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 static void sm_done_for_handle(hci_con_handle_t con_handle); 397 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 398 static inline int sm_calc_actual_encryption_key_size(int other); 399 static int sm_validate_stk_generation_method(void); 400 static void sm_handle_encryption_result_address_resolution(void *arg); 401 static void sm_handle_encryption_result_dkg_dhk(void *arg); 402 static void sm_handle_encryption_result_dkg_irk(void *arg); 403 static void sm_handle_encryption_result_enc_a(void *arg); 404 static void sm_handle_encryption_result_enc_b(void *arg); 405 static void sm_handle_encryption_result_enc_c(void *arg); 406 static void sm_handle_encryption_result_enc_csrk(void *arg); 407 static void sm_handle_encryption_result_enc_d(void * arg); 408 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 409 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 410 #ifdef ENABLE_LE_PERIPHERAL 411 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 412 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 413 #endif 414 static void sm_handle_encryption_result_enc_stk(void *arg); 415 static void sm_handle_encryption_result_rau(void *arg); 416 static void sm_handle_random_result_ph2_tk(void * arg); 417 static void sm_handle_random_result_rau(void * arg); 418 #ifdef ENABLE_LE_SECURE_CONNECTIONS 419 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)); 420 static void sm_ec_generate_new_key(void); 421 static void sm_handle_random_result_sc_get_random(void * arg); 422 static int sm_passkey_entry(stk_generation_method_t method); 423 #endif 424 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 425 426 static void log_info_hex16(const char * name, uint16_t value){ 427 log_info("%-6s 0x%04x", name, value); 428 } 429 430 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 431 // return packet[0]; 432 // } 433 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 434 return packet[1]; 435 } 436 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 437 return packet[2]; 438 } 439 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 440 return packet[3]; 441 } 442 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 443 return packet[4]; 444 } 445 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 446 return packet[5]; 447 } 448 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 449 return packet[6]; 450 } 451 452 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 453 packet[0] = code; 454 } 455 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 456 packet[1] = io_capability; 457 } 458 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 459 packet[2] = oob_data_flag; 460 } 461 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 462 packet[3] = auth_req; 463 } 464 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 465 packet[4] = max_encryption_key_size; 466 } 467 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 468 packet[5] = initiator_key_distribution; 469 } 470 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 471 packet[6] = responder_key_distribution; 472 } 473 474 // @returns 1 if all bytes are 0 475 static int sm_is_null(uint8_t * data, int size){ 476 int i; 477 for (i=0; i < size ; i++){ 478 if (data[i]) return 0; 479 } 480 return 1; 481 } 482 483 static int sm_is_null_random(uint8_t random[8]){ 484 return sm_is_null(random, 8); 485 } 486 487 static int sm_is_null_key(uint8_t * key){ 488 return sm_is_null(key, 16); 489 } 490 491 // Key utils 492 static void sm_reset_tk(void){ 493 int i; 494 for (i=0;i<16;i++){ 495 setup->sm_tk[i] = 0; 496 } 497 } 498 499 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 500 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 501 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 502 int i; 503 for (i = max_encryption_size ; i < 16 ; i++){ 504 key[15-i] = 0; 505 } 506 } 507 508 // ER / IR checks 509 static void sm_er_ir_set_default(void){ 510 int i; 511 for (i=0;i<16;i++){ 512 sm_persistent_er[i] = 0x30 + i; 513 sm_persistent_ir[i] = 0x90 + i; 514 } 515 } 516 517 static int sm_er_is_default(void){ 518 int i; 519 for (i=0;i<16;i++){ 520 if (sm_persistent_er[i] != (0x30+i)) return 0; 521 } 522 return 1; 523 } 524 525 static int sm_ir_is_default(void){ 526 int i; 527 for (i=0;i<16;i++){ 528 if (sm_persistent_ir[i] != (0x90+i)) return 0; 529 } 530 return 1; 531 } 532 533 // SMP Timeout implementation 534 535 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 536 // the Security Manager Timer shall be reset and started. 537 // 538 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 539 // 540 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 541 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 542 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 543 // established. 544 545 static void sm_timeout_handler(btstack_timer_source_t * timer){ 546 log_info("SM timeout"); 547 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 548 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 549 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 550 sm_done_for_handle(sm_conn->sm_handle); 551 552 // trigger handling of next ready connection 553 sm_run(); 554 } 555 static void sm_timeout_start(sm_connection_t * sm_conn){ 556 btstack_run_loop_remove_timer(&setup->sm_timeout); 557 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 558 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 559 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 560 btstack_run_loop_add_timer(&setup->sm_timeout); 561 } 562 static void sm_timeout_stop(void){ 563 btstack_run_loop_remove_timer(&setup->sm_timeout); 564 } 565 static void sm_timeout_reset(sm_connection_t * sm_conn){ 566 sm_timeout_stop(); 567 sm_timeout_start(sm_conn); 568 } 569 570 // end of sm timeout 571 572 // GAP Random Address updates 573 static gap_random_address_type_t gap_random_adress_type; 574 static btstack_timer_source_t gap_random_address_update_timer; 575 static uint32_t gap_random_adress_update_period; 576 577 static void gap_random_address_trigger(void){ 578 log_info("gap_random_address_trigger, state %u", rau_state); 579 if (rau_state != RAU_IDLE) return; 580 rau_state = RAU_GET_RANDOM; 581 sm_run(); 582 } 583 584 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 585 UNUSED(timer); 586 587 log_info("GAP Random Address Update due"); 588 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 589 btstack_run_loop_add_timer(&gap_random_address_update_timer); 590 gap_random_address_trigger(); 591 } 592 593 static void gap_random_address_update_start(void){ 594 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 595 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 596 btstack_run_loop_add_timer(&gap_random_address_update_timer); 597 } 598 599 static void gap_random_address_update_stop(void){ 600 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 601 } 602 603 // ah(k,r) helper 604 // r = padding || r 605 // r - 24 bit value 606 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 607 // r'= padding || r 608 memset(r_prime, 0, 16); 609 memcpy(&r_prime[13], r, 3); 610 } 611 612 // d1 helper 613 // d' = padding || r || d 614 // d,r - 16 bit values 615 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 616 // d'= padding || r || d 617 memset(d1_prime, 0, 16); 618 big_endian_store_16(d1_prime, 12, r); 619 big_endian_store_16(d1_prime, 14, d); 620 } 621 622 // dm helper 623 // r’ = padding || r 624 // r - 64 bit value 625 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 626 memset(r_prime, 0, 16); 627 memcpy(&r_prime[8], r, 8); 628 } 629 630 // calculate arguments for first AES128 operation in C1 function 631 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){ 632 633 // p1 = pres || preq || rat’ || iat’ 634 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 635 // cant octet of pres becomes the most significant octet of p1. 636 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 637 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 638 // p1 is 0x05000800000302070710000001010001." 639 640 sm_key_t p1; 641 reverse_56(pres, &p1[0]); 642 reverse_56(preq, &p1[7]); 643 p1[14] = rat; 644 p1[15] = iat; 645 log_info_key("p1", p1); 646 log_info_key("r", r); 647 648 // t1 = r xor p1 649 int i; 650 for (i=0;i<16;i++){ 651 t1[i] = r[i] ^ p1[i]; 652 } 653 log_info_key("t1", t1); 654 } 655 656 // calculate arguments for second AES128 operation in C1 function 657 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 658 // p2 = padding || ia || ra 659 // "The least significant octet of ra becomes the least significant octet of p2 and 660 // the most significant octet of padding becomes the most significant octet of p2. 661 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 662 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 663 664 sm_key_t p2; 665 memset(p2, 0, 16); 666 memcpy(&p2[4], ia, 6); 667 memcpy(&p2[10], ra, 6); 668 log_info_key("p2", p2); 669 670 // c1 = e(k, t2_xor_p2) 671 int i; 672 for (i=0;i<16;i++){ 673 t3[i] = t2[i] ^ p2[i]; 674 } 675 log_info_key("t3", t3); 676 } 677 678 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 679 log_info_key("r1", r1); 680 log_info_key("r2", r2); 681 memcpy(&r_prime[8], &r2[8], 8); 682 memcpy(&r_prime[0], &r1[8], 8); 683 } 684 685 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 686 UNUSED(channel); 687 688 // log event 689 hci_dump_packet(packet_type, 1, packet, size); 690 // dispatch to all event handlers 691 btstack_linked_list_iterator_t it; 692 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 693 while (btstack_linked_list_iterator_has_next(&it)){ 694 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 695 entry->callback(packet_type, 0, packet, size); 696 } 697 } 698 699 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){ 700 event[0] = type; 701 event[1] = event_size - 2; 702 little_endian_store_16(event, 2, con_handle); 703 event[4] = addr_type; 704 reverse_bd_addr(address, &event[5]); 705 } 706 707 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 708 uint8_t event[11]; 709 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 710 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 711 } 712 713 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){ 714 uint8_t event[15]; 715 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 716 little_endian_store_32(event, 11, passkey); 717 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 718 } 719 720 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){ 721 // fetch addr and addr type from db, only called for valid entries 722 bd_addr_t identity_address; 723 int identity_address_type; 724 le_device_db_info(index, &identity_address_type, identity_address, NULL); 725 726 uint8_t event[20]; 727 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 728 event[11] = identity_address_type; 729 reverse_bd_addr(identity_address, &event[12]); 730 little_endian_store_16(event, 18, index); 731 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 732 } 733 734 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){ 735 uint8_t event[12]; 736 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 737 event[11] = status; 738 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 739 } 740 741 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 742 uint8_t event[13]; 743 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 744 event[11] = status; 745 event[12] = reason; 746 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 747 } 748 749 // decide on stk generation based on 750 // - pairing request 751 // - io capabilities 752 // - OOB data availability 753 static void sm_setup_tk(void){ 754 755 // default: just works 756 setup->sm_stk_generation_method = JUST_WORKS; 757 758 #ifdef ENABLE_LE_SECURE_CONNECTIONS 759 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 760 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 761 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 762 #else 763 setup->sm_use_secure_connections = 0; 764 #endif 765 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 766 767 768 // decide if OOB will be used based on SC vs. Legacy and oob flags 769 int use_oob = 0; 770 if (setup->sm_use_secure_connections){ 771 // In LE Secure Connections pairing, the out of band method is used if at least 772 // one device has the peer device's out of band authentication data available. 773 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 774 } else { 775 // In LE legacy pairing, the out of band method is used if both the devices have 776 // the other device's out of band authentication data available. 777 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 778 } 779 if (use_oob){ 780 log_info("SM: have OOB data"); 781 log_info_key("OOB", setup->sm_tk); 782 setup->sm_stk_generation_method = OOB; 783 return; 784 } 785 786 // If both devices have not set the MITM option in the Authentication Requirements 787 // Flags, then the IO capabilities shall be ignored and the Just Works association 788 // model shall be used. 789 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 790 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 791 log_info("SM: MITM not required by both -> JUST WORKS"); 792 return; 793 } 794 795 // Reset TK as it has been setup in sm_init_setup 796 sm_reset_tk(); 797 798 // Also use just works if unknown io capabilites 799 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)){ 800 return; 801 } 802 803 // Otherwise the IO capabilities of the devices shall be used to determine the 804 // pairing method as defined in Table 2.4. 805 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 806 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 807 808 #ifdef ENABLE_LE_SECURE_CONNECTIONS 809 // table not define by default 810 if (setup->sm_use_secure_connections){ 811 generation_method = stk_generation_method_with_secure_connection; 812 } 813 #endif 814 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)]; 815 816 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 817 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); 818 } 819 820 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 821 int flags = 0; 822 if (key_set & SM_KEYDIST_ENC_KEY){ 823 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 824 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 825 } 826 if (key_set & SM_KEYDIST_ID_KEY){ 827 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 828 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 829 } 830 if (key_set & SM_KEYDIST_SIGN){ 831 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 832 } 833 return flags; 834 } 835 836 static void sm_setup_key_distribution(uint8_t key_set){ 837 setup->sm_key_distribution_received_set = 0; 838 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 839 } 840 841 // CSRK Key Lookup 842 843 844 static int sm_address_resolution_idle(void){ 845 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 846 } 847 848 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){ 849 memcpy(sm_address_resolution_address, addr, 6); 850 sm_address_resolution_addr_type = addr_type; 851 sm_address_resolution_test = 0; 852 sm_address_resolution_mode = mode; 853 sm_address_resolution_context = context; 854 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 855 } 856 857 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 858 // check if already in list 859 btstack_linked_list_iterator_t it; 860 sm_lookup_entry_t * entry; 861 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 862 while(btstack_linked_list_iterator_has_next(&it)){ 863 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 864 if (entry->address_type != address_type) continue; 865 if (memcmp(entry->address, address, 6)) continue; 866 // already in list 867 return BTSTACK_BUSY; 868 } 869 entry = btstack_memory_sm_lookup_entry_get(); 870 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 871 entry->address_type = (bd_addr_type_t) address_type; 872 memcpy(entry->address, address, 6); 873 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 874 sm_run(); 875 return 0; 876 } 877 878 // CMAC calculation using AES Engineq 879 #ifdef USE_CMAC_ENGINE 880 881 static void sm_cmac_done_trampoline(void * arg){ 882 UNUSED(arg); 883 sm_cmac_active = 0; 884 (*sm_cmac_done_callback)(sm_cmac_hash); 885 sm_run(); 886 } 887 888 int sm_cmac_ready(void){ 889 return sm_cmac_active == 0; 890 } 891 #endif 892 893 #ifdef ENABLE_LE_SECURE_CONNECTIONS 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, 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, 1); 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, 0); 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 int secure_connection; 1785 1786 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1787 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1788 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1789 log_info("db index %u, key size %u, authenticated %u, authorized %u, secure connetion %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized, secure_connection); 1790 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1791 sm_connection->sm_connection_authenticated = authenticated; 1792 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1793 sm_connection->sm_connection_sc = secure_connection; 1794 } 1795 #endif 1796 1797 #ifdef ENABLE_LE_PERIPHERAL 1798 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1799 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1800 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1801 // re-establish used key encryption size 1802 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1803 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1804 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1805 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1806 // Legacy paring -> not SC 1807 sm_connection->sm_connection_sc = 0; 1808 log_info("sm: received ltk request with key size %u, authenticated %u", 1809 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1810 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1811 sm_run(); 1812 } 1813 #endif 1814 1815 static void sm_run(void){ 1816 1817 btstack_linked_list_iterator_t it; 1818 1819 // assert that stack has already bootet 1820 if (hci_get_state() != HCI_STATE_WORKING) return; 1821 1822 // assert that we can send at least commands 1823 if (!hci_can_send_command_packet_now()) return; 1824 1825 // pause until IR/ER are ready 1826 if (sm_persistent_keys_random_active) return; 1827 1828 // 1829 // non-connection related behaviour 1830 // 1831 1832 // distributed key generation 1833 switch (dkg_state){ 1834 case DKG_CALC_IRK: 1835 // already busy? 1836 if (sm_aes128_state == SM_AES128_IDLE) { 1837 log_info("DKG_CALC_IRK started"); 1838 // IRK = d1(IR, 1, 0) 1839 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1840 sm_aes128_state = SM_AES128_ACTIVE; 1841 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1842 return; 1843 } 1844 break; 1845 case DKG_CALC_DHK: 1846 // already busy? 1847 if (sm_aes128_state == SM_AES128_IDLE) { 1848 log_info("DKG_CALC_DHK started"); 1849 // DHK = d1(IR, 3, 0) 1850 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1851 sm_aes128_state = SM_AES128_ACTIVE; 1852 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1853 return; 1854 } 1855 break; 1856 default: 1857 break; 1858 } 1859 1860 // random address updates 1861 switch (rau_state){ 1862 case RAU_GET_RANDOM: 1863 rau_state = RAU_W4_RANDOM; 1864 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1865 return; 1866 case RAU_GET_ENC: 1867 // already busy? 1868 if (sm_aes128_state == SM_AES128_IDLE) { 1869 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1870 sm_aes128_state = SM_AES128_ACTIVE; 1871 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1872 return; 1873 } 1874 break; 1875 case RAU_SET_ADDRESS: 1876 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1877 rau_state = RAU_IDLE; 1878 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1879 return; 1880 default: 1881 break; 1882 } 1883 1884 // CSRK Lookup 1885 // -- if csrk lookup ready, find connection that require csrk lookup 1886 if (sm_address_resolution_idle()){ 1887 hci_connections_get_iterator(&it); 1888 while(btstack_linked_list_iterator_has_next(&it)){ 1889 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1890 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1891 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1892 // and start lookup 1893 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); 1894 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1895 break; 1896 } 1897 } 1898 } 1899 1900 // -- if csrk lookup ready, resolved addresses for received addresses 1901 if (sm_address_resolution_idle()) { 1902 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1903 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1904 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1905 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1906 btstack_memory_sm_lookup_entry_free(entry); 1907 } 1908 } 1909 1910 // -- Continue with CSRK device lookup by public or resolvable private address 1911 if (!sm_address_resolution_idle()){ 1912 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1913 while (sm_address_resolution_test < le_device_db_max_count()){ 1914 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1915 bd_addr_t addr; 1916 sm_key_t irk; 1917 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1918 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1919 1920 // skip unused entries 1921 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1922 sm_address_resolution_test++; 1923 continue; 1924 } 1925 1926 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1927 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1928 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1929 break; 1930 } 1931 1932 // if connection type is public, it must be a different one 1933 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1934 sm_address_resolution_test++; 1935 continue; 1936 } 1937 1938 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1939 1940 log_info("LE Device Lookup: calculate AH"); 1941 log_info_key("IRK", irk); 1942 1943 memcpy(sm_aes128_key, irk, 16); 1944 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1945 sm_address_resolution_ah_calculation_active = 1; 1946 sm_aes128_state = SM_AES128_ACTIVE; 1947 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1948 return; 1949 } 1950 1951 if (sm_address_resolution_test >= le_device_db_max_count()){ 1952 log_info("LE Device Lookup: not found"); 1953 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1954 } 1955 } 1956 1957 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1958 switch (sm_sc_oob_state){ 1959 case SM_SC_OOB_W2_CALC_CONFIRM: 1960 if (!sm_cmac_ready()) break; 1961 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1962 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1963 return; 1964 default: 1965 break; 1966 } 1967 #endif 1968 1969 // assert that we can send at least commands - cmd might have been sent by crypto engine 1970 if (!hci_can_send_command_packet_now()) return; 1971 1972 // handle basic actions that don't requires the full context 1973 hci_connections_get_iterator(&it); 1974 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1975 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1976 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1977 switch(sm_connection->sm_engine_state){ 1978 // responder side 1979 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1980 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1981 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1982 return; 1983 1984 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1985 case SM_SC_RECEIVED_LTK_REQUEST: 1986 switch (sm_connection->sm_irk_lookup_state){ 1987 case IRK_LOOKUP_FAILED: 1988 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1989 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1990 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1991 return; 1992 default: 1993 break; 1994 } 1995 break; 1996 #endif 1997 default: 1998 break; 1999 } 2000 } 2001 2002 // 2003 // active connection handling 2004 // -- use loop to handle next connection if lock on setup context is released 2005 2006 while (1) { 2007 2008 // Find connections that requires setup context and make active if no other is locked 2009 hci_connections_get_iterator(&it); 2010 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2011 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2012 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2013 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2014 int done = 1; 2015 int err; 2016 UNUSED(err); 2017 2018 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2019 // assert ec key is ready 2020 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2021 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2022 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2023 sm_ec_generate_new_key(); 2024 } 2025 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2026 continue; 2027 } 2028 } 2029 #endif 2030 2031 switch (sm_connection->sm_engine_state) { 2032 #ifdef ENABLE_LE_PERIPHERAL 2033 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2034 // send packet if possible, 2035 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2036 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2037 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2038 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2039 } else { 2040 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2041 } 2042 // don't lock sxetup context yet 2043 done = 0; 2044 break; 2045 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2046 sm_reset_setup(); 2047 sm_init_setup(sm_connection); 2048 // recover pairing request 2049 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2050 err = sm_stk_generation_init(sm_connection); 2051 2052 #ifdef ENABLE_TESTING_SUPPORT 2053 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2054 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2055 err = test_pairing_failure; 2056 } 2057 #endif 2058 if (err){ 2059 setup->sm_pairing_failed_reason = err; 2060 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2061 break; 2062 } 2063 sm_timeout_start(sm_connection); 2064 // generate random number first, if we need to show passkey 2065 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2066 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2067 break; 2068 } 2069 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2070 break; 2071 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2072 sm_reset_setup(); 2073 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2074 break; 2075 2076 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2077 case SM_SC_RECEIVED_LTK_REQUEST: 2078 switch (sm_connection->sm_irk_lookup_state){ 2079 case IRK_LOOKUP_SUCCEEDED: 2080 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2081 // start using context by loading security info 2082 sm_reset_setup(); 2083 sm_load_security_info(sm_connection); 2084 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2085 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2086 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2087 break; 2088 } 2089 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2090 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2091 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2092 // don't lock setup context yet 2093 return; 2094 default: 2095 // just wait until IRK lookup is completed 2096 // don't lock setup context yet 2097 done = 0; 2098 break; 2099 } 2100 break; 2101 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2102 #endif /* ENABLE_LE_PERIPHERAL */ 2103 2104 #ifdef ENABLE_LE_CENTRAL 2105 case SM_INITIATOR_PH0_HAS_LTK: 2106 sm_reset_setup(); 2107 sm_load_security_info(sm_connection); 2108 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2109 break; 2110 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2111 sm_reset_setup(); 2112 sm_init_setup(sm_connection); 2113 sm_timeout_start(sm_connection); 2114 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2115 break; 2116 #endif 2117 2118 default: 2119 done = 0; 2120 break; 2121 } 2122 if (done){ 2123 sm_active_connection_handle = sm_connection->sm_handle; 2124 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); 2125 } 2126 } 2127 2128 // 2129 // active connection handling 2130 // 2131 2132 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2133 2134 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2135 if (!connection) { 2136 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2137 return; 2138 } 2139 2140 // assert that we could send a SM PDU - not needed for all of the following 2141 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2142 log_info("cannot send now, requesting can send now event"); 2143 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2144 return; 2145 } 2146 2147 // send keypress notifications 2148 if (setup->sm_keypress_notification){ 2149 int i; 2150 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2151 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2152 uint8_t action = 0; 2153 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2154 if (flags & (1<<i)){ 2155 int clear_flag = 1; 2156 switch (i){ 2157 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2158 case SM_KEYPRESS_PASSKEY_CLEARED: 2159 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2160 default: 2161 break; 2162 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2163 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2164 num_actions--; 2165 clear_flag = num_actions == 0; 2166 break; 2167 } 2168 if (clear_flag){ 2169 flags &= ~(1<<i); 2170 } 2171 action = i; 2172 break; 2173 } 2174 } 2175 setup->sm_keypress_notification = (num_actions << 5) | flags; 2176 2177 // send keypress notification 2178 uint8_t buffer[2]; 2179 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2180 buffer[1] = action; 2181 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2182 2183 // try 2184 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2185 return; 2186 } 2187 2188 int key_distribution_flags; 2189 UNUSED(key_distribution_flags); 2190 2191 log_info("sm_run: state %u", connection->sm_engine_state); 2192 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2193 log_info("sm_run // cannot send"); 2194 } 2195 switch (connection->sm_engine_state){ 2196 2197 // general 2198 case SM_GENERAL_SEND_PAIRING_FAILED: { 2199 uint8_t buffer[2]; 2200 buffer[0] = SM_CODE_PAIRING_FAILED; 2201 buffer[1] = setup->sm_pairing_failed_reason; 2202 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2203 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2204 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2205 sm_done_for_handle(connection->sm_handle); 2206 break; 2207 } 2208 2209 // responding state 2210 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2211 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2212 if (!sm_cmac_ready()) break; 2213 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2214 sm_sc_calculate_local_confirm(connection); 2215 break; 2216 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2217 if (!sm_cmac_ready()) break; 2218 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2219 sm_sc_calculate_remote_confirm(connection); 2220 break; 2221 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2222 if (!sm_cmac_ready()) break; 2223 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2224 sm_sc_calculate_f6_for_dhkey_check(connection); 2225 break; 2226 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2227 if (!sm_cmac_ready()) break; 2228 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2229 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2230 break; 2231 case SM_SC_W2_CALCULATE_F5_SALT: 2232 if (!sm_cmac_ready()) break; 2233 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2234 f5_calculate_salt(connection); 2235 break; 2236 case SM_SC_W2_CALCULATE_F5_MACKEY: 2237 if (!sm_cmac_ready()) break; 2238 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2239 f5_calculate_mackey(connection); 2240 break; 2241 case SM_SC_W2_CALCULATE_F5_LTK: 2242 if (!sm_cmac_ready()) break; 2243 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2244 f5_calculate_ltk(connection); 2245 break; 2246 case SM_SC_W2_CALCULATE_G2: 2247 if (!sm_cmac_ready()) break; 2248 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2249 g2_calculate(connection); 2250 break; 2251 case SM_SC_W2_CALCULATE_H6_ILK: 2252 if (!sm_cmac_ready()) break; 2253 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2254 h6_calculate_ilk(connection); 2255 break; 2256 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2257 if (!sm_cmac_ready()) break; 2258 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2259 h6_calculate_br_edr_link_key(connection); 2260 break; 2261 #endif 2262 2263 #ifdef ENABLE_LE_CENTRAL 2264 // initiator side 2265 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2266 sm_key_t peer_ltk_flipped; 2267 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2268 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2269 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2270 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2271 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2272 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2273 return; 2274 } 2275 2276 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2277 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2278 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2279 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2280 sm_timeout_reset(connection); 2281 break; 2282 #endif 2283 2284 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2285 2286 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2287 int trigger_user_response = 0; 2288 2289 uint8_t buffer[65]; 2290 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2291 // 2292 reverse_256(&ec_q[0], &buffer[1]); 2293 reverse_256(&ec_q[32], &buffer[33]); 2294 2295 #ifdef ENABLE_TESTING_SUPPORT 2296 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2297 log_info("testing_support: invalidating public key"); 2298 // flip single bit of public key coordinate 2299 buffer[1] ^= 1; 2300 } 2301 #endif 2302 2303 // stk generation method 2304 // passkey entry: notify app to show passkey or to request passkey 2305 switch (setup->sm_stk_generation_method){ 2306 case JUST_WORKS: 2307 case NUMERIC_COMPARISON: 2308 if (IS_RESPONDER(connection->sm_role)){ 2309 // responder 2310 sm_sc_start_calculating_local_confirm(connection); 2311 } else { 2312 // initiator 2313 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2314 } 2315 break; 2316 case PK_INIT_INPUT: 2317 case PK_RESP_INPUT: 2318 case PK_BOTH_INPUT: 2319 // use random TK for display 2320 memcpy(setup->sm_ra, setup->sm_tk, 16); 2321 memcpy(setup->sm_rb, setup->sm_tk, 16); 2322 setup->sm_passkey_bit = 0; 2323 2324 if (IS_RESPONDER(connection->sm_role)){ 2325 // responder 2326 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2327 } else { 2328 // initiator 2329 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2330 } 2331 trigger_user_response = 1; 2332 break; 2333 case OOB: 2334 if (IS_RESPONDER(connection->sm_role)){ 2335 // responder 2336 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2337 } else { 2338 // initiator 2339 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2340 } 2341 break; 2342 } 2343 2344 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2345 sm_timeout_reset(connection); 2346 2347 // trigger user response after sending pdu 2348 if (trigger_user_response){ 2349 sm_trigger_user_response(connection); 2350 } 2351 break; 2352 } 2353 case SM_SC_SEND_CONFIRMATION: { 2354 uint8_t buffer[17]; 2355 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2356 reverse_128(setup->sm_local_confirm, &buffer[1]); 2357 if (IS_RESPONDER(connection->sm_role)){ 2358 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2359 } else { 2360 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2361 } 2362 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2363 sm_timeout_reset(connection); 2364 break; 2365 } 2366 case SM_SC_SEND_PAIRING_RANDOM: { 2367 uint8_t buffer[17]; 2368 buffer[0] = SM_CODE_PAIRING_RANDOM; 2369 reverse_128(setup->sm_local_nonce, &buffer[1]); 2370 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2371 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2372 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2373 if (IS_RESPONDER(connection->sm_role)){ 2374 // responder 2375 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2376 } else { 2377 // initiator 2378 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2379 } 2380 } else { 2381 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2382 if (IS_RESPONDER(connection->sm_role)){ 2383 // responder 2384 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2385 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2386 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2387 } else { 2388 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2389 sm_sc_prepare_dhkey_check(connection); 2390 } 2391 } else { 2392 // initiator 2393 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2394 } 2395 } 2396 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2397 sm_timeout_reset(connection); 2398 break; 2399 } 2400 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2401 uint8_t buffer[17]; 2402 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2403 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2404 2405 if (IS_RESPONDER(connection->sm_role)){ 2406 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2407 } else { 2408 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2409 } 2410 2411 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2412 sm_timeout_reset(connection); 2413 break; 2414 } 2415 2416 #endif 2417 2418 #ifdef ENABLE_LE_PERIPHERAL 2419 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2420 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2421 2422 // start with initiator key dist flags 2423 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2424 2425 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2426 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2427 if (setup->sm_use_secure_connections){ 2428 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2429 } 2430 #endif 2431 // setup in response 2432 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); 2433 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); 2434 2435 // update key distribution after ENC was dropped 2436 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2437 2438 if (setup->sm_use_secure_connections){ 2439 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2440 } else { 2441 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2442 } 2443 2444 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2445 sm_timeout_reset(connection); 2446 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2447 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2448 sm_trigger_user_response(connection); 2449 } 2450 return; 2451 #endif 2452 2453 case SM_PH2_SEND_PAIRING_RANDOM: { 2454 uint8_t buffer[17]; 2455 buffer[0] = SM_CODE_PAIRING_RANDOM; 2456 reverse_128(setup->sm_local_random, &buffer[1]); 2457 if (IS_RESPONDER(connection->sm_role)){ 2458 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2459 } else { 2460 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2461 } 2462 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2463 sm_timeout_reset(connection); 2464 break; 2465 } 2466 2467 case SM_PH2_C1_GET_ENC_A: 2468 // already busy? 2469 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2470 // calculate confirm using aes128 engine - step 1 2471 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); 2472 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2473 sm_aes128_state = SM_AES128_ACTIVE; 2474 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2475 break; 2476 2477 case SM_PH2_C1_GET_ENC_C: 2478 // already busy? 2479 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2480 // calculate m_confirm using aes128 engine - step 1 2481 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); 2482 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2483 sm_aes128_state = SM_AES128_ACTIVE; 2484 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2485 break; 2486 2487 case SM_PH2_CALC_STK: 2488 // already busy? 2489 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2490 // calculate STK 2491 if (IS_RESPONDER(connection->sm_role)){ 2492 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2493 } else { 2494 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2495 } 2496 connection->sm_engine_state = SM_PH2_W4_STK; 2497 sm_aes128_state = SM_AES128_ACTIVE; 2498 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2499 break; 2500 2501 case SM_PH3_Y_GET_ENC: 2502 // already busy? 2503 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2504 // PH3B2 - calculate Y from - enc 2505 // Y = dm(DHK, Rand) 2506 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2507 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2508 sm_aes128_state = SM_AES128_ACTIVE; 2509 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); 2510 break; 2511 2512 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2513 uint8_t buffer[17]; 2514 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2515 reverse_128(setup->sm_local_confirm, &buffer[1]); 2516 if (IS_RESPONDER(connection->sm_role)){ 2517 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2518 } else { 2519 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2520 } 2521 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2522 sm_timeout_reset(connection); 2523 return; 2524 } 2525 #ifdef ENABLE_LE_PERIPHERAL 2526 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2527 sm_key_t stk_flipped; 2528 reverse_128(setup->sm_ltk, stk_flipped); 2529 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2530 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2531 return; 2532 } 2533 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2534 sm_key_t ltk_flipped; 2535 reverse_128(setup->sm_ltk, ltk_flipped); 2536 connection->sm_engine_state = SM_RESPONDER_IDLE; 2537 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2538 sm_done_for_handle(connection->sm_handle); 2539 return; 2540 } 2541 case SM_RESPONDER_PH4_Y_GET_ENC: 2542 // already busy? 2543 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2544 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2545 // Y = dm(DHK, Rand) 2546 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2547 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2548 sm_aes128_state = SM_AES128_ACTIVE; 2549 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); 2550 return; 2551 #endif 2552 #ifdef ENABLE_LE_CENTRAL 2553 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2554 sm_key_t stk_flipped; 2555 reverse_128(setup->sm_ltk, stk_flipped); 2556 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2557 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2558 return; 2559 } 2560 #endif 2561 2562 case SM_PH3_DISTRIBUTE_KEYS: 2563 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2564 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2565 uint8_t buffer[17]; 2566 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2567 reverse_128(setup->sm_ltk, &buffer[1]); 2568 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2569 sm_timeout_reset(connection); 2570 return; 2571 } 2572 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2573 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2574 uint8_t buffer[11]; 2575 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2576 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2577 reverse_64(setup->sm_local_rand, &buffer[3]); 2578 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2579 sm_timeout_reset(connection); 2580 return; 2581 } 2582 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2583 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2584 uint8_t buffer[17]; 2585 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2586 reverse_128(sm_persistent_irk, &buffer[1]); 2587 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2588 sm_timeout_reset(connection); 2589 return; 2590 } 2591 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2592 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2593 bd_addr_t local_address; 2594 uint8_t buffer[8]; 2595 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2596 switch (gap_random_address_get_mode()){ 2597 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2598 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2599 // public or static random 2600 gap_le_get_own_address(&buffer[1], local_address); 2601 break; 2602 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2603 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2604 // fallback to public 2605 gap_local_bd_addr(local_address); 2606 buffer[1] = 0; 2607 break; 2608 } 2609 reverse_bd_addr(local_address, &buffer[2]); 2610 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2611 sm_timeout_reset(connection); 2612 return; 2613 } 2614 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2615 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2616 2617 // hack to reproduce test runs 2618 if (test_use_fixed_local_csrk){ 2619 memset(setup->sm_local_csrk, 0xcc, 16); 2620 } 2621 2622 uint8_t buffer[17]; 2623 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2624 reverse_128(setup->sm_local_csrk, &buffer[1]); 2625 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2626 sm_timeout_reset(connection); 2627 return; 2628 } 2629 2630 // keys are sent 2631 if (IS_RESPONDER(connection->sm_role)){ 2632 // slave -> receive master keys if any 2633 if (sm_key_distribution_all_received(connection)){ 2634 sm_key_distribution_handle_all_received(connection); 2635 connection->sm_engine_state = SM_RESPONDER_IDLE; 2636 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2637 sm_done_for_handle(connection->sm_handle); 2638 } else { 2639 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2640 } 2641 } else { 2642 // master -> all done 2643 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2644 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2645 sm_done_for_handle(connection->sm_handle); 2646 } 2647 break; 2648 2649 default: 2650 break; 2651 } 2652 2653 // check again if active connection was released 2654 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2655 } 2656 } 2657 2658 // sm_aes128_state stays active 2659 static void sm_handle_encryption_result_enc_a(void *arg){ 2660 sm_connection_t * connection = (sm_connection_t*) arg; 2661 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2662 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); 2663 } 2664 2665 static void sm_handle_encryption_result_enc_b(void *arg){ 2666 sm_connection_t * connection = (sm_connection_t*) arg; 2667 sm_aes128_state = SM_AES128_IDLE; 2668 log_info_key("c1!", setup->sm_local_confirm); 2669 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2670 sm_run(); 2671 } 2672 2673 // sm_aes128_state stays active 2674 static void sm_handle_encryption_result_enc_c(void *arg){ 2675 sm_connection_t * connection = (sm_connection_t*) arg; 2676 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2677 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); 2678 } 2679 2680 static void sm_handle_encryption_result_enc_d(void * arg){ 2681 sm_connection_t * connection = (sm_connection_t*) arg; 2682 sm_aes128_state = SM_AES128_IDLE; 2683 log_info_key("c1!", sm_aes128_ciphertext); 2684 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2685 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2686 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2687 sm_run(); 2688 return; 2689 } 2690 if (IS_RESPONDER(connection->sm_role)){ 2691 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2692 sm_run(); 2693 } else { 2694 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2695 sm_aes128_state = SM_AES128_ACTIVE; 2696 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2697 } 2698 } 2699 2700 static void sm_handle_encryption_result_enc_stk(void *arg){ 2701 sm_connection_t * connection = (sm_connection_t*) arg; 2702 sm_aes128_state = SM_AES128_IDLE; 2703 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2704 log_info_key("stk", setup->sm_ltk); 2705 if (IS_RESPONDER(connection->sm_role)){ 2706 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2707 } else { 2708 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2709 } 2710 sm_run(); 2711 } 2712 2713 // sm_aes128_state stays active 2714 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2715 sm_connection_t * connection = (sm_connection_t*) arg; 2716 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2717 log_info_hex16("y", setup->sm_local_y); 2718 // PH3B3 - calculate EDIV 2719 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2720 log_info_hex16("ediv", setup->sm_local_ediv); 2721 // PH3B4 - calculate LTK - enc 2722 // LTK = d1(ER, DIV, 0)) 2723 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2724 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); 2725 } 2726 2727 #ifdef ENABLE_LE_PERIPHERAL 2728 // sm_aes128_state stays active 2729 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2730 sm_connection_t * connection = (sm_connection_t*) arg; 2731 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2732 log_info_hex16("y", setup->sm_local_y); 2733 2734 // PH3B3 - calculate DIV 2735 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2736 log_info_hex16("ediv", setup->sm_local_ediv); 2737 // PH3B4 - calculate LTK - enc 2738 // LTK = d1(ER, DIV, 0)) 2739 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2740 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); 2741 } 2742 #endif 2743 2744 // sm_aes128_state stays active 2745 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2746 sm_connection_t * connection = (sm_connection_t*) arg; 2747 log_info_key("ltk", setup->sm_ltk); 2748 // calc CSRK next 2749 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2750 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); 2751 } 2752 2753 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2754 sm_connection_t * connection = (sm_connection_t*) arg; 2755 sm_aes128_state = SM_AES128_IDLE; 2756 log_info_key("csrk", setup->sm_local_csrk); 2757 if (setup->sm_key_distribution_send_set){ 2758 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2759 } else { 2760 // no keys to send, just continue 2761 if (IS_RESPONDER(connection->sm_role)){ 2762 // slave -> receive master keys 2763 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2764 } else { 2765 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2766 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2767 } else { 2768 // master -> all done 2769 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2770 sm_done_for_handle(connection->sm_handle); 2771 } 2772 } 2773 } 2774 sm_run(); 2775 } 2776 2777 #ifdef ENABLE_LE_PERIPHERAL 2778 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2779 sm_connection_t * connection = (sm_connection_t*) arg; 2780 sm_aes128_state = SM_AES128_IDLE; 2781 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2782 log_info_key("ltk", setup->sm_ltk); 2783 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2784 sm_run(); 2785 } 2786 #endif 2787 2788 static void sm_handle_encryption_result_address_resolution(void *arg){ 2789 UNUSED(arg); 2790 sm_aes128_state = SM_AES128_IDLE; 2791 sm_address_resolution_ah_calculation_active = 0; 2792 // compare calulated address against connecting device 2793 uint8_t * hash = &sm_aes128_ciphertext[13]; 2794 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2795 log_info("LE Device Lookup: matched resolvable private address"); 2796 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2797 sm_run(); 2798 return; 2799 } 2800 // no match, try next 2801 sm_address_resolution_test++; 2802 sm_run(); 2803 } 2804 2805 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2806 UNUSED(arg); 2807 sm_aes128_state = SM_AES128_IDLE; 2808 log_info_key("irk", sm_persistent_irk); 2809 dkg_state = DKG_CALC_DHK; 2810 sm_run(); 2811 } 2812 2813 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2814 UNUSED(arg); 2815 sm_aes128_state = SM_AES128_IDLE; 2816 log_info_key("dhk", sm_persistent_dhk); 2817 dkg_state = DKG_READY; 2818 sm_run(); 2819 } 2820 2821 static void sm_handle_encryption_result_rau(void *arg){ 2822 UNUSED(arg); 2823 sm_aes128_state = SM_AES128_IDLE; 2824 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2825 rau_state = RAU_SET_ADDRESS; 2826 sm_run(); 2827 } 2828 2829 static void sm_handle_random_result_rau(void * arg){ 2830 UNUSED(arg); 2831 // non-resolvable vs. resolvable 2832 switch (gap_random_adress_type){ 2833 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2834 // resolvable: use random as prand and calc address hash 2835 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2836 sm_random_address[0] &= 0x3f; 2837 sm_random_address[0] |= 0x40; 2838 rau_state = RAU_GET_ENC; 2839 break; 2840 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2841 default: 2842 // "The two most significant bits of the address shall be equal to ‘0’"" 2843 sm_random_address[0] &= 0x3f; 2844 rau_state = RAU_SET_ADDRESS; 2845 break; 2846 } 2847 sm_run(); 2848 } 2849 2850 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2851 static void sm_handle_random_result_sc_get_random(void * arg){ 2852 sm_connection_t * connection = (sm_connection_t*) arg; 2853 2854 // OOB 2855 if (setup->sm_stk_generation_method == OOB){ 2856 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2857 sm_run(); 2858 return; 2859 } 2860 2861 // initiator & jw/nc -> send pairing random 2862 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2863 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2864 } else { 2865 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2866 } 2867 sm_run(); 2868 } 2869 #endif 2870 2871 static void sm_handle_random_result_ph2_random(void * arg){ 2872 sm_connection_t * connection = (sm_connection_t*) arg; 2873 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2874 sm_run(); 2875 } 2876 2877 static void sm_handle_random_result_ph2_tk(void * arg){ 2878 sm_connection_t * connection = (sm_connection_t*) arg; 2879 sm_reset_tk(); 2880 uint32_t tk; 2881 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2882 // map random to 0-999999 without speding much cycles on a modulus operation 2883 tk = little_endian_read_32(sm_random_data,0); 2884 tk = tk & 0xfffff; // 1048575 2885 if (tk >= 999999){ 2886 tk = tk - 999999; 2887 } 2888 } else { 2889 // override with pre-defined passkey 2890 tk = sm_fixed_passkey_in_display_role; 2891 } 2892 big_endian_store_32(setup->sm_tk, 12, tk); 2893 if (IS_RESPONDER(connection->sm_role)){ 2894 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2895 } else { 2896 if (setup->sm_use_secure_connections){ 2897 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2898 } else { 2899 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2900 sm_trigger_user_response(connection); 2901 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2902 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2903 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2904 } 2905 } 2906 } 2907 sm_run(); 2908 } 2909 2910 static void sm_handle_random_result_ph3_div(void * arg){ 2911 sm_connection_t * connection = (sm_connection_t*) arg; 2912 // use 16 bit from random value as div 2913 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2914 log_info_hex16("div", setup->sm_local_div); 2915 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2916 sm_run(); 2917 } 2918 2919 static void sm_handle_random_result_ph3_random(void * arg){ 2920 sm_connection_t * connection = (sm_connection_t*) arg; 2921 reverse_64(sm_random_data, setup->sm_local_rand); 2922 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2923 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2924 // no db for authenticated flag hack: store flag in bit 4 of LSB 2925 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2926 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2927 } 2928 static void sm_validate_er_ir(void){ 2929 // warn about default ER/IR 2930 int warning = 0; 2931 if (sm_ir_is_default()){ 2932 warning = 1; 2933 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 2934 } 2935 if (sm_er_is_default()){ 2936 warning = 1; 2937 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 2938 } 2939 if (warning) { 2940 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 2941 } 2942 } 2943 2944 static void sm_handle_random_result_ir(void *arg){ 2945 sm_persistent_keys_random_active = 0; 2946 if (arg){ 2947 // key generated, store in tlv 2948 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2949 log_info("Generated IR key. Store in TLV status: %d", status); 2950 } 2951 log_info_key("IR", sm_persistent_ir); 2952 dkg_state = DKG_CALC_IRK; 2953 sm_run(); 2954 } 2955 2956 static void sm_handle_random_result_er(void *arg){ 2957 sm_persistent_keys_random_active = 0; 2958 if (arg){ 2959 // key generated, store in tlv 2960 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2961 log_info("Generated ER key. Store in TLV status: %d", status); 2962 } 2963 log_info_key("ER", sm_persistent_er); 2964 2965 // try load ir 2966 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2967 if (key_size == 16){ 2968 // ok, let's continue 2969 log_info("IR from TLV"); 2970 sm_handle_random_result_ir( NULL ); 2971 } else { 2972 // invalid, generate new random one 2973 sm_persistent_keys_random_active = 1; 2974 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 2975 } 2976 } 2977 2978 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2979 2980 UNUSED(channel); // ok: there is no channel 2981 UNUSED(size); // ok: fixed format HCI events 2982 2983 sm_connection_t * sm_conn; 2984 hci_con_handle_t con_handle; 2985 2986 switch (packet_type) { 2987 2988 case HCI_EVENT_PACKET: 2989 switch (hci_event_packet_get_type(packet)) { 2990 2991 case BTSTACK_EVENT_STATE: 2992 // bt stack activated, get started 2993 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2994 log_info("HCI Working!"); 2995 2996 // setup IR/ER with TLV 2997 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 2998 if (sm_tlv_impl){ 2999 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3000 if (key_size == 16){ 3001 // ok, let's continue 3002 log_info("ER from TLV"); 3003 sm_handle_random_result_er( NULL ); 3004 } else { 3005 // invalid, generate random one 3006 sm_persistent_keys_random_active = 1; 3007 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3008 } 3009 } else { 3010 sm_validate_er_ir(); 3011 dkg_state = DKG_CALC_IRK; 3012 } 3013 } 3014 break; 3015 3016 case HCI_EVENT_LE_META: 3017 switch (packet[2]) { 3018 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3019 3020 log_info("sm: connected"); 3021 3022 if (packet[3]) return; // connection failed 3023 3024 con_handle = little_endian_read_16(packet, 4); 3025 sm_conn = sm_get_connection_for_handle(con_handle); 3026 if (!sm_conn) break; 3027 3028 sm_conn->sm_handle = con_handle; 3029 sm_conn->sm_role = packet[6]; 3030 sm_conn->sm_peer_addr_type = packet[7]; 3031 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3032 3033 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3034 3035 // reset security properties 3036 sm_conn->sm_connection_encrypted = 0; 3037 sm_conn->sm_connection_authenticated = 0; 3038 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3039 sm_conn->sm_le_db_index = -1; 3040 3041 // prepare CSRK lookup (does not involve setup) 3042 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3043 3044 // just connected -> everything else happens in sm_run() 3045 if (IS_RESPONDER(sm_conn->sm_role)){ 3046 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3047 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3048 if (sm_slave_request_security) { 3049 // request security if requested by app 3050 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3051 } else { 3052 // otherwise, wait for pairing request 3053 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3054 } 3055 } 3056 break; 3057 } else { 3058 // master 3059 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3060 } 3061 break; 3062 3063 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3064 con_handle = little_endian_read_16(packet, 3); 3065 sm_conn = sm_get_connection_for_handle(con_handle); 3066 if (!sm_conn) break; 3067 3068 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3069 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3070 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3071 break; 3072 } 3073 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3074 // PH2 SEND LTK as we need to exchange keys in PH3 3075 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3076 break; 3077 } 3078 3079 // store rand and ediv 3080 reverse_64(&packet[5], sm_conn->sm_local_rand); 3081 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3082 3083 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3084 // potentially stored LTK is from the master 3085 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3086 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3087 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3088 break; 3089 } 3090 // additionally check if remote is in LE Device DB if requested 3091 switch(sm_conn->sm_irk_lookup_state){ 3092 case IRK_LOOKUP_FAILED: 3093 log_info("LTK Request: device not in device db"); 3094 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3095 break; 3096 case IRK_LOOKUP_SUCCEEDED: 3097 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3098 break; 3099 default: 3100 // wait for irk look doen 3101 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3102 break; 3103 } 3104 break; 3105 } 3106 3107 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3108 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3109 #else 3110 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3111 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3112 #endif 3113 break; 3114 3115 default: 3116 break; 3117 } 3118 break; 3119 3120 case HCI_EVENT_ENCRYPTION_CHANGE: 3121 con_handle = little_endian_read_16(packet, 3); 3122 sm_conn = sm_get_connection_for_handle(con_handle); 3123 if (!sm_conn) break; 3124 3125 sm_conn->sm_connection_encrypted = packet[5]; 3126 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3127 sm_conn->sm_actual_encryption_key_size); 3128 log_info("event handler, state %u", sm_conn->sm_engine_state); 3129 3130 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3131 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3132 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3133 // notify client, if pairing was requested before 3134 if (sm_conn->sm_pairing_requested){ 3135 sm_conn->sm_pairing_requested = 0; 3136 if (sm_conn->sm_connection_encrypted){ 3137 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3138 } else { 3139 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3140 } 3141 } 3142 sm_done_for_handle(sm_conn->sm_handle); 3143 break; 3144 } 3145 3146 if (!sm_conn->sm_connection_encrypted) break; 3147 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3148 3149 // continue pairing 3150 switch (sm_conn->sm_engine_state){ 3151 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3152 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3153 sm_done_for_handle(sm_conn->sm_handle); 3154 break; 3155 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3156 if (IS_RESPONDER(sm_conn->sm_role)){ 3157 // slave 3158 if (setup->sm_use_secure_connections){ 3159 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3160 } else { 3161 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3162 } 3163 } else { 3164 // master 3165 if (sm_key_distribution_all_received(sm_conn)){ 3166 // skip receiving keys as there are none 3167 sm_key_distribution_handle_all_received(sm_conn); 3168 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3169 } else { 3170 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3171 } 3172 } 3173 break; 3174 default: 3175 break; 3176 } 3177 break; 3178 3179 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3180 con_handle = little_endian_read_16(packet, 3); 3181 sm_conn = sm_get_connection_for_handle(con_handle); 3182 if (!sm_conn) break; 3183 3184 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3185 log_info("event handler, state %u", sm_conn->sm_engine_state); 3186 // continue if part of initial pairing 3187 switch (sm_conn->sm_engine_state){ 3188 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3189 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3190 sm_done_for_handle(sm_conn->sm_handle); 3191 break; 3192 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3193 if (IS_RESPONDER(sm_conn->sm_role)){ 3194 // slave 3195 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3196 } else { 3197 // master 3198 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3199 } 3200 break; 3201 default: 3202 break; 3203 } 3204 break; 3205 3206 3207 case HCI_EVENT_DISCONNECTION_COMPLETE: 3208 con_handle = little_endian_read_16(packet, 3); 3209 sm_done_for_handle(con_handle); 3210 sm_conn = sm_get_connection_for_handle(con_handle); 3211 if (!sm_conn) break; 3212 3213 // delete stored bonding on disconnect with authentication failure in ph0 3214 if (sm_conn->sm_role == 0 3215 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3216 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3217 le_device_db_remove(sm_conn->sm_le_db_index); 3218 } 3219 3220 // pairing failed, if it was ongoing 3221 switch (sm_conn->sm_engine_state){ 3222 case SM_GENERAL_IDLE: 3223 case SM_INITIATOR_CONNECTED: 3224 case SM_RESPONDER_IDLE: 3225 break; 3226 default: 3227 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3228 break; 3229 } 3230 3231 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3232 sm_conn->sm_handle = 0; 3233 break; 3234 3235 case HCI_EVENT_COMMAND_COMPLETE: 3236 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3237 // set local addr for le device db 3238 bd_addr_t addr; 3239 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3240 le_device_db_set_local_bd_addr(addr); 3241 } 3242 break; 3243 default: 3244 break; 3245 } 3246 break; 3247 default: 3248 break; 3249 } 3250 3251 sm_run(); 3252 } 3253 3254 static inline int sm_calc_actual_encryption_key_size(int other){ 3255 if (other < sm_min_encryption_key_size) return 0; 3256 if (other < sm_max_encryption_key_size) return other; 3257 return sm_max_encryption_key_size; 3258 } 3259 3260 3261 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3262 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3263 switch (method){ 3264 case JUST_WORKS: 3265 case NUMERIC_COMPARISON: 3266 return 1; 3267 default: 3268 return 0; 3269 } 3270 } 3271 // responder 3272 3273 static int sm_passkey_used(stk_generation_method_t method){ 3274 switch (method){ 3275 case PK_RESP_INPUT: 3276 return 1; 3277 default: 3278 return 0; 3279 } 3280 } 3281 3282 static int sm_passkey_entry(stk_generation_method_t method){ 3283 switch (method){ 3284 case PK_RESP_INPUT: 3285 case PK_INIT_INPUT: 3286 case PK_BOTH_INPUT: 3287 return 1; 3288 default: 3289 return 0; 3290 } 3291 } 3292 3293 #endif 3294 3295 /** 3296 * @return ok 3297 */ 3298 static int sm_validate_stk_generation_method(void){ 3299 // check if STK generation method is acceptable by client 3300 switch (setup->sm_stk_generation_method){ 3301 case JUST_WORKS: 3302 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3303 case PK_RESP_INPUT: 3304 case PK_INIT_INPUT: 3305 case PK_BOTH_INPUT: 3306 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3307 case OOB: 3308 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3309 case NUMERIC_COMPARISON: 3310 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3311 default: 3312 return 0; 3313 } 3314 } 3315 3316 // size of complete sm_pdu used to validate input 3317 static const uint8_t sm_pdu_size[] = { 3318 0, // 0x00 invalid opcode 3319 7, // 0x01 pairing request 3320 7, // 0x02 pairing response 3321 17, // 0x03 pairing confirm 3322 17, // 0x04 pairing random 3323 2, // 0x05 pairing failed 3324 17, // 0x06 encryption information 3325 11, // 0x07 master identification 3326 17, // 0x08 identification information 3327 8, // 0x09 identify address information 3328 17, // 0x0a signing information 3329 2, // 0x0b security request 3330 65, // 0x0c pairing public key 3331 17, // 0x0d pairing dhk check 3332 2, // 0x0e keypress notification 3333 }; 3334 3335 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3336 3337 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3338 sm_run(); 3339 } 3340 3341 if (packet_type != SM_DATA_PACKET) return; 3342 if (size == 0) return; 3343 3344 uint8_t sm_pdu_code = packet[0]; 3345 3346 // validate pdu size 3347 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3348 if (sm_pdu_size[sm_pdu_code] != size) return; 3349 3350 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3351 if (!sm_conn) return; 3352 3353 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3354 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3355 sm_done_for_handle(con_handle); 3356 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3357 return; 3358 } 3359 3360 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3361 3362 int err; 3363 UNUSED(err); 3364 3365 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3366 uint8_t buffer[5]; 3367 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3368 buffer[1] = 3; 3369 little_endian_store_16(buffer, 2, con_handle); 3370 buffer[4] = packet[1]; 3371 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3372 return; 3373 } 3374 3375 switch (sm_conn->sm_engine_state){ 3376 3377 // a sm timeout requries a new physical connection 3378 case SM_GENERAL_TIMEOUT: 3379 return; 3380 3381 #ifdef ENABLE_LE_CENTRAL 3382 3383 // Initiator 3384 case SM_INITIATOR_CONNECTED: 3385 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3386 sm_pdu_received_in_wrong_state(sm_conn); 3387 break; 3388 } 3389 3390 // IRK complete? 3391 switch (sm_conn->sm_irk_lookup_state){ 3392 case IRK_LOOKUP_FAILED: 3393 case IRK_LOOKUP_SUCCEEDED: 3394 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3395 break; 3396 default: 3397 break; 3398 } 3399 3400 // otherwise, store security request 3401 sm_conn->sm_security_request_received = 1; 3402 break; 3403 3404 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3405 // Core 5, Vol 3, Part H, 2.4.6: 3406 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3407 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3408 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3409 log_info("Ignoring Security Request"); 3410 break; 3411 } 3412 3413 // all other pdus are incorrect 3414 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3415 sm_pdu_received_in_wrong_state(sm_conn); 3416 break; 3417 } 3418 3419 // store pairing request 3420 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3421 err = sm_stk_generation_init(sm_conn); 3422 3423 #ifdef ENABLE_TESTING_SUPPORT 3424 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3425 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3426 err = test_pairing_failure; 3427 } 3428 #endif 3429 3430 if (err){ 3431 setup->sm_pairing_failed_reason = err; 3432 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3433 break; 3434 } 3435 3436 // generate random number first, if we need to show passkey 3437 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3438 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3439 break; 3440 } 3441 3442 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3443 if (setup->sm_use_secure_connections){ 3444 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3445 if (setup->sm_stk_generation_method == JUST_WORKS){ 3446 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3447 sm_trigger_user_response(sm_conn); 3448 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3449 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3450 } 3451 } else { 3452 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3453 } 3454 break; 3455 } 3456 #endif 3457 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3458 sm_trigger_user_response(sm_conn); 3459 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3460 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3461 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3462 } 3463 break; 3464 3465 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3466 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3467 sm_pdu_received_in_wrong_state(sm_conn); 3468 break; 3469 } 3470 3471 // store s_confirm 3472 reverse_128(&packet[1], setup->sm_peer_confirm); 3473 3474 #ifdef ENABLE_TESTING_SUPPORT 3475 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3476 log_info("testing_support: reset confirm value"); 3477 memset(setup->sm_peer_confirm, 0, 16); 3478 } 3479 #endif 3480 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3481 break; 3482 3483 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3484 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3485 sm_pdu_received_in_wrong_state(sm_conn); 3486 break;; 3487 } 3488 3489 // received random value 3490 reverse_128(&packet[1], setup->sm_peer_random); 3491 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3492 break; 3493 #endif 3494 3495 #ifdef ENABLE_LE_PERIPHERAL 3496 // Responder 3497 case SM_RESPONDER_IDLE: 3498 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3499 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3500 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3501 sm_pdu_received_in_wrong_state(sm_conn); 3502 break;; 3503 } 3504 3505 // store pairing request 3506 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3507 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3508 break; 3509 #endif 3510 3511 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3512 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3513 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3514 sm_pdu_received_in_wrong_state(sm_conn); 3515 break; 3516 } 3517 3518 // store public key for DH Key calculation 3519 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3520 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3521 3522 // validate public key 3523 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3524 if (err){ 3525 log_error("sm: peer public key invalid %x", err); 3526 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3527 break; 3528 } 3529 3530 // start calculating dhkey 3531 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3532 3533 3534 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3535 if (IS_RESPONDER(sm_conn->sm_role)){ 3536 // responder 3537 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3538 } else { 3539 // initiator 3540 // stk generation method 3541 // passkey entry: notify app to show passkey or to request passkey 3542 switch (setup->sm_stk_generation_method){ 3543 case JUST_WORKS: 3544 case NUMERIC_COMPARISON: 3545 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3546 break; 3547 case PK_RESP_INPUT: 3548 sm_sc_start_calculating_local_confirm(sm_conn); 3549 break; 3550 case PK_INIT_INPUT: 3551 case PK_BOTH_INPUT: 3552 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3553 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3554 break; 3555 } 3556 sm_sc_start_calculating_local_confirm(sm_conn); 3557 break; 3558 case OOB: 3559 // generate Nx 3560 log_info("Generate Na"); 3561 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3562 break; 3563 } 3564 } 3565 break; 3566 3567 case SM_SC_W4_CONFIRMATION: 3568 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3569 sm_pdu_received_in_wrong_state(sm_conn); 3570 break; 3571 } 3572 // received confirm value 3573 reverse_128(&packet[1], setup->sm_peer_confirm); 3574 3575 #ifdef ENABLE_TESTING_SUPPORT 3576 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3577 log_info("testing_support: reset confirm value"); 3578 memset(setup->sm_peer_confirm, 0, 16); 3579 } 3580 #endif 3581 if (IS_RESPONDER(sm_conn->sm_role)){ 3582 // responder 3583 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3584 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3585 // still waiting for passkey 3586 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3587 break; 3588 } 3589 } 3590 sm_sc_start_calculating_local_confirm(sm_conn); 3591 } else { 3592 // initiator 3593 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3594 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3595 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3596 } else { 3597 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3598 } 3599 } 3600 break; 3601 3602 case SM_SC_W4_PAIRING_RANDOM: 3603 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3604 sm_pdu_received_in_wrong_state(sm_conn); 3605 break; 3606 } 3607 3608 // received random value 3609 reverse_128(&packet[1], setup->sm_peer_nonce); 3610 3611 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3612 // only check for JUST WORK/NC in initiator role OR passkey entry 3613 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3614 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3615 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3616 break; 3617 } 3618 3619 // OOB 3620 if (setup->sm_stk_generation_method == OOB){ 3621 3622 // setup local random, set to zero if remote did not receive our data 3623 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3624 if (IS_RESPONDER(sm_conn->sm_role)){ 3625 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3626 log_info("Reset rb as A does not have OOB data"); 3627 memset(setup->sm_rb, 0, 16); 3628 } else { 3629 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3630 log_info("Use stored rb"); 3631 log_info_hexdump(setup->sm_rb, 16); 3632 } 3633 } else { 3634 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3635 log_info("Reset ra as B does not have OOB data"); 3636 memset(setup->sm_ra, 0, 16); 3637 } else { 3638 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3639 log_info("Use stored ra"); 3640 log_info_hexdump(setup->sm_ra, 16); 3641 } 3642 } 3643 3644 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3645 if (setup->sm_have_oob_data){ 3646 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3647 break; 3648 } 3649 } 3650 3651 // TODO: we only get here for Responder role with JW/NC 3652 sm_sc_state_after_receiving_random(sm_conn); 3653 break; 3654 3655 case SM_SC_W2_CALCULATE_G2: 3656 case SM_SC_W4_CALCULATE_G2: 3657 case SM_SC_W4_CALCULATE_DHKEY: 3658 case SM_SC_W2_CALCULATE_F5_SALT: 3659 case SM_SC_W4_CALCULATE_F5_SALT: 3660 case SM_SC_W2_CALCULATE_F5_MACKEY: 3661 case SM_SC_W4_CALCULATE_F5_MACKEY: 3662 case SM_SC_W2_CALCULATE_F5_LTK: 3663 case SM_SC_W4_CALCULATE_F5_LTK: 3664 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3665 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3666 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3667 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3668 sm_pdu_received_in_wrong_state(sm_conn); 3669 break; 3670 } 3671 // store DHKey Check 3672 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3673 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3674 3675 // have we been only waiting for dhkey check command? 3676 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3677 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3678 } 3679 break; 3680 #endif 3681 3682 #ifdef ENABLE_LE_PERIPHERAL 3683 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3684 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3685 sm_pdu_received_in_wrong_state(sm_conn); 3686 break; 3687 } 3688 3689 // received confirm value 3690 reverse_128(&packet[1], setup->sm_peer_confirm); 3691 3692 #ifdef ENABLE_TESTING_SUPPORT 3693 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3694 log_info("testing_support: reset confirm value"); 3695 memset(setup->sm_peer_confirm, 0, 16); 3696 } 3697 #endif 3698 // notify client to hide shown passkey 3699 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3700 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3701 } 3702 3703 // handle user cancel pairing? 3704 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3705 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3706 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3707 break; 3708 } 3709 3710 // wait for user action? 3711 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3712 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3713 break; 3714 } 3715 3716 // calculate and send local_confirm 3717 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3718 break; 3719 3720 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3721 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3722 sm_pdu_received_in_wrong_state(sm_conn); 3723 break;; 3724 } 3725 3726 // received random value 3727 reverse_128(&packet[1], setup->sm_peer_random); 3728 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3729 break; 3730 #endif 3731 3732 case SM_PH3_RECEIVE_KEYS: 3733 switch(sm_pdu_code){ 3734 case SM_CODE_ENCRYPTION_INFORMATION: 3735 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3736 reverse_128(&packet[1], setup->sm_peer_ltk); 3737 break; 3738 3739 case SM_CODE_MASTER_IDENTIFICATION: 3740 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3741 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3742 reverse_64(&packet[3], setup->sm_peer_rand); 3743 break; 3744 3745 case SM_CODE_IDENTITY_INFORMATION: 3746 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3747 reverse_128(&packet[1], setup->sm_peer_irk); 3748 break; 3749 3750 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3751 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3752 setup->sm_peer_addr_type = packet[1]; 3753 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3754 break; 3755 3756 case SM_CODE_SIGNING_INFORMATION: 3757 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3758 reverse_128(&packet[1], setup->sm_peer_csrk); 3759 break; 3760 default: 3761 // Unexpected PDU 3762 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3763 break; 3764 } 3765 // done with key distribution? 3766 if (sm_key_distribution_all_received(sm_conn)){ 3767 3768 sm_key_distribution_handle_all_received(sm_conn); 3769 3770 if (IS_RESPONDER(sm_conn->sm_role)){ 3771 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3772 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3773 } else { 3774 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3775 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3776 sm_done_for_handle(sm_conn->sm_handle); 3777 } 3778 } else { 3779 if (setup->sm_use_secure_connections){ 3780 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3781 } else { 3782 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3783 } 3784 } 3785 } 3786 break; 3787 default: 3788 // Unexpected PDU 3789 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3790 break; 3791 } 3792 3793 // try to send preparared packet 3794 sm_run(); 3795 } 3796 3797 // Security Manager Client API 3798 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3799 sm_get_oob_data = get_oob_data_callback; 3800 } 3801 3802 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)){ 3803 sm_get_sc_oob_data = get_sc_oob_data_callback; 3804 } 3805 3806 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3807 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3808 } 3809 3810 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3811 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3812 } 3813 3814 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3815 sm_min_encryption_key_size = min_size; 3816 sm_max_encryption_key_size = max_size; 3817 } 3818 3819 void sm_set_authentication_requirements(uint8_t auth_req){ 3820 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3821 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3822 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3823 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3824 } 3825 #endif 3826 sm_auth_req = auth_req; 3827 } 3828 3829 void sm_set_io_capabilities(io_capability_t io_capability){ 3830 sm_io_capabilities = io_capability; 3831 } 3832 3833 #ifdef ENABLE_LE_PERIPHERAL 3834 void sm_set_request_security(int enable){ 3835 sm_slave_request_security = enable; 3836 } 3837 #endif 3838 3839 void sm_set_er(sm_key_t er){ 3840 memcpy(sm_persistent_er, er, 16); 3841 } 3842 3843 void sm_set_ir(sm_key_t ir){ 3844 memcpy(sm_persistent_ir, ir, 16); 3845 } 3846 3847 // Testing support only 3848 void sm_test_set_irk(sm_key_t irk){ 3849 memcpy(sm_persistent_irk, irk, 16); 3850 dkg_state = DKG_CALC_DHK; 3851 } 3852 3853 void sm_test_use_fixed_local_csrk(void){ 3854 test_use_fixed_local_csrk = 1; 3855 } 3856 3857 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3858 static void sm_ec_generated(void * arg){ 3859 UNUSED(arg); 3860 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3861 // trigger pairing if pending for ec key 3862 sm_run(); 3863 } 3864 static void sm_ec_generate_new_key(void){ 3865 log_info("sm: generate new ec key"); 3866 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3867 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3868 } 3869 #endif 3870 3871 #ifdef ENABLE_TESTING_SUPPORT 3872 void sm_test_set_pairing_failure(int reason){ 3873 test_pairing_failure = reason; 3874 } 3875 #endif 3876 3877 void sm_init(void){ 3878 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3879 sm_er_ir_set_default(); 3880 3881 // defaults 3882 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3883 | SM_STK_GENERATION_METHOD_OOB 3884 | SM_STK_GENERATION_METHOD_PASSKEY 3885 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3886 3887 sm_max_encryption_key_size = 16; 3888 sm_min_encryption_key_size = 7; 3889 3890 sm_fixed_passkey_in_display_role = 0xffffffff; 3891 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3892 3893 #ifdef USE_CMAC_ENGINE 3894 sm_cmac_active = 0; 3895 #endif 3896 dkg_state = DKG_W4_WORKING; 3897 rau_state = RAU_IDLE; 3898 sm_aes128_state = SM_AES128_IDLE; 3899 sm_address_resolution_test = -1; // no private address to resolve yet 3900 sm_address_resolution_ah_calculation_active = 0; 3901 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3902 sm_address_resolution_general_queue = NULL; 3903 3904 gap_random_adress_update_period = 15 * 60 * 1000L; 3905 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3906 3907 test_use_fixed_local_csrk = 0; 3908 3909 // register for HCI Events from HCI 3910 hci_event_callback_registration.callback = &sm_event_packet_handler; 3911 hci_add_event_handler(&hci_event_callback_registration); 3912 3913 // 3914 btstack_crypto_init(); 3915 3916 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3917 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3918 3919 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3920 sm_ec_generate_new_key(); 3921 #endif 3922 } 3923 3924 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3925 sm_fixed_passkey_in_display_role = passkey; 3926 } 3927 3928 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3929 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3930 } 3931 3932 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3933 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3934 if (!hci_con) return NULL; 3935 return &hci_con->sm_connection; 3936 } 3937 3938 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3939 switch (sm_conn->sm_engine_state){ 3940 case SM_GENERAL_IDLE: 3941 case SM_RESPONDER_IDLE: 3942 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3943 sm_run(); 3944 break; 3945 default: 3946 break; 3947 } 3948 } 3949 3950 /** 3951 * @brief Trigger Security Request 3952 */ 3953 void sm_send_security_request(hci_con_handle_t con_handle){ 3954 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3955 if (!sm_conn) return; 3956 sm_send_security_request_for_connection(sm_conn); 3957 } 3958 3959 // request pairing 3960 void sm_request_pairing(hci_con_handle_t con_handle){ 3961 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3962 if (!sm_conn) return; // wrong connection 3963 3964 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3965 if (IS_RESPONDER(sm_conn->sm_role)){ 3966 sm_send_security_request_for_connection(sm_conn); 3967 } else { 3968 // used as a trigger to start central/master/initiator security procedures 3969 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3970 uint8_t ltk[16]; 3971 switch (sm_conn->sm_irk_lookup_state){ 3972 case IRK_LOOKUP_SUCCEEDED: 3973 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 3974 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3975 log_info("have ltk %u", !sm_is_null_key(ltk)); 3976 // trigger 'pairing complete' event on encryption change 3977 sm_conn->sm_pairing_requested = 1; 3978 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3979 break; 3980 #endif 3981 /* explicit fall-through */ 3982 3983 case IRK_LOOKUP_FAILED: 3984 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3985 break; 3986 default: 3987 log_info("irk lookup pending"); 3988 sm_conn->sm_pairing_requested = 1; 3989 break; 3990 } 3991 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3992 sm_conn->sm_pairing_requested = 1; 3993 } 3994 } 3995 sm_run(); 3996 } 3997 3998 // called by client app on authorization request 3999 void sm_authorization_decline(hci_con_handle_t con_handle){ 4000 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4001 if (!sm_conn) return; // wrong connection 4002 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4003 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4004 } 4005 4006 void sm_authorization_grant(hci_con_handle_t con_handle){ 4007 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4008 if (!sm_conn) return; // wrong connection 4009 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4010 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4011 } 4012 4013 // GAP Bonding API 4014 4015 void sm_bonding_decline(hci_con_handle_t con_handle){ 4016 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4017 if (!sm_conn) return; // wrong connection 4018 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4019 log_info("decline, state %u", sm_conn->sm_engine_state); 4020 switch(sm_conn->sm_engine_state){ 4021 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4022 case SM_SC_W4_USER_RESPONSE: 4023 case SM_SC_W4_CONFIRMATION: 4024 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4025 #endif 4026 case SM_PH1_W4_USER_RESPONSE: 4027 switch (setup->sm_stk_generation_method){ 4028 case PK_RESP_INPUT: 4029 case PK_INIT_INPUT: 4030 case PK_BOTH_INPUT: 4031 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4032 break; 4033 case NUMERIC_COMPARISON: 4034 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4035 break; 4036 case JUST_WORKS: 4037 case OOB: 4038 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4039 break; 4040 } 4041 break; 4042 default: 4043 break; 4044 } 4045 sm_run(); 4046 } 4047 4048 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4049 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4050 if (!sm_conn) return; // wrong connection 4051 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4052 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4053 if (setup->sm_use_secure_connections){ 4054 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4055 } else { 4056 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4057 } 4058 } 4059 4060 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4061 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4062 sm_sc_prepare_dhkey_check(sm_conn); 4063 } 4064 #endif 4065 4066 sm_run(); 4067 } 4068 4069 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4070 // for now, it's the same 4071 sm_just_works_confirm(con_handle); 4072 } 4073 4074 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4075 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4076 if (!sm_conn) return; // wrong connection 4077 sm_reset_tk(); 4078 big_endian_store_32(setup->sm_tk, 12, passkey); 4079 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4080 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4081 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4082 } 4083 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4084 memcpy(setup->sm_ra, setup->sm_tk, 16); 4085 memcpy(setup->sm_rb, setup->sm_tk, 16); 4086 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4087 sm_sc_start_calculating_local_confirm(sm_conn); 4088 } 4089 #endif 4090 sm_run(); 4091 } 4092 4093 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4094 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4095 if (!sm_conn) return; // wrong connection 4096 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4097 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4098 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4099 switch (action){ 4100 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4101 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4102 flags |= (1 << action); 4103 break; 4104 case SM_KEYPRESS_PASSKEY_CLEARED: 4105 // clear counter, keypress & erased flags + set passkey cleared 4106 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4107 break; 4108 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4109 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4110 // erase actions queued 4111 num_actions--; 4112 if (num_actions == 0){ 4113 // clear counter, keypress & erased flags 4114 flags &= 0x19; 4115 } 4116 break; 4117 } 4118 num_actions++; 4119 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4120 break; 4121 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4122 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4123 // enter actions queued 4124 num_actions--; 4125 if (num_actions == 0){ 4126 // clear counter, keypress & erased flags 4127 flags &= 0x19; 4128 } 4129 break; 4130 } 4131 num_actions++; 4132 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4133 break; 4134 default: 4135 break; 4136 } 4137 setup->sm_keypress_notification = (num_actions << 5) | flags; 4138 sm_run(); 4139 } 4140 4141 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4142 static void sm_handle_random_result_oob(void * arg){ 4143 UNUSED(arg); 4144 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4145 sm_run(); 4146 } 4147 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4148 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4149 sm_sc_oob_callback = callback; 4150 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4151 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4152 return 0; 4153 } 4154 #endif 4155 4156 /** 4157 * @brief Identify device in LE Device DB 4158 * @param handle 4159 * @returns index from le_device_db or -1 if not found/identified 4160 */ 4161 int sm_le_device_index(hci_con_handle_t con_handle ){ 4162 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4163 if (!sm_conn) return -1; 4164 return sm_conn->sm_le_db_index; 4165 } 4166 4167 static int gap_random_address_type_requires_updates(void){ 4168 switch (gap_random_adress_type){ 4169 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4170 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4171 return 0; 4172 default: 4173 return 1; 4174 } 4175 } 4176 4177 static uint8_t own_address_type(void){ 4178 switch (gap_random_adress_type){ 4179 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4180 return BD_ADDR_TYPE_LE_PUBLIC; 4181 default: 4182 return BD_ADDR_TYPE_LE_RANDOM; 4183 } 4184 } 4185 4186 // GAP LE API 4187 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4188 gap_random_address_update_stop(); 4189 gap_random_adress_type = random_address_type; 4190 hci_le_set_own_address_type(own_address_type()); 4191 if (!gap_random_address_type_requires_updates()) return; 4192 gap_random_address_update_start(); 4193 gap_random_address_trigger(); 4194 } 4195 4196 gap_random_address_type_t gap_random_address_get_mode(void){ 4197 return gap_random_adress_type; 4198 } 4199 4200 void gap_random_address_set_update_period(int period_ms){ 4201 gap_random_adress_update_period = period_ms; 4202 if (!gap_random_address_type_requires_updates()) return; 4203 gap_random_address_update_stop(); 4204 gap_random_address_update_start(); 4205 } 4206 4207 void gap_random_address_set(bd_addr_t addr){ 4208 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4209 memcpy(sm_random_address, addr, 6); 4210 rau_state = RAU_SET_ADDRESS; 4211 sm_run(); 4212 } 4213 4214 #ifdef ENABLE_LE_PERIPHERAL 4215 /* 4216 * @brief Set Advertisement Paramters 4217 * @param adv_int_min 4218 * @param adv_int_max 4219 * @param adv_type 4220 * @param direct_address_type 4221 * @param direct_address 4222 * @param channel_map 4223 * @param filter_policy 4224 * 4225 * @note own_address_type is used from gap_random_address_set_mode 4226 */ 4227 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4228 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4229 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4230 direct_address_typ, direct_address, channel_map, filter_policy); 4231 } 4232 #endif 4233 4234 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4235 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4236 // wrong connection 4237 if (!sm_conn) return 0; 4238 // already encrypted 4239 if (sm_conn->sm_connection_encrypted) return 0; 4240 // only central can re-encrypt 4241 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4242 // irk status? 4243 switch(sm_conn->sm_irk_lookup_state){ 4244 case IRK_LOOKUP_FAILED: 4245 // done, cannot setup encryption 4246 return 0; 4247 case IRK_LOOKUP_SUCCEEDED: 4248 break; 4249 default: 4250 // IR Lookup pending 4251 return 1; 4252 } 4253 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4254 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4255 } 4256