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 bool test_use_fixed_local_csrk; 178 static bool test_use_fixed_local_irk; 179 180 #ifdef ENABLE_TESTING_SUPPORT 181 static uint8_t test_pairing_failure; 182 #endif 183 184 // configuration 185 static uint8_t sm_accepted_stk_generation_methods; 186 static uint8_t sm_max_encryption_key_size; 187 static uint8_t sm_min_encryption_key_size; 188 static uint8_t sm_auth_req = 0; 189 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 190 static uint8_t sm_slave_request_security; 191 static uint32_t sm_fixed_passkey_in_display_role; 192 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 193 194 #ifdef ENABLE_LE_SECURE_CONNECTIONS 195 static uint8_t sm_sc_oob_random[16]; 196 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 197 static sm_sc_oob_state_t sm_sc_oob_state; 198 #endif 199 200 201 static uint8_t sm_persistent_keys_random_active; 202 static const btstack_tlv_t * sm_tlv_impl; 203 static void * sm_tlv_context; 204 205 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 206 static sm_key_t sm_persistent_er; 207 static sm_key_t sm_persistent_ir; 208 209 // derived from sm_persistent_ir 210 static sm_key_t sm_persistent_dhk; 211 static sm_key_t sm_persistent_irk; 212 static derived_key_generation_t dkg_state; 213 214 // derived from sm_persistent_er 215 // .. 216 217 // random address update 218 static random_address_update_t rau_state; 219 static bd_addr_t sm_random_address; 220 221 #ifdef USE_CMAC_ENGINE 222 // CMAC Calculation: General 223 static btstack_crypto_aes128_cmac_t sm_cmac_request; 224 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 225 static uint8_t sm_cmac_active; 226 static uint8_t sm_cmac_hash[16]; 227 #endif 228 229 // CMAC for ATT Signed Writes 230 #ifdef ENABLE_LE_SIGNED_WRITE 231 static uint16_t sm_cmac_signed_write_message_len; 232 static uint8_t sm_cmac_signed_write_header[3]; 233 static const uint8_t * sm_cmac_signed_write_message; 234 static uint8_t sm_cmac_signed_write_sign_counter[4]; 235 #endif 236 237 // CMAC for Secure Connection functions 238 #ifdef ENABLE_LE_SECURE_CONNECTIONS 239 static sm_connection_t * sm_cmac_connection; 240 static uint8_t sm_cmac_sc_buffer[80]; 241 #endif 242 243 // resolvable private address lookup / CSRK calculation 244 static int sm_address_resolution_test; 245 static int sm_address_resolution_ah_calculation_active; 246 static uint8_t sm_address_resolution_addr_type; 247 static bd_addr_t sm_address_resolution_address; 248 static void * sm_address_resolution_context; 249 static address_resolution_mode_t sm_address_resolution_mode; 250 static btstack_linked_list_t sm_address_resolution_general_queue; 251 252 // aes128 crypto engine. 253 static sm_aes128_state_t sm_aes128_state; 254 255 // crypto 256 static btstack_crypto_random_t sm_crypto_random_request; 257 static btstack_crypto_aes128_t sm_crypto_aes128_request; 258 #ifdef ENABLE_LE_SECURE_CONNECTIONS 259 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 260 static btstack_crypto_random_t sm_crypto_random_oob_request; 261 #endif 262 263 // temp storage for random data 264 static uint8_t sm_random_data[8]; 265 static uint8_t sm_aes128_key[16]; 266 static uint8_t sm_aes128_plaintext[16]; 267 static uint8_t sm_aes128_ciphertext[16]; 268 269 // to receive hci events 270 static btstack_packet_callback_registration_t hci_event_callback_registration; 271 272 /* to dispatch sm event */ 273 static btstack_linked_list_t sm_event_handlers; 274 275 // LE Secure Connections 276 #ifdef ENABLE_LE_SECURE_CONNECTIONS 277 static ec_key_generation_state_t ec_key_generation_state; 278 static uint8_t ec_q[64]; 279 #endif 280 281 // 282 // Volume 3, Part H, Chapter 24 283 // "Security shall be initiated by the Security Manager in the device in the master role. 284 // The device in the slave role shall be the responding device." 285 // -> master := initiator, slave := responder 286 // 287 288 // data needed for security setup 289 typedef struct sm_setup_context { 290 291 btstack_timer_source_t sm_timeout; 292 293 // used in all phases 294 uint8_t sm_pairing_failed_reason; 295 296 // user response, (Phase 1 and/or 2) 297 uint8_t sm_user_response; 298 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 299 300 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 301 uint8_t sm_key_distribution_send_set; 302 uint8_t sm_key_distribution_sent_set; 303 uint8_t sm_key_distribution_received_set; 304 305 // Phase 2 (Pairing over SMP) 306 stk_generation_method_t sm_stk_generation_method; 307 sm_key_t sm_tk; 308 uint8_t sm_have_oob_data; 309 uint8_t sm_use_secure_connections; 310 311 sm_key_t sm_c1_t3_value; // c1 calculation 312 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 313 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 314 sm_key_t sm_local_random; 315 sm_key_t sm_local_confirm; 316 sm_key_t sm_peer_random; 317 sm_key_t sm_peer_confirm; 318 uint8_t sm_m_addr_type; // address and type can be removed 319 uint8_t sm_s_addr_type; // '' 320 bd_addr_t sm_m_address; // '' 321 bd_addr_t sm_s_address; // '' 322 sm_key_t sm_ltk; 323 324 uint8_t sm_state_vars; 325 #ifdef ENABLE_LE_SECURE_CONNECTIONS 326 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 327 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 328 sm_key_t sm_local_nonce; // might be combined with sm_local_random 329 sm_key_t sm_dhkey; 330 sm_key_t sm_peer_dhkey_check; 331 sm_key_t sm_local_dhkey_check; 332 sm_key_t sm_ra; 333 sm_key_t sm_rb; 334 sm_key_t sm_t; // used for f5 and h6 335 sm_key_t sm_mackey; 336 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 337 #endif 338 339 // Phase 3 340 341 // key distribution, we generate 342 uint16_t sm_local_y; 343 uint16_t sm_local_div; 344 uint16_t sm_local_ediv; 345 uint8_t sm_local_rand[8]; 346 sm_key_t sm_local_ltk; 347 sm_key_t sm_local_csrk; 348 sm_key_t sm_local_irk; 349 // sm_local_address/addr_type not needed 350 351 // key distribution, received from peer 352 uint16_t sm_peer_y; 353 uint16_t sm_peer_div; 354 uint16_t sm_peer_ediv; 355 uint8_t sm_peer_rand[8]; 356 sm_key_t sm_peer_ltk; 357 sm_key_t sm_peer_irk; 358 sm_key_t sm_peer_csrk; 359 uint8_t sm_peer_addr_type; 360 bd_addr_t sm_peer_address; 361 #ifdef ENABLE_LE_SIGNED_WRITE 362 int sm_le_device_index; 363 #endif 364 365 } sm_setup_context_t; 366 367 // 368 static sm_setup_context_t the_setup; 369 static sm_setup_context_t * setup = &the_setup; 370 371 // active connection - the one for which the_setup is used for 372 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 373 374 // @returns 1 if oob data is available 375 // stores oob data in provided 16 byte buffer if not null 376 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 377 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); 378 379 // horizontal: initiator capabilities 380 // vertial: responder capabilities 381 static const stk_generation_method_t stk_generation_method [5] [5] = { 382 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 383 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 384 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 385 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 386 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 387 }; 388 389 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 390 #ifdef ENABLE_LE_SECURE_CONNECTIONS 391 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 392 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 393 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 394 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 395 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 396 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 397 }; 398 #endif 399 400 static void sm_run(void); 401 static void sm_done_for_handle(hci_con_handle_t con_handle); 402 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 403 static inline int sm_calc_actual_encryption_key_size(int other); 404 static int sm_validate_stk_generation_method(void); 405 static void sm_handle_encryption_result_address_resolution(void *arg); 406 static void sm_handle_encryption_result_dkg_dhk(void *arg); 407 static void sm_handle_encryption_result_dkg_irk(void *arg); 408 static void sm_handle_encryption_result_enc_a(void *arg); 409 static void sm_handle_encryption_result_enc_b(void *arg); 410 static void sm_handle_encryption_result_enc_c(void *arg); 411 static void sm_handle_encryption_result_enc_csrk(void *arg); 412 static void sm_handle_encryption_result_enc_d(void * arg); 413 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 414 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 415 #ifdef ENABLE_LE_PERIPHERAL 416 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 417 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 418 #endif 419 static void sm_handle_encryption_result_enc_stk(void *arg); 420 static void sm_handle_encryption_result_rau(void *arg); 421 static void sm_handle_random_result_ph2_tk(void * arg); 422 static void sm_handle_random_result_rau(void * arg); 423 #ifdef ENABLE_LE_SECURE_CONNECTIONS 424 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)); 425 static void sm_ec_generate_new_key(void); 426 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 427 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 428 static int sm_passkey_entry(stk_generation_method_t method); 429 #endif 430 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 431 432 static void log_info_hex16(const char * name, uint16_t value){ 433 log_info("%-6s 0x%04x", name, value); 434 } 435 436 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 437 // return packet[0]; 438 // } 439 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 440 return packet[1]; 441 } 442 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 443 return packet[2]; 444 } 445 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 446 return packet[3]; 447 } 448 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 449 return packet[4]; 450 } 451 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 452 return packet[5]; 453 } 454 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 455 return packet[6]; 456 } 457 458 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 459 packet[0] = code; 460 } 461 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 462 packet[1] = io_capability; 463 } 464 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 465 packet[2] = oob_data_flag; 466 } 467 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 468 packet[3] = auth_req; 469 } 470 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 471 packet[4] = max_encryption_key_size; 472 } 473 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 474 packet[5] = initiator_key_distribution; 475 } 476 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 477 packet[6] = responder_key_distribution; 478 } 479 480 // @returns 1 if all bytes are 0 481 static int sm_is_null(uint8_t * data, int size){ 482 int i; 483 for (i=0; i < size ; i++){ 484 if (data[i]) return 0; 485 } 486 return 1; 487 } 488 489 static int sm_is_null_random(uint8_t random[8]){ 490 return sm_is_null(random, 8); 491 } 492 493 static int sm_is_null_key(uint8_t * key){ 494 return sm_is_null(key, 16); 495 } 496 497 // Key utils 498 static void sm_reset_tk(void){ 499 int i; 500 for (i=0;i<16;i++){ 501 setup->sm_tk[i] = 0; 502 } 503 } 504 505 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 506 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 507 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 508 int i; 509 for (i = max_encryption_size ; i < 16 ; i++){ 510 key[15-i] = 0; 511 } 512 } 513 514 // ER / IR checks 515 static void sm_er_ir_set_default(void){ 516 int i; 517 for (i=0;i<16;i++){ 518 sm_persistent_er[i] = 0x30 + i; 519 sm_persistent_ir[i] = 0x90 + i; 520 } 521 } 522 523 static int sm_er_is_default(void){ 524 int i; 525 for (i=0;i<16;i++){ 526 if (sm_persistent_er[i] != (0x30+i)) return 0; 527 } 528 return 1; 529 } 530 531 static int sm_ir_is_default(void){ 532 int i; 533 for (i=0;i<16;i++){ 534 if (sm_persistent_ir[i] != (0x90+i)) return 0; 535 } 536 return 1; 537 } 538 539 // SMP Timeout implementation 540 541 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 542 // the Security Manager Timer shall be reset and started. 543 // 544 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 545 // 546 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 547 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 548 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 549 // established. 550 551 static void sm_timeout_handler(btstack_timer_source_t * timer){ 552 log_info("SM timeout"); 553 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 554 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 555 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 556 sm_done_for_handle(sm_conn->sm_handle); 557 558 // trigger handling of next ready connection 559 sm_run(); 560 } 561 static void sm_timeout_start(sm_connection_t * sm_conn){ 562 btstack_run_loop_remove_timer(&setup->sm_timeout); 563 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 564 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 565 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 566 btstack_run_loop_add_timer(&setup->sm_timeout); 567 } 568 static void sm_timeout_stop(void){ 569 btstack_run_loop_remove_timer(&setup->sm_timeout); 570 } 571 static void sm_timeout_reset(sm_connection_t * sm_conn){ 572 sm_timeout_stop(); 573 sm_timeout_start(sm_conn); 574 } 575 576 // end of sm timeout 577 578 // GAP Random Address updates 579 static gap_random_address_type_t gap_random_adress_type; 580 static btstack_timer_source_t gap_random_address_update_timer; 581 static uint32_t gap_random_adress_update_period; 582 583 static void gap_random_address_trigger(void){ 584 log_info("gap_random_address_trigger, state %u", rau_state); 585 if (rau_state != RAU_IDLE) return; 586 rau_state = RAU_GET_RANDOM; 587 sm_run(); 588 } 589 590 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 591 UNUSED(timer); 592 593 log_info("GAP Random Address Update due"); 594 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 595 btstack_run_loop_add_timer(&gap_random_address_update_timer); 596 gap_random_address_trigger(); 597 } 598 599 static void gap_random_address_update_start(void){ 600 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 601 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 602 btstack_run_loop_add_timer(&gap_random_address_update_timer); 603 } 604 605 static void gap_random_address_update_stop(void){ 606 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 607 } 608 609 // ah(k,r) helper 610 // r = padding || r 611 // r - 24 bit value 612 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 613 // r'= padding || r 614 memset(r_prime, 0, 16); 615 (void)memcpy(&r_prime[13], r, 3); 616 } 617 618 // d1 helper 619 // d' = padding || r || d 620 // d,r - 16 bit values 621 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 622 // d'= padding || r || d 623 memset(d1_prime, 0, 16); 624 big_endian_store_16(d1_prime, 12, r); 625 big_endian_store_16(d1_prime, 14, d); 626 } 627 628 // calculate arguments for first AES128 operation in C1 function 629 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){ 630 631 // p1 = pres || preq || rat’ || iat’ 632 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 633 // cant octet of pres becomes the most significant octet of p1. 634 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 635 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 636 // p1 is 0x05000800000302070710000001010001." 637 638 sm_key_t p1; 639 reverse_56(pres, &p1[0]); 640 reverse_56(preq, &p1[7]); 641 p1[14] = rat; 642 p1[15] = iat; 643 log_info_key("p1", p1); 644 log_info_key("r", r); 645 646 // t1 = r xor p1 647 int i; 648 for (i=0;i<16;i++){ 649 t1[i] = r[i] ^ p1[i]; 650 } 651 log_info_key("t1", t1); 652 } 653 654 // calculate arguments for second AES128 operation in C1 function 655 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 656 // p2 = padding || ia || ra 657 // "The least significant octet of ra becomes the least significant octet of p2 and 658 // the most significant octet of padding becomes the most significant octet of p2. 659 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 660 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 661 662 sm_key_t p2; 663 memset(p2, 0, 16); 664 (void)memcpy(&p2[4], ia, 6); 665 (void)memcpy(&p2[10], ra, 6); 666 log_info_key("p2", p2); 667 668 // c1 = e(k, t2_xor_p2) 669 int i; 670 for (i=0;i<16;i++){ 671 t3[i] = t2[i] ^ p2[i]; 672 } 673 log_info_key("t3", t3); 674 } 675 676 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 677 log_info_key("r1", r1); 678 log_info_key("r2", r2); 679 (void)memcpy(&r_prime[8], &r2[8], 8); 680 (void)memcpy(&r_prime[0], &r1[8], 8); 681 } 682 683 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 684 UNUSED(channel); 685 686 // log event 687 hci_dump_packet(packet_type, 1, packet, size); 688 // dispatch to all event handlers 689 btstack_linked_list_iterator_t it; 690 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 691 while (btstack_linked_list_iterator_has_next(&it)){ 692 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 693 entry->callback(packet_type, 0, packet, size); 694 } 695 } 696 697 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){ 698 event[0] = type; 699 event[1] = event_size - 2; 700 little_endian_store_16(event, 2, con_handle); 701 event[4] = addr_type; 702 reverse_bd_addr(address, &event[5]); 703 } 704 705 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 706 uint8_t event[11]; 707 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 708 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 709 } 710 711 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){ 712 uint8_t event[15]; 713 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 714 little_endian_store_32(event, 11, passkey); 715 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 716 } 717 718 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){ 719 // fetch addr and addr type from db, only called for valid entries 720 bd_addr_t identity_address; 721 int identity_address_type; 722 le_device_db_info(index, &identity_address_type, identity_address, NULL); 723 724 uint8_t event[20]; 725 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 726 event[11] = identity_address_type; 727 reverse_bd_addr(identity_address, &event[12]); 728 little_endian_store_16(event, 18, index); 729 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 730 } 731 732 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){ 733 uint8_t event[12]; 734 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 735 event[11] = status; 736 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 737 } 738 739 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 740 uint8_t event[13]; 741 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 742 event[11] = status; 743 event[12] = reason; 744 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 745 } 746 747 // decide on stk generation based on 748 // - pairing request 749 // - io capabilities 750 // - OOB data availability 751 static void sm_setup_tk(void){ 752 753 // default: just works 754 setup->sm_stk_generation_method = JUST_WORKS; 755 756 #ifdef ENABLE_LE_SECURE_CONNECTIONS 757 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 758 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 759 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 760 #else 761 setup->sm_use_secure_connections = 0; 762 #endif 763 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 764 765 766 // decide if OOB will be used based on SC vs. Legacy and oob flags 767 int use_oob = 0; 768 if (setup->sm_use_secure_connections){ 769 // In LE Secure Connections pairing, the out of band method is used if at least 770 // one device has the peer device's out of band authentication data available. 771 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 772 } else { 773 // In LE legacy pairing, the out of band method is used if both the devices have 774 // the other device's out of band authentication data available. 775 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 776 } 777 if (use_oob){ 778 log_info("SM: have OOB data"); 779 log_info_key("OOB", setup->sm_tk); 780 setup->sm_stk_generation_method = OOB; 781 return; 782 } 783 784 // If both devices have not set the MITM option in the Authentication Requirements 785 // Flags, then the IO capabilities shall be ignored and the Just Works association 786 // model shall be used. 787 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 788 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 789 log_info("SM: MITM not required by both -> JUST WORKS"); 790 return; 791 } 792 793 // Reset TK as it has been setup in sm_init_setup 794 sm_reset_tk(); 795 796 // Also use just works if unknown io capabilites 797 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)){ 798 return; 799 } 800 801 // Otherwise the IO capabilities of the devices shall be used to determine the 802 // pairing method as defined in Table 2.4. 803 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 804 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 805 806 #ifdef ENABLE_LE_SECURE_CONNECTIONS 807 // table not define by default 808 if (setup->sm_use_secure_connections){ 809 generation_method = stk_generation_method_with_secure_connection; 810 } 811 #endif 812 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)]; 813 814 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 815 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); 816 } 817 818 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 819 int flags = 0; 820 if (key_set & SM_KEYDIST_ENC_KEY){ 821 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 822 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 823 } 824 if (key_set & SM_KEYDIST_ID_KEY){ 825 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 826 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 827 } 828 if (key_set & SM_KEYDIST_SIGN){ 829 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 830 } 831 return flags; 832 } 833 834 static void sm_setup_key_distribution(uint8_t key_set){ 835 setup->sm_key_distribution_received_set = 0; 836 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 837 setup->sm_key_distribution_sent_set = 0; 838 #ifdef ENABLE_LE_SIGNED_WRITE 839 setup->sm_le_device_index = -1; 840 #endif 841 } 842 843 // CSRK Key Lookup 844 845 846 static int sm_address_resolution_idle(void){ 847 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 848 } 849 850 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 851 (void)memcpy(sm_address_resolution_address, addr, 6); 852 sm_address_resolution_addr_type = addr_type; 853 sm_address_resolution_test = 0; 854 sm_address_resolution_mode = mode; 855 sm_address_resolution_context = context; 856 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 857 } 858 859 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 860 // check if already in list 861 btstack_linked_list_iterator_t it; 862 sm_lookup_entry_t * entry; 863 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 864 while(btstack_linked_list_iterator_has_next(&it)){ 865 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 866 if (entry->address_type != address_type) continue; 867 if (memcmp(entry->address, address, 6)) continue; 868 // already in list 869 return BTSTACK_BUSY; 870 } 871 entry = btstack_memory_sm_lookup_entry_get(); 872 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 873 entry->address_type = (bd_addr_type_t) address_type; 874 (void)memcpy(entry->address, address, 6); 875 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 876 sm_run(); 877 return 0; 878 } 879 880 // CMAC calculation using AES Engineq 881 #ifdef USE_CMAC_ENGINE 882 883 static void sm_cmac_done_trampoline(void * arg){ 884 UNUSED(arg); 885 sm_cmac_active = 0; 886 (*sm_cmac_done_callback)(sm_cmac_hash); 887 sm_run(); 888 } 889 890 int sm_cmac_ready(void){ 891 return sm_cmac_active == 0; 892 } 893 #endif 894 895 #ifdef ENABLE_LE_SECURE_CONNECTIONS 896 // generic cmac calculation 897 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)){ 898 sm_cmac_active = 1; 899 sm_cmac_done_callback = done_callback; 900 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 901 } 902 #endif 903 904 // cmac for ATT Message signing 905 #ifdef ENABLE_LE_SIGNED_WRITE 906 907 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)){ 908 sm_cmac_active = 1; 909 sm_cmac_done_callback = done_callback; 910 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 911 } 912 913 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 914 if (offset >= sm_cmac_signed_write_message_len) { 915 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 916 return 0; 917 } 918 919 offset = sm_cmac_signed_write_message_len - 1 - offset; 920 921 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 922 if (offset < 3){ 923 return sm_cmac_signed_write_header[offset]; 924 } 925 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 926 if (offset < actual_message_len_incl_header){ 927 return sm_cmac_signed_write_message[offset - 3]; 928 } 929 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 930 } 931 932 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)){ 933 // ATT Message Signing 934 sm_cmac_signed_write_header[0] = opcode; 935 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 936 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 937 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 938 sm_cmac_signed_write_message = message; 939 sm_cmac_signed_write_message_len = total_message_len; 940 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 941 } 942 #endif 943 944 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 945 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 946 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 947 switch (setup->sm_stk_generation_method){ 948 case PK_RESP_INPUT: 949 if (IS_RESPONDER(sm_conn->sm_role)){ 950 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 951 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 952 } else { 953 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)); 954 } 955 break; 956 case PK_INIT_INPUT: 957 if (IS_RESPONDER(sm_conn->sm_role)){ 958 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)); 959 } else { 960 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 961 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 962 } 963 break; 964 case PK_BOTH_INPUT: 965 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 966 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 967 break; 968 case NUMERIC_COMPARISON: 969 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 970 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)); 971 break; 972 case JUST_WORKS: 973 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 974 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 975 break; 976 case OOB: 977 // client already provided OOB data, let's skip notification. 978 break; 979 } 980 } 981 982 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 983 int recv_flags; 984 if (IS_RESPONDER(sm_conn->sm_role)){ 985 // slave / responder 986 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 987 } else { 988 // master / initiator 989 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 990 } 991 992 #ifdef ENABLE_LE_SECURE_CONNECTIONS 993 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 994 if (setup->sm_use_secure_connections){ 995 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 996 } 997 #endif 998 999 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1000 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1001 } 1002 1003 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1004 if (sm_active_connection_handle == con_handle){ 1005 sm_timeout_stop(); 1006 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1007 log_info("sm: connection 0x%x released setup context", con_handle); 1008 1009 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1010 // generate new ec key after each pairing (that used it) 1011 if (setup->sm_use_secure_connections){ 1012 sm_ec_generate_new_key(); 1013 } 1014 #endif 1015 } 1016 } 1017 1018 void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1019 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1020 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1021 sm_done_for_handle(connection->sm_handle); 1022 } 1023 1024 static int sm_key_distribution_flags_for_auth_req(void){ 1025 1026 int flags = SM_KEYDIST_ID_KEY; 1027 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1028 // encryption and signing information only if bonding requested 1029 flags |= SM_KEYDIST_ENC_KEY; 1030 #ifdef ENABLE_LE_SIGNED_WRITE 1031 flags |= SM_KEYDIST_SIGN; 1032 #endif 1033 } 1034 return flags; 1035 } 1036 1037 static void sm_reset_setup(void){ 1038 // fill in sm setup 1039 setup->sm_state_vars = 0; 1040 setup->sm_keypress_notification = 0; 1041 sm_reset_tk(); 1042 } 1043 1044 static void sm_init_setup(sm_connection_t * sm_conn){ 1045 1046 // fill in sm setup 1047 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1048 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1049 1050 // query client for Legacy Pairing OOB data 1051 setup->sm_have_oob_data = 0; 1052 if (sm_get_oob_data) { 1053 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1054 } 1055 1056 // if available and SC supported, also ask for SC OOB Data 1057 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1058 memset(setup->sm_ra, 0, 16); 1059 memset(setup->sm_rb, 0, 16); 1060 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1061 if (sm_get_sc_oob_data){ 1062 if (IS_RESPONDER(sm_conn->sm_role)){ 1063 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1064 sm_conn->sm_peer_addr_type, 1065 sm_conn->sm_peer_address, 1066 setup->sm_peer_confirm, 1067 setup->sm_ra); 1068 } else { 1069 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1070 sm_conn->sm_peer_addr_type, 1071 sm_conn->sm_peer_address, 1072 setup->sm_peer_confirm, 1073 setup->sm_rb); 1074 } 1075 } else { 1076 setup->sm_have_oob_data = 0; 1077 } 1078 } 1079 #endif 1080 1081 sm_pairing_packet_t * local_packet; 1082 if (IS_RESPONDER(sm_conn->sm_role)){ 1083 // slave 1084 local_packet = &setup->sm_s_pres; 1085 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1086 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1087 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1088 } else { 1089 // master 1090 local_packet = &setup->sm_m_preq; 1091 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1092 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1093 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1094 1095 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1096 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1097 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1098 } 1099 1100 uint8_t auth_req = sm_auth_req; 1101 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1102 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1103 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1104 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1105 } 1106 1107 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1108 1109 sm_pairing_packet_t * remote_packet; 1110 int remote_key_request; 1111 if (IS_RESPONDER(sm_conn->sm_role)){ 1112 // slave / responder 1113 remote_packet = &setup->sm_m_preq; 1114 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1115 } else { 1116 // master / initiator 1117 remote_packet = &setup->sm_s_pres; 1118 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1119 } 1120 1121 // check key size 1122 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1123 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1124 1125 // decide on STK generation method / SC 1126 sm_setup_tk(); 1127 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1128 1129 // check if STK generation method is acceptable by client 1130 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1131 1132 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1133 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1134 if (setup->sm_use_secure_connections){ 1135 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1136 } 1137 #endif 1138 1139 // identical to responder 1140 sm_setup_key_distribution(remote_key_request); 1141 1142 // JUST WORKS doens't provide authentication 1143 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1144 1145 return 0; 1146 } 1147 1148 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1149 1150 // cache and reset context 1151 int matched_device_id = sm_address_resolution_test; 1152 address_resolution_mode_t mode = sm_address_resolution_mode; 1153 void * context = sm_address_resolution_context; 1154 1155 // reset context 1156 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1157 sm_address_resolution_context = NULL; 1158 sm_address_resolution_test = -1; 1159 hci_con_handle_t con_handle = 0; 1160 1161 sm_connection_t * sm_connection; 1162 #ifdef ENABLE_LE_CENTRAL 1163 sm_key_t ltk; 1164 int have_ltk; 1165 int pairing_need; 1166 #endif 1167 switch (mode){ 1168 case ADDRESS_RESOLUTION_GENERAL: 1169 break; 1170 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1171 sm_connection = (sm_connection_t *) context; 1172 con_handle = sm_connection->sm_handle; 1173 switch (event){ 1174 case ADDRESS_RESOLUTION_SUCEEDED: 1175 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1176 sm_connection->sm_le_db_index = matched_device_id; 1177 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1178 if (sm_connection->sm_role) { 1179 // LTK request received before, IRK required -> start LTK calculation 1180 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1181 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1182 } 1183 break; 1184 } 1185 #ifdef ENABLE_LE_CENTRAL 1186 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1187 have_ltk = !sm_is_null_key(ltk); 1188 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1189 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1190 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1191 // reset requests 1192 sm_connection->sm_security_request_received = 0; 1193 sm_connection->sm_pairing_requested = 0; 1194 1195 // have ltk -> start encryption 1196 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1197 // "When a bond has been created between two devices, any reconnection should result in the local device 1198 // enabling or requesting encryption with the remote device before initiating any service request." 1199 if (have_ltk){ 1200 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1202 break; 1203 #else 1204 log_info("central: defer enabling encryption for bonded device"); 1205 #endif 1206 } 1207 // pairint_request -> send pairing request 1208 if (pairing_need){ 1209 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1210 break; 1211 } 1212 #endif 1213 break; 1214 case ADDRESS_RESOLUTION_FAILED: 1215 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1216 if (sm_connection->sm_role) { 1217 // LTK request received before, IRK required -> negative LTK reply 1218 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1219 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1220 } 1221 break; 1222 } 1223 #ifdef ENABLE_LE_CENTRAL 1224 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1225 sm_connection->sm_security_request_received = 0; 1226 sm_connection->sm_pairing_requested = 0; 1227 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1228 #endif 1229 break; 1230 } 1231 break; 1232 default: 1233 break; 1234 } 1235 1236 switch (event){ 1237 case ADDRESS_RESOLUTION_SUCEEDED: 1238 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1239 break; 1240 case ADDRESS_RESOLUTION_FAILED: 1241 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1242 break; 1243 } 1244 } 1245 1246 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1247 1248 int le_db_index = -1; 1249 1250 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1251 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1252 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1253 & SM_AUTHREQ_BONDING ) != 0; 1254 1255 if (bonding_enabed){ 1256 1257 // lookup device based on IRK 1258 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1259 int i; 1260 for (i=0; i < le_device_db_max_count(); i++){ 1261 sm_key_t irk; 1262 bd_addr_t address; 1263 int address_type = BD_ADDR_TYPE_UNKNOWN; 1264 le_device_db_info(i, &address_type, address, irk); 1265 // skip unused entries 1266 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1267 // compare IRK 1268 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1269 1270 log_info("sm: device found for IRK, updating"); 1271 le_db_index = i; 1272 break; 1273 } 1274 } else { 1275 // assert IRK is set to zero 1276 memset(setup->sm_peer_irk, 0, 16); 1277 } 1278 1279 // if not found, lookup via public address if possible 1280 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1281 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1282 int i; 1283 for (i=0; i < le_device_db_max_count(); i++){ 1284 bd_addr_t address; 1285 int address_type = BD_ADDR_TYPE_UNKNOWN; 1286 le_device_db_info(i, &address_type, address, NULL); 1287 // skip unused entries 1288 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1289 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1290 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1291 log_info("sm: device found for public address, updating"); 1292 le_db_index = i; 1293 break; 1294 } 1295 } 1296 } 1297 1298 // if not found, add to db 1299 if (le_db_index < 0) { 1300 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1301 } 1302 1303 if (le_db_index >= 0){ 1304 1305 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1306 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1307 1308 #ifdef ENABLE_LE_SIGNED_WRITE 1309 // store local CSRK 1310 setup->sm_le_device_index = le_db_index; 1311 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1312 log_info("sm: store local CSRK"); 1313 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1314 le_device_db_local_counter_set(le_db_index, 0); 1315 } 1316 1317 // store remote CSRK 1318 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1319 log_info("sm: store remote CSRK"); 1320 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1321 le_device_db_remote_counter_set(le_db_index, 0); 1322 } 1323 #endif 1324 // store encryption information for secure connections: LTK generated by ECDH 1325 if (setup->sm_use_secure_connections){ 1326 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1327 uint8_t zero_rand[8]; 1328 memset(zero_rand, 0, 8); 1329 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1330 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1331 } 1332 1333 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1334 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1335 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1336 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1337 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1338 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1339 1340 } 1341 } 1342 } else { 1343 log_info("Ignoring received keys, bonding not enabled"); 1344 } 1345 1346 // keep le_db_index 1347 sm_conn->sm_le_db_index = le_db_index; 1348 } 1349 1350 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1351 setup->sm_pairing_failed_reason = reason; 1352 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1353 } 1354 1355 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1356 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1357 } 1358 1359 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1360 1361 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1362 static int sm_passkey_used(stk_generation_method_t method); 1363 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1364 1365 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1366 if (setup->sm_stk_generation_method == OOB){ 1367 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1368 } else { 1369 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_w2_cmac_for_confirmation, (void *)(uintptr_t) sm_conn->sm_handle); 1370 } 1371 } 1372 1373 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1374 if (IS_RESPONDER(sm_conn->sm_role)){ 1375 // Responder 1376 if (setup->sm_stk_generation_method == OOB){ 1377 // generate Nb 1378 log_info("Generate Nb"); 1379 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void *)(uintptr_t) sm_conn->sm_handle); 1380 } else { 1381 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1382 } 1383 } else { 1384 // Initiator role 1385 switch (setup->sm_stk_generation_method){ 1386 case JUST_WORKS: 1387 sm_sc_prepare_dhkey_check(sm_conn); 1388 break; 1389 1390 case NUMERIC_COMPARISON: 1391 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1392 break; 1393 case PK_INIT_INPUT: 1394 case PK_RESP_INPUT: 1395 case PK_BOTH_INPUT: 1396 if (setup->sm_passkey_bit < 20) { 1397 sm_sc_start_calculating_local_confirm(sm_conn); 1398 } else { 1399 sm_sc_prepare_dhkey_check(sm_conn); 1400 } 1401 break; 1402 case OOB: 1403 sm_sc_prepare_dhkey_check(sm_conn); 1404 break; 1405 } 1406 } 1407 } 1408 1409 static void sm_sc_cmac_done(uint8_t * hash){ 1410 log_info("sm_sc_cmac_done: "); 1411 log_info_hexdump(hash, 16); 1412 1413 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1414 sm_sc_oob_state = SM_SC_OOB_IDLE; 1415 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1416 return; 1417 } 1418 1419 sm_connection_t * sm_conn = sm_cmac_connection; 1420 sm_cmac_connection = NULL; 1421 #ifdef ENABLE_CLASSIC 1422 link_key_type_t link_key_type; 1423 #endif 1424 1425 switch (sm_conn->sm_engine_state){ 1426 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1427 (void)memcpy(setup->sm_local_confirm, hash, 16); 1428 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1429 break; 1430 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1431 // check 1432 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1433 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1434 break; 1435 } 1436 sm_sc_state_after_receiving_random(sm_conn); 1437 break; 1438 case SM_SC_W4_CALCULATE_G2: { 1439 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1440 big_endian_store_32(setup->sm_tk, 12, vab); 1441 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1442 sm_trigger_user_response(sm_conn); 1443 break; 1444 } 1445 case SM_SC_W4_CALCULATE_F5_SALT: 1446 (void)memcpy(setup->sm_t, hash, 16); 1447 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1448 break; 1449 case SM_SC_W4_CALCULATE_F5_MACKEY: 1450 (void)memcpy(setup->sm_mackey, hash, 16); 1451 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1452 break; 1453 case SM_SC_W4_CALCULATE_F5_LTK: 1454 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1455 // Errata Service Release to the Bluetooth Specification: ESR09 1456 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1457 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1458 (void)memcpy(setup->sm_ltk, hash, 16); 1459 (void)memcpy(setup->sm_local_ltk, hash, 16); 1460 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1461 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1462 break; 1463 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1464 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1465 if (IS_RESPONDER(sm_conn->sm_role)){ 1466 // responder 1467 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1468 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1469 } else { 1470 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1471 } 1472 } else { 1473 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1474 } 1475 break; 1476 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1477 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1478 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1479 break; 1480 } 1481 if (IS_RESPONDER(sm_conn->sm_role)){ 1482 // responder 1483 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1484 } else { 1485 // initiator 1486 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1487 } 1488 break; 1489 case SM_SC_W4_CALCULATE_H6_ILK: 1490 (void)memcpy(setup->sm_t, hash, 16); 1491 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1492 break; 1493 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1494 #ifdef ENABLE_CLASSIC 1495 reverse_128(hash, setup->sm_t); 1496 link_key_type = sm_conn->sm_connection_authenticated ? 1497 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1498 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1499 if (IS_RESPONDER(sm_conn->sm_role)){ 1500 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1501 } else { 1502 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1503 } 1504 #endif 1505 if (IS_RESPONDER(sm_conn->sm_role)){ 1506 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1507 } else { 1508 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1509 } 1510 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1511 sm_done_for_handle(sm_conn->sm_handle); 1512 break; 1513 default: 1514 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1515 break; 1516 } 1517 sm_run(); 1518 } 1519 1520 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){ 1521 const uint16_t message_len = 65; 1522 sm_cmac_connection = sm_conn; 1523 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1524 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1525 sm_cmac_sc_buffer[64] = z; 1526 log_info("f4 key"); 1527 log_info_hexdump(x, 16); 1528 log_info("f4 message"); 1529 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1530 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1531 } 1532 1533 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1534 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1535 static const uint8_t f5_length[] = { 0x01, 0x00}; 1536 1537 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1538 log_info("f5_calculate_salt"); 1539 // calculate salt for f5 1540 const uint16_t message_len = 32; 1541 sm_cmac_connection = sm_conn; 1542 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1543 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1544 } 1545 1546 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){ 1547 const uint16_t message_len = 53; 1548 sm_cmac_connection = sm_conn; 1549 1550 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1551 sm_cmac_sc_buffer[0] = 0; 1552 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1553 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1554 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1555 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1556 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1557 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1558 log_info("f5 key"); 1559 log_info_hexdump(t, 16); 1560 log_info("f5 message for MacKey"); 1561 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1562 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1563 } 1564 1565 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1566 sm_key56_t bd_addr_master, bd_addr_slave; 1567 bd_addr_master[0] = setup->sm_m_addr_type; 1568 bd_addr_slave[0] = setup->sm_s_addr_type; 1569 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1570 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1571 if (IS_RESPONDER(sm_conn->sm_role)){ 1572 // responder 1573 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1574 } else { 1575 // initiator 1576 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1577 } 1578 } 1579 1580 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1581 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1582 const uint16_t message_len = 53; 1583 sm_cmac_connection = sm_conn; 1584 sm_cmac_sc_buffer[0] = 1; 1585 // 1..52 setup before 1586 log_info("f5 key"); 1587 log_info_hexdump(t, 16); 1588 log_info("f5 message for LTK"); 1589 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1590 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1591 } 1592 1593 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1594 f5_ltk(sm_conn, setup->sm_t); 1595 } 1596 1597 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){ 1598 const uint16_t message_len = 65; 1599 sm_cmac_connection = sm_conn; 1600 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1601 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1602 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1603 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1604 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1605 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1606 log_info("f6 key"); 1607 log_info_hexdump(w, 16); 1608 log_info("f6 message"); 1609 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1610 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1611 } 1612 1613 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1614 // - U is 256 bits 1615 // - V is 256 bits 1616 // - X is 128 bits 1617 // - Y is 128 bits 1618 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){ 1619 const uint16_t message_len = 80; 1620 sm_cmac_connection = sm_conn; 1621 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1622 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1623 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1624 log_info("g2 key"); 1625 log_info_hexdump(x, 16); 1626 log_info("g2 message"); 1627 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1628 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1629 } 1630 1631 static void g2_calculate(sm_connection_t * sm_conn) { 1632 // calc Va if numeric comparison 1633 if (IS_RESPONDER(sm_conn->sm_role)){ 1634 // responder 1635 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1636 } else { 1637 // initiator 1638 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1639 } 1640 } 1641 1642 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1643 uint8_t z = 0; 1644 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1645 // some form of passkey 1646 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1647 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1648 setup->sm_passkey_bit++; 1649 } 1650 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1651 } 1652 1653 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1654 // OOB 1655 if (setup->sm_stk_generation_method == OOB){ 1656 if (IS_RESPONDER(sm_conn->sm_role)){ 1657 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1658 } else { 1659 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1660 } 1661 return; 1662 } 1663 1664 uint8_t z = 0; 1665 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1666 // some form of passkey 1667 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1668 // sm_passkey_bit was increased before sending confirm value 1669 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1670 } 1671 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1672 } 1673 1674 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1675 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1676 1677 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1678 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1679 return; 1680 } else { 1681 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1682 } 1683 } 1684 1685 static void sm_sc_dhkey_calculated(void * arg){ 1686 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1687 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1688 if (sm_conn == NULL) return; 1689 1690 log_info("dhkey"); 1691 log_info_hexdump(&setup->sm_dhkey[0], 32); 1692 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1693 // trigger next step 1694 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1695 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1696 } 1697 sm_run(); 1698 } 1699 1700 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1701 // calculate DHKCheck 1702 sm_key56_t bd_addr_master, bd_addr_slave; 1703 bd_addr_master[0] = setup->sm_m_addr_type; 1704 bd_addr_slave[0] = setup->sm_s_addr_type; 1705 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1706 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1707 uint8_t iocap_a[3]; 1708 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1709 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1710 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1711 uint8_t iocap_b[3]; 1712 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1713 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1714 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1715 if (IS_RESPONDER(sm_conn->sm_role)){ 1716 // responder 1717 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); 1718 } else { 1719 // initiator 1720 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); 1721 } 1722 } 1723 1724 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1725 // validate E = f6() 1726 sm_key56_t bd_addr_master, bd_addr_slave; 1727 bd_addr_master[0] = setup->sm_m_addr_type; 1728 bd_addr_slave[0] = setup->sm_s_addr_type; 1729 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1730 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1731 1732 uint8_t iocap_a[3]; 1733 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1734 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1735 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1736 uint8_t iocap_b[3]; 1737 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1738 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1739 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1740 if (IS_RESPONDER(sm_conn->sm_role)){ 1741 // responder 1742 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); 1743 } else { 1744 // initiator 1745 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); 1746 } 1747 } 1748 1749 1750 // 1751 // Link Key Conversion Function h6 1752 // 1753 // h6(W, keyID) = AES-CMACW(keyID) 1754 // - W is 128 bits 1755 // - keyID is 32 bits 1756 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1757 const uint16_t message_len = 4; 1758 sm_cmac_connection = sm_conn; 1759 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1760 log_info("h6 key"); 1761 log_info_hexdump(w, 16); 1762 log_info("h6 message"); 1763 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1764 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1765 } 1766 1767 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1768 // Errata Service Release to the Bluetooth Specification: ESR09 1769 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1770 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1771 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1772 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1773 } 1774 1775 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1776 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1777 } 1778 1779 #endif 1780 1781 // key management legacy connections: 1782 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1783 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1784 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1785 // - responder reconnects: responder uses LTK receveived from master 1786 1787 // key management secure connections: 1788 // - both devices store same LTK from ECDH key exchange. 1789 1790 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1791 static void sm_load_security_info(sm_connection_t * sm_connection){ 1792 int encryption_key_size; 1793 int authenticated; 1794 int authorized; 1795 int secure_connection; 1796 1797 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1798 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1799 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1800 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); 1801 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1802 sm_connection->sm_connection_authenticated = authenticated; 1803 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1804 sm_connection->sm_connection_sc = secure_connection; 1805 } 1806 #endif 1807 1808 #ifdef ENABLE_LE_PERIPHERAL 1809 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1810 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1811 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1812 // re-establish used key encryption size 1813 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1814 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1815 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1816 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1817 // Legacy paring -> not SC 1818 sm_connection->sm_connection_sc = 0; 1819 log_info("sm: received ltk request with key size %u, authenticated %u", 1820 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1821 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1822 sm_run(); 1823 } 1824 #endif 1825 1826 static void sm_run(void){ 1827 1828 btstack_linked_list_iterator_t it; 1829 1830 // assert that stack has already bootet 1831 if (hci_get_state() != HCI_STATE_WORKING) return; 1832 1833 // assert that we can send at least commands 1834 if (!hci_can_send_command_packet_now()) return; 1835 1836 // pause until IR/ER are ready 1837 if (sm_persistent_keys_random_active) return; 1838 1839 // 1840 // non-connection related behaviour 1841 // 1842 1843 // distributed key generation 1844 switch (dkg_state){ 1845 case DKG_CALC_IRK: 1846 // already busy? 1847 if (sm_aes128_state == SM_AES128_IDLE) { 1848 log_info("DKG_CALC_IRK started"); 1849 // IRK = d1(IR, 1, 0) 1850 sm_d1_d_prime(1, 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_irk, sm_handle_encryption_result_dkg_irk, NULL); 1853 return; 1854 } 1855 break; 1856 case DKG_CALC_DHK: 1857 // already busy? 1858 if (sm_aes128_state == SM_AES128_IDLE) { 1859 log_info("DKG_CALC_DHK started"); 1860 // DHK = d1(IR, 3, 0) 1861 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1862 sm_aes128_state = SM_AES128_ACTIVE; 1863 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1864 return; 1865 } 1866 break; 1867 default: 1868 break; 1869 } 1870 1871 // random address updates 1872 switch (rau_state){ 1873 case RAU_GET_RANDOM: 1874 rau_state = RAU_W4_RANDOM; 1875 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1876 return; 1877 case RAU_GET_ENC: 1878 // already busy? 1879 if (sm_aes128_state == SM_AES128_IDLE) { 1880 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1881 sm_aes128_state = SM_AES128_ACTIVE; 1882 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1883 return; 1884 } 1885 break; 1886 case RAU_SET_ADDRESS: 1887 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1888 rau_state = RAU_IDLE; 1889 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1890 return; 1891 default: 1892 break; 1893 } 1894 1895 // CSRK Lookup 1896 // -- if csrk lookup ready, find connection that require csrk lookup 1897 if (sm_address_resolution_idle()){ 1898 hci_connections_get_iterator(&it); 1899 while(btstack_linked_list_iterator_has_next(&it)){ 1900 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1901 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1902 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1903 // and start lookup 1904 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); 1905 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1906 break; 1907 } 1908 } 1909 } 1910 1911 // -- if csrk lookup ready, resolved addresses for received addresses 1912 if (sm_address_resolution_idle()) { 1913 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1914 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1915 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1916 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1917 btstack_memory_sm_lookup_entry_free(entry); 1918 } 1919 } 1920 1921 // -- Continue with CSRK device lookup by public or resolvable private address 1922 if (!sm_address_resolution_idle()){ 1923 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1924 while (sm_address_resolution_test < le_device_db_max_count()){ 1925 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1926 bd_addr_t addr; 1927 sm_key_t irk; 1928 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1929 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1930 1931 // skip unused entries 1932 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1933 sm_address_resolution_test++; 1934 continue; 1935 } 1936 1937 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 1938 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1939 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1940 break; 1941 } 1942 1943 // if connection type is public, it must be a different one 1944 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1945 sm_address_resolution_test++; 1946 continue; 1947 } 1948 1949 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1950 1951 log_info("LE Device Lookup: calculate AH"); 1952 log_info_key("IRK", irk); 1953 1954 (void)memcpy(sm_aes128_key, irk, 16); 1955 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1956 sm_address_resolution_ah_calculation_active = 1; 1957 sm_aes128_state = SM_AES128_ACTIVE; 1958 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1959 return; 1960 } 1961 1962 if (sm_address_resolution_test >= le_device_db_max_count()){ 1963 log_info("LE Device Lookup: not found"); 1964 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1965 } 1966 } 1967 1968 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1969 switch (sm_sc_oob_state){ 1970 case SM_SC_OOB_W2_CALC_CONFIRM: 1971 if (!sm_cmac_ready()) break; 1972 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1973 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1974 return; 1975 default: 1976 break; 1977 } 1978 #endif 1979 1980 // assert that we can send at least commands - cmd might have been sent by crypto engine 1981 if (!hci_can_send_command_packet_now()) return; 1982 1983 // handle basic actions that don't requires the full context 1984 hci_connections_get_iterator(&it); 1985 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1986 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1987 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1988 switch(sm_connection->sm_engine_state){ 1989 // responder side 1990 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1991 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1992 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1993 return; 1994 1995 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1996 case SM_SC_RECEIVED_LTK_REQUEST: 1997 switch (sm_connection->sm_irk_lookup_state){ 1998 case IRK_LOOKUP_FAILED: 1999 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2000 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2001 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2002 return; 2003 default: 2004 break; 2005 } 2006 break; 2007 #endif 2008 default: 2009 break; 2010 } 2011 } 2012 2013 // 2014 // active connection handling 2015 // -- use loop to handle next connection if lock on setup context is released 2016 2017 while (true) { 2018 2019 // Find connections that requires setup context and make active if no other is locked 2020 hci_connections_get_iterator(&it); 2021 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2022 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2023 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2024 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2025 int done = 1; 2026 int err; 2027 UNUSED(err); 2028 2029 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2030 // assert ec key is ready 2031 if ((sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2032 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST)){ 2033 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2034 sm_ec_generate_new_key(); 2035 } 2036 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2037 continue; 2038 } 2039 } 2040 #endif 2041 2042 switch (sm_connection->sm_engine_state) { 2043 #ifdef ENABLE_LE_PERIPHERAL 2044 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2045 // send packet if possible, 2046 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2047 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2048 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2049 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2050 } else { 2051 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2052 } 2053 // don't lock sxetup context yet 2054 done = 0; 2055 break; 2056 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2057 sm_reset_setup(); 2058 sm_init_setup(sm_connection); 2059 // recover pairing request 2060 (void)memcpy(&setup->sm_m_preq, 2061 &sm_connection->sm_m_preq, 2062 sizeof(sm_pairing_packet_t)); 2063 err = sm_stk_generation_init(sm_connection); 2064 2065 #ifdef ENABLE_TESTING_SUPPORT 2066 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2067 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2068 err = test_pairing_failure; 2069 } 2070 #endif 2071 if (err){ 2072 setup->sm_pairing_failed_reason = err; 2073 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2074 break; 2075 } 2076 sm_timeout_start(sm_connection); 2077 // generate random number first, if we need to show passkey 2078 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2079 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_connection->sm_handle); 2080 break; 2081 } 2082 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2083 break; 2084 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2085 sm_reset_setup(); 2086 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2087 break; 2088 2089 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2090 case SM_SC_RECEIVED_LTK_REQUEST: 2091 switch (sm_connection->sm_irk_lookup_state){ 2092 case IRK_LOOKUP_SUCCEEDED: 2093 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2094 // start using context by loading security info 2095 sm_reset_setup(); 2096 sm_load_security_info(sm_connection); 2097 if ((setup->sm_peer_ediv == 0) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2098 (void)memcpy(setup->sm_ltk, 2099 setup->sm_peer_ltk, 16); 2100 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2101 break; 2102 } 2103 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2104 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2105 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2106 // don't lock setup context yet 2107 return; 2108 default: 2109 // just wait until IRK lookup is completed 2110 // don't lock setup context yet 2111 done = 0; 2112 break; 2113 } 2114 break; 2115 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2116 #endif /* ENABLE_LE_PERIPHERAL */ 2117 2118 #ifdef ENABLE_LE_CENTRAL 2119 case SM_INITIATOR_PH0_HAS_LTK: 2120 sm_reset_setup(); 2121 sm_load_security_info(sm_connection); 2122 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2123 break; 2124 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2125 sm_reset_setup(); 2126 sm_init_setup(sm_connection); 2127 sm_timeout_start(sm_connection); 2128 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2129 break; 2130 #endif 2131 2132 default: 2133 done = 0; 2134 break; 2135 } 2136 if (done){ 2137 sm_active_connection_handle = sm_connection->sm_handle; 2138 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); 2139 } 2140 } 2141 2142 // 2143 // active connection handling 2144 // 2145 2146 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2147 2148 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2149 if (!connection) { 2150 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2151 return; 2152 } 2153 2154 // assert that we could send a SM PDU - not needed for all of the following 2155 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2156 log_info("cannot send now, requesting can send now event"); 2157 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2158 return; 2159 } 2160 2161 // send keypress notifications 2162 if (setup->sm_keypress_notification){ 2163 int i; 2164 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2165 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2166 uint8_t action = 0; 2167 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2168 if (flags & (1<<i)){ 2169 int clear_flag = 1; 2170 switch (i){ 2171 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2172 case SM_KEYPRESS_PASSKEY_CLEARED: 2173 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2174 default: 2175 break; 2176 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2177 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2178 num_actions--; 2179 clear_flag = num_actions == 0; 2180 break; 2181 } 2182 if (clear_flag){ 2183 flags &= ~(1<<i); 2184 } 2185 action = i; 2186 break; 2187 } 2188 } 2189 setup->sm_keypress_notification = (num_actions << 5) | flags; 2190 2191 // send keypress notification 2192 uint8_t buffer[2]; 2193 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2194 buffer[1] = action; 2195 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2196 2197 // try 2198 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2199 return; 2200 } 2201 2202 int key_distribution_flags; 2203 UNUSED(key_distribution_flags); 2204 2205 log_info("sm_run: state %u", connection->sm_engine_state); 2206 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2207 log_info("sm_run // cannot send"); 2208 } 2209 switch (connection->sm_engine_state){ 2210 2211 // general 2212 case SM_GENERAL_SEND_PAIRING_FAILED: { 2213 uint8_t buffer[2]; 2214 buffer[0] = SM_CODE_PAIRING_FAILED; 2215 buffer[1] = setup->sm_pairing_failed_reason; 2216 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2217 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2218 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2219 sm_done_for_handle(connection->sm_handle); 2220 break; 2221 } 2222 2223 // responding state 2224 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2225 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2226 if (!sm_cmac_ready()) break; 2227 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2228 sm_sc_calculate_local_confirm(connection); 2229 break; 2230 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2231 if (!sm_cmac_ready()) break; 2232 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2233 sm_sc_calculate_remote_confirm(connection); 2234 break; 2235 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2236 if (!sm_cmac_ready()) break; 2237 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2238 sm_sc_calculate_f6_for_dhkey_check(connection); 2239 break; 2240 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2241 if (!sm_cmac_ready()) break; 2242 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2243 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2244 break; 2245 case SM_SC_W2_CALCULATE_F5_SALT: 2246 if (!sm_cmac_ready()) break; 2247 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2248 f5_calculate_salt(connection); 2249 break; 2250 case SM_SC_W2_CALCULATE_F5_MACKEY: 2251 if (!sm_cmac_ready()) break; 2252 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2253 f5_calculate_mackey(connection); 2254 break; 2255 case SM_SC_W2_CALCULATE_F5_LTK: 2256 if (!sm_cmac_ready()) break; 2257 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2258 f5_calculate_ltk(connection); 2259 break; 2260 case SM_SC_W2_CALCULATE_G2: 2261 if (!sm_cmac_ready()) break; 2262 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2263 g2_calculate(connection); 2264 break; 2265 case SM_SC_W2_CALCULATE_H6_ILK: 2266 if (!sm_cmac_ready()) break; 2267 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2268 h6_calculate_ilk(connection); 2269 break; 2270 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2271 if (!sm_cmac_ready()) break; 2272 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2273 h6_calculate_br_edr_link_key(connection); 2274 break; 2275 #endif 2276 2277 #ifdef ENABLE_LE_CENTRAL 2278 // initiator side 2279 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2280 sm_key_t peer_ltk_flipped; 2281 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2282 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2283 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2284 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2285 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2286 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2287 return; 2288 } 2289 2290 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2291 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2292 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2293 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2294 sm_timeout_reset(connection); 2295 break; 2296 #endif 2297 2298 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2299 2300 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2301 int trigger_user_response = 0; 2302 int trigger_start_calculating_local_confirm = 0; 2303 uint8_t buffer[65]; 2304 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2305 // 2306 reverse_256(&ec_q[0], &buffer[1]); 2307 reverse_256(&ec_q[32], &buffer[33]); 2308 2309 #ifdef ENABLE_TESTING_SUPPORT 2310 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2311 log_info("testing_support: invalidating public key"); 2312 // flip single bit of public key coordinate 2313 buffer[1] ^= 1; 2314 } 2315 #endif 2316 2317 // stk generation method 2318 // passkey entry: notify app to show passkey or to request passkey 2319 switch (setup->sm_stk_generation_method){ 2320 case JUST_WORKS: 2321 case NUMERIC_COMPARISON: 2322 if (IS_RESPONDER(connection->sm_role)){ 2323 // responder 2324 trigger_start_calculating_local_confirm = 1; 2325 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2326 } else { 2327 // initiator 2328 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2329 } 2330 break; 2331 case PK_INIT_INPUT: 2332 case PK_RESP_INPUT: 2333 case PK_BOTH_INPUT: 2334 // use random TK for display 2335 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2336 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2337 setup->sm_passkey_bit = 0; 2338 2339 if (IS_RESPONDER(connection->sm_role)){ 2340 // responder 2341 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2342 } else { 2343 // initiator 2344 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2345 } 2346 trigger_user_response = 1; 2347 break; 2348 case OOB: 2349 if (IS_RESPONDER(connection->sm_role)){ 2350 // responder 2351 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2352 } else { 2353 // initiator 2354 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2355 } 2356 break; 2357 } 2358 2359 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2360 sm_timeout_reset(connection); 2361 2362 // trigger user response and calc confirm after sending pdu 2363 if (trigger_user_response){ 2364 sm_trigger_user_response(connection); 2365 } 2366 if (trigger_start_calculating_local_confirm){ 2367 sm_sc_start_calculating_local_confirm(connection); 2368 } 2369 break; 2370 } 2371 case SM_SC_SEND_CONFIRMATION: { 2372 uint8_t buffer[17]; 2373 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2374 reverse_128(setup->sm_local_confirm, &buffer[1]); 2375 if (IS_RESPONDER(connection->sm_role)){ 2376 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2377 } else { 2378 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2379 } 2380 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2381 sm_timeout_reset(connection); 2382 break; 2383 } 2384 case SM_SC_SEND_PAIRING_RANDOM: { 2385 uint8_t buffer[17]; 2386 buffer[0] = SM_CODE_PAIRING_RANDOM; 2387 reverse_128(setup->sm_local_nonce, &buffer[1]); 2388 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2389 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20)){ 2390 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2391 if (IS_RESPONDER(connection->sm_role)){ 2392 // responder 2393 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2394 } else { 2395 // initiator 2396 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2397 } 2398 } else { 2399 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2400 if (IS_RESPONDER(connection->sm_role)){ 2401 // responder 2402 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2403 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2404 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2405 } else { 2406 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2407 sm_sc_prepare_dhkey_check(connection); 2408 } 2409 } else { 2410 // initiator 2411 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2412 } 2413 } 2414 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2415 sm_timeout_reset(connection); 2416 break; 2417 } 2418 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2419 uint8_t buffer[17]; 2420 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2421 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2422 2423 if (IS_RESPONDER(connection->sm_role)){ 2424 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2425 } else { 2426 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2427 } 2428 2429 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2430 sm_timeout_reset(connection); 2431 break; 2432 } 2433 2434 #endif 2435 2436 #ifdef ENABLE_LE_PERIPHERAL 2437 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2438 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2439 2440 // start with initiator key dist flags 2441 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2442 2443 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2444 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2445 if (setup->sm_use_secure_connections){ 2446 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2447 } 2448 #endif 2449 // setup in response 2450 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); 2451 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); 2452 2453 // update key distribution after ENC was dropped 2454 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2455 2456 if (setup->sm_use_secure_connections){ 2457 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2458 } else { 2459 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2460 } 2461 2462 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2463 sm_timeout_reset(connection); 2464 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2465 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2466 sm_trigger_user_response(connection); 2467 } 2468 return; 2469 #endif 2470 2471 case SM_PH2_SEND_PAIRING_RANDOM: { 2472 uint8_t buffer[17]; 2473 buffer[0] = SM_CODE_PAIRING_RANDOM; 2474 reverse_128(setup->sm_local_random, &buffer[1]); 2475 if (IS_RESPONDER(connection->sm_role)){ 2476 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2477 } else { 2478 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2479 } 2480 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2481 sm_timeout_reset(connection); 2482 break; 2483 } 2484 2485 case SM_PH2_C1_GET_ENC_A: 2486 // already busy? 2487 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2488 // calculate confirm using aes128 engine - step 1 2489 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); 2490 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2491 sm_aes128_state = SM_AES128_ACTIVE; 2492 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, (void *)(uintptr_t) connection->sm_handle); 2493 break; 2494 2495 case SM_PH2_C1_GET_ENC_C: 2496 // already busy? 2497 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2498 // calculate m_confirm using aes128 engine - step 1 2499 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); 2500 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2501 sm_aes128_state = SM_AES128_ACTIVE; 2502 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, (void *)(uintptr_t) connection->sm_handle); 2503 break; 2504 2505 case SM_PH2_CALC_STK: 2506 // already busy? 2507 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2508 // calculate STK 2509 if (IS_RESPONDER(connection->sm_role)){ 2510 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2511 } else { 2512 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2513 } 2514 connection->sm_engine_state = SM_PH2_W4_STK; 2515 sm_aes128_state = SM_AES128_ACTIVE; 2516 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2517 break; 2518 2519 case SM_PH3_Y_GET_ENC: 2520 // already busy? 2521 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2522 // PH3B2 - calculate Y from - enc 2523 2524 // dm helper (was sm_dm_r_prime) 2525 // r' = padding || r 2526 // r - 64 bit value 2527 memset(&sm_aes128_plaintext[0], 0, 8); 2528 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2529 2530 // Y = dm(DHK, Rand) 2531 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2532 sm_aes128_state = SM_AES128_ACTIVE; 2533 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, (void *)(uintptr_t) connection->sm_handle); 2534 break; 2535 2536 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2537 uint8_t buffer[17]; 2538 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2539 reverse_128(setup->sm_local_confirm, &buffer[1]); 2540 if (IS_RESPONDER(connection->sm_role)){ 2541 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2542 } else { 2543 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2544 } 2545 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2546 sm_timeout_reset(connection); 2547 return; 2548 } 2549 #ifdef ENABLE_LE_PERIPHERAL 2550 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2551 sm_key_t stk_flipped; 2552 reverse_128(setup->sm_ltk, stk_flipped); 2553 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2554 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2555 return; 2556 } 2557 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2558 sm_key_t ltk_flipped; 2559 reverse_128(setup->sm_ltk, ltk_flipped); 2560 connection->sm_engine_state = SM_RESPONDER_IDLE; 2561 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2562 sm_done_for_handle(connection->sm_handle); 2563 return; 2564 } 2565 case SM_RESPONDER_PH4_Y_GET_ENC: 2566 // already busy? 2567 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2568 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2569 2570 // dm helper (was sm_dm_r_prime) 2571 // r' = padding || r 2572 // r - 64 bit value 2573 memset(&sm_aes128_plaintext[0], 0, 8); 2574 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2575 2576 // Y = dm(DHK, Rand) 2577 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2578 sm_aes128_state = SM_AES128_ACTIVE; 2579 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, (void *)(uintptr_t) connection->sm_handle); 2580 return; 2581 #endif 2582 #ifdef ENABLE_LE_CENTRAL 2583 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2584 sm_key_t stk_flipped; 2585 reverse_128(setup->sm_ltk, stk_flipped); 2586 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2587 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2588 return; 2589 } 2590 #endif 2591 2592 case SM_PH3_DISTRIBUTE_KEYS: 2593 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2594 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2595 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2596 uint8_t buffer[17]; 2597 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2598 reverse_128(setup->sm_ltk, &buffer[1]); 2599 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2600 sm_timeout_reset(connection); 2601 return; 2602 } 2603 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2604 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2605 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2606 uint8_t buffer[11]; 2607 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2608 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2609 reverse_64(setup->sm_local_rand, &buffer[3]); 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_IDENTITY_INFORMATION){ 2615 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2616 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2617 uint8_t buffer[17]; 2618 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2619 reverse_128(sm_persistent_irk, &buffer[1]); 2620 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2621 sm_timeout_reset(connection); 2622 return; 2623 } 2624 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2625 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2626 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2627 bd_addr_t local_address; 2628 uint8_t buffer[8]; 2629 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2630 switch (gap_random_address_get_mode()){ 2631 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2632 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2633 // public or static random 2634 gap_le_get_own_address(&buffer[1], local_address); 2635 break; 2636 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2637 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2638 // fallback to public 2639 gap_local_bd_addr(local_address); 2640 buffer[1] = 0; 2641 break; 2642 } 2643 reverse_bd_addr(local_address, &buffer[2]); 2644 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2645 sm_timeout_reset(connection); 2646 return; 2647 } 2648 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2649 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2650 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2651 2652 #ifdef ENABLE_LE_SIGNED_WRITE 2653 // hack to reproduce test runs 2654 if (test_use_fixed_local_csrk){ 2655 memset(setup->sm_local_csrk, 0xcc, 16); 2656 } 2657 2658 // store local CSRK 2659 if (setup->sm_le_device_index >= 0){ 2660 log_info("sm: store local CSRK"); 2661 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2662 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2663 } 2664 #endif 2665 2666 uint8_t buffer[17]; 2667 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2668 reverse_128(setup->sm_local_csrk, &buffer[1]); 2669 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2670 sm_timeout_reset(connection); 2671 return; 2672 } 2673 2674 // keys are sent 2675 if (IS_RESPONDER(connection->sm_role)){ 2676 // slave -> receive master keys if any 2677 if (sm_key_distribution_all_received(connection)){ 2678 sm_key_distribution_handle_all_received(connection); 2679 connection->sm_engine_state = SM_RESPONDER_IDLE; 2680 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2681 sm_done_for_handle(connection->sm_handle); 2682 } else { 2683 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2684 } 2685 } else { 2686 sm_master_pairing_success(connection); 2687 } 2688 break; 2689 2690 default: 2691 break; 2692 } 2693 2694 // check again if active connection was released 2695 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2696 } 2697 } 2698 2699 // sm_aes128_state stays active 2700 static void sm_handle_encryption_result_enc_a(void *arg){ 2701 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2702 sm_aes128_state = SM_AES128_IDLE; 2703 2704 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2705 if (connection == NULL) return; 2706 2707 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2708 sm_aes128_state = SM_AES128_ACTIVE; 2709 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, (void *)(uintptr_t) connection->sm_handle); 2710 } 2711 2712 static void sm_handle_encryption_result_enc_b(void *arg){ 2713 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2714 sm_aes128_state = SM_AES128_IDLE; 2715 2716 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2717 if (connection == NULL) return; 2718 2719 log_info_key("c1!", setup->sm_local_confirm); 2720 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2721 sm_run(); 2722 } 2723 2724 // sm_aes128_state stays active 2725 static void sm_handle_encryption_result_enc_c(void *arg){ 2726 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2727 sm_aes128_state = SM_AES128_IDLE; 2728 2729 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2730 if (connection == NULL) return; 2731 2732 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2733 sm_aes128_state = SM_AES128_ACTIVE; 2734 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, (void *)(uintptr_t) connection->sm_handle); 2735 } 2736 2737 static void sm_handle_encryption_result_enc_d(void * arg){ 2738 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2739 sm_aes128_state = SM_AES128_IDLE; 2740 2741 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2742 if (connection == NULL) return; 2743 2744 log_info_key("c1!", sm_aes128_ciphertext); 2745 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2746 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2747 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2748 sm_run(); 2749 return; 2750 } 2751 if (IS_RESPONDER(connection->sm_role)){ 2752 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2753 sm_run(); 2754 } else { 2755 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2756 sm_aes128_state = SM_AES128_ACTIVE; 2757 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2758 } 2759 } 2760 2761 static void sm_handle_encryption_result_enc_stk(void *arg){ 2762 sm_aes128_state = SM_AES128_IDLE; 2763 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2764 2765 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2766 if (connection == NULL) return; 2767 2768 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2769 log_info_key("stk", setup->sm_ltk); 2770 if (IS_RESPONDER(connection->sm_role)){ 2771 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2772 } else { 2773 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2774 } 2775 sm_run(); 2776 } 2777 2778 // sm_aes128_state stays active 2779 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2780 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2781 sm_aes128_state = SM_AES128_IDLE; 2782 2783 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2784 if (connection == NULL) return; 2785 2786 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2787 log_info_hex16("y", setup->sm_local_y); 2788 // PH3B3 - calculate EDIV 2789 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2790 log_info_hex16("ediv", setup->sm_local_ediv); 2791 // PH3B4 - calculate LTK - enc 2792 // LTK = d1(ER, DIV, 0)) 2793 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2794 sm_aes128_state = SM_AES128_ACTIVE; 2795 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); 2796 } 2797 2798 #ifdef ENABLE_LE_PERIPHERAL 2799 // sm_aes128_state stays active 2800 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2801 sm_aes128_state = SM_AES128_IDLE; 2802 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2803 2804 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2805 if (connection == NULL) return; 2806 2807 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2808 log_info_hex16("y", setup->sm_local_y); 2809 2810 // PH3B3 - calculate DIV 2811 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2812 log_info_hex16("ediv", setup->sm_local_ediv); 2813 // PH3B4 - calculate LTK - enc 2814 // LTK = d1(ER, DIV, 0)) 2815 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2816 sm_aes128_state = SM_AES128_ACTIVE; 2817 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, (void *)(uintptr_t) connection->sm_handle); 2818 } 2819 #endif 2820 2821 // sm_aes128_state stays active 2822 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2823 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2824 sm_aes128_state = SM_AES128_IDLE; 2825 2826 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2827 if (connection == NULL) return; 2828 2829 log_info_key("ltk", setup->sm_ltk); 2830 // calc CSRK next 2831 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2832 sm_aes128_state = SM_AES128_ACTIVE; 2833 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); 2834 } 2835 2836 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2837 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2838 sm_aes128_state = SM_AES128_IDLE; 2839 2840 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2841 if (connection == NULL) return; 2842 2843 sm_aes128_state = SM_AES128_IDLE; 2844 log_info_key("csrk", setup->sm_local_csrk); 2845 if (setup->sm_key_distribution_send_set){ 2846 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2847 } else { 2848 // no keys to send, just continue 2849 if (IS_RESPONDER(connection->sm_role)){ 2850 // slave -> receive master keys 2851 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2852 } else { 2853 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2854 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2855 } else { 2856 sm_master_pairing_success(connection); 2857 } 2858 } 2859 } 2860 sm_run(); 2861 } 2862 2863 #ifdef ENABLE_LE_PERIPHERAL 2864 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2865 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2866 sm_aes128_state = SM_AES128_IDLE; 2867 2868 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2869 if (connection == NULL) return; 2870 2871 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2872 log_info_key("ltk", setup->sm_ltk); 2873 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2874 sm_run(); 2875 } 2876 #endif 2877 2878 static void sm_handle_encryption_result_address_resolution(void *arg){ 2879 UNUSED(arg); 2880 sm_aes128_state = SM_AES128_IDLE; 2881 2882 sm_address_resolution_ah_calculation_active = 0; 2883 // compare calulated address against connecting device 2884 uint8_t * hash = &sm_aes128_ciphertext[13]; 2885 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2886 log_info("LE Device Lookup: matched resolvable private address"); 2887 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2888 sm_run(); 2889 return; 2890 } 2891 // no match, try next 2892 sm_address_resolution_test++; 2893 sm_run(); 2894 } 2895 2896 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2897 UNUSED(arg); 2898 sm_aes128_state = SM_AES128_IDLE; 2899 2900 log_info_key("irk", sm_persistent_irk); 2901 dkg_state = DKG_CALC_DHK; 2902 sm_run(); 2903 } 2904 2905 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2906 UNUSED(arg); 2907 sm_aes128_state = SM_AES128_IDLE; 2908 2909 log_info_key("dhk", sm_persistent_dhk); 2910 dkg_state = DKG_READY; 2911 sm_run(); 2912 } 2913 2914 static void sm_handle_encryption_result_rau(void *arg){ 2915 UNUSED(arg); 2916 sm_aes128_state = SM_AES128_IDLE; 2917 2918 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2919 rau_state = RAU_SET_ADDRESS; 2920 sm_run(); 2921 } 2922 2923 static void sm_handle_random_result_rau(void * arg){ 2924 UNUSED(arg); 2925 // non-resolvable vs. resolvable 2926 switch (gap_random_adress_type){ 2927 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2928 // resolvable: use random as prand and calc address hash 2929 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2930 sm_random_address[0] &= 0x3f; 2931 sm_random_address[0] |= 0x40; 2932 rau_state = RAU_GET_ENC; 2933 break; 2934 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2935 default: 2936 // "The two most significant bits of the address shall be equal to ‘0’"" 2937 sm_random_address[0] &= 0x3f; 2938 rau_state = RAU_SET_ADDRESS; 2939 break; 2940 } 2941 sm_run(); 2942 } 2943 2944 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2945 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 2946 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2947 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2948 if (connection == NULL) return; 2949 2950 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2951 sm_run(); 2952 } 2953 2954 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 2955 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2956 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2957 if (connection == NULL) return; 2958 2959 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2960 sm_run(); 2961 } 2962 #endif 2963 2964 static void sm_handle_random_result_ph2_random(void * arg){ 2965 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2966 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2967 if (connection == NULL) return; 2968 2969 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2970 sm_run(); 2971 } 2972 2973 static void sm_handle_random_result_ph2_tk(void * arg){ 2974 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2975 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2976 if (connection == NULL) return; 2977 2978 sm_reset_tk(); 2979 uint32_t tk; 2980 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2981 // map random to 0-999999 without speding much cycles on a modulus operation 2982 tk = little_endian_read_32(sm_random_data,0); 2983 tk = tk & 0xfffff; // 1048575 2984 if (tk >= 999999){ 2985 tk = tk - 999999; 2986 } 2987 } else { 2988 // override with pre-defined passkey 2989 tk = sm_fixed_passkey_in_display_role; 2990 } 2991 big_endian_store_32(setup->sm_tk, 12, tk); 2992 if (IS_RESPONDER(connection->sm_role)){ 2993 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2994 } else { 2995 if (setup->sm_use_secure_connections){ 2996 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2997 } else { 2998 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2999 sm_trigger_user_response(connection); 3000 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3001 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3002 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) connection->sm_handle); 3003 } 3004 } 3005 } 3006 sm_run(); 3007 } 3008 3009 static void sm_handle_random_result_ph3_div(void * arg){ 3010 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3011 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3012 if (connection == NULL) return; 3013 3014 // use 16 bit from random value as div 3015 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3016 log_info_hex16("div", setup->sm_local_div); 3017 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3018 sm_run(); 3019 } 3020 3021 static void sm_handle_random_result_ph3_random(void * arg){ 3022 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3023 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3024 if (connection == NULL) return; 3025 3026 reverse_64(sm_random_data, setup->sm_local_rand); 3027 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3028 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 3029 // no db for authenticated flag hack: store flag in bit 4 of LSB 3030 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 3031 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3032 } 3033 static void sm_validate_er_ir(void){ 3034 // warn about default ER/IR 3035 int warning = 0; 3036 if (sm_ir_is_default()){ 3037 warning = 1; 3038 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3039 } 3040 if (sm_er_is_default()){ 3041 warning = 1; 3042 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3043 } 3044 if (warning) { 3045 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3046 } 3047 } 3048 3049 static void sm_handle_random_result_ir(void *arg){ 3050 sm_persistent_keys_random_active = 0; 3051 if (arg){ 3052 // key generated, store in tlv 3053 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3054 log_info("Generated IR key. Store in TLV status: %d", status); 3055 } 3056 log_info_key("IR", sm_persistent_ir); 3057 dkg_state = DKG_CALC_IRK; 3058 3059 if (test_use_fixed_local_irk){ 3060 log_info_key("IRK", sm_persistent_irk); 3061 dkg_state = DKG_CALC_DHK; 3062 } 3063 3064 sm_run(); 3065 } 3066 3067 static void sm_handle_random_result_er(void *arg){ 3068 sm_persistent_keys_random_active = 0; 3069 if (arg){ 3070 // key generated, store in tlv 3071 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3072 log_info("Generated ER key. Store in TLV status: %d", status); 3073 } 3074 log_info_key("ER", sm_persistent_er); 3075 3076 // try load ir 3077 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3078 if (key_size == 16){ 3079 // ok, let's continue 3080 log_info("IR from TLV"); 3081 sm_handle_random_result_ir( NULL ); 3082 } else { 3083 // invalid, generate new random one 3084 sm_persistent_keys_random_active = 1; 3085 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3086 } 3087 } 3088 3089 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3090 3091 UNUSED(channel); // ok: there is no channel 3092 UNUSED(size); // ok: fixed format HCI events 3093 3094 sm_connection_t * sm_conn; 3095 hci_con_handle_t con_handle; 3096 3097 switch (packet_type) { 3098 3099 case HCI_EVENT_PACKET: 3100 switch (hci_event_packet_get_type(packet)) { 3101 3102 case BTSTACK_EVENT_STATE: 3103 // bt stack activated, get started 3104 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3105 log_info("HCI Working!"); 3106 3107 // setup IR/ER with TLV 3108 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3109 if (sm_tlv_impl){ 3110 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3111 if (key_size == 16){ 3112 // ok, let's continue 3113 log_info("ER from TLV"); 3114 sm_handle_random_result_er( NULL ); 3115 } else { 3116 // invalid, generate random one 3117 sm_persistent_keys_random_active = 1; 3118 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3119 } 3120 } else { 3121 sm_validate_er_ir(); 3122 dkg_state = DKG_CALC_IRK; 3123 3124 if (test_use_fixed_local_irk){ 3125 log_info_key("IRK", sm_persistent_irk); 3126 dkg_state = DKG_CALC_DHK; 3127 } 3128 } 3129 3130 // restart random address updates after power cycle 3131 gap_random_address_set_mode(gap_random_adress_type); 3132 } 3133 break; 3134 3135 case HCI_EVENT_LE_META: 3136 switch (packet[2]) { 3137 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3138 3139 log_info("sm: connected"); 3140 3141 if (packet[3]) return; // connection failed 3142 3143 con_handle = little_endian_read_16(packet, 4); 3144 sm_conn = sm_get_connection_for_handle(con_handle); 3145 if (!sm_conn) break; 3146 3147 sm_conn->sm_handle = con_handle; 3148 sm_conn->sm_role = packet[6]; 3149 sm_conn->sm_peer_addr_type = packet[7]; 3150 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3151 3152 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3153 3154 // reset security properties 3155 sm_conn->sm_connection_encrypted = 0; 3156 sm_conn->sm_connection_authenticated = 0; 3157 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3158 sm_conn->sm_le_db_index = -1; 3159 3160 // prepare CSRK lookup (does not involve setup) 3161 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3162 3163 // just connected -> everything else happens in sm_run() 3164 if (IS_RESPONDER(sm_conn->sm_role)){ 3165 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3166 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3167 if (sm_slave_request_security) { 3168 // request security if requested by app 3169 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3170 } else { 3171 // otherwise, wait for pairing request 3172 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3173 } 3174 } 3175 break; 3176 } else { 3177 // master 3178 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3179 } 3180 break; 3181 3182 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3183 con_handle = little_endian_read_16(packet, 3); 3184 sm_conn = sm_get_connection_for_handle(con_handle); 3185 if (!sm_conn) break; 3186 3187 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3188 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3189 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3190 break; 3191 } 3192 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3193 // PH2 SEND LTK as we need to exchange keys in PH3 3194 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3195 break; 3196 } 3197 3198 // store rand and ediv 3199 reverse_64(&packet[5], sm_conn->sm_local_rand); 3200 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3201 3202 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3203 // potentially stored LTK is from the master 3204 if ((sm_conn->sm_local_ediv != 0) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3205 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3206 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3207 break; 3208 } 3209 // additionally check if remote is in LE Device DB if requested 3210 switch(sm_conn->sm_irk_lookup_state){ 3211 case IRK_LOOKUP_FAILED: 3212 log_info("LTK Request: device not in device db"); 3213 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3214 break; 3215 case IRK_LOOKUP_SUCCEEDED: 3216 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3217 break; 3218 default: 3219 // wait for irk look doen 3220 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3221 break; 3222 } 3223 break; 3224 } 3225 3226 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3227 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3228 #else 3229 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3230 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3231 #endif 3232 break; 3233 3234 default: 3235 break; 3236 } 3237 break; 3238 3239 case HCI_EVENT_ENCRYPTION_CHANGE: 3240 con_handle = little_endian_read_16(packet, 3); 3241 sm_conn = sm_get_connection_for_handle(con_handle); 3242 if (!sm_conn) break; 3243 3244 sm_conn->sm_connection_encrypted = packet[5]; 3245 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3246 sm_conn->sm_actual_encryption_key_size); 3247 log_info("event handler, state %u", sm_conn->sm_engine_state); 3248 3249 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3250 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3251 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3252 // notify client, if pairing was requested before 3253 if (sm_conn->sm_pairing_requested){ 3254 sm_conn->sm_pairing_requested = 0; 3255 if (sm_conn->sm_connection_encrypted){ 3256 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3257 } else { 3258 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3259 } 3260 } 3261 sm_done_for_handle(sm_conn->sm_handle); 3262 break; 3263 } 3264 3265 if (!sm_conn->sm_connection_encrypted) break; 3266 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3267 3268 // continue pairing 3269 switch (sm_conn->sm_engine_state){ 3270 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3271 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3272 sm_done_for_handle(sm_conn->sm_handle); 3273 break; 3274 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3275 if (IS_RESPONDER(sm_conn->sm_role)){ 3276 // slave 3277 if (setup->sm_use_secure_connections){ 3278 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3279 } else { 3280 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3281 } 3282 } else { 3283 // master 3284 if (sm_key_distribution_all_received(sm_conn)){ 3285 // skip receiving keys as there are none 3286 sm_key_distribution_handle_all_received(sm_conn); 3287 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3288 } else { 3289 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3290 } 3291 } 3292 break; 3293 default: 3294 break; 3295 } 3296 break; 3297 3298 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3299 con_handle = little_endian_read_16(packet, 3); 3300 sm_conn = sm_get_connection_for_handle(con_handle); 3301 if (!sm_conn) break; 3302 3303 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3304 log_info("event handler, state %u", sm_conn->sm_engine_state); 3305 // continue if part of initial pairing 3306 switch (sm_conn->sm_engine_state){ 3307 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3308 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3309 sm_done_for_handle(sm_conn->sm_handle); 3310 break; 3311 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3312 if (IS_RESPONDER(sm_conn->sm_role)){ 3313 // slave 3314 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3315 } else { 3316 // master 3317 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3318 } 3319 break; 3320 default: 3321 break; 3322 } 3323 break; 3324 3325 3326 case HCI_EVENT_DISCONNECTION_COMPLETE: 3327 con_handle = little_endian_read_16(packet, 3); 3328 sm_done_for_handle(con_handle); 3329 sm_conn = sm_get_connection_for_handle(con_handle); 3330 if (!sm_conn) break; 3331 3332 // delete stored bonding on disconnect with authentication failure in ph0 3333 if ((sm_conn->sm_role == 0) 3334 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3335 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3336 le_device_db_remove(sm_conn->sm_le_db_index); 3337 } 3338 3339 // pairing failed, if it was ongoing 3340 switch (sm_conn->sm_engine_state){ 3341 case SM_GENERAL_IDLE: 3342 case SM_INITIATOR_CONNECTED: 3343 case SM_RESPONDER_IDLE: 3344 break; 3345 default: 3346 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3347 break; 3348 } 3349 3350 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3351 sm_conn->sm_handle = 0; 3352 break; 3353 3354 case HCI_EVENT_COMMAND_COMPLETE: 3355 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3356 // set local addr for le device db 3357 bd_addr_t addr; 3358 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3359 le_device_db_set_local_bd_addr(addr); 3360 } 3361 break; 3362 default: 3363 break; 3364 } 3365 break; 3366 default: 3367 break; 3368 } 3369 3370 sm_run(); 3371 } 3372 3373 static inline int sm_calc_actual_encryption_key_size(int other){ 3374 if (other < sm_min_encryption_key_size) return 0; 3375 if (other < sm_max_encryption_key_size) return other; 3376 return sm_max_encryption_key_size; 3377 } 3378 3379 3380 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3381 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3382 switch (method){ 3383 case JUST_WORKS: 3384 case NUMERIC_COMPARISON: 3385 return 1; 3386 default: 3387 return 0; 3388 } 3389 } 3390 // responder 3391 3392 static int sm_passkey_used(stk_generation_method_t method){ 3393 switch (method){ 3394 case PK_RESP_INPUT: 3395 return 1; 3396 default: 3397 return 0; 3398 } 3399 } 3400 3401 static int sm_passkey_entry(stk_generation_method_t method){ 3402 switch (method){ 3403 case PK_RESP_INPUT: 3404 case PK_INIT_INPUT: 3405 case PK_BOTH_INPUT: 3406 return 1; 3407 default: 3408 return 0; 3409 } 3410 } 3411 3412 #endif 3413 3414 /** 3415 * @return ok 3416 */ 3417 static int sm_validate_stk_generation_method(void){ 3418 // check if STK generation method is acceptable by client 3419 switch (setup->sm_stk_generation_method){ 3420 case JUST_WORKS: 3421 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3422 case PK_RESP_INPUT: 3423 case PK_INIT_INPUT: 3424 case PK_BOTH_INPUT: 3425 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3426 case OOB: 3427 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3428 case NUMERIC_COMPARISON: 3429 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3430 default: 3431 return 0; 3432 } 3433 } 3434 3435 // size of complete sm_pdu used to validate input 3436 static const uint8_t sm_pdu_size[] = { 3437 0, // 0x00 invalid opcode 3438 7, // 0x01 pairing request 3439 7, // 0x02 pairing response 3440 17, // 0x03 pairing confirm 3441 17, // 0x04 pairing random 3442 2, // 0x05 pairing failed 3443 17, // 0x06 encryption information 3444 11, // 0x07 master identification 3445 17, // 0x08 identification information 3446 8, // 0x09 identify address information 3447 17, // 0x0a signing information 3448 2, // 0x0b security request 3449 65, // 0x0c pairing public key 3450 17, // 0x0d pairing dhk check 3451 2, // 0x0e keypress notification 3452 }; 3453 3454 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3455 3456 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3457 sm_run(); 3458 } 3459 3460 if (packet_type != SM_DATA_PACKET) return; 3461 if (size == 0) return; 3462 3463 uint8_t sm_pdu_code = packet[0]; 3464 3465 // validate pdu size 3466 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3467 if (sm_pdu_size[sm_pdu_code] != size) return; 3468 3469 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3470 if (!sm_conn) return; 3471 3472 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3473 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3474 sm_done_for_handle(con_handle); 3475 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3476 return; 3477 } 3478 3479 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3480 3481 int err; 3482 UNUSED(err); 3483 3484 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3485 uint8_t buffer[5]; 3486 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3487 buffer[1] = 3; 3488 little_endian_store_16(buffer, 2, con_handle); 3489 buffer[4] = packet[1]; 3490 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3491 return; 3492 } 3493 3494 switch (sm_conn->sm_engine_state){ 3495 3496 // a sm timeout requries a new physical connection 3497 case SM_GENERAL_TIMEOUT: 3498 return; 3499 3500 #ifdef ENABLE_LE_CENTRAL 3501 3502 // Initiator 3503 case SM_INITIATOR_CONNECTED: 3504 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3505 sm_pdu_received_in_wrong_state(sm_conn); 3506 break; 3507 } 3508 3509 // IRK complete? 3510 int have_ltk; 3511 uint8_t ltk[16]; 3512 switch (sm_conn->sm_irk_lookup_state){ 3513 case IRK_LOOKUP_FAILED: 3514 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3515 break; 3516 case IRK_LOOKUP_SUCCEEDED: 3517 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3518 have_ltk = !sm_is_null_key(ltk); 3519 log_info("central: security request - have_ltk %u", have_ltk); 3520 if (have_ltk){ 3521 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3522 } else { 3523 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3524 } 3525 break; 3526 default: 3527 break; 3528 } 3529 3530 // otherwise, store security request 3531 sm_conn->sm_security_request_received = 1; 3532 break; 3533 3534 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3535 // Core 5, Vol 3, Part H, 2.4.6: 3536 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3537 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3538 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3539 log_info("Ignoring Security Request"); 3540 break; 3541 } 3542 3543 // all other pdus are incorrect 3544 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3545 sm_pdu_received_in_wrong_state(sm_conn); 3546 break; 3547 } 3548 3549 // store pairing request 3550 (void)memcpy(&setup->sm_s_pres, packet, 3551 sizeof(sm_pairing_packet_t)); 3552 err = sm_stk_generation_init(sm_conn); 3553 3554 #ifdef ENABLE_TESTING_SUPPORT 3555 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3556 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3557 err = test_pairing_failure; 3558 } 3559 #endif 3560 3561 if (err){ 3562 setup->sm_pairing_failed_reason = err; 3563 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3564 break; 3565 } 3566 3567 // generate random number first, if we need to show passkey 3568 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3569 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_conn->sm_handle); 3570 break; 3571 } 3572 3573 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3574 if (setup->sm_use_secure_connections){ 3575 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3576 if (setup->sm_stk_generation_method == JUST_WORKS){ 3577 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3578 sm_trigger_user_response(sm_conn); 3579 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3580 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3581 } 3582 } else { 3583 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3584 } 3585 break; 3586 } 3587 #endif 3588 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3589 sm_trigger_user_response(sm_conn); 3590 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3591 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3592 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3593 } 3594 break; 3595 3596 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3597 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3598 sm_pdu_received_in_wrong_state(sm_conn); 3599 break; 3600 } 3601 3602 // store s_confirm 3603 reverse_128(&packet[1], setup->sm_peer_confirm); 3604 3605 #ifdef ENABLE_TESTING_SUPPORT 3606 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3607 log_info("testing_support: reset confirm value"); 3608 memset(setup->sm_peer_confirm, 0, 16); 3609 } 3610 #endif 3611 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3612 break; 3613 3614 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3615 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3616 sm_pdu_received_in_wrong_state(sm_conn); 3617 break;; 3618 } 3619 3620 // received random value 3621 reverse_128(&packet[1], setup->sm_peer_random); 3622 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3623 break; 3624 #endif 3625 3626 #ifdef ENABLE_LE_PERIPHERAL 3627 // Responder 3628 case SM_RESPONDER_IDLE: 3629 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3630 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3631 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3632 sm_pdu_received_in_wrong_state(sm_conn); 3633 break;; 3634 } 3635 3636 // store pairing request 3637 (void)memcpy(&sm_conn->sm_m_preq, packet, 3638 sizeof(sm_pairing_packet_t)); 3639 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3640 break; 3641 #endif 3642 3643 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3644 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3645 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3646 sm_pdu_received_in_wrong_state(sm_conn); 3647 break; 3648 } 3649 3650 // store public key for DH Key calculation 3651 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3652 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3653 3654 // validate public key 3655 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3656 if (err){ 3657 log_error("sm: peer public key invalid %x", err); 3658 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3659 break; 3660 } 3661 3662 // start calculating dhkey 3663 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, (void*)(uintptr_t) sm_conn->sm_handle); 3664 3665 3666 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3667 if (IS_RESPONDER(sm_conn->sm_role)){ 3668 // responder 3669 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3670 } else { 3671 // initiator 3672 // stk generation method 3673 // passkey entry: notify app to show passkey or to request passkey 3674 switch (setup->sm_stk_generation_method){ 3675 case JUST_WORKS: 3676 case NUMERIC_COMPARISON: 3677 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3678 break; 3679 case PK_RESP_INPUT: 3680 sm_sc_start_calculating_local_confirm(sm_conn); 3681 break; 3682 case PK_INIT_INPUT: 3683 case PK_BOTH_INPUT: 3684 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3685 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3686 break; 3687 } 3688 sm_sc_start_calculating_local_confirm(sm_conn); 3689 break; 3690 case OOB: 3691 // generate Nx 3692 log_info("Generate Na"); 3693 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3694 break; 3695 } 3696 } 3697 break; 3698 3699 case SM_SC_W4_CONFIRMATION: 3700 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3701 sm_pdu_received_in_wrong_state(sm_conn); 3702 break; 3703 } 3704 // received confirm value 3705 reverse_128(&packet[1], setup->sm_peer_confirm); 3706 3707 #ifdef ENABLE_TESTING_SUPPORT 3708 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3709 log_info("testing_support: reset confirm value"); 3710 memset(setup->sm_peer_confirm, 0, 16); 3711 } 3712 #endif 3713 if (IS_RESPONDER(sm_conn->sm_role)){ 3714 // responder 3715 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3716 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3717 // still waiting for passkey 3718 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3719 break; 3720 } 3721 } 3722 sm_sc_start_calculating_local_confirm(sm_conn); 3723 } else { 3724 // initiator 3725 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3726 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3727 } else { 3728 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3729 } 3730 } 3731 break; 3732 3733 case SM_SC_W4_PAIRING_RANDOM: 3734 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3735 sm_pdu_received_in_wrong_state(sm_conn); 3736 break; 3737 } 3738 3739 // received random value 3740 reverse_128(&packet[1], setup->sm_peer_nonce); 3741 3742 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3743 // only check for JUST WORK/NC in initiator role OR passkey entry 3744 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3745 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3746 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3747 break; 3748 } 3749 3750 // OOB 3751 if (setup->sm_stk_generation_method == OOB){ 3752 3753 // setup local random, set to zero if remote did not receive our data 3754 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3755 if (IS_RESPONDER(sm_conn->sm_role)){ 3756 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3757 log_info("Reset rb as A does not have OOB data"); 3758 memset(setup->sm_rb, 0, 16); 3759 } else { 3760 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3761 log_info("Use stored rb"); 3762 log_info_hexdump(setup->sm_rb, 16); 3763 } 3764 } else { 3765 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3766 log_info("Reset ra as B does not have OOB data"); 3767 memset(setup->sm_ra, 0, 16); 3768 } else { 3769 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3770 log_info("Use stored ra"); 3771 log_info_hexdump(setup->sm_ra, 16); 3772 } 3773 } 3774 3775 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3776 if (setup->sm_have_oob_data){ 3777 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3778 break; 3779 } 3780 } 3781 3782 // TODO: we only get here for Responder role with JW/NC 3783 sm_sc_state_after_receiving_random(sm_conn); 3784 break; 3785 3786 case SM_SC_W2_CALCULATE_G2: 3787 case SM_SC_W4_CALCULATE_G2: 3788 case SM_SC_W4_CALCULATE_DHKEY: 3789 case SM_SC_W2_CALCULATE_F5_SALT: 3790 case SM_SC_W4_CALCULATE_F5_SALT: 3791 case SM_SC_W2_CALCULATE_F5_MACKEY: 3792 case SM_SC_W4_CALCULATE_F5_MACKEY: 3793 case SM_SC_W2_CALCULATE_F5_LTK: 3794 case SM_SC_W4_CALCULATE_F5_LTK: 3795 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3796 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3797 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3798 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3799 sm_pdu_received_in_wrong_state(sm_conn); 3800 break; 3801 } 3802 // store DHKey Check 3803 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3804 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3805 3806 // have we been only waiting for dhkey check command? 3807 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3808 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3809 } 3810 break; 3811 #endif 3812 3813 #ifdef ENABLE_LE_PERIPHERAL 3814 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3815 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3816 sm_pdu_received_in_wrong_state(sm_conn); 3817 break; 3818 } 3819 3820 // received confirm value 3821 reverse_128(&packet[1], setup->sm_peer_confirm); 3822 3823 #ifdef ENABLE_TESTING_SUPPORT 3824 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3825 log_info("testing_support: reset confirm value"); 3826 memset(setup->sm_peer_confirm, 0, 16); 3827 } 3828 #endif 3829 // notify client to hide shown passkey 3830 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3831 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3832 } 3833 3834 // handle user cancel pairing? 3835 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3836 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3837 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3838 break; 3839 } 3840 3841 // wait for user action? 3842 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3843 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3844 break; 3845 } 3846 3847 // calculate and send local_confirm 3848 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3849 break; 3850 3851 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3852 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3853 sm_pdu_received_in_wrong_state(sm_conn); 3854 break;; 3855 } 3856 3857 // received random value 3858 reverse_128(&packet[1], setup->sm_peer_random); 3859 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3860 break; 3861 #endif 3862 3863 case SM_PH3_RECEIVE_KEYS: 3864 switch(sm_pdu_code){ 3865 case SM_CODE_ENCRYPTION_INFORMATION: 3866 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3867 reverse_128(&packet[1], setup->sm_peer_ltk); 3868 break; 3869 3870 case SM_CODE_MASTER_IDENTIFICATION: 3871 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3872 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3873 reverse_64(&packet[3], setup->sm_peer_rand); 3874 break; 3875 3876 case SM_CODE_IDENTITY_INFORMATION: 3877 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3878 reverse_128(&packet[1], setup->sm_peer_irk); 3879 break; 3880 3881 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3882 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3883 setup->sm_peer_addr_type = packet[1]; 3884 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3885 break; 3886 3887 case SM_CODE_SIGNING_INFORMATION: 3888 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3889 reverse_128(&packet[1], setup->sm_peer_csrk); 3890 break; 3891 default: 3892 // Unexpected PDU 3893 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3894 break; 3895 } 3896 // done with key distribution? 3897 if (sm_key_distribution_all_received(sm_conn)){ 3898 3899 sm_key_distribution_handle_all_received(sm_conn); 3900 3901 if (IS_RESPONDER(sm_conn->sm_role)){ 3902 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3903 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3904 } else { 3905 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3906 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3907 sm_done_for_handle(sm_conn->sm_handle); 3908 } 3909 } else { 3910 if (setup->sm_use_secure_connections){ 3911 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3912 } else { 3913 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3914 } 3915 } 3916 } 3917 break; 3918 default: 3919 // Unexpected PDU 3920 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3921 break; 3922 } 3923 3924 // try to send preparared packet 3925 sm_run(); 3926 } 3927 3928 // Security Manager Client API 3929 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3930 sm_get_oob_data = get_oob_data_callback; 3931 } 3932 3933 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)){ 3934 sm_get_sc_oob_data = get_sc_oob_data_callback; 3935 } 3936 3937 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3938 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3939 } 3940 3941 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3942 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3943 } 3944 3945 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3946 sm_min_encryption_key_size = min_size; 3947 sm_max_encryption_key_size = max_size; 3948 } 3949 3950 void sm_set_authentication_requirements(uint8_t auth_req){ 3951 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3952 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3953 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3954 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3955 } 3956 #endif 3957 sm_auth_req = auth_req; 3958 } 3959 3960 void sm_set_io_capabilities(io_capability_t io_capability){ 3961 sm_io_capabilities = io_capability; 3962 } 3963 3964 #ifdef ENABLE_LE_PERIPHERAL 3965 void sm_set_request_security(int enable){ 3966 sm_slave_request_security = enable; 3967 } 3968 #endif 3969 3970 void sm_set_er(sm_key_t er){ 3971 (void)memcpy(sm_persistent_er, er, 16); 3972 } 3973 3974 void sm_set_ir(sm_key_t ir){ 3975 (void)memcpy(sm_persistent_ir, ir, 16); 3976 } 3977 3978 // Testing support only 3979 void sm_test_set_irk(sm_key_t irk){ 3980 (void)memcpy(sm_persistent_irk, irk, 16); 3981 dkg_state = DKG_CALC_DHK; 3982 test_use_fixed_local_irk = true; 3983 } 3984 3985 void sm_test_use_fixed_local_csrk(void){ 3986 test_use_fixed_local_csrk = true; 3987 } 3988 3989 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3990 static void sm_ec_generated(void * arg){ 3991 UNUSED(arg); 3992 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3993 // trigger pairing if pending for ec key 3994 sm_run(); 3995 } 3996 static void sm_ec_generate_new_key(void){ 3997 log_info("sm: generate new ec key"); 3998 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3999 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4000 } 4001 #endif 4002 4003 #ifdef ENABLE_TESTING_SUPPORT 4004 void sm_test_set_pairing_failure(int reason){ 4005 test_pairing_failure = reason; 4006 } 4007 #endif 4008 4009 void sm_init(void){ 4010 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4011 sm_er_ir_set_default(); 4012 4013 // defaults 4014 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4015 | SM_STK_GENERATION_METHOD_OOB 4016 | SM_STK_GENERATION_METHOD_PASSKEY 4017 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4018 4019 sm_max_encryption_key_size = 16; 4020 sm_min_encryption_key_size = 7; 4021 4022 sm_fixed_passkey_in_display_role = 0xffffffff; 4023 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4024 4025 #ifdef USE_CMAC_ENGINE 4026 sm_cmac_active = 0; 4027 #endif 4028 dkg_state = DKG_W4_WORKING; 4029 rau_state = RAU_IDLE; 4030 sm_aes128_state = SM_AES128_IDLE; 4031 sm_address_resolution_test = -1; // no private address to resolve yet 4032 sm_address_resolution_ah_calculation_active = 0; 4033 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4034 sm_address_resolution_general_queue = NULL; 4035 4036 gap_random_adress_update_period = 15 * 60 * 1000L; 4037 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4038 4039 test_use_fixed_local_csrk = false; 4040 4041 // register for HCI Events from HCI 4042 hci_event_callback_registration.callback = &sm_event_packet_handler; 4043 hci_add_event_handler(&hci_event_callback_registration); 4044 4045 // 4046 btstack_crypto_init(); 4047 4048 // init le_device_db 4049 le_device_db_init(); 4050 4051 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4052 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4053 4054 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4055 sm_ec_generate_new_key(); 4056 #endif 4057 } 4058 4059 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4060 sm_fixed_passkey_in_display_role = passkey; 4061 } 4062 4063 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4064 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4065 } 4066 4067 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4068 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4069 if (!hci_con) return NULL; 4070 return &hci_con->sm_connection; 4071 } 4072 4073 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4074 switch (sm_conn->sm_engine_state){ 4075 case SM_GENERAL_IDLE: 4076 case SM_RESPONDER_IDLE: 4077 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4078 sm_run(); 4079 break; 4080 default: 4081 break; 4082 } 4083 } 4084 4085 /** 4086 * @brief Trigger Security Request 4087 */ 4088 void sm_send_security_request(hci_con_handle_t con_handle){ 4089 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4090 if (!sm_conn) return; 4091 sm_send_security_request_for_connection(sm_conn); 4092 } 4093 4094 // request pairing 4095 void sm_request_pairing(hci_con_handle_t con_handle){ 4096 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4097 if (!sm_conn) return; // wrong connection 4098 4099 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4100 if (IS_RESPONDER(sm_conn->sm_role)){ 4101 sm_send_security_request_for_connection(sm_conn); 4102 } else { 4103 // used as a trigger to start central/master/initiator security procedures 4104 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4105 uint8_t ltk[16]; 4106 bool have_ltk; 4107 switch (sm_conn->sm_irk_lookup_state){ 4108 case IRK_LOOKUP_SUCCEEDED: 4109 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4110 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4111 have_ltk = !sm_is_null_key(ltk); 4112 log_info("have ltk %u", have_ltk); 4113 if (have_ltk){ 4114 sm_conn->sm_pairing_requested = 1; 4115 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4116 break; 4117 } 4118 #endif 4119 /* fall through */ 4120 4121 case IRK_LOOKUP_FAILED: 4122 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4123 break; 4124 default: 4125 log_info("irk lookup pending"); 4126 sm_conn->sm_pairing_requested = 1; 4127 break; 4128 } 4129 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4130 sm_conn->sm_pairing_requested = 1; 4131 } 4132 } 4133 sm_run(); 4134 } 4135 4136 // called by client app on authorization request 4137 void sm_authorization_decline(hci_con_handle_t con_handle){ 4138 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4139 if (!sm_conn) return; // wrong connection 4140 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4141 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4142 } 4143 4144 void sm_authorization_grant(hci_con_handle_t con_handle){ 4145 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4146 if (!sm_conn) return; // wrong connection 4147 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4148 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4149 } 4150 4151 // GAP Bonding API 4152 4153 void sm_bonding_decline(hci_con_handle_t con_handle){ 4154 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4155 if (!sm_conn) return; // wrong connection 4156 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4157 log_info("decline, state %u", sm_conn->sm_engine_state); 4158 switch(sm_conn->sm_engine_state){ 4159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4160 case SM_SC_W4_USER_RESPONSE: 4161 case SM_SC_W4_CONFIRMATION: 4162 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4163 #endif 4164 case SM_PH1_W4_USER_RESPONSE: 4165 switch (setup->sm_stk_generation_method){ 4166 case PK_RESP_INPUT: 4167 case PK_INIT_INPUT: 4168 case PK_BOTH_INPUT: 4169 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4170 break; 4171 case NUMERIC_COMPARISON: 4172 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4173 break; 4174 case JUST_WORKS: 4175 case OOB: 4176 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4177 break; 4178 } 4179 break; 4180 default: 4181 break; 4182 } 4183 sm_run(); 4184 } 4185 4186 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4187 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4188 if (!sm_conn) return; // wrong connection 4189 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4190 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4191 if (setup->sm_use_secure_connections){ 4192 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4193 } else { 4194 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4195 } 4196 } 4197 4198 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4199 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4200 sm_sc_prepare_dhkey_check(sm_conn); 4201 } 4202 #endif 4203 4204 sm_run(); 4205 } 4206 4207 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4208 // for now, it's the same 4209 sm_just_works_confirm(con_handle); 4210 } 4211 4212 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4213 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4214 if (!sm_conn) return; // wrong connection 4215 sm_reset_tk(); 4216 big_endian_store_32(setup->sm_tk, 12, passkey); 4217 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4218 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4219 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4220 } 4221 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4222 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4223 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4224 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4225 sm_sc_start_calculating_local_confirm(sm_conn); 4226 } 4227 #endif 4228 sm_run(); 4229 } 4230 4231 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4232 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4233 if (!sm_conn) return; // wrong connection 4234 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4235 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4236 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4237 switch (action){ 4238 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4239 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4240 flags |= (1 << action); 4241 break; 4242 case SM_KEYPRESS_PASSKEY_CLEARED: 4243 // clear counter, keypress & erased flags + set passkey cleared 4244 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4245 break; 4246 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4247 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4248 // erase actions queued 4249 num_actions--; 4250 if (num_actions == 0){ 4251 // clear counter, keypress & erased flags 4252 flags &= 0x19; 4253 } 4254 break; 4255 } 4256 num_actions++; 4257 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4258 break; 4259 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4260 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4261 // enter actions queued 4262 num_actions--; 4263 if (num_actions == 0){ 4264 // clear counter, keypress & erased flags 4265 flags &= 0x19; 4266 } 4267 break; 4268 } 4269 num_actions++; 4270 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4271 break; 4272 default: 4273 break; 4274 } 4275 setup->sm_keypress_notification = (num_actions << 5) | flags; 4276 sm_run(); 4277 } 4278 4279 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4280 static void sm_handle_random_result_oob(void * arg){ 4281 UNUSED(arg); 4282 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4283 sm_run(); 4284 } 4285 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4286 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4287 sm_sc_oob_callback = callback; 4288 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4289 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4290 return 0; 4291 } 4292 #endif 4293 4294 /** 4295 * @brief Get Identity Resolving state 4296 * @param con_handle 4297 * @return irk_lookup_state_t 4298 */ 4299 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4300 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4301 if (!sm_conn) return IRK_LOOKUP_IDLE; 4302 return sm_conn->sm_irk_lookup_state; 4303 } 4304 4305 /** 4306 * @brief Identify device in LE Device DB 4307 * @param handle 4308 * @returns index from le_device_db or -1 if not found/identified 4309 */ 4310 int sm_le_device_index(hci_con_handle_t con_handle ){ 4311 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4312 if (!sm_conn) return -1; 4313 return sm_conn->sm_le_db_index; 4314 } 4315 4316 static int gap_random_address_type_requires_updates(void){ 4317 switch (gap_random_adress_type){ 4318 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4319 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4320 return 0; 4321 default: 4322 return 1; 4323 } 4324 } 4325 4326 static uint8_t own_address_type(void){ 4327 switch (gap_random_adress_type){ 4328 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4329 return BD_ADDR_TYPE_LE_PUBLIC; 4330 default: 4331 return BD_ADDR_TYPE_LE_RANDOM; 4332 } 4333 } 4334 4335 // GAP LE API 4336 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4337 gap_random_address_update_stop(); 4338 gap_random_adress_type = random_address_type; 4339 hci_le_set_own_address_type(own_address_type()); 4340 if (!gap_random_address_type_requires_updates()) return; 4341 gap_random_address_update_start(); 4342 gap_random_address_trigger(); 4343 } 4344 4345 gap_random_address_type_t gap_random_address_get_mode(void){ 4346 return gap_random_adress_type; 4347 } 4348 4349 void gap_random_address_set_update_period(int period_ms){ 4350 gap_random_adress_update_period = period_ms; 4351 if (!gap_random_address_type_requires_updates()) return; 4352 gap_random_address_update_stop(); 4353 gap_random_address_update_start(); 4354 } 4355 4356 void gap_random_address_set(bd_addr_t addr){ 4357 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4358 (void)memcpy(sm_random_address, addr, 6); 4359 rau_state = RAU_SET_ADDRESS; 4360 sm_run(); 4361 } 4362 4363 #ifdef ENABLE_LE_PERIPHERAL 4364 /* 4365 * @brief Set Advertisement Paramters 4366 * @param adv_int_min 4367 * @param adv_int_max 4368 * @param adv_type 4369 * @param direct_address_type 4370 * @param direct_address 4371 * @param channel_map 4372 * @param filter_policy 4373 * 4374 * @note own_address_type is used from gap_random_address_set_mode 4375 */ 4376 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4377 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4378 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4379 direct_address_typ, direct_address, channel_map, filter_policy); 4380 } 4381 #endif 4382 4383 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4384 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4385 // wrong connection 4386 if (!sm_conn) return 0; 4387 // already encrypted 4388 if (sm_conn->sm_connection_encrypted) return 0; 4389 // only central can re-encrypt 4390 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4391 // irk status? 4392 switch(sm_conn->sm_irk_lookup_state){ 4393 case IRK_LOOKUP_FAILED: 4394 // done, cannot setup encryption 4395 return 0; 4396 case IRK_LOOKUP_SUCCEEDED: 4397 break; 4398 default: 4399 // IR Lookup pending 4400 return 1; 4401 } 4402 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4403 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4404 } 4405