1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_crypto.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "btstack_tlv.h" 53 #include "gap.h" 54 #include "hci.h" 55 #include "hci_dump.h" 56 #include "l2cap.h" 57 58 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 59 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 60 #endif 61 62 // assert SM Public Key can be sent/received 63 #ifdef ENABLE_LE_SECURE_CONNECTIONS 64 #if HCI_ACL_PAYLOAD_SIZE < 69 65 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 66 #endif 67 #endif 68 69 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 70 #define IS_RESPONDER(role) (role) 71 #else 72 #ifdef ENABLE_LE_CENTRAL 73 // only central - never responder (avoid 'unused variable' warnings) 74 #define IS_RESPONDER(role) (0 && role) 75 #else 76 // only peripheral - always responder (avoid 'unused variable' warnings) 77 #define IS_RESPONDER(role) (1 || role) 78 #endif 79 #endif 80 81 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 82 #define USE_CMAC_ENGINE 83 #endif 84 85 #define BTSTACK_TAG32(A,B,C,D) ((A << 24) | (B << 16) | (C << 8) | D) 86 87 // 88 // SM internal types and globals 89 // 90 91 typedef enum { 92 DKG_W4_WORKING, 93 DKG_CALC_IRK, 94 DKG_CALC_DHK, 95 DKG_READY 96 } derived_key_generation_t; 97 98 typedef enum { 99 RAU_IDLE, 100 RAU_GET_RANDOM, 101 RAU_W4_RANDOM, 102 RAU_GET_ENC, 103 RAU_W4_ENC, 104 RAU_SET_ADDRESS, 105 } random_address_update_t; 106 107 typedef enum { 108 CMAC_IDLE, 109 CMAC_CALC_SUBKEYS, 110 CMAC_W4_SUBKEYS, 111 CMAC_CALC_MI, 112 CMAC_W4_MI, 113 CMAC_CALC_MLAST, 114 CMAC_W4_MLAST 115 } cmac_state_t; 116 117 typedef enum { 118 JUST_WORKS, 119 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 120 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 121 PK_BOTH_INPUT, // Only input on both, both input PK 122 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 123 OOB // OOB available on one (SC) or both sides (legacy) 124 } stk_generation_method_t; 125 126 typedef enum { 127 SM_USER_RESPONSE_IDLE, 128 SM_USER_RESPONSE_PENDING, 129 SM_USER_RESPONSE_CONFIRM, 130 SM_USER_RESPONSE_PASSKEY, 131 SM_USER_RESPONSE_DECLINE 132 } sm_user_response_t; 133 134 typedef enum { 135 SM_AES128_IDLE, 136 SM_AES128_ACTIVE 137 } sm_aes128_state_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_IDLE, 141 ADDRESS_RESOLUTION_GENERAL, 142 ADDRESS_RESOLUTION_FOR_CONNECTION, 143 } address_resolution_mode_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_SUCEEDED, 147 ADDRESS_RESOLUTION_FAILED, 148 } address_resolution_event_t; 149 150 typedef enum { 151 EC_KEY_GENERATION_IDLE, 152 EC_KEY_GENERATION_ACTIVE, 153 EC_KEY_GENERATION_DONE, 154 } ec_key_generation_state_t; 155 156 typedef enum { 157 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 158 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 159 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 160 } sm_state_var_t; 161 162 typedef enum { 163 SM_SC_OOB_IDLE, 164 SM_SC_OOB_W4_RANDOM, 165 SM_SC_OOB_W2_CALC_CONFIRM, 166 SM_SC_OOB_W4_CONFIRM, 167 } sm_sc_oob_state_t; 168 169 typedef uint8_t sm_key24_t[3]; 170 typedef uint8_t sm_key56_t[7]; 171 typedef uint8_t sm_key256_t[32]; 172 173 // 174 // GLOBAL DATA 175 // 176 177 static uint8_t test_use_fixed_local_csrk; 178 179 #ifdef ENABLE_TESTING_SUPPORT 180 static uint8_t test_pairing_failure; 181 #endif 182 183 // configuration 184 static uint8_t sm_accepted_stk_generation_methods; 185 static uint8_t sm_max_encryption_key_size; 186 static uint8_t sm_min_encryption_key_size; 187 static uint8_t sm_auth_req = 0; 188 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 189 static uint8_t sm_slave_request_security; 190 static uint32_t sm_fixed_passkey_in_display_role; 191 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 192 193 #ifdef ENABLE_LE_SECURE_CONNECTIONS 194 static uint8_t sm_sc_oob_random[16]; 195 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 196 static sm_sc_oob_state_t sm_sc_oob_state; 197 #endif 198 199 200 static uint8_t sm_persistent_keys_random_active; 201 static const btstack_tlv_t * sm_tlv_impl; 202 static void * sm_tlv_context; 203 204 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 205 static sm_key_t sm_persistent_er; 206 static sm_key_t sm_persistent_ir; 207 208 // derived from sm_persistent_ir 209 static sm_key_t sm_persistent_dhk; 210 static sm_key_t sm_persistent_irk; 211 static derived_key_generation_t dkg_state; 212 213 // derived from sm_persistent_er 214 // .. 215 216 // random address update 217 static random_address_update_t rau_state; 218 static bd_addr_t sm_random_address; 219 220 #ifdef USE_CMAC_ENGINE 221 // CMAC Calculation: General 222 static btstack_crypto_aes128_cmac_t sm_cmac_request; 223 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 224 static uint8_t sm_cmac_active; 225 static uint8_t sm_cmac_hash[16]; 226 #endif 227 228 // CMAC for ATT Signed Writes 229 #ifdef ENABLE_LE_SIGNED_WRITE 230 static uint16_t sm_cmac_signed_write_message_len; 231 static uint8_t sm_cmac_signed_write_header[3]; 232 static const uint8_t * sm_cmac_signed_write_message; 233 static uint8_t sm_cmac_signed_write_sign_counter[4]; 234 #endif 235 236 // CMAC for Secure Connection functions 237 #ifdef ENABLE_LE_SECURE_CONNECTIONS 238 static sm_connection_t * sm_cmac_connection; 239 static uint8_t sm_cmac_sc_buffer[80]; 240 #endif 241 242 // resolvable private address lookup / CSRK calculation 243 static int sm_address_resolution_test; 244 static int sm_address_resolution_ah_calculation_active; 245 static uint8_t sm_address_resolution_addr_type; 246 static bd_addr_t sm_address_resolution_address; 247 static void * sm_address_resolution_context; 248 static address_resolution_mode_t sm_address_resolution_mode; 249 static btstack_linked_list_t sm_address_resolution_general_queue; 250 251 // aes128 crypto engine. 252 static sm_aes128_state_t sm_aes128_state; 253 254 // crypto 255 static btstack_crypto_random_t sm_crypto_random_request; 256 static btstack_crypto_aes128_t sm_crypto_aes128_request; 257 #ifdef ENABLE_LE_SECURE_CONNECTIONS 258 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 259 static btstack_crypto_random_t sm_crypto_random_oob_request; 260 #endif 261 262 // temp storage for random data 263 static uint8_t sm_random_data[8]; 264 static uint8_t sm_aes128_key[16]; 265 static uint8_t sm_aes128_plaintext[16]; 266 static uint8_t sm_aes128_ciphertext[16]; 267 268 // to receive hci events 269 static btstack_packet_callback_registration_t hci_event_callback_registration; 270 271 /* to dispatch sm event */ 272 static btstack_linked_list_t sm_event_handlers; 273 274 // LE Secure Connections 275 #ifdef ENABLE_LE_SECURE_CONNECTIONS 276 static ec_key_generation_state_t ec_key_generation_state; 277 static uint8_t ec_q[64]; 278 #endif 279 280 // 281 // Volume 3, Part H, Chapter 24 282 // "Security shall be initiated by the Security Manager in the device in the master role. 283 // The device in the slave role shall be the responding device." 284 // -> master := initiator, slave := responder 285 // 286 287 // data needed for security setup 288 typedef struct sm_setup_context { 289 290 btstack_timer_source_t sm_timeout; 291 292 // used in all phases 293 uint8_t sm_pairing_failed_reason; 294 295 // user response, (Phase 1 and/or 2) 296 uint8_t sm_user_response; 297 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 298 299 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 300 int sm_key_distribution_send_set; 301 int sm_key_distribution_received_set; 302 303 // Phase 2 (Pairing over SMP) 304 stk_generation_method_t sm_stk_generation_method; 305 sm_key_t sm_tk; 306 uint8_t sm_have_oob_data; 307 uint8_t sm_use_secure_connections; 308 309 sm_key_t sm_c1_t3_value; // c1 calculation 310 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 311 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 312 sm_key_t sm_local_random; 313 sm_key_t sm_local_confirm; 314 sm_key_t sm_peer_random; 315 sm_key_t sm_peer_confirm; 316 uint8_t sm_m_addr_type; // address and type can be removed 317 uint8_t sm_s_addr_type; // '' 318 bd_addr_t sm_m_address; // '' 319 bd_addr_t sm_s_address; // '' 320 sm_key_t sm_ltk; 321 322 uint8_t sm_state_vars; 323 #ifdef ENABLE_LE_SECURE_CONNECTIONS 324 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 325 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 326 sm_key_t sm_local_nonce; // might be combined with sm_local_random 327 sm_key_t sm_dhkey; 328 sm_key_t sm_peer_dhkey_check; 329 sm_key_t sm_local_dhkey_check; 330 sm_key_t sm_ra; 331 sm_key_t sm_rb; 332 sm_key_t sm_t; // used for f5 and h6 333 sm_key_t sm_mackey; 334 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 335 #endif 336 337 // Phase 3 338 339 // key distribution, we generate 340 uint16_t sm_local_y; 341 uint16_t sm_local_div; 342 uint16_t sm_local_ediv; 343 uint8_t sm_local_rand[8]; 344 sm_key_t sm_local_ltk; 345 sm_key_t sm_local_csrk; 346 sm_key_t sm_local_irk; 347 // sm_local_address/addr_type not needed 348 349 // key distribution, received from peer 350 uint16_t sm_peer_y; 351 uint16_t sm_peer_div; 352 uint16_t sm_peer_ediv; 353 uint8_t sm_peer_rand[8]; 354 sm_key_t sm_peer_ltk; 355 sm_key_t sm_peer_irk; 356 sm_key_t sm_peer_csrk; 357 uint8_t sm_peer_addr_type; 358 bd_addr_t sm_peer_address; 359 360 } sm_setup_context_t; 361 362 // 363 static sm_setup_context_t the_setup; 364 static sm_setup_context_t * setup = &the_setup; 365 366 // active connection - the one for which the_setup is used for 367 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 368 369 // @returns 1 if oob data is available 370 // stores oob data in provided 16 byte buffer if not null 371 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 372 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 373 374 // horizontal: initiator capabilities 375 // vertial: responder capabilities 376 static const stk_generation_method_t stk_generation_method [5] [5] = { 377 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 378 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 379 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 380 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 381 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 382 }; 383 384 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 385 #ifdef ENABLE_LE_SECURE_CONNECTIONS 386 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 387 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 388 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 389 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 390 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 391 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 392 }; 393 #endif 394 395 static void sm_run(void); 396 #ifdef USE_CMAC_ENGINE 397 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 398 #endif 399 static void sm_done_for_handle(hci_con_handle_t con_handle); 400 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 401 static inline int sm_calc_actual_encryption_key_size(int other); 402 static int sm_validate_stk_generation_method(void); 403 static void sm_handle_encryption_result_address_resolution(void *arg); 404 static void sm_handle_encryption_result_dkg_dhk(void *arg); 405 static void sm_handle_encryption_result_dkg_irk(void *arg); 406 static void sm_handle_encryption_result_enc_a(void *arg); 407 static void sm_handle_encryption_result_enc_b(void *arg); 408 static void sm_handle_encryption_result_enc_c(void *arg); 409 static void sm_handle_encryption_result_enc_csrk(void *arg); 410 static void sm_handle_encryption_result_enc_d(void * arg); 411 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 412 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 413 #ifdef ENABLE_LE_PERIPHERAL 414 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 415 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 416 #endif 417 static void sm_handle_encryption_result_enc_stk(void *arg); 418 static void sm_handle_encryption_result_rau(void *arg); 419 static void sm_handle_random_result_ph2_tk(void * arg); 420 static void sm_handle_random_result_rau(void * arg); 421 #ifdef ENABLE_LE_SECURE_CONNECTIONS 422 static void sm_ec_generate_new_key(void); 423 static void sm_handle_random_result_sc_get_random(void * arg); 424 static int sm_passkey_entry(stk_generation_method_t method); 425 #endif 426 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 427 428 static void log_info_hex16(const char * name, uint16_t value){ 429 log_info("%-6s 0x%04x", name, value); 430 } 431 432 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 433 // return packet[0]; 434 // } 435 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 436 return packet[1]; 437 } 438 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 439 return packet[2]; 440 } 441 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 442 return packet[3]; 443 } 444 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 445 return packet[4]; 446 } 447 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 448 return packet[5]; 449 } 450 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 451 return packet[6]; 452 } 453 454 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 455 packet[0] = code; 456 } 457 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 458 packet[1] = io_capability; 459 } 460 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 461 packet[2] = oob_data_flag; 462 } 463 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 464 packet[3] = auth_req; 465 } 466 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 467 packet[4] = max_encryption_key_size; 468 } 469 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 470 packet[5] = initiator_key_distribution; 471 } 472 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 473 packet[6] = responder_key_distribution; 474 } 475 476 // @returns 1 if all bytes are 0 477 static int sm_is_null(uint8_t * data, int size){ 478 int i; 479 for (i=0; i < size ; i++){ 480 if (data[i]) return 0; 481 } 482 return 1; 483 } 484 485 static int sm_is_null_random(uint8_t random[8]){ 486 return sm_is_null(random, 8); 487 } 488 489 static int sm_is_null_key(uint8_t * key){ 490 return sm_is_null(key, 16); 491 } 492 493 // Key utils 494 static void sm_reset_tk(void){ 495 int i; 496 for (i=0;i<16;i++){ 497 setup->sm_tk[i] = 0; 498 } 499 } 500 501 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 502 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 503 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 504 int i; 505 for (i = max_encryption_size ; i < 16 ; i++){ 506 key[15-i] = 0; 507 } 508 } 509 510 // ER / IR checks 511 static void sm_er_ir_set_default(void){ 512 int i; 513 for (i=0;i<16;i++){ 514 sm_persistent_er[i] = 0x30 + i; 515 sm_persistent_ir[i] = 0x90 + i; 516 } 517 } 518 519 static int sm_er_is_default(void){ 520 int i; 521 for (i=0;i<16;i++){ 522 if (sm_persistent_er[i] != (0x30+i)) return 0; 523 } 524 return 1; 525 } 526 527 static int sm_ir_is_default(void){ 528 int i; 529 for (i=0;i<16;i++){ 530 if (sm_persistent_ir[i] != (0x90+i)) return 0; 531 } 532 return 1; 533 } 534 535 // SMP Timeout implementation 536 537 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 538 // the Security Manager Timer shall be reset and started. 539 // 540 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 541 // 542 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 543 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 544 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 545 // established. 546 547 static void sm_timeout_handler(btstack_timer_source_t * timer){ 548 log_info("SM timeout"); 549 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 550 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 551 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 552 sm_done_for_handle(sm_conn->sm_handle); 553 554 // trigger handling of next ready connection 555 sm_run(); 556 } 557 static void sm_timeout_start(sm_connection_t * sm_conn){ 558 btstack_run_loop_remove_timer(&setup->sm_timeout); 559 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 560 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 561 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 562 btstack_run_loop_add_timer(&setup->sm_timeout); 563 } 564 static void sm_timeout_stop(void){ 565 btstack_run_loop_remove_timer(&setup->sm_timeout); 566 } 567 static void sm_timeout_reset(sm_connection_t * sm_conn){ 568 sm_timeout_stop(); 569 sm_timeout_start(sm_conn); 570 } 571 572 // end of sm timeout 573 574 // GAP Random Address updates 575 static gap_random_address_type_t gap_random_adress_type; 576 static btstack_timer_source_t gap_random_address_update_timer; 577 static uint32_t gap_random_adress_update_period; 578 579 static void gap_random_address_trigger(void){ 580 log_info("gap_random_address_trigger, state %u", rau_state); 581 if (rau_state != RAU_IDLE) return; 582 rau_state = RAU_GET_RANDOM; 583 sm_run(); 584 } 585 586 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 587 UNUSED(timer); 588 589 log_info("GAP Random Address Update due"); 590 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 591 btstack_run_loop_add_timer(&gap_random_address_update_timer); 592 gap_random_address_trigger(); 593 } 594 595 static void gap_random_address_update_start(void){ 596 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 597 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 598 btstack_run_loop_add_timer(&gap_random_address_update_timer); 599 } 600 601 static void gap_random_address_update_stop(void){ 602 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 603 } 604 605 // ah(k,r) helper 606 // r = padding || r 607 // r - 24 bit value 608 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 609 // r'= padding || r 610 memset(r_prime, 0, 16); 611 memcpy(&r_prime[13], r, 3); 612 } 613 614 // d1 helper 615 // d' = padding || r || d 616 // d,r - 16 bit values 617 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 618 // d'= padding || r || d 619 memset(d1_prime, 0, 16); 620 big_endian_store_16(d1_prime, 12, r); 621 big_endian_store_16(d1_prime, 14, d); 622 } 623 624 // dm helper 625 // r’ = padding || r 626 // r - 64 bit value 627 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 628 memset(r_prime, 0, 16); 629 memcpy(&r_prime[8], r, 8); 630 } 631 632 // calculate arguments for first AES128 operation in C1 function 633 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 634 635 // p1 = pres || preq || rat’ || iat’ 636 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 637 // cant octet of pres becomes the most significant octet of p1. 638 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 639 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 640 // p1 is 0x05000800000302070710000001010001." 641 642 sm_key_t p1; 643 reverse_56(pres, &p1[0]); 644 reverse_56(preq, &p1[7]); 645 p1[14] = rat; 646 p1[15] = iat; 647 log_info_key("p1", p1); 648 log_info_key("r", r); 649 650 // t1 = r xor p1 651 int i; 652 for (i=0;i<16;i++){ 653 t1[i] = r[i] ^ p1[i]; 654 } 655 log_info_key("t1", t1); 656 } 657 658 // calculate arguments for second AES128 operation in C1 function 659 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 660 // p2 = padding || ia || ra 661 // "The least significant octet of ra becomes the least significant octet of p2 and 662 // the most significant octet of padding becomes the most significant octet of p2. 663 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 664 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 665 666 sm_key_t p2; 667 memset(p2, 0, 16); 668 memcpy(&p2[4], ia, 6); 669 memcpy(&p2[10], ra, 6); 670 log_info_key("p2", p2); 671 672 // c1 = e(k, t2_xor_p2) 673 int i; 674 for (i=0;i<16;i++){ 675 t3[i] = t2[i] ^ p2[i]; 676 } 677 log_info_key("t3", t3); 678 } 679 680 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 681 log_info_key("r1", r1); 682 log_info_key("r2", r2); 683 memcpy(&r_prime[8], &r2[8], 8); 684 memcpy(&r_prime[0], &r1[8], 8); 685 } 686 687 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 688 UNUSED(channel); 689 690 // log event 691 hci_dump_packet(packet_type, 1, packet, size); 692 // dispatch to all event handlers 693 btstack_linked_list_iterator_t it; 694 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 695 while (btstack_linked_list_iterator_has_next(&it)){ 696 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 697 entry->callback(packet_type, 0, packet, size); 698 } 699 } 700 701 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 702 event[0] = type; 703 event[1] = event_size - 2; 704 little_endian_store_16(event, 2, con_handle); 705 event[4] = addr_type; 706 reverse_bd_addr(address, &event[5]); 707 } 708 709 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 710 uint8_t event[11]; 711 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 712 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 713 } 714 715 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 716 uint8_t event[15]; 717 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 718 little_endian_store_32(event, 11, passkey); 719 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 720 } 721 722 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 723 // fetch addr and addr type from db 724 bd_addr_t identity_address; 725 int identity_address_type; 726 le_device_db_info(index, &identity_address_type, identity_address, NULL); 727 728 uint8_t event[20]; 729 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 730 event[11] = identity_address_type; 731 reverse_bd_addr(identity_address, &event[12]); 732 little_endian_store_16(event, 18, index); 733 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 734 } 735 736 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 737 uint8_t event[12]; 738 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 739 event[11] = status; 740 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 741 } 742 743 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 744 uint8_t event[13]; 745 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 746 event[11] = status; 747 event[12] = reason; 748 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 749 } 750 751 // decide on stk generation based on 752 // - pairing request 753 // - io capabilities 754 // - OOB data availability 755 static void sm_setup_tk(void){ 756 757 // default: just works 758 setup->sm_stk_generation_method = JUST_WORKS; 759 760 #ifdef ENABLE_LE_SECURE_CONNECTIONS 761 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 762 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 763 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 764 #else 765 setup->sm_use_secure_connections = 0; 766 #endif 767 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 768 769 770 // decide if OOB will be used based on SC vs. Legacy and oob flags 771 int use_oob = 0; 772 if (setup->sm_use_secure_connections){ 773 // In LE Secure Connections pairing, the out of band method is used if at least 774 // one device has the peer device's out of band authentication data available. 775 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 776 } else { 777 // In LE legacy pairing, the out of band method is used if both the devices have 778 // the other device's out of band authentication data available. 779 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 780 } 781 if (use_oob){ 782 log_info("SM: have OOB data"); 783 log_info_key("OOB", setup->sm_tk); 784 setup->sm_stk_generation_method = OOB; 785 return; 786 } 787 788 // If both devices have not set the MITM option in the Authentication Requirements 789 // Flags, then the IO capabilities shall be ignored and the Just Works association 790 // model shall be used. 791 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 792 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 793 log_info("SM: MITM not required by both -> JUST WORKS"); 794 return; 795 } 796 797 // Reset TK as it has been setup in sm_init_setup 798 sm_reset_tk(); 799 800 // Also use just works if unknown io capabilites 801 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 802 return; 803 } 804 805 // Otherwise the IO capabilities of the devices shall be used to determine the 806 // pairing method as defined in Table 2.4. 807 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 808 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 809 810 #ifdef ENABLE_LE_SECURE_CONNECTIONS 811 // table not define by default 812 if (setup->sm_use_secure_connections){ 813 generation_method = stk_generation_method_with_secure_connection; 814 } 815 #endif 816 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 817 818 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 819 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 820 } 821 822 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 823 int flags = 0; 824 if (key_set & SM_KEYDIST_ENC_KEY){ 825 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 826 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 827 } 828 if (key_set & SM_KEYDIST_ID_KEY){ 829 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 830 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 831 } 832 if (key_set & SM_KEYDIST_SIGN){ 833 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 834 } 835 return flags; 836 } 837 838 static void sm_setup_key_distribution(uint8_t key_set){ 839 setup->sm_key_distribution_received_set = 0; 840 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 841 } 842 843 // CSRK Key Lookup 844 845 846 static int sm_address_resolution_idle(void){ 847 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 848 } 849 850 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 851 memcpy(sm_address_resolution_address, addr, 6); 852 sm_address_resolution_addr_type = addr_type; 853 sm_address_resolution_test = 0; 854 sm_address_resolution_mode = mode; 855 sm_address_resolution_context = context; 856 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 857 } 858 859 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 860 // check if already in list 861 btstack_linked_list_iterator_t it; 862 sm_lookup_entry_t * entry; 863 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 864 while(btstack_linked_list_iterator_has_next(&it)){ 865 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 866 if (entry->address_type != address_type) continue; 867 if (memcmp(entry->address, address, 6)) continue; 868 // already in list 869 return BTSTACK_BUSY; 870 } 871 entry = btstack_memory_sm_lookup_entry_get(); 872 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 873 entry->address_type = (bd_addr_type_t) address_type; 874 memcpy(entry->address, address, 6); 875 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 876 sm_run(); 877 return 0; 878 } 879 880 // CMAC calculation using AES Engineq 881 #ifdef USE_CMAC_ENGINE 882 883 static void sm_cmac_done_trampoline(void * arg){ 884 UNUSED(arg); 885 sm_cmac_active = 0; 886 (*sm_cmac_done_callback)(sm_cmac_hash); 887 sm_run(); 888 } 889 890 int sm_cmac_ready(void){ 891 return sm_cmac_active == 0; 892 } 893 894 // generic cmac calculation 895 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 896 sm_cmac_active = 1; 897 sm_cmac_done_callback = done_callback; 898 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 899 } 900 #endif 901 902 // cmac for ATT Message signing 903 #ifdef ENABLE_LE_SIGNED_WRITE 904 905 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 906 sm_cmac_active = 1; 907 sm_cmac_done_callback = done_callback; 908 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 909 } 910 911 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 912 if (offset >= sm_cmac_signed_write_message_len) { 913 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 914 return 0; 915 } 916 917 offset = sm_cmac_signed_write_message_len - 1 - offset; 918 919 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 920 if (offset < 3){ 921 return sm_cmac_signed_write_header[offset]; 922 } 923 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 924 if (offset < actual_message_len_incl_header){ 925 return sm_cmac_signed_write_message[offset - 3]; 926 } 927 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 928 } 929 930 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 931 // ATT Message Signing 932 sm_cmac_signed_write_header[0] = opcode; 933 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 934 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 935 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 936 sm_cmac_signed_write_message = message; 937 sm_cmac_signed_write_message_len = total_message_len; 938 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 939 } 940 #endif 941 942 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 943 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 944 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 945 switch (setup->sm_stk_generation_method){ 946 case PK_RESP_INPUT: 947 if (IS_RESPONDER(sm_conn->sm_role)){ 948 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 949 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 950 } else { 951 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 952 } 953 break; 954 case PK_INIT_INPUT: 955 if (IS_RESPONDER(sm_conn->sm_role)){ 956 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 957 } else { 958 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 959 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 960 } 961 break; 962 case PK_BOTH_INPUT: 963 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 964 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 965 break; 966 case NUMERIC_COMPARISON: 967 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 968 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 969 break; 970 case JUST_WORKS: 971 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 972 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 973 break; 974 case OOB: 975 // client already provided OOB data, let's skip notification. 976 break; 977 } 978 } 979 980 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 981 int recv_flags; 982 if (IS_RESPONDER(sm_conn->sm_role)){ 983 // slave / responder 984 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 985 } else { 986 // master / initiator 987 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 988 } 989 990 #ifdef ENABLE_LE_SECURE_CONNECTIONS 991 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 992 if (setup->sm_use_secure_connections){ 993 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 994 } 995 #endif 996 997 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 998 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 999 } 1000 1001 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1002 if (sm_active_connection_handle == con_handle){ 1003 sm_timeout_stop(); 1004 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1005 log_info("sm: connection 0x%x released setup context", con_handle); 1006 1007 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1008 // generate new ec key after each pairing (that used it) 1009 if (setup->sm_use_secure_connections){ 1010 sm_ec_generate_new_key(); 1011 } 1012 #endif 1013 } 1014 } 1015 1016 static int sm_key_distribution_flags_for_auth_req(void){ 1017 1018 int flags = SM_KEYDIST_ID_KEY; 1019 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1020 // encryption and signing information only if bonding requested 1021 flags |= SM_KEYDIST_ENC_KEY; 1022 #ifdef ENABLE_LE_SIGNED_WRITE 1023 flags |= SM_KEYDIST_SIGN; 1024 #endif 1025 } 1026 return flags; 1027 } 1028 1029 static void sm_reset_setup(void){ 1030 // fill in sm setup 1031 setup->sm_state_vars = 0; 1032 setup->sm_keypress_notification = 0; 1033 sm_reset_tk(); 1034 } 1035 1036 static void sm_init_setup(sm_connection_t * sm_conn){ 1037 1038 // fill in sm setup 1039 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1040 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1041 1042 // query client for Legacy Pairing OOB data 1043 setup->sm_have_oob_data = 0; 1044 if (sm_get_oob_data) { 1045 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1046 } 1047 1048 // if available and SC supported, also ask for SC OOB Data 1049 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1050 memset(setup->sm_ra, 0, 16); 1051 memset(setup->sm_rb, 0, 16); 1052 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1053 if (sm_get_sc_oob_data){ 1054 if (IS_RESPONDER(sm_conn->sm_role)){ 1055 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1056 sm_conn->sm_peer_addr_type, 1057 sm_conn->sm_peer_address, 1058 setup->sm_peer_confirm, 1059 setup->sm_ra); 1060 } else { 1061 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1062 sm_conn->sm_peer_addr_type, 1063 sm_conn->sm_peer_address, 1064 setup->sm_peer_confirm, 1065 setup->sm_rb); 1066 } 1067 } else { 1068 setup->sm_have_oob_data = 0; 1069 } 1070 } 1071 #endif 1072 1073 sm_pairing_packet_t * local_packet; 1074 if (IS_RESPONDER(sm_conn->sm_role)){ 1075 // slave 1076 local_packet = &setup->sm_s_pres; 1077 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1078 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1079 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1080 } else { 1081 // master 1082 local_packet = &setup->sm_m_preq; 1083 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1084 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1085 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1086 1087 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1088 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1089 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1090 } 1091 1092 uint8_t auth_req = sm_auth_req; 1093 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1094 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1095 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1096 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1097 } 1098 1099 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1100 1101 sm_pairing_packet_t * remote_packet; 1102 int remote_key_request; 1103 if (IS_RESPONDER(sm_conn->sm_role)){ 1104 // slave / responder 1105 remote_packet = &setup->sm_m_preq; 1106 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1107 } else { 1108 // master / initiator 1109 remote_packet = &setup->sm_s_pres; 1110 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1111 } 1112 1113 // check key size 1114 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1115 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1116 1117 // decide on STK generation method / SC 1118 sm_setup_tk(); 1119 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1120 1121 // check if STK generation method is acceptable by client 1122 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1123 1124 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1125 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1126 if (setup->sm_use_secure_connections){ 1127 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1128 } 1129 #endif 1130 1131 // identical to responder 1132 sm_setup_key_distribution(remote_key_request); 1133 1134 // JUST WORKS doens't provide authentication 1135 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1136 1137 return 0; 1138 } 1139 1140 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1141 1142 // cache and reset context 1143 int matched_device_id = sm_address_resolution_test; 1144 address_resolution_mode_t mode = sm_address_resolution_mode; 1145 void * context = sm_address_resolution_context; 1146 1147 // reset context 1148 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1149 sm_address_resolution_context = NULL; 1150 sm_address_resolution_test = -1; 1151 hci_con_handle_t con_handle = 0; 1152 1153 sm_connection_t * sm_connection; 1154 #ifdef ENABLE_LE_CENTRAL 1155 sm_key_t ltk; 1156 int have_ltk; 1157 int pairing_need; 1158 #endif 1159 switch (mode){ 1160 case ADDRESS_RESOLUTION_GENERAL: 1161 break; 1162 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1163 sm_connection = (sm_connection_t *) context; 1164 con_handle = sm_connection->sm_handle; 1165 switch (event){ 1166 case ADDRESS_RESOLUTION_SUCEEDED: 1167 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1168 sm_connection->sm_le_db_index = matched_device_id; 1169 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1170 if (sm_connection->sm_role) { 1171 // LTK request received before, IRK required -> start LTK calculation 1172 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1173 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1174 } 1175 break; 1176 } 1177 #ifdef ENABLE_LE_CENTRAL 1178 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1179 have_ltk = !sm_is_null_key(ltk); 1180 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1181 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1182 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1183 // reset requests 1184 sm_connection->sm_security_request_received = 0; 1185 sm_connection->sm_pairing_requested = 0; 1186 1187 // have ltk -> start encryption 1188 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1189 // "When a bond has been created between two devices, any reconnection should result in the local device 1190 // enabling or requesting encryption with the remote device before initiating any service request." 1191 if (have_ltk){ 1192 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1193 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1194 break; 1195 #else 1196 log_info("central: defer enabling encryption for bonded device"); 1197 #endif 1198 } 1199 // pairint_request -> send pairing request 1200 if (pairing_need){ 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1202 break; 1203 } 1204 #endif 1205 break; 1206 case ADDRESS_RESOLUTION_FAILED: 1207 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1208 if (sm_connection->sm_role) { 1209 // LTK request received before, IRK required -> negative LTK reply 1210 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1211 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1212 } 1213 break; 1214 } 1215 #ifdef ENABLE_LE_CENTRAL 1216 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1217 sm_connection->sm_security_request_received = 0; 1218 sm_connection->sm_pairing_requested = 0; 1219 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1220 #endif 1221 break; 1222 } 1223 break; 1224 default: 1225 break; 1226 } 1227 1228 switch (event){ 1229 case ADDRESS_RESOLUTION_SUCEEDED: 1230 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1231 break; 1232 case ADDRESS_RESOLUTION_FAILED: 1233 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1234 break; 1235 } 1236 } 1237 1238 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1239 1240 int le_db_index = -1; 1241 1242 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1243 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1244 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1245 & SM_AUTHREQ_BONDING ) != 0; 1246 1247 if (bonding_enabed){ 1248 1249 // lookup device based on IRK 1250 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1251 int i; 1252 for (i=0; i < le_device_db_max_count(); i++){ 1253 sm_key_t irk; 1254 bd_addr_t address; 1255 int address_type = BD_ADDR_TYPE_UNKNOWN; 1256 le_device_db_info(i, &address_type, address, irk); 1257 // check if valid entry retrieved 1258 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1259 // compare IRK 1260 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1261 1262 log_info("sm: device found for IRK, updating"); 1263 le_db_index = i; 1264 break; 1265 } 1266 } else { 1267 // assert IRK is set to zero 1268 memset(setup->sm_peer_irk, 0, 16); 1269 } 1270 1271 // if not found, lookup via public address if possible 1272 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1273 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1274 int i; 1275 for (i=0; i < le_device_db_max_count(); i++){ 1276 bd_addr_t address; 1277 int address_type; 1278 le_device_db_info(i, &address_type, address, NULL); 1279 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1280 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1281 log_info("sm: device found for public address, updating"); 1282 le_db_index = i; 1283 break; 1284 } 1285 } 1286 } 1287 1288 // if not found, add to db 1289 if (le_db_index < 0) { 1290 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1291 } 1292 1293 if (le_db_index >= 0){ 1294 1295 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1296 1297 #ifdef ENABLE_LE_SIGNED_WRITE 1298 // store local CSRK 1299 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1300 log_info("sm: store local CSRK"); 1301 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1302 le_device_db_local_counter_set(le_db_index, 0); 1303 } 1304 1305 // store remote CSRK 1306 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1307 log_info("sm: store remote CSRK"); 1308 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1309 le_device_db_remote_counter_set(le_db_index, 0); 1310 } 1311 #endif 1312 // store encryption information for secure connections: LTK generated by ECDH 1313 if (setup->sm_use_secure_connections){ 1314 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1315 uint8_t zero_rand[8]; 1316 memset(zero_rand, 0, 8); 1317 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1318 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1319 } 1320 1321 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1322 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1323 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1324 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1325 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1326 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1327 1328 } 1329 } 1330 } else { 1331 log_info("Ignoring received keys, bonding not enabled"); 1332 } 1333 1334 // keep le_db_index 1335 sm_conn->sm_le_db_index = le_db_index; 1336 } 1337 1338 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1339 setup->sm_pairing_failed_reason = reason; 1340 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1341 } 1342 1343 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1344 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1345 } 1346 1347 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1348 1349 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1350 static int sm_passkey_used(stk_generation_method_t method); 1351 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1352 1353 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1354 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1355 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1356 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1357 } else { 1358 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1359 } 1360 } 1361 1362 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1363 if (IS_RESPONDER(sm_conn->sm_role)){ 1364 // Responder 1365 if (setup->sm_stk_generation_method == OOB){ 1366 // generate Nb 1367 log_info("Generate Nb"); 1368 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1369 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1370 } else { 1371 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1372 } 1373 } else { 1374 // Initiator role 1375 switch (setup->sm_stk_generation_method){ 1376 case JUST_WORKS: 1377 sm_sc_prepare_dhkey_check(sm_conn); 1378 break; 1379 1380 case NUMERIC_COMPARISON: 1381 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1382 break; 1383 case PK_INIT_INPUT: 1384 case PK_RESP_INPUT: 1385 case PK_BOTH_INPUT: 1386 if (setup->sm_passkey_bit < 20) { 1387 sm_sc_start_calculating_local_confirm(sm_conn); 1388 } else { 1389 sm_sc_prepare_dhkey_check(sm_conn); 1390 } 1391 break; 1392 case OOB: 1393 sm_sc_prepare_dhkey_check(sm_conn); 1394 break; 1395 } 1396 } 1397 } 1398 1399 static void sm_sc_cmac_done(uint8_t * hash){ 1400 log_info("sm_sc_cmac_done: "); 1401 log_info_hexdump(hash, 16); 1402 1403 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1404 sm_sc_oob_state = SM_SC_OOB_IDLE; 1405 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1406 return; 1407 } 1408 1409 sm_connection_t * sm_conn = sm_cmac_connection; 1410 sm_cmac_connection = NULL; 1411 #ifdef ENABLE_CLASSIC 1412 link_key_type_t link_key_type; 1413 #endif 1414 1415 switch (sm_conn->sm_engine_state){ 1416 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1417 memcpy(setup->sm_local_confirm, hash, 16); 1418 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1419 break; 1420 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1421 // check 1422 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1423 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1424 break; 1425 } 1426 sm_sc_state_after_receiving_random(sm_conn); 1427 break; 1428 case SM_SC_W4_CALCULATE_G2: { 1429 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1430 big_endian_store_32(setup->sm_tk, 12, vab); 1431 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1432 sm_trigger_user_response(sm_conn); 1433 break; 1434 } 1435 case SM_SC_W4_CALCULATE_F5_SALT: 1436 memcpy(setup->sm_t, hash, 16); 1437 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1438 break; 1439 case SM_SC_W4_CALCULATE_F5_MACKEY: 1440 memcpy(setup->sm_mackey, hash, 16); 1441 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1442 break; 1443 case SM_SC_W4_CALCULATE_F5_LTK: 1444 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1445 // Errata Service Release to the Bluetooth Specification: ESR09 1446 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1447 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1448 memcpy(setup->sm_ltk, hash, 16); 1449 memcpy(setup->sm_local_ltk, hash, 16); 1450 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1451 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1452 break; 1453 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1454 memcpy(setup->sm_local_dhkey_check, hash, 16); 1455 if (IS_RESPONDER(sm_conn->sm_role)){ 1456 // responder 1457 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1458 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1459 } else { 1460 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1461 } 1462 } else { 1463 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1464 } 1465 break; 1466 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1467 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1468 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1469 break; 1470 } 1471 if (IS_RESPONDER(sm_conn->sm_role)){ 1472 // responder 1473 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1474 } else { 1475 // initiator 1476 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1477 } 1478 break; 1479 case SM_SC_W4_CALCULATE_H6_ILK: 1480 memcpy(setup->sm_t, hash, 16); 1481 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1482 break; 1483 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1484 #ifdef ENABLE_CLASSIC 1485 reverse_128(hash, setup->sm_t); 1486 link_key_type = sm_conn->sm_connection_authenticated ? 1487 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1488 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1489 if (IS_RESPONDER(sm_conn->sm_role)){ 1490 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1491 } else { 1492 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1493 } 1494 #endif 1495 if (IS_RESPONDER(sm_conn->sm_role)){ 1496 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1497 } else { 1498 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1499 } 1500 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1501 sm_done_for_handle(sm_conn->sm_handle); 1502 break; 1503 default: 1504 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1505 break; 1506 } 1507 sm_run(); 1508 } 1509 1510 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){ 1511 const uint16_t message_len = 65; 1512 sm_cmac_connection = sm_conn; 1513 memcpy(sm_cmac_sc_buffer, u, 32); 1514 memcpy(sm_cmac_sc_buffer+32, v, 32); 1515 sm_cmac_sc_buffer[64] = z; 1516 log_info("f4 key"); 1517 log_info_hexdump(x, 16); 1518 log_info("f4 message"); 1519 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1520 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1521 } 1522 1523 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1524 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1525 static const uint8_t f5_length[] = { 0x01, 0x00}; 1526 1527 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1528 log_info("f5_calculate_salt"); 1529 // calculate salt for f5 1530 const uint16_t message_len = 32; 1531 sm_cmac_connection = sm_conn; 1532 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1533 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1534 } 1535 1536 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){ 1537 const uint16_t message_len = 53; 1538 sm_cmac_connection = sm_conn; 1539 1540 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1541 sm_cmac_sc_buffer[0] = 0; 1542 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1543 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1544 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1545 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1546 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1547 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1548 log_info("f5 key"); 1549 log_info_hexdump(t, 16); 1550 log_info("f5 message for MacKey"); 1551 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1552 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1553 } 1554 1555 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1556 sm_key56_t bd_addr_master, bd_addr_slave; 1557 bd_addr_master[0] = setup->sm_m_addr_type; 1558 bd_addr_slave[0] = setup->sm_s_addr_type; 1559 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1560 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1561 if (IS_RESPONDER(sm_conn->sm_role)){ 1562 // responder 1563 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1564 } else { 1565 // initiator 1566 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1567 } 1568 } 1569 1570 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1571 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1572 const uint16_t message_len = 53; 1573 sm_cmac_connection = sm_conn; 1574 sm_cmac_sc_buffer[0] = 1; 1575 // 1..52 setup before 1576 log_info("f5 key"); 1577 log_info_hexdump(t, 16); 1578 log_info("f5 message for LTK"); 1579 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1580 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1581 } 1582 1583 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1584 f5_ltk(sm_conn, setup->sm_t); 1585 } 1586 1587 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){ 1588 const uint16_t message_len = 65; 1589 sm_cmac_connection = sm_conn; 1590 memcpy(sm_cmac_sc_buffer, n1, 16); 1591 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1592 memcpy(sm_cmac_sc_buffer+32, r, 16); 1593 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1594 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1595 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1596 log_info("f6 key"); 1597 log_info_hexdump(w, 16); 1598 log_info("f6 message"); 1599 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1600 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1601 } 1602 1603 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1604 // - U is 256 bits 1605 // - V is 256 bits 1606 // - X is 128 bits 1607 // - Y is 128 bits 1608 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){ 1609 const uint16_t message_len = 80; 1610 sm_cmac_connection = sm_conn; 1611 memcpy(sm_cmac_sc_buffer, u, 32); 1612 memcpy(sm_cmac_sc_buffer+32, v, 32); 1613 memcpy(sm_cmac_sc_buffer+64, y, 16); 1614 log_info("g2 key"); 1615 log_info_hexdump(x, 16); 1616 log_info("g2 message"); 1617 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1618 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1619 } 1620 1621 static void g2_calculate(sm_connection_t * sm_conn) { 1622 // calc Va if numeric comparison 1623 if (IS_RESPONDER(sm_conn->sm_role)){ 1624 // responder 1625 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1626 } else { 1627 // initiator 1628 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1629 } 1630 } 1631 1632 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1633 uint8_t z = 0; 1634 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1635 // some form of passkey 1636 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1637 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1638 setup->sm_passkey_bit++; 1639 } 1640 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1641 } 1642 1643 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1644 // OOB 1645 if (setup->sm_stk_generation_method == OOB){ 1646 if (IS_RESPONDER(sm_conn->sm_role)){ 1647 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1648 } else { 1649 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1650 } 1651 return; 1652 } 1653 1654 uint8_t z = 0; 1655 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1656 // some form of passkey 1657 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1658 // sm_passkey_bit was increased before sending confirm value 1659 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1660 } 1661 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1662 } 1663 1664 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1665 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1666 1667 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1668 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1669 return; 1670 } else { 1671 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1672 } 1673 } 1674 1675 static void sm_sc_dhkey_calculated(void * arg){ 1676 sm_connection_t * sm_conn = (sm_connection_t *) arg; 1677 log_info("dhkey"); 1678 log_info_hexdump(&setup->sm_dhkey[0], 32); 1679 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1680 // trigger next step 1681 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1682 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1683 } 1684 sm_run(); 1685 } 1686 1687 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1688 // calculate DHKCheck 1689 sm_key56_t bd_addr_master, bd_addr_slave; 1690 bd_addr_master[0] = setup->sm_m_addr_type; 1691 bd_addr_slave[0] = setup->sm_s_addr_type; 1692 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1693 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1694 uint8_t iocap_a[3]; 1695 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1696 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1697 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1698 uint8_t iocap_b[3]; 1699 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1700 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1701 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1702 if (IS_RESPONDER(sm_conn->sm_role)){ 1703 // responder 1704 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); 1705 } else { 1706 // initiator 1707 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); 1708 } 1709 } 1710 1711 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1712 // validate E = f6() 1713 sm_key56_t bd_addr_master, bd_addr_slave; 1714 bd_addr_master[0] = setup->sm_m_addr_type; 1715 bd_addr_slave[0] = setup->sm_s_addr_type; 1716 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1717 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1718 1719 uint8_t iocap_a[3]; 1720 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1721 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1722 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1723 uint8_t iocap_b[3]; 1724 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1725 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1726 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1727 if (IS_RESPONDER(sm_conn->sm_role)){ 1728 // responder 1729 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); 1730 } else { 1731 // initiator 1732 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); 1733 } 1734 } 1735 1736 1737 // 1738 // Link Key Conversion Function h6 1739 // 1740 // h6(W, keyID) = AES-CMACW(keyID) 1741 // - W is 128 bits 1742 // - keyID is 32 bits 1743 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1744 const uint16_t message_len = 4; 1745 sm_cmac_connection = sm_conn; 1746 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1747 log_info("h6 key"); 1748 log_info_hexdump(w, 16); 1749 log_info("h6 message"); 1750 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1751 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1752 } 1753 1754 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1755 // Errata Service Release to the Bluetooth Specification: ESR09 1756 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1757 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1758 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1759 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1760 } 1761 1762 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1763 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1764 } 1765 1766 #endif 1767 1768 // key management legacy connections: 1769 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1770 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1771 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1772 // - responder reconnects: responder uses LTK receveived from master 1773 1774 // key management secure connections: 1775 // - both devices store same LTK from ECDH key exchange. 1776 1777 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1778 static void sm_load_security_info(sm_connection_t * sm_connection){ 1779 int encryption_key_size; 1780 int authenticated; 1781 int authorized; 1782 1783 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1784 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1785 &encryption_key_size, &authenticated, &authorized); 1786 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1787 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1788 sm_connection->sm_connection_authenticated = authenticated; 1789 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1790 } 1791 #endif 1792 1793 #ifdef ENABLE_LE_PERIPHERAL 1794 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1795 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1796 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1797 // re-establish used key encryption size 1798 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1799 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1800 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1801 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1802 log_info("sm: received ltk request with key size %u, authenticated %u", 1803 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1804 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1805 sm_run(); 1806 } 1807 #endif 1808 1809 static void sm_run(void){ 1810 1811 btstack_linked_list_iterator_t it; 1812 1813 // assert that stack has already bootet 1814 if (hci_get_state() != HCI_STATE_WORKING) return; 1815 1816 // assert that we can send at least commands 1817 if (!hci_can_send_command_packet_now()) return; 1818 1819 // pause until IR/ER are ready 1820 if (sm_persistent_keys_random_active) return; 1821 1822 // 1823 // non-connection related behaviour 1824 // 1825 1826 // distributed key generation 1827 switch (dkg_state){ 1828 case DKG_CALC_IRK: 1829 // already busy? 1830 if (sm_aes128_state == SM_AES128_IDLE) { 1831 log_info("DKG_CALC_IRK started"); 1832 // IRK = d1(IR, 1, 0) 1833 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1834 sm_aes128_state = SM_AES128_ACTIVE; 1835 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1836 return; 1837 } 1838 break; 1839 case DKG_CALC_DHK: 1840 // already busy? 1841 if (sm_aes128_state == SM_AES128_IDLE) { 1842 log_info("DKG_CALC_DHK started"); 1843 // DHK = d1(IR, 3, 0) 1844 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1845 sm_aes128_state = SM_AES128_ACTIVE; 1846 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1847 return; 1848 } 1849 break; 1850 default: 1851 break; 1852 } 1853 1854 // random address updates 1855 switch (rau_state){ 1856 case RAU_GET_RANDOM: 1857 rau_state = RAU_W4_RANDOM; 1858 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1859 return; 1860 case RAU_GET_ENC: 1861 // already busy? 1862 if (sm_aes128_state == SM_AES128_IDLE) { 1863 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1864 sm_aes128_state = SM_AES128_ACTIVE; 1865 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1866 return; 1867 } 1868 break; 1869 case RAU_SET_ADDRESS: 1870 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1871 rau_state = RAU_IDLE; 1872 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1873 return; 1874 default: 1875 break; 1876 } 1877 1878 // CSRK Lookup 1879 // -- if csrk lookup ready, find connection that require csrk lookup 1880 if (sm_address_resolution_idle()){ 1881 hci_connections_get_iterator(&it); 1882 while(btstack_linked_list_iterator_has_next(&it)){ 1883 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1884 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1885 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1886 // and start lookup 1887 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); 1888 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1889 break; 1890 } 1891 } 1892 } 1893 1894 // -- if csrk lookup ready, resolved addresses for received addresses 1895 if (sm_address_resolution_idle()) { 1896 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1897 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1898 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1899 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1900 btstack_memory_sm_lookup_entry_free(entry); 1901 } 1902 } 1903 1904 // -- Continue with CSRK device lookup by public or resolvable private address 1905 if (!sm_address_resolution_idle()){ 1906 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1907 while (sm_address_resolution_test < le_device_db_max_count()){ 1908 int addr_type; 1909 bd_addr_t addr; 1910 sm_key_t irk; 1911 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1912 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1913 1914 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1915 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1916 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1917 break; 1918 } 1919 1920 if (sm_address_resolution_addr_type == 0){ 1921 sm_address_resolution_test++; 1922 continue; 1923 } 1924 1925 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1926 1927 log_info("LE Device Lookup: calculate AH"); 1928 log_info_key("IRK", irk); 1929 1930 memcpy(sm_aes128_key, irk, 16); 1931 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1932 sm_address_resolution_ah_calculation_active = 1; 1933 sm_aes128_state = SM_AES128_ACTIVE; 1934 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1935 return; 1936 } 1937 1938 if (sm_address_resolution_test >= le_device_db_max_count()){ 1939 log_info("LE Device Lookup: not found"); 1940 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1941 } 1942 } 1943 1944 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1945 switch (sm_sc_oob_state){ 1946 case SM_SC_OOB_W2_CALC_CONFIRM: 1947 if (!sm_cmac_ready()) break; 1948 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1949 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1950 return; 1951 default: 1952 break; 1953 } 1954 #endif 1955 1956 // assert that we can send at least commands - cmd might have been sent by crypto engine 1957 if (!hci_can_send_command_packet_now()) return; 1958 1959 // handle basic actions that don't requires the full context 1960 hci_connections_get_iterator(&it); 1961 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1962 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1963 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1964 switch(sm_connection->sm_engine_state){ 1965 // responder side 1966 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1967 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1968 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1969 return; 1970 1971 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1972 case SM_SC_RECEIVED_LTK_REQUEST: 1973 switch (sm_connection->sm_irk_lookup_state){ 1974 case IRK_LOOKUP_FAILED: 1975 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1976 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1977 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1978 return; 1979 default: 1980 break; 1981 } 1982 break; 1983 #endif 1984 default: 1985 break; 1986 } 1987 } 1988 1989 // 1990 // active connection handling 1991 // -- use loop to handle next connection if lock on setup context is released 1992 1993 while (1) { 1994 1995 // Find connections that requires setup context and make active if no other is locked 1996 hci_connections_get_iterator(&it); 1997 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1998 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1999 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2000 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2001 int done = 1; 2002 int err; 2003 UNUSED(err); 2004 2005 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2006 // assert ec key is ready 2007 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2008 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2009 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2010 sm_ec_generate_new_key(); 2011 } 2012 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2013 continue; 2014 } 2015 } 2016 #endif 2017 2018 switch (sm_connection->sm_engine_state) { 2019 #ifdef ENABLE_LE_PERIPHERAL 2020 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2021 // send packet if possible, 2022 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2023 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2024 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2025 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2026 } else { 2027 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2028 } 2029 // don't lock sxetup context yet 2030 done = 0; 2031 break; 2032 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2033 sm_reset_setup(); 2034 sm_init_setup(sm_connection); 2035 // recover pairing request 2036 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2037 err = sm_stk_generation_init(sm_connection); 2038 2039 #ifdef ENABLE_TESTING_SUPPORT 2040 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2041 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2042 err = test_pairing_failure; 2043 } 2044 #endif 2045 if (err){ 2046 setup->sm_pairing_failed_reason = err; 2047 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2048 break; 2049 } 2050 sm_timeout_start(sm_connection); 2051 // generate random number first, if we need to show passkey 2052 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2053 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2054 break; 2055 } 2056 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2057 break; 2058 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2059 sm_reset_setup(); 2060 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2061 break; 2062 2063 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2064 case SM_SC_RECEIVED_LTK_REQUEST: 2065 switch (sm_connection->sm_irk_lookup_state){ 2066 case IRK_LOOKUP_SUCCEEDED: 2067 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2068 // start using context by loading security info 2069 sm_reset_setup(); 2070 sm_load_security_info(sm_connection); 2071 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2072 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2073 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2074 break; 2075 } 2076 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2077 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2078 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2079 // don't lock setup context yet 2080 return; 2081 default: 2082 // just wait until IRK lookup is completed 2083 // don't lock setup context yet 2084 done = 0; 2085 break; 2086 } 2087 break; 2088 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2089 #endif /* ENABLE_LE_PERIPHERAL */ 2090 2091 #ifdef ENABLE_LE_CENTRAL 2092 case SM_INITIATOR_PH0_HAS_LTK: 2093 sm_reset_setup(); 2094 sm_load_security_info(sm_connection); 2095 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2096 break; 2097 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2098 sm_reset_setup(); 2099 sm_init_setup(sm_connection); 2100 sm_timeout_start(sm_connection); 2101 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2102 break; 2103 #endif 2104 2105 default: 2106 done = 0; 2107 break; 2108 } 2109 if (done){ 2110 sm_active_connection_handle = sm_connection->sm_handle; 2111 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); 2112 } 2113 } 2114 2115 // 2116 // active connection handling 2117 // 2118 2119 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2120 2121 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2122 if (!connection) { 2123 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2124 return; 2125 } 2126 2127 // assert that we could send a SM PDU - not needed for all of the following 2128 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2129 log_info("cannot send now, requesting can send now event"); 2130 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2131 return; 2132 } 2133 2134 // send keypress notifications 2135 if (setup->sm_keypress_notification){ 2136 int i; 2137 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2138 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2139 uint8_t action = 0; 2140 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2141 if (flags & (1<<i)){ 2142 int clear_flag = 1; 2143 switch (i){ 2144 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2145 case SM_KEYPRESS_PASSKEY_CLEARED: 2146 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2147 default: 2148 break; 2149 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2150 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2151 num_actions--; 2152 clear_flag = num_actions == 0; 2153 break; 2154 } 2155 if (clear_flag){ 2156 flags &= ~(1<<i); 2157 } 2158 action = i; 2159 break; 2160 } 2161 } 2162 setup->sm_keypress_notification = (num_actions << 5) | flags; 2163 2164 // send keypress notification 2165 uint8_t buffer[2]; 2166 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2167 buffer[1] = action; 2168 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2169 2170 // try 2171 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2172 return; 2173 } 2174 2175 int key_distribution_flags; 2176 UNUSED(key_distribution_flags); 2177 2178 log_info("sm_run: state %u", connection->sm_engine_state); 2179 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2180 log_info("sm_run // cannot send"); 2181 } 2182 switch (connection->sm_engine_state){ 2183 2184 // general 2185 case SM_GENERAL_SEND_PAIRING_FAILED: { 2186 uint8_t buffer[2]; 2187 buffer[0] = SM_CODE_PAIRING_FAILED; 2188 buffer[1] = setup->sm_pairing_failed_reason; 2189 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2190 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2191 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2192 sm_done_for_handle(connection->sm_handle); 2193 break; 2194 } 2195 2196 // responding state 2197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2198 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2199 if (!sm_cmac_ready()) break; 2200 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2201 sm_sc_calculate_local_confirm(connection); 2202 break; 2203 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2204 if (!sm_cmac_ready()) break; 2205 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2206 sm_sc_calculate_remote_confirm(connection); 2207 break; 2208 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2209 if (!sm_cmac_ready()) break; 2210 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2211 sm_sc_calculate_f6_for_dhkey_check(connection); 2212 break; 2213 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2214 if (!sm_cmac_ready()) break; 2215 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2216 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2217 break; 2218 case SM_SC_W2_CALCULATE_F5_SALT: 2219 if (!sm_cmac_ready()) break; 2220 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2221 f5_calculate_salt(connection); 2222 break; 2223 case SM_SC_W2_CALCULATE_F5_MACKEY: 2224 if (!sm_cmac_ready()) break; 2225 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2226 f5_calculate_mackey(connection); 2227 break; 2228 case SM_SC_W2_CALCULATE_F5_LTK: 2229 if (!sm_cmac_ready()) break; 2230 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2231 f5_calculate_ltk(connection); 2232 break; 2233 case SM_SC_W2_CALCULATE_G2: 2234 if (!sm_cmac_ready()) break; 2235 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2236 g2_calculate(connection); 2237 break; 2238 case SM_SC_W2_CALCULATE_H6_ILK: 2239 if (!sm_cmac_ready()) break; 2240 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2241 h6_calculate_ilk(connection); 2242 break; 2243 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2244 if (!sm_cmac_ready()) break; 2245 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2246 h6_calculate_br_edr_link_key(connection); 2247 break; 2248 #endif 2249 2250 #ifdef ENABLE_LE_CENTRAL 2251 // initiator side 2252 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2253 sm_key_t peer_ltk_flipped; 2254 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2255 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2256 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2257 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2258 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2259 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2260 return; 2261 } 2262 2263 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2264 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2265 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2266 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2267 sm_timeout_reset(connection); 2268 break; 2269 #endif 2270 2271 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2272 2273 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2274 int trigger_user_response = 0; 2275 2276 uint8_t buffer[65]; 2277 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2278 // 2279 reverse_256(&ec_q[0], &buffer[1]); 2280 reverse_256(&ec_q[32], &buffer[33]); 2281 2282 #ifdef ENABLE_TESTING_SUPPORT 2283 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2284 log_info("testing_support: invalidating public key"); 2285 // flip single bit of public key coordinate 2286 buffer[1] ^= 1; 2287 } 2288 #endif 2289 2290 // stk generation method 2291 // passkey entry: notify app to show passkey or to request passkey 2292 switch (setup->sm_stk_generation_method){ 2293 case JUST_WORKS: 2294 case NUMERIC_COMPARISON: 2295 if (IS_RESPONDER(connection->sm_role)){ 2296 // responder 2297 sm_sc_start_calculating_local_confirm(connection); 2298 } else { 2299 // initiator 2300 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2301 } 2302 break; 2303 case PK_INIT_INPUT: 2304 case PK_RESP_INPUT: 2305 case PK_BOTH_INPUT: 2306 // use random TK for display 2307 memcpy(setup->sm_ra, setup->sm_tk, 16); 2308 memcpy(setup->sm_rb, setup->sm_tk, 16); 2309 setup->sm_passkey_bit = 0; 2310 2311 if (IS_RESPONDER(connection->sm_role)){ 2312 // responder 2313 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2314 } else { 2315 // initiator 2316 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2317 } 2318 trigger_user_response = 1; 2319 break; 2320 case OOB: 2321 if (IS_RESPONDER(connection->sm_role)){ 2322 // responder 2323 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2324 } else { 2325 // initiator 2326 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2327 } 2328 break; 2329 } 2330 2331 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2332 sm_timeout_reset(connection); 2333 2334 // trigger user response after sending pdu 2335 if (trigger_user_response){ 2336 sm_trigger_user_response(connection); 2337 } 2338 break; 2339 } 2340 case SM_SC_SEND_CONFIRMATION: { 2341 uint8_t buffer[17]; 2342 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2343 reverse_128(setup->sm_local_confirm, &buffer[1]); 2344 if (IS_RESPONDER(connection->sm_role)){ 2345 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2346 } else { 2347 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2348 } 2349 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2350 sm_timeout_reset(connection); 2351 break; 2352 } 2353 case SM_SC_SEND_PAIRING_RANDOM: { 2354 uint8_t buffer[17]; 2355 buffer[0] = SM_CODE_PAIRING_RANDOM; 2356 reverse_128(setup->sm_local_nonce, &buffer[1]); 2357 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2358 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2359 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2360 if (IS_RESPONDER(connection->sm_role)){ 2361 // responder 2362 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2363 } else { 2364 // initiator 2365 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2366 } 2367 } else { 2368 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2369 if (IS_RESPONDER(connection->sm_role)){ 2370 // responder 2371 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2372 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2373 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2374 } else { 2375 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2376 sm_sc_prepare_dhkey_check(connection); 2377 } 2378 } else { 2379 // initiator 2380 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2381 } 2382 } 2383 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2384 sm_timeout_reset(connection); 2385 break; 2386 } 2387 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2388 uint8_t buffer[17]; 2389 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2390 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2391 2392 if (IS_RESPONDER(connection->sm_role)){ 2393 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2394 } else { 2395 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2396 } 2397 2398 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2399 sm_timeout_reset(connection); 2400 break; 2401 } 2402 2403 #endif 2404 2405 #ifdef ENABLE_LE_PERIPHERAL 2406 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2407 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2408 2409 // start with initiator key dist flags 2410 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2411 2412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2413 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2414 if (setup->sm_use_secure_connections){ 2415 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2416 } 2417 #endif 2418 // setup in response 2419 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); 2420 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); 2421 2422 // update key distribution after ENC was dropped 2423 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2424 2425 if (setup->sm_use_secure_connections){ 2426 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2427 } else { 2428 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2429 } 2430 2431 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2432 sm_timeout_reset(connection); 2433 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2434 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2435 sm_trigger_user_response(connection); 2436 } 2437 return; 2438 #endif 2439 2440 case SM_PH2_SEND_PAIRING_RANDOM: { 2441 uint8_t buffer[17]; 2442 buffer[0] = SM_CODE_PAIRING_RANDOM; 2443 reverse_128(setup->sm_local_random, &buffer[1]); 2444 if (IS_RESPONDER(connection->sm_role)){ 2445 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2446 } else { 2447 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2448 } 2449 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2450 sm_timeout_reset(connection); 2451 break; 2452 } 2453 2454 case SM_PH2_C1_GET_ENC_A: 2455 // already busy? 2456 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2457 // calculate confirm using aes128 engine - step 1 2458 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); 2459 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2460 sm_aes128_state = SM_AES128_ACTIVE; 2461 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2462 break; 2463 2464 case SM_PH2_C1_GET_ENC_C: 2465 // already busy? 2466 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2467 // calculate m_confirm using aes128 engine - step 1 2468 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); 2469 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2470 sm_aes128_state = SM_AES128_ACTIVE; 2471 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2472 break; 2473 2474 case SM_PH2_CALC_STK: 2475 // already busy? 2476 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2477 // calculate STK 2478 if (IS_RESPONDER(connection->sm_role)){ 2479 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2480 } else { 2481 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2482 } 2483 connection->sm_engine_state = SM_PH2_W4_STK; 2484 sm_aes128_state = SM_AES128_ACTIVE; 2485 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2486 break; 2487 2488 case SM_PH3_Y_GET_ENC: 2489 // already busy? 2490 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2491 // PH3B2 - calculate Y from - enc 2492 // Y = dm(DHK, Rand) 2493 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2494 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2495 sm_aes128_state = SM_AES128_ACTIVE; 2496 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, connection); 2497 break; 2498 2499 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2500 uint8_t buffer[17]; 2501 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2502 reverse_128(setup->sm_local_confirm, &buffer[1]); 2503 if (IS_RESPONDER(connection->sm_role)){ 2504 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2505 } else { 2506 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2507 } 2508 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2509 sm_timeout_reset(connection); 2510 return; 2511 } 2512 #ifdef ENABLE_LE_PERIPHERAL 2513 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2514 sm_key_t stk_flipped; 2515 reverse_128(setup->sm_ltk, stk_flipped); 2516 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2517 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2518 return; 2519 } 2520 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2521 sm_key_t ltk_flipped; 2522 reverse_128(setup->sm_ltk, ltk_flipped); 2523 connection->sm_engine_state = SM_RESPONDER_IDLE; 2524 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2525 sm_done_for_handle(connection->sm_handle); 2526 return; 2527 } 2528 case SM_RESPONDER_PH4_Y_GET_ENC: 2529 // already busy? 2530 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2531 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2532 // Y = dm(DHK, Rand) 2533 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2534 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2535 sm_aes128_state = SM_AES128_ACTIVE; 2536 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, connection); 2537 return; 2538 #endif 2539 #ifdef ENABLE_LE_CENTRAL 2540 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2541 sm_key_t stk_flipped; 2542 reverse_128(setup->sm_ltk, stk_flipped); 2543 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2544 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2545 return; 2546 } 2547 #endif 2548 2549 case SM_PH3_DISTRIBUTE_KEYS: 2550 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2551 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2552 uint8_t buffer[17]; 2553 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2554 reverse_128(setup->sm_ltk, &buffer[1]); 2555 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2556 sm_timeout_reset(connection); 2557 return; 2558 } 2559 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2560 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2561 uint8_t buffer[11]; 2562 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2563 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2564 reverse_64(setup->sm_local_rand, &buffer[3]); 2565 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2566 sm_timeout_reset(connection); 2567 return; 2568 } 2569 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2570 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2571 uint8_t buffer[17]; 2572 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2573 reverse_128(sm_persistent_irk, &buffer[1]); 2574 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2575 sm_timeout_reset(connection); 2576 return; 2577 } 2578 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2579 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2580 bd_addr_t local_address; 2581 uint8_t buffer[8]; 2582 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2583 switch (gap_random_address_get_mode()){ 2584 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2585 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2586 // public or static random 2587 gap_le_get_own_address(&buffer[1], local_address); 2588 break; 2589 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2590 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2591 // fallback to public 2592 gap_local_bd_addr(local_address); 2593 buffer[1] = 0; 2594 break; 2595 } 2596 reverse_bd_addr(local_address, &buffer[2]); 2597 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2598 sm_timeout_reset(connection); 2599 return; 2600 } 2601 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2602 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2603 2604 // hack to reproduce test runs 2605 if (test_use_fixed_local_csrk){ 2606 memset(setup->sm_local_csrk, 0xcc, 16); 2607 } 2608 2609 uint8_t buffer[17]; 2610 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2611 reverse_128(setup->sm_local_csrk, &buffer[1]); 2612 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2613 sm_timeout_reset(connection); 2614 return; 2615 } 2616 2617 // keys are sent 2618 if (IS_RESPONDER(connection->sm_role)){ 2619 // slave -> receive master keys if any 2620 if (sm_key_distribution_all_received(connection)){ 2621 sm_key_distribution_handle_all_received(connection); 2622 connection->sm_engine_state = SM_RESPONDER_IDLE; 2623 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2624 sm_done_for_handle(connection->sm_handle); 2625 } else { 2626 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2627 } 2628 } else { 2629 // master -> all done 2630 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2631 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2632 sm_done_for_handle(connection->sm_handle); 2633 } 2634 break; 2635 2636 default: 2637 break; 2638 } 2639 2640 // check again if active connection was released 2641 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2642 } 2643 } 2644 2645 // sm_aes128_state stays active 2646 static void sm_handle_encryption_result_enc_a(void *arg){ 2647 sm_connection_t * connection = (sm_connection_t*) arg; 2648 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2649 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, connection); 2650 } 2651 2652 static void sm_handle_encryption_result_enc_b(void *arg){ 2653 sm_connection_t * connection = (sm_connection_t*) arg; 2654 sm_aes128_state = SM_AES128_IDLE; 2655 log_info_key("c1!", setup->sm_local_confirm); 2656 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2657 sm_run(); 2658 } 2659 2660 // sm_aes128_state stays active 2661 static void sm_handle_encryption_result_enc_c(void *arg){ 2662 sm_connection_t * connection = (sm_connection_t*) arg; 2663 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2664 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, connection); 2665 } 2666 2667 static void sm_handle_encryption_result_enc_d(void * arg){ 2668 sm_connection_t * connection = (sm_connection_t*) arg; 2669 sm_aes128_state = SM_AES128_IDLE; 2670 log_info_key("c1!", sm_aes128_ciphertext); 2671 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2672 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2673 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2674 sm_run(); 2675 return; 2676 } 2677 if (IS_RESPONDER(connection->sm_role)){ 2678 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2679 sm_run(); 2680 } else { 2681 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2682 sm_aes128_state = SM_AES128_ACTIVE; 2683 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2684 } 2685 } 2686 2687 static void sm_handle_encryption_result_enc_stk(void *arg){ 2688 sm_connection_t * connection = (sm_connection_t*) arg; 2689 sm_aes128_state = SM_AES128_IDLE; 2690 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2691 log_info_key("stk", setup->sm_ltk); 2692 if (IS_RESPONDER(connection->sm_role)){ 2693 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2694 } else { 2695 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2696 } 2697 sm_run(); 2698 } 2699 2700 // sm_aes128_state stays active 2701 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2702 sm_connection_t * connection = (sm_connection_t*) arg; 2703 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2704 log_info_hex16("y", setup->sm_local_y); 2705 // PH3B3 - calculate EDIV 2706 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2707 log_info_hex16("ediv", setup->sm_local_ediv); 2708 // PH3B4 - calculate LTK - enc 2709 // LTK = d1(ER, DIV, 0)) 2710 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2711 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, connection); 2712 } 2713 2714 #ifdef ENABLE_LE_PERIPHERAL 2715 // sm_aes128_state stays active 2716 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2717 sm_connection_t * connection = (sm_connection_t*) arg; 2718 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2719 log_info_hex16("y", setup->sm_local_y); 2720 2721 // PH3B3 - calculate DIV 2722 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2723 log_info_hex16("ediv", setup->sm_local_ediv); 2724 // PH3B4 - calculate LTK - enc 2725 // LTK = d1(ER, DIV, 0)) 2726 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2727 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, connection); 2728 } 2729 #endif 2730 2731 // sm_aes128_state stays active 2732 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2733 sm_connection_t * connection = (sm_connection_t*) arg; 2734 log_info_key("ltk", setup->sm_ltk); 2735 // calc CSRK next 2736 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2737 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, connection); 2738 } 2739 2740 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2741 sm_connection_t * connection = (sm_connection_t*) arg; 2742 sm_aes128_state = SM_AES128_IDLE; 2743 log_info_key("csrk", setup->sm_local_csrk); 2744 if (setup->sm_key_distribution_send_set){ 2745 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2746 } else { 2747 // no keys to send, just continue 2748 if (IS_RESPONDER(connection->sm_role)){ 2749 // slave -> receive master keys 2750 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2751 } else { 2752 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2753 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2754 } else { 2755 // master -> all done 2756 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2757 sm_done_for_handle(connection->sm_handle); 2758 } 2759 } 2760 } 2761 sm_run(); 2762 } 2763 2764 #ifdef ENABLE_LE_PERIPHERAL 2765 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2766 sm_connection_t * connection = (sm_connection_t*) arg; 2767 sm_aes128_state = SM_AES128_IDLE; 2768 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2769 log_info_key("ltk", setup->sm_ltk); 2770 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2771 sm_run(); 2772 } 2773 #endif 2774 2775 static void sm_handle_encryption_result_address_resolution(void *arg){ 2776 UNUSED(arg); 2777 sm_aes128_state = SM_AES128_IDLE; 2778 sm_address_resolution_ah_calculation_active = 0; 2779 // compare calulated address against connecting device 2780 uint8_t * hash = &sm_aes128_ciphertext[13]; 2781 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2782 log_info("LE Device Lookup: matched resolvable private address"); 2783 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2784 sm_run(); 2785 return; 2786 } 2787 // no match, try next 2788 sm_address_resolution_test++; 2789 sm_run(); 2790 } 2791 2792 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2793 UNUSED(arg); 2794 sm_aes128_state = SM_AES128_IDLE; 2795 log_info_key("irk", sm_persistent_irk); 2796 dkg_state = DKG_CALC_DHK; 2797 sm_run(); 2798 } 2799 2800 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2801 UNUSED(arg); 2802 sm_aes128_state = SM_AES128_IDLE; 2803 log_info_key("dhk", sm_persistent_dhk); 2804 dkg_state = DKG_READY; 2805 sm_run(); 2806 } 2807 2808 static void sm_handle_encryption_result_rau(void *arg){ 2809 UNUSED(arg); 2810 sm_aes128_state = SM_AES128_IDLE; 2811 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2812 rau_state = RAU_SET_ADDRESS; 2813 sm_run(); 2814 } 2815 2816 static void sm_handle_random_result_rau(void * arg){ 2817 UNUSED(arg); 2818 // non-resolvable vs. resolvable 2819 switch (gap_random_adress_type){ 2820 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2821 // resolvable: use random as prand and calc address hash 2822 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2823 sm_random_address[0] &= 0x3f; 2824 sm_random_address[0] |= 0x40; 2825 rau_state = RAU_GET_ENC; 2826 break; 2827 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2828 default: 2829 // "The two most significant bits of the address shall be equal to ‘0’"" 2830 sm_random_address[0] &= 0x3f; 2831 rau_state = RAU_SET_ADDRESS; 2832 break; 2833 } 2834 sm_run(); 2835 } 2836 2837 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2838 static void sm_handle_random_result_sc_get_random(void * arg){ 2839 sm_connection_t * connection = (sm_connection_t*) arg; 2840 2841 // OOB 2842 if (setup->sm_stk_generation_method == OOB){ 2843 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2844 sm_run(); 2845 return; 2846 } 2847 2848 // initiator & jw/nc -> send pairing random 2849 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2850 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2851 } else { 2852 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2853 } 2854 sm_run(); 2855 } 2856 #endif 2857 2858 static void sm_handle_random_result_ph2_random(void * arg){ 2859 sm_connection_t * connection = (sm_connection_t*) arg; 2860 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2861 sm_run(); 2862 } 2863 2864 static void sm_handle_random_result_ph2_tk(void * arg){ 2865 sm_connection_t * connection = (sm_connection_t*) arg; 2866 sm_reset_tk(); 2867 uint32_t tk; 2868 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2869 // map random to 0-999999 without speding much cycles on a modulus operation 2870 tk = little_endian_read_32(sm_random_data,0); 2871 tk = tk & 0xfffff; // 1048575 2872 if (tk >= 999999){ 2873 tk = tk - 999999; 2874 } 2875 } else { 2876 // override with pre-defined passkey 2877 tk = sm_fixed_passkey_in_display_role; 2878 } 2879 big_endian_store_32(setup->sm_tk, 12, tk); 2880 if (IS_RESPONDER(connection->sm_role)){ 2881 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2882 } else { 2883 if (setup->sm_use_secure_connections){ 2884 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2885 } else { 2886 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2887 sm_trigger_user_response(connection); 2888 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2889 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2890 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2891 } 2892 } 2893 } 2894 sm_run(); 2895 } 2896 2897 static void sm_handle_random_result_ph3_div(void * arg){ 2898 sm_connection_t * connection = (sm_connection_t*) arg; 2899 // use 16 bit from random value as div 2900 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2901 log_info_hex16("div", setup->sm_local_div); 2902 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2903 sm_run(); 2904 } 2905 2906 static void sm_handle_random_result_ph3_random(void * arg){ 2907 sm_connection_t * connection = (sm_connection_t*) arg; 2908 reverse_64(sm_random_data, setup->sm_local_rand); 2909 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2910 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2911 // no db for authenticated flag hack: store flag in bit 4 of LSB 2912 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2913 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2914 } 2915 static void sm_validate_er_ir(void){ 2916 // warn about default ER/IR 2917 int warning = 0; 2918 if (sm_ir_is_default()){ 2919 warning = 1; 2920 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 2921 } 2922 if (sm_er_is_default()){ 2923 warning = 1; 2924 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 2925 } 2926 if (warning) { 2927 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 2928 } 2929 } 2930 2931 static void sm_handle_random_result_ir(void *arg){ 2932 sm_persistent_keys_random_active = 0; 2933 if (arg){ 2934 // key generated, store in tlv 2935 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2936 log_info("Generated IR key. Store in TLV status: %d", status); 2937 } 2938 log_info_key("IR", sm_persistent_ir); 2939 dkg_state = DKG_CALC_IRK; 2940 sm_run(); 2941 } 2942 2943 static void sm_handle_random_result_er(void *arg){ 2944 sm_persistent_keys_random_active = 0; 2945 if (arg){ 2946 // key generated, store in tlv 2947 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2948 log_info("Generated ER key. Store in TLV status: %d", status); 2949 } 2950 log_info_key("ER", sm_persistent_er); 2951 2952 // try load ir 2953 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2954 if (key_size == 16){ 2955 // ok, let's continue 2956 log_info("IR from TLV"); 2957 sm_handle_random_result_ir( NULL ); 2958 } else { 2959 // invalid, generate new random one 2960 sm_persistent_keys_random_active = 1; 2961 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 2962 } 2963 } 2964 2965 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2966 2967 UNUSED(channel); // ok: there is no channel 2968 UNUSED(size); // ok: fixed format HCI events 2969 2970 sm_connection_t * sm_conn; 2971 hci_con_handle_t con_handle; 2972 2973 switch (packet_type) { 2974 2975 case HCI_EVENT_PACKET: 2976 switch (hci_event_packet_get_type(packet)) { 2977 2978 case BTSTACK_EVENT_STATE: 2979 // bt stack activated, get started 2980 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2981 log_info("HCI Working!"); 2982 2983 // setup IR/ER with TLV 2984 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 2985 if (sm_tlv_impl){ 2986 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2987 if (key_size == 16){ 2988 // ok, let's continue 2989 log_info("ER from TLV"); 2990 sm_handle_random_result_er( NULL ); 2991 } else { 2992 // invalid, generate random one 2993 sm_persistent_keys_random_active = 1; 2994 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 2995 } 2996 } else { 2997 sm_validate_er_ir(); 2998 dkg_state = DKG_CALC_IRK; 2999 } 3000 } 3001 break; 3002 3003 case HCI_EVENT_LE_META: 3004 switch (packet[2]) { 3005 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3006 3007 log_info("sm: connected"); 3008 3009 if (packet[3]) return; // connection failed 3010 3011 con_handle = little_endian_read_16(packet, 4); 3012 sm_conn = sm_get_connection_for_handle(con_handle); 3013 if (!sm_conn) break; 3014 3015 sm_conn->sm_handle = con_handle; 3016 sm_conn->sm_role = packet[6]; 3017 sm_conn->sm_peer_addr_type = packet[7]; 3018 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3019 3020 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3021 3022 // reset security properties 3023 sm_conn->sm_connection_encrypted = 0; 3024 sm_conn->sm_connection_authenticated = 0; 3025 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3026 sm_conn->sm_le_db_index = -1; 3027 3028 // prepare CSRK lookup (does not involve setup) 3029 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3030 3031 // just connected -> everything else happens in sm_run() 3032 if (IS_RESPONDER(sm_conn->sm_role)){ 3033 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3034 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3035 if (sm_slave_request_security) { 3036 // request security if requested by app 3037 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3038 } else { 3039 // otherwise, wait for pairing request 3040 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3041 } 3042 } 3043 break; 3044 } else { 3045 // master 3046 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3047 } 3048 break; 3049 3050 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3051 con_handle = little_endian_read_16(packet, 3); 3052 sm_conn = sm_get_connection_for_handle(con_handle); 3053 if (!sm_conn) break; 3054 3055 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3056 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3057 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3058 break; 3059 } 3060 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3061 // PH2 SEND LTK as we need to exchange keys in PH3 3062 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3063 break; 3064 } 3065 3066 // store rand and ediv 3067 reverse_64(&packet[5], sm_conn->sm_local_rand); 3068 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3069 3070 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3071 // potentially stored LTK is from the master 3072 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3073 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3074 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3075 break; 3076 } 3077 // additionally check if remote is in LE Device DB if requested 3078 switch(sm_conn->sm_irk_lookup_state){ 3079 case IRK_LOOKUP_FAILED: 3080 log_info("LTK Request: device not in device db"); 3081 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3082 break; 3083 case IRK_LOOKUP_SUCCEEDED: 3084 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3085 break; 3086 default: 3087 // wait for irk look doen 3088 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3089 break; 3090 } 3091 break; 3092 } 3093 3094 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3095 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3096 #else 3097 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3098 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3099 #endif 3100 break; 3101 3102 default: 3103 break; 3104 } 3105 break; 3106 3107 case HCI_EVENT_ENCRYPTION_CHANGE: 3108 con_handle = little_endian_read_16(packet, 3); 3109 sm_conn = sm_get_connection_for_handle(con_handle); 3110 if (!sm_conn) break; 3111 3112 sm_conn->sm_connection_encrypted = packet[5]; 3113 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3114 sm_conn->sm_actual_encryption_key_size); 3115 log_info("event handler, state %u", sm_conn->sm_engine_state); 3116 3117 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3118 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3119 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3120 // notify client, if pairing was requested before 3121 if (sm_conn->sm_pairing_requested){ 3122 sm_conn->sm_pairing_requested = 0; 3123 if (sm_conn->sm_connection_encrypted){ 3124 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3125 } else { 3126 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3127 } 3128 } 3129 sm_done_for_handle(sm_conn->sm_handle); 3130 break; 3131 } 3132 3133 if (!sm_conn->sm_connection_encrypted) break; 3134 3135 // continue pairing 3136 switch (sm_conn->sm_engine_state){ 3137 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3138 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3139 sm_done_for_handle(sm_conn->sm_handle); 3140 break; 3141 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3142 if (IS_RESPONDER(sm_conn->sm_role)){ 3143 // slave 3144 if (setup->sm_use_secure_connections){ 3145 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3146 } else { 3147 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3148 } 3149 } else { 3150 // master 3151 if (sm_key_distribution_all_received(sm_conn)){ 3152 // skip receiving keys as there are none 3153 sm_key_distribution_handle_all_received(sm_conn); 3154 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3155 } else { 3156 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3157 } 3158 } 3159 break; 3160 default: 3161 break; 3162 } 3163 break; 3164 3165 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3166 con_handle = little_endian_read_16(packet, 3); 3167 sm_conn = sm_get_connection_for_handle(con_handle); 3168 if (!sm_conn) break; 3169 3170 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3171 log_info("event handler, state %u", sm_conn->sm_engine_state); 3172 // continue if part of initial pairing 3173 switch (sm_conn->sm_engine_state){ 3174 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3175 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3176 sm_done_for_handle(sm_conn->sm_handle); 3177 break; 3178 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3179 if (IS_RESPONDER(sm_conn->sm_role)){ 3180 // slave 3181 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3182 } else { 3183 // master 3184 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3185 } 3186 break; 3187 default: 3188 break; 3189 } 3190 break; 3191 3192 3193 case HCI_EVENT_DISCONNECTION_COMPLETE: 3194 con_handle = little_endian_read_16(packet, 3); 3195 sm_done_for_handle(con_handle); 3196 sm_conn = sm_get_connection_for_handle(con_handle); 3197 if (!sm_conn) break; 3198 3199 // delete stored bonding on disconnect with authentication failure in ph0 3200 if (sm_conn->sm_role == 0 3201 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3202 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3203 le_device_db_remove(sm_conn->sm_le_db_index); 3204 } 3205 3206 // pairing failed, if it was ongoing 3207 if (sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED && sm_conn->sm_engine_state != SM_GENERAL_IDLE){ 3208 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3209 } 3210 3211 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3212 sm_conn->sm_handle = 0; 3213 break; 3214 3215 case HCI_EVENT_COMMAND_COMPLETE: 3216 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3217 // set local addr for le device db 3218 bd_addr_t addr; 3219 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3220 le_device_db_set_local_bd_addr(addr); 3221 } 3222 break; 3223 default: 3224 break; 3225 } 3226 break; 3227 default: 3228 break; 3229 } 3230 3231 sm_run(); 3232 } 3233 3234 static inline int sm_calc_actual_encryption_key_size(int other){ 3235 if (other < sm_min_encryption_key_size) return 0; 3236 if (other < sm_max_encryption_key_size) return other; 3237 return sm_max_encryption_key_size; 3238 } 3239 3240 3241 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3242 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3243 switch (method){ 3244 case JUST_WORKS: 3245 case NUMERIC_COMPARISON: 3246 return 1; 3247 default: 3248 return 0; 3249 } 3250 } 3251 // responder 3252 3253 static int sm_passkey_used(stk_generation_method_t method){ 3254 switch (method){ 3255 case PK_RESP_INPUT: 3256 return 1; 3257 default: 3258 return 0; 3259 } 3260 } 3261 3262 static int sm_passkey_entry(stk_generation_method_t method){ 3263 switch (method){ 3264 case PK_RESP_INPUT: 3265 case PK_INIT_INPUT: 3266 case PK_BOTH_INPUT: 3267 return 1; 3268 default: 3269 return 0; 3270 } 3271 } 3272 3273 #endif 3274 3275 /** 3276 * @return ok 3277 */ 3278 static int sm_validate_stk_generation_method(void){ 3279 // check if STK generation method is acceptable by client 3280 switch (setup->sm_stk_generation_method){ 3281 case JUST_WORKS: 3282 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3283 case PK_RESP_INPUT: 3284 case PK_INIT_INPUT: 3285 case PK_BOTH_INPUT: 3286 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3287 case OOB: 3288 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3289 case NUMERIC_COMPARISON: 3290 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3291 default: 3292 return 0; 3293 } 3294 } 3295 3296 // size of complete sm_pdu used to validate input 3297 static const uint8_t sm_pdu_size[] = { 3298 0, // 0x00 invalid opcode 3299 7, // 0x01 pairing request 3300 7, // 0x02 pairing response 3301 17, // 0x03 pairing confirm 3302 17, // 0x04 pairing random 3303 2, // 0x05 pairing failed 3304 17, // 0x06 encryption information 3305 11, // 0x07 master identification 3306 17, // 0x08 identification information 3307 8, // 0x09 identify address information 3308 17, // 0x0a signing information 3309 2, // 0x0b security request 3310 65, // 0x0c pairing public key 3311 17, // 0x0d pairing dhk check 3312 2, // 0x0e keypress notification 3313 }; 3314 3315 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3316 3317 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3318 sm_run(); 3319 } 3320 3321 if (packet_type != SM_DATA_PACKET) return; 3322 if (size == 0) return; 3323 3324 uint8_t sm_pdu_code = packet[0]; 3325 3326 // validate pdu size 3327 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3328 if (sm_pdu_size[sm_pdu_code] != size) return; 3329 3330 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3331 if (!sm_conn) return; 3332 3333 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3334 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3335 sm_done_for_handle(con_handle); 3336 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3337 return; 3338 } 3339 3340 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3341 3342 int err; 3343 UNUSED(err); 3344 3345 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3346 uint8_t buffer[5]; 3347 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3348 buffer[1] = 3; 3349 little_endian_store_16(buffer, 2, con_handle); 3350 buffer[4] = packet[1]; 3351 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3352 return; 3353 } 3354 3355 switch (sm_conn->sm_engine_state){ 3356 3357 // a sm timeout requries a new physical connection 3358 case SM_GENERAL_TIMEOUT: 3359 return; 3360 3361 #ifdef ENABLE_LE_CENTRAL 3362 3363 // Initiator 3364 case SM_INITIATOR_CONNECTED: 3365 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3366 sm_pdu_received_in_wrong_state(sm_conn); 3367 break; 3368 } 3369 3370 // IRK complete? 3371 switch (sm_conn->sm_irk_lookup_state){ 3372 case IRK_LOOKUP_FAILED: 3373 case IRK_LOOKUP_SUCCEEDED: 3374 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3375 break; 3376 default: 3377 break; 3378 } 3379 3380 // otherwise, store security request 3381 sm_conn->sm_security_request_received = 1; 3382 break; 3383 3384 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3385 // Core 5, Vol 3, Part H, 2.4.6: 3386 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3387 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3388 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3389 log_info("Ignoring Security Request"); 3390 break; 3391 } 3392 3393 // all other pdus are incorrect 3394 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3395 sm_pdu_received_in_wrong_state(sm_conn); 3396 break; 3397 } 3398 3399 // store pairing request 3400 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3401 err = sm_stk_generation_init(sm_conn); 3402 3403 #ifdef ENABLE_TESTING_SUPPORT 3404 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3405 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3406 err = test_pairing_failure; 3407 } 3408 #endif 3409 3410 if (err){ 3411 setup->sm_pairing_failed_reason = err; 3412 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3413 break; 3414 } 3415 3416 // generate random number first, if we need to show passkey 3417 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3418 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3419 break; 3420 } 3421 3422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3423 if (setup->sm_use_secure_connections){ 3424 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3425 if (setup->sm_stk_generation_method == JUST_WORKS){ 3426 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3427 sm_trigger_user_response(sm_conn); 3428 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3429 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3430 } 3431 } else { 3432 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3433 } 3434 break; 3435 } 3436 #endif 3437 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3438 sm_trigger_user_response(sm_conn); 3439 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3440 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3441 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3442 } 3443 break; 3444 3445 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3446 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3447 sm_pdu_received_in_wrong_state(sm_conn); 3448 break; 3449 } 3450 3451 // store s_confirm 3452 reverse_128(&packet[1], setup->sm_peer_confirm); 3453 3454 #ifdef ENABLE_TESTING_SUPPORT 3455 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3456 log_info("testing_support: reset confirm value"); 3457 memset(setup->sm_peer_confirm, 0, 16); 3458 } 3459 #endif 3460 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3461 break; 3462 3463 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3464 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3465 sm_pdu_received_in_wrong_state(sm_conn); 3466 break;; 3467 } 3468 3469 // received random value 3470 reverse_128(&packet[1], setup->sm_peer_random); 3471 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3472 break; 3473 #endif 3474 3475 #ifdef ENABLE_LE_PERIPHERAL 3476 // Responder 3477 case SM_RESPONDER_IDLE: 3478 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3479 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3480 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3481 sm_pdu_received_in_wrong_state(sm_conn); 3482 break;; 3483 } 3484 3485 // store pairing request 3486 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3487 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3488 break; 3489 #endif 3490 3491 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3492 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3493 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3494 sm_pdu_received_in_wrong_state(sm_conn); 3495 break; 3496 } 3497 3498 // store public key for DH Key calculation 3499 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3500 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3501 3502 // validate public key 3503 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3504 if (err){ 3505 log_error("sm: peer public key invalid %x", err); 3506 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3507 break; 3508 } 3509 3510 // start calculating dhkey 3511 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3512 3513 3514 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3515 if (IS_RESPONDER(sm_conn->sm_role)){ 3516 // responder 3517 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3518 } else { 3519 // initiator 3520 // stk generation method 3521 // passkey entry: notify app to show passkey or to request passkey 3522 switch (setup->sm_stk_generation_method){ 3523 case JUST_WORKS: 3524 case NUMERIC_COMPARISON: 3525 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3526 break; 3527 case PK_RESP_INPUT: 3528 sm_sc_start_calculating_local_confirm(sm_conn); 3529 break; 3530 case PK_INIT_INPUT: 3531 case PK_BOTH_INPUT: 3532 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3533 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3534 break; 3535 } 3536 sm_sc_start_calculating_local_confirm(sm_conn); 3537 break; 3538 case OOB: 3539 // generate Nx 3540 log_info("Generate Na"); 3541 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3542 break; 3543 } 3544 } 3545 break; 3546 3547 case SM_SC_W4_CONFIRMATION: 3548 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3549 sm_pdu_received_in_wrong_state(sm_conn); 3550 break; 3551 } 3552 // received confirm value 3553 reverse_128(&packet[1], setup->sm_peer_confirm); 3554 3555 #ifdef ENABLE_TESTING_SUPPORT 3556 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3557 log_info("testing_support: reset confirm value"); 3558 memset(setup->sm_peer_confirm, 0, 16); 3559 } 3560 #endif 3561 if (IS_RESPONDER(sm_conn->sm_role)){ 3562 // responder 3563 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3564 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3565 // still waiting for passkey 3566 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3567 break; 3568 } 3569 } 3570 sm_sc_start_calculating_local_confirm(sm_conn); 3571 } else { 3572 // initiator 3573 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3574 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3575 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3576 } else { 3577 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3578 } 3579 } 3580 break; 3581 3582 case SM_SC_W4_PAIRING_RANDOM: 3583 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3584 sm_pdu_received_in_wrong_state(sm_conn); 3585 break; 3586 } 3587 3588 // received random value 3589 reverse_128(&packet[1], setup->sm_peer_nonce); 3590 3591 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3592 // only check for JUST WORK/NC in initiator role OR passkey entry 3593 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3594 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3595 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3596 break; 3597 } 3598 3599 // OOB 3600 if (setup->sm_stk_generation_method == OOB){ 3601 3602 // setup local random, set to zero if remote did not receive our data 3603 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3604 if (IS_RESPONDER(sm_conn->sm_role)){ 3605 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3606 log_info("Reset rb as A does not have OOB data"); 3607 memset(setup->sm_rb, 0, 16); 3608 } else { 3609 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3610 log_info("Use stored rb"); 3611 log_info_hexdump(setup->sm_rb, 16); 3612 } 3613 } else { 3614 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3615 log_info("Reset ra as B does not have OOB data"); 3616 memset(setup->sm_ra, 0, 16); 3617 } else { 3618 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3619 log_info("Use stored ra"); 3620 log_info_hexdump(setup->sm_ra, 16); 3621 } 3622 } 3623 3624 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3625 if (setup->sm_have_oob_data){ 3626 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3627 break; 3628 } 3629 } 3630 3631 // TODO: we only get here for Responder role with JW/NC 3632 sm_sc_state_after_receiving_random(sm_conn); 3633 break; 3634 3635 case SM_SC_W2_CALCULATE_G2: 3636 case SM_SC_W4_CALCULATE_G2: 3637 case SM_SC_W4_CALCULATE_DHKEY: 3638 case SM_SC_W2_CALCULATE_F5_SALT: 3639 case SM_SC_W4_CALCULATE_F5_SALT: 3640 case SM_SC_W2_CALCULATE_F5_MACKEY: 3641 case SM_SC_W4_CALCULATE_F5_MACKEY: 3642 case SM_SC_W2_CALCULATE_F5_LTK: 3643 case SM_SC_W4_CALCULATE_F5_LTK: 3644 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3645 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3646 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3647 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3648 sm_pdu_received_in_wrong_state(sm_conn); 3649 break; 3650 } 3651 // store DHKey Check 3652 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3653 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3654 3655 // have we been only waiting for dhkey check command? 3656 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3657 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3658 } 3659 break; 3660 #endif 3661 3662 #ifdef ENABLE_LE_PERIPHERAL 3663 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3664 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3665 sm_pdu_received_in_wrong_state(sm_conn); 3666 break; 3667 } 3668 3669 // received confirm value 3670 reverse_128(&packet[1], setup->sm_peer_confirm); 3671 3672 #ifdef ENABLE_TESTING_SUPPORT 3673 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3674 log_info("testing_support: reset confirm value"); 3675 memset(setup->sm_peer_confirm, 0, 16); 3676 } 3677 #endif 3678 // notify client to hide shown passkey 3679 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3680 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3681 } 3682 3683 // handle user cancel pairing? 3684 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3685 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3686 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3687 break; 3688 } 3689 3690 // wait for user action? 3691 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3692 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3693 break; 3694 } 3695 3696 // calculate and send local_confirm 3697 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3698 break; 3699 3700 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3701 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3702 sm_pdu_received_in_wrong_state(sm_conn); 3703 break;; 3704 } 3705 3706 // received random value 3707 reverse_128(&packet[1], setup->sm_peer_random); 3708 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3709 break; 3710 #endif 3711 3712 case SM_PH3_RECEIVE_KEYS: 3713 switch(sm_pdu_code){ 3714 case SM_CODE_ENCRYPTION_INFORMATION: 3715 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3716 reverse_128(&packet[1], setup->sm_peer_ltk); 3717 break; 3718 3719 case SM_CODE_MASTER_IDENTIFICATION: 3720 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3721 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3722 reverse_64(&packet[3], setup->sm_peer_rand); 3723 break; 3724 3725 case SM_CODE_IDENTITY_INFORMATION: 3726 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3727 reverse_128(&packet[1], setup->sm_peer_irk); 3728 break; 3729 3730 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3731 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3732 setup->sm_peer_addr_type = packet[1]; 3733 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3734 break; 3735 3736 case SM_CODE_SIGNING_INFORMATION: 3737 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3738 reverse_128(&packet[1], setup->sm_peer_csrk); 3739 break; 3740 default: 3741 // Unexpected PDU 3742 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3743 break; 3744 } 3745 // done with key distribution? 3746 if (sm_key_distribution_all_received(sm_conn)){ 3747 3748 sm_key_distribution_handle_all_received(sm_conn); 3749 3750 if (IS_RESPONDER(sm_conn->sm_role)){ 3751 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3752 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3753 } else { 3754 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3755 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3756 sm_done_for_handle(sm_conn->sm_handle); 3757 } 3758 } else { 3759 if (setup->sm_use_secure_connections){ 3760 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3761 } else { 3762 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3763 } 3764 } 3765 } 3766 break; 3767 default: 3768 // Unexpected PDU 3769 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3770 break; 3771 } 3772 3773 // try to send preparared packet 3774 sm_run(); 3775 } 3776 3777 // Security Manager Client API 3778 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3779 sm_get_oob_data = get_oob_data_callback; 3780 } 3781 3782 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)){ 3783 sm_get_sc_oob_data = get_sc_oob_data_callback; 3784 } 3785 3786 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3787 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3788 } 3789 3790 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3791 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3792 } 3793 3794 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3795 sm_min_encryption_key_size = min_size; 3796 sm_max_encryption_key_size = max_size; 3797 } 3798 3799 void sm_set_authentication_requirements(uint8_t auth_req){ 3800 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3801 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3802 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3803 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3804 } 3805 #endif 3806 sm_auth_req = auth_req; 3807 } 3808 3809 void sm_set_io_capabilities(io_capability_t io_capability){ 3810 sm_io_capabilities = io_capability; 3811 } 3812 3813 #ifdef ENABLE_LE_PERIPHERAL 3814 void sm_set_request_security(int enable){ 3815 sm_slave_request_security = enable; 3816 } 3817 #endif 3818 3819 void sm_set_er(sm_key_t er){ 3820 memcpy(sm_persistent_er, er, 16); 3821 } 3822 3823 void sm_set_ir(sm_key_t ir){ 3824 memcpy(sm_persistent_ir, ir, 16); 3825 } 3826 3827 // Testing support only 3828 void sm_test_set_irk(sm_key_t irk){ 3829 memcpy(sm_persistent_irk, irk, 16); 3830 dkg_state = DKG_CALC_DHK; 3831 } 3832 3833 void sm_test_use_fixed_local_csrk(void){ 3834 test_use_fixed_local_csrk = 1; 3835 } 3836 3837 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3838 static void sm_ec_generated(void * arg){ 3839 UNUSED(arg); 3840 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3841 // trigger pairing if pending for ec key 3842 sm_run(); 3843 } 3844 static void sm_ec_generate_new_key(void){ 3845 log_info("sm: generate new ec key"); 3846 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3847 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3848 } 3849 #endif 3850 3851 #ifdef ENABLE_TESTING_SUPPORT 3852 void sm_test_set_pairing_failure(int reason){ 3853 test_pairing_failure = reason; 3854 } 3855 #endif 3856 3857 void sm_init(void){ 3858 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3859 sm_er_ir_set_default(); 3860 3861 // defaults 3862 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3863 | SM_STK_GENERATION_METHOD_OOB 3864 | SM_STK_GENERATION_METHOD_PASSKEY 3865 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3866 3867 sm_max_encryption_key_size = 16; 3868 sm_min_encryption_key_size = 7; 3869 3870 sm_fixed_passkey_in_display_role = 0xffffffff; 3871 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3872 3873 #ifdef USE_CMAC_ENGINE 3874 sm_cmac_active = 0; 3875 #endif 3876 dkg_state = DKG_W4_WORKING; 3877 rau_state = RAU_IDLE; 3878 sm_aes128_state = SM_AES128_IDLE; 3879 sm_address_resolution_test = -1; // no private address to resolve yet 3880 sm_address_resolution_ah_calculation_active = 0; 3881 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3882 sm_address_resolution_general_queue = NULL; 3883 3884 gap_random_adress_update_period = 15 * 60 * 1000L; 3885 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3886 3887 test_use_fixed_local_csrk = 0; 3888 3889 // register for HCI Events from HCI 3890 hci_event_callback_registration.callback = &sm_event_packet_handler; 3891 hci_add_event_handler(&hci_event_callback_registration); 3892 3893 // 3894 btstack_crypto_init(); 3895 3896 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3897 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3898 3899 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3900 sm_ec_generate_new_key(); 3901 #endif 3902 } 3903 3904 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3905 sm_fixed_passkey_in_display_role = passkey; 3906 } 3907 3908 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3909 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3910 } 3911 3912 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3913 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3914 if (!hci_con) return NULL; 3915 return &hci_con->sm_connection; 3916 } 3917 3918 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3919 switch (sm_conn->sm_engine_state){ 3920 case SM_GENERAL_IDLE: 3921 case SM_RESPONDER_IDLE: 3922 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3923 sm_run(); 3924 break; 3925 default: 3926 break; 3927 } 3928 } 3929 3930 /** 3931 * @brief Trigger Security Request 3932 */ 3933 void sm_send_security_request(hci_con_handle_t con_handle){ 3934 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3935 if (!sm_conn) return; 3936 sm_send_security_request_for_connection(sm_conn); 3937 } 3938 3939 // request pairing 3940 void sm_request_pairing(hci_con_handle_t con_handle){ 3941 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3942 if (!sm_conn) return; // wrong connection 3943 3944 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3945 if (IS_RESPONDER(sm_conn->sm_role)){ 3946 sm_send_security_request_for_connection(sm_conn); 3947 } else { 3948 // used as a trigger to start central/master/initiator security procedures 3949 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3950 uint8_t ltk[16]; 3951 switch (sm_conn->sm_irk_lookup_state){ 3952 case IRK_LOOKUP_SUCCEEDED: 3953 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 3954 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3955 int have_ltk = !sm_is_null_key(ltk); 3956 log_info("have ltk %u", have_ltk); 3957 // trigger 'pairing complete' event on encryption change 3958 sm_conn->sm_pairing_requested = 1; 3959 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3960 break; 3961 #endif 3962 /* explicit fall-through */ 3963 3964 case IRK_LOOKUP_FAILED: 3965 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3966 break; 3967 default: 3968 log_info("irk lookup pending"); 3969 sm_conn->sm_pairing_requested = 1; 3970 break; 3971 } 3972 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3973 sm_conn->sm_pairing_requested = 1; 3974 } 3975 } 3976 sm_run(); 3977 } 3978 3979 // called by client app on authorization request 3980 void sm_authorization_decline(hci_con_handle_t con_handle){ 3981 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3982 if (!sm_conn) return; // wrong connection 3983 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3984 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3985 } 3986 3987 void sm_authorization_grant(hci_con_handle_t con_handle){ 3988 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3989 if (!sm_conn) return; // wrong connection 3990 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3991 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3992 } 3993 3994 // GAP Bonding API 3995 3996 void sm_bonding_decline(hci_con_handle_t con_handle){ 3997 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3998 if (!sm_conn) return; // wrong connection 3999 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4000 log_info("decline, state %u", sm_conn->sm_engine_state); 4001 switch(sm_conn->sm_engine_state){ 4002 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4003 case SM_SC_W4_USER_RESPONSE: 4004 case SM_SC_W4_CONFIRMATION: 4005 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4006 #endif 4007 case SM_PH1_W4_USER_RESPONSE: 4008 switch (setup->sm_stk_generation_method){ 4009 case PK_RESP_INPUT: 4010 case PK_INIT_INPUT: 4011 case PK_BOTH_INPUT: 4012 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4013 break; 4014 case NUMERIC_COMPARISON: 4015 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4016 break; 4017 case JUST_WORKS: 4018 case OOB: 4019 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4020 break; 4021 } 4022 break; 4023 default: 4024 break; 4025 } 4026 sm_run(); 4027 } 4028 4029 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4030 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4031 if (!sm_conn) return; // wrong connection 4032 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4033 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4034 if (setup->sm_use_secure_connections){ 4035 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4036 } else { 4037 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4038 } 4039 } 4040 4041 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4042 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4043 sm_sc_prepare_dhkey_check(sm_conn); 4044 } 4045 #endif 4046 4047 sm_run(); 4048 } 4049 4050 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4051 // for now, it's the same 4052 sm_just_works_confirm(con_handle); 4053 } 4054 4055 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4056 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4057 if (!sm_conn) return; // wrong connection 4058 sm_reset_tk(); 4059 big_endian_store_32(setup->sm_tk, 12, passkey); 4060 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4061 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4062 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4063 } 4064 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4065 memcpy(setup->sm_ra, setup->sm_tk, 16); 4066 memcpy(setup->sm_rb, setup->sm_tk, 16); 4067 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4068 sm_sc_start_calculating_local_confirm(sm_conn); 4069 } 4070 #endif 4071 sm_run(); 4072 } 4073 4074 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4075 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4076 if (!sm_conn) return; // wrong connection 4077 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4078 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4079 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4080 switch (action){ 4081 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4082 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4083 flags |= (1 << action); 4084 break; 4085 case SM_KEYPRESS_PASSKEY_CLEARED: 4086 // clear counter, keypress & erased flags + set passkey cleared 4087 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4088 break; 4089 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4090 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4091 // erase actions queued 4092 num_actions--; 4093 if (num_actions == 0){ 4094 // clear counter, keypress & erased flags 4095 flags &= 0x19; 4096 } 4097 break; 4098 } 4099 num_actions++; 4100 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4101 break; 4102 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4103 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4104 // enter actions queued 4105 num_actions--; 4106 if (num_actions == 0){ 4107 // clear counter, keypress & erased flags 4108 flags &= 0x19; 4109 } 4110 break; 4111 } 4112 num_actions++; 4113 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4114 break; 4115 default: 4116 break; 4117 } 4118 setup->sm_keypress_notification = (num_actions << 5) | flags; 4119 sm_run(); 4120 } 4121 4122 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4123 static void sm_handle_random_result_oob(void * arg){ 4124 UNUSED(arg); 4125 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4126 sm_run(); 4127 } 4128 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4129 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4130 sm_sc_oob_callback = callback; 4131 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4132 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4133 return 0; 4134 } 4135 #endif 4136 4137 /** 4138 * @brief Identify device in LE Device DB 4139 * @param handle 4140 * @returns index from le_device_db or -1 if not found/identified 4141 */ 4142 int sm_le_device_index(hci_con_handle_t con_handle ){ 4143 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4144 if (!sm_conn) return -1; 4145 return sm_conn->sm_le_db_index; 4146 } 4147 4148 static int gap_random_address_type_requires_updates(void){ 4149 switch (gap_random_adress_type){ 4150 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4151 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4152 return 0; 4153 default: 4154 return 1; 4155 } 4156 } 4157 4158 static uint8_t own_address_type(void){ 4159 switch (gap_random_adress_type){ 4160 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4161 return BD_ADDR_TYPE_LE_PUBLIC; 4162 default: 4163 return BD_ADDR_TYPE_LE_RANDOM; 4164 } 4165 } 4166 4167 // GAP LE API 4168 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4169 gap_random_address_update_stop(); 4170 gap_random_adress_type = random_address_type; 4171 hci_le_set_own_address_type(own_address_type()); 4172 if (!gap_random_address_type_requires_updates()) return; 4173 gap_random_address_update_start(); 4174 gap_random_address_trigger(); 4175 } 4176 4177 gap_random_address_type_t gap_random_address_get_mode(void){ 4178 return gap_random_adress_type; 4179 } 4180 4181 void gap_random_address_set_update_period(int period_ms){ 4182 gap_random_adress_update_period = period_ms; 4183 if (!gap_random_address_type_requires_updates()) return; 4184 gap_random_address_update_stop(); 4185 gap_random_address_update_start(); 4186 } 4187 4188 void gap_random_address_set(bd_addr_t addr){ 4189 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4190 memcpy(sm_random_address, addr, 6); 4191 rau_state = RAU_SET_ADDRESS; 4192 sm_run(); 4193 } 4194 4195 #ifdef ENABLE_LE_PERIPHERAL 4196 /* 4197 * @brief Set Advertisement Paramters 4198 * @param adv_int_min 4199 * @param adv_int_max 4200 * @param adv_type 4201 * @param direct_address_type 4202 * @param direct_address 4203 * @param channel_map 4204 * @param filter_policy 4205 * 4206 * @note own_address_type is used from gap_random_address_set_mode 4207 */ 4208 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4209 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4210 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4211 direct_address_typ, direct_address, channel_map, filter_policy); 4212 } 4213 #endif 4214 4215 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4216 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4217 // wrong connection 4218 if (!sm_conn) return 0; 4219 // already encrypted 4220 if (sm_conn->sm_connection_encrypted) return 0; 4221 // only central can re-encrypt 4222 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4223 // irk status? 4224 switch(sm_conn->sm_irk_lookup_state){ 4225 case IRK_LOOKUP_FAILED: 4226 // done, cannot setup encryption 4227 return 0; 4228 case IRK_LOOKUP_SUCCEEDED: 4229 break; 4230 default: 4231 // IR Lookup pending 4232 return 1; 4233 } 4234 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4235 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4236 } 4237