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