1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <stdio.h> 41 #include <string.h> 42 #include <inttypes.h> 43 44 #include "ble/le_device_db.h" 45 #include "ble/core.h" 46 #include "ble/sm.h" 47 #include "bluetooth_company_id.h" 48 #include "btstack_debug.h" 49 #include "btstack_event.h" 50 #include "btstack_linked_list.h" 51 #include "btstack_memory.h" 52 #include "gap.h" 53 #include "hci.h" 54 #include "hci_dump.h" 55 #include "l2cap.h" 56 57 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 58 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 59 #endif 60 61 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 62 #define IS_RESPONDER(role) (role) 63 #else 64 #ifdef ENABLE_LE_CENTRAL 65 // only central - never responder (avoid 'unused variable' warnings) 66 #define IS_RESPONDER(role) (0 && role) 67 #else 68 // only peripheral - always responder (avoid 'unused variable' warnings) 69 #define IS_RESPONDER(role) (1 || role) 70 #endif 71 #endif 72 73 #ifdef ENABLE_LE_SECURE_CONNECTIONS 74 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 75 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 76 #else 77 // #define USE_MBEDTLS_FOR_ECDH 78 #define USE_MICROECC_FOR_ECDH 79 #endif 80 #endif 81 82 // Software ECDH implementation provided by mbedtls 83 #ifdef USE_MBEDTLS_FOR_ECDH 84 #include "mbedtls/config.h" 85 #include "mbedtls/platform.h" 86 #include "mbedtls/ecp.h" 87 #include "sm_mbedtls_allocator.h" 88 #endif 89 90 // Software ECDH implementation provided by micro-ecc 91 #ifdef USE_MICROECC_FOR_ECDH 92 #include "uECC.h" 93 #endif 94 95 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 96 #define ENABLE_CMAC_ENGINE 97 #endif 98 99 // 100 // SM internal types and globals 101 // 102 103 typedef enum { 104 DKG_W4_WORKING, 105 DKG_CALC_IRK, 106 DKG_W4_IRK, 107 DKG_CALC_DHK, 108 DKG_W4_DHK, 109 DKG_READY 110 } derived_key_generation_t; 111 112 typedef enum { 113 RAU_W4_WORKING, 114 RAU_IDLE, 115 RAU_GET_RANDOM, 116 RAU_W4_RANDOM, 117 RAU_GET_ENC, 118 RAU_W4_ENC, 119 RAU_SET_ADDRESS, 120 } random_address_update_t; 121 122 typedef enum { 123 CMAC_IDLE, 124 CMAC_CALC_SUBKEYS, 125 CMAC_W4_SUBKEYS, 126 CMAC_CALC_MI, 127 CMAC_W4_MI, 128 CMAC_CALC_MLAST, 129 CMAC_W4_MLAST 130 } cmac_state_t; 131 132 typedef enum { 133 JUST_WORKS, 134 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 135 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 136 OK_BOTH_INPUT, // Only input on both, both input PK 137 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 138 OOB // OOB available on both sides 139 } stk_generation_method_t; 140 141 typedef enum { 142 SM_USER_RESPONSE_IDLE, 143 SM_USER_RESPONSE_PENDING, 144 SM_USER_RESPONSE_CONFIRM, 145 SM_USER_RESPONSE_PASSKEY, 146 SM_USER_RESPONSE_DECLINE 147 } sm_user_response_t; 148 149 typedef enum { 150 SM_AES128_IDLE, 151 SM_AES128_ACTIVE 152 } sm_aes128_state_t; 153 154 typedef enum { 155 ADDRESS_RESOLUTION_IDLE, 156 ADDRESS_RESOLUTION_GENERAL, 157 ADDRESS_RESOLUTION_FOR_CONNECTION, 158 } address_resolution_mode_t; 159 160 typedef enum { 161 ADDRESS_RESOLUTION_SUCEEDED, 162 ADDRESS_RESOLUTION_FAILED, 163 } address_resolution_event_t; 164 165 typedef enum { 166 EC_KEY_GENERATION_IDLE, 167 EC_KEY_GENERATION_ACTIVE, 168 EC_KEY_GENERATION_W4_KEY, 169 EC_KEY_GENERATION_DONE, 170 } ec_key_generation_state_t; 171 172 typedef enum { 173 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 174 } sm_state_var_t; 175 176 // 177 // GLOBAL DATA 178 // 179 180 static uint8_t test_use_fixed_local_csrk; 181 182 // configuration 183 static uint8_t sm_accepted_stk_generation_methods; 184 static uint8_t sm_max_encryption_key_size; 185 static uint8_t sm_min_encryption_key_size; 186 static uint8_t sm_auth_req = 0; 187 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 188 static uint8_t sm_slave_request_security; 189 #ifdef ENABLE_LE_SECURE_CONNECTIONS 190 static uint8_t sm_have_ec_keypair; 191 #endif 192 193 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 194 static sm_key_t sm_persistent_er; 195 static sm_key_t sm_persistent_ir; 196 197 // derived from sm_persistent_ir 198 static sm_key_t sm_persistent_dhk; 199 static sm_key_t sm_persistent_irk; 200 static uint8_t sm_persistent_irk_ready = 0; // used for testing 201 static derived_key_generation_t dkg_state; 202 203 // derived from sm_persistent_er 204 // .. 205 206 // random address update 207 static random_address_update_t rau_state; 208 static bd_addr_t sm_random_address; 209 210 // CMAC Calculation: General 211 #ifdef ENABLE_CMAC_ENGINE 212 static cmac_state_t sm_cmac_state; 213 static uint16_t sm_cmac_message_len; 214 static sm_key_t sm_cmac_k; 215 static sm_key_t sm_cmac_x; 216 static sm_key_t sm_cmac_m_last; 217 static uint8_t sm_cmac_block_current; 218 static uint8_t sm_cmac_block_count; 219 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 220 static void (*sm_cmac_done_handler)(uint8_t * hash); 221 #endif 222 223 // CMAC for ATT Signed Writes 224 #ifdef ENABLE_LE_SIGNED_WRITE 225 static uint8_t sm_cmac_header[3]; 226 static const uint8_t * sm_cmac_message; 227 static uint8_t sm_cmac_sign_counter[4]; 228 #endif 229 230 // CMAC for Secure Connection functions 231 #ifdef ENABLE_LE_SECURE_CONNECTIONS 232 static sm_connection_t * sm_cmac_connection; 233 static uint8_t sm_cmac_sc_buffer[80]; 234 #endif 235 236 // resolvable private address lookup / CSRK calculation 237 static int sm_address_resolution_test; 238 static int sm_address_resolution_ah_calculation_active; 239 static uint8_t sm_address_resolution_addr_type; 240 static bd_addr_t sm_address_resolution_address; 241 static void * sm_address_resolution_context; 242 static address_resolution_mode_t sm_address_resolution_mode; 243 static btstack_linked_list_t sm_address_resolution_general_queue; 244 245 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 246 static sm_aes128_state_t sm_aes128_state; 247 static void * sm_aes128_context; 248 249 // random engine. store context (ususally sm_connection_t) 250 static void * sm_random_context; 251 252 // to receive hci events 253 static btstack_packet_callback_registration_t hci_event_callback_registration; 254 255 /* to dispatch sm event */ 256 static btstack_linked_list_t sm_event_handlers; 257 258 // LE Secure Connections 259 #ifdef ENABLE_LE_SECURE_CONNECTIONS 260 static ec_key_generation_state_t ec_key_generation_state; 261 static uint8_t ec_d[32]; 262 static uint8_t ec_q[64]; 263 #endif 264 265 // Software ECDH implementation provided by mbedtls 266 #ifdef USE_MBEDTLS_FOR_ECDH 267 // group is always valid 268 static mbedtls_ecp_group mbedtls_ec_group; 269 #ifndef HAVE_MALLOC 270 // COMP Method with Window 2 271 // 1300 bytes with 23 allocations 272 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 273 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 274 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 275 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 276 #endif 277 #endif 278 279 // 280 // Volume 3, Part H, Chapter 24 281 // "Security shall be initiated by the Security Manager in the device in the master role. 282 // The device in the slave role shall be the responding device." 283 // -> master := initiator, slave := responder 284 // 285 286 // data needed for security setup 287 typedef struct sm_setup_context { 288 289 btstack_timer_source_t sm_timeout; 290 291 // used in all phases 292 uint8_t sm_pairing_failed_reason; 293 294 // user response, (Phase 1 and/or 2) 295 uint8_t sm_user_response; 296 uint8_t sm_keypress_notification; 297 298 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 299 int sm_key_distribution_send_set; 300 int sm_key_distribution_received_set; 301 302 // Phase 2 (Pairing over SMP) 303 stk_generation_method_t sm_stk_generation_method; 304 sm_key_t sm_tk; 305 uint8_t sm_use_secure_connections; 306 307 sm_key_t sm_c1_t3_value; // c1 calculation 308 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 309 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 310 sm_key_t sm_local_random; 311 sm_key_t sm_local_confirm; 312 sm_key_t sm_peer_random; 313 sm_key_t sm_peer_confirm; 314 uint8_t sm_m_addr_type; // address and type can be removed 315 uint8_t sm_s_addr_type; // '' 316 bd_addr_t sm_m_address; // '' 317 bd_addr_t sm_s_address; // '' 318 sm_key_t sm_ltk; 319 320 uint8_t sm_state_vars; 321 #ifdef ENABLE_LE_SECURE_CONNECTIONS 322 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 323 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 324 sm_key_t sm_local_nonce; // might be combined with sm_local_random 325 sm_key_t sm_peer_dhkey_check; 326 sm_key_t sm_local_dhkey_check; 327 sm_key_t sm_ra; 328 sm_key_t sm_rb; 329 sm_key_t sm_t; // used for f5 and h6 330 sm_key_t sm_mackey; 331 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 332 #endif 333 334 // Phase 3 335 336 // key distribution, we generate 337 uint16_t sm_local_y; 338 uint16_t sm_local_div; 339 uint16_t sm_local_ediv; 340 uint8_t sm_local_rand[8]; 341 sm_key_t sm_local_ltk; 342 sm_key_t sm_local_csrk; 343 sm_key_t sm_local_irk; 344 // sm_local_address/addr_type not needed 345 346 // key distribution, received from peer 347 uint16_t sm_peer_y; 348 uint16_t sm_peer_div; 349 uint16_t sm_peer_ediv; 350 uint8_t sm_peer_rand[8]; 351 sm_key_t sm_peer_ltk; 352 sm_key_t sm_peer_irk; 353 sm_key_t sm_peer_csrk; 354 uint8_t sm_peer_addr_type; 355 bd_addr_t sm_peer_address; 356 357 } sm_setup_context_t; 358 359 // 360 static sm_setup_context_t the_setup; 361 static sm_setup_context_t * setup = &the_setup; 362 363 // active connection - the one for which the_setup is used for 364 static uint16_t sm_active_connection = 0; 365 366 // @returns 1 if oob data is available 367 // stores oob data in provided 16 byte buffer if not null 368 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 369 370 // horizontal: initiator capabilities 371 // vertial: responder capabilities 372 static const stk_generation_method_t stk_generation_method [5] [5] = { 373 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 374 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 375 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 376 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 377 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 378 }; 379 380 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 381 #ifdef ENABLE_LE_SECURE_CONNECTIONS 382 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 383 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 384 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 385 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 386 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 387 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 388 }; 389 #endif 390 391 static void sm_run(void); 392 static void sm_done_for_handle(hci_con_handle_t con_handle); 393 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 394 static inline int sm_calc_actual_encryption_key_size(int other); 395 static int sm_validate_stk_generation_method(void); 396 397 static void log_info_hex16(const char * name, uint16_t value){ 398 log_info("%-6s 0x%04x", name, value); 399 } 400 401 // @returns 1 if all bytes are 0 402 static int sm_is_null(uint8_t * data, int size){ 403 int i; 404 for (i=0; i < size ; i++){ 405 if (data[i]) return 0; 406 } 407 return 1; 408 } 409 410 static int sm_is_null_random(uint8_t random[8]){ 411 return sm_is_null(random, 8); 412 } 413 414 static int sm_is_null_key(uint8_t * key){ 415 return sm_is_null(key, 16); 416 } 417 418 // Key utils 419 static void sm_reset_tk(void){ 420 int i; 421 for (i=0;i<16;i++){ 422 setup->sm_tk[i] = 0; 423 } 424 } 425 426 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 427 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 428 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 429 int i; 430 for (i = max_encryption_size ; i < 16 ; i++){ 431 key[15-i] = 0; 432 } 433 } 434 435 // SMP Timeout implementation 436 437 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 438 // the Security Manager Timer shall be reset and started. 439 // 440 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 441 // 442 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 443 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 444 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 445 // established. 446 447 static void sm_timeout_handler(btstack_timer_source_t * timer){ 448 log_info("SM timeout"); 449 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 450 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 451 sm_done_for_handle(sm_conn->sm_handle); 452 453 // trigger handling of next ready connection 454 sm_run(); 455 } 456 static void sm_timeout_start(sm_connection_t * sm_conn){ 457 btstack_run_loop_remove_timer(&setup->sm_timeout); 458 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 459 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 460 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 461 btstack_run_loop_add_timer(&setup->sm_timeout); 462 } 463 static void sm_timeout_stop(void){ 464 btstack_run_loop_remove_timer(&setup->sm_timeout); 465 } 466 static void sm_timeout_reset(sm_connection_t * sm_conn){ 467 sm_timeout_stop(); 468 sm_timeout_start(sm_conn); 469 } 470 471 // end of sm timeout 472 473 // GAP Random Address updates 474 static gap_random_address_type_t gap_random_adress_type; 475 static btstack_timer_source_t gap_random_address_update_timer; 476 static uint32_t gap_random_adress_update_period; 477 478 static void gap_random_address_trigger(void){ 479 if (rau_state != RAU_IDLE) return; 480 log_info("gap_random_address_trigger"); 481 rau_state = RAU_GET_RANDOM; 482 sm_run(); 483 } 484 485 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 486 UNUSED(timer); 487 488 log_info("GAP Random Address Update due"); 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 gap_random_address_trigger(); 492 } 493 494 static void gap_random_address_update_start(void){ 495 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 496 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 497 btstack_run_loop_add_timer(&gap_random_address_update_timer); 498 } 499 500 static void gap_random_address_update_stop(void){ 501 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 502 } 503 504 505 static void sm_random_start(void * context){ 506 sm_random_context = context; 507 hci_send_cmd(&hci_le_rand); 508 } 509 510 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 511 // context is made availabe to aes128 result handler by this 512 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 513 sm_aes128_state = SM_AES128_ACTIVE; 514 sm_key_t key_flipped, plaintext_flipped; 515 reverse_128(key, key_flipped); 516 reverse_128(plaintext, plaintext_flipped); 517 sm_aes128_context = context; 518 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 519 } 520 521 // ah(k,r) helper 522 // r = padding || r 523 // r - 24 bit value 524 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 525 // r'= padding || r 526 memset(r_prime, 0, 16); 527 memcpy(&r_prime[13], r, 3); 528 } 529 530 // d1 helper 531 // d' = padding || r || d 532 // d,r - 16 bit values 533 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 534 // d'= padding || r || d 535 memset(d1_prime, 0, 16); 536 big_endian_store_16(d1_prime, 12, r); 537 big_endian_store_16(d1_prime, 14, d); 538 } 539 540 // dm helper 541 // r’ = padding || r 542 // r - 64 bit value 543 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 544 memset(r_prime, 0, 16); 545 memcpy(&r_prime[8], r, 8); 546 } 547 548 // calculate arguments for first AES128 operation in C1 function 549 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){ 550 551 // p1 = pres || preq || rat’ || iat’ 552 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 553 // cant octet of pres becomes the most significant octet of p1. 554 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 555 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 556 // p1 is 0x05000800000302070710000001010001." 557 558 sm_key_t p1; 559 reverse_56(pres, &p1[0]); 560 reverse_56(preq, &p1[7]); 561 p1[14] = rat; 562 p1[15] = iat; 563 log_info_key("p1", p1); 564 log_info_key("r", r); 565 566 // t1 = r xor p1 567 int i; 568 for (i=0;i<16;i++){ 569 t1[i] = r[i] ^ p1[i]; 570 } 571 log_info_key("t1", t1); 572 } 573 574 // calculate arguments for second AES128 operation in C1 function 575 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 576 // p2 = padding || ia || ra 577 // "The least significant octet of ra becomes the least significant octet of p2 and 578 // the most significant octet of padding becomes the most significant octet of p2. 579 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 580 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 581 582 sm_key_t p2; 583 memset(p2, 0, 16); 584 memcpy(&p2[4], ia, 6); 585 memcpy(&p2[10], ra, 6); 586 log_info_key("p2", p2); 587 588 // c1 = e(k, t2_xor_p2) 589 int i; 590 for (i=0;i<16;i++){ 591 t3[i] = t2[i] ^ p2[i]; 592 } 593 log_info_key("t3", t3); 594 } 595 596 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 597 log_info_key("r1", r1); 598 log_info_key("r2", r2); 599 memcpy(&r_prime[8], &r2[8], 8); 600 memcpy(&r_prime[0], &r1[8], 8); 601 } 602 603 #ifdef ENABLE_LE_SECURE_CONNECTIONS 604 // Software implementations of crypto toolbox for LE Secure Connection 605 // TODO: replace with code to use AES Engine of HCI Controller 606 typedef uint8_t sm_key24_t[3]; 607 typedef uint8_t sm_key56_t[7]; 608 typedef uint8_t sm_key256_t[32]; 609 610 #if 0 611 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 612 uint32_t rk[RKLENGTH(KEYBITS)]; 613 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 614 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 615 } 616 617 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 618 memcpy(k1, k0, 16); 619 sm_shift_left_by_one_bit_inplace(16, k1); 620 if (k0[0] & 0x80){ 621 k1[15] ^= 0x87; 622 } 623 memcpy(k2, k1, 16); 624 sm_shift_left_by_one_bit_inplace(16, k2); 625 if (k1[0] & 0x80){ 626 k2[15] ^= 0x87; 627 } 628 } 629 630 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 631 sm_key_t k0, k1, k2, zero; 632 memset(zero, 0, 16); 633 634 aes128_calc_cyphertext(key, zero, k0); 635 calc_subkeys(k0, k1, k2); 636 637 int cmac_block_count = (cmac_message_len + 15) / 16; 638 639 // step 3: .. 640 if (cmac_block_count==0){ 641 cmac_block_count = 1; 642 } 643 644 // step 4: set m_last 645 sm_key_t cmac_m_last; 646 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 647 int i; 648 if (sm_cmac_last_block_complete){ 649 for (i=0;i<16;i++){ 650 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 651 } 652 } else { 653 int valid_octets_in_last_block = cmac_message_len & 0x0f; 654 for (i=0;i<16;i++){ 655 if (i < valid_octets_in_last_block){ 656 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 657 continue; 658 } 659 if (i == valid_octets_in_last_block){ 660 cmac_m_last[i] = 0x80 ^ k2[i]; 661 continue; 662 } 663 cmac_m_last[i] = k2[i]; 664 } 665 } 666 667 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 668 // LOG_KEY(cmac_m_last); 669 670 // Step 5 671 sm_key_t cmac_x; 672 memset(cmac_x, 0, 16); 673 674 // Step 6 675 sm_key_t sm_cmac_y; 676 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 677 for (i=0;i<16;i++){ 678 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 679 } 680 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 681 } 682 for (i=0;i<16;i++){ 683 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 684 } 685 686 // Step 7 687 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 688 } 689 #endif 690 #endif 691 692 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){ 693 event[0] = type; 694 event[1] = event_size - 2; 695 little_endian_store_16(event, 2, con_handle); 696 event[4] = addr_type; 697 reverse_bd_addr(address, &event[5]); 698 } 699 700 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 701 UNUSED(channel); 702 703 // log event 704 hci_dump_packet(packet_type, 1, packet, size); 705 // dispatch to all event handlers 706 btstack_linked_list_iterator_t it; 707 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 708 while (btstack_linked_list_iterator_has_next(&it)){ 709 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 710 entry->callback(packet_type, 0, packet, size); 711 } 712 } 713 714 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 715 uint8_t event[11]; 716 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 717 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 718 } 719 720 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){ 721 uint8_t event[15]; 722 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 723 little_endian_store_32(event, 11, passkey); 724 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 725 } 726 727 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){ 728 // fetch addr and addr type from db 729 bd_addr_t identity_address; 730 int identity_address_type; 731 le_device_db_info(index, &identity_address_type, identity_address, NULL); 732 733 uint8_t event[19]; 734 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 735 event[11] = identity_address_type; 736 reverse_bd_addr(identity_address, &event[12]); 737 event[18] = index; 738 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 739 } 740 741 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){ 742 743 uint8_t event[18]; 744 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 745 event[11] = result; 746 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 747 } 748 749 // decide on stk generation based on 750 // - pairing request 751 // - io capabilities 752 // - OOB data availability 753 static void sm_setup_tk(void){ 754 755 // default: just works 756 setup->sm_stk_generation_method = JUST_WORKS; 757 758 #ifdef ENABLE_LE_SECURE_CONNECTIONS 759 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 760 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 761 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 762 memset(setup->sm_ra, 0, 16); 763 memset(setup->sm_rb, 0, 16); 764 #else 765 setup->sm_use_secure_connections = 0; 766 #endif 767 768 // If both devices have not set the MITM option in the Authentication Requirements 769 // Flags, then the IO capabilities shall be ignored and the Just Works association 770 // model shall be used. 771 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 772 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 773 log_info("SM: MITM not required by both -> JUST WORKS"); 774 return; 775 } 776 777 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 778 779 // If both devices have out of band authentication data, then the Authentication 780 // Requirements Flags shall be ignored when selecting the pairing method and the 781 // Out of Band pairing method shall be used. 782 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 783 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 784 log_info("SM: have OOB data"); 785 log_info_key("OOB", setup->sm_tk); 786 setup->sm_stk_generation_method = OOB; 787 return; 788 } 789 790 // Reset TK as it has been setup in sm_init_setup 791 sm_reset_tk(); 792 793 // Also use just works if unknown io capabilites 794 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)){ 795 return; 796 } 797 798 // Otherwise the IO capabilities of the devices shall be used to determine the 799 // pairing method as defined in Table 2.4. 800 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 801 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 802 803 #ifdef ENABLE_LE_SECURE_CONNECTIONS 804 // table not define by default 805 if (setup->sm_use_secure_connections){ 806 generation_method = stk_generation_method_with_secure_connection; 807 } 808 #endif 809 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)]; 810 811 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 812 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); 813 } 814 815 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 816 int flags = 0; 817 if (key_set & SM_KEYDIST_ENC_KEY){ 818 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 819 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 820 } 821 if (key_set & SM_KEYDIST_ID_KEY){ 822 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 823 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 824 } 825 if (key_set & SM_KEYDIST_SIGN){ 826 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 827 } 828 return flags; 829 } 830 831 static void sm_setup_key_distribution(uint8_t key_set){ 832 setup->sm_key_distribution_received_set = 0; 833 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 834 } 835 836 // CSRK Key Lookup 837 838 839 static int sm_address_resolution_idle(void){ 840 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 841 } 842 843 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){ 844 memcpy(sm_address_resolution_address, addr, 6); 845 sm_address_resolution_addr_type = addr_type; 846 sm_address_resolution_test = 0; 847 sm_address_resolution_mode = mode; 848 sm_address_resolution_context = context; 849 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 850 } 851 852 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 853 // check if already in list 854 btstack_linked_list_iterator_t it; 855 sm_lookup_entry_t * entry; 856 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 857 while(btstack_linked_list_iterator_has_next(&it)){ 858 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 859 if (entry->address_type != address_type) continue; 860 if (memcmp(entry->address, address, 6)) continue; 861 // already in list 862 return BTSTACK_BUSY; 863 } 864 entry = btstack_memory_sm_lookup_entry_get(); 865 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 866 entry->address_type = (bd_addr_type_t) address_type; 867 memcpy(entry->address, address, 6); 868 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 869 sm_run(); 870 return 0; 871 } 872 873 // 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 874 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 875 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 876 } 877 static inline void dkg_next_state(void){ 878 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 879 } 880 static inline void rau_next_state(void){ 881 rau_state = (random_address_update_t) (((int)rau_state) + 1); 882 } 883 884 // CMAC calculation using AES Engine 885 #ifdef ENABLE_CMAC_ENGINE 886 887 static inline void sm_cmac_next_state(void){ 888 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 889 } 890 891 static int sm_cmac_last_block_complete(void){ 892 if (sm_cmac_message_len == 0) return 0; 893 return (sm_cmac_message_len & 0x0f) == 0; 894 } 895 896 int sm_cmac_ready(void){ 897 return sm_cmac_state == CMAC_IDLE; 898 } 899 900 // generic cmac calculation 901 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])){ 902 // Generalized CMAC 903 memcpy(sm_cmac_k, key, 16); 904 memset(sm_cmac_x, 0, 16); 905 sm_cmac_block_current = 0; 906 sm_cmac_message_len = message_len; 907 sm_cmac_done_handler = done_callback; 908 sm_cmac_get_byte = get_byte_callback; 909 910 // step 2: n := ceil(len/const_Bsize); 911 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 912 913 // step 3: .. 914 if (sm_cmac_block_count==0){ 915 sm_cmac_block_count = 1; 916 } 917 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 918 919 // first, we need to compute l for k1, k2, and m_last 920 sm_cmac_state = CMAC_CALC_SUBKEYS; 921 922 // let's go 923 sm_run(); 924 } 925 #endif 926 927 // cmac for ATT Message signing 928 #ifdef ENABLE_LE_SIGNED_WRITE 929 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 930 if (offset >= sm_cmac_message_len) { 931 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 932 return 0; 933 } 934 935 offset = sm_cmac_message_len - 1 - offset; 936 937 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 938 if (offset < 3){ 939 return sm_cmac_header[offset]; 940 } 941 int actual_message_len_incl_header = sm_cmac_message_len - 4; 942 if (offset < actual_message_len_incl_header){ 943 return sm_cmac_message[offset - 3]; 944 } 945 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 946 } 947 948 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)){ 949 // ATT Message Signing 950 sm_cmac_header[0] = opcode; 951 little_endian_store_16(sm_cmac_header, 1, con_handle); 952 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 953 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 954 sm_cmac_message = message; 955 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 956 } 957 #endif 958 959 #ifdef ENABLE_CMAC_ENGINE 960 static void sm_cmac_handle_aes_engine_ready(void){ 961 switch (sm_cmac_state){ 962 case CMAC_CALC_SUBKEYS: { 963 sm_key_t const_zero; 964 memset(const_zero, 0, 16); 965 sm_cmac_next_state(); 966 sm_aes128_start(sm_cmac_k, const_zero, NULL); 967 break; 968 } 969 case CMAC_CALC_MI: { 970 int j; 971 sm_key_t y; 972 for (j=0;j<16;j++){ 973 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 974 } 975 sm_cmac_block_current++; 976 sm_cmac_next_state(); 977 sm_aes128_start(sm_cmac_k, y, NULL); 978 break; 979 } 980 case CMAC_CALC_MLAST: { 981 int i; 982 sm_key_t y; 983 for (i=0;i<16;i++){ 984 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 985 } 986 log_info_key("Y", y); 987 sm_cmac_block_current++; 988 sm_cmac_next_state(); 989 sm_aes128_start(sm_cmac_k, y, NULL); 990 break; 991 } 992 default: 993 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 994 break; 995 } 996 } 997 998 // CMAC Implementation using AES128 engine 999 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 1000 int i; 1001 int carry = 0; 1002 for (i=len-1; i >= 0 ; i--){ 1003 int new_carry = data[i] >> 7; 1004 data[i] = data[i] << 1 | carry; 1005 carry = new_carry; 1006 } 1007 } 1008 1009 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1010 switch (sm_cmac_state){ 1011 case CMAC_W4_SUBKEYS: { 1012 sm_key_t k1; 1013 memcpy(k1, data, 16); 1014 sm_shift_left_by_one_bit_inplace(16, k1); 1015 if (data[0] & 0x80){ 1016 k1[15] ^= 0x87; 1017 } 1018 sm_key_t k2; 1019 memcpy(k2, k1, 16); 1020 sm_shift_left_by_one_bit_inplace(16, k2); 1021 if (k1[0] & 0x80){ 1022 k2[15] ^= 0x87; 1023 } 1024 1025 log_info_key("k", sm_cmac_k); 1026 log_info_key("k1", k1); 1027 log_info_key("k2", k2); 1028 1029 // step 4: set m_last 1030 int i; 1031 if (sm_cmac_last_block_complete()){ 1032 for (i=0;i<16;i++){ 1033 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1034 } 1035 } else { 1036 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1037 for (i=0;i<16;i++){ 1038 if (i < valid_octets_in_last_block){ 1039 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1040 continue; 1041 } 1042 if (i == valid_octets_in_last_block){ 1043 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1044 continue; 1045 } 1046 sm_cmac_m_last[i] = k2[i]; 1047 } 1048 } 1049 1050 // next 1051 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1052 break; 1053 } 1054 case CMAC_W4_MI: 1055 memcpy(sm_cmac_x, data, 16); 1056 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1057 break; 1058 case CMAC_W4_MLAST: 1059 // done 1060 log_info("Setting CMAC Engine to IDLE"); 1061 sm_cmac_state = CMAC_IDLE; 1062 log_info_key("CMAC", data); 1063 sm_cmac_done_handler(data); 1064 break; 1065 default: 1066 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1067 break; 1068 } 1069 } 1070 #endif 1071 1072 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1073 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1074 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1075 switch (setup->sm_stk_generation_method){ 1076 case PK_RESP_INPUT: 1077 if (IS_RESPONDER(sm_conn->sm_role)){ 1078 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1079 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1080 } else { 1081 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)); 1082 } 1083 break; 1084 case PK_INIT_INPUT: 1085 if (IS_RESPONDER(sm_conn->sm_role)){ 1086 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1087 } else { 1088 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1089 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1090 } 1091 break; 1092 case OK_BOTH_INPUT: 1093 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1094 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1095 break; 1096 case NK_BOTH_INPUT: 1097 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1098 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)); 1099 break; 1100 case JUST_WORKS: 1101 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1102 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1103 break; 1104 case OOB: 1105 // client already provided OOB data, let's skip notification. 1106 break; 1107 } 1108 } 1109 1110 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1111 int recv_flags; 1112 if (IS_RESPONDER(sm_conn->sm_role)){ 1113 // slave / responder 1114 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1115 } else { 1116 // master / initiator 1117 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1118 } 1119 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1120 return recv_flags == setup->sm_key_distribution_received_set; 1121 } 1122 1123 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1124 if (sm_active_connection == con_handle){ 1125 sm_timeout_stop(); 1126 sm_active_connection = 0; 1127 log_info("sm: connection 0x%x released setup context", con_handle); 1128 } 1129 } 1130 1131 static int sm_key_distribution_flags_for_auth_req(void){ 1132 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1133 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1134 // encryption information only if bonding requested 1135 flags |= SM_KEYDIST_ENC_KEY; 1136 } 1137 return flags; 1138 } 1139 1140 static void sm_reset_setup(void){ 1141 // fill in sm setup 1142 setup->sm_state_vars = 0; 1143 setup->sm_keypress_notification = 0xff; 1144 sm_reset_tk(); 1145 } 1146 1147 static void sm_init_setup(sm_connection_t * sm_conn){ 1148 1149 // fill in sm setup 1150 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1151 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1152 1153 // query client for OOB data 1154 int have_oob_data = 0; 1155 if (sm_get_oob_data) { 1156 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1157 } 1158 1159 sm_pairing_packet_t * local_packet; 1160 if (IS_RESPONDER(sm_conn->sm_role)){ 1161 // slave 1162 local_packet = &setup->sm_s_pres; 1163 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1164 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1165 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1166 } else { 1167 // master 1168 local_packet = &setup->sm_m_preq; 1169 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1170 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1171 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1172 1173 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1174 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1175 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1176 } 1177 1178 uint8_t auth_req = sm_auth_req; 1179 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1180 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1181 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1182 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1183 } 1184 1185 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1186 1187 sm_pairing_packet_t * remote_packet; 1188 int remote_key_request; 1189 if (IS_RESPONDER(sm_conn->sm_role)){ 1190 // slave / responder 1191 remote_packet = &setup->sm_m_preq; 1192 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1193 } else { 1194 // master / initiator 1195 remote_packet = &setup->sm_s_pres; 1196 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1197 } 1198 1199 // check key size 1200 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1201 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1202 1203 // decide on STK generation method 1204 sm_setup_tk(); 1205 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1206 1207 // check if STK generation method is acceptable by client 1208 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1209 1210 // identical to responder 1211 sm_setup_key_distribution(remote_key_request); 1212 1213 // JUST WORKS doens't provide authentication 1214 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1215 1216 return 0; 1217 } 1218 1219 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1220 1221 // cache and reset context 1222 int matched_device_id = sm_address_resolution_test; 1223 address_resolution_mode_t mode = sm_address_resolution_mode; 1224 void * context = sm_address_resolution_context; 1225 1226 // reset context 1227 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1228 sm_address_resolution_context = NULL; 1229 sm_address_resolution_test = -1; 1230 hci_con_handle_t con_handle = 0; 1231 1232 sm_connection_t * sm_connection; 1233 #ifdef ENABLE_LE_CENTRAL 1234 sm_key_t ltk; 1235 #endif 1236 switch (mode){ 1237 case ADDRESS_RESOLUTION_GENERAL: 1238 break; 1239 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1240 sm_connection = (sm_connection_t *) context; 1241 con_handle = sm_connection->sm_handle; 1242 switch (event){ 1243 case ADDRESS_RESOLUTION_SUCEEDED: 1244 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1245 sm_connection->sm_le_db_index = matched_device_id; 1246 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1247 #ifdef ENABLE_LE_CENTRAL 1248 if (sm_connection->sm_role) break; 1249 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1250 sm_connection->sm_security_request_received = 0; 1251 sm_connection->sm_bonding_requested = 0; 1252 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1253 if (!sm_is_null_key(ltk)){ 1254 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1255 } else { 1256 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1257 } 1258 #endif 1259 break; 1260 case ADDRESS_RESOLUTION_FAILED: 1261 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1262 #ifdef ENABLE_LE_CENTRAL 1263 if (sm_connection->sm_role) break; 1264 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1265 sm_connection->sm_security_request_received = 0; 1266 sm_connection->sm_bonding_requested = 0; 1267 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1268 #endif 1269 break; 1270 } 1271 break; 1272 default: 1273 break; 1274 } 1275 1276 switch (event){ 1277 case ADDRESS_RESOLUTION_SUCEEDED: 1278 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1279 break; 1280 case ADDRESS_RESOLUTION_FAILED: 1281 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1282 break; 1283 } 1284 } 1285 1286 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1287 1288 int le_db_index = -1; 1289 1290 // lookup device based on IRK 1291 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1292 int i; 1293 for (i=0; i < le_device_db_count(); i++){ 1294 sm_key_t irk; 1295 bd_addr_t address; 1296 int address_type; 1297 le_device_db_info(i, &address_type, address, irk); 1298 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1299 log_info("sm: device found for IRK, updating"); 1300 le_db_index = i; 1301 break; 1302 } 1303 } 1304 } 1305 1306 // if not found, lookup via public address if possible 1307 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1308 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1309 int i; 1310 for (i=0; i < le_device_db_count(); i++){ 1311 bd_addr_t address; 1312 int address_type; 1313 le_device_db_info(i, &address_type, address, NULL); 1314 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1315 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1316 log_info("sm: device found for public address, updating"); 1317 le_db_index = i; 1318 break; 1319 } 1320 } 1321 } 1322 1323 // if not found, add to db 1324 if (le_db_index < 0) { 1325 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1326 } 1327 1328 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1329 1330 if (le_db_index >= 0){ 1331 1332 #ifdef ENABLE_LE_SIGNED_WRITE 1333 // store local CSRK 1334 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1335 log_info("sm: store local CSRK"); 1336 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1337 le_device_db_local_counter_set(le_db_index, 0); 1338 } 1339 1340 // store remote CSRK 1341 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1342 log_info("sm: store remote CSRK"); 1343 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1344 le_device_db_remote_counter_set(le_db_index, 0); 1345 } 1346 #endif 1347 // store encryption information for secure connections: LTK generated by ECDH 1348 if (setup->sm_use_secure_connections){ 1349 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1350 uint8_t zero_rand[8]; 1351 memset(zero_rand, 0, 8); 1352 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1353 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1354 } 1355 1356 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1357 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1358 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1359 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1360 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1361 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1362 1363 } 1364 } 1365 1366 // keep le_db_index 1367 sm_conn->sm_le_db_index = le_db_index; 1368 } 1369 1370 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1371 setup->sm_pairing_failed_reason = reason; 1372 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1373 } 1374 1375 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1376 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1377 } 1378 1379 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1380 1381 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1382 static int sm_passkey_used(stk_generation_method_t method); 1383 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1384 1385 static void sm_log_ec_keypair(void){ 1386 log_info("Elliptic curve: X"); 1387 log_info_hexdump(&ec_q[0],32); 1388 log_info("Elliptic curve: Y"); 1389 log_info_hexdump(&ec_q[32],32); 1390 } 1391 1392 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1393 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1394 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1395 } else { 1396 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1397 } 1398 } 1399 1400 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1401 if (IS_RESPONDER(sm_conn->sm_role)){ 1402 // Responder 1403 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1404 } else { 1405 // Initiator role 1406 switch (setup->sm_stk_generation_method){ 1407 case JUST_WORKS: 1408 sm_sc_prepare_dhkey_check(sm_conn); 1409 break; 1410 1411 case NK_BOTH_INPUT: 1412 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1413 break; 1414 case PK_INIT_INPUT: 1415 case PK_RESP_INPUT: 1416 case OK_BOTH_INPUT: 1417 if (setup->sm_passkey_bit < 20) { 1418 sm_sc_start_calculating_local_confirm(sm_conn); 1419 } else { 1420 sm_sc_prepare_dhkey_check(sm_conn); 1421 } 1422 break; 1423 case OOB: 1424 // TODO: implement SC OOB 1425 break; 1426 } 1427 } 1428 } 1429 1430 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1431 return sm_cmac_sc_buffer[offset]; 1432 } 1433 1434 static void sm_sc_cmac_done(uint8_t * hash){ 1435 log_info("sm_sc_cmac_done: "); 1436 log_info_hexdump(hash, 16); 1437 1438 sm_connection_t * sm_conn = sm_cmac_connection; 1439 sm_cmac_connection = NULL; 1440 link_key_type_t link_key_type; 1441 1442 switch (sm_conn->sm_engine_state){ 1443 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1444 memcpy(setup->sm_local_confirm, hash, 16); 1445 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1446 break; 1447 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1448 // check 1449 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1450 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1451 break; 1452 } 1453 sm_sc_state_after_receiving_random(sm_conn); 1454 break; 1455 case SM_SC_W4_CALCULATE_G2: { 1456 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1457 big_endian_store_32(setup->sm_tk, 12, vab); 1458 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1459 sm_trigger_user_response(sm_conn); 1460 break; 1461 } 1462 case SM_SC_W4_CALCULATE_F5_SALT: 1463 memcpy(setup->sm_t, hash, 16); 1464 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1465 break; 1466 case SM_SC_W4_CALCULATE_F5_MACKEY: 1467 memcpy(setup->sm_mackey, hash, 16); 1468 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1469 break; 1470 case SM_SC_W4_CALCULATE_F5_LTK: 1471 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1472 // Errata Service Release to the Bluetooth Specification: ESR09 1473 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1474 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1475 memcpy(setup->sm_ltk, hash, 16); 1476 memcpy(setup->sm_local_ltk, hash, 16); 1477 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1478 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1479 break; 1480 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1481 memcpy(setup->sm_local_dhkey_check, hash, 16); 1482 if (IS_RESPONDER(sm_conn->sm_role)){ 1483 // responder 1484 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1485 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1486 } else { 1487 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1488 } 1489 } else { 1490 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1491 } 1492 break; 1493 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1494 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1495 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1496 break; 1497 } 1498 if (IS_RESPONDER(sm_conn->sm_role)){ 1499 // responder 1500 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1501 } else { 1502 // initiator 1503 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1504 } 1505 break; 1506 case SM_SC_W4_CALCULATE_H6_ILK: 1507 memcpy(setup->sm_t, hash, 16); 1508 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1509 break; 1510 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1511 reverse_128(hash, setup->sm_t); 1512 link_key_type = sm_conn->sm_connection_authenticated ? 1513 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1514 if (IS_RESPONDER(sm_conn->sm_role)){ 1515 #ifdef ENABLE_CLASSIC 1516 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1517 #endif 1518 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1519 } else { 1520 #ifdef ENABLE_CLASSIC 1521 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1522 #endif 1523 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1524 } 1525 sm_done_for_handle(sm_conn->sm_handle); 1526 break; 1527 default: 1528 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1529 break; 1530 } 1531 sm_run(); 1532 } 1533 1534 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){ 1535 const uint16_t message_len = 65; 1536 sm_cmac_connection = sm_conn; 1537 memcpy(sm_cmac_sc_buffer, u, 32); 1538 memcpy(sm_cmac_sc_buffer+32, v, 32); 1539 sm_cmac_sc_buffer[64] = z; 1540 log_info("f4 key"); 1541 log_info_hexdump(x, 16); 1542 log_info("f4 message"); 1543 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1544 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1545 } 1546 1547 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1548 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1549 static const uint8_t f5_length[] = { 0x01, 0x00}; 1550 1551 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1552 #ifdef USE_MBEDTLS_FOR_ECDH 1553 // da * Pb 1554 mbedtls_mpi d; 1555 mbedtls_ecp_point Q; 1556 mbedtls_ecp_point DH; 1557 mbedtls_mpi_init(&d); 1558 mbedtls_ecp_point_init(&Q); 1559 mbedtls_ecp_point_init(&DH); 1560 mbedtls_mpi_read_binary(&d, ec_d, 32); 1561 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); 1562 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 1563 mbedtls_mpi_lset(&Q.Z, 1); 1564 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1565 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1566 mbedtls_ecp_point_free(&DH); 1567 mbedtls_mpi_free(&d); 1568 mbedtls_ecp_point_free(&Q); 1569 #endif 1570 #ifdef USE_MICROECC_FOR_ECDH 1571 uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); 1572 #endif 1573 log_info("dhkey"); 1574 log_info_hexdump(dhkey, 32); 1575 } 1576 1577 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1578 // calculate DHKEY 1579 sm_key256_t dhkey; 1580 sm_sc_calculate_dhkey(dhkey); 1581 1582 // calculate salt for f5 1583 const uint16_t message_len = 32; 1584 sm_cmac_connection = sm_conn; 1585 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1586 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1587 } 1588 1589 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){ 1590 const uint16_t message_len = 53; 1591 sm_cmac_connection = sm_conn; 1592 1593 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1594 sm_cmac_sc_buffer[0] = 0; 1595 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1596 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1597 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1598 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1599 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1600 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1601 log_info("f5 key"); 1602 log_info_hexdump(t, 16); 1603 log_info("f5 message for MacKey"); 1604 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1605 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1606 } 1607 1608 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1609 sm_key56_t bd_addr_master, bd_addr_slave; 1610 bd_addr_master[0] = setup->sm_m_addr_type; 1611 bd_addr_slave[0] = setup->sm_s_addr_type; 1612 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1613 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1614 if (IS_RESPONDER(sm_conn->sm_role)){ 1615 // responder 1616 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1617 } else { 1618 // initiator 1619 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1620 } 1621 } 1622 1623 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1624 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1625 const uint16_t message_len = 53; 1626 sm_cmac_connection = sm_conn; 1627 sm_cmac_sc_buffer[0] = 1; 1628 // 1..52 setup before 1629 log_info("f5 key"); 1630 log_info_hexdump(t, 16); 1631 log_info("f5 message for LTK"); 1632 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1633 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1634 } 1635 1636 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1637 f5_ltk(sm_conn, setup->sm_t); 1638 } 1639 1640 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){ 1641 const uint16_t message_len = 65; 1642 sm_cmac_connection = sm_conn; 1643 memcpy(sm_cmac_sc_buffer, n1, 16); 1644 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1645 memcpy(sm_cmac_sc_buffer+32, r, 16); 1646 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1647 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1648 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1649 log_info("f6 key"); 1650 log_info_hexdump(w, 16); 1651 log_info("f6 message"); 1652 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1653 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1654 } 1655 1656 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1657 // - U is 256 bits 1658 // - V is 256 bits 1659 // - X is 128 bits 1660 // - Y is 128 bits 1661 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){ 1662 const uint16_t message_len = 80; 1663 sm_cmac_connection = sm_conn; 1664 memcpy(sm_cmac_sc_buffer, u, 32); 1665 memcpy(sm_cmac_sc_buffer+32, v, 32); 1666 memcpy(sm_cmac_sc_buffer+64, y, 16); 1667 log_info("g2 key"); 1668 log_info_hexdump(x, 16); 1669 log_info("g2 message"); 1670 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1671 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1672 } 1673 1674 static void g2_calculate(sm_connection_t * sm_conn) { 1675 // calc Va if numeric comparison 1676 if (IS_RESPONDER(sm_conn->sm_role)){ 1677 // responder 1678 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1679 } else { 1680 // initiator 1681 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1682 } 1683 } 1684 1685 static void sm_sc_calculate_local_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 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1691 setup->sm_passkey_bit++; 1692 } 1693 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1694 } 1695 1696 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1697 uint8_t z = 0; 1698 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1699 // some form of passkey 1700 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1701 // sm_passkey_bit was increased before sending confirm value 1702 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1703 } 1704 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1705 } 1706 1707 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1708 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1709 } 1710 1711 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1712 // calculate DHKCheck 1713 sm_key56_t bd_addr_master, bd_addr_slave; 1714 bd_addr_master[0] = setup->sm_m_addr_type; 1715 bd_addr_slave[0] = setup->sm_s_addr_type; 1716 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1717 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1718 uint8_t iocap_a[3]; 1719 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1720 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1721 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1722 uint8_t iocap_b[3]; 1723 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1724 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1725 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1726 if (IS_RESPONDER(sm_conn->sm_role)){ 1727 // responder 1728 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); 1729 } else { 1730 // initiator 1731 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); 1732 } 1733 } 1734 1735 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1736 // validate E = f6() 1737 sm_key56_t bd_addr_master, bd_addr_slave; 1738 bd_addr_master[0] = setup->sm_m_addr_type; 1739 bd_addr_slave[0] = setup->sm_s_addr_type; 1740 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1741 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1742 1743 uint8_t iocap_a[3]; 1744 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1745 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1746 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1747 uint8_t iocap_b[3]; 1748 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1749 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1750 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1751 if (IS_RESPONDER(sm_conn->sm_role)){ 1752 // responder 1753 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); 1754 } else { 1755 // initiator 1756 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); 1757 } 1758 } 1759 1760 1761 // 1762 // Link Key Conversion Function h6 1763 // 1764 // h6(W, keyID) = AES-CMACW(keyID) 1765 // - W is 128 bits 1766 // - keyID is 32 bits 1767 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1768 const uint16_t message_len = 4; 1769 sm_cmac_connection = sm_conn; 1770 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1771 log_info("h6 key"); 1772 log_info_hexdump(w, 16); 1773 log_info("h6 message"); 1774 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1775 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1776 } 1777 1778 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1779 // Errata Service Release to the Bluetooth Specification: ESR09 1780 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1781 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1782 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1783 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1784 } 1785 1786 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1787 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1788 } 1789 1790 #endif 1791 1792 // key management legacy connections: 1793 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1794 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1795 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1796 // - responder reconnects: responder uses LTK receveived from master 1797 1798 // key management secure connections: 1799 // - both devices store same LTK from ECDH key exchange. 1800 1801 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1802 static void sm_load_security_info(sm_connection_t * sm_connection){ 1803 int encryption_key_size; 1804 int authenticated; 1805 int authorized; 1806 1807 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1808 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1809 &encryption_key_size, &authenticated, &authorized); 1810 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1811 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1812 sm_connection->sm_connection_authenticated = authenticated; 1813 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1814 } 1815 #endif 1816 1817 #ifdef ENABLE_LE_PERIPHERAL 1818 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1819 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1820 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1821 // re-establish used key encryption size 1822 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1823 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1824 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1825 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1826 log_info("sm: received ltk request with key size %u, authenticated %u", 1827 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1828 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1829 } 1830 #endif 1831 1832 static void sm_run(void){ 1833 1834 btstack_linked_list_iterator_t it; 1835 1836 // assert that we can send at least commands 1837 if (!hci_can_send_command_packet_now()) return; 1838 1839 // 1840 // non-connection related behaviour 1841 // 1842 1843 // distributed key generation 1844 switch (dkg_state){ 1845 case DKG_CALC_IRK: 1846 // already busy? 1847 if (sm_aes128_state == SM_AES128_IDLE) { 1848 // IRK = d1(IR, 1, 0) 1849 sm_key_t d1_prime; 1850 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1851 dkg_next_state(); 1852 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1853 return; 1854 } 1855 break; 1856 case DKG_CALC_DHK: 1857 // already busy? 1858 if (sm_aes128_state == SM_AES128_IDLE) { 1859 // DHK = d1(IR, 3, 0) 1860 sm_key_t d1_prime; 1861 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1862 dkg_next_state(); 1863 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1864 return; 1865 } 1866 break; 1867 default: 1868 break; 1869 } 1870 1871 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1872 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1873 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 1874 sm_random_start(NULL); 1875 #else 1876 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1877 hci_send_cmd(&hci_le_read_local_p256_public_key); 1878 #endif 1879 return; 1880 } 1881 #endif 1882 1883 // random address updates 1884 switch (rau_state){ 1885 case RAU_GET_RANDOM: 1886 rau_next_state(); 1887 sm_random_start(NULL); 1888 return; 1889 case RAU_GET_ENC: 1890 // already busy? 1891 if (sm_aes128_state == SM_AES128_IDLE) { 1892 sm_key_t r_prime; 1893 sm_ah_r_prime(sm_random_address, r_prime); 1894 rau_next_state(); 1895 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1896 return; 1897 } 1898 break; 1899 case RAU_SET_ADDRESS: 1900 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1901 rau_state = RAU_IDLE; 1902 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1903 return; 1904 default: 1905 break; 1906 } 1907 1908 #ifdef ENABLE_CMAC_ENGINE 1909 // CMAC 1910 switch (sm_cmac_state){ 1911 case CMAC_CALC_SUBKEYS: 1912 case CMAC_CALC_MI: 1913 case CMAC_CALC_MLAST: 1914 // already busy? 1915 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1916 sm_cmac_handle_aes_engine_ready(); 1917 return; 1918 default: 1919 break; 1920 } 1921 #endif 1922 1923 // CSRK Lookup 1924 // -- if csrk lookup ready, find connection that require csrk lookup 1925 if (sm_address_resolution_idle()){ 1926 hci_connections_get_iterator(&it); 1927 while(btstack_linked_list_iterator_has_next(&it)){ 1928 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1929 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1930 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1931 // and start lookup 1932 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); 1933 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1934 break; 1935 } 1936 } 1937 } 1938 1939 // -- if csrk lookup ready, resolved addresses for received addresses 1940 if (sm_address_resolution_idle()) { 1941 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1942 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1943 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1944 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1945 btstack_memory_sm_lookup_entry_free(entry); 1946 } 1947 } 1948 1949 // -- Continue with CSRK device lookup by public or resolvable private address 1950 if (!sm_address_resolution_idle()){ 1951 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1952 while (sm_address_resolution_test < le_device_db_count()){ 1953 int addr_type; 1954 bd_addr_t addr; 1955 sm_key_t irk; 1956 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1957 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1958 1959 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1960 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1961 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1962 break; 1963 } 1964 1965 if (sm_address_resolution_addr_type == 0){ 1966 sm_address_resolution_test++; 1967 continue; 1968 } 1969 1970 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1971 1972 log_info("LE Device Lookup: calculate AH"); 1973 log_info_key("IRK", irk); 1974 1975 sm_key_t r_prime; 1976 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1977 sm_address_resolution_ah_calculation_active = 1; 1978 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1979 return; 1980 } 1981 1982 if (sm_address_resolution_test >= le_device_db_count()){ 1983 log_info("LE Device Lookup: not found"); 1984 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1985 } 1986 } 1987 1988 // handle basic actions that don't requires the full context 1989 hci_connections_get_iterator(&it); 1990 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1991 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1992 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1993 switch(sm_connection->sm_engine_state){ 1994 // responder side 1995 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1996 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1997 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1998 return; 1999 2000 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2001 case SM_SC_RECEIVED_LTK_REQUEST: 2002 switch (sm_connection->sm_irk_lookup_state){ 2003 case IRK_LOOKUP_FAILED: 2004 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2005 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2006 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2007 return; 2008 default: 2009 break; 2010 } 2011 break; 2012 #endif 2013 default: 2014 break; 2015 } 2016 } 2017 2018 // 2019 // active connection handling 2020 // -- use loop to handle next connection if lock on setup context is released 2021 2022 while (1) { 2023 2024 // Find connections that requires setup context and make active if no other is locked 2025 hci_connections_get_iterator(&it); 2026 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 2027 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2028 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2029 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2030 int done = 1; 2031 int err; 2032 UNUSED(err); 2033 switch (sm_connection->sm_engine_state) { 2034 #ifdef ENABLE_LE_PERIPHERAL 2035 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2036 // send packet if possible, 2037 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2038 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2039 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2040 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2041 } else { 2042 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2043 } 2044 // don't lock sxetup context yet 2045 done = 0; 2046 break; 2047 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2048 sm_reset_setup(); 2049 sm_init_setup(sm_connection); 2050 // recover pairing request 2051 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2052 err = sm_stk_generation_init(sm_connection); 2053 if (err){ 2054 setup->sm_pairing_failed_reason = err; 2055 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2056 break; 2057 } 2058 sm_timeout_start(sm_connection); 2059 // generate random number first, if we need to show passkey 2060 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2061 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2062 break; 2063 } 2064 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2065 break; 2066 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2067 sm_reset_setup(); 2068 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2069 break; 2070 #endif 2071 #ifdef ENABLE_LE_CENTRAL 2072 case SM_INITIATOR_PH0_HAS_LTK: 2073 sm_reset_setup(); 2074 sm_load_security_info(sm_connection); 2075 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2076 break; 2077 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2078 sm_reset_setup(); 2079 sm_init_setup(sm_connection); 2080 sm_timeout_start(sm_connection); 2081 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2082 break; 2083 #endif 2084 2085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2086 case SM_SC_RECEIVED_LTK_REQUEST: 2087 switch (sm_connection->sm_irk_lookup_state){ 2088 case IRK_LOOKUP_SUCCEEDED: 2089 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2090 // start using context by loading security info 2091 sm_reset_setup(); 2092 sm_load_security_info(sm_connection); 2093 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2094 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2095 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2096 break; 2097 } 2098 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2099 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2100 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2101 // don't lock setup context yet 2102 return; 2103 default: 2104 // just wait until IRK lookup is completed 2105 // don't lock setup context yet 2106 done = 0; 2107 break; 2108 } 2109 break; 2110 #endif 2111 default: 2112 done = 0; 2113 break; 2114 } 2115 if (done){ 2116 sm_active_connection = sm_connection->sm_handle; 2117 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2118 } 2119 } 2120 2121 // 2122 // active connection handling 2123 // 2124 2125 if (sm_active_connection == 0) return; 2126 2127 // assert that we could send a SM PDU - not needed for all of the following 2128 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2129 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2130 return; 2131 } 2132 2133 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2134 if (!connection) return; 2135 2136 // send keypress notifications 2137 if (setup->sm_keypress_notification != 0xff){ 2138 uint8_t buffer[2]; 2139 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2140 buffer[1] = setup->sm_keypress_notification; 2141 setup->sm_keypress_notification = 0xff; 2142 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2143 return; 2144 } 2145 2146 sm_key_t plaintext; 2147 int key_distribution_flags; 2148 UNUSED(key_distribution_flags); 2149 2150 log_info("sm_run: state %u", connection->sm_engine_state); 2151 2152 switch (connection->sm_engine_state){ 2153 2154 // general 2155 case SM_GENERAL_SEND_PAIRING_FAILED: { 2156 uint8_t buffer[2]; 2157 buffer[0] = SM_CODE_PAIRING_FAILED; 2158 buffer[1] = setup->sm_pairing_failed_reason; 2159 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2160 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2161 sm_done_for_handle(connection->sm_handle); 2162 break; 2163 } 2164 2165 // responding state 2166 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2167 case SM_SC_W2_GET_RANDOM_A: 2168 sm_random_start(connection); 2169 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2170 break; 2171 case SM_SC_W2_GET_RANDOM_B: 2172 sm_random_start(connection); 2173 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2174 break; 2175 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2176 if (!sm_cmac_ready()) break; 2177 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2178 sm_sc_calculate_local_confirm(connection); 2179 break; 2180 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2181 if (!sm_cmac_ready()) break; 2182 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2183 sm_sc_calculate_remote_confirm(connection); 2184 break; 2185 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2186 if (!sm_cmac_ready()) break; 2187 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2188 sm_sc_calculate_f6_for_dhkey_check(connection); 2189 break; 2190 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2191 if (!sm_cmac_ready()) break; 2192 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2193 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2194 break; 2195 case SM_SC_W2_CALCULATE_F5_SALT: 2196 if (!sm_cmac_ready()) break; 2197 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2198 f5_calculate_salt(connection); 2199 break; 2200 case SM_SC_W2_CALCULATE_F5_MACKEY: 2201 if (!sm_cmac_ready()) break; 2202 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2203 f5_calculate_mackey(connection); 2204 break; 2205 case SM_SC_W2_CALCULATE_F5_LTK: 2206 if (!sm_cmac_ready()) break; 2207 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2208 f5_calculate_ltk(connection); 2209 break; 2210 case SM_SC_W2_CALCULATE_G2: 2211 if (!sm_cmac_ready()) break; 2212 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2213 g2_calculate(connection); 2214 break; 2215 case SM_SC_W2_CALCULATE_H6_ILK: 2216 if (!sm_cmac_ready()) break; 2217 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2218 h6_calculate_ilk(connection); 2219 break; 2220 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2221 if (!sm_cmac_ready()) break; 2222 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2223 h6_calculate_br_edr_link_key(connection); 2224 break; 2225 #endif 2226 2227 #ifdef ENABLE_LE_CENTRAL 2228 // initiator side 2229 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2230 sm_key_t peer_ltk_flipped; 2231 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2232 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2233 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2234 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2235 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2236 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2237 return; 2238 } 2239 2240 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2241 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2242 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2243 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2244 sm_timeout_reset(connection); 2245 break; 2246 #endif 2247 2248 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2249 2250 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2251 uint8_t buffer[65]; 2252 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2253 // 2254 reverse_256(&ec_q[0], &buffer[1]); 2255 reverse_256(&ec_q[32], &buffer[33]); 2256 2257 // stk generation method 2258 // passkey entry: notify app to show passkey or to request passkey 2259 switch (setup->sm_stk_generation_method){ 2260 case JUST_WORKS: 2261 case NK_BOTH_INPUT: 2262 if (IS_RESPONDER(connection->sm_role)){ 2263 // responder 2264 sm_sc_start_calculating_local_confirm(connection); 2265 } else { 2266 // initiator 2267 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2268 } 2269 break; 2270 case PK_INIT_INPUT: 2271 case PK_RESP_INPUT: 2272 case OK_BOTH_INPUT: 2273 // use random TK for display 2274 memcpy(setup->sm_ra, setup->sm_tk, 16); 2275 memcpy(setup->sm_rb, setup->sm_tk, 16); 2276 setup->sm_passkey_bit = 0; 2277 2278 if (IS_RESPONDER(connection->sm_role)){ 2279 // responder 2280 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2281 } else { 2282 // initiator 2283 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2284 } 2285 sm_trigger_user_response(connection); 2286 break; 2287 case OOB: 2288 // TODO: implement SC OOB 2289 break; 2290 } 2291 2292 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2293 sm_timeout_reset(connection); 2294 break; 2295 } 2296 case SM_SC_SEND_CONFIRMATION: { 2297 uint8_t buffer[17]; 2298 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2299 reverse_128(setup->sm_local_confirm, &buffer[1]); 2300 if (IS_RESPONDER(connection->sm_role)){ 2301 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2302 } else { 2303 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2304 } 2305 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2306 sm_timeout_reset(connection); 2307 break; 2308 } 2309 case SM_SC_SEND_PAIRING_RANDOM: { 2310 uint8_t buffer[17]; 2311 buffer[0] = SM_CODE_PAIRING_RANDOM; 2312 reverse_128(setup->sm_local_nonce, &buffer[1]); 2313 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2314 if (IS_RESPONDER(connection->sm_role)){ 2315 // responder 2316 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2317 } else { 2318 // initiator 2319 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2320 } 2321 } else { 2322 if (IS_RESPONDER(connection->sm_role)){ 2323 // responder 2324 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2325 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2326 } else { 2327 sm_sc_prepare_dhkey_check(connection); 2328 } 2329 } else { 2330 // initiator 2331 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2332 } 2333 } 2334 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2335 sm_timeout_reset(connection); 2336 break; 2337 } 2338 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2339 uint8_t buffer[17]; 2340 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2341 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2342 2343 if (IS_RESPONDER(connection->sm_role)){ 2344 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2345 } else { 2346 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2347 } 2348 2349 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2350 sm_timeout_reset(connection); 2351 break; 2352 } 2353 2354 #endif 2355 2356 #ifdef ENABLE_LE_PERIPHERAL 2357 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2358 // echo initiator for now 2359 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2360 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2361 2362 if (setup->sm_use_secure_connections){ 2363 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2364 // skip LTK/EDIV for SC 2365 log_info("sm: dropping encryption information flag"); 2366 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2367 } else { 2368 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2369 } 2370 2371 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); 2372 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); 2373 // update key distribution after ENC was dropped 2374 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2375 2376 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2377 sm_timeout_reset(connection); 2378 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2379 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2380 sm_trigger_user_response(connection); 2381 } 2382 return; 2383 #endif 2384 2385 case SM_PH2_SEND_PAIRING_RANDOM: { 2386 uint8_t buffer[17]; 2387 buffer[0] = SM_CODE_PAIRING_RANDOM; 2388 reverse_128(setup->sm_local_random, &buffer[1]); 2389 if (IS_RESPONDER(connection->sm_role)){ 2390 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2391 } else { 2392 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2393 } 2394 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2395 sm_timeout_reset(connection); 2396 break; 2397 } 2398 2399 case SM_PH2_GET_RANDOM_TK: 2400 case SM_PH2_C1_GET_RANDOM_A: 2401 case SM_PH2_C1_GET_RANDOM_B: 2402 case SM_PH3_GET_RANDOM: 2403 case SM_PH3_GET_DIV: 2404 sm_next_responding_state(connection); 2405 sm_random_start(connection); 2406 return; 2407 2408 case SM_PH2_C1_GET_ENC_B: 2409 case SM_PH2_C1_GET_ENC_D: 2410 // already busy? 2411 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2412 sm_next_responding_state(connection); 2413 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2414 return; 2415 2416 case SM_PH3_LTK_GET_ENC: 2417 case SM_RESPONDER_PH4_LTK_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, 0, 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_PH3_CSRK_GET_ENC: 2429 // already busy? 2430 if (sm_aes128_state == SM_AES128_IDLE) { 2431 sm_key_t d_prime; 2432 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2433 sm_next_responding_state(connection); 2434 sm_aes128_start(sm_persistent_er, d_prime, connection); 2435 return; 2436 } 2437 break; 2438 2439 case SM_PH2_C1_GET_ENC_C: 2440 // already busy? 2441 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2442 // calculate m_confirm using aes128 engine - step 1 2443 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); 2444 sm_next_responding_state(connection); 2445 sm_aes128_start(setup->sm_tk, plaintext, connection); 2446 break; 2447 case SM_PH2_C1_GET_ENC_A: 2448 // already busy? 2449 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2450 // calculate confirm using aes128 engine - step 1 2451 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); 2452 sm_next_responding_state(connection); 2453 sm_aes128_start(setup->sm_tk, plaintext, connection); 2454 break; 2455 case SM_PH2_CALC_STK: 2456 // already busy? 2457 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2458 // calculate STK 2459 if (IS_RESPONDER(connection->sm_role)){ 2460 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2461 } else { 2462 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2463 } 2464 sm_next_responding_state(connection); 2465 sm_aes128_start(setup->sm_tk, plaintext, connection); 2466 break; 2467 case SM_PH3_Y_GET_ENC: 2468 // already busy? 2469 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2470 // PH3B2 - calculate Y from - enc 2471 // Y = dm(DHK, Rand) 2472 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2473 sm_next_responding_state(connection); 2474 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2475 return; 2476 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2477 uint8_t buffer[17]; 2478 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2479 reverse_128(setup->sm_local_confirm, &buffer[1]); 2480 if (IS_RESPONDER(connection->sm_role)){ 2481 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2482 } else { 2483 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2484 } 2485 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2486 sm_timeout_reset(connection); 2487 return; 2488 } 2489 #ifdef ENABLE_LE_PERIPHERAL 2490 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2491 sm_key_t stk_flipped; 2492 reverse_128(setup->sm_ltk, stk_flipped); 2493 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2494 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2495 return; 2496 } 2497 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2498 sm_key_t ltk_flipped; 2499 reverse_128(setup->sm_ltk, ltk_flipped); 2500 connection->sm_engine_state = SM_RESPONDER_IDLE; 2501 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2502 return; 2503 } 2504 case SM_RESPONDER_PH4_Y_GET_ENC: 2505 // already busy? 2506 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2507 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2508 // Y = dm(DHK, Rand) 2509 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2510 sm_next_responding_state(connection); 2511 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2512 return; 2513 #endif 2514 #ifdef ENABLE_LE_CENTRAL 2515 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2516 sm_key_t stk_flipped; 2517 reverse_128(setup->sm_ltk, stk_flipped); 2518 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2519 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2520 return; 2521 } 2522 #endif 2523 2524 case SM_PH3_DISTRIBUTE_KEYS: 2525 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2526 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2527 uint8_t buffer[17]; 2528 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2529 reverse_128(setup->sm_ltk, &buffer[1]); 2530 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2531 sm_timeout_reset(connection); 2532 return; 2533 } 2534 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2535 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2536 uint8_t buffer[11]; 2537 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2538 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2539 reverse_64(setup->sm_local_rand, &buffer[3]); 2540 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2541 sm_timeout_reset(connection); 2542 return; 2543 } 2544 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2545 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2546 uint8_t buffer[17]; 2547 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2548 reverse_128(sm_persistent_irk, &buffer[1]); 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_IDENTITY_ADDRESS_INFORMATION){ 2554 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2555 bd_addr_t local_address; 2556 uint8_t buffer[8]; 2557 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2558 gap_le_get_own_address(&buffer[1], local_address); 2559 reverse_bd_addr(local_address, &buffer[2]); 2560 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2561 sm_timeout_reset(connection); 2562 return; 2563 } 2564 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2565 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2566 2567 // hack to reproduce test runs 2568 if (test_use_fixed_local_csrk){ 2569 memset(setup->sm_local_csrk, 0xcc, 16); 2570 } 2571 2572 uint8_t buffer[17]; 2573 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2574 reverse_128(setup->sm_local_csrk, &buffer[1]); 2575 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2576 sm_timeout_reset(connection); 2577 return; 2578 } 2579 2580 // keys are sent 2581 if (IS_RESPONDER(connection->sm_role)){ 2582 // slave -> receive master keys if any 2583 if (sm_key_distribution_all_received(connection)){ 2584 sm_key_distribution_handle_all_received(connection); 2585 connection->sm_engine_state = SM_RESPONDER_IDLE; 2586 sm_done_for_handle(connection->sm_handle); 2587 } else { 2588 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2589 } 2590 } else { 2591 // master -> all done 2592 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2593 sm_done_for_handle(connection->sm_handle); 2594 } 2595 break; 2596 2597 default: 2598 break; 2599 } 2600 2601 // check again if active connection was released 2602 if (sm_active_connection) break; 2603 } 2604 } 2605 2606 // note: aes engine is ready as we just got the aes result 2607 static void sm_handle_encryption_result(uint8_t * data){ 2608 2609 sm_aes128_state = SM_AES128_IDLE; 2610 2611 if (sm_address_resolution_ah_calculation_active){ 2612 sm_address_resolution_ah_calculation_active = 0; 2613 // compare calulated address against connecting device 2614 uint8_t hash[3]; 2615 reverse_24(data, hash); 2616 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2617 log_info("LE Device Lookup: matched resolvable private address"); 2618 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2619 return; 2620 } 2621 // no match, try next 2622 sm_address_resolution_test++; 2623 return; 2624 } 2625 2626 switch (dkg_state){ 2627 case DKG_W4_IRK: 2628 reverse_128(data, sm_persistent_irk); 2629 log_info_key("irk", sm_persistent_irk); 2630 dkg_next_state(); 2631 return; 2632 case DKG_W4_DHK: 2633 reverse_128(data, sm_persistent_dhk); 2634 log_info_key("dhk", sm_persistent_dhk); 2635 dkg_next_state(); 2636 // SM Init Finished 2637 return; 2638 default: 2639 break; 2640 } 2641 2642 switch (rau_state){ 2643 case RAU_W4_ENC: 2644 reverse_24(data, &sm_random_address[3]); 2645 rau_next_state(); 2646 return; 2647 default: 2648 break; 2649 } 2650 2651 #ifdef ENABLE_CMAC_ENGINE 2652 switch (sm_cmac_state){ 2653 case CMAC_W4_SUBKEYS: 2654 case CMAC_W4_MI: 2655 case CMAC_W4_MLAST: 2656 { 2657 sm_key_t t; 2658 reverse_128(data, t); 2659 sm_cmac_handle_encryption_result(t); 2660 } 2661 return; 2662 default: 2663 break; 2664 } 2665 #endif 2666 2667 // retrieve sm_connection provided to sm_aes128_start_encryption 2668 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2669 if (!connection) return; 2670 switch (connection->sm_engine_state){ 2671 case SM_PH2_C1_W4_ENC_A: 2672 case SM_PH2_C1_W4_ENC_C: 2673 { 2674 sm_key_t t2; 2675 reverse_128(data, t2); 2676 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2677 } 2678 sm_next_responding_state(connection); 2679 return; 2680 case SM_PH2_C1_W4_ENC_B: 2681 reverse_128(data, setup->sm_local_confirm); 2682 log_info_key("c1!", setup->sm_local_confirm); 2683 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2684 return; 2685 case SM_PH2_C1_W4_ENC_D: 2686 { 2687 sm_key_t peer_confirm_test; 2688 reverse_128(data, peer_confirm_test); 2689 log_info_key("c1!", peer_confirm_test); 2690 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2691 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2692 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2693 return; 2694 } 2695 if (IS_RESPONDER(connection->sm_role)){ 2696 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2697 } else { 2698 connection->sm_engine_state = SM_PH2_CALC_STK; 2699 } 2700 } 2701 return; 2702 case SM_PH2_W4_STK: 2703 reverse_128(data, setup->sm_ltk); 2704 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2705 log_info_key("stk", setup->sm_ltk); 2706 if (IS_RESPONDER(connection->sm_role)){ 2707 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2708 } else { 2709 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2710 } 2711 return; 2712 case SM_PH3_Y_W4_ENC:{ 2713 sm_key_t y128; 2714 reverse_128(data, y128); 2715 setup->sm_local_y = big_endian_read_16(y128, 14); 2716 log_info_hex16("y", setup->sm_local_y); 2717 // PH3B3 - calculate EDIV 2718 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2719 log_info_hex16("ediv", setup->sm_local_ediv); 2720 // PH3B4 - calculate LTK - enc 2721 // LTK = d1(ER, DIV, 0)) 2722 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2723 return; 2724 } 2725 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2726 sm_key_t y128; 2727 reverse_128(data, y128); 2728 setup->sm_local_y = big_endian_read_16(y128, 14); 2729 log_info_hex16("y", setup->sm_local_y); 2730 2731 // PH3B3 - calculate DIV 2732 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2733 log_info_hex16("ediv", setup->sm_local_ediv); 2734 // PH3B4 - calculate LTK - enc 2735 // LTK = d1(ER, DIV, 0)) 2736 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2737 return; 2738 } 2739 case SM_PH3_LTK_W4_ENC: 2740 reverse_128(data, setup->sm_ltk); 2741 log_info_key("ltk", setup->sm_ltk); 2742 // calc CSRK next 2743 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2744 return; 2745 case SM_PH3_CSRK_W4_ENC: 2746 reverse_128(data, setup->sm_local_csrk); 2747 log_info_key("csrk", setup->sm_local_csrk); 2748 if (setup->sm_key_distribution_send_set){ 2749 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2750 } else { 2751 // no keys to send, just continue 2752 if (IS_RESPONDER(connection->sm_role)){ 2753 // slave -> receive master keys 2754 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2755 } else { 2756 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2757 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2758 } else { 2759 // master -> all done 2760 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2761 sm_done_for_handle(connection->sm_handle); 2762 } 2763 } 2764 } 2765 return; 2766 #ifdef ENABLE_LE_PERIPHERAL 2767 case SM_RESPONDER_PH4_LTK_W4_ENC: 2768 reverse_128(data, setup->sm_ltk); 2769 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2770 log_info_key("ltk", setup->sm_ltk); 2771 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2772 return; 2773 #endif 2774 default: 2775 break; 2776 } 2777 } 2778 2779 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 2780 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ 2781 int offset = setup->sm_passkey_bit; 2782 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2783 while (size) { 2784 *buffer++ = setup->sm_peer_q[offset++]; 2785 size--; 2786 } 2787 setup->sm_passkey_bit = offset; 2788 return 0; 2789 } 2790 #ifdef USE_MBEDTLS_FOR_ECDH 2791 static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ 2792 UNUSED(context); 2793 return sm_generate_f_rng(buffer, size); 2794 } 2795 #endif 2796 #endif 2797 2798 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2799 static void sm_handle_random_result(uint8_t * data){ 2800 2801 #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 2802 2803 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2804 int num_bytes = setup->sm_passkey_bit; 2805 memcpy(&setup->sm_peer_q[num_bytes], data, 8); 2806 num_bytes += 8; 2807 setup->sm_passkey_bit = num_bytes; 2808 2809 if (num_bytes >= 64){ 2810 2811 // init pre-generated random data from sm_peer_q 2812 setup->sm_passkey_bit = 0; 2813 2814 // generate EC key 2815 #ifdef USE_MBEDTLS_FOR_ECDH 2816 mbedtls_mpi d; 2817 mbedtls_ecp_point P; 2818 mbedtls_mpi_init(&d); 2819 mbedtls_ecp_point_init(&P); 2820 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); 2821 log_info("gen keypair %x", res); 2822 mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); 2823 mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); 2824 mbedtls_mpi_write_binary(&d, ec_d, 32); 2825 mbedtls_ecp_point_free(&P); 2826 mbedtls_mpi_free(&d); 2827 #endif 2828 #ifdef USE_MICROECC_FOR_ECDH 2829 uECC_set_rng(&sm_generate_f_rng); 2830 uECC_make_key(ec_q, ec_d); 2831 #endif 2832 2833 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2834 log_info("Elliptic curve: d"); 2835 log_info_hexdump(ec_d,32); 2836 sm_log_ec_keypair(); 2837 } 2838 } 2839 #endif 2840 2841 switch (rau_state){ 2842 case RAU_W4_RANDOM: 2843 // non-resolvable vs. resolvable 2844 switch (gap_random_adress_type){ 2845 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2846 // resolvable: use random as prand and calc address hash 2847 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2848 memcpy(sm_random_address, data, 3); 2849 sm_random_address[0] &= 0x3f; 2850 sm_random_address[0] |= 0x40; 2851 rau_state = RAU_GET_ENC; 2852 break; 2853 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2854 default: 2855 // "The two most significant bits of the address shall be equal to ‘0’"" 2856 memcpy(sm_random_address, data, 6); 2857 sm_random_address[0] &= 0x3f; 2858 rau_state = RAU_SET_ADDRESS; 2859 break; 2860 } 2861 return; 2862 default: 2863 break; 2864 } 2865 2866 // retrieve sm_connection provided to sm_random_start 2867 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2868 if (!connection) return; 2869 switch (connection->sm_engine_state){ 2870 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2871 case SM_SC_W4_GET_RANDOM_A: 2872 memcpy(&setup->sm_local_nonce[0], data, 8); 2873 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2874 break; 2875 case SM_SC_W4_GET_RANDOM_B: 2876 memcpy(&setup->sm_local_nonce[8], data, 8); 2877 // initiator & jw/nc -> send pairing random 2878 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2879 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2880 break; 2881 } else { 2882 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2883 } 2884 break; 2885 #endif 2886 2887 case SM_PH2_W4_RANDOM_TK: 2888 { 2889 // map random to 0-999999 without speding much cycles on a modulus operation 2890 uint32_t tk = little_endian_read_32(data,0); 2891 tk = tk & 0xfffff; // 1048575 2892 if (tk >= 999999){ 2893 tk = tk - 999999; 2894 } 2895 sm_reset_tk(); 2896 big_endian_store_32(setup->sm_tk, 12, tk); 2897 if (IS_RESPONDER(connection->sm_role)){ 2898 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2899 } else { 2900 if (setup->sm_use_secure_connections){ 2901 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2902 } else { 2903 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2904 sm_trigger_user_response(connection); 2905 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2906 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2907 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2908 } 2909 } 2910 } 2911 return; 2912 } 2913 case SM_PH2_C1_W4_RANDOM_A: 2914 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2915 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2916 return; 2917 case SM_PH2_C1_W4_RANDOM_B: 2918 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2919 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2920 return; 2921 case SM_PH3_W4_RANDOM: 2922 reverse_64(data, setup->sm_local_rand); 2923 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2924 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2925 // no db for authenticated flag hack: store flag in bit 4 of LSB 2926 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2927 connection->sm_engine_state = SM_PH3_GET_DIV; 2928 return; 2929 case SM_PH3_W4_DIV: 2930 // use 16 bit from random value as div 2931 setup->sm_local_div = big_endian_read_16(data, 0); 2932 log_info_hex16("div", setup->sm_local_div); 2933 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2934 return; 2935 default: 2936 break; 2937 } 2938 } 2939 2940 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2941 2942 UNUSED(channel); 2943 UNUSED(size); 2944 2945 sm_connection_t * sm_conn; 2946 hci_con_handle_t con_handle; 2947 2948 switch (packet_type) { 2949 2950 case HCI_EVENT_PACKET: 2951 switch (hci_event_packet_get_type(packet)) { 2952 2953 case BTSTACK_EVENT_STATE: 2954 // bt stack activated, get started 2955 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2956 log_info("HCI Working!"); 2957 2958 // set local addr for le device db 2959 bd_addr_t local_bd_addr; 2960 gap_local_bd_addr(local_bd_addr); 2961 le_device_db_set_local_bd_addr(local_bd_addr); 2962 2963 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2964 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2965 if (!sm_have_ec_keypair){ 2966 setup->sm_passkey_bit = 0; 2967 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2968 } 2969 #endif 2970 // trigger Random Address generation if requested before 2971 switch (gap_random_adress_type){ 2972 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2973 rau_state = RAU_IDLE; 2974 break; 2975 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2976 rau_state = RAU_SET_ADDRESS; 2977 break; 2978 default: 2979 rau_state = RAU_GET_RANDOM; 2980 break; 2981 } 2982 sm_run(); 2983 } 2984 break; 2985 2986 case HCI_EVENT_LE_META: 2987 switch (packet[2]) { 2988 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2989 2990 log_info("sm: connected"); 2991 2992 if (packet[3]) return; // connection failed 2993 2994 con_handle = little_endian_read_16(packet, 4); 2995 sm_conn = sm_get_connection_for_handle(con_handle); 2996 if (!sm_conn) break; 2997 2998 sm_conn->sm_handle = con_handle; 2999 sm_conn->sm_role = packet[6]; 3000 sm_conn->sm_peer_addr_type = packet[7]; 3001 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3002 3003 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3004 3005 // reset security properties 3006 sm_conn->sm_connection_encrypted = 0; 3007 sm_conn->sm_connection_authenticated = 0; 3008 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3009 sm_conn->sm_le_db_index = -1; 3010 3011 // prepare CSRK lookup (does not involve setup) 3012 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3013 3014 // just connected -> everything else happens in sm_run() 3015 if (IS_RESPONDER(sm_conn->sm_role)){ 3016 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3017 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3018 if (sm_slave_request_security) { 3019 // request security if requested by app 3020 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3021 } else { 3022 // otherwise, wait for pairing request 3023 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3024 } 3025 } 3026 break; 3027 } else { 3028 // master 3029 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3030 } 3031 break; 3032 3033 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3034 con_handle = little_endian_read_16(packet, 3); 3035 sm_conn = sm_get_connection_for_handle(con_handle); 3036 if (!sm_conn) break; 3037 3038 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3039 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3040 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3041 break; 3042 } 3043 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3044 // PH2 SEND LTK as we need to exchange keys in PH3 3045 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3046 break; 3047 } 3048 3049 // store rand and ediv 3050 reverse_64(&packet[5], sm_conn->sm_local_rand); 3051 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3052 3053 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3054 // potentially stored LTK is from the master 3055 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3056 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3057 break; 3058 } 3059 3060 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3061 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3062 #else 3063 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3064 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3065 #endif 3066 break; 3067 3068 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3069 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3070 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3071 log_error("Read Local P256 Public Key failed"); 3072 break; 3073 } 3074 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); 3075 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); 3076 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3077 sm_log_ec_keypair(); 3078 break; 3079 #endif 3080 default: 3081 break; 3082 } 3083 break; 3084 3085 case HCI_EVENT_ENCRYPTION_CHANGE: 3086 con_handle = little_endian_read_16(packet, 3); 3087 sm_conn = sm_get_connection_for_handle(con_handle); 3088 if (!sm_conn) break; 3089 3090 sm_conn->sm_connection_encrypted = packet[5]; 3091 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3092 sm_conn->sm_actual_encryption_key_size); 3093 log_info("event handler, state %u", sm_conn->sm_engine_state); 3094 if (!sm_conn->sm_connection_encrypted) break; 3095 // continue if part of initial pairing 3096 switch (sm_conn->sm_engine_state){ 3097 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3098 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3099 sm_done_for_handle(sm_conn->sm_handle); 3100 break; 3101 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3102 if (IS_RESPONDER(sm_conn->sm_role)){ 3103 // slave 3104 if (setup->sm_use_secure_connections){ 3105 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3106 } else { 3107 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3108 } 3109 } else { 3110 // master 3111 if (sm_key_distribution_all_received(sm_conn)){ 3112 // skip receiving keys as there are none 3113 sm_key_distribution_handle_all_received(sm_conn); 3114 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3115 } else { 3116 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3117 } 3118 } 3119 break; 3120 default: 3121 break; 3122 } 3123 break; 3124 3125 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3126 con_handle = little_endian_read_16(packet, 3); 3127 sm_conn = sm_get_connection_for_handle(con_handle); 3128 if (!sm_conn) break; 3129 3130 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3131 log_info("event handler, state %u", sm_conn->sm_engine_state); 3132 // continue if part of initial pairing 3133 switch (sm_conn->sm_engine_state){ 3134 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3135 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3136 sm_done_for_handle(sm_conn->sm_handle); 3137 break; 3138 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3139 if (IS_RESPONDER(sm_conn->sm_role)){ 3140 // slave 3141 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3142 } else { 3143 // master 3144 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3145 } 3146 break; 3147 default: 3148 break; 3149 } 3150 break; 3151 3152 3153 case HCI_EVENT_DISCONNECTION_COMPLETE: 3154 con_handle = little_endian_read_16(packet, 3); 3155 sm_done_for_handle(con_handle); 3156 sm_conn = sm_get_connection_for_handle(con_handle); 3157 if (!sm_conn) break; 3158 3159 // delete stored bonding on disconnect with authentication failure in ph0 3160 if (sm_conn->sm_role == 0 3161 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3162 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3163 le_device_db_remove(sm_conn->sm_le_db_index); 3164 } 3165 3166 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3167 sm_conn->sm_handle = 0; 3168 break; 3169 3170 case HCI_EVENT_COMMAND_COMPLETE: 3171 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3172 sm_handle_encryption_result(&packet[6]); 3173 break; 3174 } 3175 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3176 sm_handle_random_result(&packet[6]); 3177 break; 3178 } 3179 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3180 // Hack for Nordic nRF5 series that doesn't have public address: 3181 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3182 // - we use this as default for advertisements/connections 3183 if (hci_get_manufacturer() == BLUETOOTH_COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3184 log_info("nRF5: using (fake) public address as random static address"); 3185 bd_addr_t addr; 3186 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3187 gap_random_address_set(addr); 3188 } 3189 } 3190 break; 3191 default: 3192 break; 3193 } 3194 break; 3195 default: 3196 break; 3197 } 3198 3199 sm_run(); 3200 } 3201 3202 static inline int sm_calc_actual_encryption_key_size(int other){ 3203 if (other < sm_min_encryption_key_size) return 0; 3204 if (other < sm_max_encryption_key_size) return other; 3205 return sm_max_encryption_key_size; 3206 } 3207 3208 3209 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3210 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3211 switch (method){ 3212 case JUST_WORKS: 3213 case NK_BOTH_INPUT: 3214 return 1; 3215 default: 3216 return 0; 3217 } 3218 } 3219 // responder 3220 3221 static int sm_passkey_used(stk_generation_method_t method){ 3222 switch (method){ 3223 case PK_RESP_INPUT: 3224 return 1; 3225 default: 3226 return 0; 3227 } 3228 } 3229 #endif 3230 3231 /** 3232 * @return ok 3233 */ 3234 static int sm_validate_stk_generation_method(void){ 3235 // check if STK generation method is acceptable by client 3236 switch (setup->sm_stk_generation_method){ 3237 case JUST_WORKS: 3238 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3239 case PK_RESP_INPUT: 3240 case PK_INIT_INPUT: 3241 case OK_BOTH_INPUT: 3242 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3243 case OOB: 3244 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3245 case NK_BOTH_INPUT: 3246 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3247 return 1; 3248 default: 3249 return 0; 3250 } 3251 } 3252 3253 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3254 3255 UNUSED(size); 3256 3257 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3258 sm_run(); 3259 } 3260 3261 if (packet_type != SM_DATA_PACKET) return; 3262 3263 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3264 if (!sm_conn) return; 3265 3266 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3267 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3268 return; 3269 } 3270 3271 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3272 3273 int err; 3274 UNUSED(err); 3275 3276 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3277 uint8_t buffer[5]; 3278 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3279 buffer[1] = 3; 3280 little_endian_store_16(buffer, 2, con_handle); 3281 buffer[4] = packet[1]; 3282 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3283 return; 3284 } 3285 3286 switch (sm_conn->sm_engine_state){ 3287 3288 // a sm timeout requries a new physical connection 3289 case SM_GENERAL_TIMEOUT: 3290 return; 3291 3292 #ifdef ENABLE_LE_CENTRAL 3293 3294 // Initiator 3295 case SM_INITIATOR_CONNECTED: 3296 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3297 sm_pdu_received_in_wrong_state(sm_conn); 3298 break; 3299 } 3300 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3301 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3302 break; 3303 } 3304 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3305 sm_key_t ltk; 3306 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3307 if (!sm_is_null_key(ltk)){ 3308 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3309 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3310 } else { 3311 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3312 } 3313 break; 3314 } 3315 // otherwise, store security request 3316 sm_conn->sm_security_request_received = 1; 3317 break; 3318 3319 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3320 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3321 sm_pdu_received_in_wrong_state(sm_conn); 3322 break; 3323 } 3324 // store pairing request 3325 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3326 err = sm_stk_generation_init(sm_conn); 3327 if (err){ 3328 setup->sm_pairing_failed_reason = err; 3329 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3330 break; 3331 } 3332 3333 // generate random number first, if we need to show passkey 3334 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3335 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3336 break; 3337 } 3338 3339 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3340 if (setup->sm_use_secure_connections){ 3341 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3342 if (setup->sm_stk_generation_method == JUST_WORKS){ 3343 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3344 sm_trigger_user_response(sm_conn); 3345 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3346 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3347 } 3348 } else { 3349 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3350 } 3351 break; 3352 } 3353 #endif 3354 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3355 sm_trigger_user_response(sm_conn); 3356 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3357 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3358 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3359 } 3360 break; 3361 3362 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3363 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3364 sm_pdu_received_in_wrong_state(sm_conn); 3365 break; 3366 } 3367 3368 // store s_confirm 3369 reverse_128(&packet[1], setup->sm_peer_confirm); 3370 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3371 break; 3372 3373 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3374 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3375 sm_pdu_received_in_wrong_state(sm_conn); 3376 break;; 3377 } 3378 3379 // received random value 3380 reverse_128(&packet[1], setup->sm_peer_random); 3381 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3382 break; 3383 #endif 3384 3385 #ifdef ENABLE_LE_PERIPHERAL 3386 // Responder 3387 case SM_RESPONDER_IDLE: 3388 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3389 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3390 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3391 sm_pdu_received_in_wrong_state(sm_conn); 3392 break;; 3393 } 3394 3395 // store pairing request 3396 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3397 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3398 break; 3399 #endif 3400 3401 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3402 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3403 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3404 sm_pdu_received_in_wrong_state(sm_conn); 3405 break; 3406 } 3407 3408 // store public key for DH Key calculation 3409 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3410 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3411 3412 // validate public key 3413 err = 0; 3414 3415 #ifdef USE_MBEDTLS_FOR_ECDH 3416 mbedtls_ecp_point Q; 3417 mbedtls_ecp_point_init( &Q ); 3418 mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); 3419 mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); 3420 mbedtls_mpi_lset(&Q.Z, 1); 3421 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3422 mbedtls_ecp_point_free( & Q); 3423 #endif 3424 #ifdef USE_MICROECC_FOR_ECDH 3425 err = uECC_valid_public_key(setup->sm_peer_q) == 0; 3426 #endif 3427 3428 if (err){ 3429 log_error("sm: peer public key invalid %x", err); 3430 // uses "unspecified reason", there is no "public key invalid" error code 3431 sm_pdu_received_in_wrong_state(sm_conn); 3432 break; 3433 } 3434 3435 if (IS_RESPONDER(sm_conn->sm_role)){ 3436 // responder 3437 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3438 } else { 3439 // initiator 3440 // stk generation method 3441 // passkey entry: notify app to show passkey or to request passkey 3442 switch (setup->sm_stk_generation_method){ 3443 case JUST_WORKS: 3444 case NK_BOTH_INPUT: 3445 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3446 break; 3447 case PK_RESP_INPUT: 3448 sm_sc_start_calculating_local_confirm(sm_conn); 3449 break; 3450 case PK_INIT_INPUT: 3451 case OK_BOTH_INPUT: 3452 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3453 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3454 break; 3455 } 3456 sm_sc_start_calculating_local_confirm(sm_conn); 3457 break; 3458 case OOB: 3459 // TODO: implement SC OOB 3460 break; 3461 } 3462 } 3463 break; 3464 3465 case SM_SC_W4_CONFIRMATION: 3466 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3467 sm_pdu_received_in_wrong_state(sm_conn); 3468 break; 3469 } 3470 // received confirm value 3471 reverse_128(&packet[1], setup->sm_peer_confirm); 3472 3473 if (IS_RESPONDER(sm_conn->sm_role)){ 3474 // responder 3475 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3476 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3477 // still waiting for passkey 3478 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3479 break; 3480 } 3481 } 3482 sm_sc_start_calculating_local_confirm(sm_conn); 3483 } else { 3484 // initiator 3485 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3486 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3487 } else { 3488 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3489 } 3490 } 3491 break; 3492 3493 case SM_SC_W4_PAIRING_RANDOM: 3494 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3495 sm_pdu_received_in_wrong_state(sm_conn); 3496 break; 3497 } 3498 3499 // received random value 3500 reverse_128(&packet[1], setup->sm_peer_nonce); 3501 3502 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3503 // only check for JUST WORK/NC in initiator role AND passkey entry 3504 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3505 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3506 } 3507 3508 sm_sc_state_after_receiving_random(sm_conn); 3509 break; 3510 3511 case SM_SC_W2_CALCULATE_G2: 3512 case SM_SC_W4_CALCULATE_G2: 3513 case SM_SC_W2_CALCULATE_F5_SALT: 3514 case SM_SC_W4_CALCULATE_F5_SALT: 3515 case SM_SC_W2_CALCULATE_F5_MACKEY: 3516 case SM_SC_W4_CALCULATE_F5_MACKEY: 3517 case SM_SC_W2_CALCULATE_F5_LTK: 3518 case SM_SC_W4_CALCULATE_F5_LTK: 3519 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3520 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3521 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3522 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3523 sm_pdu_received_in_wrong_state(sm_conn); 3524 break; 3525 } 3526 // store DHKey Check 3527 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3528 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3529 3530 // have we been only waiting for dhkey check command? 3531 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3532 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3533 } 3534 break; 3535 #endif 3536 3537 #ifdef ENABLE_LE_PERIPHERAL 3538 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3539 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3540 sm_pdu_received_in_wrong_state(sm_conn); 3541 break; 3542 } 3543 3544 // received confirm value 3545 reverse_128(&packet[1], setup->sm_peer_confirm); 3546 3547 // notify client to hide shown passkey 3548 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3549 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3550 } 3551 3552 // handle user cancel pairing? 3553 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3554 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3555 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3556 break; 3557 } 3558 3559 // wait for user action? 3560 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3561 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3562 break; 3563 } 3564 3565 // calculate and send local_confirm 3566 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3567 break; 3568 3569 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3570 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3571 sm_pdu_received_in_wrong_state(sm_conn); 3572 break;; 3573 } 3574 3575 // received random value 3576 reverse_128(&packet[1], setup->sm_peer_random); 3577 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3578 break; 3579 #endif 3580 3581 case SM_PH3_RECEIVE_KEYS: 3582 switch(packet[0]){ 3583 case SM_CODE_ENCRYPTION_INFORMATION: 3584 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3585 reverse_128(&packet[1], setup->sm_peer_ltk); 3586 break; 3587 3588 case SM_CODE_MASTER_IDENTIFICATION: 3589 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3590 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3591 reverse_64(&packet[3], setup->sm_peer_rand); 3592 break; 3593 3594 case SM_CODE_IDENTITY_INFORMATION: 3595 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3596 reverse_128(&packet[1], setup->sm_peer_irk); 3597 break; 3598 3599 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3600 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3601 setup->sm_peer_addr_type = packet[1]; 3602 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3603 break; 3604 3605 case SM_CODE_SIGNING_INFORMATION: 3606 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3607 reverse_128(&packet[1], setup->sm_peer_csrk); 3608 break; 3609 default: 3610 // Unexpected PDU 3611 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3612 break; 3613 } 3614 // done with key distribution? 3615 if (sm_key_distribution_all_received(sm_conn)){ 3616 3617 sm_key_distribution_handle_all_received(sm_conn); 3618 3619 if (IS_RESPONDER(sm_conn->sm_role)){ 3620 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3621 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3622 } else { 3623 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3624 sm_done_for_handle(sm_conn->sm_handle); 3625 } 3626 } else { 3627 if (setup->sm_use_secure_connections){ 3628 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3629 } else { 3630 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3631 } 3632 } 3633 } 3634 break; 3635 default: 3636 // Unexpected PDU 3637 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3638 break; 3639 } 3640 3641 // try to send preparared packet 3642 sm_run(); 3643 } 3644 3645 // Security Manager Client API 3646 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3647 sm_get_oob_data = get_oob_data_callback; 3648 } 3649 3650 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3651 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3652 } 3653 3654 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3655 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3656 } 3657 3658 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3659 sm_min_encryption_key_size = min_size; 3660 sm_max_encryption_key_size = max_size; 3661 } 3662 3663 void sm_set_authentication_requirements(uint8_t auth_req){ 3664 sm_auth_req = auth_req; 3665 } 3666 3667 void sm_set_io_capabilities(io_capability_t io_capability){ 3668 sm_io_capabilities = io_capability; 3669 } 3670 3671 #ifdef ENABLE_LE_PERIPHERAL 3672 void sm_set_request_security(int enable){ 3673 sm_slave_request_security = enable; 3674 } 3675 #endif 3676 3677 void sm_set_er(sm_key_t er){ 3678 memcpy(sm_persistent_er, er, 16); 3679 } 3680 3681 void sm_set_ir(sm_key_t ir){ 3682 memcpy(sm_persistent_ir, ir, 16); 3683 } 3684 3685 // Testing support only 3686 void sm_test_set_irk(sm_key_t irk){ 3687 memcpy(sm_persistent_irk, irk, 16); 3688 sm_persistent_irk_ready = 1; 3689 } 3690 3691 void sm_test_use_fixed_local_csrk(void){ 3692 test_use_fixed_local_csrk = 1; 3693 } 3694 3695 void sm_init(void){ 3696 // set some (BTstack default) ER and IR 3697 int i; 3698 sm_key_t er; 3699 sm_key_t ir; 3700 for (i=0;i<16;i++){ 3701 er[i] = 0x30 + i; 3702 ir[i] = 0x90 + i; 3703 } 3704 sm_set_er(er); 3705 sm_set_ir(ir); 3706 // defaults 3707 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3708 | SM_STK_GENERATION_METHOD_OOB 3709 | SM_STK_GENERATION_METHOD_PASSKEY 3710 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3711 3712 sm_max_encryption_key_size = 16; 3713 sm_min_encryption_key_size = 7; 3714 3715 #ifdef ENABLE_CMAC_ENGINE 3716 sm_cmac_state = CMAC_IDLE; 3717 #endif 3718 dkg_state = DKG_W4_WORKING; 3719 rau_state = RAU_W4_WORKING; 3720 sm_aes128_state = SM_AES128_IDLE; 3721 sm_address_resolution_test = -1; // no private address to resolve yet 3722 sm_address_resolution_ah_calculation_active = 0; 3723 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3724 sm_address_resolution_general_queue = NULL; 3725 3726 gap_random_adress_update_period = 15 * 60 * 1000L; 3727 sm_active_connection = 0; 3728 3729 test_use_fixed_local_csrk = 0; 3730 3731 // register for HCI Events from HCI 3732 hci_event_callback_registration.callback = &sm_event_packet_handler; 3733 hci_add_event_handler(&hci_event_callback_registration); 3734 3735 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3736 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3737 3738 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3739 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3740 #endif 3741 3742 #ifdef USE_MBEDTLS_FOR_ECDH 3743 #ifndef HAVE_MALLOC 3744 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3745 #endif 3746 mbedtls_ecp_group_init(&mbedtls_ec_group); 3747 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3748 #endif 3749 } 3750 3751 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3752 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3753 memcpy(&ec_q[0], qx, 32); 3754 memcpy(&ec_q[32], qy, 32); 3755 memcpy(ec_d, d, 32); 3756 sm_have_ec_keypair = 1; 3757 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3758 #else 3759 UNUSED(qx); 3760 UNUSED(qy); 3761 UNUSED(d); 3762 #endif 3763 } 3764 3765 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3766 #ifndef USE_MBEDTLS_FOR_ECDH 3767 static void parse_hex(uint8_t * buffer, const char * hex_string){ 3768 while (*hex_string){ 3769 int high_nibble = nibble_for_char(*hex_string++); 3770 int low_nibble = nibble_for_char(*hex_string++); 3771 *buffer++ = (high_nibble << 4) | low_nibble; 3772 } 3773 } 3774 #endif 3775 #endif 3776 3777 void sm_test_use_fixed_ec_keypair(void){ 3778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3779 const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; 3780 const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; 3781 const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; 3782 #ifdef USE_MBEDTLS_FOR_ECDH 3783 // use test keypair from spec 3784 mbedtls_mpi x; 3785 mbedtls_mpi_init(&x); 3786 mbedtls_mpi_read_string( &x, 16, ec_d_string); 3787 mbedtls_mpi_write_binary(&x, ec_d, 32); 3788 mbedtls_mpi_read_string( &x, 16, ec_qx_string); 3789 mbedtls_mpi_write_binary(&x, &ec_q[0], 32); 3790 mbedtls_mpi_read_string( &x, 16, ec_qy_string); 3791 mbedtls_mpi_write_binary(&x, &ec_q[32], 32); 3792 mbedtls_mpi_free(&x); 3793 #else 3794 parse_hex(ec_d, ec_d_string); 3795 parse_hex(&ec_q[0], ec_qx_string); 3796 parse_hex(&ec_q[32], ec_qy_string); 3797 #endif 3798 sm_have_ec_keypair = 1; 3799 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3800 #endif 3801 } 3802 3803 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3804 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3805 if (!hci_con) return NULL; 3806 return &hci_con->sm_connection; 3807 } 3808 3809 // @returns 0 if not encrypted, 7-16 otherwise 3810 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3811 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3812 if (!sm_conn) return 0; // wrong connection 3813 if (!sm_conn->sm_connection_encrypted) return 0; 3814 return sm_conn->sm_actual_encryption_key_size; 3815 } 3816 3817 int sm_authenticated(hci_con_handle_t con_handle){ 3818 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3819 if (!sm_conn) return 0; // wrong connection 3820 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3821 return sm_conn->sm_connection_authenticated; 3822 } 3823 3824 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3825 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3826 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3827 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3828 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3829 return sm_conn->sm_connection_authorization_state; 3830 } 3831 3832 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3833 switch (sm_conn->sm_engine_state){ 3834 case SM_GENERAL_IDLE: 3835 case SM_RESPONDER_IDLE: 3836 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3837 sm_run(); 3838 break; 3839 default: 3840 break; 3841 } 3842 } 3843 3844 /** 3845 * @brief Trigger Security Request 3846 */ 3847 void sm_send_security_request(hci_con_handle_t con_handle){ 3848 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3849 if (!sm_conn) return; 3850 sm_send_security_request_for_connection(sm_conn); 3851 } 3852 3853 // request pairing 3854 void sm_request_pairing(hci_con_handle_t con_handle){ 3855 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3856 if (!sm_conn) return; // wrong connection 3857 3858 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3859 if (IS_RESPONDER(sm_conn->sm_role)){ 3860 sm_send_security_request_for_connection(sm_conn); 3861 } else { 3862 // used as a trigger to start central/master/initiator security procedures 3863 uint16_t ediv; 3864 sm_key_t ltk; 3865 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3866 switch (sm_conn->sm_irk_lookup_state){ 3867 case IRK_LOOKUP_FAILED: 3868 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3869 break; 3870 case IRK_LOOKUP_SUCCEEDED: 3871 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3872 if (!sm_is_null_key(ltk) || ediv){ 3873 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3874 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3875 } else { 3876 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3877 } 3878 break; 3879 default: 3880 sm_conn->sm_bonding_requested = 1; 3881 break; 3882 } 3883 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3884 sm_conn->sm_bonding_requested = 1; 3885 } 3886 } 3887 sm_run(); 3888 } 3889 3890 // called by client app on authorization request 3891 void sm_authorization_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 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3895 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3896 } 3897 3898 void sm_authorization_grant(hci_con_handle_t con_handle){ 3899 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3900 if (!sm_conn) return; // wrong connection 3901 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3902 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3903 } 3904 3905 // GAP Bonding API 3906 3907 void sm_bonding_decline(hci_con_handle_t con_handle){ 3908 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3909 if (!sm_conn) return; // wrong connection 3910 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3911 3912 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3913 switch (setup->sm_stk_generation_method){ 3914 case PK_RESP_INPUT: 3915 case PK_INIT_INPUT: 3916 case OK_BOTH_INPUT: 3917 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3918 break; 3919 case NK_BOTH_INPUT: 3920 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3921 break; 3922 case JUST_WORKS: 3923 case OOB: 3924 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3925 break; 3926 } 3927 } 3928 sm_run(); 3929 } 3930 3931 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3932 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3933 if (!sm_conn) return; // wrong connection 3934 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3935 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3936 if (setup->sm_use_secure_connections){ 3937 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3938 } else { 3939 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3940 } 3941 } 3942 3943 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3944 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3945 sm_sc_prepare_dhkey_check(sm_conn); 3946 } 3947 #endif 3948 3949 sm_run(); 3950 } 3951 3952 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3953 // for now, it's the same 3954 sm_just_works_confirm(con_handle); 3955 } 3956 3957 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3958 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3959 if (!sm_conn) return; // wrong connection 3960 sm_reset_tk(); 3961 big_endian_store_32(setup->sm_tk, 12, passkey); 3962 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3963 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3964 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3965 } 3966 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3967 memcpy(setup->sm_ra, setup->sm_tk, 16); 3968 memcpy(setup->sm_rb, setup->sm_tk, 16); 3969 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3970 sm_sc_start_calculating_local_confirm(sm_conn); 3971 } 3972 #endif 3973 sm_run(); 3974 } 3975 3976 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3977 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3978 if (!sm_conn) return; // wrong connection 3979 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3980 setup->sm_keypress_notification = action; 3981 sm_run(); 3982 } 3983 3984 /** 3985 * @brief Identify device in LE Device DB 3986 * @param handle 3987 * @returns index from le_device_db or -1 if not found/identified 3988 */ 3989 int sm_le_device_index(hci_con_handle_t con_handle ){ 3990 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3991 if (!sm_conn) return -1; 3992 return sm_conn->sm_le_db_index; 3993 } 3994 3995 static int gap_random_address_type_requires_updates(void){ 3996 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3997 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3998 return 1; 3999 } 4000 4001 static uint8_t own_address_type(void){ 4002 switch (gap_random_adress_type){ 4003 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4004 return BD_ADDR_TYPE_LE_PUBLIC; 4005 default: 4006 return BD_ADDR_TYPE_LE_RANDOM; 4007 } 4008 } 4009 4010 // GAP LE API 4011 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4012 gap_random_address_update_stop(); 4013 gap_random_adress_type = random_address_type; 4014 hci_le_set_own_address_type(own_address_type()); 4015 if (!gap_random_address_type_requires_updates()) return; 4016 gap_random_address_update_start(); 4017 gap_random_address_trigger(); 4018 } 4019 4020 gap_random_address_type_t gap_random_address_get_mode(void){ 4021 return gap_random_adress_type; 4022 } 4023 4024 void gap_random_address_set_update_period(int period_ms){ 4025 gap_random_adress_update_period = period_ms; 4026 if (!gap_random_address_type_requires_updates()) return; 4027 gap_random_address_update_stop(); 4028 gap_random_address_update_start(); 4029 } 4030 4031 void gap_random_address_set(bd_addr_t addr){ 4032 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4033 memcpy(sm_random_address, addr, 6); 4034 if (rau_state == RAU_W4_WORKING) return; 4035 rau_state = RAU_SET_ADDRESS; 4036 sm_run(); 4037 } 4038 4039 #ifdef ENABLE_LE_PERIPHERAL 4040 /* 4041 * @brief Set Advertisement Paramters 4042 * @param adv_int_min 4043 * @param adv_int_max 4044 * @param adv_type 4045 * @param direct_address_type 4046 * @param direct_address 4047 * @param channel_map 4048 * @param filter_policy 4049 * 4050 * @note own_address_type is used from gap_random_address_set_mode 4051 */ 4052 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4053 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4054 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4055 direct_address_typ, direct_address, channel_map, filter_policy); 4056 } 4057 #endif 4058 4059