1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_crypto.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "btstack_tlv.h" 53 #include "gap.h" 54 #include "hci.h" 55 #include "hci_dump.h" 56 #include "l2cap.h" 57 58 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 59 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 60 #endif 61 62 // assert SM Public Key can be sent/received 63 #ifdef ENABLE_LE_SECURE_CONNECTIONS 64 #if HCI_ACL_PAYLOAD_SIZE < 69 65 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 66 #endif 67 #endif 68 69 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 70 #define IS_RESPONDER(role) (role) 71 #else 72 #ifdef ENABLE_LE_CENTRAL 73 // only central - never responder (avoid 'unused variable' warnings) 74 #define IS_RESPONDER(role) (0 && role) 75 #else 76 // only peripheral - always responder (avoid 'unused variable' warnings) 77 #define IS_RESPONDER(role) (1 || role) 78 #endif 79 #endif 80 81 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 82 #define USE_CMAC_ENGINE 83 #endif 84 85 #define BTSTACK_TAG32(A,B,C,D) ((A << 24) | (B << 16) | (C << 8) | D) 86 87 // 88 // SM internal types and globals 89 // 90 91 typedef enum { 92 DKG_W4_WORKING, 93 DKG_CALC_IRK, 94 DKG_CALC_DHK, 95 DKG_READY 96 } derived_key_generation_t; 97 98 typedef enum { 99 RAU_IDLE, 100 RAU_GET_RANDOM, 101 RAU_W4_RANDOM, 102 RAU_GET_ENC, 103 RAU_W4_ENC, 104 RAU_SET_ADDRESS, 105 } random_address_update_t; 106 107 typedef enum { 108 CMAC_IDLE, 109 CMAC_CALC_SUBKEYS, 110 CMAC_W4_SUBKEYS, 111 CMAC_CALC_MI, 112 CMAC_W4_MI, 113 CMAC_CALC_MLAST, 114 CMAC_W4_MLAST 115 } cmac_state_t; 116 117 typedef enum { 118 JUST_WORKS, 119 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 120 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 121 PK_BOTH_INPUT, // Only input on both, both input PK 122 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 123 OOB // OOB available on one (SC) or both sides (legacy) 124 } stk_generation_method_t; 125 126 typedef enum { 127 SM_USER_RESPONSE_IDLE, 128 SM_USER_RESPONSE_PENDING, 129 SM_USER_RESPONSE_CONFIRM, 130 SM_USER_RESPONSE_PASSKEY, 131 SM_USER_RESPONSE_DECLINE 132 } sm_user_response_t; 133 134 typedef enum { 135 SM_AES128_IDLE, 136 SM_AES128_ACTIVE 137 } sm_aes128_state_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_IDLE, 141 ADDRESS_RESOLUTION_GENERAL, 142 ADDRESS_RESOLUTION_FOR_CONNECTION, 143 } address_resolution_mode_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_SUCEEDED, 147 ADDRESS_RESOLUTION_FAILED, 148 } address_resolution_event_t; 149 150 typedef enum { 151 EC_KEY_GENERATION_IDLE, 152 EC_KEY_GENERATION_ACTIVE, 153 EC_KEY_GENERATION_DONE, 154 } ec_key_generation_state_t; 155 156 typedef enum { 157 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 158 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 159 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 160 } sm_state_var_t; 161 162 typedef enum { 163 SM_SC_OOB_IDLE, 164 SM_SC_OOB_W4_RANDOM, 165 SM_SC_OOB_W2_CALC_CONFIRM, 166 SM_SC_OOB_W4_CONFIRM, 167 } sm_sc_oob_state_t; 168 169 typedef uint8_t sm_key24_t[3]; 170 typedef uint8_t sm_key56_t[7]; 171 typedef uint8_t sm_key256_t[32]; 172 173 // 174 // GLOBAL DATA 175 // 176 177 static uint8_t test_use_fixed_local_csrk; 178 179 #ifdef ENABLE_TESTING_SUPPORT 180 static uint8_t test_pairing_failure; 181 #endif 182 183 // configuration 184 static uint8_t sm_accepted_stk_generation_methods; 185 static uint8_t sm_max_encryption_key_size; 186 static uint8_t sm_min_encryption_key_size; 187 static uint8_t sm_auth_req = 0; 188 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 189 static uint8_t sm_slave_request_security; 190 static uint32_t sm_fixed_passkey_in_display_role; 191 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 192 193 #ifdef ENABLE_LE_SECURE_CONNECTIONS 194 static uint8_t sm_sc_oob_random[16]; 195 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 196 static sm_sc_oob_state_t sm_sc_oob_state; 197 #endif 198 199 200 static uint8_t sm_persistent_keys_random_active; 201 static const btstack_tlv_t * sm_tlv_impl; 202 static void * sm_tlv_context; 203 204 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 205 static sm_key_t sm_persistent_er; 206 static sm_key_t sm_persistent_ir; 207 208 // derived from sm_persistent_ir 209 static sm_key_t sm_persistent_dhk; 210 static sm_key_t sm_persistent_irk; 211 static derived_key_generation_t dkg_state; 212 213 // derived from sm_persistent_er 214 // .. 215 216 // random address update 217 static random_address_update_t rau_state; 218 static bd_addr_t sm_random_address; 219 220 #ifdef USE_CMAC_ENGINE 221 // CMAC Calculation: General 222 static btstack_crypto_aes128_cmac_t sm_cmac_request; 223 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 224 static uint8_t sm_cmac_active; 225 static uint8_t sm_cmac_hash[16]; 226 #endif 227 228 // CMAC for ATT Signed Writes 229 #ifdef ENABLE_LE_SIGNED_WRITE 230 static uint16_t sm_cmac_signed_write_message_len; 231 static uint8_t sm_cmac_signed_write_header[3]; 232 static const uint8_t * sm_cmac_signed_write_message; 233 static uint8_t sm_cmac_signed_write_sign_counter[4]; 234 #endif 235 236 // CMAC for Secure Connection functions 237 #ifdef ENABLE_LE_SECURE_CONNECTIONS 238 static sm_connection_t * sm_cmac_connection; 239 static uint8_t sm_cmac_sc_buffer[80]; 240 #endif 241 242 // resolvable private address lookup / CSRK calculation 243 static int sm_address_resolution_test; 244 static int sm_address_resolution_ah_calculation_active; 245 static uint8_t sm_address_resolution_addr_type; 246 static bd_addr_t sm_address_resolution_address; 247 static void * sm_address_resolution_context; 248 static address_resolution_mode_t sm_address_resolution_mode; 249 static btstack_linked_list_t sm_address_resolution_general_queue; 250 251 // aes128 crypto engine. 252 static sm_aes128_state_t sm_aes128_state; 253 254 // crypto 255 static btstack_crypto_random_t sm_crypto_random_request; 256 static btstack_crypto_aes128_t sm_crypto_aes128_request; 257 #ifdef ENABLE_LE_SECURE_CONNECTIONS 258 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 259 static btstack_crypto_random_t sm_crypto_random_oob_request; 260 #endif 261 262 // temp storage for random data 263 static uint8_t sm_random_data[8]; 264 static uint8_t sm_aes128_key[16]; 265 static uint8_t sm_aes128_plaintext[16]; 266 static uint8_t sm_aes128_ciphertext[16]; 267 268 // to receive hci events 269 static btstack_packet_callback_registration_t hci_event_callback_registration; 270 271 /* to dispatch sm event */ 272 static btstack_linked_list_t sm_event_handlers; 273 274 // LE Secure Connections 275 #ifdef ENABLE_LE_SECURE_CONNECTIONS 276 static ec_key_generation_state_t ec_key_generation_state; 277 static uint8_t ec_q[64]; 278 #endif 279 280 // 281 // Volume 3, Part H, Chapter 24 282 // "Security shall be initiated by the Security Manager in the device in the master role. 283 // The device in the slave role shall be the responding device." 284 // -> master := initiator, slave := responder 285 // 286 287 // data needed for security setup 288 typedef struct sm_setup_context { 289 290 btstack_timer_source_t sm_timeout; 291 292 // used in all phases 293 uint8_t sm_pairing_failed_reason; 294 295 // user response, (Phase 1 and/or 2) 296 uint8_t sm_user_response; 297 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 298 299 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 300 uint8_t sm_key_distribution_send_set; 301 uint8_t sm_key_distribution_sent_set; 302 uint8_t sm_key_distribution_received_set; 303 304 // Phase 2 (Pairing over SMP) 305 stk_generation_method_t sm_stk_generation_method; 306 sm_key_t sm_tk; 307 uint8_t sm_have_oob_data; 308 uint8_t sm_use_secure_connections; 309 310 sm_key_t sm_c1_t3_value; // c1 calculation 311 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 312 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 313 sm_key_t sm_local_random; 314 sm_key_t sm_local_confirm; 315 sm_key_t sm_peer_random; 316 sm_key_t sm_peer_confirm; 317 uint8_t sm_m_addr_type; // address and type can be removed 318 uint8_t sm_s_addr_type; // '' 319 bd_addr_t sm_m_address; // '' 320 bd_addr_t sm_s_address; // '' 321 sm_key_t sm_ltk; 322 323 uint8_t sm_state_vars; 324 #ifdef ENABLE_LE_SECURE_CONNECTIONS 325 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 326 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 327 sm_key_t sm_local_nonce; // might be combined with sm_local_random 328 sm_key_t sm_dhkey; 329 sm_key_t sm_peer_dhkey_check; 330 sm_key_t sm_local_dhkey_check; 331 sm_key_t sm_ra; 332 sm_key_t sm_rb; 333 sm_key_t sm_t; // used for f5 and h6 334 sm_key_t sm_mackey; 335 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 336 #endif 337 338 // Phase 3 339 340 // key distribution, we generate 341 uint16_t sm_local_y; 342 uint16_t sm_local_div; 343 uint16_t sm_local_ediv; 344 uint8_t sm_local_rand[8]; 345 sm_key_t sm_local_ltk; 346 sm_key_t sm_local_csrk; 347 sm_key_t sm_local_irk; 348 // sm_local_address/addr_type not needed 349 350 // key distribution, received from peer 351 uint16_t sm_peer_y; 352 uint16_t sm_peer_div; 353 uint16_t sm_peer_ediv; 354 uint8_t sm_peer_rand[8]; 355 sm_key_t sm_peer_ltk; 356 sm_key_t sm_peer_irk; 357 sm_key_t sm_peer_csrk; 358 uint8_t sm_peer_addr_type; 359 bd_addr_t sm_peer_address; 360 #ifdef ENABLE_LE_SIGNED_WRITE 361 int sm_le_device_index; 362 #endif 363 364 } sm_setup_context_t; 365 366 // 367 static sm_setup_context_t the_setup; 368 static sm_setup_context_t * setup = &the_setup; 369 370 // active connection - the one for which the_setup is used for 371 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 372 373 // @returns 1 if oob data is available 374 // stores oob data in provided 16 byte buffer if not null 375 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 376 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 377 378 // horizontal: initiator capabilities 379 // vertial: responder capabilities 380 static const stk_generation_method_t stk_generation_method [5] [5] = { 381 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 382 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 383 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 384 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 385 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 386 }; 387 388 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 389 #ifdef ENABLE_LE_SECURE_CONNECTIONS 390 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 391 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 392 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 393 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 394 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 395 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 396 }; 397 #endif 398 399 static void sm_run(void); 400 static void sm_done_for_handle(hci_con_handle_t con_handle); 401 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 402 static inline int sm_calc_actual_encryption_key_size(int other); 403 static int sm_validate_stk_generation_method(void); 404 static void sm_handle_encryption_result_address_resolution(void *arg); 405 static void sm_handle_encryption_result_dkg_dhk(void *arg); 406 static void sm_handle_encryption_result_dkg_irk(void *arg); 407 static void sm_handle_encryption_result_enc_a(void *arg); 408 static void sm_handle_encryption_result_enc_b(void *arg); 409 static void sm_handle_encryption_result_enc_c(void *arg); 410 static void sm_handle_encryption_result_enc_csrk(void *arg); 411 static void sm_handle_encryption_result_enc_d(void * arg); 412 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 413 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 414 #ifdef ENABLE_LE_PERIPHERAL 415 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 416 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 417 #endif 418 static void sm_handle_encryption_result_enc_stk(void *arg); 419 static void sm_handle_encryption_result_rau(void *arg); 420 static void sm_handle_random_result_ph2_tk(void * arg); 421 static void sm_handle_random_result_rau(void * arg); 422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 423 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 424 static void sm_ec_generate_new_key(void); 425 static void sm_handle_random_result_sc_get_random(void * arg); 426 static int sm_passkey_entry(stk_generation_method_t method); 427 #endif 428 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 429 430 static void log_info_hex16(const char * name, uint16_t value){ 431 log_info("%-6s 0x%04x", name, value); 432 } 433 434 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 435 // return packet[0]; 436 // } 437 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 438 return packet[1]; 439 } 440 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 441 return packet[2]; 442 } 443 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 444 return packet[3]; 445 } 446 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 447 return packet[4]; 448 } 449 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 450 return packet[5]; 451 } 452 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 453 return packet[6]; 454 } 455 456 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 457 packet[0] = code; 458 } 459 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 460 packet[1] = io_capability; 461 } 462 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 463 packet[2] = oob_data_flag; 464 } 465 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 466 packet[3] = auth_req; 467 } 468 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 469 packet[4] = max_encryption_key_size; 470 } 471 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 472 packet[5] = initiator_key_distribution; 473 } 474 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 475 packet[6] = responder_key_distribution; 476 } 477 478 // @returns 1 if all bytes are 0 479 static int sm_is_null(uint8_t * data, int size){ 480 int i; 481 for (i=0; i < size ; i++){ 482 if (data[i]) return 0; 483 } 484 return 1; 485 } 486 487 static int sm_is_null_random(uint8_t random[8]){ 488 return sm_is_null(random, 8); 489 } 490 491 static int sm_is_null_key(uint8_t * key){ 492 return sm_is_null(key, 16); 493 } 494 495 // Key utils 496 static void sm_reset_tk(void){ 497 int i; 498 for (i=0;i<16;i++){ 499 setup->sm_tk[i] = 0; 500 } 501 } 502 503 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 504 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 505 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 506 int i; 507 for (i = max_encryption_size ; i < 16 ; i++){ 508 key[15-i] = 0; 509 } 510 } 511 512 // ER / IR checks 513 static void sm_er_ir_set_default(void){ 514 int i; 515 for (i=0;i<16;i++){ 516 sm_persistent_er[i] = 0x30 + i; 517 sm_persistent_ir[i] = 0x90 + i; 518 } 519 } 520 521 static int sm_er_is_default(void){ 522 int i; 523 for (i=0;i<16;i++){ 524 if (sm_persistent_er[i] != (0x30+i)) return 0; 525 } 526 return 1; 527 } 528 529 static int sm_ir_is_default(void){ 530 int i; 531 for (i=0;i<16;i++){ 532 if (sm_persistent_ir[i] != (0x90+i)) return 0; 533 } 534 return 1; 535 } 536 537 // SMP Timeout implementation 538 539 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 540 // the Security Manager Timer shall be reset and started. 541 // 542 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 543 // 544 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 545 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 546 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 547 // established. 548 549 static void sm_timeout_handler(btstack_timer_source_t * timer){ 550 log_info("SM timeout"); 551 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 552 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 553 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 554 sm_done_for_handle(sm_conn->sm_handle); 555 556 // trigger handling of next ready connection 557 sm_run(); 558 } 559 static void sm_timeout_start(sm_connection_t * sm_conn){ 560 btstack_run_loop_remove_timer(&setup->sm_timeout); 561 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 562 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 563 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 564 btstack_run_loop_add_timer(&setup->sm_timeout); 565 } 566 static void sm_timeout_stop(void){ 567 btstack_run_loop_remove_timer(&setup->sm_timeout); 568 } 569 static void sm_timeout_reset(sm_connection_t * sm_conn){ 570 sm_timeout_stop(); 571 sm_timeout_start(sm_conn); 572 } 573 574 // end of sm timeout 575 576 // GAP Random Address updates 577 static gap_random_address_type_t gap_random_adress_type; 578 static btstack_timer_source_t gap_random_address_update_timer; 579 static uint32_t gap_random_adress_update_period; 580 581 static void gap_random_address_trigger(void){ 582 log_info("gap_random_address_trigger, state %u", rau_state); 583 if (rau_state != RAU_IDLE) return; 584 rau_state = RAU_GET_RANDOM; 585 sm_run(); 586 } 587 588 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 589 UNUSED(timer); 590 591 log_info("GAP Random Address Update due"); 592 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 593 btstack_run_loop_add_timer(&gap_random_address_update_timer); 594 gap_random_address_trigger(); 595 } 596 597 static void gap_random_address_update_start(void){ 598 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 599 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 600 btstack_run_loop_add_timer(&gap_random_address_update_timer); 601 } 602 603 static void gap_random_address_update_stop(void){ 604 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 605 } 606 607 // ah(k,r) helper 608 // r = padding || r 609 // r - 24 bit value 610 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 611 // r'= padding || r 612 memset(r_prime, 0, 16); 613 memcpy(&r_prime[13], r, 3); 614 } 615 616 // d1 helper 617 // d' = padding || r || d 618 // d,r - 16 bit values 619 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 620 // d'= padding || r || d 621 memset(d1_prime, 0, 16); 622 big_endian_store_16(d1_prime, 12, r); 623 big_endian_store_16(d1_prime, 14, d); 624 } 625 626 // dm helper 627 // r’ = padding || r 628 // r - 64 bit value 629 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 630 memset(r_prime, 0, 16); 631 memcpy(&r_prime[8], r, 8); 632 } 633 634 // calculate arguments for first AES128 operation in C1 function 635 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 636 637 // p1 = pres || preq || rat’ || iat’ 638 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 639 // cant octet of pres becomes the most significant octet of p1. 640 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 641 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 642 // p1 is 0x05000800000302070710000001010001." 643 644 sm_key_t p1; 645 reverse_56(pres, &p1[0]); 646 reverse_56(preq, &p1[7]); 647 p1[14] = rat; 648 p1[15] = iat; 649 log_info_key("p1", p1); 650 log_info_key("r", r); 651 652 // t1 = r xor p1 653 int i; 654 for (i=0;i<16;i++){ 655 t1[i] = r[i] ^ p1[i]; 656 } 657 log_info_key("t1", t1); 658 } 659 660 // calculate arguments for second AES128 operation in C1 function 661 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 662 // p2 = padding || ia || ra 663 // "The least significant octet of ra becomes the least significant octet of p2 and 664 // the most significant octet of padding becomes the most significant octet of p2. 665 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 666 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 667 668 sm_key_t p2; 669 memset(p2, 0, 16); 670 memcpy(&p2[4], ia, 6); 671 memcpy(&p2[10], ra, 6); 672 log_info_key("p2", p2); 673 674 // c1 = e(k, t2_xor_p2) 675 int i; 676 for (i=0;i<16;i++){ 677 t3[i] = t2[i] ^ p2[i]; 678 } 679 log_info_key("t3", t3); 680 } 681 682 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 683 log_info_key("r1", r1); 684 log_info_key("r2", r2); 685 memcpy(&r_prime[8], &r2[8], 8); 686 memcpy(&r_prime[0], &r1[8], 8); 687 } 688 689 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 690 UNUSED(channel); 691 692 // log event 693 hci_dump_packet(packet_type, 1, packet, size); 694 // dispatch to all event handlers 695 btstack_linked_list_iterator_t it; 696 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 697 while (btstack_linked_list_iterator_has_next(&it)){ 698 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 699 entry->callback(packet_type, 0, packet, size); 700 } 701 } 702 703 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 704 event[0] = type; 705 event[1] = event_size - 2; 706 little_endian_store_16(event, 2, con_handle); 707 event[4] = addr_type; 708 reverse_bd_addr(address, &event[5]); 709 } 710 711 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 712 uint8_t event[11]; 713 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 714 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 715 } 716 717 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 718 uint8_t event[15]; 719 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 720 little_endian_store_32(event, 11, passkey); 721 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 722 } 723 724 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 725 // fetch addr and addr type from db, only called for valid entries 726 bd_addr_t identity_address; 727 int identity_address_type; 728 le_device_db_info(index, &identity_address_type, identity_address, NULL); 729 730 uint8_t event[20]; 731 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 732 event[11] = identity_address_type; 733 reverse_bd_addr(identity_address, &event[12]); 734 little_endian_store_16(event, 18, index); 735 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 736 } 737 738 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 739 uint8_t event[12]; 740 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 741 event[11] = status; 742 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 743 } 744 745 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 746 uint8_t event[13]; 747 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 748 event[11] = status; 749 event[12] = reason; 750 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 751 } 752 753 // decide on stk generation based on 754 // - pairing request 755 // - io capabilities 756 // - OOB data availability 757 static void sm_setup_tk(void){ 758 759 // default: just works 760 setup->sm_stk_generation_method = JUST_WORKS; 761 762 #ifdef ENABLE_LE_SECURE_CONNECTIONS 763 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 764 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 765 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 766 #else 767 setup->sm_use_secure_connections = 0; 768 #endif 769 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 770 771 772 // decide if OOB will be used based on SC vs. Legacy and oob flags 773 int use_oob = 0; 774 if (setup->sm_use_secure_connections){ 775 // In LE Secure Connections pairing, the out of band method is used if at least 776 // one device has the peer device's out of band authentication data available. 777 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 778 } else { 779 // In LE legacy pairing, the out of band method is used if both the devices have 780 // the other device's out of band authentication data available. 781 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 782 } 783 if (use_oob){ 784 log_info("SM: have OOB data"); 785 log_info_key("OOB", setup->sm_tk); 786 setup->sm_stk_generation_method = OOB; 787 return; 788 } 789 790 // If both devices have not set the MITM option in the Authentication Requirements 791 // Flags, then the IO capabilities shall be ignored and the Just Works association 792 // model shall be used. 793 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 794 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 795 log_info("SM: MITM not required by both -> JUST WORKS"); 796 return; 797 } 798 799 // Reset TK as it has been setup in sm_init_setup 800 sm_reset_tk(); 801 802 // Also use just works if unknown io capabilites 803 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 804 return; 805 } 806 807 // Otherwise the IO capabilities of the devices shall be used to determine the 808 // pairing method as defined in Table 2.4. 809 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 810 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 811 812 #ifdef ENABLE_LE_SECURE_CONNECTIONS 813 // table not define by default 814 if (setup->sm_use_secure_connections){ 815 generation_method = stk_generation_method_with_secure_connection; 816 } 817 #endif 818 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 819 820 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 821 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 822 } 823 824 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 825 int flags = 0; 826 if (key_set & SM_KEYDIST_ENC_KEY){ 827 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 828 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 829 } 830 if (key_set & SM_KEYDIST_ID_KEY){ 831 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 832 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 833 } 834 if (key_set & SM_KEYDIST_SIGN){ 835 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 836 } 837 return flags; 838 } 839 840 static void sm_setup_key_distribution(uint8_t key_set){ 841 setup->sm_key_distribution_received_set = 0; 842 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 843 setup->sm_key_distribution_sent_set = 0; 844 setup->sm_le_device_index = -1; 845 } 846 847 // CSRK Key Lookup 848 849 850 static int sm_address_resolution_idle(void){ 851 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 852 } 853 854 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){ 855 memcpy(sm_address_resolution_address, addr, 6); 856 sm_address_resolution_addr_type = addr_type; 857 sm_address_resolution_test = 0; 858 sm_address_resolution_mode = mode; 859 sm_address_resolution_context = context; 860 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 861 } 862 863 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 864 // check if already in list 865 btstack_linked_list_iterator_t it; 866 sm_lookup_entry_t * entry; 867 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 868 while(btstack_linked_list_iterator_has_next(&it)){ 869 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 870 if (entry->address_type != address_type) continue; 871 if (memcmp(entry->address, address, 6)) continue; 872 // already in list 873 return BTSTACK_BUSY; 874 } 875 entry = btstack_memory_sm_lookup_entry_get(); 876 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 877 entry->address_type = (bd_addr_type_t) address_type; 878 memcpy(entry->address, address, 6); 879 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 880 sm_run(); 881 return 0; 882 } 883 884 // CMAC calculation using AES Engineq 885 #ifdef USE_CMAC_ENGINE 886 887 static void sm_cmac_done_trampoline(void * arg){ 888 UNUSED(arg); 889 sm_cmac_active = 0; 890 (*sm_cmac_done_callback)(sm_cmac_hash); 891 sm_run(); 892 } 893 894 int sm_cmac_ready(void){ 895 return sm_cmac_active == 0; 896 } 897 #endif 898 899 #ifdef ENABLE_LE_SECURE_CONNECTIONS 900 // generic cmac calculation 901 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)){ 902 sm_cmac_active = 1; 903 sm_cmac_done_callback = done_callback; 904 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 905 } 906 #endif 907 908 // cmac for ATT Message signing 909 #ifdef ENABLE_LE_SIGNED_WRITE 910 911 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)){ 912 sm_cmac_active = 1; 913 sm_cmac_done_callback = done_callback; 914 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 915 } 916 917 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 918 if (offset >= sm_cmac_signed_write_message_len) { 919 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 920 return 0; 921 } 922 923 offset = sm_cmac_signed_write_message_len - 1 - offset; 924 925 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 926 if (offset < 3){ 927 return sm_cmac_signed_write_header[offset]; 928 } 929 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 930 if (offset < actual_message_len_incl_header){ 931 return sm_cmac_signed_write_message[offset - 3]; 932 } 933 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 934 } 935 936 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)){ 937 // ATT Message Signing 938 sm_cmac_signed_write_header[0] = opcode; 939 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 940 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 941 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 942 sm_cmac_signed_write_message = message; 943 sm_cmac_signed_write_message_len = total_message_len; 944 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 945 } 946 #endif 947 948 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 949 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 950 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 951 switch (setup->sm_stk_generation_method){ 952 case PK_RESP_INPUT: 953 if (IS_RESPONDER(sm_conn->sm_role)){ 954 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 955 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 956 } else { 957 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)); 958 } 959 break; 960 case PK_INIT_INPUT: 961 if (IS_RESPONDER(sm_conn->sm_role)){ 962 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)); 963 } else { 964 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 965 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 966 } 967 break; 968 case PK_BOTH_INPUT: 969 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 970 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 971 break; 972 case NUMERIC_COMPARISON: 973 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 974 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)); 975 break; 976 case JUST_WORKS: 977 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 978 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 979 break; 980 case OOB: 981 // client already provided OOB data, let's skip notification. 982 break; 983 } 984 } 985 986 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 987 int recv_flags; 988 if (IS_RESPONDER(sm_conn->sm_role)){ 989 // slave / responder 990 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 991 } else { 992 // master / initiator 993 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 994 } 995 996 #ifdef ENABLE_LE_SECURE_CONNECTIONS 997 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 998 if (setup->sm_use_secure_connections){ 999 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1000 } 1001 #endif 1002 1003 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1004 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1005 } 1006 1007 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1008 if (sm_active_connection_handle == con_handle){ 1009 sm_timeout_stop(); 1010 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1011 log_info("sm: connection 0x%x released setup context", con_handle); 1012 1013 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1014 // generate new ec key after each pairing (that used it) 1015 if (setup->sm_use_secure_connections){ 1016 sm_ec_generate_new_key(); 1017 } 1018 #endif 1019 } 1020 } 1021 1022 static int sm_key_distribution_flags_for_auth_req(void){ 1023 1024 int flags = SM_KEYDIST_ID_KEY; 1025 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1026 // encryption and signing information only if bonding requested 1027 flags |= SM_KEYDIST_ENC_KEY; 1028 #ifdef ENABLE_LE_SIGNED_WRITE 1029 flags |= SM_KEYDIST_SIGN; 1030 #endif 1031 } 1032 return flags; 1033 } 1034 1035 static void sm_reset_setup(void){ 1036 // fill in sm setup 1037 setup->sm_state_vars = 0; 1038 setup->sm_keypress_notification = 0; 1039 sm_reset_tk(); 1040 } 1041 1042 static void sm_init_setup(sm_connection_t * sm_conn){ 1043 1044 // fill in sm setup 1045 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1046 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1047 1048 // query client for Legacy Pairing OOB data 1049 setup->sm_have_oob_data = 0; 1050 if (sm_get_oob_data) { 1051 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1052 } 1053 1054 // if available and SC supported, also ask for SC OOB Data 1055 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1056 memset(setup->sm_ra, 0, 16); 1057 memset(setup->sm_rb, 0, 16); 1058 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1059 if (sm_get_sc_oob_data){ 1060 if (IS_RESPONDER(sm_conn->sm_role)){ 1061 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1062 sm_conn->sm_peer_addr_type, 1063 sm_conn->sm_peer_address, 1064 setup->sm_peer_confirm, 1065 setup->sm_ra); 1066 } else { 1067 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1068 sm_conn->sm_peer_addr_type, 1069 sm_conn->sm_peer_address, 1070 setup->sm_peer_confirm, 1071 setup->sm_rb); 1072 } 1073 } else { 1074 setup->sm_have_oob_data = 0; 1075 } 1076 } 1077 #endif 1078 1079 sm_pairing_packet_t * local_packet; 1080 if (IS_RESPONDER(sm_conn->sm_role)){ 1081 // slave 1082 local_packet = &setup->sm_s_pres; 1083 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1084 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1085 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1086 } else { 1087 // master 1088 local_packet = &setup->sm_m_preq; 1089 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1090 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1091 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1092 1093 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1094 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1095 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1096 } 1097 1098 uint8_t auth_req = sm_auth_req; 1099 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1100 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1101 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1102 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1103 } 1104 1105 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1106 1107 sm_pairing_packet_t * remote_packet; 1108 int remote_key_request; 1109 if (IS_RESPONDER(sm_conn->sm_role)){ 1110 // slave / responder 1111 remote_packet = &setup->sm_m_preq; 1112 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1113 } else { 1114 // master / initiator 1115 remote_packet = &setup->sm_s_pres; 1116 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1117 } 1118 1119 // check key size 1120 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1121 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1122 1123 // decide on STK generation method / SC 1124 sm_setup_tk(); 1125 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1126 1127 // check if STK generation method is acceptable by client 1128 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1129 1130 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1131 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1132 if (setup->sm_use_secure_connections){ 1133 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1134 } 1135 #endif 1136 1137 // identical to responder 1138 sm_setup_key_distribution(remote_key_request); 1139 1140 // JUST WORKS doens't provide authentication 1141 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1142 1143 return 0; 1144 } 1145 1146 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1147 1148 // cache and reset context 1149 int matched_device_id = sm_address_resolution_test; 1150 address_resolution_mode_t mode = sm_address_resolution_mode; 1151 void * context = sm_address_resolution_context; 1152 1153 // reset context 1154 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1155 sm_address_resolution_context = NULL; 1156 sm_address_resolution_test = -1; 1157 hci_con_handle_t con_handle = 0; 1158 1159 sm_connection_t * sm_connection; 1160 #ifdef ENABLE_LE_CENTRAL 1161 sm_key_t ltk; 1162 int have_ltk; 1163 int pairing_need; 1164 #endif 1165 switch (mode){ 1166 case ADDRESS_RESOLUTION_GENERAL: 1167 break; 1168 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1169 sm_connection = (sm_connection_t *) context; 1170 con_handle = sm_connection->sm_handle; 1171 switch (event){ 1172 case ADDRESS_RESOLUTION_SUCEEDED: 1173 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1174 sm_connection->sm_le_db_index = matched_device_id; 1175 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1176 if (sm_connection->sm_role) { 1177 // LTK request received before, IRK required -> start LTK calculation 1178 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1179 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1180 } 1181 break; 1182 } 1183 #ifdef ENABLE_LE_CENTRAL 1184 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1185 have_ltk = !sm_is_null_key(ltk); 1186 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1187 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1188 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1189 // reset requests 1190 sm_connection->sm_security_request_received = 0; 1191 sm_connection->sm_pairing_requested = 0; 1192 1193 // have ltk -> start encryption 1194 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1195 // "When a bond has been created between two devices, any reconnection should result in the local device 1196 // enabling or requesting encryption with the remote device before initiating any service request." 1197 if (have_ltk){ 1198 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1199 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1200 break; 1201 #else 1202 log_info("central: defer enabling encryption for bonded device"); 1203 #endif 1204 } 1205 // pairint_request -> send pairing request 1206 if (pairing_need){ 1207 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1208 break; 1209 } 1210 #endif 1211 break; 1212 case ADDRESS_RESOLUTION_FAILED: 1213 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1214 if (sm_connection->sm_role) { 1215 // LTK request received before, IRK required -> negative LTK reply 1216 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1217 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1218 } 1219 break; 1220 } 1221 #ifdef ENABLE_LE_CENTRAL 1222 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1223 sm_connection->sm_security_request_received = 0; 1224 sm_connection->sm_pairing_requested = 0; 1225 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1226 #endif 1227 break; 1228 } 1229 break; 1230 default: 1231 break; 1232 } 1233 1234 switch (event){ 1235 case ADDRESS_RESOLUTION_SUCEEDED: 1236 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1237 break; 1238 case ADDRESS_RESOLUTION_FAILED: 1239 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1240 break; 1241 } 1242 } 1243 1244 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1245 1246 int le_db_index = -1; 1247 1248 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1249 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1250 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1251 & SM_AUTHREQ_BONDING ) != 0; 1252 1253 if (bonding_enabed){ 1254 1255 // lookup device based on IRK 1256 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1257 int i; 1258 for (i=0; i < le_device_db_max_count(); i++){ 1259 sm_key_t irk; 1260 bd_addr_t address; 1261 int address_type = BD_ADDR_TYPE_UNKNOWN; 1262 le_device_db_info(i, &address_type, address, irk); 1263 // skip unused entries 1264 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1265 // compare IRK 1266 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1267 1268 log_info("sm: device found for IRK, updating"); 1269 le_db_index = i; 1270 break; 1271 } 1272 } else { 1273 // assert IRK is set to zero 1274 memset(setup->sm_peer_irk, 0, 16); 1275 } 1276 1277 // if not found, lookup via public address if possible 1278 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1279 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1280 int i; 1281 for (i=0; i < le_device_db_max_count(); i++){ 1282 bd_addr_t address; 1283 int address_type = BD_ADDR_TYPE_UNKNOWN; 1284 le_device_db_info(i, &address_type, address, NULL); 1285 // skip unused entries 1286 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1287 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1288 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1289 log_info("sm: device found for public address, updating"); 1290 le_db_index = i; 1291 break; 1292 } 1293 } 1294 } 1295 1296 // if not found, add to db 1297 if (le_db_index < 0) { 1298 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1299 } 1300 1301 if (le_db_index >= 0){ 1302 1303 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1304 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1305 1306 #ifdef ENABLE_LE_SIGNED_WRITE 1307 // store local CSRK 1308 setup->sm_le_device_index = le_db_index; 1309 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1310 log_info("sm: store local CSRK"); 1311 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1312 le_device_db_local_counter_set(le_db_index, 0); 1313 } 1314 1315 // store remote CSRK 1316 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1317 log_info("sm: store remote CSRK"); 1318 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1319 le_device_db_remote_counter_set(le_db_index, 0); 1320 } 1321 #endif 1322 // store encryption information for secure connections: LTK generated by ECDH 1323 if (setup->sm_use_secure_connections){ 1324 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1325 uint8_t zero_rand[8]; 1326 memset(zero_rand, 0, 8); 1327 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1328 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1329 } 1330 1331 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1332 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1333 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1334 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1335 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1336 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1337 1338 } 1339 } 1340 } else { 1341 log_info("Ignoring received keys, bonding not enabled"); 1342 } 1343 1344 // keep le_db_index 1345 sm_conn->sm_le_db_index = le_db_index; 1346 } 1347 1348 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1349 setup->sm_pairing_failed_reason = reason; 1350 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1351 } 1352 1353 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1354 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1355 } 1356 1357 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1358 1359 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1360 static int sm_passkey_used(stk_generation_method_t method); 1361 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1362 1363 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1364 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1365 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1366 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1367 } else { 1368 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1369 } 1370 } 1371 1372 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1373 if (IS_RESPONDER(sm_conn->sm_role)){ 1374 // Responder 1375 if (setup->sm_stk_generation_method == OOB){ 1376 // generate Nb 1377 log_info("Generate Nb"); 1378 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1379 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 1380 } else { 1381 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1382 } 1383 } else { 1384 // Initiator role 1385 switch (setup->sm_stk_generation_method){ 1386 case JUST_WORKS: 1387 sm_sc_prepare_dhkey_check(sm_conn); 1388 break; 1389 1390 case NUMERIC_COMPARISON: 1391 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1392 break; 1393 case PK_INIT_INPUT: 1394 case PK_RESP_INPUT: 1395 case PK_BOTH_INPUT: 1396 if (setup->sm_passkey_bit < 20) { 1397 sm_sc_start_calculating_local_confirm(sm_conn); 1398 } else { 1399 sm_sc_prepare_dhkey_check(sm_conn); 1400 } 1401 break; 1402 case OOB: 1403 sm_sc_prepare_dhkey_check(sm_conn); 1404 break; 1405 } 1406 } 1407 } 1408 1409 static void sm_sc_cmac_done(uint8_t * hash){ 1410 log_info("sm_sc_cmac_done: "); 1411 log_info_hexdump(hash, 16); 1412 1413 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1414 sm_sc_oob_state = SM_SC_OOB_IDLE; 1415 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1416 return; 1417 } 1418 1419 sm_connection_t * sm_conn = sm_cmac_connection; 1420 sm_cmac_connection = NULL; 1421 #ifdef ENABLE_CLASSIC 1422 link_key_type_t link_key_type; 1423 #endif 1424 1425 switch (sm_conn->sm_engine_state){ 1426 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1427 memcpy(setup->sm_local_confirm, hash, 16); 1428 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1429 break; 1430 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1431 // check 1432 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1433 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1434 break; 1435 } 1436 sm_sc_state_after_receiving_random(sm_conn); 1437 break; 1438 case SM_SC_W4_CALCULATE_G2: { 1439 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1440 big_endian_store_32(setup->sm_tk, 12, vab); 1441 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1442 sm_trigger_user_response(sm_conn); 1443 break; 1444 } 1445 case SM_SC_W4_CALCULATE_F5_SALT: 1446 memcpy(setup->sm_t, hash, 16); 1447 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1448 break; 1449 case SM_SC_W4_CALCULATE_F5_MACKEY: 1450 memcpy(setup->sm_mackey, hash, 16); 1451 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1452 break; 1453 case SM_SC_W4_CALCULATE_F5_LTK: 1454 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1455 // Errata Service Release to the Bluetooth Specification: ESR09 1456 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1457 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1458 memcpy(setup->sm_ltk, hash, 16); 1459 memcpy(setup->sm_local_ltk, hash, 16); 1460 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1461 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1462 break; 1463 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1464 memcpy(setup->sm_local_dhkey_check, hash, 16); 1465 if (IS_RESPONDER(sm_conn->sm_role)){ 1466 // responder 1467 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1468 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1469 } else { 1470 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1471 } 1472 } else { 1473 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1474 } 1475 break; 1476 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1477 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1478 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1479 break; 1480 } 1481 if (IS_RESPONDER(sm_conn->sm_role)){ 1482 // responder 1483 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1484 } else { 1485 // initiator 1486 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1487 } 1488 break; 1489 case SM_SC_W4_CALCULATE_H6_ILK: 1490 memcpy(setup->sm_t, hash, 16); 1491 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1492 break; 1493 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1494 #ifdef ENABLE_CLASSIC 1495 reverse_128(hash, setup->sm_t); 1496 link_key_type = sm_conn->sm_connection_authenticated ? 1497 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1498 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1499 if (IS_RESPONDER(sm_conn->sm_role)){ 1500 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1501 } else { 1502 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1503 } 1504 #endif 1505 if (IS_RESPONDER(sm_conn->sm_role)){ 1506 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1507 } else { 1508 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1509 } 1510 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1511 sm_done_for_handle(sm_conn->sm_handle); 1512 break; 1513 default: 1514 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1515 break; 1516 } 1517 sm_run(); 1518 } 1519 1520 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1521 const uint16_t message_len = 65; 1522 sm_cmac_connection = sm_conn; 1523 memcpy(sm_cmac_sc_buffer, u, 32); 1524 memcpy(sm_cmac_sc_buffer+32, v, 32); 1525 sm_cmac_sc_buffer[64] = z; 1526 log_info("f4 key"); 1527 log_info_hexdump(x, 16); 1528 log_info("f4 message"); 1529 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1530 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1531 } 1532 1533 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1534 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1535 static const uint8_t f5_length[] = { 0x01, 0x00}; 1536 1537 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1538 log_info("f5_calculate_salt"); 1539 // calculate salt for f5 1540 const uint16_t message_len = 32; 1541 sm_cmac_connection = sm_conn; 1542 memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1543 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1544 } 1545 1546 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1547 const uint16_t message_len = 53; 1548 sm_cmac_connection = sm_conn; 1549 1550 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1551 sm_cmac_sc_buffer[0] = 0; 1552 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1553 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1554 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1555 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1556 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1557 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1558 log_info("f5 key"); 1559 log_info_hexdump(t, 16); 1560 log_info("f5 message for MacKey"); 1561 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1562 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1563 } 1564 1565 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1566 sm_key56_t bd_addr_master, bd_addr_slave; 1567 bd_addr_master[0] = setup->sm_m_addr_type; 1568 bd_addr_slave[0] = setup->sm_s_addr_type; 1569 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1570 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1571 if (IS_RESPONDER(sm_conn->sm_role)){ 1572 // responder 1573 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1574 } else { 1575 // initiator 1576 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1577 } 1578 } 1579 1580 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1581 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1582 const uint16_t message_len = 53; 1583 sm_cmac_connection = sm_conn; 1584 sm_cmac_sc_buffer[0] = 1; 1585 // 1..52 setup before 1586 log_info("f5 key"); 1587 log_info_hexdump(t, 16); 1588 log_info("f5 message for LTK"); 1589 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1590 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1591 } 1592 1593 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1594 f5_ltk(sm_conn, setup->sm_t); 1595 } 1596 1597 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1598 const uint16_t message_len = 65; 1599 sm_cmac_connection = sm_conn; 1600 memcpy(sm_cmac_sc_buffer, n1, 16); 1601 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1602 memcpy(sm_cmac_sc_buffer+32, r, 16); 1603 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1604 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1605 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1606 log_info("f6 key"); 1607 log_info_hexdump(w, 16); 1608 log_info("f6 message"); 1609 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1610 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1611 } 1612 1613 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1614 // - U is 256 bits 1615 // - V is 256 bits 1616 // - X is 128 bits 1617 // - Y is 128 bits 1618 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1619 const uint16_t message_len = 80; 1620 sm_cmac_connection = sm_conn; 1621 memcpy(sm_cmac_sc_buffer, u, 32); 1622 memcpy(sm_cmac_sc_buffer+32, v, 32); 1623 memcpy(sm_cmac_sc_buffer+64, y, 16); 1624 log_info("g2 key"); 1625 log_info_hexdump(x, 16); 1626 log_info("g2 message"); 1627 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1628 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1629 } 1630 1631 static void g2_calculate(sm_connection_t * sm_conn) { 1632 // calc Va if numeric comparison 1633 if (IS_RESPONDER(sm_conn->sm_role)){ 1634 // responder 1635 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1636 } else { 1637 // initiator 1638 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1639 } 1640 } 1641 1642 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1643 uint8_t z = 0; 1644 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1645 // some form of passkey 1646 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1647 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1648 setup->sm_passkey_bit++; 1649 } 1650 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1651 } 1652 1653 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1654 // OOB 1655 if (setup->sm_stk_generation_method == OOB){ 1656 if (IS_RESPONDER(sm_conn->sm_role)){ 1657 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1658 } else { 1659 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1660 } 1661 return; 1662 } 1663 1664 uint8_t z = 0; 1665 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1666 // some form of passkey 1667 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1668 // sm_passkey_bit was increased before sending confirm value 1669 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1670 } 1671 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1672 } 1673 1674 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1675 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED ? 1 : 0); 1676 1677 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1678 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1679 return; 1680 } else { 1681 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1682 } 1683 } 1684 1685 static void sm_sc_dhkey_calculated(void * arg){ 1686 sm_connection_t * sm_conn = (sm_connection_t *) arg; 1687 log_info("dhkey"); 1688 log_info_hexdump(&setup->sm_dhkey[0], 32); 1689 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1690 // trigger next step 1691 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1692 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1693 } 1694 sm_run(); 1695 } 1696 1697 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1698 // calculate DHKCheck 1699 sm_key56_t bd_addr_master, bd_addr_slave; 1700 bd_addr_master[0] = setup->sm_m_addr_type; 1701 bd_addr_slave[0] = setup->sm_s_addr_type; 1702 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1703 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1704 uint8_t iocap_a[3]; 1705 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1706 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1707 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1708 uint8_t iocap_b[3]; 1709 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1710 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1711 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1712 if (IS_RESPONDER(sm_conn->sm_role)){ 1713 // responder 1714 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); 1715 } else { 1716 // initiator 1717 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); 1718 } 1719 } 1720 1721 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1722 // validate E = f6() 1723 sm_key56_t bd_addr_master, bd_addr_slave; 1724 bd_addr_master[0] = setup->sm_m_addr_type; 1725 bd_addr_slave[0] = setup->sm_s_addr_type; 1726 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1727 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1728 1729 uint8_t iocap_a[3]; 1730 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1731 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1732 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1733 uint8_t iocap_b[3]; 1734 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1735 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1736 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1737 if (IS_RESPONDER(sm_conn->sm_role)){ 1738 // responder 1739 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); 1740 } else { 1741 // initiator 1742 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); 1743 } 1744 } 1745 1746 1747 // 1748 // Link Key Conversion Function h6 1749 // 1750 // h6(W, keyID) = AES-CMACW(keyID) 1751 // - W is 128 bits 1752 // - keyID is 32 bits 1753 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1754 const uint16_t message_len = 4; 1755 sm_cmac_connection = sm_conn; 1756 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1757 log_info("h6 key"); 1758 log_info_hexdump(w, 16); 1759 log_info("h6 message"); 1760 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1761 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1762 } 1763 1764 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1765 // Errata Service Release to the Bluetooth Specification: ESR09 1766 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1767 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1768 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1769 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1770 } 1771 1772 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1773 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1774 } 1775 1776 #endif 1777 1778 // key management legacy connections: 1779 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1780 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1781 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1782 // - responder reconnects: responder uses LTK receveived from master 1783 1784 // key management secure connections: 1785 // - both devices store same LTK from ECDH key exchange. 1786 1787 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1788 static void sm_load_security_info(sm_connection_t * sm_connection){ 1789 int encryption_key_size; 1790 int authenticated; 1791 int authorized; 1792 int secure_connection; 1793 1794 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1795 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1796 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1797 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); 1798 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1799 sm_connection->sm_connection_authenticated = authenticated; 1800 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1801 sm_connection->sm_connection_sc = secure_connection; 1802 } 1803 #endif 1804 1805 #ifdef ENABLE_LE_PERIPHERAL 1806 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1807 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1808 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1809 // re-establish used key encryption size 1810 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1811 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1812 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1813 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1814 // Legacy paring -> not SC 1815 sm_connection->sm_connection_sc = 0; 1816 log_info("sm: received ltk request with key size %u, authenticated %u", 1817 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1818 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1819 sm_run(); 1820 } 1821 #endif 1822 1823 static void sm_run(void){ 1824 1825 btstack_linked_list_iterator_t it; 1826 1827 // assert that stack has already bootet 1828 if (hci_get_state() != HCI_STATE_WORKING) return; 1829 1830 // assert that we can send at least commands 1831 if (!hci_can_send_command_packet_now()) return; 1832 1833 // pause until IR/ER are ready 1834 if (sm_persistent_keys_random_active) return; 1835 1836 // 1837 // non-connection related behaviour 1838 // 1839 1840 // distributed key generation 1841 switch (dkg_state){ 1842 case DKG_CALC_IRK: 1843 // already busy? 1844 if (sm_aes128_state == SM_AES128_IDLE) { 1845 log_info("DKG_CALC_IRK started"); 1846 // IRK = d1(IR, 1, 0) 1847 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1848 sm_aes128_state = SM_AES128_ACTIVE; 1849 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1850 return; 1851 } 1852 break; 1853 case DKG_CALC_DHK: 1854 // already busy? 1855 if (sm_aes128_state == SM_AES128_IDLE) { 1856 log_info("DKG_CALC_DHK started"); 1857 // DHK = d1(IR, 3, 0) 1858 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1859 sm_aes128_state = SM_AES128_ACTIVE; 1860 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1861 return; 1862 } 1863 break; 1864 default: 1865 break; 1866 } 1867 1868 // random address updates 1869 switch (rau_state){ 1870 case RAU_GET_RANDOM: 1871 rau_state = RAU_W4_RANDOM; 1872 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1873 return; 1874 case RAU_GET_ENC: 1875 // already busy? 1876 if (sm_aes128_state == SM_AES128_IDLE) { 1877 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1878 sm_aes128_state = SM_AES128_ACTIVE; 1879 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1880 return; 1881 } 1882 break; 1883 case RAU_SET_ADDRESS: 1884 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1885 rau_state = RAU_IDLE; 1886 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1887 return; 1888 default: 1889 break; 1890 } 1891 1892 // CSRK Lookup 1893 // -- if csrk lookup ready, find connection that require csrk lookup 1894 if (sm_address_resolution_idle()){ 1895 hci_connections_get_iterator(&it); 1896 while(btstack_linked_list_iterator_has_next(&it)){ 1897 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1898 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1899 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1900 // and start lookup 1901 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); 1902 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1903 break; 1904 } 1905 } 1906 } 1907 1908 // -- if csrk lookup ready, resolved addresses for received addresses 1909 if (sm_address_resolution_idle()) { 1910 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1911 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1912 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1913 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1914 btstack_memory_sm_lookup_entry_free(entry); 1915 } 1916 } 1917 1918 // -- Continue with CSRK device lookup by public or resolvable private address 1919 if (!sm_address_resolution_idle()){ 1920 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1921 while (sm_address_resolution_test < le_device_db_max_count()){ 1922 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1923 bd_addr_t addr; 1924 sm_key_t irk; 1925 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1926 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1927 1928 // skip unused entries 1929 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1930 sm_address_resolution_test++; 1931 continue; 1932 } 1933 1934 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1935 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1936 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1937 break; 1938 } 1939 1940 // if connection type is public, it must be a different one 1941 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1942 sm_address_resolution_test++; 1943 continue; 1944 } 1945 1946 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1947 1948 log_info("LE Device Lookup: calculate AH"); 1949 log_info_key("IRK", irk); 1950 1951 memcpy(sm_aes128_key, irk, 16); 1952 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1953 sm_address_resolution_ah_calculation_active = 1; 1954 sm_aes128_state = SM_AES128_ACTIVE; 1955 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1956 return; 1957 } 1958 1959 if (sm_address_resolution_test >= le_device_db_max_count()){ 1960 log_info("LE Device Lookup: not found"); 1961 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1962 } 1963 } 1964 1965 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1966 switch (sm_sc_oob_state){ 1967 case SM_SC_OOB_W2_CALC_CONFIRM: 1968 if (!sm_cmac_ready()) break; 1969 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1970 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1971 return; 1972 default: 1973 break; 1974 } 1975 #endif 1976 1977 // assert that we can send at least commands - cmd might have been sent by crypto engine 1978 if (!hci_can_send_command_packet_now()) return; 1979 1980 // handle basic actions that don't requires the full context 1981 hci_connections_get_iterator(&it); 1982 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1983 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1984 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1985 switch(sm_connection->sm_engine_state){ 1986 // responder side 1987 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1988 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1989 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1990 return; 1991 1992 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1993 case SM_SC_RECEIVED_LTK_REQUEST: 1994 switch (sm_connection->sm_irk_lookup_state){ 1995 case IRK_LOOKUP_FAILED: 1996 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1997 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1998 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1999 return; 2000 default: 2001 break; 2002 } 2003 break; 2004 #endif 2005 default: 2006 break; 2007 } 2008 } 2009 2010 // 2011 // active connection handling 2012 // -- use loop to handle next connection if lock on setup context is released 2013 2014 while (1) { 2015 2016 // Find connections that requires setup context and make active if no other is locked 2017 hci_connections_get_iterator(&it); 2018 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2019 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2020 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2021 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2022 int done = 1; 2023 int err; 2024 UNUSED(err); 2025 2026 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2027 // assert ec key is ready 2028 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2029 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2030 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2031 sm_ec_generate_new_key(); 2032 } 2033 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2034 continue; 2035 } 2036 } 2037 #endif 2038 2039 switch (sm_connection->sm_engine_state) { 2040 #ifdef ENABLE_LE_PERIPHERAL 2041 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2042 // send packet if possible, 2043 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2044 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2045 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2046 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2047 } else { 2048 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2049 } 2050 // don't lock sxetup context yet 2051 done = 0; 2052 break; 2053 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2054 sm_reset_setup(); 2055 sm_init_setup(sm_connection); 2056 // recover pairing request 2057 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2058 err = sm_stk_generation_init(sm_connection); 2059 2060 #ifdef ENABLE_TESTING_SUPPORT 2061 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2062 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2063 err = test_pairing_failure; 2064 } 2065 #endif 2066 if (err){ 2067 setup->sm_pairing_failed_reason = err; 2068 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2069 break; 2070 } 2071 sm_timeout_start(sm_connection); 2072 // generate random number first, if we need to show passkey 2073 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2074 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_connection); 2075 break; 2076 } 2077 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2078 break; 2079 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2080 sm_reset_setup(); 2081 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2082 break; 2083 2084 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2085 case SM_SC_RECEIVED_LTK_REQUEST: 2086 switch (sm_connection->sm_irk_lookup_state){ 2087 case IRK_LOOKUP_SUCCEEDED: 2088 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2089 // start using context by loading security info 2090 sm_reset_setup(); 2091 sm_load_security_info(sm_connection); 2092 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2093 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2094 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2095 break; 2096 } 2097 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2098 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2099 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2100 // don't lock setup context yet 2101 return; 2102 default: 2103 // just wait until IRK lookup is completed 2104 // don't lock setup context yet 2105 done = 0; 2106 break; 2107 } 2108 break; 2109 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2110 #endif /* ENABLE_LE_PERIPHERAL */ 2111 2112 #ifdef ENABLE_LE_CENTRAL 2113 case SM_INITIATOR_PH0_HAS_LTK: 2114 sm_reset_setup(); 2115 sm_load_security_info(sm_connection); 2116 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2117 break; 2118 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2119 sm_reset_setup(); 2120 sm_init_setup(sm_connection); 2121 sm_timeout_start(sm_connection); 2122 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2123 break; 2124 #endif 2125 2126 default: 2127 done = 0; 2128 break; 2129 } 2130 if (done){ 2131 sm_active_connection_handle = sm_connection->sm_handle; 2132 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); 2133 } 2134 } 2135 2136 // 2137 // active connection handling 2138 // 2139 2140 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2141 2142 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2143 if (!connection) { 2144 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2145 return; 2146 } 2147 2148 // assert that we could send a SM PDU - not needed for all of the following 2149 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2150 log_info("cannot send now, requesting can send now event"); 2151 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2152 return; 2153 } 2154 2155 // send keypress notifications 2156 if (setup->sm_keypress_notification){ 2157 int i; 2158 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2159 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2160 uint8_t action = 0; 2161 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2162 if (flags & (1<<i)){ 2163 int clear_flag = 1; 2164 switch (i){ 2165 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2166 case SM_KEYPRESS_PASSKEY_CLEARED: 2167 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2168 default: 2169 break; 2170 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2171 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2172 num_actions--; 2173 clear_flag = num_actions == 0; 2174 break; 2175 } 2176 if (clear_flag){ 2177 flags &= ~(1<<i); 2178 } 2179 action = i; 2180 break; 2181 } 2182 } 2183 setup->sm_keypress_notification = (num_actions << 5) | flags; 2184 2185 // send keypress notification 2186 uint8_t buffer[2]; 2187 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2188 buffer[1] = action; 2189 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2190 2191 // try 2192 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2193 return; 2194 } 2195 2196 int key_distribution_flags; 2197 UNUSED(key_distribution_flags); 2198 2199 log_info("sm_run: state %u", connection->sm_engine_state); 2200 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2201 log_info("sm_run // cannot send"); 2202 } 2203 switch (connection->sm_engine_state){ 2204 2205 // general 2206 case SM_GENERAL_SEND_PAIRING_FAILED: { 2207 uint8_t buffer[2]; 2208 buffer[0] = SM_CODE_PAIRING_FAILED; 2209 buffer[1] = setup->sm_pairing_failed_reason; 2210 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2211 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2212 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2213 sm_done_for_handle(connection->sm_handle); 2214 break; 2215 } 2216 2217 // responding state 2218 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2219 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2220 if (!sm_cmac_ready()) break; 2221 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2222 sm_sc_calculate_local_confirm(connection); 2223 break; 2224 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2225 if (!sm_cmac_ready()) break; 2226 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2227 sm_sc_calculate_remote_confirm(connection); 2228 break; 2229 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2230 if (!sm_cmac_ready()) break; 2231 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2232 sm_sc_calculate_f6_for_dhkey_check(connection); 2233 break; 2234 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2235 if (!sm_cmac_ready()) break; 2236 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2237 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2238 break; 2239 case SM_SC_W2_CALCULATE_F5_SALT: 2240 if (!sm_cmac_ready()) break; 2241 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2242 f5_calculate_salt(connection); 2243 break; 2244 case SM_SC_W2_CALCULATE_F5_MACKEY: 2245 if (!sm_cmac_ready()) break; 2246 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2247 f5_calculate_mackey(connection); 2248 break; 2249 case SM_SC_W2_CALCULATE_F5_LTK: 2250 if (!sm_cmac_ready()) break; 2251 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2252 f5_calculate_ltk(connection); 2253 break; 2254 case SM_SC_W2_CALCULATE_G2: 2255 if (!sm_cmac_ready()) break; 2256 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2257 g2_calculate(connection); 2258 break; 2259 case SM_SC_W2_CALCULATE_H6_ILK: 2260 if (!sm_cmac_ready()) break; 2261 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2262 h6_calculate_ilk(connection); 2263 break; 2264 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2265 if (!sm_cmac_ready()) break; 2266 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2267 h6_calculate_br_edr_link_key(connection); 2268 break; 2269 #endif 2270 2271 #ifdef ENABLE_LE_CENTRAL 2272 // initiator side 2273 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2274 sm_key_t peer_ltk_flipped; 2275 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2276 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2277 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2278 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2279 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2280 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2281 return; 2282 } 2283 2284 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2285 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2286 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2287 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2288 sm_timeout_reset(connection); 2289 break; 2290 #endif 2291 2292 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2293 2294 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2295 int trigger_user_response = 0; 2296 2297 uint8_t buffer[65]; 2298 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2299 // 2300 reverse_256(&ec_q[0], &buffer[1]); 2301 reverse_256(&ec_q[32], &buffer[33]); 2302 2303 #ifdef ENABLE_TESTING_SUPPORT 2304 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2305 log_info("testing_support: invalidating public key"); 2306 // flip single bit of public key coordinate 2307 buffer[1] ^= 1; 2308 } 2309 #endif 2310 2311 // stk generation method 2312 // passkey entry: notify app to show passkey or to request passkey 2313 switch (setup->sm_stk_generation_method){ 2314 case JUST_WORKS: 2315 case NUMERIC_COMPARISON: 2316 if (IS_RESPONDER(connection->sm_role)){ 2317 // responder 2318 sm_sc_start_calculating_local_confirm(connection); 2319 } else { 2320 // initiator 2321 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2322 } 2323 break; 2324 case PK_INIT_INPUT: 2325 case PK_RESP_INPUT: 2326 case PK_BOTH_INPUT: 2327 // use random TK for display 2328 memcpy(setup->sm_ra, setup->sm_tk, 16); 2329 memcpy(setup->sm_rb, setup->sm_tk, 16); 2330 setup->sm_passkey_bit = 0; 2331 2332 if (IS_RESPONDER(connection->sm_role)){ 2333 // responder 2334 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2335 } else { 2336 // initiator 2337 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2338 } 2339 trigger_user_response = 1; 2340 break; 2341 case OOB: 2342 if (IS_RESPONDER(connection->sm_role)){ 2343 // responder 2344 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2345 } else { 2346 // initiator 2347 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2348 } 2349 break; 2350 } 2351 2352 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2353 sm_timeout_reset(connection); 2354 2355 // trigger user response after sending pdu 2356 if (trigger_user_response){ 2357 sm_trigger_user_response(connection); 2358 } 2359 break; 2360 } 2361 case SM_SC_SEND_CONFIRMATION: { 2362 uint8_t buffer[17]; 2363 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2364 reverse_128(setup->sm_local_confirm, &buffer[1]); 2365 if (IS_RESPONDER(connection->sm_role)){ 2366 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2367 } else { 2368 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2369 } 2370 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2371 sm_timeout_reset(connection); 2372 break; 2373 } 2374 case SM_SC_SEND_PAIRING_RANDOM: { 2375 uint8_t buffer[17]; 2376 buffer[0] = SM_CODE_PAIRING_RANDOM; 2377 reverse_128(setup->sm_local_nonce, &buffer[1]); 2378 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2379 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2380 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2381 if (IS_RESPONDER(connection->sm_role)){ 2382 // responder 2383 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2384 } else { 2385 // initiator 2386 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2387 } 2388 } else { 2389 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2390 if (IS_RESPONDER(connection->sm_role)){ 2391 // responder 2392 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2393 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2394 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2395 } else { 2396 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2397 sm_sc_prepare_dhkey_check(connection); 2398 } 2399 } else { 2400 // initiator 2401 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2402 } 2403 } 2404 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2405 sm_timeout_reset(connection); 2406 break; 2407 } 2408 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2409 uint8_t buffer[17]; 2410 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2411 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2412 2413 if (IS_RESPONDER(connection->sm_role)){ 2414 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2415 } else { 2416 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2417 } 2418 2419 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2420 sm_timeout_reset(connection); 2421 break; 2422 } 2423 2424 #endif 2425 2426 #ifdef ENABLE_LE_PERIPHERAL 2427 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2428 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2429 2430 // start with initiator key dist flags 2431 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2432 2433 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2434 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2435 if (setup->sm_use_secure_connections){ 2436 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2437 } 2438 #endif 2439 // setup in response 2440 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); 2441 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); 2442 2443 // update key distribution after ENC was dropped 2444 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2445 2446 if (setup->sm_use_secure_connections){ 2447 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2448 } else { 2449 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2450 } 2451 2452 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2453 sm_timeout_reset(connection); 2454 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2455 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2456 sm_trigger_user_response(connection); 2457 } 2458 return; 2459 #endif 2460 2461 case SM_PH2_SEND_PAIRING_RANDOM: { 2462 uint8_t buffer[17]; 2463 buffer[0] = SM_CODE_PAIRING_RANDOM; 2464 reverse_128(setup->sm_local_random, &buffer[1]); 2465 if (IS_RESPONDER(connection->sm_role)){ 2466 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2467 } else { 2468 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2469 } 2470 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2471 sm_timeout_reset(connection); 2472 break; 2473 } 2474 2475 case SM_PH2_C1_GET_ENC_A: 2476 // already busy? 2477 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2478 // calculate confirm using aes128 engine - step 1 2479 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); 2480 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2481 sm_aes128_state = SM_AES128_ACTIVE; 2482 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, connection); 2483 break; 2484 2485 case SM_PH2_C1_GET_ENC_C: 2486 // already busy? 2487 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2488 // calculate m_confirm using aes128 engine - step 1 2489 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); 2490 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2491 sm_aes128_state = SM_AES128_ACTIVE; 2492 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, connection); 2493 break; 2494 2495 case SM_PH2_CALC_STK: 2496 // already busy? 2497 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2498 // calculate STK 2499 if (IS_RESPONDER(connection->sm_role)){ 2500 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2501 } else { 2502 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2503 } 2504 connection->sm_engine_state = SM_PH2_W4_STK; 2505 sm_aes128_state = SM_AES128_ACTIVE; 2506 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2507 break; 2508 2509 case SM_PH3_Y_GET_ENC: 2510 // already busy? 2511 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2512 // PH3B2 - calculate Y from - enc 2513 // Y = dm(DHK, Rand) 2514 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2515 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2516 sm_aes128_state = SM_AES128_ACTIVE; 2517 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, connection); 2518 break; 2519 2520 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2521 uint8_t buffer[17]; 2522 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2523 reverse_128(setup->sm_local_confirm, &buffer[1]); 2524 if (IS_RESPONDER(connection->sm_role)){ 2525 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2526 } else { 2527 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2528 } 2529 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2530 sm_timeout_reset(connection); 2531 return; 2532 } 2533 #ifdef ENABLE_LE_PERIPHERAL 2534 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2535 sm_key_t stk_flipped; 2536 reverse_128(setup->sm_ltk, stk_flipped); 2537 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2538 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2539 return; 2540 } 2541 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2542 sm_key_t ltk_flipped; 2543 reverse_128(setup->sm_ltk, ltk_flipped); 2544 connection->sm_engine_state = SM_RESPONDER_IDLE; 2545 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2546 sm_done_for_handle(connection->sm_handle); 2547 return; 2548 } 2549 case SM_RESPONDER_PH4_Y_GET_ENC: 2550 // already busy? 2551 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2552 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2553 // Y = dm(DHK, Rand) 2554 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2555 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2556 sm_aes128_state = SM_AES128_ACTIVE; 2557 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, connection); 2558 return; 2559 #endif 2560 #ifdef ENABLE_LE_CENTRAL 2561 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2562 sm_key_t stk_flipped; 2563 reverse_128(setup->sm_ltk, stk_flipped); 2564 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2565 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2566 return; 2567 } 2568 #endif 2569 2570 case SM_PH3_DISTRIBUTE_KEYS: 2571 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2572 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2573 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2574 uint8_t buffer[17]; 2575 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2576 reverse_128(setup->sm_ltk, &buffer[1]); 2577 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2578 sm_timeout_reset(connection); 2579 return; 2580 } 2581 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2582 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2583 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2584 uint8_t buffer[11]; 2585 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2586 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2587 reverse_64(setup->sm_local_rand, &buffer[3]); 2588 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2589 sm_timeout_reset(connection); 2590 return; 2591 } 2592 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2593 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2594 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2595 uint8_t buffer[17]; 2596 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2597 reverse_128(sm_persistent_irk, &buffer[1]); 2598 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2599 sm_timeout_reset(connection); 2600 return; 2601 } 2602 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2603 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2604 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2605 bd_addr_t local_address; 2606 uint8_t buffer[8]; 2607 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2608 switch (gap_random_address_get_mode()){ 2609 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2610 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2611 // public or static random 2612 gap_le_get_own_address(&buffer[1], local_address); 2613 break; 2614 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2615 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2616 // fallback to public 2617 gap_local_bd_addr(local_address); 2618 buffer[1] = 0; 2619 break; 2620 } 2621 reverse_bd_addr(local_address, &buffer[2]); 2622 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2623 sm_timeout_reset(connection); 2624 return; 2625 } 2626 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2627 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2628 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2629 2630 #ifdef ENABLE_LE_SIGNED_WRITE 2631 // hack to reproduce test runs 2632 if (test_use_fixed_local_csrk){ 2633 memset(setup->sm_local_csrk, 0xcc, 16); 2634 } 2635 2636 // store local CSRK 2637 if (setup->sm_le_device_index >= 0){ 2638 log_info("sm: store local CSRK"); 2639 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2640 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2641 } 2642 #endif 2643 2644 uint8_t buffer[17]; 2645 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2646 reverse_128(setup->sm_local_csrk, &buffer[1]); 2647 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2648 sm_timeout_reset(connection); 2649 return; 2650 } 2651 2652 // keys are sent 2653 if (IS_RESPONDER(connection->sm_role)){ 2654 // slave -> receive master keys if any 2655 if (sm_key_distribution_all_received(connection)){ 2656 sm_key_distribution_handle_all_received(connection); 2657 connection->sm_engine_state = SM_RESPONDER_IDLE; 2658 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2659 sm_done_for_handle(connection->sm_handle); 2660 } else { 2661 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2662 } 2663 } else { 2664 // master -> all done 2665 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2666 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2667 sm_done_for_handle(connection->sm_handle); 2668 } 2669 break; 2670 2671 default: 2672 break; 2673 } 2674 2675 // check again if active connection was released 2676 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2677 } 2678 } 2679 2680 // sm_aes128_state stays active 2681 static void sm_handle_encryption_result_enc_a(void *arg){ 2682 sm_connection_t * connection = (sm_connection_t*) arg; 2683 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2684 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, connection); 2685 } 2686 2687 static void sm_handle_encryption_result_enc_b(void *arg){ 2688 sm_connection_t * connection = (sm_connection_t*) arg; 2689 sm_aes128_state = SM_AES128_IDLE; 2690 log_info_key("c1!", setup->sm_local_confirm); 2691 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2692 sm_run(); 2693 } 2694 2695 // sm_aes128_state stays active 2696 static void sm_handle_encryption_result_enc_c(void *arg){ 2697 sm_connection_t * connection = (sm_connection_t*) arg; 2698 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2699 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, connection); 2700 } 2701 2702 static void sm_handle_encryption_result_enc_d(void * arg){ 2703 sm_connection_t * connection = (sm_connection_t*) arg; 2704 sm_aes128_state = SM_AES128_IDLE; 2705 log_info_key("c1!", sm_aes128_ciphertext); 2706 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2707 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2708 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2709 sm_run(); 2710 return; 2711 } 2712 if (IS_RESPONDER(connection->sm_role)){ 2713 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2714 sm_run(); 2715 } else { 2716 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2717 sm_aes128_state = SM_AES128_ACTIVE; 2718 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, connection); 2719 } 2720 } 2721 2722 static void sm_handle_encryption_result_enc_stk(void *arg){ 2723 sm_connection_t * connection = (sm_connection_t*) arg; 2724 sm_aes128_state = SM_AES128_IDLE; 2725 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2726 log_info_key("stk", setup->sm_ltk); 2727 if (IS_RESPONDER(connection->sm_role)){ 2728 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2729 } else { 2730 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2731 } 2732 sm_run(); 2733 } 2734 2735 // sm_aes128_state stays active 2736 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2737 sm_connection_t * connection = (sm_connection_t*) arg; 2738 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2739 log_info_hex16("y", setup->sm_local_y); 2740 // PH3B3 - calculate EDIV 2741 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2742 log_info_hex16("ediv", setup->sm_local_ediv); 2743 // PH3B4 - calculate LTK - enc 2744 // LTK = d1(ER, DIV, 0)) 2745 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2746 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, connection); 2747 } 2748 2749 #ifdef ENABLE_LE_PERIPHERAL 2750 // sm_aes128_state stays active 2751 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2752 sm_connection_t * connection = (sm_connection_t*) arg; 2753 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2754 log_info_hex16("y", setup->sm_local_y); 2755 2756 // PH3B3 - calculate DIV 2757 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2758 log_info_hex16("ediv", setup->sm_local_ediv); 2759 // PH3B4 - calculate LTK - enc 2760 // LTK = d1(ER, DIV, 0)) 2761 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2762 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, connection); 2763 } 2764 #endif 2765 2766 // sm_aes128_state stays active 2767 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2768 sm_connection_t * connection = (sm_connection_t*) arg; 2769 log_info_key("ltk", setup->sm_ltk); 2770 // calc CSRK next 2771 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2772 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, connection); 2773 } 2774 2775 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2776 sm_connection_t * connection = (sm_connection_t*) arg; 2777 sm_aes128_state = SM_AES128_IDLE; 2778 log_info_key("csrk", setup->sm_local_csrk); 2779 if (setup->sm_key_distribution_send_set){ 2780 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2781 } else { 2782 // no keys to send, just continue 2783 if (IS_RESPONDER(connection->sm_role)){ 2784 // slave -> receive master keys 2785 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2786 } else { 2787 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2788 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2789 } else { 2790 // master -> all done 2791 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2792 sm_done_for_handle(connection->sm_handle); 2793 } 2794 } 2795 } 2796 sm_run(); 2797 } 2798 2799 #ifdef ENABLE_LE_PERIPHERAL 2800 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2801 sm_connection_t * connection = (sm_connection_t*) arg; 2802 sm_aes128_state = SM_AES128_IDLE; 2803 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2804 log_info_key("ltk", setup->sm_ltk); 2805 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2806 sm_run(); 2807 } 2808 #endif 2809 2810 static void sm_handle_encryption_result_address_resolution(void *arg){ 2811 UNUSED(arg); 2812 sm_aes128_state = SM_AES128_IDLE; 2813 sm_address_resolution_ah_calculation_active = 0; 2814 // compare calulated address against connecting device 2815 uint8_t * hash = &sm_aes128_ciphertext[13]; 2816 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2817 log_info("LE Device Lookup: matched resolvable private address"); 2818 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2819 sm_run(); 2820 return; 2821 } 2822 // no match, try next 2823 sm_address_resolution_test++; 2824 sm_run(); 2825 } 2826 2827 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2828 UNUSED(arg); 2829 sm_aes128_state = SM_AES128_IDLE; 2830 log_info_key("irk", sm_persistent_irk); 2831 dkg_state = DKG_CALC_DHK; 2832 sm_run(); 2833 } 2834 2835 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2836 UNUSED(arg); 2837 sm_aes128_state = SM_AES128_IDLE; 2838 log_info_key("dhk", sm_persistent_dhk); 2839 dkg_state = DKG_READY; 2840 sm_run(); 2841 } 2842 2843 static void sm_handle_encryption_result_rau(void *arg){ 2844 UNUSED(arg); 2845 sm_aes128_state = SM_AES128_IDLE; 2846 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2847 rau_state = RAU_SET_ADDRESS; 2848 sm_run(); 2849 } 2850 2851 static void sm_handle_random_result_rau(void * arg){ 2852 UNUSED(arg); 2853 // non-resolvable vs. resolvable 2854 switch (gap_random_adress_type){ 2855 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2856 // resolvable: use random as prand and calc address hash 2857 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2858 sm_random_address[0] &= 0x3f; 2859 sm_random_address[0] |= 0x40; 2860 rau_state = RAU_GET_ENC; 2861 break; 2862 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2863 default: 2864 // "The two most significant bits of the address shall be equal to ‘0’"" 2865 sm_random_address[0] &= 0x3f; 2866 rau_state = RAU_SET_ADDRESS; 2867 break; 2868 } 2869 sm_run(); 2870 } 2871 2872 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2873 static void sm_handle_random_result_sc_get_random(void * arg){ 2874 sm_connection_t * connection = (sm_connection_t*) arg; 2875 2876 // OOB 2877 if (setup->sm_stk_generation_method == OOB){ 2878 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2879 sm_run(); 2880 return; 2881 } 2882 2883 // initiator & jw/nc -> send pairing random 2884 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2885 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2886 } else { 2887 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2888 } 2889 sm_run(); 2890 } 2891 #endif 2892 2893 static void sm_handle_random_result_ph2_random(void * arg){ 2894 sm_connection_t * connection = (sm_connection_t*) arg; 2895 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2896 sm_run(); 2897 } 2898 2899 static void sm_handle_random_result_ph2_tk(void * arg){ 2900 sm_connection_t * connection = (sm_connection_t*) arg; 2901 sm_reset_tk(); 2902 uint32_t tk; 2903 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2904 // map random to 0-999999 without speding much cycles on a modulus operation 2905 tk = little_endian_read_32(sm_random_data,0); 2906 tk = tk & 0xfffff; // 1048575 2907 if (tk >= 999999){ 2908 tk = tk - 999999; 2909 } 2910 } else { 2911 // override with pre-defined passkey 2912 tk = sm_fixed_passkey_in_display_role; 2913 } 2914 big_endian_store_32(setup->sm_tk, 12, tk); 2915 if (IS_RESPONDER(connection->sm_role)){ 2916 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2917 } else { 2918 if (setup->sm_use_secure_connections){ 2919 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2920 } else { 2921 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2922 sm_trigger_user_response(connection); 2923 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2924 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2925 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, connection); 2926 } 2927 } 2928 } 2929 sm_run(); 2930 } 2931 2932 static void sm_handle_random_result_ph3_div(void * arg){ 2933 sm_connection_t * connection = (sm_connection_t*) arg; 2934 // use 16 bit from random value as div 2935 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2936 log_info_hex16("div", setup->sm_local_div); 2937 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2938 sm_run(); 2939 } 2940 2941 static void sm_handle_random_result_ph3_random(void * arg){ 2942 sm_connection_t * connection = (sm_connection_t*) arg; 2943 reverse_64(sm_random_data, setup->sm_local_rand); 2944 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2945 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2946 // no db for authenticated flag hack: store flag in bit 4 of LSB 2947 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2948 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, connection); 2949 } 2950 static void sm_validate_er_ir(void){ 2951 // warn about default ER/IR 2952 int warning = 0; 2953 if (sm_ir_is_default()){ 2954 warning = 1; 2955 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 2956 } 2957 if (sm_er_is_default()){ 2958 warning = 1; 2959 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 2960 } 2961 if (warning) { 2962 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 2963 } 2964 } 2965 2966 static void sm_handle_random_result_ir(void *arg){ 2967 sm_persistent_keys_random_active = 0; 2968 if (arg){ 2969 // key generated, store in tlv 2970 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2971 log_info("Generated IR key. Store in TLV status: %d", status); 2972 } 2973 log_info_key("IR", sm_persistent_ir); 2974 dkg_state = DKG_CALC_IRK; 2975 sm_run(); 2976 } 2977 2978 static void sm_handle_random_result_er(void *arg){ 2979 sm_persistent_keys_random_active = 0; 2980 if (arg){ 2981 // key generated, store in tlv 2982 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 2983 log_info("Generated ER key. Store in TLV status: %d", status); 2984 } 2985 log_info_key("ER", sm_persistent_er); 2986 2987 // try load ir 2988 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 2989 if (key_size == 16){ 2990 // ok, let's continue 2991 log_info("IR from TLV"); 2992 sm_handle_random_result_ir( NULL ); 2993 } else { 2994 // invalid, generate new random one 2995 sm_persistent_keys_random_active = 1; 2996 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 2997 } 2998 } 2999 3000 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3001 3002 UNUSED(channel); // ok: there is no channel 3003 UNUSED(size); // ok: fixed format HCI events 3004 3005 sm_connection_t * sm_conn; 3006 hci_con_handle_t con_handle; 3007 3008 switch (packet_type) { 3009 3010 case HCI_EVENT_PACKET: 3011 switch (hci_event_packet_get_type(packet)) { 3012 3013 case BTSTACK_EVENT_STATE: 3014 // bt stack activated, get started 3015 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3016 log_info("HCI Working!"); 3017 3018 // setup IR/ER with TLV 3019 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3020 if (sm_tlv_impl){ 3021 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3022 if (key_size == 16){ 3023 // ok, let's continue 3024 log_info("ER from TLV"); 3025 sm_handle_random_result_er( NULL ); 3026 } else { 3027 // invalid, generate random one 3028 sm_persistent_keys_random_active = 1; 3029 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3030 } 3031 } else { 3032 sm_validate_er_ir(); 3033 dkg_state = DKG_CALC_IRK; 3034 } 3035 } 3036 break; 3037 3038 case HCI_EVENT_LE_META: 3039 switch (packet[2]) { 3040 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3041 3042 log_info("sm: connected"); 3043 3044 if (packet[3]) return; // connection failed 3045 3046 con_handle = little_endian_read_16(packet, 4); 3047 sm_conn = sm_get_connection_for_handle(con_handle); 3048 if (!sm_conn) break; 3049 3050 sm_conn->sm_handle = con_handle; 3051 sm_conn->sm_role = packet[6]; 3052 sm_conn->sm_peer_addr_type = packet[7]; 3053 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3054 3055 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3056 3057 // reset security properties 3058 sm_conn->sm_connection_encrypted = 0; 3059 sm_conn->sm_connection_authenticated = 0; 3060 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3061 sm_conn->sm_le_db_index = -1; 3062 3063 // prepare CSRK lookup (does not involve setup) 3064 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3065 3066 // just connected -> everything else happens in sm_run() 3067 if (IS_RESPONDER(sm_conn->sm_role)){ 3068 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3069 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3070 if (sm_slave_request_security) { 3071 // request security if requested by app 3072 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3073 } else { 3074 // otherwise, wait for pairing request 3075 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3076 } 3077 } 3078 break; 3079 } else { 3080 // master 3081 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3082 } 3083 break; 3084 3085 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3086 con_handle = little_endian_read_16(packet, 3); 3087 sm_conn = sm_get_connection_for_handle(con_handle); 3088 if (!sm_conn) break; 3089 3090 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3091 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3092 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3093 break; 3094 } 3095 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3096 // PH2 SEND LTK as we need to exchange keys in PH3 3097 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3098 break; 3099 } 3100 3101 // store rand and ediv 3102 reverse_64(&packet[5], sm_conn->sm_local_rand); 3103 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3104 3105 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3106 // potentially stored LTK is from the master 3107 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3108 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3109 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3110 break; 3111 } 3112 // additionally check if remote is in LE Device DB if requested 3113 switch(sm_conn->sm_irk_lookup_state){ 3114 case IRK_LOOKUP_FAILED: 3115 log_info("LTK Request: device not in device db"); 3116 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3117 break; 3118 case IRK_LOOKUP_SUCCEEDED: 3119 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3120 break; 3121 default: 3122 // wait for irk look doen 3123 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3124 break; 3125 } 3126 break; 3127 } 3128 3129 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3130 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3131 #else 3132 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3133 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3134 #endif 3135 break; 3136 3137 default: 3138 break; 3139 } 3140 break; 3141 3142 case HCI_EVENT_ENCRYPTION_CHANGE: 3143 con_handle = little_endian_read_16(packet, 3); 3144 sm_conn = sm_get_connection_for_handle(con_handle); 3145 if (!sm_conn) break; 3146 3147 sm_conn->sm_connection_encrypted = packet[5]; 3148 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3149 sm_conn->sm_actual_encryption_key_size); 3150 log_info("event handler, state %u", sm_conn->sm_engine_state); 3151 3152 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3153 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3154 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3155 // notify client, if pairing was requested before 3156 if (sm_conn->sm_pairing_requested){ 3157 sm_conn->sm_pairing_requested = 0; 3158 if (sm_conn->sm_connection_encrypted){ 3159 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3160 } else { 3161 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3162 } 3163 } 3164 sm_done_for_handle(sm_conn->sm_handle); 3165 break; 3166 } 3167 3168 if (!sm_conn->sm_connection_encrypted) break; 3169 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3170 3171 // continue pairing 3172 switch (sm_conn->sm_engine_state){ 3173 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3174 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3175 sm_done_for_handle(sm_conn->sm_handle); 3176 break; 3177 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3178 if (IS_RESPONDER(sm_conn->sm_role)){ 3179 // slave 3180 if (setup->sm_use_secure_connections){ 3181 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3182 } else { 3183 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3184 } 3185 } else { 3186 // master 3187 if (sm_key_distribution_all_received(sm_conn)){ 3188 // skip receiving keys as there are none 3189 sm_key_distribution_handle_all_received(sm_conn); 3190 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3191 } else { 3192 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3193 } 3194 } 3195 break; 3196 default: 3197 break; 3198 } 3199 break; 3200 3201 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3202 con_handle = little_endian_read_16(packet, 3); 3203 sm_conn = sm_get_connection_for_handle(con_handle); 3204 if (!sm_conn) break; 3205 3206 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3207 log_info("event handler, state %u", sm_conn->sm_engine_state); 3208 // continue if part of initial pairing 3209 switch (sm_conn->sm_engine_state){ 3210 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3211 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3212 sm_done_for_handle(sm_conn->sm_handle); 3213 break; 3214 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3215 if (IS_RESPONDER(sm_conn->sm_role)){ 3216 // slave 3217 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3218 } else { 3219 // master 3220 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3221 } 3222 break; 3223 default: 3224 break; 3225 } 3226 break; 3227 3228 3229 case HCI_EVENT_DISCONNECTION_COMPLETE: 3230 con_handle = little_endian_read_16(packet, 3); 3231 sm_done_for_handle(con_handle); 3232 sm_conn = sm_get_connection_for_handle(con_handle); 3233 if (!sm_conn) break; 3234 3235 // delete stored bonding on disconnect with authentication failure in ph0 3236 if (sm_conn->sm_role == 0 3237 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3238 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3239 le_device_db_remove(sm_conn->sm_le_db_index); 3240 } 3241 3242 // pairing failed, if it was ongoing 3243 switch (sm_conn->sm_engine_state){ 3244 case SM_GENERAL_IDLE: 3245 case SM_INITIATOR_CONNECTED: 3246 case SM_RESPONDER_IDLE: 3247 break; 3248 default: 3249 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3250 break; 3251 } 3252 3253 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3254 sm_conn->sm_handle = 0; 3255 break; 3256 3257 case HCI_EVENT_COMMAND_COMPLETE: 3258 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3259 // set local addr for le device db 3260 bd_addr_t addr; 3261 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3262 le_device_db_set_local_bd_addr(addr); 3263 } 3264 break; 3265 default: 3266 break; 3267 } 3268 break; 3269 default: 3270 break; 3271 } 3272 3273 sm_run(); 3274 } 3275 3276 static inline int sm_calc_actual_encryption_key_size(int other){ 3277 if (other < sm_min_encryption_key_size) return 0; 3278 if (other < sm_max_encryption_key_size) return other; 3279 return sm_max_encryption_key_size; 3280 } 3281 3282 3283 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3284 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3285 switch (method){ 3286 case JUST_WORKS: 3287 case NUMERIC_COMPARISON: 3288 return 1; 3289 default: 3290 return 0; 3291 } 3292 } 3293 // responder 3294 3295 static int sm_passkey_used(stk_generation_method_t method){ 3296 switch (method){ 3297 case PK_RESP_INPUT: 3298 return 1; 3299 default: 3300 return 0; 3301 } 3302 } 3303 3304 static int sm_passkey_entry(stk_generation_method_t method){ 3305 switch (method){ 3306 case PK_RESP_INPUT: 3307 case PK_INIT_INPUT: 3308 case PK_BOTH_INPUT: 3309 return 1; 3310 default: 3311 return 0; 3312 } 3313 } 3314 3315 #endif 3316 3317 /** 3318 * @return ok 3319 */ 3320 static int sm_validate_stk_generation_method(void){ 3321 // check if STK generation method is acceptable by client 3322 switch (setup->sm_stk_generation_method){ 3323 case JUST_WORKS: 3324 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3325 case PK_RESP_INPUT: 3326 case PK_INIT_INPUT: 3327 case PK_BOTH_INPUT: 3328 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3329 case OOB: 3330 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3331 case NUMERIC_COMPARISON: 3332 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3333 default: 3334 return 0; 3335 } 3336 } 3337 3338 // size of complete sm_pdu used to validate input 3339 static const uint8_t sm_pdu_size[] = { 3340 0, // 0x00 invalid opcode 3341 7, // 0x01 pairing request 3342 7, // 0x02 pairing response 3343 17, // 0x03 pairing confirm 3344 17, // 0x04 pairing random 3345 2, // 0x05 pairing failed 3346 17, // 0x06 encryption information 3347 11, // 0x07 master identification 3348 17, // 0x08 identification information 3349 8, // 0x09 identify address information 3350 17, // 0x0a signing information 3351 2, // 0x0b security request 3352 65, // 0x0c pairing public key 3353 17, // 0x0d pairing dhk check 3354 2, // 0x0e keypress notification 3355 }; 3356 3357 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3358 3359 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3360 sm_run(); 3361 } 3362 3363 if (packet_type != SM_DATA_PACKET) return; 3364 if (size == 0) return; 3365 3366 uint8_t sm_pdu_code = packet[0]; 3367 3368 // validate pdu size 3369 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3370 if (sm_pdu_size[sm_pdu_code] != size) return; 3371 3372 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3373 if (!sm_conn) return; 3374 3375 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3376 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3377 sm_done_for_handle(con_handle); 3378 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3379 return; 3380 } 3381 3382 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3383 3384 int err; 3385 UNUSED(err); 3386 3387 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3388 uint8_t buffer[5]; 3389 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3390 buffer[1] = 3; 3391 little_endian_store_16(buffer, 2, con_handle); 3392 buffer[4] = packet[1]; 3393 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3394 return; 3395 } 3396 3397 switch (sm_conn->sm_engine_state){ 3398 3399 // a sm timeout requries a new physical connection 3400 case SM_GENERAL_TIMEOUT: 3401 return; 3402 3403 #ifdef ENABLE_LE_CENTRAL 3404 3405 // Initiator 3406 case SM_INITIATOR_CONNECTED: 3407 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3408 sm_pdu_received_in_wrong_state(sm_conn); 3409 break; 3410 } 3411 3412 // IRK complete? 3413 switch (sm_conn->sm_irk_lookup_state){ 3414 case IRK_LOOKUP_FAILED: 3415 case IRK_LOOKUP_SUCCEEDED: 3416 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3417 break; 3418 default: 3419 break; 3420 } 3421 3422 // otherwise, store security request 3423 sm_conn->sm_security_request_received = 1; 3424 break; 3425 3426 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3427 // Core 5, Vol 3, Part H, 2.4.6: 3428 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3429 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3430 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3431 log_info("Ignoring Security Request"); 3432 break; 3433 } 3434 3435 // all other pdus are incorrect 3436 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3437 sm_pdu_received_in_wrong_state(sm_conn); 3438 break; 3439 } 3440 3441 // store pairing request 3442 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3443 err = sm_stk_generation_init(sm_conn); 3444 3445 #ifdef ENABLE_TESTING_SUPPORT 3446 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3447 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3448 err = test_pairing_failure; 3449 } 3450 #endif 3451 3452 if (err){ 3453 setup->sm_pairing_failed_reason = err; 3454 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3455 break; 3456 } 3457 3458 // generate random number first, if we need to show passkey 3459 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3460 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, sm_conn); 3461 break; 3462 } 3463 3464 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3465 if (setup->sm_use_secure_connections){ 3466 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3467 if (setup->sm_stk_generation_method == JUST_WORKS){ 3468 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3469 sm_trigger_user_response(sm_conn); 3470 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3471 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3472 } 3473 } else { 3474 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3475 } 3476 break; 3477 } 3478 #endif 3479 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3480 sm_trigger_user_response(sm_conn); 3481 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3482 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3483 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3484 } 3485 break; 3486 3487 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3488 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3489 sm_pdu_received_in_wrong_state(sm_conn); 3490 break; 3491 } 3492 3493 // store s_confirm 3494 reverse_128(&packet[1], setup->sm_peer_confirm); 3495 3496 #ifdef ENABLE_TESTING_SUPPORT 3497 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3498 log_info("testing_support: reset confirm value"); 3499 memset(setup->sm_peer_confirm, 0, 16); 3500 } 3501 #endif 3502 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3503 break; 3504 3505 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3506 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3507 sm_pdu_received_in_wrong_state(sm_conn); 3508 break;; 3509 } 3510 3511 // received random value 3512 reverse_128(&packet[1], setup->sm_peer_random); 3513 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3514 break; 3515 #endif 3516 3517 #ifdef ENABLE_LE_PERIPHERAL 3518 // Responder 3519 case SM_RESPONDER_IDLE: 3520 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3521 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3522 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3523 sm_pdu_received_in_wrong_state(sm_conn); 3524 break;; 3525 } 3526 3527 // store pairing request 3528 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3529 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3530 break; 3531 #endif 3532 3533 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3534 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3535 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3536 sm_pdu_received_in_wrong_state(sm_conn); 3537 break; 3538 } 3539 3540 // store public key for DH Key calculation 3541 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3542 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3543 3544 // validate public key 3545 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3546 if (err){ 3547 log_error("sm: peer public key invalid %x", err); 3548 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3549 break; 3550 } 3551 3552 // start calculating dhkey 3553 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, sm_conn); 3554 3555 3556 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3557 if (IS_RESPONDER(sm_conn->sm_role)){ 3558 // responder 3559 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3560 } else { 3561 // initiator 3562 // stk generation method 3563 // passkey entry: notify app to show passkey or to request passkey 3564 switch (setup->sm_stk_generation_method){ 3565 case JUST_WORKS: 3566 case NUMERIC_COMPARISON: 3567 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3568 break; 3569 case PK_RESP_INPUT: 3570 sm_sc_start_calculating_local_confirm(sm_conn); 3571 break; 3572 case PK_INIT_INPUT: 3573 case PK_BOTH_INPUT: 3574 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3575 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3576 break; 3577 } 3578 sm_sc_start_calculating_local_confirm(sm_conn); 3579 break; 3580 case OOB: 3581 // generate Nx 3582 log_info("Generate Na"); 3583 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3584 break; 3585 } 3586 } 3587 break; 3588 3589 case SM_SC_W4_CONFIRMATION: 3590 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3591 sm_pdu_received_in_wrong_state(sm_conn); 3592 break; 3593 } 3594 // received confirm value 3595 reverse_128(&packet[1], setup->sm_peer_confirm); 3596 3597 #ifdef ENABLE_TESTING_SUPPORT 3598 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3599 log_info("testing_support: reset confirm value"); 3600 memset(setup->sm_peer_confirm, 0, 16); 3601 } 3602 #endif 3603 if (IS_RESPONDER(sm_conn->sm_role)){ 3604 // responder 3605 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3606 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3607 // still waiting for passkey 3608 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3609 break; 3610 } 3611 } 3612 sm_sc_start_calculating_local_confirm(sm_conn); 3613 } else { 3614 // initiator 3615 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3616 // sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3617 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, sm_conn); 3618 } else { 3619 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3620 } 3621 } 3622 break; 3623 3624 case SM_SC_W4_PAIRING_RANDOM: 3625 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3626 sm_pdu_received_in_wrong_state(sm_conn); 3627 break; 3628 } 3629 3630 // received random value 3631 reverse_128(&packet[1], setup->sm_peer_nonce); 3632 3633 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3634 // only check for JUST WORK/NC in initiator role OR passkey entry 3635 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3636 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3637 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3638 break; 3639 } 3640 3641 // OOB 3642 if (setup->sm_stk_generation_method == OOB){ 3643 3644 // setup local random, set to zero if remote did not receive our data 3645 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3646 if (IS_RESPONDER(sm_conn->sm_role)){ 3647 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3648 log_info("Reset rb as A does not have OOB data"); 3649 memset(setup->sm_rb, 0, 16); 3650 } else { 3651 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3652 log_info("Use stored rb"); 3653 log_info_hexdump(setup->sm_rb, 16); 3654 } 3655 } else { 3656 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3657 log_info("Reset ra as B does not have OOB data"); 3658 memset(setup->sm_ra, 0, 16); 3659 } else { 3660 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3661 log_info("Use stored ra"); 3662 log_info_hexdump(setup->sm_ra, 16); 3663 } 3664 } 3665 3666 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3667 if (setup->sm_have_oob_data){ 3668 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3669 break; 3670 } 3671 } 3672 3673 // TODO: we only get here for Responder role with JW/NC 3674 sm_sc_state_after_receiving_random(sm_conn); 3675 break; 3676 3677 case SM_SC_W2_CALCULATE_G2: 3678 case SM_SC_W4_CALCULATE_G2: 3679 case SM_SC_W4_CALCULATE_DHKEY: 3680 case SM_SC_W2_CALCULATE_F5_SALT: 3681 case SM_SC_W4_CALCULATE_F5_SALT: 3682 case SM_SC_W2_CALCULATE_F5_MACKEY: 3683 case SM_SC_W4_CALCULATE_F5_MACKEY: 3684 case SM_SC_W2_CALCULATE_F5_LTK: 3685 case SM_SC_W4_CALCULATE_F5_LTK: 3686 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3687 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3688 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3689 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3690 sm_pdu_received_in_wrong_state(sm_conn); 3691 break; 3692 } 3693 // store DHKey Check 3694 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3695 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3696 3697 // have we been only waiting for dhkey check command? 3698 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3699 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3700 } 3701 break; 3702 #endif 3703 3704 #ifdef ENABLE_LE_PERIPHERAL 3705 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3706 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3707 sm_pdu_received_in_wrong_state(sm_conn); 3708 break; 3709 } 3710 3711 // received confirm value 3712 reverse_128(&packet[1], setup->sm_peer_confirm); 3713 3714 #ifdef ENABLE_TESTING_SUPPORT 3715 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3716 log_info("testing_support: reset confirm value"); 3717 memset(setup->sm_peer_confirm, 0, 16); 3718 } 3719 #endif 3720 // notify client to hide shown passkey 3721 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3722 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3723 } 3724 3725 // handle user cancel pairing? 3726 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3727 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3728 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3729 break; 3730 } 3731 3732 // wait for user action? 3733 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3734 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3735 break; 3736 } 3737 3738 // calculate and send local_confirm 3739 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 3740 break; 3741 3742 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3743 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3744 sm_pdu_received_in_wrong_state(sm_conn); 3745 break;; 3746 } 3747 3748 // received random value 3749 reverse_128(&packet[1], setup->sm_peer_random); 3750 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3751 break; 3752 #endif 3753 3754 case SM_PH3_RECEIVE_KEYS: 3755 switch(sm_pdu_code){ 3756 case SM_CODE_ENCRYPTION_INFORMATION: 3757 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3758 reverse_128(&packet[1], setup->sm_peer_ltk); 3759 break; 3760 3761 case SM_CODE_MASTER_IDENTIFICATION: 3762 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3763 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3764 reverse_64(&packet[3], setup->sm_peer_rand); 3765 break; 3766 3767 case SM_CODE_IDENTITY_INFORMATION: 3768 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3769 reverse_128(&packet[1], setup->sm_peer_irk); 3770 break; 3771 3772 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3773 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3774 setup->sm_peer_addr_type = packet[1]; 3775 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3776 break; 3777 3778 case SM_CODE_SIGNING_INFORMATION: 3779 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3780 reverse_128(&packet[1], setup->sm_peer_csrk); 3781 break; 3782 default: 3783 // Unexpected PDU 3784 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3785 break; 3786 } 3787 // done with key distribution? 3788 if (sm_key_distribution_all_received(sm_conn)){ 3789 3790 sm_key_distribution_handle_all_received(sm_conn); 3791 3792 if (IS_RESPONDER(sm_conn->sm_role)){ 3793 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3794 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3795 } else { 3796 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3797 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3798 sm_done_for_handle(sm_conn->sm_handle); 3799 } 3800 } else { 3801 if (setup->sm_use_secure_connections){ 3802 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3803 } else { 3804 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, sm_conn); 3805 } 3806 } 3807 } 3808 break; 3809 default: 3810 // Unexpected PDU 3811 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3812 break; 3813 } 3814 3815 // try to send preparared packet 3816 sm_run(); 3817 } 3818 3819 // Security Manager Client API 3820 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3821 sm_get_oob_data = get_oob_data_callback; 3822 } 3823 3824 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)){ 3825 sm_get_sc_oob_data = get_sc_oob_data_callback; 3826 } 3827 3828 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3829 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3830 } 3831 3832 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3833 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3834 } 3835 3836 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3837 sm_min_encryption_key_size = min_size; 3838 sm_max_encryption_key_size = max_size; 3839 } 3840 3841 void sm_set_authentication_requirements(uint8_t auth_req){ 3842 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3843 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3844 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3845 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3846 } 3847 #endif 3848 sm_auth_req = auth_req; 3849 } 3850 3851 void sm_set_io_capabilities(io_capability_t io_capability){ 3852 sm_io_capabilities = io_capability; 3853 } 3854 3855 #ifdef ENABLE_LE_PERIPHERAL 3856 void sm_set_request_security(int enable){ 3857 sm_slave_request_security = enable; 3858 } 3859 #endif 3860 3861 void sm_set_er(sm_key_t er){ 3862 memcpy(sm_persistent_er, er, 16); 3863 } 3864 3865 void sm_set_ir(sm_key_t ir){ 3866 memcpy(sm_persistent_ir, ir, 16); 3867 } 3868 3869 // Testing support only 3870 void sm_test_set_irk(sm_key_t irk){ 3871 memcpy(sm_persistent_irk, irk, 16); 3872 dkg_state = DKG_CALC_DHK; 3873 } 3874 3875 void sm_test_use_fixed_local_csrk(void){ 3876 test_use_fixed_local_csrk = 1; 3877 } 3878 3879 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3880 static void sm_ec_generated(void * arg){ 3881 UNUSED(arg); 3882 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3883 // trigger pairing if pending for ec key 3884 sm_run(); 3885 } 3886 static void sm_ec_generate_new_key(void){ 3887 log_info("sm: generate new ec key"); 3888 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3889 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3890 } 3891 #endif 3892 3893 #ifdef ENABLE_TESTING_SUPPORT 3894 void sm_test_set_pairing_failure(int reason){ 3895 test_pairing_failure = reason; 3896 } 3897 #endif 3898 3899 void sm_init(void){ 3900 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3901 sm_er_ir_set_default(); 3902 3903 // defaults 3904 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3905 | SM_STK_GENERATION_METHOD_OOB 3906 | SM_STK_GENERATION_METHOD_PASSKEY 3907 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3908 3909 sm_max_encryption_key_size = 16; 3910 sm_min_encryption_key_size = 7; 3911 3912 sm_fixed_passkey_in_display_role = 0xffffffff; 3913 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3914 3915 #ifdef USE_CMAC_ENGINE 3916 sm_cmac_active = 0; 3917 #endif 3918 dkg_state = DKG_W4_WORKING; 3919 rau_state = RAU_IDLE; 3920 sm_aes128_state = SM_AES128_IDLE; 3921 sm_address_resolution_test = -1; // no private address to resolve yet 3922 sm_address_resolution_ah_calculation_active = 0; 3923 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3924 sm_address_resolution_general_queue = NULL; 3925 3926 gap_random_adress_update_period = 15 * 60 * 1000L; 3927 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3928 3929 test_use_fixed_local_csrk = 0; 3930 3931 // register for HCI Events from HCI 3932 hci_event_callback_registration.callback = &sm_event_packet_handler; 3933 hci_add_event_handler(&hci_event_callback_registration); 3934 3935 // 3936 btstack_crypto_init(); 3937 3938 // init le_device_db 3939 le_device_db_init(); 3940 3941 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3942 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3943 3944 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3945 sm_ec_generate_new_key(); 3946 #endif 3947 } 3948 3949 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 3950 sm_fixed_passkey_in_display_role = passkey; 3951 } 3952 3953 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 3954 sm_reconstruct_ltk_without_le_device_db_entry = allow; 3955 } 3956 3957 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3958 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3959 if (!hci_con) return NULL; 3960 return &hci_con->sm_connection; 3961 } 3962 3963 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3964 switch (sm_conn->sm_engine_state){ 3965 case SM_GENERAL_IDLE: 3966 case SM_RESPONDER_IDLE: 3967 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3968 sm_run(); 3969 break; 3970 default: 3971 break; 3972 } 3973 } 3974 3975 /** 3976 * @brief Trigger Security Request 3977 */ 3978 void sm_send_security_request(hci_con_handle_t con_handle){ 3979 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3980 if (!sm_conn) return; 3981 sm_send_security_request_for_connection(sm_conn); 3982 } 3983 3984 // request pairing 3985 void sm_request_pairing(hci_con_handle_t con_handle){ 3986 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3987 if (!sm_conn) return; // wrong connection 3988 3989 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3990 if (IS_RESPONDER(sm_conn->sm_role)){ 3991 sm_send_security_request_for_connection(sm_conn); 3992 } else { 3993 // used as a trigger to start central/master/initiator security procedures 3994 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3995 uint8_t ltk[16]; 3996 switch (sm_conn->sm_irk_lookup_state){ 3997 case IRK_LOOKUP_SUCCEEDED: 3998 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 3999 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4000 log_info("have ltk %u", !sm_is_null_key(ltk)); 4001 // trigger 'pairing complete' event on encryption change 4002 sm_conn->sm_pairing_requested = 1; 4003 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4004 break; 4005 #endif 4006 /* explicit fall-through */ 4007 4008 case IRK_LOOKUP_FAILED: 4009 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4010 break; 4011 default: 4012 log_info("irk lookup pending"); 4013 sm_conn->sm_pairing_requested = 1; 4014 break; 4015 } 4016 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4017 sm_conn->sm_pairing_requested = 1; 4018 } 4019 } 4020 sm_run(); 4021 } 4022 4023 // called by client app on authorization request 4024 void sm_authorization_decline(hci_con_handle_t con_handle){ 4025 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4026 if (!sm_conn) return; // wrong connection 4027 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4028 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4029 } 4030 4031 void sm_authorization_grant(hci_con_handle_t con_handle){ 4032 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4033 if (!sm_conn) return; // wrong connection 4034 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4035 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4036 } 4037 4038 // GAP Bonding API 4039 4040 void sm_bonding_decline(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 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4044 log_info("decline, state %u", sm_conn->sm_engine_state); 4045 switch(sm_conn->sm_engine_state){ 4046 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4047 case SM_SC_W4_USER_RESPONSE: 4048 case SM_SC_W4_CONFIRMATION: 4049 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4050 #endif 4051 case SM_PH1_W4_USER_RESPONSE: 4052 switch (setup->sm_stk_generation_method){ 4053 case PK_RESP_INPUT: 4054 case PK_INIT_INPUT: 4055 case PK_BOTH_INPUT: 4056 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4057 break; 4058 case NUMERIC_COMPARISON: 4059 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4060 break; 4061 case JUST_WORKS: 4062 case OOB: 4063 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4064 break; 4065 } 4066 break; 4067 default: 4068 break; 4069 } 4070 sm_run(); 4071 } 4072 4073 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4074 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4075 if (!sm_conn) return; // wrong connection 4076 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4077 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4078 if (setup->sm_use_secure_connections){ 4079 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4080 } else { 4081 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4082 } 4083 } 4084 4085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4086 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4087 sm_sc_prepare_dhkey_check(sm_conn); 4088 } 4089 #endif 4090 4091 sm_run(); 4092 } 4093 4094 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4095 // for now, it's the same 4096 sm_just_works_confirm(con_handle); 4097 } 4098 4099 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4100 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4101 if (!sm_conn) return; // wrong connection 4102 sm_reset_tk(); 4103 big_endian_store_32(setup->sm_tk, 12, passkey); 4104 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4105 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4106 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, sm_conn); 4107 } 4108 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4109 memcpy(setup->sm_ra, setup->sm_tk, 16); 4110 memcpy(setup->sm_rb, setup->sm_tk, 16); 4111 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4112 sm_sc_start_calculating_local_confirm(sm_conn); 4113 } 4114 #endif 4115 sm_run(); 4116 } 4117 4118 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4119 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4120 if (!sm_conn) return; // wrong connection 4121 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4122 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4123 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4124 switch (action){ 4125 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4126 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4127 flags |= (1 << action); 4128 break; 4129 case SM_KEYPRESS_PASSKEY_CLEARED: 4130 // clear counter, keypress & erased flags + set passkey cleared 4131 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4132 break; 4133 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4134 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4135 // erase actions queued 4136 num_actions--; 4137 if (num_actions == 0){ 4138 // clear counter, keypress & erased flags 4139 flags &= 0x19; 4140 } 4141 break; 4142 } 4143 num_actions++; 4144 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4145 break; 4146 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4147 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4148 // enter actions queued 4149 num_actions--; 4150 if (num_actions == 0){ 4151 // clear counter, keypress & erased flags 4152 flags &= 0x19; 4153 } 4154 break; 4155 } 4156 num_actions++; 4157 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4158 break; 4159 default: 4160 break; 4161 } 4162 setup->sm_keypress_notification = (num_actions << 5) | flags; 4163 sm_run(); 4164 } 4165 4166 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4167 static void sm_handle_random_result_oob(void * arg){ 4168 UNUSED(arg); 4169 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4170 sm_run(); 4171 } 4172 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4173 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4174 sm_sc_oob_callback = callback; 4175 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4176 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4177 return 0; 4178 } 4179 #endif 4180 4181 /** 4182 * @brief Get Identity Resolving state 4183 * @param con_handle 4184 * @return irk_lookup_state_t 4185 */ 4186 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4187 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4188 if (!sm_conn) return IRK_LOOKUP_IDLE; 4189 return sm_conn->sm_irk_lookup_state; 4190 } 4191 4192 /** 4193 * @brief Identify device in LE Device DB 4194 * @param handle 4195 * @returns index from le_device_db or -1 if not found/identified 4196 */ 4197 int sm_le_device_index(hci_con_handle_t con_handle ){ 4198 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4199 if (!sm_conn) return -1; 4200 return sm_conn->sm_le_db_index; 4201 } 4202 4203 static int gap_random_address_type_requires_updates(void){ 4204 switch (gap_random_adress_type){ 4205 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4206 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4207 return 0; 4208 default: 4209 return 1; 4210 } 4211 } 4212 4213 static uint8_t own_address_type(void){ 4214 switch (gap_random_adress_type){ 4215 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4216 return BD_ADDR_TYPE_LE_PUBLIC; 4217 default: 4218 return BD_ADDR_TYPE_LE_RANDOM; 4219 } 4220 } 4221 4222 // GAP LE API 4223 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4224 gap_random_address_update_stop(); 4225 gap_random_adress_type = random_address_type; 4226 hci_le_set_own_address_type(own_address_type()); 4227 if (!gap_random_address_type_requires_updates()) return; 4228 gap_random_address_update_start(); 4229 gap_random_address_trigger(); 4230 } 4231 4232 gap_random_address_type_t gap_random_address_get_mode(void){ 4233 return gap_random_adress_type; 4234 } 4235 4236 void gap_random_address_set_update_period(int period_ms){ 4237 gap_random_adress_update_period = period_ms; 4238 if (!gap_random_address_type_requires_updates()) return; 4239 gap_random_address_update_stop(); 4240 gap_random_address_update_start(); 4241 } 4242 4243 void gap_random_address_set(bd_addr_t addr){ 4244 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4245 memcpy(sm_random_address, addr, 6); 4246 rau_state = RAU_SET_ADDRESS; 4247 sm_run(); 4248 } 4249 4250 #ifdef ENABLE_LE_PERIPHERAL 4251 /* 4252 * @brief Set Advertisement Paramters 4253 * @param adv_int_min 4254 * @param adv_int_max 4255 * @param adv_type 4256 * @param direct_address_type 4257 * @param direct_address 4258 * @param channel_map 4259 * @param filter_policy 4260 * 4261 * @note own_address_type is used from gap_random_address_set_mode 4262 */ 4263 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4264 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4265 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4266 direct_address_typ, direct_address, channel_map, filter_policy); 4267 } 4268 #endif 4269 4270 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4271 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4272 // wrong connection 4273 if (!sm_conn) return 0; 4274 // already encrypted 4275 if (sm_conn->sm_connection_encrypted) return 0; 4276 // only central can re-encrypt 4277 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4278 // irk status? 4279 switch(sm_conn->sm_irk_lookup_state){ 4280 case IRK_LOOKUP_FAILED: 4281 // done, cannot setup encryption 4282 return 0; 4283 case IRK_LOOKUP_SUCCEEDED: 4284 break; 4285 default: 4286 // IR Lookup pending 4287 return 1; 4288 } 4289 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4290 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4291 } 4292