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 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "hci_dump.h" 52 #include "l2cap.h" 53 54 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 55 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 56 #endif 57 58 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 59 #define IS_RESPONDER(role) (role) 60 #else 61 #ifdef ENABLE_LE_CENTRAL 62 // only central - never responder (avoid 'unused variable' warnings) 63 #define IS_RESPONDER(role) (0 && role) 64 #else 65 // only peripheral - always responder (avoid 'unused variable' warnings) 66 #define IS_RESPONDER(role) (1 || role) 67 #endif 68 #endif 69 70 #ifdef ENABLE_LE_SECURE_CONNECTIONS 71 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 72 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 73 #else 74 #define USE_MBEDTLS_FOR_ECDH 75 #endif 76 #endif 77 78 // Software ECDH implementation provided by mbedtls 79 #ifdef USE_MBEDTLS_FOR_ECDH 80 #include "mbedtls/config.h" 81 #include "mbedtls/platform.h" 82 #include "mbedtls/ecp.h" 83 #include "sm_mbedtls_allocator.h" 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define ENABLE_CMAC_ENGINE 88 #endif 89 90 // 91 // SM internal types and globals 92 // 93 94 typedef enum { 95 DKG_W4_WORKING, 96 DKG_CALC_IRK, 97 DKG_W4_IRK, 98 DKG_CALC_DHK, 99 DKG_W4_DHK, 100 DKG_READY 101 } derived_key_generation_t; 102 103 typedef enum { 104 RAU_W4_WORKING, 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 OK_BOTH_INPUT, // Only input on both, both input PK 128 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on both sides 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_W4_KEY, 160 EC_KEY_GENERATION_DONE, 161 } ec_key_generation_state_t; 162 163 typedef enum { 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 165 } sm_state_var_t; 166 167 // 168 // GLOBAL DATA 169 // 170 171 static uint8_t test_use_fixed_local_csrk; 172 173 // configuration 174 static uint8_t sm_accepted_stk_generation_methods; 175 static uint8_t sm_max_encryption_key_size; 176 static uint8_t sm_min_encryption_key_size; 177 static uint8_t sm_auth_req = 0; 178 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 179 static uint8_t sm_slave_request_security; 180 #ifdef ENABLE_LE_SECURE_CONNECTIONS 181 static uint8_t sm_have_ec_keypair; 182 #endif 183 184 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 185 static sm_key_t sm_persistent_er; 186 static sm_key_t sm_persistent_ir; 187 188 // derived from sm_persistent_ir 189 static sm_key_t sm_persistent_dhk; 190 static sm_key_t sm_persistent_irk; 191 static uint8_t sm_persistent_irk_ready = 0; // used for testing 192 static derived_key_generation_t dkg_state; 193 194 // derived from sm_persistent_er 195 // .. 196 197 // random address update 198 static random_address_update_t rau_state; 199 static bd_addr_t sm_random_address; 200 201 // CMAC Calculation: General 202 #ifdef ENABLE_CMAC_ENGINE 203 static cmac_state_t sm_cmac_state; 204 static uint16_t sm_cmac_message_len; 205 static sm_key_t sm_cmac_k; 206 static sm_key_t sm_cmac_x; 207 static sm_key_t sm_cmac_m_last; 208 static uint8_t sm_cmac_block_current; 209 static uint8_t sm_cmac_block_count; 210 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 211 static void (*sm_cmac_done_handler)(uint8_t * hash); 212 #endif 213 214 // CMAC for ATT Signed Writes 215 #ifdef ENABLE_LE_SIGNED_WRITE 216 static uint8_t sm_cmac_header[3]; 217 static const uint8_t * sm_cmac_message; 218 static uint8_t sm_cmac_sign_counter[4]; 219 #endif 220 221 // CMAC for Secure Connection functions 222 #ifdef ENABLE_LE_SECURE_CONNECTIONS 223 static sm_connection_t * sm_cmac_connection; 224 static uint8_t sm_cmac_sc_buffer[80]; 225 #endif 226 227 // resolvable private address lookup / CSRK calculation 228 static int sm_address_resolution_test; 229 static int sm_address_resolution_ah_calculation_active; 230 static uint8_t sm_address_resolution_addr_type; 231 static bd_addr_t sm_address_resolution_address; 232 static void * sm_address_resolution_context; 233 static address_resolution_mode_t sm_address_resolution_mode; 234 static btstack_linked_list_t sm_address_resolution_general_queue; 235 236 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 237 static sm_aes128_state_t sm_aes128_state; 238 static void * sm_aes128_context; 239 240 // random engine. store context (ususally sm_connection_t) 241 static void * sm_random_context; 242 243 // to receive hci events 244 static btstack_packet_callback_registration_t hci_event_callback_registration; 245 246 /* to dispatch sm event */ 247 static btstack_linked_list_t sm_event_handlers; 248 249 // LE Secure Connections 250 #ifdef ENABLE_LE_SECURE_CONNECTIONS 251 static ec_key_generation_state_t ec_key_generation_state; 252 static uint8_t ec_d[32]; 253 static uint8_t ec_qx[32]; 254 static uint8_t ec_qy[32]; 255 #endif 256 257 // Software ECDH implementation provided by mbedtls 258 #ifdef USE_MBEDTLS_FOR_ECDH 259 // group is always valid 260 static mbedtls_ecp_group mbedtls_ec_group; 261 #ifndef HAVE_MALLOC 262 // COMP Method with Window 2 263 // 1300 bytes with 23 allocations 264 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 265 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 266 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 267 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 268 #endif 269 #endif 270 271 // 272 // Volume 3, Part H, Chapter 24 273 // "Security shall be initiated by the Security Manager in the device in the master role. 274 // The device in the slave role shall be the responding device." 275 // -> master := initiator, slave := responder 276 // 277 278 // data needed for security setup 279 typedef struct sm_setup_context { 280 281 btstack_timer_source_t sm_timeout; 282 283 // used in all phases 284 uint8_t sm_pairing_failed_reason; 285 286 // user response, (Phase 1 and/or 2) 287 uint8_t sm_user_response; 288 uint8_t sm_keypress_notification; 289 290 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 291 int sm_key_distribution_send_set; 292 int sm_key_distribution_received_set; 293 294 // Phase 2 (Pairing over SMP) 295 stk_generation_method_t sm_stk_generation_method; 296 sm_key_t sm_tk; 297 uint8_t sm_use_secure_connections; 298 299 sm_key_t sm_c1_t3_value; // c1 calculation 300 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 301 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 302 sm_key_t sm_local_random; 303 sm_key_t sm_local_confirm; 304 sm_key_t sm_peer_random; 305 sm_key_t sm_peer_confirm; 306 uint8_t sm_m_addr_type; // address and type can be removed 307 uint8_t sm_s_addr_type; // '' 308 bd_addr_t sm_m_address; // '' 309 bd_addr_t sm_s_address; // '' 310 sm_key_t sm_ltk; 311 312 uint8_t sm_state_vars; 313 #ifdef ENABLE_LE_SECURE_CONNECTIONS 314 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 315 uint8_t sm_peer_qy[32]; // '' 316 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 317 sm_key_t sm_local_nonce; // might be combined with sm_local_random 318 sm_key_t sm_peer_dhkey_check; 319 sm_key_t sm_local_dhkey_check; 320 sm_key_t sm_ra; 321 sm_key_t sm_rb; 322 sm_key_t sm_t; // used for f5 and h6 323 sm_key_t sm_mackey; 324 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 325 #endif 326 327 // Phase 3 328 329 // key distribution, we generate 330 uint16_t sm_local_y; 331 uint16_t sm_local_div; 332 uint16_t sm_local_ediv; 333 uint8_t sm_local_rand[8]; 334 sm_key_t sm_local_ltk; 335 sm_key_t sm_local_csrk; 336 sm_key_t sm_local_irk; 337 // sm_local_address/addr_type not needed 338 339 // key distribution, received from peer 340 uint16_t sm_peer_y; 341 uint16_t sm_peer_div; 342 uint16_t sm_peer_ediv; 343 uint8_t sm_peer_rand[8]; 344 sm_key_t sm_peer_ltk; 345 sm_key_t sm_peer_irk; 346 sm_key_t sm_peer_csrk; 347 uint8_t sm_peer_addr_type; 348 bd_addr_t sm_peer_address; 349 350 } sm_setup_context_t; 351 352 // 353 static sm_setup_context_t the_setup; 354 static sm_setup_context_t * setup = &the_setup; 355 356 // active connection - the one for which the_setup is used for 357 static uint16_t sm_active_connection = 0; 358 359 // @returns 1 if oob data is available 360 // stores oob data in provided 16 byte buffer if not null 361 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 362 363 // horizontal: initiator capabilities 364 // vertial: responder capabilities 365 static const stk_generation_method_t stk_generation_method [5] [5] = { 366 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 367 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 368 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 369 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 370 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 371 }; 372 373 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 374 #ifdef ENABLE_LE_SECURE_CONNECTIONS 375 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 376 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 377 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 378 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 379 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 380 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 381 }; 382 #endif 383 384 static void sm_run(void); 385 static void sm_done_for_handle(hci_con_handle_t con_handle); 386 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 387 static inline int sm_calc_actual_encryption_key_size(int other); 388 static int sm_validate_stk_generation_method(void); 389 390 static void log_info_hex16(const char * name, uint16_t value){ 391 log_info("%-6s 0x%04x", name, value); 392 } 393 394 // @returns 1 if all bytes are 0 395 static int sm_is_null(uint8_t * data, int size){ 396 int i; 397 for (i=0; i < size ; i++){ 398 if (data[i]) return 0; 399 } 400 return 1; 401 } 402 403 static int sm_is_null_random(uint8_t random[8]){ 404 return sm_is_null(random, 8); 405 } 406 407 static int sm_is_null_key(uint8_t * key){ 408 return sm_is_null(key, 16); 409 } 410 411 // Key utils 412 static void sm_reset_tk(void){ 413 int i; 414 for (i=0;i<16;i++){ 415 setup->sm_tk[i] = 0; 416 } 417 } 418 419 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 420 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 421 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 422 int i; 423 for (i = max_encryption_size ; i < 16 ; i++){ 424 key[15-i] = 0; 425 } 426 } 427 428 // SMP Timeout implementation 429 430 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 431 // the Security Manager Timer shall be reset and started. 432 // 433 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 434 // 435 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 436 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 437 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 438 // established. 439 440 static void sm_timeout_handler(btstack_timer_source_t * timer){ 441 log_info("SM timeout"); 442 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 443 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 444 sm_done_for_handle(sm_conn->sm_handle); 445 446 // trigger handling of next ready connection 447 sm_run(); 448 } 449 static void sm_timeout_start(sm_connection_t * sm_conn){ 450 btstack_run_loop_remove_timer(&setup->sm_timeout); 451 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 452 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 453 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 454 btstack_run_loop_add_timer(&setup->sm_timeout); 455 } 456 static void sm_timeout_stop(void){ 457 btstack_run_loop_remove_timer(&setup->sm_timeout); 458 } 459 static void sm_timeout_reset(sm_connection_t * sm_conn){ 460 sm_timeout_stop(); 461 sm_timeout_start(sm_conn); 462 } 463 464 // end of sm timeout 465 466 // GAP Random Address updates 467 static gap_random_address_type_t gap_random_adress_type; 468 static btstack_timer_source_t gap_random_address_update_timer; 469 static uint32_t gap_random_adress_update_period; 470 471 static void gap_random_address_trigger(void){ 472 if (rau_state != RAU_IDLE) return; 473 log_info("gap_random_address_trigger"); 474 rau_state = RAU_GET_RANDOM; 475 sm_run(); 476 } 477 478 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 479 UNUSED(timer); 480 481 log_info("GAP Random Address Update due"); 482 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 483 btstack_run_loop_add_timer(&gap_random_address_update_timer); 484 gap_random_address_trigger(); 485 } 486 487 static void gap_random_address_update_start(void){ 488 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 489 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 490 btstack_run_loop_add_timer(&gap_random_address_update_timer); 491 } 492 493 static void gap_random_address_update_stop(void){ 494 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 495 } 496 497 498 static void sm_random_start(void * context){ 499 sm_random_context = context; 500 hci_send_cmd(&hci_le_rand); 501 } 502 503 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 504 // context is made availabe to aes128 result handler by this 505 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 506 sm_aes128_state = SM_AES128_ACTIVE; 507 sm_key_t key_flipped, plaintext_flipped; 508 reverse_128(key, key_flipped); 509 reverse_128(plaintext, plaintext_flipped); 510 sm_aes128_context = context; 511 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 512 } 513 514 // ah(k,r) helper 515 // r = padding || r 516 // r - 24 bit value 517 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 518 // r'= padding || r 519 memset(r_prime, 0, 16); 520 memcpy(&r_prime[13], r, 3); 521 } 522 523 // d1 helper 524 // d' = padding || r || d 525 // d,r - 16 bit values 526 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 527 // d'= padding || r || d 528 memset(d1_prime, 0, 16); 529 big_endian_store_16(d1_prime, 12, r); 530 big_endian_store_16(d1_prime, 14, d); 531 } 532 533 // dm helper 534 // r’ = padding || r 535 // r - 64 bit value 536 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 537 memset(r_prime, 0, 16); 538 memcpy(&r_prime[8], r, 8); 539 } 540 541 // calculate arguments for first AES128 operation in C1 function 542 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){ 543 544 // p1 = pres || preq || rat’ || iat’ 545 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 546 // cant octet of pres becomes the most significant octet of p1. 547 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 548 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 549 // p1 is 0x05000800000302070710000001010001." 550 551 sm_key_t p1; 552 reverse_56(pres, &p1[0]); 553 reverse_56(preq, &p1[7]); 554 p1[14] = rat; 555 p1[15] = iat; 556 log_info_key("p1", p1); 557 log_info_key("r", r); 558 559 // t1 = r xor p1 560 int i; 561 for (i=0;i<16;i++){ 562 t1[i] = r[i] ^ p1[i]; 563 } 564 log_info_key("t1", t1); 565 } 566 567 // calculate arguments for second AES128 operation in C1 function 568 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 569 // p2 = padding || ia || ra 570 // "The least significant octet of ra becomes the least significant octet of p2 and 571 // the most significant octet of padding becomes the most significant octet of p2. 572 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 573 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 574 575 sm_key_t p2; 576 memset(p2, 0, 16); 577 memcpy(&p2[4], ia, 6); 578 memcpy(&p2[10], ra, 6); 579 log_info_key("p2", p2); 580 581 // c1 = e(k, t2_xor_p2) 582 int i; 583 for (i=0;i<16;i++){ 584 t3[i] = t2[i] ^ p2[i]; 585 } 586 log_info_key("t3", t3); 587 } 588 589 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 590 log_info_key("r1", r1); 591 log_info_key("r2", r2); 592 memcpy(&r_prime[8], &r2[8], 8); 593 memcpy(&r_prime[0], &r1[8], 8); 594 } 595 596 #ifdef ENABLE_LE_SECURE_CONNECTIONS 597 // Software implementations of crypto toolbox for LE Secure Connection 598 // TODO: replace with code to use AES Engine of HCI Controller 599 typedef uint8_t sm_key24_t[3]; 600 typedef uint8_t sm_key56_t[7]; 601 typedef uint8_t sm_key256_t[32]; 602 603 #if 0 604 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 605 uint32_t rk[RKLENGTH(KEYBITS)]; 606 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 607 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 608 } 609 610 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 611 memcpy(k1, k0, 16); 612 sm_shift_left_by_one_bit_inplace(16, k1); 613 if (k0[0] & 0x80){ 614 k1[15] ^= 0x87; 615 } 616 memcpy(k2, k1, 16); 617 sm_shift_left_by_one_bit_inplace(16, k2); 618 if (k1[0] & 0x80){ 619 k2[15] ^= 0x87; 620 } 621 } 622 623 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 624 sm_key_t k0, k1, k2, zero; 625 memset(zero, 0, 16); 626 627 aes128_calc_cyphertext(key, zero, k0); 628 calc_subkeys(k0, k1, k2); 629 630 int cmac_block_count = (cmac_message_len + 15) / 16; 631 632 // step 3: .. 633 if (cmac_block_count==0){ 634 cmac_block_count = 1; 635 } 636 637 // step 4: set m_last 638 sm_key_t cmac_m_last; 639 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 640 int i; 641 if (sm_cmac_last_block_complete){ 642 for (i=0;i<16;i++){ 643 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 644 } 645 } else { 646 int valid_octets_in_last_block = cmac_message_len & 0x0f; 647 for (i=0;i<16;i++){ 648 if (i < valid_octets_in_last_block){ 649 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 650 continue; 651 } 652 if (i == valid_octets_in_last_block){ 653 cmac_m_last[i] = 0x80 ^ k2[i]; 654 continue; 655 } 656 cmac_m_last[i] = k2[i]; 657 } 658 } 659 660 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 661 // LOG_KEY(cmac_m_last); 662 663 // Step 5 664 sm_key_t cmac_x; 665 memset(cmac_x, 0, 16); 666 667 // Step 6 668 sm_key_t sm_cmac_y; 669 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 670 for (i=0;i<16;i++){ 671 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 672 } 673 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 674 } 675 for (i=0;i<16;i++){ 676 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 677 } 678 679 // Step 7 680 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 681 } 682 #endif 683 #endif 684 685 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){ 686 event[0] = type; 687 event[1] = event_size - 2; 688 little_endian_store_16(event, 2, con_handle); 689 event[4] = addr_type; 690 reverse_bd_addr(address, &event[5]); 691 } 692 693 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 694 UNUSED(channel); 695 696 // log event 697 hci_dump_packet(packet_type, 1, packet, size); 698 // dispatch to all event handlers 699 btstack_linked_list_iterator_t it; 700 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 701 while (btstack_linked_list_iterator_has_next(&it)){ 702 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 703 entry->callback(packet_type, 0, packet, size); 704 } 705 } 706 707 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 708 uint8_t event[11]; 709 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 710 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 711 } 712 713 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){ 714 uint8_t event[15]; 715 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 716 little_endian_store_32(event, 11, passkey); 717 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 718 } 719 720 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){ 721 // fetch addr and addr type from db 722 bd_addr_t identity_address; 723 int identity_address_type; 724 le_device_db_info(index, &identity_address_type, identity_address, NULL); 725 726 uint8_t event[19]; 727 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 728 event[11] = identity_address_type; 729 reverse_bd_addr(identity_address, &event[12]); 730 event[18] = index; 731 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 732 } 733 734 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){ 735 736 uint8_t event[18]; 737 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 738 event[11] = result; 739 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 740 } 741 742 // decide on stk generation based on 743 // - pairing request 744 // - io capabilities 745 // - OOB data availability 746 static void sm_setup_tk(void){ 747 748 // default: just works 749 setup->sm_stk_generation_method = JUST_WORKS; 750 751 #ifdef ENABLE_LE_SECURE_CONNECTIONS 752 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 753 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 754 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 755 memset(setup->sm_ra, 0, 16); 756 memset(setup->sm_rb, 0, 16); 757 #else 758 setup->sm_use_secure_connections = 0; 759 #endif 760 761 // If both devices have not set the MITM option in the Authentication Requirements 762 // Flags, then the IO capabilities shall be ignored and the Just Works association 763 // model shall be used. 764 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 765 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 766 log_info("SM: MITM not required by both -> JUST WORKS"); 767 return; 768 } 769 770 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 771 772 // If both devices have out of band authentication data, then the Authentication 773 // Requirements Flags shall be ignored when selecting the pairing method and the 774 // Out of Band pairing method shall be used. 775 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 776 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 777 log_info("SM: have OOB data"); 778 log_info_key("OOB", setup->sm_tk); 779 setup->sm_stk_generation_method = OOB; 780 return; 781 } 782 783 // Reset TK as it has been setup in sm_init_setup 784 sm_reset_tk(); 785 786 // Also use just works if unknown io capabilites 787 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)){ 788 return; 789 } 790 791 // Otherwise the IO capabilities of the devices shall be used to determine the 792 // pairing method as defined in Table 2.4. 793 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 794 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 795 796 #ifdef ENABLE_LE_SECURE_CONNECTIONS 797 // table not define by default 798 if (setup->sm_use_secure_connections){ 799 generation_method = stk_generation_method_with_secure_connection; 800 } 801 #endif 802 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)]; 803 804 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 805 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); 806 } 807 808 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 809 int flags = 0; 810 if (key_set & SM_KEYDIST_ENC_KEY){ 811 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 812 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 813 } 814 if (key_set & SM_KEYDIST_ID_KEY){ 815 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 816 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 817 } 818 if (key_set & SM_KEYDIST_SIGN){ 819 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 820 } 821 return flags; 822 } 823 824 static void sm_setup_key_distribution(uint8_t key_set){ 825 setup->sm_key_distribution_received_set = 0; 826 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 827 } 828 829 // CSRK Key Lookup 830 831 832 static int sm_address_resolution_idle(void){ 833 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 834 } 835 836 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){ 837 memcpy(sm_address_resolution_address, addr, 6); 838 sm_address_resolution_addr_type = addr_type; 839 sm_address_resolution_test = 0; 840 sm_address_resolution_mode = mode; 841 sm_address_resolution_context = context; 842 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 843 } 844 845 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 846 // check if already in list 847 btstack_linked_list_iterator_t it; 848 sm_lookup_entry_t * entry; 849 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 850 while(btstack_linked_list_iterator_has_next(&it)){ 851 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 852 if (entry->address_type != address_type) continue; 853 if (memcmp(entry->address, address, 6)) continue; 854 // already in list 855 return BTSTACK_BUSY; 856 } 857 entry = btstack_memory_sm_lookup_entry_get(); 858 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 859 entry->address_type = (bd_addr_type_t) address_type; 860 memcpy(entry->address, address, 6); 861 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 862 sm_run(); 863 return 0; 864 } 865 866 // 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 867 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 868 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 869 } 870 static inline void dkg_next_state(void){ 871 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 872 } 873 static inline void rau_next_state(void){ 874 rau_state = (random_address_update_t) (((int)rau_state) + 1); 875 } 876 877 // CMAC calculation using AES Engine 878 #ifdef ENABLE_CMAC_ENGINE 879 880 static inline void sm_cmac_next_state(void){ 881 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 882 } 883 884 static int sm_cmac_last_block_complete(void){ 885 if (sm_cmac_message_len == 0) return 0; 886 return (sm_cmac_message_len & 0x0f) == 0; 887 } 888 889 int sm_cmac_ready(void){ 890 return sm_cmac_state == CMAC_IDLE; 891 } 892 893 // generic cmac calculation 894 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])){ 895 // Generalized CMAC 896 memcpy(sm_cmac_k, key, 16); 897 memset(sm_cmac_x, 0, 16); 898 sm_cmac_block_current = 0; 899 sm_cmac_message_len = message_len; 900 sm_cmac_done_handler = done_callback; 901 sm_cmac_get_byte = get_byte_callback; 902 903 // step 2: n := ceil(len/const_Bsize); 904 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 905 906 // step 3: .. 907 if (sm_cmac_block_count==0){ 908 sm_cmac_block_count = 1; 909 } 910 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 911 912 // first, we need to compute l for k1, k2, and m_last 913 sm_cmac_state = CMAC_CALC_SUBKEYS; 914 915 // let's go 916 sm_run(); 917 } 918 #endif 919 920 // cmac for ATT Message signing 921 #ifdef ENABLE_LE_SIGNED_WRITE 922 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 923 if (offset >= sm_cmac_message_len) { 924 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 925 return 0; 926 } 927 928 offset = sm_cmac_message_len - 1 - offset; 929 930 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 931 if (offset < 3){ 932 return sm_cmac_header[offset]; 933 } 934 int actual_message_len_incl_header = sm_cmac_message_len - 4; 935 if (offset < actual_message_len_incl_header){ 936 return sm_cmac_message[offset - 3]; 937 } 938 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 939 } 940 941 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)){ 942 // ATT Message Signing 943 sm_cmac_header[0] = opcode; 944 little_endian_store_16(sm_cmac_header, 1, con_handle); 945 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 946 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 947 sm_cmac_message = message; 948 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 949 } 950 #endif 951 952 #ifdef ENABLE_CMAC_ENGINE 953 static void sm_cmac_handle_aes_engine_ready(void){ 954 switch (sm_cmac_state){ 955 case CMAC_CALC_SUBKEYS: { 956 sm_key_t const_zero; 957 memset(const_zero, 0, 16); 958 sm_cmac_next_state(); 959 sm_aes128_start(sm_cmac_k, const_zero, NULL); 960 break; 961 } 962 case CMAC_CALC_MI: { 963 int j; 964 sm_key_t y; 965 for (j=0;j<16;j++){ 966 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 967 } 968 sm_cmac_block_current++; 969 sm_cmac_next_state(); 970 sm_aes128_start(sm_cmac_k, y, NULL); 971 break; 972 } 973 case CMAC_CALC_MLAST: { 974 int i; 975 sm_key_t y; 976 for (i=0;i<16;i++){ 977 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 978 } 979 log_info_key("Y", y); 980 sm_cmac_block_current++; 981 sm_cmac_next_state(); 982 sm_aes128_start(sm_cmac_k, y, NULL); 983 break; 984 } 985 default: 986 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 987 break; 988 } 989 } 990 991 // CMAC Implementation using AES128 engine 992 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 993 int i; 994 int carry = 0; 995 for (i=len-1; i >= 0 ; i--){ 996 int new_carry = data[i] >> 7; 997 data[i] = data[i] << 1 | carry; 998 carry = new_carry; 999 } 1000 } 1001 1002 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1003 switch (sm_cmac_state){ 1004 case CMAC_W4_SUBKEYS: { 1005 sm_key_t k1; 1006 memcpy(k1, data, 16); 1007 sm_shift_left_by_one_bit_inplace(16, k1); 1008 if (data[0] & 0x80){ 1009 k1[15] ^= 0x87; 1010 } 1011 sm_key_t k2; 1012 memcpy(k2, k1, 16); 1013 sm_shift_left_by_one_bit_inplace(16, k2); 1014 if (k1[0] & 0x80){ 1015 k2[15] ^= 0x87; 1016 } 1017 1018 log_info_key("k", sm_cmac_k); 1019 log_info_key("k1", k1); 1020 log_info_key("k2", k2); 1021 1022 // step 4: set m_last 1023 int i; 1024 if (sm_cmac_last_block_complete()){ 1025 for (i=0;i<16;i++){ 1026 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1027 } 1028 } else { 1029 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1030 for (i=0;i<16;i++){ 1031 if (i < valid_octets_in_last_block){ 1032 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1033 continue; 1034 } 1035 if (i == valid_octets_in_last_block){ 1036 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1037 continue; 1038 } 1039 sm_cmac_m_last[i] = k2[i]; 1040 } 1041 } 1042 1043 // next 1044 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1045 break; 1046 } 1047 case CMAC_W4_MI: 1048 memcpy(sm_cmac_x, data, 16); 1049 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1050 break; 1051 case CMAC_W4_MLAST: 1052 // done 1053 log_info("Setting CMAC Engine to IDLE"); 1054 sm_cmac_state = CMAC_IDLE; 1055 log_info_key("CMAC", data); 1056 sm_cmac_done_handler(data); 1057 break; 1058 default: 1059 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1060 break; 1061 } 1062 } 1063 #endif 1064 1065 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1066 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1067 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1068 switch (setup->sm_stk_generation_method){ 1069 case PK_RESP_INPUT: 1070 if (IS_RESPONDER(sm_conn->sm_role)){ 1071 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1072 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1073 } else { 1074 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)); 1075 } 1076 break; 1077 case PK_INIT_INPUT: 1078 if (IS_RESPONDER(sm_conn->sm_role)){ 1079 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)); 1080 } else { 1081 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1082 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1083 } 1084 break; 1085 case OK_BOTH_INPUT: 1086 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1087 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1088 break; 1089 case NK_BOTH_INPUT: 1090 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1091 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)); 1092 break; 1093 case JUST_WORKS: 1094 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1095 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1096 break; 1097 case OOB: 1098 // client already provided OOB data, let's skip notification. 1099 break; 1100 } 1101 } 1102 1103 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1104 int recv_flags; 1105 if (IS_RESPONDER(sm_conn->sm_role)){ 1106 // slave / responder 1107 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1108 } else { 1109 // master / initiator 1110 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1111 } 1112 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1113 return recv_flags == setup->sm_key_distribution_received_set; 1114 } 1115 1116 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1117 if (sm_active_connection == con_handle){ 1118 sm_timeout_stop(); 1119 sm_active_connection = 0; 1120 log_info("sm: connection 0x%x released setup context", con_handle); 1121 } 1122 } 1123 1124 static int sm_key_distribution_flags_for_auth_req(void){ 1125 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1126 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1127 // encryption information only if bonding requested 1128 flags |= SM_KEYDIST_ENC_KEY; 1129 } 1130 return flags; 1131 } 1132 1133 static void sm_reset_setup(void){ 1134 // fill in sm setup 1135 setup->sm_state_vars = 0; 1136 setup->sm_keypress_notification = 0xff; 1137 sm_reset_tk(); 1138 } 1139 1140 static void sm_init_setup(sm_connection_t * sm_conn){ 1141 1142 // fill in sm setup 1143 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1144 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1145 1146 // query client for OOB data 1147 int have_oob_data = 0; 1148 if (sm_get_oob_data) { 1149 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1150 } 1151 1152 sm_pairing_packet_t * local_packet; 1153 if (IS_RESPONDER(sm_conn->sm_role)){ 1154 // slave 1155 local_packet = &setup->sm_s_pres; 1156 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1157 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1158 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1159 } else { 1160 // master 1161 local_packet = &setup->sm_m_preq; 1162 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1163 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1164 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1165 1166 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1167 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1168 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1169 } 1170 1171 uint8_t auth_req = sm_auth_req; 1172 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1173 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1174 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1175 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1176 } 1177 1178 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1179 1180 sm_pairing_packet_t * remote_packet; 1181 int remote_key_request; 1182 if (IS_RESPONDER(sm_conn->sm_role)){ 1183 // slave / responder 1184 remote_packet = &setup->sm_m_preq; 1185 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1186 } else { 1187 // master / initiator 1188 remote_packet = &setup->sm_s_pres; 1189 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1190 } 1191 1192 // check key size 1193 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1194 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1195 1196 // decide on STK generation method 1197 sm_setup_tk(); 1198 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1199 1200 // check if STK generation method is acceptable by client 1201 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1202 1203 // identical to responder 1204 sm_setup_key_distribution(remote_key_request); 1205 1206 // JUST WORKS doens't provide authentication 1207 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1208 1209 return 0; 1210 } 1211 1212 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1213 1214 // cache and reset context 1215 int matched_device_id = sm_address_resolution_test; 1216 address_resolution_mode_t mode = sm_address_resolution_mode; 1217 void * context = sm_address_resolution_context; 1218 1219 // reset context 1220 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1221 sm_address_resolution_context = NULL; 1222 sm_address_resolution_test = -1; 1223 hci_con_handle_t con_handle = 0; 1224 1225 sm_connection_t * sm_connection; 1226 #ifdef ENABLE_LE_CENTRAL 1227 sm_key_t ltk; 1228 #endif 1229 switch (mode){ 1230 case ADDRESS_RESOLUTION_GENERAL: 1231 break; 1232 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1233 sm_connection = (sm_connection_t *) context; 1234 con_handle = sm_connection->sm_handle; 1235 switch (event){ 1236 case ADDRESS_RESOLUTION_SUCEEDED: 1237 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1238 sm_connection->sm_le_db_index = matched_device_id; 1239 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1240 #ifdef ENABLE_LE_CENTRAL 1241 if (sm_connection->sm_role) break; 1242 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1243 sm_connection->sm_security_request_received = 0; 1244 sm_connection->sm_bonding_requested = 0; 1245 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1246 if (!sm_is_null_key(ltk)){ 1247 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1248 } else { 1249 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1250 } 1251 #endif 1252 break; 1253 case ADDRESS_RESOLUTION_FAILED: 1254 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1255 #ifdef ENABLE_LE_CENTRAL 1256 if (sm_connection->sm_role) break; 1257 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1258 sm_connection->sm_security_request_received = 0; 1259 sm_connection->sm_bonding_requested = 0; 1260 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1261 #endif 1262 break; 1263 } 1264 break; 1265 default: 1266 break; 1267 } 1268 1269 switch (event){ 1270 case ADDRESS_RESOLUTION_SUCEEDED: 1271 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1272 break; 1273 case ADDRESS_RESOLUTION_FAILED: 1274 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1275 break; 1276 } 1277 } 1278 1279 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1280 1281 int le_db_index = -1; 1282 1283 // lookup device based on IRK 1284 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1285 int i; 1286 for (i=0; i < le_device_db_count(); i++){ 1287 sm_key_t irk; 1288 bd_addr_t address; 1289 int address_type; 1290 le_device_db_info(i, &address_type, address, irk); 1291 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1292 log_info("sm: device found for IRK, updating"); 1293 le_db_index = i; 1294 break; 1295 } 1296 } 1297 } 1298 1299 // if not found, lookup via public address if possible 1300 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1301 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1302 int i; 1303 for (i=0; i < le_device_db_count(); i++){ 1304 bd_addr_t address; 1305 int address_type; 1306 le_device_db_info(i, &address_type, address, NULL); 1307 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1308 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1309 log_info("sm: device found for public address, updating"); 1310 le_db_index = i; 1311 break; 1312 } 1313 } 1314 } 1315 1316 // if not found, add to db 1317 if (le_db_index < 0) { 1318 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1319 } 1320 1321 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1322 1323 if (le_db_index >= 0){ 1324 1325 // store local CSRK 1326 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1327 log_info("sm: store local CSRK"); 1328 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1329 le_device_db_local_counter_set(le_db_index, 0); 1330 } 1331 1332 // store remote CSRK 1333 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1334 log_info("sm: store remote CSRK"); 1335 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1336 le_device_db_remote_counter_set(le_db_index, 0); 1337 } 1338 1339 // store encryption information for secure connections: LTK generated by ECDH 1340 if (setup->sm_use_secure_connections){ 1341 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1342 uint8_t zero_rand[8]; 1343 memset(zero_rand, 0, 8); 1344 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1345 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1346 } 1347 1348 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1349 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1350 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1351 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1352 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1353 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1354 1355 } 1356 } 1357 1358 // keep le_db_index 1359 sm_conn->sm_le_db_index = le_db_index; 1360 } 1361 1362 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1363 setup->sm_pairing_failed_reason = reason; 1364 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1365 } 1366 1367 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1368 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1369 } 1370 1371 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1372 1373 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1374 static int sm_passkey_used(stk_generation_method_t method); 1375 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1376 1377 static void sm_log_ec_keypair(void){ 1378 log_info("Elliptic curve: X"); 1379 log_info_hexdump(ec_qx,32); 1380 log_info("Elliptic curve: Y"); 1381 log_info_hexdump(ec_qy,32); 1382 } 1383 1384 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1385 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1386 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1387 } else { 1388 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1389 } 1390 } 1391 1392 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1393 if (IS_RESPONDER(sm_conn->sm_role)){ 1394 // Responder 1395 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1396 } else { 1397 // Initiator role 1398 switch (setup->sm_stk_generation_method){ 1399 case JUST_WORKS: 1400 sm_sc_prepare_dhkey_check(sm_conn); 1401 break; 1402 1403 case NK_BOTH_INPUT: 1404 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1405 break; 1406 case PK_INIT_INPUT: 1407 case PK_RESP_INPUT: 1408 case OK_BOTH_INPUT: 1409 if (setup->sm_passkey_bit < 20) { 1410 sm_sc_start_calculating_local_confirm(sm_conn); 1411 } else { 1412 sm_sc_prepare_dhkey_check(sm_conn); 1413 } 1414 break; 1415 case OOB: 1416 // TODO: implement SC OOB 1417 break; 1418 } 1419 } 1420 } 1421 1422 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1423 return sm_cmac_sc_buffer[offset]; 1424 } 1425 1426 static void sm_sc_cmac_done(uint8_t * hash){ 1427 log_info("sm_sc_cmac_done: "); 1428 log_info_hexdump(hash, 16); 1429 1430 sm_connection_t * sm_conn = sm_cmac_connection; 1431 sm_cmac_connection = NULL; 1432 link_key_type_t link_key_type; 1433 1434 switch (sm_conn->sm_engine_state){ 1435 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1436 memcpy(setup->sm_local_confirm, hash, 16); 1437 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1438 break; 1439 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1440 // check 1441 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1442 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1443 break; 1444 } 1445 sm_sc_state_after_receiving_random(sm_conn); 1446 break; 1447 case SM_SC_W4_CALCULATE_G2: { 1448 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1449 big_endian_store_32(setup->sm_tk, 12, vab); 1450 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1451 sm_trigger_user_response(sm_conn); 1452 break; 1453 } 1454 case SM_SC_W4_CALCULATE_F5_SALT: 1455 memcpy(setup->sm_t, hash, 16); 1456 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1457 break; 1458 case SM_SC_W4_CALCULATE_F5_MACKEY: 1459 memcpy(setup->sm_mackey, hash, 16); 1460 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1461 break; 1462 case SM_SC_W4_CALCULATE_F5_LTK: 1463 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1464 // Errata Service Release to the Bluetooth Specification: ESR09 1465 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1466 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1467 memcpy(setup->sm_ltk, hash, 16); 1468 memcpy(setup->sm_local_ltk, hash, 16); 1469 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1470 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1471 break; 1472 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1473 memcpy(setup->sm_local_dhkey_check, hash, 16); 1474 if (IS_RESPONDER(sm_conn->sm_role)){ 1475 // responder 1476 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1477 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1478 } else { 1479 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1480 } 1481 } else { 1482 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1483 } 1484 break; 1485 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1486 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1487 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1488 break; 1489 } 1490 if (IS_RESPONDER(sm_conn->sm_role)){ 1491 // responder 1492 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1493 } else { 1494 // initiator 1495 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1496 } 1497 break; 1498 case SM_SC_W4_CALCULATE_H6_ILK: 1499 memcpy(setup->sm_t, hash, 16); 1500 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1501 break; 1502 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1503 reverse_128(hash, setup->sm_t); 1504 link_key_type = sm_conn->sm_connection_authenticated ? 1505 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1506 if (IS_RESPONDER(sm_conn->sm_role)){ 1507 #ifdef ENABLE_CLASSIC 1508 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1509 #endif 1510 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1511 } else { 1512 #ifdef ENABLE_CLASSIC 1513 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1514 #endif 1515 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1516 } 1517 sm_done_for_handle(sm_conn->sm_handle); 1518 break; 1519 default: 1520 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1521 break; 1522 } 1523 sm_run(); 1524 } 1525 1526 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){ 1527 const uint16_t message_len = 65; 1528 sm_cmac_connection = sm_conn; 1529 memcpy(sm_cmac_sc_buffer, u, 32); 1530 memcpy(sm_cmac_sc_buffer+32, v, 32); 1531 sm_cmac_sc_buffer[64] = z; 1532 log_info("f4 key"); 1533 log_info_hexdump(x, 16); 1534 log_info("f4 message"); 1535 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1536 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1537 } 1538 1539 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1540 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1541 static const uint8_t f5_length[] = { 0x01, 0x00}; 1542 1543 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1544 #ifdef USE_MBEDTLS_FOR_ECDH 1545 // da * Pb 1546 mbedtls_mpi d; 1547 mbedtls_ecp_point Q; 1548 mbedtls_ecp_point DH; 1549 mbedtls_mpi_init(&d); 1550 mbedtls_ecp_point_init(&Q); 1551 mbedtls_ecp_point_init(&DH); 1552 mbedtls_mpi_read_binary(&d, ec_d, 32); 1553 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1554 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1555 mbedtls_mpi_lset(&Q.Z, 1); 1556 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1557 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1558 mbedtls_ecp_point_free(&DH); 1559 mbedtls_mpi_free(&d); 1560 mbedtls_ecp_point_free(&Q); 1561 #endif 1562 log_info("dhkey"); 1563 log_info_hexdump(dhkey, 32); 1564 } 1565 1566 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1567 // calculate DHKEY 1568 sm_key256_t dhkey; 1569 sm_sc_calculate_dhkey(dhkey); 1570 1571 // calculate salt for f5 1572 const uint16_t message_len = 32; 1573 sm_cmac_connection = sm_conn; 1574 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1575 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1576 } 1577 1578 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){ 1579 const uint16_t message_len = 53; 1580 sm_cmac_connection = sm_conn; 1581 1582 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1583 sm_cmac_sc_buffer[0] = 0; 1584 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1585 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1586 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1587 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1588 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1589 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1590 log_info("f5 key"); 1591 log_info_hexdump(t, 16); 1592 log_info("f5 message for MacKey"); 1593 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1594 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1595 } 1596 1597 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1598 sm_key56_t bd_addr_master, bd_addr_slave; 1599 bd_addr_master[0] = setup->sm_m_addr_type; 1600 bd_addr_slave[0] = setup->sm_s_addr_type; 1601 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1602 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1603 if (IS_RESPONDER(sm_conn->sm_role)){ 1604 // responder 1605 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1606 } else { 1607 // initiator 1608 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1609 } 1610 } 1611 1612 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1613 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1614 const uint16_t message_len = 53; 1615 sm_cmac_connection = sm_conn; 1616 sm_cmac_sc_buffer[0] = 1; 1617 // 1..52 setup before 1618 log_info("f5 key"); 1619 log_info_hexdump(t, 16); 1620 log_info("f5 message for LTK"); 1621 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1622 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1623 } 1624 1625 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1626 f5_ltk(sm_conn, setup->sm_t); 1627 } 1628 1629 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){ 1630 const uint16_t message_len = 65; 1631 sm_cmac_connection = sm_conn; 1632 memcpy(sm_cmac_sc_buffer, n1, 16); 1633 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1634 memcpy(sm_cmac_sc_buffer+32, r, 16); 1635 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1636 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1637 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1638 log_info("f6 key"); 1639 log_info_hexdump(w, 16); 1640 log_info("f6 message"); 1641 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1642 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1643 } 1644 1645 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1646 // - U is 256 bits 1647 // - V is 256 bits 1648 // - X is 128 bits 1649 // - Y is 128 bits 1650 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){ 1651 const uint16_t message_len = 80; 1652 sm_cmac_connection = sm_conn; 1653 memcpy(sm_cmac_sc_buffer, u, 32); 1654 memcpy(sm_cmac_sc_buffer+32, v, 32); 1655 memcpy(sm_cmac_sc_buffer+64, y, 16); 1656 log_info("g2 key"); 1657 log_info_hexdump(x, 16); 1658 log_info("g2 message"); 1659 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1660 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1661 } 1662 1663 static void g2_calculate(sm_connection_t * sm_conn) { 1664 // calc Va if numeric comparison 1665 if (IS_RESPONDER(sm_conn->sm_role)){ 1666 // responder 1667 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1668 } else { 1669 // initiator 1670 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1671 } 1672 } 1673 1674 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1675 uint8_t z = 0; 1676 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1677 // some form of passkey 1678 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1679 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1680 setup->sm_passkey_bit++; 1681 } 1682 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1683 } 1684 1685 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1686 uint8_t z = 0; 1687 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1688 // some form of passkey 1689 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1690 // sm_passkey_bit was increased before sending confirm value 1691 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1692 } 1693 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1694 } 1695 1696 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1697 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1698 } 1699 1700 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1701 // calculate DHKCheck 1702 sm_key56_t bd_addr_master, bd_addr_slave; 1703 bd_addr_master[0] = setup->sm_m_addr_type; 1704 bd_addr_slave[0] = setup->sm_s_addr_type; 1705 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1706 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1707 uint8_t iocap_a[3]; 1708 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1709 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1710 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1711 uint8_t iocap_b[3]; 1712 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1713 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1714 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1715 if (IS_RESPONDER(sm_conn->sm_role)){ 1716 // responder 1717 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1718 } else { 1719 // initiator 1720 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1721 } 1722 } 1723 1724 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1725 // validate E = f6() 1726 sm_key56_t bd_addr_master, bd_addr_slave; 1727 bd_addr_master[0] = setup->sm_m_addr_type; 1728 bd_addr_slave[0] = setup->sm_s_addr_type; 1729 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1730 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1731 1732 uint8_t iocap_a[3]; 1733 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1734 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1735 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1736 uint8_t iocap_b[3]; 1737 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1738 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1739 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1740 if (IS_RESPONDER(sm_conn->sm_role)){ 1741 // responder 1742 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1743 } else { 1744 // initiator 1745 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1746 } 1747 } 1748 1749 1750 // 1751 // Link Key Conversion Function h6 1752 // 1753 // h6(W, keyID) = AES-CMACW(keyID) 1754 // - W is 128 bits 1755 // - keyID is 32 bits 1756 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1757 const uint16_t message_len = 4; 1758 sm_cmac_connection = sm_conn; 1759 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1760 log_info("h6 key"); 1761 log_info_hexdump(w, 16); 1762 log_info("h6 message"); 1763 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1764 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1765 } 1766 1767 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1768 // Errata Service Release to the Bluetooth Specification: ESR09 1769 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1770 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1771 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1772 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1773 } 1774 1775 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1776 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1777 } 1778 1779 #endif 1780 1781 // key management legacy connections: 1782 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1783 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1784 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1785 // - responder reconnects: responder uses LTK receveived from master 1786 1787 // key management secure connections: 1788 // - both devices store same LTK from ECDH key exchange. 1789 1790 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1791 static void sm_load_security_info(sm_connection_t * sm_connection){ 1792 int encryption_key_size; 1793 int authenticated; 1794 int authorized; 1795 1796 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1797 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1798 &encryption_key_size, &authenticated, &authorized); 1799 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1800 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1801 sm_connection->sm_connection_authenticated = authenticated; 1802 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1803 } 1804 #endif 1805 1806 #ifdef ENABLE_LE_PERIPHERAL 1807 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1808 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1809 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1810 // re-establish used key encryption size 1811 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1812 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1813 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1814 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1815 log_info("sm: received ltk request with key size %u, authenticated %u", 1816 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1817 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1818 } 1819 #endif 1820 1821 static void sm_run(void){ 1822 1823 btstack_linked_list_iterator_t it; 1824 1825 // assert that we can send at least commands 1826 if (!hci_can_send_command_packet_now()) return; 1827 1828 // 1829 // non-connection related behaviour 1830 // 1831 1832 // distributed key generation 1833 switch (dkg_state){ 1834 case DKG_CALC_IRK: 1835 // already busy? 1836 if (sm_aes128_state == SM_AES128_IDLE) { 1837 // IRK = d1(IR, 1, 0) 1838 sm_key_t d1_prime; 1839 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1840 dkg_next_state(); 1841 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1842 return; 1843 } 1844 break; 1845 case DKG_CALC_DHK: 1846 // already busy? 1847 if (sm_aes128_state == SM_AES128_IDLE) { 1848 // DHK = d1(IR, 3, 0) 1849 sm_key_t d1_prime; 1850 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1851 dkg_next_state(); 1852 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1853 return; 1854 } 1855 break; 1856 default: 1857 break; 1858 } 1859 1860 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1861 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1862 #ifdef USE_MBEDTLS_FOR_ECDH 1863 sm_random_start(NULL); 1864 #else 1865 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1866 hci_send_cmd(&hci_le_read_local_p256_public_key); 1867 #endif 1868 return; 1869 } 1870 #endif 1871 1872 // random address updates 1873 switch (rau_state){ 1874 case RAU_GET_RANDOM: 1875 rau_next_state(); 1876 sm_random_start(NULL); 1877 return; 1878 case RAU_GET_ENC: 1879 // already busy? 1880 if (sm_aes128_state == SM_AES128_IDLE) { 1881 sm_key_t r_prime; 1882 sm_ah_r_prime(sm_random_address, r_prime); 1883 rau_next_state(); 1884 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1885 return; 1886 } 1887 break; 1888 case RAU_SET_ADDRESS: 1889 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1890 rau_state = RAU_IDLE; 1891 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1892 return; 1893 default: 1894 break; 1895 } 1896 1897 #ifdef ENABLE_CMAC_ENGINE 1898 // CMAC 1899 switch (sm_cmac_state){ 1900 case CMAC_CALC_SUBKEYS: 1901 case CMAC_CALC_MI: 1902 case CMAC_CALC_MLAST: 1903 // already busy? 1904 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1905 sm_cmac_handle_aes_engine_ready(); 1906 return; 1907 default: 1908 break; 1909 } 1910 #endif 1911 1912 // CSRK Lookup 1913 // -- if csrk lookup ready, find connection that require csrk lookup 1914 if (sm_address_resolution_idle()){ 1915 hci_connections_get_iterator(&it); 1916 while(btstack_linked_list_iterator_has_next(&it)){ 1917 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1918 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1919 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1920 // and start lookup 1921 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); 1922 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1923 break; 1924 } 1925 } 1926 } 1927 1928 // -- if csrk lookup ready, resolved addresses for received addresses 1929 if (sm_address_resolution_idle()) { 1930 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1931 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1932 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1933 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1934 btstack_memory_sm_lookup_entry_free(entry); 1935 } 1936 } 1937 1938 // -- Continue with CSRK device lookup by public or resolvable private address 1939 if (!sm_address_resolution_idle()){ 1940 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1941 while (sm_address_resolution_test < le_device_db_count()){ 1942 int addr_type; 1943 bd_addr_t addr; 1944 sm_key_t irk; 1945 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1946 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1947 1948 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1949 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1950 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1951 break; 1952 } 1953 1954 if (sm_address_resolution_addr_type == 0){ 1955 sm_address_resolution_test++; 1956 continue; 1957 } 1958 1959 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1960 1961 log_info("LE Device Lookup: calculate AH"); 1962 log_info_key("IRK", irk); 1963 1964 sm_key_t r_prime; 1965 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1966 sm_address_resolution_ah_calculation_active = 1; 1967 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1968 return; 1969 } 1970 1971 if (sm_address_resolution_test >= le_device_db_count()){ 1972 log_info("LE Device Lookup: not found"); 1973 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1974 } 1975 } 1976 1977 // handle basic actions that don't requires the full context 1978 hci_connections_get_iterator(&it); 1979 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1980 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1981 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1982 switch(sm_connection->sm_engine_state){ 1983 // responder side 1984 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1985 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1986 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1987 return; 1988 1989 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1990 case SM_SC_RECEIVED_LTK_REQUEST: 1991 switch (sm_connection->sm_irk_lookup_state){ 1992 case IRK_LOOKUP_FAILED: 1993 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1994 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1995 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1996 return; 1997 default: 1998 break; 1999 } 2000 break; 2001 #endif 2002 default: 2003 break; 2004 } 2005 } 2006 2007 // 2008 // active connection handling 2009 // -- use loop to handle next connection if lock on setup context is released 2010 2011 while (1) { 2012 2013 // Find connections that requires setup context and make active if no other is locked 2014 hci_connections_get_iterator(&it); 2015 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 2016 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2017 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2018 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2019 int done = 1; 2020 int err; 2021 UNUSED(err); 2022 switch (sm_connection->sm_engine_state) { 2023 #ifdef ENABLE_LE_PERIPHERAL 2024 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2025 // send packet if possible, 2026 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2027 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2028 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2029 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2030 } else { 2031 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2032 } 2033 // don't lock sxetup context yet 2034 done = 0; 2035 break; 2036 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2037 sm_reset_setup(); 2038 sm_init_setup(sm_connection); 2039 // recover pairing request 2040 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2041 err = sm_stk_generation_init(sm_connection); 2042 if (err){ 2043 setup->sm_pairing_failed_reason = err; 2044 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2045 break; 2046 } 2047 sm_timeout_start(sm_connection); 2048 // generate random number first, if we need to show passkey 2049 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2050 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2051 break; 2052 } 2053 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2054 break; 2055 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2056 sm_reset_setup(); 2057 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2058 break; 2059 #endif 2060 #ifdef ENABLE_LE_CENTRAL 2061 case SM_INITIATOR_PH0_HAS_LTK: 2062 sm_reset_setup(); 2063 sm_load_security_info(sm_connection); 2064 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2065 break; 2066 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2067 sm_reset_setup(); 2068 sm_init_setup(sm_connection); 2069 sm_timeout_start(sm_connection); 2070 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2071 break; 2072 #endif 2073 2074 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2075 case SM_SC_RECEIVED_LTK_REQUEST: 2076 switch (sm_connection->sm_irk_lookup_state){ 2077 case IRK_LOOKUP_SUCCEEDED: 2078 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2079 // start using context by loading security info 2080 sm_reset_setup(); 2081 sm_load_security_info(sm_connection); 2082 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2083 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2084 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2085 break; 2086 } 2087 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2088 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2089 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2090 // don't lock setup context yet 2091 return; 2092 default: 2093 // just wait until IRK lookup is completed 2094 // don't lock setup context yet 2095 done = 0; 2096 break; 2097 } 2098 break; 2099 #endif 2100 default: 2101 done = 0; 2102 break; 2103 } 2104 if (done){ 2105 sm_active_connection = sm_connection->sm_handle; 2106 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2107 } 2108 } 2109 2110 // 2111 // active connection handling 2112 // 2113 2114 if (sm_active_connection == 0) return; 2115 2116 // assert that we could send a SM PDU - not needed for all of the following 2117 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2118 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2119 return; 2120 } 2121 2122 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2123 if (!connection) return; 2124 2125 // send keypress notifications 2126 if (setup->sm_keypress_notification != 0xff){ 2127 uint8_t buffer[2]; 2128 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2129 buffer[1] = setup->sm_keypress_notification; 2130 setup->sm_keypress_notification = 0xff; 2131 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2132 return; 2133 } 2134 2135 sm_key_t plaintext; 2136 int key_distribution_flags; 2137 UNUSED(key_distribution_flags); 2138 2139 log_info("sm_run: state %u", connection->sm_engine_state); 2140 2141 switch (connection->sm_engine_state){ 2142 2143 // general 2144 case SM_GENERAL_SEND_PAIRING_FAILED: { 2145 uint8_t buffer[2]; 2146 buffer[0] = SM_CODE_PAIRING_FAILED; 2147 buffer[1] = setup->sm_pairing_failed_reason; 2148 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2149 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2150 sm_done_for_handle(connection->sm_handle); 2151 break; 2152 } 2153 2154 // responding state 2155 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2156 case SM_SC_W2_GET_RANDOM_A: 2157 sm_random_start(connection); 2158 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2159 break; 2160 case SM_SC_W2_GET_RANDOM_B: 2161 sm_random_start(connection); 2162 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2163 break; 2164 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2165 if (!sm_cmac_ready()) break; 2166 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2167 sm_sc_calculate_local_confirm(connection); 2168 break; 2169 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2170 if (!sm_cmac_ready()) break; 2171 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2172 sm_sc_calculate_remote_confirm(connection); 2173 break; 2174 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2175 if (!sm_cmac_ready()) break; 2176 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2177 sm_sc_calculate_f6_for_dhkey_check(connection); 2178 break; 2179 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2180 if (!sm_cmac_ready()) break; 2181 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2182 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2183 break; 2184 case SM_SC_W2_CALCULATE_F5_SALT: 2185 if (!sm_cmac_ready()) break; 2186 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2187 f5_calculate_salt(connection); 2188 break; 2189 case SM_SC_W2_CALCULATE_F5_MACKEY: 2190 if (!sm_cmac_ready()) break; 2191 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2192 f5_calculate_mackey(connection); 2193 break; 2194 case SM_SC_W2_CALCULATE_F5_LTK: 2195 if (!sm_cmac_ready()) break; 2196 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2197 f5_calculate_ltk(connection); 2198 break; 2199 case SM_SC_W2_CALCULATE_G2: 2200 if (!sm_cmac_ready()) break; 2201 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2202 g2_calculate(connection); 2203 break; 2204 case SM_SC_W2_CALCULATE_H6_ILK: 2205 if (!sm_cmac_ready()) break; 2206 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2207 h6_calculate_ilk(connection); 2208 break; 2209 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2210 if (!sm_cmac_ready()) break; 2211 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2212 h6_calculate_br_edr_link_key(connection); 2213 break; 2214 #endif 2215 2216 #ifdef ENABLE_LE_CENTRAL 2217 // initiator side 2218 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2219 sm_key_t peer_ltk_flipped; 2220 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2221 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2222 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2223 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2224 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2225 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2226 return; 2227 } 2228 2229 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2230 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2231 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2232 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2233 sm_timeout_reset(connection); 2234 break; 2235 #endif 2236 2237 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2238 2239 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2240 uint8_t buffer[65]; 2241 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2242 // 2243 reverse_256(ec_qx, &buffer[1]); 2244 reverse_256(ec_qy, &buffer[33]); 2245 2246 // stk generation method 2247 // passkey entry: notify app to show passkey or to request passkey 2248 switch (setup->sm_stk_generation_method){ 2249 case JUST_WORKS: 2250 case NK_BOTH_INPUT: 2251 if (IS_RESPONDER(connection->sm_role)){ 2252 // responder 2253 sm_sc_start_calculating_local_confirm(connection); 2254 } else { 2255 // initiator 2256 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2257 } 2258 break; 2259 case PK_INIT_INPUT: 2260 case PK_RESP_INPUT: 2261 case OK_BOTH_INPUT: 2262 // use random TK for display 2263 memcpy(setup->sm_ra, setup->sm_tk, 16); 2264 memcpy(setup->sm_rb, setup->sm_tk, 16); 2265 setup->sm_passkey_bit = 0; 2266 2267 if (IS_RESPONDER(connection->sm_role)){ 2268 // responder 2269 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2270 } else { 2271 // initiator 2272 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2273 } 2274 sm_trigger_user_response(connection); 2275 break; 2276 case OOB: 2277 // TODO: implement SC OOB 2278 break; 2279 } 2280 2281 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2282 sm_timeout_reset(connection); 2283 break; 2284 } 2285 case SM_SC_SEND_CONFIRMATION: { 2286 uint8_t buffer[17]; 2287 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2288 reverse_128(setup->sm_local_confirm, &buffer[1]); 2289 if (IS_RESPONDER(connection->sm_role)){ 2290 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2291 } else { 2292 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2293 } 2294 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2295 sm_timeout_reset(connection); 2296 break; 2297 } 2298 case SM_SC_SEND_PAIRING_RANDOM: { 2299 uint8_t buffer[17]; 2300 buffer[0] = SM_CODE_PAIRING_RANDOM; 2301 reverse_128(setup->sm_local_nonce, &buffer[1]); 2302 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2303 if (IS_RESPONDER(connection->sm_role)){ 2304 // responder 2305 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2306 } else { 2307 // initiator 2308 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2309 } 2310 } else { 2311 if (IS_RESPONDER(connection->sm_role)){ 2312 // responder 2313 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2314 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2315 } else { 2316 sm_sc_prepare_dhkey_check(connection); 2317 } 2318 } else { 2319 // initiator 2320 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2321 } 2322 } 2323 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2324 sm_timeout_reset(connection); 2325 break; 2326 } 2327 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2328 uint8_t buffer[17]; 2329 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2330 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2331 2332 if (IS_RESPONDER(connection->sm_role)){ 2333 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2334 } else { 2335 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2336 } 2337 2338 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2339 sm_timeout_reset(connection); 2340 break; 2341 } 2342 2343 #endif 2344 2345 #ifdef ENABLE_LE_PERIPHERAL 2346 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2347 // echo initiator for now 2348 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2349 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2350 2351 if (setup->sm_use_secure_connections){ 2352 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2353 // skip LTK/EDIV for SC 2354 log_info("sm: dropping encryption information flag"); 2355 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2356 } else { 2357 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2358 } 2359 2360 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); 2361 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); 2362 // update key distribution after ENC was dropped 2363 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2364 2365 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2366 sm_timeout_reset(connection); 2367 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2368 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2369 sm_trigger_user_response(connection); 2370 } 2371 return; 2372 #endif 2373 2374 case SM_PH2_SEND_PAIRING_RANDOM: { 2375 uint8_t buffer[17]; 2376 buffer[0] = SM_CODE_PAIRING_RANDOM; 2377 reverse_128(setup->sm_local_random, &buffer[1]); 2378 if (IS_RESPONDER(connection->sm_role)){ 2379 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2380 } else { 2381 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2382 } 2383 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2384 sm_timeout_reset(connection); 2385 break; 2386 } 2387 2388 case SM_PH2_GET_RANDOM_TK: 2389 case SM_PH2_C1_GET_RANDOM_A: 2390 case SM_PH2_C1_GET_RANDOM_B: 2391 case SM_PH3_GET_RANDOM: 2392 case SM_PH3_GET_DIV: 2393 sm_next_responding_state(connection); 2394 sm_random_start(connection); 2395 return; 2396 2397 case SM_PH2_C1_GET_ENC_B: 2398 case SM_PH2_C1_GET_ENC_D: 2399 // already busy? 2400 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2401 sm_next_responding_state(connection); 2402 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2403 return; 2404 2405 case SM_PH3_LTK_GET_ENC: 2406 case SM_RESPONDER_PH4_LTK_GET_ENC: 2407 // already busy? 2408 if (sm_aes128_state == SM_AES128_IDLE) { 2409 sm_key_t d_prime; 2410 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2411 sm_next_responding_state(connection); 2412 sm_aes128_start(sm_persistent_er, d_prime, connection); 2413 return; 2414 } 2415 break; 2416 2417 case SM_PH3_CSRK_GET_ENC: 2418 // already busy? 2419 if (sm_aes128_state == SM_AES128_IDLE) { 2420 sm_key_t d_prime; 2421 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2422 sm_next_responding_state(connection); 2423 sm_aes128_start(sm_persistent_er, d_prime, connection); 2424 return; 2425 } 2426 break; 2427 2428 case SM_PH2_C1_GET_ENC_C: 2429 // already busy? 2430 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2431 // calculate m_confirm using aes128 engine - step 1 2432 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); 2433 sm_next_responding_state(connection); 2434 sm_aes128_start(setup->sm_tk, plaintext, connection); 2435 break; 2436 case SM_PH2_C1_GET_ENC_A: 2437 // already busy? 2438 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2439 // calculate confirm using aes128 engine - step 1 2440 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); 2441 sm_next_responding_state(connection); 2442 sm_aes128_start(setup->sm_tk, plaintext, connection); 2443 break; 2444 case SM_PH2_CALC_STK: 2445 // already busy? 2446 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2447 // calculate STK 2448 if (IS_RESPONDER(connection->sm_role)){ 2449 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2450 } else { 2451 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2452 } 2453 sm_next_responding_state(connection); 2454 sm_aes128_start(setup->sm_tk, plaintext, connection); 2455 break; 2456 case SM_PH3_Y_GET_ENC: 2457 // already busy? 2458 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2459 // PH3B2 - calculate Y from - enc 2460 // Y = dm(DHK, Rand) 2461 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2462 sm_next_responding_state(connection); 2463 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2464 return; 2465 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2466 uint8_t buffer[17]; 2467 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2468 reverse_128(setup->sm_local_confirm, &buffer[1]); 2469 if (IS_RESPONDER(connection->sm_role)){ 2470 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2471 } else { 2472 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2473 } 2474 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2475 sm_timeout_reset(connection); 2476 return; 2477 } 2478 #ifdef ENABLE_LE_PERIPHERAL 2479 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2480 sm_key_t stk_flipped; 2481 reverse_128(setup->sm_ltk, stk_flipped); 2482 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2483 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2484 return; 2485 } 2486 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2487 sm_key_t ltk_flipped; 2488 reverse_128(setup->sm_ltk, ltk_flipped); 2489 connection->sm_engine_state = SM_RESPONDER_IDLE; 2490 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2491 return; 2492 } 2493 case SM_RESPONDER_PH4_Y_GET_ENC: 2494 // already busy? 2495 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2496 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2497 // Y = dm(DHK, Rand) 2498 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2499 sm_next_responding_state(connection); 2500 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2501 return; 2502 #endif 2503 #ifdef ENABLE_LE_CENTRAL 2504 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2505 sm_key_t stk_flipped; 2506 reverse_128(setup->sm_ltk, stk_flipped); 2507 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2508 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2509 return; 2510 } 2511 #endif 2512 2513 case SM_PH3_DISTRIBUTE_KEYS: 2514 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2515 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2516 uint8_t buffer[17]; 2517 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2518 reverse_128(setup->sm_ltk, &buffer[1]); 2519 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2520 sm_timeout_reset(connection); 2521 return; 2522 } 2523 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2524 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2525 uint8_t buffer[11]; 2526 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2527 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2528 reverse_64(setup->sm_local_rand, &buffer[3]); 2529 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2530 sm_timeout_reset(connection); 2531 return; 2532 } 2533 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2534 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2535 uint8_t buffer[17]; 2536 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2537 reverse_128(sm_persistent_irk, &buffer[1]); 2538 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2539 sm_timeout_reset(connection); 2540 return; 2541 } 2542 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2543 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2544 bd_addr_t local_address; 2545 uint8_t buffer[8]; 2546 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2547 gap_le_get_own_address(&buffer[1], local_address); 2548 reverse_bd_addr(local_address, &buffer[2]); 2549 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2550 sm_timeout_reset(connection); 2551 return; 2552 } 2553 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2554 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2555 2556 // hack to reproduce test runs 2557 if (test_use_fixed_local_csrk){ 2558 memset(setup->sm_local_csrk, 0xcc, 16); 2559 } 2560 2561 uint8_t buffer[17]; 2562 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2563 reverse_128(setup->sm_local_csrk, &buffer[1]); 2564 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2565 sm_timeout_reset(connection); 2566 return; 2567 } 2568 2569 // keys are sent 2570 if (IS_RESPONDER(connection->sm_role)){ 2571 // slave -> receive master keys if any 2572 if (sm_key_distribution_all_received(connection)){ 2573 sm_key_distribution_handle_all_received(connection); 2574 connection->sm_engine_state = SM_RESPONDER_IDLE; 2575 sm_done_for_handle(connection->sm_handle); 2576 } else { 2577 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2578 } 2579 } else { 2580 // master -> all done 2581 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2582 sm_done_for_handle(connection->sm_handle); 2583 } 2584 break; 2585 2586 default: 2587 break; 2588 } 2589 2590 // check again if active connection was released 2591 if (sm_active_connection) break; 2592 } 2593 } 2594 2595 // note: aes engine is ready as we just got the aes result 2596 static void sm_handle_encryption_result(uint8_t * data){ 2597 2598 sm_aes128_state = SM_AES128_IDLE; 2599 2600 if (sm_address_resolution_ah_calculation_active){ 2601 sm_address_resolution_ah_calculation_active = 0; 2602 // compare calulated address against connecting device 2603 uint8_t hash[3]; 2604 reverse_24(data, hash); 2605 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2606 log_info("LE Device Lookup: matched resolvable private address"); 2607 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2608 return; 2609 } 2610 // no match, try next 2611 sm_address_resolution_test++; 2612 return; 2613 } 2614 2615 switch (dkg_state){ 2616 case DKG_W4_IRK: 2617 reverse_128(data, sm_persistent_irk); 2618 log_info_key("irk", sm_persistent_irk); 2619 dkg_next_state(); 2620 return; 2621 case DKG_W4_DHK: 2622 reverse_128(data, sm_persistent_dhk); 2623 log_info_key("dhk", sm_persistent_dhk); 2624 dkg_next_state(); 2625 // SM Init Finished 2626 return; 2627 default: 2628 break; 2629 } 2630 2631 switch (rau_state){ 2632 case RAU_W4_ENC: 2633 reverse_24(data, &sm_random_address[3]); 2634 rau_next_state(); 2635 return; 2636 default: 2637 break; 2638 } 2639 2640 #ifdef ENABLE_CMAC_ENGINE 2641 switch (sm_cmac_state){ 2642 case CMAC_W4_SUBKEYS: 2643 case CMAC_W4_MI: 2644 case CMAC_W4_MLAST: 2645 { 2646 sm_key_t t; 2647 reverse_128(data, t); 2648 sm_cmac_handle_encryption_result(t); 2649 } 2650 return; 2651 default: 2652 break; 2653 } 2654 #endif 2655 2656 // retrieve sm_connection provided to sm_aes128_start_encryption 2657 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2658 if (!connection) return; 2659 switch (connection->sm_engine_state){ 2660 case SM_PH2_C1_W4_ENC_A: 2661 case SM_PH2_C1_W4_ENC_C: 2662 { 2663 sm_key_t t2; 2664 reverse_128(data, t2); 2665 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2666 } 2667 sm_next_responding_state(connection); 2668 return; 2669 case SM_PH2_C1_W4_ENC_B: 2670 reverse_128(data, setup->sm_local_confirm); 2671 log_info_key("c1!", setup->sm_local_confirm); 2672 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2673 return; 2674 case SM_PH2_C1_W4_ENC_D: 2675 { 2676 sm_key_t peer_confirm_test; 2677 reverse_128(data, peer_confirm_test); 2678 log_info_key("c1!", peer_confirm_test); 2679 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2680 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2681 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2682 return; 2683 } 2684 if (IS_RESPONDER(connection->sm_role)){ 2685 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2686 } else { 2687 connection->sm_engine_state = SM_PH2_CALC_STK; 2688 } 2689 } 2690 return; 2691 case SM_PH2_W4_STK: 2692 reverse_128(data, setup->sm_ltk); 2693 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2694 log_info_key("stk", setup->sm_ltk); 2695 if (IS_RESPONDER(connection->sm_role)){ 2696 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2697 } else { 2698 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2699 } 2700 return; 2701 case SM_PH3_Y_W4_ENC:{ 2702 sm_key_t y128; 2703 reverse_128(data, y128); 2704 setup->sm_local_y = big_endian_read_16(y128, 14); 2705 log_info_hex16("y", setup->sm_local_y); 2706 // PH3B3 - calculate EDIV 2707 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2708 log_info_hex16("ediv", setup->sm_local_ediv); 2709 // PH3B4 - calculate LTK - enc 2710 // LTK = d1(ER, DIV, 0)) 2711 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2712 return; 2713 } 2714 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2715 sm_key_t y128; 2716 reverse_128(data, y128); 2717 setup->sm_local_y = big_endian_read_16(y128, 14); 2718 log_info_hex16("y", setup->sm_local_y); 2719 2720 // PH3B3 - calculate DIV 2721 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2722 log_info_hex16("ediv", setup->sm_local_ediv); 2723 // PH3B4 - calculate LTK - enc 2724 // LTK = d1(ER, DIV, 0)) 2725 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2726 return; 2727 } 2728 case SM_PH3_LTK_W4_ENC: 2729 reverse_128(data, setup->sm_ltk); 2730 log_info_key("ltk", setup->sm_ltk); 2731 // calc CSRK next 2732 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2733 return; 2734 case SM_PH3_CSRK_W4_ENC: 2735 reverse_128(data, setup->sm_local_csrk); 2736 log_info_key("csrk", setup->sm_local_csrk); 2737 if (setup->sm_key_distribution_send_set){ 2738 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2739 } else { 2740 // no keys to send, just continue 2741 if (IS_RESPONDER(connection->sm_role)){ 2742 // slave -> receive master keys 2743 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2744 } else { 2745 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2746 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2747 } else { 2748 // master -> all done 2749 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2750 sm_done_for_handle(connection->sm_handle); 2751 } 2752 } 2753 } 2754 return; 2755 #ifdef ENABLE_LE_PERIPHERAL 2756 case SM_RESPONDER_PH4_LTK_W4_ENC: 2757 reverse_128(data, setup->sm_ltk); 2758 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2759 log_info_key("ltk", setup->sm_ltk); 2760 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2761 return; 2762 #endif 2763 default: 2764 break; 2765 } 2766 } 2767 2768 #ifdef USE_MBEDTLS_FOR_ECDH 2769 2770 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2771 UNUSED(context); 2772 2773 int offset = setup->sm_passkey_bit; 2774 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2775 while (size) { 2776 if (offset < 32){ 2777 *buffer++ = setup->sm_peer_qx[offset++]; 2778 } else { 2779 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2780 } 2781 size--; 2782 } 2783 setup->sm_passkey_bit = offset; 2784 return 0; 2785 } 2786 #endif 2787 2788 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2789 static void sm_handle_random_result(uint8_t * data){ 2790 2791 #ifdef USE_MBEDTLS_FOR_ECDH 2792 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2793 int num_bytes = setup->sm_passkey_bit; 2794 if (num_bytes < 32){ 2795 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2796 } else { 2797 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2798 } 2799 num_bytes += 8; 2800 setup->sm_passkey_bit = num_bytes; 2801 2802 if (num_bytes >= 64){ 2803 2804 // generate EC key 2805 setup->sm_passkey_bit = 0; 2806 mbedtls_mpi d; 2807 mbedtls_ecp_point P; 2808 mbedtls_mpi_init(&d); 2809 mbedtls_ecp_point_init(&P); 2810 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2811 log_info("gen keypair %x", res); 2812 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2813 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2814 mbedtls_mpi_write_binary(&d, ec_d, 32); 2815 mbedtls_ecp_point_free(&P); 2816 mbedtls_mpi_free(&d); 2817 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2818 log_info("Elliptic curve: d"); 2819 log_info_hexdump(ec_d,32); 2820 sm_log_ec_keypair(); 2821 2822 #if 0 2823 int i; 2824 sm_key256_t dhkey; 2825 for (i=0;i<10;i++){ 2826 // printf("test dhkey check\n"); 2827 memcpy(setup->sm_peer_qx, ec_qx, 32); 2828 memcpy(setup->sm_peer_qy, ec_qy, 32); 2829 sm_sc_calculate_dhkey(dhkey); 2830 // printf("test dhkey check end\n"); 2831 } 2832 #endif 2833 2834 } 2835 } 2836 #endif 2837 2838 switch (rau_state){ 2839 case RAU_W4_RANDOM: 2840 // non-resolvable vs. resolvable 2841 switch (gap_random_adress_type){ 2842 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2843 // resolvable: use random as prand and calc address hash 2844 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2845 memcpy(sm_random_address, data, 3); 2846 sm_random_address[0] &= 0x3f; 2847 sm_random_address[0] |= 0x40; 2848 rau_state = RAU_GET_ENC; 2849 break; 2850 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2851 default: 2852 // "The two most significant bits of the address shall be equal to ‘0’"" 2853 memcpy(sm_random_address, data, 6); 2854 sm_random_address[0] &= 0x3f; 2855 rau_state = RAU_SET_ADDRESS; 2856 break; 2857 } 2858 return; 2859 default: 2860 break; 2861 } 2862 2863 // retrieve sm_connection provided to sm_random_start 2864 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2865 if (!connection) return; 2866 switch (connection->sm_engine_state){ 2867 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2868 case SM_SC_W4_GET_RANDOM_A: 2869 memcpy(&setup->sm_local_nonce[0], data, 8); 2870 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2871 break; 2872 case SM_SC_W4_GET_RANDOM_B: 2873 memcpy(&setup->sm_local_nonce[8], data, 8); 2874 // initiator & jw/nc -> send pairing random 2875 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2876 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2877 break; 2878 } else { 2879 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2880 } 2881 break; 2882 #endif 2883 2884 case SM_PH2_W4_RANDOM_TK: 2885 { 2886 // map random to 0-999999 without speding much cycles on a modulus operation 2887 uint32_t tk = little_endian_read_32(data,0); 2888 tk = tk & 0xfffff; // 1048575 2889 if (tk >= 999999){ 2890 tk = tk - 999999; 2891 } 2892 sm_reset_tk(); 2893 big_endian_store_32(setup->sm_tk, 12, tk); 2894 if (IS_RESPONDER(connection->sm_role)){ 2895 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2896 } else { 2897 if (setup->sm_use_secure_connections){ 2898 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2899 } else { 2900 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2901 sm_trigger_user_response(connection); 2902 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2903 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2904 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2905 } 2906 } 2907 } 2908 return; 2909 } 2910 case SM_PH2_C1_W4_RANDOM_A: 2911 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2912 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2913 return; 2914 case SM_PH2_C1_W4_RANDOM_B: 2915 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2916 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2917 return; 2918 case SM_PH3_W4_RANDOM: 2919 reverse_64(data, setup->sm_local_rand); 2920 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2921 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2922 // no db for authenticated flag hack: store flag in bit 4 of LSB 2923 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2924 connection->sm_engine_state = SM_PH3_GET_DIV; 2925 return; 2926 case SM_PH3_W4_DIV: 2927 // use 16 bit from random value as div 2928 setup->sm_local_div = big_endian_read_16(data, 0); 2929 log_info_hex16("div", setup->sm_local_div); 2930 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2931 return; 2932 default: 2933 break; 2934 } 2935 } 2936 2937 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2938 2939 UNUSED(channel); 2940 UNUSED(size); 2941 2942 sm_connection_t * sm_conn; 2943 hci_con_handle_t con_handle; 2944 2945 switch (packet_type) { 2946 2947 case HCI_EVENT_PACKET: 2948 switch (hci_event_packet_get_type(packet)) { 2949 2950 case BTSTACK_EVENT_STATE: 2951 // bt stack activated, get started 2952 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2953 log_info("HCI Working!"); 2954 2955 // set local addr for le device db 2956 bd_addr_t local_bd_addr; 2957 gap_local_bd_addr(local_bd_addr); 2958 le_device_db_set_local_bd_addr(local_bd_addr); 2959 2960 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2961 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2962 if (!sm_have_ec_keypair){ 2963 setup->sm_passkey_bit = 0; 2964 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2965 } 2966 #endif 2967 // trigger Random Address generation if requested before 2968 switch (gap_random_adress_type){ 2969 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2970 rau_state = RAU_IDLE; 2971 break; 2972 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2973 rau_state = RAU_SET_ADDRESS; 2974 break; 2975 default: 2976 rau_state = RAU_GET_RANDOM; 2977 break; 2978 } 2979 sm_run(); 2980 } 2981 break; 2982 2983 case HCI_EVENT_LE_META: 2984 switch (packet[2]) { 2985 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2986 2987 log_info("sm: connected"); 2988 2989 if (packet[3]) return; // connection failed 2990 2991 con_handle = little_endian_read_16(packet, 4); 2992 sm_conn = sm_get_connection_for_handle(con_handle); 2993 if (!sm_conn) break; 2994 2995 sm_conn->sm_handle = con_handle; 2996 sm_conn->sm_role = packet[6]; 2997 sm_conn->sm_peer_addr_type = packet[7]; 2998 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 2999 3000 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3001 3002 // reset security properties 3003 sm_conn->sm_connection_encrypted = 0; 3004 sm_conn->sm_connection_authenticated = 0; 3005 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3006 sm_conn->sm_le_db_index = -1; 3007 3008 // prepare CSRK lookup (does not involve setup) 3009 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3010 3011 // just connected -> everything else happens in sm_run() 3012 if (IS_RESPONDER(sm_conn->sm_role)){ 3013 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3014 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3015 if (sm_slave_request_security) { 3016 // request security if requested by app 3017 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3018 } else { 3019 // otherwise, wait for pairing request 3020 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3021 } 3022 } 3023 break; 3024 } else { 3025 // master 3026 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3027 } 3028 break; 3029 3030 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3031 con_handle = little_endian_read_16(packet, 3); 3032 sm_conn = sm_get_connection_for_handle(con_handle); 3033 if (!sm_conn) break; 3034 3035 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3036 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3037 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3038 break; 3039 } 3040 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3041 // PH2 SEND LTK as we need to exchange keys in PH3 3042 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3043 break; 3044 } 3045 3046 // store rand and ediv 3047 reverse_64(&packet[5], sm_conn->sm_local_rand); 3048 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3049 3050 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3051 // potentially stored LTK is from the master 3052 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3053 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3054 break; 3055 } 3056 3057 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3058 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3059 #else 3060 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3061 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3062 #endif 3063 break; 3064 3065 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3066 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3067 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3068 log_error("Read Local P256 Public Key failed"); 3069 break; 3070 } 3071 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, ec_qx); 3072 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, ec_qy); 3073 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3074 sm_log_ec_keypair(); 3075 break; 3076 #endif 3077 default: 3078 break; 3079 } 3080 break; 3081 3082 case HCI_EVENT_ENCRYPTION_CHANGE: 3083 con_handle = little_endian_read_16(packet, 3); 3084 sm_conn = sm_get_connection_for_handle(con_handle); 3085 if (!sm_conn) break; 3086 3087 sm_conn->sm_connection_encrypted = packet[5]; 3088 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3089 sm_conn->sm_actual_encryption_key_size); 3090 log_info("event handler, state %u", sm_conn->sm_engine_state); 3091 if (!sm_conn->sm_connection_encrypted) break; 3092 // continue if part of initial pairing 3093 switch (sm_conn->sm_engine_state){ 3094 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3095 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3096 sm_done_for_handle(sm_conn->sm_handle); 3097 break; 3098 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3099 if (IS_RESPONDER(sm_conn->sm_role)){ 3100 // slave 3101 if (setup->sm_use_secure_connections){ 3102 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3103 } else { 3104 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3105 } 3106 } else { 3107 // master 3108 if (sm_key_distribution_all_received(sm_conn)){ 3109 // skip receiving keys as there are none 3110 sm_key_distribution_handle_all_received(sm_conn); 3111 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3112 } else { 3113 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3114 } 3115 } 3116 break; 3117 default: 3118 break; 3119 } 3120 break; 3121 3122 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3123 con_handle = little_endian_read_16(packet, 3); 3124 sm_conn = sm_get_connection_for_handle(con_handle); 3125 if (!sm_conn) break; 3126 3127 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3128 log_info("event handler, state %u", sm_conn->sm_engine_state); 3129 // continue if part of initial pairing 3130 switch (sm_conn->sm_engine_state){ 3131 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3132 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3133 sm_done_for_handle(sm_conn->sm_handle); 3134 break; 3135 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3136 if (IS_RESPONDER(sm_conn->sm_role)){ 3137 // slave 3138 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3139 } else { 3140 // master 3141 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3142 } 3143 break; 3144 default: 3145 break; 3146 } 3147 break; 3148 3149 3150 case HCI_EVENT_DISCONNECTION_COMPLETE: 3151 con_handle = little_endian_read_16(packet, 3); 3152 sm_done_for_handle(con_handle); 3153 sm_conn = sm_get_connection_for_handle(con_handle); 3154 if (!sm_conn) break; 3155 3156 // delete stored bonding on disconnect with authentication failure in ph0 3157 if (sm_conn->sm_role == 0 3158 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3159 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3160 le_device_db_remove(sm_conn->sm_le_db_index); 3161 } 3162 3163 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3164 sm_conn->sm_handle = 0; 3165 break; 3166 3167 case HCI_EVENT_COMMAND_COMPLETE: 3168 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3169 sm_handle_encryption_result(&packet[6]); 3170 break; 3171 } 3172 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3173 sm_handle_random_result(&packet[6]); 3174 break; 3175 } 3176 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3177 // Hack for Nordic nRF5 series that doesn't have public address: 3178 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3179 // - we use this as default for advertisements/connections 3180 if (hci_get_manufacturer() == COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3181 log_info("nRF5: using (fake) public address as random static address"); 3182 bd_addr_t addr; 3183 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3184 gap_random_address_set(addr); 3185 } 3186 } 3187 break; 3188 default: 3189 break; 3190 } 3191 break; 3192 default: 3193 break; 3194 } 3195 3196 sm_run(); 3197 } 3198 3199 static inline int sm_calc_actual_encryption_key_size(int other){ 3200 if (other < sm_min_encryption_key_size) return 0; 3201 if (other < sm_max_encryption_key_size) return other; 3202 return sm_max_encryption_key_size; 3203 } 3204 3205 3206 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3207 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3208 switch (method){ 3209 case JUST_WORKS: 3210 case NK_BOTH_INPUT: 3211 return 1; 3212 default: 3213 return 0; 3214 } 3215 } 3216 // responder 3217 3218 static int sm_passkey_used(stk_generation_method_t method){ 3219 switch (method){ 3220 case PK_RESP_INPUT: 3221 return 1; 3222 default: 3223 return 0; 3224 } 3225 } 3226 #endif 3227 3228 /** 3229 * @return ok 3230 */ 3231 static int sm_validate_stk_generation_method(void){ 3232 // check if STK generation method is acceptable by client 3233 switch (setup->sm_stk_generation_method){ 3234 case JUST_WORKS: 3235 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3236 case PK_RESP_INPUT: 3237 case PK_INIT_INPUT: 3238 case OK_BOTH_INPUT: 3239 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3240 case OOB: 3241 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3242 case NK_BOTH_INPUT: 3243 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3244 return 1; 3245 default: 3246 return 0; 3247 } 3248 } 3249 3250 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3251 3252 UNUSED(size); 3253 3254 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3255 sm_run(); 3256 } 3257 3258 if (packet_type != SM_DATA_PACKET) return; 3259 3260 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3261 if (!sm_conn) return; 3262 3263 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3264 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3265 return; 3266 } 3267 3268 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3269 3270 int err; 3271 UNUSED(err); 3272 3273 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3274 uint8_t buffer[5]; 3275 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3276 buffer[1] = 3; 3277 little_endian_store_16(buffer, 2, con_handle); 3278 buffer[4] = packet[1]; 3279 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3280 return; 3281 } 3282 3283 switch (sm_conn->sm_engine_state){ 3284 3285 // a sm timeout requries a new physical connection 3286 case SM_GENERAL_TIMEOUT: 3287 return; 3288 3289 #ifdef ENABLE_LE_CENTRAL 3290 3291 // Initiator 3292 case SM_INITIATOR_CONNECTED: 3293 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3294 sm_pdu_received_in_wrong_state(sm_conn); 3295 break; 3296 } 3297 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3298 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3299 break; 3300 } 3301 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3302 sm_key_t ltk; 3303 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3304 if (!sm_is_null_key(ltk)){ 3305 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3306 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3307 } else { 3308 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3309 } 3310 break; 3311 } 3312 // otherwise, store security request 3313 sm_conn->sm_security_request_received = 1; 3314 break; 3315 3316 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3317 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3318 sm_pdu_received_in_wrong_state(sm_conn); 3319 break; 3320 } 3321 // store pairing request 3322 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3323 err = sm_stk_generation_init(sm_conn); 3324 if (err){ 3325 setup->sm_pairing_failed_reason = err; 3326 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3327 break; 3328 } 3329 3330 // generate random number first, if we need to show passkey 3331 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3332 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3333 break; 3334 } 3335 3336 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3337 if (setup->sm_use_secure_connections){ 3338 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3339 if (setup->sm_stk_generation_method == JUST_WORKS){ 3340 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3341 sm_trigger_user_response(sm_conn); 3342 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3343 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3344 } 3345 } else { 3346 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3347 } 3348 break; 3349 } 3350 #endif 3351 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3352 sm_trigger_user_response(sm_conn); 3353 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3354 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3355 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3356 } 3357 break; 3358 3359 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3360 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3361 sm_pdu_received_in_wrong_state(sm_conn); 3362 break; 3363 } 3364 3365 // store s_confirm 3366 reverse_128(&packet[1], setup->sm_peer_confirm); 3367 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3368 break; 3369 3370 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3371 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3372 sm_pdu_received_in_wrong_state(sm_conn); 3373 break;; 3374 } 3375 3376 // received random value 3377 reverse_128(&packet[1], setup->sm_peer_random); 3378 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3379 break; 3380 #endif 3381 3382 #ifdef ENABLE_LE_PERIPHERAL 3383 // Responder 3384 case SM_RESPONDER_IDLE: 3385 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3386 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3387 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3388 sm_pdu_received_in_wrong_state(sm_conn); 3389 break;; 3390 } 3391 3392 // store pairing request 3393 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3394 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3395 break; 3396 #endif 3397 3398 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3399 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3400 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3401 sm_pdu_received_in_wrong_state(sm_conn); 3402 break; 3403 } 3404 3405 // store public key for DH Key calculation 3406 reverse_256(&packet[01], setup->sm_peer_qx); 3407 reverse_256(&packet[33], setup->sm_peer_qy); 3408 3409 #ifdef USE_MBEDTLS_FOR_ECDH 3410 // validate public key 3411 mbedtls_ecp_point Q; 3412 mbedtls_ecp_point_init( &Q ); 3413 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3414 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3415 mbedtls_mpi_lset(&Q.Z, 1); 3416 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3417 mbedtls_ecp_point_free( & Q); 3418 if (err){ 3419 log_error("sm: peer public key invalid %x", err); 3420 // uses "unspecified reason", there is no "public key invalid" error code 3421 sm_pdu_received_in_wrong_state(sm_conn); 3422 break; 3423 } 3424 3425 #endif 3426 if (IS_RESPONDER(sm_conn->sm_role)){ 3427 // responder 3428 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3429 } else { 3430 // initiator 3431 // stk generation method 3432 // passkey entry: notify app to show passkey or to request passkey 3433 switch (setup->sm_stk_generation_method){ 3434 case JUST_WORKS: 3435 case NK_BOTH_INPUT: 3436 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3437 break; 3438 case PK_RESP_INPUT: 3439 sm_sc_start_calculating_local_confirm(sm_conn); 3440 break; 3441 case PK_INIT_INPUT: 3442 case OK_BOTH_INPUT: 3443 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3444 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3445 break; 3446 } 3447 sm_sc_start_calculating_local_confirm(sm_conn); 3448 break; 3449 case OOB: 3450 // TODO: implement SC OOB 3451 break; 3452 } 3453 } 3454 break; 3455 3456 case SM_SC_W4_CONFIRMATION: 3457 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3458 sm_pdu_received_in_wrong_state(sm_conn); 3459 break; 3460 } 3461 // received confirm value 3462 reverse_128(&packet[1], setup->sm_peer_confirm); 3463 3464 if (IS_RESPONDER(sm_conn->sm_role)){ 3465 // responder 3466 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3467 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3468 // still waiting for passkey 3469 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3470 break; 3471 } 3472 } 3473 sm_sc_start_calculating_local_confirm(sm_conn); 3474 } else { 3475 // initiator 3476 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3477 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3478 } else { 3479 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3480 } 3481 } 3482 break; 3483 3484 case SM_SC_W4_PAIRING_RANDOM: 3485 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3486 sm_pdu_received_in_wrong_state(sm_conn); 3487 break; 3488 } 3489 3490 // received random value 3491 reverse_128(&packet[1], setup->sm_peer_nonce); 3492 3493 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3494 // only check for JUST WORK/NC in initiator role AND passkey entry 3495 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3496 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3497 } 3498 3499 sm_sc_state_after_receiving_random(sm_conn); 3500 break; 3501 3502 case SM_SC_W2_CALCULATE_G2: 3503 case SM_SC_W4_CALCULATE_G2: 3504 case SM_SC_W2_CALCULATE_F5_SALT: 3505 case SM_SC_W4_CALCULATE_F5_SALT: 3506 case SM_SC_W2_CALCULATE_F5_MACKEY: 3507 case SM_SC_W4_CALCULATE_F5_MACKEY: 3508 case SM_SC_W2_CALCULATE_F5_LTK: 3509 case SM_SC_W4_CALCULATE_F5_LTK: 3510 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3511 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3512 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3513 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3514 sm_pdu_received_in_wrong_state(sm_conn); 3515 break; 3516 } 3517 // store DHKey Check 3518 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3519 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3520 3521 // have we been only waiting for dhkey check command? 3522 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3523 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3524 } 3525 break; 3526 #endif 3527 3528 #ifdef ENABLE_LE_PERIPHERAL 3529 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3530 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3531 sm_pdu_received_in_wrong_state(sm_conn); 3532 break; 3533 } 3534 3535 // received confirm value 3536 reverse_128(&packet[1], setup->sm_peer_confirm); 3537 3538 // notify client to hide shown passkey 3539 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3540 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3541 } 3542 3543 // handle user cancel pairing? 3544 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3545 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3546 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3547 break; 3548 } 3549 3550 // wait for user action? 3551 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3552 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3553 break; 3554 } 3555 3556 // calculate and send local_confirm 3557 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3558 break; 3559 3560 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3561 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3562 sm_pdu_received_in_wrong_state(sm_conn); 3563 break;; 3564 } 3565 3566 // received random value 3567 reverse_128(&packet[1], setup->sm_peer_random); 3568 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3569 break; 3570 #endif 3571 3572 case SM_PH3_RECEIVE_KEYS: 3573 switch(packet[0]){ 3574 case SM_CODE_ENCRYPTION_INFORMATION: 3575 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3576 reverse_128(&packet[1], setup->sm_peer_ltk); 3577 break; 3578 3579 case SM_CODE_MASTER_IDENTIFICATION: 3580 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3581 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3582 reverse_64(&packet[3], setup->sm_peer_rand); 3583 break; 3584 3585 case SM_CODE_IDENTITY_INFORMATION: 3586 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3587 reverse_128(&packet[1], setup->sm_peer_irk); 3588 break; 3589 3590 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3591 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3592 setup->sm_peer_addr_type = packet[1]; 3593 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3594 break; 3595 3596 case SM_CODE_SIGNING_INFORMATION: 3597 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3598 reverse_128(&packet[1], setup->sm_peer_csrk); 3599 break; 3600 default: 3601 // Unexpected PDU 3602 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3603 break; 3604 } 3605 // done with key distribution? 3606 if (sm_key_distribution_all_received(sm_conn)){ 3607 3608 sm_key_distribution_handle_all_received(sm_conn); 3609 3610 if (IS_RESPONDER(sm_conn->sm_role)){ 3611 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3612 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3613 } else { 3614 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3615 sm_done_for_handle(sm_conn->sm_handle); 3616 } 3617 } else { 3618 if (setup->sm_use_secure_connections){ 3619 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3620 } else { 3621 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3622 } 3623 } 3624 } 3625 break; 3626 default: 3627 // Unexpected PDU 3628 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3629 break; 3630 } 3631 3632 // try to send preparared packet 3633 sm_run(); 3634 } 3635 3636 // Security Manager Client API 3637 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3638 sm_get_oob_data = get_oob_data_callback; 3639 } 3640 3641 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3642 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3643 } 3644 3645 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3646 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3647 } 3648 3649 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3650 sm_min_encryption_key_size = min_size; 3651 sm_max_encryption_key_size = max_size; 3652 } 3653 3654 void sm_set_authentication_requirements(uint8_t auth_req){ 3655 sm_auth_req = auth_req; 3656 } 3657 3658 void sm_set_io_capabilities(io_capability_t io_capability){ 3659 sm_io_capabilities = io_capability; 3660 } 3661 3662 #ifdef ENABLE_LE_PERIPHERAL 3663 void sm_set_request_security(int enable){ 3664 sm_slave_request_security = enable; 3665 } 3666 #endif 3667 3668 void sm_set_er(sm_key_t er){ 3669 memcpy(sm_persistent_er, er, 16); 3670 } 3671 3672 void sm_set_ir(sm_key_t ir){ 3673 memcpy(sm_persistent_ir, ir, 16); 3674 } 3675 3676 // Testing support only 3677 void sm_test_set_irk(sm_key_t irk){ 3678 memcpy(sm_persistent_irk, irk, 16); 3679 sm_persistent_irk_ready = 1; 3680 } 3681 3682 void sm_test_use_fixed_local_csrk(void){ 3683 test_use_fixed_local_csrk = 1; 3684 } 3685 3686 void sm_init(void){ 3687 // set some (BTstack default) ER and IR 3688 int i; 3689 sm_key_t er; 3690 sm_key_t ir; 3691 for (i=0;i<16;i++){ 3692 er[i] = 0x30 + i; 3693 ir[i] = 0x90 + i; 3694 } 3695 sm_set_er(er); 3696 sm_set_ir(ir); 3697 // defaults 3698 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3699 | SM_STK_GENERATION_METHOD_OOB 3700 | SM_STK_GENERATION_METHOD_PASSKEY 3701 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3702 3703 sm_max_encryption_key_size = 16; 3704 sm_min_encryption_key_size = 7; 3705 3706 #ifdef ENABLE_CMAC_ENGINE 3707 sm_cmac_state = CMAC_IDLE; 3708 #endif 3709 dkg_state = DKG_W4_WORKING; 3710 rau_state = RAU_W4_WORKING; 3711 sm_aes128_state = SM_AES128_IDLE; 3712 sm_address_resolution_test = -1; // no private address to resolve yet 3713 sm_address_resolution_ah_calculation_active = 0; 3714 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3715 sm_address_resolution_general_queue = NULL; 3716 3717 gap_random_adress_update_period = 15 * 60 * 1000L; 3718 sm_active_connection = 0; 3719 3720 test_use_fixed_local_csrk = 0; 3721 3722 // register for HCI Events from HCI 3723 hci_event_callback_registration.callback = &sm_event_packet_handler; 3724 hci_add_event_handler(&hci_event_callback_registration); 3725 3726 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3727 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3728 3729 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3730 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3731 #endif 3732 3733 #ifdef USE_MBEDTLS_FOR_ECDH 3734 3735 #ifndef HAVE_MALLOC 3736 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3737 #endif 3738 mbedtls_ecp_group_init(&mbedtls_ec_group); 3739 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3740 #if 0 3741 // test 3742 sm_test_use_fixed_ec_keypair(); 3743 if (sm_have_ec_keypair){ 3744 printf("test dhkey check\n"); 3745 sm_key256_t dhkey; 3746 memcpy(setup->sm_peer_qx, ec_qx, 32); 3747 memcpy(setup->sm_peer_qy, ec_qy, 32); 3748 sm_sc_calculate_dhkey(dhkey); 3749 } 3750 #endif 3751 #endif 3752 } 3753 3754 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3755 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3756 memcpy(ec_qx, qx, 32); 3757 memcpy(ec_qy, qy, 32); 3758 memcpy(ec_d, d, 32); 3759 sm_have_ec_keypair = 1; 3760 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3761 #else 3762 UNUSED(qx); 3763 UNUSED(qy); 3764 UNUSED(d); 3765 #endif 3766 } 3767 3768 void sm_test_use_fixed_ec_keypair(void){ 3769 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3770 #ifdef USE_MBEDTLS_FOR_ECDH 3771 // use test keypair from spec 3772 mbedtls_mpi x; 3773 mbedtls_mpi_init(&x); 3774 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3775 mbedtls_mpi_write_binary(&x, ec_d, 32); 3776 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3777 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3778 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3779 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3780 mbedtls_mpi_free(&x); 3781 #endif 3782 sm_have_ec_keypair = 1; 3783 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3784 #endif 3785 } 3786 3787 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3788 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3789 if (!hci_con) return NULL; 3790 return &hci_con->sm_connection; 3791 } 3792 3793 // @returns 0 if not encrypted, 7-16 otherwise 3794 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3795 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3796 if (!sm_conn) return 0; // wrong connection 3797 if (!sm_conn->sm_connection_encrypted) return 0; 3798 return sm_conn->sm_actual_encryption_key_size; 3799 } 3800 3801 int sm_authenticated(hci_con_handle_t con_handle){ 3802 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3803 if (!sm_conn) return 0; // wrong connection 3804 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3805 return sm_conn->sm_connection_authenticated; 3806 } 3807 3808 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3809 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3810 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3811 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3812 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3813 return sm_conn->sm_connection_authorization_state; 3814 } 3815 3816 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3817 switch (sm_conn->sm_engine_state){ 3818 case SM_GENERAL_IDLE: 3819 case SM_RESPONDER_IDLE: 3820 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3821 sm_run(); 3822 break; 3823 default: 3824 break; 3825 } 3826 } 3827 3828 /** 3829 * @brief Trigger Security Request 3830 */ 3831 void sm_send_security_request(hci_con_handle_t con_handle){ 3832 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3833 if (!sm_conn) return; 3834 sm_send_security_request_for_connection(sm_conn); 3835 } 3836 3837 // request pairing 3838 void sm_request_pairing(hci_con_handle_t con_handle){ 3839 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3840 if (!sm_conn) return; // wrong connection 3841 3842 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3843 if (IS_RESPONDER(sm_conn->sm_role)){ 3844 sm_send_security_request_for_connection(sm_conn); 3845 } else { 3846 // used as a trigger to start central/master/initiator security procedures 3847 uint16_t ediv; 3848 sm_key_t ltk; 3849 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3850 switch (sm_conn->sm_irk_lookup_state){ 3851 case IRK_LOOKUP_FAILED: 3852 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3853 break; 3854 case IRK_LOOKUP_SUCCEEDED: 3855 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3856 if (!sm_is_null_key(ltk) || ediv){ 3857 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3858 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3859 } else { 3860 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3861 } 3862 break; 3863 default: 3864 sm_conn->sm_bonding_requested = 1; 3865 break; 3866 } 3867 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3868 sm_conn->sm_bonding_requested = 1; 3869 } 3870 } 3871 sm_run(); 3872 } 3873 3874 // called by client app on authorization request 3875 void sm_authorization_decline(hci_con_handle_t con_handle){ 3876 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3877 if (!sm_conn) return; // wrong connection 3878 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3879 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3880 } 3881 3882 void sm_authorization_grant(hci_con_handle_t con_handle){ 3883 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3884 if (!sm_conn) return; // wrong connection 3885 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3886 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3887 } 3888 3889 // GAP Bonding API 3890 3891 void sm_bonding_decline(hci_con_handle_t con_handle){ 3892 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3893 if (!sm_conn) return; // wrong connection 3894 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3895 3896 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3897 switch (setup->sm_stk_generation_method){ 3898 case PK_RESP_INPUT: 3899 case PK_INIT_INPUT: 3900 case OK_BOTH_INPUT: 3901 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3902 break; 3903 case NK_BOTH_INPUT: 3904 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3905 break; 3906 case JUST_WORKS: 3907 case OOB: 3908 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3909 break; 3910 } 3911 } 3912 sm_run(); 3913 } 3914 3915 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3916 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3917 if (!sm_conn) return; // wrong connection 3918 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3919 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3920 if (setup->sm_use_secure_connections){ 3921 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3922 } else { 3923 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3924 } 3925 } 3926 3927 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3928 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3929 sm_sc_prepare_dhkey_check(sm_conn); 3930 } 3931 #endif 3932 3933 sm_run(); 3934 } 3935 3936 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3937 // for now, it's the same 3938 sm_just_works_confirm(con_handle); 3939 } 3940 3941 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3942 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3943 if (!sm_conn) return; // wrong connection 3944 sm_reset_tk(); 3945 big_endian_store_32(setup->sm_tk, 12, passkey); 3946 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3947 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3948 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3949 } 3950 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3951 memcpy(setup->sm_ra, setup->sm_tk, 16); 3952 memcpy(setup->sm_rb, setup->sm_tk, 16); 3953 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3954 sm_sc_start_calculating_local_confirm(sm_conn); 3955 } 3956 #endif 3957 sm_run(); 3958 } 3959 3960 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3961 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3962 if (!sm_conn) return; // wrong connection 3963 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3964 setup->sm_keypress_notification = action; 3965 sm_run(); 3966 } 3967 3968 /** 3969 * @brief Identify device in LE Device DB 3970 * @param handle 3971 * @returns index from le_device_db or -1 if not found/identified 3972 */ 3973 int sm_le_device_index(hci_con_handle_t con_handle ){ 3974 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3975 if (!sm_conn) return -1; 3976 return sm_conn->sm_le_db_index; 3977 } 3978 3979 static int gap_random_address_type_requires_updates(void){ 3980 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3981 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3982 return 1; 3983 } 3984 3985 static uint8_t own_address_type(void){ 3986 switch (gap_random_adress_type){ 3987 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3988 return BD_ADDR_TYPE_LE_PUBLIC; 3989 default: 3990 return BD_ADDR_TYPE_LE_RANDOM; 3991 } 3992 } 3993 3994 // GAP LE API 3995 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3996 gap_random_address_update_stop(); 3997 gap_random_adress_type = random_address_type; 3998 hci_le_set_own_address_type(own_address_type()); 3999 if (!gap_random_address_type_requires_updates()) return; 4000 gap_random_address_update_start(); 4001 gap_random_address_trigger(); 4002 } 4003 4004 gap_random_address_type_t gap_random_address_get_mode(void){ 4005 return gap_random_adress_type; 4006 } 4007 4008 void gap_random_address_set_update_period(int period_ms){ 4009 gap_random_adress_update_period = period_ms; 4010 if (!gap_random_address_type_requires_updates()) return; 4011 gap_random_address_update_stop(); 4012 gap_random_address_update_start(); 4013 } 4014 4015 void gap_random_address_set(bd_addr_t addr){ 4016 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4017 memcpy(sm_random_address, addr, 6); 4018 if (rau_state == RAU_W4_WORKING) return; 4019 rau_state = RAU_SET_ADDRESS; 4020 sm_run(); 4021 } 4022 4023 #ifdef ENABLE_LE_PERIPHERAL 4024 /* 4025 * @brief Set Advertisement Paramters 4026 * @param adv_int_min 4027 * @param adv_int_max 4028 * @param adv_type 4029 * @param direct_address_type 4030 * @param direct_address 4031 * @param channel_map 4032 * @param filter_policy 4033 * 4034 * @note own_address_type is used from gap_random_address_set_mode 4035 */ 4036 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4037 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4038 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4039 direct_address_typ, direct_address, channel_map, filter_policy); 4040 } 4041 #endif 4042 4043