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 <stdio.h> 41 #include <string.h> 42 #include <inttypes.h> 43 44 #include "ble/le_device_db.h" 45 #include "ble/core.h" 46 #include "ble/sm.h" 47 #include "bluetooth_company_id.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "gap.h" 53 #include "hci.h" 54 #include "hci_dump.h" 55 #include "l2cap.h" 56 57 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 58 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 59 #endif 60 61 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 62 #define IS_RESPONDER(role) (role) 63 #else 64 #ifdef ENABLE_LE_CENTRAL 65 // only central - never responder (avoid 'unused variable' warnings) 66 #define IS_RESPONDER(role) (0 && role) 67 #else 68 // only peripheral - always responder (avoid 'unused variable' warnings) 69 #define IS_RESPONDER(role) (1 || role) 70 #endif 71 #endif 72 73 #ifdef ENABLE_LE_SECURE_CONNECTIONS 74 // assert SM Public Key can be sent/received 75 #if HCI_ACL_PAYLOAD_SIZE < 69 76 #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" 77 #endif 78 79 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 80 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 81 #else 82 #define USE_MICROECC_FOR_ECDH 83 #endif 84 #endif 85 86 // Software ECDH implementation provided by micro-ecc 87 #ifdef USE_MICROECC_FOR_ECDH 88 #include "uECC.h" 89 #endif 90 91 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 92 #define ENABLE_CMAC_ENGINE 93 #endif 94 95 // 96 // SM internal types and globals 97 // 98 99 typedef enum { 100 DKG_W4_WORKING, 101 DKG_CALC_IRK, 102 DKG_W4_IRK, 103 DKG_CALC_DHK, 104 DKG_W4_DHK, 105 DKG_READY 106 } derived_key_generation_t; 107 108 typedef enum { 109 RAU_W4_WORKING, 110 RAU_IDLE, 111 RAU_GET_RANDOM, 112 RAU_W4_RANDOM, 113 RAU_GET_ENC, 114 RAU_W4_ENC, 115 RAU_SET_ADDRESS, 116 } random_address_update_t; 117 118 typedef enum { 119 CMAC_IDLE, 120 CMAC_CALC_SUBKEYS, 121 CMAC_W4_SUBKEYS, 122 CMAC_CALC_MI, 123 CMAC_W4_MI, 124 CMAC_CALC_MLAST, 125 CMAC_W4_MLAST 126 } cmac_state_t; 127 128 typedef enum { 129 JUST_WORKS, 130 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 131 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 132 OK_BOTH_INPUT, // Only input on both, both input PK 133 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 134 OOB // OOB available on both sides 135 } stk_generation_method_t; 136 137 typedef enum { 138 SM_USER_RESPONSE_IDLE, 139 SM_USER_RESPONSE_PENDING, 140 SM_USER_RESPONSE_CONFIRM, 141 SM_USER_RESPONSE_PASSKEY, 142 SM_USER_RESPONSE_DECLINE 143 } sm_user_response_t; 144 145 typedef enum { 146 SM_AES128_IDLE, 147 SM_AES128_ACTIVE 148 } sm_aes128_state_t; 149 150 typedef enum { 151 ADDRESS_RESOLUTION_IDLE, 152 ADDRESS_RESOLUTION_GENERAL, 153 ADDRESS_RESOLUTION_FOR_CONNECTION, 154 } address_resolution_mode_t; 155 156 typedef enum { 157 ADDRESS_RESOLUTION_SUCEEDED, 158 ADDRESS_RESOLUTION_FAILED, 159 } address_resolution_event_t; 160 161 typedef enum { 162 EC_KEY_GENERATION_IDLE, 163 EC_KEY_GENERATION_ACTIVE, 164 EC_KEY_GENERATION_W4_KEY, 165 EC_KEY_GENERATION_DONE, 166 } ec_key_generation_state_t; 167 168 typedef enum { 169 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 170 } sm_state_var_t; 171 172 // 173 // GLOBAL DATA 174 // 175 176 static uint8_t test_use_fixed_local_csrk; 177 178 // configuration 179 static uint8_t sm_accepted_stk_generation_methods; 180 static uint8_t sm_max_encryption_key_size; 181 static uint8_t sm_min_encryption_key_size; 182 static uint8_t sm_auth_req = 0; 183 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 184 static uint8_t sm_slave_request_security; 185 #ifdef ENABLE_LE_SECURE_CONNECTIONS 186 static uint8_t sm_have_ec_keypair; 187 #endif 188 189 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 190 static sm_key_t sm_persistent_er; 191 static sm_key_t sm_persistent_ir; 192 193 // derived from sm_persistent_ir 194 static sm_key_t sm_persistent_dhk; 195 static sm_key_t sm_persistent_irk; 196 static uint8_t sm_persistent_irk_ready = 0; // used for testing 197 static derived_key_generation_t dkg_state; 198 199 // derived from sm_persistent_er 200 // .. 201 202 // random address update 203 static random_address_update_t rau_state; 204 static bd_addr_t sm_random_address; 205 206 // CMAC Calculation: General 207 #ifdef ENABLE_CMAC_ENGINE 208 static cmac_state_t sm_cmac_state; 209 static uint16_t sm_cmac_message_len; 210 static sm_key_t sm_cmac_k; 211 static sm_key_t sm_cmac_x; 212 static sm_key_t sm_cmac_m_last; 213 static uint8_t sm_cmac_block_current; 214 static uint8_t sm_cmac_block_count; 215 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 216 static void (*sm_cmac_done_handler)(uint8_t * hash); 217 #endif 218 219 // CMAC for ATT Signed Writes 220 #ifdef ENABLE_LE_SIGNED_WRITE 221 static uint8_t sm_cmac_header[3]; 222 static const uint8_t * sm_cmac_message; 223 static uint8_t sm_cmac_sign_counter[4]; 224 #endif 225 226 // CMAC for Secure Connection functions 227 #ifdef ENABLE_LE_SECURE_CONNECTIONS 228 static sm_connection_t * sm_cmac_connection; 229 static uint8_t sm_cmac_sc_buffer[80]; 230 #endif 231 232 // resolvable private address lookup / CSRK calculation 233 static int sm_address_resolution_test; 234 static int sm_address_resolution_ah_calculation_active; 235 static uint8_t sm_address_resolution_addr_type; 236 static bd_addr_t sm_address_resolution_address; 237 static void * sm_address_resolution_context; 238 static address_resolution_mode_t sm_address_resolution_mode; 239 static btstack_linked_list_t sm_address_resolution_general_queue; 240 241 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 242 static sm_aes128_state_t sm_aes128_state; 243 static void * sm_aes128_context; 244 245 // use aes128 provided by MCU - not needed usually 246 #ifdef HAVE_AES128 247 static uint8_t aes128_result_flipped[16]; 248 static btstack_timer_source_t aes128_timer; 249 void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result); 250 #endif 251 252 // random engine. store context (ususally sm_connection_t) 253 static void * sm_random_context; 254 255 // to receive hci events 256 static btstack_packet_callback_registration_t hci_event_callback_registration; 257 258 /* to dispatch sm event */ 259 static btstack_linked_list_t sm_event_handlers; 260 261 // LE Secure Connections 262 #ifdef ENABLE_LE_SECURE_CONNECTIONS 263 static ec_key_generation_state_t ec_key_generation_state; 264 static uint8_t ec_d[32]; 265 static uint8_t ec_q[64]; 266 #endif 267 268 // 269 // Volume 3, Part H, Chapter 24 270 // "Security shall be initiated by the Security Manager in the device in the master role. 271 // The device in the slave role shall be the responding device." 272 // -> master := initiator, slave := responder 273 // 274 275 // data needed for security setup 276 typedef struct sm_setup_context { 277 278 btstack_timer_source_t sm_timeout; 279 280 // used in all phases 281 uint8_t sm_pairing_failed_reason; 282 283 // user response, (Phase 1 and/or 2) 284 uint8_t sm_user_response; 285 uint8_t sm_keypress_notification; 286 287 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 288 int sm_key_distribution_send_set; 289 int sm_key_distribution_received_set; 290 291 // Phase 2 (Pairing over SMP) 292 stk_generation_method_t sm_stk_generation_method; 293 sm_key_t sm_tk; 294 uint8_t sm_use_secure_connections; 295 296 sm_key_t sm_c1_t3_value; // c1 calculation 297 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 298 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 299 sm_key_t sm_local_random; 300 sm_key_t sm_local_confirm; 301 sm_key_t sm_peer_random; 302 sm_key_t sm_peer_confirm; 303 uint8_t sm_m_addr_type; // address and type can be removed 304 uint8_t sm_s_addr_type; // '' 305 bd_addr_t sm_m_address; // '' 306 bd_addr_t sm_s_address; // '' 307 sm_key_t sm_ltk; 308 309 uint8_t sm_state_vars; 310 #ifdef ENABLE_LE_SECURE_CONNECTIONS 311 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 312 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 313 sm_key_t sm_local_nonce; // might be combined with sm_local_random 314 sm_key_t sm_peer_dhkey_check; 315 sm_key_t sm_local_dhkey_check; 316 sm_key_t sm_ra; 317 sm_key_t sm_rb; 318 sm_key_t sm_t; // used for f5 and h6 319 sm_key_t sm_mackey; 320 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 321 #endif 322 323 // Phase 3 324 325 // key distribution, we generate 326 uint16_t sm_local_y; 327 uint16_t sm_local_div; 328 uint16_t sm_local_ediv; 329 uint8_t sm_local_rand[8]; 330 sm_key_t sm_local_ltk; 331 sm_key_t sm_local_csrk; 332 sm_key_t sm_local_irk; 333 // sm_local_address/addr_type not needed 334 335 // key distribution, received from peer 336 uint16_t sm_peer_y; 337 uint16_t sm_peer_div; 338 uint16_t sm_peer_ediv; 339 uint8_t sm_peer_rand[8]; 340 sm_key_t sm_peer_ltk; 341 sm_key_t sm_peer_irk; 342 sm_key_t sm_peer_csrk; 343 uint8_t sm_peer_addr_type; 344 bd_addr_t sm_peer_address; 345 346 } sm_setup_context_t; 347 348 // 349 static sm_setup_context_t the_setup; 350 static sm_setup_context_t * setup = &the_setup; 351 352 // active connection - the one for which the_setup is used for 353 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 354 355 // @returns 1 if oob data is available 356 // stores oob data in provided 16 byte buffer if not null 357 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 358 359 // horizontal: initiator capabilities 360 // vertial: responder capabilities 361 static const stk_generation_method_t stk_generation_method [5] [5] = { 362 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 363 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 364 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 365 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 366 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 367 }; 368 369 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 370 #ifdef ENABLE_LE_SECURE_CONNECTIONS 371 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 372 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 373 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 374 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 375 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 376 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 377 }; 378 #endif 379 380 static void sm_run(void); 381 static void sm_done_for_handle(hci_con_handle_t con_handle); 382 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 383 static inline int sm_calc_actual_encryption_key_size(int other); 384 static int sm_validate_stk_generation_method(void); 385 static void sm_handle_encryption_result(uint8_t * data); 386 387 static void log_info_hex16(const char * name, uint16_t value){ 388 log_info("%-6s 0x%04x", name, value); 389 } 390 391 // @returns 1 if all bytes are 0 392 static int sm_is_null(uint8_t * data, int size){ 393 int i; 394 for (i=0; i < size ; i++){ 395 if (data[i]) return 0; 396 } 397 return 1; 398 } 399 400 static int sm_is_null_random(uint8_t random[8]){ 401 return sm_is_null(random, 8); 402 } 403 404 static int sm_is_null_key(uint8_t * key){ 405 return sm_is_null(key, 16); 406 } 407 408 // Key utils 409 static void sm_reset_tk(void){ 410 int i; 411 for (i=0;i<16;i++){ 412 setup->sm_tk[i] = 0; 413 } 414 } 415 416 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 417 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 418 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 419 int i; 420 for (i = max_encryption_size ; i < 16 ; i++){ 421 key[15-i] = 0; 422 } 423 } 424 425 // SMP Timeout implementation 426 427 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 428 // the Security Manager Timer shall be reset and started. 429 // 430 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 431 // 432 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 433 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 434 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 435 // established. 436 437 static void sm_timeout_handler(btstack_timer_source_t * timer){ 438 log_info("SM timeout"); 439 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 440 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 441 sm_done_for_handle(sm_conn->sm_handle); 442 443 // trigger handling of next ready connection 444 sm_run(); 445 } 446 static void sm_timeout_start(sm_connection_t * sm_conn){ 447 btstack_run_loop_remove_timer(&setup->sm_timeout); 448 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 449 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 450 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 451 btstack_run_loop_add_timer(&setup->sm_timeout); 452 } 453 static void sm_timeout_stop(void){ 454 btstack_run_loop_remove_timer(&setup->sm_timeout); 455 } 456 static void sm_timeout_reset(sm_connection_t * sm_conn){ 457 sm_timeout_stop(); 458 sm_timeout_start(sm_conn); 459 } 460 461 // end of sm timeout 462 463 // GAP Random Address updates 464 static gap_random_address_type_t gap_random_adress_type; 465 static btstack_timer_source_t gap_random_address_update_timer; 466 static uint32_t gap_random_adress_update_period; 467 468 static void gap_random_address_trigger(void){ 469 if (rau_state != RAU_IDLE) return; 470 log_info("gap_random_address_trigger"); 471 rau_state = RAU_GET_RANDOM; 472 sm_run(); 473 } 474 475 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 476 UNUSED(timer); 477 478 log_info("GAP Random Address Update due"); 479 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 480 btstack_run_loop_add_timer(&gap_random_address_update_timer); 481 gap_random_address_trigger(); 482 } 483 484 static void gap_random_address_update_start(void){ 485 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 486 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 487 btstack_run_loop_add_timer(&gap_random_address_update_timer); 488 } 489 490 static void gap_random_address_update_stop(void){ 491 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 492 } 493 494 495 static void sm_random_start(void * context){ 496 sm_random_context = context; 497 hci_send_cmd(&hci_le_rand); 498 } 499 500 #ifdef HAVE_AES128 501 static void aes128_completed(btstack_timer_source_t * ts){ 502 UNUSED(ts); 503 sm_handle_encryption_result(&aes128_result_flipped[0]); 504 sm_run(); 505 } 506 #endif 507 508 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 509 // context is made availabe to aes128 result handler by this 510 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 511 sm_aes128_state = SM_AES128_ACTIVE; 512 sm_aes128_context = context; 513 514 #ifdef HAVE_AES128 515 // calc result directly 516 sm_key_t result; 517 btstack_aes128_calc(key, plaintext, result); 518 519 // log 520 log_info_key("key", key); 521 log_info_key("txt", plaintext); 522 log_info_key("res", result); 523 524 // flip 525 reverse_128(&result[0], &aes128_result_flipped[0]); 526 527 // deliver via timer 528 btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed); 529 btstack_run_loop_set_timer(&aes128_timer, 0); // no delay 530 btstack_run_loop_add_timer(&aes128_timer); 531 #else 532 sm_key_t key_flipped, plaintext_flipped; 533 reverse_128(key, key_flipped); 534 reverse_128(plaintext, plaintext_flipped); 535 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 536 #endif 537 } 538 539 // ah(k,r) helper 540 // r = padding || r 541 // r - 24 bit value 542 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 543 // r'= padding || r 544 memset(r_prime, 0, 16); 545 memcpy(&r_prime[13], r, 3); 546 } 547 548 // d1 helper 549 // d' = padding || r || d 550 // d,r - 16 bit values 551 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 552 // d'= padding || r || d 553 memset(d1_prime, 0, 16); 554 big_endian_store_16(d1_prime, 12, r); 555 big_endian_store_16(d1_prime, 14, d); 556 } 557 558 // dm helper 559 // r’ = padding || r 560 // r - 64 bit value 561 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 562 memset(r_prime, 0, 16); 563 memcpy(&r_prime[8], r, 8); 564 } 565 566 // calculate arguments for first AES128 operation in C1 function 567 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){ 568 569 // p1 = pres || preq || rat’ || iat’ 570 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 571 // cant octet of pres becomes the most significant octet of p1. 572 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 573 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 574 // p1 is 0x05000800000302070710000001010001." 575 576 sm_key_t p1; 577 reverse_56(pres, &p1[0]); 578 reverse_56(preq, &p1[7]); 579 p1[14] = rat; 580 p1[15] = iat; 581 log_info_key("p1", p1); 582 log_info_key("r", r); 583 584 // t1 = r xor p1 585 int i; 586 for (i=0;i<16;i++){ 587 t1[i] = r[i] ^ p1[i]; 588 } 589 log_info_key("t1", t1); 590 } 591 592 // calculate arguments for second AES128 operation in C1 function 593 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 594 // p2 = padding || ia || ra 595 // "The least significant octet of ra becomes the least significant octet of p2 and 596 // the most significant octet of padding becomes the most significant octet of p2. 597 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 598 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 599 600 sm_key_t p2; 601 memset(p2, 0, 16); 602 memcpy(&p2[4], ia, 6); 603 memcpy(&p2[10], ra, 6); 604 log_info_key("p2", p2); 605 606 // c1 = e(k, t2_xor_p2) 607 int i; 608 for (i=0;i<16;i++){ 609 t3[i] = t2[i] ^ p2[i]; 610 } 611 log_info_key("t3", t3); 612 } 613 614 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 615 log_info_key("r1", r1); 616 log_info_key("r2", r2); 617 memcpy(&r_prime[8], &r2[8], 8); 618 memcpy(&r_prime[0], &r1[8], 8); 619 } 620 621 #ifdef ENABLE_LE_SECURE_CONNECTIONS 622 // Software implementations of crypto toolbox for LE Secure Connection 623 // TODO: replace with code to use AES Engine of HCI Controller 624 typedef uint8_t sm_key24_t[3]; 625 typedef uint8_t sm_key56_t[7]; 626 typedef uint8_t sm_key256_t[32]; 627 628 #if 0 629 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 630 uint32_t rk[RKLENGTH(KEYBITS)]; 631 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 632 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 633 } 634 635 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 636 memcpy(k1, k0, 16); 637 sm_shift_left_by_one_bit_inplace(16, k1); 638 if (k0[0] & 0x80){ 639 k1[15] ^= 0x87; 640 } 641 memcpy(k2, k1, 16); 642 sm_shift_left_by_one_bit_inplace(16, k2); 643 if (k1[0] & 0x80){ 644 k2[15] ^= 0x87; 645 } 646 } 647 648 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 649 sm_key_t k0, k1, k2, zero; 650 memset(zero, 0, 16); 651 652 aes128_calc_cyphertext(key, zero, k0); 653 calc_subkeys(k0, k1, k2); 654 655 int cmac_block_count = (cmac_message_len + 15) / 16; 656 657 // step 3: .. 658 if (cmac_block_count==0){ 659 cmac_block_count = 1; 660 } 661 662 // step 4: set m_last 663 sm_key_t cmac_m_last; 664 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 665 int i; 666 if (sm_cmac_last_block_complete){ 667 for (i=0;i<16;i++){ 668 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 669 } 670 } else { 671 int valid_octets_in_last_block = cmac_message_len & 0x0f; 672 for (i=0;i<16;i++){ 673 if (i < valid_octets_in_last_block){ 674 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 675 continue; 676 } 677 if (i == valid_octets_in_last_block){ 678 cmac_m_last[i] = 0x80 ^ k2[i]; 679 continue; 680 } 681 cmac_m_last[i] = k2[i]; 682 } 683 } 684 685 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 686 // LOG_KEY(cmac_m_last); 687 688 // Step 5 689 sm_key_t cmac_x; 690 memset(cmac_x, 0, 16); 691 692 // Step 6 693 sm_key_t sm_cmac_y; 694 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 695 for (i=0;i<16;i++){ 696 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 697 } 698 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 699 } 700 for (i=0;i<16;i++){ 701 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 702 } 703 704 // Step 7 705 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 706 } 707 #endif 708 #endif 709 710 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){ 711 event[0] = type; 712 event[1] = event_size - 2; 713 little_endian_store_16(event, 2, con_handle); 714 event[4] = addr_type; 715 reverse_bd_addr(address, &event[5]); 716 } 717 718 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 719 UNUSED(channel); 720 721 // log event 722 hci_dump_packet(packet_type, 1, packet, size); 723 // dispatch to all event handlers 724 btstack_linked_list_iterator_t it; 725 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 726 while (btstack_linked_list_iterator_has_next(&it)){ 727 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 728 entry->callback(packet_type, 0, packet, size); 729 } 730 } 731 732 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 733 uint8_t event[11]; 734 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 735 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 736 } 737 738 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){ 739 uint8_t event[15]; 740 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 741 little_endian_store_32(event, 11, passkey); 742 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 743 } 744 745 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){ 746 // fetch addr and addr type from db 747 bd_addr_t identity_address; 748 int identity_address_type; 749 le_device_db_info(index, &identity_address_type, identity_address, NULL); 750 751 uint8_t event[19]; 752 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 753 event[11] = identity_address_type; 754 reverse_bd_addr(identity_address, &event[12]); 755 event[18] = index; 756 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 757 } 758 759 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 760 761 uint8_t event[18]; 762 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 763 event[11] = result; 764 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 765 } 766 767 // decide on stk generation based on 768 // - pairing request 769 // - io capabilities 770 // - OOB data availability 771 static void sm_setup_tk(void){ 772 773 // default: just works 774 setup->sm_stk_generation_method = JUST_WORKS; 775 776 #ifdef ENABLE_LE_SECURE_CONNECTIONS 777 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 778 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 779 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 780 memset(setup->sm_ra, 0, 16); 781 memset(setup->sm_rb, 0, 16); 782 #else 783 setup->sm_use_secure_connections = 0; 784 #endif 785 786 // If both devices have not set the MITM option in the Authentication Requirements 787 // Flags, then the IO capabilities shall be ignored and the Just Works association 788 // model shall be used. 789 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 790 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 791 log_info("SM: MITM not required by both -> JUST WORKS"); 792 return; 793 } 794 795 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 796 797 // If both devices have out of band authentication data, then the Authentication 798 // Requirements Flags shall be ignored when selecting the pairing method and the 799 // Out of Band pairing method shall be used. 800 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 801 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 802 log_info("SM: have OOB data"); 803 log_info_key("OOB", setup->sm_tk); 804 setup->sm_stk_generation_method = OOB; 805 return; 806 } 807 808 // Reset TK as it has been setup in sm_init_setup 809 sm_reset_tk(); 810 811 // Also use just works if unknown io capabilites 812 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)){ 813 return; 814 } 815 816 // Otherwise the IO capabilities of the devices shall be used to determine the 817 // pairing method as defined in Table 2.4. 818 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 819 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 820 821 #ifdef ENABLE_LE_SECURE_CONNECTIONS 822 // table not define by default 823 if (setup->sm_use_secure_connections){ 824 generation_method = stk_generation_method_with_secure_connection; 825 } 826 #endif 827 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)]; 828 829 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 830 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); 831 } 832 833 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 834 int flags = 0; 835 if (key_set & SM_KEYDIST_ENC_KEY){ 836 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 837 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 838 } 839 if (key_set & SM_KEYDIST_ID_KEY){ 840 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 841 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 842 } 843 if (key_set & SM_KEYDIST_SIGN){ 844 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 845 } 846 return flags; 847 } 848 849 static void sm_setup_key_distribution(uint8_t key_set){ 850 setup->sm_key_distribution_received_set = 0; 851 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 852 } 853 854 // CSRK Key Lookup 855 856 857 static int sm_address_resolution_idle(void){ 858 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 859 } 860 861 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){ 862 memcpy(sm_address_resolution_address, addr, 6); 863 sm_address_resolution_addr_type = addr_type; 864 sm_address_resolution_test = 0; 865 sm_address_resolution_mode = mode; 866 sm_address_resolution_context = context; 867 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 868 } 869 870 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 871 // check if already in list 872 btstack_linked_list_iterator_t it; 873 sm_lookup_entry_t * entry; 874 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 875 while(btstack_linked_list_iterator_has_next(&it)){ 876 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 877 if (entry->address_type != address_type) continue; 878 if (memcmp(entry->address, address, 6)) continue; 879 // already in list 880 return BTSTACK_BUSY; 881 } 882 entry = btstack_memory_sm_lookup_entry_get(); 883 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 884 entry->address_type = (bd_addr_type_t) address_type; 885 memcpy(entry->address, address, 6); 886 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 887 sm_run(); 888 return 0; 889 } 890 891 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 892 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 893 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 894 } 895 static inline void dkg_next_state(void){ 896 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 897 } 898 static inline void rau_next_state(void){ 899 rau_state = (random_address_update_t) (((int)rau_state) + 1); 900 } 901 902 // CMAC calculation using AES Engine 903 #ifdef ENABLE_CMAC_ENGINE 904 905 static inline void sm_cmac_next_state(void){ 906 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 907 } 908 909 static int sm_cmac_last_block_complete(void){ 910 if (sm_cmac_message_len == 0) return 0; 911 return (sm_cmac_message_len & 0x0f) == 0; 912 } 913 914 int sm_cmac_ready(void){ 915 return sm_cmac_state == CMAC_IDLE; 916 } 917 918 // generic cmac calculation 919 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 920 // Generalized CMAC 921 memcpy(sm_cmac_k, key, 16); 922 memset(sm_cmac_x, 0, 16); 923 sm_cmac_block_current = 0; 924 sm_cmac_message_len = message_len; 925 sm_cmac_done_handler = done_callback; 926 sm_cmac_get_byte = get_byte_callback; 927 928 // step 2: n := ceil(len/const_Bsize); 929 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 930 931 // step 3: .. 932 if (sm_cmac_block_count==0){ 933 sm_cmac_block_count = 1; 934 } 935 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 936 937 // first, we need to compute l for k1, k2, and m_last 938 sm_cmac_state = CMAC_CALC_SUBKEYS; 939 940 // let's go 941 sm_run(); 942 } 943 #endif 944 945 // cmac for ATT Message signing 946 #ifdef ENABLE_LE_SIGNED_WRITE 947 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 948 if (offset >= sm_cmac_message_len) { 949 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 950 return 0; 951 } 952 953 offset = sm_cmac_message_len - 1 - offset; 954 955 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 956 if (offset < 3){ 957 return sm_cmac_header[offset]; 958 } 959 int actual_message_len_incl_header = sm_cmac_message_len - 4; 960 if (offset < actual_message_len_incl_header){ 961 return sm_cmac_message[offset - 3]; 962 } 963 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 964 } 965 966 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)){ 967 // ATT Message Signing 968 sm_cmac_header[0] = opcode; 969 little_endian_store_16(sm_cmac_header, 1, con_handle); 970 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 971 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 972 sm_cmac_message = message; 973 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 974 } 975 #endif 976 977 #ifdef ENABLE_CMAC_ENGINE 978 static void sm_cmac_handle_aes_engine_ready(void){ 979 switch (sm_cmac_state){ 980 case CMAC_CALC_SUBKEYS: { 981 sm_key_t const_zero; 982 memset(const_zero, 0, 16); 983 sm_cmac_next_state(); 984 sm_aes128_start(sm_cmac_k, const_zero, NULL); 985 break; 986 } 987 case CMAC_CALC_MI: { 988 int j; 989 sm_key_t y; 990 for (j=0;j<16;j++){ 991 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 992 } 993 sm_cmac_block_current++; 994 sm_cmac_next_state(); 995 sm_aes128_start(sm_cmac_k, y, NULL); 996 break; 997 } 998 case CMAC_CALC_MLAST: { 999 int i; 1000 sm_key_t y; 1001 for (i=0;i<16;i++){ 1002 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1003 } 1004 log_info_key("Y", y); 1005 sm_cmac_block_current++; 1006 sm_cmac_next_state(); 1007 sm_aes128_start(sm_cmac_k, y, NULL); 1008 break; 1009 } 1010 default: 1011 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1012 break; 1013 } 1014 } 1015 1016 // CMAC Implementation using AES128 engine 1017 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1018 int i; 1019 int carry = 0; 1020 for (i=len-1; i >= 0 ; i--){ 1021 int new_carry = data[i] >> 7; 1022 data[i] = data[i] << 1 | carry; 1023 carry = new_carry; 1024 } 1025 } 1026 1027 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1028 switch (sm_cmac_state){ 1029 case CMAC_W4_SUBKEYS: { 1030 sm_key_t k1; 1031 memcpy(k1, data, 16); 1032 sm_shift_left_by_one_bit_inplace(16, k1); 1033 if (data[0] & 0x80){ 1034 k1[15] ^= 0x87; 1035 } 1036 sm_key_t k2; 1037 memcpy(k2, k1, 16); 1038 sm_shift_left_by_one_bit_inplace(16, k2); 1039 if (k1[0] & 0x80){ 1040 k2[15] ^= 0x87; 1041 } 1042 1043 log_info_key("k", sm_cmac_k); 1044 log_info_key("k1", k1); 1045 log_info_key("k2", k2); 1046 1047 // step 4: set m_last 1048 int i; 1049 if (sm_cmac_last_block_complete()){ 1050 for (i=0;i<16;i++){ 1051 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1052 } 1053 } else { 1054 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1055 for (i=0;i<16;i++){ 1056 if (i < valid_octets_in_last_block){ 1057 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1058 continue; 1059 } 1060 if (i == valid_octets_in_last_block){ 1061 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1062 continue; 1063 } 1064 sm_cmac_m_last[i] = k2[i]; 1065 } 1066 } 1067 1068 // next 1069 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1070 break; 1071 } 1072 case CMAC_W4_MI: 1073 memcpy(sm_cmac_x, data, 16); 1074 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1075 break; 1076 case CMAC_W4_MLAST: 1077 // done 1078 log_info("Setting CMAC Engine to IDLE"); 1079 sm_cmac_state = CMAC_IDLE; 1080 log_info_key("CMAC", data); 1081 sm_cmac_done_handler(data); 1082 break; 1083 default: 1084 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1085 break; 1086 } 1087 } 1088 #endif 1089 1090 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1091 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1092 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1093 switch (setup->sm_stk_generation_method){ 1094 case PK_RESP_INPUT: 1095 if (IS_RESPONDER(sm_conn->sm_role)){ 1096 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1097 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1098 } else { 1099 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)); 1100 } 1101 break; 1102 case PK_INIT_INPUT: 1103 if (IS_RESPONDER(sm_conn->sm_role)){ 1104 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)); 1105 } else { 1106 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1107 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1108 } 1109 break; 1110 case OK_BOTH_INPUT: 1111 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1112 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1113 break; 1114 case NK_BOTH_INPUT: 1115 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1116 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)); 1117 break; 1118 case JUST_WORKS: 1119 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1120 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1121 break; 1122 case OOB: 1123 // client already provided OOB data, let's skip notification. 1124 break; 1125 } 1126 } 1127 1128 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1129 int recv_flags; 1130 if (IS_RESPONDER(sm_conn->sm_role)){ 1131 // slave / responder 1132 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1133 } else { 1134 // master / initiator 1135 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1136 } 1137 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1138 return recv_flags == setup->sm_key_distribution_received_set; 1139 } 1140 1141 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1142 if (sm_active_connection_handle == con_handle){ 1143 sm_timeout_stop(); 1144 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1145 log_info("sm: connection 0x%x released setup context", con_handle); 1146 } 1147 } 1148 1149 static int sm_key_distribution_flags_for_auth_req(void){ 1150 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1151 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1152 // encryption information only if bonding requested 1153 flags |= SM_KEYDIST_ENC_KEY; 1154 } 1155 return flags; 1156 } 1157 1158 static void sm_reset_setup(void){ 1159 // fill in sm setup 1160 setup->sm_state_vars = 0; 1161 setup->sm_keypress_notification = 0xff; 1162 sm_reset_tk(); 1163 } 1164 1165 static void sm_init_setup(sm_connection_t * sm_conn){ 1166 1167 // fill in sm setup 1168 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1169 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1170 1171 // query client for OOB data 1172 int have_oob_data = 0; 1173 if (sm_get_oob_data) { 1174 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1175 } 1176 1177 sm_pairing_packet_t * local_packet; 1178 if (IS_RESPONDER(sm_conn->sm_role)){ 1179 // slave 1180 local_packet = &setup->sm_s_pres; 1181 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1182 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1183 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1184 } else { 1185 // master 1186 local_packet = &setup->sm_m_preq; 1187 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1188 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1189 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1190 1191 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1192 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1193 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1194 } 1195 1196 uint8_t auth_req = sm_auth_req; 1197 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1198 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1199 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1200 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1201 } 1202 1203 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1204 1205 sm_pairing_packet_t * remote_packet; 1206 int remote_key_request; 1207 if (IS_RESPONDER(sm_conn->sm_role)){ 1208 // slave / responder 1209 remote_packet = &setup->sm_m_preq; 1210 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1211 } else { 1212 // master / initiator 1213 remote_packet = &setup->sm_s_pres; 1214 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1215 } 1216 1217 // check key size 1218 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1219 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1220 1221 // decide on STK generation method 1222 sm_setup_tk(); 1223 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1224 1225 // check if STK generation method is acceptable by client 1226 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1227 1228 // identical to responder 1229 sm_setup_key_distribution(remote_key_request); 1230 1231 // JUST WORKS doens't provide authentication 1232 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1233 1234 return 0; 1235 } 1236 1237 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1238 1239 // cache and reset context 1240 int matched_device_id = sm_address_resolution_test; 1241 address_resolution_mode_t mode = sm_address_resolution_mode; 1242 void * context = sm_address_resolution_context; 1243 1244 // reset context 1245 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1246 sm_address_resolution_context = NULL; 1247 sm_address_resolution_test = -1; 1248 hci_con_handle_t con_handle = 0; 1249 1250 sm_connection_t * sm_connection; 1251 #ifdef ENABLE_LE_CENTRAL 1252 sm_key_t ltk; 1253 #endif 1254 switch (mode){ 1255 case ADDRESS_RESOLUTION_GENERAL: 1256 break; 1257 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1258 sm_connection = (sm_connection_t *) context; 1259 con_handle = sm_connection->sm_handle; 1260 switch (event){ 1261 case ADDRESS_RESOLUTION_SUCEEDED: 1262 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1263 sm_connection->sm_le_db_index = matched_device_id; 1264 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1265 #ifdef ENABLE_LE_CENTRAL 1266 if (sm_connection->sm_role) break; 1267 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1268 sm_connection->sm_security_request_received = 0; 1269 sm_connection->sm_bonding_requested = 0; 1270 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1271 if (!sm_is_null_key(ltk)){ 1272 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1273 } else { 1274 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1275 } 1276 #endif 1277 break; 1278 case ADDRESS_RESOLUTION_FAILED: 1279 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1280 #ifdef ENABLE_LE_CENTRAL 1281 if (sm_connection->sm_role) break; 1282 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1283 sm_connection->sm_security_request_received = 0; 1284 sm_connection->sm_bonding_requested = 0; 1285 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1286 #endif 1287 break; 1288 } 1289 break; 1290 default: 1291 break; 1292 } 1293 1294 switch (event){ 1295 case ADDRESS_RESOLUTION_SUCEEDED: 1296 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1297 break; 1298 case ADDRESS_RESOLUTION_FAILED: 1299 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1300 break; 1301 } 1302 } 1303 1304 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1305 1306 int le_db_index = -1; 1307 1308 // lookup device based on IRK 1309 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1310 int i; 1311 for (i=0; i < le_device_db_count(); i++){ 1312 sm_key_t irk; 1313 bd_addr_t address; 1314 int address_type; 1315 le_device_db_info(i, &address_type, address, irk); 1316 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1317 log_info("sm: device found for IRK, updating"); 1318 le_db_index = i; 1319 break; 1320 } 1321 } 1322 } 1323 1324 // if not found, lookup via public address if possible 1325 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1326 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1327 int i; 1328 for (i=0; i < le_device_db_count(); i++){ 1329 bd_addr_t address; 1330 int address_type; 1331 le_device_db_info(i, &address_type, address, NULL); 1332 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1333 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1334 log_info("sm: device found for public address, updating"); 1335 le_db_index = i; 1336 break; 1337 } 1338 } 1339 } 1340 1341 // if not found, add to db 1342 if (le_db_index < 0) { 1343 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1344 } 1345 1346 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1347 1348 if (le_db_index >= 0){ 1349 1350 #ifdef ENABLE_LE_SIGNED_WRITE 1351 // store local CSRK 1352 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1353 log_info("sm: store local CSRK"); 1354 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1355 le_device_db_local_counter_set(le_db_index, 0); 1356 } 1357 1358 // store remote CSRK 1359 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1360 log_info("sm: store remote CSRK"); 1361 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1362 le_device_db_remote_counter_set(le_db_index, 0); 1363 } 1364 #endif 1365 // store encryption information for secure connections: LTK generated by ECDH 1366 if (setup->sm_use_secure_connections){ 1367 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1368 uint8_t zero_rand[8]; 1369 memset(zero_rand, 0, 8); 1370 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1371 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1372 } 1373 1374 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1375 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1376 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1377 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1378 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1379 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1380 1381 } 1382 } 1383 1384 // keep le_db_index 1385 sm_conn->sm_le_db_index = le_db_index; 1386 } 1387 1388 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1389 setup->sm_pairing_failed_reason = reason; 1390 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1391 } 1392 1393 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1394 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1395 } 1396 1397 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1398 1399 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1400 static int sm_passkey_used(stk_generation_method_t method); 1401 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1402 1403 static void sm_log_ec_keypair(void){ 1404 log_info("Elliptic curve: X"); 1405 log_info_hexdump(&ec_q[0],32); 1406 log_info("Elliptic curve: Y"); 1407 log_info_hexdump(&ec_q[32],32); 1408 } 1409 1410 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1411 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1412 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1413 } else { 1414 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1415 } 1416 } 1417 1418 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1419 if (IS_RESPONDER(sm_conn->sm_role)){ 1420 // Responder 1421 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1422 } else { 1423 // Initiator role 1424 switch (setup->sm_stk_generation_method){ 1425 case JUST_WORKS: 1426 sm_sc_prepare_dhkey_check(sm_conn); 1427 break; 1428 1429 case NK_BOTH_INPUT: 1430 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1431 break; 1432 case PK_INIT_INPUT: 1433 case PK_RESP_INPUT: 1434 case OK_BOTH_INPUT: 1435 if (setup->sm_passkey_bit < 20) { 1436 sm_sc_start_calculating_local_confirm(sm_conn); 1437 } else { 1438 sm_sc_prepare_dhkey_check(sm_conn); 1439 } 1440 break; 1441 case OOB: 1442 // TODO: implement SC OOB 1443 break; 1444 } 1445 } 1446 } 1447 1448 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1449 return sm_cmac_sc_buffer[offset]; 1450 } 1451 1452 static void sm_sc_cmac_done(uint8_t * hash){ 1453 log_info("sm_sc_cmac_done: "); 1454 log_info_hexdump(hash, 16); 1455 1456 sm_connection_t * sm_conn = sm_cmac_connection; 1457 sm_cmac_connection = NULL; 1458 link_key_type_t link_key_type; 1459 1460 switch (sm_conn->sm_engine_state){ 1461 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1462 memcpy(setup->sm_local_confirm, hash, 16); 1463 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1464 break; 1465 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1466 // check 1467 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1468 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1469 break; 1470 } 1471 sm_sc_state_after_receiving_random(sm_conn); 1472 break; 1473 case SM_SC_W4_CALCULATE_G2: { 1474 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1475 big_endian_store_32(setup->sm_tk, 12, vab); 1476 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1477 sm_trigger_user_response(sm_conn); 1478 break; 1479 } 1480 case SM_SC_W4_CALCULATE_F5_SALT: 1481 memcpy(setup->sm_t, hash, 16); 1482 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1483 break; 1484 case SM_SC_W4_CALCULATE_F5_MACKEY: 1485 memcpy(setup->sm_mackey, hash, 16); 1486 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1487 break; 1488 case SM_SC_W4_CALCULATE_F5_LTK: 1489 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1490 // Errata Service Release to the Bluetooth Specification: ESR09 1491 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1492 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1493 memcpy(setup->sm_ltk, hash, 16); 1494 memcpy(setup->sm_local_ltk, hash, 16); 1495 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1496 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1497 break; 1498 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1499 memcpy(setup->sm_local_dhkey_check, hash, 16); 1500 if (IS_RESPONDER(sm_conn->sm_role)){ 1501 // responder 1502 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1503 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1504 } else { 1505 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1506 } 1507 } else { 1508 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1509 } 1510 break; 1511 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1512 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1513 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1514 break; 1515 } 1516 if (IS_RESPONDER(sm_conn->sm_role)){ 1517 // responder 1518 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1519 } else { 1520 // initiator 1521 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1522 } 1523 break; 1524 case SM_SC_W4_CALCULATE_H6_ILK: 1525 memcpy(setup->sm_t, hash, 16); 1526 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1527 break; 1528 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1529 #ifdef ENABLE_CLASSIC 1530 reverse_128(hash, setup->sm_t); 1531 link_key_type = sm_conn->sm_connection_authenticated ? 1532 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1533 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1534 if (IS_RESPONDER(sm_conn->sm_role)){ 1535 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1536 } else { 1537 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1538 } 1539 #endif 1540 if (IS_RESPONDER(sm_conn->sm_role)){ 1541 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1542 } else { 1543 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1544 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1545 } 1546 sm_done_for_handle(sm_conn->sm_handle); 1547 break; 1548 default: 1549 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1550 break; 1551 } 1552 sm_run(); 1553 } 1554 1555 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){ 1556 const uint16_t message_len = 65; 1557 sm_cmac_connection = sm_conn; 1558 memcpy(sm_cmac_sc_buffer, u, 32); 1559 memcpy(sm_cmac_sc_buffer+32, v, 32); 1560 sm_cmac_sc_buffer[64] = z; 1561 log_info("f4 key"); 1562 log_info_hexdump(x, 16); 1563 log_info("f4 message"); 1564 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1565 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1566 } 1567 1568 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1569 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1570 static const uint8_t f5_length[] = { 0x01, 0x00}; 1571 1572 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1573 memset(dhkey, 0, 32); 1574 #ifdef USE_MICROECC_FOR_ECDH 1575 #if uECC_SUPPORTS_secp256r1 1576 // standard version 1577 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1()); 1578 #else 1579 // static version 1580 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1581 #endif 1582 #endif 1583 log_info("dhkey"); 1584 log_info_hexdump(dhkey, 32); 1585 } 1586 1587 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1588 // calculate DHKEY 1589 sm_key256_t dhkey; 1590 sm_sc_calculate_dhkey(dhkey); 1591 1592 // calculate salt for f5 1593 const uint16_t message_len = 32; 1594 sm_cmac_connection = sm_conn; 1595 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1596 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1597 } 1598 1599 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){ 1600 const uint16_t message_len = 53; 1601 sm_cmac_connection = sm_conn; 1602 1603 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1604 sm_cmac_sc_buffer[0] = 0; 1605 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1606 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1607 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1608 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1609 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1610 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1611 log_info("f5 key"); 1612 log_info_hexdump(t, 16); 1613 log_info("f5 message for MacKey"); 1614 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1615 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1616 } 1617 1618 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1619 sm_key56_t bd_addr_master, bd_addr_slave; 1620 bd_addr_master[0] = setup->sm_m_addr_type; 1621 bd_addr_slave[0] = setup->sm_s_addr_type; 1622 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1623 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1624 if (IS_RESPONDER(sm_conn->sm_role)){ 1625 // responder 1626 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1627 } else { 1628 // initiator 1629 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1630 } 1631 } 1632 1633 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1634 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1635 const uint16_t message_len = 53; 1636 sm_cmac_connection = sm_conn; 1637 sm_cmac_sc_buffer[0] = 1; 1638 // 1..52 setup before 1639 log_info("f5 key"); 1640 log_info_hexdump(t, 16); 1641 log_info("f5 message for LTK"); 1642 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1643 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1644 } 1645 1646 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1647 f5_ltk(sm_conn, setup->sm_t); 1648 } 1649 1650 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){ 1651 const uint16_t message_len = 65; 1652 sm_cmac_connection = sm_conn; 1653 memcpy(sm_cmac_sc_buffer, n1, 16); 1654 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1655 memcpy(sm_cmac_sc_buffer+32, r, 16); 1656 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1657 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1658 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1659 log_info("f6 key"); 1660 log_info_hexdump(w, 16); 1661 log_info("f6 message"); 1662 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1663 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1664 } 1665 1666 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1667 // - U is 256 bits 1668 // - V is 256 bits 1669 // - X is 128 bits 1670 // - Y is 128 bits 1671 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){ 1672 const uint16_t message_len = 80; 1673 sm_cmac_connection = sm_conn; 1674 memcpy(sm_cmac_sc_buffer, u, 32); 1675 memcpy(sm_cmac_sc_buffer+32, v, 32); 1676 memcpy(sm_cmac_sc_buffer+64, y, 16); 1677 log_info("g2 key"); 1678 log_info_hexdump(x, 16); 1679 log_info("g2 message"); 1680 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1681 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1682 } 1683 1684 static void g2_calculate(sm_connection_t * sm_conn) { 1685 // calc Va if numeric comparison 1686 if (IS_RESPONDER(sm_conn->sm_role)){ 1687 // responder 1688 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1689 } else { 1690 // initiator 1691 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1692 } 1693 } 1694 1695 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1696 uint8_t z = 0; 1697 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1698 // some form of passkey 1699 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1700 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1701 setup->sm_passkey_bit++; 1702 } 1703 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1704 } 1705 1706 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1707 uint8_t z = 0; 1708 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1709 // some form of passkey 1710 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1711 // sm_passkey_bit was increased before sending confirm value 1712 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1713 } 1714 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1715 } 1716 1717 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1718 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1719 } 1720 1721 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1722 // calculate DHKCheck 1723 sm_key56_t bd_addr_master, bd_addr_slave; 1724 bd_addr_master[0] = setup->sm_m_addr_type; 1725 bd_addr_slave[0] = setup->sm_s_addr_type; 1726 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1727 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1728 uint8_t iocap_a[3]; 1729 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1730 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1731 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1732 uint8_t iocap_b[3]; 1733 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1734 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1735 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1736 if (IS_RESPONDER(sm_conn->sm_role)){ 1737 // responder 1738 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); 1739 } else { 1740 // initiator 1741 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); 1742 } 1743 } 1744 1745 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1746 // validate E = f6() 1747 sm_key56_t bd_addr_master, bd_addr_slave; 1748 bd_addr_master[0] = setup->sm_m_addr_type; 1749 bd_addr_slave[0] = setup->sm_s_addr_type; 1750 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1751 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1752 1753 uint8_t iocap_a[3]; 1754 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1755 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1756 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1757 uint8_t iocap_b[3]; 1758 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1759 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1760 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1761 if (IS_RESPONDER(sm_conn->sm_role)){ 1762 // responder 1763 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); 1764 } else { 1765 // initiator 1766 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); 1767 } 1768 } 1769 1770 1771 // 1772 // Link Key Conversion Function h6 1773 // 1774 // h6(W, keyID) = AES-CMACW(keyID) 1775 // - W is 128 bits 1776 // - keyID is 32 bits 1777 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1778 const uint16_t message_len = 4; 1779 sm_cmac_connection = sm_conn; 1780 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1781 log_info("h6 key"); 1782 log_info_hexdump(w, 16); 1783 log_info("h6 message"); 1784 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1785 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1786 } 1787 1788 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1789 // Errata Service Release to the Bluetooth Specification: ESR09 1790 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1791 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1792 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1793 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1794 } 1795 1796 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1797 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1798 } 1799 1800 #endif 1801 1802 // key management legacy connections: 1803 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1804 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1805 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1806 // - responder reconnects: responder uses LTK receveived from master 1807 1808 // key management secure connections: 1809 // - both devices store same LTK from ECDH key exchange. 1810 1811 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1812 static void sm_load_security_info(sm_connection_t * sm_connection){ 1813 int encryption_key_size; 1814 int authenticated; 1815 int authorized; 1816 1817 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1818 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1819 &encryption_key_size, &authenticated, &authorized); 1820 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1821 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1822 sm_connection->sm_connection_authenticated = authenticated; 1823 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1824 } 1825 #endif 1826 1827 #ifdef ENABLE_LE_PERIPHERAL 1828 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1829 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1830 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1831 // re-establish used key encryption size 1832 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1833 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1834 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1835 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1836 log_info("sm: received ltk request with key size %u, authenticated %u", 1837 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1838 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1839 } 1840 #endif 1841 1842 static void sm_run(void){ 1843 1844 btstack_linked_list_iterator_t it; 1845 1846 // assert that stack has already bootet 1847 if (hci_get_state() != HCI_STATE_WORKING) return; 1848 1849 // assert that we can send at least commands 1850 if (!hci_can_send_command_packet_now()) return; 1851 1852 // 1853 // non-connection related behaviour 1854 // 1855 1856 // distributed key generation 1857 switch (dkg_state){ 1858 case DKG_CALC_IRK: 1859 // already busy? 1860 if (sm_aes128_state == SM_AES128_IDLE) { 1861 // IRK = d1(IR, 1, 0) 1862 sm_key_t d1_prime; 1863 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1864 dkg_next_state(); 1865 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1866 return; 1867 } 1868 break; 1869 case DKG_CALC_DHK: 1870 // already busy? 1871 if (sm_aes128_state == SM_AES128_IDLE) { 1872 // DHK = d1(IR, 3, 0) 1873 sm_key_t d1_prime; 1874 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1875 dkg_next_state(); 1876 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1877 return; 1878 } 1879 break; 1880 default: 1881 break; 1882 } 1883 1884 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1885 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1886 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 1887 sm_random_start(NULL); 1888 #else 1889 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1890 hci_send_cmd(&hci_le_read_local_p256_public_key); 1891 #endif 1892 return; 1893 } 1894 #endif 1895 1896 // random address updates 1897 switch (rau_state){ 1898 case RAU_GET_RANDOM: 1899 rau_next_state(); 1900 sm_random_start(NULL); 1901 return; 1902 case RAU_GET_ENC: 1903 // already busy? 1904 if (sm_aes128_state == SM_AES128_IDLE) { 1905 sm_key_t r_prime; 1906 sm_ah_r_prime(sm_random_address, r_prime); 1907 rau_next_state(); 1908 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1909 return; 1910 } 1911 break; 1912 case RAU_SET_ADDRESS: 1913 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1914 rau_state = RAU_IDLE; 1915 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1916 return; 1917 default: 1918 break; 1919 } 1920 1921 #ifdef ENABLE_CMAC_ENGINE 1922 // CMAC 1923 switch (sm_cmac_state){ 1924 case CMAC_CALC_SUBKEYS: 1925 case CMAC_CALC_MI: 1926 case CMAC_CALC_MLAST: 1927 // already busy? 1928 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1929 sm_cmac_handle_aes_engine_ready(); 1930 return; 1931 default: 1932 break; 1933 } 1934 #endif 1935 1936 // CSRK Lookup 1937 // -- if csrk lookup ready, find connection that require csrk lookup 1938 if (sm_address_resolution_idle()){ 1939 hci_connections_get_iterator(&it); 1940 while(btstack_linked_list_iterator_has_next(&it)){ 1941 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1942 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1943 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1944 // and start lookup 1945 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); 1946 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1947 break; 1948 } 1949 } 1950 } 1951 1952 // -- if csrk lookup ready, resolved addresses for received addresses 1953 if (sm_address_resolution_idle()) { 1954 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1955 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1956 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1957 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1958 btstack_memory_sm_lookup_entry_free(entry); 1959 } 1960 } 1961 1962 // -- Continue with CSRK device lookup by public or resolvable private address 1963 if (!sm_address_resolution_idle()){ 1964 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1965 while (sm_address_resolution_test < le_device_db_count()){ 1966 int addr_type; 1967 bd_addr_t addr; 1968 sm_key_t irk; 1969 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1970 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1971 1972 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1973 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1974 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1975 break; 1976 } 1977 1978 if (sm_address_resolution_addr_type == 0){ 1979 sm_address_resolution_test++; 1980 continue; 1981 } 1982 1983 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1984 1985 log_info("LE Device Lookup: calculate AH"); 1986 log_info_key("IRK", irk); 1987 1988 sm_key_t r_prime; 1989 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1990 sm_address_resolution_ah_calculation_active = 1; 1991 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1992 return; 1993 } 1994 1995 if (sm_address_resolution_test >= le_device_db_count()){ 1996 log_info("LE Device Lookup: not found"); 1997 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1998 } 1999 } 2000 2001 // handle basic actions that don't requires the full context 2002 hci_connections_get_iterator(&it); 2003 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2004 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2005 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2006 switch(sm_connection->sm_engine_state){ 2007 // responder side 2008 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2009 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2010 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2011 return; 2012 2013 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2014 case SM_SC_RECEIVED_LTK_REQUEST: 2015 switch (sm_connection->sm_irk_lookup_state){ 2016 case IRK_LOOKUP_FAILED: 2017 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2018 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2019 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2020 return; 2021 default: 2022 break; 2023 } 2024 break; 2025 #endif 2026 default: 2027 break; 2028 } 2029 } 2030 2031 // 2032 // active connection handling 2033 // -- use loop to handle next connection if lock on setup context is released 2034 2035 while (1) { 2036 2037 // Find connections that requires setup context and make active if no other is locked 2038 hci_connections_get_iterator(&it); 2039 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2040 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2041 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2042 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2043 int done = 1; 2044 int err; 2045 UNUSED(err); 2046 switch (sm_connection->sm_engine_state) { 2047 #ifdef ENABLE_LE_PERIPHERAL 2048 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2049 // send packet if possible, 2050 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2051 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2052 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2053 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2054 } else { 2055 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2056 } 2057 // don't lock sxetup context yet 2058 done = 0; 2059 break; 2060 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2061 sm_reset_setup(); 2062 sm_init_setup(sm_connection); 2063 // recover pairing request 2064 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2065 err = sm_stk_generation_init(sm_connection); 2066 if (err){ 2067 setup->sm_pairing_failed_reason = err; 2068 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2069 break; 2070 } 2071 sm_timeout_start(sm_connection); 2072 // generate random number first, if we need to show passkey 2073 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2074 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2075 break; 2076 } 2077 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2078 break; 2079 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2080 sm_reset_setup(); 2081 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2082 break; 2083 #endif 2084 #ifdef ENABLE_LE_CENTRAL 2085 case SM_INITIATOR_PH0_HAS_LTK: 2086 sm_reset_setup(); 2087 sm_load_security_info(sm_connection); 2088 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2089 break; 2090 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2091 sm_reset_setup(); 2092 sm_init_setup(sm_connection); 2093 sm_timeout_start(sm_connection); 2094 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2095 break; 2096 #endif 2097 2098 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2099 case SM_SC_RECEIVED_LTK_REQUEST: 2100 switch (sm_connection->sm_irk_lookup_state){ 2101 case IRK_LOOKUP_SUCCEEDED: 2102 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2103 // start using context by loading security info 2104 sm_reset_setup(); 2105 sm_load_security_info(sm_connection); 2106 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2107 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2108 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2109 break; 2110 } 2111 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2112 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2113 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2114 // don't lock setup context yet 2115 return; 2116 default: 2117 // just wait until IRK lookup is completed 2118 // don't lock setup context yet 2119 done = 0; 2120 break; 2121 } 2122 break; 2123 #endif 2124 default: 2125 done = 0; 2126 break; 2127 } 2128 if (done){ 2129 sm_active_connection_handle = sm_connection->sm_handle; 2130 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); 2131 } 2132 } 2133 2134 // 2135 // active connection handling 2136 // 2137 2138 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2139 2140 // assert that we could send a SM PDU - not needed for all of the following 2141 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2142 log_info("cannot send now, requesting can send now event"); 2143 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2144 return; 2145 } 2146 2147 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2148 if (!connection) { 2149 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2150 return; 2151 } 2152 2153 // send keypress notifications 2154 if (setup->sm_keypress_notification != 0xff){ 2155 uint8_t buffer[2]; 2156 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2157 buffer[1] = setup->sm_keypress_notification; 2158 setup->sm_keypress_notification = 0xff; 2159 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2160 return; 2161 } 2162 2163 sm_key_t plaintext; 2164 int key_distribution_flags; 2165 UNUSED(key_distribution_flags); 2166 2167 log_info("sm_run: state %u", connection->sm_engine_state); 2168 2169 switch (connection->sm_engine_state){ 2170 2171 // general 2172 case SM_GENERAL_SEND_PAIRING_FAILED: { 2173 uint8_t buffer[2]; 2174 buffer[0] = SM_CODE_PAIRING_FAILED; 2175 buffer[1] = setup->sm_pairing_failed_reason; 2176 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2177 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2178 sm_done_for_handle(connection->sm_handle); 2179 break; 2180 } 2181 2182 // responding state 2183 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2184 case SM_SC_W2_GET_RANDOM_A: 2185 sm_random_start(connection); 2186 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2187 break; 2188 case SM_SC_W2_GET_RANDOM_B: 2189 sm_random_start(connection); 2190 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2191 break; 2192 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2193 if (!sm_cmac_ready()) break; 2194 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2195 sm_sc_calculate_local_confirm(connection); 2196 break; 2197 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2198 if (!sm_cmac_ready()) break; 2199 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2200 sm_sc_calculate_remote_confirm(connection); 2201 break; 2202 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2203 if (!sm_cmac_ready()) break; 2204 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2205 sm_sc_calculate_f6_for_dhkey_check(connection); 2206 break; 2207 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2208 if (!sm_cmac_ready()) break; 2209 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2210 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2211 break; 2212 case SM_SC_W2_CALCULATE_F5_SALT: 2213 if (!sm_cmac_ready()) break; 2214 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2215 f5_calculate_salt(connection); 2216 break; 2217 case SM_SC_W2_CALCULATE_F5_MACKEY: 2218 if (!sm_cmac_ready()) break; 2219 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2220 f5_calculate_mackey(connection); 2221 break; 2222 case SM_SC_W2_CALCULATE_F5_LTK: 2223 if (!sm_cmac_ready()) break; 2224 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2225 f5_calculate_ltk(connection); 2226 break; 2227 case SM_SC_W2_CALCULATE_G2: 2228 if (!sm_cmac_ready()) break; 2229 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2230 g2_calculate(connection); 2231 break; 2232 case SM_SC_W2_CALCULATE_H6_ILK: 2233 if (!sm_cmac_ready()) break; 2234 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2235 h6_calculate_ilk(connection); 2236 break; 2237 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2238 if (!sm_cmac_ready()) break; 2239 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2240 h6_calculate_br_edr_link_key(connection); 2241 break; 2242 #endif 2243 2244 #ifdef ENABLE_LE_CENTRAL 2245 // initiator side 2246 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2247 sm_key_t peer_ltk_flipped; 2248 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2249 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2250 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2251 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2252 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2253 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2254 return; 2255 } 2256 2257 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2258 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2259 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2260 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2261 sm_timeout_reset(connection); 2262 break; 2263 #endif 2264 2265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2266 2267 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2268 uint8_t buffer[65]; 2269 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2270 // 2271 reverse_256(&ec_q[0], &buffer[1]); 2272 reverse_256(&ec_q[32], &buffer[33]); 2273 2274 // stk generation method 2275 // passkey entry: notify app to show passkey or to request passkey 2276 switch (setup->sm_stk_generation_method){ 2277 case JUST_WORKS: 2278 case NK_BOTH_INPUT: 2279 if (IS_RESPONDER(connection->sm_role)){ 2280 // responder 2281 sm_sc_start_calculating_local_confirm(connection); 2282 } else { 2283 // initiator 2284 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2285 } 2286 break; 2287 case PK_INIT_INPUT: 2288 case PK_RESP_INPUT: 2289 case OK_BOTH_INPUT: 2290 // use random TK for display 2291 memcpy(setup->sm_ra, setup->sm_tk, 16); 2292 memcpy(setup->sm_rb, setup->sm_tk, 16); 2293 setup->sm_passkey_bit = 0; 2294 2295 if (IS_RESPONDER(connection->sm_role)){ 2296 // responder 2297 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2298 } else { 2299 // initiator 2300 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2301 } 2302 sm_trigger_user_response(connection); 2303 break; 2304 case OOB: 2305 // TODO: implement SC OOB 2306 break; 2307 } 2308 2309 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2310 sm_timeout_reset(connection); 2311 break; 2312 } 2313 case SM_SC_SEND_CONFIRMATION: { 2314 uint8_t buffer[17]; 2315 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2316 reverse_128(setup->sm_local_confirm, &buffer[1]); 2317 if (IS_RESPONDER(connection->sm_role)){ 2318 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2319 } else { 2320 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2321 } 2322 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2323 sm_timeout_reset(connection); 2324 break; 2325 } 2326 case SM_SC_SEND_PAIRING_RANDOM: { 2327 uint8_t buffer[17]; 2328 buffer[0] = SM_CODE_PAIRING_RANDOM; 2329 reverse_128(setup->sm_local_nonce, &buffer[1]); 2330 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2331 if (IS_RESPONDER(connection->sm_role)){ 2332 // responder 2333 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2334 } else { 2335 // initiator 2336 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2337 } 2338 } else { 2339 if (IS_RESPONDER(connection->sm_role)){ 2340 // responder 2341 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2342 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2343 } else { 2344 sm_sc_prepare_dhkey_check(connection); 2345 } 2346 } else { 2347 // initiator 2348 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2349 } 2350 } 2351 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2352 sm_timeout_reset(connection); 2353 break; 2354 } 2355 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2356 uint8_t buffer[17]; 2357 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2358 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2359 2360 if (IS_RESPONDER(connection->sm_role)){ 2361 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2362 } else { 2363 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2364 } 2365 2366 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2367 sm_timeout_reset(connection); 2368 break; 2369 } 2370 2371 #endif 2372 2373 #ifdef ENABLE_LE_PERIPHERAL 2374 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2375 // echo initiator for now 2376 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2377 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2378 2379 if (setup->sm_use_secure_connections){ 2380 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2381 // skip LTK/EDIV for SC 2382 log_info("sm: dropping encryption information flag"); 2383 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2384 } else { 2385 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2386 } 2387 2388 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); 2389 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); 2390 // update key distribution after ENC was dropped 2391 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2392 2393 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2394 sm_timeout_reset(connection); 2395 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2396 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2397 sm_trigger_user_response(connection); 2398 } 2399 return; 2400 #endif 2401 2402 case SM_PH2_SEND_PAIRING_RANDOM: { 2403 uint8_t buffer[17]; 2404 buffer[0] = SM_CODE_PAIRING_RANDOM; 2405 reverse_128(setup->sm_local_random, &buffer[1]); 2406 if (IS_RESPONDER(connection->sm_role)){ 2407 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2408 } else { 2409 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2410 } 2411 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2412 sm_timeout_reset(connection); 2413 break; 2414 } 2415 2416 case SM_PH2_GET_RANDOM_TK: 2417 case SM_PH2_C1_GET_RANDOM_A: 2418 case SM_PH2_C1_GET_RANDOM_B: 2419 case SM_PH3_GET_RANDOM: 2420 case SM_PH3_GET_DIV: 2421 sm_next_responding_state(connection); 2422 sm_random_start(connection); 2423 return; 2424 2425 case SM_PH2_C1_GET_ENC_B: 2426 case SM_PH2_C1_GET_ENC_D: 2427 // already busy? 2428 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2429 sm_next_responding_state(connection); 2430 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2431 return; 2432 2433 case SM_PH3_LTK_GET_ENC: 2434 case SM_RESPONDER_PH4_LTK_GET_ENC: 2435 // already busy? 2436 if (sm_aes128_state == SM_AES128_IDLE) { 2437 sm_key_t d_prime; 2438 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2439 sm_next_responding_state(connection); 2440 sm_aes128_start(sm_persistent_er, d_prime, connection); 2441 return; 2442 } 2443 break; 2444 2445 case SM_PH3_CSRK_GET_ENC: 2446 // already busy? 2447 if (sm_aes128_state == SM_AES128_IDLE) { 2448 sm_key_t d_prime; 2449 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2450 sm_next_responding_state(connection); 2451 sm_aes128_start(sm_persistent_er, d_prime, connection); 2452 return; 2453 } 2454 break; 2455 2456 case SM_PH2_C1_GET_ENC_C: 2457 // already busy? 2458 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2459 // calculate m_confirm using aes128 engine - step 1 2460 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, plaintext); 2461 sm_next_responding_state(connection); 2462 sm_aes128_start(setup->sm_tk, plaintext, connection); 2463 break; 2464 case SM_PH2_C1_GET_ENC_A: 2465 // already busy? 2466 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2467 // calculate confirm using aes128 engine - step 1 2468 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, plaintext); 2469 sm_next_responding_state(connection); 2470 sm_aes128_start(setup->sm_tk, plaintext, connection); 2471 break; 2472 case SM_PH2_CALC_STK: 2473 // already busy? 2474 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2475 // calculate STK 2476 if (IS_RESPONDER(connection->sm_role)){ 2477 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2478 } else { 2479 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2480 } 2481 sm_next_responding_state(connection); 2482 sm_aes128_start(setup->sm_tk, plaintext, connection); 2483 break; 2484 case SM_PH3_Y_GET_ENC: 2485 // already busy? 2486 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2487 // PH3B2 - calculate Y from - enc 2488 // Y = dm(DHK, Rand) 2489 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2490 sm_next_responding_state(connection); 2491 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2492 return; 2493 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2494 uint8_t buffer[17]; 2495 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2496 reverse_128(setup->sm_local_confirm, &buffer[1]); 2497 if (IS_RESPONDER(connection->sm_role)){ 2498 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2499 } else { 2500 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2501 } 2502 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2503 sm_timeout_reset(connection); 2504 return; 2505 } 2506 #ifdef ENABLE_LE_PERIPHERAL 2507 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2508 sm_key_t stk_flipped; 2509 reverse_128(setup->sm_ltk, stk_flipped); 2510 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2511 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2512 return; 2513 } 2514 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2515 sm_key_t ltk_flipped; 2516 reverse_128(setup->sm_ltk, ltk_flipped); 2517 connection->sm_engine_state = SM_RESPONDER_IDLE; 2518 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2519 return; 2520 } 2521 case SM_RESPONDER_PH4_Y_GET_ENC: 2522 // already busy? 2523 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2524 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2525 // Y = dm(DHK, Rand) 2526 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2527 sm_next_responding_state(connection); 2528 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2529 return; 2530 #endif 2531 #ifdef ENABLE_LE_CENTRAL 2532 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2533 sm_key_t stk_flipped; 2534 reverse_128(setup->sm_ltk, stk_flipped); 2535 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2536 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2537 return; 2538 } 2539 #endif 2540 2541 case SM_PH3_DISTRIBUTE_KEYS: 2542 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2543 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2544 uint8_t buffer[17]; 2545 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2546 reverse_128(setup->sm_ltk, &buffer[1]); 2547 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2548 sm_timeout_reset(connection); 2549 return; 2550 } 2551 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2552 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2553 uint8_t buffer[11]; 2554 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2555 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2556 reverse_64(setup->sm_local_rand, &buffer[3]); 2557 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2558 sm_timeout_reset(connection); 2559 return; 2560 } 2561 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2562 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2563 uint8_t buffer[17]; 2564 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2565 reverse_128(sm_persistent_irk, &buffer[1]); 2566 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2567 sm_timeout_reset(connection); 2568 return; 2569 } 2570 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2571 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2572 bd_addr_t local_address; 2573 uint8_t buffer[8]; 2574 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2575 gap_le_get_own_address(&buffer[1], local_address); 2576 reverse_bd_addr(local_address, &buffer[2]); 2577 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2578 sm_timeout_reset(connection); 2579 return; 2580 } 2581 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2582 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2583 2584 // hack to reproduce test runs 2585 if (test_use_fixed_local_csrk){ 2586 memset(setup->sm_local_csrk, 0xcc, 16); 2587 } 2588 2589 uint8_t buffer[17]; 2590 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2591 reverse_128(setup->sm_local_csrk, &buffer[1]); 2592 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2593 sm_timeout_reset(connection); 2594 return; 2595 } 2596 2597 // keys are sent 2598 if (IS_RESPONDER(connection->sm_role)){ 2599 // slave -> receive master keys if any 2600 if (sm_key_distribution_all_received(connection)){ 2601 sm_key_distribution_handle_all_received(connection); 2602 connection->sm_engine_state = SM_RESPONDER_IDLE; 2603 sm_done_for_handle(connection->sm_handle); 2604 } else { 2605 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2606 } 2607 } else { 2608 // master -> all done 2609 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2610 sm_done_for_handle(connection->sm_handle); 2611 } 2612 break; 2613 2614 default: 2615 break; 2616 } 2617 2618 // check again if active connection was released 2619 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2620 } 2621 } 2622 2623 // note: aes engine is ready as we just got the aes result 2624 static void sm_handle_encryption_result(uint8_t * data){ 2625 2626 sm_aes128_state = SM_AES128_IDLE; 2627 2628 if (sm_address_resolution_ah_calculation_active){ 2629 sm_address_resolution_ah_calculation_active = 0; 2630 // compare calulated address against connecting device 2631 uint8_t hash[3]; 2632 reverse_24(data, hash); 2633 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2634 log_info("LE Device Lookup: matched resolvable private address"); 2635 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2636 return; 2637 } 2638 // no match, try next 2639 sm_address_resolution_test++; 2640 return; 2641 } 2642 2643 switch (dkg_state){ 2644 case DKG_W4_IRK: 2645 reverse_128(data, sm_persistent_irk); 2646 log_info_key("irk", sm_persistent_irk); 2647 dkg_next_state(); 2648 return; 2649 case DKG_W4_DHK: 2650 reverse_128(data, sm_persistent_dhk); 2651 log_info_key("dhk", sm_persistent_dhk); 2652 dkg_next_state(); 2653 // SM Init Finished 2654 return; 2655 default: 2656 break; 2657 } 2658 2659 switch (rau_state){ 2660 case RAU_W4_ENC: 2661 reverse_24(data, &sm_random_address[3]); 2662 rau_next_state(); 2663 return; 2664 default: 2665 break; 2666 } 2667 2668 #ifdef ENABLE_CMAC_ENGINE 2669 switch (sm_cmac_state){ 2670 case CMAC_W4_SUBKEYS: 2671 case CMAC_W4_MI: 2672 case CMAC_W4_MLAST: 2673 { 2674 sm_key_t t; 2675 reverse_128(data, t); 2676 sm_cmac_handle_encryption_result(t); 2677 } 2678 return; 2679 default: 2680 break; 2681 } 2682 #endif 2683 2684 // retrieve sm_connection provided to sm_aes128_start_encryption 2685 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2686 if (!connection) return; 2687 switch (connection->sm_engine_state){ 2688 case SM_PH2_C1_W4_ENC_A: 2689 case SM_PH2_C1_W4_ENC_C: 2690 { 2691 sm_key_t t2; 2692 reverse_128(data, t2); 2693 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2694 } 2695 sm_next_responding_state(connection); 2696 return; 2697 case SM_PH2_C1_W4_ENC_B: 2698 reverse_128(data, setup->sm_local_confirm); 2699 log_info_key("c1!", setup->sm_local_confirm); 2700 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2701 return; 2702 case SM_PH2_C1_W4_ENC_D: 2703 { 2704 sm_key_t peer_confirm_test; 2705 reverse_128(data, peer_confirm_test); 2706 log_info_key("c1!", peer_confirm_test); 2707 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2708 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2709 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2710 return; 2711 } 2712 if (IS_RESPONDER(connection->sm_role)){ 2713 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2714 } else { 2715 connection->sm_engine_state = SM_PH2_CALC_STK; 2716 } 2717 } 2718 return; 2719 case SM_PH2_W4_STK: 2720 reverse_128(data, setup->sm_ltk); 2721 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2722 log_info_key("stk", setup->sm_ltk); 2723 if (IS_RESPONDER(connection->sm_role)){ 2724 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2725 } else { 2726 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2727 } 2728 return; 2729 case SM_PH3_Y_W4_ENC:{ 2730 sm_key_t y128; 2731 reverse_128(data, y128); 2732 setup->sm_local_y = big_endian_read_16(y128, 14); 2733 log_info_hex16("y", setup->sm_local_y); 2734 // PH3B3 - calculate EDIV 2735 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2736 log_info_hex16("ediv", setup->sm_local_ediv); 2737 // PH3B4 - calculate LTK - enc 2738 // LTK = d1(ER, DIV, 0)) 2739 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2740 return; 2741 } 2742 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2743 sm_key_t y128; 2744 reverse_128(data, y128); 2745 setup->sm_local_y = big_endian_read_16(y128, 14); 2746 log_info_hex16("y", setup->sm_local_y); 2747 2748 // PH3B3 - calculate DIV 2749 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2750 log_info_hex16("ediv", setup->sm_local_ediv); 2751 // PH3B4 - calculate LTK - enc 2752 // LTK = d1(ER, DIV, 0)) 2753 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2754 return; 2755 } 2756 case SM_PH3_LTK_W4_ENC: 2757 reverse_128(data, setup->sm_ltk); 2758 log_info_key("ltk", setup->sm_ltk); 2759 // calc CSRK next 2760 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2761 return; 2762 case SM_PH3_CSRK_W4_ENC: 2763 reverse_128(data, setup->sm_local_csrk); 2764 log_info_key("csrk", setup->sm_local_csrk); 2765 if (setup->sm_key_distribution_send_set){ 2766 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2767 } else { 2768 // no keys to send, just continue 2769 if (IS_RESPONDER(connection->sm_role)){ 2770 // slave -> receive master keys 2771 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2772 } else { 2773 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2774 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2775 } else { 2776 // master -> all done 2777 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2778 sm_done_for_handle(connection->sm_handle); 2779 } 2780 } 2781 } 2782 return; 2783 #ifdef ENABLE_LE_PERIPHERAL 2784 case SM_RESPONDER_PH4_LTK_W4_ENC: 2785 reverse_128(data, setup->sm_ltk); 2786 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2787 log_info_key("ltk", setup->sm_ltk); 2788 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2789 return; 2790 #endif 2791 default: 2792 break; 2793 } 2794 } 2795 2796 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2797 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 2798 #if !defined(WICED_VERSION) 2799 // @return OK 2800 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2801 if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; 2802 int offset = setup->sm_passkey_bit; 2803 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2804 while (size) { 2805 *buffer++ = setup->sm_peer_q[offset++]; 2806 size--; 2807 } 2808 setup->sm_passkey_bit = offset; 2809 return 1; 2810 } 2811 #endif 2812 #endif 2813 #endif 2814 2815 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2816 static void sm_handle_random_result(uint8_t * data){ 2817 2818 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2819 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 2820 2821 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2822 int num_bytes = setup->sm_passkey_bit; 2823 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 2824 num_bytes += 8; 2825 setup->sm_passkey_bit = num_bytes; 2826 2827 if (num_bytes >= 64){ 2828 2829 // init pre-generated random data from sm_peer_q 2830 setup->sm_passkey_bit = 0; 2831 2832 // generate EC key 2833 #ifdef USE_MICROECC_FOR_ECDH 2834 #ifndef WICED_VERSION 2835 log_info("set uECC RNG for initial key generation with 64 random bytes"); 2836 // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it 2837 uECC_set_rng(&sm_generate_f_rng); 2838 #endif /* WICED_VERSION */ 2839 2840 #if uECC_SUPPORTS_secp256r1 2841 // standard version 2842 uECC_make_key(ec_q, ec_d, uECC_secp256r1()); 2843 2844 // disable RNG again, as returning no randmon data lets shared key generation fail 2845 log_info("disable uECC RNG in standard version after key generation"); 2846 uECC_set_rng(NULL); 2847 #else 2848 // static version 2849 uECC_make_key(ec_q, ec_d); 2850 #endif /* USE_MICROECC_FOR_ECDH */ 2851 2852 #endif /* USE_MICROECC_FOR_ECDH */ 2853 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2854 log_info("Elliptic curve: d"); 2855 log_info_hexdump(ec_d,32); 2856 sm_log_ec_keypair(); 2857 } 2858 } 2859 #endif 2860 #endif 2861 2862 switch (rau_state){ 2863 case RAU_W4_RANDOM: 2864 // non-resolvable vs. resolvable 2865 switch (gap_random_adress_type){ 2866 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2867 // resolvable: use random as prand and calc address hash 2868 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2869 memcpy(sm_random_address, data, 3); 2870 sm_random_address[0] &= 0x3f; 2871 sm_random_address[0] |= 0x40; 2872 rau_state = RAU_GET_ENC; 2873 break; 2874 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2875 default: 2876 // "The two most significant bits of the address shall be equal to ‘0’"" 2877 memcpy(sm_random_address, data, 6); 2878 sm_random_address[0] &= 0x3f; 2879 rau_state = RAU_SET_ADDRESS; 2880 break; 2881 } 2882 return; 2883 default: 2884 break; 2885 } 2886 2887 // retrieve sm_connection provided to sm_random_start 2888 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2889 if (!connection) return; 2890 switch (connection->sm_engine_state){ 2891 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2892 case SM_SC_W4_GET_RANDOM_A: 2893 memcpy(&setup->sm_local_nonce[0], data, 8); 2894 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2895 break; 2896 case SM_SC_W4_GET_RANDOM_B: 2897 memcpy(&setup->sm_local_nonce[8], data, 8); 2898 // initiator & jw/nc -> send pairing random 2899 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2900 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2901 break; 2902 } else { 2903 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2904 } 2905 break; 2906 #endif 2907 2908 case SM_PH2_W4_RANDOM_TK: 2909 { 2910 // map random to 0-999999 without speding much cycles on a modulus operation 2911 uint32_t tk = little_endian_read_32(data,0); 2912 tk = tk & 0xfffff; // 1048575 2913 if (tk >= 999999){ 2914 tk = tk - 999999; 2915 } 2916 sm_reset_tk(); 2917 big_endian_store_32(setup->sm_tk, 12, tk); 2918 if (IS_RESPONDER(connection->sm_role)){ 2919 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2920 } else { 2921 if (setup->sm_use_secure_connections){ 2922 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2923 } else { 2924 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2925 sm_trigger_user_response(connection); 2926 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2927 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2928 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2929 } 2930 } 2931 } 2932 return; 2933 } 2934 case SM_PH2_C1_W4_RANDOM_A: 2935 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2936 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2937 return; 2938 case SM_PH2_C1_W4_RANDOM_B: 2939 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2940 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2941 return; 2942 case SM_PH3_W4_RANDOM: 2943 reverse_64(data, setup->sm_local_rand); 2944 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2945 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2946 // no db for authenticated flag hack: store flag in bit 4 of LSB 2947 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2948 connection->sm_engine_state = SM_PH3_GET_DIV; 2949 return; 2950 case SM_PH3_W4_DIV: 2951 // use 16 bit from random value as div 2952 setup->sm_local_div = big_endian_read_16(data, 0); 2953 log_info_hex16("div", setup->sm_local_div); 2954 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2955 return; 2956 default: 2957 break; 2958 } 2959 } 2960 2961 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2962 2963 UNUSED(channel); 2964 UNUSED(size); 2965 2966 sm_connection_t * sm_conn; 2967 hci_con_handle_t con_handle; 2968 2969 switch (packet_type) { 2970 2971 case HCI_EVENT_PACKET: 2972 switch (hci_event_packet_get_type(packet)) { 2973 2974 case BTSTACK_EVENT_STATE: 2975 // bt stack activated, get started 2976 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2977 log_info("HCI Working!"); 2978 2979 // set local addr for le device db 2980 bd_addr_t local_bd_addr; 2981 gap_local_bd_addr(local_bd_addr); 2982 le_device_db_set_local_bd_addr(local_bd_addr); 2983 2984 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2985 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2986 if (!sm_have_ec_keypair){ 2987 setup->sm_passkey_bit = 0; 2988 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2989 } 2990 #endif 2991 // trigger Random Address generation if requested before 2992 switch (gap_random_adress_type){ 2993 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2994 rau_state = RAU_IDLE; 2995 break; 2996 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2997 rau_state = RAU_SET_ADDRESS; 2998 break; 2999 default: 3000 rau_state = RAU_GET_RANDOM; 3001 break; 3002 } 3003 sm_run(); 3004 } 3005 break; 3006 3007 case HCI_EVENT_LE_META: 3008 switch (packet[2]) { 3009 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3010 3011 log_info("sm: connected"); 3012 3013 if (packet[3]) return; // connection failed 3014 3015 con_handle = little_endian_read_16(packet, 4); 3016 sm_conn = sm_get_connection_for_handle(con_handle); 3017 if (!sm_conn) break; 3018 3019 sm_conn->sm_handle = con_handle; 3020 sm_conn->sm_role = packet[6]; 3021 sm_conn->sm_peer_addr_type = packet[7]; 3022 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3023 3024 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3025 3026 // reset security properties 3027 sm_conn->sm_connection_encrypted = 0; 3028 sm_conn->sm_connection_authenticated = 0; 3029 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3030 sm_conn->sm_le_db_index = -1; 3031 3032 // prepare CSRK lookup (does not involve setup) 3033 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3034 3035 // just connected -> everything else happens in sm_run() 3036 if (IS_RESPONDER(sm_conn->sm_role)){ 3037 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3038 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3039 if (sm_slave_request_security) { 3040 // request security if requested by app 3041 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3042 } else { 3043 // otherwise, wait for pairing request 3044 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3045 } 3046 } 3047 break; 3048 } else { 3049 // master 3050 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3051 } 3052 break; 3053 3054 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3055 con_handle = little_endian_read_16(packet, 3); 3056 sm_conn = sm_get_connection_for_handle(con_handle); 3057 if (!sm_conn) break; 3058 3059 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3060 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3061 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3062 break; 3063 } 3064 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3065 // PH2 SEND LTK as we need to exchange keys in PH3 3066 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3067 break; 3068 } 3069 3070 // store rand and ediv 3071 reverse_64(&packet[5], sm_conn->sm_local_rand); 3072 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3073 3074 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3075 // potentially stored LTK is from the master 3076 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3077 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3078 break; 3079 } 3080 3081 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3082 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3083 #else 3084 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3085 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3086 #endif 3087 break; 3088 3089 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3090 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3091 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3092 log_error("Read Local P256 Public Key failed"); 3093 break; 3094 } 3095 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3096 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3097 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3098 sm_log_ec_keypair(); 3099 break; 3100 #endif 3101 default: 3102 break; 3103 } 3104 break; 3105 3106 case HCI_EVENT_ENCRYPTION_CHANGE: 3107 con_handle = little_endian_read_16(packet, 3); 3108 sm_conn = sm_get_connection_for_handle(con_handle); 3109 if (!sm_conn) break; 3110 3111 sm_conn->sm_connection_encrypted = packet[5]; 3112 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3113 sm_conn->sm_actual_encryption_key_size); 3114 log_info("event handler, state %u", sm_conn->sm_engine_state); 3115 if (!sm_conn->sm_connection_encrypted) break; 3116 // continue if part of initial pairing 3117 switch (sm_conn->sm_engine_state){ 3118 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3119 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3120 sm_done_for_handle(sm_conn->sm_handle); 3121 break; 3122 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3123 if (IS_RESPONDER(sm_conn->sm_role)){ 3124 // slave 3125 if (setup->sm_use_secure_connections){ 3126 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3127 } else { 3128 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3129 } 3130 } else { 3131 // master 3132 if (sm_key_distribution_all_received(sm_conn)){ 3133 // skip receiving keys as there are none 3134 sm_key_distribution_handle_all_received(sm_conn); 3135 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3136 } else { 3137 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3138 } 3139 } 3140 break; 3141 default: 3142 break; 3143 } 3144 break; 3145 3146 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3147 con_handle = little_endian_read_16(packet, 3); 3148 sm_conn = sm_get_connection_for_handle(con_handle); 3149 if (!sm_conn) break; 3150 3151 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3152 log_info("event handler, state %u", sm_conn->sm_engine_state); 3153 // continue if part of initial pairing 3154 switch (sm_conn->sm_engine_state){ 3155 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3156 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3157 sm_done_for_handle(sm_conn->sm_handle); 3158 break; 3159 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3160 if (IS_RESPONDER(sm_conn->sm_role)){ 3161 // slave 3162 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3163 } else { 3164 // master 3165 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3166 } 3167 break; 3168 default: 3169 break; 3170 } 3171 break; 3172 3173 3174 case HCI_EVENT_DISCONNECTION_COMPLETE: 3175 con_handle = little_endian_read_16(packet, 3); 3176 sm_done_for_handle(con_handle); 3177 sm_conn = sm_get_connection_for_handle(con_handle); 3178 if (!sm_conn) break; 3179 3180 // delete stored bonding on disconnect with authentication failure in ph0 3181 if (sm_conn->sm_role == 0 3182 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3183 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3184 le_device_db_remove(sm_conn->sm_le_db_index); 3185 } 3186 3187 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3188 sm_conn->sm_handle = 0; 3189 break; 3190 3191 case HCI_EVENT_COMMAND_COMPLETE: 3192 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3193 sm_handle_encryption_result(&packet[6]); 3194 break; 3195 } 3196 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3197 sm_handle_random_result(&packet[6]); 3198 break; 3199 } 3200 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3201 // Hack for Nordic nRF5 series that doesn't have public address: 3202 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3203 // - we use this as default for advertisements/connections 3204 if (hci_get_manufacturer() == BLUETOOTH_COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3205 log_info("nRF5: using (fake) public address as random static address"); 3206 bd_addr_t addr; 3207 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3208 gap_random_address_set(addr); 3209 } 3210 } 3211 break; 3212 default: 3213 break; 3214 } 3215 break; 3216 default: 3217 break; 3218 } 3219 3220 sm_run(); 3221 } 3222 3223 static inline int sm_calc_actual_encryption_key_size(int other){ 3224 if (other < sm_min_encryption_key_size) return 0; 3225 if (other < sm_max_encryption_key_size) return other; 3226 return sm_max_encryption_key_size; 3227 } 3228 3229 3230 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3231 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3232 switch (method){ 3233 case JUST_WORKS: 3234 case NK_BOTH_INPUT: 3235 return 1; 3236 default: 3237 return 0; 3238 } 3239 } 3240 // responder 3241 3242 static int sm_passkey_used(stk_generation_method_t method){ 3243 switch (method){ 3244 case PK_RESP_INPUT: 3245 return 1; 3246 default: 3247 return 0; 3248 } 3249 } 3250 #endif 3251 3252 /** 3253 * @return ok 3254 */ 3255 static int sm_validate_stk_generation_method(void){ 3256 // check if STK generation method is acceptable by client 3257 switch (setup->sm_stk_generation_method){ 3258 case JUST_WORKS: 3259 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3260 case PK_RESP_INPUT: 3261 case PK_INIT_INPUT: 3262 case OK_BOTH_INPUT: 3263 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3264 case OOB: 3265 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3266 case NK_BOTH_INPUT: 3267 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3268 return 1; 3269 default: 3270 return 0; 3271 } 3272 } 3273 3274 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3275 3276 UNUSED(size); 3277 3278 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3279 sm_run(); 3280 } 3281 3282 if (packet_type != SM_DATA_PACKET) return; 3283 3284 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3285 if (!sm_conn) return; 3286 3287 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3288 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3289 return; 3290 } 3291 3292 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3293 3294 int err; 3295 UNUSED(err); 3296 3297 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3298 uint8_t buffer[5]; 3299 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3300 buffer[1] = 3; 3301 little_endian_store_16(buffer, 2, con_handle); 3302 buffer[4] = packet[1]; 3303 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3304 return; 3305 } 3306 3307 switch (sm_conn->sm_engine_state){ 3308 3309 // a sm timeout requries a new physical connection 3310 case SM_GENERAL_TIMEOUT: 3311 return; 3312 3313 #ifdef ENABLE_LE_CENTRAL 3314 3315 // Initiator 3316 case SM_INITIATOR_CONNECTED: 3317 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3318 sm_pdu_received_in_wrong_state(sm_conn); 3319 break; 3320 } 3321 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3322 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3323 break; 3324 } 3325 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3326 sm_key_t ltk; 3327 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3328 if (!sm_is_null_key(ltk)){ 3329 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3330 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3331 } else { 3332 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3333 } 3334 break; 3335 } 3336 // otherwise, store security request 3337 sm_conn->sm_security_request_received = 1; 3338 break; 3339 3340 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3341 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3342 sm_pdu_received_in_wrong_state(sm_conn); 3343 break; 3344 } 3345 // store pairing request 3346 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3347 err = sm_stk_generation_init(sm_conn); 3348 if (err){ 3349 setup->sm_pairing_failed_reason = err; 3350 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3351 break; 3352 } 3353 3354 // generate random number first, if we need to show passkey 3355 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3356 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3357 break; 3358 } 3359 3360 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3361 if (setup->sm_use_secure_connections){ 3362 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3363 if (setup->sm_stk_generation_method == JUST_WORKS){ 3364 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3365 sm_trigger_user_response(sm_conn); 3366 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3367 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3368 } 3369 } else { 3370 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3371 } 3372 break; 3373 } 3374 #endif 3375 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3376 sm_trigger_user_response(sm_conn); 3377 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3378 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3379 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3380 } 3381 break; 3382 3383 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3384 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3385 sm_pdu_received_in_wrong_state(sm_conn); 3386 break; 3387 } 3388 3389 // store s_confirm 3390 reverse_128(&packet[1], setup->sm_peer_confirm); 3391 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3392 break; 3393 3394 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3395 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3396 sm_pdu_received_in_wrong_state(sm_conn); 3397 break;; 3398 } 3399 3400 // received random value 3401 reverse_128(&packet[1], setup->sm_peer_random); 3402 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3403 break; 3404 #endif 3405 3406 #ifdef ENABLE_LE_PERIPHERAL 3407 // Responder 3408 case SM_RESPONDER_IDLE: 3409 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3410 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3411 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3412 sm_pdu_received_in_wrong_state(sm_conn); 3413 break;; 3414 } 3415 3416 // store pairing request 3417 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3418 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3419 break; 3420 #endif 3421 3422 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3423 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3424 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3425 sm_pdu_received_in_wrong_state(sm_conn); 3426 break; 3427 } 3428 3429 // store public key for DH Key calculation 3430 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3431 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3432 3433 // validate public key 3434 err = 0; 3435 3436 #ifdef USE_MICROECC_FOR_ECDH 3437 #if uECC_SUPPORTS_secp256r1 3438 // standard version 3439 err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0; 3440 #else 3441 // static version 3442 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3443 #endif 3444 #endif 3445 3446 if (err){ 3447 log_error("sm: peer public key invalid %x", err); 3448 // uses "unspecified reason", there is no "public key invalid" error code 3449 sm_pdu_received_in_wrong_state(sm_conn); 3450 break; 3451 } 3452 3453 if (IS_RESPONDER(sm_conn->sm_role)){ 3454 // responder 3455 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3456 } else { 3457 // initiator 3458 // stk generation method 3459 // passkey entry: notify app to show passkey or to request passkey 3460 switch (setup->sm_stk_generation_method){ 3461 case JUST_WORKS: 3462 case NK_BOTH_INPUT: 3463 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3464 break; 3465 case PK_RESP_INPUT: 3466 sm_sc_start_calculating_local_confirm(sm_conn); 3467 break; 3468 case PK_INIT_INPUT: 3469 case OK_BOTH_INPUT: 3470 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3471 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3472 break; 3473 } 3474 sm_sc_start_calculating_local_confirm(sm_conn); 3475 break; 3476 case OOB: 3477 // TODO: implement SC OOB 3478 break; 3479 } 3480 } 3481 break; 3482 3483 case SM_SC_W4_CONFIRMATION: 3484 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3485 sm_pdu_received_in_wrong_state(sm_conn); 3486 break; 3487 } 3488 // received confirm value 3489 reverse_128(&packet[1], setup->sm_peer_confirm); 3490 3491 if (IS_RESPONDER(sm_conn->sm_role)){ 3492 // responder 3493 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3494 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3495 // still waiting for passkey 3496 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3497 break; 3498 } 3499 } 3500 sm_sc_start_calculating_local_confirm(sm_conn); 3501 } else { 3502 // initiator 3503 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3504 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3505 } else { 3506 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3507 } 3508 } 3509 break; 3510 3511 case SM_SC_W4_PAIRING_RANDOM: 3512 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3513 sm_pdu_received_in_wrong_state(sm_conn); 3514 break; 3515 } 3516 3517 // received random value 3518 reverse_128(&packet[1], setup->sm_peer_nonce); 3519 3520 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3521 // only check for JUST WORK/NC in initiator role AND passkey entry 3522 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3523 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3524 } 3525 3526 sm_sc_state_after_receiving_random(sm_conn); 3527 break; 3528 3529 case SM_SC_W2_CALCULATE_G2: 3530 case SM_SC_W4_CALCULATE_G2: 3531 case SM_SC_W2_CALCULATE_F5_SALT: 3532 case SM_SC_W4_CALCULATE_F5_SALT: 3533 case SM_SC_W2_CALCULATE_F5_MACKEY: 3534 case SM_SC_W4_CALCULATE_F5_MACKEY: 3535 case SM_SC_W2_CALCULATE_F5_LTK: 3536 case SM_SC_W4_CALCULATE_F5_LTK: 3537 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3538 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3539 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3540 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3541 sm_pdu_received_in_wrong_state(sm_conn); 3542 break; 3543 } 3544 // store DHKey Check 3545 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3546 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3547 3548 // have we been only waiting for dhkey check command? 3549 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3550 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3551 } 3552 break; 3553 #endif 3554 3555 #ifdef ENABLE_LE_PERIPHERAL 3556 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3557 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3558 sm_pdu_received_in_wrong_state(sm_conn); 3559 break; 3560 } 3561 3562 // received confirm value 3563 reverse_128(&packet[1], setup->sm_peer_confirm); 3564 3565 // notify client to hide shown passkey 3566 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3567 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3568 } 3569 3570 // handle user cancel pairing? 3571 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3572 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3573 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3574 break; 3575 } 3576 3577 // wait for user action? 3578 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3579 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3580 break; 3581 } 3582 3583 // calculate and send local_confirm 3584 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3585 break; 3586 3587 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3588 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3589 sm_pdu_received_in_wrong_state(sm_conn); 3590 break;; 3591 } 3592 3593 // received random value 3594 reverse_128(&packet[1], setup->sm_peer_random); 3595 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3596 break; 3597 #endif 3598 3599 case SM_PH3_RECEIVE_KEYS: 3600 switch(packet[0]){ 3601 case SM_CODE_ENCRYPTION_INFORMATION: 3602 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3603 reverse_128(&packet[1], setup->sm_peer_ltk); 3604 break; 3605 3606 case SM_CODE_MASTER_IDENTIFICATION: 3607 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3608 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3609 reverse_64(&packet[3], setup->sm_peer_rand); 3610 break; 3611 3612 case SM_CODE_IDENTITY_INFORMATION: 3613 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3614 reverse_128(&packet[1], setup->sm_peer_irk); 3615 break; 3616 3617 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3618 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3619 setup->sm_peer_addr_type = packet[1]; 3620 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3621 break; 3622 3623 case SM_CODE_SIGNING_INFORMATION: 3624 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3625 reverse_128(&packet[1], setup->sm_peer_csrk); 3626 break; 3627 default: 3628 // Unexpected PDU 3629 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3630 break; 3631 } 3632 // done with key distribution? 3633 if (sm_key_distribution_all_received(sm_conn)){ 3634 3635 sm_key_distribution_handle_all_received(sm_conn); 3636 3637 if (IS_RESPONDER(sm_conn->sm_role)){ 3638 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3639 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3640 } else { 3641 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3642 sm_done_for_handle(sm_conn->sm_handle); 3643 } 3644 } else { 3645 if (setup->sm_use_secure_connections){ 3646 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3647 } else { 3648 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3649 } 3650 } 3651 } 3652 break; 3653 default: 3654 // Unexpected PDU 3655 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3656 break; 3657 } 3658 3659 // try to send preparared packet 3660 sm_run(); 3661 } 3662 3663 // Security Manager Client API 3664 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3665 sm_get_oob_data = get_oob_data_callback; 3666 } 3667 3668 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3669 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3670 } 3671 3672 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3673 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3674 } 3675 3676 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3677 sm_min_encryption_key_size = min_size; 3678 sm_max_encryption_key_size = max_size; 3679 } 3680 3681 void sm_set_authentication_requirements(uint8_t auth_req){ 3682 sm_auth_req = auth_req; 3683 } 3684 3685 void sm_set_io_capabilities(io_capability_t io_capability){ 3686 sm_io_capabilities = io_capability; 3687 } 3688 3689 #ifdef ENABLE_LE_PERIPHERAL 3690 void sm_set_request_security(int enable){ 3691 sm_slave_request_security = enable; 3692 } 3693 #endif 3694 3695 void sm_set_er(sm_key_t er){ 3696 memcpy(sm_persistent_er, er, 16); 3697 } 3698 3699 void sm_set_ir(sm_key_t ir){ 3700 memcpy(sm_persistent_ir, ir, 16); 3701 } 3702 3703 // Testing support only 3704 void sm_test_set_irk(sm_key_t irk){ 3705 memcpy(sm_persistent_irk, irk, 16); 3706 sm_persistent_irk_ready = 1; 3707 } 3708 3709 void sm_test_use_fixed_local_csrk(void){ 3710 test_use_fixed_local_csrk = 1; 3711 } 3712 3713 void sm_init(void){ 3714 // set some (BTstack default) ER and IR 3715 int i; 3716 sm_key_t er; 3717 sm_key_t ir; 3718 for (i=0;i<16;i++){ 3719 er[i] = 0x30 + i; 3720 ir[i] = 0x90 + i; 3721 } 3722 sm_set_er(er); 3723 sm_set_ir(ir); 3724 // defaults 3725 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3726 | SM_STK_GENERATION_METHOD_OOB 3727 | SM_STK_GENERATION_METHOD_PASSKEY 3728 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3729 3730 sm_max_encryption_key_size = 16; 3731 sm_min_encryption_key_size = 7; 3732 3733 #ifdef ENABLE_CMAC_ENGINE 3734 sm_cmac_state = CMAC_IDLE; 3735 #endif 3736 dkg_state = DKG_W4_WORKING; 3737 rau_state = RAU_W4_WORKING; 3738 sm_aes128_state = SM_AES128_IDLE; 3739 sm_address_resolution_test = -1; // no private address to resolve yet 3740 sm_address_resolution_ah_calculation_active = 0; 3741 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3742 sm_address_resolution_general_queue = NULL; 3743 3744 gap_random_adress_update_period = 15 * 60 * 1000L; 3745 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 3746 3747 test_use_fixed_local_csrk = 0; 3748 3749 // register for HCI Events from HCI 3750 hci_event_callback_registration.callback = &sm_event_packet_handler; 3751 hci_add_event_handler(&hci_event_callback_registration); 3752 3753 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3754 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3755 3756 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3757 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3758 #endif 3759 } 3760 3761 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3762 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3763 memcpy(&ec_q[0], qx, 32); 3764 memcpy(&ec_q[32], qy, 32); 3765 memcpy(ec_d, d, 32); 3766 sm_have_ec_keypair = 1; 3767 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3768 #else 3769 UNUSED(qx); 3770 UNUSED(qy); 3771 UNUSED(d); 3772 #endif 3773 } 3774 3775 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3776 static void parse_hex(uint8_t * buffer, const char * hex_string){ 3777 while (*hex_string){ 3778 int high_nibble = nibble_for_char(*hex_string++); 3779 int low_nibble = nibble_for_char(*hex_string++); 3780 *buffer++ = (high_nibble << 4) | low_nibble; 3781 } 3782 } 3783 #endif 3784 3785 void sm_test_use_fixed_ec_keypair(void){ 3786 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3787 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 3788 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 3789 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 3790 parse_hex(ec_d, ec_d_string); 3791 parse_hex(&ec_q[0], ec_qx_string); 3792 parse_hex(&ec_q[32], ec_qy_string); 3793 sm_have_ec_keypair = 1; 3794 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3795 #endif 3796 } 3797 3798 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3799 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3800 if (!hci_con) return NULL; 3801 return &hci_con->sm_connection; 3802 } 3803 3804 // @returns 0 if not encrypted, 7-16 otherwise 3805 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3806 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3807 if (!sm_conn) return 0; // wrong connection 3808 if (!sm_conn->sm_connection_encrypted) return 0; 3809 return sm_conn->sm_actual_encryption_key_size; 3810 } 3811 3812 int sm_authenticated(hci_con_handle_t con_handle){ 3813 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3814 if (!sm_conn) return 0; // wrong connection 3815 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3816 return sm_conn->sm_connection_authenticated; 3817 } 3818 3819 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3820 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3821 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3822 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3823 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3824 return sm_conn->sm_connection_authorization_state; 3825 } 3826 3827 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3828 switch (sm_conn->sm_engine_state){ 3829 case SM_GENERAL_IDLE: 3830 case SM_RESPONDER_IDLE: 3831 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3832 sm_run(); 3833 break; 3834 default: 3835 break; 3836 } 3837 } 3838 3839 /** 3840 * @brief Trigger Security Request 3841 */ 3842 void sm_send_security_request(hci_con_handle_t con_handle){ 3843 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3844 if (!sm_conn) return; 3845 sm_send_security_request_for_connection(sm_conn); 3846 } 3847 3848 // request pairing 3849 void sm_request_pairing(hci_con_handle_t con_handle){ 3850 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3851 if (!sm_conn) return; // wrong connection 3852 3853 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3854 if (IS_RESPONDER(sm_conn->sm_role)){ 3855 sm_send_security_request_for_connection(sm_conn); 3856 } else { 3857 // used as a trigger to start central/master/initiator security procedures 3858 uint16_t ediv; 3859 sm_key_t ltk; 3860 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3861 switch (sm_conn->sm_irk_lookup_state){ 3862 case IRK_LOOKUP_FAILED: 3863 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3864 break; 3865 case IRK_LOOKUP_SUCCEEDED: 3866 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3867 if (!sm_is_null_key(ltk) || ediv){ 3868 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3869 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3870 } else { 3871 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3872 } 3873 break; 3874 default: 3875 sm_conn->sm_bonding_requested = 1; 3876 break; 3877 } 3878 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3879 sm_conn->sm_bonding_requested = 1; 3880 } 3881 } 3882 sm_run(); 3883 } 3884 3885 // called by client app on authorization request 3886 void sm_authorization_decline(hci_con_handle_t con_handle){ 3887 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3888 if (!sm_conn) return; // wrong connection 3889 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3890 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3891 } 3892 3893 void sm_authorization_grant(hci_con_handle_t con_handle){ 3894 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3895 if (!sm_conn) return; // wrong connection 3896 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3897 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3898 } 3899 3900 // GAP Bonding API 3901 3902 void sm_bonding_decline(hci_con_handle_t con_handle){ 3903 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3904 if (!sm_conn) return; // wrong connection 3905 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3906 3907 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3908 switch (setup->sm_stk_generation_method){ 3909 case PK_RESP_INPUT: 3910 case PK_INIT_INPUT: 3911 case OK_BOTH_INPUT: 3912 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3913 break; 3914 case NK_BOTH_INPUT: 3915 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3916 break; 3917 case JUST_WORKS: 3918 case OOB: 3919 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3920 break; 3921 } 3922 } 3923 sm_run(); 3924 } 3925 3926 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3927 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3928 if (!sm_conn) return; // wrong connection 3929 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3930 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3931 if (setup->sm_use_secure_connections){ 3932 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3933 } else { 3934 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3935 } 3936 } 3937 3938 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3939 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3940 sm_sc_prepare_dhkey_check(sm_conn); 3941 } 3942 #endif 3943 3944 sm_run(); 3945 } 3946 3947 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3948 // for now, it's the same 3949 sm_just_works_confirm(con_handle); 3950 } 3951 3952 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3953 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3954 if (!sm_conn) return; // wrong connection 3955 sm_reset_tk(); 3956 big_endian_store_32(setup->sm_tk, 12, passkey); 3957 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3958 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3959 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3960 } 3961 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3962 memcpy(setup->sm_ra, setup->sm_tk, 16); 3963 memcpy(setup->sm_rb, setup->sm_tk, 16); 3964 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3965 sm_sc_start_calculating_local_confirm(sm_conn); 3966 } 3967 #endif 3968 sm_run(); 3969 } 3970 3971 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3972 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3973 if (!sm_conn) return; // wrong connection 3974 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3975 setup->sm_keypress_notification = action; 3976 sm_run(); 3977 } 3978 3979 /** 3980 * @brief Identify device in LE Device DB 3981 * @param handle 3982 * @returns index from le_device_db or -1 if not found/identified 3983 */ 3984 int sm_le_device_index(hci_con_handle_t con_handle ){ 3985 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3986 if (!sm_conn) return -1; 3987 return sm_conn->sm_le_db_index; 3988 } 3989 3990 static int gap_random_address_type_requires_updates(void){ 3991 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3992 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3993 return 1; 3994 } 3995 3996 static uint8_t own_address_type(void){ 3997 switch (gap_random_adress_type){ 3998 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3999 return BD_ADDR_TYPE_LE_PUBLIC; 4000 default: 4001 return BD_ADDR_TYPE_LE_RANDOM; 4002 } 4003 } 4004 4005 // GAP LE API 4006 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4007 gap_random_address_update_stop(); 4008 gap_random_adress_type = random_address_type; 4009 hci_le_set_own_address_type(own_address_type()); 4010 if (!gap_random_address_type_requires_updates()) return; 4011 gap_random_address_update_start(); 4012 gap_random_address_trigger(); 4013 } 4014 4015 gap_random_address_type_t gap_random_address_get_mode(void){ 4016 return gap_random_adress_type; 4017 } 4018 4019 void gap_random_address_set_update_period(int period_ms){ 4020 gap_random_adress_update_period = period_ms; 4021 if (!gap_random_address_type_requires_updates()) return; 4022 gap_random_address_update_stop(); 4023 gap_random_address_update_start(); 4024 } 4025 4026 void gap_random_address_set(bd_addr_t addr){ 4027 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4028 memcpy(sm_random_address, addr, 6); 4029 if (rau_state == RAU_W4_WORKING) return; 4030 rau_state = RAU_SET_ADDRESS; 4031 sm_run(); 4032 } 4033 4034 #ifdef ENABLE_LE_PERIPHERAL 4035 /* 4036 * @brief Set Advertisement Paramters 4037 * @param adv_int_min 4038 * @param adv_int_max 4039 * @param adv_type 4040 * @param direct_address_type 4041 * @param direct_address 4042 * @param channel_map 4043 * @param filter_policy 4044 * 4045 * @note own_address_type is used from gap_random_address_set_mode 4046 */ 4047 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4048 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4049 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4050 direct_address_typ, direct_address, channel_map, filter_policy); 4051 } 4052 #endif 4053 4054