1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_crypto.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "btstack_tlv.h" 53 #include "gap.h" 54 #include "hci.h" 55 #include "hci_dump.h" 56 #include "l2cap.h" 57 58 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 59 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 60 #endif 61 62 // assert SM Public Key can be sent/received 63 #ifdef ENABLE_LE_SECURE_CONNECTIONS 64 #if HCI_ACL_PAYLOAD_SIZE < 69 65 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 66 #endif 67 #endif 68 69 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 70 #define IS_RESPONDER(role) (role) 71 #else 72 #ifdef ENABLE_LE_CENTRAL 73 // only central - never responder (avoid 'unused variable' warnings) 74 #define IS_RESPONDER(role) (0 && role) 75 #else 76 // only peripheral - always responder (avoid 'unused variable' warnings) 77 #define IS_RESPONDER(role) (1 || role) 78 #endif 79 #endif 80 81 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 82 #define USE_CMAC_ENGINE 83 #endif 84 85 #define BTSTACK_TAG32(A,B,C,D) ((A << 24) | (B << 16) | (C << 8) | D) 86 87 // 88 // SM internal types and globals 89 // 90 91 typedef enum { 92 DKG_W4_WORKING, 93 DKG_CALC_IRK, 94 DKG_CALC_DHK, 95 DKG_READY 96 } derived_key_generation_t; 97 98 typedef enum { 99 RAU_IDLE, 100 RAU_GET_RANDOM, 101 RAU_W4_RANDOM, 102 RAU_GET_ENC, 103 RAU_W4_ENC, 104 RAU_SET_ADDRESS, 105 } random_address_update_t; 106 107 typedef enum { 108 CMAC_IDLE, 109 CMAC_CALC_SUBKEYS, 110 CMAC_W4_SUBKEYS, 111 CMAC_CALC_MI, 112 CMAC_W4_MI, 113 CMAC_CALC_MLAST, 114 CMAC_W4_MLAST 115 } cmac_state_t; 116 117 typedef enum { 118 JUST_WORKS, 119 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 120 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 121 PK_BOTH_INPUT, // Only input on both, both input PK 122 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 123 OOB // OOB available on one (SC) or both sides (legacy) 124 } stk_generation_method_t; 125 126 typedef enum { 127 SM_USER_RESPONSE_IDLE, 128 SM_USER_RESPONSE_PENDING, 129 SM_USER_RESPONSE_CONFIRM, 130 SM_USER_RESPONSE_PASSKEY, 131 SM_USER_RESPONSE_DECLINE 132 } sm_user_response_t; 133 134 typedef enum { 135 SM_AES128_IDLE, 136 SM_AES128_ACTIVE 137 } sm_aes128_state_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_IDLE, 141 ADDRESS_RESOLUTION_GENERAL, 142 ADDRESS_RESOLUTION_FOR_CONNECTION, 143 } address_resolution_mode_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_SUCEEDED, 147 ADDRESS_RESOLUTION_FAILED, 148 } address_resolution_event_t; 149 150 typedef enum { 151 EC_KEY_GENERATION_IDLE, 152 EC_KEY_GENERATION_ACTIVE, 153 EC_KEY_GENERATION_DONE, 154 } ec_key_generation_state_t; 155 156 typedef enum { 157 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 158 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 159 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 160 } sm_state_var_t; 161 162 typedef enum { 163 SM_SC_OOB_IDLE, 164 SM_SC_OOB_W4_RANDOM, 165 SM_SC_OOB_W2_CALC_CONFIRM, 166 SM_SC_OOB_W4_CONFIRM, 167 } sm_sc_oob_state_t; 168 169 typedef uint8_t sm_key24_t[3]; 170 typedef uint8_t sm_key56_t[7]; 171 typedef uint8_t sm_key256_t[32]; 172 173 // 174 // GLOBAL DATA 175 // 176 177 static uint8_t test_use_fixed_local_csrk; 178 179 #ifdef ENABLE_TESTING_SUPPORT 180 static uint8_t test_pairing_failure; 181 #endif 182 183 // configuration 184 static uint8_t sm_accepted_stk_generation_methods; 185 static uint8_t sm_max_encryption_key_size; 186 static uint8_t sm_min_encryption_key_size; 187 static uint8_t sm_auth_req = 0; 188 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 189 static uint8_t sm_slave_request_security; 190 static uint32_t sm_fixed_passkey_in_display_role; 191 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 192 193 #ifdef ENABLE_LE_SECURE_CONNECTIONS 194 static uint8_t sm_sc_oob_random[16]; 195 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 196 static sm_sc_oob_state_t sm_sc_oob_state; 197 #endif 198 199 200 static uint8_t sm_persistent_keys_random_active; 201 static const btstack_tlv_t * sm_tlv_impl; 202 static void * sm_tlv_context; 203 204 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 205 static sm_key_t sm_persistent_er; 206 static sm_key_t sm_persistent_ir; 207 208 // derived from sm_persistent_ir 209 static sm_key_t sm_persistent_dhk; 210 static sm_key_t sm_persistent_irk; 211 static derived_key_generation_t dkg_state; 212 213 // derived from sm_persistent_er 214 // .. 215 216 // random address update 217 static random_address_update_t rau_state; 218 static bd_addr_t sm_random_address; 219 220 #ifdef USE_CMAC_ENGINE 221 // CMAC Calculation: General 222 static btstack_crypto_aes128_cmac_t sm_cmac_request; 223 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 224 static uint8_t sm_cmac_active; 225 static uint8_t sm_cmac_hash[16]; 226 #endif 227 228 // CMAC for ATT Signed Writes 229 #ifdef ENABLE_LE_SIGNED_WRITE 230 static uint16_t sm_cmac_signed_write_message_len; 231 static uint8_t sm_cmac_signed_write_header[3]; 232 static const uint8_t * sm_cmac_signed_write_message; 233 static uint8_t sm_cmac_signed_write_sign_counter[4]; 234 #endif 235 236 // CMAC for Secure Connection functions 237 #ifdef ENABLE_LE_SECURE_CONNECTIONS 238 static sm_connection_t * sm_cmac_connection; 239 static uint8_t sm_cmac_sc_buffer[80]; 240 #endif 241 242 // resolvable private address lookup / CSRK calculation 243 static int sm_address_resolution_test; 244 static int sm_address_resolution_ah_calculation_active; 245 static uint8_t sm_address_resolution_addr_type; 246 static bd_addr_t sm_address_resolution_address; 247 static void * sm_address_resolution_context; 248 static address_resolution_mode_t sm_address_resolution_mode; 249 static btstack_linked_list_t sm_address_resolution_general_queue; 250 251 // aes128 crypto engine. 252 static sm_aes128_state_t sm_aes128_state; 253 254 // crypto 255 static btstack_crypto_random_t sm_crypto_random_request; 256 static btstack_crypto_aes128_t sm_crypto_aes128_request; 257 #ifdef ENABLE_LE_SECURE_CONNECTIONS 258 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 259 static btstack_crypto_random_t sm_crypto_random_oob_request; 260 #endif 261 262 // temp storage for random data 263 static uint8_t sm_random_data[8]; 264 static uint8_t sm_aes128_key[16]; 265 static uint8_t sm_aes128_plaintext[16]; 266 static uint8_t sm_aes128_ciphertext[16]; 267 268 // to receive hci events 269 static btstack_packet_callback_registration_t hci_event_callback_registration; 270 271 /* to dispatch sm event */ 272 static btstack_linked_list_t sm_event_handlers; 273 274 // LE Secure Connections 275 #ifdef ENABLE_LE_SECURE_CONNECTIONS 276 static ec_key_generation_state_t ec_key_generation_state; 277 static uint8_t ec_q[64]; 278 #endif 279 280 // 281 // Volume 3, Part H, Chapter 24 282 // "Security shall be initiated by the Security Manager in the device in the master role. 283 // The device in the slave role shall be the responding device." 284 // -> master := initiator, slave := responder 285 // 286 287 // data needed for security setup 288 typedef struct sm_setup_context { 289 290 btstack_timer_source_t sm_timeout; 291 292 // used in all phases 293 uint8_t sm_pairing_failed_reason; 294 295 // user response, (Phase 1 and/or 2) 296 uint8_t sm_user_response; 297 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 298 299 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 300 uint8_t sm_key_distribution_send_set; 301 uint8_t sm_key_distribution_sent_set; 302 uint8_t sm_key_distribution_received_set; 303 304 // Phase 2 (Pairing over SMP) 305 stk_generation_method_t sm_stk_generation_method; 306 sm_key_t sm_tk; 307 uint8_t sm_have_oob_data; 308 uint8_t sm_use_secure_connections; 309 310 sm_key_t sm_c1_t3_value; // c1 calculation 311 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 312 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 313 sm_key_t sm_local_random; 314 sm_key_t sm_local_confirm; 315 sm_key_t sm_peer_random; 316 sm_key_t sm_peer_confirm; 317 uint8_t sm_m_addr_type; // address and type can be removed 318 uint8_t sm_s_addr_type; // '' 319 bd_addr_t sm_m_address; // '' 320 bd_addr_t sm_s_address; // '' 321 sm_key_t sm_ltk; 322 323 uint8_t sm_state_vars; 324 #ifdef ENABLE_LE_SECURE_CONNECTIONS 325 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 326 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 327 sm_key_t sm_local_nonce; // might be combined with sm_local_random 328 sm_key_t sm_dhkey; 329 sm_key_t sm_peer_dhkey_check; 330 sm_key_t sm_local_dhkey_check; 331 sm_key_t sm_ra; 332 sm_key_t sm_rb; 333 sm_key_t sm_t; // used for f5 and h6 334 sm_key_t sm_mackey; 335 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 336 #endif 337 338 // Phase 3 339 340 // key distribution, we generate 341 uint16_t sm_local_y; 342 uint16_t sm_local_div; 343 uint16_t sm_local_ediv; 344 uint8_t sm_local_rand[8]; 345 sm_key_t sm_local_ltk; 346 sm_key_t sm_local_csrk; 347 sm_key_t sm_local_irk; 348 // sm_local_address/addr_type not needed 349 350 // key distribution, received from peer 351 uint16_t sm_peer_y; 352 uint16_t sm_peer_div; 353 uint16_t sm_peer_ediv; 354 uint8_t sm_peer_rand[8]; 355 sm_key_t sm_peer_ltk; 356 sm_key_t sm_peer_irk; 357 sm_key_t sm_peer_csrk; 358 uint8_t sm_peer_addr_type; 359 bd_addr_t sm_peer_address; 360 #ifdef ENABLE_LE_SIGNED_WRITE 361 int sm_le_device_index; 362 #endif 363 364 } sm_setup_context_t; 365 366 // 367 static sm_setup_context_t the_setup; 368 static sm_setup_context_t * setup = &the_setup; 369 370 // active connection - the one for which the_setup is used for 371 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 372 373 // @returns 1 if oob data is available 374 // stores oob data in provided 16 byte buffer if not null 375 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 376 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 377 378 // horizontal: initiator capabilities 379 // vertial: responder capabilities 380 static const stk_generation_method_t stk_generation_method [5] [5] = { 381 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 382 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 383 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 384 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 385 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 386 }; 387 388 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 389 #ifdef ENABLE_LE_SECURE_CONNECTIONS 390 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 391 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 392 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 393 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 394 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 395 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 396 }; 397 #endif 398 399 static void sm_run(void); 400 static void sm_done_for_handle(hci_con_handle_t con_handle); 401 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 402 static inline int sm_calc_actual_encryption_key_size(int other); 403 static int sm_validate_stk_generation_method(void); 404 static void sm_handle_encryption_result_address_resolution(void *arg); 405 static void sm_handle_encryption_result_dkg_dhk(void *arg); 406 static void sm_handle_encryption_result_dkg_irk(void *arg); 407 static void sm_handle_encryption_result_enc_a(void *arg); 408 static void sm_handle_encryption_result_enc_b(void *arg); 409 static void sm_handle_encryption_result_enc_c(void *arg); 410 static void sm_handle_encryption_result_enc_csrk(void *arg); 411 static void sm_handle_encryption_result_enc_d(void * arg); 412 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 413 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 414 #ifdef ENABLE_LE_PERIPHERAL 415 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 416 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 417 #endif 418 static void sm_handle_encryption_result_enc_stk(void *arg); 419 static void sm_handle_encryption_result_rau(void *arg); 420 static void sm_handle_random_result_ph2_tk(void * arg); 421 static void sm_handle_random_result_rau(void * arg); 422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 423 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 424 static void sm_ec_generate_new_key(void); 425 static void sm_handle_random_result_sc_get_random(void * arg); 426 static int sm_passkey_entry(stk_generation_method_t method); 427 #endif 428 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 429 430 static void log_info_hex16(const char * name, uint16_t value){ 431 log_info("%-6s 0x%04x", name, value); 432 } 433 434 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 435 // return packet[0]; 436 // } 437 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 438 return packet[1]; 439 } 440 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 441 return packet[2]; 442 } 443 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 444 return packet[3]; 445 } 446 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 447 return packet[4]; 448 } 449 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 450 return packet[5]; 451 } 452 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 453 return packet[6]; 454 } 455 456 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 457 packet[0] = code; 458 } 459 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 460 packet[1] = io_capability; 461 } 462 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 463 packet[2] = oob_data_flag; 464 } 465 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 466 packet[3] = auth_req; 467 } 468 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 469 packet[4] = max_encryption_key_size; 470 } 471 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 472 packet[5] = initiator_key_distribution; 473 } 474 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 475 packet[6] = responder_key_distribution; 476 } 477 478 // @returns 1 if all bytes are 0 479 static int sm_is_null(uint8_t * data, int size){ 480 int i; 481 for (i=0; i < size ; i++){ 482 if (data[i]) return 0; 483 } 484 return 1; 485 } 486 487 static int sm_is_null_random(uint8_t random[8]){ 488 return sm_is_null(random, 8); 489 } 490 491 static int sm_is_null_key(uint8_t * key){ 492 return sm_is_null(key, 16); 493 } 494 495 // Key utils 496 static void sm_reset_tk(void){ 497 int i; 498 for (i=0;i<16;i++){ 499 setup->sm_tk[i] = 0; 500 } 501 } 502 503 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 504 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 505 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 506 int i; 507 for (i = max_encryption_size ; i < 16 ; i++){ 508 key[15-i] = 0; 509 } 510 } 511 512 // ER / IR checks 513 static void sm_er_ir_set_default(void){ 514 int i; 515 for (i=0;i<16;i++){ 516 sm_persistent_er[i] = 0x30 + i; 517 sm_persistent_ir[i] = 0x90 + i; 518 } 519 } 520 521 static int sm_er_is_default(void){ 522 int i; 523 for (i=0;i<16;i++){ 524 if (sm_persistent_er[i] != (0x30+i)) return 0; 525 } 526 return 1; 527 } 528 529 static int sm_ir_is_default(void){ 530 int i; 531 for (i=0;i<16;i++){ 532 if (sm_persistent_ir[i] != (0x90+i)) return 0; 533 } 534 return 1; 535 } 536 537 // SMP Timeout implementation 538 539 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 540 // the Security Manager Timer shall be reset and started. 541 // 542 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 543 // 544 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 545 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 546 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 547 // established. 548 549 static void sm_timeout_handler(btstack_timer_source_t * timer){ 550 log_info("SM timeout"); 551 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 552 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 553 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 554 sm_done_for_handle(sm_conn->sm_handle); 555 556 // trigger handling of next ready connection 557 sm_run(); 558 } 559 static void sm_timeout_start(sm_connection_t * sm_conn){ 560 btstack_run_loop_remove_timer(&setup->sm_timeout); 561 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 562 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 563 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 564 btstack_run_loop_add_timer(&setup->sm_timeout); 565 } 566 static void sm_timeout_stop(void){ 567 btstack_run_loop_remove_timer(&setup->sm_timeout); 568 } 569 static void sm_timeout_reset(sm_connection_t * sm_conn){ 570 sm_timeout_stop(); 571 sm_timeout_start(sm_conn); 572 } 573 574 // end of sm timeout 575 576 // GAP Random Address updates 577 static gap_random_address_type_t gap_random_adress_type; 578 static btstack_timer_source_t gap_random_address_update_timer; 579 static uint32_t gap_random_adress_update_period; 580 581 static void gap_random_address_trigger(void){ 582 log_info("gap_random_address_trigger, state %u", rau_state); 583 if (rau_state != RAU_IDLE) return; 584 rau_state = RAU_GET_RANDOM; 585 sm_run(); 586 } 587 588 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 589 UNUSED(timer); 590 591 log_info("GAP Random Address Update due"); 592 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 593 btstack_run_loop_add_timer(&gap_random_address_update_timer); 594 gap_random_address_trigger(); 595 } 596 597 static void gap_random_address_update_start(void){ 598 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 599 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 600 btstack_run_loop_add_timer(&gap_random_address_update_timer); 601 } 602 603 static void gap_random_address_update_stop(void){ 604 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 605 } 606 607 // ah(k,r) helper 608 // r = padding || r 609 // r - 24 bit value 610 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 611 // r'= padding || r 612 memset(r_prime, 0, 16); 613 memcpy(&r_prime[13], r, 3); 614 } 615 616 // d1 helper 617 // d' = padding || r || d 618 // d,r - 16 bit values 619 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 620 // d'= padding || r || d 621 memset(d1_prime, 0, 16); 622 big_endian_store_16(d1_prime, 12, r); 623 big_endian_store_16(d1_prime, 14, d); 624 } 625 626 // dm helper 627 // r’ = padding || r 628 // r - 64 bit value 629 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 630 memset(r_prime, 0, 16); 631 memcpy(&r_prime[8], r, 8); 632 } 633 634 // calculate arguments for first AES128 operation in C1 function 635 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 636 637 // p1 = pres || preq || rat’ || iat’ 638 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 639 // cant octet of pres becomes the most significant octet of p1. 640 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 641 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 642 // p1 is 0x05000800000302070710000001010001." 643 644 sm_key_t p1; 645 reverse_56(pres, &p1[0]); 646 reverse_56(preq, &p1[7]); 647 p1[14] = rat; 648 p1[15] = iat; 649 log_info_key("p1", p1); 650 log_info_key("r", r); 651 652 // t1 = r xor p1 653 int i; 654 for (i=0;i<16;i++){ 655 t1[i] = r[i] ^ p1[i]; 656 } 657 log_info_key("t1", t1); 658 } 659 660 // calculate arguments for second AES128 operation in C1 function 661 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 662 // p2 = padding || ia || ra 663 // "The least significant octet of ra becomes the least significant octet of p2 and 664 // the most significant octet of padding becomes the most significant octet of p2. 665 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 666 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 667 668 sm_key_t p2; 669 memset(p2, 0, 16); 670 memcpy(&p2[4], ia, 6); 671 memcpy(&p2[10], ra, 6); 672 log_info_key("p2", p2); 673 674 // c1 = e(k, t2_xor_p2) 675 int i; 676 for (i=0;i<16;i++){ 677 t3[i] = t2[i] ^ p2[i]; 678 } 679 log_info_key("t3", t3); 680 } 681 682 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 683 log_info_key("r1", r1); 684 log_info_key("r2", r2); 685 memcpy(&r_prime[8], &r2[8], 8); 686 memcpy(&r_prime[0], &r1[8], 8); 687 } 688 689 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 690 UNUSED(channel); 691 692 // log event 693 hci_dump_packet(packet_type, 1, packet, size); 694 // dispatch to all event handlers 695 btstack_linked_list_iterator_t it; 696 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 697 while (btstack_linked_list_iterator_has_next(&it)){ 698 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 699 entry->callback(packet_type, 0, packet, size); 700 } 701 } 702 703 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 704 event[0] = type; 705 event[1] = event_size - 2; 706 little_endian_store_16(event, 2, con_handle); 707 event[4] = addr_type; 708 reverse_bd_addr(address, &event[5]); 709 } 710 711 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 712 uint8_t event[11]; 713 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 714 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 715 } 716 717 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 718 uint8_t event[15]; 719 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 720 little_endian_store_32(event, 11, passkey); 721 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 722 } 723 724 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 725 // fetch addr and addr type from db, only called for valid entries 726 bd_addr_t identity_address; 727 int identity_address_type; 728 le_device_db_info(index, &identity_address_type, identity_address, NULL); 729 730 uint8_t event[20]; 731 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 732 event[11] = identity_address_type; 733 reverse_bd_addr(identity_address, &event[12]); 734 little_endian_store_16(event, 18, index); 735 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 736 } 737 738 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 739 uint8_t event[12]; 740 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 741 event[11] = status; 742 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 743 } 744 745 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 746 uint8_t event[13]; 747 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 748 event[11] = status; 749 event[12] = reason; 750 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 751 } 752 753 // decide on stk generation based on 754 // - pairing request 755 // - io capabilities 756 // - OOB data availability 757 static void sm_setup_tk(void){ 758 759 // default: just works 760 setup->sm_stk_generation_method = JUST_WORKS; 761 762 #ifdef ENABLE_LE_SECURE_CONNECTIONS 763 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 764 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 765 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 766 #else 767 setup->sm_use_secure_connections = 0; 768 #endif 769 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 770 771 772 // decide if OOB will be used based on SC vs. Legacy and oob flags 773 int use_oob = 0; 774 if (setup->sm_use_secure_connections){ 775 // In LE Secure Connections pairing, the out of band method is used if at least 776 // one device has the peer device's out of band authentication data available. 777 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 778 } else { 779 // In LE legacy pairing, the out of band method is used if both the devices have 780 // the other device's out of band authentication data available. 781 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 782 } 783 if (use_oob){ 784 log_info("SM: have OOB data"); 785 log_info_key("OOB", setup->sm_tk); 786 setup->sm_stk_generation_method = OOB; 787 return; 788 } 789 790 // If both devices have not set the MITM option in the Authentication Requirements 791 // Flags, then the IO capabilities shall be ignored and the Just Works association 792 // model shall be used. 793 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 794 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 795 log_info("SM: MITM not required by both -> JUST WORKS"); 796 return; 797 } 798 799 // Reset TK as it has been setup in sm_init_setup 800 sm_reset_tk(); 801 802 // Also use just works if unknown io capabilites 803 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 804 return; 805 } 806 807 // Otherwise the IO capabilities of the devices shall be used to determine the 808 // pairing method as defined in Table 2.4. 809 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 810 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 811 812 #ifdef ENABLE_LE_SECURE_CONNECTIONS 813 // table not define by default 814 if (setup->sm_use_secure_connections){ 815 generation_method = stk_generation_method_with_secure_connection; 816 } 817 #endif 818 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 819 820 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 821 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 822 } 823 824 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 825 int flags = 0; 826 if (key_set & SM_KEYDIST_ENC_KEY){ 827 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 828 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 829 } 830 if (key_set & SM_KEYDIST_ID_KEY){ 831 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 832 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 833 } 834 if (key_set & SM_KEYDIST_SIGN){ 835 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 836 } 837 return flags; 838 } 839 840 static void sm_setup_key_distribution(uint8_t key_set){ 841 setup->sm_key_distribution_received_set = 0; 842 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 843 setup->sm_key_distribution_sent_set = 0; 844 #ifdef ENABLE_LE_SIGNED_WRITE 845 setup->sm_le_device_index = -1; 846 #endif 847 } 848 849 // CSRK Key Lookup 850 851 852 static int sm_address_resolution_idle(void){ 853 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 854 } 855 856 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 857 memcpy(sm_address_resolution_address, addr, 6); 858 sm_address_resolution_addr_type = addr_type; 859 sm_address_resolution_test = 0; 860 sm_address_resolution_mode = mode; 861 sm_address_resolution_context = context; 862 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 863 } 864 865 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 866 // check if already in list 867 btstack_linked_list_iterator_t it; 868 sm_lookup_entry_t * entry; 869 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 870 while(btstack_linked_list_iterator_has_next(&it)){ 871 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 872 if (entry->address_type != address_type) continue; 873 if (memcmp(entry->address, address, 6)) continue; 874 // already in list 875 return BTSTACK_BUSY; 876 } 877 entry = btstack_memory_sm_lookup_entry_get(); 878 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 879 entry->address_type = (bd_addr_type_t) address_type; 880 memcpy(entry->address, address, 6); 881 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 882 sm_run(); 883 return 0; 884 } 885 886 // CMAC calculation using AES Engineq 887 #ifdef USE_CMAC_ENGINE 888 889 static void sm_cmac_done_trampoline(void * arg){ 890 UNUSED(arg); 891 sm_cmac_active = 0; 892 (*sm_cmac_done_callback)(sm_cmac_hash); 893 sm_run(); 894 } 895 896 int sm_cmac_ready(void){ 897 return sm_cmac_active == 0; 898 } 899 #endif 900 901 #ifdef ENABLE_LE_SECURE_CONNECTIONS 902 // generic cmac calculation 903 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 904 sm_cmac_active = 1; 905 sm_cmac_done_callback = done_callback; 906 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 907 } 908 #endif 909 910 // cmac for ATT Message signing 911 #ifdef ENABLE_LE_SIGNED_WRITE 912 913 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 914 sm_cmac_active = 1; 915 sm_cmac_done_callback = done_callback; 916 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 917 } 918 919 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 920 if (offset >= sm_cmac_signed_write_message_len) { 921 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 922 return 0; 923 } 924 925 offset = sm_cmac_signed_write_message_len - 1 - offset; 926 927 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 928 if (offset < 3){ 929 return sm_cmac_signed_write_header[offset]; 930 } 931 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 932 if (offset < actual_message_len_incl_header){ 933 return sm_cmac_signed_write_message[offset - 3]; 934 } 935 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 936 } 937 938 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 939 // ATT Message Signing 940 sm_cmac_signed_write_header[0] = opcode; 941 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 942 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 943 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 944 sm_cmac_signed_write_message = message; 945 sm_cmac_signed_write_message_len = total_message_len; 946 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 947 } 948 #endif 949 950 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 951 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 952 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 953 switch (setup->sm_stk_generation_method){ 954 case PK_RESP_INPUT: 955 if (IS_RESPONDER(sm_conn->sm_role)){ 956 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 957 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 958 } else { 959 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 960 } 961 break; 962 case PK_INIT_INPUT: 963 if (IS_RESPONDER(sm_conn->sm_role)){ 964 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 965 } else { 966 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 967 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 968 } 969 break; 970 case PK_BOTH_INPUT: 971 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 972 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 973 break; 974 case NUMERIC_COMPARISON: 975 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 976 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 977 break; 978 case JUST_WORKS: 979 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 980 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 981 break; 982 case OOB: 983 // client already provided OOB data, let's skip notification. 984 break; 985 } 986 } 987 988 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 989 int recv_flags; 990 if (IS_RESPONDER(sm_conn->sm_role)){ 991 // slave / responder 992 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 993 } else { 994 // master / initiator 995 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 996 } 997 998 #ifdef ENABLE_LE_SECURE_CONNECTIONS 999 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1000 if (setup->sm_use_secure_connections){ 1001 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1002 } 1003 #endif 1004 1005 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1006 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1007 } 1008 1009 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1010 if (sm_active_connection_handle == con_handle){ 1011 sm_timeout_stop(); 1012 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1013 log_info("sm: connection 0x%x released setup context", con_handle); 1014 1015 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1016 // generate new ec key after each pairing (that used it) 1017 if (setup->sm_use_secure_connections){ 1018 sm_ec_generate_new_key(); 1019 } 1020 #endif 1021 } 1022 } 1023 1024 static int sm_key_distribution_flags_for_auth_req(void){ 1025 1026 int flags = SM_KEYDIST_ID_KEY; 1027 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1028 // encryption and signing information only if bonding requested 1029 flags |= SM_KEYDIST_ENC_KEY; 1030 #ifdef ENABLE_LE_SIGNED_WRITE 1031 flags |= SM_KEYDIST_SIGN; 1032 #endif 1033 } 1034 return flags; 1035 } 1036 1037 static void sm_reset_setup(void){ 1038 // fill in sm setup 1039 setup->sm_state_vars = 0; 1040 setup->sm_keypress_notification = 0; 1041 sm_reset_tk(); 1042 } 1043 1044 static void sm_init_setup(sm_connection_t * sm_conn){ 1045 1046 // fill in sm setup 1047 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1048 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1049 1050 // query client for Legacy Pairing OOB data 1051 setup->sm_have_oob_data = 0; 1052 if (sm_get_oob_data) { 1053 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1054 } 1055 1056 // if available and SC supported, also ask for SC OOB Data 1057 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1058 memset(setup->sm_ra, 0, 16); 1059 memset(setup->sm_rb, 0, 16); 1060 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1061 if (sm_get_sc_oob_data){ 1062 if (IS_RESPONDER(sm_conn->sm_role)){ 1063 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1064 sm_conn->sm_peer_addr_type, 1065 sm_conn->sm_peer_address, 1066 setup->sm_peer_confirm, 1067 setup->sm_ra); 1068 } else { 1069 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1070 sm_conn->sm_peer_addr_type, 1071 sm_conn->sm_peer_address, 1072 setup->sm_peer_confirm, 1073 setup->sm_rb); 1074 } 1075 } else { 1076 setup->sm_have_oob_data = 0; 1077 } 1078 } 1079 #endif 1080 1081 sm_pairing_packet_t * local_packet; 1082 if (IS_RESPONDER(sm_conn->sm_role)){ 1083 // slave 1084 local_packet = &setup->sm_s_pres; 1085 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1086 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1087 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1088 } else { 1089 // master 1090 local_packet = &setup->sm_m_preq; 1091 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1092 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1093 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1094 1095 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1096 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1097 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1098 } 1099 1100 uint8_t auth_req = sm_auth_req; 1101 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1102 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1103 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1104 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1105 } 1106 1107 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1108 1109 sm_pairing_packet_t * remote_packet; 1110 int remote_key_request; 1111 if (IS_RESPONDER(sm_conn->sm_role)){ 1112 // slave / responder 1113 remote_packet = &setup->sm_m_preq; 1114 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1115 } else { 1116 // master / initiator 1117 remote_packet = &setup->sm_s_pres; 1118 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1119 } 1120 1121 // check key size 1122 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1123 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1124 1125 // decide on STK generation method / SC 1126 sm_setup_tk(); 1127 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1128 1129 // check if STK generation method is acceptable by client 1130 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1131 1132 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1133 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1134 if (setup->sm_use_secure_connections){ 1135 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1136 } 1137 #endif 1138 1139 // identical to responder 1140 sm_setup_key_distribution(remote_key_request); 1141 1142 // JUST WORKS doens't provide authentication 1143 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1144 1145 return 0; 1146 } 1147 1148 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1149 1150 // cache and reset context 1151 int matched_device_id = sm_address_resolution_test; 1152 address_resolution_mode_t mode = sm_address_resolution_mode; 1153 void * context = sm_address_resolution_context; 1154 1155 // reset context 1156 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1157 sm_address_resolution_context = NULL; 1158 sm_address_resolution_test = -1; 1159 hci_con_handle_t con_handle = 0; 1160 1161 sm_connection_t * sm_connection; 1162 #ifdef ENABLE_LE_CENTRAL 1163 sm_key_t ltk; 1164 int have_ltk; 1165 int pairing_need; 1166 #endif 1167 switch (mode){ 1168 case ADDRESS_RESOLUTION_GENERAL: 1169 break; 1170 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1171 sm_connection = (sm_connection_t *) context; 1172 con_handle = sm_connection->sm_handle; 1173 switch (event){ 1174 case ADDRESS_RESOLUTION_SUCEEDED: 1175 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1176 sm_connection->sm_le_db_index = matched_device_id; 1177 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1178 if (sm_connection->sm_role) { 1179 // LTK request received before, IRK required -> start LTK calculation 1180 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1181 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1182 } 1183 break; 1184 } 1185 #ifdef ENABLE_LE_CENTRAL 1186 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1187 have_ltk = !sm_is_null_key(ltk); 1188 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1189 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1190 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1191 // reset requests 1192 sm_connection->sm_security_request_received = 0; 1193 sm_connection->sm_pairing_requested = 0; 1194 1195 // have ltk -> start encryption 1196 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1197 // "When a bond has been created between two devices, any reconnection should result in the local device 1198 // enabling or requesting encryption with the remote device before initiating any service request." 1199 if (have_ltk){ 1200 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1202 break; 1203 #else 1204 log_info("central: defer enabling encryption for bonded device"); 1205 #endif 1206 } 1207 // pairint_request -> send pairing request 1208 if (pairing_need){ 1209 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1210 break; 1211 } 1212 #endif 1213 break; 1214 case ADDRESS_RESOLUTION_FAILED: 1215 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1216 if (sm_connection->sm_role) { 1217 // LTK request received before, IRK required -> negative LTK reply 1218 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1219 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1220 } 1221 break; 1222 } 1223 #ifdef ENABLE_LE_CENTRAL 1224 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1225 sm_connection->sm_security_request_received = 0; 1226 sm_connection->sm_pairing_requested = 0; 1227 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1228 #endif 1229 break; 1230 } 1231 break; 1232 default: 1233 break; 1234 } 1235 1236 switch (event){ 1237 case ADDRESS_RESOLUTION_SUCEEDED: 1238 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1239 break; 1240 case ADDRESS_RESOLUTION_FAILED: 1241 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1242 break; 1243 } 1244 } 1245 1246 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1247 1248 int le_db_index = -1; 1249 1250 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1251 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1252 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1253 & SM_AUTHREQ_BONDING ) != 0; 1254 1255 if (bonding_enabed){ 1256 1257 // lookup device based on IRK 1258 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1259 int i; 1260 for (i=0; i < le_device_db_max_count(); i++){ 1261 sm_key_t irk; 1262 bd_addr_t address; 1263 int address_type = BD_ADDR_TYPE_UNKNOWN; 1264 le_device_db_info(i, &address_type, address, irk); 1265 // skip unused entries 1266 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1267 // compare IRK 1268 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1269 1270 log_info("sm: device found for IRK, updating"); 1271 le_db_index = i; 1272 break; 1273 } 1274 } else { 1275 // assert IRK is set to zero 1276 memset(setup->sm_peer_irk, 0, 16); 1277 } 1278 1279 // if not found, lookup via public address if possible 1280 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1281 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1282 int i; 1283 for (i=0; i < le_device_db_max_count(); i++){ 1284 bd_addr_t address; 1285 int address_type = BD_ADDR_TYPE_UNKNOWN; 1286 le_device_db_info(i, &address_type, address, NULL); 1287 // skip unused entries 1288 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1289 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1290 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1291 log_info("sm: device found for public address, updating"); 1292 le_db_index = i; 1293 break; 1294 } 1295 } 1296 } 1297 1298 // if not found, add to db 1299 if (le_db_index < 0) { 1300 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1301 } 1302 1303 if (le_db_index >= 0){ 1304 1305 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1306 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1307 1308 #ifdef ENABLE_LE_SIGNED_WRITE 1309 // store local CSRK 1310 setup->sm_le_device_index = le_db_index; 1311 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1312 log_info("sm: store local CSRK"); 1313 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1314 le_device_db_local_counter_set(le_db_index, 0); 1315 } 1316 1317 // store remote CSRK 1318 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1319 log_info("sm: store remote CSRK"); 1320 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1321 le_device_db_remote_counter_set(le_db_index, 0); 1322 } 1323 #endif 1324 // store encryption information for secure connections: LTK generated by ECDH 1325 if (setup->sm_use_secure_connections){ 1326 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1327 uint8_t zero_rand[8]; 1328 memset(zero_rand, 0, 8); 1329 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1330 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1331 } 1332 1333 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1334 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1335 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1336 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1337 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1338 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1339 1340 } 1341 } 1342 } else { 1343 log_info("Ignoring received keys, bonding not enabled"); 1344 } 1345 1346 // keep le_db_index 1347 sm_conn->sm_le_db_index = le_db_index; 1348 } 1349 1350 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1351 setup->sm_pairing_failed_reason = reason; 1352 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1353 } 1354 1355 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1356 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1357 } 1358 1359 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1360 1361 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1362 static int sm_passkey_used(stk_generation_method_t method); 1363 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1364 1365 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1366 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1367 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, (void *)(uintptr_t) sm_conn->sm_handle); 1368 } else { 1369 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1370 } 1371 } 1372 1373 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1374 if (IS_RESPONDER(sm_conn->sm_role)){ 1375 // Responder 1376 if (setup->sm_stk_generation_method == OOB){ 1377 // generate Nb 1378 log_info("Generate Nb"); 1379 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, (void *)(uintptr_t) sm_conn->sm_handle); 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 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1687 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1688 if (sm_conn == NULL) return; 1689 1690 log_info("dhkey"); 1691 log_info_hexdump(&setup->sm_dhkey[0], 32); 1692 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1693 // trigger next step 1694 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1695 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1696 } 1697 sm_run(); 1698 } 1699 1700 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1701 // calculate DHKCheck 1702 sm_key56_t bd_addr_master, bd_addr_slave; 1703 bd_addr_master[0] = setup->sm_m_addr_type; 1704 bd_addr_slave[0] = setup->sm_s_addr_type; 1705 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1706 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1707 uint8_t iocap_a[3]; 1708 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1709 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1710 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1711 uint8_t iocap_b[3]; 1712 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1713 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1714 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1715 if (IS_RESPONDER(sm_conn->sm_role)){ 1716 // responder 1717 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); 1718 } else { 1719 // initiator 1720 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); 1721 } 1722 } 1723 1724 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1725 // validate E = f6() 1726 sm_key56_t bd_addr_master, bd_addr_slave; 1727 bd_addr_master[0] = setup->sm_m_addr_type; 1728 bd_addr_slave[0] = setup->sm_s_addr_type; 1729 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1730 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1731 1732 uint8_t iocap_a[3]; 1733 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1734 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1735 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1736 uint8_t iocap_b[3]; 1737 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1738 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1739 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1740 if (IS_RESPONDER(sm_conn->sm_role)){ 1741 // responder 1742 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); 1743 } else { 1744 // initiator 1745 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); 1746 } 1747 } 1748 1749 1750 // 1751 // Link Key Conversion Function h6 1752 // 1753 // h6(W, keyID) = AES-CMACW(keyID) 1754 // - W is 128 bits 1755 // - keyID is 32 bits 1756 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1757 const uint16_t message_len = 4; 1758 sm_cmac_connection = sm_conn; 1759 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1760 log_info("h6 key"); 1761 log_info_hexdump(w, 16); 1762 log_info("h6 message"); 1763 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1764 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1765 } 1766 1767 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1768 // Errata Service Release to the Bluetooth Specification: ESR09 1769 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1770 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1771 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1772 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1773 } 1774 1775 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1776 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1777 } 1778 1779 #endif 1780 1781 // key management legacy connections: 1782 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1783 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1784 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1785 // - responder reconnects: responder uses LTK receveived from master 1786 1787 // key management secure connections: 1788 // - both devices store same LTK from ECDH key exchange. 1789 1790 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1791 static void sm_load_security_info(sm_connection_t * sm_connection){ 1792 int encryption_key_size; 1793 int authenticated; 1794 int authorized; 1795 int secure_connection; 1796 1797 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1798 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1799 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1800 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); 1801 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1802 sm_connection->sm_connection_authenticated = authenticated; 1803 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1804 sm_connection->sm_connection_sc = secure_connection; 1805 } 1806 #endif 1807 1808 #ifdef ENABLE_LE_PERIPHERAL 1809 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1810 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1811 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1812 // re-establish used key encryption size 1813 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1814 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1815 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1816 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1817 // Legacy paring -> not SC 1818 sm_connection->sm_connection_sc = 0; 1819 log_info("sm: received ltk request with key size %u, authenticated %u", 1820 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1821 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1822 sm_run(); 1823 } 1824 #endif 1825 1826 static void sm_run(void){ 1827 1828 btstack_linked_list_iterator_t it; 1829 1830 // assert that stack has already bootet 1831 if (hci_get_state() != HCI_STATE_WORKING) return; 1832 1833 // assert that we can send at least commands 1834 if (!hci_can_send_command_packet_now()) return; 1835 1836 // pause until IR/ER are ready 1837 if (sm_persistent_keys_random_active) return; 1838 1839 // 1840 // non-connection related behaviour 1841 // 1842 1843 // distributed key generation 1844 switch (dkg_state){ 1845 case DKG_CALC_IRK: 1846 // already busy? 1847 if (sm_aes128_state == SM_AES128_IDLE) { 1848 log_info("DKG_CALC_IRK started"); 1849 // IRK = d1(IR, 1, 0) 1850 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1851 sm_aes128_state = SM_AES128_ACTIVE; 1852 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1853 return; 1854 } 1855 break; 1856 case DKG_CALC_DHK: 1857 // already busy? 1858 if (sm_aes128_state == SM_AES128_IDLE) { 1859 log_info("DKG_CALC_DHK started"); 1860 // DHK = d1(IR, 3, 0) 1861 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1862 sm_aes128_state = SM_AES128_ACTIVE; 1863 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1864 return; 1865 } 1866 break; 1867 default: 1868 break; 1869 } 1870 1871 // random address updates 1872 switch (rau_state){ 1873 case RAU_GET_RANDOM: 1874 rau_state = RAU_W4_RANDOM; 1875 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1876 return; 1877 case RAU_GET_ENC: 1878 // already busy? 1879 if (sm_aes128_state == SM_AES128_IDLE) { 1880 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1881 sm_aes128_state = SM_AES128_ACTIVE; 1882 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1883 return; 1884 } 1885 break; 1886 case RAU_SET_ADDRESS: 1887 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1888 rau_state = RAU_IDLE; 1889 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1890 return; 1891 default: 1892 break; 1893 } 1894 1895 // CSRK Lookup 1896 // -- if csrk lookup ready, find connection that require csrk lookup 1897 if (sm_address_resolution_idle()){ 1898 hci_connections_get_iterator(&it); 1899 while(btstack_linked_list_iterator_has_next(&it)){ 1900 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1901 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1902 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1903 // and start lookup 1904 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); 1905 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1906 break; 1907 } 1908 } 1909 } 1910 1911 // -- if csrk lookup ready, resolved addresses for received addresses 1912 if (sm_address_resolution_idle()) { 1913 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1914 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1915 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1916 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1917 btstack_memory_sm_lookup_entry_free(entry); 1918 } 1919 } 1920 1921 // -- Continue with CSRK device lookup by public or resolvable private address 1922 if (!sm_address_resolution_idle()){ 1923 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1924 while (sm_address_resolution_test < le_device_db_max_count()){ 1925 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1926 bd_addr_t addr; 1927 sm_key_t irk; 1928 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1929 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1930 1931 // skip unused entries 1932 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1933 sm_address_resolution_test++; 1934 continue; 1935 } 1936 1937 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1938 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1939 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1940 break; 1941 } 1942 1943 // if connection type is public, it must be a different one 1944 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1945 sm_address_resolution_test++; 1946 continue; 1947 } 1948 1949 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1950 1951 log_info("LE Device Lookup: calculate AH"); 1952 log_info_key("IRK", irk); 1953 1954 memcpy(sm_aes128_key, irk, 16); 1955 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1956 sm_address_resolution_ah_calculation_active = 1; 1957 sm_aes128_state = SM_AES128_ACTIVE; 1958 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1959 return; 1960 } 1961 1962 if (sm_address_resolution_test >= le_device_db_max_count()){ 1963 log_info("LE Device Lookup: not found"); 1964 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1965 } 1966 } 1967 1968 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1969 switch (sm_sc_oob_state){ 1970 case SM_SC_OOB_W2_CALC_CONFIRM: 1971 if (!sm_cmac_ready()) break; 1972 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 1973 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 1974 return; 1975 default: 1976 break; 1977 } 1978 #endif 1979 1980 // assert that we can send at least commands - cmd might have been sent by crypto engine 1981 if (!hci_can_send_command_packet_now()) return; 1982 1983 // handle basic actions that don't requires the full context 1984 hci_connections_get_iterator(&it); 1985 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 1986 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1987 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1988 switch(sm_connection->sm_engine_state){ 1989 // responder side 1990 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1991 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1992 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1993 return; 1994 1995 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1996 case SM_SC_RECEIVED_LTK_REQUEST: 1997 switch (sm_connection->sm_irk_lookup_state){ 1998 case IRK_LOOKUP_FAILED: 1999 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2000 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2001 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2002 return; 2003 default: 2004 break; 2005 } 2006 break; 2007 #endif 2008 default: 2009 break; 2010 } 2011 } 2012 2013 // 2014 // active connection handling 2015 // -- use loop to handle next connection if lock on setup context is released 2016 2017 while (1) { 2018 2019 // Find connections that requires setup context and make active if no other is locked 2020 hci_connections_get_iterator(&it); 2021 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2022 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2023 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2024 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2025 int done = 1; 2026 int err; 2027 UNUSED(err); 2028 2029 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2030 // assert ec key is ready 2031 if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED 2032 || sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST){ 2033 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2034 sm_ec_generate_new_key(); 2035 } 2036 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2037 continue; 2038 } 2039 } 2040 #endif 2041 2042 switch (sm_connection->sm_engine_state) { 2043 #ifdef ENABLE_LE_PERIPHERAL 2044 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2045 // send packet if possible, 2046 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2047 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2048 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2049 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2050 } else { 2051 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2052 } 2053 // don't lock sxetup context yet 2054 done = 0; 2055 break; 2056 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2057 sm_reset_setup(); 2058 sm_init_setup(sm_connection); 2059 // recover pairing request 2060 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2061 err = sm_stk_generation_init(sm_connection); 2062 2063 #ifdef ENABLE_TESTING_SUPPORT 2064 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2065 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2066 err = test_pairing_failure; 2067 } 2068 #endif 2069 if (err){ 2070 setup->sm_pairing_failed_reason = err; 2071 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2072 break; 2073 } 2074 sm_timeout_start(sm_connection); 2075 // generate random number first, if we need to show passkey 2076 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2077 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_connection->sm_handle); 2078 break; 2079 } 2080 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2081 break; 2082 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2083 sm_reset_setup(); 2084 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2085 break; 2086 2087 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2088 case SM_SC_RECEIVED_LTK_REQUEST: 2089 switch (sm_connection->sm_irk_lookup_state){ 2090 case IRK_LOOKUP_SUCCEEDED: 2091 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2092 // start using context by loading security info 2093 sm_reset_setup(); 2094 sm_load_security_info(sm_connection); 2095 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2096 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2097 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2098 break; 2099 } 2100 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2101 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2102 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2103 // don't lock setup context yet 2104 return; 2105 default: 2106 // just wait until IRK lookup is completed 2107 // don't lock setup context yet 2108 done = 0; 2109 break; 2110 } 2111 break; 2112 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2113 #endif /* ENABLE_LE_PERIPHERAL */ 2114 2115 #ifdef ENABLE_LE_CENTRAL 2116 case SM_INITIATOR_PH0_HAS_LTK: 2117 sm_reset_setup(); 2118 sm_load_security_info(sm_connection); 2119 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2120 break; 2121 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2122 sm_reset_setup(); 2123 sm_init_setup(sm_connection); 2124 sm_timeout_start(sm_connection); 2125 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2126 break; 2127 #endif 2128 2129 default: 2130 done = 0; 2131 break; 2132 } 2133 if (done){ 2134 sm_active_connection_handle = sm_connection->sm_handle; 2135 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); 2136 } 2137 } 2138 2139 // 2140 // active connection handling 2141 // 2142 2143 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2144 2145 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2146 if (!connection) { 2147 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2148 return; 2149 } 2150 2151 // assert that we could send a SM PDU - not needed for all of the following 2152 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2153 log_info("cannot send now, requesting can send now event"); 2154 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2155 return; 2156 } 2157 2158 // send keypress notifications 2159 if (setup->sm_keypress_notification){ 2160 int i; 2161 uint8_t flags = setup->sm_keypress_notification & 0x1f; 2162 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2163 uint8_t action = 0; 2164 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2165 if (flags & (1<<i)){ 2166 int clear_flag = 1; 2167 switch (i){ 2168 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2169 case SM_KEYPRESS_PASSKEY_CLEARED: 2170 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2171 default: 2172 break; 2173 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2174 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2175 num_actions--; 2176 clear_flag = num_actions == 0; 2177 break; 2178 } 2179 if (clear_flag){ 2180 flags &= ~(1<<i); 2181 } 2182 action = i; 2183 break; 2184 } 2185 } 2186 setup->sm_keypress_notification = (num_actions << 5) | flags; 2187 2188 // send keypress notification 2189 uint8_t buffer[2]; 2190 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2191 buffer[1] = action; 2192 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2193 2194 // try 2195 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2196 return; 2197 } 2198 2199 int key_distribution_flags; 2200 UNUSED(key_distribution_flags); 2201 2202 log_info("sm_run: state %u", connection->sm_engine_state); 2203 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2204 log_info("sm_run // cannot send"); 2205 } 2206 switch (connection->sm_engine_state){ 2207 2208 // general 2209 case SM_GENERAL_SEND_PAIRING_FAILED: { 2210 uint8_t buffer[2]; 2211 buffer[0] = SM_CODE_PAIRING_FAILED; 2212 buffer[1] = setup->sm_pairing_failed_reason; 2213 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2214 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2215 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2216 sm_done_for_handle(connection->sm_handle); 2217 break; 2218 } 2219 2220 // responding state 2221 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2222 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2223 if (!sm_cmac_ready()) break; 2224 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2225 sm_sc_calculate_local_confirm(connection); 2226 break; 2227 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2228 if (!sm_cmac_ready()) break; 2229 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2230 sm_sc_calculate_remote_confirm(connection); 2231 break; 2232 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2233 if (!sm_cmac_ready()) break; 2234 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2235 sm_sc_calculate_f6_for_dhkey_check(connection); 2236 break; 2237 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2238 if (!sm_cmac_ready()) break; 2239 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2240 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2241 break; 2242 case SM_SC_W2_CALCULATE_F5_SALT: 2243 if (!sm_cmac_ready()) break; 2244 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2245 f5_calculate_salt(connection); 2246 break; 2247 case SM_SC_W2_CALCULATE_F5_MACKEY: 2248 if (!sm_cmac_ready()) break; 2249 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2250 f5_calculate_mackey(connection); 2251 break; 2252 case SM_SC_W2_CALCULATE_F5_LTK: 2253 if (!sm_cmac_ready()) break; 2254 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2255 f5_calculate_ltk(connection); 2256 break; 2257 case SM_SC_W2_CALCULATE_G2: 2258 if (!sm_cmac_ready()) break; 2259 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2260 g2_calculate(connection); 2261 break; 2262 case SM_SC_W2_CALCULATE_H6_ILK: 2263 if (!sm_cmac_ready()) break; 2264 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2265 h6_calculate_ilk(connection); 2266 break; 2267 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2268 if (!sm_cmac_ready()) break; 2269 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2270 h6_calculate_br_edr_link_key(connection); 2271 break; 2272 #endif 2273 2274 #ifdef ENABLE_LE_CENTRAL 2275 // initiator side 2276 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2277 sm_key_t peer_ltk_flipped; 2278 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2279 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2280 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2281 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2282 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2283 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2284 return; 2285 } 2286 2287 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2288 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2289 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2290 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2291 sm_timeout_reset(connection); 2292 break; 2293 #endif 2294 2295 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2296 2297 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2298 int trigger_user_response = 0; 2299 2300 uint8_t buffer[65]; 2301 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2302 // 2303 reverse_256(&ec_q[0], &buffer[1]); 2304 reverse_256(&ec_q[32], &buffer[33]); 2305 2306 #ifdef ENABLE_TESTING_SUPPORT 2307 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2308 log_info("testing_support: invalidating public key"); 2309 // flip single bit of public key coordinate 2310 buffer[1] ^= 1; 2311 } 2312 #endif 2313 2314 // stk generation method 2315 // passkey entry: notify app to show passkey or to request passkey 2316 switch (setup->sm_stk_generation_method){ 2317 case JUST_WORKS: 2318 case NUMERIC_COMPARISON: 2319 if (IS_RESPONDER(connection->sm_role)){ 2320 // responder 2321 sm_sc_start_calculating_local_confirm(connection); 2322 } else { 2323 // initiator 2324 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2325 } 2326 break; 2327 case PK_INIT_INPUT: 2328 case PK_RESP_INPUT: 2329 case PK_BOTH_INPUT: 2330 // use random TK for display 2331 memcpy(setup->sm_ra, setup->sm_tk, 16); 2332 memcpy(setup->sm_rb, setup->sm_tk, 16); 2333 setup->sm_passkey_bit = 0; 2334 2335 if (IS_RESPONDER(connection->sm_role)){ 2336 // responder 2337 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2338 } else { 2339 // initiator 2340 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2341 } 2342 trigger_user_response = 1; 2343 break; 2344 case OOB: 2345 if (IS_RESPONDER(connection->sm_role)){ 2346 // responder 2347 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2348 } else { 2349 // initiator 2350 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2351 } 2352 break; 2353 } 2354 2355 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2356 sm_timeout_reset(connection); 2357 2358 // trigger user response after sending pdu 2359 if (trigger_user_response){ 2360 sm_trigger_user_response(connection); 2361 } 2362 break; 2363 } 2364 case SM_SC_SEND_CONFIRMATION: { 2365 uint8_t buffer[17]; 2366 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2367 reverse_128(setup->sm_local_confirm, &buffer[1]); 2368 if (IS_RESPONDER(connection->sm_role)){ 2369 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2370 } else { 2371 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2372 } 2373 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2374 sm_timeout_reset(connection); 2375 break; 2376 } 2377 case SM_SC_SEND_PAIRING_RANDOM: { 2378 uint8_t buffer[17]; 2379 buffer[0] = SM_CODE_PAIRING_RANDOM; 2380 reverse_128(setup->sm_local_nonce, &buffer[1]); 2381 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2382 if (sm_passkey_entry(setup->sm_stk_generation_method) && setup->sm_passkey_bit < 20){ 2383 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2384 if (IS_RESPONDER(connection->sm_role)){ 2385 // responder 2386 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2387 } else { 2388 // initiator 2389 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2390 } 2391 } else { 2392 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2393 if (IS_RESPONDER(connection->sm_role)){ 2394 // responder 2395 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2396 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2397 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2398 } else { 2399 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2400 sm_sc_prepare_dhkey_check(connection); 2401 } 2402 } else { 2403 // initiator 2404 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2405 } 2406 } 2407 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2408 sm_timeout_reset(connection); 2409 break; 2410 } 2411 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2412 uint8_t buffer[17]; 2413 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2414 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2415 2416 if (IS_RESPONDER(connection->sm_role)){ 2417 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2418 } else { 2419 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2420 } 2421 2422 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2423 sm_timeout_reset(connection); 2424 break; 2425 } 2426 2427 #endif 2428 2429 #ifdef ENABLE_LE_PERIPHERAL 2430 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2431 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2432 2433 // start with initiator key dist flags 2434 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2435 2436 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2437 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2438 if (setup->sm_use_secure_connections){ 2439 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2440 } 2441 #endif 2442 // setup in response 2443 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); 2444 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); 2445 2446 // update key distribution after ENC was dropped 2447 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2448 2449 if (setup->sm_use_secure_connections){ 2450 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2451 } else { 2452 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2453 } 2454 2455 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2456 sm_timeout_reset(connection); 2457 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2458 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2459 sm_trigger_user_response(connection); 2460 } 2461 return; 2462 #endif 2463 2464 case SM_PH2_SEND_PAIRING_RANDOM: { 2465 uint8_t buffer[17]; 2466 buffer[0] = SM_CODE_PAIRING_RANDOM; 2467 reverse_128(setup->sm_local_random, &buffer[1]); 2468 if (IS_RESPONDER(connection->sm_role)){ 2469 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2470 } else { 2471 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2472 } 2473 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2474 sm_timeout_reset(connection); 2475 break; 2476 } 2477 2478 case SM_PH2_C1_GET_ENC_A: 2479 // already busy? 2480 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2481 // calculate confirm using aes128 engine - step 1 2482 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); 2483 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2484 sm_aes128_state = SM_AES128_ACTIVE; 2485 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, (void *)(uintptr_t) connection->sm_handle); 2486 break; 2487 2488 case SM_PH2_C1_GET_ENC_C: 2489 // already busy? 2490 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2491 // calculate m_confirm using aes128 engine - step 1 2492 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); 2493 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2494 sm_aes128_state = SM_AES128_ACTIVE; 2495 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, (void *)(uintptr_t) connection->sm_handle); 2496 break; 2497 2498 case SM_PH2_CALC_STK: 2499 // already busy? 2500 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2501 // calculate STK 2502 if (IS_RESPONDER(connection->sm_role)){ 2503 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2504 } else { 2505 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2506 } 2507 connection->sm_engine_state = SM_PH2_W4_STK; 2508 sm_aes128_state = SM_AES128_ACTIVE; 2509 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2510 break; 2511 2512 case SM_PH3_Y_GET_ENC: 2513 // already busy? 2514 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2515 // PH3B2 - calculate Y from - enc 2516 // Y = dm(DHK, Rand) 2517 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2518 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2519 sm_aes128_state = SM_AES128_ACTIVE; 2520 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, (void *)(uintptr_t) connection->sm_handle); 2521 break; 2522 2523 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2524 uint8_t buffer[17]; 2525 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2526 reverse_128(setup->sm_local_confirm, &buffer[1]); 2527 if (IS_RESPONDER(connection->sm_role)){ 2528 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2529 } else { 2530 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2531 } 2532 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2533 sm_timeout_reset(connection); 2534 return; 2535 } 2536 #ifdef ENABLE_LE_PERIPHERAL 2537 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2538 sm_key_t stk_flipped; 2539 reverse_128(setup->sm_ltk, stk_flipped); 2540 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2541 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2542 return; 2543 } 2544 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2545 sm_key_t ltk_flipped; 2546 reverse_128(setup->sm_ltk, ltk_flipped); 2547 connection->sm_engine_state = SM_RESPONDER_IDLE; 2548 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2549 sm_done_for_handle(connection->sm_handle); 2550 return; 2551 } 2552 case SM_RESPONDER_PH4_Y_GET_ENC: 2553 // already busy? 2554 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2555 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2556 // Y = dm(DHK, Rand) 2557 sm_dm_r_prime(setup->sm_local_rand, sm_aes128_plaintext); 2558 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2559 sm_aes128_state = SM_AES128_ACTIVE; 2560 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, (void *)(uintptr_t) connection->sm_handle); 2561 return; 2562 #endif 2563 #ifdef ENABLE_LE_CENTRAL 2564 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2565 sm_key_t stk_flipped; 2566 reverse_128(setup->sm_ltk, stk_flipped); 2567 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2568 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2569 return; 2570 } 2571 #endif 2572 2573 case SM_PH3_DISTRIBUTE_KEYS: 2574 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2575 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2576 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2577 uint8_t buffer[17]; 2578 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2579 reverse_128(setup->sm_ltk, &buffer[1]); 2580 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2581 sm_timeout_reset(connection); 2582 return; 2583 } 2584 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2585 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2586 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2587 uint8_t buffer[11]; 2588 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2589 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2590 reverse_64(setup->sm_local_rand, &buffer[3]); 2591 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2592 sm_timeout_reset(connection); 2593 return; 2594 } 2595 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2596 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2597 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2598 uint8_t buffer[17]; 2599 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2600 reverse_128(sm_persistent_irk, &buffer[1]); 2601 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2602 sm_timeout_reset(connection); 2603 return; 2604 } 2605 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2606 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2607 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2608 bd_addr_t local_address; 2609 uint8_t buffer[8]; 2610 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2611 switch (gap_random_address_get_mode()){ 2612 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2613 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2614 // public or static random 2615 gap_le_get_own_address(&buffer[1], local_address); 2616 break; 2617 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2618 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2619 // fallback to public 2620 gap_local_bd_addr(local_address); 2621 buffer[1] = 0; 2622 break; 2623 } 2624 reverse_bd_addr(local_address, &buffer[2]); 2625 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2626 sm_timeout_reset(connection); 2627 return; 2628 } 2629 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2630 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2631 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2632 2633 #ifdef ENABLE_LE_SIGNED_WRITE 2634 // hack to reproduce test runs 2635 if (test_use_fixed_local_csrk){ 2636 memset(setup->sm_local_csrk, 0xcc, 16); 2637 } 2638 2639 // store local CSRK 2640 if (setup->sm_le_device_index >= 0){ 2641 log_info("sm: store local CSRK"); 2642 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2643 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2644 } 2645 #endif 2646 2647 uint8_t buffer[17]; 2648 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2649 reverse_128(setup->sm_local_csrk, &buffer[1]); 2650 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2651 sm_timeout_reset(connection); 2652 return; 2653 } 2654 2655 // keys are sent 2656 if (IS_RESPONDER(connection->sm_role)){ 2657 // slave -> receive master keys if any 2658 if (sm_key_distribution_all_received(connection)){ 2659 sm_key_distribution_handle_all_received(connection); 2660 connection->sm_engine_state = SM_RESPONDER_IDLE; 2661 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2662 sm_done_for_handle(connection->sm_handle); 2663 } else { 2664 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2665 } 2666 } else { 2667 // master -> all done 2668 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2669 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2670 sm_done_for_handle(connection->sm_handle); 2671 } 2672 break; 2673 2674 default: 2675 break; 2676 } 2677 2678 // check again if active connection was released 2679 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2680 } 2681 } 2682 2683 // sm_aes128_state stays active 2684 static void sm_handle_encryption_result_enc_a(void *arg){ 2685 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2686 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2687 if (connection == NULL) return; 2688 2689 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2690 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, (void *)(uintptr_t) connection->sm_handle); 2691 } 2692 2693 static void sm_handle_encryption_result_enc_b(void *arg){ 2694 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2695 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2696 if (connection == NULL) return; 2697 2698 sm_aes128_state = SM_AES128_IDLE; 2699 log_info_key("c1!", setup->sm_local_confirm); 2700 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2701 sm_run(); 2702 } 2703 2704 // sm_aes128_state stays active 2705 static void sm_handle_encryption_result_enc_c(void *arg){ 2706 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2707 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2708 if (connection == NULL) return; 2709 2710 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2711 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, (void *)(uintptr_t) connection->sm_handle); 2712 } 2713 2714 static void sm_handle_encryption_result_enc_d(void * arg){ 2715 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2716 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2717 if (connection == NULL) return; 2718 2719 sm_aes128_state = SM_AES128_IDLE; 2720 log_info_key("c1!", sm_aes128_ciphertext); 2721 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2722 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2723 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2724 sm_run(); 2725 return; 2726 } 2727 if (IS_RESPONDER(connection->sm_role)){ 2728 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2729 sm_run(); 2730 } else { 2731 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2732 sm_aes128_state = SM_AES128_ACTIVE; 2733 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2734 } 2735 } 2736 2737 static void sm_handle_encryption_result_enc_stk(void *arg){ 2738 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2739 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2740 if (connection == NULL) return; 2741 2742 sm_aes128_state = SM_AES128_IDLE; 2743 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2744 log_info_key("stk", setup->sm_ltk); 2745 if (IS_RESPONDER(connection->sm_role)){ 2746 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2747 } else { 2748 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2749 } 2750 sm_run(); 2751 } 2752 2753 // sm_aes128_state stays active 2754 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2755 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2756 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2757 if (connection == NULL) return; 2758 2759 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2760 log_info_hex16("y", setup->sm_local_y); 2761 // PH3B3 - calculate EDIV 2762 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2763 log_info_hex16("ediv", setup->sm_local_ediv); 2764 // PH3B4 - calculate LTK - enc 2765 // LTK = d1(ER, DIV, 0)) 2766 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2767 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); 2768 } 2769 2770 #ifdef ENABLE_LE_PERIPHERAL 2771 // sm_aes128_state stays active 2772 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2773 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2774 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2775 if (connection == NULL) return; 2776 2777 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2778 log_info_hex16("y", setup->sm_local_y); 2779 2780 // PH3B3 - calculate DIV 2781 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2782 log_info_hex16("ediv", setup->sm_local_ediv); 2783 // PH3B4 - calculate LTK - enc 2784 // LTK = d1(ER, DIV, 0)) 2785 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2786 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, (void *)(uintptr_t) connection->sm_handle); 2787 } 2788 #endif 2789 2790 // sm_aes128_state stays active 2791 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2792 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2793 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2794 if (connection == NULL) return; 2795 2796 log_info_key("ltk", setup->sm_ltk); 2797 // calc CSRK next 2798 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2799 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); 2800 } 2801 2802 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2803 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2804 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2805 if (connection == NULL) return; 2806 2807 sm_aes128_state = SM_AES128_IDLE; 2808 log_info_key("csrk", setup->sm_local_csrk); 2809 if (setup->sm_key_distribution_send_set){ 2810 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2811 } else { 2812 // no keys to send, just continue 2813 if (IS_RESPONDER(connection->sm_role)){ 2814 // slave -> receive master keys 2815 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2816 } else { 2817 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2818 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2819 } else { 2820 // master -> all done 2821 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2822 sm_done_for_handle(connection->sm_handle); 2823 } 2824 } 2825 } 2826 sm_run(); 2827 } 2828 2829 #ifdef ENABLE_LE_PERIPHERAL 2830 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2831 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2832 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2833 if (connection == NULL) return; 2834 2835 sm_aes128_state = SM_AES128_IDLE; 2836 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2837 log_info_key("ltk", setup->sm_ltk); 2838 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2839 sm_run(); 2840 } 2841 #endif 2842 2843 static void sm_handle_encryption_result_address_resolution(void *arg){ 2844 UNUSED(arg); 2845 sm_aes128_state = SM_AES128_IDLE; 2846 sm_address_resolution_ah_calculation_active = 0; 2847 // compare calulated address against connecting device 2848 uint8_t * hash = &sm_aes128_ciphertext[13]; 2849 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2850 log_info("LE Device Lookup: matched resolvable private address"); 2851 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2852 sm_run(); 2853 return; 2854 } 2855 // no match, try next 2856 sm_address_resolution_test++; 2857 sm_run(); 2858 } 2859 2860 static void sm_handle_encryption_result_dkg_irk(void *arg){ 2861 UNUSED(arg); 2862 sm_aes128_state = SM_AES128_IDLE; 2863 log_info_key("irk", sm_persistent_irk); 2864 dkg_state = DKG_CALC_DHK; 2865 sm_run(); 2866 } 2867 2868 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 2869 UNUSED(arg); 2870 sm_aes128_state = SM_AES128_IDLE; 2871 log_info_key("dhk", sm_persistent_dhk); 2872 dkg_state = DKG_READY; 2873 sm_run(); 2874 } 2875 2876 static void sm_handle_encryption_result_rau(void *arg){ 2877 UNUSED(arg); 2878 sm_aes128_state = SM_AES128_IDLE; 2879 memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 2880 rau_state = RAU_SET_ADDRESS; 2881 sm_run(); 2882 } 2883 2884 static void sm_handle_random_result_rau(void * arg){ 2885 UNUSED(arg); 2886 // non-resolvable vs. resolvable 2887 switch (gap_random_adress_type){ 2888 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2889 // resolvable: use random as prand and calc address hash 2890 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2891 sm_random_address[0] &= 0x3f; 2892 sm_random_address[0] |= 0x40; 2893 rau_state = RAU_GET_ENC; 2894 break; 2895 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2896 default: 2897 // "The two most significant bits of the address shall be equal to ‘0’"" 2898 sm_random_address[0] &= 0x3f; 2899 rau_state = RAU_SET_ADDRESS; 2900 break; 2901 } 2902 sm_run(); 2903 } 2904 2905 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2906 static void sm_handle_random_result_sc_get_random(void * arg){ 2907 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2908 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2909 if (connection == NULL) return; 2910 2911 // OOB 2912 if (setup->sm_stk_generation_method == OOB){ 2913 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2914 sm_run(); 2915 return; 2916 } 2917 2918 // initiator & jw/nc -> send pairing random 2919 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2920 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2921 } else { 2922 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2923 } 2924 sm_run(); 2925 } 2926 #endif 2927 2928 static void sm_handle_random_result_ph2_random(void * arg){ 2929 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2930 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2931 if (connection == NULL) return; 2932 2933 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2934 sm_run(); 2935 } 2936 2937 static void sm_handle_random_result_ph2_tk(void * arg){ 2938 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2939 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2940 if (connection == NULL) return; 2941 2942 sm_reset_tk(); 2943 uint32_t tk; 2944 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 2945 // map random to 0-999999 without speding much cycles on a modulus operation 2946 tk = little_endian_read_32(sm_random_data,0); 2947 tk = tk & 0xfffff; // 1048575 2948 if (tk >= 999999){ 2949 tk = tk - 999999; 2950 } 2951 } else { 2952 // override with pre-defined passkey 2953 tk = sm_fixed_passkey_in_display_role; 2954 } 2955 big_endian_store_32(setup->sm_tk, 12, tk); 2956 if (IS_RESPONDER(connection->sm_role)){ 2957 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2958 } else { 2959 if (setup->sm_use_secure_connections){ 2960 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2961 } else { 2962 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2963 sm_trigger_user_response(connection); 2964 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2965 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2966 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) connection->sm_handle); 2967 } 2968 } 2969 } 2970 sm_run(); 2971 } 2972 2973 static void sm_handle_random_result_ph3_div(void * arg){ 2974 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2975 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2976 if (connection == NULL) return; 2977 2978 // use 16 bit from random value as div 2979 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 2980 log_info_hex16("div", setup->sm_local_div); 2981 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2982 sm_run(); 2983 } 2984 2985 static void sm_handle_random_result_ph3_random(void * arg){ 2986 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2987 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2988 if (connection == NULL) return; 2989 2990 reverse_64(sm_random_data, setup->sm_local_rand); 2991 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2992 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2993 // no db for authenticated flag hack: store flag in bit 4 of LSB 2994 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2995 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 2996 } 2997 static void sm_validate_er_ir(void){ 2998 // warn about default ER/IR 2999 int warning = 0; 3000 if (sm_ir_is_default()){ 3001 warning = 1; 3002 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3003 } 3004 if (sm_er_is_default()){ 3005 warning = 1; 3006 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3007 } 3008 if (warning) { 3009 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3010 } 3011 } 3012 3013 static void sm_handle_random_result_ir(void *arg){ 3014 sm_persistent_keys_random_active = 0; 3015 if (arg){ 3016 // key generated, store in tlv 3017 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3018 log_info("Generated IR key. Store in TLV status: %d", status); 3019 } 3020 log_info_key("IR", sm_persistent_ir); 3021 dkg_state = DKG_CALC_IRK; 3022 sm_run(); 3023 } 3024 3025 static void sm_handle_random_result_er(void *arg){ 3026 sm_persistent_keys_random_active = 0; 3027 if (arg){ 3028 // key generated, store in tlv 3029 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3030 log_info("Generated ER key. Store in TLV status: %d", status); 3031 } 3032 log_info_key("ER", sm_persistent_er); 3033 3034 // try load ir 3035 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16); 3036 if (key_size == 16){ 3037 // ok, let's continue 3038 log_info("IR from TLV"); 3039 sm_handle_random_result_ir( NULL ); 3040 } else { 3041 // invalid, generate new random one 3042 sm_persistent_keys_random_active = 1; 3043 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3044 } 3045 } 3046 3047 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3048 3049 UNUSED(channel); // ok: there is no channel 3050 UNUSED(size); // ok: fixed format HCI events 3051 3052 sm_connection_t * sm_conn; 3053 hci_con_handle_t con_handle; 3054 3055 switch (packet_type) { 3056 3057 case HCI_EVENT_PACKET: 3058 switch (hci_event_packet_get_type(packet)) { 3059 3060 case BTSTACK_EVENT_STATE: 3061 // bt stack activated, get started 3062 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3063 log_info("HCI Working!"); 3064 3065 // setup IR/ER with TLV 3066 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3067 if (sm_tlv_impl){ 3068 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16); 3069 if (key_size == 16){ 3070 // ok, let's continue 3071 log_info("ER from TLV"); 3072 sm_handle_random_result_er( NULL ); 3073 } else { 3074 // invalid, generate random one 3075 sm_persistent_keys_random_active = 1; 3076 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3077 } 3078 } else { 3079 sm_validate_er_ir(); 3080 dkg_state = DKG_CALC_IRK; 3081 } 3082 } 3083 break; 3084 3085 case HCI_EVENT_LE_META: 3086 switch (packet[2]) { 3087 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3088 3089 log_info("sm: connected"); 3090 3091 if (packet[3]) return; // connection failed 3092 3093 con_handle = little_endian_read_16(packet, 4); 3094 sm_conn = sm_get_connection_for_handle(con_handle); 3095 if (!sm_conn) break; 3096 3097 sm_conn->sm_handle = con_handle; 3098 sm_conn->sm_role = packet[6]; 3099 sm_conn->sm_peer_addr_type = packet[7]; 3100 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3101 3102 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3103 3104 // reset security properties 3105 sm_conn->sm_connection_encrypted = 0; 3106 sm_conn->sm_connection_authenticated = 0; 3107 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3108 sm_conn->sm_le_db_index = -1; 3109 3110 // prepare CSRK lookup (does not involve setup) 3111 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3112 3113 // just connected -> everything else happens in sm_run() 3114 if (IS_RESPONDER(sm_conn->sm_role)){ 3115 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3116 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3117 if (sm_slave_request_security) { 3118 // request security if requested by app 3119 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3120 } else { 3121 // otherwise, wait for pairing request 3122 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3123 } 3124 } 3125 break; 3126 } else { 3127 // master 3128 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3129 } 3130 break; 3131 3132 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3133 con_handle = little_endian_read_16(packet, 3); 3134 sm_conn = sm_get_connection_for_handle(con_handle); 3135 if (!sm_conn) break; 3136 3137 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3138 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3139 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3140 break; 3141 } 3142 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3143 // PH2 SEND LTK as we need to exchange keys in PH3 3144 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3145 break; 3146 } 3147 3148 // store rand and ediv 3149 reverse_64(&packet[5], sm_conn->sm_local_rand); 3150 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3151 3152 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3153 // potentially stored LTK is from the master 3154 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3155 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3156 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3157 break; 3158 } 3159 // additionally check if remote is in LE Device DB if requested 3160 switch(sm_conn->sm_irk_lookup_state){ 3161 case IRK_LOOKUP_FAILED: 3162 log_info("LTK Request: device not in device db"); 3163 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3164 break; 3165 case IRK_LOOKUP_SUCCEEDED: 3166 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3167 break; 3168 default: 3169 // wait for irk look doen 3170 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3171 break; 3172 } 3173 break; 3174 } 3175 3176 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3177 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3178 #else 3179 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3180 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3181 #endif 3182 break; 3183 3184 default: 3185 break; 3186 } 3187 break; 3188 3189 case HCI_EVENT_ENCRYPTION_CHANGE: 3190 con_handle = little_endian_read_16(packet, 3); 3191 sm_conn = sm_get_connection_for_handle(con_handle); 3192 if (!sm_conn) break; 3193 3194 sm_conn->sm_connection_encrypted = packet[5]; 3195 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3196 sm_conn->sm_actual_encryption_key_size); 3197 log_info("event handler, state %u", sm_conn->sm_engine_state); 3198 3199 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3200 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3201 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3202 // notify client, if pairing was requested before 3203 if (sm_conn->sm_pairing_requested){ 3204 sm_conn->sm_pairing_requested = 0; 3205 if (sm_conn->sm_connection_encrypted){ 3206 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3207 } else { 3208 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3209 } 3210 } 3211 sm_done_for_handle(sm_conn->sm_handle); 3212 break; 3213 } 3214 3215 if (!sm_conn->sm_connection_encrypted) break; 3216 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3217 3218 // continue pairing 3219 switch (sm_conn->sm_engine_state){ 3220 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3221 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3222 sm_done_for_handle(sm_conn->sm_handle); 3223 break; 3224 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3225 if (IS_RESPONDER(sm_conn->sm_role)){ 3226 // slave 3227 if (setup->sm_use_secure_connections){ 3228 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3229 } else { 3230 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3231 } 3232 } else { 3233 // master 3234 if (sm_key_distribution_all_received(sm_conn)){ 3235 // skip receiving keys as there are none 3236 sm_key_distribution_handle_all_received(sm_conn); 3237 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3238 } else { 3239 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3240 } 3241 } 3242 break; 3243 default: 3244 break; 3245 } 3246 break; 3247 3248 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3249 con_handle = little_endian_read_16(packet, 3); 3250 sm_conn = sm_get_connection_for_handle(con_handle); 3251 if (!sm_conn) break; 3252 3253 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3254 log_info("event handler, state %u", sm_conn->sm_engine_state); 3255 // continue if part of initial pairing 3256 switch (sm_conn->sm_engine_state){ 3257 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3258 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3259 sm_done_for_handle(sm_conn->sm_handle); 3260 break; 3261 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3262 if (IS_RESPONDER(sm_conn->sm_role)){ 3263 // slave 3264 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3265 } else { 3266 // master 3267 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3268 } 3269 break; 3270 default: 3271 break; 3272 } 3273 break; 3274 3275 3276 case HCI_EVENT_DISCONNECTION_COMPLETE: 3277 con_handle = little_endian_read_16(packet, 3); 3278 sm_done_for_handle(con_handle); 3279 sm_conn = sm_get_connection_for_handle(con_handle); 3280 if (!sm_conn) break; 3281 3282 // delete stored bonding on disconnect with authentication failure in ph0 3283 if (sm_conn->sm_role == 0 3284 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3285 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3286 le_device_db_remove(sm_conn->sm_le_db_index); 3287 } 3288 3289 // pairing failed, if it was ongoing 3290 switch (sm_conn->sm_engine_state){ 3291 case SM_GENERAL_IDLE: 3292 case SM_INITIATOR_CONNECTED: 3293 case SM_RESPONDER_IDLE: 3294 break; 3295 default: 3296 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3297 break; 3298 } 3299 3300 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3301 sm_conn->sm_handle = 0; 3302 break; 3303 3304 case HCI_EVENT_COMMAND_COMPLETE: 3305 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3306 // set local addr for le device db 3307 bd_addr_t addr; 3308 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3309 le_device_db_set_local_bd_addr(addr); 3310 } 3311 break; 3312 default: 3313 break; 3314 } 3315 break; 3316 default: 3317 break; 3318 } 3319 3320 sm_run(); 3321 } 3322 3323 static inline int sm_calc_actual_encryption_key_size(int other){ 3324 if (other < sm_min_encryption_key_size) return 0; 3325 if (other < sm_max_encryption_key_size) return other; 3326 return sm_max_encryption_key_size; 3327 } 3328 3329 3330 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3331 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3332 switch (method){ 3333 case JUST_WORKS: 3334 case NUMERIC_COMPARISON: 3335 return 1; 3336 default: 3337 return 0; 3338 } 3339 } 3340 // responder 3341 3342 static int sm_passkey_used(stk_generation_method_t method){ 3343 switch (method){ 3344 case PK_RESP_INPUT: 3345 return 1; 3346 default: 3347 return 0; 3348 } 3349 } 3350 3351 static int sm_passkey_entry(stk_generation_method_t method){ 3352 switch (method){ 3353 case PK_RESP_INPUT: 3354 case PK_INIT_INPUT: 3355 case PK_BOTH_INPUT: 3356 return 1; 3357 default: 3358 return 0; 3359 } 3360 } 3361 3362 #endif 3363 3364 /** 3365 * @return ok 3366 */ 3367 static int sm_validate_stk_generation_method(void){ 3368 // check if STK generation method is acceptable by client 3369 switch (setup->sm_stk_generation_method){ 3370 case JUST_WORKS: 3371 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3372 case PK_RESP_INPUT: 3373 case PK_INIT_INPUT: 3374 case PK_BOTH_INPUT: 3375 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3376 case OOB: 3377 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3378 case NUMERIC_COMPARISON: 3379 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3380 default: 3381 return 0; 3382 } 3383 } 3384 3385 // size of complete sm_pdu used to validate input 3386 static const uint8_t sm_pdu_size[] = { 3387 0, // 0x00 invalid opcode 3388 7, // 0x01 pairing request 3389 7, // 0x02 pairing response 3390 17, // 0x03 pairing confirm 3391 17, // 0x04 pairing random 3392 2, // 0x05 pairing failed 3393 17, // 0x06 encryption information 3394 11, // 0x07 master identification 3395 17, // 0x08 identification information 3396 8, // 0x09 identify address information 3397 17, // 0x0a signing information 3398 2, // 0x0b security request 3399 65, // 0x0c pairing public key 3400 17, // 0x0d pairing dhk check 3401 2, // 0x0e keypress notification 3402 }; 3403 3404 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3405 3406 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3407 sm_run(); 3408 } 3409 3410 if (packet_type != SM_DATA_PACKET) return; 3411 if (size == 0) return; 3412 3413 uint8_t sm_pdu_code = packet[0]; 3414 3415 // validate pdu size 3416 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3417 if (sm_pdu_size[sm_pdu_code] != size) return; 3418 3419 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3420 if (!sm_conn) return; 3421 3422 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3423 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3424 sm_done_for_handle(con_handle); 3425 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3426 return; 3427 } 3428 3429 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3430 3431 int err; 3432 UNUSED(err); 3433 3434 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3435 uint8_t buffer[5]; 3436 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3437 buffer[1] = 3; 3438 little_endian_store_16(buffer, 2, con_handle); 3439 buffer[4] = packet[1]; 3440 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3441 return; 3442 } 3443 3444 switch (sm_conn->sm_engine_state){ 3445 3446 // a sm timeout requries a new physical connection 3447 case SM_GENERAL_TIMEOUT: 3448 return; 3449 3450 #ifdef ENABLE_LE_CENTRAL 3451 3452 // Initiator 3453 case SM_INITIATOR_CONNECTED: 3454 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3455 sm_pdu_received_in_wrong_state(sm_conn); 3456 break; 3457 } 3458 3459 // IRK complete? 3460 int have_ltk; 3461 uint8_t ltk[16]; 3462 switch (sm_conn->sm_irk_lookup_state){ 3463 case IRK_LOOKUP_FAILED: 3464 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3465 break; 3466 case IRK_LOOKUP_SUCCEEDED: 3467 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3468 have_ltk = !sm_is_null_key(ltk); 3469 log_info("central: security request - have_ltk %u", have_ltk); 3470 if (have_ltk){ 3471 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3472 } else { 3473 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3474 } 3475 break; 3476 default: 3477 break; 3478 } 3479 3480 // otherwise, store security request 3481 sm_conn->sm_security_request_received = 1; 3482 break; 3483 3484 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3485 // Core 5, Vol 3, Part H, 2.4.6: 3486 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3487 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3488 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3489 log_info("Ignoring Security Request"); 3490 break; 3491 } 3492 3493 // all other pdus are incorrect 3494 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3495 sm_pdu_received_in_wrong_state(sm_conn); 3496 break; 3497 } 3498 3499 // store pairing request 3500 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3501 err = sm_stk_generation_init(sm_conn); 3502 3503 #ifdef ENABLE_TESTING_SUPPORT 3504 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3505 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3506 err = test_pairing_failure; 3507 } 3508 #endif 3509 3510 if (err){ 3511 setup->sm_pairing_failed_reason = err; 3512 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3513 break; 3514 } 3515 3516 // generate random number first, if we need to show passkey 3517 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3518 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_conn->sm_handle); 3519 break; 3520 } 3521 3522 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3523 if (setup->sm_use_secure_connections){ 3524 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3525 if (setup->sm_stk_generation_method == JUST_WORKS){ 3526 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3527 sm_trigger_user_response(sm_conn); 3528 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3529 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3530 } 3531 } else { 3532 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3533 } 3534 break; 3535 } 3536 #endif 3537 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3538 sm_trigger_user_response(sm_conn); 3539 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3540 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3541 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3542 } 3543 break; 3544 3545 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3546 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3547 sm_pdu_received_in_wrong_state(sm_conn); 3548 break; 3549 } 3550 3551 // store s_confirm 3552 reverse_128(&packet[1], setup->sm_peer_confirm); 3553 3554 #ifdef ENABLE_TESTING_SUPPORT 3555 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3556 log_info("testing_support: reset confirm value"); 3557 memset(setup->sm_peer_confirm, 0, 16); 3558 } 3559 #endif 3560 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3561 break; 3562 3563 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3564 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3565 sm_pdu_received_in_wrong_state(sm_conn); 3566 break;; 3567 } 3568 3569 // received random value 3570 reverse_128(&packet[1], setup->sm_peer_random); 3571 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3572 break; 3573 #endif 3574 3575 #ifdef ENABLE_LE_PERIPHERAL 3576 // Responder 3577 case SM_RESPONDER_IDLE: 3578 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3579 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3580 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3581 sm_pdu_received_in_wrong_state(sm_conn); 3582 break;; 3583 } 3584 3585 // store pairing request 3586 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3587 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3588 break; 3589 #endif 3590 3591 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3592 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3593 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3594 sm_pdu_received_in_wrong_state(sm_conn); 3595 break; 3596 } 3597 3598 // store public key for DH Key calculation 3599 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3600 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3601 3602 // validate public key 3603 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3604 if (err){ 3605 log_error("sm: peer public key invalid %x", err); 3606 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3607 break; 3608 } 3609 3610 // start calculating dhkey 3611 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, (void*)(uintptr_t) sm_conn->sm_handle); 3612 3613 3614 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3615 if (IS_RESPONDER(sm_conn->sm_role)){ 3616 // responder 3617 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3618 } else { 3619 // initiator 3620 // stk generation method 3621 // passkey entry: notify app to show passkey or to request passkey 3622 switch (setup->sm_stk_generation_method){ 3623 case JUST_WORKS: 3624 case NUMERIC_COMPARISON: 3625 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3626 break; 3627 case PK_RESP_INPUT: 3628 sm_sc_start_calculating_local_confirm(sm_conn); 3629 break; 3630 case PK_INIT_INPUT: 3631 case PK_BOTH_INPUT: 3632 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3633 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3634 break; 3635 } 3636 sm_sc_start_calculating_local_confirm(sm_conn); 3637 break; 3638 case OOB: 3639 // generate Nx 3640 log_info("Generate Na"); 3641 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, (void*)(uintptr_t) sm_conn->sm_handle); 3642 break; 3643 } 3644 } 3645 break; 3646 3647 case SM_SC_W4_CONFIRMATION: 3648 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3649 sm_pdu_received_in_wrong_state(sm_conn); 3650 break; 3651 } 3652 // received confirm value 3653 reverse_128(&packet[1], setup->sm_peer_confirm); 3654 3655 #ifdef ENABLE_TESTING_SUPPORT 3656 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3657 log_info("testing_support: reset confirm value"); 3658 memset(setup->sm_peer_confirm, 0, 16); 3659 } 3660 #endif 3661 if (IS_RESPONDER(sm_conn->sm_role)){ 3662 // responder 3663 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3664 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3665 // still waiting for passkey 3666 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3667 break; 3668 } 3669 } 3670 sm_sc_start_calculating_local_confirm(sm_conn); 3671 } else { 3672 // initiator 3673 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3674 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_get_random, (void*)(uintptr_t) sm_conn->sm_handle); 3675 } else { 3676 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3677 } 3678 } 3679 break; 3680 3681 case SM_SC_W4_PAIRING_RANDOM: 3682 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3683 sm_pdu_received_in_wrong_state(sm_conn); 3684 break; 3685 } 3686 3687 // received random value 3688 reverse_128(&packet[1], setup->sm_peer_nonce); 3689 3690 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3691 // only check for JUST WORK/NC in initiator role OR passkey entry 3692 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3693 || (sm_passkey_used(setup->sm_stk_generation_method)) ) { 3694 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3695 break; 3696 } 3697 3698 // OOB 3699 if (setup->sm_stk_generation_method == OOB){ 3700 3701 // setup local random, set to zero if remote did not receive our data 3702 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3703 if (IS_RESPONDER(sm_conn->sm_role)){ 3704 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0){ 3705 log_info("Reset rb as A does not have OOB data"); 3706 memset(setup->sm_rb, 0, 16); 3707 } else { 3708 memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3709 log_info("Use stored rb"); 3710 log_info_hexdump(setup->sm_rb, 16); 3711 } 3712 } else { 3713 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0){ 3714 log_info("Reset ra as B does not have OOB data"); 3715 memset(setup->sm_ra, 0, 16); 3716 } else { 3717 memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3718 log_info("Use stored ra"); 3719 log_info_hexdump(setup->sm_ra, 16); 3720 } 3721 } 3722 3723 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3724 if (setup->sm_have_oob_data){ 3725 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3726 break; 3727 } 3728 } 3729 3730 // TODO: we only get here for Responder role with JW/NC 3731 sm_sc_state_after_receiving_random(sm_conn); 3732 break; 3733 3734 case SM_SC_W2_CALCULATE_G2: 3735 case SM_SC_W4_CALCULATE_G2: 3736 case SM_SC_W4_CALCULATE_DHKEY: 3737 case SM_SC_W2_CALCULATE_F5_SALT: 3738 case SM_SC_W4_CALCULATE_F5_SALT: 3739 case SM_SC_W2_CALCULATE_F5_MACKEY: 3740 case SM_SC_W4_CALCULATE_F5_MACKEY: 3741 case SM_SC_W2_CALCULATE_F5_LTK: 3742 case SM_SC_W4_CALCULATE_F5_LTK: 3743 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3744 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3745 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3746 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3747 sm_pdu_received_in_wrong_state(sm_conn); 3748 break; 3749 } 3750 // store DHKey Check 3751 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3752 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3753 3754 // have we been only waiting for dhkey check command? 3755 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3756 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3757 } 3758 break; 3759 #endif 3760 3761 #ifdef ENABLE_LE_PERIPHERAL 3762 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3763 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3764 sm_pdu_received_in_wrong_state(sm_conn); 3765 break; 3766 } 3767 3768 // received confirm value 3769 reverse_128(&packet[1], setup->sm_peer_confirm); 3770 3771 #ifdef ENABLE_TESTING_SUPPORT 3772 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3773 log_info("testing_support: reset confirm value"); 3774 memset(setup->sm_peer_confirm, 0, 16); 3775 } 3776 #endif 3777 // notify client to hide shown passkey 3778 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3779 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3780 } 3781 3782 // handle user cancel pairing? 3783 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3784 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3785 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3786 break; 3787 } 3788 3789 // wait for user action? 3790 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3791 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3792 break; 3793 } 3794 3795 // calculate and send local_confirm 3796 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3797 break; 3798 3799 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3800 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3801 sm_pdu_received_in_wrong_state(sm_conn); 3802 break;; 3803 } 3804 3805 // received random value 3806 reverse_128(&packet[1], setup->sm_peer_random); 3807 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3808 break; 3809 #endif 3810 3811 case SM_PH3_RECEIVE_KEYS: 3812 switch(sm_pdu_code){ 3813 case SM_CODE_ENCRYPTION_INFORMATION: 3814 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3815 reverse_128(&packet[1], setup->sm_peer_ltk); 3816 break; 3817 3818 case SM_CODE_MASTER_IDENTIFICATION: 3819 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3820 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3821 reverse_64(&packet[3], setup->sm_peer_rand); 3822 break; 3823 3824 case SM_CODE_IDENTITY_INFORMATION: 3825 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3826 reverse_128(&packet[1], setup->sm_peer_irk); 3827 break; 3828 3829 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3830 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3831 setup->sm_peer_addr_type = packet[1]; 3832 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3833 break; 3834 3835 case SM_CODE_SIGNING_INFORMATION: 3836 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3837 reverse_128(&packet[1], setup->sm_peer_csrk); 3838 break; 3839 default: 3840 // Unexpected PDU 3841 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3842 break; 3843 } 3844 // done with key distribution? 3845 if (sm_key_distribution_all_received(sm_conn)){ 3846 3847 sm_key_distribution_handle_all_received(sm_conn); 3848 3849 if (IS_RESPONDER(sm_conn->sm_role)){ 3850 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3851 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3852 } else { 3853 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3854 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3855 sm_done_for_handle(sm_conn->sm_handle); 3856 } 3857 } else { 3858 if (setup->sm_use_secure_connections){ 3859 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3860 } else { 3861 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3862 } 3863 } 3864 } 3865 break; 3866 default: 3867 // Unexpected PDU 3868 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3869 break; 3870 } 3871 3872 // try to send preparared packet 3873 sm_run(); 3874 } 3875 3876 // Security Manager Client API 3877 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 3878 sm_get_oob_data = get_oob_data_callback; 3879 } 3880 3881 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)){ 3882 sm_get_sc_oob_data = get_sc_oob_data_callback; 3883 } 3884 3885 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3886 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3887 } 3888 3889 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3890 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3891 } 3892 3893 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3894 sm_min_encryption_key_size = min_size; 3895 sm_max_encryption_key_size = max_size; 3896 } 3897 3898 void sm_set_authentication_requirements(uint8_t auth_req){ 3899 #ifndef ENABLE_LE_SECURE_CONNECTIONS 3900 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 3901 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 3902 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 3903 } 3904 #endif 3905 sm_auth_req = auth_req; 3906 } 3907 3908 void sm_set_io_capabilities(io_capability_t io_capability){ 3909 sm_io_capabilities = io_capability; 3910 } 3911 3912 #ifdef ENABLE_LE_PERIPHERAL 3913 void sm_set_request_security(int enable){ 3914 sm_slave_request_security = enable; 3915 } 3916 #endif 3917 3918 void sm_set_er(sm_key_t er){ 3919 memcpy(sm_persistent_er, er, 16); 3920 } 3921 3922 void sm_set_ir(sm_key_t ir){ 3923 memcpy(sm_persistent_ir, ir, 16); 3924 } 3925 3926 // Testing support only 3927 void sm_test_set_irk(sm_key_t irk){ 3928 memcpy(sm_persistent_irk, irk, 16); 3929 dkg_state = DKG_CALC_DHK; 3930 } 3931 3932 void sm_test_use_fixed_local_csrk(void){ 3933 test_use_fixed_local_csrk = 1; 3934 } 3935 3936 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3937 static void sm_ec_generated(void * arg){ 3938 UNUSED(arg); 3939 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3940 // trigger pairing if pending for ec key 3941 sm_run(); 3942 } 3943 static void sm_ec_generate_new_key(void){ 3944 log_info("sm: generate new ec key"); 3945 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 3946 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 3947 } 3948 #endif 3949 3950 #ifdef ENABLE_TESTING_SUPPORT 3951 void sm_test_set_pairing_failure(int reason){ 3952 test_pairing_failure = reason; 3953 } 3954 #endif 3955 3956 void sm_init(void){ 3957 // set default ER and IR values (should be unique - set by app or sm later using TLV) 3958 sm_er_ir_set_default(); 3959 3960 // defaults 3961 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3962 | SM_STK_GENERATION_METHOD_OOB 3963 | SM_STK_GENERATION_METHOD_PASSKEY 3964 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3965 3966 sm_max_encryption_key_size = 16; 3967 sm_min_encryption_key_size = 7; 3968 3969 sm_fixed_passkey_in_display_role = 0xffffffff; 3970 sm_reconstruct_ltk_without_le_device_db_entry = 1; 3971 3972 #ifdef USE_CMAC_ENGINE 3973 sm_cmac_active = 0; 3974 #endif 3975 dkg_state = DKG_W4_WORKING; 3976 rau_state = RAU_IDLE; 3977 sm_aes128_state = SM_AES128_IDLE; 3978 sm_address_resolution_test = -1; // no private address to resolve yet 3979 sm_address_resolution_ah_calculation_active = 0; 3980 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3981 sm_address_resolution_general_queue = NULL; 3982 3983 gap_random_adress_update_period = 15 * 60 * 1000L; 3984 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3985 3986 test_use_fixed_local_csrk = 0; 3987 3988 // register for HCI Events from HCI 3989 hci_event_callback_registration.callback = &sm_event_packet_handler; 3990 hci_add_event_handler(&hci_event_callback_registration); 3991 3992 // 3993 btstack_crypto_init(); 3994 3995 // init le_device_db 3996 le_device_db_init(); 3997 3998 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3999 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4000 4001 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4002 sm_ec_generate_new_key(); 4003 #endif 4004 } 4005 4006 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4007 sm_fixed_passkey_in_display_role = passkey; 4008 } 4009 4010 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4011 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4012 } 4013 4014 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4015 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4016 if (!hci_con) return NULL; 4017 return &hci_con->sm_connection; 4018 } 4019 4020 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4021 switch (sm_conn->sm_engine_state){ 4022 case SM_GENERAL_IDLE: 4023 case SM_RESPONDER_IDLE: 4024 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4025 sm_run(); 4026 break; 4027 default: 4028 break; 4029 } 4030 } 4031 4032 /** 4033 * @brief Trigger Security Request 4034 */ 4035 void sm_send_security_request(hci_con_handle_t con_handle){ 4036 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4037 if (!sm_conn) return; 4038 sm_send_security_request_for_connection(sm_conn); 4039 } 4040 4041 // request pairing 4042 void sm_request_pairing(hci_con_handle_t con_handle){ 4043 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4044 if (!sm_conn) return; // wrong connection 4045 4046 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4047 if (IS_RESPONDER(sm_conn->sm_role)){ 4048 sm_send_security_request_for_connection(sm_conn); 4049 } else { 4050 // used as a trigger to start central/master/initiator security procedures 4051 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4052 uint8_t ltk[16]; 4053 switch (sm_conn->sm_irk_lookup_state){ 4054 case IRK_LOOKUP_SUCCEEDED: 4055 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4056 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4057 log_info("have ltk %u", !sm_is_null_key(ltk)); 4058 // trigger 'pairing complete' event on encryption change 4059 sm_conn->sm_pairing_requested = 1; 4060 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4061 break; 4062 #endif 4063 /* explicit fall-through */ 4064 4065 case IRK_LOOKUP_FAILED: 4066 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4067 break; 4068 default: 4069 log_info("irk lookup pending"); 4070 sm_conn->sm_pairing_requested = 1; 4071 break; 4072 } 4073 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4074 sm_conn->sm_pairing_requested = 1; 4075 } 4076 } 4077 sm_run(); 4078 } 4079 4080 // called by client app on authorization request 4081 void sm_authorization_decline(hci_con_handle_t con_handle){ 4082 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4083 if (!sm_conn) return; // wrong connection 4084 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4085 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4086 } 4087 4088 void sm_authorization_grant(hci_con_handle_t con_handle){ 4089 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4090 if (!sm_conn) return; // wrong connection 4091 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4092 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4093 } 4094 4095 // GAP Bonding API 4096 4097 void sm_bonding_decline(hci_con_handle_t con_handle){ 4098 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4099 if (!sm_conn) return; // wrong connection 4100 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4101 log_info("decline, state %u", sm_conn->sm_engine_state); 4102 switch(sm_conn->sm_engine_state){ 4103 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4104 case SM_SC_W4_USER_RESPONSE: 4105 case SM_SC_W4_CONFIRMATION: 4106 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4107 #endif 4108 case SM_PH1_W4_USER_RESPONSE: 4109 switch (setup->sm_stk_generation_method){ 4110 case PK_RESP_INPUT: 4111 case PK_INIT_INPUT: 4112 case PK_BOTH_INPUT: 4113 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4114 break; 4115 case NUMERIC_COMPARISON: 4116 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4117 break; 4118 case JUST_WORKS: 4119 case OOB: 4120 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4121 break; 4122 } 4123 break; 4124 default: 4125 break; 4126 } 4127 sm_run(); 4128 } 4129 4130 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4131 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4132 if (!sm_conn) return; // wrong connection 4133 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4134 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4135 if (setup->sm_use_secure_connections){ 4136 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4137 } else { 4138 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4139 } 4140 } 4141 4142 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4143 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4144 sm_sc_prepare_dhkey_check(sm_conn); 4145 } 4146 #endif 4147 4148 sm_run(); 4149 } 4150 4151 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4152 // for now, it's the same 4153 sm_just_works_confirm(con_handle); 4154 } 4155 4156 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4157 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4158 if (!sm_conn) return; // wrong connection 4159 sm_reset_tk(); 4160 big_endian_store_32(setup->sm_tk, 12, passkey); 4161 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4162 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4163 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4164 } 4165 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4166 memcpy(setup->sm_ra, setup->sm_tk, 16); 4167 memcpy(setup->sm_rb, setup->sm_tk, 16); 4168 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4169 sm_sc_start_calculating_local_confirm(sm_conn); 4170 } 4171 #endif 4172 sm_run(); 4173 } 4174 4175 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4176 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4177 if (!sm_conn) return; // wrong connection 4178 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4179 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4180 uint8_t flags = setup->sm_keypress_notification & 0x1f; 4181 switch (action){ 4182 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4183 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4184 flags |= (1 << action); 4185 break; 4186 case SM_KEYPRESS_PASSKEY_CLEARED: 4187 // clear counter, keypress & erased flags + set passkey cleared 4188 flags = (flags & 0x19) | (1 << SM_KEYPRESS_PASSKEY_CLEARED); 4189 break; 4190 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4191 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4192 // erase actions queued 4193 num_actions--; 4194 if (num_actions == 0){ 4195 // clear counter, keypress & erased flags 4196 flags &= 0x19; 4197 } 4198 break; 4199 } 4200 num_actions++; 4201 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4202 break; 4203 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4204 if (flags & (1 << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4205 // enter actions queued 4206 num_actions--; 4207 if (num_actions == 0){ 4208 // clear counter, keypress & erased flags 4209 flags &= 0x19; 4210 } 4211 break; 4212 } 4213 num_actions++; 4214 flags |= (1 << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4215 break; 4216 default: 4217 break; 4218 } 4219 setup->sm_keypress_notification = (num_actions << 5) | flags; 4220 sm_run(); 4221 } 4222 4223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4224 static void sm_handle_random_result_oob(void * arg){ 4225 UNUSED(arg); 4226 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4227 sm_run(); 4228 } 4229 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4230 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4231 sm_sc_oob_callback = callback; 4232 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4233 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4234 return 0; 4235 } 4236 #endif 4237 4238 /** 4239 * @brief Get Identity Resolving state 4240 * @param con_handle 4241 * @return irk_lookup_state_t 4242 */ 4243 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4244 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4245 if (!sm_conn) return IRK_LOOKUP_IDLE; 4246 return sm_conn->sm_irk_lookup_state; 4247 } 4248 4249 /** 4250 * @brief Identify device in LE Device DB 4251 * @param handle 4252 * @returns index from le_device_db or -1 if not found/identified 4253 */ 4254 int sm_le_device_index(hci_con_handle_t con_handle ){ 4255 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4256 if (!sm_conn) return -1; 4257 return sm_conn->sm_le_db_index; 4258 } 4259 4260 static int gap_random_address_type_requires_updates(void){ 4261 switch (gap_random_adress_type){ 4262 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4263 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4264 return 0; 4265 default: 4266 return 1; 4267 } 4268 } 4269 4270 static uint8_t own_address_type(void){ 4271 switch (gap_random_adress_type){ 4272 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4273 return BD_ADDR_TYPE_LE_PUBLIC; 4274 default: 4275 return BD_ADDR_TYPE_LE_RANDOM; 4276 } 4277 } 4278 4279 // GAP LE API 4280 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4281 gap_random_address_update_stop(); 4282 gap_random_adress_type = random_address_type; 4283 hci_le_set_own_address_type(own_address_type()); 4284 if (!gap_random_address_type_requires_updates()) return; 4285 gap_random_address_update_start(); 4286 gap_random_address_trigger(); 4287 } 4288 4289 gap_random_address_type_t gap_random_address_get_mode(void){ 4290 return gap_random_adress_type; 4291 } 4292 4293 void gap_random_address_set_update_period(int period_ms){ 4294 gap_random_adress_update_period = period_ms; 4295 if (!gap_random_address_type_requires_updates()) return; 4296 gap_random_address_update_stop(); 4297 gap_random_address_update_start(); 4298 } 4299 4300 void gap_random_address_set(bd_addr_t addr){ 4301 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4302 memcpy(sm_random_address, addr, 6); 4303 rau_state = RAU_SET_ADDRESS; 4304 sm_run(); 4305 } 4306 4307 #ifdef ENABLE_LE_PERIPHERAL 4308 /* 4309 * @brief Set Advertisement Paramters 4310 * @param adv_int_min 4311 * @param adv_int_max 4312 * @param adv_type 4313 * @param direct_address_type 4314 * @param direct_address 4315 * @param channel_map 4316 * @param filter_policy 4317 * 4318 * @note own_address_type is used from gap_random_address_set_mode 4319 */ 4320 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4321 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4322 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4323 direct_address_typ, direct_address, channel_map, filter_policy); 4324 } 4325 #endif 4326 4327 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4328 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4329 // wrong connection 4330 if (!sm_conn) return 0; 4331 // already encrypted 4332 if (sm_conn->sm_connection_encrypted) return 0; 4333 // only central can re-encrypt 4334 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4335 // irk status? 4336 switch(sm_conn->sm_irk_lookup_state){ 4337 case IRK_LOOKUP_FAILED: 4338 // done, cannot setup encryption 4339 return 0; 4340 case IRK_LOOKUP_SUCCEEDED: 4341 break; 4342 default: 4343 // IR Lookup pending 4344 return 1; 4345 } 4346 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4347 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4348 } 4349