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_MBEDTLS_FOR_ECDH 83 #define USE_MICROECC_FOR_ECDH 84 #endif 85 #endif 86 87 // Software ECDH implementation provided by mbedtls 88 #ifdef USE_MBEDTLS_FOR_ECDH 89 #include "mbedtls/config.h" 90 #include "mbedtls/platform.h" 91 #include "mbedtls/ecp.h" 92 #include "sm_mbedtls_allocator.h" 93 #endif 94 95 // Software ECDH implementation provided by micro-ecc 96 #ifdef USE_MICROECC_FOR_ECDH 97 #include "uECC.h" 98 #endif 99 100 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 101 #define ENABLE_CMAC_ENGINE 102 #endif 103 104 // 105 // SM internal types and globals 106 // 107 108 typedef enum { 109 DKG_W4_WORKING, 110 DKG_CALC_IRK, 111 DKG_W4_IRK, 112 DKG_CALC_DHK, 113 DKG_W4_DHK, 114 DKG_READY 115 } derived_key_generation_t; 116 117 typedef enum { 118 RAU_W4_WORKING, 119 RAU_IDLE, 120 RAU_GET_RANDOM, 121 RAU_W4_RANDOM, 122 RAU_GET_ENC, 123 RAU_W4_ENC, 124 RAU_SET_ADDRESS, 125 } random_address_update_t; 126 127 typedef enum { 128 CMAC_IDLE, 129 CMAC_CALC_SUBKEYS, 130 CMAC_W4_SUBKEYS, 131 CMAC_CALC_MI, 132 CMAC_W4_MI, 133 CMAC_CALC_MLAST, 134 CMAC_W4_MLAST 135 } cmac_state_t; 136 137 typedef enum { 138 JUST_WORKS, 139 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 140 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 141 OK_BOTH_INPUT, // Only input on both, both input PK 142 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 143 OOB // OOB available on both sides 144 } stk_generation_method_t; 145 146 typedef enum { 147 SM_USER_RESPONSE_IDLE, 148 SM_USER_RESPONSE_PENDING, 149 SM_USER_RESPONSE_CONFIRM, 150 SM_USER_RESPONSE_PASSKEY, 151 SM_USER_RESPONSE_DECLINE 152 } sm_user_response_t; 153 154 typedef enum { 155 SM_AES128_IDLE, 156 SM_AES128_ACTIVE 157 } sm_aes128_state_t; 158 159 typedef enum { 160 ADDRESS_RESOLUTION_IDLE, 161 ADDRESS_RESOLUTION_GENERAL, 162 ADDRESS_RESOLUTION_FOR_CONNECTION, 163 } address_resolution_mode_t; 164 165 typedef enum { 166 ADDRESS_RESOLUTION_SUCEEDED, 167 ADDRESS_RESOLUTION_FAILED, 168 } address_resolution_event_t; 169 170 typedef enum { 171 EC_KEY_GENERATION_IDLE, 172 EC_KEY_GENERATION_ACTIVE, 173 EC_KEY_GENERATION_W4_KEY, 174 EC_KEY_GENERATION_DONE, 175 } ec_key_generation_state_t; 176 177 typedef enum { 178 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 179 } sm_state_var_t; 180 181 // 182 // GLOBAL DATA 183 // 184 185 static uint8_t test_use_fixed_local_csrk; 186 187 // configuration 188 static uint8_t sm_accepted_stk_generation_methods; 189 static uint8_t sm_max_encryption_key_size; 190 static uint8_t sm_min_encryption_key_size; 191 static uint8_t sm_auth_req = 0; 192 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 193 static uint8_t sm_slave_request_security; 194 #ifdef ENABLE_LE_SECURE_CONNECTIONS 195 static uint8_t sm_have_ec_keypair; 196 #endif 197 198 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 199 static sm_key_t sm_persistent_er; 200 static sm_key_t sm_persistent_ir; 201 202 // derived from sm_persistent_ir 203 static sm_key_t sm_persistent_dhk; 204 static sm_key_t sm_persistent_irk; 205 static uint8_t sm_persistent_irk_ready = 0; // used for testing 206 static derived_key_generation_t dkg_state; 207 208 // derived from sm_persistent_er 209 // .. 210 211 // random address update 212 static random_address_update_t rau_state; 213 static bd_addr_t sm_random_address; 214 215 // CMAC Calculation: General 216 #ifdef ENABLE_CMAC_ENGINE 217 static cmac_state_t sm_cmac_state; 218 static uint16_t sm_cmac_message_len; 219 static sm_key_t sm_cmac_k; 220 static sm_key_t sm_cmac_x; 221 static sm_key_t sm_cmac_m_last; 222 static uint8_t sm_cmac_block_current; 223 static uint8_t sm_cmac_block_count; 224 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 225 static void (*sm_cmac_done_handler)(uint8_t * hash); 226 #endif 227 228 // CMAC for ATT Signed Writes 229 #ifdef ENABLE_LE_SIGNED_WRITE 230 static uint8_t sm_cmac_header[3]; 231 static const uint8_t * sm_cmac_message; 232 static uint8_t sm_cmac_sign_counter[4]; 233 #endif 234 235 // CMAC for Secure Connection functions 236 #ifdef ENABLE_LE_SECURE_CONNECTIONS 237 static sm_connection_t * sm_cmac_connection; 238 static uint8_t sm_cmac_sc_buffer[80]; 239 #endif 240 241 // resolvable private address lookup / CSRK calculation 242 static int sm_address_resolution_test; 243 static int sm_address_resolution_ah_calculation_active; 244 static uint8_t sm_address_resolution_addr_type; 245 static bd_addr_t sm_address_resolution_address; 246 static void * sm_address_resolution_context; 247 static address_resolution_mode_t sm_address_resolution_mode; 248 static btstack_linked_list_t sm_address_resolution_general_queue; 249 250 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 251 static sm_aes128_state_t sm_aes128_state; 252 static void * sm_aes128_context; 253 254 // random engine. store context (ususally sm_connection_t) 255 static void * sm_random_context; 256 257 // to receive hci events 258 static btstack_packet_callback_registration_t hci_event_callback_registration; 259 260 /* to dispatch sm event */ 261 static btstack_linked_list_t sm_event_handlers; 262 263 // LE Secure Connections 264 #ifdef ENABLE_LE_SECURE_CONNECTIONS 265 static ec_key_generation_state_t ec_key_generation_state; 266 static uint8_t ec_d[32]; 267 static uint8_t ec_q[64]; 268 #endif 269 270 // Software ECDH implementation provided by mbedtls 271 #ifdef USE_MBEDTLS_FOR_ECDH 272 // group is always valid 273 static mbedtls_ecp_group mbedtls_ec_group; 274 #ifndef HAVE_MALLOC 275 // COMP Method with Window 2 276 // 1300 bytes with 23 allocations 277 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 278 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 279 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 280 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 281 #endif 282 #endif 283 284 // 285 // Volume 3, Part H, Chapter 24 286 // "Security shall be initiated by the Security Manager in the device in the master role. 287 // The device in the slave role shall be the responding device." 288 // -> master := initiator, slave := responder 289 // 290 291 // data needed for security setup 292 typedef struct sm_setup_context { 293 294 btstack_timer_source_t sm_timeout; 295 296 // used in all phases 297 uint8_t sm_pairing_failed_reason; 298 299 // user response, (Phase 1 and/or 2) 300 uint8_t sm_user_response; 301 uint8_t sm_keypress_notification; 302 303 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 304 int sm_key_distribution_send_set; 305 int sm_key_distribution_received_set; 306 307 // Phase 2 (Pairing over SMP) 308 stk_generation_method_t sm_stk_generation_method; 309 sm_key_t sm_tk; 310 uint8_t sm_use_secure_connections; 311 312 sm_key_t sm_c1_t3_value; // c1 calculation 313 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 314 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 315 sm_key_t sm_local_random; 316 sm_key_t sm_local_confirm; 317 sm_key_t sm_peer_random; 318 sm_key_t sm_peer_confirm; 319 uint8_t sm_m_addr_type; // address and type can be removed 320 uint8_t sm_s_addr_type; // '' 321 bd_addr_t sm_m_address; // '' 322 bd_addr_t sm_s_address; // '' 323 sm_key_t sm_ltk; 324 325 uint8_t sm_state_vars; 326 #ifdef ENABLE_LE_SECURE_CONNECTIONS 327 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 328 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 329 sm_key_t sm_local_nonce; // might be combined with sm_local_random 330 sm_key_t sm_peer_dhkey_check; 331 sm_key_t sm_local_dhkey_check; 332 sm_key_t sm_ra; 333 sm_key_t sm_rb; 334 sm_key_t sm_t; // used for f5 and h6 335 sm_key_t sm_mackey; 336 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 337 #endif 338 339 // Phase 3 340 341 // key distribution, we generate 342 uint16_t sm_local_y; 343 uint16_t sm_local_div; 344 uint16_t sm_local_ediv; 345 uint8_t sm_local_rand[8]; 346 sm_key_t sm_local_ltk; 347 sm_key_t sm_local_csrk; 348 sm_key_t sm_local_irk; 349 // sm_local_address/addr_type not needed 350 351 // key distribution, received from peer 352 uint16_t sm_peer_y; 353 uint16_t sm_peer_div; 354 uint16_t sm_peer_ediv; 355 uint8_t sm_peer_rand[8]; 356 sm_key_t sm_peer_ltk; 357 sm_key_t sm_peer_irk; 358 sm_key_t sm_peer_csrk; 359 uint8_t sm_peer_addr_type; 360 bd_addr_t sm_peer_address; 361 362 } sm_setup_context_t; 363 364 // 365 static sm_setup_context_t the_setup; 366 static sm_setup_context_t * setup = &the_setup; 367 368 // active connection - the one for which the_setup is used for 369 static uint16_t sm_active_connection = 0; 370 371 // @returns 1 if oob data is available 372 // stores oob data in provided 16 byte buffer if not null 373 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 374 375 // horizontal: initiator capabilities 376 // vertial: responder capabilities 377 static const stk_generation_method_t stk_generation_method [5] [5] = { 378 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 379 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 380 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 381 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 382 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 383 }; 384 385 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 386 #ifdef ENABLE_LE_SECURE_CONNECTIONS 387 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 388 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 389 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 390 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 391 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 392 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 393 }; 394 #endif 395 396 static void sm_run(void); 397 static void sm_done_for_handle(hci_con_handle_t con_handle); 398 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 399 static inline int sm_calc_actual_encryption_key_size(int other); 400 static int sm_validate_stk_generation_method(void); 401 402 static void log_info_hex16(const char * name, uint16_t value){ 403 log_info("%-6s 0x%04x", name, value); 404 } 405 406 // @returns 1 if all bytes are 0 407 static int sm_is_null(uint8_t * data, int size){ 408 int i; 409 for (i=0; i < size ; i++){ 410 if (data[i]) return 0; 411 } 412 return 1; 413 } 414 415 static int sm_is_null_random(uint8_t random[8]){ 416 return sm_is_null(random, 8); 417 } 418 419 static int sm_is_null_key(uint8_t * key){ 420 return sm_is_null(key, 16); 421 } 422 423 // Key utils 424 static void sm_reset_tk(void){ 425 int i; 426 for (i=0;i<16;i++){ 427 setup->sm_tk[i] = 0; 428 } 429 } 430 431 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 432 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 433 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 434 int i; 435 for (i = max_encryption_size ; i < 16 ; i++){ 436 key[15-i] = 0; 437 } 438 } 439 440 // SMP Timeout implementation 441 442 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 443 // the Security Manager Timer shall be reset and started. 444 // 445 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 446 // 447 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 448 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 449 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 450 // established. 451 452 static void sm_timeout_handler(btstack_timer_source_t * timer){ 453 log_info("SM timeout"); 454 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 455 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 456 sm_done_for_handle(sm_conn->sm_handle); 457 458 // trigger handling of next ready connection 459 sm_run(); 460 } 461 static void sm_timeout_start(sm_connection_t * sm_conn){ 462 btstack_run_loop_remove_timer(&setup->sm_timeout); 463 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 464 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 465 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 466 btstack_run_loop_add_timer(&setup->sm_timeout); 467 } 468 static void sm_timeout_stop(void){ 469 btstack_run_loop_remove_timer(&setup->sm_timeout); 470 } 471 static void sm_timeout_reset(sm_connection_t * sm_conn){ 472 sm_timeout_stop(); 473 sm_timeout_start(sm_conn); 474 } 475 476 // end of sm timeout 477 478 // GAP Random Address updates 479 static gap_random_address_type_t gap_random_adress_type; 480 static btstack_timer_source_t gap_random_address_update_timer; 481 static uint32_t gap_random_adress_update_period; 482 483 static void gap_random_address_trigger(void){ 484 if (rau_state != RAU_IDLE) return; 485 log_info("gap_random_address_trigger"); 486 rau_state = RAU_GET_RANDOM; 487 sm_run(); 488 } 489 490 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 491 UNUSED(timer); 492 493 log_info("GAP Random Address Update due"); 494 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 495 btstack_run_loop_add_timer(&gap_random_address_update_timer); 496 gap_random_address_trigger(); 497 } 498 499 static void gap_random_address_update_start(void){ 500 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 501 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 502 btstack_run_loop_add_timer(&gap_random_address_update_timer); 503 } 504 505 static void gap_random_address_update_stop(void){ 506 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 507 } 508 509 510 static void sm_random_start(void * context){ 511 sm_random_context = context; 512 hci_send_cmd(&hci_le_rand); 513 } 514 515 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 516 // context is made availabe to aes128 result handler by this 517 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 518 sm_aes128_state = SM_AES128_ACTIVE; 519 sm_key_t key_flipped, plaintext_flipped; 520 reverse_128(key, key_flipped); 521 reverse_128(plaintext, plaintext_flipped); 522 sm_aes128_context = context; 523 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 524 } 525 526 // ah(k,r) helper 527 // r = padding || r 528 // r - 24 bit value 529 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 530 // r'= padding || r 531 memset(r_prime, 0, 16); 532 memcpy(&r_prime[13], r, 3); 533 } 534 535 // d1 helper 536 // d' = padding || r || d 537 // d,r - 16 bit values 538 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 539 // d'= padding || r || d 540 memset(d1_prime, 0, 16); 541 big_endian_store_16(d1_prime, 12, r); 542 big_endian_store_16(d1_prime, 14, d); 543 } 544 545 // dm helper 546 // r’ = padding || r 547 // r - 64 bit value 548 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 549 memset(r_prime, 0, 16); 550 memcpy(&r_prime[8], r, 8); 551 } 552 553 // calculate arguments for first AES128 operation in C1 function 554 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){ 555 556 // p1 = pres || preq || rat’ || iat’ 557 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 558 // cant octet of pres becomes the most significant octet of p1. 559 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 560 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 561 // p1 is 0x05000800000302070710000001010001." 562 563 sm_key_t p1; 564 reverse_56(pres, &p1[0]); 565 reverse_56(preq, &p1[7]); 566 p1[14] = rat; 567 p1[15] = iat; 568 log_info_key("p1", p1); 569 log_info_key("r", r); 570 571 // t1 = r xor p1 572 int i; 573 for (i=0;i<16;i++){ 574 t1[i] = r[i] ^ p1[i]; 575 } 576 log_info_key("t1", t1); 577 } 578 579 // calculate arguments for second AES128 operation in C1 function 580 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 581 // p2 = padding || ia || ra 582 // "The least significant octet of ra becomes the least significant octet of p2 and 583 // the most significant octet of padding becomes the most significant octet of p2. 584 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 585 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 586 587 sm_key_t p2; 588 memset(p2, 0, 16); 589 memcpy(&p2[4], ia, 6); 590 memcpy(&p2[10], ra, 6); 591 log_info_key("p2", p2); 592 593 // c1 = e(k, t2_xor_p2) 594 int i; 595 for (i=0;i<16;i++){ 596 t3[i] = t2[i] ^ p2[i]; 597 } 598 log_info_key("t3", t3); 599 } 600 601 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 602 log_info_key("r1", r1); 603 log_info_key("r2", r2); 604 memcpy(&r_prime[8], &r2[8], 8); 605 memcpy(&r_prime[0], &r1[8], 8); 606 } 607 608 #ifdef ENABLE_LE_SECURE_CONNECTIONS 609 // Software implementations of crypto toolbox for LE Secure Connection 610 // TODO: replace with code to use AES Engine of HCI Controller 611 typedef uint8_t sm_key24_t[3]; 612 typedef uint8_t sm_key56_t[7]; 613 typedef uint8_t sm_key256_t[32]; 614 615 #if 0 616 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 617 uint32_t rk[RKLENGTH(KEYBITS)]; 618 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 619 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 620 } 621 622 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 623 memcpy(k1, k0, 16); 624 sm_shift_left_by_one_bit_inplace(16, k1); 625 if (k0[0] & 0x80){ 626 k1[15] ^= 0x87; 627 } 628 memcpy(k2, k1, 16); 629 sm_shift_left_by_one_bit_inplace(16, k2); 630 if (k1[0] & 0x80){ 631 k2[15] ^= 0x87; 632 } 633 } 634 635 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 636 sm_key_t k0, k1, k2, zero; 637 memset(zero, 0, 16); 638 639 aes128_calc_cyphertext(key, zero, k0); 640 calc_subkeys(k0, k1, k2); 641 642 int cmac_block_count = (cmac_message_len + 15) / 16; 643 644 // step 3: .. 645 if (cmac_block_count==0){ 646 cmac_block_count = 1; 647 } 648 649 // step 4: set m_last 650 sm_key_t cmac_m_last; 651 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 652 int i; 653 if (sm_cmac_last_block_complete){ 654 for (i=0;i<16;i++){ 655 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 656 } 657 } else { 658 int valid_octets_in_last_block = cmac_message_len & 0x0f; 659 for (i=0;i<16;i++){ 660 if (i < valid_octets_in_last_block){ 661 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 662 continue; 663 } 664 if (i == valid_octets_in_last_block){ 665 cmac_m_last[i] = 0x80 ^ k2[i]; 666 continue; 667 } 668 cmac_m_last[i] = k2[i]; 669 } 670 } 671 672 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 673 // LOG_KEY(cmac_m_last); 674 675 // Step 5 676 sm_key_t cmac_x; 677 memset(cmac_x, 0, 16); 678 679 // Step 6 680 sm_key_t sm_cmac_y; 681 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 682 for (i=0;i<16;i++){ 683 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 684 } 685 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 686 } 687 for (i=0;i<16;i++){ 688 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 689 } 690 691 // Step 7 692 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 693 } 694 #endif 695 #endif 696 697 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){ 698 event[0] = type; 699 event[1] = event_size - 2; 700 little_endian_store_16(event, 2, con_handle); 701 event[4] = addr_type; 702 reverse_bd_addr(address, &event[5]); 703 } 704 705 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 706 UNUSED(channel); 707 708 // log event 709 hci_dump_packet(packet_type, 1, packet, size); 710 // dispatch to all event handlers 711 btstack_linked_list_iterator_t it; 712 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 713 while (btstack_linked_list_iterator_has_next(&it)){ 714 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 715 entry->callback(packet_type, 0, packet, size); 716 } 717 } 718 719 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 720 uint8_t event[11]; 721 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 722 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 723 } 724 725 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){ 726 uint8_t event[15]; 727 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 728 little_endian_store_32(event, 11, passkey); 729 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 730 } 731 732 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){ 733 // fetch addr and addr type from db 734 bd_addr_t identity_address; 735 int identity_address_type; 736 le_device_db_info(index, &identity_address_type, identity_address, NULL); 737 738 uint8_t event[19]; 739 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 740 event[11] = identity_address_type; 741 reverse_bd_addr(identity_address, &event[12]); 742 event[18] = index; 743 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 744 } 745 746 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){ 747 748 uint8_t event[18]; 749 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 750 event[11] = result; 751 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 752 } 753 754 // decide on stk generation based on 755 // - pairing request 756 // - io capabilities 757 // - OOB data availability 758 static void sm_setup_tk(void){ 759 760 // default: just works 761 setup->sm_stk_generation_method = JUST_WORKS; 762 763 #ifdef ENABLE_LE_SECURE_CONNECTIONS 764 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 765 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 766 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 767 memset(setup->sm_ra, 0, 16); 768 memset(setup->sm_rb, 0, 16); 769 #else 770 setup->sm_use_secure_connections = 0; 771 #endif 772 773 // If both devices have not set the MITM option in the Authentication Requirements 774 // Flags, then the IO capabilities shall be ignored and the Just Works association 775 // model shall be used. 776 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 777 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 778 log_info("SM: MITM not required by both -> JUST WORKS"); 779 return; 780 } 781 782 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 783 784 // If both devices have out of band authentication data, then the Authentication 785 // Requirements Flags shall be ignored when selecting the pairing method and the 786 // Out of Band pairing method shall be used. 787 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 788 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 789 log_info("SM: have OOB data"); 790 log_info_key("OOB", setup->sm_tk); 791 setup->sm_stk_generation_method = OOB; 792 return; 793 } 794 795 // Reset TK as it has been setup in sm_init_setup 796 sm_reset_tk(); 797 798 // Also use just works if unknown io capabilites 799 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)){ 800 return; 801 } 802 803 // Otherwise the IO capabilities of the devices shall be used to determine the 804 // pairing method as defined in Table 2.4. 805 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 806 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 807 808 #ifdef ENABLE_LE_SECURE_CONNECTIONS 809 // table not define by default 810 if (setup->sm_use_secure_connections){ 811 generation_method = stk_generation_method_with_secure_connection; 812 } 813 #endif 814 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)]; 815 816 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 817 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); 818 } 819 820 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 821 int flags = 0; 822 if (key_set & SM_KEYDIST_ENC_KEY){ 823 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 824 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 825 } 826 if (key_set & SM_KEYDIST_ID_KEY){ 827 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 828 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 829 } 830 if (key_set & SM_KEYDIST_SIGN){ 831 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 832 } 833 return flags; 834 } 835 836 static void sm_setup_key_distribution(uint8_t key_set){ 837 setup->sm_key_distribution_received_set = 0; 838 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 839 } 840 841 // CSRK Key Lookup 842 843 844 static int sm_address_resolution_idle(void){ 845 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 846 } 847 848 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){ 849 memcpy(sm_address_resolution_address, addr, 6); 850 sm_address_resolution_addr_type = addr_type; 851 sm_address_resolution_test = 0; 852 sm_address_resolution_mode = mode; 853 sm_address_resolution_context = context; 854 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 855 } 856 857 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 858 // check if already in list 859 btstack_linked_list_iterator_t it; 860 sm_lookup_entry_t * entry; 861 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 862 while(btstack_linked_list_iterator_has_next(&it)){ 863 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 864 if (entry->address_type != address_type) continue; 865 if (memcmp(entry->address, address, 6)) continue; 866 // already in list 867 return BTSTACK_BUSY; 868 } 869 entry = btstack_memory_sm_lookup_entry_get(); 870 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 871 entry->address_type = (bd_addr_type_t) address_type; 872 memcpy(entry->address, address, 6); 873 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 874 sm_run(); 875 return 0; 876 } 877 878 // 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 879 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 880 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 881 } 882 static inline void dkg_next_state(void){ 883 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 884 } 885 static inline void rau_next_state(void){ 886 rau_state = (random_address_update_t) (((int)rau_state) + 1); 887 } 888 889 // CMAC calculation using AES Engine 890 #ifdef ENABLE_CMAC_ENGINE 891 892 static inline void sm_cmac_next_state(void){ 893 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 894 } 895 896 static int sm_cmac_last_block_complete(void){ 897 if (sm_cmac_message_len == 0) return 0; 898 return (sm_cmac_message_len & 0x0f) == 0; 899 } 900 901 int sm_cmac_ready(void){ 902 return sm_cmac_state == CMAC_IDLE; 903 } 904 905 // generic cmac calculation 906 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])){ 907 // Generalized CMAC 908 memcpy(sm_cmac_k, key, 16); 909 memset(sm_cmac_x, 0, 16); 910 sm_cmac_block_current = 0; 911 sm_cmac_message_len = message_len; 912 sm_cmac_done_handler = done_callback; 913 sm_cmac_get_byte = get_byte_callback; 914 915 // step 2: n := ceil(len/const_Bsize); 916 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 917 918 // step 3: .. 919 if (sm_cmac_block_count==0){ 920 sm_cmac_block_count = 1; 921 } 922 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 923 924 // first, we need to compute l for k1, k2, and m_last 925 sm_cmac_state = CMAC_CALC_SUBKEYS; 926 927 // let's go 928 sm_run(); 929 } 930 #endif 931 932 // cmac for ATT Message signing 933 #ifdef ENABLE_LE_SIGNED_WRITE 934 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 935 if (offset >= sm_cmac_message_len) { 936 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 937 return 0; 938 } 939 940 offset = sm_cmac_message_len - 1 - offset; 941 942 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 943 if (offset < 3){ 944 return sm_cmac_header[offset]; 945 } 946 int actual_message_len_incl_header = sm_cmac_message_len - 4; 947 if (offset < actual_message_len_incl_header){ 948 return sm_cmac_message[offset - 3]; 949 } 950 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 951 } 952 953 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)){ 954 // ATT Message Signing 955 sm_cmac_header[0] = opcode; 956 little_endian_store_16(sm_cmac_header, 1, con_handle); 957 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 958 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 959 sm_cmac_message = message; 960 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 961 } 962 #endif 963 964 #ifdef ENABLE_CMAC_ENGINE 965 static void sm_cmac_handle_aes_engine_ready(void){ 966 switch (sm_cmac_state){ 967 case CMAC_CALC_SUBKEYS: { 968 sm_key_t const_zero; 969 memset(const_zero, 0, 16); 970 sm_cmac_next_state(); 971 sm_aes128_start(sm_cmac_k, const_zero, NULL); 972 break; 973 } 974 case CMAC_CALC_MI: { 975 int j; 976 sm_key_t y; 977 for (j=0;j<16;j++){ 978 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 979 } 980 sm_cmac_block_current++; 981 sm_cmac_next_state(); 982 sm_aes128_start(sm_cmac_k, y, NULL); 983 break; 984 } 985 case CMAC_CALC_MLAST: { 986 int i; 987 sm_key_t y; 988 for (i=0;i<16;i++){ 989 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 990 } 991 log_info_key("Y", y); 992 sm_cmac_block_current++; 993 sm_cmac_next_state(); 994 sm_aes128_start(sm_cmac_k, y, NULL); 995 break; 996 } 997 default: 998 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 999 break; 1000 } 1001 } 1002 1003 // CMAC Implementation using AES128 engine 1004 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1005 int i; 1006 int carry = 0; 1007 for (i=len-1; i >= 0 ; i--){ 1008 int new_carry = data[i] >> 7; 1009 data[i] = data[i] << 1 | carry; 1010 carry = new_carry; 1011 } 1012 } 1013 1014 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1015 switch (sm_cmac_state){ 1016 case CMAC_W4_SUBKEYS: { 1017 sm_key_t k1; 1018 memcpy(k1, data, 16); 1019 sm_shift_left_by_one_bit_inplace(16, k1); 1020 if (data[0] & 0x80){ 1021 k1[15] ^= 0x87; 1022 } 1023 sm_key_t k2; 1024 memcpy(k2, k1, 16); 1025 sm_shift_left_by_one_bit_inplace(16, k2); 1026 if (k1[0] & 0x80){ 1027 k2[15] ^= 0x87; 1028 } 1029 1030 log_info_key("k", sm_cmac_k); 1031 log_info_key("k1", k1); 1032 log_info_key("k2", k2); 1033 1034 // step 4: set m_last 1035 int i; 1036 if (sm_cmac_last_block_complete()){ 1037 for (i=0;i<16;i++){ 1038 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1039 } 1040 } else { 1041 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1042 for (i=0;i<16;i++){ 1043 if (i < valid_octets_in_last_block){ 1044 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1045 continue; 1046 } 1047 if (i == valid_octets_in_last_block){ 1048 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1049 continue; 1050 } 1051 sm_cmac_m_last[i] = k2[i]; 1052 } 1053 } 1054 1055 // next 1056 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1057 break; 1058 } 1059 case CMAC_W4_MI: 1060 memcpy(sm_cmac_x, data, 16); 1061 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1062 break; 1063 case CMAC_W4_MLAST: 1064 // done 1065 log_info("Setting CMAC Engine to IDLE"); 1066 sm_cmac_state = CMAC_IDLE; 1067 log_info_key("CMAC", data); 1068 sm_cmac_done_handler(data); 1069 break; 1070 default: 1071 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1072 break; 1073 } 1074 } 1075 #endif 1076 1077 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1078 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1079 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1080 switch (setup->sm_stk_generation_method){ 1081 case PK_RESP_INPUT: 1082 if (IS_RESPONDER(sm_conn->sm_role)){ 1083 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1084 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1085 } else { 1086 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)); 1087 } 1088 break; 1089 case PK_INIT_INPUT: 1090 if (IS_RESPONDER(sm_conn->sm_role)){ 1091 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)); 1092 } else { 1093 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1094 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1095 } 1096 break; 1097 case OK_BOTH_INPUT: 1098 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1099 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1100 break; 1101 case NK_BOTH_INPUT: 1102 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1103 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)); 1104 break; 1105 case JUST_WORKS: 1106 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1107 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1108 break; 1109 case OOB: 1110 // client already provided OOB data, let's skip notification. 1111 break; 1112 } 1113 } 1114 1115 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1116 int recv_flags; 1117 if (IS_RESPONDER(sm_conn->sm_role)){ 1118 // slave / responder 1119 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1120 } else { 1121 // master / initiator 1122 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1123 } 1124 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1125 return recv_flags == setup->sm_key_distribution_received_set; 1126 } 1127 1128 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1129 if (sm_active_connection == con_handle){ 1130 sm_timeout_stop(); 1131 sm_active_connection = 0; 1132 log_info("sm: connection 0x%x released setup context", con_handle); 1133 } 1134 } 1135 1136 static int sm_key_distribution_flags_for_auth_req(void){ 1137 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1138 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1139 // encryption information only if bonding requested 1140 flags |= SM_KEYDIST_ENC_KEY; 1141 } 1142 return flags; 1143 } 1144 1145 static void sm_reset_setup(void){ 1146 // fill in sm setup 1147 setup->sm_state_vars = 0; 1148 setup->sm_keypress_notification = 0xff; 1149 sm_reset_tk(); 1150 } 1151 1152 static void sm_init_setup(sm_connection_t * sm_conn){ 1153 1154 // fill in sm setup 1155 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1156 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1157 1158 // query client for OOB data 1159 int have_oob_data = 0; 1160 if (sm_get_oob_data) { 1161 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1162 } 1163 1164 sm_pairing_packet_t * local_packet; 1165 if (IS_RESPONDER(sm_conn->sm_role)){ 1166 // slave 1167 local_packet = &setup->sm_s_pres; 1168 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1169 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1170 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1171 } else { 1172 // master 1173 local_packet = &setup->sm_m_preq; 1174 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1175 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1176 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1177 1178 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1179 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1180 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1181 } 1182 1183 uint8_t auth_req = sm_auth_req; 1184 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1185 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1186 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1187 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1188 } 1189 1190 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1191 1192 sm_pairing_packet_t * remote_packet; 1193 int remote_key_request; 1194 if (IS_RESPONDER(sm_conn->sm_role)){ 1195 // slave / responder 1196 remote_packet = &setup->sm_m_preq; 1197 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1198 } else { 1199 // master / initiator 1200 remote_packet = &setup->sm_s_pres; 1201 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1202 } 1203 1204 // check key size 1205 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1206 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1207 1208 // decide on STK generation method 1209 sm_setup_tk(); 1210 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1211 1212 // check if STK generation method is acceptable by client 1213 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1214 1215 // identical to responder 1216 sm_setup_key_distribution(remote_key_request); 1217 1218 // JUST WORKS doens't provide authentication 1219 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1220 1221 return 0; 1222 } 1223 1224 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1225 1226 // cache and reset context 1227 int matched_device_id = sm_address_resolution_test; 1228 address_resolution_mode_t mode = sm_address_resolution_mode; 1229 void * context = sm_address_resolution_context; 1230 1231 // reset context 1232 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1233 sm_address_resolution_context = NULL; 1234 sm_address_resolution_test = -1; 1235 hci_con_handle_t con_handle = 0; 1236 1237 sm_connection_t * sm_connection; 1238 #ifdef ENABLE_LE_CENTRAL 1239 sm_key_t ltk; 1240 #endif 1241 switch (mode){ 1242 case ADDRESS_RESOLUTION_GENERAL: 1243 break; 1244 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1245 sm_connection = (sm_connection_t *) context; 1246 con_handle = sm_connection->sm_handle; 1247 switch (event){ 1248 case ADDRESS_RESOLUTION_SUCEEDED: 1249 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1250 sm_connection->sm_le_db_index = matched_device_id; 1251 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1252 #ifdef ENABLE_LE_CENTRAL 1253 if (sm_connection->sm_role) break; 1254 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1255 sm_connection->sm_security_request_received = 0; 1256 sm_connection->sm_bonding_requested = 0; 1257 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1258 if (!sm_is_null_key(ltk)){ 1259 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1260 } else { 1261 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1262 } 1263 #endif 1264 break; 1265 case ADDRESS_RESOLUTION_FAILED: 1266 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1267 #ifdef ENABLE_LE_CENTRAL 1268 if (sm_connection->sm_role) break; 1269 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1270 sm_connection->sm_security_request_received = 0; 1271 sm_connection->sm_bonding_requested = 0; 1272 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1273 #endif 1274 break; 1275 } 1276 break; 1277 default: 1278 break; 1279 } 1280 1281 switch (event){ 1282 case ADDRESS_RESOLUTION_SUCEEDED: 1283 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1284 break; 1285 case ADDRESS_RESOLUTION_FAILED: 1286 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1287 break; 1288 } 1289 } 1290 1291 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1292 1293 int le_db_index = -1; 1294 1295 // lookup device based on IRK 1296 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1297 int i; 1298 for (i=0; i < le_device_db_count(); i++){ 1299 sm_key_t irk; 1300 bd_addr_t address; 1301 int address_type; 1302 le_device_db_info(i, &address_type, address, irk); 1303 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1304 log_info("sm: device found for IRK, updating"); 1305 le_db_index = i; 1306 break; 1307 } 1308 } 1309 } 1310 1311 // if not found, lookup via public address if possible 1312 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1313 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1314 int i; 1315 for (i=0; i < le_device_db_count(); i++){ 1316 bd_addr_t address; 1317 int address_type; 1318 le_device_db_info(i, &address_type, address, NULL); 1319 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1320 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1321 log_info("sm: device found for public address, updating"); 1322 le_db_index = i; 1323 break; 1324 } 1325 } 1326 } 1327 1328 // if not found, add to db 1329 if (le_db_index < 0) { 1330 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1331 } 1332 1333 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1334 1335 if (le_db_index >= 0){ 1336 1337 #ifdef ENABLE_LE_SIGNED_WRITE 1338 // store local CSRK 1339 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1340 log_info("sm: store local CSRK"); 1341 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1342 le_device_db_local_counter_set(le_db_index, 0); 1343 } 1344 1345 // store remote CSRK 1346 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1347 log_info("sm: store remote CSRK"); 1348 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1349 le_device_db_remote_counter_set(le_db_index, 0); 1350 } 1351 #endif 1352 // store encryption information for secure connections: LTK generated by ECDH 1353 if (setup->sm_use_secure_connections){ 1354 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1355 uint8_t zero_rand[8]; 1356 memset(zero_rand, 0, 8); 1357 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1358 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1359 } 1360 1361 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1362 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1363 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1364 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1365 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1366 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1367 1368 } 1369 } 1370 1371 // keep le_db_index 1372 sm_conn->sm_le_db_index = le_db_index; 1373 } 1374 1375 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1376 setup->sm_pairing_failed_reason = reason; 1377 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1378 } 1379 1380 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1381 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1382 } 1383 1384 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1385 1386 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1387 static int sm_passkey_used(stk_generation_method_t method); 1388 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1389 1390 static void sm_log_ec_keypair(void){ 1391 log_info("Elliptic curve: X"); 1392 log_info_hexdump(&ec_q[0],32); 1393 log_info("Elliptic curve: Y"); 1394 log_info_hexdump(&ec_q[32],32); 1395 } 1396 1397 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1398 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1399 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1400 } else { 1401 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1402 } 1403 } 1404 1405 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1406 if (IS_RESPONDER(sm_conn->sm_role)){ 1407 // Responder 1408 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1409 } else { 1410 // Initiator role 1411 switch (setup->sm_stk_generation_method){ 1412 case JUST_WORKS: 1413 sm_sc_prepare_dhkey_check(sm_conn); 1414 break; 1415 1416 case NK_BOTH_INPUT: 1417 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1418 break; 1419 case PK_INIT_INPUT: 1420 case PK_RESP_INPUT: 1421 case OK_BOTH_INPUT: 1422 if (setup->sm_passkey_bit < 20) { 1423 sm_sc_start_calculating_local_confirm(sm_conn); 1424 } else { 1425 sm_sc_prepare_dhkey_check(sm_conn); 1426 } 1427 break; 1428 case OOB: 1429 // TODO: implement SC OOB 1430 break; 1431 } 1432 } 1433 } 1434 1435 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1436 return sm_cmac_sc_buffer[offset]; 1437 } 1438 1439 static void sm_sc_cmac_done(uint8_t * hash){ 1440 log_info("sm_sc_cmac_done: "); 1441 log_info_hexdump(hash, 16); 1442 1443 sm_connection_t * sm_conn = sm_cmac_connection; 1444 sm_cmac_connection = NULL; 1445 link_key_type_t link_key_type; 1446 1447 switch (sm_conn->sm_engine_state){ 1448 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1449 memcpy(setup->sm_local_confirm, hash, 16); 1450 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1451 break; 1452 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1453 // check 1454 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1455 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1456 break; 1457 } 1458 sm_sc_state_after_receiving_random(sm_conn); 1459 break; 1460 case SM_SC_W4_CALCULATE_G2: { 1461 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1462 big_endian_store_32(setup->sm_tk, 12, vab); 1463 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1464 sm_trigger_user_response(sm_conn); 1465 break; 1466 } 1467 case SM_SC_W4_CALCULATE_F5_SALT: 1468 memcpy(setup->sm_t, hash, 16); 1469 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1470 break; 1471 case SM_SC_W4_CALCULATE_F5_MACKEY: 1472 memcpy(setup->sm_mackey, hash, 16); 1473 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1474 break; 1475 case SM_SC_W4_CALCULATE_F5_LTK: 1476 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1477 // Errata Service Release to the Bluetooth Specification: ESR09 1478 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1479 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1480 memcpy(setup->sm_ltk, hash, 16); 1481 memcpy(setup->sm_local_ltk, hash, 16); 1482 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1483 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1484 break; 1485 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1486 memcpy(setup->sm_local_dhkey_check, hash, 16); 1487 if (IS_RESPONDER(sm_conn->sm_role)){ 1488 // responder 1489 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1490 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1491 } else { 1492 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1493 } 1494 } else { 1495 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1496 } 1497 break; 1498 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1499 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1500 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1501 break; 1502 } 1503 if (IS_RESPONDER(sm_conn->sm_role)){ 1504 // responder 1505 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1506 } else { 1507 // initiator 1508 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1509 } 1510 break; 1511 case SM_SC_W4_CALCULATE_H6_ILK: 1512 memcpy(setup->sm_t, hash, 16); 1513 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1514 break; 1515 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1516 reverse_128(hash, setup->sm_t); 1517 link_key_type = sm_conn->sm_connection_authenticated ? 1518 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1519 if (IS_RESPONDER(sm_conn->sm_role)){ 1520 #ifdef ENABLE_CLASSIC 1521 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1522 #endif 1523 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1524 } else { 1525 #ifdef ENABLE_CLASSIC 1526 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1527 #endif 1528 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1529 } 1530 sm_done_for_handle(sm_conn->sm_handle); 1531 break; 1532 default: 1533 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1534 break; 1535 } 1536 sm_run(); 1537 } 1538 1539 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){ 1540 const uint16_t message_len = 65; 1541 sm_cmac_connection = sm_conn; 1542 memcpy(sm_cmac_sc_buffer, u, 32); 1543 memcpy(sm_cmac_sc_buffer+32, v, 32); 1544 sm_cmac_sc_buffer[64] = z; 1545 log_info("f4 key"); 1546 log_info_hexdump(x, 16); 1547 log_info("f4 message"); 1548 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1549 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1550 } 1551 1552 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1553 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1554 static const uint8_t f5_length[] = { 0x01, 0x00}; 1555 1556 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1557 #ifdef USE_MBEDTLS_FOR_ECDH 1558 // da * Pb 1559 mbedtls_mpi d; 1560 mbedtls_ecp_point Q; 1561 mbedtls_ecp_point DH; 1562 mbedtls_mpi_init(&d); 1563 mbedtls_ecp_point_init(&Q); 1564 mbedtls_ecp_point_init(&DH); 1565 mbedtls_mpi_read_binary(&d, ec_d, 32); 1566 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); 1567 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 1568 mbedtls_mpi_lset(&Q.Z, 1); 1569 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1570 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1571 mbedtls_ecp_point_free(&DH); 1572 mbedtls_mpi_free(&d); 1573 mbedtls_ecp_point_free(&Q); 1574 #endif 1575 #ifdef USE_MICROECC_FOR_ECDH 1576 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1577 #endif 1578 log_info("dhkey"); 1579 log_info_hexdump(dhkey, 32); 1580 } 1581 1582 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1583 // calculate DHKEY 1584 sm_key256_t dhkey; 1585 sm_sc_calculate_dhkey(dhkey); 1586 1587 // calculate salt for f5 1588 const uint16_t message_len = 32; 1589 sm_cmac_connection = sm_conn; 1590 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1591 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1592 } 1593 1594 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){ 1595 const uint16_t message_len = 53; 1596 sm_cmac_connection = sm_conn; 1597 1598 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1599 sm_cmac_sc_buffer[0] = 0; 1600 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1601 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1602 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1603 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1604 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1605 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1606 log_info("f5 key"); 1607 log_info_hexdump(t, 16); 1608 log_info("f5 message for MacKey"); 1609 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1610 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1611 } 1612 1613 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1614 sm_key56_t bd_addr_master, bd_addr_slave; 1615 bd_addr_master[0] = setup->sm_m_addr_type; 1616 bd_addr_slave[0] = setup->sm_s_addr_type; 1617 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1618 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1619 if (IS_RESPONDER(sm_conn->sm_role)){ 1620 // responder 1621 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1622 } else { 1623 // initiator 1624 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1625 } 1626 } 1627 1628 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1629 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1630 const uint16_t message_len = 53; 1631 sm_cmac_connection = sm_conn; 1632 sm_cmac_sc_buffer[0] = 1; 1633 // 1..52 setup before 1634 log_info("f5 key"); 1635 log_info_hexdump(t, 16); 1636 log_info("f5 message for LTK"); 1637 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1638 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1639 } 1640 1641 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1642 f5_ltk(sm_conn, setup->sm_t); 1643 } 1644 1645 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){ 1646 const uint16_t message_len = 65; 1647 sm_cmac_connection = sm_conn; 1648 memcpy(sm_cmac_sc_buffer, n1, 16); 1649 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1650 memcpy(sm_cmac_sc_buffer+32, r, 16); 1651 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1652 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1653 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1654 log_info("f6 key"); 1655 log_info_hexdump(w, 16); 1656 log_info("f6 message"); 1657 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1658 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1659 } 1660 1661 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1662 // - U is 256 bits 1663 // - V is 256 bits 1664 // - X is 128 bits 1665 // - Y is 128 bits 1666 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){ 1667 const uint16_t message_len = 80; 1668 sm_cmac_connection = sm_conn; 1669 memcpy(sm_cmac_sc_buffer, u, 32); 1670 memcpy(sm_cmac_sc_buffer+32, v, 32); 1671 memcpy(sm_cmac_sc_buffer+64, y, 16); 1672 log_info("g2 key"); 1673 log_info_hexdump(x, 16); 1674 log_info("g2 message"); 1675 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1676 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1677 } 1678 1679 static void g2_calculate(sm_connection_t * sm_conn) { 1680 // calc Va if numeric comparison 1681 if (IS_RESPONDER(sm_conn->sm_role)){ 1682 // responder 1683 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1684 } else { 1685 // initiator 1686 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1687 } 1688 } 1689 1690 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1691 uint8_t z = 0; 1692 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1693 // some form of passkey 1694 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1695 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1696 setup->sm_passkey_bit++; 1697 } 1698 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1699 } 1700 1701 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1702 uint8_t z = 0; 1703 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1704 // some form of passkey 1705 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1706 // sm_passkey_bit was increased before sending confirm value 1707 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1708 } 1709 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1710 } 1711 1712 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1713 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1714 } 1715 1716 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1717 // calculate DHKCheck 1718 sm_key56_t bd_addr_master, bd_addr_slave; 1719 bd_addr_master[0] = setup->sm_m_addr_type; 1720 bd_addr_slave[0] = setup->sm_s_addr_type; 1721 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1722 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1723 uint8_t iocap_a[3]; 1724 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1725 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1726 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1727 uint8_t iocap_b[3]; 1728 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1729 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1730 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1731 if (IS_RESPONDER(sm_conn->sm_role)){ 1732 // responder 1733 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); 1734 } else { 1735 // initiator 1736 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); 1737 } 1738 } 1739 1740 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1741 // validate E = f6() 1742 sm_key56_t bd_addr_master, bd_addr_slave; 1743 bd_addr_master[0] = setup->sm_m_addr_type; 1744 bd_addr_slave[0] = setup->sm_s_addr_type; 1745 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1746 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1747 1748 uint8_t iocap_a[3]; 1749 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1750 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1751 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1752 uint8_t iocap_b[3]; 1753 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1754 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1755 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1756 if (IS_RESPONDER(sm_conn->sm_role)){ 1757 // responder 1758 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); 1759 } else { 1760 // initiator 1761 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); 1762 } 1763 } 1764 1765 1766 // 1767 // Link Key Conversion Function h6 1768 // 1769 // h6(W, keyID) = AES-CMACW(keyID) 1770 // - W is 128 bits 1771 // - keyID is 32 bits 1772 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1773 const uint16_t message_len = 4; 1774 sm_cmac_connection = sm_conn; 1775 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1776 log_info("h6 key"); 1777 log_info_hexdump(w, 16); 1778 log_info("h6 message"); 1779 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1780 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1781 } 1782 1783 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1784 // Errata Service Release to the Bluetooth Specification: ESR09 1785 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1786 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1787 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1788 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1789 } 1790 1791 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1792 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1793 } 1794 1795 #endif 1796 1797 // key management legacy connections: 1798 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1799 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1800 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1801 // - responder reconnects: responder uses LTK receveived from master 1802 1803 // key management secure connections: 1804 // - both devices store same LTK from ECDH key exchange. 1805 1806 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1807 static void sm_load_security_info(sm_connection_t * sm_connection){ 1808 int encryption_key_size; 1809 int authenticated; 1810 int authorized; 1811 1812 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1813 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1814 &encryption_key_size, &authenticated, &authorized); 1815 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1816 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1817 sm_connection->sm_connection_authenticated = authenticated; 1818 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1819 } 1820 #endif 1821 1822 #ifdef ENABLE_LE_PERIPHERAL 1823 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1824 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1825 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1826 // re-establish used key encryption size 1827 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1828 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1829 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1830 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1831 log_info("sm: received ltk request with key size %u, authenticated %u", 1832 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1833 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1834 } 1835 #endif 1836 1837 static void sm_run(void){ 1838 1839 btstack_linked_list_iterator_t it; 1840 1841 // assert that we can send at least commands 1842 if (!hci_can_send_command_packet_now()) return; 1843 1844 // 1845 // non-connection related behaviour 1846 // 1847 1848 // distributed key generation 1849 switch (dkg_state){ 1850 case DKG_CALC_IRK: 1851 // already busy? 1852 if (sm_aes128_state == SM_AES128_IDLE) { 1853 // IRK = d1(IR, 1, 0) 1854 sm_key_t d1_prime; 1855 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1856 dkg_next_state(); 1857 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1858 return; 1859 } 1860 break; 1861 case DKG_CALC_DHK: 1862 // already busy? 1863 if (sm_aes128_state == SM_AES128_IDLE) { 1864 // DHK = d1(IR, 3, 0) 1865 sm_key_t d1_prime; 1866 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1867 dkg_next_state(); 1868 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1869 return; 1870 } 1871 break; 1872 default: 1873 break; 1874 } 1875 1876 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1877 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1878 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 1879 sm_random_start(NULL); 1880 #else 1881 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1882 hci_send_cmd(&hci_le_read_local_p256_public_key); 1883 #endif 1884 return; 1885 } 1886 #endif 1887 1888 // random address updates 1889 switch (rau_state){ 1890 case RAU_GET_RANDOM: 1891 rau_next_state(); 1892 sm_random_start(NULL); 1893 return; 1894 case RAU_GET_ENC: 1895 // already busy? 1896 if (sm_aes128_state == SM_AES128_IDLE) { 1897 sm_key_t r_prime; 1898 sm_ah_r_prime(sm_random_address, r_prime); 1899 rau_next_state(); 1900 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1901 return; 1902 } 1903 break; 1904 case RAU_SET_ADDRESS: 1905 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1906 rau_state = RAU_IDLE; 1907 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1908 return; 1909 default: 1910 break; 1911 } 1912 1913 #ifdef ENABLE_CMAC_ENGINE 1914 // CMAC 1915 switch (sm_cmac_state){ 1916 case CMAC_CALC_SUBKEYS: 1917 case CMAC_CALC_MI: 1918 case CMAC_CALC_MLAST: 1919 // already busy? 1920 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1921 sm_cmac_handle_aes_engine_ready(); 1922 return; 1923 default: 1924 break; 1925 } 1926 #endif 1927 1928 // CSRK Lookup 1929 // -- if csrk lookup ready, find connection that require csrk lookup 1930 if (sm_address_resolution_idle()){ 1931 hci_connections_get_iterator(&it); 1932 while(btstack_linked_list_iterator_has_next(&it)){ 1933 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1934 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1935 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1936 // and start lookup 1937 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); 1938 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1939 break; 1940 } 1941 } 1942 } 1943 1944 // -- if csrk lookup ready, resolved addresses for received addresses 1945 if (sm_address_resolution_idle()) { 1946 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1947 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1948 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1949 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1950 btstack_memory_sm_lookup_entry_free(entry); 1951 } 1952 } 1953 1954 // -- Continue with CSRK device lookup by public or resolvable private address 1955 if (!sm_address_resolution_idle()){ 1956 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1957 while (sm_address_resolution_test < le_device_db_count()){ 1958 int addr_type; 1959 bd_addr_t addr; 1960 sm_key_t irk; 1961 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1962 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1963 1964 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1965 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1966 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1967 break; 1968 } 1969 1970 if (sm_address_resolution_addr_type == 0){ 1971 sm_address_resolution_test++; 1972 continue; 1973 } 1974 1975 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1976 1977 log_info("LE Device Lookup: calculate AH"); 1978 log_info_key("IRK", irk); 1979 1980 sm_key_t r_prime; 1981 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1982 sm_address_resolution_ah_calculation_active = 1; 1983 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1984 return; 1985 } 1986 1987 if (sm_address_resolution_test >= le_device_db_count()){ 1988 log_info("LE Device Lookup: not found"); 1989 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1990 } 1991 } 1992 1993 // handle basic actions that don't requires the full context 1994 hci_connections_get_iterator(&it); 1995 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1996 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1997 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1998 switch(sm_connection->sm_engine_state){ 1999 // responder side 2000 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2001 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2002 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2003 return; 2004 2005 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2006 case SM_SC_RECEIVED_LTK_REQUEST: 2007 switch (sm_connection->sm_irk_lookup_state){ 2008 case IRK_LOOKUP_FAILED: 2009 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2010 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2011 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2012 return; 2013 default: 2014 break; 2015 } 2016 break; 2017 #endif 2018 default: 2019 break; 2020 } 2021 } 2022 2023 // 2024 // active connection handling 2025 // -- use loop to handle next connection if lock on setup context is released 2026 2027 while (1) { 2028 2029 // Find connections that requires setup context and make active if no other is locked 2030 hci_connections_get_iterator(&it); 2031 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 2032 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2033 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2034 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2035 int done = 1; 2036 int err; 2037 UNUSED(err); 2038 switch (sm_connection->sm_engine_state) { 2039 #ifdef ENABLE_LE_PERIPHERAL 2040 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2041 // send packet if possible, 2042 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2043 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2044 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2045 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2046 } else { 2047 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2048 } 2049 // don't lock sxetup context yet 2050 done = 0; 2051 break; 2052 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2053 sm_reset_setup(); 2054 sm_init_setup(sm_connection); 2055 // recover pairing request 2056 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2057 err = sm_stk_generation_init(sm_connection); 2058 if (err){ 2059 setup->sm_pairing_failed_reason = err; 2060 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2061 break; 2062 } 2063 sm_timeout_start(sm_connection); 2064 // generate random number first, if we need to show passkey 2065 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2066 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2067 break; 2068 } 2069 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2070 break; 2071 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2072 sm_reset_setup(); 2073 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2074 break; 2075 #endif 2076 #ifdef ENABLE_LE_CENTRAL 2077 case SM_INITIATOR_PH0_HAS_LTK: 2078 sm_reset_setup(); 2079 sm_load_security_info(sm_connection); 2080 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2081 break; 2082 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2083 sm_reset_setup(); 2084 sm_init_setup(sm_connection); 2085 sm_timeout_start(sm_connection); 2086 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2087 break; 2088 #endif 2089 2090 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2091 case SM_SC_RECEIVED_LTK_REQUEST: 2092 switch (sm_connection->sm_irk_lookup_state){ 2093 case IRK_LOOKUP_SUCCEEDED: 2094 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2095 // start using context by loading security info 2096 sm_reset_setup(); 2097 sm_load_security_info(sm_connection); 2098 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2099 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2100 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2101 break; 2102 } 2103 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2104 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2105 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2106 // don't lock setup context yet 2107 return; 2108 default: 2109 // just wait until IRK lookup is completed 2110 // don't lock setup context yet 2111 done = 0; 2112 break; 2113 } 2114 break; 2115 #endif 2116 default: 2117 done = 0; 2118 break; 2119 } 2120 if (done){ 2121 sm_active_connection = sm_connection->sm_handle; 2122 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2123 } 2124 } 2125 2126 // 2127 // active connection handling 2128 // 2129 2130 if (sm_active_connection == 0) return; 2131 2132 // assert that we could send a SM PDU - not needed for all of the following 2133 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2134 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2135 return; 2136 } 2137 2138 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2139 if (!connection) return; 2140 2141 // send keypress notifications 2142 if (setup->sm_keypress_notification != 0xff){ 2143 uint8_t buffer[2]; 2144 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2145 buffer[1] = setup->sm_keypress_notification; 2146 setup->sm_keypress_notification = 0xff; 2147 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2148 return; 2149 } 2150 2151 sm_key_t plaintext; 2152 int key_distribution_flags; 2153 UNUSED(key_distribution_flags); 2154 2155 log_info("sm_run: state %u", connection->sm_engine_state); 2156 2157 switch (connection->sm_engine_state){ 2158 2159 // general 2160 case SM_GENERAL_SEND_PAIRING_FAILED: { 2161 uint8_t buffer[2]; 2162 buffer[0] = SM_CODE_PAIRING_FAILED; 2163 buffer[1] = setup->sm_pairing_failed_reason; 2164 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2165 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2166 sm_done_for_handle(connection->sm_handle); 2167 break; 2168 } 2169 2170 // responding state 2171 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2172 case SM_SC_W2_GET_RANDOM_A: 2173 sm_random_start(connection); 2174 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2175 break; 2176 case SM_SC_W2_GET_RANDOM_B: 2177 sm_random_start(connection); 2178 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2179 break; 2180 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2181 if (!sm_cmac_ready()) break; 2182 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2183 sm_sc_calculate_local_confirm(connection); 2184 break; 2185 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2186 if (!sm_cmac_ready()) break; 2187 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2188 sm_sc_calculate_remote_confirm(connection); 2189 break; 2190 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2191 if (!sm_cmac_ready()) break; 2192 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2193 sm_sc_calculate_f6_for_dhkey_check(connection); 2194 break; 2195 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2196 if (!sm_cmac_ready()) break; 2197 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2198 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2199 break; 2200 case SM_SC_W2_CALCULATE_F5_SALT: 2201 if (!sm_cmac_ready()) break; 2202 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2203 f5_calculate_salt(connection); 2204 break; 2205 case SM_SC_W2_CALCULATE_F5_MACKEY: 2206 if (!sm_cmac_ready()) break; 2207 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2208 f5_calculate_mackey(connection); 2209 break; 2210 case SM_SC_W2_CALCULATE_F5_LTK: 2211 if (!sm_cmac_ready()) break; 2212 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2213 f5_calculate_ltk(connection); 2214 break; 2215 case SM_SC_W2_CALCULATE_G2: 2216 if (!sm_cmac_ready()) break; 2217 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2218 g2_calculate(connection); 2219 break; 2220 case SM_SC_W2_CALCULATE_H6_ILK: 2221 if (!sm_cmac_ready()) break; 2222 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2223 h6_calculate_ilk(connection); 2224 break; 2225 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2226 if (!sm_cmac_ready()) break; 2227 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2228 h6_calculate_br_edr_link_key(connection); 2229 break; 2230 #endif 2231 2232 #ifdef ENABLE_LE_CENTRAL 2233 // initiator side 2234 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2235 sm_key_t peer_ltk_flipped; 2236 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2237 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2238 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2239 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2240 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2241 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2242 return; 2243 } 2244 2245 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2246 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2247 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2248 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2249 sm_timeout_reset(connection); 2250 break; 2251 #endif 2252 2253 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2254 2255 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2256 uint8_t buffer[65]; 2257 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2258 // 2259 reverse_256(&ec_q[0], &buffer[1]); 2260 reverse_256(&ec_q[32], &buffer[33]); 2261 2262 // stk generation method 2263 // passkey entry: notify app to show passkey or to request passkey 2264 switch (setup->sm_stk_generation_method){ 2265 case JUST_WORKS: 2266 case NK_BOTH_INPUT: 2267 if (IS_RESPONDER(connection->sm_role)){ 2268 // responder 2269 sm_sc_start_calculating_local_confirm(connection); 2270 } else { 2271 // initiator 2272 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2273 } 2274 break; 2275 case PK_INIT_INPUT: 2276 case PK_RESP_INPUT: 2277 case OK_BOTH_INPUT: 2278 // use random TK for display 2279 memcpy(setup->sm_ra, setup->sm_tk, 16); 2280 memcpy(setup->sm_rb, setup->sm_tk, 16); 2281 setup->sm_passkey_bit = 0; 2282 2283 if (IS_RESPONDER(connection->sm_role)){ 2284 // responder 2285 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2286 } else { 2287 // initiator 2288 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2289 } 2290 sm_trigger_user_response(connection); 2291 break; 2292 case OOB: 2293 // TODO: implement SC OOB 2294 break; 2295 } 2296 2297 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2298 sm_timeout_reset(connection); 2299 break; 2300 } 2301 case SM_SC_SEND_CONFIRMATION: { 2302 uint8_t buffer[17]; 2303 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2304 reverse_128(setup->sm_local_confirm, &buffer[1]); 2305 if (IS_RESPONDER(connection->sm_role)){ 2306 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2307 } else { 2308 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2309 } 2310 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2311 sm_timeout_reset(connection); 2312 break; 2313 } 2314 case SM_SC_SEND_PAIRING_RANDOM: { 2315 uint8_t buffer[17]; 2316 buffer[0] = SM_CODE_PAIRING_RANDOM; 2317 reverse_128(setup->sm_local_nonce, &buffer[1]); 2318 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2319 if (IS_RESPONDER(connection->sm_role)){ 2320 // responder 2321 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2322 } else { 2323 // initiator 2324 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2325 } 2326 } else { 2327 if (IS_RESPONDER(connection->sm_role)){ 2328 // responder 2329 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2330 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2331 } else { 2332 sm_sc_prepare_dhkey_check(connection); 2333 } 2334 } else { 2335 // initiator 2336 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2337 } 2338 } 2339 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2340 sm_timeout_reset(connection); 2341 break; 2342 } 2343 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2344 uint8_t buffer[17]; 2345 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2346 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2347 2348 if (IS_RESPONDER(connection->sm_role)){ 2349 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2350 } else { 2351 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2352 } 2353 2354 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2355 sm_timeout_reset(connection); 2356 break; 2357 } 2358 2359 #endif 2360 2361 #ifdef ENABLE_LE_PERIPHERAL 2362 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2363 // echo initiator for now 2364 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2365 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2366 2367 if (setup->sm_use_secure_connections){ 2368 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2369 // skip LTK/EDIV for SC 2370 log_info("sm: dropping encryption information flag"); 2371 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2372 } else { 2373 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2374 } 2375 2376 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); 2377 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); 2378 // update key distribution after ENC was dropped 2379 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2380 2381 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2382 sm_timeout_reset(connection); 2383 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2384 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2385 sm_trigger_user_response(connection); 2386 } 2387 return; 2388 #endif 2389 2390 case SM_PH2_SEND_PAIRING_RANDOM: { 2391 uint8_t buffer[17]; 2392 buffer[0] = SM_CODE_PAIRING_RANDOM; 2393 reverse_128(setup->sm_local_random, &buffer[1]); 2394 if (IS_RESPONDER(connection->sm_role)){ 2395 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2396 } else { 2397 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2398 } 2399 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2400 sm_timeout_reset(connection); 2401 break; 2402 } 2403 2404 case SM_PH2_GET_RANDOM_TK: 2405 case SM_PH2_C1_GET_RANDOM_A: 2406 case SM_PH2_C1_GET_RANDOM_B: 2407 case SM_PH3_GET_RANDOM: 2408 case SM_PH3_GET_DIV: 2409 sm_next_responding_state(connection); 2410 sm_random_start(connection); 2411 return; 2412 2413 case SM_PH2_C1_GET_ENC_B: 2414 case SM_PH2_C1_GET_ENC_D: 2415 // already busy? 2416 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2417 sm_next_responding_state(connection); 2418 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2419 return; 2420 2421 case SM_PH3_LTK_GET_ENC: 2422 case SM_RESPONDER_PH4_LTK_GET_ENC: 2423 // already busy? 2424 if (sm_aes128_state == SM_AES128_IDLE) { 2425 sm_key_t d_prime; 2426 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2427 sm_next_responding_state(connection); 2428 sm_aes128_start(sm_persistent_er, d_prime, connection); 2429 return; 2430 } 2431 break; 2432 2433 case SM_PH3_CSRK_GET_ENC: 2434 // already busy? 2435 if (sm_aes128_state == SM_AES128_IDLE) { 2436 sm_key_t d_prime; 2437 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2438 sm_next_responding_state(connection); 2439 sm_aes128_start(sm_persistent_er, d_prime, connection); 2440 return; 2441 } 2442 break; 2443 2444 case SM_PH2_C1_GET_ENC_C: 2445 // already busy? 2446 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2447 // calculate m_confirm using aes128 engine - step 1 2448 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); 2449 sm_next_responding_state(connection); 2450 sm_aes128_start(setup->sm_tk, plaintext, connection); 2451 break; 2452 case SM_PH2_C1_GET_ENC_A: 2453 // already busy? 2454 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2455 // calculate confirm using aes128 engine - step 1 2456 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); 2457 sm_next_responding_state(connection); 2458 sm_aes128_start(setup->sm_tk, plaintext, connection); 2459 break; 2460 case SM_PH2_CALC_STK: 2461 // already busy? 2462 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2463 // calculate STK 2464 if (IS_RESPONDER(connection->sm_role)){ 2465 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2466 } else { 2467 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2468 } 2469 sm_next_responding_state(connection); 2470 sm_aes128_start(setup->sm_tk, plaintext, connection); 2471 break; 2472 case SM_PH3_Y_GET_ENC: 2473 // already busy? 2474 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2475 // PH3B2 - calculate Y from - enc 2476 // Y = dm(DHK, Rand) 2477 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2478 sm_next_responding_state(connection); 2479 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2480 return; 2481 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2482 uint8_t buffer[17]; 2483 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2484 reverse_128(setup->sm_local_confirm, &buffer[1]); 2485 if (IS_RESPONDER(connection->sm_role)){ 2486 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2487 } else { 2488 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2489 } 2490 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2491 sm_timeout_reset(connection); 2492 return; 2493 } 2494 #ifdef ENABLE_LE_PERIPHERAL 2495 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2496 sm_key_t stk_flipped; 2497 reverse_128(setup->sm_ltk, stk_flipped); 2498 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2499 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2500 return; 2501 } 2502 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2503 sm_key_t ltk_flipped; 2504 reverse_128(setup->sm_ltk, ltk_flipped); 2505 connection->sm_engine_state = SM_RESPONDER_IDLE; 2506 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2507 return; 2508 } 2509 case SM_RESPONDER_PH4_Y_GET_ENC: 2510 // already busy? 2511 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2512 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2513 // Y = dm(DHK, Rand) 2514 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2515 sm_next_responding_state(connection); 2516 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2517 return; 2518 #endif 2519 #ifdef ENABLE_LE_CENTRAL 2520 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2521 sm_key_t stk_flipped; 2522 reverse_128(setup->sm_ltk, stk_flipped); 2523 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2524 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2525 return; 2526 } 2527 #endif 2528 2529 case SM_PH3_DISTRIBUTE_KEYS: 2530 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2531 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2532 uint8_t buffer[17]; 2533 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2534 reverse_128(setup->sm_ltk, &buffer[1]); 2535 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2536 sm_timeout_reset(connection); 2537 return; 2538 } 2539 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2540 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2541 uint8_t buffer[11]; 2542 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2543 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2544 reverse_64(setup->sm_local_rand, &buffer[3]); 2545 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2546 sm_timeout_reset(connection); 2547 return; 2548 } 2549 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2550 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2551 uint8_t buffer[17]; 2552 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2553 reverse_128(sm_persistent_irk, &buffer[1]); 2554 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2555 sm_timeout_reset(connection); 2556 return; 2557 } 2558 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2559 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2560 bd_addr_t local_address; 2561 uint8_t buffer[8]; 2562 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2563 gap_le_get_own_address(&buffer[1], local_address); 2564 reverse_bd_addr(local_address, &buffer[2]); 2565 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2566 sm_timeout_reset(connection); 2567 return; 2568 } 2569 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2570 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2571 2572 // hack to reproduce test runs 2573 if (test_use_fixed_local_csrk){ 2574 memset(setup->sm_local_csrk, 0xcc, 16); 2575 } 2576 2577 uint8_t buffer[17]; 2578 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2579 reverse_128(setup->sm_local_csrk, &buffer[1]); 2580 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2581 sm_timeout_reset(connection); 2582 return; 2583 } 2584 2585 // keys are sent 2586 if (IS_RESPONDER(connection->sm_role)){ 2587 // slave -> receive master keys if any 2588 if (sm_key_distribution_all_received(connection)){ 2589 sm_key_distribution_handle_all_received(connection); 2590 connection->sm_engine_state = SM_RESPONDER_IDLE; 2591 sm_done_for_handle(connection->sm_handle); 2592 } else { 2593 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2594 } 2595 } else { 2596 // master -> all done 2597 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2598 sm_done_for_handle(connection->sm_handle); 2599 } 2600 break; 2601 2602 default: 2603 break; 2604 } 2605 2606 // check again if active connection was released 2607 if (sm_active_connection) break; 2608 } 2609 } 2610 2611 // note: aes engine is ready as we just got the aes result 2612 static void sm_handle_encryption_result(uint8_t * data){ 2613 2614 sm_aes128_state = SM_AES128_IDLE; 2615 2616 if (sm_address_resolution_ah_calculation_active){ 2617 sm_address_resolution_ah_calculation_active = 0; 2618 // compare calulated address against connecting device 2619 uint8_t hash[3]; 2620 reverse_24(data, hash); 2621 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2622 log_info("LE Device Lookup: matched resolvable private address"); 2623 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2624 return; 2625 } 2626 // no match, try next 2627 sm_address_resolution_test++; 2628 return; 2629 } 2630 2631 switch (dkg_state){ 2632 case DKG_W4_IRK: 2633 reverse_128(data, sm_persistent_irk); 2634 log_info_key("irk", sm_persistent_irk); 2635 dkg_next_state(); 2636 return; 2637 case DKG_W4_DHK: 2638 reverse_128(data, sm_persistent_dhk); 2639 log_info_key("dhk", sm_persistent_dhk); 2640 dkg_next_state(); 2641 // SM Init Finished 2642 return; 2643 default: 2644 break; 2645 } 2646 2647 switch (rau_state){ 2648 case RAU_W4_ENC: 2649 reverse_24(data, &sm_random_address[3]); 2650 rau_next_state(); 2651 return; 2652 default: 2653 break; 2654 } 2655 2656 #ifdef ENABLE_CMAC_ENGINE 2657 switch (sm_cmac_state){ 2658 case CMAC_W4_SUBKEYS: 2659 case CMAC_W4_MI: 2660 case CMAC_W4_MLAST: 2661 { 2662 sm_key_t t; 2663 reverse_128(data, t); 2664 sm_cmac_handle_encryption_result(t); 2665 } 2666 return; 2667 default: 2668 break; 2669 } 2670 #endif 2671 2672 // retrieve sm_connection provided to sm_aes128_start_encryption 2673 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2674 if (!connection) return; 2675 switch (connection->sm_engine_state){ 2676 case SM_PH2_C1_W4_ENC_A: 2677 case SM_PH2_C1_W4_ENC_C: 2678 { 2679 sm_key_t t2; 2680 reverse_128(data, t2); 2681 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2682 } 2683 sm_next_responding_state(connection); 2684 return; 2685 case SM_PH2_C1_W4_ENC_B: 2686 reverse_128(data, setup->sm_local_confirm); 2687 log_info_key("c1!", setup->sm_local_confirm); 2688 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2689 return; 2690 case SM_PH2_C1_W4_ENC_D: 2691 { 2692 sm_key_t peer_confirm_test; 2693 reverse_128(data, peer_confirm_test); 2694 log_info_key("c1!", peer_confirm_test); 2695 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2696 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2697 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2698 return; 2699 } 2700 if (IS_RESPONDER(connection->sm_role)){ 2701 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2702 } else { 2703 connection->sm_engine_state = SM_PH2_CALC_STK; 2704 } 2705 } 2706 return; 2707 case SM_PH2_W4_STK: 2708 reverse_128(data, setup->sm_ltk); 2709 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2710 log_info_key("stk", setup->sm_ltk); 2711 if (IS_RESPONDER(connection->sm_role)){ 2712 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2713 } else { 2714 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2715 } 2716 return; 2717 case SM_PH3_Y_W4_ENC:{ 2718 sm_key_t y128; 2719 reverse_128(data, y128); 2720 setup->sm_local_y = big_endian_read_16(y128, 14); 2721 log_info_hex16("y", setup->sm_local_y); 2722 // PH3B3 - calculate EDIV 2723 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2724 log_info_hex16("ediv", setup->sm_local_ediv); 2725 // PH3B4 - calculate LTK - enc 2726 // LTK = d1(ER, DIV, 0)) 2727 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2728 return; 2729 } 2730 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2731 sm_key_t y128; 2732 reverse_128(data, y128); 2733 setup->sm_local_y = big_endian_read_16(y128, 14); 2734 log_info_hex16("y", setup->sm_local_y); 2735 2736 // PH3B3 - calculate DIV 2737 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2738 log_info_hex16("ediv", setup->sm_local_ediv); 2739 // PH3B4 - calculate LTK - enc 2740 // LTK = d1(ER, DIV, 0)) 2741 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2742 return; 2743 } 2744 case SM_PH3_LTK_W4_ENC: 2745 reverse_128(data, setup->sm_ltk); 2746 log_info_key("ltk", setup->sm_ltk); 2747 // calc CSRK next 2748 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2749 return; 2750 case SM_PH3_CSRK_W4_ENC: 2751 reverse_128(data, setup->sm_local_csrk); 2752 log_info_key("csrk", setup->sm_local_csrk); 2753 if (setup->sm_key_distribution_send_set){ 2754 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2755 } else { 2756 // no keys to send, just continue 2757 if (IS_RESPONDER(connection->sm_role)){ 2758 // slave -> receive master keys 2759 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2760 } else { 2761 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2762 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2763 } else { 2764 // master -> all done 2765 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2766 sm_done_for_handle(connection->sm_handle); 2767 } 2768 } 2769 } 2770 return; 2771 #ifdef ENABLE_LE_PERIPHERAL 2772 case SM_RESPONDER_PH4_LTK_W4_ENC: 2773 reverse_128(data, setup->sm_ltk); 2774 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2775 log_info_key("ltk", setup->sm_ltk); 2776 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2777 return; 2778 #endif 2779 default: 2780 break; 2781 } 2782 } 2783 2784 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2785 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 2786 #if !defined(WICED_VERSION) || defined(USE_MBEDTLS_FOR_ECDH) 2787 // @return OK 2788 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2789 if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; 2790 int offset = setup->sm_passkey_bit; 2791 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2792 while (size) { 2793 *buffer++ = setup->sm_peer_q[offset++]; 2794 size--; 2795 } 2796 setup->sm_passkey_bit = offset; 2797 return 1; 2798 } 2799 #endif 2800 #ifdef USE_MBEDTLS_FOR_ECDH 2801 // @return error 2802 static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ 2803 UNUSED(context); 2804 return sm_generate_f_rng(buffer, size) == 1; 2805 } 2806 #endif 2807 #endif 2808 #endif 2809 2810 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2811 static void sm_handle_random_result(uint8_t * data){ 2812 2813 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2814 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 2815 2816 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2817 int num_bytes = setup->sm_passkey_bit; 2818 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 2819 num_bytes += 8; 2820 setup->sm_passkey_bit = num_bytes; 2821 2822 if (num_bytes >= 64){ 2823 2824 // init pre-generated random data from sm_peer_q 2825 setup->sm_passkey_bit = 0; 2826 2827 // generate EC key 2828 #ifdef USE_MBEDTLS_FOR_ECDH 2829 mbedtls_mpi d; 2830 mbedtls_ecp_point P; 2831 mbedtls_mpi_init(&d); 2832 mbedtls_ecp_point_init(&P); 2833 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); 2834 log_info("gen keypair %x", res); 2835 mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); 2836 mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); 2837 mbedtls_mpi_write_binary(&d, ec_d, 32); 2838 mbedtls_ecp_point_free(&P); 2839 mbedtls_mpi_free(&d); 2840 #endif 2841 #ifdef USE_MICROECC_FOR_ECDH 2842 #ifndef WICED_VERSION 2843 // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default 2844 uECC_set_rng(&sm_generate_f_rng); 2845 #endif 2846 uECC_make_key(ec_q, ec_d); 2847 #endif 2848 2849 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2850 log_info("Elliptic curve: d"); 2851 log_info_hexdump(ec_d,32); 2852 sm_log_ec_keypair(); 2853 } 2854 } 2855 #endif 2856 #endif 2857 2858 switch (rau_state){ 2859 case RAU_W4_RANDOM: 2860 // non-resolvable vs. resolvable 2861 switch (gap_random_adress_type){ 2862 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2863 // resolvable: use random as prand and calc address hash 2864 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2865 memcpy(sm_random_address, data, 3); 2866 sm_random_address[0] &= 0x3f; 2867 sm_random_address[0] |= 0x40; 2868 rau_state = RAU_GET_ENC; 2869 break; 2870 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2871 default: 2872 // "The two most significant bits of the address shall be equal to ‘0’"" 2873 memcpy(sm_random_address, data, 6); 2874 sm_random_address[0] &= 0x3f; 2875 rau_state = RAU_SET_ADDRESS; 2876 break; 2877 } 2878 return; 2879 default: 2880 break; 2881 } 2882 2883 // retrieve sm_connection provided to sm_random_start 2884 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2885 if (!connection) return; 2886 switch (connection->sm_engine_state){ 2887 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2888 case SM_SC_W4_GET_RANDOM_A: 2889 memcpy(&setup->sm_local_nonce[0], data, 8); 2890 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2891 break; 2892 case SM_SC_W4_GET_RANDOM_B: 2893 memcpy(&setup->sm_local_nonce[8], data, 8); 2894 // initiator & jw/nc -> send pairing random 2895 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2896 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2897 break; 2898 } else { 2899 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2900 } 2901 break; 2902 #endif 2903 2904 case SM_PH2_W4_RANDOM_TK: 2905 { 2906 // map random to 0-999999 without speding much cycles on a modulus operation 2907 uint32_t tk = little_endian_read_32(data,0); 2908 tk = tk & 0xfffff; // 1048575 2909 if (tk >= 999999){ 2910 tk = tk - 999999; 2911 } 2912 sm_reset_tk(); 2913 big_endian_store_32(setup->sm_tk, 12, tk); 2914 if (IS_RESPONDER(connection->sm_role)){ 2915 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2916 } else { 2917 if (setup->sm_use_secure_connections){ 2918 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2919 } else { 2920 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2921 sm_trigger_user_response(connection); 2922 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2923 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2924 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2925 } 2926 } 2927 } 2928 return; 2929 } 2930 case SM_PH2_C1_W4_RANDOM_A: 2931 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2932 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2933 return; 2934 case SM_PH2_C1_W4_RANDOM_B: 2935 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2936 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2937 return; 2938 case SM_PH3_W4_RANDOM: 2939 reverse_64(data, setup->sm_local_rand); 2940 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2941 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2942 // no db for authenticated flag hack: store flag in bit 4 of LSB 2943 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2944 connection->sm_engine_state = SM_PH3_GET_DIV; 2945 return; 2946 case SM_PH3_W4_DIV: 2947 // use 16 bit from random value as div 2948 setup->sm_local_div = big_endian_read_16(data, 0); 2949 log_info_hex16("div", setup->sm_local_div); 2950 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2951 return; 2952 default: 2953 break; 2954 } 2955 } 2956 2957 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2958 2959 UNUSED(channel); 2960 UNUSED(size); 2961 2962 sm_connection_t * sm_conn; 2963 hci_con_handle_t con_handle; 2964 2965 switch (packet_type) { 2966 2967 case HCI_EVENT_PACKET: 2968 switch (hci_event_packet_get_type(packet)) { 2969 2970 case BTSTACK_EVENT_STATE: 2971 // bt stack activated, get started 2972 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2973 log_info("HCI Working!"); 2974 2975 // set local addr for le device db 2976 bd_addr_t local_bd_addr; 2977 gap_local_bd_addr(local_bd_addr); 2978 le_device_db_set_local_bd_addr(local_bd_addr); 2979 2980 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2981 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2982 if (!sm_have_ec_keypair){ 2983 setup->sm_passkey_bit = 0; 2984 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2985 } 2986 #endif 2987 // trigger Random Address generation if requested before 2988 switch (gap_random_adress_type){ 2989 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2990 rau_state = RAU_IDLE; 2991 break; 2992 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2993 rau_state = RAU_SET_ADDRESS; 2994 break; 2995 default: 2996 rau_state = RAU_GET_RANDOM; 2997 break; 2998 } 2999 sm_run(); 3000 } 3001 break; 3002 3003 case HCI_EVENT_LE_META: 3004 switch (packet[2]) { 3005 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3006 3007 log_info("sm: connected"); 3008 3009 if (packet[3]) return; // connection failed 3010 3011 con_handle = little_endian_read_16(packet, 4); 3012 sm_conn = sm_get_connection_for_handle(con_handle); 3013 if (!sm_conn) break; 3014 3015 sm_conn->sm_handle = con_handle; 3016 sm_conn->sm_role = packet[6]; 3017 sm_conn->sm_peer_addr_type = packet[7]; 3018 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3019 3020 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3021 3022 // reset security properties 3023 sm_conn->sm_connection_encrypted = 0; 3024 sm_conn->sm_connection_authenticated = 0; 3025 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3026 sm_conn->sm_le_db_index = -1; 3027 3028 // prepare CSRK lookup (does not involve setup) 3029 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3030 3031 // just connected -> everything else happens in sm_run() 3032 if (IS_RESPONDER(sm_conn->sm_role)){ 3033 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3034 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3035 if (sm_slave_request_security) { 3036 // request security if requested by app 3037 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3038 } else { 3039 // otherwise, wait for pairing request 3040 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3041 } 3042 } 3043 break; 3044 } else { 3045 // master 3046 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3047 } 3048 break; 3049 3050 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3051 con_handle = little_endian_read_16(packet, 3); 3052 sm_conn = sm_get_connection_for_handle(con_handle); 3053 if (!sm_conn) break; 3054 3055 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3056 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3057 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3058 break; 3059 } 3060 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3061 // PH2 SEND LTK as we need to exchange keys in PH3 3062 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3063 break; 3064 } 3065 3066 // store rand and ediv 3067 reverse_64(&packet[5], sm_conn->sm_local_rand); 3068 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3069 3070 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3071 // potentially stored LTK is from the master 3072 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3073 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3074 break; 3075 } 3076 3077 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3078 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3079 #else 3080 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3081 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3082 #endif 3083 break; 3084 3085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3086 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3087 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3088 log_error("Read Local P256 Public Key failed"); 3089 break; 3090 } 3091 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3092 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3093 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3094 sm_log_ec_keypair(); 3095 break; 3096 #endif 3097 default: 3098 break; 3099 } 3100 break; 3101 3102 case HCI_EVENT_ENCRYPTION_CHANGE: 3103 con_handle = little_endian_read_16(packet, 3); 3104 sm_conn = sm_get_connection_for_handle(con_handle); 3105 if (!sm_conn) break; 3106 3107 sm_conn->sm_connection_encrypted = packet[5]; 3108 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3109 sm_conn->sm_actual_encryption_key_size); 3110 log_info("event handler, state %u", sm_conn->sm_engine_state); 3111 if (!sm_conn->sm_connection_encrypted) break; 3112 // continue if part of initial pairing 3113 switch (sm_conn->sm_engine_state){ 3114 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3115 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3116 sm_done_for_handle(sm_conn->sm_handle); 3117 break; 3118 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3119 if (IS_RESPONDER(sm_conn->sm_role)){ 3120 // slave 3121 if (setup->sm_use_secure_connections){ 3122 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3123 } else { 3124 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3125 } 3126 } else { 3127 // master 3128 if (sm_key_distribution_all_received(sm_conn)){ 3129 // skip receiving keys as there are none 3130 sm_key_distribution_handle_all_received(sm_conn); 3131 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3132 } else { 3133 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3134 } 3135 } 3136 break; 3137 default: 3138 break; 3139 } 3140 break; 3141 3142 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3143 con_handle = little_endian_read_16(packet, 3); 3144 sm_conn = sm_get_connection_for_handle(con_handle); 3145 if (!sm_conn) break; 3146 3147 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3148 log_info("event handler, state %u", sm_conn->sm_engine_state); 3149 // continue if part of initial pairing 3150 switch (sm_conn->sm_engine_state){ 3151 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3152 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3153 sm_done_for_handle(sm_conn->sm_handle); 3154 break; 3155 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3156 if (IS_RESPONDER(sm_conn->sm_role)){ 3157 // slave 3158 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3159 } else { 3160 // master 3161 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3162 } 3163 break; 3164 default: 3165 break; 3166 } 3167 break; 3168 3169 3170 case HCI_EVENT_DISCONNECTION_COMPLETE: 3171 con_handle = little_endian_read_16(packet, 3); 3172 sm_done_for_handle(con_handle); 3173 sm_conn = sm_get_connection_for_handle(con_handle); 3174 if (!sm_conn) break; 3175 3176 // delete stored bonding on disconnect with authentication failure in ph0 3177 if (sm_conn->sm_role == 0 3178 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3179 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3180 le_device_db_remove(sm_conn->sm_le_db_index); 3181 } 3182 3183 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3184 sm_conn->sm_handle = 0; 3185 break; 3186 3187 case HCI_EVENT_COMMAND_COMPLETE: 3188 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3189 sm_handle_encryption_result(&packet[6]); 3190 break; 3191 } 3192 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3193 sm_handle_random_result(&packet[6]); 3194 break; 3195 } 3196 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3197 // Hack for Nordic nRF5 series that doesn't have public address: 3198 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3199 // - we use this as default for advertisements/connections 3200 if (hci_get_manufacturer() == BLUETOOTH_COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3201 log_info("nRF5: using (fake) public address as random static address"); 3202 bd_addr_t addr; 3203 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3204 gap_random_address_set(addr); 3205 } 3206 } 3207 break; 3208 default: 3209 break; 3210 } 3211 break; 3212 default: 3213 break; 3214 } 3215 3216 sm_run(); 3217 } 3218 3219 static inline int sm_calc_actual_encryption_key_size(int other){ 3220 if (other < sm_min_encryption_key_size) return 0; 3221 if (other < sm_max_encryption_key_size) return other; 3222 return sm_max_encryption_key_size; 3223 } 3224 3225 3226 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3227 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3228 switch (method){ 3229 case JUST_WORKS: 3230 case NK_BOTH_INPUT: 3231 return 1; 3232 default: 3233 return 0; 3234 } 3235 } 3236 // responder 3237 3238 static int sm_passkey_used(stk_generation_method_t method){ 3239 switch (method){ 3240 case PK_RESP_INPUT: 3241 return 1; 3242 default: 3243 return 0; 3244 } 3245 } 3246 #endif 3247 3248 /** 3249 * @return ok 3250 */ 3251 static int sm_validate_stk_generation_method(void){ 3252 // check if STK generation method is acceptable by client 3253 switch (setup->sm_stk_generation_method){ 3254 case JUST_WORKS: 3255 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3256 case PK_RESP_INPUT: 3257 case PK_INIT_INPUT: 3258 case OK_BOTH_INPUT: 3259 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3260 case OOB: 3261 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3262 case NK_BOTH_INPUT: 3263 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3264 return 1; 3265 default: 3266 return 0; 3267 } 3268 } 3269 3270 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3271 3272 UNUSED(size); 3273 3274 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3275 sm_run(); 3276 } 3277 3278 if (packet_type != SM_DATA_PACKET) return; 3279 3280 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3281 if (!sm_conn) return; 3282 3283 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3284 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3285 return; 3286 } 3287 3288 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3289 3290 int err; 3291 UNUSED(err); 3292 3293 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3294 uint8_t buffer[5]; 3295 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3296 buffer[1] = 3; 3297 little_endian_store_16(buffer, 2, con_handle); 3298 buffer[4] = packet[1]; 3299 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3300 return; 3301 } 3302 3303 switch (sm_conn->sm_engine_state){ 3304 3305 // a sm timeout requries a new physical connection 3306 case SM_GENERAL_TIMEOUT: 3307 return; 3308 3309 #ifdef ENABLE_LE_CENTRAL 3310 3311 // Initiator 3312 case SM_INITIATOR_CONNECTED: 3313 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3314 sm_pdu_received_in_wrong_state(sm_conn); 3315 break; 3316 } 3317 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3318 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3319 break; 3320 } 3321 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3322 sm_key_t ltk; 3323 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3324 if (!sm_is_null_key(ltk)){ 3325 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3326 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3327 } else { 3328 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3329 } 3330 break; 3331 } 3332 // otherwise, store security request 3333 sm_conn->sm_security_request_received = 1; 3334 break; 3335 3336 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3337 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3338 sm_pdu_received_in_wrong_state(sm_conn); 3339 break; 3340 } 3341 // store pairing request 3342 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3343 err = sm_stk_generation_init(sm_conn); 3344 if (err){ 3345 setup->sm_pairing_failed_reason = err; 3346 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3347 break; 3348 } 3349 3350 // generate random number first, if we need to show passkey 3351 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3352 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3353 break; 3354 } 3355 3356 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3357 if (setup->sm_use_secure_connections){ 3358 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3359 if (setup->sm_stk_generation_method == JUST_WORKS){ 3360 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3361 sm_trigger_user_response(sm_conn); 3362 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3363 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3364 } 3365 } else { 3366 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3367 } 3368 break; 3369 } 3370 #endif 3371 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3372 sm_trigger_user_response(sm_conn); 3373 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3374 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3375 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3376 } 3377 break; 3378 3379 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3380 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3381 sm_pdu_received_in_wrong_state(sm_conn); 3382 break; 3383 } 3384 3385 // store s_confirm 3386 reverse_128(&packet[1], setup->sm_peer_confirm); 3387 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3388 break; 3389 3390 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3391 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3392 sm_pdu_received_in_wrong_state(sm_conn); 3393 break;; 3394 } 3395 3396 // received random value 3397 reverse_128(&packet[1], setup->sm_peer_random); 3398 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3399 break; 3400 #endif 3401 3402 #ifdef ENABLE_LE_PERIPHERAL 3403 // Responder 3404 case SM_RESPONDER_IDLE: 3405 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3406 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3407 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3408 sm_pdu_received_in_wrong_state(sm_conn); 3409 break;; 3410 } 3411 3412 // store pairing request 3413 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3414 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3415 break; 3416 #endif 3417 3418 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3419 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3420 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3421 sm_pdu_received_in_wrong_state(sm_conn); 3422 break; 3423 } 3424 3425 // store public key for DH Key calculation 3426 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3427 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3428 3429 // validate public key 3430 err = 0; 3431 3432 #ifdef USE_MBEDTLS_FOR_ECDH 3433 mbedtls_ecp_point Q; 3434 mbedtls_ecp_point_init( &Q ); 3435 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); 3436 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 3437 mbedtls_mpi_lset(&Q.Z, 1); 3438 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3439 mbedtls_ecp_point_free( & Q); 3440 #endif 3441 #ifdef USE_MICROECC_FOR_ECDH 3442 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3443 #endif 3444 3445 if (err){ 3446 log_error("sm: peer public key invalid %x", err); 3447 // uses "unspecified reason", there is no "public key invalid" error code 3448 sm_pdu_received_in_wrong_state(sm_conn); 3449 break; 3450 } 3451 3452 if (IS_RESPONDER(sm_conn->sm_role)){ 3453 // responder 3454 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3455 } else { 3456 // initiator 3457 // stk generation method 3458 // passkey entry: notify app to show passkey or to request passkey 3459 switch (setup->sm_stk_generation_method){ 3460 case JUST_WORKS: 3461 case NK_BOTH_INPUT: 3462 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3463 break; 3464 case PK_RESP_INPUT: 3465 sm_sc_start_calculating_local_confirm(sm_conn); 3466 break; 3467 case PK_INIT_INPUT: 3468 case OK_BOTH_INPUT: 3469 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3470 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3471 break; 3472 } 3473 sm_sc_start_calculating_local_confirm(sm_conn); 3474 break; 3475 case OOB: 3476 // TODO: implement SC OOB 3477 break; 3478 } 3479 } 3480 break; 3481 3482 case SM_SC_W4_CONFIRMATION: 3483 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3484 sm_pdu_received_in_wrong_state(sm_conn); 3485 break; 3486 } 3487 // received confirm value 3488 reverse_128(&packet[1], setup->sm_peer_confirm); 3489 3490 if (IS_RESPONDER(sm_conn->sm_role)){ 3491 // responder 3492 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3493 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3494 // still waiting for passkey 3495 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3496 break; 3497 } 3498 } 3499 sm_sc_start_calculating_local_confirm(sm_conn); 3500 } else { 3501 // initiator 3502 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3503 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3504 } else { 3505 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3506 } 3507 } 3508 break; 3509 3510 case SM_SC_W4_PAIRING_RANDOM: 3511 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3512 sm_pdu_received_in_wrong_state(sm_conn); 3513 break; 3514 } 3515 3516 // received random value 3517 reverse_128(&packet[1], setup->sm_peer_nonce); 3518 3519 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3520 // only check for JUST WORK/NC in initiator role AND passkey entry 3521 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3522 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3523 } 3524 3525 sm_sc_state_after_receiving_random(sm_conn); 3526 break; 3527 3528 case SM_SC_W2_CALCULATE_G2: 3529 case SM_SC_W4_CALCULATE_G2: 3530 case SM_SC_W2_CALCULATE_F5_SALT: 3531 case SM_SC_W4_CALCULATE_F5_SALT: 3532 case SM_SC_W2_CALCULATE_F5_MACKEY: 3533 case SM_SC_W4_CALCULATE_F5_MACKEY: 3534 case SM_SC_W2_CALCULATE_F5_LTK: 3535 case SM_SC_W4_CALCULATE_F5_LTK: 3536 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3537 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3538 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3539 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3540 sm_pdu_received_in_wrong_state(sm_conn); 3541 break; 3542 } 3543 // store DHKey Check 3544 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3545 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3546 3547 // have we been only waiting for dhkey check command? 3548 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3549 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3550 } 3551 break; 3552 #endif 3553 3554 #ifdef ENABLE_LE_PERIPHERAL 3555 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3556 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3557 sm_pdu_received_in_wrong_state(sm_conn); 3558 break; 3559 } 3560 3561 // received confirm value 3562 reverse_128(&packet[1], setup->sm_peer_confirm); 3563 3564 // notify client to hide shown passkey 3565 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3566 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3567 } 3568 3569 // handle user cancel pairing? 3570 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3571 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3572 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3573 break; 3574 } 3575 3576 // wait for user action? 3577 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3578 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3579 break; 3580 } 3581 3582 // calculate and send local_confirm 3583 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3584 break; 3585 3586 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3587 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3588 sm_pdu_received_in_wrong_state(sm_conn); 3589 break;; 3590 } 3591 3592 // received random value 3593 reverse_128(&packet[1], setup->sm_peer_random); 3594 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3595 break; 3596 #endif 3597 3598 case SM_PH3_RECEIVE_KEYS: 3599 switch(packet[0]){ 3600 case SM_CODE_ENCRYPTION_INFORMATION: 3601 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3602 reverse_128(&packet[1], setup->sm_peer_ltk); 3603 break; 3604 3605 case SM_CODE_MASTER_IDENTIFICATION: 3606 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3607 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3608 reverse_64(&packet[3], setup->sm_peer_rand); 3609 break; 3610 3611 case SM_CODE_IDENTITY_INFORMATION: 3612 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3613 reverse_128(&packet[1], setup->sm_peer_irk); 3614 break; 3615 3616 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3617 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3618 setup->sm_peer_addr_type = packet[1]; 3619 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3620 break; 3621 3622 case SM_CODE_SIGNING_INFORMATION: 3623 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3624 reverse_128(&packet[1], setup->sm_peer_csrk); 3625 break; 3626 default: 3627 // Unexpected PDU 3628 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3629 break; 3630 } 3631 // done with key distribution? 3632 if (sm_key_distribution_all_received(sm_conn)){ 3633 3634 sm_key_distribution_handle_all_received(sm_conn); 3635 3636 if (IS_RESPONDER(sm_conn->sm_role)){ 3637 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3638 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3639 } else { 3640 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3641 sm_done_for_handle(sm_conn->sm_handle); 3642 } 3643 } else { 3644 if (setup->sm_use_secure_connections){ 3645 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3646 } else { 3647 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3648 } 3649 } 3650 } 3651 break; 3652 default: 3653 // Unexpected PDU 3654 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3655 break; 3656 } 3657 3658 // try to send preparared packet 3659 sm_run(); 3660 } 3661 3662 // Security Manager Client API 3663 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3664 sm_get_oob_data = get_oob_data_callback; 3665 } 3666 3667 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3668 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3669 } 3670 3671 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3672 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3673 } 3674 3675 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3676 sm_min_encryption_key_size = min_size; 3677 sm_max_encryption_key_size = max_size; 3678 } 3679 3680 void sm_set_authentication_requirements(uint8_t auth_req){ 3681 sm_auth_req = auth_req; 3682 } 3683 3684 void sm_set_io_capabilities(io_capability_t io_capability){ 3685 sm_io_capabilities = io_capability; 3686 } 3687 3688 #ifdef ENABLE_LE_PERIPHERAL 3689 void sm_set_request_security(int enable){ 3690 sm_slave_request_security = enable; 3691 } 3692 #endif 3693 3694 void sm_set_er(sm_key_t er){ 3695 memcpy(sm_persistent_er, er, 16); 3696 } 3697 3698 void sm_set_ir(sm_key_t ir){ 3699 memcpy(sm_persistent_ir, ir, 16); 3700 } 3701 3702 // Testing support only 3703 void sm_test_set_irk(sm_key_t irk){ 3704 memcpy(sm_persistent_irk, irk, 16); 3705 sm_persistent_irk_ready = 1; 3706 } 3707 3708 void sm_test_use_fixed_local_csrk(void){ 3709 test_use_fixed_local_csrk = 1; 3710 } 3711 3712 void sm_init(void){ 3713 // set some (BTstack default) ER and IR 3714 int i; 3715 sm_key_t er; 3716 sm_key_t ir; 3717 for (i=0;i<16;i++){ 3718 er[i] = 0x30 + i; 3719 ir[i] = 0x90 + i; 3720 } 3721 sm_set_er(er); 3722 sm_set_ir(ir); 3723 // defaults 3724 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3725 | SM_STK_GENERATION_METHOD_OOB 3726 | SM_STK_GENERATION_METHOD_PASSKEY 3727 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3728 3729 sm_max_encryption_key_size = 16; 3730 sm_min_encryption_key_size = 7; 3731 3732 #ifdef ENABLE_CMAC_ENGINE 3733 sm_cmac_state = CMAC_IDLE; 3734 #endif 3735 dkg_state = DKG_W4_WORKING; 3736 rau_state = RAU_W4_WORKING; 3737 sm_aes128_state = SM_AES128_IDLE; 3738 sm_address_resolution_test = -1; // no private address to resolve yet 3739 sm_address_resolution_ah_calculation_active = 0; 3740 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3741 sm_address_resolution_general_queue = NULL; 3742 3743 gap_random_adress_update_period = 15 * 60 * 1000L; 3744 sm_active_connection = 0; 3745 3746 test_use_fixed_local_csrk = 0; 3747 3748 // register for HCI Events from HCI 3749 hci_event_callback_registration.callback = &sm_event_packet_handler; 3750 hci_add_event_handler(&hci_event_callback_registration); 3751 3752 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3753 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3754 3755 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3756 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3757 #endif 3758 3759 #ifdef USE_MBEDTLS_FOR_ECDH 3760 #ifndef HAVE_MALLOC 3761 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3762 #endif 3763 mbedtls_ecp_group_init(&mbedtls_ec_group); 3764 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3765 #endif 3766 } 3767 3768 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3769 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3770 memcpy(&ec_q[0], qx, 32); 3771 memcpy(&ec_q[32], qy, 32); 3772 memcpy(ec_d, d, 32); 3773 sm_have_ec_keypair = 1; 3774 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3775 #else 3776 UNUSED(qx); 3777 UNUSED(qy); 3778 UNUSED(d); 3779 #endif 3780 } 3781 3782 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3783 #ifndef USE_MBEDTLS_FOR_ECDH 3784 static void parse_hex(uint8_t * buffer, const char * hex_string){ 3785 while (*hex_string){ 3786 int high_nibble = nibble_for_char(*hex_string++); 3787 int low_nibble = nibble_for_char(*hex_string++); 3788 *buffer++ = (high_nibble << 4) | low_nibble; 3789 } 3790 } 3791 #endif 3792 #endif 3793 3794 void sm_test_use_fixed_ec_keypair(void){ 3795 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3796 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 3797 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 3798 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 3799 #ifdef USE_MBEDTLS_FOR_ECDH 3800 // use test keypair from spec 3801 mbedtls_mpi x; 3802 mbedtls_mpi_init(&x); 3803 mbedtls_mpi_read_string( &x, 16, ec_d_string); 3804 mbedtls_mpi_write_binary(&x, ec_d, 32); 3805 mbedtls_mpi_read_string( &x, 16, ec_qx_string); 3806 mbedtls_mpi_write_binary(&x, &ec_q[0], 32); 3807 mbedtls_mpi_read_string( &x, 16, ec_qy_string); 3808 mbedtls_mpi_write_binary(&x, &ec_q[32], 32); 3809 mbedtls_mpi_free(&x); 3810 #else 3811 parse_hex(ec_d, ec_d_string); 3812 parse_hex(&ec_q[0], ec_qx_string); 3813 parse_hex(&ec_q[32], ec_qy_string); 3814 #endif 3815 sm_have_ec_keypair = 1; 3816 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3817 #endif 3818 } 3819 3820 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3821 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3822 if (!hci_con) return NULL; 3823 return &hci_con->sm_connection; 3824 } 3825 3826 // @returns 0 if not encrypted, 7-16 otherwise 3827 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3828 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3829 if (!sm_conn) return 0; // wrong connection 3830 if (!sm_conn->sm_connection_encrypted) return 0; 3831 return sm_conn->sm_actual_encryption_key_size; 3832 } 3833 3834 int sm_authenticated(hci_con_handle_t con_handle){ 3835 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3836 if (!sm_conn) return 0; // wrong connection 3837 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3838 return sm_conn->sm_connection_authenticated; 3839 } 3840 3841 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3842 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3843 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3844 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3845 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3846 return sm_conn->sm_connection_authorization_state; 3847 } 3848 3849 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3850 switch (sm_conn->sm_engine_state){ 3851 case SM_GENERAL_IDLE: 3852 case SM_RESPONDER_IDLE: 3853 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3854 sm_run(); 3855 break; 3856 default: 3857 break; 3858 } 3859 } 3860 3861 /** 3862 * @brief Trigger Security Request 3863 */ 3864 void sm_send_security_request(hci_con_handle_t con_handle){ 3865 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3866 if (!sm_conn) return; 3867 sm_send_security_request_for_connection(sm_conn); 3868 } 3869 3870 // request pairing 3871 void sm_request_pairing(hci_con_handle_t con_handle){ 3872 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3873 if (!sm_conn) return; // wrong connection 3874 3875 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3876 if (IS_RESPONDER(sm_conn->sm_role)){ 3877 sm_send_security_request_for_connection(sm_conn); 3878 } else { 3879 // used as a trigger to start central/master/initiator security procedures 3880 uint16_t ediv; 3881 sm_key_t ltk; 3882 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3883 switch (sm_conn->sm_irk_lookup_state){ 3884 case IRK_LOOKUP_FAILED: 3885 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3886 break; 3887 case IRK_LOOKUP_SUCCEEDED: 3888 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3889 if (!sm_is_null_key(ltk) || ediv){ 3890 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3891 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3892 } else { 3893 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3894 } 3895 break; 3896 default: 3897 sm_conn->sm_bonding_requested = 1; 3898 break; 3899 } 3900 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3901 sm_conn->sm_bonding_requested = 1; 3902 } 3903 } 3904 sm_run(); 3905 } 3906 3907 // called by client app on authorization request 3908 void sm_authorization_decline(hci_con_handle_t con_handle){ 3909 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3910 if (!sm_conn) return; // wrong connection 3911 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3912 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3913 } 3914 3915 void sm_authorization_grant(hci_con_handle_t con_handle){ 3916 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3917 if (!sm_conn) return; // wrong connection 3918 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3919 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3920 } 3921 3922 // GAP Bonding API 3923 3924 void sm_bonding_decline(hci_con_handle_t con_handle){ 3925 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3926 if (!sm_conn) return; // wrong connection 3927 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3928 3929 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3930 switch (setup->sm_stk_generation_method){ 3931 case PK_RESP_INPUT: 3932 case PK_INIT_INPUT: 3933 case OK_BOTH_INPUT: 3934 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3935 break; 3936 case NK_BOTH_INPUT: 3937 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3938 break; 3939 case JUST_WORKS: 3940 case OOB: 3941 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3942 break; 3943 } 3944 } 3945 sm_run(); 3946 } 3947 3948 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3949 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3950 if (!sm_conn) return; // wrong connection 3951 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3952 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3953 if (setup->sm_use_secure_connections){ 3954 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3955 } else { 3956 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3957 } 3958 } 3959 3960 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3961 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3962 sm_sc_prepare_dhkey_check(sm_conn); 3963 } 3964 #endif 3965 3966 sm_run(); 3967 } 3968 3969 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3970 // for now, it's the same 3971 sm_just_works_confirm(con_handle); 3972 } 3973 3974 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3975 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3976 if (!sm_conn) return; // wrong connection 3977 sm_reset_tk(); 3978 big_endian_store_32(setup->sm_tk, 12, passkey); 3979 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3980 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3981 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3982 } 3983 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3984 memcpy(setup->sm_ra, setup->sm_tk, 16); 3985 memcpy(setup->sm_rb, setup->sm_tk, 16); 3986 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3987 sm_sc_start_calculating_local_confirm(sm_conn); 3988 } 3989 #endif 3990 sm_run(); 3991 } 3992 3993 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3994 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3995 if (!sm_conn) return; // wrong connection 3996 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3997 setup->sm_keypress_notification = action; 3998 sm_run(); 3999 } 4000 4001 /** 4002 * @brief Identify device in LE Device DB 4003 * @param handle 4004 * @returns index from le_device_db or -1 if not found/identified 4005 */ 4006 int sm_le_device_index(hci_con_handle_t con_handle ){ 4007 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4008 if (!sm_conn) return -1; 4009 return sm_conn->sm_le_db_index; 4010 } 4011 4012 static int gap_random_address_type_requires_updates(void){ 4013 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4014 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 4015 return 1; 4016 } 4017 4018 static uint8_t own_address_type(void){ 4019 switch (gap_random_adress_type){ 4020 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4021 return BD_ADDR_TYPE_LE_PUBLIC; 4022 default: 4023 return BD_ADDR_TYPE_LE_RANDOM; 4024 } 4025 } 4026 4027 // GAP LE API 4028 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4029 gap_random_address_update_stop(); 4030 gap_random_adress_type = random_address_type; 4031 hci_le_set_own_address_type(own_address_type()); 4032 if (!gap_random_address_type_requires_updates()) return; 4033 gap_random_address_update_start(); 4034 gap_random_address_trigger(); 4035 } 4036 4037 gap_random_address_type_t gap_random_address_get_mode(void){ 4038 return gap_random_adress_type; 4039 } 4040 4041 void gap_random_address_set_update_period(int period_ms){ 4042 gap_random_adress_update_period = period_ms; 4043 if (!gap_random_address_type_requires_updates()) return; 4044 gap_random_address_update_stop(); 4045 gap_random_address_update_start(); 4046 } 4047 4048 void gap_random_address_set(bd_addr_t addr){ 4049 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4050 memcpy(sm_random_address, addr, 6); 4051 if (rau_state == RAU_W4_WORKING) return; 4052 rau_state = RAU_SET_ADDRESS; 4053 sm_run(); 4054 } 4055 4056 #ifdef ENABLE_LE_PERIPHERAL 4057 /* 4058 * @brief Set Advertisement Paramters 4059 * @param adv_int_min 4060 * @param adv_int_max 4061 * @param adv_type 4062 * @param direct_address_type 4063 * @param direct_address 4064 * @param channel_map 4065 * @param filter_policy 4066 * 4067 * @note own_address_type is used from gap_random_address_set_mode 4068 */ 4069 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4070 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4071 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4072 direct_address_typ, direct_address, channel_map, filter_policy); 4073 } 4074 #endif 4075 4076