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, (void *)(uintptr_t) sm_conn->sm_handle); 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, (void *)(uintptr_t) sm_conn->sm_handle); 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 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1689 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1690 if (sm_conn == NULL) return; 1691 1692 log_info("dhkey"); 1693 log_info_hexdump(&setup->sm_dhkey[0], 32); 1694 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1695 // trigger next step 1696 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1697 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1698 } 1699 sm_run(); 1700 } 1701 1702 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1703 // calculate DHKCheck 1704 sm_key56_t bd_addr_master, bd_addr_slave; 1705 bd_addr_master[0] = setup->sm_m_addr_type; 1706 bd_addr_slave[0] = setup->sm_s_addr_type; 1707 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1708 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1709 uint8_t iocap_a[3]; 1710 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1711 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1712 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1713 uint8_t iocap_b[3]; 1714 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1715 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1716 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1717 if (IS_RESPONDER(sm_conn->sm_role)){ 1718 // responder 1719 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); 1720 } else { 1721 // initiator 1722 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); 1723 } 1724 } 1725 1726 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1727 // validate E = f6() 1728 sm_key56_t bd_addr_master, bd_addr_slave; 1729 bd_addr_master[0] = setup->sm_m_addr_type; 1730 bd_addr_slave[0] = setup->sm_s_addr_type; 1731 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1732 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1733 1734 uint8_t iocap_a[3]; 1735 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1736 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1737 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1738 uint8_t iocap_b[3]; 1739 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1740 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1741 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1742 if (IS_RESPONDER(sm_conn->sm_role)){ 1743 // responder 1744 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); 1745 } else { 1746 // initiator 1747 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); 1748 } 1749 } 1750 1751 1752 // 1753 // Link Key Conversion Function h6 1754 // 1755 // h6(W, keyID) = AES-CMACW(keyID) 1756 // - W is 128 bits 1757 // - keyID is 32 bits 1758 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1759 const uint16_t message_len = 4; 1760 sm_cmac_connection = sm_conn; 1761 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1762 log_info("h6 key"); 1763 log_info_hexdump(w, 16); 1764 log_info("h6 message"); 1765 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1766 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1767 } 1768 1769 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1770 // Errata Service Release to the Bluetooth Specification: ESR09 1771 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1772 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1773 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1774 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1775 } 1776 1777 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1778 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1779 } 1780 1781 #endif 1782 1783 // key management legacy connections: 1784 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1785 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1786 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1787 // - responder reconnects: responder uses LTK receveived from master 1788 1789 // key management secure connections: 1790 // - both devices store same LTK from ECDH key exchange. 1791 1792 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1793 static void sm_load_security_info(sm_connection_t * sm_connection){ 1794 int encryption_key_size; 1795 int authenticated; 1796 int authorized; 1797 int secure_connection; 1798 1799 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1800 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1801 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1802 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); 1803 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1804 sm_connection->sm_connection_authenticated = authenticated; 1805 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1806 sm_connection->sm_connection_sc = secure_connection; 1807 } 1808 #endif 1809 1810 #ifdef ENABLE_LE_PERIPHERAL 1811 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1812 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1813 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1814 // re-establish used key encryption size 1815 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1816 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1817 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1818 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1819 // Legacy paring -> not SC 1820 sm_connection->sm_connection_sc = 0; 1821 log_info("sm: received ltk request with key size %u, authenticated %u", 1822 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1823 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1824 sm_run(); 1825 } 1826 #endif 1827 1828 static void sm_run(void){ 1829 1830 btstack_linked_list_iterator_t it; 1831 1832 // assert that stack has already bootet 1833 if (hci_get_state() != HCI_STATE_WORKING) return; 1834 1835 // assert that we can send at least commands 1836 if (!hci_can_send_command_packet_now()) return; 1837 1838 // pause until IR/ER are ready 1839 if (sm_persistent_keys_random_active) return; 1840 1841 // 1842 // non-connection related behaviour 1843 // 1844 1845 // distributed key generation 1846 switch (dkg_state){ 1847 case DKG_CALC_IRK: 1848 // already busy? 1849 if (sm_aes128_state == SM_AES128_IDLE) { 1850 log_info("DKG_CALC_IRK started"); 1851 // IRK = d1(IR, 1, 0) 1852 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1853 sm_aes128_state = SM_AES128_ACTIVE; 1854 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1855 return; 1856 } 1857 break; 1858 case DKG_CALC_DHK: 1859 // already busy? 1860 if (sm_aes128_state == SM_AES128_IDLE) { 1861 log_info("DKG_CALC_DHK started"); 1862 // DHK = d1(IR, 3, 0) 1863 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1864 sm_aes128_state = SM_AES128_ACTIVE; 1865 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1866 return; 1867 } 1868 break; 1869 default: 1870 break; 1871 } 1872 1873 // random address updates 1874 switch (rau_state){ 1875 case RAU_GET_RANDOM: 1876 rau_state = RAU_W4_RANDOM; 1877 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1878 return; 1879 case RAU_GET_ENC: 1880 // already busy? 1881 if (sm_aes128_state == SM_AES128_IDLE) { 1882 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1883 sm_aes128_state = SM_AES128_ACTIVE; 1884 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1885 return; 1886 } 1887 break; 1888 case RAU_SET_ADDRESS: 1889 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1890 rau_state = RAU_IDLE; 1891 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1892 return; 1893 default: 1894 break; 1895 } 1896 1897 // CSRK Lookup 1898 // -- if csrk lookup ready, find connection that require csrk lookup 1899 if (sm_address_resolution_idle()){ 1900 hci_connections_get_iterator(&it); 1901 while(btstack_linked_list_iterator_has_next(&it)){ 1902 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1903 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1904 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1905 // and start lookup 1906 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); 1907 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1908 break; 1909 } 1910 } 1911 } 1912 1913 // -- if csrk lookup ready, resolved addresses for received addresses 1914 if (sm_address_resolution_idle()) { 1915 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1916 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1917 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1918 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1919 btstack_memory_sm_lookup_entry_free(entry); 1920 } 1921 } 1922 1923 // -- Continue with CSRK device lookup by public or resolvable private address 1924 if (!sm_address_resolution_idle()){ 1925 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1926 while (sm_address_resolution_test < le_device_db_max_count()){ 1927 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1928 bd_addr_t addr; 1929 sm_key_t irk; 1930 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1931 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1932 1933 // skip unused entries 1934 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1935 sm_address_resolution_test++; 1936 continue; 1937 } 1938 1939 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1940 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1941 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1942 break; 1943 } 1944 1945 // if connection type is public, it must be a different one 1946 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1947 sm_address_resolution_test++; 1948 continue; 1949 } 1950 1951 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1952 1953 log_info("LE Device Lookup: calculate AH"); 1954 log_info_key("IRK", irk); 1955 1956 memcpy(sm_aes128_key, irk, 16); 1957 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1958 sm_address_resolution_ah_calculation_active = 1; 1959 sm_aes128_state = SM_AES128_ACTIVE; 1960 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1961 return; 1962 } 1963 1964 if (sm_address_resolution_test >= le_device_db_max_count()){ 1965 log_info("LE Device Lookup: not found"); 1966 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1967 } 1968 } 1969 1970 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1971 switch (sm_sc_oob_state){ 1972 case SM_SC_OOB_W2_CALC_CONFIRM: 1973 if (!sm_cmac_ready()) break; 1974 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1975 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1976 return; 1977 default: 1978 break; 1979 } 1980 #endif 1981 1982 // assert that we can send at least commands - cmd might have been sent by crypto engine 1983 if (!hci_can_send_command_packet_now()) return; 1984 1985 // handle basic actions that don't requires the full context 1986 hci_connections_get_iterator(&it); 1987 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1988 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1989 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1990 switch(sm_connection->sm_engine_state){ 1991 // responder side 1992 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1993 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1994 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1995 return; 1996 1997 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1998 case SM_SC_RECEIVED_LTK_REQUEST: 1999 switch (sm_connection->sm_irk_lookup_state){ 2000 case IRK_LOOKUP_FAILED: 2001 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2002 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2003 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2004 return; 2005 default: 2006 break; 2007 } 2008 break; 2009 #endif 2010 default: 2011 break; 2012 } 2013 } 2014 2015 // 2016 // active connection handling 2017 // -- use loop to handle next connection if lock on setup context is released 2018 2019 while (1) { 2020 2021 // Find connections that requires setup context and make active if no other is locked 2022 hci_connections_get_iterator(&it); 2023 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2024 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2025 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2026 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2027 int done = 1; 2028 int err; 2029 UNUSED(err); 2030 2031 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2032 // assert ec key is ready 2033 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2034 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2035 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2036 sm_ec_generate_new_key(); 2037 } 2038 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2039 continue; 2040 } 2041 } 2042 #endif 2043 2044 switch (sm_connection->sm_engine_state) { 2045 #ifdef ENABLE_LE_PERIPHERAL 2046 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2047 // send packet if possible, 2048 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2049 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2050 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2051 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2052 } else { 2053 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2054 } 2055 // don't lock sxetup context yet 2056 done = 0; 2057 break; 2058 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2059 sm_reset_setup(); 2060 sm_init_setup(sm_connection); 2061 // recover pairing request 2062 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2063 err = sm_stk_generation_init(sm_connection); 2064 2065 #ifdef ENABLE_TESTING_SUPPORT 2066 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2067 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2068 err = test_pairing_failure; 2069 } 2070 #endif 2071 if (err){ 2072 setup->sm_pairing_failed_reason = err; 2073 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2074 break; 2075 } 2076 sm_timeout_start(sm_connection); 2077 // generate random number first, if we need to show passkey 2078 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2079 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_connection->sm_handle); 2080 break; 2081 } 2082 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2083 break; 2084 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2085 sm_reset_setup(); 2086 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2087 break; 2088 2089 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2090 case SM_SC_RECEIVED_LTK_REQUEST: 2091 switch (sm_connection->sm_irk_lookup_state){ 2092 case IRK_LOOKUP_SUCCEEDED: 2093 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2094 // start using context by loading security info 2095 sm_reset_setup(); 2096 sm_load_security_info(sm_connection); 2097 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2098 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2099 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2100 break; 2101 } 2102 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2103 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2104 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2105 // don't lock setup context yet 2106 return; 2107 default: 2108 // just wait until IRK lookup is completed 2109 // don't lock setup context yet 2110 done = 0; 2111 break; 2112 } 2113 break; 2114 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2115 #endif /* ENABLE_LE_PERIPHERAL */ 2116 2117 #ifdef ENABLE_LE_CENTRAL 2118 case SM_INITIATOR_PH0_HAS_LTK: 2119 sm_reset_setup(); 2120 sm_load_security_info(sm_connection); 2121 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2122 break; 2123 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2124 sm_reset_setup(); 2125 sm_init_setup(sm_connection); 2126 sm_timeout_start(sm_connection); 2127 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2128 break; 2129 #endif 2130 2131 default: 2132 done = 0; 2133 break; 2134 } 2135 if (done){ 2136 sm_active_connection_handle = sm_connection->sm_handle; 2137 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); 2138 } 2139 } 2140 2141 // 2142 // active connection handling 2143 // 2144 2145 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2146 2147 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2148 if (!connection) { 2149 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2150 return; 2151 } 2152 2153 // assert that we could send a SM PDU - not needed for all of the following 2154 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2155 log_info("cannot send now, requesting can send now event"); 2156 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2157 return; 2158 } 2159 2160 // send keypress notifications 2161 if (setup->sm_keypress_notification){ 2162 int i; 2163 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2164 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2165 uint8_t action = 0; 2166 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2167 if (flags & (1<<i)){ 2168 int clear_flag = 1; 2169 switch (i){ 2170 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2171 case SM_KEYPRESS_PASSKEY_CLEARED: 2172 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2173 default: 2174 break; 2175 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2176 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2177 num_actions--; 2178 clear_flag = num_actions == 0; 2179 break; 2180 } 2181 if (clear_flag){ 2182 flags &= ~(1<<i); 2183 } 2184 action = i; 2185 break; 2186 } 2187 } 2188 setup->sm_keypress_notification = (num_actions << 5) | flags; 2189 2190 // send keypress notification 2191 uint8_t buffer[2]; 2192 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2193 buffer[1] = action; 2194 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2195 2196 // try 2197 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2198 return; 2199 } 2200 2201 int key_distribution_flags; 2202 UNUSED(key_distribution_flags); 2203 2204 log_info("sm_run: state %u", connection->sm_engine_state); 2205 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2206 log_info("sm_run // cannot send"); 2207 } 2208 switch (connection->sm_engine_state){ 2209 2210 // general 2211 case SM_GENERAL_SEND_PAIRING_FAILED: { 2212 uint8_t buffer[2]; 2213 buffer[0] = SM_CODE_PAIRING_FAILED; 2214 buffer[1] = setup->sm_pairing_failed_reason; 2215 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2216 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2217 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2218 sm_done_for_handle(connection->sm_handle); 2219 break; 2220 } 2221 2222 // responding state 2223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2224 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2225 if (!sm_cmac_ready()) break; 2226 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2227 sm_sc_calculate_local_confirm(connection); 2228 break; 2229 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2230 if (!sm_cmac_ready()) break; 2231 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2232 sm_sc_calculate_remote_confirm(connection); 2233 break; 2234 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2235 if (!sm_cmac_ready()) break; 2236 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2237 sm_sc_calculate_f6_for_dhkey_check(connection); 2238 break; 2239 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2240 if (!sm_cmac_ready()) break; 2241 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2242 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2243 break; 2244 case SM_SC_W2_CALCULATE_F5_SALT: 2245 if (!sm_cmac_ready()) break; 2246 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2247 f5_calculate_salt(connection); 2248 break; 2249 case SM_SC_W2_CALCULATE_F5_MACKEY: 2250 if (!sm_cmac_ready()) break; 2251 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2252 f5_calculate_mackey(connection); 2253 break; 2254 case SM_SC_W2_CALCULATE_F5_LTK: 2255 if (!sm_cmac_ready()) break; 2256 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2257 f5_calculate_ltk(connection); 2258 break; 2259 case SM_SC_W2_CALCULATE_G2: 2260 if (!sm_cmac_ready()) break; 2261 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2262 g2_calculate(connection); 2263 break; 2264 case SM_SC_W2_CALCULATE_H6_ILK: 2265 if (!sm_cmac_ready()) break; 2266 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2267 h6_calculate_ilk(connection); 2268 break; 2269 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2270 if (!sm_cmac_ready()) break; 2271 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2272 h6_calculate_br_edr_link_key(connection); 2273 break; 2274 #endif 2275 2276 #ifdef ENABLE_LE_CENTRAL 2277 // initiator side 2278 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2279 sm_key_t peer_ltk_flipped; 2280 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2281 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2282 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2283 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2284 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2285 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2286 return; 2287 } 2288 2289 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2290 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2291 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2292 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2293 sm_timeout_reset(connection); 2294 break; 2295 #endif 2296 2297 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2298 2299 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2300 int trigger_user_response = 0; 2301 2302 uint8_t buffer[65]; 2303 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2304 // 2305 reverse_256(&ec_q[0], &buffer[1]); 2306 reverse_256(&ec_q[32], &buffer[33]); 2307 2308 #ifdef ENABLE_TESTING_SUPPORT 2309 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2310 log_info("testing_support: invalidating public key"); 2311 // flip single bit of public key coordinate 2312 buffer[1] ^= 1; 2313 } 2314 #endif 2315 2316 // stk generation method 2317 // passkey entry: notify app to show passkey or to request passkey 2318 switch (setup->sm_stk_generation_method){ 2319 case JUST_WORKS: 2320 case NUMERIC_COMPARISON: 2321 if (IS_RESPONDER(connection->sm_role)){ 2322 // responder 2323 sm_sc_start_calculating_local_confirm(connection); 2324 } else { 2325 // initiator 2326 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2327 } 2328 break; 2329 case PK_INIT_INPUT: 2330 case PK_RESP_INPUT: 2331 case PK_BOTH_INPUT: 2332 // use random TK for display 2333 memcpy(setup->sm_ra, setup->sm_tk, 16); 2334 memcpy(setup->sm_rb, setup->sm_tk, 16); 2335 setup->sm_passkey_bit = 0; 2336 2337 if (IS_RESPONDER(connection->sm_role)){ 2338 // responder 2339 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2340 } else { 2341 // initiator 2342 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2343 } 2344 trigger_user_response = 1; 2345 break; 2346 case OOB: 2347 if (IS_RESPONDER(connection->sm_role)){ 2348 // responder 2349 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2350 } else { 2351 // initiator 2352 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2353 } 2354 break; 2355 } 2356 2357 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2358 sm_timeout_reset(connection); 2359 2360 // trigger user response after sending pdu 2361 if (trigger_user_response){ 2362 sm_trigger_user_response(connection); 2363 } 2364 break; 2365 } 2366 case SM_SC_SEND_CONFIRMATION: { 2367 uint8_t buffer[17]; 2368 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2369 reverse_128(setup->sm_local_confirm, &buffer[1]); 2370 if (IS_RESPONDER(connection->sm_role)){ 2371 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2372 } else { 2373 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2374 } 2375 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2376 sm_timeout_reset(connection); 2377 break; 2378 } 2379 case SM_SC_SEND_PAIRING_RANDOM: { 2380 uint8_t buffer[17]; 2381 buffer[0] = SM_CODE_PAIRING_RANDOM; 2382 reverse_128(setup->sm_local_nonce, &buffer[1]); 2383 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2384 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2385 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2386 if (IS_RESPONDER(connection->sm_role)){ 2387 // responder 2388 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2389 } else { 2390 // initiator 2391 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2392 } 2393 } else { 2394 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2395 if (IS_RESPONDER(connection->sm_role)){ 2396 // responder 2397 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2398 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2399 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2400 } else { 2401 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2402 sm_sc_prepare_dhkey_check(connection); 2403 } 2404 } else { 2405 // initiator 2406 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2407 } 2408 } 2409 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2410 sm_timeout_reset(connection); 2411 break; 2412 } 2413 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2414 uint8_t buffer[17]; 2415 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2416 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2417 2418 if (IS_RESPONDER(connection->sm_role)){ 2419 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2420 } else { 2421 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2422 } 2423 2424 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2425 sm_timeout_reset(connection); 2426 break; 2427 } 2428 2429 #endif 2430 2431 #ifdef ENABLE_LE_PERIPHERAL 2432 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2433 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2434 2435 // start with initiator key dist flags 2436 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2437 2438 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2439 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2440 if (setup->sm_use_secure_connections){ 2441 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2442 } 2443 #endif 2444 // setup in response 2445 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); 2446 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); 2447 2448 // update key distribution after ENC was dropped 2449 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2450 2451 if (setup->sm_use_secure_connections){ 2452 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2453 } else { 2454 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2455 } 2456 2457 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2458 sm_timeout_reset(connection); 2459 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2460 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2461 sm_trigger_user_response(connection); 2462 } 2463 return; 2464 #endif 2465 2466 case SM_PH2_SEND_PAIRING_RANDOM: { 2467 uint8_t buffer[17]; 2468 buffer[0] = SM_CODE_PAIRING_RANDOM; 2469 reverse_128(setup->sm_local_random, &buffer[1]); 2470 if (IS_RESPONDER(connection->sm_role)){ 2471 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2472 } else { 2473 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2474 } 2475 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2476 sm_timeout_reset(connection); 2477 break; 2478 } 2479 2480 case SM_PH2_C1_GET_ENC_A: 2481 // already busy? 2482 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2483 // calculate confirm using aes128 engine - step 1 2484 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); 2485 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2486 sm_aes128_state = SM_AES128_ACTIVE; 2487 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, (void *)(uintptr_t) connection->sm_handle); 2488 break; 2489 2490 case SM_PH2_C1_GET_ENC_C: 2491 // already busy? 2492 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2493 // calculate m_confirm using aes128 engine - step 1 2494 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); 2495 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2496 sm_aes128_state = SM_AES128_ACTIVE; 2497 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, (void *)(uintptr_t) connection->sm_handle); 2498 break; 2499 2500 case SM_PH2_CALC_STK: 2501 // already busy? 2502 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2503 // calculate STK 2504 if (IS_RESPONDER(connection->sm_role)){ 2505 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2506 } else { 2507 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2508 } 2509 connection->sm_engine_state = SM_PH2_W4_STK; 2510 sm_aes128_state = SM_AES128_ACTIVE; 2511 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2512 break; 2513 2514 case SM_PH3_Y_GET_ENC: 2515 // already busy? 2516 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2517 // PH3B2 - calculate Y from - enc 2518 // Y = dm(DHK, Rand) 2519 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2520 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2521 sm_aes128_state = SM_AES128_ACTIVE; 2522 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, (void *)(uintptr_t) connection->sm_handle); 2523 break; 2524 2525 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2526 uint8_t buffer[17]; 2527 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2528 reverse_128(setup->sm_local_confirm, &buffer[1]); 2529 if (IS_RESPONDER(connection->sm_role)){ 2530 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2531 } else { 2532 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2533 } 2534 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2535 sm_timeout_reset(connection); 2536 return; 2537 } 2538 #ifdef ENABLE_LE_PERIPHERAL 2539 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2540 sm_key_t stk_flipped; 2541 reverse_128(setup->sm_ltk, stk_flipped); 2542 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2543 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2544 return; 2545 } 2546 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2547 sm_key_t ltk_flipped; 2548 reverse_128(setup->sm_ltk, ltk_flipped); 2549 connection->sm_engine_state = SM_RESPONDER_IDLE; 2550 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2551 sm_done_for_handle(connection->sm_handle); 2552 return; 2553 } 2554 case SM_RESPONDER_PH4_Y_GET_ENC: 2555 // already busy? 2556 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2557 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2558 // Y = dm(DHK, Rand) 2559 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2560 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2561 sm_aes128_state = SM_AES128_ACTIVE; 2562 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, (void *)(uintptr_t) connection->sm_handle); 2563 return; 2564 #endif 2565 #ifdef ENABLE_LE_CENTRAL 2566 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2567 sm_key_t stk_flipped; 2568 reverse_128(setup->sm_ltk, stk_flipped); 2569 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2570 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2571 return; 2572 } 2573 #endif 2574 2575 case SM_PH3_DISTRIBUTE_KEYS: 2576 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2577 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2578 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2579 uint8_t buffer[17]; 2580 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2581 reverse_128(setup->sm_ltk, &buffer[1]); 2582 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2583 sm_timeout_reset(connection); 2584 return; 2585 } 2586 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2587 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2588 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2589 uint8_t buffer[11]; 2590 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2591 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2592 reverse_64(setup->sm_local_rand, &buffer[3]); 2593 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2594 sm_timeout_reset(connection); 2595 return; 2596 } 2597 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2598 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2599 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2600 uint8_t buffer[17]; 2601 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2602 reverse_128(sm_persistent_irk, &buffer[1]); 2603 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2604 sm_timeout_reset(connection); 2605 return; 2606 } 2607 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2608 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2609 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2610 bd_addr_t local_address; 2611 uint8_t buffer[8]; 2612 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2613 switch (gap_random_address_get_mode()){ 2614 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2615 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2616 // public or static random 2617 gap_le_get_own_address(&buffer[1], local_address); 2618 break; 2619 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2620 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2621 // fallback to public 2622 gap_local_bd_addr(local_address); 2623 buffer[1] = 0; 2624 break; 2625 } 2626 reverse_bd_addr(local_address, &buffer[2]); 2627 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2628 sm_timeout_reset(connection); 2629 return; 2630 } 2631 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2632 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2633 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2634 2635 #ifdef ENABLE_LE_SIGNED_WRITE 2636 // hack to reproduce test runs 2637 if (test_use_fixed_local_csrk){ 2638 memset(setup->sm_local_csrk, 0xcc, 16); 2639 } 2640 2641 // store local CSRK 2642 if (setup->sm_le_device_index >= 0){ 2643 log_info("sm: store local CSRK"); 2644 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2645 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2646 } 2647 #endif 2648 2649 uint8_t buffer[17]; 2650 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2651 reverse_128(setup->sm_local_csrk, &buffer[1]); 2652 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2653 sm_timeout_reset(connection); 2654 return; 2655 } 2656 2657 // keys are sent 2658 if (IS_RESPONDER(connection->sm_role)){ 2659 // slave -> receive master keys if any 2660 if (sm_key_distribution_all_received(connection)){ 2661 sm_key_distribution_handle_all_received(connection); 2662 connection->sm_engine_state = SM_RESPONDER_IDLE; 2663 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2664 sm_done_for_handle(connection->sm_handle); 2665 } else { 2666 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2667 } 2668 } else { 2669 // master -> all done 2670 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2671 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2672 sm_done_for_handle(connection->sm_handle); 2673 } 2674 break; 2675 2676 default: 2677 break; 2678 } 2679 2680 // check again if active connection was released 2681 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2682 } 2683 } 2684 2685 // sm_aes128_state stays active 2686 static void sm_handle_encryption_result_enc_a(void *arg){ 2687 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2688 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2689 if (connection == NULL) return; 2690 2691 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2692 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, (void *)(uintptr_t) connection->sm_handle); 2693 } 2694 2695 static void sm_handle_encryption_result_enc_b(void *arg){ 2696 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2697 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2698 if (connection == NULL) return; 2699 2700 sm_aes128_state = SM_AES128_IDLE; 2701 log_info_key("c1!", setup->sm_local_confirm); 2702 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2703 sm_run(); 2704 } 2705 2706 // sm_aes128_state stays active 2707 static void sm_handle_encryption_result_enc_c(void *arg){ 2708 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2709 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2710 if (connection == NULL) return; 2711 2712 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2713 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, (void *)(uintptr_t) connection->sm_handle); 2714 } 2715 2716 static void sm_handle_encryption_result_enc_d(void * arg){ 2717 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2718 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2719 if (connection == NULL) return; 2720 2721 sm_aes128_state = SM_AES128_IDLE; 2722 log_info_key("c1!", sm_aes128_ciphertext); 2723 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2724 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2725 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2726 sm_run(); 2727 return; 2728 } 2729 if (IS_RESPONDER(connection->sm_role)){ 2730 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2731 sm_run(); 2732 } else { 2733 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2734 sm_aes128_state = SM_AES128_ACTIVE; 2735 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2736 } 2737 } 2738 2739 static void sm_handle_encryption_result_enc_stk(void *arg){ 2740 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2741 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2742 if (connection == NULL) return; 2743 2744 sm_aes128_state = SM_AES128_IDLE; 2745 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2746 log_info_key("stk", setup->sm_ltk); 2747 if (IS_RESPONDER(connection->sm_role)){ 2748 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2749 } else { 2750 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2751 } 2752 sm_run(); 2753 } 2754 2755 // sm_aes128_state stays active 2756 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2757 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2758 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2759 if (connection == NULL) return; 2760 2761 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2762 log_info_hex16("y", setup->sm_local_y); 2763 // PH3B3 - calculate EDIV 2764 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2765 log_info_hex16("ediv", setup->sm_local_ediv); 2766 // PH3B4 - calculate LTK - enc 2767 // LTK = d1(ER, DIV, 0)) 2768 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2769 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); 2770 } 2771 2772 #ifdef ENABLE_LE_PERIPHERAL 2773 // sm_aes128_state stays active 2774 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2775 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2776 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2777 if (connection == NULL) return; 2778 2779 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2780 log_info_hex16("y", setup->sm_local_y); 2781 2782 // PH3B3 - calculate DIV 2783 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2784 log_info_hex16("ediv", setup->sm_local_ediv); 2785 // PH3B4 - calculate LTK - enc 2786 // LTK = d1(ER, DIV, 0)) 2787 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2788 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, (void *)(uintptr_t) connection->sm_handle); 2789 } 2790 #endif 2791 2792 // sm_aes128_state stays active 2793 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2794 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2795 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2796 if (connection == NULL) return; 2797 2798 log_info_key("ltk", setup->sm_ltk); 2799 // calc CSRK next 2800 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2801 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); 2802 } 2803 2804 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2805 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2806 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2807 if (connection == NULL) return; 2808 2809 sm_aes128_state = SM_AES128_IDLE; 2810 log_info_key("csrk", setup->sm_local_csrk); 2811 if (setup->sm_key_distribution_send_set){ 2812 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2813 } else { 2814 // no keys to send, just continue 2815 if (IS_RESPONDER(connection->sm_role)){ 2816 // slave -> receive master keys 2817 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2818 } else { 2819 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2820 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2821 } else { 2822 // master -> all done 2823 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2824 sm_done_for_handle(connection->sm_handle); 2825 } 2826 } 2827 } 2828 sm_run(); 2829 } 2830 2831 #ifdef ENABLE_LE_PERIPHERAL 2832 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2833 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2834 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2835 if (connection == NULL) return; 2836 2837 sm_aes128_state = SM_AES128_IDLE; 2838 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2839 log_info_key("ltk", setup->sm_ltk); 2840 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2841 sm_run(); 2842 } 2843 #endif 2844 2845 static void sm_handle_encryption_result_address_resolution(void *arg){ 2846 UNUSED(arg); 2847 sm_aes128_state = SM_AES128_IDLE; 2848 sm_address_resolution_ah_calculation_active = 0; 2849 // compare calulated address against connecting device 2850 uint8_t * hash = &sm_aes128_ciphertext[13]; 2851 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2852 log_info("LE Device Lookup: matched resolvable private address"); 2853 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2854 sm_run(); 2855 return; 2856 } 2857 // no match, try next 2858 sm_address_resolution_test++; 2859 sm_run(); 2860 } 2861 2862 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2863 UNUSED(arg); 2864 sm_aes128_state = SM_AES128_IDLE; 2865 log_info_key("irk", sm_persistent_irk); 2866 dkg_state = DKG_CALC_DHK; 2867 sm_run(); 2868 } 2869 2870 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2871 UNUSED(arg); 2872 sm_aes128_state = SM_AES128_IDLE; 2873 log_info_key("dhk", sm_persistent_dhk); 2874 dkg_state = DKG_READY; 2875 sm_run(); 2876 } 2877 2878 static void sm_handle_encryption_result_rau(void *arg){ 2879 UNUSED(arg); 2880 sm_aes128_state = SM_AES128_IDLE; 2881 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2882 rau_state = RAU_SET_ADDRESS; 2883 sm_run(); 2884 } 2885 2886 static void sm_handle_random_result_rau(void * arg){ 2887 UNUSED(arg); 2888 // non-resolvable vs. resolvable 2889 switch (gap_random_adress_type){ 2890 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2891 // resolvable: use random as prand and calc address hash 2892 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2893 sm_random_address[0] &= 0x3f; 2894 sm_random_address[0] |= 0x40; 2895 rau_state = RAU_GET_ENC; 2896 break; 2897 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2898 default: 2899 // "The two most significant bits of the address shall be equal to ‘0’"" 2900 sm_random_address[0] &= 0x3f; 2901 rau_state = RAU_SET_ADDRESS; 2902 break; 2903 } 2904 sm_run(); 2905 } 2906 2907 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2908 static void sm_handle_random_result_sc_get_random(void * arg){ 2909 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2910 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2911 if (connection == NULL) return; 2912 2913 // OOB 2914 if (setup->sm_stk_generation_method == OOB){ 2915 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2916 sm_run(); 2917 return; 2918 } 2919 2920 // initiator & jw/nc -> send pairing random 2921 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2922 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2923 } else { 2924 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2925 } 2926 sm_run(); 2927 } 2928 #endif 2929 2930 static void sm_handle_random_result_ph2_random(void * arg){ 2931 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2932 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2933 if (connection == NULL) return; 2934 2935 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2936 sm_run(); 2937 } 2938 2939 static void sm_handle_random_result_ph2_tk(void * arg){ 2940 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2941 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2942 if (connection == NULL) return; 2943 2944 sm_reset_tk(); 2945 uint32_t tk; 2946 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2947 // map random to 0-999999 without speding much cycles on a modulus operation 2948 tk = little_endian_read_32(sm_random_data,0); 2949 tk = tk & 0xfffff; // 1048575 2950 if (tk >= 999999){ 2951 tk = tk - 999999; 2952 } 2953 } else { 2954 // override with pre-defined passkey 2955 tk = sm_fixed_passkey_in_display_role; 2956 } 2957 big_endian_store_32(setup->sm_tk, 12, tk); 2958 if (IS_RESPONDER(connection->sm_role)){ 2959 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2960 } else { 2961 if (setup->sm_use_secure_connections){ 2962 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2963 } else { 2964 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2965 sm_trigger_user_response(connection); 2966 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2967 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2968 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) connection->sm_handle); 2969 } 2970 } 2971 } 2972 sm_run(); 2973 } 2974 2975 static void sm_handle_random_result_ph3_div(void * arg){ 2976 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2977 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2978 if (connection == NULL) return; 2979 2980 // use 16 bit from random value as div 2981 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2982 log_info_hex16("div", setup->sm_local_div); 2983 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2984 sm_run(); 2985 } 2986 2987 static void sm_handle_random_result_ph3_random(void * arg){ 2988 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2989 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2990 if (connection == NULL) return; 2991 2992 reverse_64(sm_random_data, setup->sm_local_rand); 2993 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2994 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2995 // no db for authenticated flag hack: store flag in bit 4 of LSB 2996 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2997 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 2998 } 2999 static void sm_validate_er_ir(void){ 3000 // warn about default ER/IR 3001 int warning = 0; 3002 if (sm_ir_is_default()){ 3003 warning = 1; 3004 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3005 } 3006 if (sm_er_is_default()){ 3007 warning = 1; 3008 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3009 } 3010 if (warning) { 3011 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3012 } 3013 } 3014 3015 static void sm_handle_random_result_ir(void *arg){ 3016 sm_persistent_keys_random_active = 0; 3017 if (arg){ 3018 // key generated, store in tlv 3019 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3020 log_info("Generated IR key. Store in TLV status: %d", status); 3021 } 3022 log_info_key("IR", sm_persistent_ir); 3023 dkg_state = DKG_CALC_IRK; 3024 sm_run(); 3025 } 3026 3027 static void sm_handle_random_result_er(void *arg){ 3028 sm_persistent_keys_random_active = 0; 3029 if (arg){ 3030 // key generated, store in tlv 3031 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3032 log_info("Generated ER key. Store in TLV status: %d", status); 3033 } 3034 log_info_key("ER", sm_persistent_er); 3035 3036 // try load ir 3037 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3038 if (key_size == 16){ 3039 // ok, let's continue 3040 log_info("IR from TLV"); 3041 sm_handle_random_result_ir( NULL ); 3042 } else { 3043 // invalid, generate new random one 3044 sm_persistent_keys_random_active = 1; 3045 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3046 } 3047 } 3048 3049 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3050 3051 UNUSED(channel); // ok: there is no channel 3052 UNUSED(size); // ok: fixed format HCI events 3053 3054 sm_connection_t * sm_conn; 3055 hci_con_handle_t con_handle; 3056 3057 switch (packet_type) { 3058 3059 case HCI_EVENT_PACKET: 3060 switch (hci_event_packet_get_type(packet)) { 3061 3062 case BTSTACK_EVENT_STATE: 3063 // bt stack activated, get started 3064 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3065 log_info("HCI Working!"); 3066 3067 // setup IR/ER with TLV 3068 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3069 if (sm_tlv_impl){ 3070 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3071 if (key_size == 16){ 3072 // ok, let's continue 3073 log_info("ER from TLV"); 3074 sm_handle_random_result_er( NULL ); 3075 } else { 3076 // invalid, generate random one 3077 sm_persistent_keys_random_active = 1; 3078 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3079 } 3080 } else { 3081 sm_validate_er_ir(); 3082 dkg_state = DKG_CALC_IRK; 3083 } 3084 } 3085 break; 3086 3087 case HCI_EVENT_LE_META: 3088 switch (packet[2]) { 3089 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3090 3091 log_info("sm: connected"); 3092 3093 if (packet[3]) return; // connection failed 3094 3095 con_handle = little_endian_read_16(packet, 4); 3096 sm_conn = sm_get_connection_for_handle(con_handle); 3097 if (!sm_conn) break; 3098 3099 sm_conn->sm_handle = con_handle; 3100 sm_conn->sm_role = packet[6]; 3101 sm_conn->sm_peer_addr_type = packet[7]; 3102 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3103 3104 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3105 3106 // reset security properties 3107 sm_conn->sm_connection_encrypted = 0; 3108 sm_conn->sm_connection_authenticated = 0; 3109 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3110 sm_conn->sm_le_db_index = -1; 3111 3112 // prepare CSRK lookup (does not involve setup) 3113 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3114 3115 // just connected -> everything else happens in sm_run() 3116 if (IS_RESPONDER(sm_conn->sm_role)){ 3117 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3118 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3119 if (sm_slave_request_security) { 3120 // request security if requested by app 3121 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3122 } else { 3123 // otherwise, wait for pairing request 3124 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3125 } 3126 } 3127 break; 3128 } else { 3129 // master 3130 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3131 } 3132 break; 3133 3134 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3135 con_handle = little_endian_read_16(packet, 3); 3136 sm_conn = sm_get_connection_for_handle(con_handle); 3137 if (!sm_conn) break; 3138 3139 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3140 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3141 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3142 break; 3143 } 3144 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3145 // PH2 SEND LTK as we need to exchange keys in PH3 3146 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3147 break; 3148 } 3149 3150 // store rand and ediv 3151 reverse_64(&packet[5], sm_conn->sm_local_rand); 3152 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3153 3154 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3155 // potentially stored LTK is from the master 3156 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3157 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3158 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3159 break; 3160 } 3161 // additionally check if remote is in LE Device DB if requested 3162 switch(sm_conn->sm_irk_lookup_state){ 3163 case IRK_LOOKUP_FAILED: 3164 log_info("LTK Request: device not in device db"); 3165 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3166 break; 3167 case IRK_LOOKUP_SUCCEEDED: 3168 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3169 break; 3170 default: 3171 // wait for irk look doen 3172 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3173 break; 3174 } 3175 break; 3176 } 3177 3178 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3179 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3180 #else 3181 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3182 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3183 #endif 3184 break; 3185 3186 default: 3187 break; 3188 } 3189 break; 3190 3191 case HCI_EVENT_ENCRYPTION_CHANGE: 3192 con_handle = little_endian_read_16(packet, 3); 3193 sm_conn = sm_get_connection_for_handle(con_handle); 3194 if (!sm_conn) break; 3195 3196 sm_conn->sm_connection_encrypted = packet[5]; 3197 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3198 sm_conn->sm_actual_encryption_key_size); 3199 log_info("event handler, state %u", sm_conn->sm_engine_state); 3200 3201 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3202 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3203 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3204 // notify client, if pairing was requested before 3205 if (sm_conn->sm_pairing_requested){ 3206 sm_conn->sm_pairing_requested = 0; 3207 if (sm_conn->sm_connection_encrypted){ 3208 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3209 } else { 3210 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3211 } 3212 } 3213 sm_done_for_handle(sm_conn->sm_handle); 3214 break; 3215 } 3216 3217 if (!sm_conn->sm_connection_encrypted) break; 3218 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3219 3220 // continue pairing 3221 switch (sm_conn->sm_engine_state){ 3222 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3223 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3224 sm_done_for_handle(sm_conn->sm_handle); 3225 break; 3226 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3227 if (IS_RESPONDER(sm_conn->sm_role)){ 3228 // slave 3229 if (setup->sm_use_secure_connections){ 3230 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3231 } else { 3232 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3233 } 3234 } else { 3235 // master 3236 if (sm_key_distribution_all_received(sm_conn)){ 3237 // skip receiving keys as there are none 3238 sm_key_distribution_handle_all_received(sm_conn); 3239 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3240 } else { 3241 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3242 } 3243 } 3244 break; 3245 default: 3246 break; 3247 } 3248 break; 3249 3250 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3251 con_handle = little_endian_read_16(packet, 3); 3252 sm_conn = sm_get_connection_for_handle(con_handle); 3253 if (!sm_conn) break; 3254 3255 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3256 log_info("event handler, state %u", sm_conn->sm_engine_state); 3257 // continue if part of initial pairing 3258 switch (sm_conn->sm_engine_state){ 3259 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3260 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3261 sm_done_for_handle(sm_conn->sm_handle); 3262 break; 3263 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3264 if (IS_RESPONDER(sm_conn->sm_role)){ 3265 // slave 3266 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3267 } else { 3268 // master 3269 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3270 } 3271 break; 3272 default: 3273 break; 3274 } 3275 break; 3276 3277 3278 case HCI_EVENT_DISCONNECTION_COMPLETE: 3279 con_handle = little_endian_read_16(packet, 3); 3280 sm_done_for_handle(con_handle); 3281 sm_conn = sm_get_connection_for_handle(con_handle); 3282 if (!sm_conn) break; 3283 3284 // delete stored bonding on disconnect with authentication failure in ph0 3285 if (sm_conn->sm_role == 0 3286 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3287 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3288 le_device_db_remove(sm_conn->sm_le_db_index); 3289 } 3290 3291 // pairing failed, if it was ongoing 3292 switch (sm_conn->sm_engine_state){ 3293 case SM_GENERAL_IDLE: 3294 case SM_INITIATOR_CONNECTED: 3295 case SM_RESPONDER_IDLE: 3296 break; 3297 default: 3298 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3299 break; 3300 } 3301 3302 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3303 sm_conn->sm_handle = 0; 3304 break; 3305 3306 case HCI_EVENT_COMMAND_COMPLETE: 3307 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3308 // set local addr for le device db 3309 bd_addr_t addr; 3310 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3311 le_device_db_set_local_bd_addr(addr); 3312 } 3313 break; 3314 default: 3315 break; 3316 } 3317 break; 3318 default: 3319 break; 3320 } 3321 3322 sm_run(); 3323 } 3324 3325 static inline int sm_calc_actual_encryption_key_size(int other){ 3326 if (other < sm_min_encryption_key_size) return 0; 3327 if (other < sm_max_encryption_key_size) return other; 3328 return sm_max_encryption_key_size; 3329 } 3330 3331 3332 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3333 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3334 switch (method){ 3335 case JUST_WORKS: 3336 case NUMERIC_COMPARISON: 3337 return 1; 3338 default: 3339 return 0; 3340 } 3341 } 3342 // responder 3343 3344 static int sm_passkey_used(stk_generation_method_t method){ 3345 switch (method){ 3346 case PK_RESP_INPUT: 3347 return 1; 3348 default: 3349 return 0; 3350 } 3351 } 3352 3353 static int sm_passkey_entry(stk_generation_method_t method){ 3354 switch (method){ 3355 case PK_RESP_INPUT: 3356 case PK_INIT_INPUT: 3357 case PK_BOTH_INPUT: 3358 return 1; 3359 default: 3360 return 0; 3361 } 3362 } 3363 3364 #endif 3365 3366 /** 3367 * @return ok 3368 */ 3369 static int sm_validate_stk_generation_method(void){ 3370 // check if STK generation method is acceptable by client 3371 switch (setup->sm_stk_generation_method){ 3372 case JUST_WORKS: 3373 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3374 case PK_RESP_INPUT: 3375 case PK_INIT_INPUT: 3376 case PK_BOTH_INPUT: 3377 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3378 case OOB: 3379 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3380 case NUMERIC_COMPARISON: 3381 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3382 default: 3383 return 0; 3384 } 3385 } 3386 3387 // size of complete sm_pdu used to validate input 3388 static const uint8_t sm_pdu_size[] = { 3389 0, // 0x00 invalid opcode 3390 7, // 0x01 pairing request 3391 7, // 0x02 pairing response 3392 17, // 0x03 pairing confirm 3393 17, // 0x04 pairing random 3394 2, // 0x05 pairing failed 3395 17, // 0x06 encryption information 3396 11, // 0x07 master identification 3397 17, // 0x08 identification information 3398 8, // 0x09 identify address information 3399 17, // 0x0a signing information 3400 2, // 0x0b security request 3401 65, // 0x0c pairing public key 3402 17, // 0x0d pairing dhk check 3403 2, // 0x0e keypress notification 3404 }; 3405 3406 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3407 3408 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3409 sm_run(); 3410 } 3411 3412 if (packet_type != SM_DATA_PACKET) return; 3413 if (size == 0) return; 3414 3415 uint8_t sm_pdu_code = packet[0]; 3416 3417 // validate pdu size 3418 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3419 if (sm_pdu_size[sm_pdu_code] != size) return; 3420 3421 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3422 if (!sm_conn) return; 3423 3424 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3425 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3426 sm_done_for_handle(con_handle); 3427 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3428 return; 3429 } 3430 3431 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3432 3433 int err; 3434 UNUSED(err); 3435 3436 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3437 uint8_t buffer[5]; 3438 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3439 buffer[1] = 3; 3440 little_endian_store_16(buffer, 2, con_handle); 3441 buffer[4] = packet[1]; 3442 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3443 return; 3444 } 3445 3446 switch (sm_conn->sm_engine_state){ 3447 3448 // a sm timeout requries a new physical connection 3449 case SM_GENERAL_TIMEOUT: 3450 return; 3451 3452 #ifdef ENABLE_LE_CENTRAL 3453 3454 // Initiator 3455 case SM_INITIATOR_CONNECTED: 3456 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3457 sm_pdu_received_in_wrong_state(sm_conn); 3458 break; 3459 } 3460 3461 // IRK complete? 3462 int have_ltk; 3463 uint8_t ltk[16]; 3464 switch (sm_conn->sm_irk_lookup_state){ 3465 case IRK_LOOKUP_FAILED: 3466 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3467 break; 3468 case IRK_LOOKUP_SUCCEEDED: 3469 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3470 have_ltk = !sm_is_null_key(ltk); 3471 log_info("central: security request - have_ltk %u", have_ltk); 3472 if (have_ltk){ 3473 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3474 } else { 3475 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3476 } 3477 break; 3478 default: 3479 break; 3480 } 3481 3482 // otherwise, store security request 3483 sm_conn->sm_security_request_received = 1; 3484 break; 3485 3486 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3487 // Core 5, Vol 3, Part H, 2.4.6: 3488 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3489 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3490 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3491 log_info("Ignoring Security Request"); 3492 break; 3493 } 3494 3495 // all other pdus are incorrect 3496 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3497 sm_pdu_received_in_wrong_state(sm_conn); 3498 break; 3499 } 3500 3501 // store pairing request 3502 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3503 err = sm_stk_generation_init(sm_conn); 3504 3505 #ifdef ENABLE_TESTING_SUPPORT 3506 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3507 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3508 err = test_pairing_failure; 3509 } 3510 #endif 3511 3512 if (err){ 3513 setup->sm_pairing_failed_reason = err; 3514 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3515 break; 3516 } 3517 3518 // generate random number first, if we need to show passkey 3519 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3520 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_conn->sm_handle); 3521 break; 3522 } 3523 3524 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3525 if (setup->sm_use_secure_connections){ 3526 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3527 if (setup->sm_stk_generation_method == JUST_WORKS){ 3528 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3529 sm_trigger_user_response(sm_conn); 3530 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3531 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3532 } 3533 } else { 3534 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3535 } 3536 break; 3537 } 3538 #endif 3539 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3540 sm_trigger_user_response(sm_conn); 3541 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3542 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3543 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3544 } 3545 break; 3546 3547 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3548 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3549 sm_pdu_received_in_wrong_state(sm_conn); 3550 break; 3551 } 3552 3553 // store s_confirm 3554 reverse_128(&packet[1], setup->sm_peer_confirm); 3555 3556 #ifdef ENABLE_TESTING_SUPPORT 3557 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3558 log_info("testing_support: reset confirm value"); 3559 memset(setup->sm_peer_confirm, 0, 16); 3560 } 3561 #endif 3562 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3563 break; 3564 3565 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3566 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3567 sm_pdu_received_in_wrong_state(sm_conn); 3568 break;; 3569 } 3570 3571 // received random value 3572 reverse_128(&packet[1], setup->sm_peer_random); 3573 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3574 break; 3575 #endif 3576 3577 #ifdef ENABLE_LE_PERIPHERAL 3578 // Responder 3579 case SM_RESPONDER_IDLE: 3580 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3581 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3582 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3583 sm_pdu_received_in_wrong_state(sm_conn); 3584 break;; 3585 } 3586 3587 // store pairing request 3588 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3589 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3590 break; 3591 #endif 3592 3593 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3594 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3595 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3596 sm_pdu_received_in_wrong_state(sm_conn); 3597 break; 3598 } 3599 3600 // store public key for DH Key calculation 3601 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3602 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3603 3604 // validate public key 3605 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3606 if (err){ 3607 log_error("sm: peer public key invalid %x", err); 3608 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3609 break; 3610 } 3611 3612 // start calculating dhkey 3613 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, (void*)(uintptr_t) sm_conn->sm_handle); 3614 3615 3616 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3617 if (IS_RESPONDER(sm_conn->sm_role)){ 3618 // responder 3619 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3620 } else { 3621 // initiator 3622 // stk generation method 3623 // passkey entry: notify app to show passkey or to request passkey 3624 switch (setup->sm_stk_generation_method){ 3625 case JUST_WORKS: 3626 case NUMERIC_COMPARISON: 3627 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3628 break; 3629 case PK_RESP_INPUT: 3630 sm_sc_start_calculating_local_confirm(sm_conn); 3631 break; 3632 case PK_INIT_INPUT: 3633 case PK_BOTH_INPUT: 3634 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3635 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3636 break; 3637 } 3638 sm_sc_start_calculating_local_confirm(sm_conn); 3639 break; 3640 case OOB: 3641 // generate Nx 3642 log_info("Generate Na"); 3643 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, (void*)(uintptr_t) sm_conn->sm_handle); 3644 break; 3645 } 3646 } 3647 break; 3648 3649 case SM_SC_W4_CONFIRMATION: 3650 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3651 sm_pdu_received_in_wrong_state(sm_conn); 3652 break; 3653 } 3654 // received confirm value 3655 reverse_128(&packet[1], setup->sm_peer_confirm); 3656 3657 #ifdef ENABLE_TESTING_SUPPORT 3658 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3659 log_info("testing_support: reset confirm value"); 3660 memset(setup->sm_peer_confirm, 0, 16); 3661 } 3662 #endif 3663 if (IS_RESPONDER(sm_conn->sm_role)){ 3664 // responder 3665 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3666 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3667 // still waiting for passkey 3668 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3669 break; 3670 } 3671 } 3672 sm_sc_start_calculating_local_confirm(sm_conn); 3673 } else { 3674 // initiator 3675 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3676 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3677 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, (void*)(uintptr_t) sm_conn->sm_handle); 3678 } else { 3679 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3680 } 3681 } 3682 break; 3683 3684 case SM_SC_W4_PAIRING_RANDOM: 3685 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3686 sm_pdu_received_in_wrong_state(sm_conn); 3687 break; 3688 } 3689 3690 // received random value 3691 reverse_128(&packet[1], setup->sm_peer_nonce); 3692 3693 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3694 // only check for JUST WORK/NC in initiator role OR passkey entry 3695 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3696 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3697 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3698 break; 3699 } 3700 3701 // OOB 3702 if (setup->sm_stk_generation_method == OOB){ 3703 3704 // setup local random, set to zero if remote did not receive our data 3705 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3706 if (IS_RESPONDER(sm_conn->sm_role)){ 3707 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3708 log_info("Reset rb as A does not have OOB data"); 3709 memset(setup->sm_rb, 0, 16); 3710 } else { 3711 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3712 log_info("Use stored rb"); 3713 log_info_hexdump(setup->sm_rb, 16); 3714 } 3715 } else { 3716 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3717 log_info("Reset ra as B does not have OOB data"); 3718 memset(setup->sm_ra, 0, 16); 3719 } else { 3720 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3721 log_info("Use stored ra"); 3722 log_info_hexdump(setup->sm_ra, 16); 3723 } 3724 } 3725 3726 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3727 if (setup->sm_have_oob_data){ 3728 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3729 break; 3730 } 3731 } 3732 3733 // TODO: we only get here for Responder role with JW/NC 3734 sm_sc_state_after_receiving_random(sm_conn); 3735 break; 3736 3737 case SM_SC_W2_CALCULATE_G2: 3738 case SM_SC_W4_CALCULATE_G2: 3739 case SM_SC_W4_CALCULATE_DHKEY: 3740 case SM_SC_W2_CALCULATE_F5_SALT: 3741 case SM_SC_W4_CALCULATE_F5_SALT: 3742 case SM_SC_W2_CALCULATE_F5_MACKEY: 3743 case SM_SC_W4_CALCULATE_F5_MACKEY: 3744 case SM_SC_W2_CALCULATE_F5_LTK: 3745 case SM_SC_W4_CALCULATE_F5_LTK: 3746 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3747 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3748 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3749 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3750 sm_pdu_received_in_wrong_state(sm_conn); 3751 break; 3752 } 3753 // store DHKey Check 3754 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3755 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3756 3757 // have we been only waiting for dhkey check command? 3758 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3759 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3760 } 3761 break; 3762 #endif 3763 3764 #ifdef ENABLE_LE_PERIPHERAL 3765 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3766 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3767 sm_pdu_received_in_wrong_state(sm_conn); 3768 break; 3769 } 3770 3771 // received confirm value 3772 reverse_128(&packet[1], setup->sm_peer_confirm); 3773 3774 #ifdef ENABLE_TESTING_SUPPORT 3775 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3776 log_info("testing_support: reset confirm value"); 3777 memset(setup->sm_peer_confirm, 0, 16); 3778 } 3779 #endif 3780 // notify client to hide shown passkey 3781 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3782 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3783 } 3784 3785 // handle user cancel pairing? 3786 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3787 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3788 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3789 break; 3790 } 3791 3792 // wait for user action? 3793 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3794 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3795 break; 3796 } 3797 3798 // calculate and send local_confirm 3799 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3800 break; 3801 3802 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3803 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3804 sm_pdu_received_in_wrong_state(sm_conn); 3805 break;; 3806 } 3807 3808 // received random value 3809 reverse_128(&packet[1], setup->sm_peer_random); 3810 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3811 break; 3812 #endif 3813 3814 case SM_PH3_RECEIVE_KEYS: 3815 switch(sm_pdu_code){ 3816 case SM_CODE_ENCRYPTION_INFORMATION: 3817 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3818 reverse_128(&packet[1], setup->sm_peer_ltk); 3819 break; 3820 3821 case SM_CODE_MASTER_IDENTIFICATION: 3822 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3823 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3824 reverse_64(&packet[3], setup->sm_peer_rand); 3825 break; 3826 3827 case SM_CODE_IDENTITY_INFORMATION: 3828 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3829 reverse_128(&packet[1], setup->sm_peer_irk); 3830 break; 3831 3832 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3833 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3834 setup->sm_peer_addr_type = packet[1]; 3835 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3836 break; 3837 3838 case SM_CODE_SIGNING_INFORMATION: 3839 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3840 reverse_128(&packet[1], setup->sm_peer_csrk); 3841 break; 3842 default: 3843 // Unexpected PDU 3844 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3845 break; 3846 } 3847 // done with key distribution? 3848 if (sm_key_distribution_all_received(sm_conn)){ 3849 3850 sm_key_distribution_handle_all_received(sm_conn); 3851 3852 if (IS_RESPONDER(sm_conn->sm_role)){ 3853 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3854 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3855 } else { 3856 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3857 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3858 sm_done_for_handle(sm_conn->sm_handle); 3859 } 3860 } else { 3861 if (setup->sm_use_secure_connections){ 3862 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3863 } else { 3864 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3865 } 3866 } 3867 } 3868 break; 3869 default: 3870 // Unexpected PDU 3871 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3872 break; 3873 } 3874 3875 // try to send preparared packet 3876 sm_run(); 3877 } 3878 3879 // Security Manager Client API 3880 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3881 sm_get_oob_data = get_oob_data_callback; 3882 } 3883 3884 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)){ 3885 sm_get_sc_oob_data = get_sc_oob_data_callback; 3886 } 3887 3888 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3889 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3890 } 3891 3892 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3893 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3894 } 3895 3896 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3897 sm_min_encryption_key_size = min_size; 3898 sm_max_encryption_key_size = max_size; 3899 } 3900 3901 void sm_set_authentication_requirements(uint8_t auth_req){ 3902 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3903 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3904 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3905 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3906 } 3907 #endif 3908 sm_auth_req = auth_req; 3909 } 3910 3911 void sm_set_io_capabilities(io_capability_t io_capability){ 3912 sm_io_capabilities = io_capability; 3913 } 3914 3915 #ifdef ENABLE_LE_PERIPHERAL 3916 void sm_set_request_security(int enable){ 3917 sm_slave_request_security = enable; 3918 } 3919 #endif 3920 3921 void sm_set_er(sm_key_t er){ 3922 memcpy(sm_persistent_er, er, 16); 3923 } 3924 3925 void sm_set_ir(sm_key_t ir){ 3926 memcpy(sm_persistent_ir, ir, 16); 3927 } 3928 3929 // Testing support only 3930 void sm_test_set_irk(sm_key_t irk){ 3931 memcpy(sm_persistent_irk, irk, 16); 3932 dkg_state = DKG_CALC_DHK; 3933 } 3934 3935 void sm_test_use_fixed_local_csrk(void){ 3936 test_use_fixed_local_csrk = 1; 3937 } 3938 3939 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3940 static void sm_ec_generated(void * arg){ 3941 UNUSED(arg); 3942 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3943 // trigger pairing if pending for ec key 3944 sm_run(); 3945 } 3946 static void sm_ec_generate_new_key(void){ 3947 log_info("sm: generate new ec key"); 3948 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3949 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3950 } 3951 #endif 3952 3953 #ifdef ENABLE_TESTING_SUPPORT 3954 void sm_test_set_pairing_failure(int reason){ 3955 test_pairing_failure = reason; 3956 } 3957 #endif 3958 3959 void sm_init(void){ 3960 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3961 sm_er_ir_set_default(); 3962 3963 // defaults 3964 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3965 | SM_STK_GENERATION_METHOD_OOB 3966 | SM_STK_GENERATION_METHOD_PASSKEY 3967 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3968 3969 sm_max_encryption_key_size = 16; 3970 sm_min_encryption_key_size = 7; 3971 3972 sm_fixed_passkey_in_display_role = 0xffffffff; 3973 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3974 3975 #ifdef USE_CMAC_ENGINE 3976 sm_cmac_active = 0; 3977 #endif 3978 dkg_state = DKG_W4_WORKING; 3979 rau_state = RAU_IDLE; 3980 sm_aes128_state = SM_AES128_IDLE; 3981 sm_address_resolution_test = -1; // no private address to resolve yet 3982 sm_address_resolution_ah_calculation_active = 0; 3983 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3984 sm_address_resolution_general_queue = NULL; 3985 3986 gap_random_adress_update_period = 15 * 60 * 1000L; 3987 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3988 3989 test_use_fixed_local_csrk = 0; 3990 3991 // register for HCI Events from HCI 3992 hci_event_callback_registration.callback = &sm_event_packet_handler; 3993 hci_add_event_handler(&hci_event_callback_registration); 3994 3995 // 3996 btstack_crypto_init(); 3997 3998 // init le_device_db 3999 le_device_db_init(); 4000 4001 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4002 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4003 4004 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4005 sm_ec_generate_new_key(); 4006 #endif 4007 } 4008 4009 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4010 sm_fixed_passkey_in_display_role = passkey; 4011 } 4012 4013 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4014 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4015 } 4016 4017 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4018 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4019 if (!hci_con) return NULL; 4020 return &hci_con->sm_connection; 4021 } 4022 4023 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4024 switch (sm_conn->sm_engine_state){ 4025 case SM_GENERAL_IDLE: 4026 case SM_RESPONDER_IDLE: 4027 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4028 sm_run(); 4029 break; 4030 default: 4031 break; 4032 } 4033 } 4034 4035 /** 4036 * @brief Trigger Security Request 4037 */ 4038 void sm_send_security_request(hci_con_handle_t con_handle){ 4039 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4040 if (!sm_conn) return; 4041 sm_send_security_request_for_connection(sm_conn); 4042 } 4043 4044 // request pairing 4045 void sm_request_pairing(hci_con_handle_t con_handle){ 4046 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4047 if (!sm_conn) return; // wrong connection 4048 4049 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4050 if (IS_RESPONDER(sm_conn->sm_role)){ 4051 sm_send_security_request_for_connection(sm_conn); 4052 } else { 4053 // used as a trigger to start central/master/initiator security procedures 4054 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4055 uint8_t ltk[16]; 4056 switch (sm_conn->sm_irk_lookup_state){ 4057 case IRK_LOOKUP_SUCCEEDED: 4058 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4059 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4060 log_info("have ltk %u", !sm_is_null_key(ltk)); 4061 // trigger 'pairing complete' event on encryption change 4062 sm_conn->sm_pairing_requested = 1; 4063 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4064 break; 4065 #endif 4066 /* explicit fall-through */ 4067 4068 case IRK_LOOKUP_FAILED: 4069 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4070 break; 4071 default: 4072 log_info("irk lookup pending"); 4073 sm_conn->sm_pairing_requested = 1; 4074 break; 4075 } 4076 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4077 sm_conn->sm_pairing_requested = 1; 4078 } 4079 } 4080 sm_run(); 4081 } 4082 4083 // called by client app on authorization request 4084 void sm_authorization_decline(hci_con_handle_t con_handle){ 4085 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4086 if (!sm_conn) return; // wrong connection 4087 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4088 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4089 } 4090 4091 void sm_authorization_grant(hci_con_handle_t con_handle){ 4092 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4093 if (!sm_conn) return; // wrong connection 4094 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4095 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4096 } 4097 4098 // GAP Bonding API 4099 4100 void sm_bonding_decline(hci_con_handle_t con_handle){ 4101 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4102 if (!sm_conn) return; // wrong connection 4103 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4104 log_info("decline, state %u", sm_conn->sm_engine_state); 4105 switch(sm_conn->sm_engine_state){ 4106 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4107 case SM_SC_W4_USER_RESPONSE: 4108 case SM_SC_W4_CONFIRMATION: 4109 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4110 #endif 4111 case SM_PH1_W4_USER_RESPONSE: 4112 switch (setup->sm_stk_generation_method){ 4113 case PK_RESP_INPUT: 4114 case PK_INIT_INPUT: 4115 case PK_BOTH_INPUT: 4116 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4117 break; 4118 case NUMERIC_COMPARISON: 4119 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4120 break; 4121 case JUST_WORKS: 4122 case OOB: 4123 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4124 break; 4125 } 4126 break; 4127 default: 4128 break; 4129 } 4130 sm_run(); 4131 } 4132 4133 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4134 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4135 if (!sm_conn) return; // wrong connection 4136 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4137 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4138 if (setup->sm_use_secure_connections){ 4139 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4140 } else { 4141 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4142 } 4143 } 4144 4145 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4146 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4147 sm_sc_prepare_dhkey_check(sm_conn); 4148 } 4149 #endif 4150 4151 sm_run(); 4152 } 4153 4154 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4155 // for now, it's the same 4156 sm_just_works_confirm(con_handle); 4157 } 4158 4159 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4160 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4161 if (!sm_conn) return; // wrong connection 4162 sm_reset_tk(); 4163 big_endian_store_32(setup->sm_tk, 12, passkey); 4164 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4165 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4166 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4167 } 4168 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4169 memcpy(setup->sm_ra, setup->sm_tk, 16); 4170 memcpy(setup->sm_rb, setup->sm_tk, 16); 4171 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4172 sm_sc_start_calculating_local_confirm(sm_conn); 4173 } 4174 #endif 4175 sm_run(); 4176 } 4177 4178 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4179 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4180 if (!sm_conn) return; // wrong connection 4181 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4182 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4183 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4184 switch (action){ 4185 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4186 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4187 flags |= (1 << action); 4188 break; 4189 case SM_KEYPRESS_PASSKEY_CLEARED: 4190 // clear counter, keypress & erased flags + set passkey cleared 4191 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4192 break; 4193 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4194 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4195 // erase actions queued 4196 num_actions--; 4197 if (num_actions == 0){ 4198 // clear counter, keypress & erased flags 4199 flags &= 0x19; 4200 } 4201 break; 4202 } 4203 num_actions++; 4204 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4205 break; 4206 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4207 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4208 // enter actions queued 4209 num_actions--; 4210 if (num_actions == 0){ 4211 // clear counter, keypress & erased flags 4212 flags &= 0x19; 4213 } 4214 break; 4215 } 4216 num_actions++; 4217 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4218 break; 4219 default: 4220 break; 4221 } 4222 setup->sm_keypress_notification = (num_actions << 5) | flags; 4223 sm_run(); 4224 } 4225 4226 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4227 static void sm_handle_random_result_oob(void * arg){ 4228 UNUSED(arg); 4229 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4230 sm_run(); 4231 } 4232 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4233 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4234 sm_sc_oob_callback = callback; 4235 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4236 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4237 return 0; 4238 } 4239 #endif 4240 4241 /** 4242 * @brief Get Identity Resolving state 4243 * @param con_handle 4244 * @return irk_lookup_state_t 4245 */ 4246 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4247 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4248 if (!sm_conn) return IRK_LOOKUP_IDLE; 4249 return sm_conn->sm_irk_lookup_state; 4250 } 4251 4252 /** 4253 * @brief Identify device in LE Device DB 4254 * @param handle 4255 * @returns index from le_device_db or -1 if not found/identified 4256 */ 4257 int sm_le_device_index(hci_con_handle_t con_handle ){ 4258 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4259 if (!sm_conn) return -1; 4260 return sm_conn->sm_le_db_index; 4261 } 4262 4263 static int gap_random_address_type_requires_updates(void){ 4264 switch (gap_random_adress_type){ 4265 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4266 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4267 return 0; 4268 default: 4269 return 1; 4270 } 4271 } 4272 4273 static uint8_t own_address_type(void){ 4274 switch (gap_random_adress_type){ 4275 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4276 return BD_ADDR_TYPE_LE_PUBLIC; 4277 default: 4278 return BD_ADDR_TYPE_LE_RANDOM; 4279 } 4280 } 4281 4282 // GAP LE API 4283 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4284 gap_random_address_update_stop(); 4285 gap_random_adress_type = random_address_type; 4286 hci_le_set_own_address_type(own_address_type()); 4287 if (!gap_random_address_type_requires_updates()) return; 4288 gap_random_address_update_start(); 4289 gap_random_address_trigger(); 4290 } 4291 4292 gap_random_address_type_t gap_random_address_get_mode(void){ 4293 return gap_random_adress_type; 4294 } 4295 4296 void gap_random_address_set_update_period(int period_ms){ 4297 gap_random_adress_update_period = period_ms; 4298 if (!gap_random_address_type_requires_updates()) return; 4299 gap_random_address_update_stop(); 4300 gap_random_address_update_start(); 4301 } 4302 4303 void gap_random_address_set(bd_addr_t addr){ 4304 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4305 memcpy(sm_random_address, addr, 6); 4306 rau_state = RAU_SET_ADDRESS; 4307 sm_run(); 4308 } 4309 4310 #ifdef ENABLE_LE_PERIPHERAL 4311 /* 4312 * @brief Set Advertisement Paramters 4313 * @param adv_int_min 4314 * @param adv_int_max 4315 * @param adv_type 4316 * @param direct_address_type 4317 * @param direct_address 4318 * @param channel_map 4319 * @param filter_policy 4320 * 4321 * @note own_address_type is used from gap_random_address_set_mode 4322 */ 4323 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4324 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4325 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4326 direct_address_typ, direct_address, channel_map, filter_policy); 4327 } 4328 #endif 4329 4330 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4331 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4332 // wrong connection 4333 if (!sm_conn) return 0; 4334 // already encrypted 4335 if (sm_conn->sm_connection_encrypted) return 0; 4336 // only central can re-encrypt 4337 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4338 // irk status? 4339 switch(sm_conn->sm_irk_lookup_state){ 4340 case IRK_LOOKUP_FAILED: 4341 // done, cannot setup encryption 4342 return 0; 4343 case IRK_LOOKUP_SUCCEEDED: 4344 break; 4345 default: 4346 // IR Lookup pending 4347 return 1; 4348 } 4349 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4350 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4351 } 4352