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_next_w2_cmac_for_confirmation(void * arg); 426 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 427 static int sm_passkey_entry(stk_generation_method_t method); 428 #endif 429 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 430 431 static void log_info_hex16(const char * name, uint16_t value){ 432 log_info("%-6s 0x%04x", name, value); 433 } 434 435 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 436 // return packet[0]; 437 // } 438 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 439 return packet[1]; 440 } 441 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 442 return packet[2]; 443 } 444 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 445 return packet[3]; 446 } 447 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 448 return packet[4]; 449 } 450 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 451 return packet[5]; 452 } 453 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 454 return packet[6]; 455 } 456 457 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 458 packet[0] = code; 459 } 460 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 461 packet[1] = io_capability; 462 } 463 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 464 packet[2] = oob_data_flag; 465 } 466 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 467 packet[3] = auth_req; 468 } 469 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 470 packet[4] = max_encryption_key_size; 471 } 472 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 473 packet[5] = initiator_key_distribution; 474 } 475 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 476 packet[6] = responder_key_distribution; 477 } 478 479 // @returns 1 if all bytes are 0 480 static int sm_is_null(uint8_t * data, int size){ 481 int i; 482 for (i=0; i < size ; i++){ 483 if (data[i]) return 0; 484 } 485 return 1; 486 } 487 488 static int sm_is_null_random(uint8_t random[8]){ 489 return sm_is_null(random, 8); 490 } 491 492 static int sm_is_null_key(uint8_t * key){ 493 return sm_is_null(key, 16); 494 } 495 496 // Key utils 497 static void sm_reset_tk(void){ 498 int i; 499 for (i=0;i<16;i++){ 500 setup->sm_tk[i] = 0; 501 } 502 } 503 504 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 505 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 506 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 507 int i; 508 for (i = max_encryption_size ; i < 16 ; i++){ 509 key[15-i] = 0; 510 } 511 } 512 513 // ER / IR checks 514 static void sm_er_ir_set_default(void){ 515 int i; 516 for (i=0;i<16;i++){ 517 sm_persistent_er[i] = 0x30 + i; 518 sm_persistent_ir[i] = 0x90 + i; 519 } 520 } 521 522 static int sm_er_is_default(void){ 523 int i; 524 for (i=0;i<16;i++){ 525 if (sm_persistent_er[i] != (0x30+i)) return 0; 526 } 527 return 1; 528 } 529 530 static int sm_ir_is_default(void){ 531 int i; 532 for (i=0;i<16;i++){ 533 if (sm_persistent_ir[i] != (0x90+i)) return 0; 534 } 535 return 1; 536 } 537 538 // SMP Timeout implementation 539 540 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 541 // the Security Manager Timer shall be reset and started. 542 // 543 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 544 // 545 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 546 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 547 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 548 // established. 549 550 static void sm_timeout_handler(btstack_timer_source_t * timer){ 551 log_info("SM timeout"); 552 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 553 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 554 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 555 sm_done_for_handle(sm_conn->sm_handle); 556 557 // trigger handling of next ready connection 558 sm_run(); 559 } 560 static void sm_timeout_start(sm_connection_t * sm_conn){ 561 btstack_run_loop_remove_timer(&setup->sm_timeout); 562 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 563 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 564 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 565 btstack_run_loop_add_timer(&setup->sm_timeout); 566 } 567 static void sm_timeout_stop(void){ 568 btstack_run_loop_remove_timer(&setup->sm_timeout); 569 } 570 static void sm_timeout_reset(sm_connection_t * sm_conn){ 571 sm_timeout_stop(); 572 sm_timeout_start(sm_conn); 573 } 574 575 // end of sm timeout 576 577 // GAP Random Address updates 578 static gap_random_address_type_t gap_random_adress_type; 579 static btstack_timer_source_t gap_random_address_update_timer; 580 static uint32_t gap_random_adress_update_period; 581 582 static void gap_random_address_trigger(void){ 583 log_info("gap_random_address_trigger, state %u", rau_state); 584 if (rau_state != RAU_IDLE) return; 585 rau_state = RAU_GET_RANDOM; 586 sm_run(); 587 } 588 589 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 590 UNUSED(timer); 591 592 log_info("GAP Random Address Update due"); 593 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 594 btstack_run_loop_add_timer(&gap_random_address_update_timer); 595 gap_random_address_trigger(); 596 } 597 598 static void gap_random_address_update_start(void){ 599 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 600 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 601 btstack_run_loop_add_timer(&gap_random_address_update_timer); 602 } 603 604 static void gap_random_address_update_stop(void){ 605 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 606 } 607 608 // ah(k,r) helper 609 // r = padding || r 610 // r - 24 bit value 611 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 612 // r'= padding || r 613 memset(r_prime, 0, 16); 614 memcpy(&r_prime[13], r, 3); 615 } 616 617 // d1 helper 618 // d' = padding || r || d 619 // d,r - 16 bit values 620 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 621 // d'= padding || r || d 622 memset(d1_prime, 0, 16); 623 big_endian_store_16(d1_prime, 12, r); 624 big_endian_store_16(d1_prime, 14, d); 625 } 626 627 // dm helper 628 // r’ = padding || r 629 // r - 64 bit value 630 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 631 memset(r_prime, 0, 16); 632 memcpy(&r_prime[8], r, 8); 633 } 634 635 // calculate arguments for first AES128 operation in C1 function 636 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){ 637 638 // p1 = pres || preq || rat’ || iat’ 639 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 640 // cant octet of pres becomes the most significant octet of p1. 641 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 642 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 643 // p1 is 0x05000800000302070710000001010001." 644 645 sm_key_t p1; 646 reverse_56(pres, &p1[0]); 647 reverse_56(preq, &p1[7]); 648 p1[14] = rat; 649 p1[15] = iat; 650 log_info_key("p1", p1); 651 log_info_key("r", r); 652 653 // t1 = r xor p1 654 int i; 655 for (i=0;i<16;i++){ 656 t1[i] = r[i] ^ p1[i]; 657 } 658 log_info_key("t1", t1); 659 } 660 661 // calculate arguments for second AES128 operation in C1 function 662 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 663 // p2 = padding || ia || ra 664 // "The least significant octet of ra becomes the least significant octet of p2 and 665 // the most significant octet of padding becomes the most significant octet of p2. 666 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 667 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 668 669 sm_key_t p2; 670 memset(p2, 0, 16); 671 memcpy(&p2[4], ia, 6); 672 memcpy(&p2[10], ra, 6); 673 log_info_key("p2", p2); 674 675 // c1 = e(k, t2_xor_p2) 676 int i; 677 for (i=0;i<16;i++){ 678 t3[i] = t2[i] ^ p2[i]; 679 } 680 log_info_key("t3", t3); 681 } 682 683 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 684 log_info_key("r1", r1); 685 log_info_key("r2", r2); 686 memcpy(&r_prime[8], &r2[8], 8); 687 memcpy(&r_prime[0], &r1[8], 8); 688 } 689 690 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 691 UNUSED(channel); 692 693 // log event 694 hci_dump_packet(packet_type, 1, packet, size); 695 // dispatch to all event handlers 696 btstack_linked_list_iterator_t it; 697 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 698 while (btstack_linked_list_iterator_has_next(&it)){ 699 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 700 entry->callback(packet_type, 0, packet, size); 701 } 702 } 703 704 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){ 705 event[0] = type; 706 event[1] = event_size - 2; 707 little_endian_store_16(event, 2, con_handle); 708 event[4] = addr_type; 709 reverse_bd_addr(address, &event[5]); 710 } 711 712 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 713 uint8_t event[11]; 714 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 715 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 716 } 717 718 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){ 719 uint8_t event[15]; 720 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 721 little_endian_store_32(event, 11, passkey); 722 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 723 } 724 725 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){ 726 // fetch addr and addr type from db, only called for valid entries 727 bd_addr_t identity_address; 728 int identity_address_type; 729 le_device_db_info(index, &identity_address_type, identity_address, NULL); 730 731 uint8_t event[20]; 732 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 733 event[11] = identity_address_type; 734 reverse_bd_addr(identity_address, &event[12]); 735 little_endian_store_16(event, 18, index); 736 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 737 } 738 739 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){ 740 uint8_t event[12]; 741 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 742 event[11] = status; 743 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 744 } 745 746 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 747 uint8_t event[13]; 748 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 749 event[11] = status; 750 event[12] = reason; 751 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 752 } 753 754 // decide on stk generation based on 755 // - pairing request 756 // - io capabilities 757 // - OOB data availability 758 static void sm_setup_tk(void){ 759 760 // default: just works 761 setup->sm_stk_generation_method = JUST_WORKS; 762 763 #ifdef ENABLE_LE_SECURE_CONNECTIONS 764 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 765 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 766 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 767 #else 768 setup->sm_use_secure_connections = 0; 769 #endif 770 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 771 772 773 // decide if OOB will be used based on SC vs. Legacy and oob flags 774 int use_oob = 0; 775 if (setup->sm_use_secure_connections){ 776 // In LE Secure Connections pairing, the out of band method is used if at least 777 // one device has the peer device's out of band authentication data available. 778 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 779 } else { 780 // In LE legacy pairing, the out of band method is used if both the devices have 781 // the other device's out of band authentication data available. 782 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 783 } 784 if (use_oob){ 785 log_info("SM: have OOB data"); 786 log_info_key("OOB", setup->sm_tk); 787 setup->sm_stk_generation_method = OOB; 788 return; 789 } 790 791 // If both devices have not set the MITM option in the Authentication Requirements 792 // Flags, then the IO capabilities shall be ignored and the Just Works association 793 // model shall be used. 794 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 795 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 796 log_info("SM: MITM not required by both -> JUST WORKS"); 797 return; 798 } 799 800 // Reset TK as it has been setup in sm_init_setup 801 sm_reset_tk(); 802 803 // Also use just works if unknown io capabilites 804 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)){ 805 return; 806 } 807 808 // Otherwise the IO capabilities of the devices shall be used to determine the 809 // pairing method as defined in Table 2.4. 810 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 811 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 812 813 #ifdef ENABLE_LE_SECURE_CONNECTIONS 814 // table not define by default 815 if (setup->sm_use_secure_connections){ 816 generation_method = stk_generation_method_with_secure_connection; 817 } 818 #endif 819 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)]; 820 821 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 822 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); 823 } 824 825 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 826 int flags = 0; 827 if (key_set & SM_KEYDIST_ENC_KEY){ 828 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 829 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 830 } 831 if (key_set & SM_KEYDIST_ID_KEY){ 832 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 833 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 834 } 835 if (key_set & SM_KEYDIST_SIGN){ 836 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 837 } 838 return flags; 839 } 840 841 static void sm_setup_key_distribution(uint8_t key_set){ 842 setup->sm_key_distribution_received_set = 0; 843 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 844 setup->sm_key_distribution_sent_set = 0; 845 #ifdef ENABLE_LE_SIGNED_WRITE 846 setup->sm_le_device_index = -1; 847 #endif 848 } 849 850 // CSRK Key Lookup 851 852 853 static int sm_address_resolution_idle(void){ 854 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 855 } 856 857 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){ 858 memcpy(sm_address_resolution_address, addr, 6); 859 sm_address_resolution_addr_type = addr_type; 860 sm_address_resolution_test = 0; 861 sm_address_resolution_mode = mode; 862 sm_address_resolution_context = context; 863 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 864 } 865 866 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 867 // check if already in list 868 btstack_linked_list_iterator_t it; 869 sm_lookup_entry_t * entry; 870 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 871 while(btstack_linked_list_iterator_has_next(&it)){ 872 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 873 if (entry->address_type != address_type) continue; 874 if (memcmp(entry->address, address, 6)) continue; 875 // already in list 876 return BTSTACK_BUSY; 877 } 878 entry = btstack_memory_sm_lookup_entry_get(); 879 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 880 entry->address_type = (bd_addr_type_t) address_type; 881 memcpy(entry->address, address, 6); 882 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 883 sm_run(); 884 return 0; 885 } 886 887 // CMAC calculation using AES Engineq 888 #ifdef USE_CMAC_ENGINE 889 890 static void sm_cmac_done_trampoline(void * arg){ 891 UNUSED(arg); 892 sm_cmac_active = 0; 893 (*sm_cmac_done_callback)(sm_cmac_hash); 894 sm_run(); 895 } 896 897 int sm_cmac_ready(void){ 898 return sm_cmac_active == 0; 899 } 900 #endif 901 902 #ifdef ENABLE_LE_SECURE_CONNECTIONS 903 // generic cmac calculation 904 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)){ 905 sm_cmac_active = 1; 906 sm_cmac_done_callback = done_callback; 907 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 908 } 909 #endif 910 911 // cmac for ATT Message signing 912 #ifdef ENABLE_LE_SIGNED_WRITE 913 914 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)){ 915 sm_cmac_active = 1; 916 sm_cmac_done_callback = done_callback; 917 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 918 } 919 920 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 921 if (offset >= sm_cmac_signed_write_message_len) { 922 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 923 return 0; 924 } 925 926 offset = sm_cmac_signed_write_message_len - 1 - offset; 927 928 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 929 if (offset < 3){ 930 return sm_cmac_signed_write_header[offset]; 931 } 932 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 933 if (offset < actual_message_len_incl_header){ 934 return sm_cmac_signed_write_message[offset - 3]; 935 } 936 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 937 } 938 939 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)){ 940 // ATT Message Signing 941 sm_cmac_signed_write_header[0] = opcode; 942 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 943 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 944 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 945 sm_cmac_signed_write_message = message; 946 sm_cmac_signed_write_message_len = total_message_len; 947 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 948 } 949 #endif 950 951 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 952 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 953 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 954 switch (setup->sm_stk_generation_method){ 955 case PK_RESP_INPUT: 956 if (IS_RESPONDER(sm_conn->sm_role)){ 957 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 958 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 959 } else { 960 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)); 961 } 962 break; 963 case PK_INIT_INPUT: 964 if (IS_RESPONDER(sm_conn->sm_role)){ 965 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)); 966 } else { 967 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 968 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 969 } 970 break; 971 case PK_BOTH_INPUT: 972 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 973 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 974 break; 975 case NUMERIC_COMPARISON: 976 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 977 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)); 978 break; 979 case JUST_WORKS: 980 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 981 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 982 break; 983 case OOB: 984 // client already provided OOB data, let's skip notification. 985 break; 986 } 987 } 988 989 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 990 int recv_flags; 991 if (IS_RESPONDER(sm_conn->sm_role)){ 992 // slave / responder 993 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 994 } else { 995 // master / initiator 996 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 997 } 998 999 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1000 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1001 if (setup->sm_use_secure_connections){ 1002 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1003 } 1004 #endif 1005 1006 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1007 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1008 } 1009 1010 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1011 if (sm_active_connection_handle == con_handle){ 1012 sm_timeout_stop(); 1013 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1014 log_info("sm: connection 0x%x released setup context", con_handle); 1015 1016 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1017 // generate new ec key after each pairing (that used it) 1018 if (setup->sm_use_secure_connections){ 1019 sm_ec_generate_new_key(); 1020 } 1021 #endif 1022 } 1023 } 1024 1025 static int sm_key_distribution_flags_for_auth_req(void){ 1026 1027 int flags = SM_KEYDIST_ID_KEY; 1028 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1029 // encryption and signing information only if bonding requested 1030 flags |= SM_KEYDIST_ENC_KEY; 1031 #ifdef ENABLE_LE_SIGNED_WRITE 1032 flags |= SM_KEYDIST_SIGN; 1033 #endif 1034 } 1035 return flags; 1036 } 1037 1038 static void sm_reset_setup(void){ 1039 // fill in sm setup 1040 setup->sm_state_vars = 0; 1041 setup->sm_keypress_notification = 0; 1042 sm_reset_tk(); 1043 } 1044 1045 static void sm_init_setup(sm_connection_t * sm_conn){ 1046 1047 // fill in sm setup 1048 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1049 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1050 1051 // query client for Legacy Pairing OOB data 1052 setup->sm_have_oob_data = 0; 1053 if (sm_get_oob_data) { 1054 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1055 } 1056 1057 // if available and SC supported, also ask for SC OOB Data 1058 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1059 memset(setup->sm_ra, 0, 16); 1060 memset(setup->sm_rb, 0, 16); 1061 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1062 if (sm_get_sc_oob_data){ 1063 if (IS_RESPONDER(sm_conn->sm_role)){ 1064 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1065 sm_conn->sm_peer_addr_type, 1066 sm_conn->sm_peer_address, 1067 setup->sm_peer_confirm, 1068 setup->sm_ra); 1069 } else { 1070 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1071 sm_conn->sm_peer_addr_type, 1072 sm_conn->sm_peer_address, 1073 setup->sm_peer_confirm, 1074 setup->sm_rb); 1075 } 1076 } else { 1077 setup->sm_have_oob_data = 0; 1078 } 1079 } 1080 #endif 1081 1082 sm_pairing_packet_t * local_packet; 1083 if (IS_RESPONDER(sm_conn->sm_role)){ 1084 // slave 1085 local_packet = &setup->sm_s_pres; 1086 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1087 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1088 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1089 } else { 1090 // master 1091 local_packet = &setup->sm_m_preq; 1092 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1093 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1094 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1095 1096 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1097 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1098 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1099 } 1100 1101 uint8_t auth_req = sm_auth_req; 1102 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1103 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1104 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1105 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1106 } 1107 1108 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1109 1110 sm_pairing_packet_t * remote_packet; 1111 int remote_key_request; 1112 if (IS_RESPONDER(sm_conn->sm_role)){ 1113 // slave / responder 1114 remote_packet = &setup->sm_m_preq; 1115 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1116 } else { 1117 // master / initiator 1118 remote_packet = &setup->sm_s_pres; 1119 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1120 } 1121 1122 // check key size 1123 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1124 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1125 1126 // decide on STK generation method / SC 1127 sm_setup_tk(); 1128 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1129 1130 // check if STK generation method is acceptable by client 1131 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1132 1133 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1134 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1135 if (setup->sm_use_secure_connections){ 1136 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1137 } 1138 #endif 1139 1140 // identical to responder 1141 sm_setup_key_distribution(remote_key_request); 1142 1143 // JUST WORKS doens't provide authentication 1144 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1145 1146 return 0; 1147 } 1148 1149 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1150 1151 // cache and reset context 1152 int matched_device_id = sm_address_resolution_test; 1153 address_resolution_mode_t mode = sm_address_resolution_mode; 1154 void * context = sm_address_resolution_context; 1155 1156 // reset context 1157 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1158 sm_address_resolution_context = NULL; 1159 sm_address_resolution_test = -1; 1160 hci_con_handle_t con_handle = 0; 1161 1162 sm_connection_t * sm_connection; 1163 #ifdef ENABLE_LE_CENTRAL 1164 sm_key_t ltk; 1165 int have_ltk; 1166 int pairing_need; 1167 #endif 1168 switch (mode){ 1169 case ADDRESS_RESOLUTION_GENERAL: 1170 break; 1171 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1172 sm_connection = (sm_connection_t *) context; 1173 con_handle = sm_connection->sm_handle; 1174 switch (event){ 1175 case ADDRESS_RESOLUTION_SUCEEDED: 1176 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1177 sm_connection->sm_le_db_index = matched_device_id; 1178 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1179 if (sm_connection->sm_role) { 1180 // LTK request received before, IRK required -> start LTK calculation 1181 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1182 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1183 } 1184 break; 1185 } 1186 #ifdef ENABLE_LE_CENTRAL 1187 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1188 have_ltk = !sm_is_null_key(ltk); 1189 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1190 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1191 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1192 // reset requests 1193 sm_connection->sm_security_request_received = 0; 1194 sm_connection->sm_pairing_requested = 0; 1195 1196 // have ltk -> start encryption 1197 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1198 // "When a bond has been created between two devices, any reconnection should result in the local device 1199 // enabling or requesting encryption with the remote device before initiating any service request." 1200 if (have_ltk){ 1201 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1202 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1203 break; 1204 #else 1205 log_info("central: defer enabling encryption for bonded device"); 1206 #endif 1207 } 1208 // pairint_request -> send pairing request 1209 if (pairing_need){ 1210 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1211 break; 1212 } 1213 #endif 1214 break; 1215 case ADDRESS_RESOLUTION_FAILED: 1216 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1217 if (sm_connection->sm_role) { 1218 // LTK request received before, IRK required -> negative LTK reply 1219 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1220 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1221 } 1222 break; 1223 } 1224 #ifdef ENABLE_LE_CENTRAL 1225 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1226 sm_connection->sm_security_request_received = 0; 1227 sm_connection->sm_pairing_requested = 0; 1228 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1229 #endif 1230 break; 1231 } 1232 break; 1233 default: 1234 break; 1235 } 1236 1237 switch (event){ 1238 case ADDRESS_RESOLUTION_SUCEEDED: 1239 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1240 break; 1241 case ADDRESS_RESOLUTION_FAILED: 1242 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1243 break; 1244 } 1245 } 1246 1247 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1248 1249 int le_db_index = -1; 1250 1251 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1252 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1253 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1254 & SM_AUTHREQ_BONDING ) != 0; 1255 1256 if (bonding_enabed){ 1257 1258 // lookup device based on IRK 1259 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1260 int i; 1261 for (i=0; i < le_device_db_max_count(); i++){ 1262 sm_key_t irk; 1263 bd_addr_t address; 1264 int address_type = BD_ADDR_TYPE_UNKNOWN; 1265 le_device_db_info(i, &address_type, address, irk); 1266 // skip unused entries 1267 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1268 // compare IRK 1269 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1270 1271 log_info("sm: device found for IRK, updating"); 1272 le_db_index = i; 1273 break; 1274 } 1275 } else { 1276 // assert IRK is set to zero 1277 memset(setup->sm_peer_irk, 0, 16); 1278 } 1279 1280 // if not found, lookup via public address if possible 1281 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1282 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1283 int i; 1284 for (i=0; i < le_device_db_max_count(); i++){ 1285 bd_addr_t address; 1286 int address_type = BD_ADDR_TYPE_UNKNOWN; 1287 le_device_db_info(i, &address_type, address, NULL); 1288 // skip unused entries 1289 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1290 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1291 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1292 log_info("sm: device found for public address, updating"); 1293 le_db_index = i; 1294 break; 1295 } 1296 } 1297 } 1298 1299 // if not found, add to db 1300 if (le_db_index < 0) { 1301 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1302 } 1303 1304 if (le_db_index >= 0){ 1305 1306 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1307 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1308 1309 #ifdef ENABLE_LE_SIGNED_WRITE 1310 // store local CSRK 1311 setup->sm_le_device_index = le_db_index; 1312 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1313 log_info("sm: store local CSRK"); 1314 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1315 le_device_db_local_counter_set(le_db_index, 0); 1316 } 1317 1318 // store remote CSRK 1319 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1320 log_info("sm: store remote CSRK"); 1321 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1322 le_device_db_remote_counter_set(le_db_index, 0); 1323 } 1324 #endif 1325 // store encryption information for secure connections: LTK generated by ECDH 1326 if (setup->sm_use_secure_connections){ 1327 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1328 uint8_t zero_rand[8]; 1329 memset(zero_rand, 0, 8); 1330 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1331 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1332 } 1333 1334 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1335 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1336 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1337 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1338 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1339 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1340 1341 } 1342 } 1343 } else { 1344 log_info("Ignoring received keys, bonding not enabled"); 1345 } 1346 1347 // keep le_db_index 1348 sm_conn->sm_le_db_index = le_db_index; 1349 } 1350 1351 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1352 setup->sm_pairing_failed_reason = reason; 1353 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1354 } 1355 1356 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1357 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1358 } 1359 1360 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1361 1362 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1363 static int sm_passkey_used(stk_generation_method_t method); 1364 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1365 1366 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1367 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1368 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_w2_cmac_for_confirmation, (void *)(uintptr_t) sm_conn->sm_handle); 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 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void *)(uintptr_t) sm_conn->sm_handle); 1381 } else { 1382 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1383 } 1384 } else { 1385 // Initiator role 1386 switch (setup->sm_stk_generation_method){ 1387 case JUST_WORKS: 1388 sm_sc_prepare_dhkey_check(sm_conn); 1389 break; 1390 1391 case NUMERIC_COMPARISON: 1392 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1393 break; 1394 case PK_INIT_INPUT: 1395 case PK_RESP_INPUT: 1396 case PK_BOTH_INPUT: 1397 if (setup->sm_passkey_bit < 20) { 1398 sm_sc_start_calculating_local_confirm(sm_conn); 1399 } else { 1400 sm_sc_prepare_dhkey_check(sm_conn); 1401 } 1402 break; 1403 case OOB: 1404 sm_sc_prepare_dhkey_check(sm_conn); 1405 break; 1406 } 1407 } 1408 } 1409 1410 static void sm_sc_cmac_done(uint8_t * hash){ 1411 log_info("sm_sc_cmac_done: "); 1412 log_info_hexdump(hash, 16); 1413 1414 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1415 sm_sc_oob_state = SM_SC_OOB_IDLE; 1416 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1417 return; 1418 } 1419 1420 sm_connection_t * sm_conn = sm_cmac_connection; 1421 sm_cmac_connection = NULL; 1422 #ifdef ENABLE_CLASSIC 1423 link_key_type_t link_key_type; 1424 #endif 1425 1426 switch (sm_conn->sm_engine_state){ 1427 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1428 memcpy(setup->sm_local_confirm, hash, 16); 1429 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1430 break; 1431 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1432 // check 1433 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1434 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1435 break; 1436 } 1437 sm_sc_state_after_receiving_random(sm_conn); 1438 break; 1439 case SM_SC_W4_CALCULATE_G2: { 1440 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1441 big_endian_store_32(setup->sm_tk, 12, vab); 1442 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1443 sm_trigger_user_response(sm_conn); 1444 break; 1445 } 1446 case SM_SC_W4_CALCULATE_F5_SALT: 1447 memcpy(setup->sm_t, hash, 16); 1448 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1449 break; 1450 case SM_SC_W4_CALCULATE_F5_MACKEY: 1451 memcpy(setup->sm_mackey, hash, 16); 1452 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1453 break; 1454 case SM_SC_W4_CALCULATE_F5_LTK: 1455 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1456 // Errata Service Release to the Bluetooth Specification: ESR09 1457 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1458 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1459 memcpy(setup->sm_ltk, hash, 16); 1460 memcpy(setup->sm_local_ltk, hash, 16); 1461 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1462 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1463 break; 1464 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1465 memcpy(setup->sm_local_dhkey_check, hash, 16); 1466 if (IS_RESPONDER(sm_conn->sm_role)){ 1467 // responder 1468 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1469 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1470 } else { 1471 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1472 } 1473 } else { 1474 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1475 } 1476 break; 1477 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1478 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1479 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1480 break; 1481 } 1482 if (IS_RESPONDER(sm_conn->sm_role)){ 1483 // responder 1484 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1485 } else { 1486 // initiator 1487 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1488 } 1489 break; 1490 case SM_SC_W4_CALCULATE_H6_ILK: 1491 memcpy(setup->sm_t, hash, 16); 1492 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1493 break; 1494 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1495 #ifdef ENABLE_CLASSIC 1496 reverse_128(hash, setup->sm_t); 1497 link_key_type = sm_conn->sm_connection_authenticated ? 1498 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1499 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1500 if (IS_RESPONDER(sm_conn->sm_role)){ 1501 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1502 } else { 1503 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1504 } 1505 #endif 1506 if (IS_RESPONDER(sm_conn->sm_role)){ 1507 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1508 } else { 1509 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1510 } 1511 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1512 sm_done_for_handle(sm_conn->sm_handle); 1513 break; 1514 default: 1515 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1516 break; 1517 } 1518 sm_run(); 1519 } 1520 1521 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){ 1522 const uint16_t message_len = 65; 1523 sm_cmac_connection = sm_conn; 1524 memcpy(sm_cmac_sc_buffer, u, 32); 1525 memcpy(sm_cmac_sc_buffer+32, v, 32); 1526 sm_cmac_sc_buffer[64] = z; 1527 log_info("f4 key"); 1528 log_info_hexdump(x, 16); 1529 log_info("f4 message"); 1530 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1531 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1532 } 1533 1534 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1535 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1536 static const uint8_t f5_length[] = { 0x01, 0x00}; 1537 1538 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1539 log_info("f5_calculate_salt"); 1540 // calculate salt for f5 1541 const uint16_t message_len = 32; 1542 sm_cmac_connection = sm_conn; 1543 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1544 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1545 } 1546 1547 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){ 1548 const uint16_t message_len = 53; 1549 sm_cmac_connection = sm_conn; 1550 1551 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1552 sm_cmac_sc_buffer[0] = 0; 1553 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1554 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1555 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1556 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1557 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1558 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1559 log_info("f5 key"); 1560 log_info_hexdump(t, 16); 1561 log_info("f5 message for MacKey"); 1562 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1563 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1564 } 1565 1566 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1567 sm_key56_t bd_addr_master, bd_addr_slave; 1568 bd_addr_master[0] = setup->sm_m_addr_type; 1569 bd_addr_slave[0] = setup->sm_s_addr_type; 1570 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1571 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1572 if (IS_RESPONDER(sm_conn->sm_role)){ 1573 // responder 1574 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1575 } else { 1576 // initiator 1577 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1578 } 1579 } 1580 1581 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1582 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1583 const uint16_t message_len = 53; 1584 sm_cmac_connection = sm_conn; 1585 sm_cmac_sc_buffer[0] = 1; 1586 // 1..52 setup before 1587 log_info("f5 key"); 1588 log_info_hexdump(t, 16); 1589 log_info("f5 message for LTK"); 1590 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1591 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1592 } 1593 1594 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1595 f5_ltk(sm_conn, setup->sm_t); 1596 } 1597 1598 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){ 1599 const uint16_t message_len = 65; 1600 sm_cmac_connection = sm_conn; 1601 memcpy(sm_cmac_sc_buffer, n1, 16); 1602 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1603 memcpy(sm_cmac_sc_buffer+32, r, 16); 1604 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1605 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1606 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1607 log_info("f6 key"); 1608 log_info_hexdump(w, 16); 1609 log_info("f6 message"); 1610 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1611 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1612 } 1613 1614 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1615 // - U is 256 bits 1616 // - V is 256 bits 1617 // - X is 128 bits 1618 // - Y is 128 bits 1619 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){ 1620 const uint16_t message_len = 80; 1621 sm_cmac_connection = sm_conn; 1622 memcpy(sm_cmac_sc_buffer, u, 32); 1623 memcpy(sm_cmac_sc_buffer+32, v, 32); 1624 memcpy(sm_cmac_sc_buffer+64, y, 16); 1625 log_info("g2 key"); 1626 log_info_hexdump(x, 16); 1627 log_info("g2 message"); 1628 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1629 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1630 } 1631 1632 static void g2_calculate(sm_connection_t * sm_conn) { 1633 // calc Va if numeric comparison 1634 if (IS_RESPONDER(sm_conn->sm_role)){ 1635 // responder 1636 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1637 } else { 1638 // initiator 1639 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1640 } 1641 } 1642 1643 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1644 uint8_t z = 0; 1645 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1646 // some form of passkey 1647 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1648 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1649 setup->sm_passkey_bit++; 1650 } 1651 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1652 } 1653 1654 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1655 // OOB 1656 if (setup->sm_stk_generation_method == OOB){ 1657 if (IS_RESPONDER(sm_conn->sm_role)){ 1658 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1659 } else { 1660 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1661 } 1662 return; 1663 } 1664 1665 uint8_t z = 0; 1666 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1667 // some form of passkey 1668 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1669 // sm_passkey_bit was increased before sending confirm value 1670 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1671 } 1672 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1673 } 1674 1675 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1676 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1677 1678 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1679 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1680 return; 1681 } else { 1682 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1683 } 1684 } 1685 1686 static void sm_sc_dhkey_calculated(void * arg){ 1687 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1688 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1689 if (sm_conn == NULL) return; 1690 1691 log_info("dhkey"); 1692 log_info_hexdump(&setup->sm_dhkey[0], 32); 1693 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1694 // trigger next step 1695 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1696 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1697 } 1698 sm_run(); 1699 } 1700 1701 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1702 // calculate DHKCheck 1703 sm_key56_t bd_addr_master, bd_addr_slave; 1704 bd_addr_master[0] = setup->sm_m_addr_type; 1705 bd_addr_slave[0] = setup->sm_s_addr_type; 1706 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1707 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1708 uint8_t iocap_a[3]; 1709 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1710 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1711 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1712 uint8_t iocap_b[3]; 1713 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1714 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1715 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1716 if (IS_RESPONDER(sm_conn->sm_role)){ 1717 // responder 1718 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); 1719 } else { 1720 // initiator 1721 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); 1722 } 1723 } 1724 1725 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1726 // validate E = f6() 1727 sm_key56_t bd_addr_master, bd_addr_slave; 1728 bd_addr_master[0] = setup->sm_m_addr_type; 1729 bd_addr_slave[0] = setup->sm_s_addr_type; 1730 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1731 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1732 1733 uint8_t iocap_a[3]; 1734 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1735 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1736 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1737 uint8_t iocap_b[3]; 1738 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1739 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1740 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1741 if (IS_RESPONDER(sm_conn->sm_role)){ 1742 // responder 1743 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); 1744 } else { 1745 // initiator 1746 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); 1747 } 1748 } 1749 1750 1751 // 1752 // Link Key Conversion Function h6 1753 // 1754 // h6(W, keyID) = AES-CMACW(keyID) 1755 // - W is 128 bits 1756 // - keyID is 32 bits 1757 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1758 const uint16_t message_len = 4; 1759 sm_cmac_connection = sm_conn; 1760 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1761 log_info("h6 key"); 1762 log_info_hexdump(w, 16); 1763 log_info("h6 message"); 1764 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1765 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1766 } 1767 1768 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1769 // Errata Service Release to the Bluetooth Specification: ESR09 1770 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1771 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1772 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1773 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1774 } 1775 1776 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1777 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1778 } 1779 1780 #endif 1781 1782 // key management legacy connections: 1783 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1784 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1785 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1786 // - responder reconnects: responder uses LTK receveived from master 1787 1788 // key management secure connections: 1789 // - both devices store same LTK from ECDH key exchange. 1790 1791 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1792 static void sm_load_security_info(sm_connection_t * sm_connection){ 1793 int encryption_key_size; 1794 int authenticated; 1795 int authorized; 1796 int secure_connection; 1797 1798 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1799 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1800 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1801 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); 1802 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1803 sm_connection->sm_connection_authenticated = authenticated; 1804 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1805 sm_connection->sm_connection_sc = secure_connection; 1806 } 1807 #endif 1808 1809 #ifdef ENABLE_LE_PERIPHERAL 1810 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1811 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1812 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1813 // re-establish used key encryption size 1814 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1815 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1816 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1817 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1818 // Legacy paring -> not SC 1819 sm_connection->sm_connection_sc = 0; 1820 log_info("sm: received ltk request with key size %u, authenticated %u", 1821 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1822 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1823 sm_run(); 1824 } 1825 #endif 1826 1827 static void sm_run(void){ 1828 1829 btstack_linked_list_iterator_t it; 1830 1831 // assert that stack has already bootet 1832 if (hci_get_state() != HCI_STATE_WORKING) return; 1833 1834 // assert that we can send at least commands 1835 if (!hci_can_send_command_packet_now()) return; 1836 1837 // pause until IR/ER are ready 1838 if (sm_persistent_keys_random_active) return; 1839 1840 // 1841 // non-connection related behaviour 1842 // 1843 1844 // distributed key generation 1845 switch (dkg_state){ 1846 case DKG_CALC_IRK: 1847 // already busy? 1848 if (sm_aes128_state == SM_AES128_IDLE) { 1849 log_info("DKG_CALC_IRK started"); 1850 // IRK = d1(IR, 1, 0) 1851 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1852 sm_aes128_state = SM_AES128_ACTIVE; 1853 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1854 return; 1855 } 1856 break; 1857 case DKG_CALC_DHK: 1858 // already busy? 1859 if (sm_aes128_state == SM_AES128_IDLE) { 1860 log_info("DKG_CALC_DHK started"); 1861 // DHK = d1(IR, 3, 0) 1862 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1863 sm_aes128_state = SM_AES128_ACTIVE; 1864 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1865 return; 1866 } 1867 break; 1868 default: 1869 break; 1870 } 1871 1872 // random address updates 1873 switch (rau_state){ 1874 case RAU_GET_RANDOM: 1875 rau_state = RAU_W4_RANDOM; 1876 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1877 return; 1878 case RAU_GET_ENC: 1879 // already busy? 1880 if (sm_aes128_state == SM_AES128_IDLE) { 1881 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1882 sm_aes128_state = SM_AES128_ACTIVE; 1883 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1884 return; 1885 } 1886 break; 1887 case RAU_SET_ADDRESS: 1888 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1889 rau_state = RAU_IDLE; 1890 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1891 return; 1892 default: 1893 break; 1894 } 1895 1896 // CSRK Lookup 1897 // -- if csrk lookup ready, find connection that require csrk lookup 1898 if (sm_address_resolution_idle()){ 1899 hci_connections_get_iterator(&it); 1900 while(btstack_linked_list_iterator_has_next(&it)){ 1901 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1902 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1903 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1904 // and start lookup 1905 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); 1906 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1907 break; 1908 } 1909 } 1910 } 1911 1912 // -- if csrk lookup ready, resolved addresses for received addresses 1913 if (sm_address_resolution_idle()) { 1914 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1915 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1916 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1917 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1918 btstack_memory_sm_lookup_entry_free(entry); 1919 } 1920 } 1921 1922 // -- Continue with CSRK device lookup by public or resolvable private address 1923 if (!sm_address_resolution_idle()){ 1924 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1925 while (sm_address_resolution_test < le_device_db_max_count()){ 1926 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1927 bd_addr_t addr; 1928 sm_key_t irk; 1929 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1930 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1931 1932 // skip unused entries 1933 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1934 sm_address_resolution_test++; 1935 continue; 1936 } 1937 1938 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1939 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1940 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1941 break; 1942 } 1943 1944 // if connection type is public, it must be a different one 1945 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1946 sm_address_resolution_test++; 1947 continue; 1948 } 1949 1950 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1951 1952 log_info("LE Device Lookup: calculate AH"); 1953 log_info_key("IRK", irk); 1954 1955 memcpy(sm_aes128_key, irk, 16); 1956 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1957 sm_address_resolution_ah_calculation_active = 1; 1958 sm_aes128_state = SM_AES128_ACTIVE; 1959 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1960 return; 1961 } 1962 1963 if (sm_address_resolution_test >= le_device_db_max_count()){ 1964 log_info("LE Device Lookup: not found"); 1965 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1966 } 1967 } 1968 1969 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1970 switch (sm_sc_oob_state){ 1971 case SM_SC_OOB_W2_CALC_CONFIRM: 1972 if (!sm_cmac_ready()) break; 1973 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1974 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1975 return; 1976 default: 1977 break; 1978 } 1979 #endif 1980 1981 // assert that we can send at least commands - cmd might have been sent by crypto engine 1982 if (!hci_can_send_command_packet_now()) return; 1983 1984 // handle basic actions that don't requires the full context 1985 hci_connections_get_iterator(&it); 1986 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1987 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1988 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1989 switch(sm_connection->sm_engine_state){ 1990 // responder side 1991 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1992 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1993 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1994 return; 1995 1996 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1997 case SM_SC_RECEIVED_LTK_REQUEST: 1998 switch (sm_connection->sm_irk_lookup_state){ 1999 case IRK_LOOKUP_FAILED: 2000 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2001 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2002 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2003 return; 2004 default: 2005 break; 2006 } 2007 break; 2008 #endif 2009 default: 2010 break; 2011 } 2012 } 2013 2014 // 2015 // active connection handling 2016 // -- use loop to handle next connection if lock on setup context is released 2017 2018 while (1) { 2019 2020 // Find connections that requires setup context and make active if no other is locked 2021 hci_connections_get_iterator(&it); 2022 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2023 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2024 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2025 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2026 int done = 1; 2027 int err; 2028 UNUSED(err); 2029 2030 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2031 // assert ec key is ready 2032 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2033 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2034 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2035 sm_ec_generate_new_key(); 2036 } 2037 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2038 continue; 2039 } 2040 } 2041 #endif 2042 2043 switch (sm_connection->sm_engine_state) { 2044 #ifdef ENABLE_LE_PERIPHERAL 2045 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2046 // send packet if possible, 2047 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2048 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2049 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2050 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2051 } else { 2052 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2053 } 2054 // don't lock sxetup context yet 2055 done = 0; 2056 break; 2057 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2058 sm_reset_setup(); 2059 sm_init_setup(sm_connection); 2060 // recover pairing request 2061 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2062 err = sm_stk_generation_init(sm_connection); 2063 2064 #ifdef ENABLE_TESTING_SUPPORT 2065 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2066 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2067 err = test_pairing_failure; 2068 } 2069 #endif 2070 if (err){ 2071 setup->sm_pairing_failed_reason = err; 2072 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2073 break; 2074 } 2075 sm_timeout_start(sm_connection); 2076 // generate random number first, if we need to show passkey 2077 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2078 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); 2079 break; 2080 } 2081 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2082 break; 2083 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2084 sm_reset_setup(); 2085 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2086 break; 2087 2088 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2089 case SM_SC_RECEIVED_LTK_REQUEST: 2090 switch (sm_connection->sm_irk_lookup_state){ 2091 case IRK_LOOKUP_SUCCEEDED: 2092 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2093 // start using context by loading security info 2094 sm_reset_setup(); 2095 sm_load_security_info(sm_connection); 2096 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2097 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2098 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2099 break; 2100 } 2101 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2102 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2103 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2104 // don't lock setup context yet 2105 return; 2106 default: 2107 // just wait until IRK lookup is completed 2108 // don't lock setup context yet 2109 done = 0; 2110 break; 2111 } 2112 break; 2113 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2114 #endif /* ENABLE_LE_PERIPHERAL */ 2115 2116 #ifdef ENABLE_LE_CENTRAL 2117 case SM_INITIATOR_PH0_HAS_LTK: 2118 sm_reset_setup(); 2119 sm_load_security_info(sm_connection); 2120 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2121 break; 2122 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2123 sm_reset_setup(); 2124 sm_init_setup(sm_connection); 2125 sm_timeout_start(sm_connection); 2126 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2127 break; 2128 #endif 2129 2130 default: 2131 done = 0; 2132 break; 2133 } 2134 if (done){ 2135 sm_active_connection_handle = sm_connection->sm_handle; 2136 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); 2137 } 2138 } 2139 2140 // 2141 // active connection handling 2142 // 2143 2144 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2145 2146 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2147 if (!connection) { 2148 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2149 return; 2150 } 2151 2152 // assert that we could send a SM PDU - not needed for all of the following 2153 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2154 log_info("cannot send now, requesting can send now event"); 2155 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2156 return; 2157 } 2158 2159 // send keypress notifications 2160 if (setup->sm_keypress_notification){ 2161 int i; 2162 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2163 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2164 uint8_t action = 0; 2165 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2166 if (flags & (1<<i)){ 2167 int clear_flag = 1; 2168 switch (i){ 2169 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2170 case SM_KEYPRESS_PASSKEY_CLEARED: 2171 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2172 default: 2173 break; 2174 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2175 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2176 num_actions--; 2177 clear_flag = num_actions == 0; 2178 break; 2179 } 2180 if (clear_flag){ 2181 flags &= ~(1<<i); 2182 } 2183 action = i; 2184 break; 2185 } 2186 } 2187 setup->sm_keypress_notification = (num_actions << 5) | flags; 2188 2189 // send keypress notification 2190 uint8_t buffer[2]; 2191 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2192 buffer[1] = action; 2193 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2194 2195 // try 2196 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2197 return; 2198 } 2199 2200 int key_distribution_flags; 2201 UNUSED(key_distribution_flags); 2202 2203 log_info("sm_run: state %u", connection->sm_engine_state); 2204 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2205 log_info("sm_run // cannot send"); 2206 } 2207 switch (connection->sm_engine_state){ 2208 2209 // general 2210 case SM_GENERAL_SEND_PAIRING_FAILED: { 2211 uint8_t buffer[2]; 2212 buffer[0] = SM_CODE_PAIRING_FAILED; 2213 buffer[1] = setup->sm_pairing_failed_reason; 2214 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2215 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2216 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2217 sm_done_for_handle(connection->sm_handle); 2218 break; 2219 } 2220 2221 // responding state 2222 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2223 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2224 if (!sm_cmac_ready()) break; 2225 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2226 sm_sc_calculate_local_confirm(connection); 2227 break; 2228 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2229 if (!sm_cmac_ready()) break; 2230 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2231 sm_sc_calculate_remote_confirm(connection); 2232 break; 2233 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2234 if (!sm_cmac_ready()) break; 2235 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2236 sm_sc_calculate_f6_for_dhkey_check(connection); 2237 break; 2238 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2239 if (!sm_cmac_ready()) break; 2240 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2241 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2242 break; 2243 case SM_SC_W2_CALCULATE_F5_SALT: 2244 if (!sm_cmac_ready()) break; 2245 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2246 f5_calculate_salt(connection); 2247 break; 2248 case SM_SC_W2_CALCULATE_F5_MACKEY: 2249 if (!sm_cmac_ready()) break; 2250 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2251 f5_calculate_mackey(connection); 2252 break; 2253 case SM_SC_W2_CALCULATE_F5_LTK: 2254 if (!sm_cmac_ready()) break; 2255 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2256 f5_calculate_ltk(connection); 2257 break; 2258 case SM_SC_W2_CALCULATE_G2: 2259 if (!sm_cmac_ready()) break; 2260 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2261 g2_calculate(connection); 2262 break; 2263 case SM_SC_W2_CALCULATE_H6_ILK: 2264 if (!sm_cmac_ready()) break; 2265 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2266 h6_calculate_ilk(connection); 2267 break; 2268 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2269 if (!sm_cmac_ready()) break; 2270 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2271 h6_calculate_br_edr_link_key(connection); 2272 break; 2273 #endif 2274 2275 #ifdef ENABLE_LE_CENTRAL 2276 // initiator side 2277 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2278 sm_key_t peer_ltk_flipped; 2279 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2280 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2281 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2282 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2283 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2284 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2285 return; 2286 } 2287 2288 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2289 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2290 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2291 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2292 sm_timeout_reset(connection); 2293 break; 2294 #endif 2295 2296 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2297 2298 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2299 int trigger_user_response = 0; 2300 2301 uint8_t buffer[65]; 2302 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2303 // 2304 reverse_256(&ec_q[0], &buffer[1]); 2305 reverse_256(&ec_q[32], &buffer[33]); 2306 2307 #ifdef ENABLE_TESTING_SUPPORT 2308 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2309 log_info("testing_support: invalidating public key"); 2310 // flip single bit of public key coordinate 2311 buffer[1] ^= 1; 2312 } 2313 #endif 2314 2315 // stk generation method 2316 // passkey entry: notify app to show passkey or to request passkey 2317 switch (setup->sm_stk_generation_method){ 2318 case JUST_WORKS: 2319 case NUMERIC_COMPARISON: 2320 if (IS_RESPONDER(connection->sm_role)){ 2321 // responder 2322 sm_sc_start_calculating_local_confirm(connection); 2323 } else { 2324 // initiator 2325 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2326 } 2327 break; 2328 case PK_INIT_INPUT: 2329 case PK_RESP_INPUT: 2330 case PK_BOTH_INPUT: 2331 // use random TK for display 2332 memcpy(setup->sm_ra, setup->sm_tk, 16); 2333 memcpy(setup->sm_rb, setup->sm_tk, 16); 2334 setup->sm_passkey_bit = 0; 2335 2336 if (IS_RESPONDER(connection->sm_role)){ 2337 // responder 2338 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2339 } else { 2340 // initiator 2341 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2342 } 2343 trigger_user_response = 1; 2344 break; 2345 case OOB: 2346 if (IS_RESPONDER(connection->sm_role)){ 2347 // responder 2348 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2349 } else { 2350 // initiator 2351 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2352 } 2353 break; 2354 } 2355 2356 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2357 sm_timeout_reset(connection); 2358 2359 // trigger user response after sending pdu 2360 if (trigger_user_response){ 2361 sm_trigger_user_response(connection); 2362 } 2363 break; 2364 } 2365 case SM_SC_SEND_CONFIRMATION: { 2366 uint8_t buffer[17]; 2367 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2368 reverse_128(setup->sm_local_confirm, &buffer[1]); 2369 if (IS_RESPONDER(connection->sm_role)){ 2370 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2371 } else { 2372 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2373 } 2374 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2375 sm_timeout_reset(connection); 2376 break; 2377 } 2378 case SM_SC_SEND_PAIRING_RANDOM: { 2379 uint8_t buffer[17]; 2380 buffer[0] = SM_CODE_PAIRING_RANDOM; 2381 reverse_128(setup->sm_local_nonce, &buffer[1]); 2382 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2383 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2384 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2385 if (IS_RESPONDER(connection->sm_role)){ 2386 // responder 2387 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2388 } else { 2389 // initiator 2390 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2391 } 2392 } else { 2393 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2394 if (IS_RESPONDER(connection->sm_role)){ 2395 // responder 2396 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2397 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2398 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2399 } else { 2400 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2401 sm_sc_prepare_dhkey_check(connection); 2402 } 2403 } else { 2404 // initiator 2405 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2406 } 2407 } 2408 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2409 sm_timeout_reset(connection); 2410 break; 2411 } 2412 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2413 uint8_t buffer[17]; 2414 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2415 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2416 2417 if (IS_RESPONDER(connection->sm_role)){ 2418 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2419 } else { 2420 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2421 } 2422 2423 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2424 sm_timeout_reset(connection); 2425 break; 2426 } 2427 2428 #endif 2429 2430 #ifdef ENABLE_LE_PERIPHERAL 2431 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2432 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2433 2434 // start with initiator key dist flags 2435 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2436 2437 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2438 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2439 if (setup->sm_use_secure_connections){ 2440 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2441 } 2442 #endif 2443 // setup in response 2444 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); 2445 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); 2446 2447 // update key distribution after ENC was dropped 2448 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2449 2450 if (setup->sm_use_secure_connections){ 2451 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2452 } else { 2453 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2454 } 2455 2456 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2457 sm_timeout_reset(connection); 2458 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2459 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2460 sm_trigger_user_response(connection); 2461 } 2462 return; 2463 #endif 2464 2465 case SM_PH2_SEND_PAIRING_RANDOM: { 2466 uint8_t buffer[17]; 2467 buffer[0] = SM_CODE_PAIRING_RANDOM; 2468 reverse_128(setup->sm_local_random, &buffer[1]); 2469 if (IS_RESPONDER(connection->sm_role)){ 2470 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2471 } else { 2472 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2473 } 2474 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2475 sm_timeout_reset(connection); 2476 break; 2477 } 2478 2479 case SM_PH2_C1_GET_ENC_A: 2480 // already busy? 2481 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2482 // calculate confirm using aes128 engine - step 1 2483 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); 2484 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2485 sm_aes128_state = SM_AES128_ACTIVE; 2486 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); 2487 break; 2488 2489 case SM_PH2_C1_GET_ENC_C: 2490 // already busy? 2491 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2492 // calculate m_confirm using aes128 engine - step 1 2493 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); 2494 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2495 sm_aes128_state = SM_AES128_ACTIVE; 2496 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); 2497 break; 2498 2499 case SM_PH2_CALC_STK: 2500 // already busy? 2501 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2502 // calculate STK 2503 if (IS_RESPONDER(connection->sm_role)){ 2504 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2505 } else { 2506 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2507 } 2508 connection->sm_engine_state = SM_PH2_W4_STK; 2509 sm_aes128_state = SM_AES128_ACTIVE; 2510 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); 2511 break; 2512 2513 case SM_PH3_Y_GET_ENC: 2514 // already busy? 2515 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2516 // PH3B2 - calculate Y from - enc 2517 // Y = dm(DHK, Rand) 2518 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2519 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2520 sm_aes128_state = SM_AES128_ACTIVE; 2521 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); 2522 break; 2523 2524 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2525 uint8_t buffer[17]; 2526 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2527 reverse_128(setup->sm_local_confirm, &buffer[1]); 2528 if (IS_RESPONDER(connection->sm_role)){ 2529 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2530 } else { 2531 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2532 } 2533 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2534 sm_timeout_reset(connection); 2535 return; 2536 } 2537 #ifdef ENABLE_LE_PERIPHERAL 2538 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2539 sm_key_t stk_flipped; 2540 reverse_128(setup->sm_ltk, stk_flipped); 2541 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2542 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2543 return; 2544 } 2545 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2546 sm_key_t ltk_flipped; 2547 reverse_128(setup->sm_ltk, ltk_flipped); 2548 connection->sm_engine_state = SM_RESPONDER_IDLE; 2549 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2550 sm_done_for_handle(connection->sm_handle); 2551 return; 2552 } 2553 case SM_RESPONDER_PH4_Y_GET_ENC: 2554 // already busy? 2555 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2556 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2557 // Y = dm(DHK, Rand) 2558 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2559 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2560 sm_aes128_state = SM_AES128_ACTIVE; 2561 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); 2562 return; 2563 #endif 2564 #ifdef ENABLE_LE_CENTRAL 2565 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2566 sm_key_t stk_flipped; 2567 reverse_128(setup->sm_ltk, stk_flipped); 2568 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2569 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2570 return; 2571 } 2572 #endif 2573 2574 case SM_PH3_DISTRIBUTE_KEYS: 2575 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2576 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2577 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2578 uint8_t buffer[17]; 2579 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2580 reverse_128(setup->sm_ltk, &buffer[1]); 2581 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2582 sm_timeout_reset(connection); 2583 return; 2584 } 2585 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2586 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2587 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2588 uint8_t buffer[11]; 2589 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2590 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2591 reverse_64(setup->sm_local_rand, &buffer[3]); 2592 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2593 sm_timeout_reset(connection); 2594 return; 2595 } 2596 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2597 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2598 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2599 uint8_t buffer[17]; 2600 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2601 reverse_128(sm_persistent_irk, &buffer[1]); 2602 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2603 sm_timeout_reset(connection); 2604 return; 2605 } 2606 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2607 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2608 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2609 bd_addr_t local_address; 2610 uint8_t buffer[8]; 2611 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2612 switch (gap_random_address_get_mode()){ 2613 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2614 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2615 // public or static random 2616 gap_le_get_own_address(&buffer[1], local_address); 2617 break; 2618 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2619 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2620 // fallback to public 2621 gap_local_bd_addr(local_address); 2622 buffer[1] = 0; 2623 break; 2624 } 2625 reverse_bd_addr(local_address, &buffer[2]); 2626 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2627 sm_timeout_reset(connection); 2628 return; 2629 } 2630 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2631 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2632 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2633 2634 #ifdef ENABLE_LE_SIGNED_WRITE 2635 // hack to reproduce test runs 2636 if (test_use_fixed_local_csrk){ 2637 memset(setup->sm_local_csrk, 0xcc, 16); 2638 } 2639 2640 // store local CSRK 2641 if (setup->sm_le_device_index >= 0){ 2642 log_info("sm: store local CSRK"); 2643 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2644 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2645 } 2646 #endif 2647 2648 uint8_t buffer[17]; 2649 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2650 reverse_128(setup->sm_local_csrk, &buffer[1]); 2651 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2652 sm_timeout_reset(connection); 2653 return; 2654 } 2655 2656 // keys are sent 2657 if (IS_RESPONDER(connection->sm_role)){ 2658 // slave -> receive master keys if any 2659 if (sm_key_distribution_all_received(connection)){ 2660 sm_key_distribution_handle_all_received(connection); 2661 connection->sm_engine_state = SM_RESPONDER_IDLE; 2662 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2663 sm_done_for_handle(connection->sm_handle); 2664 } else { 2665 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2666 } 2667 } else { 2668 // master -> all done 2669 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2670 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2671 sm_done_for_handle(connection->sm_handle); 2672 } 2673 break; 2674 2675 default: 2676 break; 2677 } 2678 2679 // check again if active connection was released 2680 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2681 } 2682 } 2683 2684 // sm_aes128_state stays active 2685 static void sm_handle_encryption_result_enc_a(void *arg){ 2686 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2687 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2688 if (connection == NULL) return; 2689 2690 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2691 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); 2692 } 2693 2694 static void sm_handle_encryption_result_enc_b(void *arg){ 2695 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2696 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2697 if (connection == NULL) return; 2698 2699 sm_aes128_state = SM_AES128_IDLE; 2700 log_info_key("c1!", setup->sm_local_confirm); 2701 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2702 sm_run(); 2703 } 2704 2705 // sm_aes128_state stays active 2706 static void sm_handle_encryption_result_enc_c(void *arg){ 2707 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2708 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2709 if (connection == NULL) return; 2710 2711 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2712 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); 2713 } 2714 2715 static void sm_handle_encryption_result_enc_d(void * arg){ 2716 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2717 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2718 if (connection == NULL) return; 2719 2720 sm_aes128_state = SM_AES128_IDLE; 2721 log_info_key("c1!", sm_aes128_ciphertext); 2722 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2723 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2724 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2725 sm_run(); 2726 return; 2727 } 2728 if (IS_RESPONDER(connection->sm_role)){ 2729 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2730 sm_run(); 2731 } else { 2732 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2733 sm_aes128_state = SM_AES128_ACTIVE; 2734 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); 2735 } 2736 } 2737 2738 static void sm_handle_encryption_result_enc_stk(void *arg){ 2739 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2740 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2741 if (connection == NULL) return; 2742 2743 sm_aes128_state = SM_AES128_IDLE; 2744 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2745 log_info_key("stk", setup->sm_ltk); 2746 if (IS_RESPONDER(connection->sm_role)){ 2747 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2748 } else { 2749 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2750 } 2751 sm_run(); 2752 } 2753 2754 // sm_aes128_state stays active 2755 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2756 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2757 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2758 if (connection == NULL) return; 2759 2760 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2761 log_info_hex16("y", setup->sm_local_y); 2762 // PH3B3 - calculate EDIV 2763 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2764 log_info_hex16("ediv", setup->sm_local_ediv); 2765 // PH3B4 - calculate LTK - enc 2766 // LTK = d1(ER, DIV, 0)) 2767 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2768 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); 2769 } 2770 2771 #ifdef ENABLE_LE_PERIPHERAL 2772 // sm_aes128_state stays active 2773 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2774 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2775 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2776 if (connection == NULL) return; 2777 2778 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2779 log_info_hex16("y", setup->sm_local_y); 2780 2781 // PH3B3 - calculate DIV 2782 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2783 log_info_hex16("ediv", setup->sm_local_ediv); 2784 // PH3B4 - calculate LTK - enc 2785 // LTK = d1(ER, DIV, 0)) 2786 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2787 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); 2788 } 2789 #endif 2790 2791 // sm_aes128_state stays active 2792 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2793 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2794 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2795 if (connection == NULL) return; 2796 2797 log_info_key("ltk", setup->sm_ltk); 2798 // calc CSRK next 2799 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2800 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); 2801 } 2802 2803 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2804 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2805 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2806 if (connection == NULL) return; 2807 2808 sm_aes128_state = SM_AES128_IDLE; 2809 log_info_key("csrk", setup->sm_local_csrk); 2810 if (setup->sm_key_distribution_send_set){ 2811 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2812 } else { 2813 // no keys to send, just continue 2814 if (IS_RESPONDER(connection->sm_role)){ 2815 // slave -> receive master keys 2816 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2817 } else { 2818 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2819 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2820 } else { 2821 // master -> all done 2822 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2823 sm_done_for_handle(connection->sm_handle); 2824 } 2825 } 2826 } 2827 sm_run(); 2828 } 2829 2830 #ifdef ENABLE_LE_PERIPHERAL 2831 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2832 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2833 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2834 if (connection == NULL) return; 2835 2836 sm_aes128_state = SM_AES128_IDLE; 2837 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2838 log_info_key("ltk", setup->sm_ltk); 2839 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2840 sm_run(); 2841 } 2842 #endif 2843 2844 static void sm_handle_encryption_result_address_resolution(void *arg){ 2845 UNUSED(arg); 2846 sm_aes128_state = SM_AES128_IDLE; 2847 sm_address_resolution_ah_calculation_active = 0; 2848 // compare calulated address against connecting device 2849 uint8_t * hash = &sm_aes128_ciphertext[13]; 2850 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2851 log_info("LE Device Lookup: matched resolvable private address"); 2852 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2853 sm_run(); 2854 return; 2855 } 2856 // no match, try next 2857 sm_address_resolution_test++; 2858 sm_run(); 2859 } 2860 2861 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2862 UNUSED(arg); 2863 sm_aes128_state = SM_AES128_IDLE; 2864 log_info_key("irk", sm_persistent_irk); 2865 dkg_state = DKG_CALC_DHK; 2866 sm_run(); 2867 } 2868 2869 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2870 UNUSED(arg); 2871 sm_aes128_state = SM_AES128_IDLE; 2872 log_info_key("dhk", sm_persistent_dhk); 2873 dkg_state = DKG_READY; 2874 sm_run(); 2875 } 2876 2877 static void sm_handle_encryption_result_rau(void *arg){ 2878 UNUSED(arg); 2879 sm_aes128_state = SM_AES128_IDLE; 2880 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2881 rau_state = RAU_SET_ADDRESS; 2882 sm_run(); 2883 } 2884 2885 static void sm_handle_random_result_rau(void * arg){ 2886 UNUSED(arg); 2887 // non-resolvable vs. resolvable 2888 switch (gap_random_adress_type){ 2889 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2890 // resolvable: use random as prand and calc address hash 2891 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2892 sm_random_address[0] &= 0x3f; 2893 sm_random_address[0] |= 0x40; 2894 rau_state = RAU_GET_ENC; 2895 break; 2896 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2897 default: 2898 // "The two most significant bits of the address shall be equal to ‘0’"" 2899 sm_random_address[0] &= 0x3f; 2900 rau_state = RAU_SET_ADDRESS; 2901 break; 2902 } 2903 sm_run(); 2904 } 2905 2906 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2907 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 2908 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2909 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2910 if (connection == NULL) return; 2911 2912 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2913 sm_run(); 2914 } 2915 2916 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 2917 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2918 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2919 if (connection == NULL) return; 2920 2921 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2922 sm_run(); 2923 } 2924 #endif 2925 2926 static void sm_handle_random_result_ph2_random(void * arg){ 2927 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2928 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2929 if (connection == NULL) return; 2930 2931 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2932 sm_run(); 2933 } 2934 2935 static void sm_handle_random_result_ph2_tk(void * arg){ 2936 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2937 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2938 if (connection == NULL) return; 2939 2940 sm_reset_tk(); 2941 uint32_t tk; 2942 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2943 // map random to 0-999999 without speding much cycles on a modulus operation 2944 tk = little_endian_read_32(sm_random_data,0); 2945 tk = tk & 0xfffff; // 1048575 2946 if (tk >= 999999){ 2947 tk = tk - 999999; 2948 } 2949 } else { 2950 // override with pre-defined passkey 2951 tk = sm_fixed_passkey_in_display_role; 2952 } 2953 big_endian_store_32(setup->sm_tk, 12, tk); 2954 if (IS_RESPONDER(connection->sm_role)){ 2955 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2956 } else { 2957 if (setup->sm_use_secure_connections){ 2958 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2959 } else { 2960 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2961 sm_trigger_user_response(connection); 2962 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2963 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2964 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); 2965 } 2966 } 2967 } 2968 sm_run(); 2969 } 2970 2971 static void sm_handle_random_result_ph3_div(void * arg){ 2972 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2973 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2974 if (connection == NULL) return; 2975 2976 // use 16 bit from random value as div 2977 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2978 log_info_hex16("div", setup->sm_local_div); 2979 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2980 sm_run(); 2981 } 2982 2983 static void sm_handle_random_result_ph3_random(void * arg){ 2984 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2985 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2986 if (connection == NULL) return; 2987 2988 reverse_64(sm_random_data, setup->sm_local_rand); 2989 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2990 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2991 // no db for authenticated flag hack: store flag in bit 4 of LSB 2992 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2993 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 2994 } 2995 static void sm_validate_er_ir(void){ 2996 // warn about default ER/IR 2997 int warning = 0; 2998 if (sm_ir_is_default()){ 2999 warning = 1; 3000 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3001 } 3002 if (sm_er_is_default()){ 3003 warning = 1; 3004 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3005 } 3006 if (warning) { 3007 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3008 } 3009 } 3010 3011 static void sm_handle_random_result_ir(void *arg){ 3012 sm_persistent_keys_random_active = 0; 3013 if (arg){ 3014 // key generated, store in tlv 3015 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3016 log_info("Generated IR key. Store in TLV status: %d", status); 3017 } 3018 log_info_key("IR", sm_persistent_ir); 3019 dkg_state = DKG_CALC_IRK; 3020 sm_run(); 3021 } 3022 3023 static void sm_handle_random_result_er(void *arg){ 3024 sm_persistent_keys_random_active = 0; 3025 if (arg){ 3026 // key generated, store in tlv 3027 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3028 log_info("Generated ER key. Store in TLV status: %d", status); 3029 } 3030 log_info_key("ER", sm_persistent_er); 3031 3032 // try load ir 3033 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3034 if (key_size == 16){ 3035 // ok, let's continue 3036 log_info("IR from TLV"); 3037 sm_handle_random_result_ir( NULL ); 3038 } else { 3039 // invalid, generate new random one 3040 sm_persistent_keys_random_active = 1; 3041 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3042 } 3043 } 3044 3045 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3046 3047 UNUSED(channel); // ok: there is no channel 3048 UNUSED(size); // ok: fixed format HCI events 3049 3050 sm_connection_t * sm_conn; 3051 hci_con_handle_t con_handle; 3052 3053 switch (packet_type) { 3054 3055 case HCI_EVENT_PACKET: 3056 switch (hci_event_packet_get_type(packet)) { 3057 3058 case BTSTACK_EVENT_STATE: 3059 // bt stack activated, get started 3060 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3061 log_info("HCI Working!"); 3062 3063 // setup IR/ER with TLV 3064 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3065 if (sm_tlv_impl){ 3066 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3067 if (key_size == 16){ 3068 // ok, let's continue 3069 log_info("ER from TLV"); 3070 sm_handle_random_result_er( NULL ); 3071 } else { 3072 // invalid, generate random one 3073 sm_persistent_keys_random_active = 1; 3074 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3075 } 3076 } else { 3077 sm_validate_er_ir(); 3078 dkg_state = DKG_CALC_IRK; 3079 } 3080 } 3081 break; 3082 3083 case HCI_EVENT_LE_META: 3084 switch (packet[2]) { 3085 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3086 3087 log_info("sm: connected"); 3088 3089 if (packet[3]) return; // connection failed 3090 3091 con_handle = little_endian_read_16(packet, 4); 3092 sm_conn = sm_get_connection_for_handle(con_handle); 3093 if (!sm_conn) break; 3094 3095 sm_conn->sm_handle = con_handle; 3096 sm_conn->sm_role = packet[6]; 3097 sm_conn->sm_peer_addr_type = packet[7]; 3098 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3099 3100 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3101 3102 // reset security properties 3103 sm_conn->sm_connection_encrypted = 0; 3104 sm_conn->sm_connection_authenticated = 0; 3105 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3106 sm_conn->sm_le_db_index = -1; 3107 3108 // prepare CSRK lookup (does not involve setup) 3109 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3110 3111 // just connected -> everything else happens in sm_run() 3112 if (IS_RESPONDER(sm_conn->sm_role)){ 3113 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3114 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3115 if (sm_slave_request_security) { 3116 // request security if requested by app 3117 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3118 } else { 3119 // otherwise, wait for pairing request 3120 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3121 } 3122 } 3123 break; 3124 } else { 3125 // master 3126 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3127 } 3128 break; 3129 3130 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3131 con_handle = little_endian_read_16(packet, 3); 3132 sm_conn = sm_get_connection_for_handle(con_handle); 3133 if (!sm_conn) break; 3134 3135 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3136 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3137 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3138 break; 3139 } 3140 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3141 // PH2 SEND LTK as we need to exchange keys in PH3 3142 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3143 break; 3144 } 3145 3146 // store rand and ediv 3147 reverse_64(&packet[5], sm_conn->sm_local_rand); 3148 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3149 3150 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3151 // potentially stored LTK is from the master 3152 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3153 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3154 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3155 break; 3156 } 3157 // additionally check if remote is in LE Device DB if requested 3158 switch(sm_conn->sm_irk_lookup_state){ 3159 case IRK_LOOKUP_FAILED: 3160 log_info("LTK Request: device not in device db"); 3161 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3162 break; 3163 case IRK_LOOKUP_SUCCEEDED: 3164 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3165 break; 3166 default: 3167 // wait for irk look doen 3168 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3169 break; 3170 } 3171 break; 3172 } 3173 3174 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3175 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3176 #else 3177 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3178 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3179 #endif 3180 break; 3181 3182 default: 3183 break; 3184 } 3185 break; 3186 3187 case HCI_EVENT_ENCRYPTION_CHANGE: 3188 con_handle = little_endian_read_16(packet, 3); 3189 sm_conn = sm_get_connection_for_handle(con_handle); 3190 if (!sm_conn) break; 3191 3192 sm_conn->sm_connection_encrypted = packet[5]; 3193 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3194 sm_conn->sm_actual_encryption_key_size); 3195 log_info("event handler, state %u", sm_conn->sm_engine_state); 3196 3197 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3198 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3199 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3200 // notify client, if pairing was requested before 3201 if (sm_conn->sm_pairing_requested){ 3202 sm_conn->sm_pairing_requested = 0; 3203 if (sm_conn->sm_connection_encrypted){ 3204 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3205 } else { 3206 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3207 } 3208 } 3209 sm_done_for_handle(sm_conn->sm_handle); 3210 break; 3211 } 3212 3213 if (!sm_conn->sm_connection_encrypted) break; 3214 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3215 3216 // continue pairing 3217 switch (sm_conn->sm_engine_state){ 3218 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3219 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3220 sm_done_for_handle(sm_conn->sm_handle); 3221 break; 3222 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3223 if (IS_RESPONDER(sm_conn->sm_role)){ 3224 // slave 3225 if (setup->sm_use_secure_connections){ 3226 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3227 } else { 3228 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); 3229 } 3230 } else { 3231 // master 3232 if (sm_key_distribution_all_received(sm_conn)){ 3233 // skip receiving keys as there are none 3234 sm_key_distribution_handle_all_received(sm_conn); 3235 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); 3236 } else { 3237 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3238 } 3239 } 3240 break; 3241 default: 3242 break; 3243 } 3244 break; 3245 3246 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3247 con_handle = little_endian_read_16(packet, 3); 3248 sm_conn = sm_get_connection_for_handle(con_handle); 3249 if (!sm_conn) break; 3250 3251 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3252 log_info("event handler, state %u", sm_conn->sm_engine_state); 3253 // continue if part of initial pairing 3254 switch (sm_conn->sm_engine_state){ 3255 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3256 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3257 sm_done_for_handle(sm_conn->sm_handle); 3258 break; 3259 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3260 if (IS_RESPONDER(sm_conn->sm_role)){ 3261 // slave 3262 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); 3263 } else { 3264 // master 3265 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3266 } 3267 break; 3268 default: 3269 break; 3270 } 3271 break; 3272 3273 3274 case HCI_EVENT_DISCONNECTION_COMPLETE: 3275 con_handle = little_endian_read_16(packet, 3); 3276 sm_done_for_handle(con_handle); 3277 sm_conn = sm_get_connection_for_handle(con_handle); 3278 if (!sm_conn) break; 3279 3280 // delete stored bonding on disconnect with authentication failure in ph0 3281 if (sm_conn->sm_role == 0 3282 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3283 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3284 le_device_db_remove(sm_conn->sm_le_db_index); 3285 } 3286 3287 // pairing failed, if it was ongoing 3288 switch (sm_conn->sm_engine_state){ 3289 case SM_GENERAL_IDLE: 3290 case SM_INITIATOR_CONNECTED: 3291 case SM_RESPONDER_IDLE: 3292 break; 3293 default: 3294 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3295 break; 3296 } 3297 3298 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3299 sm_conn->sm_handle = 0; 3300 break; 3301 3302 case HCI_EVENT_COMMAND_COMPLETE: 3303 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3304 // set local addr for le device db 3305 bd_addr_t addr; 3306 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3307 le_device_db_set_local_bd_addr(addr); 3308 } 3309 break; 3310 default: 3311 break; 3312 } 3313 break; 3314 default: 3315 break; 3316 } 3317 3318 sm_run(); 3319 } 3320 3321 static inline int sm_calc_actual_encryption_key_size(int other){ 3322 if (other < sm_min_encryption_key_size) return 0; 3323 if (other < sm_max_encryption_key_size) return other; 3324 return sm_max_encryption_key_size; 3325 } 3326 3327 3328 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3329 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3330 switch (method){ 3331 case JUST_WORKS: 3332 case NUMERIC_COMPARISON: 3333 return 1; 3334 default: 3335 return 0; 3336 } 3337 } 3338 // responder 3339 3340 static int sm_passkey_used(stk_generation_method_t method){ 3341 switch (method){ 3342 case PK_RESP_INPUT: 3343 return 1; 3344 default: 3345 return 0; 3346 } 3347 } 3348 3349 static int sm_passkey_entry(stk_generation_method_t method){ 3350 switch (method){ 3351 case PK_RESP_INPUT: 3352 case PK_INIT_INPUT: 3353 case PK_BOTH_INPUT: 3354 return 1; 3355 default: 3356 return 0; 3357 } 3358 } 3359 3360 #endif 3361 3362 /** 3363 * @return ok 3364 */ 3365 static int sm_validate_stk_generation_method(void){ 3366 // check if STK generation method is acceptable by client 3367 switch (setup->sm_stk_generation_method){ 3368 case JUST_WORKS: 3369 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3370 case PK_RESP_INPUT: 3371 case PK_INIT_INPUT: 3372 case PK_BOTH_INPUT: 3373 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3374 case OOB: 3375 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3376 case NUMERIC_COMPARISON: 3377 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3378 default: 3379 return 0; 3380 } 3381 } 3382 3383 // size of complete sm_pdu used to validate input 3384 static const uint8_t sm_pdu_size[] = { 3385 0, // 0x00 invalid opcode 3386 7, // 0x01 pairing request 3387 7, // 0x02 pairing response 3388 17, // 0x03 pairing confirm 3389 17, // 0x04 pairing random 3390 2, // 0x05 pairing failed 3391 17, // 0x06 encryption information 3392 11, // 0x07 master identification 3393 17, // 0x08 identification information 3394 8, // 0x09 identify address information 3395 17, // 0x0a signing information 3396 2, // 0x0b security request 3397 65, // 0x0c pairing public key 3398 17, // 0x0d pairing dhk check 3399 2, // 0x0e keypress notification 3400 }; 3401 3402 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3403 3404 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3405 sm_run(); 3406 } 3407 3408 if (packet_type != SM_DATA_PACKET) return; 3409 if (size == 0) return; 3410 3411 uint8_t sm_pdu_code = packet[0]; 3412 3413 // validate pdu size 3414 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3415 if (sm_pdu_size[sm_pdu_code] != size) return; 3416 3417 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3418 if (!sm_conn) return; 3419 3420 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3421 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3422 sm_done_for_handle(con_handle); 3423 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3424 return; 3425 } 3426 3427 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3428 3429 int err; 3430 UNUSED(err); 3431 3432 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3433 uint8_t buffer[5]; 3434 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3435 buffer[1] = 3; 3436 little_endian_store_16(buffer, 2, con_handle); 3437 buffer[4] = packet[1]; 3438 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3439 return; 3440 } 3441 3442 switch (sm_conn->sm_engine_state){ 3443 3444 // a sm timeout requries a new physical connection 3445 case SM_GENERAL_TIMEOUT: 3446 return; 3447 3448 #ifdef ENABLE_LE_CENTRAL 3449 3450 // Initiator 3451 case SM_INITIATOR_CONNECTED: 3452 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3453 sm_pdu_received_in_wrong_state(sm_conn); 3454 break; 3455 } 3456 3457 // IRK complete? 3458 int have_ltk; 3459 uint8_t ltk[16]; 3460 switch (sm_conn->sm_irk_lookup_state){ 3461 case IRK_LOOKUP_FAILED: 3462 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3463 break; 3464 case IRK_LOOKUP_SUCCEEDED: 3465 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3466 have_ltk = !sm_is_null_key(ltk); 3467 log_info("central: security request - have_ltk %u", have_ltk); 3468 if (have_ltk){ 3469 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3470 } else { 3471 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3472 } 3473 break; 3474 default: 3475 break; 3476 } 3477 3478 // otherwise, store security request 3479 sm_conn->sm_security_request_received = 1; 3480 break; 3481 3482 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3483 // Core 5, Vol 3, Part H, 2.4.6: 3484 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3485 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3486 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3487 log_info("Ignoring Security Request"); 3488 break; 3489 } 3490 3491 // all other pdus are incorrect 3492 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3493 sm_pdu_received_in_wrong_state(sm_conn); 3494 break; 3495 } 3496 3497 // store pairing request 3498 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3499 err = sm_stk_generation_init(sm_conn); 3500 3501 #ifdef ENABLE_TESTING_SUPPORT 3502 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3503 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3504 err = test_pairing_failure; 3505 } 3506 #endif 3507 3508 if (err){ 3509 setup->sm_pairing_failed_reason = err; 3510 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3511 break; 3512 } 3513 3514 // generate random number first, if we need to show passkey 3515 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3516 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); 3517 break; 3518 } 3519 3520 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3521 if (setup->sm_use_secure_connections){ 3522 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3523 if (setup->sm_stk_generation_method == JUST_WORKS){ 3524 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3525 sm_trigger_user_response(sm_conn); 3526 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3527 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3528 } 3529 } else { 3530 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3531 } 3532 break; 3533 } 3534 #endif 3535 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3536 sm_trigger_user_response(sm_conn); 3537 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3538 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3539 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); 3540 } 3541 break; 3542 3543 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3544 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3545 sm_pdu_received_in_wrong_state(sm_conn); 3546 break; 3547 } 3548 3549 // store s_confirm 3550 reverse_128(&packet[1], setup->sm_peer_confirm); 3551 3552 #ifdef ENABLE_TESTING_SUPPORT 3553 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3554 log_info("testing_support: reset confirm value"); 3555 memset(setup->sm_peer_confirm, 0, 16); 3556 } 3557 #endif 3558 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3559 break; 3560 3561 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3562 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3563 sm_pdu_received_in_wrong_state(sm_conn); 3564 break;; 3565 } 3566 3567 // received random value 3568 reverse_128(&packet[1], setup->sm_peer_random); 3569 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3570 break; 3571 #endif 3572 3573 #ifdef ENABLE_LE_PERIPHERAL 3574 // Responder 3575 case SM_RESPONDER_IDLE: 3576 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3577 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3578 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3579 sm_pdu_received_in_wrong_state(sm_conn); 3580 break;; 3581 } 3582 3583 // store pairing request 3584 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3585 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3586 break; 3587 #endif 3588 3589 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3590 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3591 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3592 sm_pdu_received_in_wrong_state(sm_conn); 3593 break; 3594 } 3595 3596 // store public key for DH Key calculation 3597 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3598 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3599 3600 // validate public key 3601 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3602 if (err){ 3603 log_error("sm: peer public key invalid %x", err); 3604 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3605 break; 3606 } 3607 3608 // start calculating dhkey 3609 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); 3610 3611 3612 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3613 if (IS_RESPONDER(sm_conn->sm_role)){ 3614 // responder 3615 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3616 } else { 3617 // initiator 3618 // stk generation method 3619 // passkey entry: notify app to show passkey or to request passkey 3620 switch (setup->sm_stk_generation_method){ 3621 case JUST_WORKS: 3622 case NUMERIC_COMPARISON: 3623 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3624 break; 3625 case PK_RESP_INPUT: 3626 sm_sc_start_calculating_local_confirm(sm_conn); 3627 break; 3628 case PK_INIT_INPUT: 3629 case PK_BOTH_INPUT: 3630 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3631 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3632 break; 3633 } 3634 sm_sc_start_calculating_local_confirm(sm_conn); 3635 break; 3636 case OOB: 3637 // generate Nx 3638 log_info("Generate Na"); 3639 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3640 break; 3641 } 3642 } 3643 break; 3644 3645 case SM_SC_W4_CONFIRMATION: 3646 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3647 sm_pdu_received_in_wrong_state(sm_conn); 3648 break; 3649 } 3650 // received confirm value 3651 reverse_128(&packet[1], setup->sm_peer_confirm); 3652 3653 #ifdef ENABLE_TESTING_SUPPORT 3654 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3655 log_info("testing_support: reset confirm value"); 3656 memset(setup->sm_peer_confirm, 0, 16); 3657 } 3658 #endif 3659 if (IS_RESPONDER(sm_conn->sm_role)){ 3660 // responder 3661 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3662 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3663 // still waiting for passkey 3664 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3665 break; 3666 } 3667 } 3668 sm_sc_start_calculating_local_confirm(sm_conn); 3669 } else { 3670 // initiator 3671 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3672 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3673 } else { 3674 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3675 } 3676 } 3677 break; 3678 3679 case SM_SC_W4_PAIRING_RANDOM: 3680 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3681 sm_pdu_received_in_wrong_state(sm_conn); 3682 break; 3683 } 3684 3685 // received random value 3686 reverse_128(&packet[1], setup->sm_peer_nonce); 3687 3688 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3689 // only check for JUST WORK/NC in initiator role OR passkey entry 3690 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3691 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3692 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3693 break; 3694 } 3695 3696 // OOB 3697 if (setup->sm_stk_generation_method == OOB){ 3698 3699 // setup local random, set to zero if remote did not receive our data 3700 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3701 if (IS_RESPONDER(sm_conn->sm_role)){ 3702 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3703 log_info("Reset rb as A does not have OOB data"); 3704 memset(setup->sm_rb, 0, 16); 3705 } else { 3706 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3707 log_info("Use stored rb"); 3708 log_info_hexdump(setup->sm_rb, 16); 3709 } 3710 } else { 3711 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3712 log_info("Reset ra as B does not have OOB data"); 3713 memset(setup->sm_ra, 0, 16); 3714 } else { 3715 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3716 log_info("Use stored ra"); 3717 log_info_hexdump(setup->sm_ra, 16); 3718 } 3719 } 3720 3721 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3722 if (setup->sm_have_oob_data){ 3723 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3724 break; 3725 } 3726 } 3727 3728 // TODO: we only get here for Responder role with JW/NC 3729 sm_sc_state_after_receiving_random(sm_conn); 3730 break; 3731 3732 case SM_SC_W2_CALCULATE_G2: 3733 case SM_SC_W4_CALCULATE_G2: 3734 case SM_SC_W4_CALCULATE_DHKEY: 3735 case SM_SC_W2_CALCULATE_F5_SALT: 3736 case SM_SC_W4_CALCULATE_F5_SALT: 3737 case SM_SC_W2_CALCULATE_F5_MACKEY: 3738 case SM_SC_W4_CALCULATE_F5_MACKEY: 3739 case SM_SC_W2_CALCULATE_F5_LTK: 3740 case SM_SC_W4_CALCULATE_F5_LTK: 3741 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3742 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3743 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3744 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3745 sm_pdu_received_in_wrong_state(sm_conn); 3746 break; 3747 } 3748 // store DHKey Check 3749 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3750 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3751 3752 // have we been only waiting for dhkey check command? 3753 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3754 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3755 } 3756 break; 3757 #endif 3758 3759 #ifdef ENABLE_LE_PERIPHERAL 3760 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3761 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3762 sm_pdu_received_in_wrong_state(sm_conn); 3763 break; 3764 } 3765 3766 // received confirm value 3767 reverse_128(&packet[1], setup->sm_peer_confirm); 3768 3769 #ifdef ENABLE_TESTING_SUPPORT 3770 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3771 log_info("testing_support: reset confirm value"); 3772 memset(setup->sm_peer_confirm, 0, 16); 3773 } 3774 #endif 3775 // notify client to hide shown passkey 3776 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3777 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3778 } 3779 3780 // handle user cancel pairing? 3781 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3782 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3783 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3784 break; 3785 } 3786 3787 // wait for user action? 3788 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3789 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3790 break; 3791 } 3792 3793 // calculate and send local_confirm 3794 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); 3795 break; 3796 3797 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3798 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3799 sm_pdu_received_in_wrong_state(sm_conn); 3800 break;; 3801 } 3802 3803 // received random value 3804 reverse_128(&packet[1], setup->sm_peer_random); 3805 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3806 break; 3807 #endif 3808 3809 case SM_PH3_RECEIVE_KEYS: 3810 switch(sm_pdu_code){ 3811 case SM_CODE_ENCRYPTION_INFORMATION: 3812 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3813 reverse_128(&packet[1], setup->sm_peer_ltk); 3814 break; 3815 3816 case SM_CODE_MASTER_IDENTIFICATION: 3817 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3818 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3819 reverse_64(&packet[3], setup->sm_peer_rand); 3820 break; 3821 3822 case SM_CODE_IDENTITY_INFORMATION: 3823 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3824 reverse_128(&packet[1], setup->sm_peer_irk); 3825 break; 3826 3827 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3828 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3829 setup->sm_peer_addr_type = packet[1]; 3830 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3831 break; 3832 3833 case SM_CODE_SIGNING_INFORMATION: 3834 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3835 reverse_128(&packet[1], setup->sm_peer_csrk); 3836 break; 3837 default: 3838 // Unexpected PDU 3839 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3840 break; 3841 } 3842 // done with key distribution? 3843 if (sm_key_distribution_all_received(sm_conn)){ 3844 3845 sm_key_distribution_handle_all_received(sm_conn); 3846 3847 if (IS_RESPONDER(sm_conn->sm_role)){ 3848 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3849 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3850 } else { 3851 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3852 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3853 sm_done_for_handle(sm_conn->sm_handle); 3854 } 3855 } else { 3856 if (setup->sm_use_secure_connections){ 3857 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3858 } else { 3859 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); 3860 } 3861 } 3862 } 3863 break; 3864 default: 3865 // Unexpected PDU 3866 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3867 break; 3868 } 3869 3870 // try to send preparared packet 3871 sm_run(); 3872 } 3873 3874 // Security Manager Client API 3875 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3876 sm_get_oob_data = get_oob_data_callback; 3877 } 3878 3879 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)){ 3880 sm_get_sc_oob_data = get_sc_oob_data_callback; 3881 } 3882 3883 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3884 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3885 } 3886 3887 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3888 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3889 } 3890 3891 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3892 sm_min_encryption_key_size = min_size; 3893 sm_max_encryption_key_size = max_size; 3894 } 3895 3896 void sm_set_authentication_requirements(uint8_t auth_req){ 3897 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3898 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3899 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3900 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3901 } 3902 #endif 3903 sm_auth_req = auth_req; 3904 } 3905 3906 void sm_set_io_capabilities(io_capability_t io_capability){ 3907 sm_io_capabilities = io_capability; 3908 } 3909 3910 #ifdef ENABLE_LE_PERIPHERAL 3911 void sm_set_request_security(int enable){ 3912 sm_slave_request_security = enable; 3913 } 3914 #endif 3915 3916 void sm_set_er(sm_key_t er){ 3917 memcpy(sm_persistent_er, er, 16); 3918 } 3919 3920 void sm_set_ir(sm_key_t ir){ 3921 memcpy(sm_persistent_ir, ir, 16); 3922 } 3923 3924 // Testing support only 3925 void sm_test_set_irk(sm_key_t irk){ 3926 memcpy(sm_persistent_irk, irk, 16); 3927 dkg_state = DKG_CALC_DHK; 3928 } 3929 3930 void sm_test_use_fixed_local_csrk(void){ 3931 test_use_fixed_local_csrk = 1; 3932 } 3933 3934 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3935 static void sm_ec_generated(void * arg){ 3936 UNUSED(arg); 3937 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3938 // trigger pairing if pending for ec key 3939 sm_run(); 3940 } 3941 static void sm_ec_generate_new_key(void){ 3942 log_info("sm: generate new ec key"); 3943 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3944 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3945 } 3946 #endif 3947 3948 #ifdef ENABLE_TESTING_SUPPORT 3949 void sm_test_set_pairing_failure(int reason){ 3950 test_pairing_failure = reason; 3951 } 3952 #endif 3953 3954 void sm_init(void){ 3955 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3956 sm_er_ir_set_default(); 3957 3958 // defaults 3959 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3960 | SM_STK_GENERATION_METHOD_OOB 3961 | SM_STK_GENERATION_METHOD_PASSKEY 3962 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3963 3964 sm_max_encryption_key_size = 16; 3965 sm_min_encryption_key_size = 7; 3966 3967 sm_fixed_passkey_in_display_role = 0xffffffff; 3968 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3969 3970 #ifdef USE_CMAC_ENGINE 3971 sm_cmac_active = 0; 3972 #endif 3973 dkg_state = DKG_W4_WORKING; 3974 rau_state = RAU_IDLE; 3975 sm_aes128_state = SM_AES128_IDLE; 3976 sm_address_resolution_test = -1; // no private address to resolve yet 3977 sm_address_resolution_ah_calculation_active = 0; 3978 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3979 sm_address_resolution_general_queue = NULL; 3980 3981 gap_random_adress_update_period = 15 * 60 * 1000L; 3982 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3983 3984 test_use_fixed_local_csrk = 0; 3985 3986 // register for HCI Events from HCI 3987 hci_event_callback_registration.callback = &sm_event_packet_handler; 3988 hci_add_event_handler(&hci_event_callback_registration); 3989 3990 // 3991 btstack_crypto_init(); 3992 3993 // init le_device_db 3994 le_device_db_init(); 3995 3996 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3997 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3998 3999 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4000 sm_ec_generate_new_key(); 4001 #endif 4002 } 4003 4004 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4005 sm_fixed_passkey_in_display_role = passkey; 4006 } 4007 4008 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4009 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4010 } 4011 4012 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4013 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4014 if (!hci_con) return NULL; 4015 return &hci_con->sm_connection; 4016 } 4017 4018 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4019 switch (sm_conn->sm_engine_state){ 4020 case SM_GENERAL_IDLE: 4021 case SM_RESPONDER_IDLE: 4022 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4023 sm_run(); 4024 break; 4025 default: 4026 break; 4027 } 4028 } 4029 4030 /** 4031 * @brief Trigger Security Request 4032 */ 4033 void sm_send_security_request(hci_con_handle_t con_handle){ 4034 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4035 if (!sm_conn) return; 4036 sm_send_security_request_for_connection(sm_conn); 4037 } 4038 4039 // request pairing 4040 void sm_request_pairing(hci_con_handle_t con_handle){ 4041 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4042 if (!sm_conn) return; // wrong connection 4043 4044 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4045 if (IS_RESPONDER(sm_conn->sm_role)){ 4046 sm_send_security_request_for_connection(sm_conn); 4047 } else { 4048 // used as a trigger to start central/master/initiator security procedures 4049 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4050 uint8_t ltk[16]; 4051 switch (sm_conn->sm_irk_lookup_state){ 4052 case IRK_LOOKUP_SUCCEEDED: 4053 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4054 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4055 log_info("have ltk %u", !sm_is_null_key(ltk)); 4056 // trigger 'pairing complete' event on encryption change 4057 sm_conn->sm_pairing_requested = 1; 4058 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4059 break; 4060 #endif 4061 /* explicit fall-through */ 4062 4063 case IRK_LOOKUP_FAILED: 4064 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4065 break; 4066 default: 4067 log_info("irk lookup pending"); 4068 sm_conn->sm_pairing_requested = 1; 4069 break; 4070 } 4071 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4072 sm_conn->sm_pairing_requested = 1; 4073 } 4074 } 4075 sm_run(); 4076 } 4077 4078 // called by client app on authorization request 4079 void sm_authorization_decline(hci_con_handle_t con_handle){ 4080 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4081 if (!sm_conn) return; // wrong connection 4082 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4083 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4084 } 4085 4086 void sm_authorization_grant(hci_con_handle_t con_handle){ 4087 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4088 if (!sm_conn) return; // wrong connection 4089 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4090 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4091 } 4092 4093 // GAP Bonding API 4094 4095 void sm_bonding_decline(hci_con_handle_t con_handle){ 4096 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4097 if (!sm_conn) return; // wrong connection 4098 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4099 log_info("decline, state %u", sm_conn->sm_engine_state); 4100 switch(sm_conn->sm_engine_state){ 4101 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4102 case SM_SC_W4_USER_RESPONSE: 4103 case SM_SC_W4_CONFIRMATION: 4104 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4105 #endif 4106 case SM_PH1_W4_USER_RESPONSE: 4107 switch (setup->sm_stk_generation_method){ 4108 case PK_RESP_INPUT: 4109 case PK_INIT_INPUT: 4110 case PK_BOTH_INPUT: 4111 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4112 break; 4113 case NUMERIC_COMPARISON: 4114 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4115 break; 4116 case JUST_WORKS: 4117 case OOB: 4118 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4119 break; 4120 } 4121 break; 4122 default: 4123 break; 4124 } 4125 sm_run(); 4126 } 4127 4128 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4129 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4130 if (!sm_conn) return; // wrong connection 4131 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4132 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4133 if (setup->sm_use_secure_connections){ 4134 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4135 } else { 4136 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); 4137 } 4138 } 4139 4140 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4141 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4142 sm_sc_prepare_dhkey_check(sm_conn); 4143 } 4144 #endif 4145 4146 sm_run(); 4147 } 4148 4149 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4150 // for now, it's the same 4151 sm_just_works_confirm(con_handle); 4152 } 4153 4154 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4155 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4156 if (!sm_conn) return; // wrong connection 4157 sm_reset_tk(); 4158 big_endian_store_32(setup->sm_tk, 12, passkey); 4159 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4160 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4161 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); 4162 } 4163 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4164 memcpy(setup->sm_ra, setup->sm_tk, 16); 4165 memcpy(setup->sm_rb, setup->sm_tk, 16); 4166 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4167 sm_sc_start_calculating_local_confirm(sm_conn); 4168 } 4169 #endif 4170 sm_run(); 4171 } 4172 4173 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4174 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4175 if (!sm_conn) return; // wrong connection 4176 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4177 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4178 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4179 switch (action){ 4180 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4181 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4182 flags |= (1 << action); 4183 break; 4184 case SM_KEYPRESS_PASSKEY_CLEARED: 4185 // clear counter, keypress & erased flags + set passkey cleared 4186 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4187 break; 4188 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4189 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4190 // erase actions queued 4191 num_actions--; 4192 if (num_actions == 0){ 4193 // clear counter, keypress & erased flags 4194 flags &= 0x19; 4195 } 4196 break; 4197 } 4198 num_actions++; 4199 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4200 break; 4201 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4202 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4203 // enter actions queued 4204 num_actions--; 4205 if (num_actions == 0){ 4206 // clear counter, keypress & erased flags 4207 flags &= 0x19; 4208 } 4209 break; 4210 } 4211 num_actions++; 4212 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4213 break; 4214 default: 4215 break; 4216 } 4217 setup->sm_keypress_notification = (num_actions << 5) | flags; 4218 sm_run(); 4219 } 4220 4221 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4222 static void sm_handle_random_result_oob(void * arg){ 4223 UNUSED(arg); 4224 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4225 sm_run(); 4226 } 4227 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4228 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4229 sm_sc_oob_callback = callback; 4230 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4231 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4232 return 0; 4233 } 4234 #endif 4235 4236 /** 4237 * @brief Get Identity Resolving state 4238 * @param con_handle 4239 * @return irk_lookup_state_t 4240 */ 4241 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4242 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4243 if (!sm_conn) return IRK_LOOKUP_IDLE; 4244 return sm_conn->sm_irk_lookup_state; 4245 } 4246 4247 /** 4248 * @brief Identify device in LE Device DB 4249 * @param handle 4250 * @returns index from le_device_db or -1 if not found/identified 4251 */ 4252 int sm_le_device_index(hci_con_handle_t con_handle ){ 4253 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4254 if (!sm_conn) return -1; 4255 return sm_conn->sm_le_db_index; 4256 } 4257 4258 static int gap_random_address_type_requires_updates(void){ 4259 switch (gap_random_adress_type){ 4260 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4261 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4262 return 0; 4263 default: 4264 return 1; 4265 } 4266 } 4267 4268 static uint8_t own_address_type(void){ 4269 switch (gap_random_adress_type){ 4270 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4271 return BD_ADDR_TYPE_LE_PUBLIC; 4272 default: 4273 return BD_ADDR_TYPE_LE_RANDOM; 4274 } 4275 } 4276 4277 // GAP LE API 4278 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4279 gap_random_address_update_stop(); 4280 gap_random_adress_type = random_address_type; 4281 hci_le_set_own_address_type(own_address_type()); 4282 if (!gap_random_address_type_requires_updates()) return; 4283 gap_random_address_update_start(); 4284 gap_random_address_trigger(); 4285 } 4286 4287 gap_random_address_type_t gap_random_address_get_mode(void){ 4288 return gap_random_adress_type; 4289 } 4290 4291 void gap_random_address_set_update_period(int period_ms){ 4292 gap_random_adress_update_period = period_ms; 4293 if (!gap_random_address_type_requires_updates()) return; 4294 gap_random_address_update_stop(); 4295 gap_random_address_update_start(); 4296 } 4297 4298 void gap_random_address_set(bd_addr_t addr){ 4299 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4300 memcpy(sm_random_address, addr, 6); 4301 rau_state = RAU_SET_ADDRESS; 4302 sm_run(); 4303 } 4304 4305 #ifdef ENABLE_LE_PERIPHERAL 4306 /* 4307 * @brief Set Advertisement Paramters 4308 * @param adv_int_min 4309 * @param adv_int_max 4310 * @param adv_type 4311 * @param direct_address_type 4312 * @param direct_address 4313 * @param channel_map 4314 * @param filter_policy 4315 * 4316 * @note own_address_type is used from gap_random_address_set_mode 4317 */ 4318 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4319 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4320 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4321 direct_address_typ, direct_address, channel_map, filter_policy); 4322 } 4323 #endif 4324 4325 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4326 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4327 // wrong connection 4328 if (!sm_conn) return 0; 4329 // already encrypted 4330 if (sm_conn->sm_connection_encrypted) return 0; 4331 // only central can re-encrypt 4332 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4333 // irk status? 4334 switch(sm_conn->sm_irk_lookup_state){ 4335 case IRK_LOOKUP_FAILED: 4336 // done, cannot setup encryption 4337 return 0; 4338 case IRK_LOOKUP_SUCCEEDED: 4339 break; 4340 default: 4341 // IR Lookup pending 4342 return 1; 4343 } 4344 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4345 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4346 } 4347