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 uint8_t sm_key_distribution_send_set; 301 uint8_t sm_key_distribution_sent_set; 302 uint8_t sm_key_distribution_received_set; 303 304 // Phase 2 (Pairing over SMP) 305 stk_generation_method_t sm_stk_generation_method; 306 sm_key_t sm_tk; 307 uint8_t sm_have_oob_data; 308 uint8_t sm_use_secure_connections; 309 310 sm_key_t sm_c1_t3_value; // c1 calculation 311 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 312 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 313 sm_key_t sm_local_random; 314 sm_key_t sm_local_confirm; 315 sm_key_t sm_peer_random; 316 sm_key_t sm_peer_confirm; 317 uint8_t sm_m_addr_type; // address and type can be removed 318 uint8_t sm_s_addr_type; // '' 319 bd_addr_t sm_m_address; // '' 320 bd_addr_t sm_s_address; // '' 321 sm_key_t sm_ltk; 322 323 uint8_t sm_state_vars; 324 #ifdef ENABLE_LE_SECURE_CONNECTIONS 325 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 326 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 327 sm_key_t sm_local_nonce; // might be combined with sm_local_random 328 sm_key_t sm_dhkey; 329 sm_key_t sm_peer_dhkey_check; 330 sm_key_t sm_local_dhkey_check; 331 sm_key_t sm_ra; 332 sm_key_t sm_rb; 333 sm_key_t sm_t; // used for f5 and h6 334 sm_key_t sm_mackey; 335 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 336 #endif 337 338 // Phase 3 339 340 // key distribution, we generate 341 uint16_t sm_local_y; 342 uint16_t sm_local_div; 343 uint16_t sm_local_ediv; 344 uint8_t sm_local_rand[8]; 345 sm_key_t sm_local_ltk; 346 sm_key_t sm_local_csrk; 347 sm_key_t sm_local_irk; 348 // sm_local_address/addr_type not needed 349 350 // key distribution, received from peer 351 uint16_t sm_peer_y; 352 uint16_t sm_peer_div; 353 uint16_t sm_peer_ediv; 354 uint8_t sm_peer_rand[8]; 355 sm_key_t sm_peer_ltk; 356 sm_key_t sm_peer_irk; 357 sm_key_t sm_peer_csrk; 358 uint8_t sm_peer_addr_type; 359 bd_addr_t sm_peer_address; 360 #ifdef ENABLE_LE_SIGNED_WRITE 361 int sm_le_device_index; 362 #endif 363 364 } sm_setup_context_t; 365 366 // 367 static sm_setup_context_t the_setup; 368 static sm_setup_context_t * setup = &the_setup; 369 370 // active connection - the one for which the_setup is used for 371 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 372 373 // @returns 1 if oob data is available 374 // stores oob data in provided 16 byte buffer if not null 375 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 376 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); 377 378 // horizontal: initiator capabilities 379 // vertial: responder capabilities 380 static const stk_generation_method_t stk_generation_method [5] [5] = { 381 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 382 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 383 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 384 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 385 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 386 }; 387 388 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 389 #ifdef ENABLE_LE_SECURE_CONNECTIONS 390 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 391 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 392 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 393 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 394 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 395 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 396 }; 397 #endif 398 399 static void sm_run(void); 400 static void sm_done_for_handle(hci_con_handle_t con_handle); 401 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 402 static inline int sm_calc_actual_encryption_key_size(int other); 403 static int sm_validate_stk_generation_method(void); 404 static void sm_handle_encryption_result_address_resolution(void *arg); 405 static void sm_handle_encryption_result_dkg_dhk(void *arg); 406 static void sm_handle_encryption_result_dkg_irk(void *arg); 407 static void sm_handle_encryption_result_enc_a(void *arg); 408 static void sm_handle_encryption_result_enc_b(void *arg); 409 static void sm_handle_encryption_result_enc_c(void *arg); 410 static void sm_handle_encryption_result_enc_csrk(void *arg); 411 static void sm_handle_encryption_result_enc_d(void * arg); 412 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 413 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 414 #ifdef ENABLE_LE_PERIPHERAL 415 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 416 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 417 #endif 418 static void sm_handle_encryption_result_enc_stk(void *arg); 419 static void sm_handle_encryption_result_rau(void *arg); 420 static void sm_handle_random_result_ph2_tk(void * arg); 421 static void sm_handle_random_result_rau(void * arg); 422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 423 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)); 424 static void sm_ec_generate_new_key(void); 425 static void sm_handle_random_result_sc_get_random(void * arg); 426 static int sm_passkey_entry(stk_generation_method_t method); 427 #endif 428 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 429 430 static void log_info_hex16(const char * name, uint16_t value){ 431 log_info("%-6s 0x%04x", name, value); 432 } 433 434 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 435 // return packet[0]; 436 // } 437 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 438 return packet[1]; 439 } 440 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 441 return packet[2]; 442 } 443 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 444 return packet[3]; 445 } 446 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 447 return packet[4]; 448 } 449 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 450 return packet[5]; 451 } 452 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 453 return packet[6]; 454 } 455 456 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 457 packet[0] = code; 458 } 459 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 460 packet[1] = io_capability; 461 } 462 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 463 packet[2] = oob_data_flag; 464 } 465 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 466 packet[3] = auth_req; 467 } 468 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 469 packet[4] = max_encryption_key_size; 470 } 471 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 472 packet[5] = initiator_key_distribution; 473 } 474 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 475 packet[6] = responder_key_distribution; 476 } 477 478 // @returns 1 if all bytes are 0 479 static int sm_is_null(uint8_t * data, int size){ 480 int i; 481 for (i=0; i < size ; i++){ 482 if (data[i]) return 0; 483 } 484 return 1; 485 } 486 487 static int sm_is_null_random(uint8_t random[8]){ 488 return sm_is_null(random, 8); 489 } 490 491 static int sm_is_null_key(uint8_t * key){ 492 return sm_is_null(key, 16); 493 } 494 495 // Key utils 496 static void sm_reset_tk(void){ 497 int i; 498 for (i=0;i<16;i++){ 499 setup->sm_tk[i] = 0; 500 } 501 } 502 503 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 504 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 505 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 506 int i; 507 for (i = max_encryption_size ; i < 16 ; i++){ 508 key[15-i] = 0; 509 } 510 } 511 512 // ER / IR checks 513 static void sm_er_ir_set_default(void){ 514 int i; 515 for (i=0;i<16;i++){ 516 sm_persistent_er[i] = 0x30 + i; 517 sm_persistent_ir[i] = 0x90 + i; 518 } 519 } 520 521 static int sm_er_is_default(void){ 522 int i; 523 for (i=0;i<16;i++){ 524 if (sm_persistent_er[i] != (0x30+i)) return 0; 525 } 526 return 1; 527 } 528 529 static int sm_ir_is_default(void){ 530 int i; 531 for (i=0;i<16;i++){ 532 if (sm_persistent_ir[i] != (0x90+i)) return 0; 533 } 534 return 1; 535 } 536 537 // SMP Timeout implementation 538 539 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 540 // the Security Manager Timer shall be reset and started. 541 // 542 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 543 // 544 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 545 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 546 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 547 // established. 548 549 static void sm_timeout_handler(btstack_timer_source_t * timer){ 550 log_info("SM timeout"); 551 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 552 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 553 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 554 sm_done_for_handle(sm_conn->sm_handle); 555 556 // trigger handling of next ready connection 557 sm_run(); 558 } 559 static void sm_timeout_start(sm_connection_t * sm_conn){ 560 btstack_run_loop_remove_timer(&setup->sm_timeout); 561 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 562 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 563 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 564 btstack_run_loop_add_timer(&setup->sm_timeout); 565 } 566 static void sm_timeout_stop(void){ 567 btstack_run_loop_remove_timer(&setup->sm_timeout); 568 } 569 static void sm_timeout_reset(sm_connection_t * sm_conn){ 570 sm_timeout_stop(); 571 sm_timeout_start(sm_conn); 572 } 573 574 // end of sm timeout 575 576 // GAP Random Address updates 577 static gap_random_address_type_t gap_random_adress_type; 578 static btstack_timer_source_t gap_random_address_update_timer; 579 static uint32_t gap_random_adress_update_period; 580 581 static void gap_random_address_trigger(void){ 582 log_info("gap_random_address_trigger, state %u", rau_state); 583 if (rau_state != RAU_IDLE) return; 584 rau_state = RAU_GET_RANDOM; 585 sm_run(); 586 } 587 588 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 589 UNUSED(timer); 590 591 log_info("GAP Random Address Update due"); 592 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 593 btstack_run_loop_add_timer(&gap_random_address_update_timer); 594 gap_random_address_trigger(); 595 } 596 597 static void gap_random_address_update_start(void){ 598 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 599 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 600 btstack_run_loop_add_timer(&gap_random_address_update_timer); 601 } 602 603 static void gap_random_address_update_stop(void){ 604 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 605 } 606 607 // ah(k,r) helper 608 // r = padding || r 609 // r - 24 bit value 610 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 611 // r'= padding || r 612 memset(r_prime, 0, 16); 613 memcpy(&r_prime[13], r, 3); 614 } 615 616 // d1 helper 617 // d' = padding || r || d 618 // d,r - 16 bit values 619 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 620 // d'= padding || r || d 621 memset(d1_prime, 0, 16); 622 big_endian_store_16(d1_prime, 12, r); 623 big_endian_store_16(d1_prime, 14, d); 624 } 625 626 // dm helper 627 // r’ = padding || r 628 // r - 64 bit value 629 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 630 memset(r_prime, 0, 16); 631 memcpy(&r_prime[8], r, 8); 632 } 633 634 // calculate arguments for first AES128 operation in C1 function 635 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){ 636 637 // p1 = pres || preq || rat’ || iat’ 638 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 639 // cant octet of pres becomes the most significant octet of p1. 640 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 641 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 642 // p1 is 0x05000800000302070710000001010001." 643 644 sm_key_t p1; 645 reverse_56(pres, &p1[0]); 646 reverse_56(preq, &p1[7]); 647 p1[14] = rat; 648 p1[15] = iat; 649 log_info_key("p1", p1); 650 log_info_key("r", r); 651 652 // t1 = r xor p1 653 int i; 654 for (i=0;i<16;i++){ 655 t1[i] = r[i] ^ p1[i]; 656 } 657 log_info_key("t1", t1); 658 } 659 660 // calculate arguments for second AES128 operation in C1 function 661 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 662 // p2 = padding || ia || ra 663 // "The least significant octet of ra becomes the least significant octet of p2 and 664 // the most significant octet of padding becomes the most significant octet of p2. 665 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 666 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 667 668 sm_key_t p2; 669 memset(p2, 0, 16); 670 memcpy(&p2[4], ia, 6); 671 memcpy(&p2[10], ra, 6); 672 log_info_key("p2", p2); 673 674 // c1 = e(k, t2_xor_p2) 675 int i; 676 for (i=0;i<16;i++){ 677 t3[i] = t2[i] ^ p2[i]; 678 } 679 log_info_key("t3", t3); 680 } 681 682 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 683 log_info_key("r1", r1); 684 log_info_key("r2", r2); 685 memcpy(&r_prime[8], &r2[8], 8); 686 memcpy(&r_prime[0], &r1[8], 8); 687 } 688 689 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 690 UNUSED(channel); 691 692 // log event 693 hci_dump_packet(packet_type, 1, packet, size); 694 // dispatch to all event handlers 695 btstack_linked_list_iterator_t it; 696 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 697 while (btstack_linked_list_iterator_has_next(&it)){ 698 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 699 entry->callback(packet_type, 0, packet, size); 700 } 701 } 702 703 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){ 704 event[0] = type; 705 event[1] = event_size - 2; 706 little_endian_store_16(event, 2, con_handle); 707 event[4] = addr_type; 708 reverse_bd_addr(address, &event[5]); 709 } 710 711 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 712 uint8_t event[11]; 713 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 714 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 715 } 716 717 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){ 718 uint8_t event[15]; 719 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 720 little_endian_store_32(event, 11, passkey); 721 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 722 } 723 724 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){ 725 // fetch addr and addr type from db, only called for valid entries 726 bd_addr_t identity_address; 727 int identity_address_type; 728 le_device_db_info(index, &identity_address_type, identity_address, NULL); 729 730 uint8_t event[20]; 731 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 732 event[11] = identity_address_type; 733 reverse_bd_addr(identity_address, &event[12]); 734 little_endian_store_16(event, 18, index); 735 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 736 } 737 738 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){ 739 uint8_t event[12]; 740 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 741 event[11] = status; 742 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 743 } 744 745 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 746 uint8_t event[13]; 747 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 748 event[11] = status; 749 event[12] = reason; 750 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 751 } 752 753 // decide on stk generation based on 754 // - pairing request 755 // - io capabilities 756 // - OOB data availability 757 static void sm_setup_tk(void){ 758 759 // default: just works 760 setup->sm_stk_generation_method = JUST_WORKS; 761 762 #ifdef ENABLE_LE_SECURE_CONNECTIONS 763 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 764 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 765 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 766 #else 767 setup->sm_use_secure_connections = 0; 768 #endif 769 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 770 771 772 // decide if OOB will be used based on SC vs. Legacy and oob flags 773 int use_oob = 0; 774 if (setup->sm_use_secure_connections){ 775 // In LE Secure Connections pairing, the out of band method is used if at least 776 // one device has the peer device's out of band authentication data available. 777 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 778 } else { 779 // In LE legacy pairing, the out of band method is used if both the devices have 780 // the other device's out of band authentication data available. 781 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 782 } 783 if (use_oob){ 784 log_info("SM: have OOB data"); 785 log_info_key("OOB", setup->sm_tk); 786 setup->sm_stk_generation_method = OOB; 787 return; 788 } 789 790 // If both devices have not set the MITM option in the Authentication Requirements 791 // Flags, then the IO capabilities shall be ignored and the Just Works association 792 // model shall be used. 793 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 794 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 795 log_info("SM: MITM not required by both -> JUST WORKS"); 796 return; 797 } 798 799 // Reset TK as it has been setup in sm_init_setup 800 sm_reset_tk(); 801 802 // Also use just works if unknown io capabilites 803 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)){ 804 return; 805 } 806 807 // Otherwise the IO capabilities of the devices shall be used to determine the 808 // pairing method as defined in Table 2.4. 809 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 810 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 811 812 #ifdef ENABLE_LE_SECURE_CONNECTIONS 813 // table not define by default 814 if (setup->sm_use_secure_connections){ 815 generation_method = stk_generation_method_with_secure_connection; 816 } 817 #endif 818 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)]; 819 820 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 821 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); 822 } 823 824 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 825 int flags = 0; 826 if (key_set & SM_KEYDIST_ENC_KEY){ 827 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 828 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 829 } 830 if (key_set & SM_KEYDIST_ID_KEY){ 831 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 832 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 833 } 834 if (key_set & SM_KEYDIST_SIGN){ 835 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 836 } 837 return flags; 838 } 839 840 static void sm_setup_key_distribution(uint8_t key_set){ 841 setup->sm_key_distribution_received_set = 0; 842 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 843 setup->sm_key_distribution_sent_set = 0; 844 #ifdef ENABLE_LE_SIGNED_WRITE 845 setup->sm_le_device_index = -1; 846 #endif 847 } 848 849 // CSRK Key Lookup 850 851 852 static int sm_address_resolution_idle(void){ 853 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 854 } 855 856 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){ 857 memcpy(sm_address_resolution_address, addr, 6); 858 sm_address_resolution_addr_type = addr_type; 859 sm_address_resolution_test = 0; 860 sm_address_resolution_mode = mode; 861 sm_address_resolution_context = context; 862 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 863 } 864 865 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 866 // check if already in list 867 btstack_linked_list_iterator_t it; 868 sm_lookup_entry_t * entry; 869 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 870 while(btstack_linked_list_iterator_has_next(&it)){ 871 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 872 if (entry->address_type != address_type) continue; 873 if (memcmp(entry->address, address, 6)) continue; 874 // already in list 875 return BTSTACK_BUSY; 876 } 877 entry = btstack_memory_sm_lookup_entry_get(); 878 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 879 entry->address_type = (bd_addr_type_t) address_type; 880 memcpy(entry->address, address, 6); 881 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 882 sm_run(); 883 return 0; 884 } 885 886 // CMAC calculation using AES Engineq 887 #ifdef USE_CMAC_ENGINE 888 889 static void sm_cmac_done_trampoline(void * arg){ 890 UNUSED(arg); 891 sm_cmac_active = 0; 892 (*sm_cmac_done_callback)(sm_cmac_hash); 893 sm_run(); 894 } 895 896 int sm_cmac_ready(void){ 897 return sm_cmac_active == 0; 898 } 899 #endif 900 901 #ifdef ENABLE_LE_SECURE_CONNECTIONS 902 // generic cmac calculation 903 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)){ 904 sm_cmac_active = 1; 905 sm_cmac_done_callback = done_callback; 906 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 907 } 908 #endif 909 910 // cmac for ATT Message signing 911 #ifdef ENABLE_LE_SIGNED_WRITE 912 913 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)){ 914 sm_cmac_active = 1; 915 sm_cmac_done_callback = done_callback; 916 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 917 } 918 919 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 920 if (offset >= sm_cmac_signed_write_message_len) { 921 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 922 return 0; 923 } 924 925 offset = sm_cmac_signed_write_message_len - 1 - offset; 926 927 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 928 if (offset < 3){ 929 return sm_cmac_signed_write_header[offset]; 930 } 931 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 932 if (offset < actual_message_len_incl_header){ 933 return sm_cmac_signed_write_message[offset - 3]; 934 } 935 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 936 } 937 938 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)){ 939 // ATT Message Signing 940 sm_cmac_signed_write_header[0] = opcode; 941 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 942 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 943 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 944 sm_cmac_signed_write_message = message; 945 sm_cmac_signed_write_message_len = total_message_len; 946 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 947 } 948 #endif 949 950 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 951 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 952 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 953 switch (setup->sm_stk_generation_method){ 954 case PK_RESP_INPUT: 955 if (IS_RESPONDER(sm_conn->sm_role)){ 956 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 957 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 958 } else { 959 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)); 960 } 961 break; 962 case PK_INIT_INPUT: 963 if (IS_RESPONDER(sm_conn->sm_role)){ 964 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)); 965 } else { 966 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 967 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 968 } 969 break; 970 case PK_BOTH_INPUT: 971 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 972 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 973 break; 974 case NUMERIC_COMPARISON: 975 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 976 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)); 977 break; 978 case JUST_WORKS: 979 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 980 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 981 break; 982 case OOB: 983 // client already provided OOB data, let's skip notification. 984 break; 985 } 986 } 987 988 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 989 int recv_flags; 990 if (IS_RESPONDER(sm_conn->sm_role)){ 991 // slave / responder 992 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 993 } else { 994 // master / initiator 995 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 996 } 997 998 #ifdef ENABLE_LE_SECURE_CONNECTIONS 999 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1000 if (setup->sm_use_secure_connections){ 1001 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1002 } 1003 #endif 1004 1005 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1006 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1007 } 1008 1009 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1010 if (sm_active_connection_handle == con_handle){ 1011 sm_timeout_stop(); 1012 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1013 log_info("sm: connection 0x%x released setup context", con_handle); 1014 1015 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1016 // generate new ec key after each pairing (that used it) 1017 if (setup->sm_use_secure_connections){ 1018 sm_ec_generate_new_key(); 1019 } 1020 #endif 1021 } 1022 } 1023 1024 static int sm_key_distribution_flags_for_auth_req(void){ 1025 1026 int flags = SM_KEYDIST_ID_KEY; 1027 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1028 // encryption and signing information only if bonding requested 1029 flags |= SM_KEYDIST_ENC_KEY; 1030 #ifdef ENABLE_LE_SIGNED_WRITE 1031 flags |= SM_KEYDIST_SIGN; 1032 #endif 1033 } 1034 return flags; 1035 } 1036 1037 static void sm_reset_setup(void){ 1038 // fill in sm setup 1039 setup->sm_state_vars = 0; 1040 setup->sm_keypress_notification = 0; 1041 sm_reset_tk(); 1042 } 1043 1044 static void sm_init_setup(sm_connection_t * sm_conn){ 1045 1046 // fill in sm setup 1047 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1048 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1049 1050 // query client for Legacy Pairing OOB data 1051 setup->sm_have_oob_data = 0; 1052 if (sm_get_oob_data) { 1053 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1054 } 1055 1056 // if available and SC supported, also ask for SC OOB Data 1057 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1058 memset(setup->sm_ra, 0, 16); 1059 memset(setup->sm_rb, 0, 16); 1060 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1061 if (sm_get_sc_oob_data){ 1062 if (IS_RESPONDER(sm_conn->sm_role)){ 1063 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1064 sm_conn->sm_peer_addr_type, 1065 sm_conn->sm_peer_address, 1066 setup->sm_peer_confirm, 1067 setup->sm_ra); 1068 } else { 1069 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1070 sm_conn->sm_peer_addr_type, 1071 sm_conn->sm_peer_address, 1072 setup->sm_peer_confirm, 1073 setup->sm_rb); 1074 } 1075 } else { 1076 setup->sm_have_oob_data = 0; 1077 } 1078 } 1079 #endif 1080 1081 sm_pairing_packet_t * local_packet; 1082 if (IS_RESPONDER(sm_conn->sm_role)){ 1083 // slave 1084 local_packet = &setup->sm_s_pres; 1085 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1086 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1087 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1088 } else { 1089 // master 1090 local_packet = &setup->sm_m_preq; 1091 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1092 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1093 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1094 1095 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1096 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1097 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1098 } 1099 1100 uint8_t auth_req = sm_auth_req; 1101 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1102 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1103 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1104 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1105 } 1106 1107 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1108 1109 sm_pairing_packet_t * remote_packet; 1110 int remote_key_request; 1111 if (IS_RESPONDER(sm_conn->sm_role)){ 1112 // slave / responder 1113 remote_packet = &setup->sm_m_preq; 1114 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1115 } else { 1116 // master / initiator 1117 remote_packet = &setup->sm_s_pres; 1118 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1119 } 1120 1121 // check key size 1122 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1123 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1124 1125 // decide on STK generation method / SC 1126 sm_setup_tk(); 1127 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1128 1129 // check if STK generation method is acceptable by client 1130 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1131 1132 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1133 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1134 if (setup->sm_use_secure_connections){ 1135 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1136 } 1137 #endif 1138 1139 // identical to responder 1140 sm_setup_key_distribution(remote_key_request); 1141 1142 // JUST WORKS doens't provide authentication 1143 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1144 1145 return 0; 1146 } 1147 1148 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1149 1150 // cache and reset context 1151 int matched_device_id = sm_address_resolution_test; 1152 address_resolution_mode_t mode = sm_address_resolution_mode; 1153 void * context = sm_address_resolution_context; 1154 1155 // reset context 1156 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1157 sm_address_resolution_context = NULL; 1158 sm_address_resolution_test = -1; 1159 hci_con_handle_t con_handle = 0; 1160 1161 sm_connection_t * sm_connection; 1162 #ifdef ENABLE_LE_CENTRAL 1163 sm_key_t ltk; 1164 int have_ltk; 1165 int pairing_need; 1166 #endif 1167 switch (mode){ 1168 case ADDRESS_RESOLUTION_GENERAL: 1169 break; 1170 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1171 sm_connection = (sm_connection_t *) context; 1172 con_handle = sm_connection->sm_handle; 1173 switch (event){ 1174 case ADDRESS_RESOLUTION_SUCEEDED: 1175 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1176 sm_connection->sm_le_db_index = matched_device_id; 1177 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1178 if (sm_connection->sm_role) { 1179 // LTK request received before, IRK required -> start LTK calculation 1180 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1181 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1182 } 1183 break; 1184 } 1185 #ifdef ENABLE_LE_CENTRAL 1186 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1187 have_ltk = !sm_is_null_key(ltk); 1188 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1189 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1190 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1191 // reset requests 1192 sm_connection->sm_security_request_received = 0; 1193 sm_connection->sm_pairing_requested = 0; 1194 1195 // have ltk -> start encryption 1196 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1197 // "When a bond has been created between two devices, any reconnection should result in the local device 1198 // enabling or requesting encryption with the remote device before initiating any service request." 1199 if (have_ltk){ 1200 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1202 break; 1203 #else 1204 log_info("central: defer enabling encryption for bonded device"); 1205 #endif 1206 } 1207 // pairint_request -> send pairing request 1208 if (pairing_need){ 1209 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1210 break; 1211 } 1212 #endif 1213 break; 1214 case ADDRESS_RESOLUTION_FAILED: 1215 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1216 if (sm_connection->sm_role) { 1217 // LTK request received before, IRK required -> negative LTK reply 1218 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1219 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1220 } 1221 break; 1222 } 1223 #ifdef ENABLE_LE_CENTRAL 1224 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1225 sm_connection->sm_security_request_received = 0; 1226 sm_connection->sm_pairing_requested = 0; 1227 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1228 #endif 1229 break; 1230 } 1231 break; 1232 default: 1233 break; 1234 } 1235 1236 switch (event){ 1237 case ADDRESS_RESOLUTION_SUCEEDED: 1238 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1239 break; 1240 case ADDRESS_RESOLUTION_FAILED: 1241 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1242 break; 1243 } 1244 } 1245 1246 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1247 1248 int le_db_index = -1; 1249 1250 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1251 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1252 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1253 & SM_AUTHREQ_BONDING ) != 0; 1254 1255 if (bonding_enabed){ 1256 1257 // lookup device based on IRK 1258 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1259 int i; 1260 for (i=0; i < le_device_db_max_count(); i++){ 1261 sm_key_t irk; 1262 bd_addr_t address; 1263 int address_type = BD_ADDR_TYPE_UNKNOWN; 1264 le_device_db_info(i, &address_type, address, irk); 1265 // skip unused entries 1266 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1267 // compare IRK 1268 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1269 1270 log_info("sm: device found for IRK, updating"); 1271 le_db_index = i; 1272 break; 1273 } 1274 } else { 1275 // assert IRK is set to zero 1276 memset(setup->sm_peer_irk, 0, 16); 1277 } 1278 1279 // if not found, lookup via public address if possible 1280 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1281 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1282 int i; 1283 for (i=0; i < le_device_db_max_count(); i++){ 1284 bd_addr_t address; 1285 int address_type = BD_ADDR_TYPE_UNKNOWN; 1286 le_device_db_info(i, &address_type, address, NULL); 1287 // skip unused entries 1288 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1289 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1290 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1291 log_info("sm: device found for public address, updating"); 1292 le_db_index = i; 1293 break; 1294 } 1295 } 1296 } 1297 1298 // if not found, add to db 1299 if (le_db_index < 0) { 1300 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1301 } 1302 1303 if (le_db_index >= 0){ 1304 1305 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1306 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1307 1308 #ifdef ENABLE_LE_SIGNED_WRITE 1309 // store local CSRK 1310 setup->sm_le_device_index = le_db_index; 1311 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1312 log_info("sm: store local CSRK"); 1313 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1314 le_device_db_local_counter_set(le_db_index, 0); 1315 } 1316 1317 // store remote CSRK 1318 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1319 log_info("sm: store remote CSRK"); 1320 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1321 le_device_db_remote_counter_set(le_db_index, 0); 1322 } 1323 #endif 1324 // store encryption information for secure connections: LTK generated by ECDH 1325 if (setup->sm_use_secure_connections){ 1326 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1327 uint8_t zero_rand[8]; 1328 memset(zero_rand, 0, 8); 1329 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1330 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1331 } 1332 1333 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1334 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1335 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1336 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1337 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1338 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1339 1340 } 1341 } 1342 } else { 1343 log_info("Ignoring received keys, bonding not enabled"); 1344 } 1345 1346 // keep le_db_index 1347 sm_conn->sm_le_db_index = le_db_index; 1348 } 1349 1350 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1351 setup->sm_pairing_failed_reason = reason; 1352 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1353 } 1354 1355 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1356 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1357 } 1358 1359 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1360 1361 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1362 static int sm_passkey_used(stk_generation_method_t method); 1363 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1364 1365 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1366 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1367 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1368 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1369 } else { 1370 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1371 } 1372 } 1373 1374 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1375 if (IS_RESPONDER(sm_conn->sm_role)){ 1376 // Responder 1377 if (setup->sm_stk_generation_method == OOB){ 1378 // generate Nb 1379 log_info("Generate Nb"); 1380 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1381 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1382 } else { 1383 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1384 } 1385 } else { 1386 // Initiator role 1387 switch (setup->sm_stk_generation_method){ 1388 case JUST_WORKS: 1389 sm_sc_prepare_dhkey_check(sm_conn); 1390 break; 1391 1392 case NUMERIC_COMPARISON: 1393 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1394 break; 1395 case PK_INIT_INPUT: 1396 case PK_RESP_INPUT: 1397 case PK_BOTH_INPUT: 1398 if (setup->sm_passkey_bit < 20) { 1399 sm_sc_start_calculating_local_confirm(sm_conn); 1400 } else { 1401 sm_sc_prepare_dhkey_check(sm_conn); 1402 } 1403 break; 1404 case OOB: 1405 sm_sc_prepare_dhkey_check(sm_conn); 1406 break; 1407 } 1408 } 1409 } 1410 1411 static void sm_sc_cmac_done(uint8_t * hash){ 1412 log_info("sm_sc_cmac_done: "); 1413 log_info_hexdump(hash, 16); 1414 1415 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1416 sm_sc_oob_state = SM_SC_OOB_IDLE; 1417 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1418 return; 1419 } 1420 1421 sm_connection_t * sm_conn = sm_cmac_connection; 1422 sm_cmac_connection = NULL; 1423 #ifdef ENABLE_CLASSIC 1424 link_key_type_t link_key_type; 1425 #endif 1426 1427 switch (sm_conn->sm_engine_state){ 1428 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1429 memcpy(setup->sm_local_confirm, hash, 16); 1430 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1431 break; 1432 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1433 // check 1434 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1435 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1436 break; 1437 } 1438 sm_sc_state_after_receiving_random(sm_conn); 1439 break; 1440 case SM_SC_W4_CALCULATE_G2: { 1441 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1442 big_endian_store_32(setup->sm_tk, 12, vab); 1443 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1444 sm_trigger_user_response(sm_conn); 1445 break; 1446 } 1447 case SM_SC_W4_CALCULATE_F5_SALT: 1448 memcpy(setup->sm_t, hash, 16); 1449 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1450 break; 1451 case SM_SC_W4_CALCULATE_F5_MACKEY: 1452 memcpy(setup->sm_mackey, hash, 16); 1453 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1454 break; 1455 case SM_SC_W4_CALCULATE_F5_LTK: 1456 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1457 // Errata Service Release to the Bluetooth Specification: ESR09 1458 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1459 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1460 memcpy(setup->sm_ltk, hash, 16); 1461 memcpy(setup->sm_local_ltk, hash, 16); 1462 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1463 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1464 break; 1465 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1466 memcpy(setup->sm_local_dhkey_check, hash, 16); 1467 if (IS_RESPONDER(sm_conn->sm_role)){ 1468 // responder 1469 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1470 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1471 } else { 1472 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1473 } 1474 } else { 1475 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1476 } 1477 break; 1478 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1479 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1480 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1481 break; 1482 } 1483 if (IS_RESPONDER(sm_conn->sm_role)){ 1484 // responder 1485 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1486 } else { 1487 // initiator 1488 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1489 } 1490 break; 1491 case SM_SC_W4_CALCULATE_H6_ILK: 1492 memcpy(setup->sm_t, hash, 16); 1493 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1494 break; 1495 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1496 #ifdef ENABLE_CLASSIC 1497 reverse_128(hash, setup->sm_t); 1498 link_key_type = sm_conn->sm_connection_authenticated ? 1499 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1500 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1501 if (IS_RESPONDER(sm_conn->sm_role)){ 1502 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1503 } else { 1504 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1505 } 1506 #endif 1507 if (IS_RESPONDER(sm_conn->sm_role)){ 1508 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1509 } else { 1510 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1511 } 1512 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1513 sm_done_for_handle(sm_conn->sm_handle); 1514 break; 1515 default: 1516 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1517 break; 1518 } 1519 sm_run(); 1520 } 1521 1522 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){ 1523 const uint16_t message_len = 65; 1524 sm_cmac_connection = sm_conn; 1525 memcpy(sm_cmac_sc_buffer, u, 32); 1526 memcpy(sm_cmac_sc_buffer+32, v, 32); 1527 sm_cmac_sc_buffer[64] = z; 1528 log_info("f4 key"); 1529 log_info_hexdump(x, 16); 1530 log_info("f4 message"); 1531 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1532 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1533 } 1534 1535 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1536 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1537 static const uint8_t f5_length[] = { 0x01, 0x00}; 1538 1539 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1540 log_info("f5_calculate_salt"); 1541 // calculate salt for f5 1542 const uint16_t message_len = 32; 1543 sm_cmac_connection = sm_conn; 1544 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1545 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1546 } 1547 1548 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){ 1549 const uint16_t message_len = 53; 1550 sm_cmac_connection = sm_conn; 1551 1552 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1553 sm_cmac_sc_buffer[0] = 0; 1554 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1555 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1556 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1557 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1558 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1559 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1560 log_info("f5 key"); 1561 log_info_hexdump(t, 16); 1562 log_info("f5 message for MacKey"); 1563 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1564 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1565 } 1566 1567 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1568 sm_key56_t bd_addr_master, bd_addr_slave; 1569 bd_addr_master[0] = setup->sm_m_addr_type; 1570 bd_addr_slave[0] = setup->sm_s_addr_type; 1571 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1572 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1573 if (IS_RESPONDER(sm_conn->sm_role)){ 1574 // responder 1575 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1576 } else { 1577 // initiator 1578 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1579 } 1580 } 1581 1582 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1583 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1584 const uint16_t message_len = 53; 1585 sm_cmac_connection = sm_conn; 1586 sm_cmac_sc_buffer[0] = 1; 1587 // 1..52 setup before 1588 log_info("f5 key"); 1589 log_info_hexdump(t, 16); 1590 log_info("f5 message for LTK"); 1591 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1592 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1593 } 1594 1595 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1596 f5_ltk(sm_conn, setup->sm_t); 1597 } 1598 1599 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){ 1600 const uint16_t message_len = 65; 1601 sm_cmac_connection = sm_conn; 1602 memcpy(sm_cmac_sc_buffer, n1, 16); 1603 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1604 memcpy(sm_cmac_sc_buffer+32, r, 16); 1605 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1606 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1607 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1608 log_info("f6 key"); 1609 log_info_hexdump(w, 16); 1610 log_info("f6 message"); 1611 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1612 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1613 } 1614 1615 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1616 // - U is 256 bits 1617 // - V is 256 bits 1618 // - X is 128 bits 1619 // - Y is 128 bits 1620 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){ 1621 const uint16_t message_len = 80; 1622 sm_cmac_connection = sm_conn; 1623 memcpy(sm_cmac_sc_buffer, u, 32); 1624 memcpy(sm_cmac_sc_buffer+32, v, 32); 1625 memcpy(sm_cmac_sc_buffer+64, y, 16); 1626 log_info("g2 key"); 1627 log_info_hexdump(x, 16); 1628 log_info("g2 message"); 1629 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1630 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1631 } 1632 1633 static void g2_calculate(sm_connection_t * sm_conn) { 1634 // calc Va if numeric comparison 1635 if (IS_RESPONDER(sm_conn->sm_role)){ 1636 // responder 1637 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1638 } else { 1639 // initiator 1640 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1641 } 1642 } 1643 1644 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1645 uint8_t z = 0; 1646 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1647 // some form of passkey 1648 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1649 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1650 setup->sm_passkey_bit++; 1651 } 1652 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1653 } 1654 1655 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1656 // OOB 1657 if (setup->sm_stk_generation_method == OOB){ 1658 if (IS_RESPONDER(sm_conn->sm_role)){ 1659 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1660 } else { 1661 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1662 } 1663 return; 1664 } 1665 1666 uint8_t z = 0; 1667 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1668 // some form of passkey 1669 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1670 // sm_passkey_bit was increased before sending confirm value 1671 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1672 } 1673 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1674 } 1675 1676 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1677 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1678 1679 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1680 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1681 return; 1682 } else { 1683 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1684 } 1685 } 1686 1687 static void sm_sc_dhkey_calculated(void * arg){ 1688 sm_connection_t * sm_conn = (sm_connection_t *) arg; 1689 log_info("dhkey"); 1690 log_info_hexdump(&setup->sm_dhkey[0], 32); 1691 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1692 // trigger next step 1693 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1694 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1695 } 1696 sm_run(); 1697 } 1698 1699 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1700 // calculate DHKCheck 1701 sm_key56_t bd_addr_master, bd_addr_slave; 1702 bd_addr_master[0] = setup->sm_m_addr_type; 1703 bd_addr_slave[0] = setup->sm_s_addr_type; 1704 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1705 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1706 uint8_t iocap_a[3]; 1707 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1708 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1709 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1710 uint8_t iocap_b[3]; 1711 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1712 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1713 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1714 if (IS_RESPONDER(sm_conn->sm_role)){ 1715 // responder 1716 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); 1717 } else { 1718 // initiator 1719 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); 1720 } 1721 } 1722 1723 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1724 // validate E = f6() 1725 sm_key56_t bd_addr_master, bd_addr_slave; 1726 bd_addr_master[0] = setup->sm_m_addr_type; 1727 bd_addr_slave[0] = setup->sm_s_addr_type; 1728 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1729 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1730 1731 uint8_t iocap_a[3]; 1732 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1733 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1734 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1735 uint8_t iocap_b[3]; 1736 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1737 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1738 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1739 if (IS_RESPONDER(sm_conn->sm_role)){ 1740 // responder 1741 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); 1742 } else { 1743 // initiator 1744 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); 1745 } 1746 } 1747 1748 1749 // 1750 // Link Key Conversion Function h6 1751 // 1752 // h6(W, keyID) = AES-CMACW(keyID) 1753 // - W is 128 bits 1754 // - keyID is 32 bits 1755 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1756 const uint16_t message_len = 4; 1757 sm_cmac_connection = sm_conn; 1758 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1759 log_info("h6 key"); 1760 log_info_hexdump(w, 16); 1761 log_info("h6 message"); 1762 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1763 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1764 } 1765 1766 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1767 // Errata Service Release to the Bluetooth Specification: ESR09 1768 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1769 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1770 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1771 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1772 } 1773 1774 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1775 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1776 } 1777 1778 #endif 1779 1780 // key management legacy connections: 1781 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1782 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1783 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1784 // - responder reconnects: responder uses LTK receveived from master 1785 1786 // key management secure connections: 1787 // - both devices store same LTK from ECDH key exchange. 1788 1789 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1790 static void sm_load_security_info(sm_connection_t * sm_connection){ 1791 int encryption_key_size; 1792 int authenticated; 1793 int authorized; 1794 int secure_connection; 1795 1796 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1797 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1798 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1799 log_info("db index %u, key size %u, authenticated %u, authorized %u, secure connetion %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized, secure_connection); 1800 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1801 sm_connection->sm_connection_authenticated = authenticated; 1802 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1803 sm_connection->sm_connection_sc = secure_connection; 1804 } 1805 #endif 1806 1807 #ifdef ENABLE_LE_PERIPHERAL 1808 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1809 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1810 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1811 // re-establish used key encryption size 1812 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1813 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1814 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1815 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1816 // Legacy paring -> not SC 1817 sm_connection->sm_connection_sc = 0; 1818 log_info("sm: received ltk request with key size %u, authenticated %u", 1819 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1820 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1821 sm_run(); 1822 } 1823 #endif 1824 1825 static void sm_run(void){ 1826 1827 btstack_linked_list_iterator_t it; 1828 1829 // assert that stack has already bootet 1830 if (hci_get_state() != HCI_STATE_WORKING) return; 1831 1832 // assert that we can send at least commands 1833 if (!hci_can_send_command_packet_now()) return; 1834 1835 // pause until IR/ER are ready 1836 if (sm_persistent_keys_random_active) return; 1837 1838 // 1839 // non-connection related behaviour 1840 // 1841 1842 // distributed key generation 1843 switch (dkg_state){ 1844 case DKG_CALC_IRK: 1845 // already busy? 1846 if (sm_aes128_state == SM_AES128_IDLE) { 1847 log_info("DKG_CALC_IRK started"); 1848 // IRK = d1(IR, 1, 0) 1849 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1850 sm_aes128_state = SM_AES128_ACTIVE; 1851 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1852 return; 1853 } 1854 break; 1855 case DKG_CALC_DHK: 1856 // already busy? 1857 if (sm_aes128_state == SM_AES128_IDLE) { 1858 log_info("DKG_CALC_DHK started"); 1859 // DHK = d1(IR, 3, 0) 1860 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1861 sm_aes128_state = SM_AES128_ACTIVE; 1862 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1863 return; 1864 } 1865 break; 1866 default: 1867 break; 1868 } 1869 1870 // random address updates 1871 switch (rau_state){ 1872 case RAU_GET_RANDOM: 1873 rau_state = RAU_W4_RANDOM; 1874 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1875 return; 1876 case RAU_GET_ENC: 1877 // already busy? 1878 if (sm_aes128_state == SM_AES128_IDLE) { 1879 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1880 sm_aes128_state = SM_AES128_ACTIVE; 1881 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1882 return; 1883 } 1884 break; 1885 case RAU_SET_ADDRESS: 1886 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1887 rau_state = RAU_IDLE; 1888 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1889 return; 1890 default: 1891 break; 1892 } 1893 1894 // CSRK Lookup 1895 // -- if csrk lookup ready, find connection that require csrk lookup 1896 if (sm_address_resolution_idle()){ 1897 hci_connections_get_iterator(&it); 1898 while(btstack_linked_list_iterator_has_next(&it)){ 1899 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1900 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1901 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1902 // and start lookup 1903 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); 1904 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1905 break; 1906 } 1907 } 1908 } 1909 1910 // -- if csrk lookup ready, resolved addresses for received addresses 1911 if (sm_address_resolution_idle()) { 1912 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1913 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1914 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1915 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1916 btstack_memory_sm_lookup_entry_free(entry); 1917 } 1918 } 1919 1920 // -- Continue with CSRK device lookup by public or resolvable private address 1921 if (!sm_address_resolution_idle()){ 1922 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1923 while (sm_address_resolution_test < le_device_db_max_count()){ 1924 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1925 bd_addr_t addr; 1926 sm_key_t irk; 1927 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1928 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1929 1930 // skip unused entries 1931 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1932 sm_address_resolution_test++; 1933 continue; 1934 } 1935 1936 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1937 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1938 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1939 break; 1940 } 1941 1942 // if connection type is public, it must be a different one 1943 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1944 sm_address_resolution_test++; 1945 continue; 1946 } 1947 1948 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1949 1950 log_info("LE Device Lookup: calculate AH"); 1951 log_info_key("IRK", irk); 1952 1953 memcpy(sm_aes128_key, irk, 16); 1954 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1955 sm_address_resolution_ah_calculation_active = 1; 1956 sm_aes128_state = SM_AES128_ACTIVE; 1957 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1958 return; 1959 } 1960 1961 if (sm_address_resolution_test >= le_device_db_max_count()){ 1962 log_info("LE Device Lookup: not found"); 1963 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1964 } 1965 } 1966 1967 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1968 switch (sm_sc_oob_state){ 1969 case SM_SC_OOB_W2_CALC_CONFIRM: 1970 if (!sm_cmac_ready()) break; 1971 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1972 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1973 return; 1974 default: 1975 break; 1976 } 1977 #endif 1978 1979 // assert that we can send at least commands - cmd might have been sent by crypto engine 1980 if (!hci_can_send_command_packet_now()) return; 1981 1982 // handle basic actions that don't requires the full context 1983 hci_connections_get_iterator(&it); 1984 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1985 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1986 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1987 switch(sm_connection->sm_engine_state){ 1988 // responder side 1989 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1990 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1991 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1992 return; 1993 1994 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1995 case SM_SC_RECEIVED_LTK_REQUEST: 1996 switch (sm_connection->sm_irk_lookup_state){ 1997 case IRK_LOOKUP_FAILED: 1998 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1999 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2000 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2001 return; 2002 default: 2003 break; 2004 } 2005 break; 2006 #endif 2007 default: 2008 break; 2009 } 2010 } 2011 2012 // 2013 // active connection handling 2014 // -- use loop to handle next connection if lock on setup context is released 2015 2016 while (1) { 2017 2018 // Find connections that requires setup context and make active if no other is locked 2019 hci_connections_get_iterator(&it); 2020 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2021 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2022 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2023 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2024 int done = 1; 2025 int err; 2026 UNUSED(err); 2027 2028 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2029 // assert ec key is ready 2030 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2031 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2032 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2033 sm_ec_generate_new_key(); 2034 } 2035 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2036 continue; 2037 } 2038 } 2039 #endif 2040 2041 switch (sm_connection->sm_engine_state) { 2042 #ifdef ENABLE_LE_PERIPHERAL 2043 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2044 // send packet if possible, 2045 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2046 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2047 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2048 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2049 } else { 2050 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2051 } 2052 // don't lock sxetup context yet 2053 done = 0; 2054 break; 2055 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2056 sm_reset_setup(); 2057 sm_init_setup(sm_connection); 2058 // recover pairing request 2059 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2060 err = sm_stk_generation_init(sm_connection); 2061 2062 #ifdef ENABLE_TESTING_SUPPORT 2063 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2064 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2065 err = test_pairing_failure; 2066 } 2067 #endif 2068 if (err){ 2069 setup->sm_pairing_failed_reason = err; 2070 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2071 break; 2072 } 2073 sm_timeout_start(sm_connection); 2074 // generate random number first, if we need to show passkey 2075 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2076 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2077 break; 2078 } 2079 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2080 break; 2081 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2082 sm_reset_setup(); 2083 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2084 break; 2085 2086 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2087 case SM_SC_RECEIVED_LTK_REQUEST: 2088 switch (sm_connection->sm_irk_lookup_state){ 2089 case IRK_LOOKUP_SUCCEEDED: 2090 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2091 // start using context by loading security info 2092 sm_reset_setup(); 2093 sm_load_security_info(sm_connection); 2094 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2095 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2096 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2097 break; 2098 } 2099 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2100 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2101 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2102 // don't lock setup context yet 2103 return; 2104 default: 2105 // just wait until IRK lookup is completed 2106 // don't lock setup context yet 2107 done = 0; 2108 break; 2109 } 2110 break; 2111 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2112 #endif /* ENABLE_LE_PERIPHERAL */ 2113 2114 #ifdef ENABLE_LE_CENTRAL 2115 case SM_INITIATOR_PH0_HAS_LTK: 2116 sm_reset_setup(); 2117 sm_load_security_info(sm_connection); 2118 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2119 break; 2120 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2121 sm_reset_setup(); 2122 sm_init_setup(sm_connection); 2123 sm_timeout_start(sm_connection); 2124 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2125 break; 2126 #endif 2127 2128 default: 2129 done = 0; 2130 break; 2131 } 2132 if (done){ 2133 sm_active_connection_handle = sm_connection->sm_handle; 2134 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); 2135 } 2136 } 2137 2138 // 2139 // active connection handling 2140 // 2141 2142 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2143 2144 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2145 if (!connection) { 2146 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2147 return; 2148 } 2149 2150 // assert that we could send a SM PDU - not needed for all of the following 2151 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2152 log_info("cannot send now, requesting can send now event"); 2153 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2154 return; 2155 } 2156 2157 // send keypress notifications 2158 if (setup->sm_keypress_notification){ 2159 int i; 2160 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2161 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2162 uint8_t action = 0; 2163 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2164 if (flags & (1<<i)){ 2165 int clear_flag = 1; 2166 switch (i){ 2167 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2168 case SM_KEYPRESS_PASSKEY_CLEARED: 2169 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2170 default: 2171 break; 2172 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2173 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2174 num_actions--; 2175 clear_flag = num_actions == 0; 2176 break; 2177 } 2178 if (clear_flag){ 2179 flags &= ~(1<<i); 2180 } 2181 action = i; 2182 break; 2183 } 2184 } 2185 setup->sm_keypress_notification = (num_actions << 5) | flags; 2186 2187 // send keypress notification 2188 uint8_t buffer[2]; 2189 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2190 buffer[1] = action; 2191 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2192 2193 // try 2194 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2195 return; 2196 } 2197 2198 int key_distribution_flags; 2199 UNUSED(key_distribution_flags); 2200 2201 log_info("sm_run: state %u", connection->sm_engine_state); 2202 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2203 log_info("sm_run // cannot send"); 2204 } 2205 switch (connection->sm_engine_state){ 2206 2207 // general 2208 case SM_GENERAL_SEND_PAIRING_FAILED: { 2209 uint8_t buffer[2]; 2210 buffer[0] = SM_CODE_PAIRING_FAILED; 2211 buffer[1] = setup->sm_pairing_failed_reason; 2212 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2213 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2214 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2215 sm_done_for_handle(connection->sm_handle); 2216 break; 2217 } 2218 2219 // responding state 2220 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2221 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2222 if (!sm_cmac_ready()) break; 2223 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2224 sm_sc_calculate_local_confirm(connection); 2225 break; 2226 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2227 if (!sm_cmac_ready()) break; 2228 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2229 sm_sc_calculate_remote_confirm(connection); 2230 break; 2231 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2232 if (!sm_cmac_ready()) break; 2233 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2234 sm_sc_calculate_f6_for_dhkey_check(connection); 2235 break; 2236 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2237 if (!sm_cmac_ready()) break; 2238 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2239 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2240 break; 2241 case SM_SC_W2_CALCULATE_F5_SALT: 2242 if (!sm_cmac_ready()) break; 2243 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2244 f5_calculate_salt(connection); 2245 break; 2246 case SM_SC_W2_CALCULATE_F5_MACKEY: 2247 if (!sm_cmac_ready()) break; 2248 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2249 f5_calculate_mackey(connection); 2250 break; 2251 case SM_SC_W2_CALCULATE_F5_LTK: 2252 if (!sm_cmac_ready()) break; 2253 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2254 f5_calculate_ltk(connection); 2255 break; 2256 case SM_SC_W2_CALCULATE_G2: 2257 if (!sm_cmac_ready()) break; 2258 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2259 g2_calculate(connection); 2260 break; 2261 case SM_SC_W2_CALCULATE_H6_ILK: 2262 if (!sm_cmac_ready()) break; 2263 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2264 h6_calculate_ilk(connection); 2265 break; 2266 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2267 if (!sm_cmac_ready()) break; 2268 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2269 h6_calculate_br_edr_link_key(connection); 2270 break; 2271 #endif 2272 2273 #ifdef ENABLE_LE_CENTRAL 2274 // initiator side 2275 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2276 sm_key_t peer_ltk_flipped; 2277 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2278 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2279 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2280 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2281 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2282 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2283 return; 2284 } 2285 2286 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2287 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2288 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2289 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2290 sm_timeout_reset(connection); 2291 break; 2292 #endif 2293 2294 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2295 2296 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2297 int trigger_user_response = 0; 2298 2299 uint8_t buffer[65]; 2300 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2301 // 2302 reverse_256(&ec_q[0], &buffer[1]); 2303 reverse_256(&ec_q[32], &buffer[33]); 2304 2305 #ifdef ENABLE_TESTING_SUPPORT 2306 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2307 log_info("testing_support: invalidating public key"); 2308 // flip single bit of public key coordinate 2309 buffer[1] ^= 1; 2310 } 2311 #endif 2312 2313 // stk generation method 2314 // passkey entry: notify app to show passkey or to request passkey 2315 switch (setup->sm_stk_generation_method){ 2316 case JUST_WORKS: 2317 case NUMERIC_COMPARISON: 2318 if (IS_RESPONDER(connection->sm_role)){ 2319 // responder 2320 sm_sc_start_calculating_local_confirm(connection); 2321 } else { 2322 // initiator 2323 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2324 } 2325 break; 2326 case PK_INIT_INPUT: 2327 case PK_RESP_INPUT: 2328 case PK_BOTH_INPUT: 2329 // use random TK for display 2330 memcpy(setup->sm_ra, setup->sm_tk, 16); 2331 memcpy(setup->sm_rb, setup->sm_tk, 16); 2332 setup->sm_passkey_bit = 0; 2333 2334 if (IS_RESPONDER(connection->sm_role)){ 2335 // responder 2336 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2337 } else { 2338 // initiator 2339 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2340 } 2341 trigger_user_response = 1; 2342 break; 2343 case OOB: 2344 if (IS_RESPONDER(connection->sm_role)){ 2345 // responder 2346 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2347 } else { 2348 // initiator 2349 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2350 } 2351 break; 2352 } 2353 2354 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2355 sm_timeout_reset(connection); 2356 2357 // trigger user response after sending pdu 2358 if (trigger_user_response){ 2359 sm_trigger_user_response(connection); 2360 } 2361 break; 2362 } 2363 case SM_SC_SEND_CONFIRMATION: { 2364 uint8_t buffer[17]; 2365 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2366 reverse_128(setup->sm_local_confirm, &buffer[1]); 2367 if (IS_RESPONDER(connection->sm_role)){ 2368 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2369 } else { 2370 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2371 } 2372 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2373 sm_timeout_reset(connection); 2374 break; 2375 } 2376 case SM_SC_SEND_PAIRING_RANDOM: { 2377 uint8_t buffer[17]; 2378 buffer[0] = SM_CODE_PAIRING_RANDOM; 2379 reverse_128(setup->sm_local_nonce, &buffer[1]); 2380 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2381 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2382 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2383 if (IS_RESPONDER(connection->sm_role)){ 2384 // responder 2385 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2386 } else { 2387 // initiator 2388 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2389 } 2390 } else { 2391 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2392 if (IS_RESPONDER(connection->sm_role)){ 2393 // responder 2394 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2395 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2396 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2397 } else { 2398 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2399 sm_sc_prepare_dhkey_check(connection); 2400 } 2401 } else { 2402 // initiator 2403 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2404 } 2405 } 2406 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2407 sm_timeout_reset(connection); 2408 break; 2409 } 2410 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2411 uint8_t buffer[17]; 2412 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2413 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2414 2415 if (IS_RESPONDER(connection->sm_role)){ 2416 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2417 } else { 2418 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2419 } 2420 2421 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2422 sm_timeout_reset(connection); 2423 break; 2424 } 2425 2426 #endif 2427 2428 #ifdef ENABLE_LE_PERIPHERAL 2429 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2430 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2431 2432 // start with initiator key dist flags 2433 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2434 2435 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2436 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2437 if (setup->sm_use_secure_connections){ 2438 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2439 } 2440 #endif 2441 // setup in response 2442 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); 2443 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); 2444 2445 // update key distribution after ENC was dropped 2446 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2447 2448 if (setup->sm_use_secure_connections){ 2449 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2450 } else { 2451 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2452 } 2453 2454 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2455 sm_timeout_reset(connection); 2456 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2457 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2458 sm_trigger_user_response(connection); 2459 } 2460 return; 2461 #endif 2462 2463 case SM_PH2_SEND_PAIRING_RANDOM: { 2464 uint8_t buffer[17]; 2465 buffer[0] = SM_CODE_PAIRING_RANDOM; 2466 reverse_128(setup->sm_local_random, &buffer[1]); 2467 if (IS_RESPONDER(connection->sm_role)){ 2468 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2469 } else { 2470 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2471 } 2472 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2473 sm_timeout_reset(connection); 2474 break; 2475 } 2476 2477 case SM_PH2_C1_GET_ENC_A: 2478 // already busy? 2479 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2480 // calculate confirm using aes128 engine - step 1 2481 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); 2482 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2483 sm_aes128_state = SM_AES128_ACTIVE; 2484 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2485 break; 2486 2487 case SM_PH2_C1_GET_ENC_C: 2488 // already busy? 2489 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2490 // calculate m_confirm using aes128 engine - step 1 2491 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); 2492 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2493 sm_aes128_state = SM_AES128_ACTIVE; 2494 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2495 break; 2496 2497 case SM_PH2_CALC_STK: 2498 // already busy? 2499 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2500 // calculate STK 2501 if (IS_RESPONDER(connection->sm_role)){ 2502 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2503 } else { 2504 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2505 } 2506 connection->sm_engine_state = SM_PH2_W4_STK; 2507 sm_aes128_state = SM_AES128_ACTIVE; 2508 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2509 break; 2510 2511 case SM_PH3_Y_GET_ENC: 2512 // already busy? 2513 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2514 // PH3B2 - calculate Y from - enc 2515 // Y = dm(DHK, Rand) 2516 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2517 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2518 sm_aes128_state = SM_AES128_ACTIVE; 2519 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); 2520 break; 2521 2522 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2523 uint8_t buffer[17]; 2524 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2525 reverse_128(setup->sm_local_confirm, &buffer[1]); 2526 if (IS_RESPONDER(connection->sm_role)){ 2527 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2528 } else { 2529 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2530 } 2531 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2532 sm_timeout_reset(connection); 2533 return; 2534 } 2535 #ifdef ENABLE_LE_PERIPHERAL 2536 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2537 sm_key_t stk_flipped; 2538 reverse_128(setup->sm_ltk, stk_flipped); 2539 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2540 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2541 return; 2542 } 2543 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2544 sm_key_t ltk_flipped; 2545 reverse_128(setup->sm_ltk, ltk_flipped); 2546 connection->sm_engine_state = SM_RESPONDER_IDLE; 2547 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2548 sm_done_for_handle(connection->sm_handle); 2549 return; 2550 } 2551 case SM_RESPONDER_PH4_Y_GET_ENC: 2552 // already busy? 2553 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2554 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2555 // Y = dm(DHK, Rand) 2556 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2557 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2558 sm_aes128_state = SM_AES128_ACTIVE; 2559 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); 2560 return; 2561 #endif 2562 #ifdef ENABLE_LE_CENTRAL 2563 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2564 sm_key_t stk_flipped; 2565 reverse_128(setup->sm_ltk, stk_flipped); 2566 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2567 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2568 return; 2569 } 2570 #endif 2571 2572 case SM_PH3_DISTRIBUTE_KEYS: 2573 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2574 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2575 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2576 uint8_t buffer[17]; 2577 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2578 reverse_128(setup->sm_ltk, &buffer[1]); 2579 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2580 sm_timeout_reset(connection); 2581 return; 2582 } 2583 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2584 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2585 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2586 uint8_t buffer[11]; 2587 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2588 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2589 reverse_64(setup->sm_local_rand, &buffer[3]); 2590 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2591 sm_timeout_reset(connection); 2592 return; 2593 } 2594 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2595 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2596 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2597 uint8_t buffer[17]; 2598 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2599 reverse_128(sm_persistent_irk, &buffer[1]); 2600 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2601 sm_timeout_reset(connection); 2602 return; 2603 } 2604 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2605 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2606 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2607 bd_addr_t local_address; 2608 uint8_t buffer[8]; 2609 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2610 switch (gap_random_address_get_mode()){ 2611 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2612 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2613 // public or static random 2614 gap_le_get_own_address(&buffer[1], local_address); 2615 break; 2616 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2617 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2618 // fallback to public 2619 gap_local_bd_addr(local_address); 2620 buffer[1] = 0; 2621 break; 2622 } 2623 reverse_bd_addr(local_address, &buffer[2]); 2624 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2625 sm_timeout_reset(connection); 2626 return; 2627 } 2628 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2629 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2630 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2631 2632 #ifdef ENABLE_LE_SIGNED_WRITE 2633 // hack to reproduce test runs 2634 if (test_use_fixed_local_csrk){ 2635 memset(setup->sm_local_csrk, 0xcc, 16); 2636 } 2637 2638 // store local CSRK 2639 if (setup->sm_le_device_index >= 0){ 2640 log_info("sm: store local CSRK"); 2641 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2642 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2643 } 2644 #endif 2645 2646 uint8_t buffer[17]; 2647 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2648 reverse_128(setup->sm_local_csrk, &buffer[1]); 2649 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2650 sm_timeout_reset(connection); 2651 return; 2652 } 2653 2654 // keys are sent 2655 if (IS_RESPONDER(connection->sm_role)){ 2656 // slave -> receive master keys if any 2657 if (sm_key_distribution_all_received(connection)){ 2658 sm_key_distribution_handle_all_received(connection); 2659 connection->sm_engine_state = SM_RESPONDER_IDLE; 2660 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2661 sm_done_for_handle(connection->sm_handle); 2662 } else { 2663 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2664 } 2665 } else { 2666 // master -> all done 2667 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2668 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2669 sm_done_for_handle(connection->sm_handle); 2670 } 2671 break; 2672 2673 default: 2674 break; 2675 } 2676 2677 // check again if active connection was released 2678 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2679 } 2680 } 2681 2682 // sm_aes128_state stays active 2683 static void sm_handle_encryption_result_enc_a(void *arg){ 2684 sm_connection_t * connection = (sm_connection_t*) arg; 2685 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2686 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); 2687 } 2688 2689 static void sm_handle_encryption_result_enc_b(void *arg){ 2690 sm_connection_t * connection = (sm_connection_t*) arg; 2691 sm_aes128_state = SM_AES128_IDLE; 2692 log_info_key("c1!", setup->sm_local_confirm); 2693 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2694 sm_run(); 2695 } 2696 2697 // sm_aes128_state stays active 2698 static void sm_handle_encryption_result_enc_c(void *arg){ 2699 sm_connection_t * connection = (sm_connection_t*) arg; 2700 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2701 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); 2702 } 2703 2704 static void sm_handle_encryption_result_enc_d(void * arg){ 2705 sm_connection_t * connection = (sm_connection_t*) arg; 2706 sm_aes128_state = SM_AES128_IDLE; 2707 log_info_key("c1!", sm_aes128_ciphertext); 2708 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2709 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2710 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2711 sm_run(); 2712 return; 2713 } 2714 if (IS_RESPONDER(connection->sm_role)){ 2715 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2716 sm_run(); 2717 } else { 2718 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2719 sm_aes128_state = SM_AES128_ACTIVE; 2720 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2721 } 2722 } 2723 2724 static void sm_handle_encryption_result_enc_stk(void *arg){ 2725 sm_connection_t * connection = (sm_connection_t*) arg; 2726 sm_aes128_state = SM_AES128_IDLE; 2727 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2728 log_info_key("stk", setup->sm_ltk); 2729 if (IS_RESPONDER(connection->sm_role)){ 2730 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2731 } else { 2732 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2733 } 2734 sm_run(); 2735 } 2736 2737 // sm_aes128_state stays active 2738 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2739 sm_connection_t * connection = (sm_connection_t*) arg; 2740 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2741 log_info_hex16("y", setup->sm_local_y); 2742 // PH3B3 - calculate EDIV 2743 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2744 log_info_hex16("ediv", setup->sm_local_ediv); 2745 // PH3B4 - calculate LTK - enc 2746 // LTK = d1(ER, DIV, 0)) 2747 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2748 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); 2749 } 2750 2751 #ifdef ENABLE_LE_PERIPHERAL 2752 // sm_aes128_state stays active 2753 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2754 sm_connection_t * connection = (sm_connection_t*) arg; 2755 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2756 log_info_hex16("y", setup->sm_local_y); 2757 2758 // PH3B3 - calculate DIV 2759 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2760 log_info_hex16("ediv", setup->sm_local_ediv); 2761 // PH3B4 - calculate LTK - enc 2762 // LTK = d1(ER, DIV, 0)) 2763 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2764 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); 2765 } 2766 #endif 2767 2768 // sm_aes128_state stays active 2769 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2770 sm_connection_t * connection = (sm_connection_t*) arg; 2771 log_info_key("ltk", setup->sm_ltk); 2772 // calc CSRK next 2773 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2774 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); 2775 } 2776 2777 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2778 sm_connection_t * connection = (sm_connection_t*) arg; 2779 sm_aes128_state = SM_AES128_IDLE; 2780 log_info_key("csrk", setup->sm_local_csrk); 2781 if (setup->sm_key_distribution_send_set){ 2782 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2783 } else { 2784 // no keys to send, just continue 2785 if (IS_RESPONDER(connection->sm_role)){ 2786 // slave -> receive master keys 2787 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2788 } else { 2789 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2790 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2791 } else { 2792 // master -> all done 2793 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2794 sm_done_for_handle(connection->sm_handle); 2795 } 2796 } 2797 } 2798 sm_run(); 2799 } 2800 2801 #ifdef ENABLE_LE_PERIPHERAL 2802 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2803 sm_connection_t * connection = (sm_connection_t*) arg; 2804 sm_aes128_state = SM_AES128_IDLE; 2805 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2806 log_info_key("ltk", setup->sm_ltk); 2807 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2808 sm_run(); 2809 } 2810 #endif 2811 2812 static void sm_handle_encryption_result_address_resolution(void *arg){ 2813 UNUSED(arg); 2814 sm_aes128_state = SM_AES128_IDLE; 2815 sm_address_resolution_ah_calculation_active = 0; 2816 // compare calulated address against connecting device 2817 uint8_t * hash = &sm_aes128_ciphertext[13]; 2818 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2819 log_info("LE Device Lookup: matched resolvable private address"); 2820 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2821 sm_run(); 2822 return; 2823 } 2824 // no match, try next 2825 sm_address_resolution_test++; 2826 sm_run(); 2827 } 2828 2829 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2830 UNUSED(arg); 2831 sm_aes128_state = SM_AES128_IDLE; 2832 log_info_key("irk", sm_persistent_irk); 2833 dkg_state = DKG_CALC_DHK; 2834 sm_run(); 2835 } 2836 2837 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2838 UNUSED(arg); 2839 sm_aes128_state = SM_AES128_IDLE; 2840 log_info_key("dhk", sm_persistent_dhk); 2841 dkg_state = DKG_READY; 2842 sm_run(); 2843 } 2844 2845 static void sm_handle_encryption_result_rau(void *arg){ 2846 UNUSED(arg); 2847 sm_aes128_state = SM_AES128_IDLE; 2848 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2849 rau_state = RAU_SET_ADDRESS; 2850 sm_run(); 2851 } 2852 2853 static void sm_handle_random_result_rau(void * arg){ 2854 UNUSED(arg); 2855 // non-resolvable vs. resolvable 2856 switch (gap_random_adress_type){ 2857 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2858 // resolvable: use random as prand and calc address hash 2859 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2860 sm_random_address[0] &= 0x3f; 2861 sm_random_address[0] |= 0x40; 2862 rau_state = RAU_GET_ENC; 2863 break; 2864 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2865 default: 2866 // "The two most significant bits of the address shall be equal to ‘0’"" 2867 sm_random_address[0] &= 0x3f; 2868 rau_state = RAU_SET_ADDRESS; 2869 break; 2870 } 2871 sm_run(); 2872 } 2873 2874 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2875 static void sm_handle_random_result_sc_get_random(void * arg){ 2876 sm_connection_t * connection = (sm_connection_t*) arg; 2877 2878 // OOB 2879 if (setup->sm_stk_generation_method == OOB){ 2880 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2881 sm_run(); 2882 return; 2883 } 2884 2885 // initiator & jw/nc -> send pairing random 2886 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2887 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2888 } else { 2889 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2890 } 2891 sm_run(); 2892 } 2893 #endif 2894 2895 static void sm_handle_random_result_ph2_random(void * arg){ 2896 sm_connection_t * connection = (sm_connection_t*) arg; 2897 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2898 sm_run(); 2899 } 2900 2901 static void sm_handle_random_result_ph2_tk(void * arg){ 2902 sm_connection_t * connection = (sm_connection_t*) arg; 2903 sm_reset_tk(); 2904 uint32_t tk; 2905 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2906 // map random to 0-999999 without speding much cycles on a modulus operation 2907 tk = little_endian_read_32(sm_random_data,0); 2908 tk = tk & 0xfffff; // 1048575 2909 if (tk >= 999999){ 2910 tk = tk - 999999; 2911 } 2912 } else { 2913 // override with pre-defined passkey 2914 tk = sm_fixed_passkey_in_display_role; 2915 } 2916 big_endian_store_32(setup->sm_tk, 12, tk); 2917 if (IS_RESPONDER(connection->sm_role)){ 2918 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2919 } else { 2920 if (setup->sm_use_secure_connections){ 2921 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2922 } else { 2923 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2924 sm_trigger_user_response(connection); 2925 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2926 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2927 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2928 } 2929 } 2930 } 2931 sm_run(); 2932 } 2933 2934 static void sm_handle_random_result_ph3_div(void * arg){ 2935 sm_connection_t * connection = (sm_connection_t*) arg; 2936 // use 16 bit from random value as div 2937 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2938 log_info_hex16("div", setup->sm_local_div); 2939 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2940 sm_run(); 2941 } 2942 2943 static void sm_handle_random_result_ph3_random(void * arg){ 2944 sm_connection_t * connection = (sm_connection_t*) arg; 2945 reverse_64(sm_random_data, setup->sm_local_rand); 2946 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2947 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2948 // no db for authenticated flag hack: store flag in bit 4 of LSB 2949 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2950 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2951 } 2952 static void sm_validate_er_ir(void){ 2953 // warn about default ER/IR 2954 int warning = 0; 2955 if (sm_ir_is_default()){ 2956 warning = 1; 2957 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 2958 } 2959 if (sm_er_is_default()){ 2960 warning = 1; 2961 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 2962 } 2963 if (warning) { 2964 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 2965 } 2966 } 2967 2968 static void sm_handle_random_result_ir(void *arg){ 2969 sm_persistent_keys_random_active = 0; 2970 if (arg){ 2971 // key generated, store in tlv 2972 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2973 log_info("Generated IR key. Store in TLV status: %d", status); 2974 } 2975 log_info_key("IR", sm_persistent_ir); 2976 dkg_state = DKG_CALC_IRK; 2977 sm_run(); 2978 } 2979 2980 static void sm_handle_random_result_er(void *arg){ 2981 sm_persistent_keys_random_active = 0; 2982 if (arg){ 2983 // key generated, store in tlv 2984 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2985 log_info("Generated ER key. Store in TLV status: %d", status); 2986 } 2987 log_info_key("ER", sm_persistent_er); 2988 2989 // try load ir 2990 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2991 if (key_size == 16){ 2992 // ok, let's continue 2993 log_info("IR from TLV"); 2994 sm_handle_random_result_ir( NULL ); 2995 } else { 2996 // invalid, generate new random one 2997 sm_persistent_keys_random_active = 1; 2998 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 2999 } 3000 } 3001 3002 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3003 3004 UNUSED(channel); // ok: there is no channel 3005 UNUSED(size); // ok: fixed format HCI events 3006 3007 sm_connection_t * sm_conn; 3008 hci_con_handle_t con_handle; 3009 3010 switch (packet_type) { 3011 3012 case HCI_EVENT_PACKET: 3013 switch (hci_event_packet_get_type(packet)) { 3014 3015 case BTSTACK_EVENT_STATE: 3016 // bt stack activated, get started 3017 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3018 log_info("HCI Working!"); 3019 3020 // setup IR/ER with TLV 3021 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3022 if (sm_tlv_impl){ 3023 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3024 if (key_size == 16){ 3025 // ok, let's continue 3026 log_info("ER from TLV"); 3027 sm_handle_random_result_er( NULL ); 3028 } else { 3029 // invalid, generate random one 3030 sm_persistent_keys_random_active = 1; 3031 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3032 } 3033 } else { 3034 sm_validate_er_ir(); 3035 dkg_state = DKG_CALC_IRK; 3036 } 3037 } 3038 break; 3039 3040 case HCI_EVENT_LE_META: 3041 switch (packet[2]) { 3042 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3043 3044 log_info("sm: connected"); 3045 3046 if (packet[3]) return; // connection failed 3047 3048 con_handle = little_endian_read_16(packet, 4); 3049 sm_conn = sm_get_connection_for_handle(con_handle); 3050 if (!sm_conn) break; 3051 3052 sm_conn->sm_handle = con_handle; 3053 sm_conn->sm_role = packet[6]; 3054 sm_conn->sm_peer_addr_type = packet[7]; 3055 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3056 3057 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3058 3059 // reset security properties 3060 sm_conn->sm_connection_encrypted = 0; 3061 sm_conn->sm_connection_authenticated = 0; 3062 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3063 sm_conn->sm_le_db_index = -1; 3064 3065 // prepare CSRK lookup (does not involve setup) 3066 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3067 3068 // just connected -> everything else happens in sm_run() 3069 if (IS_RESPONDER(sm_conn->sm_role)){ 3070 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3071 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3072 if (sm_slave_request_security) { 3073 // request security if requested by app 3074 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3075 } else { 3076 // otherwise, wait for pairing request 3077 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3078 } 3079 } 3080 break; 3081 } else { 3082 // master 3083 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3084 } 3085 break; 3086 3087 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3088 con_handle = little_endian_read_16(packet, 3); 3089 sm_conn = sm_get_connection_for_handle(con_handle); 3090 if (!sm_conn) break; 3091 3092 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3093 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3094 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3095 break; 3096 } 3097 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3098 // PH2 SEND LTK as we need to exchange keys in PH3 3099 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3100 break; 3101 } 3102 3103 // store rand and ediv 3104 reverse_64(&packet[5], sm_conn->sm_local_rand); 3105 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3106 3107 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3108 // potentially stored LTK is from the master 3109 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3110 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3111 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3112 break; 3113 } 3114 // additionally check if remote is in LE Device DB if requested 3115 switch(sm_conn->sm_irk_lookup_state){ 3116 case IRK_LOOKUP_FAILED: 3117 log_info("LTK Request: device not in device db"); 3118 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3119 break; 3120 case IRK_LOOKUP_SUCCEEDED: 3121 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3122 break; 3123 default: 3124 // wait for irk look doen 3125 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3126 break; 3127 } 3128 break; 3129 } 3130 3131 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3132 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3133 #else 3134 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3135 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3136 #endif 3137 break; 3138 3139 default: 3140 break; 3141 } 3142 break; 3143 3144 case HCI_EVENT_ENCRYPTION_CHANGE: 3145 con_handle = little_endian_read_16(packet, 3); 3146 sm_conn = sm_get_connection_for_handle(con_handle); 3147 if (!sm_conn) break; 3148 3149 sm_conn->sm_connection_encrypted = packet[5]; 3150 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3151 sm_conn->sm_actual_encryption_key_size); 3152 log_info("event handler, state %u", sm_conn->sm_engine_state); 3153 3154 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3155 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3156 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3157 // notify client, if pairing was requested before 3158 if (sm_conn->sm_pairing_requested){ 3159 sm_conn->sm_pairing_requested = 0; 3160 if (sm_conn->sm_connection_encrypted){ 3161 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3162 } else { 3163 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3164 } 3165 } 3166 sm_done_for_handle(sm_conn->sm_handle); 3167 break; 3168 } 3169 3170 if (!sm_conn->sm_connection_encrypted) break; 3171 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3172 3173 // continue pairing 3174 switch (sm_conn->sm_engine_state){ 3175 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3176 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3177 sm_done_for_handle(sm_conn->sm_handle); 3178 break; 3179 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3180 if (IS_RESPONDER(sm_conn->sm_role)){ 3181 // slave 3182 if (setup->sm_use_secure_connections){ 3183 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3184 } else { 3185 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3186 } 3187 } else { 3188 // master 3189 if (sm_key_distribution_all_received(sm_conn)){ 3190 // skip receiving keys as there are none 3191 sm_key_distribution_handle_all_received(sm_conn); 3192 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3193 } else { 3194 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3195 } 3196 } 3197 break; 3198 default: 3199 break; 3200 } 3201 break; 3202 3203 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3204 con_handle = little_endian_read_16(packet, 3); 3205 sm_conn = sm_get_connection_for_handle(con_handle); 3206 if (!sm_conn) break; 3207 3208 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3209 log_info("event handler, state %u", sm_conn->sm_engine_state); 3210 // continue if part of initial pairing 3211 switch (sm_conn->sm_engine_state){ 3212 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3213 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3214 sm_done_for_handle(sm_conn->sm_handle); 3215 break; 3216 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3217 if (IS_RESPONDER(sm_conn->sm_role)){ 3218 // slave 3219 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3220 } else { 3221 // master 3222 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3223 } 3224 break; 3225 default: 3226 break; 3227 } 3228 break; 3229 3230 3231 case HCI_EVENT_DISCONNECTION_COMPLETE: 3232 con_handle = little_endian_read_16(packet, 3); 3233 sm_done_for_handle(con_handle); 3234 sm_conn = sm_get_connection_for_handle(con_handle); 3235 if (!sm_conn) break; 3236 3237 // delete stored bonding on disconnect with authentication failure in ph0 3238 if (sm_conn->sm_role == 0 3239 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3240 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3241 le_device_db_remove(sm_conn->sm_le_db_index); 3242 } 3243 3244 // pairing failed, if it was ongoing 3245 switch (sm_conn->sm_engine_state){ 3246 case SM_GENERAL_IDLE: 3247 case SM_INITIATOR_CONNECTED: 3248 case SM_RESPONDER_IDLE: 3249 break; 3250 default: 3251 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3252 break; 3253 } 3254 3255 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3256 sm_conn->sm_handle = 0; 3257 break; 3258 3259 case HCI_EVENT_COMMAND_COMPLETE: 3260 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3261 // set local addr for le device db 3262 bd_addr_t addr; 3263 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3264 le_device_db_set_local_bd_addr(addr); 3265 } 3266 break; 3267 default: 3268 break; 3269 } 3270 break; 3271 default: 3272 break; 3273 } 3274 3275 sm_run(); 3276 } 3277 3278 static inline int sm_calc_actual_encryption_key_size(int other){ 3279 if (other < sm_min_encryption_key_size) return 0; 3280 if (other < sm_max_encryption_key_size) return other; 3281 return sm_max_encryption_key_size; 3282 } 3283 3284 3285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3286 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3287 switch (method){ 3288 case JUST_WORKS: 3289 case NUMERIC_COMPARISON: 3290 return 1; 3291 default: 3292 return 0; 3293 } 3294 } 3295 // responder 3296 3297 static int sm_passkey_used(stk_generation_method_t method){ 3298 switch (method){ 3299 case PK_RESP_INPUT: 3300 return 1; 3301 default: 3302 return 0; 3303 } 3304 } 3305 3306 static int sm_passkey_entry(stk_generation_method_t method){ 3307 switch (method){ 3308 case PK_RESP_INPUT: 3309 case PK_INIT_INPUT: 3310 case PK_BOTH_INPUT: 3311 return 1; 3312 default: 3313 return 0; 3314 } 3315 } 3316 3317 #endif 3318 3319 /** 3320 * @return ok 3321 */ 3322 static int sm_validate_stk_generation_method(void){ 3323 // check if STK generation method is acceptable by client 3324 switch (setup->sm_stk_generation_method){ 3325 case JUST_WORKS: 3326 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3327 case PK_RESP_INPUT: 3328 case PK_INIT_INPUT: 3329 case PK_BOTH_INPUT: 3330 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3331 case OOB: 3332 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3333 case NUMERIC_COMPARISON: 3334 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3335 default: 3336 return 0; 3337 } 3338 } 3339 3340 // size of complete sm_pdu used to validate input 3341 static const uint8_t sm_pdu_size[] = { 3342 0, // 0x00 invalid opcode 3343 7, // 0x01 pairing request 3344 7, // 0x02 pairing response 3345 17, // 0x03 pairing confirm 3346 17, // 0x04 pairing random 3347 2, // 0x05 pairing failed 3348 17, // 0x06 encryption information 3349 11, // 0x07 master identification 3350 17, // 0x08 identification information 3351 8, // 0x09 identify address information 3352 17, // 0x0a signing information 3353 2, // 0x0b security request 3354 65, // 0x0c pairing public key 3355 17, // 0x0d pairing dhk check 3356 2, // 0x0e keypress notification 3357 }; 3358 3359 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3360 3361 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3362 sm_run(); 3363 } 3364 3365 if (packet_type != SM_DATA_PACKET) return; 3366 if (size == 0) return; 3367 3368 uint8_t sm_pdu_code = packet[0]; 3369 3370 // validate pdu size 3371 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3372 if (sm_pdu_size[sm_pdu_code] != size) return; 3373 3374 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3375 if (!sm_conn) return; 3376 3377 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3378 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3379 sm_done_for_handle(con_handle); 3380 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3381 return; 3382 } 3383 3384 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3385 3386 int err; 3387 UNUSED(err); 3388 3389 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3390 uint8_t buffer[5]; 3391 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3392 buffer[1] = 3; 3393 little_endian_store_16(buffer, 2, con_handle); 3394 buffer[4] = packet[1]; 3395 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3396 return; 3397 } 3398 3399 switch (sm_conn->sm_engine_state){ 3400 3401 // a sm timeout requries a new physical connection 3402 case SM_GENERAL_TIMEOUT: 3403 return; 3404 3405 #ifdef ENABLE_LE_CENTRAL 3406 3407 // Initiator 3408 case SM_INITIATOR_CONNECTED: 3409 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3410 sm_pdu_received_in_wrong_state(sm_conn); 3411 break; 3412 } 3413 3414 // IRK complete? 3415 switch (sm_conn->sm_irk_lookup_state){ 3416 case IRK_LOOKUP_FAILED: 3417 case IRK_LOOKUP_SUCCEEDED: 3418 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3419 break; 3420 default: 3421 break; 3422 } 3423 3424 // otherwise, store security request 3425 sm_conn->sm_security_request_received = 1; 3426 break; 3427 3428 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3429 // Core 5, Vol 3, Part H, 2.4.6: 3430 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3431 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3432 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3433 log_info("Ignoring Security Request"); 3434 break; 3435 } 3436 3437 // all other pdus are incorrect 3438 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3439 sm_pdu_received_in_wrong_state(sm_conn); 3440 break; 3441 } 3442 3443 // store pairing request 3444 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3445 err = sm_stk_generation_init(sm_conn); 3446 3447 #ifdef ENABLE_TESTING_SUPPORT 3448 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3449 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3450 err = test_pairing_failure; 3451 } 3452 #endif 3453 3454 if (err){ 3455 setup->sm_pairing_failed_reason = err; 3456 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3457 break; 3458 } 3459 3460 // generate random number first, if we need to show passkey 3461 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3462 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3463 break; 3464 } 3465 3466 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3467 if (setup->sm_use_secure_connections){ 3468 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3469 if (setup->sm_stk_generation_method == JUST_WORKS){ 3470 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3471 sm_trigger_user_response(sm_conn); 3472 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3473 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3474 } 3475 } else { 3476 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3477 } 3478 break; 3479 } 3480 #endif 3481 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3482 sm_trigger_user_response(sm_conn); 3483 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3484 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3485 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3486 } 3487 break; 3488 3489 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3490 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3491 sm_pdu_received_in_wrong_state(sm_conn); 3492 break; 3493 } 3494 3495 // store s_confirm 3496 reverse_128(&packet[1], setup->sm_peer_confirm); 3497 3498 #ifdef ENABLE_TESTING_SUPPORT 3499 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3500 log_info("testing_support: reset confirm value"); 3501 memset(setup->sm_peer_confirm, 0, 16); 3502 } 3503 #endif 3504 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3505 break; 3506 3507 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3508 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3509 sm_pdu_received_in_wrong_state(sm_conn); 3510 break;; 3511 } 3512 3513 // received random value 3514 reverse_128(&packet[1], setup->sm_peer_random); 3515 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3516 break; 3517 #endif 3518 3519 #ifdef ENABLE_LE_PERIPHERAL 3520 // Responder 3521 case SM_RESPONDER_IDLE: 3522 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3523 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3524 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3525 sm_pdu_received_in_wrong_state(sm_conn); 3526 break;; 3527 } 3528 3529 // store pairing request 3530 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3531 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3532 break; 3533 #endif 3534 3535 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3536 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3537 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3538 sm_pdu_received_in_wrong_state(sm_conn); 3539 break; 3540 } 3541 3542 // store public key for DH Key calculation 3543 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3544 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3545 3546 // validate public key 3547 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3548 if (err){ 3549 log_error("sm: peer public key invalid %x", err); 3550 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3551 break; 3552 } 3553 3554 // start calculating dhkey 3555 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3556 3557 3558 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3559 if (IS_RESPONDER(sm_conn->sm_role)){ 3560 // responder 3561 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3562 } else { 3563 // initiator 3564 // stk generation method 3565 // passkey entry: notify app to show passkey or to request passkey 3566 switch (setup->sm_stk_generation_method){ 3567 case JUST_WORKS: 3568 case NUMERIC_COMPARISON: 3569 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3570 break; 3571 case PK_RESP_INPUT: 3572 sm_sc_start_calculating_local_confirm(sm_conn); 3573 break; 3574 case PK_INIT_INPUT: 3575 case PK_BOTH_INPUT: 3576 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3577 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3578 break; 3579 } 3580 sm_sc_start_calculating_local_confirm(sm_conn); 3581 break; 3582 case OOB: 3583 // generate Nx 3584 log_info("Generate Na"); 3585 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3586 break; 3587 } 3588 } 3589 break; 3590 3591 case SM_SC_W4_CONFIRMATION: 3592 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3593 sm_pdu_received_in_wrong_state(sm_conn); 3594 break; 3595 } 3596 // received confirm value 3597 reverse_128(&packet[1], setup->sm_peer_confirm); 3598 3599 #ifdef ENABLE_TESTING_SUPPORT 3600 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3601 log_info("testing_support: reset confirm value"); 3602 memset(setup->sm_peer_confirm, 0, 16); 3603 } 3604 #endif 3605 if (IS_RESPONDER(sm_conn->sm_role)){ 3606 // responder 3607 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3608 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3609 // still waiting for passkey 3610 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3611 break; 3612 } 3613 } 3614 sm_sc_start_calculating_local_confirm(sm_conn); 3615 } else { 3616 // initiator 3617 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3618 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3619 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3620 } else { 3621 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3622 } 3623 } 3624 break; 3625 3626 case SM_SC_W4_PAIRING_RANDOM: 3627 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3628 sm_pdu_received_in_wrong_state(sm_conn); 3629 break; 3630 } 3631 3632 // received random value 3633 reverse_128(&packet[1], setup->sm_peer_nonce); 3634 3635 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3636 // only check for JUST WORK/NC in initiator role OR passkey entry 3637 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3638 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3639 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3640 break; 3641 } 3642 3643 // OOB 3644 if (setup->sm_stk_generation_method == OOB){ 3645 3646 // setup local random, set to zero if remote did not receive our data 3647 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3648 if (IS_RESPONDER(sm_conn->sm_role)){ 3649 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3650 log_info("Reset rb as A does not have OOB data"); 3651 memset(setup->sm_rb, 0, 16); 3652 } else { 3653 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3654 log_info("Use stored rb"); 3655 log_info_hexdump(setup->sm_rb, 16); 3656 } 3657 } else { 3658 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3659 log_info("Reset ra as B does not have OOB data"); 3660 memset(setup->sm_ra, 0, 16); 3661 } else { 3662 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3663 log_info("Use stored ra"); 3664 log_info_hexdump(setup->sm_ra, 16); 3665 } 3666 } 3667 3668 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3669 if (setup->sm_have_oob_data){ 3670 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3671 break; 3672 } 3673 } 3674 3675 // TODO: we only get here for Responder role with JW/NC 3676 sm_sc_state_after_receiving_random(sm_conn); 3677 break; 3678 3679 case SM_SC_W2_CALCULATE_G2: 3680 case SM_SC_W4_CALCULATE_G2: 3681 case SM_SC_W4_CALCULATE_DHKEY: 3682 case SM_SC_W2_CALCULATE_F5_SALT: 3683 case SM_SC_W4_CALCULATE_F5_SALT: 3684 case SM_SC_W2_CALCULATE_F5_MACKEY: 3685 case SM_SC_W4_CALCULATE_F5_MACKEY: 3686 case SM_SC_W2_CALCULATE_F5_LTK: 3687 case SM_SC_W4_CALCULATE_F5_LTK: 3688 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3689 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3690 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3691 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3692 sm_pdu_received_in_wrong_state(sm_conn); 3693 break; 3694 } 3695 // store DHKey Check 3696 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3697 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3698 3699 // have we been only waiting for dhkey check command? 3700 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3701 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3702 } 3703 break; 3704 #endif 3705 3706 #ifdef ENABLE_LE_PERIPHERAL 3707 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3708 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3709 sm_pdu_received_in_wrong_state(sm_conn); 3710 break; 3711 } 3712 3713 // received confirm value 3714 reverse_128(&packet[1], setup->sm_peer_confirm); 3715 3716 #ifdef ENABLE_TESTING_SUPPORT 3717 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3718 log_info("testing_support: reset confirm value"); 3719 memset(setup->sm_peer_confirm, 0, 16); 3720 } 3721 #endif 3722 // notify client to hide shown passkey 3723 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3724 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3725 } 3726 3727 // handle user cancel pairing? 3728 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3729 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3730 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3731 break; 3732 } 3733 3734 // wait for user action? 3735 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3736 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3737 break; 3738 } 3739 3740 // calculate and send local_confirm 3741 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3742 break; 3743 3744 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3745 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3746 sm_pdu_received_in_wrong_state(sm_conn); 3747 break;; 3748 } 3749 3750 // received random value 3751 reverse_128(&packet[1], setup->sm_peer_random); 3752 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3753 break; 3754 #endif 3755 3756 case SM_PH3_RECEIVE_KEYS: 3757 switch(sm_pdu_code){ 3758 case SM_CODE_ENCRYPTION_INFORMATION: 3759 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3760 reverse_128(&packet[1], setup->sm_peer_ltk); 3761 break; 3762 3763 case SM_CODE_MASTER_IDENTIFICATION: 3764 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3765 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3766 reverse_64(&packet[3], setup->sm_peer_rand); 3767 break; 3768 3769 case SM_CODE_IDENTITY_INFORMATION: 3770 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3771 reverse_128(&packet[1], setup->sm_peer_irk); 3772 break; 3773 3774 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3775 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3776 setup->sm_peer_addr_type = packet[1]; 3777 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3778 break; 3779 3780 case SM_CODE_SIGNING_INFORMATION: 3781 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3782 reverse_128(&packet[1], setup->sm_peer_csrk); 3783 break; 3784 default: 3785 // Unexpected PDU 3786 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3787 break; 3788 } 3789 // done with key distribution? 3790 if (sm_key_distribution_all_received(sm_conn)){ 3791 3792 sm_key_distribution_handle_all_received(sm_conn); 3793 3794 if (IS_RESPONDER(sm_conn->sm_role)){ 3795 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3796 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3797 } else { 3798 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3799 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3800 sm_done_for_handle(sm_conn->sm_handle); 3801 } 3802 } else { 3803 if (setup->sm_use_secure_connections){ 3804 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3805 } else { 3806 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3807 } 3808 } 3809 } 3810 break; 3811 default: 3812 // Unexpected PDU 3813 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3814 break; 3815 } 3816 3817 // try to send preparared packet 3818 sm_run(); 3819 } 3820 3821 // Security Manager Client API 3822 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3823 sm_get_oob_data = get_oob_data_callback; 3824 } 3825 3826 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)){ 3827 sm_get_sc_oob_data = get_sc_oob_data_callback; 3828 } 3829 3830 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3831 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3832 } 3833 3834 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3835 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3836 } 3837 3838 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3839 sm_min_encryption_key_size = min_size; 3840 sm_max_encryption_key_size = max_size; 3841 } 3842 3843 void sm_set_authentication_requirements(uint8_t auth_req){ 3844 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3845 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3846 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3847 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3848 } 3849 #endif 3850 sm_auth_req = auth_req; 3851 } 3852 3853 void sm_set_io_capabilities(io_capability_t io_capability){ 3854 sm_io_capabilities = io_capability; 3855 } 3856 3857 #ifdef ENABLE_LE_PERIPHERAL 3858 void sm_set_request_security(int enable){ 3859 sm_slave_request_security = enable; 3860 } 3861 #endif 3862 3863 void sm_set_er(sm_key_t er){ 3864 memcpy(sm_persistent_er, er, 16); 3865 } 3866 3867 void sm_set_ir(sm_key_t ir){ 3868 memcpy(sm_persistent_ir, ir, 16); 3869 } 3870 3871 // Testing support only 3872 void sm_test_set_irk(sm_key_t irk){ 3873 memcpy(sm_persistent_irk, irk, 16); 3874 dkg_state = DKG_CALC_DHK; 3875 } 3876 3877 void sm_test_use_fixed_local_csrk(void){ 3878 test_use_fixed_local_csrk = 1; 3879 } 3880 3881 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3882 static void sm_ec_generated(void * arg){ 3883 UNUSED(arg); 3884 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3885 // trigger pairing if pending for ec key 3886 sm_run(); 3887 } 3888 static void sm_ec_generate_new_key(void){ 3889 log_info("sm: generate new ec key"); 3890 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3891 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3892 } 3893 #endif 3894 3895 #ifdef ENABLE_TESTING_SUPPORT 3896 void sm_test_set_pairing_failure(int reason){ 3897 test_pairing_failure = reason; 3898 } 3899 #endif 3900 3901 void sm_init(void){ 3902 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3903 sm_er_ir_set_default(); 3904 3905 // defaults 3906 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3907 | SM_STK_GENERATION_METHOD_OOB 3908 | SM_STK_GENERATION_METHOD_PASSKEY 3909 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3910 3911 sm_max_encryption_key_size = 16; 3912 sm_min_encryption_key_size = 7; 3913 3914 sm_fixed_passkey_in_display_role = 0xffffffff; 3915 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3916 3917 #ifdef USE_CMAC_ENGINE 3918 sm_cmac_active = 0; 3919 #endif 3920 dkg_state = DKG_W4_WORKING; 3921 rau_state = RAU_IDLE; 3922 sm_aes128_state = SM_AES128_IDLE; 3923 sm_address_resolution_test = -1; // no private address to resolve yet 3924 sm_address_resolution_ah_calculation_active = 0; 3925 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3926 sm_address_resolution_general_queue = NULL; 3927 3928 gap_random_adress_update_period = 15 * 60 * 1000L; 3929 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3930 3931 test_use_fixed_local_csrk = 0; 3932 3933 // register for HCI Events from HCI 3934 hci_event_callback_registration.callback = &sm_event_packet_handler; 3935 hci_add_event_handler(&hci_event_callback_registration); 3936 3937 // 3938 btstack_crypto_init(); 3939 3940 // init le_device_db 3941 le_device_db_init(); 3942 3943 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3944 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3945 3946 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3947 sm_ec_generate_new_key(); 3948 #endif 3949 } 3950 3951 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3952 sm_fixed_passkey_in_display_role = passkey; 3953 } 3954 3955 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3956 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3957 } 3958 3959 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3960 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3961 if (!hci_con) return NULL; 3962 return &hci_con->sm_connection; 3963 } 3964 3965 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3966 switch (sm_conn->sm_engine_state){ 3967 case SM_GENERAL_IDLE: 3968 case SM_RESPONDER_IDLE: 3969 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3970 sm_run(); 3971 break; 3972 default: 3973 break; 3974 } 3975 } 3976 3977 /** 3978 * @brief Trigger Security Request 3979 */ 3980 void sm_send_security_request(hci_con_handle_t con_handle){ 3981 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3982 if (!sm_conn) return; 3983 sm_send_security_request_for_connection(sm_conn); 3984 } 3985 3986 // request pairing 3987 void sm_request_pairing(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 3991 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3992 if (IS_RESPONDER(sm_conn->sm_role)){ 3993 sm_send_security_request_for_connection(sm_conn); 3994 } else { 3995 // used as a trigger to start central/master/initiator security procedures 3996 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3997 uint8_t ltk[16]; 3998 switch (sm_conn->sm_irk_lookup_state){ 3999 case IRK_LOOKUP_SUCCEEDED: 4000 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4001 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4002 log_info("have ltk %u", !sm_is_null_key(ltk)); 4003 // trigger 'pairing complete' event on encryption change 4004 sm_conn->sm_pairing_requested = 1; 4005 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4006 break; 4007 #endif 4008 /* explicit fall-through */ 4009 4010 case IRK_LOOKUP_FAILED: 4011 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4012 break; 4013 default: 4014 log_info("irk lookup pending"); 4015 sm_conn->sm_pairing_requested = 1; 4016 break; 4017 } 4018 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4019 sm_conn->sm_pairing_requested = 1; 4020 } 4021 } 4022 sm_run(); 4023 } 4024 4025 // called by client app on authorization request 4026 void sm_authorization_decline(hci_con_handle_t con_handle){ 4027 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4028 if (!sm_conn) return; // wrong connection 4029 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4030 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4031 } 4032 4033 void sm_authorization_grant(hci_con_handle_t con_handle){ 4034 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4035 if (!sm_conn) return; // wrong connection 4036 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4037 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4038 } 4039 4040 // GAP Bonding API 4041 4042 void sm_bonding_decline(hci_con_handle_t con_handle){ 4043 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4044 if (!sm_conn) return; // wrong connection 4045 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4046 log_info("decline, state %u", sm_conn->sm_engine_state); 4047 switch(sm_conn->sm_engine_state){ 4048 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4049 case SM_SC_W4_USER_RESPONSE: 4050 case SM_SC_W4_CONFIRMATION: 4051 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4052 #endif 4053 case SM_PH1_W4_USER_RESPONSE: 4054 switch (setup->sm_stk_generation_method){ 4055 case PK_RESP_INPUT: 4056 case PK_INIT_INPUT: 4057 case PK_BOTH_INPUT: 4058 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4059 break; 4060 case NUMERIC_COMPARISON: 4061 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4062 break; 4063 case JUST_WORKS: 4064 case OOB: 4065 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4066 break; 4067 } 4068 break; 4069 default: 4070 break; 4071 } 4072 sm_run(); 4073 } 4074 4075 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4076 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4077 if (!sm_conn) return; // wrong connection 4078 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4079 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4080 if (setup->sm_use_secure_connections){ 4081 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4082 } else { 4083 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4084 } 4085 } 4086 4087 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4088 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4089 sm_sc_prepare_dhkey_check(sm_conn); 4090 } 4091 #endif 4092 4093 sm_run(); 4094 } 4095 4096 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4097 // for now, it's the same 4098 sm_just_works_confirm(con_handle); 4099 } 4100 4101 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4102 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4103 if (!sm_conn) return; // wrong connection 4104 sm_reset_tk(); 4105 big_endian_store_32(setup->sm_tk, 12, passkey); 4106 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4107 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4108 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4109 } 4110 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4111 memcpy(setup->sm_ra, setup->sm_tk, 16); 4112 memcpy(setup->sm_rb, setup->sm_tk, 16); 4113 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4114 sm_sc_start_calculating_local_confirm(sm_conn); 4115 } 4116 #endif 4117 sm_run(); 4118 } 4119 4120 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4121 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4122 if (!sm_conn) return; // wrong connection 4123 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4124 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4125 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4126 switch (action){ 4127 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4128 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4129 flags |= (1 << action); 4130 break; 4131 case SM_KEYPRESS_PASSKEY_CLEARED: 4132 // clear counter, keypress & erased flags + set passkey cleared 4133 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4134 break; 4135 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4136 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4137 // erase actions queued 4138 num_actions--; 4139 if (num_actions == 0){ 4140 // clear counter, keypress & erased flags 4141 flags &= 0x19; 4142 } 4143 break; 4144 } 4145 num_actions++; 4146 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4147 break; 4148 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4149 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4150 // enter actions queued 4151 num_actions--; 4152 if (num_actions == 0){ 4153 // clear counter, keypress & erased flags 4154 flags &= 0x19; 4155 } 4156 break; 4157 } 4158 num_actions++; 4159 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4160 break; 4161 default: 4162 break; 4163 } 4164 setup->sm_keypress_notification = (num_actions << 5) | flags; 4165 sm_run(); 4166 } 4167 4168 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4169 static void sm_handle_random_result_oob(void * arg){ 4170 UNUSED(arg); 4171 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4172 sm_run(); 4173 } 4174 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4175 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4176 sm_sc_oob_callback = callback; 4177 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4178 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4179 return 0; 4180 } 4181 #endif 4182 4183 /** 4184 * @brief Get Identity Resolving state 4185 * @param con_handle 4186 * @return irk_lookup_state_t 4187 */ 4188 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4189 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4190 if (!sm_conn) return IRK_LOOKUP_IDLE; 4191 return sm_conn->sm_irk_lookup_state; 4192 } 4193 4194 /** 4195 * @brief Identify device in LE Device DB 4196 * @param handle 4197 * @returns index from le_device_db or -1 if not found/identified 4198 */ 4199 int sm_le_device_index(hci_con_handle_t con_handle ){ 4200 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4201 if (!sm_conn) return -1; 4202 return sm_conn->sm_le_db_index; 4203 } 4204 4205 static int gap_random_address_type_requires_updates(void){ 4206 switch (gap_random_adress_type){ 4207 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4208 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4209 return 0; 4210 default: 4211 return 1; 4212 } 4213 } 4214 4215 static uint8_t own_address_type(void){ 4216 switch (gap_random_adress_type){ 4217 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4218 return BD_ADDR_TYPE_LE_PUBLIC; 4219 default: 4220 return BD_ADDR_TYPE_LE_RANDOM; 4221 } 4222 } 4223 4224 // GAP LE API 4225 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4226 gap_random_address_update_stop(); 4227 gap_random_adress_type = random_address_type; 4228 hci_le_set_own_address_type(own_address_type()); 4229 if (!gap_random_address_type_requires_updates()) return; 4230 gap_random_address_update_start(); 4231 gap_random_address_trigger(); 4232 } 4233 4234 gap_random_address_type_t gap_random_address_get_mode(void){ 4235 return gap_random_adress_type; 4236 } 4237 4238 void gap_random_address_set_update_period(int period_ms){ 4239 gap_random_adress_update_period = period_ms; 4240 if (!gap_random_address_type_requires_updates()) return; 4241 gap_random_address_update_stop(); 4242 gap_random_address_update_start(); 4243 } 4244 4245 void gap_random_address_set(bd_addr_t addr){ 4246 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4247 memcpy(sm_random_address, addr, 6); 4248 rau_state = RAU_SET_ADDRESS; 4249 sm_run(); 4250 } 4251 4252 #ifdef ENABLE_LE_PERIPHERAL 4253 /* 4254 * @brief Set Advertisement Paramters 4255 * @param adv_int_min 4256 * @param adv_int_max 4257 * @param adv_type 4258 * @param direct_address_type 4259 * @param direct_address 4260 * @param channel_map 4261 * @param filter_policy 4262 * 4263 * @note own_address_type is used from gap_random_address_set_mode 4264 */ 4265 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4266 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4267 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4268 direct_address_typ, direct_address, channel_map, filter_policy); 4269 } 4270 #endif 4271 4272 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4273 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4274 // wrong connection 4275 if (!sm_conn) return 0; 4276 // already encrypted 4277 if (sm_conn->sm_connection_encrypted) return 0; 4278 // only central can re-encrypt 4279 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4280 // irk status? 4281 switch(sm_conn->sm_irk_lookup_state){ 4282 case IRK_LOOKUP_FAILED: 4283 // done, cannot setup encryption 4284 return 0; 4285 case IRK_LOOKUP_SUCCEEDED: 4286 break; 4287 default: 4288 // IR Lookup pending 4289 return 1; 4290 } 4291 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4292 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4293 } 4294