address, addr, 6); 4206 rau_state = RAU_SET_ADDRESS; 4207 sm_run(); 4208 } 4209 4210 #ifdef ENABLE_LE_PERIPHERAL 4211 /* 4212 * @brief Set Advertisement Paramters 4213 * @param adv_int_min 4214 * @param adv_int_max 4215 * @param adv_type 4216 * @param direct_address_type 4217 * @param direct_address 4218 * @param channel_map 4219 * @param filter_policy 4220 * 4221 * @note own_address_type is used from gap_random_address_set_mode 4222 */ 4223 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4224 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4225 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4226 direct_address_typ, direct_address, channel_map, filter_policy); 4227 } 4228 #endif 4229 4230 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4231 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4232 // wrong connection 4233 if (!sm_conn) return 0; 4234 // already encrypted 4235 if (sm_conn->sm_connection_encrypted) return 0; 4236 // only central can re-encrypt 4237 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4238 // irk status? 4239 switch(sm_conn->sm_irk_lookup_state){ 4240 case IRK_LOOKUP_FAILED: 4241 // done, cannot setup encryption 4242 return 0; 4243 case IRK_LOOKUP_SUCCEEDED: 4244 break; 4245 default: 4246 // IR Lookup pending 4247 return 1; 4248 } 4249 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4250 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4251 } 4252