1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "sm.c" 39 40 #include <stdio.h> 41 #include <string.h> 42 #include <inttypes.h> 43 44 #include "ble/le_device_db.h" 45 #include "ble/core.h" 46 #include "ble/sm.h" 47 #include "btstack_debug.h" 48 #include "btstack_event.h" 49 #include "btstack_linked_list.h" 50 #include "btstack_memory.h" 51 #include "gap.h" 52 #include "hci.h" 53 #include "hci_dump.h" 54 #include "l2cap.h" 55 56 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 57 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 58 #endif 59 60 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 61 #define IS_RESPONDER(role) (role) 62 #else 63 #ifdef ENABLE_LE_CENTRAL 64 // only central - never responder (avoid 'unused variable' warnings) 65 #define IS_RESPONDER(role) (0 && role) 66 #else 67 // only peripheral - always responder (avoid 'unused variable' warnings) 68 #define IS_RESPONDER(role) (1 || role) 69 #endif 70 #endif 71 72 #ifdef ENABLE_LE_SECURE_CONNECTIONS 73 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 74 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 75 #else 76 #define USE_MBEDTLS_FOR_ECDH 77 #endif 78 #endif 79 80 // Software ECDH implementation provided by mbedtls 81 #ifdef USE_MBEDTLS_FOR_ECDH 82 #include "mbedtls/config.h" 83 #include "mbedtls/platform.h" 84 #include "mbedtls/ecp.h" 85 #include "sm_mbedtls_allocator.h" 86 #endif 87 88 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 89 #define ENABLE_CMAC_ENGINE 90 #endif 91 92 // 93 // SM internal types and globals 94 // 95 96 typedef enum { 97 DKG_W4_WORKING, 98 DKG_CALC_IRK, 99 DKG_W4_IRK, 100 DKG_CALC_DHK, 101 DKG_W4_DHK, 102 DKG_READY 103 } derived_key_generation_t; 104 105 typedef enum { 106 RAU_W4_WORKING, 107 RAU_IDLE, 108 RAU_GET_RANDOM, 109 RAU_W4_RANDOM, 110 RAU_GET_ENC, 111 RAU_W4_ENC, 112 RAU_SET_ADDRESS, 113 } random_address_update_t; 114 115 typedef enum { 116 CMAC_IDLE, 117 CMAC_CALC_SUBKEYS, 118 CMAC_W4_SUBKEYS, 119 CMAC_CALC_MI, 120 CMAC_W4_MI, 121 CMAC_CALC_MLAST, 122 CMAC_W4_MLAST 123 } cmac_state_t; 124 125 typedef enum { 126 JUST_WORKS, 127 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 128 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 129 OK_BOTH_INPUT, // Only input on both, both input PK 130 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 131 OOB // OOB available on both sides 132 } stk_generation_method_t; 133 134 typedef enum { 135 SM_USER_RESPONSE_IDLE, 136 SM_USER_RESPONSE_PENDING, 137 SM_USER_RESPONSE_CONFIRM, 138 SM_USER_RESPONSE_PASSKEY, 139 SM_USER_RESPONSE_DECLINE 140 } sm_user_response_t; 141 142 typedef enum { 143 SM_AES128_IDLE, 144 SM_AES128_ACTIVE 145 } sm_aes128_state_t; 146 147 typedef enum { 148 ADDRESS_RESOLUTION_IDLE, 149 ADDRESS_RESOLUTION_GENERAL, 150 ADDRESS_RESOLUTION_FOR_CONNECTION, 151 } address_resolution_mode_t; 152 153 typedef enum { 154 ADDRESS_RESOLUTION_SUCEEDED, 155 ADDRESS_RESOLUTION_FAILED, 156 } address_resolution_event_t; 157 158 typedef enum { 159 EC_KEY_GENERATION_IDLE, 160 EC_KEY_GENERATION_ACTIVE, 161 EC_KEY_GENERATION_W4_KEY, 162 EC_KEY_GENERATION_DONE, 163 } ec_key_generation_state_t; 164 165 typedef enum { 166 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 167 } sm_state_var_t; 168 169 // 170 // GLOBAL DATA 171 // 172 173 static uint8_t test_use_fixed_local_csrk; 174 175 // configuration 176 static uint8_t sm_accepted_stk_generation_methods; 177 static uint8_t sm_max_encryption_key_size; 178 static uint8_t sm_min_encryption_key_size; 179 static uint8_t sm_auth_req = 0; 180 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 181 static uint8_t sm_slave_request_security; 182 #ifdef ENABLE_LE_SECURE_CONNECTIONS 183 static uint8_t sm_have_ec_keypair; 184 #endif 185 186 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 187 static sm_key_t sm_persistent_er; 188 static sm_key_t sm_persistent_ir; 189 190 // derived from sm_persistent_ir 191 static sm_key_t sm_persistent_dhk; 192 static sm_key_t sm_persistent_irk; 193 static uint8_t sm_persistent_irk_ready = 0; // used for testing 194 static derived_key_generation_t dkg_state; 195 196 // derived from sm_persistent_er 197 // .. 198 199 // random address update 200 static random_address_update_t rau_state; 201 static bd_addr_t sm_random_address; 202 203 // CMAC Calculation: General 204 #ifdef ENABLE_CMAC_ENGINE 205 static cmac_state_t sm_cmac_state; 206 static uint16_t sm_cmac_message_len; 207 static sm_key_t sm_cmac_k; 208 static sm_key_t sm_cmac_x; 209 static sm_key_t sm_cmac_m_last; 210 static uint8_t sm_cmac_block_current; 211 static uint8_t sm_cmac_block_count; 212 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 213 static void (*sm_cmac_done_handler)(uint8_t * hash); 214 #endif 215 216 // CMAC for ATT Signed Writes 217 #ifdef ENABLE_LE_SIGNED_WRITE 218 static uint8_t sm_cmac_header[3]; 219 static const uint8_t * sm_cmac_message; 220 static uint8_t sm_cmac_sign_counter[4]; 221 #endif 222 223 // CMAC for Secure Connection functions 224 #ifdef ENABLE_LE_SECURE_CONNECTIONS 225 static sm_connection_t * sm_cmac_connection; 226 static uint8_t sm_cmac_sc_buffer[80]; 227 #endif 228 229 // resolvable private address lookup / CSRK calculation 230 static int sm_address_resolution_test; 231 static int sm_address_resolution_ah_calculation_active; 232 static uint8_t sm_address_resolution_addr_type; 233 static bd_addr_t sm_address_resolution_address; 234 static void * sm_address_resolution_context; 235 static address_resolution_mode_t sm_address_resolution_mode; 236 static btstack_linked_list_t sm_address_resolution_general_queue; 237 238 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 239 static sm_aes128_state_t sm_aes128_state; 240 static void * sm_aes128_context; 241 242 // random engine. store context (ususally sm_connection_t) 243 static void * sm_random_context; 244 245 // to receive hci events 246 static btstack_packet_callback_registration_t hci_event_callback_registration; 247 248 /* to dispatch sm event */ 249 static btstack_linked_list_t sm_event_handlers; 250 251 // LE Secure Connections 252 #ifdef ENABLE_LE_SECURE_CONNECTIONS 253 static ec_key_generation_state_t ec_key_generation_state; 254 static uint8_t ec_d[32]; 255 static uint8_t ec_qx[32]; 256 static uint8_t ec_qy[32]; 257 #endif 258 259 // Software ECDH implementation provided by mbedtls 260 #ifdef USE_MBEDTLS_FOR_ECDH 261 // group is always valid 262 static mbedtls_ecp_group mbedtls_ec_group; 263 #ifndef HAVE_MALLOC 264 // COMP Method with Window 2 265 // 1300 bytes with 23 allocations 266 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 267 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 268 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 269 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 270 #endif 271 #endif 272 273 // 274 // Volume 3, Part H, Chapter 24 275 // "Security shall be initiated by the Security Manager in the device in the master role. 276 // The device in the slave role shall be the responding device." 277 // -> master := initiator, slave := responder 278 // 279 280 // data needed for security setup 281 typedef struct sm_setup_context { 282 283 btstack_timer_source_t sm_timeout; 284 285 // used in all phases 286 uint8_t sm_pairing_failed_reason; 287 288 // user response, (Phase 1 and/or 2) 289 uint8_t sm_user_response; 290 uint8_t sm_keypress_notification; 291 292 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 293 int sm_key_distribution_send_set; 294 int sm_key_distribution_received_set; 295 296 // Phase 2 (Pairing over SMP) 297 stk_generation_method_t sm_stk_generation_method; 298 sm_key_t sm_tk; 299 uint8_t sm_use_secure_connections; 300 301 sm_key_t sm_c1_t3_value; // c1 calculation 302 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 303 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 304 sm_key_t sm_local_random; 305 sm_key_t sm_local_confirm; 306 sm_key_t sm_peer_random; 307 sm_key_t sm_peer_confirm; 308 uint8_t sm_m_addr_type; // address and type can be removed 309 uint8_t sm_s_addr_type; // '' 310 bd_addr_t sm_m_address; // '' 311 bd_addr_t sm_s_address; // '' 312 sm_key_t sm_ltk; 313 314 uint8_t sm_state_vars; 315 #ifdef ENABLE_LE_SECURE_CONNECTIONS 316 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 317 uint8_t sm_peer_qy[32]; // '' 318 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 319 sm_key_t sm_local_nonce; // might be combined with sm_local_random 320 sm_key_t sm_peer_dhkey_check; 321 sm_key_t sm_local_dhkey_check; 322 sm_key_t sm_ra; 323 sm_key_t sm_rb; 324 sm_key_t sm_t; // used for f5 and h6 325 sm_key_t sm_mackey; 326 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 327 #endif 328 329 // Phase 3 330 331 // key distribution, we generate 332 uint16_t sm_local_y; 333 uint16_t sm_local_div; 334 uint16_t sm_local_ediv; 335 uint8_t sm_local_rand[8]; 336 sm_key_t sm_local_ltk; 337 sm_key_t sm_local_csrk; 338 sm_key_t sm_local_irk; 339 // sm_local_address/addr_type not needed 340 341 // key distribution, received from peer 342 uint16_t sm_peer_y; 343 uint16_t sm_peer_div; 344 uint16_t sm_peer_ediv; 345 uint8_t sm_peer_rand[8]; 346 sm_key_t sm_peer_ltk; 347 sm_key_t sm_peer_irk; 348 sm_key_t sm_peer_csrk; 349 uint8_t sm_peer_addr_type; 350 bd_addr_t sm_peer_address; 351 352 } sm_setup_context_t; 353 354 // 355 static sm_setup_context_t the_setup; 356 static sm_setup_context_t * setup = &the_setup; 357 358 // active connection - the one for which the_setup is used for 359 static uint16_t sm_active_connection = 0; 360 361 // @returns 1 if oob data is available 362 // stores oob data in provided 16 byte buffer if not null 363 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 364 365 // horizontal: initiator capabilities 366 // vertial: responder capabilities 367 static const stk_generation_method_t stk_generation_method [5] [5] = { 368 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 369 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 370 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 371 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 372 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 373 }; 374 375 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 376 #ifdef ENABLE_LE_SECURE_CONNECTIONS 377 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 378 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 379 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 380 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 381 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 382 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 383 }; 384 #endif 385 386 static void sm_run(void); 387 static void sm_done_for_handle(hci_con_handle_t con_handle); 388 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 389 static inline int sm_calc_actual_encryption_key_size(int other); 390 static int sm_validate_stk_generation_method(void); 391 392 static void log_info_hex16(const char * name, uint16_t value){ 393 log_info("%-6s 0x%04x", name, value); 394 } 395 396 // @returns 1 if all bytes are 0 397 static int sm_is_null(uint8_t * data, int size){ 398 int i; 399 for (i=0; i < size ; i++){ 400 if (data[i]) return 0; 401 } 402 return 1; 403 } 404 405 static int sm_is_null_random(uint8_t random[8]){ 406 return sm_is_null(random, 8); 407 } 408 409 static int sm_is_null_key(uint8_t * key){ 410 return sm_is_null(key, 16); 411 } 412 413 // Key utils 414 static void sm_reset_tk(void){ 415 int i; 416 for (i=0;i<16;i++){ 417 setup->sm_tk[i] = 0; 418 } 419 } 420 421 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 422 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 423 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 424 int i; 425 for (i = max_encryption_size ; i < 16 ; i++){ 426 key[15-i] = 0; 427 } 428 } 429 430 // SMP Timeout implementation 431 432 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 433 // the Security Manager Timer shall be reset and started. 434 // 435 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 436 // 437 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 438 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 439 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 440 // established. 441 442 static void sm_timeout_handler(btstack_timer_source_t * timer){ 443 log_info("SM timeout"); 444 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 445 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 446 sm_done_for_handle(sm_conn->sm_handle); 447 448 // trigger handling of next ready connection 449 sm_run(); 450 } 451 static void sm_timeout_start(sm_connection_t * sm_conn){ 452 btstack_run_loop_remove_timer(&setup->sm_timeout); 453 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 454 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 455 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 456 btstack_run_loop_add_timer(&setup->sm_timeout); 457 } 458 static void sm_timeout_stop(void){ 459 btstack_run_loop_remove_timer(&setup->sm_timeout); 460 } 461 static void sm_timeout_reset(sm_connection_t * sm_conn){ 462 sm_timeout_stop(); 463 sm_timeout_start(sm_conn); 464 } 465 466 // end of sm timeout 467 468 // GAP Random Address updates 469 static gap_random_address_type_t gap_random_adress_type; 470 static btstack_timer_source_t gap_random_address_update_timer; 471 static uint32_t gap_random_adress_update_period; 472 473 static void gap_random_address_trigger(void){ 474 if (rau_state != RAU_IDLE) return; 475 log_info("gap_random_address_trigger"); 476 rau_state = RAU_GET_RANDOM; 477 sm_run(); 478 } 479 480 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 481 UNUSED(timer); 482 483 log_info("GAP Random Address Update due"); 484 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 485 btstack_run_loop_add_timer(&gap_random_address_update_timer); 486 gap_random_address_trigger(); 487 } 488 489 static void gap_random_address_update_start(void){ 490 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 491 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 492 btstack_run_loop_add_timer(&gap_random_address_update_timer); 493 } 494 495 static void gap_random_address_update_stop(void){ 496 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 497 } 498 499 500 static void sm_random_start(void * context){ 501 sm_random_context = context; 502 hci_send_cmd(&hci_le_rand); 503 } 504 505 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 506 // context is made availabe to aes128 result handler by this 507 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 508 sm_aes128_state = SM_AES128_ACTIVE; 509 sm_key_t key_flipped, plaintext_flipped; 510 reverse_128(key, key_flipped); 511 reverse_128(plaintext, plaintext_flipped); 512 sm_aes128_context = context; 513 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 514 } 515 516 // ah(k,r) helper 517 // r = padding || r 518 // r - 24 bit value 519 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 520 // r'= padding || r 521 memset(r_prime, 0, 16); 522 memcpy(&r_prime[13], r, 3); 523 } 524 525 // d1 helper 526 // d' = padding || r || d 527 // d,r - 16 bit values 528 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 529 // d'= padding || r || d 530 memset(d1_prime, 0, 16); 531 big_endian_store_16(d1_prime, 12, r); 532 big_endian_store_16(d1_prime, 14, d); 533 } 534 535 // dm helper 536 // r’ = padding || r 537 // r - 64 bit value 538 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 539 memset(r_prime, 0, 16); 540 memcpy(&r_prime[8], r, 8); 541 } 542 543 // calculate arguments for first AES128 operation in C1 function 544 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){ 545 546 // p1 = pres || preq || rat’ || iat’ 547 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 548 // cant octet of pres becomes the most significant octet of p1. 549 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 550 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 551 // p1 is 0x05000800000302070710000001010001." 552 553 sm_key_t p1; 554 reverse_56(pres, &p1[0]); 555 reverse_56(preq, &p1[7]); 556 p1[14] = rat; 557 p1[15] = iat; 558 log_info_key("p1", p1); 559 log_info_key("r", r); 560 561 // t1 = r xor p1 562 int i; 563 for (i=0;i<16;i++){ 564 t1[i] = r[i] ^ p1[i]; 565 } 566 log_info_key("t1", t1); 567 } 568 569 // calculate arguments for second AES128 operation in C1 function 570 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 571 // p2 = padding || ia || ra 572 // "The least significant octet of ra becomes the least significant octet of p2 and 573 // the most significant octet of padding becomes the most significant octet of p2. 574 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 575 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 576 577 sm_key_t p2; 578 memset(p2, 0, 16); 579 memcpy(&p2[4], ia, 6); 580 memcpy(&p2[10], ra, 6); 581 log_info_key("p2", p2); 582 583 // c1 = e(k, t2_xor_p2) 584 int i; 585 for (i=0;i<16;i++){ 586 t3[i] = t2[i] ^ p2[i]; 587 } 588 log_info_key("t3", t3); 589 } 590 591 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 592 log_info_key("r1", r1); 593 log_info_key("r2", r2); 594 memcpy(&r_prime[8], &r2[8], 8); 595 memcpy(&r_prime[0], &r1[8], 8); 596 } 597 598 #ifdef ENABLE_LE_SECURE_CONNECTIONS 599 // Software implementations of crypto toolbox for LE Secure Connection 600 // TODO: replace with code to use AES Engine of HCI Controller 601 typedef uint8_t sm_key24_t[3]; 602 typedef uint8_t sm_key56_t[7]; 603 typedef uint8_t sm_key256_t[32]; 604 605 #if 0 606 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 607 uint32_t rk[RKLENGTH(KEYBITS)]; 608 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 609 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 610 } 611 612 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 613 memcpy(k1, k0, 16); 614 sm_shift_left_by_one_bit_inplace(16, k1); 615 if (k0[0] & 0x80){ 616 k1[15] ^= 0x87; 617 } 618 memcpy(k2, k1, 16); 619 sm_shift_left_by_one_bit_inplace(16, k2); 620 if (k1[0] & 0x80){ 621 k2[15] ^= 0x87; 622 } 623 } 624 625 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 626 sm_key_t k0, k1, k2, zero; 627 memset(zero, 0, 16); 628 629 aes128_calc_cyphertext(key, zero, k0); 630 calc_subkeys(k0, k1, k2); 631 632 int cmac_block_count = (cmac_message_len + 15) / 16; 633 634 // step 3: .. 635 if (cmac_block_count==0){ 636 cmac_block_count = 1; 637 } 638 639 // step 4: set m_last 640 sm_key_t cmac_m_last; 641 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 642 int i; 643 if (sm_cmac_last_block_complete){ 644 for (i=0;i<16;i++){ 645 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 646 } 647 } else { 648 int valid_octets_in_last_block = cmac_message_len & 0x0f; 649 for (i=0;i<16;i++){ 650 if (i < valid_octets_in_last_block){ 651 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 652 continue; 653 } 654 if (i == valid_octets_in_last_block){ 655 cmac_m_last[i] = 0x80 ^ k2[i]; 656 continue; 657 } 658 cmac_m_last[i] = k2[i]; 659 } 660 } 661 662 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 663 // LOG_KEY(cmac_m_last); 664 665 // Step 5 666 sm_key_t cmac_x; 667 memset(cmac_x, 0, 16); 668 669 // Step 6 670 sm_key_t sm_cmac_y; 671 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 672 for (i=0;i<16;i++){ 673 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 674 } 675 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 676 } 677 for (i=0;i<16;i++){ 678 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 679 } 680 681 // Step 7 682 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 683 } 684 #endif 685 #endif 686 687 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){ 688 event[0] = type; 689 event[1] = event_size - 2; 690 little_endian_store_16(event, 2, con_handle); 691 event[4] = addr_type; 692 reverse_bd_addr(address, &event[5]); 693 } 694 695 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 696 UNUSED(channel); 697 698 // log event 699 hci_dump_packet(packet_type, 1, packet, size); 700 // dispatch to all event handlers 701 btstack_linked_list_iterator_t it; 702 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 703 while (btstack_linked_list_iterator_has_next(&it)){ 704 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 705 entry->callback(packet_type, 0, packet, size); 706 } 707 } 708 709 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 710 uint8_t event[11]; 711 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 712 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 713 } 714 715 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){ 716 uint8_t event[15]; 717 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 718 little_endian_store_32(event, 11, passkey); 719 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 720 } 721 722 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){ 723 // fetch addr and addr type from db 724 bd_addr_t identity_address; 725 int identity_address_type; 726 le_device_db_info(index, &identity_address_type, identity_address, NULL); 727 728 uint8_t event[19]; 729 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 730 event[11] = identity_address_type; 731 reverse_bd_addr(identity_address, &event[12]); 732 event[18] = index; 733 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 734 } 735 736 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){ 737 738 uint8_t event[18]; 739 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 740 event[11] = result; 741 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 742 } 743 744 // decide on stk generation based on 745 // - pairing request 746 // - io capabilities 747 // - OOB data availability 748 static void sm_setup_tk(void){ 749 750 // default: just works 751 setup->sm_stk_generation_method = JUST_WORKS; 752 753 #ifdef ENABLE_LE_SECURE_CONNECTIONS 754 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 755 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 756 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 757 memset(setup->sm_ra, 0, 16); 758 memset(setup->sm_rb, 0, 16); 759 #else 760 setup->sm_use_secure_connections = 0; 761 #endif 762 763 // If both devices have not set the MITM option in the Authentication Requirements 764 // Flags, then the IO capabilities shall be ignored and the Just Works association 765 // model shall be used. 766 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 767 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 768 log_info("SM: MITM not required by both -> JUST WORKS"); 769 return; 770 } 771 772 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 773 774 // If both devices have out of band authentication data, then the Authentication 775 // Requirements Flags shall be ignored when selecting the pairing method and the 776 // Out of Band pairing method shall be used. 777 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 778 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 779 log_info("SM: have OOB data"); 780 log_info_key("OOB", setup->sm_tk); 781 setup->sm_stk_generation_method = OOB; 782 return; 783 } 784 785 // Reset TK as it has been setup in sm_init_setup 786 sm_reset_tk(); 787 788 // Also use just works if unknown io capabilites 789 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)){ 790 return; 791 } 792 793 // Otherwise the IO capabilities of the devices shall be used to determine the 794 // pairing method as defined in Table 2.4. 795 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 796 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 797 798 #ifdef ENABLE_LE_SECURE_CONNECTIONS 799 // table not define by default 800 if (setup->sm_use_secure_connections){ 801 generation_method = stk_generation_method_with_secure_connection; 802 } 803 #endif 804 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)]; 805 806 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 807 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); 808 } 809 810 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 811 int flags = 0; 812 if (key_set & SM_KEYDIST_ENC_KEY){ 813 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 814 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 815 } 816 if (key_set & SM_KEYDIST_ID_KEY){ 817 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 818 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 819 } 820 if (key_set & SM_KEYDIST_SIGN){ 821 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 822 } 823 return flags; 824 } 825 826 static void sm_setup_key_distribution(uint8_t key_set){ 827 setup->sm_key_distribution_received_set = 0; 828 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 829 } 830 831 // CSRK Key Lookup 832 833 834 static int sm_address_resolution_idle(void){ 835 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 836 } 837 838 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){ 839 memcpy(sm_address_resolution_address, addr, 6); 840 sm_address_resolution_addr_type = addr_type; 841 sm_address_resolution_test = 0; 842 sm_address_resolution_mode = mode; 843 sm_address_resolution_context = context; 844 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 845 } 846 847 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 848 // check if already in list 849 btstack_linked_list_iterator_t it; 850 sm_lookup_entry_t * entry; 851 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 852 while(btstack_linked_list_iterator_has_next(&it)){ 853 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 854 if (entry->address_type != address_type) continue; 855 if (memcmp(entry->address, address, 6)) continue; 856 // already in list 857 return BTSTACK_BUSY; 858 } 859 entry = btstack_memory_sm_lookup_entry_get(); 860 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 861 entry->address_type = (bd_addr_type_t) address_type; 862 memcpy(entry->address, address, 6); 863 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 864 sm_run(); 865 return 0; 866 } 867 868 // 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 869 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 870 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 871 } 872 static inline void dkg_next_state(void){ 873 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 874 } 875 static inline void rau_next_state(void){ 876 rau_state = (random_address_update_t) (((int)rau_state) + 1); 877 } 878 879 // CMAC calculation using AES Engine 880 #ifdef ENABLE_CMAC_ENGINE 881 882 static inline void sm_cmac_next_state(void){ 883 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 884 } 885 886 static int sm_cmac_last_block_complete(void){ 887 if (sm_cmac_message_len == 0) return 0; 888 return (sm_cmac_message_len & 0x0f) == 0; 889 } 890 891 int sm_cmac_ready(void){ 892 return sm_cmac_state == CMAC_IDLE; 893 } 894 895 // generic cmac calculation 896 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])){ 897 // Generalized CMAC 898 memcpy(sm_cmac_k, key, 16); 899 memset(sm_cmac_x, 0, 16); 900 sm_cmac_block_current = 0; 901 sm_cmac_message_len = message_len; 902 sm_cmac_done_handler = done_callback; 903 sm_cmac_get_byte = get_byte_callback; 904 905 // step 2: n := ceil(len/const_Bsize); 906 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 907 908 // step 3: .. 909 if (sm_cmac_block_count==0){ 910 sm_cmac_block_count = 1; 911 } 912 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 913 914 // first, we need to compute l for k1, k2, and m_last 915 sm_cmac_state = CMAC_CALC_SUBKEYS; 916 917 // let's go 918 sm_run(); 919 } 920 #endif 921 922 // cmac for ATT Message signing 923 #ifdef ENABLE_LE_SIGNED_WRITE 924 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 925 if (offset >= sm_cmac_message_len) { 926 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 927 return 0; 928 } 929 930 offset = sm_cmac_message_len - 1 - offset; 931 932 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 933 if (offset < 3){ 934 return sm_cmac_header[offset]; 935 } 936 int actual_message_len_incl_header = sm_cmac_message_len - 4; 937 if (offset < actual_message_len_incl_header){ 938 return sm_cmac_message[offset - 3]; 939 } 940 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 941 } 942 943 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)){ 944 // ATT Message Signing 945 sm_cmac_header[0] = opcode; 946 little_endian_store_16(sm_cmac_header, 1, con_handle); 947 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 948 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 949 sm_cmac_message = message; 950 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 951 } 952 #endif 953 954 #ifdef ENABLE_CMAC_ENGINE 955 static void sm_cmac_handle_aes_engine_ready(void){ 956 switch (sm_cmac_state){ 957 case CMAC_CALC_SUBKEYS: { 958 sm_key_t const_zero; 959 memset(const_zero, 0, 16); 960 sm_cmac_next_state(); 961 sm_aes128_start(sm_cmac_k, const_zero, NULL); 962 break; 963 } 964 case CMAC_CALC_MI: { 965 int j; 966 sm_key_t y; 967 for (j=0;j<16;j++){ 968 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 969 } 970 sm_cmac_block_current++; 971 sm_cmac_next_state(); 972 sm_aes128_start(sm_cmac_k, y, NULL); 973 break; 974 } 975 case CMAC_CALC_MLAST: { 976 int i; 977 sm_key_t y; 978 for (i=0;i<16;i++){ 979 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 980 } 981 log_info_key("Y", y); 982 sm_cmac_block_current++; 983 sm_cmac_next_state(); 984 sm_aes128_start(sm_cmac_k, y, NULL); 985 break; 986 } 987 default: 988 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 989 break; 990 } 991 } 992 993 // CMAC Implementation using AES128 engine 994 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 995 int i; 996 int carry = 0; 997 for (i=len-1; i >= 0 ; i--){ 998 int new_carry = data[i] >> 7; 999 data[i] = data[i] << 1 | carry; 1000 carry = new_carry; 1001 } 1002 } 1003 1004 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1005 switch (sm_cmac_state){ 1006 case CMAC_W4_SUBKEYS: { 1007 sm_key_t k1; 1008 memcpy(k1, data, 16); 1009 sm_shift_left_by_one_bit_inplace(16, k1); 1010 if (data[0] & 0x80){ 1011 k1[15] ^= 0x87; 1012 } 1013 sm_key_t k2; 1014 memcpy(k2, k1, 16); 1015 sm_shift_left_by_one_bit_inplace(16, k2); 1016 if (k1[0] & 0x80){ 1017 k2[15] ^= 0x87; 1018 } 1019 1020 log_info_key("k", sm_cmac_k); 1021 log_info_key("k1", k1); 1022 log_info_key("k2", k2); 1023 1024 // step 4: set m_last 1025 int i; 1026 if (sm_cmac_last_block_complete()){ 1027 for (i=0;i<16;i++){ 1028 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1029 } 1030 } else { 1031 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1032 for (i=0;i<16;i++){ 1033 if (i < valid_octets_in_last_block){ 1034 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1035 continue; 1036 } 1037 if (i == valid_octets_in_last_block){ 1038 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1039 continue; 1040 } 1041 sm_cmac_m_last[i] = k2[i]; 1042 } 1043 } 1044 1045 // next 1046 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1047 break; 1048 } 1049 case CMAC_W4_MI: 1050 memcpy(sm_cmac_x, data, 16); 1051 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1052 break; 1053 case CMAC_W4_MLAST: 1054 // done 1055 log_info("Setting CMAC Engine to IDLE"); 1056 sm_cmac_state = CMAC_IDLE; 1057 log_info_key("CMAC", data); 1058 sm_cmac_done_handler(data); 1059 break; 1060 default: 1061 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1062 break; 1063 } 1064 } 1065 #endif 1066 1067 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1068 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1069 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1070 switch (setup->sm_stk_generation_method){ 1071 case PK_RESP_INPUT: 1072 if (IS_RESPONDER(sm_conn->sm_role)){ 1073 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1074 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1075 } else { 1076 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)); 1077 } 1078 break; 1079 case PK_INIT_INPUT: 1080 if (IS_RESPONDER(sm_conn->sm_role)){ 1081 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1082 } else { 1083 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1084 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1085 } 1086 break; 1087 case OK_BOTH_INPUT: 1088 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1089 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1090 break; 1091 case NK_BOTH_INPUT: 1092 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1093 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)); 1094 break; 1095 case JUST_WORKS: 1096 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1097 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1098 break; 1099 case OOB: 1100 // client already provided OOB data, let's skip notification. 1101 break; 1102 } 1103 } 1104 1105 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1106 int recv_flags; 1107 if (IS_RESPONDER(sm_conn->sm_role)){ 1108 // slave / responder 1109 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1110 } else { 1111 // master / initiator 1112 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1113 } 1114 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1115 return recv_flags == setup->sm_key_distribution_received_set; 1116 } 1117 1118 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1119 if (sm_active_connection == con_handle){ 1120 sm_timeout_stop(); 1121 sm_active_connection = 0; 1122 log_info("sm: connection 0x%x released setup context", con_handle); 1123 } 1124 } 1125 1126 static int sm_key_distribution_flags_for_auth_req(void){ 1127 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1128 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1129 // encryption information only if bonding requested 1130 flags |= SM_KEYDIST_ENC_KEY; 1131 } 1132 return flags; 1133 } 1134 1135 static void sm_reset_setup(void){ 1136 // fill in sm setup 1137 setup->sm_state_vars = 0; 1138 setup->sm_keypress_notification = 0xff; 1139 sm_reset_tk(); 1140 } 1141 1142 static void sm_init_setup(sm_connection_t * sm_conn){ 1143 1144 // fill in sm setup 1145 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1146 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1147 1148 // query client for OOB data 1149 int have_oob_data = 0; 1150 if (sm_get_oob_data) { 1151 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1152 } 1153 1154 sm_pairing_packet_t * local_packet; 1155 if (IS_RESPONDER(sm_conn->sm_role)){ 1156 // slave 1157 local_packet = &setup->sm_s_pres; 1158 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1159 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1160 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1161 } else { 1162 // master 1163 local_packet = &setup->sm_m_preq; 1164 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1165 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1166 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1167 1168 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1169 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1170 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1171 } 1172 1173 uint8_t auth_req = sm_auth_req; 1174 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1175 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1176 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1177 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1178 } 1179 1180 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1181 1182 sm_pairing_packet_t * remote_packet; 1183 int remote_key_request; 1184 if (IS_RESPONDER(sm_conn->sm_role)){ 1185 // slave / responder 1186 remote_packet = &setup->sm_m_preq; 1187 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1188 } else { 1189 // master / initiator 1190 remote_packet = &setup->sm_s_pres; 1191 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1192 } 1193 1194 // check key size 1195 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1196 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1197 1198 // decide on STK generation method 1199 sm_setup_tk(); 1200 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1201 1202 // check if STK generation method is acceptable by client 1203 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1204 1205 // identical to responder 1206 sm_setup_key_distribution(remote_key_request); 1207 1208 // JUST WORKS doens't provide authentication 1209 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1210 1211 return 0; 1212 } 1213 1214 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1215 1216 // cache and reset context 1217 int matched_device_id = sm_address_resolution_test; 1218 address_resolution_mode_t mode = sm_address_resolution_mode; 1219 void * context = sm_address_resolution_context; 1220 1221 // reset context 1222 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1223 sm_address_resolution_context = NULL; 1224 sm_address_resolution_test = -1; 1225 hci_con_handle_t con_handle = 0; 1226 1227 sm_connection_t * sm_connection; 1228 #ifdef ENABLE_LE_CENTRAL 1229 sm_key_t ltk; 1230 #endif 1231 switch (mode){ 1232 case ADDRESS_RESOLUTION_GENERAL: 1233 break; 1234 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1235 sm_connection = (sm_connection_t *) context; 1236 con_handle = sm_connection->sm_handle; 1237 switch (event){ 1238 case ADDRESS_RESOLUTION_SUCEEDED: 1239 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1240 sm_connection->sm_le_db_index = matched_device_id; 1241 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1242 #ifdef ENABLE_LE_CENTRAL 1243 if (sm_connection->sm_role) break; 1244 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1245 sm_connection->sm_security_request_received = 0; 1246 sm_connection->sm_bonding_requested = 0; 1247 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1248 if (!sm_is_null_key(ltk)){ 1249 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1250 } else { 1251 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1252 } 1253 #endif 1254 break; 1255 case ADDRESS_RESOLUTION_FAILED: 1256 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1257 #ifdef ENABLE_LE_CENTRAL 1258 if (sm_connection->sm_role) break; 1259 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1260 sm_connection->sm_security_request_received = 0; 1261 sm_connection->sm_bonding_requested = 0; 1262 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1263 #endif 1264 break; 1265 } 1266 break; 1267 default: 1268 break; 1269 } 1270 1271 switch (event){ 1272 case ADDRESS_RESOLUTION_SUCEEDED: 1273 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1274 break; 1275 case ADDRESS_RESOLUTION_FAILED: 1276 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1277 break; 1278 } 1279 } 1280 1281 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1282 1283 int le_db_index = -1; 1284 1285 // lookup device based on IRK 1286 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1287 int i; 1288 for (i=0; i < le_device_db_count(); i++){ 1289 sm_key_t irk; 1290 bd_addr_t address; 1291 int address_type; 1292 le_device_db_info(i, &address_type, address, irk); 1293 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1294 log_info("sm: device found for IRK, updating"); 1295 le_db_index = i; 1296 break; 1297 } 1298 } 1299 } 1300 1301 // if not found, lookup via public address if possible 1302 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1303 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1304 int i; 1305 for (i=0; i < le_device_db_count(); i++){ 1306 bd_addr_t address; 1307 int address_type; 1308 le_device_db_info(i, &address_type, address, NULL); 1309 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1310 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1311 log_info("sm: device found for public address, updating"); 1312 le_db_index = i; 1313 break; 1314 } 1315 } 1316 } 1317 1318 // if not found, add to db 1319 if (le_db_index < 0) { 1320 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1321 } 1322 1323 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1324 1325 if (le_db_index >= 0){ 1326 1327 #ifdef ENABLE_LE_SIGNED_WRITE 1328 // store local CSRK 1329 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1330 log_info("sm: store local CSRK"); 1331 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1332 le_device_db_local_counter_set(le_db_index, 0); 1333 } 1334 1335 // store remote CSRK 1336 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1337 log_info("sm: store remote CSRK"); 1338 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1339 le_device_db_remote_counter_set(le_db_index, 0); 1340 } 1341 #endif 1342 // store encryption information for secure connections: LTK generated by ECDH 1343 if (setup->sm_use_secure_connections){ 1344 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1345 uint8_t zero_rand[8]; 1346 memset(zero_rand, 0, 8); 1347 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1348 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1349 } 1350 1351 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1352 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1353 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1354 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1355 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1356 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1357 1358 } 1359 } 1360 1361 // keep le_db_index 1362 sm_conn->sm_le_db_index = le_db_index; 1363 } 1364 1365 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1366 setup->sm_pairing_failed_reason = reason; 1367 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1368 } 1369 1370 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1371 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1372 } 1373 1374 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1375 1376 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1377 static int sm_passkey_used(stk_generation_method_t method); 1378 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1379 1380 static void sm_log_ec_keypair(void){ 1381 log_info("Elliptic curve: X"); 1382 log_info_hexdump(ec_qx,32); 1383 log_info("Elliptic curve: Y"); 1384 log_info_hexdump(ec_qy,32); 1385 } 1386 1387 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1388 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1389 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1390 } else { 1391 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1392 } 1393 } 1394 1395 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1396 if (IS_RESPONDER(sm_conn->sm_role)){ 1397 // Responder 1398 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1399 } else { 1400 // Initiator role 1401 switch (setup->sm_stk_generation_method){ 1402 case JUST_WORKS: 1403 sm_sc_prepare_dhkey_check(sm_conn); 1404 break; 1405 1406 case NK_BOTH_INPUT: 1407 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1408 break; 1409 case PK_INIT_INPUT: 1410 case PK_RESP_INPUT: 1411 case OK_BOTH_INPUT: 1412 if (setup->sm_passkey_bit < 20) { 1413 sm_sc_start_calculating_local_confirm(sm_conn); 1414 } else { 1415 sm_sc_prepare_dhkey_check(sm_conn); 1416 } 1417 break; 1418 case OOB: 1419 // TODO: implement SC OOB 1420 break; 1421 } 1422 } 1423 } 1424 1425 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1426 return sm_cmac_sc_buffer[offset]; 1427 } 1428 1429 static void sm_sc_cmac_done(uint8_t * hash){ 1430 log_info("sm_sc_cmac_done: "); 1431 log_info_hexdump(hash, 16); 1432 1433 sm_connection_t * sm_conn = sm_cmac_connection; 1434 sm_cmac_connection = NULL; 1435 link_key_type_t link_key_type; 1436 1437 switch (sm_conn->sm_engine_state){ 1438 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1439 memcpy(setup->sm_local_confirm, hash, 16); 1440 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1441 break; 1442 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1443 // check 1444 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1445 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1446 break; 1447 } 1448 sm_sc_state_after_receiving_random(sm_conn); 1449 break; 1450 case SM_SC_W4_CALCULATE_G2: { 1451 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1452 big_endian_store_32(setup->sm_tk, 12, vab); 1453 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1454 sm_trigger_user_response(sm_conn); 1455 break; 1456 } 1457 case SM_SC_W4_CALCULATE_F5_SALT: 1458 memcpy(setup->sm_t, hash, 16); 1459 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1460 break; 1461 case SM_SC_W4_CALCULATE_F5_MACKEY: 1462 memcpy(setup->sm_mackey, hash, 16); 1463 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1464 break; 1465 case SM_SC_W4_CALCULATE_F5_LTK: 1466 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1467 // Errata Service Release to the Bluetooth Specification: ESR09 1468 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1469 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1470 memcpy(setup->sm_ltk, hash, 16); 1471 memcpy(setup->sm_local_ltk, hash, 16); 1472 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1473 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1474 break; 1475 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1476 memcpy(setup->sm_local_dhkey_check, hash, 16); 1477 if (IS_RESPONDER(sm_conn->sm_role)){ 1478 // responder 1479 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1480 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1481 } else { 1482 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1483 } 1484 } else { 1485 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1486 } 1487 break; 1488 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1489 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1490 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1491 break; 1492 } 1493 if (IS_RESPONDER(sm_conn->sm_role)){ 1494 // responder 1495 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1496 } else { 1497 // initiator 1498 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1499 } 1500 break; 1501 case SM_SC_W4_CALCULATE_H6_ILK: 1502 memcpy(setup->sm_t, hash, 16); 1503 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1504 break; 1505 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1506 reverse_128(hash, setup->sm_t); 1507 link_key_type = sm_conn->sm_connection_authenticated ? 1508 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1509 if (IS_RESPONDER(sm_conn->sm_role)){ 1510 #ifdef ENABLE_CLASSIC 1511 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1512 #endif 1513 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1514 } else { 1515 #ifdef ENABLE_CLASSIC 1516 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1517 #endif 1518 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1519 } 1520 sm_done_for_handle(sm_conn->sm_handle); 1521 break; 1522 default: 1523 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1524 break; 1525 } 1526 sm_run(); 1527 } 1528 1529 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){ 1530 const uint16_t message_len = 65; 1531 sm_cmac_connection = sm_conn; 1532 memcpy(sm_cmac_sc_buffer, u, 32); 1533 memcpy(sm_cmac_sc_buffer+32, v, 32); 1534 sm_cmac_sc_buffer[64] = z; 1535 log_info("f4 key"); 1536 log_info_hexdump(x, 16); 1537 log_info("f4 message"); 1538 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1539 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1540 } 1541 1542 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1543 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1544 static const uint8_t f5_length[] = { 0x01, 0x00}; 1545 1546 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1547 #ifdef USE_MBEDTLS_FOR_ECDH 1548 // da * Pb 1549 mbedtls_mpi d; 1550 mbedtls_ecp_point Q; 1551 mbedtls_ecp_point DH; 1552 mbedtls_mpi_init(&d); 1553 mbedtls_ecp_point_init(&Q); 1554 mbedtls_ecp_point_init(&DH); 1555 mbedtls_mpi_read_binary(&d, ec_d, 32); 1556 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1557 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1558 mbedtls_mpi_lset(&Q.Z, 1); 1559 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1560 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1561 mbedtls_ecp_point_free(&DH); 1562 mbedtls_mpi_free(&d); 1563 mbedtls_ecp_point_free(&Q); 1564 #endif 1565 log_info("dhkey"); 1566 log_info_hexdump(dhkey, 32); 1567 } 1568 1569 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1570 // calculate DHKEY 1571 sm_key256_t dhkey; 1572 sm_sc_calculate_dhkey(dhkey); 1573 1574 // calculate salt for f5 1575 const uint16_t message_len = 32; 1576 sm_cmac_connection = sm_conn; 1577 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1578 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1579 } 1580 1581 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){ 1582 const uint16_t message_len = 53; 1583 sm_cmac_connection = sm_conn; 1584 1585 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1586 sm_cmac_sc_buffer[0] = 0; 1587 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1588 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1589 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1590 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1591 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1592 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1593 log_info("f5 key"); 1594 log_info_hexdump(t, 16); 1595 log_info("f5 message for MacKey"); 1596 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1597 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1598 } 1599 1600 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1601 sm_key56_t bd_addr_master, bd_addr_slave; 1602 bd_addr_master[0] = setup->sm_m_addr_type; 1603 bd_addr_slave[0] = setup->sm_s_addr_type; 1604 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1605 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1606 if (IS_RESPONDER(sm_conn->sm_role)){ 1607 // responder 1608 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1609 } else { 1610 // initiator 1611 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1612 } 1613 } 1614 1615 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1616 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1617 const uint16_t message_len = 53; 1618 sm_cmac_connection = sm_conn; 1619 sm_cmac_sc_buffer[0] = 1; 1620 // 1..52 setup before 1621 log_info("f5 key"); 1622 log_info_hexdump(t, 16); 1623 log_info("f5 message for LTK"); 1624 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1625 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1626 } 1627 1628 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1629 f5_ltk(sm_conn, setup->sm_t); 1630 } 1631 1632 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){ 1633 const uint16_t message_len = 65; 1634 sm_cmac_connection = sm_conn; 1635 memcpy(sm_cmac_sc_buffer, n1, 16); 1636 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1637 memcpy(sm_cmac_sc_buffer+32, r, 16); 1638 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1639 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1640 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1641 log_info("f6 key"); 1642 log_info_hexdump(w, 16); 1643 log_info("f6 message"); 1644 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1645 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1646 } 1647 1648 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1649 // - U is 256 bits 1650 // - V is 256 bits 1651 // - X is 128 bits 1652 // - Y is 128 bits 1653 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){ 1654 const uint16_t message_len = 80; 1655 sm_cmac_connection = sm_conn; 1656 memcpy(sm_cmac_sc_buffer, u, 32); 1657 memcpy(sm_cmac_sc_buffer+32, v, 32); 1658 memcpy(sm_cmac_sc_buffer+64, y, 16); 1659 log_info("g2 key"); 1660 log_info_hexdump(x, 16); 1661 log_info("g2 message"); 1662 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1663 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1664 } 1665 1666 static void g2_calculate(sm_connection_t * sm_conn) { 1667 // calc Va if numeric comparison 1668 if (IS_RESPONDER(sm_conn->sm_role)){ 1669 // responder 1670 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1671 } else { 1672 // initiator 1673 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1674 } 1675 } 1676 1677 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1678 uint8_t z = 0; 1679 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1680 // some form of passkey 1681 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1682 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1683 setup->sm_passkey_bit++; 1684 } 1685 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1686 } 1687 1688 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1689 uint8_t z = 0; 1690 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1691 // some form of passkey 1692 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1693 // sm_passkey_bit was increased before sending confirm value 1694 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1695 } 1696 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1697 } 1698 1699 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1700 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1701 } 1702 1703 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1704 // calculate DHKCheck 1705 sm_key56_t bd_addr_master, bd_addr_slave; 1706 bd_addr_master[0] = setup->sm_m_addr_type; 1707 bd_addr_slave[0] = setup->sm_s_addr_type; 1708 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1709 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1710 uint8_t iocap_a[3]; 1711 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1712 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1713 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1714 uint8_t iocap_b[3]; 1715 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1716 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1717 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1718 if (IS_RESPONDER(sm_conn->sm_role)){ 1719 // responder 1720 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); 1721 } else { 1722 // initiator 1723 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); 1724 } 1725 } 1726 1727 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1728 // validate E = f6() 1729 sm_key56_t bd_addr_master, bd_addr_slave; 1730 bd_addr_master[0] = setup->sm_m_addr_type; 1731 bd_addr_slave[0] = setup->sm_s_addr_type; 1732 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1733 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1734 1735 uint8_t iocap_a[3]; 1736 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1737 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1738 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1739 uint8_t iocap_b[3]; 1740 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1741 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1742 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1743 if (IS_RESPONDER(sm_conn->sm_role)){ 1744 // responder 1745 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); 1746 } else { 1747 // initiator 1748 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); 1749 } 1750 } 1751 1752 1753 // 1754 // Link Key Conversion Function h6 1755 // 1756 // h6(W, keyID) = AES-CMACW(keyID) 1757 // - W is 128 bits 1758 // - keyID is 32 bits 1759 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1760 const uint16_t message_len = 4; 1761 sm_cmac_connection = sm_conn; 1762 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1763 log_info("h6 key"); 1764 log_info_hexdump(w, 16); 1765 log_info("h6 message"); 1766 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1767 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1768 } 1769 1770 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1771 // Errata Service Release to the Bluetooth Specification: ESR09 1772 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1773 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1774 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1775 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1776 } 1777 1778 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1779 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1780 } 1781 1782 #endif 1783 1784 // key management legacy connections: 1785 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1786 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1787 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1788 // - responder reconnects: responder uses LTK receveived from master 1789 1790 // key management secure connections: 1791 // - both devices store same LTK from ECDH key exchange. 1792 1793 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1794 static void sm_load_security_info(sm_connection_t * sm_connection){ 1795 int encryption_key_size; 1796 int authenticated; 1797 int authorized; 1798 1799 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1800 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1801 &encryption_key_size, &authenticated, &authorized); 1802 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1803 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1804 sm_connection->sm_connection_authenticated = authenticated; 1805 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1806 } 1807 #endif 1808 1809 #ifdef ENABLE_LE_PERIPHERAL 1810 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1811 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1812 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1813 // re-establish used key encryption size 1814 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1815 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1816 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1817 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1818 log_info("sm: received ltk request with key size %u, authenticated %u", 1819 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1820 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1821 } 1822 #endif 1823 1824 static void sm_run(void){ 1825 1826 btstack_linked_list_iterator_t it; 1827 1828 // assert that we can send at least commands 1829 if (!hci_can_send_command_packet_now()) return; 1830 1831 // 1832 // non-connection related behaviour 1833 // 1834 1835 // distributed key generation 1836 switch (dkg_state){ 1837 case DKG_CALC_IRK: 1838 // already busy? 1839 if (sm_aes128_state == SM_AES128_IDLE) { 1840 // IRK = d1(IR, 1, 0) 1841 sm_key_t d1_prime; 1842 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1843 dkg_next_state(); 1844 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1845 return; 1846 } 1847 break; 1848 case DKG_CALC_DHK: 1849 // already busy? 1850 if (sm_aes128_state == SM_AES128_IDLE) { 1851 // DHK = d1(IR, 3, 0) 1852 sm_key_t d1_prime; 1853 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1854 dkg_next_state(); 1855 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1856 return; 1857 } 1858 break; 1859 default: 1860 break; 1861 } 1862 1863 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1864 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1865 #ifdef USE_MBEDTLS_FOR_ECDH 1866 sm_random_start(NULL); 1867 #else 1868 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1869 hci_send_cmd(&hci_le_read_local_p256_public_key); 1870 #endif 1871 return; 1872 } 1873 #endif 1874 1875 // random address updates 1876 switch (rau_state){ 1877 case RAU_GET_RANDOM: 1878 rau_next_state(); 1879 sm_random_start(NULL); 1880 return; 1881 case RAU_GET_ENC: 1882 // already busy? 1883 if (sm_aes128_state == SM_AES128_IDLE) { 1884 sm_key_t r_prime; 1885 sm_ah_r_prime(sm_random_address, r_prime); 1886 rau_next_state(); 1887 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1888 return; 1889 } 1890 break; 1891 case RAU_SET_ADDRESS: 1892 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1893 rau_state = RAU_IDLE; 1894 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1895 return; 1896 default: 1897 break; 1898 } 1899 1900 #ifdef ENABLE_CMAC_ENGINE 1901 // CMAC 1902 switch (sm_cmac_state){ 1903 case CMAC_CALC_SUBKEYS: 1904 case CMAC_CALC_MI: 1905 case CMAC_CALC_MLAST: 1906 // already busy? 1907 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1908 sm_cmac_handle_aes_engine_ready(); 1909 return; 1910 default: 1911 break; 1912 } 1913 #endif 1914 1915 // CSRK Lookup 1916 // -- if csrk lookup ready, find connection that require csrk lookup 1917 if (sm_address_resolution_idle()){ 1918 hci_connections_get_iterator(&it); 1919 while(btstack_linked_list_iterator_has_next(&it)){ 1920 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1921 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1922 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1923 // and start lookup 1924 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); 1925 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1926 break; 1927 } 1928 } 1929 } 1930 1931 // -- if csrk lookup ready, resolved addresses for received addresses 1932 if (sm_address_resolution_idle()) { 1933 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1934 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1935 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1936 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1937 btstack_memory_sm_lookup_entry_free(entry); 1938 } 1939 } 1940 1941 // -- Continue with CSRK device lookup by public or resolvable private address 1942 if (!sm_address_resolution_idle()){ 1943 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1944 while (sm_address_resolution_test < le_device_db_count()){ 1945 int addr_type; 1946 bd_addr_t addr; 1947 sm_key_t irk; 1948 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1949 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1950 1951 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1952 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1953 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1954 break; 1955 } 1956 1957 if (sm_address_resolution_addr_type == 0){ 1958 sm_address_resolution_test++; 1959 continue; 1960 } 1961 1962 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1963 1964 log_info("LE Device Lookup: calculate AH"); 1965 log_info_key("IRK", irk); 1966 1967 sm_key_t r_prime; 1968 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1969 sm_address_resolution_ah_calculation_active = 1; 1970 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1971 return; 1972 } 1973 1974 if (sm_address_resolution_test >= le_device_db_count()){ 1975 log_info("LE Device Lookup: not found"); 1976 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1977 } 1978 } 1979 1980 // handle basic actions that don't requires the full context 1981 hci_connections_get_iterator(&it); 1982 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1983 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1984 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1985 switch(sm_connection->sm_engine_state){ 1986 // responder side 1987 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1988 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1989 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1990 return; 1991 1992 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1993 case SM_SC_RECEIVED_LTK_REQUEST: 1994 switch (sm_connection->sm_irk_lookup_state){ 1995 case IRK_LOOKUP_FAILED: 1996 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1997 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1998 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1999 return; 2000 default: 2001 break; 2002 } 2003 break; 2004 #endif 2005 default: 2006 break; 2007 } 2008 } 2009 2010 // 2011 // active connection handling 2012 // -- use loop to handle next connection if lock on setup context is released 2013 2014 while (1) { 2015 2016 // Find connections that requires setup context and make active if no other is locked 2017 hci_connections_get_iterator(&it); 2018 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 2019 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2020 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2021 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2022 int done = 1; 2023 int err; 2024 UNUSED(err); 2025 switch (sm_connection->sm_engine_state) { 2026 #ifdef ENABLE_LE_PERIPHERAL 2027 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2028 // send packet if possible, 2029 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2030 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 2031 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2032 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2033 } else { 2034 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2035 } 2036 // don't lock sxetup context yet 2037 done = 0; 2038 break; 2039 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2040 sm_reset_setup(); 2041 sm_init_setup(sm_connection); 2042 // recover pairing request 2043 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2044 err = sm_stk_generation_init(sm_connection); 2045 if (err){ 2046 setup->sm_pairing_failed_reason = err; 2047 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2048 break; 2049 } 2050 sm_timeout_start(sm_connection); 2051 // generate random number first, if we need to show passkey 2052 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2053 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2054 break; 2055 } 2056 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2057 break; 2058 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2059 sm_reset_setup(); 2060 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2061 break; 2062 #endif 2063 #ifdef ENABLE_LE_CENTRAL 2064 case SM_INITIATOR_PH0_HAS_LTK: 2065 sm_reset_setup(); 2066 sm_load_security_info(sm_connection); 2067 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2068 break; 2069 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2070 sm_reset_setup(); 2071 sm_init_setup(sm_connection); 2072 sm_timeout_start(sm_connection); 2073 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2074 break; 2075 #endif 2076 2077 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2078 case SM_SC_RECEIVED_LTK_REQUEST: 2079 switch (sm_connection->sm_irk_lookup_state){ 2080 case IRK_LOOKUP_SUCCEEDED: 2081 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2082 // start using context by loading security info 2083 sm_reset_setup(); 2084 sm_load_security_info(sm_connection); 2085 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2086 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2087 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2088 break; 2089 } 2090 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2091 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2092 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2093 // don't lock setup context yet 2094 return; 2095 default: 2096 // just wait until IRK lookup is completed 2097 // don't lock setup context yet 2098 done = 0; 2099 break; 2100 } 2101 break; 2102 #endif 2103 default: 2104 done = 0; 2105 break; 2106 } 2107 if (done){ 2108 sm_active_connection = sm_connection->sm_handle; 2109 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2110 } 2111 } 2112 2113 // 2114 // active connection handling 2115 // 2116 2117 if (sm_active_connection == 0) return; 2118 2119 // assert that we could send a SM PDU - not needed for all of the following 2120 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2121 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2122 return; 2123 } 2124 2125 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2126 if (!connection) return; 2127 2128 // send keypress notifications 2129 if (setup->sm_keypress_notification != 0xff){ 2130 uint8_t buffer[2]; 2131 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2132 buffer[1] = setup->sm_keypress_notification; 2133 setup->sm_keypress_notification = 0xff; 2134 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2135 return; 2136 } 2137 2138 sm_key_t plaintext; 2139 int key_distribution_flags; 2140 UNUSED(key_distribution_flags); 2141 2142 log_info("sm_run: state %u", connection->sm_engine_state); 2143 2144 switch (connection->sm_engine_state){ 2145 2146 // general 2147 case SM_GENERAL_SEND_PAIRING_FAILED: { 2148 uint8_t buffer[2]; 2149 buffer[0] = SM_CODE_PAIRING_FAILED; 2150 buffer[1] = setup->sm_pairing_failed_reason; 2151 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2152 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2153 sm_done_for_handle(connection->sm_handle); 2154 break; 2155 } 2156 2157 // responding state 2158 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2159 case SM_SC_W2_GET_RANDOM_A: 2160 sm_random_start(connection); 2161 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2162 break; 2163 case SM_SC_W2_GET_RANDOM_B: 2164 sm_random_start(connection); 2165 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2166 break; 2167 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2168 if (!sm_cmac_ready()) break; 2169 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2170 sm_sc_calculate_local_confirm(connection); 2171 break; 2172 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2173 if (!sm_cmac_ready()) break; 2174 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2175 sm_sc_calculate_remote_confirm(connection); 2176 break; 2177 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2178 if (!sm_cmac_ready()) break; 2179 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2180 sm_sc_calculate_f6_for_dhkey_check(connection); 2181 break; 2182 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2183 if (!sm_cmac_ready()) break; 2184 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2185 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2186 break; 2187 case SM_SC_W2_CALCULATE_F5_SALT: 2188 if (!sm_cmac_ready()) break; 2189 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2190 f5_calculate_salt(connection); 2191 break; 2192 case SM_SC_W2_CALCULATE_F5_MACKEY: 2193 if (!sm_cmac_ready()) break; 2194 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2195 f5_calculate_mackey(connection); 2196 break; 2197 case SM_SC_W2_CALCULATE_F5_LTK: 2198 if (!sm_cmac_ready()) break; 2199 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2200 f5_calculate_ltk(connection); 2201 break; 2202 case SM_SC_W2_CALCULATE_G2: 2203 if (!sm_cmac_ready()) break; 2204 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2205 g2_calculate(connection); 2206 break; 2207 case SM_SC_W2_CALCULATE_H6_ILK: 2208 if (!sm_cmac_ready()) break; 2209 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2210 h6_calculate_ilk(connection); 2211 break; 2212 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2213 if (!sm_cmac_ready()) break; 2214 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2215 h6_calculate_br_edr_link_key(connection); 2216 break; 2217 #endif 2218 2219 #ifdef ENABLE_LE_CENTRAL 2220 // initiator side 2221 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2222 sm_key_t peer_ltk_flipped; 2223 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2224 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2225 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2226 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2227 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2228 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2229 return; 2230 } 2231 2232 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2233 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2234 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2235 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2236 sm_timeout_reset(connection); 2237 break; 2238 #endif 2239 2240 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2241 2242 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2243 uint8_t buffer[65]; 2244 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2245 // 2246 reverse_256(ec_qx, &buffer[1]); 2247 reverse_256(ec_qy, &buffer[33]); 2248 2249 // stk generation method 2250 // passkey entry: notify app to show passkey or to request passkey 2251 switch (setup->sm_stk_generation_method){ 2252 case JUST_WORKS: 2253 case NK_BOTH_INPUT: 2254 if (IS_RESPONDER(connection->sm_role)){ 2255 // responder 2256 sm_sc_start_calculating_local_confirm(connection); 2257 } else { 2258 // initiator 2259 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2260 } 2261 break; 2262 case PK_INIT_INPUT: 2263 case PK_RESP_INPUT: 2264 case OK_BOTH_INPUT: 2265 // use random TK for display 2266 memcpy(setup->sm_ra, setup->sm_tk, 16); 2267 memcpy(setup->sm_rb, setup->sm_tk, 16); 2268 setup->sm_passkey_bit = 0; 2269 2270 if (IS_RESPONDER(connection->sm_role)){ 2271 // responder 2272 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2273 } else { 2274 // initiator 2275 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2276 } 2277 sm_trigger_user_response(connection); 2278 break; 2279 case OOB: 2280 // TODO: implement SC OOB 2281 break; 2282 } 2283 2284 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2285 sm_timeout_reset(connection); 2286 break; 2287 } 2288 case SM_SC_SEND_CONFIRMATION: { 2289 uint8_t buffer[17]; 2290 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2291 reverse_128(setup->sm_local_confirm, &buffer[1]); 2292 if (IS_RESPONDER(connection->sm_role)){ 2293 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2294 } else { 2295 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2296 } 2297 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2298 sm_timeout_reset(connection); 2299 break; 2300 } 2301 case SM_SC_SEND_PAIRING_RANDOM: { 2302 uint8_t buffer[17]; 2303 buffer[0] = SM_CODE_PAIRING_RANDOM; 2304 reverse_128(setup->sm_local_nonce, &buffer[1]); 2305 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2306 if (IS_RESPONDER(connection->sm_role)){ 2307 // responder 2308 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2309 } else { 2310 // initiator 2311 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2312 } 2313 } else { 2314 if (IS_RESPONDER(connection->sm_role)){ 2315 // responder 2316 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2317 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2318 } else { 2319 sm_sc_prepare_dhkey_check(connection); 2320 } 2321 } else { 2322 // initiator 2323 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2324 } 2325 } 2326 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2327 sm_timeout_reset(connection); 2328 break; 2329 } 2330 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2331 uint8_t buffer[17]; 2332 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2333 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2334 2335 if (IS_RESPONDER(connection->sm_role)){ 2336 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2337 } else { 2338 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2339 } 2340 2341 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2342 sm_timeout_reset(connection); 2343 break; 2344 } 2345 2346 #endif 2347 2348 #ifdef ENABLE_LE_PERIPHERAL 2349 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2350 // echo initiator for now 2351 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2352 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2353 2354 if (setup->sm_use_secure_connections){ 2355 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2356 // skip LTK/EDIV for SC 2357 log_info("sm: dropping encryption information flag"); 2358 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2359 } else { 2360 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2361 } 2362 2363 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); 2364 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); 2365 // update key distribution after ENC was dropped 2366 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2367 2368 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2369 sm_timeout_reset(connection); 2370 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2371 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2372 sm_trigger_user_response(connection); 2373 } 2374 return; 2375 #endif 2376 2377 case SM_PH2_SEND_PAIRING_RANDOM: { 2378 uint8_t buffer[17]; 2379 buffer[0] = SM_CODE_PAIRING_RANDOM; 2380 reverse_128(setup->sm_local_random, &buffer[1]); 2381 if (IS_RESPONDER(connection->sm_role)){ 2382 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2383 } else { 2384 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2385 } 2386 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2387 sm_timeout_reset(connection); 2388 break; 2389 } 2390 2391 case SM_PH2_GET_RANDOM_TK: 2392 case SM_PH2_C1_GET_RANDOM_A: 2393 case SM_PH2_C1_GET_RANDOM_B: 2394 case SM_PH3_GET_RANDOM: 2395 case SM_PH3_GET_DIV: 2396 sm_next_responding_state(connection); 2397 sm_random_start(connection); 2398 return; 2399 2400 case SM_PH2_C1_GET_ENC_B: 2401 case SM_PH2_C1_GET_ENC_D: 2402 // already busy? 2403 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2404 sm_next_responding_state(connection); 2405 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2406 return; 2407 2408 case SM_PH3_LTK_GET_ENC: 2409 case SM_RESPONDER_PH4_LTK_GET_ENC: 2410 // already busy? 2411 if (sm_aes128_state == SM_AES128_IDLE) { 2412 sm_key_t d_prime; 2413 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2414 sm_next_responding_state(connection); 2415 sm_aes128_start(sm_persistent_er, d_prime, connection); 2416 return; 2417 } 2418 break; 2419 2420 case SM_PH3_CSRK_GET_ENC: 2421 // already busy? 2422 if (sm_aes128_state == SM_AES128_IDLE) { 2423 sm_key_t d_prime; 2424 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2425 sm_next_responding_state(connection); 2426 sm_aes128_start(sm_persistent_er, d_prime, connection); 2427 return; 2428 } 2429 break; 2430 2431 case SM_PH2_C1_GET_ENC_C: 2432 // already busy? 2433 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2434 // calculate m_confirm using aes128 engine - step 1 2435 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); 2436 sm_next_responding_state(connection); 2437 sm_aes128_start(setup->sm_tk, plaintext, connection); 2438 break; 2439 case SM_PH2_C1_GET_ENC_A: 2440 // already busy? 2441 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2442 // calculate confirm using aes128 engine - step 1 2443 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); 2444 sm_next_responding_state(connection); 2445 sm_aes128_start(setup->sm_tk, plaintext, connection); 2446 break; 2447 case SM_PH2_CALC_STK: 2448 // already busy? 2449 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2450 // calculate STK 2451 if (IS_RESPONDER(connection->sm_role)){ 2452 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2453 } else { 2454 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2455 } 2456 sm_next_responding_state(connection); 2457 sm_aes128_start(setup->sm_tk, plaintext, connection); 2458 break; 2459 case SM_PH3_Y_GET_ENC: 2460 // already busy? 2461 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2462 // PH3B2 - calculate Y from - enc 2463 // Y = dm(DHK, Rand) 2464 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2465 sm_next_responding_state(connection); 2466 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2467 return; 2468 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2469 uint8_t buffer[17]; 2470 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2471 reverse_128(setup->sm_local_confirm, &buffer[1]); 2472 if (IS_RESPONDER(connection->sm_role)){ 2473 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2474 } else { 2475 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2476 } 2477 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2478 sm_timeout_reset(connection); 2479 return; 2480 } 2481 #ifdef ENABLE_LE_PERIPHERAL 2482 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2483 sm_key_t stk_flipped; 2484 reverse_128(setup->sm_ltk, stk_flipped); 2485 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2486 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2487 return; 2488 } 2489 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2490 sm_key_t ltk_flipped; 2491 reverse_128(setup->sm_ltk, ltk_flipped); 2492 connection->sm_engine_state = SM_RESPONDER_IDLE; 2493 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2494 return; 2495 } 2496 case SM_RESPONDER_PH4_Y_GET_ENC: 2497 // already busy? 2498 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2499 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2500 // Y = dm(DHK, Rand) 2501 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2502 sm_next_responding_state(connection); 2503 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2504 return; 2505 #endif 2506 #ifdef ENABLE_LE_CENTRAL 2507 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2508 sm_key_t stk_flipped; 2509 reverse_128(setup->sm_ltk, stk_flipped); 2510 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2511 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2512 return; 2513 } 2514 #endif 2515 2516 case SM_PH3_DISTRIBUTE_KEYS: 2517 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2518 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2519 uint8_t buffer[17]; 2520 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2521 reverse_128(setup->sm_ltk, &buffer[1]); 2522 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2523 sm_timeout_reset(connection); 2524 return; 2525 } 2526 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2527 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2528 uint8_t buffer[11]; 2529 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2530 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2531 reverse_64(setup->sm_local_rand, &buffer[3]); 2532 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2533 sm_timeout_reset(connection); 2534 return; 2535 } 2536 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2537 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2538 uint8_t buffer[17]; 2539 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2540 reverse_128(sm_persistent_irk, &buffer[1]); 2541 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2542 sm_timeout_reset(connection); 2543 return; 2544 } 2545 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2546 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2547 bd_addr_t local_address; 2548 uint8_t buffer[8]; 2549 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2550 gap_le_get_own_address(&buffer[1], local_address); 2551 reverse_bd_addr(local_address, &buffer[2]); 2552 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2553 sm_timeout_reset(connection); 2554 return; 2555 } 2556 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2557 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2558 2559 // hack to reproduce test runs 2560 if (test_use_fixed_local_csrk){ 2561 memset(setup->sm_local_csrk, 0xcc, 16); 2562 } 2563 2564 uint8_t buffer[17]; 2565 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2566 reverse_128(setup->sm_local_csrk, &buffer[1]); 2567 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2568 sm_timeout_reset(connection); 2569 return; 2570 } 2571 2572 // keys are sent 2573 if (IS_RESPONDER(connection->sm_role)){ 2574 // slave -> receive master keys if any 2575 if (sm_key_distribution_all_received(connection)){ 2576 sm_key_distribution_handle_all_received(connection); 2577 connection->sm_engine_state = SM_RESPONDER_IDLE; 2578 sm_done_for_handle(connection->sm_handle); 2579 } else { 2580 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2581 } 2582 } else { 2583 // master -> all done 2584 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2585 sm_done_for_handle(connection->sm_handle); 2586 } 2587 break; 2588 2589 default: 2590 break; 2591 } 2592 2593 // check again if active connection was released 2594 if (sm_active_connection) break; 2595 } 2596 } 2597 2598 // note: aes engine is ready as we just got the aes result 2599 static void sm_handle_encryption_result(uint8_t * data){ 2600 2601 sm_aes128_state = SM_AES128_IDLE; 2602 2603 if (sm_address_resolution_ah_calculation_active){ 2604 sm_address_resolution_ah_calculation_active = 0; 2605 // compare calulated address against connecting device 2606 uint8_t hash[3]; 2607 reverse_24(data, hash); 2608 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2609 log_info("LE Device Lookup: matched resolvable private address"); 2610 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2611 return; 2612 } 2613 // no match, try next 2614 sm_address_resolution_test++; 2615 return; 2616 } 2617 2618 switch (dkg_state){ 2619 case DKG_W4_IRK: 2620 reverse_128(data, sm_persistent_irk); 2621 log_info_key("irk", sm_persistent_irk); 2622 dkg_next_state(); 2623 return; 2624 case DKG_W4_DHK: 2625 reverse_128(data, sm_persistent_dhk); 2626 log_info_key("dhk", sm_persistent_dhk); 2627 dkg_next_state(); 2628 // SM Init Finished 2629 return; 2630 default: 2631 break; 2632 } 2633 2634 switch (rau_state){ 2635 case RAU_W4_ENC: 2636 reverse_24(data, &sm_random_address[3]); 2637 rau_next_state(); 2638 return; 2639 default: 2640 break; 2641 } 2642 2643 #ifdef ENABLE_CMAC_ENGINE 2644 switch (sm_cmac_state){ 2645 case CMAC_W4_SUBKEYS: 2646 case CMAC_W4_MI: 2647 case CMAC_W4_MLAST: 2648 { 2649 sm_key_t t; 2650 reverse_128(data, t); 2651 sm_cmac_handle_encryption_result(t); 2652 } 2653 return; 2654 default: 2655 break; 2656 } 2657 #endif 2658 2659 // retrieve sm_connection provided to sm_aes128_start_encryption 2660 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2661 if (!connection) return; 2662 switch (connection->sm_engine_state){ 2663 case SM_PH2_C1_W4_ENC_A: 2664 case SM_PH2_C1_W4_ENC_C: 2665 { 2666 sm_key_t t2; 2667 reverse_128(data, t2); 2668 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2669 } 2670 sm_next_responding_state(connection); 2671 return; 2672 case SM_PH2_C1_W4_ENC_B: 2673 reverse_128(data, setup->sm_local_confirm); 2674 log_info_key("c1!", setup->sm_local_confirm); 2675 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2676 return; 2677 case SM_PH2_C1_W4_ENC_D: 2678 { 2679 sm_key_t peer_confirm_test; 2680 reverse_128(data, peer_confirm_test); 2681 log_info_key("c1!", peer_confirm_test); 2682 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2683 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2684 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2685 return; 2686 } 2687 if (IS_RESPONDER(connection->sm_role)){ 2688 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2689 } else { 2690 connection->sm_engine_state = SM_PH2_CALC_STK; 2691 } 2692 } 2693 return; 2694 case SM_PH2_W4_STK: 2695 reverse_128(data, setup->sm_ltk); 2696 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2697 log_info_key("stk", setup->sm_ltk); 2698 if (IS_RESPONDER(connection->sm_role)){ 2699 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2700 } else { 2701 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2702 } 2703 return; 2704 case SM_PH3_Y_W4_ENC:{ 2705 sm_key_t y128; 2706 reverse_128(data, y128); 2707 setup->sm_local_y = big_endian_read_16(y128, 14); 2708 log_info_hex16("y", setup->sm_local_y); 2709 // PH3B3 - calculate EDIV 2710 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2711 log_info_hex16("ediv", setup->sm_local_ediv); 2712 // PH3B4 - calculate LTK - enc 2713 // LTK = d1(ER, DIV, 0)) 2714 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2715 return; 2716 } 2717 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2718 sm_key_t y128; 2719 reverse_128(data, y128); 2720 setup->sm_local_y = big_endian_read_16(y128, 14); 2721 log_info_hex16("y", setup->sm_local_y); 2722 2723 // PH3B3 - calculate DIV 2724 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2725 log_info_hex16("ediv", setup->sm_local_ediv); 2726 // PH3B4 - calculate LTK - enc 2727 // LTK = d1(ER, DIV, 0)) 2728 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2729 return; 2730 } 2731 case SM_PH3_LTK_W4_ENC: 2732 reverse_128(data, setup->sm_ltk); 2733 log_info_key("ltk", setup->sm_ltk); 2734 // calc CSRK next 2735 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2736 return; 2737 case SM_PH3_CSRK_W4_ENC: 2738 reverse_128(data, setup->sm_local_csrk); 2739 log_info_key("csrk", setup->sm_local_csrk); 2740 if (setup->sm_key_distribution_send_set){ 2741 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2742 } else { 2743 // no keys to send, just continue 2744 if (IS_RESPONDER(connection->sm_role)){ 2745 // slave -> receive master keys 2746 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2747 } else { 2748 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2749 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2750 } else { 2751 // master -> all done 2752 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2753 sm_done_for_handle(connection->sm_handle); 2754 } 2755 } 2756 } 2757 return; 2758 #ifdef ENABLE_LE_PERIPHERAL 2759 case SM_RESPONDER_PH4_LTK_W4_ENC: 2760 reverse_128(data, setup->sm_ltk); 2761 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2762 log_info_key("ltk", setup->sm_ltk); 2763 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2764 return; 2765 #endif 2766 default: 2767 break; 2768 } 2769 } 2770 2771 #ifdef USE_MBEDTLS_FOR_ECDH 2772 2773 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2774 UNUSED(context); 2775 2776 int offset = setup->sm_passkey_bit; 2777 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2778 while (size) { 2779 if (offset < 32){ 2780 *buffer++ = setup->sm_peer_qx[offset++]; 2781 } else { 2782 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2783 } 2784 size--; 2785 } 2786 setup->sm_passkey_bit = offset; 2787 return 0; 2788 } 2789 #endif 2790 2791 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2792 static void sm_handle_random_result(uint8_t * data){ 2793 2794 #ifdef USE_MBEDTLS_FOR_ECDH 2795 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2796 int num_bytes = setup->sm_passkey_bit; 2797 if (num_bytes < 32){ 2798 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2799 } else { 2800 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2801 } 2802 num_bytes += 8; 2803 setup->sm_passkey_bit = num_bytes; 2804 2805 if (num_bytes >= 64){ 2806 2807 // generate EC key 2808 setup->sm_passkey_bit = 0; 2809 mbedtls_mpi d; 2810 mbedtls_ecp_point P; 2811 mbedtls_mpi_init(&d); 2812 mbedtls_ecp_point_init(&P); 2813 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2814 log_info("gen keypair %x", res); 2815 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2816 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2817 mbedtls_mpi_write_binary(&d, ec_d, 32); 2818 mbedtls_ecp_point_free(&P); 2819 mbedtls_mpi_free(&d); 2820 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2821 log_info("Elliptic curve: d"); 2822 log_info_hexdump(ec_d,32); 2823 sm_log_ec_keypair(); 2824 2825 #if 0 2826 int i; 2827 sm_key256_t dhkey; 2828 for (i=0;i<10;i++){ 2829 // printf("test dhkey check\n"); 2830 memcpy(setup->sm_peer_qx, ec_qx, 32); 2831 memcpy(setup->sm_peer_qy, ec_qy, 32); 2832 sm_sc_calculate_dhkey(dhkey); 2833 // printf("test dhkey check end\n"); 2834 } 2835 #endif 2836 2837 } 2838 } 2839 #endif 2840 2841 switch (rau_state){ 2842 case RAU_W4_RANDOM: 2843 // non-resolvable vs. resolvable 2844 switch (gap_random_adress_type){ 2845 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2846 // resolvable: use random as prand and calc address hash 2847 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2848 memcpy(sm_random_address, data, 3); 2849 sm_random_address[0] &= 0x3f; 2850 sm_random_address[0] |= 0x40; 2851 rau_state = RAU_GET_ENC; 2852 break; 2853 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2854 default: 2855 // "The two most significant bits of the address shall be equal to ‘0’"" 2856 memcpy(sm_random_address, data, 6); 2857 sm_random_address[0] &= 0x3f; 2858 rau_state = RAU_SET_ADDRESS; 2859 break; 2860 } 2861 return; 2862 default: 2863 break; 2864 } 2865 2866 // retrieve sm_connection provided to sm_random_start 2867 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2868 if (!connection) return; 2869 switch (connection->sm_engine_state){ 2870 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2871 case SM_SC_W4_GET_RANDOM_A: 2872 memcpy(&setup->sm_local_nonce[0], data, 8); 2873 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2874 break; 2875 case SM_SC_W4_GET_RANDOM_B: 2876 memcpy(&setup->sm_local_nonce[8], data, 8); 2877 // initiator & jw/nc -> send pairing random 2878 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2879 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2880 break; 2881 } else { 2882 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2883 } 2884 break; 2885 #endif 2886 2887 case SM_PH2_W4_RANDOM_TK: 2888 { 2889 // map random to 0-999999 without speding much cycles on a modulus operation 2890 uint32_t tk = little_endian_read_32(data,0); 2891 tk = tk & 0xfffff; // 1048575 2892 if (tk >= 999999){ 2893 tk = tk - 999999; 2894 } 2895 sm_reset_tk(); 2896 big_endian_store_32(setup->sm_tk, 12, tk); 2897 if (IS_RESPONDER(connection->sm_role)){ 2898 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2899 } else { 2900 if (setup->sm_use_secure_connections){ 2901 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2902 } else { 2903 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2904 sm_trigger_user_response(connection); 2905 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2906 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2907 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2908 } 2909 } 2910 } 2911 return; 2912 } 2913 case SM_PH2_C1_W4_RANDOM_A: 2914 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2915 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2916 return; 2917 case SM_PH2_C1_W4_RANDOM_B: 2918 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2919 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2920 return; 2921 case SM_PH3_W4_RANDOM: 2922 reverse_64(data, setup->sm_local_rand); 2923 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2924 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2925 // no db for authenticated flag hack: store flag in bit 4 of LSB 2926 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2927 connection->sm_engine_state = SM_PH3_GET_DIV; 2928 return; 2929 case SM_PH3_W4_DIV: 2930 // use 16 bit from random value as div 2931 setup->sm_local_div = big_endian_read_16(data, 0); 2932 log_info_hex16("div", setup->sm_local_div); 2933 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2934 return; 2935 default: 2936 break; 2937 } 2938 } 2939 2940 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2941 2942 UNUSED(channel); 2943 UNUSED(size); 2944 2945 sm_connection_t * sm_conn; 2946 hci_con_handle_t con_handle; 2947 2948 switch (packet_type) { 2949 2950 case HCI_EVENT_PACKET: 2951 switch (hci_event_packet_get_type(packet)) { 2952 2953 case BTSTACK_EVENT_STATE: 2954 // bt stack activated, get started 2955 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2956 log_info("HCI Working!"); 2957 2958 // set local addr for le device db 2959 bd_addr_t local_bd_addr; 2960 gap_local_bd_addr(local_bd_addr); 2961 le_device_db_set_local_bd_addr(local_bd_addr); 2962 2963 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2964 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2965 if (!sm_have_ec_keypair){ 2966 setup->sm_passkey_bit = 0; 2967 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2968 } 2969 #endif 2970 // trigger Random Address generation if requested before 2971 switch (gap_random_adress_type){ 2972 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2973 rau_state = RAU_IDLE; 2974 break; 2975 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2976 rau_state = RAU_SET_ADDRESS; 2977 break; 2978 default: 2979 rau_state = RAU_GET_RANDOM; 2980 break; 2981 } 2982 sm_run(); 2983 } 2984 break; 2985 2986 case HCI_EVENT_LE_META: 2987 switch (packet[2]) { 2988 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2989 2990 log_info("sm: connected"); 2991 2992 if (packet[3]) return; // connection failed 2993 2994 con_handle = little_endian_read_16(packet, 4); 2995 sm_conn = sm_get_connection_for_handle(con_handle); 2996 if (!sm_conn) break; 2997 2998 sm_conn->sm_handle = con_handle; 2999 sm_conn->sm_role = packet[6]; 3000 sm_conn->sm_peer_addr_type = packet[7]; 3001 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3002 3003 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3004 3005 // reset security properties 3006 sm_conn->sm_connection_encrypted = 0; 3007 sm_conn->sm_connection_authenticated = 0; 3008 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3009 sm_conn->sm_le_db_index = -1; 3010 3011 // prepare CSRK lookup (does not involve setup) 3012 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3013 3014 // just connected -> everything else happens in sm_run() 3015 if (IS_RESPONDER(sm_conn->sm_role)){ 3016 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3017 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3018 if (sm_slave_request_security) { 3019 // request security if requested by app 3020 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3021 } else { 3022 // otherwise, wait for pairing request 3023 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3024 } 3025 } 3026 break; 3027 } else { 3028 // master 3029 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3030 } 3031 break; 3032 3033 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3034 con_handle = little_endian_read_16(packet, 3); 3035 sm_conn = sm_get_connection_for_handle(con_handle); 3036 if (!sm_conn) break; 3037 3038 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3039 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3040 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3041 break; 3042 } 3043 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3044 // PH2 SEND LTK as we need to exchange keys in PH3 3045 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3046 break; 3047 } 3048 3049 // store rand and ediv 3050 reverse_64(&packet[5], sm_conn->sm_local_rand); 3051 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3052 3053 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3054 // potentially stored LTK is from the master 3055 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 3056 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3057 break; 3058 } 3059 3060 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3061 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3062 #else 3063 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3064 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3065 #endif 3066 break; 3067 3068 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3069 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3070 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3071 log_error("Read Local P256 Public Key failed"); 3072 break; 3073 } 3074 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, ec_qx); 3075 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, ec_qy); 3076 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3077 sm_log_ec_keypair(); 3078 break; 3079 #endif 3080 default: 3081 break; 3082 } 3083 break; 3084 3085 case HCI_EVENT_ENCRYPTION_CHANGE: 3086 con_handle = little_endian_read_16(packet, 3); 3087 sm_conn = sm_get_connection_for_handle(con_handle); 3088 if (!sm_conn) break; 3089 3090 sm_conn->sm_connection_encrypted = packet[5]; 3091 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3092 sm_conn->sm_actual_encryption_key_size); 3093 log_info("event handler, state %u", sm_conn->sm_engine_state); 3094 if (!sm_conn->sm_connection_encrypted) break; 3095 // continue if part of initial pairing 3096 switch (sm_conn->sm_engine_state){ 3097 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3098 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3099 sm_done_for_handle(sm_conn->sm_handle); 3100 break; 3101 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3102 if (IS_RESPONDER(sm_conn->sm_role)){ 3103 // slave 3104 if (setup->sm_use_secure_connections){ 3105 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3106 } else { 3107 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3108 } 3109 } else { 3110 // master 3111 if (sm_key_distribution_all_received(sm_conn)){ 3112 // skip receiving keys as there are none 3113 sm_key_distribution_handle_all_received(sm_conn); 3114 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3115 } else { 3116 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3117 } 3118 } 3119 break; 3120 default: 3121 break; 3122 } 3123 break; 3124 3125 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3126 con_handle = little_endian_read_16(packet, 3); 3127 sm_conn = sm_get_connection_for_handle(con_handle); 3128 if (!sm_conn) break; 3129 3130 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3131 log_info("event handler, state %u", sm_conn->sm_engine_state); 3132 // continue if part of initial pairing 3133 switch (sm_conn->sm_engine_state){ 3134 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3135 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3136 sm_done_for_handle(sm_conn->sm_handle); 3137 break; 3138 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3139 if (IS_RESPONDER(sm_conn->sm_role)){ 3140 // slave 3141 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3142 } else { 3143 // master 3144 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3145 } 3146 break; 3147 default: 3148 break; 3149 } 3150 break; 3151 3152 3153 case HCI_EVENT_DISCONNECTION_COMPLETE: 3154 con_handle = little_endian_read_16(packet, 3); 3155 sm_done_for_handle(con_handle); 3156 sm_conn = sm_get_connection_for_handle(con_handle); 3157 if (!sm_conn) break; 3158 3159 // delete stored bonding on disconnect with authentication failure in ph0 3160 if (sm_conn->sm_role == 0 3161 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3162 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3163 le_device_db_remove(sm_conn->sm_le_db_index); 3164 } 3165 3166 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3167 sm_conn->sm_handle = 0; 3168 break; 3169 3170 case HCI_EVENT_COMMAND_COMPLETE: 3171 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3172 sm_handle_encryption_result(&packet[6]); 3173 break; 3174 } 3175 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3176 sm_handle_random_result(&packet[6]); 3177 break; 3178 } 3179 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3180 // Hack for Nordic nRF5 series that doesn't have public address: 3181 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3182 // - we use this as default for advertisements/connections 3183 if (hci_get_manufacturer() == COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3184 log_info("nRF5: using (fake) public address as random static address"); 3185 bd_addr_t addr; 3186 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3187 gap_random_address_set(addr); 3188 } 3189 } 3190 break; 3191 default: 3192 break; 3193 } 3194 break; 3195 default: 3196 break; 3197 } 3198 3199 sm_run(); 3200 } 3201 3202 static inline int sm_calc_actual_encryption_key_size(int other){ 3203 if (other < sm_min_encryption_key_size) return 0; 3204 if (other < sm_max_encryption_key_size) return other; 3205 return sm_max_encryption_key_size; 3206 } 3207 3208 3209 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3210 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3211 switch (method){ 3212 case JUST_WORKS: 3213 case NK_BOTH_INPUT: 3214 return 1; 3215 default: 3216 return 0; 3217 } 3218 } 3219 // responder 3220 3221 static int sm_passkey_used(stk_generation_method_t method){ 3222 switch (method){ 3223 case PK_RESP_INPUT: 3224 return 1; 3225 default: 3226 return 0; 3227 } 3228 } 3229 #endif 3230 3231 /** 3232 * @return ok 3233 */ 3234 static int sm_validate_stk_generation_method(void){ 3235 // check if STK generation method is acceptable by client 3236 switch (setup->sm_stk_generation_method){ 3237 case JUST_WORKS: 3238 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3239 case PK_RESP_INPUT: 3240 case PK_INIT_INPUT: 3241 case OK_BOTH_INPUT: 3242 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3243 case OOB: 3244 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3245 case NK_BOTH_INPUT: 3246 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3247 return 1; 3248 default: 3249 return 0; 3250 } 3251 } 3252 3253 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3254 3255 UNUSED(size); 3256 3257 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3258 sm_run(); 3259 } 3260 3261 if (packet_type != SM_DATA_PACKET) return; 3262 3263 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3264 if (!sm_conn) return; 3265 3266 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3267 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3268 return; 3269 } 3270 3271 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3272 3273 int err; 3274 UNUSED(err); 3275 3276 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3277 uint8_t buffer[5]; 3278 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3279 buffer[1] = 3; 3280 little_endian_store_16(buffer, 2, con_handle); 3281 buffer[4] = packet[1]; 3282 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3283 return; 3284 } 3285 3286 switch (sm_conn->sm_engine_state){ 3287 3288 // a sm timeout requries a new physical connection 3289 case SM_GENERAL_TIMEOUT: 3290 return; 3291 3292 #ifdef ENABLE_LE_CENTRAL 3293 3294 // Initiator 3295 case SM_INITIATOR_CONNECTED: 3296 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3297 sm_pdu_received_in_wrong_state(sm_conn); 3298 break; 3299 } 3300 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3301 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3302 break; 3303 } 3304 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3305 sm_key_t ltk; 3306 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3307 if (!sm_is_null_key(ltk)){ 3308 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3309 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3310 } else { 3311 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3312 } 3313 break; 3314 } 3315 // otherwise, store security request 3316 sm_conn->sm_security_request_received = 1; 3317 break; 3318 3319 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3320 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3321 sm_pdu_received_in_wrong_state(sm_conn); 3322 break; 3323 } 3324 // store pairing request 3325 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3326 err = sm_stk_generation_init(sm_conn); 3327 if (err){ 3328 setup->sm_pairing_failed_reason = err; 3329 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3330 break; 3331 } 3332 3333 // generate random number first, if we need to show passkey 3334 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3335 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3336 break; 3337 } 3338 3339 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3340 if (setup->sm_use_secure_connections){ 3341 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3342 if (setup->sm_stk_generation_method == JUST_WORKS){ 3343 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3344 sm_trigger_user_response(sm_conn); 3345 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3346 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3347 } 3348 } else { 3349 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3350 } 3351 break; 3352 } 3353 #endif 3354 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3355 sm_trigger_user_response(sm_conn); 3356 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3357 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3358 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3359 } 3360 break; 3361 3362 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3363 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3364 sm_pdu_received_in_wrong_state(sm_conn); 3365 break; 3366 } 3367 3368 // store s_confirm 3369 reverse_128(&packet[1], setup->sm_peer_confirm); 3370 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3371 break; 3372 3373 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3374 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3375 sm_pdu_received_in_wrong_state(sm_conn); 3376 break;; 3377 } 3378 3379 // received random value 3380 reverse_128(&packet[1], setup->sm_peer_random); 3381 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3382 break; 3383 #endif 3384 3385 #ifdef ENABLE_LE_PERIPHERAL 3386 // Responder 3387 case SM_RESPONDER_IDLE: 3388 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3389 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3390 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3391 sm_pdu_received_in_wrong_state(sm_conn); 3392 break;; 3393 } 3394 3395 // store pairing request 3396 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3397 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3398 break; 3399 #endif 3400 3401 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3402 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3403 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3404 sm_pdu_received_in_wrong_state(sm_conn); 3405 break; 3406 } 3407 3408 // store public key for DH Key calculation 3409 reverse_256(&packet[01], setup->sm_peer_qx); 3410 reverse_256(&packet[33], setup->sm_peer_qy); 3411 3412 #ifdef USE_MBEDTLS_FOR_ECDH 3413 // validate public key 3414 mbedtls_ecp_point Q; 3415 mbedtls_ecp_point_init( &Q ); 3416 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3417 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3418 mbedtls_mpi_lset(&Q.Z, 1); 3419 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3420 mbedtls_ecp_point_free( & Q); 3421 if (err){ 3422 log_error("sm: peer public key invalid %x", err); 3423 // uses "unspecified reason", there is no "public key invalid" error code 3424 sm_pdu_received_in_wrong_state(sm_conn); 3425 break; 3426 } 3427 3428 #endif 3429 if (IS_RESPONDER(sm_conn->sm_role)){ 3430 // responder 3431 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3432 } else { 3433 // initiator 3434 // stk generation method 3435 // passkey entry: notify app to show passkey or to request passkey 3436 switch (setup->sm_stk_generation_method){ 3437 case JUST_WORKS: 3438 case NK_BOTH_INPUT: 3439 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3440 break; 3441 case PK_RESP_INPUT: 3442 sm_sc_start_calculating_local_confirm(sm_conn); 3443 break; 3444 case PK_INIT_INPUT: 3445 case OK_BOTH_INPUT: 3446 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3447 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3448 break; 3449 } 3450 sm_sc_start_calculating_local_confirm(sm_conn); 3451 break; 3452 case OOB: 3453 // TODO: implement SC OOB 3454 break; 3455 } 3456 } 3457 break; 3458 3459 case SM_SC_W4_CONFIRMATION: 3460 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3461 sm_pdu_received_in_wrong_state(sm_conn); 3462 break; 3463 } 3464 // received confirm value 3465 reverse_128(&packet[1], setup->sm_peer_confirm); 3466 3467 if (IS_RESPONDER(sm_conn->sm_role)){ 3468 // responder 3469 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3470 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3471 // still waiting for passkey 3472 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3473 break; 3474 } 3475 } 3476 sm_sc_start_calculating_local_confirm(sm_conn); 3477 } else { 3478 // initiator 3479 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3480 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3481 } else { 3482 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3483 } 3484 } 3485 break; 3486 3487 case SM_SC_W4_PAIRING_RANDOM: 3488 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3489 sm_pdu_received_in_wrong_state(sm_conn); 3490 break; 3491 } 3492 3493 // received random value 3494 reverse_128(&packet[1], setup->sm_peer_nonce); 3495 3496 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3497 // only check for JUST WORK/NC in initiator role AND passkey entry 3498 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3499 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3500 } 3501 3502 sm_sc_state_after_receiving_random(sm_conn); 3503 break; 3504 3505 case SM_SC_W2_CALCULATE_G2: 3506 case SM_SC_W4_CALCULATE_G2: 3507 case SM_SC_W2_CALCULATE_F5_SALT: 3508 case SM_SC_W4_CALCULATE_F5_SALT: 3509 case SM_SC_W2_CALCULATE_F5_MACKEY: 3510 case SM_SC_W4_CALCULATE_F5_MACKEY: 3511 case SM_SC_W2_CALCULATE_F5_LTK: 3512 case SM_SC_W4_CALCULATE_F5_LTK: 3513 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3514 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3515 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3516 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3517 sm_pdu_received_in_wrong_state(sm_conn); 3518 break; 3519 } 3520 // store DHKey Check 3521 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3522 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3523 3524 // have we been only waiting for dhkey check command? 3525 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3526 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3527 } 3528 break; 3529 #endif 3530 3531 #ifdef ENABLE_LE_PERIPHERAL 3532 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3533 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3534 sm_pdu_received_in_wrong_state(sm_conn); 3535 break; 3536 } 3537 3538 // received confirm value 3539 reverse_128(&packet[1], setup->sm_peer_confirm); 3540 3541 // notify client to hide shown passkey 3542 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3543 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3544 } 3545 3546 // handle user cancel pairing? 3547 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3548 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3549 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3550 break; 3551 } 3552 3553 // wait for user action? 3554 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3555 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3556 break; 3557 } 3558 3559 // calculate and send local_confirm 3560 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3561 break; 3562 3563 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3564 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3565 sm_pdu_received_in_wrong_state(sm_conn); 3566 break;; 3567 } 3568 3569 // received random value 3570 reverse_128(&packet[1], setup->sm_peer_random); 3571 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3572 break; 3573 #endif 3574 3575 case SM_PH3_RECEIVE_KEYS: 3576 switch(packet[0]){ 3577 case SM_CODE_ENCRYPTION_INFORMATION: 3578 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3579 reverse_128(&packet[1], setup->sm_peer_ltk); 3580 break; 3581 3582 case SM_CODE_MASTER_IDENTIFICATION: 3583 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3584 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3585 reverse_64(&packet[3], setup->sm_peer_rand); 3586 break; 3587 3588 case SM_CODE_IDENTITY_INFORMATION: 3589 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3590 reverse_128(&packet[1], setup->sm_peer_irk); 3591 break; 3592 3593 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3594 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3595 setup->sm_peer_addr_type = packet[1]; 3596 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3597 break; 3598 3599 case SM_CODE_SIGNING_INFORMATION: 3600 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3601 reverse_128(&packet[1], setup->sm_peer_csrk); 3602 break; 3603 default: 3604 // Unexpected PDU 3605 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3606 break; 3607 } 3608 // done with key distribution? 3609 if (sm_key_distribution_all_received(sm_conn)){ 3610 3611 sm_key_distribution_handle_all_received(sm_conn); 3612 3613 if (IS_RESPONDER(sm_conn->sm_role)){ 3614 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3615 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3616 } else { 3617 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3618 sm_done_for_handle(sm_conn->sm_handle); 3619 } 3620 } else { 3621 if (setup->sm_use_secure_connections){ 3622 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3623 } else { 3624 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3625 } 3626 } 3627 } 3628 break; 3629 default: 3630 // Unexpected PDU 3631 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3632 break; 3633 } 3634 3635 // try to send preparared packet 3636 sm_run(); 3637 } 3638 3639 // Security Manager Client API 3640 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3641 sm_get_oob_data = get_oob_data_callback; 3642 } 3643 3644 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3645 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3646 } 3647 3648 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3649 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3650 } 3651 3652 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3653 sm_min_encryption_key_size = min_size; 3654 sm_max_encryption_key_size = max_size; 3655 } 3656 3657 void sm_set_authentication_requirements(uint8_t auth_req){ 3658 sm_auth_req = auth_req; 3659 } 3660 3661 void sm_set_io_capabilities(io_capability_t io_capability){ 3662 sm_io_capabilities = io_capability; 3663 } 3664 3665 #ifdef ENABLE_LE_PERIPHERAL 3666 void sm_set_request_security(int enable){ 3667 sm_slave_request_security = enable; 3668 } 3669 #endif 3670 3671 void sm_set_er(sm_key_t er){ 3672 memcpy(sm_persistent_er, er, 16); 3673 } 3674 3675 void sm_set_ir(sm_key_t ir){ 3676 memcpy(sm_persistent_ir, ir, 16); 3677 } 3678 3679 // Testing support only 3680 void sm_test_set_irk(sm_key_t irk){ 3681 memcpy(sm_persistent_irk, irk, 16); 3682 sm_persistent_irk_ready = 1; 3683 } 3684 3685 void sm_test_use_fixed_local_csrk(void){ 3686 test_use_fixed_local_csrk = 1; 3687 } 3688 3689 void sm_init(void){ 3690 // set some (BTstack default) ER and IR 3691 int i; 3692 sm_key_t er; 3693 sm_key_t ir; 3694 for (i=0;i<16;i++){ 3695 er[i] = 0x30 + i; 3696 ir[i] = 0x90 + i; 3697 } 3698 sm_set_er(er); 3699 sm_set_ir(ir); 3700 // defaults 3701 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3702 | SM_STK_GENERATION_METHOD_OOB 3703 | SM_STK_GENERATION_METHOD_PASSKEY 3704 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3705 3706 sm_max_encryption_key_size = 16; 3707 sm_min_encryption_key_size = 7; 3708 3709 #ifdef ENABLE_CMAC_ENGINE 3710 sm_cmac_state = CMAC_IDLE; 3711 #endif 3712 dkg_state = DKG_W4_WORKING; 3713 rau_state = RAU_W4_WORKING; 3714 sm_aes128_state = SM_AES128_IDLE; 3715 sm_address_resolution_test = -1; // no private address to resolve yet 3716 sm_address_resolution_ah_calculation_active = 0; 3717 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3718 sm_address_resolution_general_queue = NULL; 3719 3720 gap_random_adress_update_period = 15 * 60 * 1000L; 3721 sm_active_connection = 0; 3722 3723 test_use_fixed_local_csrk = 0; 3724 3725 // register for HCI Events from HCI 3726 hci_event_callback_registration.callback = &sm_event_packet_handler; 3727 hci_add_event_handler(&hci_event_callback_registration); 3728 3729 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3730 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3731 3732 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3733 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3734 #endif 3735 3736 #ifdef USE_MBEDTLS_FOR_ECDH 3737 3738 #ifndef HAVE_MALLOC 3739 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3740 #endif 3741 mbedtls_ecp_group_init(&mbedtls_ec_group); 3742 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3743 #if 0 3744 // test 3745 sm_test_use_fixed_ec_keypair(); 3746 if (sm_have_ec_keypair){ 3747 printf("test dhkey check\n"); 3748 sm_key256_t dhkey; 3749 memcpy(setup->sm_peer_qx, ec_qx, 32); 3750 memcpy(setup->sm_peer_qy, ec_qy, 32); 3751 sm_sc_calculate_dhkey(dhkey); 3752 } 3753 #endif 3754 #endif 3755 } 3756 3757 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3758 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3759 memcpy(ec_qx, qx, 32); 3760 memcpy(ec_qy, qy, 32); 3761 memcpy(ec_d, d, 32); 3762 sm_have_ec_keypair = 1; 3763 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3764 #else 3765 UNUSED(qx); 3766 UNUSED(qy); 3767 UNUSED(d); 3768 #endif 3769 } 3770 3771 void sm_test_use_fixed_ec_keypair(void){ 3772 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3773 #ifdef USE_MBEDTLS_FOR_ECDH 3774 // use test keypair from spec 3775 mbedtls_mpi x; 3776 mbedtls_mpi_init(&x); 3777 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3778 mbedtls_mpi_write_binary(&x, ec_d, 32); 3779 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3780 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3781 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3782 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3783 mbedtls_mpi_free(&x); 3784 #endif 3785 sm_have_ec_keypair = 1; 3786 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3787 #endif 3788 } 3789 3790 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3791 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3792 if (!hci_con) return NULL; 3793 return &hci_con->sm_connection; 3794 } 3795 3796 // @returns 0 if not encrypted, 7-16 otherwise 3797 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3798 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3799 if (!sm_conn) return 0; // wrong connection 3800 if (!sm_conn->sm_connection_encrypted) return 0; 3801 return sm_conn->sm_actual_encryption_key_size; 3802 } 3803 3804 int sm_authenticated(hci_con_handle_t con_handle){ 3805 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3806 if (!sm_conn) return 0; // wrong connection 3807 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3808 return sm_conn->sm_connection_authenticated; 3809 } 3810 3811 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3812 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3813 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3814 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3815 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3816 return sm_conn->sm_connection_authorization_state; 3817 } 3818 3819 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3820 switch (sm_conn->sm_engine_state){ 3821 case SM_GENERAL_IDLE: 3822 case SM_RESPONDER_IDLE: 3823 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3824 sm_run(); 3825 break; 3826 default: 3827 break; 3828 } 3829 } 3830 3831 /** 3832 * @brief Trigger Security Request 3833 */ 3834 void sm_send_security_request(hci_con_handle_t con_handle){ 3835 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3836 if (!sm_conn) return; 3837 sm_send_security_request_for_connection(sm_conn); 3838 } 3839 3840 // request pairing 3841 void sm_request_pairing(hci_con_handle_t con_handle){ 3842 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3843 if (!sm_conn) return; // wrong connection 3844 3845 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3846 if (IS_RESPONDER(sm_conn->sm_role)){ 3847 sm_send_security_request_for_connection(sm_conn); 3848 } else { 3849 // used as a trigger to start central/master/initiator security procedures 3850 uint16_t ediv; 3851 sm_key_t ltk; 3852 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3853 switch (sm_conn->sm_irk_lookup_state){ 3854 case IRK_LOOKUP_FAILED: 3855 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3856 break; 3857 case IRK_LOOKUP_SUCCEEDED: 3858 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3859 if (!sm_is_null_key(ltk) || ediv){ 3860 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3861 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3862 } else { 3863 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3864 } 3865 break; 3866 default: 3867 sm_conn->sm_bonding_requested = 1; 3868 break; 3869 } 3870 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3871 sm_conn->sm_bonding_requested = 1; 3872 } 3873 } 3874 sm_run(); 3875 } 3876 3877 // called by client app on authorization request 3878 void sm_authorization_decline(hci_con_handle_t con_handle){ 3879 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3880 if (!sm_conn) return; // wrong connection 3881 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3882 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3883 } 3884 3885 void sm_authorization_grant(hci_con_handle_t con_handle){ 3886 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3887 if (!sm_conn) return; // wrong connection 3888 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3889 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3890 } 3891 3892 // GAP Bonding API 3893 3894 void sm_bonding_decline(hci_con_handle_t con_handle){ 3895 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3896 if (!sm_conn) return; // wrong connection 3897 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3898 3899 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3900 switch (setup->sm_stk_generation_method){ 3901 case PK_RESP_INPUT: 3902 case PK_INIT_INPUT: 3903 case OK_BOTH_INPUT: 3904 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3905 break; 3906 case NK_BOTH_INPUT: 3907 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3908 break; 3909 case JUST_WORKS: 3910 case OOB: 3911 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3912 break; 3913 } 3914 } 3915 sm_run(); 3916 } 3917 3918 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3919 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3920 if (!sm_conn) return; // wrong connection 3921 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3922 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3923 if (setup->sm_use_secure_connections){ 3924 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3925 } else { 3926 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3927 } 3928 } 3929 3930 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3931 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3932 sm_sc_prepare_dhkey_check(sm_conn); 3933 } 3934 #endif 3935 3936 sm_run(); 3937 } 3938 3939 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3940 // for now, it's the same 3941 sm_just_works_confirm(con_handle); 3942 } 3943 3944 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3945 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3946 if (!sm_conn) return; // wrong connection 3947 sm_reset_tk(); 3948 big_endian_store_32(setup->sm_tk, 12, passkey); 3949 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3950 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3951 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3952 } 3953 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3954 memcpy(setup->sm_ra, setup->sm_tk, 16); 3955 memcpy(setup->sm_rb, setup->sm_tk, 16); 3956 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3957 sm_sc_start_calculating_local_confirm(sm_conn); 3958 } 3959 #endif 3960 sm_run(); 3961 } 3962 3963 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3964 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3965 if (!sm_conn) return; // wrong connection 3966 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3967 setup->sm_keypress_notification = action; 3968 sm_run(); 3969 } 3970 3971 /** 3972 * @brief Identify device in LE Device DB 3973 * @param handle 3974 * @returns index from le_device_db or -1 if not found/identified 3975 */ 3976 int sm_le_device_index(hci_con_handle_t con_handle ){ 3977 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3978 if (!sm_conn) return -1; 3979 return sm_conn->sm_le_db_index; 3980 } 3981 3982 static int gap_random_address_type_requires_updates(void){ 3983 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3984 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3985 return 1; 3986 } 3987 3988 static uint8_t own_address_type(void){ 3989 switch (gap_random_adress_type){ 3990 case GAP_RANDOM_ADDRESS_TYPE_OFF: 3991 return BD_ADDR_TYPE_LE_PUBLIC; 3992 default: 3993 return BD_ADDR_TYPE_LE_RANDOM; 3994 } 3995 } 3996 3997 // GAP LE API 3998 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3999 gap_random_address_update_stop(); 4000 gap_random_adress_type = random_address_type; 4001 hci_le_set_own_address_type(own_address_type()); 4002 if (!gap_random_address_type_requires_updates()) return; 4003 gap_random_address_update_start(); 4004 gap_random_address_trigger(); 4005 } 4006 4007 gap_random_address_type_t gap_random_address_get_mode(void){ 4008 return gap_random_adress_type; 4009 } 4010 4011 void gap_random_address_set_update_period(int period_ms){ 4012 gap_random_adress_update_period = period_ms; 4013 if (!gap_random_address_type_requires_updates()) return; 4014 gap_random_address_update_stop(); 4015 gap_random_address_update_start(); 4016 } 4017 4018 void gap_random_address_set(bd_addr_t addr){ 4019 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4020 memcpy(sm_random_address, addr, 6); 4021 if (rau_state == RAU_W4_WORKING) return; 4022 rau_state = RAU_SET_ADDRESS; 4023 sm_run(); 4024 } 4025 4026 #ifdef ENABLE_LE_PERIPHERAL 4027 /* 4028 * @brief Set Advertisement Paramters 4029 * @param adv_int_min 4030 * @param adv_int_max 4031 * @param adv_type 4032 * @param direct_address_type 4033 * @param direct_address 4034 * @param channel_map 4035 * @param filter_policy 4036 * 4037 * @note own_address_type is used from gap_random_address_set_mode 4038 */ 4039 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4040 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4041 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4042 direct_address_typ, direct_address, channel_map, filter_policy); 4043 } 4044 #endif 4045 4046