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