1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "hci_dump.h" 52 #include "l2cap.h" 53 54 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 55 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 56 #endif 57 58 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 59 #define IS_RESPONDER(role) (role) 60 #else 61 #ifdef ENABLE_LE_CENTRAL 62 // only central - never responder (avoid 'unused variable' warnings) 63 #define IS_RESPONDER(role) (0 && role) 64 #else 65 // only peripheral - always responder (avoid 'unused variable' warnings) 66 #define IS_RESPONDER(role) (1 || role) 67 #endif 68 #endif 69 70 #ifdef ENABLE_LE_SECURE_CONNECTIONS 71 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 72 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 73 #else 74 #define USE_MBEDTLS_FOR_ECDH 75 #endif 76 #endif 77 78 // Software ECDH implementation provided by mbedtls 79 #ifdef USE_MBEDTLS_FOR_ECDH 80 #include "mbedtls/config.h" 81 #include "mbedtls/platform.h" 82 #include "mbedtls/ecp.h" 83 #include "sm_mbedtls_allocator.h" 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define ENABLE_CMAC_ENGINE 88 #endif 89 90 // 91 // SM internal types and globals 92 // 93 94 typedef enum { 95 DKG_W4_WORKING, 96 DKG_CALC_IRK, 97 DKG_W4_IRK, 98 DKG_CALC_DHK, 99 DKG_W4_DHK, 100 DKG_READY 101 } derived_key_generation_t; 102 103 typedef enum { 104 RAU_W4_WORKING, 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 OK_BOTH_INPUT, // Only input on both, both input PK 128 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on both sides 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_W4_KEY, 160 EC_KEY_GENERATION_DONE, 161 } ec_key_generation_state_t; 162 163 typedef enum { 164 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 165 } sm_state_var_t; 166 167 // 168 // GLOBAL DATA 169 // 170 171 static uint8_t test_use_fixed_local_csrk; 172 173 // configuration 174 static uint8_t sm_accepted_stk_generation_methods; 175 static uint8_t sm_max_encryption_key_size; 176 static uint8_t sm_min_encryption_key_size; 177 static uint8_t sm_auth_req = 0; 178 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 179 static uint8_t sm_slave_request_security; 180 #ifdef ENABLE_LE_SECURE_CONNECTIONS 181 static uint8_t sm_have_ec_keypair; 182 #endif 183 184 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 185 static sm_key_t sm_persistent_er; 186 static sm_key_t sm_persistent_ir; 187 188 // derived from sm_persistent_ir 189 static sm_key_t sm_persistent_dhk; 190 static sm_key_t sm_persistent_irk; 191 static uint8_t sm_persistent_irk_ready = 0; // used for testing 192 static derived_key_generation_t dkg_state; 193 194 // derived from sm_persistent_er 195 // .. 196 197 // random address update 198 static random_address_update_t rau_state; 199 static bd_addr_t sm_random_address; 200 201 // CMAC Calculation: General 202 #ifdef ENABLE_CMAC_ENGINE 203 static cmac_state_t sm_cmac_state; 204 static uint16_t sm_cmac_message_len; 205 static sm_key_t sm_cmac_k; 206 static sm_key_t sm_cmac_x; 207 static sm_key_t sm_cmac_m_last; 208 static uint8_t sm_cmac_block_current; 209 static uint8_t sm_cmac_block_count; 210 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 211 static void (*sm_cmac_done_handler)(uint8_t * hash); 212 #endif 213 214 // CMAC for ATT Signed Writes 215 #ifdef ENABLE_LE_SIGNED_WRITE 216 static uint8_t sm_cmac_header[3]; 217 static const uint8_t * sm_cmac_message; 218 static uint8_t sm_cmac_sign_counter[4]; 219 #endif 220 221 // CMAC for Secure Connection functions 222 #ifdef ENABLE_LE_SECURE_CONNECTIONS 223 static sm_connection_t * sm_cmac_connection; 224 static uint8_t sm_cmac_sc_buffer[80]; 225 #endif 226 227 // resolvable private address lookup / CSRK calculation 228 static int sm_address_resolution_test; 229 static int sm_address_resolution_ah_calculation_active; 230 static uint8_t sm_address_resolution_addr_type; 231 static bd_addr_t sm_address_resolution_address; 232 static void * sm_address_resolution_context; 233 static address_resolution_mode_t sm_address_resolution_mode; 234 static btstack_linked_list_t sm_address_resolution_general_queue; 235 236 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 237 static sm_aes128_state_t sm_aes128_state; 238 static void * sm_aes128_context; 239 240 // random engine. store context (ususally sm_connection_t) 241 static void * sm_random_context; 242 243 // to receive hci events 244 static btstack_packet_callback_registration_t hci_event_callback_registration; 245 246 /* to dispatch sm event */ 247 static btstack_linked_list_t sm_event_handlers; 248 249 // LE Secure Connections 250 #ifdef ENABLE_LE_SECURE_CONNECTIONS 251 static ec_key_generation_state_t ec_key_generation_state; 252 static uint8_t ec_d[32]; 253 static uint8_t ec_qx[32]; 254 static uint8_t ec_qy[32]; 255 #endif 256 257 // Software ECDH implementation provided by mbedtls 258 #ifdef USE_MBEDTLS_FOR_ECDH 259 // group is always valid 260 static mbedtls_ecp_group mbedtls_ec_group; 261 #ifndef HAVE_MALLOC 262 // COMP Method with Window 2 263 // 1300 bytes with 23 allocations 264 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 265 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 266 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 267 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 268 #endif 269 #endif 270 271 // 272 // Volume 3, Part H, Chapter 24 273 // "Security shall be initiated by the Security Manager in the device in the master role. 274 // The device in the slave role shall be the responding device." 275 // -> master := initiator, slave := responder 276 // 277 278 // data needed for security setup 279 typedef struct sm_setup_context { 280 281 btstack_timer_source_t sm_timeout; 282 283 // used in all phases 284 uint8_t sm_pairing_failed_reason; 285 286 // user response, (Phase 1 and/or 2) 287 uint8_t sm_user_response; 288 uint8_t sm_keypress_notification; 289 290 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 291 int sm_key_distribution_send_set; 292 int sm_key_distribution_received_set; 293 294 // Phase 2 (Pairing over SMP) 295 stk_generation_method_t sm_stk_generation_method; 296 sm_key_t sm_tk; 297 uint8_t sm_use_secure_connections; 298 299 sm_key_t sm_c1_t3_value; // c1 calculation 300 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 301 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 302 sm_key_t sm_local_random; 303 sm_key_t sm_local_confirm; 304 sm_key_t sm_peer_random; 305 sm_key_t sm_peer_confirm; 306 uint8_t sm_m_addr_type; // address and type can be removed 307 uint8_t sm_s_addr_type; // '' 308 bd_addr_t sm_m_address; // '' 309 bd_addr_t sm_s_address; // '' 310 sm_key_t sm_ltk; 311 312 uint8_t sm_state_vars; 313 #ifdef ENABLE_LE_SECURE_CONNECTIONS 314 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 315 uint8_t sm_peer_qy[32]; // '' 316 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 317 sm_key_t sm_local_nonce; // might be combined with sm_local_random 318 sm_key_t sm_peer_dhkey_check; 319 sm_key_t sm_local_dhkey_check; 320 sm_key_t sm_ra; 321 sm_key_t sm_rb; 322 sm_key_t sm_t; // used for f5 and h6 323 sm_key_t sm_mackey; 324 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 325 #endif 326 327 // Phase 3 328 329 // key distribution, we generate 330 uint16_t sm_local_y; 331 uint16_t sm_local_div; 332 uint16_t sm_local_ediv; 333 uint8_t sm_local_rand[8]; 334 sm_key_t sm_local_ltk; 335 sm_key_t sm_local_csrk; 336 sm_key_t sm_local_irk; 337 // sm_local_address/addr_type not needed 338 339 // key distribution, received from peer 340 uint16_t sm_peer_y; 341 uint16_t sm_peer_div; 342 uint16_t sm_peer_ediv; 343 uint8_t sm_peer_rand[8]; 344 sm_key_t sm_peer_ltk; 345 sm_key_t sm_peer_irk; 346 sm_key_t sm_peer_csrk; 347 uint8_t sm_peer_addr_type; 348 bd_addr_t sm_peer_address; 349 350 } sm_setup_context_t; 351 352 // 353 static sm_setup_context_t the_setup; 354 static sm_setup_context_t * setup = &the_setup; 355 356 // active connection - the one for which the_setup is used for 357 static uint16_t sm_active_connection = 0; 358 359 // @returns 1 if oob data is available 360 // stores oob data in provided 16 byte buffer if not null 361 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 362 363 // horizontal: initiator capabilities 364 // vertial: responder capabilities 365 static const stk_generation_method_t stk_generation_method [5] [5] = { 366 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 367 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 368 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 369 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 370 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 371 }; 372 373 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 374 #ifdef ENABLE_LE_SECURE_CONNECTIONS 375 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 376 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 377 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 378 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 379 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 380 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 381 }; 382 #endif 383 384 static void sm_run(void); 385 static void sm_done_for_handle(hci_con_handle_t con_handle); 386 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 387 static inline int sm_calc_actual_encryption_key_size(int other); 388 static int sm_validate_stk_generation_method(void); 389 390 static void log_info_hex16(const char * name, uint16_t value){ 391 log_info("%-6s 0x%04x", name, value); 392 } 393 394 // @returns 1 if all bytes are 0 395 static int sm_is_null(uint8_t * data, int size){ 396 int i; 397 for (i=0; i < size ; i++){ 398 if (data[i]) return 0; 399 } 400 return 1; 401 } 402 403 static int sm_is_null_random(uint8_t random[8]){ 404 return sm_is_null(random, 8); 405 } 406 407 static int sm_is_null_key(uint8_t * key){ 408 return sm_is_null(key, 16); 409 } 410 411 // Key utils 412 static void sm_reset_tk(void){ 413 int i; 414 for (i=0;i<16;i++){ 415 setup->sm_tk[i] = 0; 416 } 417 } 418 419 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 420 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 421 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 422 int i; 423 for (i = max_encryption_size ; i < 16 ; i++){ 424 key[15-i] = 0; 425 } 426 } 427 428 // SMP Timeout implementation 429 430 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 431 // the Security Manager Timer shall be reset and started. 432 // 433 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 434 // 435 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 436 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 437 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 438 // established. 439 440 static void sm_timeout_handler(btstack_timer_source_t * timer){ 441 log_info("SM timeout"); 442 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 443 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 444 sm_done_for_handle(sm_conn->sm_handle); 445 446 // trigger handling of next ready connection 447 sm_run(); 448 } 449 static void sm_timeout_start(sm_connection_t * sm_conn){ 450 btstack_run_loop_remove_timer(&setup->sm_timeout); 451 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 452 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 453 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 454 btstack_run_loop_add_timer(&setup->sm_timeout); 455 } 456 static void sm_timeout_stop(void){ 457 btstack_run_loop_remove_timer(&setup->sm_timeout); 458 } 459 static void sm_timeout_reset(sm_connection_t * sm_conn){ 460 sm_timeout_stop(); 461 sm_timeout_start(sm_conn); 462 } 463 464 // end of sm timeout 465 466 // GAP Random Address updates 467 static gap_random_address_type_t gap_random_adress_type; 468 static btstack_timer_source_t gap_random_address_update_timer; 469 static uint32_t gap_random_adress_update_period; 470 471 static void gap_random_address_trigger(void){ 472 if (rau_state != RAU_IDLE) return; 473 log_info("gap_random_address_trigger"); 474 rau_state = RAU_GET_RANDOM; 475 sm_run(); 476 } 477 478 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 479 UNUSED(timer); 480 481 log_info("GAP Random Address Update due"); 482 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 483 btstack_run_loop_add_timer(&gap_random_address_update_timer); 484 gap_random_address_trigger(); 485 } 486 487 static void gap_random_address_update_start(void){ 488 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 489 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 490 btstack_run_loop_add_timer(&gap_random_address_update_timer); 491 } 492 493 static void gap_random_address_update_stop(void){ 494 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 495 } 496 497 498 static void sm_random_start(void * context){ 499 sm_random_context = context; 500 hci_send_cmd(&hci_le_rand); 501 } 502 503 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 504 // context is made availabe to aes128 result handler by this 505 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 506 sm_aes128_state = SM_AES128_ACTIVE; 507 sm_key_t key_flipped, plaintext_flipped; 508 reverse_128(key, key_flipped); 509 reverse_128(plaintext, plaintext_flipped); 510 sm_aes128_context = context; 511 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 512 } 513 514 // ah(k,r) helper 515 // r = padding || r 516 // r - 24 bit value 517 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 518 // r'= padding || r 519 memset(r_prime, 0, 16); 520 memcpy(&r_prime[13], r, 3); 521 } 522 523 // d1 helper 524 // d' = padding || r || d 525 // d,r - 16 bit values 526 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 527 // d'= padding || r || d 528 memset(d1_prime, 0, 16); 529 big_endian_store_16(d1_prime, 12, r); 530 big_endian_store_16(d1_prime, 14, d); 531 } 532 533 // dm helper 534 // r’ = padding || r 535 // r - 64 bit value 536 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 537 memset(r_prime, 0, 16); 538 memcpy(&r_prime[8], r, 8); 539 } 540 541 // calculate arguments for first AES128 operation in C1 function 542 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 543 544 // p1 = pres || preq || rat’ || iat’ 545 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 546 // cant octet of pres becomes the most significant octet of p1. 547 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 548 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 549 // p1 is 0x05000800000302070710000001010001." 550 551 sm_key_t p1; 552 reverse_56(pres, &p1[0]); 553 reverse_56(preq, &p1[7]); 554 p1[14] = rat; 555 p1[15] = iat; 556 log_info_key("p1", p1); 557 log_info_key("r", r); 558 559 // t1 = r xor p1 560 int i; 561 for (i=0;i<16;i++){ 562 t1[i] = r[i] ^ p1[i]; 563 } 564 log_info_key("t1", t1); 565 } 566 567 // calculate arguments for second AES128 operation in C1 function 568 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 569 // p2 = padding || ia || ra 570 // "The least significant octet of ra becomes the least significant octet of p2 and 571 // the most significant octet of padding becomes the most significant octet of p2. 572 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 573 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 574 575 sm_key_t p2; 576 memset(p2, 0, 16); 577 memcpy(&p2[4], ia, 6); 578 memcpy(&p2[10], ra, 6); 579 log_info_key("p2", p2); 580 581 // c1 = e(k, t2_xor_p2) 582 int i; 583 for (i=0;i<16;i++){ 584 t3[i] = t2[i] ^ p2[i]; 585 } 586 log_info_key("t3", t3); 587 } 588 589 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 590 log_info_key("r1", r1); 591 log_info_key("r2", r2); 592 memcpy(&r_prime[8], &r2[8], 8); 593 memcpy(&r_prime[0], &r1[8], 8); 594 } 595 596 #ifdef ENABLE_LE_SECURE_CONNECTIONS 597 // Software implementations of crypto toolbox for LE Secure Connection 598 // TODO: replace with code to use AES Engine of HCI Controller 599 typedef uint8_t sm_key24_t[3]; 600 typedef uint8_t sm_key56_t[7]; 601 typedef uint8_t sm_key256_t[32]; 602 603 #if 0 604 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 605 uint32_t rk[RKLENGTH(KEYBITS)]; 606 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 607 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 608 } 609 610 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 611 memcpy(k1, k0, 16); 612 sm_shift_left_by_one_bit_inplace(16, k1); 613 if (k0[0] & 0x80){ 614 k1[15] ^= 0x87; 615 } 616 memcpy(k2, k1, 16); 617 sm_shift_left_by_one_bit_inplace(16, k2); 618 if (k1[0] & 0x80){ 619 k2[15] ^= 0x87; 620 } 621 } 622 623 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 624 sm_key_t k0, k1, k2, zero; 625 memset(zero, 0, 16); 626 627 aes128_calc_cyphertext(key, zero, k0); 628 calc_subkeys(k0, k1, k2); 629 630 int cmac_block_count = (cmac_message_len + 15) / 16; 631 632 // step 3: .. 633 if (cmac_block_count==0){ 634 cmac_block_count = 1; 635 } 636 637 // step 4: set m_last 638 sm_key_t cmac_m_last; 639 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 640 int i; 641 if (sm_cmac_last_block_complete){ 642 for (i=0;i<16;i++){ 643 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 644 } 645 } else { 646 int valid_octets_in_last_block = cmac_message_len & 0x0f; 647 for (i=0;i<16;i++){ 648 if (i < valid_octets_in_last_block){ 649 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 650 continue; 651 } 652 if (i == valid_octets_in_last_block){ 653 cmac_m_last[i] = 0x80 ^ k2[i]; 654 continue; 655 } 656 cmac_m_last[i] = k2[i]; 657 } 658 } 659 660 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 661 // LOG_KEY(cmac_m_last); 662 663 // Step 5 664 sm_key_t cmac_x; 665 memset(cmac_x, 0, 16); 666 667 // Step 6 668 sm_key_t sm_cmac_y; 669 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 670 for (i=0;i<16;i++){ 671 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 672 } 673 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 674 } 675 for (i=0;i<16;i++){ 676 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 677 } 678 679 // Step 7 680 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 681 } 682 #endif 683 #endif 684 685 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 686 event[0] = type; 687 event[1] = event_size - 2; 688 little_endian_store_16(event, 2, con_handle); 689 event[4] = addr_type; 690 reverse_bd_addr(address, &event[5]); 691 } 692 693 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 694 UNUSED(channel); 695 696 // log event 697 hci_dump_packet(packet_type, 1, packet, size); 698 // dispatch to all event handlers 699 btstack_linked_list_iterator_t it; 700 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 701 while (btstack_linked_list_iterator_has_next(&it)){ 702 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 703 entry->callback(packet_type, 0, packet, size); 704 } 705 } 706 707 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 708 uint8_t event[11]; 709 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 710 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 711 } 712 713 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 714 uint8_t event[15]; 715 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 716 little_endian_store_32(event, 11, passkey); 717 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 718 } 719 720 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 721 // fetch addr and addr type from db 722 bd_addr_t identity_address; 723 int identity_address_type; 724 le_device_db_info(index, &identity_address_type, identity_address, NULL); 725 726 uint8_t event[19]; 727 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 728 event[11] = identity_address_type; 729 reverse_bd_addr(identity_address, &event[12]); 730 event[18] = index; 731 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 732 } 733 734 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 735 736 uint8_t event[18]; 737 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 738 event[11] = result; 739 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 740 } 741 742 // decide on stk generation based on 743 // - pairing request 744 // - io capabilities 745 // - OOB data availability 746 static void sm_setup_tk(void){ 747 748 // default: just works 749 setup->sm_stk_generation_method = JUST_WORKS; 750 751 #ifdef ENABLE_LE_SECURE_CONNECTIONS 752 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 753 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 754 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 755 memset(setup->sm_ra, 0, 16); 756 memset(setup->sm_rb, 0, 16); 757 #else 758 setup->sm_use_secure_connections = 0; 759 #endif 760 761 // If both devices have not set the MITM option in the Authentication Requirements 762 // Flags, then the IO capabilities shall be ignored and the Just Works association 763 // model shall be used. 764 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 765 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 766 log_info("SM: MITM not required by both -> JUST WORKS"); 767 return; 768 } 769 770 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 771 772 // If both devices have out of band authentication data, then the Authentication 773 // Requirements Flags shall be ignored when selecting the pairing method and the 774 // Out of Band pairing method shall be used. 775 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 776 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 777 log_info("SM: have OOB data"); 778 log_info_key("OOB", setup->sm_tk); 779 setup->sm_stk_generation_method = OOB; 780 return; 781 } 782 783 // Reset TK as it has been setup in sm_init_setup 784 sm_reset_tk(); 785 786 // Also use just works if unknown io capabilites 787 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 788 return; 789 } 790 791 // Otherwise the IO capabilities of the devices shall be used to determine the 792 // pairing method as defined in Table 2.4. 793 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 794 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 795 796 #ifdef ENABLE_LE_SECURE_CONNECTIONS 797 // table not define by default 798 if (setup->sm_use_secure_connections){ 799 generation_method = stk_generation_method_with_secure_connection; 800 } 801 #endif 802 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 803 804 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 805 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 806 } 807 808 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 809 int flags = 0; 810 if (key_set & SM_KEYDIST_ENC_KEY){ 811 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 812 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 813 } 814 if (key_set & SM_KEYDIST_ID_KEY){ 815 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 816 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 817 } 818 if (key_set & SM_KEYDIST_SIGN){ 819 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 820 } 821 return flags; 822 } 823 824 static void sm_setup_key_distribution(uint8_t key_set){ 825 setup->sm_key_distribution_received_set = 0; 826 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 827 } 828 829 // CSRK Key Lookup 830 831 832 static int sm_address_resolution_idle(void){ 833 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 834 } 835 836 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 837 memcpy(sm_address_resolution_address, addr, 6); 838 sm_address_resolution_addr_type = addr_type; 839 sm_address_resolution_test = 0; 840 sm_address_resolution_mode = mode; 841 sm_address_resolution_context = context; 842 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 843 } 844 845 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 846 // check if already in list 847 btstack_linked_list_iterator_t it; 848 sm_lookup_entry_t * entry; 849 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 850 while(btstack_linked_list_iterator_has_next(&it)){ 851 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 852 if (entry->address_type != address_type) continue; 853 if (memcmp(entry->address, address, 6)) continue; 854 // already in list 855 return BTSTACK_BUSY; 856 } 857 entry = btstack_memory_sm_lookup_entry_get(); 858 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 859 entry->address_type = (bd_addr_type_t) address_type; 860 memcpy(entry->address, address, 6); 861 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 862 sm_run(); 863 return 0; 864 } 865 866 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 867 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 868 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 869 } 870 static inline void dkg_next_state(void){ 871 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 872 } 873 static inline void rau_next_state(void){ 874 rau_state = (random_address_update_t) (((int)rau_state) + 1); 875 } 876 877 // CMAC calculation using AES Engine 878 #ifdef ENABLE_CMAC_ENGINE 879 880 static inline void sm_cmac_next_state(void){ 881 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 882 } 883 884 static int sm_cmac_last_block_complete(void){ 885 if (sm_cmac_message_len == 0) return 0; 886 return (sm_cmac_message_len & 0x0f) == 0; 887 } 888 889 int sm_cmac_ready(void){ 890 return sm_cmac_state == CMAC_IDLE; 891 } 892 893 // generic cmac calculation 894 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 895 // Generalized CMAC 896 memcpy(sm_cmac_k, key, 16); 897 memset(sm_cmac_x, 0, 16); 898 sm_cmac_block_current = 0; 899 sm_cmac_message_len = message_len; 900 sm_cmac_done_handler = done_callback; 901 sm_cmac_get_byte = get_byte_callback; 902 903 // step 2: n := ceil(len/const_Bsize); 904 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 905 906 // step 3: .. 907 if (sm_cmac_block_count==0){ 908 sm_cmac_block_count = 1; 909 } 910 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 911 912 // first, we need to compute l for k1, k2, and m_last 913 sm_cmac_state = CMAC_CALC_SUBKEYS; 914 915 // let's go 916 sm_run(); 917 } 918 #endif 919 920 // cmac for ATT Message signing 921 #ifdef ENABLE_LE_SIGNED_WRITE 922 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 923 if (offset >= sm_cmac_message_len) { 924 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 925 return 0; 926 } 927 928 offset = sm_cmac_message_len - 1 - offset; 929 930 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 931 if (offset < 3){ 932 return sm_cmac_header[offset]; 933 } 934 int actual_message_len_incl_header = sm_cmac_message_len - 4; 935 if (offset < actual_message_len_incl_header){ 936 return sm_cmac_message[offset - 3]; 937 } 938 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 939 } 940 941 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 942 // ATT Message Signing 943 sm_cmac_header[0] = opcode; 944 little_endian_store_16(sm_cmac_header, 1, con_handle); 945 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 946 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 947 sm_cmac_message = message; 948 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 949 } 950 #endif 951 952 #ifdef ENABLE_CMAC_ENGINE 953 static void sm_cmac_handle_aes_engine_ready(void){ 954 switch (sm_cmac_state){ 955 case CMAC_CALC_SUBKEYS: { 956 sm_key_t const_zero; 957 memset(const_zero, 0, 16); 958 sm_cmac_next_state(); 959 sm_aes128_start(sm_cmac_k, const_zero, NULL); 960 break; 961 } 962 case CMAC_CALC_MI: { 963 int j; 964 sm_key_t y; 965 for (j=0;j<16;j++){ 966 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 967 } 968 sm_cmac_block_current++; 969 sm_cmac_next_state(); 970 sm_aes128_start(sm_cmac_k, y, NULL); 971 break; 972 } 973 case CMAC_CALC_MLAST: { 974 int i; 975 sm_key_t y; 976 for (i=0;i<16;i++){ 977 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 978 } 979 log_info_key("Y", y); 980 sm_cmac_block_current++; 981 sm_cmac_next_state(); 982 sm_aes128_start(sm_cmac_k, y, NULL); 983 break; 984 } 985 default: 986 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 987 break; 988 } 989 } 990 991 // CMAC Implementation using AES128 engine 992 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 993 int i; 994 int carry = 0; 995 for (i=len-1; i >= 0 ; i--){ 996 int new_carry = data[i] >> 7; 997 data[i] = data[i] << 1 | carry; 998 carry = new_carry; 999 } 1000 } 1001 1002 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1003 switch (sm_cmac_state){ 1004 case CMAC_W4_SUBKEYS: { 1005 sm_key_t k1; 1006 memcpy(k1, data, 16); 1007 sm_shift_left_by_one_bit_inplace(16, k1); 1008 if (data[0] & 0x80){ 1009 k1[15] ^= 0x87; 1010 } 1011 sm_key_t k2; 1012 memcpy(k2, k1, 16); 1013 sm_shift_left_by_one_bit_inplace(16, k2); 1014 if (k1[0] & 0x80){ 1015 k2[15] ^= 0x87; 1016 } 1017 1018 log_info_key("k", sm_cmac_k); 1019 log_info_key("k1", k1); 1020 log_info_key("k2", k2); 1021 1022 // step 4: set m_last 1023 int i; 1024 if (sm_cmac_last_block_complete()){ 1025 for (i=0;i<16;i++){ 1026 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1027 } 1028 } else { 1029 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1030 for (i=0;i<16;i++){ 1031 if (i < valid_octets_in_last_block){ 1032 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1033 continue; 1034 } 1035 if (i == valid_octets_in_last_block){ 1036 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1037 continue; 1038 } 1039 sm_cmac_m_last[i] = k2[i]; 1040 } 1041 } 1042 1043 // next 1044 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1045 break; 1046 } 1047 case CMAC_W4_MI: 1048 memcpy(sm_cmac_x, data, 16); 1049 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1050 break; 1051 case CMAC_W4_MLAST: 1052 // done 1053 log_info("Setting CMAC Engine to IDLE"); 1054 sm_cmac_state = CMAC_IDLE; 1055 log_info_key("CMAC", data); 1056 sm_cmac_done_handler(data); 1057 break; 1058 default: 1059 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1060 break; 1061 } 1062 } 1063 #endif 1064 1065 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1066 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1067 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1068 switch (setup->sm_stk_generation_method){ 1069 case PK_RESP_INPUT: 1070 if (IS_RESPONDER(sm_conn->sm_role)){ 1071 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1072 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1073 } else { 1074 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1075 } 1076 break; 1077 case PK_INIT_INPUT: 1078 if (IS_RESPONDER(sm_conn->sm_role)){ 1079 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1080 } else { 1081 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1082 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1083 } 1084 break; 1085 case OK_BOTH_INPUT: 1086 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1087 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1088 break; 1089 case NK_BOTH_INPUT: 1090 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1091 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1092 break; 1093 case JUST_WORKS: 1094 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1095 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1096 break; 1097 case OOB: 1098 // client already provided OOB data, let's skip notification. 1099 break; 1100 } 1101 } 1102 1103 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1104 int recv_flags; 1105 if (IS_RESPONDER(sm_conn->sm_role)){ 1106 // slave / responder 1107 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1108 } else { 1109 // master / initiator 1110 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1111 } 1112 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1113 return recv_flags == setup->sm_key_distribution_received_set; 1114 } 1115 1116 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1117 if (sm_active_connection == con_handle){ 1118 sm_timeout_stop(); 1119 sm_active_connection = 0; 1120 log_info("sm: connection 0x%x released setup context", con_handle); 1121 } 1122 } 1123 1124 static int sm_key_distribution_flags_for_auth_req(void){ 1125 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1126 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1127 // encryption information only if bonding requested 1128 flags |= SM_KEYDIST_ENC_KEY; 1129 } 1130 return flags; 1131 } 1132 1133 static void sm_reset_setup(void){ 1134 // fill in sm setup 1135 setup->sm_state_vars = 0; 1136 setup->sm_keypress_notification = 0xff; 1137 sm_reset_tk(); 1138 } 1139 1140 static void sm_init_setup(sm_connection_t * sm_conn){ 1141 1142 // fill in sm setup 1143 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1144 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1145 1146 // query client for OOB data 1147 int have_oob_data = 0; 1148 if (sm_get_oob_data) { 1149 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1150 } 1151 1152 sm_pairing_packet_t * local_packet; 1153 if (IS_RESPONDER(sm_conn->sm_role)){ 1154 // slave 1155 local_packet = &setup->sm_s_pres; 1156 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1157 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1158 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1159 } else { 1160 // master 1161 local_packet = &setup->sm_m_preq; 1162 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1163 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1164 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1165 1166 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1167 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1168 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1169 } 1170 1171 uint8_t auth_req = sm_auth_req; 1172 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1173 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1174 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1175 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1176 } 1177 1178 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1179 1180 sm_pairing_packet_t * remote_packet; 1181 int remote_key_request; 1182 if (IS_RESPONDER(sm_conn->sm_role)){ 1183 // slave / responder 1184 remote_packet = &setup->sm_m_preq; 1185 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1186 } else { 1187 // master / initiator 1188 remote_packet = &setup->sm_s_pres; 1189 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1190 } 1191 1192 // check key size 1193 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1194 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1195 1196 // decide on STK generation method 1197 sm_setup_tk(); 1198 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1199 1200 // check if STK generation method is acceptable by client 1201 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1202 1203 // identical to responder 1204 sm_setup_key_distribution(remote_key_request); 1205 1206 // JUST WORKS doens't provide authentication 1207 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1208 1209 return 0; 1210 } 1211 1212 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1213 1214 // cache and reset context 1215 int matched_device_id = sm_address_resolution_test; 1216 address_resolution_mode_t mode = sm_address_resolution_mode; 1217 void * context = sm_address_resolution_context; 1218 1219 // reset context 1220 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1221 sm_address_resolution_context = NULL; 1222 sm_address_resolution_test = -1; 1223 hci_con_handle_t con_handle = 0; 1224 1225 sm_connection_t * sm_connection; 1226 #ifdef ENABLE_LE_CENTRAL 1227 sm_key_t ltk; 1228 #endif 1229 switch (mode){ 1230 case ADDRESS_RESOLUTION_GENERAL: 1231 break; 1232 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1233 sm_connection = (sm_connection_t *) context; 1234 con_handle = sm_connection->sm_handle; 1235 switch (event){ 1236 case ADDRESS_RESOLUTION_SUCEEDED: 1237 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1238 sm_connection->sm_le_db_index = matched_device_id; 1239 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1240 #ifdef ENABLE_LE_CENTRAL 1241 if (sm_connection->sm_role) break; 1242 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1243 sm_connection->sm_security_request_received = 0; 1244 sm_connection->sm_bonding_requested = 0; 1245 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1246 if (!sm_is_null_key(ltk)){ 1247 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1248 } else { 1249 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1250 } 1251 #endif 1252 break; 1253 case ADDRESS_RESOLUTION_FAILED: 1254 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1255 #ifdef ENABLE_LE_CENTRAL 1256 if (sm_connection->sm_role) break; 1257 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1258 sm_connection->sm_security_request_received = 0; 1259 sm_connection->sm_bonding_requested = 0; 1260 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1261 #endif 1262 break; 1263 } 1264 break; 1265 default: 1266 break; 1267 } 1268 1269 switch (event){ 1270 case ADDRESS_RESOLUTION_SUCEEDED: 1271 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1272 break; 1273 case ADDRESS_RESOLUTION_FAILED: 1274 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1275 break; 1276 } 1277 } 1278 1279 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1280 1281 int le_db_index = -1; 1282 1283 // lookup device based on IRK 1284 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1285 int i; 1286 for (i=0; i < le_device_db_count(); i++){ 1287 sm_key_t irk; 1288 bd_addr_t address; 1289 int address_type; 1290 le_device_db_info(i, &address_type, address, irk); 1291 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1292 log_info("sm: device found for IRK, updating"); 1293 le_db_index = i; 1294 break; 1295 } 1296 } 1297 } 1298 1299 // if not found, lookup via public address if possible 1300 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1301 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1302 int i; 1303 for (i=0; i < le_device_db_count(); i++){ 1304 bd_addr_t address; 1305 int address_type; 1306 le_device_db_info(i, &address_type, address, NULL); 1307 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1308 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1309 log_info("sm: device found for public address, updating"); 1310 le_db_index = i; 1311 break; 1312 } 1313 } 1314 } 1315 1316 // if not found, add to db 1317 if (le_db_index < 0) { 1318 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1319 } 1320 1321 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1322 1323 if (le_db_index >= 0){ 1324 1325 #ifdef ENABLE_LE_SIGNED_WRITE 1326 // store local CSRK 1327 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1328 log_info("sm: store local CSRK"); 1329 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1330 le_device_db_local_counter_set(le_db_index, 0); 1331 } 1332 1333 // store remote CSRK 1334 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1335 log_info("sm: store remote CSRK"); 1336 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1337 le_device_db_remote_counter_set(le_db_index, 0); 1338 } 1339 #endif 1340 // store encryption information for secure connections: LTK generated by ECDH 1341 if (setup->sm_use_secure_connections){ 1342 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1343 uint8_t zero_rand[8]; 1344 memset(zero_rand, 0, 8); 1345 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1346 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1347 } 1348 1349 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1350 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1351 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1352 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1353 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1354 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1355 1356 } 1357 } 1358 1359 // keep le_db_index 1360 sm_conn->sm_le_db_index = le_db_index; 1361 } 1362 1363 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1364 setup->sm_pairing_failed_reason = reason; 1365 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1366 } 1367 1368 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1369 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1370 } 1371 1372 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1373 1374 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1375 static int sm_passkey_used(stk_generation_method_t method); 1376 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1377 1378 static void sm_log_ec_keypair(void){ 1379 log_info("Elliptic curve: X"); 1380 log_info_hexdump(ec_qx,32); 1381 log_info("Elliptic curve: Y"); 1382 log_info_hexdump(ec_qy,32); 1383 } 1384 1385 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1386 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1387 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1388 } else { 1389 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1390 } 1391 } 1392 1393 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1394 if (IS_RESPONDER(sm_conn->sm_role)){ 1395 // Responder 1396 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1397 } else { 1398 // Initiator role 1399 switch (setup->sm_stk_generation_method){ 1400 case JUST_WORKS: 1401 sm_sc_prepare_dhkey_check(sm_conn); 1402 break; 1403 1404 case NK_BOTH_INPUT: 1405 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1406 break; 1407 case PK_INIT_INPUT: 1408 case PK_RESP_INPUT: 1409 case OK_BOTH_INPUT: 1410 if (setup->sm_passkey_bit < 20) { 1411 sm_sc_start_calculating_local_confirm(sm_conn); 1412 } else { 1413 sm_sc_prepare_dhkey_check(sm_conn); 1414 } 1415 break; 1416 case OOB: 1417 // TODO: implement SC OOB 1418 break; 1419 } 1420 } 1421 } 1422 1423 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1424 return sm_cmac_sc_buffer[offset]; 1425 } 1426 1427 static void sm_sc_cmac_done(uint8_t * hash){ 1428 log_info("sm_sc_cmac_done: "); 1429 log_info_hexdump(hash, 16); 1430 1431 sm_connection_t * sm_conn = sm_cmac_connection; 1432 sm_cmac_connection = NULL; 1433 link_key_type_t link_key_type; 1434 1435 switch (sm_conn->sm_engine_state){ 1436 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1437 memcpy(setup->sm_local_confirm, hash, 16); 1438 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1439 break; 1440 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1441 // check 1442 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1443 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1444 break; 1445 } 1446 sm_sc_state_after_receiving_random(sm_conn); 1447 break; 1448 case SM_SC_W4_CALCULATE_G2: { 1449 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1450 big_endian_store_32(setup->sm_tk, 12, vab); 1451 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1452 sm_trigger_user_response(sm_conn); 1453 break; 1454 } 1455 case SM_SC_W4_CALCULATE_F5_SALT: 1456 memcpy(setup->sm_t, hash, 16); 1457 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1458 break; 1459 case SM_SC_W4_CALCULATE_F5_MACKEY: 1460 memcpy(setup->sm_mackey, hash, 16); 1461 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1462 break; 1463 case SM_SC_W4_CALCULATE_F5_LTK: 1464 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1465 // Errata Service Release to the Bluetooth Specification: ESR09 1466 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1467 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1468 memcpy(setup->sm_ltk, hash, 16); 1469 memcpy(setup->sm_local_ltk, hash, 16); 1470 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1471 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1472 break; 1473 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1474 memcpy(setup->sm_local_dhkey_check, hash, 16); 1475 if (IS_RESPONDER(sm_conn->sm_role)){ 1476 // responder 1477 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1478 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1479 } else { 1480 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1481 } 1482 } else { 1483 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1484 } 1485 break; 1486 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1487 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1488 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1489 break; 1490 } 1491 if (IS_RESPONDER(sm_conn->sm_role)){ 1492 // responder 1493 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1494 } else { 1495 // initiator 1496 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1497 } 1498 break; 1499 case SM_SC_W4_CALCULATE_H6_ILK: 1500 memcpy(setup->sm_t, hash, 16); 1501 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1502 break; 1503 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1504 reverse_128(hash, setup->sm_t); 1505 link_key_type = sm_conn->sm_connection_authenticated ? 1506 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1507 if (IS_RESPONDER(sm_conn->sm_role)){ 1508 #ifdef ENABLE_CLASSIC 1509 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1510 #endif 1511 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1512 } else { 1513 #ifdef ENABLE_CLASSIC 1514 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1515 #endif 1516 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1517 } 1518 sm_done_for_handle(sm_conn->sm_handle); 1519 break; 1520 default: 1521 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1522 break; 1523 } 1524 sm_run(); 1525 } 1526 1527 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){ 1528 const uint16_t message_len = 65; 1529 sm_cmac_connection = sm_conn; 1530 memcpy(sm_cmac_sc_buffer, u, 32); 1531 memcpy(sm_cmac_sc_buffer+32, v, 32); 1532 sm_cmac_sc_buffer[64] = z; 1533 log_info("f4 key"); 1534 log_info_hexdump(x, 16); 1535 log_info("f4 message"); 1536 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1537 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1538 } 1539 1540 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1541 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1542 static const uint8_t f5_length[] = { 0x01, 0x00}; 1543 1544 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1545 #ifdef USE_MBEDTLS_FOR_ECDH 1546 // da * Pb 1547 mbedtls_mpi d; 1548 mbedtls_ecp_point Q; 1549 mbedtls_ecp_point DH; 1550 mbedtls_mpi_init(&d); 1551 mbedtls_ecp_point_init(&Q); 1552 mbedtls_ecp_point_init(&DH); 1553 mbedtls_mpi_read_binary(&d, ec_d, 32); 1554 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1555 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1556 mbedtls_mpi_lset(&Q.Z, 1); 1557 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1558 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1559 mbedtls_ecp_point_free(&DH); 1560 mbedtls_mpi_free(&d); 1561 mbedtls_ecp_point_free(&Q); 1562 #endif 1563 log_info("dhkey"); 1564 log_info_hexdump(dhkey, 32); 1565 } 1566 1567 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1568 // calculate DHKEY 1569 sm_key256_t dhkey; 1570 sm_sc_calculate_dhkey(dhkey); 1571 1572 // calculate salt for f5 1573 const uint16_t message_len = 32; 1574 sm_cmac_connection = sm_conn; 1575 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1576 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1577 } 1578 1579 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){ 1580 const uint16_t message_len = 53; 1581 sm_cmac_connection = sm_conn; 1582 1583 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1584 sm_cmac_sc_buffer[0] = 0; 1585 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1586 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1587 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1588 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1589 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1590 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1591 log_info("f5 key"); 1592 log_info_hexdump(t, 16); 1593 log_info("f5 message for MacKey"); 1594 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1595 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1596 } 1597 1598 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1599 sm_key56_t bd_addr_master, bd_addr_slave; 1600 bd_addr_master[0] = setup->sm_m_addr_type; 1601 bd_addr_slave[0] = setup->sm_s_addr_type; 1602 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1603 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1604 if (IS_RESPONDER(sm_conn->sm_role)){ 1605 // responder 1606 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1607 } else { 1608 // initiator 1609 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1610 } 1611 } 1612 1613 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1614 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1615 const uint16_t message_len = 53; 1616 sm_cmac_connection = sm_conn; 1617 sm_cmac_sc_buffer[0] = 1; 1618 // 1..52 setup before 1619 log_info("f5 key"); 1620 log_info_hexdump(t, 16); 1621 log_info("f5 message for LTK"); 1622 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1623 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1624 } 1625 1626 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1627 f5_ltk(sm_conn, setup->sm_t); 1628 } 1629 1630 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){ 1631 const uint16_t message_len = 65; 1632 sm_cmac_connection = sm_conn; 1633 memcpy(sm_cmac_sc_buffer, n1, 16); 1634 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1635 memcpy(sm_cmac_sc_buffer+32, r, 16); 1636 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1637 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1638 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1639 log_info("f6 key"); 1640 log_info_hexdump(w, 16); 1641 log_info("f6 message"); 1642 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1643 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1644 } 1645 1646 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1647 // - U is 256 bits 1648 // - V is 256 bits 1649 // - X is 128 bits 1650 // - Y is 128 bits 1651 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){ 1652 const uint16_t message_len = 80; 1653 sm_cmac_connection = sm_conn; 1654 memcpy(sm_cmac_sc_buffer, u, 32); 1655 memcpy(sm_cmac_sc_buffer+32, v, 32); 1656 memcpy(sm_cmac_sc_buffer+64, y, 16); 1657 log_info("g2 key"); 1658 log_info_hexdump(x, 16); 1659 log_info("g2 message"); 1660 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1661 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1662 } 1663 1664 static void g2_calculate(sm_connection_t * sm_conn) { 1665 // calc Va if numeric comparison 1666 if (IS_RESPONDER(sm_conn->sm_role)){ 1667 // responder 1668 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1669 } else { 1670 // initiator 1671 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1672 } 1673 } 1674 1675 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1676 uint8_t z = 0; 1677 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1678 // some form of passkey 1679 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1680 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1681 setup->sm_passkey_bit++; 1682 } 1683 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1684 } 1685 1686 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1687 uint8_t z = 0; 1688 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1689 // some form of passkey 1690 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1691 // sm_passkey_bit was increased before sending confirm value 1692 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1693 } 1694 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1695 } 1696 1697 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1698 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1699 } 1700 1701 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1702 // calculate DHKCheck 1703 sm_key56_t bd_addr_master, bd_addr_slave; 1704 bd_addr_master[0] = setup->sm_m_addr_type; 1705 bd_addr_slave[0] = setup->sm_s_addr_type; 1706 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1707 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1708 uint8_t iocap_a[3]; 1709 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1710 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1711 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1712 uint8_t iocap_b[3]; 1713 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1714 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1715 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1716 if (IS_RESPONDER(sm_conn->sm_role)){ 1717 // responder 1718 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); 1719 } else { 1720 // initiator 1721 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); 1722 } 1723 } 1724 1725 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1726 // validate E = f6() 1727 sm_key56_t bd_addr_master, bd_addr_slave; 1728 bd_addr_master[0] = setup->sm_m_addr_type; 1729 bd_addr_slave[0] = setup->sm_s_addr_type; 1730 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1731 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1732 1733 uint8_t iocap_a[3]; 1734 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1735 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1736 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1737 uint8_t iocap_b[3]; 1738 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1739 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1740 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1741 if (IS_RESPONDER(sm_conn->sm_role)){ 1742 // responder 1743 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); 1744 } else { 1745 // initiator 1746 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); 1747 } 1748 } 1749 1750 1751 // 1752 // Link Key Conversion Function h6 1753 // 1754 // h6(W, keyID) = AES-CMACW(keyID) 1755 // - W is 128 bits 1756 // - keyID is 32 bits 1757 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1758 const uint16_t message_len = 4; 1759 sm_cmac_connection = sm_conn; 1760 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1761 log_info("h6 key"); 1762 log_info_hexdump(w, 16); 1763 log_info("h6 message"); 1764 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1765 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1766 } 1767 1768 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1769 // Errata Service Release to the Bluetooth Specification: ESR09 1770 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1771 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1772 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1773 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1774 } 1775 1776 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1777 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1778 } 1779 1780 #endif 1781 1782 // key management legacy connections: 1783 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1784 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1785 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1786 // - responder reconnects: responder uses LTK receveived from master 1787 1788 // key management secure connections: 1789 // - both devices store same LTK from ECDH key exchange. 1790 1791 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1792 static void sm_load_security_info(sm_connection_t * sm_connection){ 1793 int encryption_key_size; 1794 int authenticated; 1795 int authorized; 1796 1797 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1798 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1799 &encryption_key_size, &authenticated, &authorized); 1800 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1801 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1802 sm_connection->sm_connection_authenticated = authenticated; 1803 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1804 } 1805 #endif 1806 1807 #ifdef ENABLE_LE_PERIPHERAL 1808 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1809 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1810 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1811 // re-establish used key encryption size 1812 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1813 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1814 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1815 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1816 log_info("sm: received ltk request with key size %u, authenticated %u", 1817 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1818 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1819 } 1820 #endif 1821 1822 static void sm_run(void){ 1823 1824 btstack_linked_list_iterator_t it; 1825 1826 // assert that we can send at least commands 1827 if (!hci_can_send_command_packet_now()) return; 1828 1829 // 1830 // non-connection related behaviour 1831 // 1832 1833 // distributed key generation 1834 switch (dkg_state){ 1835 case DKG_CALC_IRK: 1836 // already busy? 1837 if (sm_aes128_state == SM_AES128_IDLE) { 1838 // IRK = d1(IR, 1, 0) 1839 sm_key_t d1_prime; 1840 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1841 dkg_next_state(); 1842 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1843 return; 1844 } 1845 break; 1846 case DKG_CALC_DHK: 1847 // already busy? 1848 if (sm_aes128_state == SM_AES128_IDLE) { 1849 // DHK = d1(IR, 3, 0) 1850 sm_key_t d1_prime; 1851 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1852 dkg_next_state(); 1853 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1854 return; 1855 } 1856 break; 1857 default: 1858 break; 1859 } 1860 1861 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1862 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1863 #ifdef USE_MBEDTLS_FOR_ECDH 1864 sm_random_start(NULL); 1865 #else 1866 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1867 hci_send_cmd(&hci_le_read_local_p256_public_key); 1868 #endif 1869 return; 1870 } 1871 #endif 1872 1873 // random address updates 1874 switch (rau_state){ 1875 case RAU_GET_RANDOM: 1876 rau_next_state(); 1877 sm_random_start(NULL); 1878 return; 1879 case RAU_GET_ENC: 1880 // already busy? 1881 if (sm_aes128_state == SM_AES128_IDLE) { 1882 sm_key_t r_prime; 1883 sm_ah_r_prime(sm_random_address, r_prime); 1884 rau_next_state(); 1885 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1886 return; 1887 } 1888 break; 1889 case RAU_SET_ADDRESS: 1890 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1891 rau_state = RAU_IDLE; 1892 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1893 return; 1894 default: 1895 break; 1896 } 1897 1898 #ifdef ENABLE_CMAC_ENGINE 1899 // CMAC 1900 switch (sm_cmac_state){ 1901 case CMAC_CALC_SUBKEYS: 1902 case CMAC_CALC_MI: 1903 case CMAC_CALC_MLAST: 1904 // already busy? 1905 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1906 sm_cmac_handle_aes_engine_ready(); 1907 return; 1908 default: 1909 break; 1910 } 1911 #endif 1912 1913 // CSRK Lookup 1914 // -- if csrk lookup ready, find connection that require csrk lookup 1915 if (sm_address_resolution_idle()){ 1916 hci_connections_get_iterator(&it); 1917 while(btstack_linked_list_iterator_has_next(&it)){ 1918 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1919 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1920 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1921 // and start lookup 1922 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); 1923 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1924 break; 1925 } 1926 } 1927 } 1928 1929 // -- if csrk lookup ready, resolved addresses for received addresses 1930 if (sm_address_resolution_idle()) { 1931 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1932 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1933 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1934 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1935 btstack_memory_sm_lookup_entry_free(entry); 1936 } 1937 } 1938 1939 // -- Continue with CSRK device lookup by public or resolvable private address 1940 if (!sm_address_resolution_idle()){ 1941 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1942 while (sm_address_resolution_test < le_device_db_count()){ 1943 int addr_type; 1944 bd_addr_t addr; 1945 sm_key_t irk; 1946 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1947 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1948 1949 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1950 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1951 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1952 break; 1953 } 1954 1955 if (sm_address_resolution_addr_type == 0){ 1956 sm_address_resolution_test++; 1957 continue; 1958 } 1959 1960 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1961 1962 log_info("LE Device Lookup: calculate AH"); 1963 log_info_key("IRK", irk); 1964 1965 sm_key_t r_prime; 1966 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1967 sm_address_resolution_ah_calculation_active = 1; 1968 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1969 return; 1970 } 1971 1972 if (sm_address_resolution_test >= le_device_db_count()){ 1973 log_info("LE Device Lookup: not found"); 1974 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1975 } 1976 } 1977 1978 // handle basic actions that don't requires the full context 1979 hci_connections_get_iterator(&it); 1980 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1981 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1982 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1983 switch(sm_connection->sm_engine_state){ 1984 // responder side 1985 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1986 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1987 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1988 return; 1989 1990 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1991 case SM_SC_RECEIVED_LTK_REQUEST: 1992 switch (sm_connection->sm_irk_lookup_state){ 1993 case IRK_LOOKUP_FAILED: 1994 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1995 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1996 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1997 return; 1998 default: 1999 break; 2000 } 2001 break; 2002 #endif 2003 default: 2004 break; 2005 } 2006 } 2007 2008 // 2009 // active connection handling 2010 // -- use loop to handle next connection if lock on setup context is released 2011 2012 while (1) { 2013 2014 // Find connections that requires setup context and make active if no other is locked 2015 hci_connections_get_iterator(&it); 2016 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 2017 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2018 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2019 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2020 int done = 1; 2021 int err; 2022 UNUSED(err); 2023 switch (sm_connection->sm_engine_state) { 2024 #ifdef ENABLE_LE_PERIPHERAL 2025 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2026 // send packet if possible, 2027 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2028 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2029 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2030 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2031 } else { 2032 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2033 } 2034 // don't lock sxetup context yet 2035 done = 0; 2036 break; 2037 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2038 sm_reset_setup(); 2039 sm_init_setup(sm_connection); 2040 // recover pairing request 2041 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2042 err = sm_stk_generation_init(sm_connection); 2043 if (err){ 2044 setup->sm_pairing_failed_reason = err; 2045 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2046 break; 2047 } 2048 sm_timeout_start(sm_connection); 2049 // generate random number first, if we need to show passkey 2050 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2051 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2052 break; 2053 } 2054 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2055 break; 2056 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2057 sm_reset_setup(); 2058 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2059 break; 2060 #endif 2061 #ifdef ENABLE_LE_CENTRAL 2062 case SM_INITIATOR_PH0_HAS_LTK: 2063 sm_reset_setup(); 2064 sm_load_security_info(sm_connection); 2065 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2066 break; 2067 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2068 sm_reset_setup(); 2069 sm_init_setup(sm_connection); 2070 sm_timeout_start(sm_connection); 2071 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2072 break; 2073 #endif 2074 2075 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2076 case SM_SC_RECEIVED_LTK_REQUEST: 2077 switch (sm_connection->sm_irk_lookup_state){ 2078 case IRK_LOOKUP_SUCCEEDED: 2079 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2080 // start using context by loading security info 2081 sm_reset_setup(); 2082 sm_load_security_info(sm_connection); 2083 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2084 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2085 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2086 break; 2087 } 2088 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2089 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2090 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2091 // don't lock setup context yet 2092 return; 2093 default: 2094 // just wait until IRK lookup is completed 2095 // don't lock setup context yet 2096 done = 0; 2097 break; 2098 } 2099 break; 2100 #endif 2101 default: 2102 done = 0; 2103 break; 2104 } 2105 if (done){ 2106 sm_active_connection = sm_connection->sm_handle; 2107 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2108 } 2109 } 2110 2111 // 2112 // active connection handling 2113 // 2114 2115 if (sm_active_connection == 0) return; 2116 2117 // assert that we could send a SM PDU - not needed for all of the following 2118 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2119 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2120 return; 2121 } 2122 2123 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2124 if (!connection) return; 2125 2126 // send keypress notifications 2127 if (setup->sm_keypress_notification != 0xff){ 2128 uint8_t buffer[2]; 2129 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2130 buffer[1] = setup->sm_keypress_notification; 2131 setup->sm_keypress_notification = 0xff; 2132 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2133 return; 2134 } 2135 2136 sm_key_t plaintext; 2137 int key_distribution_flags; 2138 UNUSED(key_distribution_flags); 2139 2140 log_info("sm_run: state %u", connection->sm_engine_state); 2141 2142 switch (connection->sm_engine_state){ 2143 2144 // general 2145 case SM_GENERAL_SEND_PAIRING_FAILED: { 2146 uint8_t buffer[2]; 2147 buffer[0] = SM_CODE_PAIRING_FAILED; 2148 buffer[1] = setup->sm_pairing_failed_reason; 2149 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2150 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2151 sm_done_for_handle(connection->sm_handle); 2152 break; 2153 } 2154 2155 // responding state 2156 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2157 case SM_SC_W2_GET_RANDOM_A: 2158 sm_random_start(connection); 2159 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2160 break; 2161 case SM_SC_W2_GET_RANDOM_B: 2162 sm_random_start(connection); 2163 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2164 break; 2165 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2166 if (!sm_cmac_ready()) break; 2167 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2168 sm_sc_calculate_local_confirm(connection); 2169 break; 2170 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2171 if (!sm_cmac_ready()) break; 2172 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2173 sm_sc_calculate_remote_confirm(connection); 2174 break; 2175 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2176 if (!sm_cmac_ready()) break; 2177 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2178 sm_sc_calculate_f6_for_dhkey_check(connection); 2179 break; 2180 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2181 if (!sm_cmac_ready()) break; 2182 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2183 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2184 break; 2185 case SM_SC_W2_CALCULATE_F5_SALT: 2186 if (!sm_cmac_ready()) break; 2187 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2188 f5_calculate_salt(connection); 2189 break; 2190 case SM_SC_W2_CALCULATE_F5_MACKEY: 2191 if (!sm_cmac_ready()) break; 2192 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2193 f5_calculate_mackey(connection); 2194 break; 2195 case SM_SC_W2_CALCULATE_F5_LTK: 2196 if (!sm_cmac_ready()) break; 2197 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2198 f5_calculate_ltk(connection); 2199 break; 2200 case SM_SC_W2_CALCULATE_G2: 2201 if (!sm_cmac_ready()) break; 2202 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2203 g2_calculate(connection); 2204 break; 2205 case SM_SC_W2_CALCULATE_H6_ILK: 2206 if (!sm_cmac_ready()) break; 2207 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2208 h6_calculate_ilk(connection); 2209 break; 2210 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2211 if (!sm_cmac_ready()) break; 2212 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2213 h6_calculate_br_edr_link_key(connection); 2214 break; 2215 #endif 2216 2217 #ifdef ENABLE_LE_CENTRAL 2218 // initiator side 2219 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2220 sm_key_t peer_ltk_flipped; 2221 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2222 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2223 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2224 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2225 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2226 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2227 return; 2228 } 2229 2230 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2231 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2232 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2233 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2234 sm_timeout_reset(connection); 2235 break; 2236 #endif 2237 2238 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2239 2240 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2241 uint8_t buffer[65]; 2242 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2243 // 2244 reverse_256(ec_qx, &buffer[1]); 2245 reverse_256(ec_qy, &buffer[33]); 2246 2247 // stk generation method 2248 // passkey entry: notify app to show passkey or to request passkey 2249 switch (setup->sm_stk_generation_method){ 2250 case JUST_WORKS: 2251 case NK_BOTH_INPUT: 2252 if (IS_RESPONDER(connection->sm_role)){ 2253 // responder 2254 sm_sc_start_calculating_local_confirm(connection); 2255 } else { 2256 // initiator 2257 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2258 } 2259 break; 2260 case PK_INIT_INPUT: 2261 case PK_RESP_INPUT: 2262 case OK_BOTH_INPUT: 2263 // use random TK for display 2264 memcpy(setup->sm_ra, setup->sm_tk, 16); 2265 memcpy(setup->sm_rb, setup->sm_tk, 16); 2266 setup->sm_passkey_bit = 0; 2267 2268 if (IS_RESPONDER(connection->sm_role)){ 2269 // responder 2270 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2271 } else { 2272 // initiator 2273 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2274 } 2275 sm_trigger_user_response(connection); 2276 break; 2277 case OOB: 2278 // TODO: implement SC OOB 2279 break; 2280 } 2281 2282 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2283 sm_timeout_reset(connection); 2284 break; 2285 } 2286 case SM_SC_SEND_CONFIRMATION: { 2287 uint8_t buffer[17]; 2288 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2289 reverse_128(setup->sm_local_confirm, &buffer[1]); 2290 if (IS_RESPONDER(connection->sm_role)){ 2291 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2292 } else { 2293 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2294 } 2295 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2296 sm_timeout_reset(connection); 2297 break; 2298 } 2299 case SM_SC_SEND_PAIRING_RANDOM: { 2300 uint8_t buffer[17]; 2301 buffer[0] = SM_CODE_PAIRING_RANDOM; 2302 reverse_128(setup->sm_local_nonce, &buffer[1]); 2303 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2304 if (IS_RESPONDER(connection->sm_role)){ 2305 // responder 2306 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2307 } else { 2308 // initiator 2309 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2310 } 2311 } else { 2312 if (IS_RESPONDER(connection->sm_role)){ 2313 // responder 2314 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2315 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2316 } else { 2317 sm_sc_prepare_dhkey_check(connection); 2318 } 2319 } else { 2320 // initiator 2321 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2322 } 2323 } 2324 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2325 sm_timeout_reset(connection); 2326 break; 2327 } 2328 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2329 uint8_t buffer[17]; 2330 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2331 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2332 2333 if (IS_RESPONDER(connection->sm_role)){ 2334 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2335 } else { 2336 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2337 } 2338 2339 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2340 sm_timeout_reset(connection); 2341 break; 2342 } 2343 2344 #endif 2345 2346 #ifdef ENABLE_LE_PERIPHERAL 2347 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2348 // echo initiator for now 2349 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2350 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2351 2352 if (setup->sm_use_secure_connections){ 2353 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2354 // skip LTK/EDIV for SC 2355 log_info("sm: dropping encryption information flag"); 2356 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2357 } else { 2358 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2359 } 2360 2361 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); 2362 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); 2363 // update key distribution after ENC was dropped 2364 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2365 2366 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2367 sm_timeout_reset(connection); 2368 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2369 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2370 sm_trigger_user_response(connection); 2371 } 2372 return; 2373 #endif 2374 2375 case SM_PH2_SEND_PAIRING_RANDOM: { 2376 uint8_t buffer[17]; 2377 buffer[0] = SM_CODE_PAIRING_RANDOM; 2378 reverse_128(setup->sm_local_random, &buffer[1]); 2379 if (IS_RESPONDER(connection->sm_role)){ 2380 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2381 } else { 2382 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2383 } 2384 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2385 sm_timeout_reset(connection); 2386 break; 2387 } 2388 2389 case SM_PH2_GET_RANDOM_TK: 2390 case SM_PH2_C1_GET_RANDOM_A: 2391 case SM_PH2_C1_GET_RANDOM_B: 2392 case SM_PH3_GET_RANDOM: 2393 case SM_PH3_GET_DIV: 2394 sm_next_responding_state(connection); 2395 sm_random_start(connection); 2396 return; 2397 2398 case SM_PH2_C1_GET_ENC_B: 2399 case SM_PH2_C1_GET_ENC_D: 2400 // already busy? 2401 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2402 sm_next_responding_state(connection); 2403 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2404 return; 2405 2406 case SM_PH3_LTK_GET_ENC: 2407 case SM_RESPONDER_PH4_LTK_GET_ENC: 2408 // already busy? 2409 if (sm_aes128_state == SM_AES128_IDLE) { 2410 sm_key_t d_prime; 2411 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2412 sm_next_responding_state(connection); 2413 sm_aes128_start(sm_persistent_er, d_prime, connection); 2414 return; 2415 } 2416 break; 2417 2418 case SM_PH3_CSRK_GET_ENC: 2419 // already busy? 2420 if (sm_aes128_state == SM_AES128_IDLE) { 2421 sm_key_t d_prime; 2422 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2423 sm_next_responding_state(connection); 2424 sm_aes128_start(sm_persistent_er, d_prime, connection); 2425 return; 2426 } 2427 break; 2428 2429 case SM_PH2_C1_GET_ENC_C: 2430 // already busy? 2431 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2432 // calculate m_confirm using aes128 engine - step 1 2433 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); 2434 sm_next_responding_state(connection); 2435 sm_aes128_start(setup->sm_tk, plaintext, connection); 2436 break; 2437 case SM_PH2_C1_GET_ENC_A: 2438 // already busy? 2439 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2440 // calculate confirm using aes128 engine - step 1 2441 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); 2442 sm_next_responding_state(connection); 2443 sm_aes128_start(setup->sm_tk, plaintext, connection); 2444 break; 2445 case SM_PH2_CALC_STK: 2446 // already busy? 2447 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2448 // calculate STK 2449 if (IS_RESPONDER(connection->sm_role)){ 2450 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2451 } else { 2452 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2453 } 2454 sm_next_responding_state(connection); 2455 sm_aes128_start(setup->sm_tk, plaintext, connection); 2456 break; 2457 case SM_PH3_Y_GET_ENC: 2458 // already busy? 2459 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2460 // PH3B2 - calculate Y from - enc 2461 // Y = dm(DHK, Rand) 2462 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2463 sm_next_responding_state(connection); 2464 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2465 return; 2466 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2467 uint8_t buffer[17]; 2468 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2469 reverse_128(setup->sm_local_confirm, &buffer[1]); 2470 if (IS_RESPONDER(connection->sm_role)){ 2471 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2472 } else { 2473 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2474 } 2475 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2476 sm_timeout_reset(connection); 2477 return; 2478 } 2479 #ifdef ENABLE_LE_PERIPHERAL 2480 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2481 sm_key_t stk_flipped; 2482 reverse_128(setup->sm_ltk, stk_flipped); 2483 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2484 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2485 return; 2486 } 2487 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2488 sm_key_t ltk_flipped; 2489 reverse_128(setup->sm_ltk, ltk_flipped); 2490 connection->sm_engine_state = SM_RESPONDER_IDLE; 2491 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2492 return; 2493 } 2494 case SM_RESPONDER_PH4_Y_GET_ENC: 2495 // already busy? 2496 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2497 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2498 // Y = dm(DHK, Rand) 2499 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2500 sm_next_responding_state(connection); 2501 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2502 return; 2503 #endif 2504 #ifdef ENABLE_LE_CENTRAL 2505 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2506 sm_key_t stk_flipped; 2507 reverse_128(setup->sm_ltk, stk_flipped); 2508 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2509 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2510 return; 2511 } 2512 #endif 2513 2514 case SM_PH3_DISTRIBUTE_KEYS: 2515 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2516 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2517 uint8_t buffer[17]; 2518 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2519 reverse_128(setup->sm_ltk, &buffer[1]); 2520 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2521 sm_timeout_reset(connection); 2522 return; 2523 } 2524 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2525 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2526 uint8_t buffer[11]; 2527 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2528 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2529 reverse_64(setup->sm_local_rand, &buffer[3]); 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_IDENTITY_INFORMATION){ 2535 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2536 uint8_t buffer[17]; 2537 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2538 reverse_128(sm_persistent_irk, &buffer[1]); 2539 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2540 sm_timeout_reset(connection); 2541 return; 2542 } 2543 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2544 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2545 bd_addr_t local_address; 2546 uint8_t buffer[8]; 2547 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2548 gap_le_get_own_address(&buffer[1], local_address); 2549 reverse_bd_addr(local_address, &buffer[2]); 2550 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2551 sm_timeout_reset(connection); 2552 return; 2553 } 2554 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2555 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2556 2557 // hack to reproduce test runs 2558 if (test_use_fixed_local_csrk){ 2559 memset(setup->sm_local_csrk, 0xcc, 16); 2560 } 2561 2562 uint8_t buffer[17]; 2563 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2564 reverse_128(setup->sm_local_csrk, &buffer[1]); 2565 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2566 sm_timeout_reset(connection); 2567 return; 2568 } 2569 2570 // keys are sent 2571 if (IS_RESPONDER(connection->sm_role)){ 2572 // slave -> receive master keys if any 2573 if (sm_key_distribution_all_received(connection)){ 2574 sm_key_distribution_handle_all_received(connection); 2575 connection->sm_engine_state = SM_RESPONDER_IDLE; 2576 sm_done_for_handle(connection->sm_handle); 2577 } else { 2578 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2579 } 2580 } else { 2581 // master -> all done 2582 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2583 sm_done_for_handle(connection->sm_handle); 2584 } 2585 break; 2586 2587 default: 2588 break; 2589 } 2590 2591 // check again if active connection was released 2592 if (sm_active_connection) break; 2593 } 2594 } 2595 2596 // note: aes engine is ready as we just got the aes result 2597 static void sm_handle_encryption_result(uint8_t * data){ 2598 2599 sm_aes128_state = SM_AES128_IDLE; 2600 2601 if (sm_address_resolution_ah_calculation_active){ 2602 sm_address_resolution_ah_calculation_active = 0; 2603 // compare calulated address against connecting device 2604 uint8_t hash[3]; 2605 reverse_24(data, hash); 2606 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2607 log_info("LE Device Lookup: matched resolvable private address"); 2608 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2609 return; 2610 } 2611 // no match, try next 2612 sm_address_resolution_test++; 2613 return; 2614 } 2615 2616 switch (dkg_state){ 2617 case DKG_W4_IRK: 2618 reverse_128(data, sm_persistent_irk); 2619 log_info_key("irk", sm_persistent_irk); 2620 dkg_next_state(); 2621 return; 2622 case DKG_W4_DHK: 2623 reverse_128(data, sm_persistent_dhk); 2624 log_info_key("dhk", sm_persistent_dhk); 2625 dkg_next_state(); 2626 // SM Init Finished 2627 return; 2628 default: 2629 break; 2630 } 2631 2632 switch (rau_state){ 2633 case RAU_W4_ENC: 2634 reverse_24(data, &sm_random_address[3]); 2635 rau_next_state(); 2636 return; 2637 default: 2638 break; 2639 } 2640 2641 #ifdef ENABLE_CMAC_ENGINE 2642 switch (sm_cmac_state){ 2643 case CMAC_W4_SUBKEYS: 2644 case CMAC_W4_MI: 2645 case CMAC_W4_MLAST: 2646 { 2647 sm_key_t t; 2648 reverse_128(data, t); 2649 sm_cmac_handle_encryption_result(t); 2650 } 2651 return; 2652 default: 2653 break; 2654 } 2655 #endif 2656 2657 // retrieve sm_connection provided to sm_aes128_start_encryption 2658 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2659 if (!connection) return; 2660 switch (connection->sm_engine_state){ 2661 case SM_PH2_C1_W4_ENC_A: 2662 case SM_PH2_C1_W4_ENC_C: 2663 { 2664 sm_key_t t2; 2665 reverse_128(data, t2); 2666 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2667 } 2668 sm_next_responding_state(connection); 2669 return; 2670 case SM_PH2_C1_W4_ENC_B: 2671 reverse_128(data, setup->sm_local_confirm); 2672 log_info_key("c1!", setup->sm_local_confirm); 2673 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2674 return; 2675 case SM_PH2_C1_W4_ENC_D: 2676 { 2677 sm_key_t peer_confirm_test; 2678 reverse_128(data, peer_confirm_test); 2679 log_info_key("c1!", peer_confirm_test); 2680 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2681 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2682 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2683 return; 2684 } 2685 if (IS_RESPONDER(connection->sm_role)){ 2686 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2687 } else { 2688 connection->sm_engine_state = SM_PH2_CALC_STK; 2689 } 2690 } 2691 return; 2692 case SM_PH2_W4_STK: 2693 reverse_128(data, setup->sm_ltk); 2694 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2695 log_info_key("stk", setup->sm_ltk); 2696 if (IS_RESPONDER(connection->sm_role)){ 2697 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2698 } else { 2699 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2700 } 2701 return; 2702 case SM_PH3_Y_W4_ENC:{ 2703 sm_key_t y128; 2704 reverse_128(data, y128); 2705 setup->sm_local_y = big_endian_read_16(y128, 14); 2706 log_info_hex16("y", setup->sm_local_y); 2707 // PH3B3 - calculate EDIV 2708 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2709 log_info_hex16("ediv", setup->sm_local_ediv); 2710 // PH3B4 - calculate LTK - enc 2711 // LTK = d1(ER, DIV, 0)) 2712 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2713 return; 2714 } 2715 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2716 sm_key_t y128; 2717 reverse_128(data, y128); 2718 setup->sm_local_y = big_endian_read_16(y128, 14); 2719 log_info_hex16("y", setup->sm_local_y); 2720 2721 // PH3B3 - calculate DIV 2722 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2723 log_info_hex16("ediv", setup->sm_local_ediv); 2724 // PH3B4 - calculate LTK - enc 2725 // LTK = d1(ER, DIV, 0)) 2726 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2727 return; 2728 } 2729 case SM_PH3_LTK_W4_ENC: 2730 reverse_128(data, setup->sm_ltk); 2731 log_info_key("ltk", setup->sm_ltk); 2732 // calc CSRK next 2733 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2734 return; 2735 case SM_PH3_CSRK_W4_ENC: 2736 reverse_128(data, setup->sm_local_csrk); 2737 log_info_key("csrk", setup->sm_local_csrk); 2738 if (setup->sm_key_distribution_send_set){ 2739 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2740 } else { 2741 // no keys to send, just continue 2742 if (IS_RESPONDER(connection->sm_role)){ 2743 // slave -> receive master keys 2744 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2745 } else { 2746 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2747 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2748 } else { 2749 // master -> all done 2750 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2751 sm_done_for_handle(connection->sm_handle); 2752 } 2753 } 2754 } 2755 return; 2756 #ifdef ENABLE_LE_PERIPHERAL 2757 case SM_RESPONDER_PH4_LTK_W4_ENC: 2758 reverse_128(data, setup->sm_ltk); 2759 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2760 log_info_key("ltk", setup->sm_ltk); 2761 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2762 return; 2763 #endif 2764 default: 2765 break; 2766 } 2767 } 2768 2769 #ifdef USE_MBEDTLS_FOR_ECDH 2770 2771 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2772 UNUSED(context); 2773 2774 int offset = setup->sm_passkey_bit; 2775 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2776 while (size) { 2777 if (offset < 32){ 2778 *buffer++ = setup->sm_peer_qx[offset++]; 2779 } else { 2780 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2781 } 2782 size--; 2783 } 2784 setup->sm_passkey_bit = offset; 2785 return 0; 2786 } 2787 #endif 2788 2789 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2790 static void sm_handle_random_result(uint8_t * data){ 2791 2792 #ifdef USE_MBEDTLS_FOR_ECDH 2793 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2794 int num_bytes = setup->sm_passkey_bit; 2795 if (num_bytes < 32){ 2796 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2797 } else { 2798 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2799 } 2800 num_bytes += 8; 2801 setup->sm_passkey_bit = num_bytes; 2802 2803 if (num_bytes >= 64){ 2804 2805 // generate EC key 2806 setup->sm_passkey_bit = 0; 2807 mbedtls_mpi d; 2808 mbedtls_ecp_point P; 2809 mbedtls_mpi_init(&d); 2810 mbedtls_ecp_point_init(&P); 2811 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2812 log_info("gen keypair %x", res); 2813 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2814 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2815 mbedtls_mpi_write_binary(&d, ec_d, 32); 2816 mbedtls_ecp_point_free(&P); 2817 mbedtls_mpi_free(&d); 2818 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2819 log_info("Elliptic curve: d"); 2820 log_info_hexdump(ec_d,32); 2821 sm_log_ec_keypair(); 2822 2823 #if 0 2824 int i; 2825 sm_key256_t dhkey; 2826 for (i=0;i<10;i++){ 2827 // printf("test dhkey check\n"); 2828 memcpy(setup->sm_peer_qx, ec_qx, 32); 2829 memcpy(setup->sm_peer_qy, ec_qy, 32); 2830 sm_sc_calculate_dhkey(dhkey); 2831 // printf("test dhkey check end\n"); 2832 } 2833 #endif 2834 2835 } 2836 } 2837 #endif 2838 2839 switch (rau_state){ 2840 case RAU_W4_RANDOM: 2841 // non-resolvable vs. resolvable 2842 switch (gap_random_adress_type){ 2843 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2844 // resolvable: use random as prand and calc address hash 2845 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2846 memcpy(sm_random_address, data, 3); 2847 sm_random_address[0] &= 0x3f; 2848 sm_random_address[0] |= 0x40; 2849 rau_state = RAU_GET_ENC; 2850 break; 2851 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2852 default: 2853 // "The two most significant bits of the address shall be equal to ‘0’"" 2854 memcpy(sm_random_address, data, 6); 2855 sm_random_address[0] &= 0x3f; 2856 rau_state = RAU_SET_ADDRESS; 2857 break; 2858 } 2859 return; 2860 default: 2861 break; 2862 } 2863 2864 // retrieve sm_connection provided to sm_random_start 2865 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2866 if (!connection) return; 2867 switch (connection->sm_engine_state){ 2868 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2869 case SM_SC_W4_GET_RANDOM_A: 2870 memcpy(&setup->sm_local_nonce[0], data, 8); 2871 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2872 break; 2873 case SM_SC_W4_GET_RANDOM_B: 2874 memcpy(&setup->sm_local_nonce[8], data, 8); 2875 // initiator & jw/nc -> send pairing random 2876 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2877 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2878 break; 2879 } else { 2880 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2881 } 2882 break; 2883 #endif 2884 2885 case SM_PH2_W4_RANDOM_TK: 2886 { 2887 // map random to 0-999999 without speding much cycles on a modulus operation 2888 uint32_t tk = little_endian_read_32(data,0); 2889 tk = tk & 0xfffff; // 1048575 2890 if (tk >= 999999){ 2891 tk = tk - 999999; 2892 } 2893 sm_reset_tk(); 2894 big_endian_store_32(setup->sm_tk, 12, tk); 2895 if (IS_RESPONDER(connection->sm_role)){ 2896 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2897 } else { 2898 if (setup->sm_use_secure_connections){ 2899 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2900 } else { 2901 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2902 sm_trigger_user_response(connection); 2903 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2904 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2905 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2906 } 2907 } 2908 } 2909 return; 2910 } 2911 case SM_PH2_C1_W4_RANDOM_A: 2912 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2913 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2914 return; 2915 case SM_PH2_C1_W4_RANDOM_B: 2916 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2917 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2918 return; 2919 case SM_PH3_W4_RANDOM: 2920 reverse_64(data, setup->sm_local_rand); 2921 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2922 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2923 // no db for authenticated flag hack: store flag in bit 4 of LSB 2924 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2925 connection->sm_engine_state = SM_PH3_GET_DIV; 2926 return; 2927 case SM_PH3_W4_DIV: 2928 // use 16 bit from random value as div 2929 setup->sm_local_div = big_endian_read_16(data, 0); 2930 log_info_hex16("div", setup->sm_local_div); 2931 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2932 return; 2933 default: 2934 break; 2935 } 2936 } 2937 2938 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2939 2940 UNUSED(channel); 2941 UNUSED(size); 2942 2943 sm_connection_t * sm_conn; 2944 hci_con_handle_t con_handle; 2945 2946 switch (packet_type) { 2947 2948 case HCI_EVENT_PACKET: 2949 switch (hci_event_packet_get_type(packet)) { 2950 2951 case BTSTACK_EVENT_STATE: 2952 // bt stack activated, get started 2953 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2954 log_info("HCI Working!"); 2955 2956 // set local addr for le device db 2957 bd_addr_t local_bd_addr; 2958 gap_local_bd_addr(local_bd_addr); 2959 le_device_db_set_local_bd_addr(local_bd_addr); 2960 2961 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2962 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2963 if (!sm_have_ec_keypair){ 2964 setup->sm_passkey_bit = 0; 2965 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2966 } 2967 #endif 2968 // trigger Random Address generation if requested before 2969 switch (gap_random_adress_type){ 2970 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2971 rau_state = RAU_IDLE; 2972 break; 2973 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2974 rau_state = RAU_SET_ADDRESS; 2975 break; 2976 default: 2977 rau_state = RAU_GET_RANDOM; 2978 break; 2979 } 2980 sm_run(); 2981 } 2982 break; 2983 2984 case HCI_EVENT_LE_META: 2985 switch (packet[2]) { 2986 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2987 2988 log_info("sm: connected"); 2989 2990 if (packet[3]) return; // connection failed 2991 2992 con_handle = little_endian_read_16(packet, 4); 2993 sm_conn = sm_get_connection_for_handle(con_handle); 2994 if (!sm_conn) break; 2995 2996 sm_conn->sm_handle = con_handle; 2997 sm_conn->sm_role = packet[6]; 2998 sm_conn->sm_peer_addr_type = packet[7]; 2999 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3000 3001 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3002 3003 // reset security properties 3004 sm_conn->sm_connection_encrypted = 0; 3005 sm_conn->sm_connection_authenticated = 0; 3006 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3007 sm_conn->sm_le_db_index = -1; 3008 3009 // prepare CSRK lookup (does not involve setup) 3010 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3011 3012 // just connected -> everything else happens in sm_run() 3013 if (IS_RESPONDER(sm_conn->sm_role)){ 3014 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3015 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3016 if (sm_slave_request_security) { 3017 // request security if requested by app 3018 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3019 } else { 3020 // otherwise, wait for pairing request 3021 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3022 } 3023 } 3024 break; 3025 } else { 3026 // master 3027 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3028 } 3029 break; 3030 3031 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3032 con_handle = little_endian_read_16(packet, 3); 3033 sm_conn = sm_get_connection_for_handle(con_handle); 3034 if (!sm_conn) break; 3035 3036 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3037 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3038 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3039 break; 3040 } 3041 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3042 // PH2 SEND LTK as we need to exchange keys in PH3 3043 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3044 break; 3045 } 3046 3047 // store rand and ediv 3048 reverse_64(&packet[5], sm_conn->sm_local_rand); 3049 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3050 3051 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3052 // potentially stored LTK is from the master 3053 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3054 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3055 break; 3056 } 3057 3058 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3059 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3060 #else 3061 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3062 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3063 #endif 3064 break; 3065 3066 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3067 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3068 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3069 log_error("Read Local P256 Public Key failed"); 3070 break; 3071 } 3072 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, ec_qx); 3073 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, ec_qy); 3074 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3075 sm_log_ec_keypair(); 3076 break; 3077 #endif 3078 default: 3079 break; 3080 } 3081 break; 3082 3083 case HCI_EVENT_ENCRYPTION_CHANGE: 3084 con_handle = little_endian_read_16(packet, 3); 3085 sm_conn = sm_get_connection_for_handle(con_handle); 3086 if (!sm_conn) break; 3087 3088 sm_conn->sm_connection_encrypted = packet[5]; 3089 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3090 sm_conn->sm_actual_encryption_key_size); 3091 log_info("event handler, state %u", sm_conn->sm_engine_state); 3092 if (!sm_conn->sm_connection_encrypted) break; 3093 // continue if part of initial pairing 3094 switch (sm_conn->sm_engine_state){ 3095 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3096 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3097 sm_done_for_handle(sm_conn->sm_handle); 3098 break; 3099 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3100 if (IS_RESPONDER(sm_conn->sm_role)){ 3101 // slave 3102 if (setup->sm_use_secure_connections){ 3103 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3104 } else { 3105 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3106 } 3107 } else { 3108 // master 3109 if (sm_key_distribution_all_received(sm_conn)){ 3110 // skip receiving keys as there are none 3111 sm_key_distribution_handle_all_received(sm_conn); 3112 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3113 } else { 3114 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3115 } 3116 } 3117 break; 3118 default: 3119 break; 3120 } 3121 break; 3122 3123 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3124 con_handle = little_endian_read_16(packet, 3); 3125 sm_conn = sm_get_connection_for_handle(con_handle); 3126 if (!sm_conn) break; 3127 3128 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3129 log_info("event handler, state %u", sm_conn->sm_engine_state); 3130 // continue if part of initial pairing 3131 switch (sm_conn->sm_engine_state){ 3132 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3133 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3134 sm_done_for_handle(sm_conn->sm_handle); 3135 break; 3136 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3137 if (IS_RESPONDER(sm_conn->sm_role)){ 3138 // slave 3139 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3140 } else { 3141 // master 3142 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3143 } 3144 break; 3145 default: 3146 break; 3147 } 3148 break; 3149 3150 3151 case HCI_EVENT_DISCONNECTION_COMPLETE: 3152 con_handle = little_endian_read_16(packet, 3); 3153 sm_done_for_handle(con_handle); 3154 sm_conn = sm_get_connection_for_handle(con_handle); 3155 if (!sm_conn) break; 3156 3157 // delete stored bonding on disconnect with authentication failure in ph0 3158 if (sm_conn->sm_role == 0 3159 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3160 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3161 le_device_db_remove(sm_conn->sm_le_db_index); 3162 } 3163 3164 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3165 sm_conn->sm_handle = 0; 3166 break; 3167 3168 case HCI_EVENT_COMMAND_COMPLETE: 3169 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3170 sm_handle_encryption_result(&packet[6]); 3171 break; 3172 } 3173 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3174 sm_handle_random_result(&packet[6]); 3175 break; 3176 } 3177 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3178 // Hack for Nordic nRF5 series that doesn't have public address: 3179 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3180 // - we use this as default for advertisements/connections 3181 if (hci_get_manufacturer() == COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3182 log_info("nRF5: using (fake) public address as random static address"); 3183 bd_addr_t addr; 3184 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3185 gap_random_address_set(addr); 3186 } 3187 } 3188 break; 3189 default: 3190 break; 3191 } 3192 break; 3193 default: 3194 break; 3195 } 3196 3197 sm_run(); 3198 } 3199 3200 static inline int sm_calc_actual_encryption_key_size(int other){ 3201 if (other < sm_min_encryption_key_size) return 0; 3202 if (other < sm_max_encryption_key_size) return other; 3203 return sm_max_encryption_key_size; 3204 } 3205 3206 3207 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3208 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3209 switch (method){ 3210 case JUST_WORKS: 3211 case NK_BOTH_INPUT: 3212 return 1; 3213 default: 3214 return 0; 3215 } 3216 } 3217 // responder 3218 3219 static int sm_passkey_used(stk_generation_method_t method){ 3220 switch (method){ 3221 case PK_RESP_INPUT: 3222 return 1; 3223 default: 3224 return 0; 3225 } 3226 } 3227 #endif 3228 3229 /** 3230 * @return ok 3231 */ 3232 static int sm_validate_stk_generation_method(void){ 3233 // check if STK generation method is acceptable by client 3234 switch (setup->sm_stk_generation_method){ 3235 case JUST_WORKS: 3236 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3237 case PK_RESP_INPUT: 3238 case PK_INIT_INPUT: 3239 case OK_BOTH_INPUT: 3240 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3241 case OOB: 3242 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3243 case NK_BOTH_INPUT: 3244 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3245 return 1; 3246 default: 3247 return 0; 3248 } 3249 } 3250 3251 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3252 3253 UNUSED(size); 3254 3255 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3256 sm_run(); 3257 } 3258 3259 if (packet_type != SM_DATA_PACKET) return; 3260 3261 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3262 if (!sm_conn) return; 3263 3264 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3265 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3266 return; 3267 } 3268 3269 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3270 3271 int err; 3272 UNUSED(err); 3273 3274 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3275 uint8_t buffer[5]; 3276 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3277 buffer[1] = 3; 3278 little_endian_store_16(buffer, 2, con_handle); 3279 buffer[4] = packet[1]; 3280 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3281 return; 3282 } 3283 3284 switch (sm_conn->sm_engine_state){ 3285 3286 // a sm timeout requries a new physical connection 3287 case SM_GENERAL_TIMEOUT: 3288 return; 3289 3290 #ifdef ENABLE_LE_CENTRAL 3291 3292 // Initiator 3293 case SM_INITIATOR_CONNECTED: 3294 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3295 sm_pdu_received_in_wrong_state(sm_conn); 3296 break; 3297 } 3298 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3299 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3300 break; 3301 } 3302 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3303 sm_key_t ltk; 3304 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3305 if (!sm_is_null_key(ltk)){ 3306 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3307 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3308 } else { 3309 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3310 } 3311 break; 3312 } 3313 // otherwise, store security request 3314 sm_conn->sm_security_request_received = 1; 3315 break; 3316 3317 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3318 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3319 sm_pdu_received_in_wrong_state(sm_conn); 3320 break; 3321 } 3322 // store pairing request 3323 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3324 err = sm_stk_generation_init(sm_conn); 3325 if (err){ 3326 setup->sm_pairing_failed_reason = err; 3327 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3328 break; 3329 } 3330 3331 // generate random number first, if we need to show passkey 3332 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3333 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3334 break; 3335 } 3336 3337 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3338 if (setup->sm_use_secure_connections){ 3339 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3340 if (setup->sm_stk_generation_method == JUST_WORKS){ 3341 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3342 sm_trigger_user_response(sm_conn); 3343 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3344 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3345 } 3346 } else { 3347 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3348 } 3349 break; 3350 } 3351 #endif 3352 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3353 sm_trigger_user_response(sm_conn); 3354 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3355 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3356 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3357 } 3358 break; 3359 3360 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3361 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3362 sm_pdu_received_in_wrong_state(sm_conn); 3363 break; 3364 } 3365 3366 // store s_confirm 3367 reverse_128(&packet[1], setup->sm_peer_confirm); 3368 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3369 break; 3370 3371 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3372 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3373 sm_pdu_received_in_wrong_state(sm_conn); 3374 break;; 3375 } 3376 3377 // received random value 3378 reverse_128(&packet[1], setup->sm_peer_random); 3379 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3380 break; 3381 #endif 3382 3383 #ifdef ENABLE_LE_PERIPHERAL 3384 // Responder 3385 case SM_RESPONDER_IDLE: 3386 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3387 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3388 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3389 sm_pdu_received_in_wrong_state(sm_conn); 3390 break;; 3391 } 3392 3393 // store pairing request 3394 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3395 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3396 break; 3397 #endif 3398 3399 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3400 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3401 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3402 sm_pdu_received_in_wrong_state(sm_conn); 3403 break; 3404 } 3405 3406 // store public key for DH Key calculation 3407 reverse_256(&packet[01], setup->sm_peer_qx); 3408 reverse_256(&packet[33], setup->sm_peer_qy); 3409 3410 #ifdef USE_MBEDTLS_FOR_ECDH 3411 // validate public key 3412 mbedtls_ecp_point Q; 3413 mbedtls_ecp_point_init( &Q ); 3414 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3415 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3416 mbedtls_mpi_lset(&Q.Z, 1); 3417 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3418 mbedtls_ecp_point_free( & Q); 3419 if (err){ 3420 log_error("sm: peer public key invalid %x", err); 3421 // uses "unspecified reason", there is no "public key invalid" error code 3422 sm_pdu_received_in_wrong_state(sm_conn); 3423 break; 3424 } 3425 3426 #endif 3427 if (IS_RESPONDER(sm_conn->sm_role)){ 3428 // responder 3429 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3430 } else { 3431 // initiator 3432 // stk generation method 3433 // passkey entry: notify app to show passkey or to request passkey 3434 switch (setup->sm_stk_generation_method){ 3435 case JUST_WORKS: 3436 case NK_BOTH_INPUT: 3437 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3438 break; 3439 case PK_RESP_INPUT: 3440 sm_sc_start_calculating_local_confirm(sm_conn); 3441 break; 3442 case PK_INIT_INPUT: 3443 case OK_BOTH_INPUT: 3444 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3445 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3446 break; 3447 } 3448 sm_sc_start_calculating_local_confirm(sm_conn); 3449 break; 3450 case OOB: 3451 // TODO: implement SC OOB 3452 break; 3453 } 3454 } 3455 break; 3456 3457 case SM_SC_W4_CONFIRMATION: 3458 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3459 sm_pdu_received_in_wrong_state(sm_conn); 3460 break; 3461 } 3462 // received confirm value 3463 reverse_128(&packet[1], setup->sm_peer_confirm); 3464 3465 if (IS_RESPONDER(sm_conn->sm_role)){ 3466 // responder 3467 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3468 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3469 // still waiting for passkey 3470 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3471 break; 3472 } 3473 } 3474 sm_sc_start_calculating_local_confirm(sm_conn); 3475 } else { 3476 // initiator 3477 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3478 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3479 } else { 3480 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3481 } 3482 } 3483 break; 3484 3485 case SM_SC_W4_PAIRING_RANDOM: 3486 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3487 sm_pdu_received_in_wrong_state(sm_conn); 3488 break; 3489 } 3490 3491 // received random value 3492 reverse_128(&packet[1], setup->sm_peer_nonce); 3493 3494 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3495 // only check for JUST WORK/NC in initiator role AND passkey entry 3496 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3497 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3498 } 3499 3500 sm_sc_state_after_receiving_random(sm_conn); 3501 break; 3502 3503 case SM_SC_W2_CALCULATE_G2: 3504 case SM_SC_W4_CALCULATE_G2: 3505 case SM_SC_W2_CALCULATE_F5_SALT: 3506 case SM_SC_W4_CALCULATE_F5_SALT: 3507 case SM_SC_W2_CALCULATE_F5_MACKEY: 3508 case SM_SC_W4_CALCULATE_F5_MACKEY: 3509 case SM_SC_W2_CALCULATE_F5_LTK: 3510 case SM_SC_W4_CALCULATE_F5_LTK: 3511 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3512 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3513 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3514 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3515 sm_pdu_received_in_wrong_state(sm_conn); 3516 break; 3517 } 3518 // store DHKey Check 3519 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3520 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3521 3522 // have we been only waiting for dhkey check command? 3523 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3524 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3525 } 3526 break; 3527 #endif 3528 3529 #ifdef ENABLE_LE_PERIPHERAL 3530 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3531 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3532 sm_pdu_received_in_wrong_state(sm_conn); 3533 break; 3534 } 3535 3536 // received confirm value 3537 reverse_128(&packet[1], setup->sm_peer_confirm); 3538 3539 // notify client to hide shown passkey 3540 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3541 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3542 } 3543 3544 // handle user cancel pairing? 3545 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3546 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3547 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3548 break; 3549 } 3550 3551 // wait for user action? 3552 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3553 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3554 break; 3555 } 3556 3557 // calculate and send local_confirm 3558 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3559 break; 3560 3561 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3562 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3563 sm_pdu_received_in_wrong_state(sm_conn); 3564 break;; 3565 } 3566 3567 // received random value 3568 reverse_128(&packet[1], setup->sm_peer_random); 3569 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3570 break; 3571 #endif 3572 3573 case SM_PH3_RECEIVE_KEYS: 3574 switch(packet[0]){ 3575 case SM_CODE_ENCRYPTION_INFORMATION: 3576 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3577 reverse_128(&packet[1], setup->sm_peer_ltk); 3578 break; 3579 3580 case SM_CODE_MASTER_IDENTIFICATION: 3581 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3582 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3583 reverse_64(&packet[3], setup->sm_peer_rand); 3584 break; 3585 3586 case SM_CODE_IDENTITY_INFORMATION: 3587 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3588 reverse_128(&packet[1], setup->sm_peer_irk); 3589 break; 3590 3591 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3592 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3593 setup->sm_peer_addr_type = packet[1]; 3594 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3595 break; 3596 3597 case SM_CODE_SIGNING_INFORMATION: 3598 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3599 reverse_128(&packet[1], setup->sm_peer_csrk); 3600 break; 3601 default: 3602 // Unexpected PDU 3603 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3604 break; 3605 } 3606 // done with key distribution? 3607 if (sm_key_distribution_all_received(sm_conn)){ 3608 3609 sm_key_distribution_handle_all_received(sm_conn); 3610 3611 if (IS_RESPONDER(sm_conn->sm_role)){ 3612 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3613 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3614 } else { 3615 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3616 sm_done_for_handle(sm_conn->sm_handle); 3617 } 3618 } else { 3619 if (setup->sm_use_secure_connections){ 3620 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3621 } else { 3622 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3623 } 3624 } 3625 } 3626 break; 3627 default: 3628 // Unexpected PDU 3629 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3630 break; 3631 } 3632 3633 // try to send preparared packet 3634 sm_run(); 3635 } 3636 3637 // Security Manager Client API 3638 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3639 sm_get_oob_data = get_oob_data_callback; 3640 } 3641 3642 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3643 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3644 } 3645 3646 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3647 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3648 } 3649 3650 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3651 sm_min_encryption_key_size = min_size; 3652 sm_max_encryption_key_size = max_size; 3653 } 3654 3655 void sm_set_authentication_requirements(uint8_t auth_req){ 3656 sm_auth_req = auth_req; 3657 } 3658 3659 void sm_set_io_capabilities(io_capability_t io_capability){ 3660 sm_io_capabilities = io_capability; 3661 } 3662 3663 #ifdef ENABLE_LE_PERIPHERAL 3664 void sm_set_request_security(int enable){ 3665 sm_slave_request_security = enable; 3666 } 3667 #endif 3668 3669 void sm_set_er(sm_key_t er){ 3670 memcpy(sm_persistent_er, er, 16); 3671 } 3672 3673 void sm_set_ir(sm_key_t ir){ 3674 memcpy(sm_persistent_ir, ir, 16); 3675 } 3676 3677 // Testing support only 3678 void sm_test_set_irk(sm_key_t irk){ 3679 memcpy(sm_persistent_irk, irk, 16); 3680 sm_persistent_irk_ready = 1; 3681 } 3682 3683 void sm_test_use_fixed_local_csrk(void){ 3684 test_use_fixed_local_csrk = 1; 3685 } 3686 3687 void sm_init(void){ 3688 // set some (BTstack default) ER and IR 3689 int i; 3690 sm_key_t er; 3691 sm_key_t ir; 3692 for (i=0;i<16;i++){ 3693 er[i] = 0x30 + i; 3694 ir[i] = 0x90 + i; 3695 } 3696 sm_set_er(er); 3697 sm_set_ir(ir); 3698 // defaults 3699 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3700 | SM_STK_GENERATION_METHOD_OOB 3701 | SM_STK_GENERATION_METHOD_PASSKEY 3702 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3703 3704 sm_max_encryption_key_size = 16; 3705 sm_min_encryption_key_size = 7; 3706 3707 #ifdef ENABLE_CMAC_ENGINE 3708 sm_cmac_state = CMAC_IDLE; 3709 #endif 3710 dkg_state = DKG_W4_WORKING; 3711 rau_state = RAU_W4_WORKING; 3712 sm_aes128_state = SM_AES128_IDLE; 3713 sm_address_resolution_test = -1; // no private address to resolve yet 3714 sm_address_resolution_ah_calculation_active = 0; 3715 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3716 sm_address_resolution_general_queue = NULL; 3717 3718 gap_random_adress_update_period = 15 * 60 * 1000L; 3719 sm_active_connection = 0; 3720 3721 test_use_fixed_local_csrk = 0; 3722 3723 // register for HCI Events from HCI 3724 hci_event_callback_registration.callback = &sm_event_packet_handler; 3725 hci_add_event_handler(&hci_event_callback_registration); 3726 3727 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3728 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3729 3730 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3731 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3732 #endif 3733 3734 #ifdef USE_MBEDTLS_FOR_ECDH 3735 3736 #ifndef HAVE_MALLOC 3737 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3738 #endif 3739 mbedtls_ecp_group_init(&mbedtls_ec_group); 3740 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3741 #if 0 3742 // test 3743 sm_test_use_fixed_ec_keypair(); 3744 if (sm_have_ec_keypair){ 3745 printf("test dhkey check\n"); 3746 sm_key256_t dhkey; 3747 memcpy(setup->sm_peer_qx, ec_qx, 32); 3748 memcpy(setup->sm_peer_qy, ec_qy, 32); 3749 sm_sc_calculate_dhkey(dhkey); 3750 } 3751 #endif 3752 #endif 3753 } 3754 3755 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3756 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3757 memcpy(ec_qx, qx, 32); 3758 memcpy(ec_qy, qy, 32); 3759 memcpy(ec_d, d, 32); 3760 sm_have_ec_keypair = 1; 3761 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3762 #else 3763 UNUSED(qx); 3764 UNUSED(qy); 3765 UNUSED(d); 3766 #endif 3767 } 3768 3769 void sm_test_use_fixed_ec_keypair(void){ 3770 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3771 #ifdef USE_MBEDTLS_FOR_ECDH 3772 // use test keypair from spec 3773 mbedtls_mpi x; 3774 mbedtls_mpi_init(&x); 3775 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3776 mbedtls_mpi_write_binary(&x, ec_d, 32); 3777 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3778 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3779 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3780 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3781 mbedtls_mpi_free(&x); 3782 #endif 3783 sm_have_ec_keypair = 1; 3784 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3785 #endif 3786 } 3787 3788 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3789 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3790 if (!hci_con) return NULL; 3791 return &hci_con->sm_connection; 3792 } 3793 3794 // @returns 0 if not encrypted, 7-16 otherwise 3795 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3796 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3797 if (!sm_conn) return 0; // wrong connection 3798 if (!sm_conn->sm_connection_encrypted) return 0; 3799 return sm_conn->sm_actual_encryption_key_size; 3800 } 3801 3802 int sm_authenticated(hci_con_handle_t con_handle){ 3803 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3804 if (!sm_conn) return 0; // wrong connection 3805 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3806 return sm_conn->sm_connection_authenticated; 3807 } 3808 3809 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3810 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3811 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3812 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3813 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3814 return sm_conn->sm_connection_authorization_state; 3815 } 3816 3817 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3818 switch (sm_conn->sm_engine_state){ 3819 case SM_GENERAL_IDLE: 3820 case SM_RESPONDER_IDLE: 3821 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3822 sm_run(); 3823 break; 3824 default: 3825 break; 3826 } 3827 } 3828 3829 /** 3830 * @brief Trigger Security Request 3831 */ 3832 void sm_send_security_request(hci_con_handle_t con_handle){ 3833 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3834 if (!sm_conn) return; 3835 sm_send_security_request_for_connection(sm_conn); 3836 } 3837 3838 // request pairing 3839 void sm_request_pairing(hci_con_handle_t con_handle){ 3840 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3841 if (!sm_conn) return; // wrong connection 3842 3843 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3844 if (IS_RESPONDER(sm_conn->sm_role)){ 3845 sm_send_security_request_for_connection(sm_conn); 3846 } else { 3847 // used as a trigger to start central/master/initiator security procedures 3848 uint16_t ediv; 3849 sm_key_t ltk; 3850 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3851 switch (sm_conn->sm_irk_lookup_state){ 3852 case IRK_LOOKUP_FAILED: 3853 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3854 break; 3855 case IRK_LOOKUP_SUCCEEDED: 3856 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3857 if (!sm_is_null_key(ltk) || ediv){ 3858 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3859 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3860 } else { 3861 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3862 } 3863 break; 3864 default: 3865 sm_conn->sm_bonding_requested = 1; 3866 break; 3867 } 3868 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3869 sm_conn->sm_bonding_requested = 1; 3870 } 3871 } 3872 sm_run(); 3873 } 3874 3875 // called by client app on authorization request 3876 void sm_authorization_decline(hci_con_handle_t con_handle){ 3877 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3878 if (!sm_conn) return; // wrong connection 3879 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3880 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3881 } 3882 3883 void sm_authorization_grant(hci_con_handle_t con_handle){ 3884 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3885 if (!sm_conn) return; // wrong connection 3886 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3887 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3888 } 3889 3890 // GAP Bonding API 3891 3892 void sm_bonding_decline(hci_con_handle_t con_handle){ 3893 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3894 if (!sm_conn) return; // wrong connection 3895 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3896 3897 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3898 switch (setup->sm_stk_generation_method){ 3899 case PK_RESP_INPUT: 3900 case PK_INIT_INPUT: 3901 case OK_BOTH_INPUT: 3902 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3903 break; 3904 case NK_BOTH_INPUT: 3905 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3906 break; 3907 case JUST_WORKS: 3908 case OOB: 3909 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3910 break; 3911 } 3912 } 3913 sm_run(); 3914 } 3915 3916 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3917 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3918 if (!sm_conn) return; // wrong connection 3919 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3920 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3921 if (setup->sm_use_secure_connections){ 3922 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3923 } else { 3924 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3925 } 3926 } 3927 3928 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3929 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3930 sm_sc_prepare_dhkey_check(sm_conn); 3931 } 3932 #endif 3933 3934 sm_run(); 3935 } 3936 3937 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3938 // for now, it's the same 3939 sm_just_works_confirm(con_handle); 3940 } 3941 3942 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3943 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3944 if (!sm_conn) return; // wrong connection 3945 sm_reset_tk(); 3946 big_endian_store_32(setup->sm_tk, 12, passkey); 3947 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3948 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3949 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3950 } 3951 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3952 memcpy(setup->sm_ra, setup->sm_tk, 16); 3953 memcpy(setup->sm_rb, setup->sm_tk, 16); 3954 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3955 sm_sc_start_calculating_local_confirm(sm_conn); 3956 } 3957 #endif 3958 sm_run(); 3959 } 3960 3961 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3962 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3963 if (!sm_conn) return; // wrong connection 3964 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3965 setup->sm_keypress_notification = action; 3966 sm_run(); 3967 } 3968 3969 /** 3970 * @brief Identify device in LE Device DB 3971 * @param handle 3972 * @returns index from le_device_db or -1 if not found/identified 3973 */ 3974 int sm_le_device_index(hci_con_handle_t con_handle ){ 3975 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3976 if (!sm_conn) return -1; 3977 return sm_conn->sm_le_db_index; 3978 } 3979 3980 static int gap_random_address_type_requires_updates(void){ 3981 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3982 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3983 return 1; 3984 } 3985 3986 static uint8_t own_address_type(void){ 3987 switch (gap_random_adress_type){ 3988 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3989 return BD_ADDR_TYPE_LE_PUBLIC; 3990 default: 3991 return BD_ADDR_TYPE_LE_RANDOM; 3992 } 3993 } 3994 3995 // GAP LE API 3996 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3997 gap_random_address_update_stop(); 3998 gap_random_adress_type = random_address_type; 3999 hci_le_set_own_address_type(own_address_type()); 4000 if (!gap_random_address_type_requires_updates()) return; 4001 gap_random_address_update_start(); 4002 gap_random_address_trigger(); 4003 } 4004 4005 gap_random_address_type_t gap_random_address_get_mode(void){ 4006 return gap_random_adress_type; 4007 } 4008 4009 void gap_random_address_set_update_period(int period_ms){ 4010 gap_random_adress_update_period = period_ms; 4011 if (!gap_random_address_type_requires_updates()) return; 4012 gap_random_address_update_stop(); 4013 gap_random_address_update_start(); 4014 } 4015 4016 void gap_random_address_set(bd_addr_t addr){ 4017 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4018 memcpy(sm_random_address, addr, 6); 4019 if (rau_state == RAU_W4_WORKING) return; 4020 rau_state = RAU_SET_ADDRESS; 4021 sm_run(); 4022 } 4023 4024 #ifdef ENABLE_LE_PERIPHERAL 4025 /* 4026 * @brief Set Advertisement Paramters 4027 * @param adv_int_min 4028 * @param adv_int_max 4029 * @param adv_type 4030 * @param direct_address_type 4031 * @param direct_address 4032 * @param channel_map 4033 * @param filter_policy 4034 * 4035 * @note own_address_type is used from gap_random_address_set_mode 4036 */ 4037 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4038 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4039 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4040 direct_address_typ, direct_address, channel_map, filter_policy); 4041 } 4042 #endif 4043 4044