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 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 75 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 76 #else 77 #define USE_MBEDTLS_FOR_ECDH 78 #endif 79 #endif 80 81 // Software ECDH implementation provided by mbedtls 82 #ifdef USE_MBEDTLS_FOR_ECDH 83 #include "mbedtls/config.h" 84 #include "mbedtls/platform.h" 85 #include "mbedtls/ecp.h" 86 #include "sm_mbedtls_allocator.h" 87 #endif 88 89 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 90 #define ENABLE_CMAC_ENGINE 91 #endif 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_W4_IRK, 101 DKG_CALC_DHK, 102 DKG_W4_DHK, 103 DKG_READY 104 } derived_key_generation_t; 105 106 typedef enum { 107 RAU_W4_WORKING, 108 RAU_IDLE, 109 RAU_GET_RANDOM, 110 RAU_W4_RANDOM, 111 RAU_GET_ENC, 112 RAU_W4_ENC, 113 RAU_SET_ADDRESS, 114 } random_address_update_t; 115 116 typedef enum { 117 CMAC_IDLE, 118 CMAC_CALC_SUBKEYS, 119 CMAC_W4_SUBKEYS, 120 CMAC_CALC_MI, 121 CMAC_W4_MI, 122 CMAC_CALC_MLAST, 123 CMAC_W4_MLAST 124 } cmac_state_t; 125 126 typedef enum { 127 JUST_WORKS, 128 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 129 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 130 OK_BOTH_INPUT, // Only input on both, both input PK 131 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 132 OOB // OOB available on both sides 133 } stk_generation_method_t; 134 135 typedef enum { 136 SM_USER_RESPONSE_IDLE, 137 SM_USER_RESPONSE_PENDING, 138 SM_USER_RESPONSE_CONFIRM, 139 SM_USER_RESPONSE_PASSKEY, 140 SM_USER_RESPONSE_DECLINE 141 } sm_user_response_t; 142 143 typedef enum { 144 SM_AES128_IDLE, 145 SM_AES128_ACTIVE 146 } sm_aes128_state_t; 147 148 typedef enum { 149 ADDRESS_RESOLUTION_IDLE, 150 ADDRESS_RESOLUTION_GENERAL, 151 ADDRESS_RESOLUTION_FOR_CONNECTION, 152 } address_resolution_mode_t; 153 154 typedef enum { 155 ADDRESS_RESOLUTION_SUCEEDED, 156 ADDRESS_RESOLUTION_FAILED, 157 } address_resolution_event_t; 158 159 typedef enum { 160 EC_KEY_GENERATION_IDLE, 161 EC_KEY_GENERATION_ACTIVE, 162 EC_KEY_GENERATION_W4_KEY, 163 EC_KEY_GENERATION_DONE, 164 } ec_key_generation_state_t; 165 166 typedef enum { 167 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 168 } sm_state_var_t; 169 170 // 171 // GLOBAL DATA 172 // 173 174 static uint8_t test_use_fixed_local_csrk; 175 176 // configuration 177 static uint8_t sm_accepted_stk_generation_methods; 178 static uint8_t sm_max_encryption_key_size; 179 static uint8_t sm_min_encryption_key_size; 180 static uint8_t sm_auth_req = 0; 181 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 182 static uint8_t sm_slave_request_security; 183 #ifdef ENABLE_LE_SECURE_CONNECTIONS 184 static uint8_t sm_have_ec_keypair; 185 #endif 186 187 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 188 static sm_key_t sm_persistent_er; 189 static sm_key_t sm_persistent_ir; 190 191 // derived from sm_persistent_ir 192 static sm_key_t sm_persistent_dhk; 193 static sm_key_t sm_persistent_irk; 194 static uint8_t sm_persistent_irk_ready = 0; // used for testing 195 static derived_key_generation_t dkg_state; 196 197 // derived from sm_persistent_er 198 // .. 199 200 // random address update 201 static random_address_update_t rau_state; 202 static bd_addr_t sm_random_address; 203 204 // CMAC Calculation: General 205 #ifdef ENABLE_CMAC_ENGINE 206 static cmac_state_t sm_cmac_state; 207 static uint16_t sm_cmac_message_len; 208 static sm_key_t sm_cmac_k; 209 static sm_key_t sm_cmac_x; 210 static sm_key_t sm_cmac_m_last; 211 static uint8_t sm_cmac_block_current; 212 static uint8_t sm_cmac_block_count; 213 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 214 static void (*sm_cmac_done_handler)(uint8_t * hash); 215 #endif 216 217 // CMAC for ATT Signed Writes 218 #ifdef ENABLE_LE_SIGNED_WRITE 219 static uint8_t sm_cmac_header[3]; 220 static const uint8_t * sm_cmac_message; 221 static uint8_t sm_cmac_sign_counter[4]; 222 #endif 223 224 // CMAC for Secure Connection functions 225 #ifdef ENABLE_LE_SECURE_CONNECTIONS 226 static sm_connection_t * sm_cmac_connection; 227 static uint8_t sm_cmac_sc_buffer[80]; 228 #endif 229 230 // resolvable private address lookup / CSRK calculation 231 static int sm_address_resolution_test; 232 static int sm_address_resolution_ah_calculation_active; 233 static uint8_t sm_address_resolution_addr_type; 234 static bd_addr_t sm_address_resolution_address; 235 static void * sm_address_resolution_context; 236 static address_resolution_mode_t sm_address_resolution_mode; 237 static btstack_linked_list_t sm_address_resolution_general_queue; 238 239 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 240 static sm_aes128_state_t sm_aes128_state; 241 static void * sm_aes128_context; 242 243 // random engine. store context (ususally sm_connection_t) 244 static void * sm_random_context; 245 246 // to receive hci events 247 static btstack_packet_callback_registration_t hci_event_callback_registration; 248 249 /* to dispatch sm event */ 250 static btstack_linked_list_t sm_event_handlers; 251 252 // LE Secure Connections 253 #ifdef ENABLE_LE_SECURE_CONNECTIONS 254 static ec_key_generation_state_t ec_key_generation_state; 255 static uint8_t ec_d[32]; 256 static uint8_t ec_qx[32]; 257 static uint8_t ec_qy[32]; 258 #endif 259 260 // Software ECDH implementation provided by mbedtls 261 #ifdef USE_MBEDTLS_FOR_ECDH 262 // group is always valid 263 static mbedtls_ecp_group mbedtls_ec_group; 264 #ifndef HAVE_MALLOC 265 // COMP Method with Window 2 266 // 1300 bytes with 23 allocations 267 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 268 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 269 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 270 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 271 #endif 272 #endif 273 274 // 275 // Volume 3, Part H, Chapter 24 276 // "Security shall be initiated by the Security Manager in the device in the master role. 277 // The device in the slave role shall be the responding device." 278 // -> master := initiator, slave := responder 279 // 280 281 // data needed for security setup 282 typedef struct sm_setup_context { 283 284 btstack_timer_source_t sm_timeout; 285 286 // used in all phases 287 uint8_t sm_pairing_failed_reason; 288 289 // user response, (Phase 1 and/or 2) 290 uint8_t sm_user_response; 291 uint8_t sm_keypress_notification; 292 293 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 294 int sm_key_distribution_send_set; 295 int sm_key_distribution_received_set; 296 297 // Phase 2 (Pairing over SMP) 298 stk_generation_method_t sm_stk_generation_method; 299 sm_key_t sm_tk; 300 uint8_t sm_use_secure_connections; 301 302 sm_key_t sm_c1_t3_value; // c1 calculation 303 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 304 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 305 sm_key_t sm_local_random; 306 sm_key_t sm_local_confirm; 307 sm_key_t sm_peer_random; 308 sm_key_t sm_peer_confirm; 309 uint8_t sm_m_addr_type; // address and type can be removed 310 uint8_t sm_s_addr_type; // '' 311 bd_addr_t sm_m_address; // '' 312 bd_addr_t sm_s_address; // '' 313 sm_key_t sm_ltk; 314 315 uint8_t sm_state_vars; 316 #ifdef ENABLE_LE_SECURE_CONNECTIONS 317 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 318 uint8_t sm_peer_qy[32]; // '' 319 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 320 sm_key_t sm_local_nonce; // might be combined with sm_local_random 321 sm_key_t sm_peer_dhkey_check; 322 sm_key_t sm_local_dhkey_check; 323 sm_key_t sm_ra; 324 sm_key_t sm_rb; 325 sm_key_t sm_t; // used for f5 and h6 326 sm_key_t sm_mackey; 327 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 328 #endif 329 330 // Phase 3 331 332 // key distribution, we generate 333 uint16_t sm_local_y; 334 uint16_t sm_local_div; 335 uint16_t sm_local_ediv; 336 uint8_t sm_local_rand[8]; 337 sm_key_t sm_local_ltk; 338 sm_key_t sm_local_csrk; 339 sm_key_t sm_local_irk; 340 // sm_local_address/addr_type not needed 341 342 // key distribution, received from peer 343 uint16_t sm_peer_y; 344 uint16_t sm_peer_div; 345 uint16_t sm_peer_ediv; 346 uint8_t sm_peer_rand[8]; 347 sm_key_t sm_peer_ltk; 348 sm_key_t sm_peer_irk; 349 sm_key_t sm_peer_csrk; 350 uint8_t sm_peer_addr_type; 351 bd_addr_t sm_peer_address; 352 353 } sm_setup_context_t; 354 355 // 356 static sm_setup_context_t the_setup; 357 static sm_setup_context_t * setup = &the_setup; 358 359 // active connection - the one for which the_setup is used for 360 static uint16_t sm_active_connection = 0; 361 362 // @returns 1 if oob data is available 363 // stores oob data in provided 16 byte buffer if not null 364 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 365 366 // horizontal: initiator capabilities 367 // vertial: responder capabilities 368 static const stk_generation_method_t stk_generation_method [5] [5] = { 369 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 370 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 371 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 372 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 373 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 374 }; 375 376 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 377 #ifdef ENABLE_LE_SECURE_CONNECTIONS 378 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 379 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 380 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 381 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 382 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 383 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 384 }; 385 #endif 386 387 static void sm_run(void); 388 static void sm_done_for_handle(hci_con_handle_t con_handle); 389 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 390 static inline int sm_calc_actual_encryption_key_size(int other); 391 static int sm_validate_stk_generation_method(void); 392 393 static void log_info_hex16(const char * name, uint16_t value){ 394 log_info("%-6s 0x%04x", name, value); 395 } 396 397 // @returns 1 if all bytes are 0 398 static int sm_is_null(uint8_t * data, int size){ 399 int i; 400 for (i=0; i < size ; i++){ 401 if (data[i]) return 0; 402 } 403 return 1; 404 } 405 406 static int sm_is_null_random(uint8_t random[8]){ 407 return sm_is_null(random, 8); 408 } 409 410 static int sm_is_null_key(uint8_t * key){ 411 return sm_is_null(key, 16); 412 } 413 414 // Key utils 415 static void sm_reset_tk(void){ 416 int i; 417 for (i=0;i<16;i++){ 418 setup->sm_tk[i] = 0; 419 } 420 } 421 422 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 423 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 424 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 425 int i; 426 for (i = max_encryption_size ; i < 16 ; i++){ 427 key[15-i] = 0; 428 } 429 } 430 431 // SMP Timeout implementation 432 433 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 434 // the Security Manager Timer shall be reset and started. 435 // 436 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 437 // 438 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 439 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 440 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 441 // established. 442 443 static void sm_timeout_handler(btstack_timer_source_t * timer){ 444 log_info("SM timeout"); 445 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 446 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 447 sm_done_for_handle(sm_conn->sm_handle); 448 449 // trigger handling of next ready connection 450 sm_run(); 451 } 452 static void sm_timeout_start(sm_connection_t * sm_conn){ 453 btstack_run_loop_remove_timer(&setup->sm_timeout); 454 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 455 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 456 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 457 btstack_run_loop_add_timer(&setup->sm_timeout); 458 } 459 static void sm_timeout_stop(void){ 460 btstack_run_loop_remove_timer(&setup->sm_timeout); 461 } 462 static void sm_timeout_reset(sm_connection_t * sm_conn){ 463 sm_timeout_stop(); 464 sm_timeout_start(sm_conn); 465 } 466 467 // end of sm timeout 468 469 // GAP Random Address updates 470 static gap_random_address_type_t gap_random_adress_type; 471 static btstack_timer_source_t gap_random_address_update_timer; 472 static uint32_t gap_random_adress_update_period; 473 474 static void gap_random_address_trigger(void){ 475 if (rau_state != RAU_IDLE) return; 476 log_info("gap_random_address_trigger"); 477 rau_state = RAU_GET_RANDOM; 478 sm_run(); 479 } 480 481 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 482 UNUSED(timer); 483 484 log_info("GAP Random Address Update due"); 485 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 486 btstack_run_loop_add_timer(&gap_random_address_update_timer); 487 gap_random_address_trigger(); 488 } 489 490 static void gap_random_address_update_start(void){ 491 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 492 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 493 btstack_run_loop_add_timer(&gap_random_address_update_timer); 494 } 495 496 static void gap_random_address_update_stop(void){ 497 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 498 } 499 500 501 static void sm_random_start(void * context){ 502 sm_random_context = context; 503 hci_send_cmd(&hci_le_rand); 504 } 505 506 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 507 // context is made availabe to aes128 result handler by this 508 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 509 sm_aes128_state = SM_AES128_ACTIVE; 510 sm_key_t key_flipped, plaintext_flipped; 511 reverse_128(key, key_flipped); 512 reverse_128(plaintext, plaintext_flipped); 513 sm_aes128_context = context; 514 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 515 } 516 517 // ah(k,r) helper 518 // r = padding || r 519 // r - 24 bit value 520 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 521 // r'= padding || r 522 memset(r_prime, 0, 16); 523 memcpy(&r_prime[13], r, 3); 524 } 525 526 // d1 helper 527 // d' = padding || r || d 528 // d,r - 16 bit values 529 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 530 // d'= padding || r || d 531 memset(d1_prime, 0, 16); 532 big_endian_store_16(d1_prime, 12, r); 533 big_endian_store_16(d1_prime, 14, d); 534 } 535 536 // dm helper 537 // r’ = padding || r 538 // r - 64 bit value 539 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 540 memset(r_prime, 0, 16); 541 memcpy(&r_prime[8], r, 8); 542 } 543 544 // calculate arguments for first AES128 operation in C1 function 545 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){ 546 547 // p1 = pres || preq || rat’ || iat’ 548 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 549 // cant octet of pres becomes the most significant octet of p1. 550 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 551 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 552 // p1 is 0x05000800000302070710000001010001." 553 554 sm_key_t p1; 555 reverse_56(pres, &p1[0]); 556 reverse_56(preq, &p1[7]); 557 p1[14] = rat; 558 p1[15] = iat; 559 log_info_key("p1", p1); 560 log_info_key("r", r); 561 562 // t1 = r xor p1 563 int i; 564 for (i=0;i<16;i++){ 565 t1[i] = r[i] ^ p1[i]; 566 } 567 log_info_key("t1", t1); 568 } 569 570 // calculate arguments for second AES128 operation in C1 function 571 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 572 // p2 = padding || ia || ra 573 // "The least significant octet of ra becomes the least significant octet of p2 and 574 // the most significant octet of padding becomes the most significant octet of p2. 575 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 576 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 577 578 sm_key_t p2; 579 memset(p2, 0, 16); 580 memcpy(&p2[4], ia, 6); 581 memcpy(&p2[10], ra, 6); 582 log_info_key("p2", p2); 583 584 // c1 = e(k, t2_xor_p2) 585 int i; 586 for (i=0;i<16;i++){ 587 t3[i] = t2[i] ^ p2[i]; 588 } 589 log_info_key("t3", t3); 590 } 591 592 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 593 log_info_key("r1", r1); 594 log_info_key("r2", r2); 595 memcpy(&r_prime[8], &r2[8], 8); 596 memcpy(&r_prime[0], &r1[8], 8); 597 } 598 599 #ifdef ENABLE_LE_SECURE_CONNECTIONS 600 // Software implementations of crypto toolbox for LE Secure Connection 601 // TODO: replace with code to use AES Engine of HCI Controller 602 typedef uint8_t sm_key24_t[3]; 603 typedef uint8_t sm_key56_t[7]; 604 typedef uint8_t sm_key256_t[32]; 605 606 #if 0 607 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 608 uint32_t rk[RKLENGTH(KEYBITS)]; 609 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 610 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 611 } 612 613 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 614 memcpy(k1, k0, 16); 615 sm_shift_left_by_one_bit_inplace(16, k1); 616 if (k0[0] & 0x80){ 617 k1[15] ^= 0x87; 618 } 619 memcpy(k2, k1, 16); 620 sm_shift_left_by_one_bit_inplace(16, k2); 621 if (k1[0] & 0x80){ 622 k2[15] ^= 0x87; 623 } 624 } 625 626 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 627 sm_key_t k0, k1, k2, zero; 628 memset(zero, 0, 16); 629 630 aes128_calc_cyphertext(key, zero, k0); 631 calc_subkeys(k0, k1, k2); 632 633 int cmac_block_count = (cmac_message_len + 15) / 16; 634 635 // step 3: .. 636 if (cmac_block_count==0){ 637 cmac_block_count = 1; 638 } 639 640 // step 4: set m_last 641 sm_key_t cmac_m_last; 642 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 643 int i; 644 if (sm_cmac_last_block_complete){ 645 for (i=0;i<16;i++){ 646 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 647 } 648 } else { 649 int valid_octets_in_last_block = cmac_message_len & 0x0f; 650 for (i=0;i<16;i++){ 651 if (i < valid_octets_in_last_block){ 652 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 653 continue; 654 } 655 if (i == valid_octets_in_last_block){ 656 cmac_m_last[i] = 0x80 ^ k2[i]; 657 continue; 658 } 659 cmac_m_last[i] = k2[i]; 660 } 661 } 662 663 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 664 // LOG_KEY(cmac_m_last); 665 666 // Step 5 667 sm_key_t cmac_x; 668 memset(cmac_x, 0, 16); 669 670 // Step 6 671 sm_key_t sm_cmac_y; 672 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 673 for (i=0;i<16;i++){ 674 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 675 } 676 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 677 } 678 for (i=0;i<16;i++){ 679 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 680 } 681 682 // Step 7 683 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 684 } 685 #endif 686 #endif 687 688 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){ 689 event[0] = type; 690 event[1] = event_size - 2; 691 little_endian_store_16(event, 2, con_handle); 692 event[4] = addr_type; 693 reverse_bd_addr(address, &event[5]); 694 } 695 696 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 697 UNUSED(channel); 698 699 // log event 700 hci_dump_packet(packet_type, 1, packet, size); 701 // dispatch to all event handlers 702 btstack_linked_list_iterator_t it; 703 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 704 while (btstack_linked_list_iterator_has_next(&it)){ 705 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 706 entry->callback(packet_type, 0, packet, size); 707 } 708 } 709 710 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 711 uint8_t event[11]; 712 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 713 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 714 } 715 716 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){ 717 uint8_t event[15]; 718 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 719 little_endian_store_32(event, 11, passkey); 720 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 721 } 722 723 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){ 724 // fetch addr and addr type from db 725 bd_addr_t identity_address; 726 int identity_address_type; 727 le_device_db_info(index, &identity_address_type, identity_address, NULL); 728 729 uint8_t event[19]; 730 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 731 event[11] = identity_address_type; 732 reverse_bd_addr(identity_address, &event[12]); 733 event[18] = index; 734 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 735 } 736 737 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){ 738 739 uint8_t event[18]; 740 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 741 event[11] = result; 742 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 743 } 744 745 // decide on stk generation based on 746 // - pairing request 747 // - io capabilities 748 // - OOB data availability 749 static void sm_setup_tk(void){ 750 751 // default: just works 752 setup->sm_stk_generation_method = JUST_WORKS; 753 754 #ifdef ENABLE_LE_SECURE_CONNECTIONS 755 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 756 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 757 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 758 memset(setup->sm_ra, 0, 16); 759 memset(setup->sm_rb, 0, 16); 760 #else 761 setup->sm_use_secure_connections = 0; 762 #endif 763 764 // If both devices have not set the MITM option in the Authentication Requirements 765 // Flags, then the IO capabilities shall be ignored and the Just Works association 766 // model shall be used. 767 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 768 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 769 log_info("SM: MITM not required by both -> JUST WORKS"); 770 return; 771 } 772 773 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 774 775 // If both devices have out of band authentication data, then the Authentication 776 // Requirements Flags shall be ignored when selecting the pairing method and the 777 // Out of Band pairing method shall be used. 778 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 779 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 780 log_info("SM: have OOB data"); 781 log_info_key("OOB", setup->sm_tk); 782 setup->sm_stk_generation_method = OOB; 783 return; 784 } 785 786 // Reset TK as it has been setup in sm_init_setup 787 sm_reset_tk(); 788 789 // Also use just works if unknown io capabilites 790 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)){ 791 return; 792 } 793 794 // Otherwise the IO capabilities of the devices shall be used to determine the 795 // pairing method as defined in Table 2.4. 796 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 797 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 798 799 #ifdef ENABLE_LE_SECURE_CONNECTIONS 800 // table not define by default 801 if (setup->sm_use_secure_connections){ 802 generation_method = stk_generation_method_with_secure_connection; 803 } 804 #endif 805 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)]; 806 807 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 808 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); 809 } 810 811 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 812 int flags = 0; 813 if (key_set & SM_KEYDIST_ENC_KEY){ 814 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 815 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 816 } 817 if (key_set & SM_KEYDIST_ID_KEY){ 818 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 819 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 820 } 821 if (key_set & SM_KEYDIST_SIGN){ 822 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 823 } 824 return flags; 825 } 826 827 static void sm_setup_key_distribution(uint8_t key_set){ 828 setup->sm_key_distribution_received_set = 0; 829 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 830 } 831 832 // CSRK Key Lookup 833 834 835 static int sm_address_resolution_idle(void){ 836 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 837 } 838 839 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){ 840 memcpy(sm_address_resolution_address, addr, 6); 841 sm_address_resolution_addr_type = addr_type; 842 sm_address_resolution_test = 0; 843 sm_address_resolution_mode = mode; 844 sm_address_resolution_context = context; 845 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 846 } 847 848 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 849 // check if already in list 850 btstack_linked_list_iterator_t it; 851 sm_lookup_entry_t * entry; 852 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 853 while(btstack_linked_list_iterator_has_next(&it)){ 854 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 855 if (entry->address_type != address_type) continue; 856 if (memcmp(entry->address, address, 6)) continue; 857 // already in list 858 return BTSTACK_BUSY; 859 } 860 entry = btstack_memory_sm_lookup_entry_get(); 861 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 862 entry->address_type = (bd_addr_type_t) address_type; 863 memcpy(entry->address, address, 6); 864 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 865 sm_run(); 866 return 0; 867 } 868 869 // 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 870 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 871 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 872 } 873 static inline void dkg_next_state(void){ 874 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 875 } 876 static inline void rau_next_state(void){ 877 rau_state = (random_address_update_t) (((int)rau_state) + 1); 878 } 879 880 // CMAC calculation using AES Engine 881 #ifdef ENABLE_CMAC_ENGINE 882 883 static inline void sm_cmac_next_state(void){ 884 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 885 } 886 887 static int sm_cmac_last_block_complete(void){ 888 if (sm_cmac_message_len == 0) return 0; 889 return (sm_cmac_message_len & 0x0f) == 0; 890 } 891 892 int sm_cmac_ready(void){ 893 return sm_cmac_state == CMAC_IDLE; 894 } 895 896 // generic cmac calculation 897 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])){ 898 // Generalized CMAC 899 memcpy(sm_cmac_k, key, 16); 900 memset(sm_cmac_x, 0, 16); 901 sm_cmac_block_current = 0; 902 sm_cmac_message_len = message_len; 903 sm_cmac_done_handler = done_callback; 904 sm_cmac_get_byte = get_byte_callback; 905 906 // step 2: n := ceil(len/const_Bsize); 907 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 908 909 // step 3: .. 910 if (sm_cmac_block_count==0){ 911 sm_cmac_block_count = 1; 912 } 913 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 914 915 // first, we need to compute l for k1, k2, and m_last 916 sm_cmac_state = CMAC_CALC_SUBKEYS; 917 918 // let's go 919 sm_run(); 920 } 921 #endif 922 923 // cmac for ATT Message signing 924 #ifdef ENABLE_LE_SIGNED_WRITE 925 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 926 if (offset >= sm_cmac_message_len) { 927 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 928 return 0; 929 } 930 931 offset = sm_cmac_message_len - 1 - offset; 932 933 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 934 if (offset < 3){ 935 return sm_cmac_header[offset]; 936 } 937 int actual_message_len_incl_header = sm_cmac_message_len - 4; 938 if (offset < actual_message_len_incl_header){ 939 return sm_cmac_message[offset - 3]; 940 } 941 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 942 } 943 944 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)){ 945 // ATT Message Signing 946 sm_cmac_header[0] = opcode; 947 little_endian_store_16(sm_cmac_header, 1, con_handle); 948 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 949 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 950 sm_cmac_message = message; 951 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 952 } 953 #endif 954 955 #ifdef ENABLE_CMAC_ENGINE 956 static void sm_cmac_handle_aes_engine_ready(void){ 957 switch (sm_cmac_state){ 958 case CMAC_CALC_SUBKEYS: { 959 sm_key_t const_zero; 960 memset(const_zero, 0, 16); 961 sm_cmac_next_state(); 962 sm_aes128_start(sm_cmac_k, const_zero, NULL); 963 break; 964 } 965 case CMAC_CALC_MI: { 966 int j; 967 sm_key_t y; 968 for (j=0;j<16;j++){ 969 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 970 } 971 sm_cmac_block_current++; 972 sm_cmac_next_state(); 973 sm_aes128_start(sm_cmac_k, y, NULL); 974 break; 975 } 976 case CMAC_CALC_MLAST: { 977 int i; 978 sm_key_t y; 979 for (i=0;i<16;i++){ 980 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 981 } 982 log_info_key("Y", y); 983 sm_cmac_block_current++; 984 sm_cmac_next_state(); 985 sm_aes128_start(sm_cmac_k, y, NULL); 986 break; 987 } 988 default: 989 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 990 break; 991 } 992 } 993 994 // CMAC Implementation using AES128 engine 995 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 996 int i; 997 int carry = 0; 998 for (i=len-1; i >= 0 ; i--){ 999 int new_carry = data[i] >> 7; 1000 data[i] = data[i] << 1 | carry; 1001 carry = new_carry; 1002 } 1003 } 1004 1005 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1006 switch (sm_cmac_state){ 1007 case CMAC_W4_SUBKEYS: { 1008 sm_key_t k1; 1009 memcpy(k1, data, 16); 1010 sm_shift_left_by_one_bit_inplace(16, k1); 1011 if (data[0] & 0x80){ 1012 k1[15] ^= 0x87; 1013 } 1014 sm_key_t k2; 1015 memcpy(k2, k1, 16); 1016 sm_shift_left_by_one_bit_inplace(16, k2); 1017 if (k1[0] & 0x80){ 1018 k2[15] ^= 0x87; 1019 } 1020 1021 log_info_key("k", sm_cmac_k); 1022 log_info_key("k1", k1); 1023 log_info_key("k2", k2); 1024 1025 // step 4: set m_last 1026 int i; 1027 if (sm_cmac_last_block_complete()){ 1028 for (i=0;i<16;i++){ 1029 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1030 } 1031 } else { 1032 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1033 for (i=0;i<16;i++){ 1034 if (i < valid_octets_in_last_block){ 1035 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1036 continue; 1037 } 1038 if (i == valid_octets_in_last_block){ 1039 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1040 continue; 1041 } 1042 sm_cmac_m_last[i] = k2[i]; 1043 } 1044 } 1045 1046 // next 1047 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1048 break; 1049 } 1050 case CMAC_W4_MI: 1051 memcpy(sm_cmac_x, data, 16); 1052 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1053 break; 1054 case CMAC_W4_MLAST: 1055 // done 1056 log_info("Setting CMAC Engine to IDLE"); 1057 sm_cmac_state = CMAC_IDLE; 1058 log_info_key("CMAC", data); 1059 sm_cmac_done_handler(data); 1060 break; 1061 default: 1062 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1063 break; 1064 } 1065 } 1066 #endif 1067 1068 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1069 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1070 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1071 switch (setup->sm_stk_generation_method){ 1072 case PK_RESP_INPUT: 1073 if (IS_RESPONDER(sm_conn->sm_role)){ 1074 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1075 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1076 } else { 1077 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)); 1078 } 1079 break; 1080 case PK_INIT_INPUT: 1081 if (IS_RESPONDER(sm_conn->sm_role)){ 1082 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)); 1083 } else { 1084 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1085 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1086 } 1087 break; 1088 case OK_BOTH_INPUT: 1089 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1090 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1091 break; 1092 case NK_BOTH_INPUT: 1093 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1094 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)); 1095 break; 1096 case JUST_WORKS: 1097 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1098 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1099 break; 1100 case OOB: 1101 // client already provided OOB data, let's skip notification. 1102 break; 1103 } 1104 } 1105 1106 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1107 int recv_flags; 1108 if (IS_RESPONDER(sm_conn->sm_role)){ 1109 // slave / responder 1110 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1111 } else { 1112 // master / initiator 1113 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1114 } 1115 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1116 return recv_flags == setup->sm_key_distribution_received_set; 1117 } 1118 1119 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1120 if (sm_active_connection == con_handle){ 1121 sm_timeout_stop(); 1122 sm_active_connection = 0; 1123 log_info("sm: connection 0x%x released setup context", con_handle); 1124 } 1125 } 1126 1127 static int sm_key_distribution_flags_for_auth_req(void){ 1128 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1129 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1130 // encryption information only if bonding requested 1131 flags |= SM_KEYDIST_ENC_KEY; 1132 } 1133 return flags; 1134 } 1135 1136 static void sm_reset_setup(void){ 1137 // fill in sm setup 1138 setup->sm_state_vars = 0; 1139 setup->sm_keypress_notification = 0xff; 1140 sm_reset_tk(); 1141 } 1142 1143 static void sm_init_setup(sm_connection_t * sm_conn){ 1144 1145 // fill in sm setup 1146 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1147 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1148 1149 // query client for OOB data 1150 int have_oob_data = 0; 1151 if (sm_get_oob_data) { 1152 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1153 } 1154 1155 sm_pairing_packet_t * local_packet; 1156 if (IS_RESPONDER(sm_conn->sm_role)){ 1157 // slave 1158 local_packet = &setup->sm_s_pres; 1159 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1160 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1161 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1162 } else { 1163 // master 1164 local_packet = &setup->sm_m_preq; 1165 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1166 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1167 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1168 1169 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1170 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1171 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1172 } 1173 1174 uint8_t auth_req = sm_auth_req; 1175 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1176 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1177 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1178 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1179 } 1180 1181 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1182 1183 sm_pairing_packet_t * remote_packet; 1184 int remote_key_request; 1185 if (IS_RESPONDER(sm_conn->sm_role)){ 1186 // slave / responder 1187 remote_packet = &setup->sm_m_preq; 1188 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1189 } else { 1190 // master / initiator 1191 remote_packet = &setup->sm_s_pres; 1192 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1193 } 1194 1195 // check key size 1196 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1197 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1198 1199 // decide on STK generation method 1200 sm_setup_tk(); 1201 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1202 1203 // check if STK generation method is acceptable by client 1204 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1205 1206 // identical to responder 1207 sm_setup_key_distribution(remote_key_request); 1208 1209 // JUST WORKS doens't provide authentication 1210 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1211 1212 return 0; 1213 } 1214 1215 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1216 1217 // cache and reset context 1218 int matched_device_id = sm_address_resolution_test; 1219 address_resolution_mode_t mode = sm_address_resolution_mode; 1220 void * context = sm_address_resolution_context; 1221 1222 // reset context 1223 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1224 sm_address_resolution_context = NULL; 1225 sm_address_resolution_test = -1; 1226 hci_con_handle_t con_handle = 0; 1227 1228 sm_connection_t * sm_connection; 1229 #ifdef ENABLE_LE_CENTRAL 1230 sm_key_t ltk; 1231 #endif 1232 switch (mode){ 1233 case ADDRESS_RESOLUTION_GENERAL: 1234 break; 1235 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1236 sm_connection = (sm_connection_t *) context; 1237 con_handle = sm_connection->sm_handle; 1238 switch (event){ 1239 case ADDRESS_RESOLUTION_SUCEEDED: 1240 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1241 sm_connection->sm_le_db_index = matched_device_id; 1242 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1243 #ifdef ENABLE_LE_CENTRAL 1244 if (sm_connection->sm_role) break; 1245 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1246 sm_connection->sm_security_request_received = 0; 1247 sm_connection->sm_bonding_requested = 0; 1248 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1249 if (!sm_is_null_key(ltk)){ 1250 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1251 } else { 1252 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1253 } 1254 #endif 1255 break; 1256 case ADDRESS_RESOLUTION_FAILED: 1257 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1258 #ifdef ENABLE_LE_CENTRAL 1259 if (sm_connection->sm_role) break; 1260 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1261 sm_connection->sm_security_request_received = 0; 1262 sm_connection->sm_bonding_requested = 0; 1263 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1264 #endif 1265 break; 1266 } 1267 break; 1268 default: 1269 break; 1270 } 1271 1272 switch (event){ 1273 case ADDRESS_RESOLUTION_SUCEEDED: 1274 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1275 break; 1276 case ADDRESS_RESOLUTION_FAILED: 1277 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1278 break; 1279 } 1280 } 1281 1282 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1283 1284 int le_db_index = -1; 1285 1286 // lookup device based on IRK 1287 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1288 int i; 1289 for (i=0; i < le_device_db_count(); i++){ 1290 sm_key_t irk; 1291 bd_addr_t address; 1292 int address_type; 1293 le_device_db_info(i, &address_type, address, irk); 1294 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1295 log_info("sm: device found for IRK, updating"); 1296 le_db_index = i; 1297 break; 1298 } 1299 } 1300 } 1301 1302 // if not found, lookup via public address if possible 1303 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1304 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1305 int i; 1306 for (i=0; i < le_device_db_count(); i++){ 1307 bd_addr_t address; 1308 int address_type; 1309 le_device_db_info(i, &address_type, address, NULL); 1310 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1311 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1312 log_info("sm: device found for public address, updating"); 1313 le_db_index = i; 1314 break; 1315 } 1316 } 1317 } 1318 1319 // if not found, add to db 1320 if (le_db_index < 0) { 1321 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1322 } 1323 1324 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1325 1326 if (le_db_index >= 0){ 1327 1328 #ifdef ENABLE_LE_SIGNED_WRITE 1329 // store local CSRK 1330 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1331 log_info("sm: store local CSRK"); 1332 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1333 le_device_db_local_counter_set(le_db_index, 0); 1334 } 1335 1336 // store remote CSRK 1337 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1338 log_info("sm: store remote CSRK"); 1339 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1340 le_device_db_remote_counter_set(le_db_index, 0); 1341 } 1342 #endif 1343 // store encryption information for secure connections: LTK generated by ECDH 1344 if (setup->sm_use_secure_connections){ 1345 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1346 uint8_t zero_rand[8]; 1347 memset(zero_rand, 0, 8); 1348 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1349 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1350 } 1351 1352 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1353 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1354 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1355 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1356 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1357 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1358 1359 } 1360 } 1361 1362 // keep le_db_index 1363 sm_conn->sm_le_db_index = le_db_index; 1364 } 1365 1366 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1367 setup->sm_pairing_failed_reason = reason; 1368 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1369 } 1370 1371 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1372 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1373 } 1374 1375 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1376 1377 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1378 static int sm_passkey_used(stk_generation_method_t method); 1379 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1380 1381 static void sm_log_ec_keypair(void){ 1382 log_info("Elliptic curve: X"); 1383 log_info_hexdump(ec_qx,32); 1384 log_info("Elliptic curve: Y"); 1385 log_info_hexdump(ec_qy,32); 1386 } 1387 1388 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1389 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1390 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1391 } else { 1392 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1393 } 1394 } 1395 1396 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1397 if (IS_RESPONDER(sm_conn->sm_role)){ 1398 // Responder 1399 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1400 } else { 1401 // Initiator role 1402 switch (setup->sm_stk_generation_method){ 1403 case JUST_WORKS: 1404 sm_sc_prepare_dhkey_check(sm_conn); 1405 break; 1406 1407 case NK_BOTH_INPUT: 1408 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1409 break; 1410 case PK_INIT_INPUT: 1411 case PK_RESP_INPUT: 1412 case OK_BOTH_INPUT: 1413 if (setup->sm_passkey_bit < 20) { 1414 sm_sc_start_calculating_local_confirm(sm_conn); 1415 } else { 1416 sm_sc_prepare_dhkey_check(sm_conn); 1417 } 1418 break; 1419 case OOB: 1420 // TODO: implement SC OOB 1421 break; 1422 } 1423 } 1424 } 1425 1426 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1427 return sm_cmac_sc_buffer[offset]; 1428 } 1429 1430 static void sm_sc_cmac_done(uint8_t * hash){ 1431 log_info("sm_sc_cmac_done: "); 1432 log_info_hexdump(hash, 16); 1433 1434 sm_connection_t * sm_conn = sm_cmac_connection; 1435 sm_cmac_connection = NULL; 1436 link_key_type_t link_key_type; 1437 1438 switch (sm_conn->sm_engine_state){ 1439 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1440 memcpy(setup->sm_local_confirm, hash, 16); 1441 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1442 break; 1443 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1444 // check 1445 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1446 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1447 break; 1448 } 1449 sm_sc_state_after_receiving_random(sm_conn); 1450 break; 1451 case SM_SC_W4_CALCULATE_G2: { 1452 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1453 big_endian_store_32(setup->sm_tk, 12, vab); 1454 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1455 sm_trigger_user_response(sm_conn); 1456 break; 1457 } 1458 case SM_SC_W4_CALCULATE_F5_SALT: 1459 memcpy(setup->sm_t, hash, 16); 1460 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1461 break; 1462 case SM_SC_W4_CALCULATE_F5_MACKEY: 1463 memcpy(setup->sm_mackey, hash, 16); 1464 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1465 break; 1466 case SM_SC_W4_CALCULATE_F5_LTK: 1467 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1468 // Errata Service Release to the Bluetooth Specification: ESR09 1469 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1470 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1471 memcpy(setup->sm_ltk, hash, 16); 1472 memcpy(setup->sm_local_ltk, hash, 16); 1473 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1474 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1475 break; 1476 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1477 memcpy(setup->sm_local_dhkey_check, hash, 16); 1478 if (IS_RESPONDER(sm_conn->sm_role)){ 1479 // responder 1480 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1481 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1482 } else { 1483 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1484 } 1485 } else { 1486 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1487 } 1488 break; 1489 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1490 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1491 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1492 break; 1493 } 1494 if (IS_RESPONDER(sm_conn->sm_role)){ 1495 // responder 1496 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1497 } else { 1498 // initiator 1499 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1500 } 1501 break; 1502 case SM_SC_W4_CALCULATE_H6_ILK: 1503 memcpy(setup->sm_t, hash, 16); 1504 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1505 break; 1506 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1507 reverse_128(hash, setup->sm_t); 1508 link_key_type = sm_conn->sm_connection_authenticated ? 1509 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1510 if (IS_RESPONDER(sm_conn->sm_role)){ 1511 #ifdef ENABLE_CLASSIC 1512 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1513 #endif 1514 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1515 } else { 1516 #ifdef ENABLE_CLASSIC 1517 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1518 #endif 1519 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1520 } 1521 sm_done_for_handle(sm_conn->sm_handle); 1522 break; 1523 default: 1524 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1525 break; 1526 } 1527 sm_run(); 1528 } 1529 1530 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){ 1531 const uint16_t message_len = 65; 1532 sm_cmac_connection = sm_conn; 1533 memcpy(sm_cmac_sc_buffer, u, 32); 1534 memcpy(sm_cmac_sc_buffer+32, v, 32); 1535 sm_cmac_sc_buffer[64] = z; 1536 log_info("f4 key"); 1537 log_info_hexdump(x, 16); 1538 log_info("f4 message"); 1539 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1540 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1541 } 1542 1543 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1544 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1545 static const uint8_t f5_length[] = { 0x01, 0x00}; 1546 1547 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1548 #ifdef USE_MBEDTLS_FOR_ECDH 1549 // da * Pb 1550 mbedtls_mpi d; 1551 mbedtls_ecp_point Q; 1552 mbedtls_ecp_point DH; 1553 mbedtls_mpi_init(&d); 1554 mbedtls_ecp_point_init(&Q); 1555 mbedtls_ecp_point_init(&DH); 1556 mbedtls_mpi_read_binary(&d, ec_d, 32); 1557 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1558 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1559 mbedtls_mpi_lset(&Q.Z, 1); 1560 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1561 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1562 mbedtls_ecp_point_free(&DH); 1563 mbedtls_mpi_free(&d); 1564 mbedtls_ecp_point_free(&Q); 1565 #endif 1566 log_info("dhkey"); 1567 log_info_hexdump(dhkey, 32); 1568 } 1569 1570 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1571 // calculate DHKEY 1572 sm_key256_t dhkey; 1573 sm_sc_calculate_dhkey(dhkey); 1574 1575 // calculate salt for f5 1576 const uint16_t message_len = 32; 1577 sm_cmac_connection = sm_conn; 1578 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1579 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1580 } 1581 1582 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){ 1583 const uint16_t message_len = 53; 1584 sm_cmac_connection = sm_conn; 1585 1586 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1587 sm_cmac_sc_buffer[0] = 0; 1588 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1589 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1590 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1591 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1592 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1593 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1594 log_info("f5 key"); 1595 log_info_hexdump(t, 16); 1596 log_info("f5 message for MacKey"); 1597 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1598 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1599 } 1600 1601 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1602 sm_key56_t bd_addr_master, bd_addr_slave; 1603 bd_addr_master[0] = setup->sm_m_addr_type; 1604 bd_addr_slave[0] = setup->sm_s_addr_type; 1605 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1606 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1607 if (IS_RESPONDER(sm_conn->sm_role)){ 1608 // responder 1609 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1610 } else { 1611 // initiator 1612 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1613 } 1614 } 1615 1616 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1617 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1618 const uint16_t message_len = 53; 1619 sm_cmac_connection = sm_conn; 1620 sm_cmac_sc_buffer[0] = 1; 1621 // 1..52 setup before 1622 log_info("f5 key"); 1623 log_info_hexdump(t, 16); 1624 log_info("f5 message for LTK"); 1625 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1626 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1627 } 1628 1629 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1630 f5_ltk(sm_conn, setup->sm_t); 1631 } 1632 1633 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){ 1634 const uint16_t message_len = 65; 1635 sm_cmac_connection = sm_conn; 1636 memcpy(sm_cmac_sc_buffer, n1, 16); 1637 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1638 memcpy(sm_cmac_sc_buffer+32, r, 16); 1639 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1640 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1641 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1642 log_info("f6 key"); 1643 log_info_hexdump(w, 16); 1644 log_info("f6 message"); 1645 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1646 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1647 } 1648 1649 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1650 // - U is 256 bits 1651 // - V is 256 bits 1652 // - X is 128 bits 1653 // - Y is 128 bits 1654 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){ 1655 const uint16_t message_len = 80; 1656 sm_cmac_connection = sm_conn; 1657 memcpy(sm_cmac_sc_buffer, u, 32); 1658 memcpy(sm_cmac_sc_buffer+32, v, 32); 1659 memcpy(sm_cmac_sc_buffer+64, y, 16); 1660 log_info("g2 key"); 1661 log_info_hexdump(x, 16); 1662 log_info("g2 message"); 1663 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1664 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1665 } 1666 1667 static void g2_calculate(sm_connection_t * sm_conn) { 1668 // calc Va if numeric comparison 1669 if (IS_RESPONDER(sm_conn->sm_role)){ 1670 // responder 1671 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1672 } else { 1673 // initiator 1674 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1675 } 1676 } 1677 1678 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1679 uint8_t z = 0; 1680 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1681 // some form of passkey 1682 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1683 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1684 setup->sm_passkey_bit++; 1685 } 1686 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1687 } 1688 1689 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1690 uint8_t z = 0; 1691 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1692 // some form of passkey 1693 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1694 // sm_passkey_bit was increased before sending confirm value 1695 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1696 } 1697 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1698 } 1699 1700 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1701 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1702 } 1703 1704 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1705 // calculate DHKCheck 1706 sm_key56_t bd_addr_master, bd_addr_slave; 1707 bd_addr_master[0] = setup->sm_m_addr_type; 1708 bd_addr_slave[0] = setup->sm_s_addr_type; 1709 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1710 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1711 uint8_t iocap_a[3]; 1712 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1713 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1714 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1715 uint8_t iocap_b[3]; 1716 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1717 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1718 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1719 if (IS_RESPONDER(sm_conn->sm_role)){ 1720 // responder 1721 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); 1722 } else { 1723 // initiator 1724 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); 1725 } 1726 } 1727 1728 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1729 // validate E = f6() 1730 sm_key56_t bd_addr_master, bd_addr_slave; 1731 bd_addr_master[0] = setup->sm_m_addr_type; 1732 bd_addr_slave[0] = setup->sm_s_addr_type; 1733 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1734 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1735 1736 uint8_t iocap_a[3]; 1737 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1738 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1739 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1740 uint8_t iocap_b[3]; 1741 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1742 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1743 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1744 if (IS_RESPONDER(sm_conn->sm_role)){ 1745 // responder 1746 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); 1747 } else { 1748 // initiator 1749 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); 1750 } 1751 } 1752 1753 1754 // 1755 // Link Key Conversion Function h6 1756 // 1757 // h6(W, keyID) = AES-CMACW(keyID) 1758 // - W is 128 bits 1759 // - keyID is 32 bits 1760 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1761 const uint16_t message_len = 4; 1762 sm_cmac_connection = sm_conn; 1763 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1764 log_info("h6 key"); 1765 log_info_hexdump(w, 16); 1766 log_info("h6 message"); 1767 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1768 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1769 } 1770 1771 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1772 // Errata Service Release to the Bluetooth Specification: ESR09 1773 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1774 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1775 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1776 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1777 } 1778 1779 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1780 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1781 } 1782 1783 #endif 1784 1785 // key management legacy connections: 1786 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1787 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1788 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1789 // - responder reconnects: responder uses LTK receveived from master 1790 1791 // key management secure connections: 1792 // - both devices store same LTK from ECDH key exchange. 1793 1794 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1795 static void sm_load_security_info(sm_connection_t * sm_connection){ 1796 int encryption_key_size; 1797 int authenticated; 1798 int authorized; 1799 1800 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1801 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1802 &encryption_key_size, &authenticated, &authorized); 1803 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1804 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1805 sm_connection->sm_connection_authenticated = authenticated; 1806 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1807 } 1808 #endif 1809 1810 #ifdef ENABLE_LE_PERIPHERAL 1811 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1812 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1813 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1814 // re-establish used key encryption size 1815 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1816 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1817 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1818 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1819 log_info("sm: received ltk request with key size %u, authenticated %u", 1820 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1821 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1822 } 1823 #endif 1824 1825 static void sm_run(void){ 1826 1827 btstack_linked_list_iterator_t it; 1828 1829 // assert that we can send at least commands 1830 if (!hci_can_send_command_packet_now()) return; 1831 1832 // 1833 // non-connection related behaviour 1834 // 1835 1836 // distributed key generation 1837 switch (dkg_state){ 1838 case DKG_CALC_IRK: 1839 // already busy? 1840 if (sm_aes128_state == SM_AES128_IDLE) { 1841 // IRK = d1(IR, 1, 0) 1842 sm_key_t d1_prime; 1843 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1844 dkg_next_state(); 1845 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1846 return; 1847 } 1848 break; 1849 case DKG_CALC_DHK: 1850 // already busy? 1851 if (sm_aes128_state == SM_AES128_IDLE) { 1852 // DHK = d1(IR, 3, 0) 1853 sm_key_t d1_prime; 1854 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1855 dkg_next_state(); 1856 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1857 return; 1858 } 1859 break; 1860 default: 1861 break; 1862 } 1863 1864 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1865 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1866 #ifdef USE_MBEDTLS_FOR_ECDH 1867 sm_random_start(NULL); 1868 #else 1869 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1870 hci_send_cmd(&hci_le_read_local_p256_public_key); 1871 #endif 1872 return; 1873 } 1874 #endif 1875 1876 // random address updates 1877 switch (rau_state){ 1878 case RAU_GET_RANDOM: 1879 rau_next_state(); 1880 sm_random_start(NULL); 1881 return; 1882 case RAU_GET_ENC: 1883 // already busy? 1884 if (sm_aes128_state == SM_AES128_IDLE) { 1885 sm_key_t r_prime; 1886 sm_ah_r_prime(sm_random_address, r_prime); 1887 rau_next_state(); 1888 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1889 return; 1890 } 1891 break; 1892 case RAU_SET_ADDRESS: 1893 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1894 rau_state = RAU_IDLE; 1895 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1896 return; 1897 default: 1898 break; 1899 } 1900 1901 #ifdef ENABLE_CMAC_ENGINE 1902 // CMAC 1903 switch (sm_cmac_state){ 1904 case CMAC_CALC_SUBKEYS: 1905 case CMAC_CALC_MI: 1906 case CMAC_CALC_MLAST: 1907 // already busy? 1908 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1909 sm_cmac_handle_aes_engine_ready(); 1910 return; 1911 default: 1912 break; 1913 } 1914 #endif 1915 1916 // CSRK Lookup 1917 // -- if csrk lookup ready, find connection that require csrk lookup 1918 if (sm_address_resolution_idle()){ 1919 hci_connections_get_iterator(&it); 1920 while(btstack_linked_list_iterator_has_next(&it)){ 1921 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1922 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1923 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1924 // and start lookup 1925 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); 1926 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1927 break; 1928 } 1929 } 1930 } 1931 1932 // -- if csrk lookup ready, resolved addresses for received addresses 1933 if (sm_address_resolution_idle()) { 1934 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1935 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1936 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1937 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1938 btstack_memory_sm_lookup_entry_free(entry); 1939 } 1940 } 1941 1942 // -- Continue with CSRK device lookup by public or resolvable private address 1943 if (!sm_address_resolution_idle()){ 1944 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1945 while (sm_address_resolution_test < le_device_db_count()){ 1946 int addr_type; 1947 bd_addr_t addr; 1948 sm_key_t irk; 1949 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1950 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1951 1952 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1953 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1954 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1955 break; 1956 } 1957 1958 if (sm_address_resolution_addr_type == 0){ 1959 sm_address_resolution_test++; 1960 continue; 1961 } 1962 1963 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1964 1965 log_info("LE Device Lookup: calculate AH"); 1966 log_info_key("IRK", irk); 1967 1968 sm_key_t r_prime; 1969 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1970 sm_address_resolution_ah_calculation_active = 1; 1971 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1972 return; 1973 } 1974 1975 if (sm_address_resolution_test >= le_device_db_count()){ 1976 log_info("LE Device Lookup: not found"); 1977 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1978 } 1979 } 1980 1981 // handle basic actions that don't requires the full context 1982 hci_connections_get_iterator(&it); 1983 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1984 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1985 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1986 switch(sm_connection->sm_engine_state){ 1987 // responder side 1988 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1989 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1990 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1991 return; 1992 1993 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1994 case SM_SC_RECEIVED_LTK_REQUEST: 1995 switch (sm_connection->sm_irk_lookup_state){ 1996 case IRK_LOOKUP_FAILED: 1997 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1998 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1999 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2000 return; 2001 default: 2002 break; 2003 } 2004 break; 2005 #endif 2006 default: 2007 break; 2008 } 2009 } 2010 2011 // 2012 // active connection handling 2013 // -- use loop to handle next connection if lock on setup context is released 2014 2015 while (1) { 2016 2017 // Find connections that requires setup context and make active if no other is locked 2018 hci_connections_get_iterator(&it); 2019 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 2020 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2021 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2022 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2023 int done = 1; 2024 int err; 2025 UNUSED(err); 2026 switch (sm_connection->sm_engine_state) { 2027 #ifdef ENABLE_LE_PERIPHERAL 2028 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2029 // send packet if possible, 2030 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2031 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2032 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2033 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2034 } else { 2035 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2036 } 2037 // don't lock sxetup context yet 2038 done = 0; 2039 break; 2040 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2041 sm_reset_setup(); 2042 sm_init_setup(sm_connection); 2043 // recover pairing request 2044 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2045 err = sm_stk_generation_init(sm_connection); 2046 if (err){ 2047 setup->sm_pairing_failed_reason = err; 2048 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2049 break; 2050 } 2051 sm_timeout_start(sm_connection); 2052 // generate random number first, if we need to show passkey 2053 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2054 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2055 break; 2056 } 2057 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2058 break; 2059 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2060 sm_reset_setup(); 2061 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2062 break; 2063 #endif 2064 #ifdef ENABLE_LE_CENTRAL 2065 case SM_INITIATOR_PH0_HAS_LTK: 2066 sm_reset_setup(); 2067 sm_load_security_info(sm_connection); 2068 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2069 break; 2070 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2071 sm_reset_setup(); 2072 sm_init_setup(sm_connection); 2073 sm_timeout_start(sm_connection); 2074 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2075 break; 2076 #endif 2077 2078 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2079 case SM_SC_RECEIVED_LTK_REQUEST: 2080 switch (sm_connection->sm_irk_lookup_state){ 2081 case IRK_LOOKUP_SUCCEEDED: 2082 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2083 // start using context by loading security info 2084 sm_reset_setup(); 2085 sm_load_security_info(sm_connection); 2086 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2087 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2088 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2089 break; 2090 } 2091 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2092 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2093 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2094 // don't lock setup context yet 2095 return; 2096 default: 2097 // just wait until IRK lookup is completed 2098 // don't lock setup context yet 2099 done = 0; 2100 break; 2101 } 2102 break; 2103 #endif 2104 default: 2105 done = 0; 2106 break; 2107 } 2108 if (done){ 2109 sm_active_connection = sm_connection->sm_handle; 2110 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2111 } 2112 } 2113 2114 // 2115 // active connection handling 2116 // 2117 2118 if (sm_active_connection == 0) return; 2119 2120 // assert that we could send a SM PDU - not needed for all of the following 2121 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2122 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2123 return; 2124 } 2125 2126 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2127 if (!connection) return; 2128 2129 // send keypress notifications 2130 if (setup->sm_keypress_notification != 0xff){ 2131 uint8_t buffer[2]; 2132 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2133 buffer[1] = setup->sm_keypress_notification; 2134 setup->sm_keypress_notification = 0xff; 2135 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2136 return; 2137 } 2138 2139 sm_key_t plaintext; 2140 int key_distribution_flags; 2141 UNUSED(key_distribution_flags); 2142 2143 log_info("sm_run: state %u", connection->sm_engine_state); 2144 2145 switch (connection->sm_engine_state){ 2146 2147 // general 2148 case SM_GENERAL_SEND_PAIRING_FAILED: { 2149 uint8_t buffer[2]; 2150 buffer[0] = SM_CODE_PAIRING_FAILED; 2151 buffer[1] = setup->sm_pairing_failed_reason; 2152 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2153 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2154 sm_done_for_handle(connection->sm_handle); 2155 break; 2156 } 2157 2158 // responding state 2159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2160 case SM_SC_W2_GET_RANDOM_A: 2161 sm_random_start(connection); 2162 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2163 break; 2164 case SM_SC_W2_GET_RANDOM_B: 2165 sm_random_start(connection); 2166 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2167 break; 2168 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2169 if (!sm_cmac_ready()) break; 2170 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2171 sm_sc_calculate_local_confirm(connection); 2172 break; 2173 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2174 if (!sm_cmac_ready()) break; 2175 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2176 sm_sc_calculate_remote_confirm(connection); 2177 break; 2178 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2179 if (!sm_cmac_ready()) break; 2180 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2181 sm_sc_calculate_f6_for_dhkey_check(connection); 2182 break; 2183 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2184 if (!sm_cmac_ready()) break; 2185 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2186 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2187 break; 2188 case SM_SC_W2_CALCULATE_F5_SALT: 2189 if (!sm_cmac_ready()) break; 2190 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2191 f5_calculate_salt(connection); 2192 break; 2193 case SM_SC_W2_CALCULATE_F5_MACKEY: 2194 if (!sm_cmac_ready()) break; 2195 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2196 f5_calculate_mackey(connection); 2197 break; 2198 case SM_SC_W2_CALCULATE_F5_LTK: 2199 if (!sm_cmac_ready()) break; 2200 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2201 f5_calculate_ltk(connection); 2202 break; 2203 case SM_SC_W2_CALCULATE_G2: 2204 if (!sm_cmac_ready()) break; 2205 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2206 g2_calculate(connection); 2207 break; 2208 case SM_SC_W2_CALCULATE_H6_ILK: 2209 if (!sm_cmac_ready()) break; 2210 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2211 h6_calculate_ilk(connection); 2212 break; 2213 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2214 if (!sm_cmac_ready()) break; 2215 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2216 h6_calculate_br_edr_link_key(connection); 2217 break; 2218 #endif 2219 2220 #ifdef ENABLE_LE_CENTRAL 2221 // initiator side 2222 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2223 sm_key_t peer_ltk_flipped; 2224 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2225 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2226 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2227 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2228 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2229 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2230 return; 2231 } 2232 2233 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2234 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2235 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2236 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2237 sm_timeout_reset(connection); 2238 break; 2239 #endif 2240 2241 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2242 2243 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2244 uint8_t buffer[65]; 2245 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2246 // 2247 reverse_256(ec_qx, &buffer[1]); 2248 reverse_256(ec_qy, &buffer[33]); 2249 2250 // stk generation method 2251 // passkey entry: notify app to show passkey or to request passkey 2252 switch (setup->sm_stk_generation_method){ 2253 case JUST_WORKS: 2254 case NK_BOTH_INPUT: 2255 if (IS_RESPONDER(connection->sm_role)){ 2256 // responder 2257 sm_sc_start_calculating_local_confirm(connection); 2258 } else { 2259 // initiator 2260 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2261 } 2262 break; 2263 case PK_INIT_INPUT: 2264 case PK_RESP_INPUT: 2265 case OK_BOTH_INPUT: 2266 // use random TK for display 2267 memcpy(setup->sm_ra, setup->sm_tk, 16); 2268 memcpy(setup->sm_rb, setup->sm_tk, 16); 2269 setup->sm_passkey_bit = 0; 2270 2271 if (IS_RESPONDER(connection->sm_role)){ 2272 // responder 2273 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2274 } else { 2275 // initiator 2276 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2277 } 2278 sm_trigger_user_response(connection); 2279 break; 2280 case OOB: 2281 // TODO: implement SC OOB 2282 break; 2283 } 2284 2285 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2286 sm_timeout_reset(connection); 2287 break; 2288 } 2289 case SM_SC_SEND_CONFIRMATION: { 2290 uint8_t buffer[17]; 2291 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2292 reverse_128(setup->sm_local_confirm, &buffer[1]); 2293 if (IS_RESPONDER(connection->sm_role)){ 2294 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2295 } else { 2296 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2297 } 2298 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2299 sm_timeout_reset(connection); 2300 break; 2301 } 2302 case SM_SC_SEND_PAIRING_RANDOM: { 2303 uint8_t buffer[17]; 2304 buffer[0] = SM_CODE_PAIRING_RANDOM; 2305 reverse_128(setup->sm_local_nonce, &buffer[1]); 2306 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2307 if (IS_RESPONDER(connection->sm_role)){ 2308 // responder 2309 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2310 } else { 2311 // initiator 2312 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2313 } 2314 } else { 2315 if (IS_RESPONDER(connection->sm_role)){ 2316 // responder 2317 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2318 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2319 } else { 2320 sm_sc_prepare_dhkey_check(connection); 2321 } 2322 } else { 2323 // initiator 2324 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2325 } 2326 } 2327 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2328 sm_timeout_reset(connection); 2329 break; 2330 } 2331 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2332 uint8_t buffer[17]; 2333 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2334 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2335 2336 if (IS_RESPONDER(connection->sm_role)){ 2337 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2338 } else { 2339 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2340 } 2341 2342 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2343 sm_timeout_reset(connection); 2344 break; 2345 } 2346 2347 #endif 2348 2349 #ifdef ENABLE_LE_PERIPHERAL 2350 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2351 // echo initiator for now 2352 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2353 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2354 2355 if (setup->sm_use_secure_connections){ 2356 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2357 // skip LTK/EDIV for SC 2358 log_info("sm: dropping encryption information flag"); 2359 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2360 } else { 2361 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2362 } 2363 2364 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); 2365 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); 2366 // update key distribution after ENC was dropped 2367 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2368 2369 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2370 sm_timeout_reset(connection); 2371 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2372 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2373 sm_trigger_user_response(connection); 2374 } 2375 return; 2376 #endif 2377 2378 case SM_PH2_SEND_PAIRING_RANDOM: { 2379 uint8_t buffer[17]; 2380 buffer[0] = SM_CODE_PAIRING_RANDOM; 2381 reverse_128(setup->sm_local_random, &buffer[1]); 2382 if (IS_RESPONDER(connection->sm_role)){ 2383 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2384 } else { 2385 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2386 } 2387 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2388 sm_timeout_reset(connection); 2389 break; 2390 } 2391 2392 case SM_PH2_GET_RANDOM_TK: 2393 case SM_PH2_C1_GET_RANDOM_A: 2394 case SM_PH2_C1_GET_RANDOM_B: 2395 case SM_PH3_GET_RANDOM: 2396 case SM_PH3_GET_DIV: 2397 sm_next_responding_state(connection); 2398 sm_random_start(connection); 2399 return; 2400 2401 case SM_PH2_C1_GET_ENC_B: 2402 case SM_PH2_C1_GET_ENC_D: 2403 // already busy? 2404 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2405 sm_next_responding_state(connection); 2406 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2407 return; 2408 2409 case SM_PH3_LTK_GET_ENC: 2410 case SM_RESPONDER_PH4_LTK_GET_ENC: 2411 // already busy? 2412 if (sm_aes128_state == SM_AES128_IDLE) { 2413 sm_key_t d_prime; 2414 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2415 sm_next_responding_state(connection); 2416 sm_aes128_start(sm_persistent_er, d_prime, connection); 2417 return; 2418 } 2419 break; 2420 2421 case SM_PH3_CSRK_GET_ENC: 2422 // already busy? 2423 if (sm_aes128_state == SM_AES128_IDLE) { 2424 sm_key_t d_prime; 2425 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2426 sm_next_responding_state(connection); 2427 sm_aes128_start(sm_persistent_er, d_prime, connection); 2428 return; 2429 } 2430 break; 2431 2432 case SM_PH2_C1_GET_ENC_C: 2433 // already busy? 2434 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2435 // calculate m_confirm using aes128 engine - step 1 2436 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); 2437 sm_next_responding_state(connection); 2438 sm_aes128_start(setup->sm_tk, plaintext, connection); 2439 break; 2440 case SM_PH2_C1_GET_ENC_A: 2441 // already busy? 2442 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2443 // calculate confirm using aes128 engine - step 1 2444 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); 2445 sm_next_responding_state(connection); 2446 sm_aes128_start(setup->sm_tk, plaintext, connection); 2447 break; 2448 case SM_PH2_CALC_STK: 2449 // already busy? 2450 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2451 // calculate STK 2452 if (IS_RESPONDER(connection->sm_role)){ 2453 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2454 } else { 2455 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2456 } 2457 sm_next_responding_state(connection); 2458 sm_aes128_start(setup->sm_tk, plaintext, connection); 2459 break; 2460 case SM_PH3_Y_GET_ENC: 2461 // already busy? 2462 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2463 // PH3B2 - calculate Y from - enc 2464 // Y = dm(DHK, Rand) 2465 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2466 sm_next_responding_state(connection); 2467 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2468 return; 2469 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2470 uint8_t buffer[17]; 2471 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2472 reverse_128(setup->sm_local_confirm, &buffer[1]); 2473 if (IS_RESPONDER(connection->sm_role)){ 2474 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2475 } else { 2476 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2477 } 2478 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2479 sm_timeout_reset(connection); 2480 return; 2481 } 2482 #ifdef ENABLE_LE_PERIPHERAL 2483 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2484 sm_key_t stk_flipped; 2485 reverse_128(setup->sm_ltk, stk_flipped); 2486 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2487 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2488 return; 2489 } 2490 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2491 sm_key_t ltk_flipped; 2492 reverse_128(setup->sm_ltk, ltk_flipped); 2493 connection->sm_engine_state = SM_RESPONDER_IDLE; 2494 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2495 return; 2496 } 2497 case SM_RESPONDER_PH4_Y_GET_ENC: 2498 // already busy? 2499 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2500 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2501 // Y = dm(DHK, Rand) 2502 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2503 sm_next_responding_state(connection); 2504 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2505 return; 2506 #endif 2507 #ifdef ENABLE_LE_CENTRAL 2508 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2509 sm_key_t stk_flipped; 2510 reverse_128(setup->sm_ltk, stk_flipped); 2511 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2512 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2513 return; 2514 } 2515 #endif 2516 2517 case SM_PH3_DISTRIBUTE_KEYS: 2518 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2519 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2520 uint8_t buffer[17]; 2521 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2522 reverse_128(setup->sm_ltk, &buffer[1]); 2523 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2524 sm_timeout_reset(connection); 2525 return; 2526 } 2527 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2528 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2529 uint8_t buffer[11]; 2530 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2531 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2532 reverse_64(setup->sm_local_rand, &buffer[3]); 2533 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2534 sm_timeout_reset(connection); 2535 return; 2536 } 2537 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2538 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2539 uint8_t buffer[17]; 2540 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2541 reverse_128(sm_persistent_irk, &buffer[1]); 2542 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2543 sm_timeout_reset(connection); 2544 return; 2545 } 2546 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2547 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2548 bd_addr_t local_address; 2549 uint8_t buffer[8]; 2550 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2551 gap_le_get_own_address(&buffer[1], local_address); 2552 reverse_bd_addr(local_address, &buffer[2]); 2553 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2554 sm_timeout_reset(connection); 2555 return; 2556 } 2557 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2558 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2559 2560 // hack to reproduce test runs 2561 if (test_use_fixed_local_csrk){ 2562 memset(setup->sm_local_csrk, 0xcc, 16); 2563 } 2564 2565 uint8_t buffer[17]; 2566 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2567 reverse_128(setup->sm_local_csrk, &buffer[1]); 2568 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2569 sm_timeout_reset(connection); 2570 return; 2571 } 2572 2573 // keys are sent 2574 if (IS_RESPONDER(connection->sm_role)){ 2575 // slave -> receive master keys if any 2576 if (sm_key_distribution_all_received(connection)){ 2577 sm_key_distribution_handle_all_received(connection); 2578 connection->sm_engine_state = SM_RESPONDER_IDLE; 2579 sm_done_for_handle(connection->sm_handle); 2580 } else { 2581 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2582 } 2583 } else { 2584 // master -> all done 2585 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2586 sm_done_for_handle(connection->sm_handle); 2587 } 2588 break; 2589 2590 default: 2591 break; 2592 } 2593 2594 // check again if active connection was released 2595 if (sm_active_connection) break; 2596 } 2597 } 2598 2599 // note: aes engine is ready as we just got the aes result 2600 static void sm_handle_encryption_result(uint8_t * data){ 2601 2602 sm_aes128_state = SM_AES128_IDLE; 2603 2604 if (sm_address_resolution_ah_calculation_active){ 2605 sm_address_resolution_ah_calculation_active = 0; 2606 // compare calulated address against connecting device 2607 uint8_t hash[3]; 2608 reverse_24(data, hash); 2609 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2610 log_info("LE Device Lookup: matched resolvable private address"); 2611 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2612 return; 2613 } 2614 // no match, try next 2615 sm_address_resolution_test++; 2616 return; 2617 } 2618 2619 switch (dkg_state){ 2620 case DKG_W4_IRK: 2621 reverse_128(data, sm_persistent_irk); 2622 log_info_key("irk", sm_persistent_irk); 2623 dkg_next_state(); 2624 return; 2625 case DKG_W4_DHK: 2626 reverse_128(data, sm_persistent_dhk); 2627 log_info_key("dhk", sm_persistent_dhk); 2628 dkg_next_state(); 2629 // SM Init Finished 2630 return; 2631 default: 2632 break; 2633 } 2634 2635 switch (rau_state){ 2636 case RAU_W4_ENC: 2637 reverse_24(data, &sm_random_address[3]); 2638 rau_next_state(); 2639 return; 2640 default: 2641 break; 2642 } 2643 2644 #ifdef ENABLE_CMAC_ENGINE 2645 switch (sm_cmac_state){ 2646 case CMAC_W4_SUBKEYS: 2647 case CMAC_W4_MI: 2648 case CMAC_W4_MLAST: 2649 { 2650 sm_key_t t; 2651 reverse_128(data, t); 2652 sm_cmac_handle_encryption_result(t); 2653 } 2654 return; 2655 default: 2656 break; 2657 } 2658 #endif 2659 2660 // retrieve sm_connection provided to sm_aes128_start_encryption 2661 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2662 if (!connection) return; 2663 switch (connection->sm_engine_state){ 2664 case SM_PH2_C1_W4_ENC_A: 2665 case SM_PH2_C1_W4_ENC_C: 2666 { 2667 sm_key_t t2; 2668 reverse_128(data, t2); 2669 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2670 } 2671 sm_next_responding_state(connection); 2672 return; 2673 case SM_PH2_C1_W4_ENC_B: 2674 reverse_128(data, setup->sm_local_confirm); 2675 log_info_key("c1!", setup->sm_local_confirm); 2676 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2677 return; 2678 case SM_PH2_C1_W4_ENC_D: 2679 { 2680 sm_key_t peer_confirm_test; 2681 reverse_128(data, peer_confirm_test); 2682 log_info_key("c1!", peer_confirm_test); 2683 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2684 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2685 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2686 return; 2687 } 2688 if (IS_RESPONDER(connection->sm_role)){ 2689 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2690 } else { 2691 connection->sm_engine_state = SM_PH2_CALC_STK; 2692 } 2693 } 2694 return; 2695 case SM_PH2_W4_STK: 2696 reverse_128(data, setup->sm_ltk); 2697 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2698 log_info_key("stk", setup->sm_ltk); 2699 if (IS_RESPONDER(connection->sm_role)){ 2700 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2701 } else { 2702 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2703 } 2704 return; 2705 case SM_PH3_Y_W4_ENC:{ 2706 sm_key_t y128; 2707 reverse_128(data, y128); 2708 setup->sm_local_y = big_endian_read_16(y128, 14); 2709 log_info_hex16("y", setup->sm_local_y); 2710 // PH3B3 - calculate EDIV 2711 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2712 log_info_hex16("ediv", setup->sm_local_ediv); 2713 // PH3B4 - calculate LTK - enc 2714 // LTK = d1(ER, DIV, 0)) 2715 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2716 return; 2717 } 2718 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2719 sm_key_t y128; 2720 reverse_128(data, y128); 2721 setup->sm_local_y = big_endian_read_16(y128, 14); 2722 log_info_hex16("y", setup->sm_local_y); 2723 2724 // PH3B3 - calculate DIV 2725 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2726 log_info_hex16("ediv", setup->sm_local_ediv); 2727 // PH3B4 - calculate LTK - enc 2728 // LTK = d1(ER, DIV, 0)) 2729 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2730 return; 2731 } 2732 case SM_PH3_LTK_W4_ENC: 2733 reverse_128(data, setup->sm_ltk); 2734 log_info_key("ltk", setup->sm_ltk); 2735 // calc CSRK next 2736 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2737 return; 2738 case SM_PH3_CSRK_W4_ENC: 2739 reverse_128(data, setup->sm_local_csrk); 2740 log_info_key("csrk", setup->sm_local_csrk); 2741 if (setup->sm_key_distribution_send_set){ 2742 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2743 } else { 2744 // no keys to send, just continue 2745 if (IS_RESPONDER(connection->sm_role)){ 2746 // slave -> receive master keys 2747 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2748 } else { 2749 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2750 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2751 } else { 2752 // master -> all done 2753 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2754 sm_done_for_handle(connection->sm_handle); 2755 } 2756 } 2757 } 2758 return; 2759 #ifdef ENABLE_LE_PERIPHERAL 2760 case SM_RESPONDER_PH4_LTK_W4_ENC: 2761 reverse_128(data, setup->sm_ltk); 2762 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2763 log_info_key("ltk", setup->sm_ltk); 2764 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2765 return; 2766 #endif 2767 default: 2768 break; 2769 } 2770 } 2771 2772 #ifdef USE_MBEDTLS_FOR_ECDH 2773 2774 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2775 UNUSED(context); 2776 2777 int offset = setup->sm_passkey_bit; 2778 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2779 while (size) { 2780 if (offset < 32){ 2781 *buffer++ = setup->sm_peer_qx[offset++]; 2782 } else { 2783 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2784 } 2785 size--; 2786 } 2787 setup->sm_passkey_bit = offset; 2788 return 0; 2789 } 2790 #endif 2791 2792 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2793 static void sm_handle_random_result(uint8_t * data){ 2794 2795 #ifdef USE_MBEDTLS_FOR_ECDH 2796 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2797 int num_bytes = setup->sm_passkey_bit; 2798 if (num_bytes < 32){ 2799 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2800 } else { 2801 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2802 } 2803 num_bytes += 8; 2804 setup->sm_passkey_bit = num_bytes; 2805 2806 if (num_bytes >= 64){ 2807 2808 // generate EC key 2809 setup->sm_passkey_bit = 0; 2810 mbedtls_mpi d; 2811 mbedtls_ecp_point P; 2812 mbedtls_mpi_init(&d); 2813 mbedtls_ecp_point_init(&P); 2814 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2815 log_info("gen keypair %x", res); 2816 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2817 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2818 mbedtls_mpi_write_binary(&d, ec_d, 32); 2819 mbedtls_ecp_point_free(&P); 2820 mbedtls_mpi_free(&d); 2821 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2822 log_info("Elliptic curve: d"); 2823 log_info_hexdump(ec_d,32); 2824 sm_log_ec_keypair(); 2825 2826 #if 0 2827 int i; 2828 sm_key256_t dhkey; 2829 for (i=0;i<10;i++){ 2830 // printf("test dhkey check\n"); 2831 memcpy(setup->sm_peer_qx, ec_qx, 32); 2832 memcpy(setup->sm_peer_qy, ec_qy, 32); 2833 sm_sc_calculate_dhkey(dhkey); 2834 // printf("test dhkey check end\n"); 2835 } 2836 #endif 2837 2838 } 2839 } 2840 #endif 2841 2842 switch (rau_state){ 2843 case RAU_W4_RANDOM: 2844 // non-resolvable vs. resolvable 2845 switch (gap_random_adress_type){ 2846 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2847 // resolvable: use random as prand and calc address hash 2848 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2849 memcpy(sm_random_address, data, 3); 2850 sm_random_address[0] &= 0x3f; 2851 sm_random_address[0] |= 0x40; 2852 rau_state = RAU_GET_ENC; 2853 break; 2854 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2855 default: 2856 // "The two most significant bits of the address shall be equal to ‘0’"" 2857 memcpy(sm_random_address, data, 6); 2858 sm_random_address[0] &= 0x3f; 2859 rau_state = RAU_SET_ADDRESS; 2860 break; 2861 } 2862 return; 2863 default: 2864 break; 2865 } 2866 2867 // retrieve sm_connection provided to sm_random_start 2868 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2869 if (!connection) return; 2870 switch (connection->sm_engine_state){ 2871 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2872 case SM_SC_W4_GET_RANDOM_A: 2873 memcpy(&setup->sm_local_nonce[0], data, 8); 2874 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2875 break; 2876 case SM_SC_W4_GET_RANDOM_B: 2877 memcpy(&setup->sm_local_nonce[8], data, 8); 2878 // initiator & jw/nc -> send pairing random 2879 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2880 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2881 break; 2882 } else { 2883 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2884 } 2885 break; 2886 #endif 2887 2888 case SM_PH2_W4_RANDOM_TK: 2889 { 2890 // map random to 0-999999 without speding much cycles on a modulus operation 2891 uint32_t tk = little_endian_read_32(data,0); 2892 tk = tk & 0xfffff; // 1048575 2893 if (tk >= 999999){ 2894 tk = tk - 999999; 2895 } 2896 sm_reset_tk(); 2897 big_endian_store_32(setup->sm_tk, 12, tk); 2898 if (IS_RESPONDER(connection->sm_role)){ 2899 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2900 } else { 2901 if (setup->sm_use_secure_connections){ 2902 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2903 } else { 2904 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2905 sm_trigger_user_response(connection); 2906 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2907 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2908 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2909 } 2910 } 2911 } 2912 return; 2913 } 2914 case SM_PH2_C1_W4_RANDOM_A: 2915 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2916 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2917 return; 2918 case SM_PH2_C1_W4_RANDOM_B: 2919 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2920 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2921 return; 2922 case SM_PH3_W4_RANDOM: 2923 reverse_64(data, setup->sm_local_rand); 2924 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2925 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2926 // no db for authenticated flag hack: store flag in bit 4 of LSB 2927 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2928 connection->sm_engine_state = SM_PH3_GET_DIV; 2929 return; 2930 case SM_PH3_W4_DIV: 2931 // use 16 bit from random value as div 2932 setup->sm_local_div = big_endian_read_16(data, 0); 2933 log_info_hex16("div", setup->sm_local_div); 2934 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2935 return; 2936 default: 2937 break; 2938 } 2939 } 2940 2941 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2942 2943 UNUSED(channel); 2944 UNUSED(size); 2945 2946 sm_connection_t * sm_conn; 2947 hci_con_handle_t con_handle; 2948 2949 switch (packet_type) { 2950 2951 case HCI_EVENT_PACKET: 2952 switch (hci_event_packet_get_type(packet)) { 2953 2954 case BTSTACK_EVENT_STATE: 2955 // bt stack activated, get started 2956 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2957 log_info("HCI Working!"); 2958 2959 // set local addr for le device db 2960 bd_addr_t local_bd_addr; 2961 gap_local_bd_addr(local_bd_addr); 2962 le_device_db_set_local_bd_addr(local_bd_addr); 2963 2964 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2965 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2966 if (!sm_have_ec_keypair){ 2967 setup->sm_passkey_bit = 0; 2968 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2969 } 2970 #endif 2971 // trigger Random Address generation if requested before 2972 switch (gap_random_adress_type){ 2973 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2974 rau_state = RAU_IDLE; 2975 break; 2976 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2977 rau_state = RAU_SET_ADDRESS; 2978 break; 2979 default: 2980 rau_state = RAU_GET_RANDOM; 2981 break; 2982 } 2983 sm_run(); 2984 } 2985 break; 2986 2987 case HCI_EVENT_LE_META: 2988 switch (packet[2]) { 2989 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2990 2991 log_info("sm: connected"); 2992 2993 if (packet[3]) return; // connection failed 2994 2995 con_handle = little_endian_read_16(packet, 4); 2996 sm_conn = sm_get_connection_for_handle(con_handle); 2997 if (!sm_conn) break; 2998 2999 sm_conn->sm_handle = con_handle; 3000 sm_conn->sm_role = packet[6]; 3001 sm_conn->sm_peer_addr_type = packet[7]; 3002 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3003 3004 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3005 3006 // reset security properties 3007 sm_conn->sm_connection_encrypted = 0; 3008 sm_conn->sm_connection_authenticated = 0; 3009 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3010 sm_conn->sm_le_db_index = -1; 3011 3012 // prepare CSRK lookup (does not involve setup) 3013 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3014 3015 // just connected -> everything else happens in sm_run() 3016 if (IS_RESPONDER(sm_conn->sm_role)){ 3017 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3018 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3019 if (sm_slave_request_security) { 3020 // request security if requested by app 3021 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3022 } else { 3023 // otherwise, wait for pairing request 3024 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3025 } 3026 } 3027 break; 3028 } else { 3029 // master 3030 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3031 } 3032 break; 3033 3034 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3035 con_handle = little_endian_read_16(packet, 3); 3036 sm_conn = sm_get_connection_for_handle(con_handle); 3037 if (!sm_conn) break; 3038 3039 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3040 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3041 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3042 break; 3043 } 3044 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3045 // PH2 SEND LTK as we need to exchange keys in PH3 3046 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3047 break; 3048 } 3049 3050 // store rand and ediv 3051 reverse_64(&packet[5], sm_conn->sm_local_rand); 3052 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3053 3054 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3055 // potentially stored LTK is from the master 3056 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3057 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3058 break; 3059 } 3060 3061 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3062 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3063 #else 3064 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3065 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3066 #endif 3067 break; 3068 3069 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3070 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3071 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3072 log_error("Read Local P256 Public Key failed"); 3073 break; 3074 } 3075 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, ec_qx); 3076 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, ec_qy); 3077 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3078 sm_log_ec_keypair(); 3079 break; 3080 #endif 3081 default: 3082 break; 3083 } 3084 break; 3085 3086 case HCI_EVENT_ENCRYPTION_CHANGE: 3087 con_handle = little_endian_read_16(packet, 3); 3088 sm_conn = sm_get_connection_for_handle(con_handle); 3089 if (!sm_conn) break; 3090 3091 sm_conn->sm_connection_encrypted = packet[5]; 3092 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3093 sm_conn->sm_actual_encryption_key_size); 3094 log_info("event handler, state %u", sm_conn->sm_engine_state); 3095 if (!sm_conn->sm_connection_encrypted) break; 3096 // continue if part of initial pairing 3097 switch (sm_conn->sm_engine_state){ 3098 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3099 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3100 sm_done_for_handle(sm_conn->sm_handle); 3101 break; 3102 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3103 if (IS_RESPONDER(sm_conn->sm_role)){ 3104 // slave 3105 if (setup->sm_use_secure_connections){ 3106 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3107 } else { 3108 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3109 } 3110 } else { 3111 // master 3112 if (sm_key_distribution_all_received(sm_conn)){ 3113 // skip receiving keys as there are none 3114 sm_key_distribution_handle_all_received(sm_conn); 3115 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3116 } else { 3117 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3118 } 3119 } 3120 break; 3121 default: 3122 break; 3123 } 3124 break; 3125 3126 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3127 con_handle = little_endian_read_16(packet, 3); 3128 sm_conn = sm_get_connection_for_handle(con_handle); 3129 if (!sm_conn) break; 3130 3131 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3132 log_info("event handler, state %u", sm_conn->sm_engine_state); 3133 // continue if part of initial pairing 3134 switch (sm_conn->sm_engine_state){ 3135 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3136 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3137 sm_done_for_handle(sm_conn->sm_handle); 3138 break; 3139 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3140 if (IS_RESPONDER(sm_conn->sm_role)){ 3141 // slave 3142 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3143 } else { 3144 // master 3145 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3146 } 3147 break; 3148 default: 3149 break; 3150 } 3151 break; 3152 3153 3154 case HCI_EVENT_DISCONNECTION_COMPLETE: 3155 con_handle = little_endian_read_16(packet, 3); 3156 sm_done_for_handle(con_handle); 3157 sm_conn = sm_get_connection_for_handle(con_handle); 3158 if (!sm_conn) break; 3159 3160 // delete stored bonding on disconnect with authentication failure in ph0 3161 if (sm_conn->sm_role == 0 3162 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3163 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3164 le_device_db_remove(sm_conn->sm_le_db_index); 3165 } 3166 3167 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3168 sm_conn->sm_handle = 0; 3169 break; 3170 3171 case HCI_EVENT_COMMAND_COMPLETE: 3172 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3173 sm_handle_encryption_result(&packet[6]); 3174 break; 3175 } 3176 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3177 sm_handle_random_result(&packet[6]); 3178 break; 3179 } 3180 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3181 // Hack for Nordic nRF5 series that doesn't have public address: 3182 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3183 // - we use this as default for advertisements/connections 3184 if (hci_get_manufacturer() == BLUETOOTH_COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3185 log_info("nRF5: using (fake) public address as random static address"); 3186 bd_addr_t addr; 3187 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3188 gap_random_address_set(addr); 3189 } 3190 } 3191 break; 3192 default: 3193 break; 3194 } 3195 break; 3196 default: 3197 break; 3198 } 3199 3200 sm_run(); 3201 } 3202 3203 static inline int sm_calc_actual_encryption_key_size(int other){ 3204 if (other < sm_min_encryption_key_size) return 0; 3205 if (other < sm_max_encryption_key_size) return other; 3206 return sm_max_encryption_key_size; 3207 } 3208 3209 3210 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3211 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3212 switch (method){ 3213 case JUST_WORKS: 3214 case NK_BOTH_INPUT: 3215 return 1; 3216 default: 3217 return 0; 3218 } 3219 } 3220 // responder 3221 3222 static int sm_passkey_used(stk_generation_method_t method){ 3223 switch (method){ 3224 case PK_RESP_INPUT: 3225 return 1; 3226 default: 3227 return 0; 3228 } 3229 } 3230 #endif 3231 3232 /** 3233 * @return ok 3234 */ 3235 static int sm_validate_stk_generation_method(void){ 3236 // check if STK generation method is acceptable by client 3237 switch (setup->sm_stk_generation_method){ 3238 case JUST_WORKS: 3239 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3240 case PK_RESP_INPUT: 3241 case PK_INIT_INPUT: 3242 case OK_BOTH_INPUT: 3243 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3244 case OOB: 3245 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3246 case NK_BOTH_INPUT: 3247 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3248 return 1; 3249 default: 3250 return 0; 3251 } 3252 } 3253 3254 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3255 3256 UNUSED(size); 3257 3258 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3259 sm_run(); 3260 } 3261 3262 if (packet_type != SM_DATA_PACKET) return; 3263 3264 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3265 if (!sm_conn) return; 3266 3267 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3268 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3269 return; 3270 } 3271 3272 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3273 3274 int err; 3275 UNUSED(err); 3276 3277 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3278 uint8_t buffer[5]; 3279 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3280 buffer[1] = 3; 3281 little_endian_store_16(buffer, 2, con_handle); 3282 buffer[4] = packet[1]; 3283 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3284 return; 3285 } 3286 3287 switch (sm_conn->sm_engine_state){ 3288 3289 // a sm timeout requries a new physical connection 3290 case SM_GENERAL_TIMEOUT: 3291 return; 3292 3293 #ifdef ENABLE_LE_CENTRAL 3294 3295 // Initiator 3296 case SM_INITIATOR_CONNECTED: 3297 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3298 sm_pdu_received_in_wrong_state(sm_conn); 3299 break; 3300 } 3301 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3302 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3303 break; 3304 } 3305 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3306 sm_key_t ltk; 3307 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3308 if (!sm_is_null_key(ltk)){ 3309 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3310 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3311 } else { 3312 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3313 } 3314 break; 3315 } 3316 // otherwise, store security request 3317 sm_conn->sm_security_request_received = 1; 3318 break; 3319 3320 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3321 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3322 sm_pdu_received_in_wrong_state(sm_conn); 3323 break; 3324 } 3325 // store pairing request 3326 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3327 err = sm_stk_generation_init(sm_conn); 3328 if (err){ 3329 setup->sm_pairing_failed_reason = err; 3330 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3331 break; 3332 } 3333 3334 // generate random number first, if we need to show passkey 3335 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3336 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3337 break; 3338 } 3339 3340 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3341 if (setup->sm_use_secure_connections){ 3342 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3343 if (setup->sm_stk_generation_method == JUST_WORKS){ 3344 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3345 sm_trigger_user_response(sm_conn); 3346 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3347 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3348 } 3349 } else { 3350 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3351 } 3352 break; 3353 } 3354 #endif 3355 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3356 sm_trigger_user_response(sm_conn); 3357 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3358 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3359 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3360 } 3361 break; 3362 3363 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3364 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3365 sm_pdu_received_in_wrong_state(sm_conn); 3366 break; 3367 } 3368 3369 // store s_confirm 3370 reverse_128(&packet[1], setup->sm_peer_confirm); 3371 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3372 break; 3373 3374 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3375 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3376 sm_pdu_received_in_wrong_state(sm_conn); 3377 break;; 3378 } 3379 3380 // received random value 3381 reverse_128(&packet[1], setup->sm_peer_random); 3382 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3383 break; 3384 #endif 3385 3386 #ifdef ENABLE_LE_PERIPHERAL 3387 // Responder 3388 case SM_RESPONDER_IDLE: 3389 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3390 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3391 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3392 sm_pdu_received_in_wrong_state(sm_conn); 3393 break;; 3394 } 3395 3396 // store pairing request 3397 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3398 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3399 break; 3400 #endif 3401 3402 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3403 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3404 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3405 sm_pdu_received_in_wrong_state(sm_conn); 3406 break; 3407 } 3408 3409 // store public key for DH Key calculation 3410 reverse_256(&packet[01], setup->sm_peer_qx); 3411 reverse_256(&packet[33], setup->sm_peer_qy); 3412 3413 #ifdef USE_MBEDTLS_FOR_ECDH 3414 // validate public key 3415 mbedtls_ecp_point Q; 3416 mbedtls_ecp_point_init( &Q ); 3417 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3418 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3419 mbedtls_mpi_lset(&Q.Z, 1); 3420 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3421 mbedtls_ecp_point_free( & Q); 3422 if (err){ 3423 log_error("sm: peer public key invalid %x", err); 3424 // uses "unspecified reason", there is no "public key invalid" error code 3425 sm_pdu_received_in_wrong_state(sm_conn); 3426 break; 3427 } 3428 3429 #endif 3430 if (IS_RESPONDER(sm_conn->sm_role)){ 3431 // responder 3432 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3433 } else { 3434 // initiator 3435 // stk generation method 3436 // passkey entry: notify app to show passkey or to request passkey 3437 switch (setup->sm_stk_generation_method){ 3438 case JUST_WORKS: 3439 case NK_BOTH_INPUT: 3440 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3441 break; 3442 case PK_RESP_INPUT: 3443 sm_sc_start_calculating_local_confirm(sm_conn); 3444 break; 3445 case PK_INIT_INPUT: 3446 case OK_BOTH_INPUT: 3447 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3448 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3449 break; 3450 } 3451 sm_sc_start_calculating_local_confirm(sm_conn); 3452 break; 3453 case OOB: 3454 // TODO: implement SC OOB 3455 break; 3456 } 3457 } 3458 break; 3459 3460 case SM_SC_W4_CONFIRMATION: 3461 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3462 sm_pdu_received_in_wrong_state(sm_conn); 3463 break; 3464 } 3465 // received confirm value 3466 reverse_128(&packet[1], setup->sm_peer_confirm); 3467 3468 if (IS_RESPONDER(sm_conn->sm_role)){ 3469 // responder 3470 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3471 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3472 // still waiting for passkey 3473 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3474 break; 3475 } 3476 } 3477 sm_sc_start_calculating_local_confirm(sm_conn); 3478 } else { 3479 // initiator 3480 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3481 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3482 } else { 3483 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3484 } 3485 } 3486 break; 3487 3488 case SM_SC_W4_PAIRING_RANDOM: 3489 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3490 sm_pdu_received_in_wrong_state(sm_conn); 3491 break; 3492 } 3493 3494 // received random value 3495 reverse_128(&packet[1], setup->sm_peer_nonce); 3496 3497 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3498 // only check for JUST WORK/NC in initiator role AND passkey entry 3499 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3500 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3501 } 3502 3503 sm_sc_state_after_receiving_random(sm_conn); 3504 break; 3505 3506 case SM_SC_W2_CALCULATE_G2: 3507 case SM_SC_W4_CALCULATE_G2: 3508 case SM_SC_W2_CALCULATE_F5_SALT: 3509 case SM_SC_W4_CALCULATE_F5_SALT: 3510 case SM_SC_W2_CALCULATE_F5_MACKEY: 3511 case SM_SC_W4_CALCULATE_F5_MACKEY: 3512 case SM_SC_W2_CALCULATE_F5_LTK: 3513 case SM_SC_W4_CALCULATE_F5_LTK: 3514 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3515 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3516 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3517 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3518 sm_pdu_received_in_wrong_state(sm_conn); 3519 break; 3520 } 3521 // store DHKey Check 3522 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3523 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3524 3525 // have we been only waiting for dhkey check command? 3526 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3527 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3528 } 3529 break; 3530 #endif 3531 3532 #ifdef ENABLE_LE_PERIPHERAL 3533 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3534 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3535 sm_pdu_received_in_wrong_state(sm_conn); 3536 break; 3537 } 3538 3539 // received confirm value 3540 reverse_128(&packet[1], setup->sm_peer_confirm); 3541 3542 // notify client to hide shown passkey 3543 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3544 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3545 } 3546 3547 // handle user cancel pairing? 3548 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3549 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3550 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3551 break; 3552 } 3553 3554 // wait for user action? 3555 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3556 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3557 break; 3558 } 3559 3560 // calculate and send local_confirm 3561 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3562 break; 3563 3564 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3565 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3566 sm_pdu_received_in_wrong_state(sm_conn); 3567 break;; 3568 } 3569 3570 // received random value 3571 reverse_128(&packet[1], setup->sm_peer_random); 3572 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3573 break; 3574 #endif 3575 3576 case SM_PH3_RECEIVE_KEYS: 3577 switch(packet[0]){ 3578 case SM_CODE_ENCRYPTION_INFORMATION: 3579 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3580 reverse_128(&packet[1], setup->sm_peer_ltk); 3581 break; 3582 3583 case SM_CODE_MASTER_IDENTIFICATION: 3584 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3585 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3586 reverse_64(&packet[3], setup->sm_peer_rand); 3587 break; 3588 3589 case SM_CODE_IDENTITY_INFORMATION: 3590 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3591 reverse_128(&packet[1], setup->sm_peer_irk); 3592 break; 3593 3594 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3595 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3596 setup->sm_peer_addr_type = packet[1]; 3597 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3598 break; 3599 3600 case SM_CODE_SIGNING_INFORMATION: 3601 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3602 reverse_128(&packet[1], setup->sm_peer_csrk); 3603 break; 3604 default: 3605 // Unexpected PDU 3606 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3607 break; 3608 } 3609 // done with key distribution? 3610 if (sm_key_distribution_all_received(sm_conn)){ 3611 3612 sm_key_distribution_handle_all_received(sm_conn); 3613 3614 if (IS_RESPONDER(sm_conn->sm_role)){ 3615 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3616 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3617 } else { 3618 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3619 sm_done_for_handle(sm_conn->sm_handle); 3620 } 3621 } else { 3622 if (setup->sm_use_secure_connections){ 3623 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3624 } else { 3625 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3626 } 3627 } 3628 } 3629 break; 3630 default: 3631 // Unexpected PDU 3632 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3633 break; 3634 } 3635 3636 // try to send preparared packet 3637 sm_run(); 3638 } 3639 3640 // Security Manager Client API 3641 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3642 sm_get_oob_data = get_oob_data_callback; 3643 } 3644 3645 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3646 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3647 } 3648 3649 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3650 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3651 } 3652 3653 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3654 sm_min_encryption_key_size = min_size; 3655 sm_max_encryption_key_size = max_size; 3656 } 3657 3658 void sm_set_authentication_requirements(uint8_t auth_req){ 3659 sm_auth_req = auth_req; 3660 } 3661 3662 void sm_set_io_capabilities(io_capability_t io_capability){ 3663 sm_io_capabilities = io_capability; 3664 } 3665 3666 #ifdef ENABLE_LE_PERIPHERAL 3667 void sm_set_request_security(int enable){ 3668 sm_slave_request_security = enable; 3669 } 3670 #endif 3671 3672 void sm_set_er(sm_key_t er){ 3673 memcpy(sm_persistent_er, er, 16); 3674 } 3675 3676 void sm_set_ir(sm_key_t ir){ 3677 memcpy(sm_persistent_ir, ir, 16); 3678 } 3679 3680 // Testing support only 3681 void sm_test_set_irk(sm_key_t irk){ 3682 memcpy(sm_persistent_irk, irk, 16); 3683 sm_persistent_irk_ready = 1; 3684 } 3685 3686 void sm_test_use_fixed_local_csrk(void){ 3687 test_use_fixed_local_csrk = 1; 3688 } 3689 3690 void sm_init(void){ 3691 // set some (BTstack default) ER and IR 3692 int i; 3693 sm_key_t er; 3694 sm_key_t ir; 3695 for (i=0;i<16;i++){ 3696 er[i] = 0x30 + i; 3697 ir[i] = 0x90 + i; 3698 } 3699 sm_set_er(er); 3700 sm_set_ir(ir); 3701 // defaults 3702 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3703 | SM_STK_GENERATION_METHOD_OOB 3704 | SM_STK_GENERATION_METHOD_PASSKEY 3705 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3706 3707 sm_max_encryption_key_size = 16; 3708 sm_min_encryption_key_size = 7; 3709 3710 #ifdef ENABLE_CMAC_ENGINE 3711 sm_cmac_state = CMAC_IDLE; 3712 #endif 3713 dkg_state = DKG_W4_WORKING; 3714 rau_state = RAU_W4_WORKING; 3715 sm_aes128_state = SM_AES128_IDLE; 3716 sm_address_resolution_test = -1; // no private address to resolve yet 3717 sm_address_resolution_ah_calculation_active = 0; 3718 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3719 sm_address_resolution_general_queue = NULL; 3720 3721 gap_random_adress_update_period = 15 * 60 * 1000L; 3722 sm_active_connection = 0; 3723 3724 test_use_fixed_local_csrk = 0; 3725 3726 // register for HCI Events from HCI 3727 hci_event_callback_registration.callback = &sm_event_packet_handler; 3728 hci_add_event_handler(&hci_event_callback_registration); 3729 3730 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3731 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3732 3733 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3734 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3735 #endif 3736 3737 #ifdef USE_MBEDTLS_FOR_ECDH 3738 3739 #ifndef HAVE_MALLOC 3740 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3741 #endif 3742 mbedtls_ecp_group_init(&mbedtls_ec_group); 3743 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3744 #if 0 3745 // test 3746 sm_test_use_fixed_ec_keypair(); 3747 if (sm_have_ec_keypair){ 3748 printf("test dhkey check\n"); 3749 sm_key256_t dhkey; 3750 memcpy(setup->sm_peer_qx, ec_qx, 32); 3751 memcpy(setup->sm_peer_qy, ec_qy, 32); 3752 sm_sc_calculate_dhkey(dhkey); 3753 } 3754 #endif 3755 #endif 3756 } 3757 3758 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3759 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3760 memcpy(ec_qx, qx, 32); 3761 memcpy(ec_qy, qy, 32); 3762 memcpy(ec_d, d, 32); 3763 sm_have_ec_keypair = 1; 3764 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3765 #else 3766 UNUSED(qx); 3767 UNUSED(qy); 3768 UNUSED(d); 3769 #endif 3770 } 3771 3772 void sm_test_use_fixed_ec_keypair(void){ 3773 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3774 #ifdef USE_MBEDTLS_FOR_ECDH 3775 // use test keypair from spec 3776 mbedtls_mpi x; 3777 mbedtls_mpi_init(&x); 3778 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3779 mbedtls_mpi_write_binary(&x, ec_d, 32); 3780 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3781 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3782 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3783 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3784 mbedtls_mpi_free(&x); 3785 #endif 3786 sm_have_ec_keypair = 1; 3787 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3788 #endif 3789 } 3790 3791 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3792 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3793 if (!hci_con) return NULL; 3794 return &hci_con->sm_connection; 3795 } 3796 3797 // @returns 0 if not encrypted, 7-16 otherwise 3798 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3799 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3800 if (!sm_conn) return 0; // wrong connection 3801 if (!sm_conn->sm_connection_encrypted) return 0; 3802 return sm_conn->sm_actual_encryption_key_size; 3803 } 3804 3805 int sm_authenticated(hci_con_handle_t con_handle){ 3806 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3807 if (!sm_conn) return 0; // wrong connection 3808 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3809 return sm_conn->sm_connection_authenticated; 3810 } 3811 3812 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3813 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3814 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3815 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3816 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3817 return sm_conn->sm_connection_authorization_state; 3818 } 3819 3820 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3821 switch (sm_conn->sm_engine_state){ 3822 case SM_GENERAL_IDLE: 3823 case SM_RESPONDER_IDLE: 3824 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3825 sm_run(); 3826 break; 3827 default: 3828 break; 3829 } 3830 } 3831 3832 /** 3833 * @brief Trigger Security Request 3834 */ 3835 void sm_send_security_request(hci_con_handle_t con_handle){ 3836 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3837 if (!sm_conn) return; 3838 sm_send_security_request_for_connection(sm_conn); 3839 } 3840 3841 // request pairing 3842 void sm_request_pairing(hci_con_handle_t con_handle){ 3843 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3844 if (!sm_conn) return; // wrong connection 3845 3846 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3847 if (IS_RESPONDER(sm_conn->sm_role)){ 3848 sm_send_security_request_for_connection(sm_conn); 3849 } else { 3850 // used as a trigger to start central/master/initiator security procedures 3851 uint16_t ediv; 3852 sm_key_t ltk; 3853 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3854 switch (sm_conn->sm_irk_lookup_state){ 3855 case IRK_LOOKUP_FAILED: 3856 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3857 break; 3858 case IRK_LOOKUP_SUCCEEDED: 3859 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3860 if (!sm_is_null_key(ltk) || ediv){ 3861 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3862 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3863 } else { 3864 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3865 } 3866 break; 3867 default: 3868 sm_conn->sm_bonding_requested = 1; 3869 break; 3870 } 3871 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3872 sm_conn->sm_bonding_requested = 1; 3873 } 3874 } 3875 sm_run(); 3876 } 3877 3878 // called by client app on authorization request 3879 void sm_authorization_decline(hci_con_handle_t con_handle){ 3880 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3881 if (!sm_conn) return; // wrong connection 3882 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3883 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3884 } 3885 3886 void sm_authorization_grant(hci_con_handle_t con_handle){ 3887 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3888 if (!sm_conn) return; // wrong connection 3889 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3890 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3891 } 3892 3893 // GAP Bonding API 3894 3895 void sm_bonding_decline(hci_con_handle_t con_handle){ 3896 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3897 if (!sm_conn) return; // wrong connection 3898 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3899 3900 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3901 switch (setup->sm_stk_generation_method){ 3902 case PK_RESP_INPUT: 3903 case PK_INIT_INPUT: 3904 case OK_BOTH_INPUT: 3905 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3906 break; 3907 case NK_BOTH_INPUT: 3908 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3909 break; 3910 case JUST_WORKS: 3911 case OOB: 3912 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3913 break; 3914 } 3915 } 3916 sm_run(); 3917 } 3918 3919 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3920 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3921 if (!sm_conn) return; // wrong connection 3922 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3923 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3924 if (setup->sm_use_secure_connections){ 3925 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3926 } else { 3927 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3928 } 3929 } 3930 3931 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3932 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3933 sm_sc_prepare_dhkey_check(sm_conn); 3934 } 3935 #endif 3936 3937 sm_run(); 3938 } 3939 3940 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3941 // for now, it's the same 3942 sm_just_works_confirm(con_handle); 3943 } 3944 3945 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3946 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3947 if (!sm_conn) return; // wrong connection 3948 sm_reset_tk(); 3949 big_endian_store_32(setup->sm_tk, 12, passkey); 3950 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3951 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3952 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3953 } 3954 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3955 memcpy(setup->sm_ra, setup->sm_tk, 16); 3956 memcpy(setup->sm_rb, setup->sm_tk, 16); 3957 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3958 sm_sc_start_calculating_local_confirm(sm_conn); 3959 } 3960 #endif 3961 sm_run(); 3962 } 3963 3964 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3965 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3966 if (!sm_conn) return; // wrong connection 3967 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3968 setup->sm_keypress_notification = action; 3969 sm_run(); 3970 } 3971 3972 /** 3973 * @brief Identify device in LE Device DB 3974 * @param handle 3975 * @returns index from le_device_db or -1 if not found/identified 3976 */ 3977 int sm_le_device_index(hci_con_handle_t con_handle ){ 3978 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3979 if (!sm_conn) return -1; 3980 return sm_conn->sm_le_db_index; 3981 } 3982 3983 static int gap_random_address_type_requires_updates(void){ 3984 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3985 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3986 return 1; 3987 } 3988 3989 static uint8_t own_address_type(void){ 3990 switch (gap_random_adress_type){ 3991 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3992 return BD_ADDR_TYPE_LE_PUBLIC; 3993 default: 3994 return BD_ADDR_TYPE_LE_RANDOM; 3995 } 3996 } 3997 3998 // GAP LE API 3999 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4000 gap_random_address_update_stop(); 4001 gap_random_adress_type = random_address_type; 4002 hci_le_set_own_address_type(own_address_type()); 4003 if (!gap_random_address_type_requires_updates()) return; 4004 gap_random_address_update_start(); 4005 gap_random_address_trigger(); 4006 } 4007 4008 gap_random_address_type_t gap_random_address_get_mode(void){ 4009 return gap_random_adress_type; 4010 } 4011 4012 void gap_random_address_set_update_period(int period_ms){ 4013 gap_random_adress_update_period = period_ms; 4014 if (!gap_random_address_type_requires_updates()) return; 4015 gap_random_address_update_stop(); 4016 gap_random_address_update_start(); 4017 } 4018 4019 void gap_random_address_set(bd_addr_t addr){ 4020 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4021 memcpy(sm_random_address, addr, 6); 4022 if (rau_state == RAU_W4_WORKING) return; 4023 rau_state = RAU_SET_ADDRESS; 4024 sm_run(); 4025 } 4026 4027 #ifdef ENABLE_LE_PERIPHERAL 4028 /* 4029 * @brief Set Advertisement Paramters 4030 * @param adv_int_min 4031 * @param adv_int_max 4032 * @param adv_type 4033 * @param direct_address_type 4034 * @param direct_address 4035 * @param channel_map 4036 * @param filter_policy 4037 * 4038 * @note own_address_type is used from gap_random_address_set_mode 4039 */ 4040 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4041 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4042 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4043 direct_address_typ, direct_address, channel_map, filter_policy); 4044 } 4045 #endif 4046 4047