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 "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 // TODO: remove software AES 55 #include "rijndael.h" 56 #endif 57 58 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(HAVE_HCI_CONTROLLER_DHKEY_SUPPORT) 59 #define USE_MBEDTLS_FOR_ECDH 60 #endif 61 62 #ifdef ENABLE_LE_SECURE_CONNECTIONS 63 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 64 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 65 #else 66 #define USE_MBEDTLS_FOR_ECDH 67 #endif 68 #endif 69 70 71 // Software ECDH implementation provided by mbedtls 72 #ifdef USE_MBEDTLS_FOR_ECDH 73 #if !defined(MBEDTLS_CONFIG_FILE) 74 #include "mbedtls/config.h" 75 #else 76 #include MBEDTLS_CONFIG_FILE 77 #endif 78 #if defined(MBEDTLS_PLATFORM_C) 79 #include "mbedtls/platform.h" 80 #else 81 #include <stdio.h> 82 #define mbedtls_printf printf 83 #endif 84 #include "mbedtls/ecp.h" 85 #endif 86 87 // 88 // SM internal types and globals 89 // 90 91 typedef enum { 92 DKG_W4_WORKING, 93 DKG_CALC_IRK, 94 DKG_W4_IRK, 95 DKG_CALC_DHK, 96 DKG_W4_DHK, 97 DKG_READY 98 } derived_key_generation_t; 99 100 typedef enum { 101 RAU_W4_WORKING, 102 RAU_IDLE, 103 RAU_GET_RANDOM, 104 RAU_W4_RANDOM, 105 RAU_GET_ENC, 106 RAU_W4_ENC, 107 RAU_SET_ADDRESS, 108 } random_address_update_t; 109 110 typedef enum { 111 CMAC_IDLE, 112 CMAC_CALC_SUBKEYS, 113 CMAC_W4_SUBKEYS, 114 CMAC_CALC_MI, 115 CMAC_W4_MI, 116 CMAC_CALC_MLAST, 117 CMAC_W4_MLAST 118 } cmac_state_t; 119 120 typedef enum { 121 JUST_WORKS, 122 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 123 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 124 OK_BOTH_INPUT, // Only input on both, both input PK 125 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 126 OOB // OOB available on both sides 127 } stk_generation_method_t; 128 129 typedef enum { 130 SM_USER_RESPONSE_IDLE, 131 SM_USER_RESPONSE_PENDING, 132 SM_USER_RESPONSE_CONFIRM, 133 SM_USER_RESPONSE_PASSKEY, 134 SM_USER_RESPONSE_DECLINE 135 } sm_user_response_t; 136 137 typedef enum { 138 SM_AES128_IDLE, 139 SM_AES128_ACTIVE 140 } sm_aes128_state_t; 141 142 typedef enum { 143 ADDRESS_RESOLUTION_IDLE, 144 ADDRESS_RESOLUTION_GENERAL, 145 ADDRESS_RESOLUTION_FOR_CONNECTION, 146 } address_resolution_mode_t; 147 148 typedef enum { 149 ADDRESS_RESOLUTION_SUCEEDED, 150 ADDRESS_RESOLUTION_FAILED, 151 } address_resolution_event_t; 152 153 typedef enum { 154 EC_KEY_GENERATION_IDLE, 155 EC_KEY_GENERATION_ACTIVE, 156 EC_KEY_GENERATION_DONE, 157 } ec_key_generation_state_t; 158 159 typedef enum { 160 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 161 } sm_state_var_t; 162 163 // 164 // GLOBAL DATA 165 // 166 167 static uint8_t test_use_fixed_local_csrk; 168 static uint8_t test_use_fixed_ec_keypair; 169 170 // configuration 171 static uint8_t sm_accepted_stk_generation_methods; 172 static uint8_t sm_max_encryption_key_size; 173 static uint8_t sm_min_encryption_key_size; 174 static uint8_t sm_auth_req = 0; 175 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 176 static uint8_t sm_slave_request_security; 177 178 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 179 static sm_key_t sm_persistent_er; 180 static sm_key_t sm_persistent_ir; 181 182 // derived from sm_persistent_ir 183 static sm_key_t sm_persistent_dhk; 184 static sm_key_t sm_persistent_irk; 185 static uint8_t sm_persistent_irk_ready = 0; // used for testing 186 static derived_key_generation_t dkg_state; 187 188 // derived from sm_persistent_er 189 // .. 190 191 // random address update 192 static random_address_update_t rau_state; 193 static bd_addr_t sm_random_address; 194 195 // CMAC Calculation: General 196 static cmac_state_t sm_cmac_state; 197 static uint16_t sm_cmac_message_len; 198 static sm_key_t sm_cmac_k; 199 static sm_key_t sm_cmac_x; 200 static sm_key_t sm_cmac_m_last; 201 static uint8_t sm_cmac_block_current; 202 static uint8_t sm_cmac_block_count; 203 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 204 static void (*sm_cmac_done_handler)(uint8_t * hash); 205 206 // CMAC for ATT Signed Writes 207 static uint8_t sm_cmac_header[3]; 208 static const uint8_t * sm_cmac_message; 209 static uint8_t sm_cmac_sign_counter[4]; 210 211 // CMAC for Secure Connection functions 212 #ifdef ENABLE_LE_SECURE_CONNECTIONS 213 static sm_connection_t * sm_cmac_connection; 214 static uint8_t sm_cmac_sc_buffer[80]; 215 #endif 216 217 // resolvable private address lookup / CSRK calculation 218 static int sm_address_resolution_test; 219 static int sm_address_resolution_ah_calculation_active; 220 static uint8_t sm_address_resolution_addr_type; 221 static bd_addr_t sm_address_resolution_address; 222 static void * sm_address_resolution_context; 223 static address_resolution_mode_t sm_address_resolution_mode; 224 static btstack_linked_list_t sm_address_resolution_general_queue; 225 226 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 227 static sm_aes128_state_t sm_aes128_state; 228 static void * sm_aes128_context; 229 230 // random engine. store context (ususally sm_connection_t) 231 static void * sm_random_context; 232 233 // to receive hci events 234 static btstack_packet_callback_registration_t hci_event_callback_registration; 235 236 /* to dispatch sm event */ 237 static btstack_linked_list_t sm_event_handlers; 238 239 // Software ECDH implementation provided by mbedtls 240 #ifdef USE_MBEDTLS_FOR_ECDH 241 static mbedtls_ecp_keypair le_keypair; 242 static ec_key_generation_state_t ec_key_generation_state; 243 #endif 244 245 // 246 // Volume 3, Part H, Chapter 24 247 // "Security shall be initiated by the Security Manager in the device in the master role. 248 // The device in the slave role shall be the responding device." 249 // -> master := initiator, slave := responder 250 // 251 252 // data needed for security setup 253 typedef struct sm_setup_context { 254 255 btstack_timer_source_t sm_timeout; 256 257 // used in all phases 258 uint8_t sm_pairing_failed_reason; 259 260 // user response, (Phase 1 and/or 2) 261 uint8_t sm_user_response; 262 263 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 264 int sm_key_distribution_send_set; 265 int sm_key_distribution_received_set; 266 267 // Phase 2 (Pairing over SMP) 268 stk_generation_method_t sm_stk_generation_method; 269 sm_key_t sm_tk; 270 uint8_t sm_use_secure_connections; 271 272 sm_key_t sm_c1_t3_value; // c1 calculation 273 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 274 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 275 sm_key_t sm_local_random; 276 sm_key_t sm_local_confirm; 277 sm_key_t sm_peer_random; 278 sm_key_t sm_peer_confirm; 279 uint8_t sm_m_addr_type; // address and type can be removed 280 uint8_t sm_s_addr_type; // '' 281 bd_addr_t sm_m_address; // '' 282 bd_addr_t sm_s_address; // '' 283 sm_key_t sm_ltk; 284 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 287 uint8_t sm_peer_qy[32]; // '' 288 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 289 sm_key_t sm_local_nonce; // might be combined with sm_local_random 290 sm_key_t sm_peer_dhkey_check; 291 sm_key_t sm_local_dhkey_check; 292 sm_key_t sm_ra; 293 sm_key_t sm_rb; 294 sm_key_t sm_t; // used for f5 295 sm_key_t sm_mackey; 296 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 297 uint8_t sm_state_vars; 298 #endif 299 300 // Phase 3 301 302 // key distribution, we generate 303 uint16_t sm_local_y; 304 uint16_t sm_local_div; 305 uint16_t sm_local_ediv; 306 uint8_t sm_local_rand[8]; 307 sm_key_t sm_local_ltk; 308 sm_key_t sm_local_csrk; 309 sm_key_t sm_local_irk; 310 // sm_local_address/addr_type not needed 311 312 // key distribution, received from peer 313 uint16_t sm_peer_y; 314 uint16_t sm_peer_div; 315 uint16_t sm_peer_ediv; 316 uint8_t sm_peer_rand[8]; 317 sm_key_t sm_peer_ltk; 318 sm_key_t sm_peer_irk; 319 sm_key_t sm_peer_csrk; 320 uint8_t sm_peer_addr_type; 321 bd_addr_t sm_peer_address; 322 323 } sm_setup_context_t; 324 325 // 326 static sm_setup_context_t the_setup; 327 static sm_setup_context_t * setup = &the_setup; 328 329 // active connection - the one for which the_setup is used for 330 static uint16_t sm_active_connection = 0; 331 332 // @returns 1 if oob data is available 333 // stores oob data in provided 16 byte buffer if not null 334 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 335 336 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 337 static btstack_packet_handler_t sm_client_packet_handler = NULL; 338 339 // horizontal: initiator capabilities 340 // vertial: responder capabilities 341 static const stk_generation_method_t stk_generation_method [5] [5] = { 342 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 343 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 344 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 345 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 346 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 347 }; 348 349 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 350 #ifdef ENABLE_LE_SECURE_CONNECTIONS 351 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 352 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 353 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 354 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 355 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 356 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 357 }; 358 #endif 359 360 static void sm_run(void); 361 static void sm_done_for_handle(hci_con_handle_t con_handle); 362 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 363 static inline int sm_calc_actual_encryption_key_size(int other); 364 static int sm_validate_stk_generation_method(void); 365 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 366 367 static void log_info_hex16(const char * name, uint16_t value){ 368 log_info("%-6s 0x%04x", name, value); 369 } 370 371 // @returns 1 if all bytes are 0 372 static int sm_is_null_random(uint8_t random[8]){ 373 int i; 374 for (i=0; i < 8 ; i++){ 375 if (random[i]) return 0; 376 } 377 return 1; 378 } 379 380 // Key utils 381 static void sm_reset_tk(void){ 382 int i; 383 for (i=0;i<16;i++){ 384 setup->sm_tk[i] = 0; 385 } 386 } 387 388 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 389 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 390 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 391 int i; 392 for (i = max_encryption_size ; i < 16 ; i++){ 393 key[15-i] = 0; 394 } 395 } 396 397 // SMP Timeout implementation 398 399 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 400 // the Security Manager Timer shall be reset and started. 401 // 402 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 403 // 404 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 405 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 406 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 407 // established. 408 409 static void sm_timeout_handler(btstack_timer_source_t * timer){ 410 log_info("SM timeout"); 411 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 412 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 413 sm_done_for_handle(sm_conn->sm_handle); 414 415 // trigger handling of next ready connection 416 sm_run(); 417 } 418 static void sm_timeout_start(sm_connection_t * sm_conn){ 419 btstack_run_loop_remove_timer(&setup->sm_timeout); 420 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 421 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 422 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 423 btstack_run_loop_add_timer(&setup->sm_timeout); 424 } 425 static void sm_timeout_stop(void){ 426 btstack_run_loop_remove_timer(&setup->sm_timeout); 427 } 428 static void sm_timeout_reset(sm_connection_t * sm_conn){ 429 sm_timeout_stop(); 430 sm_timeout_start(sm_conn); 431 } 432 433 // end of sm timeout 434 435 // GAP Random Address updates 436 static gap_random_address_type_t gap_random_adress_type; 437 static btstack_timer_source_t gap_random_address_update_timer; 438 static uint32_t gap_random_adress_update_period; 439 440 static void gap_random_address_trigger(void){ 441 if (rau_state != RAU_IDLE) return; 442 log_info("gap_random_address_trigger"); 443 rau_state = RAU_GET_RANDOM; 444 sm_run(); 445 } 446 447 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 448 log_info("GAP Random Address Update due"); 449 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 450 btstack_run_loop_add_timer(&gap_random_address_update_timer); 451 gap_random_address_trigger(); 452 } 453 454 static void gap_random_address_update_start(void){ 455 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 456 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 457 btstack_run_loop_add_timer(&gap_random_address_update_timer); 458 } 459 460 static void gap_random_address_update_stop(void){ 461 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 462 } 463 464 465 static void sm_random_start(void * context){ 466 sm_random_context = context; 467 hci_send_cmd(&hci_le_rand); 468 } 469 470 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 471 // context is made availabe to aes128 result handler by this 472 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 473 sm_aes128_state = SM_AES128_ACTIVE; 474 sm_key_t key_flipped, plaintext_flipped; 475 reverse_128(key, key_flipped); 476 reverse_128(plaintext, plaintext_flipped); 477 sm_aes128_context = context; 478 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 479 } 480 481 // ah(k,r) helper 482 // r = padding || r 483 // r - 24 bit value 484 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 485 // r'= padding || r 486 memset(r_prime, 0, 16); 487 memcpy(&r_prime[13], r, 3); 488 } 489 490 // d1 helper 491 // d' = padding || r || d 492 // d,r - 16 bit values 493 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 494 // d'= padding || r || d 495 memset(d1_prime, 0, 16); 496 big_endian_store_16(d1_prime, 12, r); 497 big_endian_store_16(d1_prime, 14, d); 498 } 499 500 // dm helper 501 // r’ = padding || r 502 // r - 64 bit value 503 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 504 memset(r_prime, 0, 16); 505 memcpy(&r_prime[8], r, 8); 506 } 507 508 // calculate arguments for first AES128 operation in C1 function 509 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 510 511 // p1 = pres || preq || rat’ || iat’ 512 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 513 // cant octet of pres becomes the most significant octet of p1. 514 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 515 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 516 // p1 is 0x05000800000302070710000001010001." 517 518 sm_key_t p1; 519 reverse_56(pres, &p1[0]); 520 reverse_56(preq, &p1[7]); 521 p1[14] = rat; 522 p1[15] = iat; 523 log_info_key("p1", p1); 524 log_info_key("r", r); 525 526 // t1 = r xor p1 527 int i; 528 for (i=0;i<16;i++){ 529 t1[i] = r[i] ^ p1[i]; 530 } 531 log_info_key("t1", t1); 532 } 533 534 // calculate arguments for second AES128 operation in C1 function 535 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 536 // p2 = padding || ia || ra 537 // "The least significant octet of ra becomes the least significant octet of p2 and 538 // the most significant octet of padding becomes the most significant octet of p2. 539 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 540 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 541 542 sm_key_t p2; 543 memset(p2, 0, 16); 544 memcpy(&p2[4], ia, 6); 545 memcpy(&p2[10], ra, 6); 546 log_info_key("p2", p2); 547 548 // c1 = e(k, t2_xor_p2) 549 int i; 550 for (i=0;i<16;i++){ 551 t3[i] = t2[i] ^ p2[i]; 552 } 553 log_info_key("t3", t3); 554 } 555 556 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 557 log_info_key("r1", r1); 558 log_info_key("r2", r2); 559 memcpy(&r_prime[8], &r2[8], 8); 560 memcpy(&r_prime[0], &r1[8], 8); 561 } 562 563 #ifdef ENABLE_LE_SECURE_CONNECTIONS 564 // Software implementations of crypto toolbox for LE Secure Connection 565 // TODO: replace with code to use AES Engine of HCI Controller 566 typedef uint8_t sm_key24_t[3]; 567 typedef uint8_t sm_key56_t[7]; 568 typedef uint8_t sm_key256_t[32]; 569 570 #if 0 571 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 572 uint32_t rk[RKLENGTH(KEYBITS)]; 573 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 574 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 575 } 576 577 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 578 memcpy(k1, k0, 16); 579 sm_shift_left_by_one_bit_inplace(16, k1); 580 if (k0[0] & 0x80){ 581 k1[15] ^= 0x87; 582 } 583 memcpy(k2, k1, 16); 584 sm_shift_left_by_one_bit_inplace(16, k2); 585 if (k1[0] & 0x80){ 586 k2[15] ^= 0x87; 587 } 588 } 589 590 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 591 sm_key_t k0, k1, k2, zero; 592 memset(zero, 0, 16); 593 594 aes128_calc_cyphertext(key, zero, k0); 595 calc_subkeys(k0, k1, k2); 596 597 int cmac_block_count = (cmac_message_len + 15) / 16; 598 599 // step 3: .. 600 if (cmac_block_count==0){ 601 cmac_block_count = 1; 602 } 603 604 // step 4: set m_last 605 sm_key_t cmac_m_last; 606 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 607 int i; 608 if (sm_cmac_last_block_complete){ 609 for (i=0;i<16;i++){ 610 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 611 } 612 } else { 613 int valid_octets_in_last_block = cmac_message_len & 0x0f; 614 for (i=0;i<16;i++){ 615 if (i < valid_octets_in_last_block){ 616 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 617 continue; 618 } 619 if (i == valid_octets_in_last_block){ 620 cmac_m_last[i] = 0x80 ^ k2[i]; 621 continue; 622 } 623 cmac_m_last[i] = k2[i]; 624 } 625 } 626 627 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 628 // LOG_KEY(cmac_m_last); 629 630 // Step 5 631 sm_key_t cmac_x; 632 memset(cmac_x, 0, 16); 633 634 // Step 6 635 sm_key_t sm_cmac_y; 636 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 637 for (i=0;i<16;i++){ 638 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 639 } 640 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 641 } 642 for (i=0;i<16;i++){ 643 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 644 } 645 646 // Step 7 647 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 648 } 649 #endif 650 651 #if 0 652 // 653 // Link Key Conversion Function h6 654 // 655 // h6(W, keyID) = AES-CMACW(keyID) 656 // - W is 128 bits 657 // - keyID is 32 bits 658 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 659 uint8_t key_id_buffer[4]; 660 big_endian_store_32(key_id_buffer, 0, key_id); 661 aes_cmac(res, w, key_id_buffer, 4); 662 } 663 #endif 664 #endif 665 666 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){ 667 event[0] = type; 668 event[1] = event_size - 2; 669 little_endian_store_16(event, 2, con_handle); 670 event[4] = addr_type; 671 reverse_bd_addr(address, &event[5]); 672 } 673 674 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 675 if (sm_client_packet_handler) { 676 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 677 } 678 // dispatch to all event handlers 679 btstack_linked_list_iterator_t it; 680 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 681 while (btstack_linked_list_iterator_has_next(&it)){ 682 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 683 entry->callback(packet_type, 0, packet, size); 684 } 685 } 686 687 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 688 uint8_t event[11]; 689 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 690 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 691 } 692 693 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){ 694 uint8_t event[15]; 695 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 696 little_endian_store_32(event, 11, passkey); 697 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 698 } 699 700 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){ 701 uint8_t event[13]; 702 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 703 little_endian_store_16(event, 11, index); 704 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 705 } 706 707 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){ 708 709 uint8_t event[18]; 710 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 711 event[11] = result; 712 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 713 } 714 715 // decide on stk generation based on 716 // - pairing request 717 // - io capabilities 718 // - OOB data availability 719 static void sm_setup_tk(void){ 720 721 // default: just works 722 setup->sm_stk_generation_method = JUST_WORKS; 723 724 #ifdef ENABLE_LE_SECURE_CONNECTIONS 725 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 726 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 727 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 728 memset(setup->sm_ra, 0, 16); 729 memset(setup->sm_rb, 0, 16); 730 #else 731 setup->sm_use_secure_connections = 0; 732 #endif 733 734 // If both devices have not set the MITM option in the Authentication Requirements 735 // Flags, then the IO capabilities shall be ignored and the Just Works association 736 // model shall be used. 737 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 738 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 739 log_info("SM: MITM not required by both -> JUST WORKS"); 740 return; 741 } 742 743 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 744 745 // If both devices have out of band authentication data, then the Authentication 746 // Requirements Flags shall be ignored when selecting the pairing method and the 747 // Out of Band pairing method shall be used. 748 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 749 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 750 log_info("SM: have OOB data"); 751 log_info_key("OOB", setup->sm_tk); 752 setup->sm_stk_generation_method = OOB; 753 return; 754 } 755 756 // Reset TK as it has been setup in sm_init_setup 757 sm_reset_tk(); 758 759 // Also use just works if unknown io capabilites 760 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)){ 761 return; 762 } 763 764 // Otherwise the IO capabilities of the devices shall be used to determine the 765 // pairing method as defined in Table 2.4. 766 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 767 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 768 769 #ifdef ENABLE_LE_SECURE_CONNECTIONS 770 // table not define by default 771 if (setup->sm_use_secure_connections){ 772 generation_method = stk_generation_method_with_secure_connection; 773 } 774 #endif 775 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)]; 776 777 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 778 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); 779 } 780 781 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 782 int flags = 0; 783 if (key_set & SM_KEYDIST_ENC_KEY){ 784 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 785 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 786 } 787 if (key_set & SM_KEYDIST_ID_KEY){ 788 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 789 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 790 } 791 if (key_set & SM_KEYDIST_SIGN){ 792 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 793 } 794 return flags; 795 } 796 797 static void sm_setup_key_distribution(uint8_t key_set){ 798 setup->sm_key_distribution_received_set = 0; 799 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 800 } 801 802 // CSRK Key Lookup 803 804 805 static int sm_address_resolution_idle(void){ 806 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 807 } 808 809 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){ 810 memcpy(sm_address_resolution_address, addr, 6); 811 sm_address_resolution_addr_type = addr_type; 812 sm_address_resolution_test = 0; 813 sm_address_resolution_mode = mode; 814 sm_address_resolution_context = context; 815 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 816 } 817 818 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 819 // check if already in list 820 btstack_linked_list_iterator_t it; 821 sm_lookup_entry_t * entry; 822 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 823 while(btstack_linked_list_iterator_has_next(&it)){ 824 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 825 if (entry->address_type != address_type) continue; 826 if (memcmp(entry->address, address, 6)) continue; 827 // already in list 828 return BTSTACK_BUSY; 829 } 830 entry = btstack_memory_sm_lookup_entry_get(); 831 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 832 entry->address_type = (bd_addr_type_t) address_type; 833 memcpy(entry->address, address, 6); 834 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 835 sm_run(); 836 return 0; 837 } 838 839 // CMAC Implementation using AES128 engine 840 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 841 int i; 842 int carry = 0; 843 for (i=len-1; i >= 0 ; i--){ 844 int new_carry = data[i] >> 7; 845 data[i] = data[i] << 1 | carry; 846 carry = new_carry; 847 } 848 } 849 850 // 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 851 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 852 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 853 } 854 static inline void dkg_next_state(void){ 855 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 856 } 857 static inline void rau_next_state(void){ 858 rau_state = (random_address_update_t) (((int)rau_state) + 1); 859 } 860 861 // CMAC calculation using AES Engine 862 863 static inline void sm_cmac_next_state(void){ 864 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 865 } 866 867 static int sm_cmac_last_block_complete(void){ 868 if (sm_cmac_message_len == 0) return 0; 869 return (sm_cmac_message_len & 0x0f) == 0; 870 } 871 872 static inline uint8_t sm_cmac_message_get_byte(uint16_t offset){ 873 if (offset >= sm_cmac_message_len) { 874 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 875 return 0; 876 } 877 878 offset = sm_cmac_message_len - 1 - offset; 879 880 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 881 if (offset < 3){ 882 return sm_cmac_header[offset]; 883 } 884 int actual_message_len_incl_header = sm_cmac_message_len - 4; 885 if (offset < actual_message_len_incl_header){ 886 return sm_cmac_message[offset - 3]; 887 } 888 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 889 } 890 891 // generic cmac calculation 892 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])){ 893 // Generalized CMAC 894 memcpy(sm_cmac_k, key, 16); 895 memset(sm_cmac_x, 0, 16); 896 sm_cmac_block_current = 0; 897 sm_cmac_message_len = message_len; 898 sm_cmac_done_handler = done_callback; 899 sm_cmac_get_byte = get_byte_callback; 900 901 // step 2: n := ceil(len/const_Bsize); 902 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 903 904 // step 3: .. 905 if (sm_cmac_block_count==0){ 906 sm_cmac_block_count = 1; 907 } 908 log_info("sm_cmac_connection %p", sm_cmac_connection); 909 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 910 911 // first, we need to compute l for k1, k2, and m_last 912 sm_cmac_state = CMAC_CALC_SUBKEYS; 913 914 // let's go 915 sm_run(); 916 } 917 918 // cmac for ATT Message signing 919 void sm_cmac_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)){ 920 // ATT Message Signing 921 sm_cmac_header[0] = opcode; 922 little_endian_store_16(sm_cmac_header, 1, con_handle); 923 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 924 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 925 sm_cmac_message = message; 926 sm_cmac_general_start(k, total_message_len, &sm_cmac_message_get_byte, done_handler); 927 } 928 929 int sm_cmac_ready(void){ 930 return sm_cmac_state == CMAC_IDLE; 931 } 932 933 static void sm_cmac_handle_aes_engine_ready(void){ 934 switch (sm_cmac_state){ 935 case CMAC_CALC_SUBKEYS: { 936 sm_key_t const_zero; 937 memset(const_zero, 0, 16); 938 sm_cmac_next_state(); 939 sm_aes128_start(sm_cmac_k, const_zero, NULL); 940 break; 941 } 942 case CMAC_CALC_MI: { 943 int j; 944 sm_key_t y; 945 for (j=0;j<16;j++){ 946 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 947 } 948 sm_cmac_block_current++; 949 sm_cmac_next_state(); 950 sm_aes128_start(sm_cmac_k, y, NULL); 951 break; 952 } 953 case CMAC_CALC_MLAST: { 954 int i; 955 sm_key_t y; 956 for (i=0;i<16;i++){ 957 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 958 } 959 log_info_key("Y", y); 960 sm_cmac_block_current++; 961 sm_cmac_next_state(); 962 sm_aes128_start(sm_cmac_k, y, NULL); 963 break; 964 } 965 default: 966 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 967 break; 968 } 969 } 970 971 static void sm_cmac_handle_encryption_result(sm_key_t data){ 972 switch (sm_cmac_state){ 973 case CMAC_W4_SUBKEYS: { 974 sm_key_t k1; 975 memcpy(k1, data, 16); 976 sm_shift_left_by_one_bit_inplace(16, k1); 977 if (data[0] & 0x80){ 978 k1[15] ^= 0x87; 979 } 980 sm_key_t k2; 981 memcpy(k2, k1, 16); 982 sm_shift_left_by_one_bit_inplace(16, k2); 983 if (k1[0] & 0x80){ 984 k2[15] ^= 0x87; 985 } 986 987 log_info_key("k", sm_cmac_k); 988 log_info_key("k1", k1); 989 log_info_key("k2", k2); 990 991 // step 4: set m_last 992 int i; 993 if (sm_cmac_last_block_complete()){ 994 for (i=0;i<16;i++){ 995 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 996 } 997 } else { 998 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 999 for (i=0;i<16;i++){ 1000 if (i < valid_octets_in_last_block){ 1001 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1002 continue; 1003 } 1004 if (i == valid_octets_in_last_block){ 1005 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1006 continue; 1007 } 1008 sm_cmac_m_last[i] = k2[i]; 1009 } 1010 } 1011 1012 // next 1013 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1014 break; 1015 } 1016 case CMAC_W4_MI: 1017 memcpy(sm_cmac_x, data, 16); 1018 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1019 break; 1020 case CMAC_W4_MLAST: 1021 // done 1022 log_info("Setting CMAC Engine to IDLE"); 1023 sm_cmac_state = CMAC_IDLE; 1024 log_info_key("CMAC", data); 1025 sm_cmac_done_handler(data); 1026 break; 1027 default: 1028 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1029 break; 1030 } 1031 } 1032 1033 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1034 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1035 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1036 switch (setup->sm_stk_generation_method){ 1037 case PK_RESP_INPUT: 1038 if (sm_conn->sm_role){ 1039 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1040 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1041 } else { 1042 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)); 1043 } 1044 break; 1045 case PK_INIT_INPUT: 1046 if (sm_conn->sm_role){ 1047 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)); 1048 } else { 1049 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1050 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1051 } 1052 break; 1053 case OK_BOTH_INPUT: 1054 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1055 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1056 break; 1057 case NK_BOTH_INPUT: 1058 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1059 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)); 1060 break; 1061 case JUST_WORKS: 1062 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1063 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1064 break; 1065 case OOB: 1066 // client already provided OOB data, let's skip notification. 1067 break; 1068 } 1069 } 1070 1071 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1072 int recv_flags; 1073 if (sm_conn->sm_role){ 1074 // slave / responder 1075 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1076 } else { 1077 // master / initiator 1078 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1079 } 1080 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1081 return recv_flags == setup->sm_key_distribution_received_set; 1082 } 1083 1084 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1085 if (sm_active_connection == con_handle){ 1086 sm_timeout_stop(); 1087 sm_active_connection = 0; 1088 log_info("sm: connection 0x%x released setup context", con_handle); 1089 } 1090 } 1091 1092 static int sm_key_distribution_flags_for_auth_req(void){ 1093 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1094 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1095 // encryption information only if bonding requested 1096 flags |= SM_KEYDIST_ENC_KEY; 1097 } 1098 return flags; 1099 } 1100 1101 static void sm_init_setup(sm_connection_t * sm_conn){ 1102 1103 // fill in sm setup 1104 setup->sm_state_vars = 0; 1105 sm_reset_tk(); 1106 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1107 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1108 1109 // query client for OOB data 1110 int have_oob_data = 0; 1111 if (sm_get_oob_data) { 1112 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1113 } 1114 1115 sm_pairing_packet_t * local_packet; 1116 if (sm_conn->sm_role){ 1117 // slave 1118 local_packet = &setup->sm_s_pres; 1119 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1120 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1121 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1122 } else { 1123 // master 1124 local_packet = &setup->sm_m_preq; 1125 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1126 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1127 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1128 1129 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1130 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1131 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1132 } 1133 1134 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1135 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1136 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1137 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1138 } 1139 1140 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1141 1142 sm_pairing_packet_t * remote_packet; 1143 int remote_key_request; 1144 if (sm_conn->sm_role){ 1145 // slave / responder 1146 remote_packet = &setup->sm_m_preq; 1147 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1148 } else { 1149 // master / initiator 1150 remote_packet = &setup->sm_s_pres; 1151 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1152 } 1153 1154 // check key size 1155 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1156 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1157 1158 // decide on STK generation method 1159 sm_setup_tk(); 1160 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1161 1162 // check if STK generation method is acceptable by client 1163 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1164 1165 // identical to responder 1166 sm_setup_key_distribution(remote_key_request); 1167 1168 // JUST WORKS doens't provide authentication 1169 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1170 1171 return 0; 1172 } 1173 1174 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1175 1176 // cache and reset context 1177 int matched_device_id = sm_address_resolution_test; 1178 address_resolution_mode_t mode = sm_address_resolution_mode; 1179 void * context = sm_address_resolution_context; 1180 1181 // reset context 1182 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1183 sm_address_resolution_context = NULL; 1184 sm_address_resolution_test = -1; 1185 hci_con_handle_t con_handle = 0; 1186 1187 sm_connection_t * sm_connection; 1188 uint16_t ediv; 1189 switch (mode){ 1190 case ADDRESS_RESOLUTION_GENERAL: 1191 break; 1192 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1193 sm_connection = (sm_connection_t *) context; 1194 con_handle = sm_connection->sm_handle; 1195 switch (event){ 1196 case ADDRESS_RESOLUTION_SUCEEDED: 1197 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1198 sm_connection->sm_le_db_index = matched_device_id; 1199 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1200 if (sm_connection->sm_role) break; 1201 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1202 sm_connection->sm_security_request_received = 0; 1203 sm_connection->sm_bonding_requested = 0; 1204 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1205 if (ediv){ 1206 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1207 } else { 1208 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1209 } 1210 break; 1211 case ADDRESS_RESOLUTION_FAILED: 1212 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1213 if (sm_connection->sm_role) break; 1214 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1215 sm_connection->sm_security_request_received = 0; 1216 sm_connection->sm_bonding_requested = 0; 1217 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1218 break; 1219 } 1220 break; 1221 default: 1222 break; 1223 } 1224 1225 switch (event){ 1226 case ADDRESS_RESOLUTION_SUCEEDED: 1227 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1228 break; 1229 case ADDRESS_RESOLUTION_FAILED: 1230 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1231 break; 1232 } 1233 } 1234 1235 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1236 1237 int le_db_index = -1; 1238 1239 // lookup device based on IRK 1240 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1241 int i; 1242 for (i=0; i < le_device_db_count(); i++){ 1243 sm_key_t irk; 1244 bd_addr_t address; 1245 int address_type; 1246 le_device_db_info(i, &address_type, address, irk); 1247 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1248 log_info("sm: device found for IRK, updating"); 1249 le_db_index = i; 1250 break; 1251 } 1252 } 1253 } 1254 1255 // if not found, lookup via public address if possible 1256 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1257 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1258 int i; 1259 for (i=0; i < le_device_db_count(); i++){ 1260 bd_addr_t address; 1261 int address_type; 1262 le_device_db_info(i, &address_type, address, NULL); 1263 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1264 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1265 log_info("sm: device found for public address, updating"); 1266 le_db_index = i; 1267 break; 1268 } 1269 } 1270 } 1271 1272 // if not found, add to db 1273 if (le_db_index < 0) { 1274 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1275 } 1276 1277 if (le_db_index >= 0){ 1278 le_device_db_local_counter_set(le_db_index, 0); 1279 1280 // store local CSRK 1281 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1282 log_info("sm: store local CSRK"); 1283 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1284 le_device_db_local_counter_set(le_db_index, 0); 1285 } 1286 1287 // store remote CSRK 1288 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1289 log_info("sm: store remote CSRK"); 1290 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1291 le_device_db_remote_counter_set(le_db_index, 0); 1292 } 1293 1294 // store encryption information 1295 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1296 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1297 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1298 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1299 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1300 } 1301 } 1302 1303 // keep le_db_index 1304 sm_conn->sm_le_db_index = le_db_index; 1305 } 1306 1307 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1308 setup->sm_pairing_failed_reason = reason; 1309 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1310 } 1311 1312 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1313 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1314 } 1315 1316 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1317 1318 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1319 1320 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1321 if (sm_conn->sm_role){ 1322 // Responder 1323 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1324 } else { 1325 // Initiator role 1326 switch (setup->sm_stk_generation_method){ 1327 case JUST_WORKS: 1328 sm_sc_prepare_dhkey_check(sm_conn); 1329 break; 1330 1331 case NK_BOTH_INPUT: 1332 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1333 break; 1334 case PK_INIT_INPUT: 1335 case PK_RESP_INPUT: 1336 case OK_BOTH_INPUT: 1337 if (setup->sm_passkey_bit < 20) { 1338 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1339 } else { 1340 sm_sc_prepare_dhkey_check(sm_conn); 1341 } 1342 break; 1343 case OOB: 1344 // TODO: implement SC OOB 1345 break; 1346 } 1347 } 1348 } 1349 1350 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1351 return sm_cmac_sc_buffer[offset]; 1352 } 1353 1354 static void sm_sc_cmac_done(uint8_t * hash){ 1355 log_info("sm_sc_cmac_done: "); 1356 log_info_hexdump(hash, 16); 1357 1358 sm_connection_t * sm_conn = sm_cmac_connection; 1359 sm_cmac_connection = NULL; 1360 1361 switch (sm_conn->sm_engine_state){ 1362 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1363 memcpy(setup->sm_local_confirm, hash, 16); 1364 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1365 break; 1366 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1367 // check 1368 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1369 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1370 break; 1371 } 1372 sm_sc_state_after_receiving_random(sm_conn); 1373 break; 1374 case SM_SC_W4_CALCULATE_G2: { 1375 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1376 big_endian_store_32(setup->sm_tk, 12, vab); 1377 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1378 sm_trigger_user_response(sm_conn); 1379 break; 1380 } 1381 case SM_SC_W4_CALCULATE_F5_SALT: 1382 memcpy(setup->sm_t, hash, 16); 1383 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1384 break; 1385 case SM_SC_W4_CALCULATE_F5_MACKEY: 1386 memcpy(setup->sm_mackey, hash, 16); 1387 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1388 break; 1389 case SM_SC_W4_CALCULATE_F5_LTK: 1390 memcpy(setup->sm_ltk, hash, 16); 1391 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1392 break; 1393 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1394 memcpy(setup->sm_local_dhkey_check, hash, 16); 1395 if (sm_conn->sm_role){ 1396 // responder 1397 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1398 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1399 } else { 1400 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1401 } 1402 } else { 1403 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1404 } 1405 break; 1406 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1407 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1408 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1409 break; 1410 } 1411 if (sm_conn->sm_role){ 1412 // responder 1413 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1414 } else { 1415 // initiator 1416 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1417 } 1418 break; 1419 default: 1420 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1421 break; 1422 } 1423 sm_run(); 1424 } 1425 1426 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){ 1427 const uint16_t message_len = 65; 1428 sm_cmac_connection = sm_conn; 1429 memcpy(sm_cmac_sc_buffer, u, 32); 1430 memcpy(sm_cmac_sc_buffer+32, v, 32); 1431 sm_cmac_sc_buffer[64] = z; 1432 log_info("f4 key"); 1433 log_info_hexdump(x, 16); 1434 log_info("f4 message"); 1435 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1436 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1437 } 1438 1439 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1440 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1441 static const uint8_t f5_length[] = { 0x01, 0x00}; 1442 1443 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1444 #ifdef USE_MBEDTLS_FOR_ECDH 1445 // da * Pb 1446 mbedtls_ecp_group grp; 1447 mbedtls_ecp_group_init( &grp ); 1448 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1449 mbedtls_ecp_point Q; 1450 mbedtls_ecp_point_init( &Q ); 1451 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1452 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1453 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1454 mbedtls_ecp_point DH; 1455 mbedtls_ecp_point_init( &DH ); 1456 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1457 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1458 #endif 1459 log_info("dhkey"); 1460 log_info_hexdump(dhkey, 32); 1461 } 1462 1463 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1464 // calculate DHKEY 1465 sm_key256_t dhkey; 1466 sm_sc_calculate_dhkey(dhkey); 1467 1468 // calculate salt for f5 1469 const uint16_t message_len = 32; 1470 sm_cmac_connection = sm_conn; 1471 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1472 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1473 } 1474 1475 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){ 1476 const uint16_t message_len = 53; 1477 sm_cmac_connection = sm_conn; 1478 1479 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1480 sm_cmac_sc_buffer[0] = 0; 1481 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1482 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1483 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1484 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1485 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1486 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1487 log_info("f5 key"); 1488 log_info_hexdump(t, 16); 1489 log_info("f5 message for MacKey"); 1490 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1491 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1492 } 1493 1494 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1495 sm_key56_t bd_addr_master, bd_addr_slave; 1496 bd_addr_master[0] = setup->sm_m_addr_type; 1497 bd_addr_slave[0] = setup->sm_s_addr_type; 1498 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1499 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1500 if (sm_conn->sm_role){ 1501 // responder 1502 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1503 } else { 1504 // initiator 1505 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1506 } 1507 } 1508 1509 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1510 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1511 const uint16_t message_len = 53; 1512 sm_cmac_connection = sm_conn; 1513 sm_cmac_sc_buffer[0] = 1; 1514 // 1..52 setup before 1515 log_info("f5 key"); 1516 log_info_hexdump(t, 16); 1517 log_info("f5 message for LTK"); 1518 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1519 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1520 } 1521 1522 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1523 f5_ltk(sm_conn, setup->sm_t); 1524 } 1525 1526 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){ 1527 const uint16_t message_len = 65; 1528 sm_cmac_connection = sm_conn; 1529 memcpy(sm_cmac_sc_buffer, n1, 16); 1530 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1531 memcpy(sm_cmac_sc_buffer+32, r, 16); 1532 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1533 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1534 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1535 log_info("f6 key"); 1536 log_info_hexdump(w, 16); 1537 log_info("f6 message"); 1538 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1539 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1540 } 1541 1542 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1543 // - U is 256 bits 1544 // - V is 256 bits 1545 // - X is 128 bits 1546 // - Y is 128 bits 1547 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){ 1548 const uint16_t message_len = 80; 1549 sm_cmac_connection = sm_conn; 1550 memcpy(sm_cmac_sc_buffer, u, 32); 1551 memcpy(sm_cmac_sc_buffer+32, v, 32); 1552 memcpy(sm_cmac_sc_buffer+64, y, 16); 1553 log_info("g2 key"); 1554 log_info_hexdump(x, 16); 1555 log_info("g2 message"); 1556 log_info_hexdump(sm_cmac_sc_buffer, sizeof(sm_cmac_sc_buffer)); 1557 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1558 } 1559 1560 static void g2_calculate_engine(sm_connection_t * sm_conn) { 1561 // calc Va if numeric comparison 1562 uint8_t value[32]; 1563 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1564 if (sm_conn->sm_role){ 1565 // responder 1566 g2_engine(sm_conn, setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce);; 1567 } else { 1568 // initiator 1569 g2_engine(sm_conn, value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1570 } 1571 } 1572 1573 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1574 1575 // TODO: use random generator to generate nonce 1576 1577 // generate 128-bit nonce 1578 int i; 1579 for (i=0;i<16;i++){ 1580 setup->sm_local_nonce[i] = rand() & 0xff; 1581 } 1582 1583 uint8_t z = 0; 1584 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1585 // some form of passkey 1586 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1587 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1588 setup->sm_passkey_bit++; 1589 } 1590 #ifdef USE_MBEDTLS_FOR_ECDH 1591 uint8_t local_qx[32]; 1592 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1593 #endif 1594 f4_engine(sm_conn, local_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1595 } 1596 1597 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1598 uint8_t z = 0; 1599 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1600 // some form of passkey 1601 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1602 // sm_passkey_bit was increased before sending confirm value 1603 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1604 } 1605 #ifdef USE_MBEDTLS_FOR_ECDH 1606 uint8_t local_qx[32]; 1607 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1608 #endif 1609 f4_engine(sm_conn, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 1610 } 1611 1612 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1613 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1614 } 1615 1616 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1617 // calculate DHKCheck 1618 sm_key56_t bd_addr_master, bd_addr_slave; 1619 bd_addr_master[0] = setup->sm_m_addr_type; 1620 bd_addr_slave[0] = setup->sm_s_addr_type; 1621 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1622 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1623 uint8_t iocap_a[3]; 1624 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1625 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1626 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1627 uint8_t iocap_b[3]; 1628 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1629 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1630 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1631 if (sm_conn->sm_role){ 1632 // responder 1633 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); 1634 } else { 1635 // initiator 1636 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); 1637 } 1638 } 1639 1640 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1641 // validate E = f6() 1642 sm_key56_t bd_addr_master, bd_addr_slave; 1643 bd_addr_master[0] = setup->sm_m_addr_type; 1644 bd_addr_slave[0] = setup->sm_s_addr_type; 1645 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1646 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1647 1648 uint8_t iocap_a[3]; 1649 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1650 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1651 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1652 uint8_t iocap_b[3]; 1653 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1654 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1655 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1656 if (sm_conn->sm_role){ 1657 // responder 1658 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); 1659 } else { 1660 // initiator 1661 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); 1662 } 1663 } 1664 #endif 1665 1666 1667 static void sm_run(void){ 1668 1669 btstack_linked_list_iterator_t it; 1670 1671 // assert that we can send at least commands 1672 if (!hci_can_send_command_packet_now()) return; 1673 1674 // 1675 // non-connection related behaviour 1676 // 1677 1678 // distributed key generation 1679 switch (dkg_state){ 1680 case DKG_CALC_IRK: 1681 // already busy? 1682 if (sm_aes128_state == SM_AES128_IDLE) { 1683 // IRK = d1(IR, 1, 0) 1684 sm_key_t d1_prime; 1685 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1686 dkg_next_state(); 1687 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1688 return; 1689 } 1690 break; 1691 case DKG_CALC_DHK: 1692 // already busy? 1693 if (sm_aes128_state == SM_AES128_IDLE) { 1694 // DHK = d1(IR, 3, 0) 1695 sm_key_t d1_prime; 1696 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1697 dkg_next_state(); 1698 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1699 return; 1700 } 1701 break; 1702 default: 1703 break; 1704 } 1705 1706 #ifdef USE_MBEDTLS_FOR_ECDH 1707 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1708 sm_random_start(NULL); 1709 return; 1710 } 1711 #endif 1712 1713 // random address updates 1714 switch (rau_state){ 1715 case RAU_GET_RANDOM: 1716 rau_next_state(); 1717 sm_random_start(NULL); 1718 return; 1719 case RAU_GET_ENC: 1720 // already busy? 1721 if (sm_aes128_state == SM_AES128_IDLE) { 1722 sm_key_t r_prime; 1723 sm_ah_r_prime(sm_random_address, r_prime); 1724 rau_next_state(); 1725 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1726 return; 1727 } 1728 break; 1729 case RAU_SET_ADDRESS: 1730 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1731 rau_state = RAU_IDLE; 1732 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1733 return; 1734 default: 1735 break; 1736 } 1737 1738 // CMAC 1739 switch (sm_cmac_state){ 1740 case CMAC_CALC_SUBKEYS: 1741 case CMAC_CALC_MI: 1742 case CMAC_CALC_MLAST: 1743 // already busy? 1744 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1745 sm_cmac_handle_aes_engine_ready(); 1746 return; 1747 default: 1748 break; 1749 } 1750 1751 // CSRK Lookup 1752 // -- if csrk lookup ready, find connection that require csrk lookup 1753 if (sm_address_resolution_idle()){ 1754 hci_connections_get_iterator(&it); 1755 while(btstack_linked_list_iterator_has_next(&it)){ 1756 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1757 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1758 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1759 // and start lookup 1760 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); 1761 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1762 break; 1763 } 1764 } 1765 } 1766 1767 // -- if csrk lookup ready, resolved addresses for received addresses 1768 if (sm_address_resolution_idle()) { 1769 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1770 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1771 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1772 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1773 btstack_memory_sm_lookup_entry_free(entry); 1774 } 1775 } 1776 1777 // -- Continue with CSRK device lookup by public or resolvable private address 1778 if (!sm_address_resolution_idle()){ 1779 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1780 while (sm_address_resolution_test < le_device_db_count()){ 1781 int addr_type; 1782 bd_addr_t addr; 1783 sm_key_t irk; 1784 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1785 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1786 1787 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1788 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1789 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1790 break; 1791 } 1792 1793 if (sm_address_resolution_addr_type == 0){ 1794 sm_address_resolution_test++; 1795 continue; 1796 } 1797 1798 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1799 1800 log_info("LE Device Lookup: calculate AH"); 1801 log_info_key("IRK", irk); 1802 1803 sm_key_t r_prime; 1804 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1805 sm_address_resolution_ah_calculation_active = 1; 1806 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1807 return; 1808 } 1809 1810 if (sm_address_resolution_test >= le_device_db_count()){ 1811 log_info("LE Device Lookup: not found"); 1812 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1813 } 1814 } 1815 1816 1817 // 1818 // active connection handling 1819 // -- use loop to handle next connection if lock on setup context is released 1820 1821 while (1) { 1822 1823 // Find connections that requires setup context and make active if no other is locked 1824 hci_connections_get_iterator(&it); 1825 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1826 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1827 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1828 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1829 int done = 1; 1830 int err; 1831 int encryption_key_size; 1832 int authenticated; 1833 int authorized; 1834 switch (sm_connection->sm_engine_state) { 1835 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1836 // send packet if possible, 1837 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1838 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1839 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1840 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1841 } else { 1842 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1843 } 1844 // don't lock setup context yet 1845 done = 0; 1846 break; 1847 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1848 sm_init_setup(sm_connection); 1849 // recover pairing request 1850 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1851 err = sm_stk_generation_init(sm_connection); 1852 if (err){ 1853 setup->sm_pairing_failed_reason = err; 1854 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1855 break; 1856 } 1857 sm_timeout_start(sm_connection); 1858 // generate random number first, if we need to show passkey 1859 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1860 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1861 break; 1862 } 1863 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1864 break; 1865 case SM_INITIATOR_PH0_HAS_LTK: 1866 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1867 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1868 &encryption_key_size, &authenticated, &authorized); 1869 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1870 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1871 sm_connection->sm_connection_authenticated = authenticated; 1872 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1873 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1874 break; 1875 case SM_RESPONDER_PH0_RECEIVED_LTK: 1876 // re-establish previously used LTK using Rand and EDIV 1877 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1878 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1879 // re-establish used key encryption size 1880 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1881 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1882 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1883 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1884 log_info("sm: received ltk request with key size %u, authenticated %u", 1885 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1886 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1887 break; 1888 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1889 sm_init_setup(sm_connection); 1890 sm_timeout_start(sm_connection); 1891 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1892 break; 1893 default: 1894 done = 0; 1895 break; 1896 } 1897 if (done){ 1898 sm_active_connection = sm_connection->sm_handle; 1899 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1900 } 1901 } 1902 1903 // 1904 // active connection handling 1905 // 1906 1907 if (sm_active_connection == 0) return; 1908 1909 // assert that we could send a SM PDU - not needed for all of the following 1910 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1911 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1912 return; 1913 } 1914 1915 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1916 if (!connection) return; 1917 1918 sm_key_t plaintext; 1919 int key_distribution_flags; 1920 1921 log_info("sm_run: state %u", connection->sm_engine_state); 1922 1923 // responding state 1924 switch (connection->sm_engine_state){ 1925 1926 // general 1927 case SM_GENERAL_SEND_PAIRING_FAILED: { 1928 uint8_t buffer[2]; 1929 buffer[0] = SM_CODE_PAIRING_FAILED; 1930 buffer[1] = setup->sm_pairing_failed_reason; 1931 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1932 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1933 sm_done_for_handle(connection->sm_handle); 1934 break; 1935 } 1936 1937 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1938 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1939 if (!sm_cmac_ready()) break; 1940 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1941 sm_sc_calculate_local_confirm(connection); 1942 break; 1943 1944 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 1945 if (!sm_cmac_ready()) break; 1946 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 1947 sm_sc_calculate_remote_confirm(connection); 1948 break; 1949 1950 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 1951 if (!sm_cmac_ready()) break; 1952 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 1953 sm_sc_calculate_f6_for_dhkey_check(connection); 1954 break; 1955 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1956 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1957 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 1958 break; 1959 case SM_SC_W2_CALCULATE_F5_SALT: 1960 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 1961 f5_calculate_salt(connection); 1962 break; 1963 case SM_SC_W2_CALCULATE_F5_MACKEY: 1964 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 1965 f5_calculate_mackey(connection); 1966 break; 1967 case SM_SC_W2_CALCULATE_F5_LTK: 1968 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 1969 f5_calculate_ltk(connection); 1970 break; 1971 case SM_SC_W2_CALCULATE_G2: 1972 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 1973 g2_calculate_engine(connection); 1974 break; 1975 1976 #endif 1977 // initiator side 1978 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1979 sm_key_t peer_ltk_flipped; 1980 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1981 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1982 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1983 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1984 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1985 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1986 return; 1987 } 1988 1989 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1990 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1991 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1992 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1993 sm_timeout_reset(connection); 1994 break; 1995 1996 // responder side 1997 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1998 connection->sm_engine_state = SM_RESPONDER_IDLE; 1999 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2000 return; 2001 2002 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2003 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2004 uint8_t buffer[65]; 2005 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2006 // 2007 #ifdef USE_MBEDTLS_FOR_ECDH 2008 uint8_t value[32]; 2009 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2010 reverse_256(value, &buffer[1]); 2011 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 2012 reverse_256(value, &buffer[33]); 2013 #endif 2014 2015 // stk generation method 2016 // passkey entry: notify app to show passkey or to request passkey 2017 switch (setup->sm_stk_generation_method){ 2018 case JUST_WORKS: 2019 case NK_BOTH_INPUT: 2020 if (connection->sm_role){ 2021 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2022 } else { 2023 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2024 } 2025 break; 2026 case PK_INIT_INPUT: 2027 case PK_RESP_INPUT: 2028 case OK_BOTH_INPUT: 2029 // hack for testing: assume user entered '000000' 2030 // memset(setup->sm_tk, 0, 16); 2031 memcpy(setup->sm_ra, setup->sm_tk, 16); 2032 memcpy(setup->sm_rb, setup->sm_tk, 16); 2033 setup->sm_passkey_bit = 0; 2034 if (connection->sm_role){ 2035 // responder 2036 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2037 } else { 2038 // initiator 2039 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2040 } 2041 sm_trigger_user_response(connection); 2042 break; 2043 case OOB: 2044 // TODO: implement SC OOB 2045 break; 2046 } 2047 2048 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2049 sm_timeout_reset(connection); 2050 break; 2051 } 2052 case SM_SC_SEND_CONFIRMATION: { 2053 uint8_t buffer[17]; 2054 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2055 reverse_128(setup->sm_local_confirm, &buffer[1]); 2056 if (connection->sm_role){ 2057 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2058 } else { 2059 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2060 } 2061 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2062 sm_timeout_reset(connection); 2063 break; 2064 } 2065 case SM_SC_SEND_PAIRING_RANDOM: { 2066 uint8_t buffer[17]; 2067 buffer[0] = SM_CODE_PAIRING_RANDOM; 2068 reverse_128(setup->sm_local_nonce, &buffer[1]); 2069 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2070 if (connection->sm_role){ 2071 // responder 2072 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2073 } else { 2074 // initiator 2075 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2076 } 2077 } else { 2078 if (connection->sm_role){ 2079 // responder 2080 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2081 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2082 } else { 2083 sm_sc_prepare_dhkey_check(connection); 2084 } 2085 } else { 2086 // initiator 2087 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2088 } 2089 } 2090 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2091 sm_timeout_reset(connection); 2092 break; 2093 } 2094 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2095 uint8_t buffer[17]; 2096 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2097 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2098 2099 if (connection->sm_role){ 2100 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2101 } else { 2102 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2103 } 2104 2105 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2106 sm_timeout_reset(connection); 2107 break; 2108 } 2109 2110 #endif 2111 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2112 // echo initiator for now 2113 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2114 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2115 2116 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2117 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2118 if (setup->sm_use_secure_connections){ 2119 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2120 // skip LTK/EDIV for SC 2121 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2122 } 2123 #endif 2124 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); 2125 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); 2126 2127 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2128 sm_timeout_reset(connection); 2129 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2130 if (setup->sm_stk_generation_method == JUST_WORKS){ 2131 sm_trigger_user_response(connection); 2132 } 2133 return; 2134 2135 case SM_PH2_SEND_PAIRING_RANDOM: { 2136 uint8_t buffer[17]; 2137 buffer[0] = SM_CODE_PAIRING_RANDOM; 2138 reverse_128(setup->sm_local_random, &buffer[1]); 2139 if (connection->sm_role){ 2140 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2141 } else { 2142 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2143 } 2144 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2145 sm_timeout_reset(connection); 2146 break; 2147 } 2148 2149 case SM_PH2_GET_RANDOM_TK: 2150 case SM_PH2_C1_GET_RANDOM_A: 2151 case SM_PH2_C1_GET_RANDOM_B: 2152 case SM_PH3_GET_RANDOM: 2153 case SM_PH3_GET_DIV: 2154 sm_next_responding_state(connection); 2155 sm_random_start(connection); 2156 return; 2157 2158 case SM_PH2_C1_GET_ENC_B: 2159 case SM_PH2_C1_GET_ENC_D: 2160 // already busy? 2161 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2162 sm_next_responding_state(connection); 2163 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2164 return; 2165 2166 case SM_PH3_LTK_GET_ENC: 2167 case SM_RESPONDER_PH4_LTK_GET_ENC: 2168 // already busy? 2169 if (sm_aes128_state == SM_AES128_IDLE) { 2170 sm_key_t d_prime; 2171 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2172 sm_next_responding_state(connection); 2173 sm_aes128_start(sm_persistent_er, d_prime, connection); 2174 return; 2175 } 2176 break; 2177 2178 case SM_PH3_CSRK_GET_ENC: 2179 // already busy? 2180 if (sm_aes128_state == SM_AES128_IDLE) { 2181 sm_key_t d_prime; 2182 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2183 sm_next_responding_state(connection); 2184 sm_aes128_start(sm_persistent_er, d_prime, connection); 2185 return; 2186 } 2187 break; 2188 2189 case SM_PH2_C1_GET_ENC_C: 2190 // already busy? 2191 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2192 // calculate m_confirm using aes128 engine - step 1 2193 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); 2194 sm_next_responding_state(connection); 2195 sm_aes128_start(setup->sm_tk, plaintext, connection); 2196 break; 2197 case SM_PH2_C1_GET_ENC_A: 2198 // already busy? 2199 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2200 // calculate confirm using aes128 engine - step 1 2201 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); 2202 sm_next_responding_state(connection); 2203 sm_aes128_start(setup->sm_tk, plaintext, connection); 2204 break; 2205 case SM_PH2_CALC_STK: 2206 // already busy? 2207 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2208 // calculate STK 2209 if (connection->sm_role){ 2210 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2211 } else { 2212 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2213 } 2214 sm_next_responding_state(connection); 2215 sm_aes128_start(setup->sm_tk, plaintext, connection); 2216 break; 2217 case SM_PH3_Y_GET_ENC: 2218 // already busy? 2219 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2220 // PH3B2 - calculate Y from - enc 2221 // Y = dm(DHK, Rand) 2222 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2223 sm_next_responding_state(connection); 2224 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2225 return; 2226 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2227 uint8_t buffer[17]; 2228 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2229 reverse_128(setup->sm_local_confirm, &buffer[1]); 2230 if (connection->sm_role){ 2231 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2232 } else { 2233 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2234 } 2235 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2236 sm_timeout_reset(connection); 2237 return; 2238 } 2239 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2240 sm_key_t stk_flipped; 2241 reverse_128(setup->sm_ltk, stk_flipped); 2242 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2243 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2244 return; 2245 } 2246 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2247 sm_key_t stk_flipped; 2248 reverse_128(setup->sm_ltk, stk_flipped); 2249 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2250 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2251 return; 2252 } 2253 case SM_RESPONDER_PH4_SEND_LTK: { 2254 sm_key_t ltk_flipped; 2255 reverse_128(setup->sm_ltk, ltk_flipped); 2256 connection->sm_engine_state = SM_RESPONDER_IDLE; 2257 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2258 return; 2259 } 2260 case SM_RESPONDER_PH4_Y_GET_ENC: 2261 // already busy? 2262 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2263 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2264 // Y = dm(DHK, Rand) 2265 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2266 sm_next_responding_state(connection); 2267 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2268 return; 2269 2270 case SM_PH3_DISTRIBUTE_KEYS: 2271 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2272 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2273 uint8_t buffer[17]; 2274 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2275 reverse_128(setup->sm_ltk, &buffer[1]); 2276 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2277 sm_timeout_reset(connection); 2278 return; 2279 } 2280 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2281 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2282 uint8_t buffer[11]; 2283 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2284 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2285 reverse_64(setup->sm_local_rand, &buffer[3]); 2286 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2287 sm_timeout_reset(connection); 2288 return; 2289 } 2290 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2291 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2292 uint8_t buffer[17]; 2293 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2294 reverse_128(sm_persistent_irk, &buffer[1]); 2295 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2296 sm_timeout_reset(connection); 2297 return; 2298 } 2299 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2300 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2301 bd_addr_t local_address; 2302 uint8_t buffer[8]; 2303 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2304 gap_advertisements_get_address(&buffer[1], local_address); 2305 reverse_bd_addr(local_address, &buffer[2]); 2306 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2307 sm_timeout_reset(connection); 2308 return; 2309 } 2310 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2311 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2312 2313 // hack to reproduce test runs 2314 if (test_use_fixed_local_csrk){ 2315 memset(setup->sm_local_csrk, 0xcc, 16); 2316 } 2317 2318 uint8_t buffer[17]; 2319 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2320 reverse_128(setup->sm_local_csrk, &buffer[1]); 2321 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2322 sm_timeout_reset(connection); 2323 return; 2324 } 2325 2326 // keys are sent 2327 if (connection->sm_role){ 2328 // slave -> receive master keys if any 2329 if (sm_key_distribution_all_received(connection)){ 2330 sm_key_distribution_handle_all_received(connection); 2331 connection->sm_engine_state = SM_RESPONDER_IDLE; 2332 sm_done_for_handle(connection->sm_handle); 2333 } else { 2334 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2335 } 2336 } else { 2337 // master -> all done 2338 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2339 sm_done_for_handle(connection->sm_handle); 2340 } 2341 break; 2342 2343 default: 2344 break; 2345 } 2346 2347 // check again if active connection was released 2348 if (sm_active_connection) break; 2349 } 2350 } 2351 2352 // note: aes engine is ready as we just got the aes result 2353 static void sm_handle_encryption_result(uint8_t * data){ 2354 2355 sm_aes128_state = SM_AES128_IDLE; 2356 2357 if (sm_address_resolution_ah_calculation_active){ 2358 sm_address_resolution_ah_calculation_active = 0; 2359 // compare calulated address against connecting device 2360 uint8_t hash[3]; 2361 reverse_24(data, hash); 2362 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2363 log_info("LE Device Lookup: matched resolvable private address"); 2364 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2365 return; 2366 } 2367 // no match, try next 2368 sm_address_resolution_test++; 2369 return; 2370 } 2371 2372 switch (dkg_state){ 2373 case DKG_W4_IRK: 2374 reverse_128(data, sm_persistent_irk); 2375 log_info_key("irk", sm_persistent_irk); 2376 dkg_next_state(); 2377 return; 2378 case DKG_W4_DHK: 2379 reverse_128(data, sm_persistent_dhk); 2380 log_info_key("dhk", sm_persistent_dhk); 2381 dkg_next_state(); 2382 // SM Init Finished 2383 return; 2384 default: 2385 break; 2386 } 2387 2388 switch (rau_state){ 2389 case RAU_W4_ENC: 2390 reverse_24(data, &sm_random_address[3]); 2391 rau_next_state(); 2392 return; 2393 default: 2394 break; 2395 } 2396 2397 switch (sm_cmac_state){ 2398 case CMAC_W4_SUBKEYS: 2399 case CMAC_W4_MI: 2400 case CMAC_W4_MLAST: 2401 { 2402 sm_key_t t; 2403 reverse_128(data, t); 2404 sm_cmac_handle_encryption_result(t); 2405 } 2406 return; 2407 default: 2408 break; 2409 } 2410 2411 // retrieve sm_connection provided to sm_aes128_start_encryption 2412 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2413 if (!connection) return; 2414 switch (connection->sm_engine_state){ 2415 case SM_PH2_C1_W4_ENC_A: 2416 case SM_PH2_C1_W4_ENC_C: 2417 { 2418 sm_key_t t2; 2419 reverse_128(data, t2); 2420 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2421 } 2422 sm_next_responding_state(connection); 2423 return; 2424 case SM_PH2_C1_W4_ENC_B: 2425 reverse_128(data, setup->sm_local_confirm); 2426 log_info_key("c1!", setup->sm_local_confirm); 2427 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2428 return; 2429 case SM_PH2_C1_W4_ENC_D: 2430 { 2431 sm_key_t peer_confirm_test; 2432 reverse_128(data, peer_confirm_test); 2433 log_info_key("c1!", peer_confirm_test); 2434 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2435 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2436 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2437 return; 2438 } 2439 if (connection->sm_role){ 2440 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2441 } else { 2442 connection->sm_engine_state = SM_PH2_CALC_STK; 2443 } 2444 } 2445 return; 2446 case SM_PH2_W4_STK: 2447 reverse_128(data, setup->sm_ltk); 2448 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2449 log_info_key("stk", setup->sm_ltk); 2450 if (connection->sm_role){ 2451 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2452 } else { 2453 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2454 } 2455 return; 2456 case SM_PH3_Y_W4_ENC:{ 2457 sm_key_t y128; 2458 reverse_128(data, y128); 2459 setup->sm_local_y = big_endian_read_16(y128, 14); 2460 log_info_hex16("y", setup->sm_local_y); 2461 // PH3B3 - calculate EDIV 2462 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2463 log_info_hex16("ediv", setup->sm_local_ediv); 2464 // PH3B4 - calculate LTK - enc 2465 // LTK = d1(ER, DIV, 0)) 2466 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2467 return; 2468 } 2469 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2470 sm_key_t y128; 2471 reverse_128(data, y128); 2472 setup->sm_local_y = big_endian_read_16(y128, 14); 2473 log_info_hex16("y", setup->sm_local_y); 2474 2475 // PH3B3 - calculate DIV 2476 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2477 log_info_hex16("ediv", setup->sm_local_ediv); 2478 // PH3B4 - calculate LTK - enc 2479 // LTK = d1(ER, DIV, 0)) 2480 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2481 return; 2482 } 2483 case SM_PH3_LTK_W4_ENC: 2484 reverse_128(data, setup->sm_ltk); 2485 log_info_key("ltk", setup->sm_ltk); 2486 // calc CSRK next 2487 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2488 return; 2489 case SM_PH3_CSRK_W4_ENC: 2490 reverse_128(data, setup->sm_local_csrk); 2491 log_info_key("csrk", setup->sm_local_csrk); 2492 if (setup->sm_key_distribution_send_set){ 2493 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2494 } else { 2495 // no keys to send, just continue 2496 if (connection->sm_role){ 2497 // slave -> receive master keys 2498 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2499 } else { 2500 // master -> all done 2501 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2502 sm_done_for_handle(connection->sm_handle); 2503 } 2504 } 2505 return; 2506 case SM_RESPONDER_PH4_LTK_W4_ENC: 2507 reverse_128(data, setup->sm_ltk); 2508 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2509 log_info_key("ltk", setup->sm_ltk); 2510 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2511 return; 2512 default: 2513 break; 2514 } 2515 } 2516 2517 #ifdef USE_MBEDTLS_FOR_ECDH 2518 2519 static void sm_log_ec_keypair(void){ 2520 // print keypair 2521 char buffer[100]; 2522 size_t len; 2523 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 2524 log_info("d: %s", buffer); 2525 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 2526 log_info("X: %s", buffer); 2527 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 2528 log_info("Y: %s", buffer); 2529 } 2530 2531 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2532 int offset = setup->sm_passkey_bit; 2533 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2534 while (size) { 2535 if (offset < 32){ 2536 *buffer++ = setup->sm_peer_qx[offset++]; 2537 } else { 2538 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2539 } 2540 size--; 2541 } 2542 setup->sm_passkey_bit = offset; 2543 return 0; 2544 } 2545 #endif 2546 2547 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2548 static void sm_handle_random_result(uint8_t * data){ 2549 2550 #ifdef USE_MBEDTLS_FOR_ECDH 2551 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2552 int num_bytes = setup->sm_passkey_bit; 2553 if (num_bytes < 32){ 2554 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2555 } else { 2556 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2557 } 2558 num_bytes += 8; 2559 setup->sm_passkey_bit = num_bytes; 2560 2561 if (num_bytes >= 64){ 2562 // generate EC key 2563 setup->sm_passkey_bit = 0; 2564 mbedtls_ecp_gen_key(MBEDTLS_ECP_DP_SECP256R1, &le_keypair, &sm_generate_f_rng, NULL); 2565 sm_log_ec_keypair(); 2566 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2567 } 2568 } 2569 #endif 2570 2571 switch (rau_state){ 2572 case RAU_W4_RANDOM: 2573 // non-resolvable vs. resolvable 2574 switch (gap_random_adress_type){ 2575 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2576 // resolvable: use random as prand and calc address hash 2577 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2578 memcpy(sm_random_address, data, 3); 2579 sm_random_address[0] &= 0x3f; 2580 sm_random_address[0] |= 0x40; 2581 rau_state = RAU_GET_ENC; 2582 break; 2583 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2584 default: 2585 // "The two most significant bits of the address shall be equal to ‘0’"" 2586 memcpy(sm_random_address, data, 6); 2587 sm_random_address[0] &= 0x3f; 2588 rau_state = RAU_SET_ADDRESS; 2589 break; 2590 } 2591 return; 2592 default: 2593 break; 2594 } 2595 2596 // retrieve sm_connection provided to sm_random_start 2597 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2598 if (!connection) return; 2599 switch (connection->sm_engine_state){ 2600 case SM_PH2_W4_RANDOM_TK: 2601 { 2602 // map random to 0-999999 without speding much cycles on a modulus operation 2603 uint32_t tk = little_endian_read_32(data,0); 2604 tk = tk & 0xfffff; // 1048575 2605 if (tk >= 999999){ 2606 tk = tk - 999999; 2607 } 2608 sm_reset_tk(); 2609 big_endian_store_32(setup->sm_tk, 12, tk); 2610 if (connection->sm_role){ 2611 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2612 } else { 2613 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2614 sm_trigger_user_response(connection); 2615 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2616 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2617 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2618 } 2619 } 2620 return; 2621 } 2622 case SM_PH2_C1_W4_RANDOM_A: 2623 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2624 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2625 return; 2626 case SM_PH2_C1_W4_RANDOM_B: 2627 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2628 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2629 return; 2630 case SM_PH3_W4_RANDOM: 2631 reverse_64(data, setup->sm_local_rand); 2632 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2633 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2634 // no db for authenticated flag hack: store flag in bit 4 of LSB 2635 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2636 connection->sm_engine_state = SM_PH3_GET_DIV; 2637 return; 2638 case SM_PH3_W4_DIV: 2639 // use 16 bit from random value as div 2640 setup->sm_local_div = big_endian_read_16(data, 0); 2641 log_info_hex16("div", setup->sm_local_div); 2642 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2643 return; 2644 default: 2645 break; 2646 } 2647 } 2648 2649 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2650 2651 sm_connection_t * sm_conn; 2652 hci_con_handle_t con_handle; 2653 2654 switch (packet_type) { 2655 2656 case HCI_EVENT_PACKET: 2657 switch (hci_event_packet_get_type(packet)) { 2658 2659 case BTSTACK_EVENT_STATE: 2660 // bt stack activated, get started 2661 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2662 log_info("HCI Working!"); 2663 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2664 rau_state = RAU_IDLE; 2665 #ifdef USE_MBEDTLS_FOR_ECDH 2666 if (!test_use_fixed_ec_keypair){ 2667 setup->sm_passkey_bit = 0; 2668 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2669 } 2670 #endif 2671 sm_run(); 2672 } 2673 break; 2674 2675 case HCI_EVENT_LE_META: 2676 switch (packet[2]) { 2677 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2678 2679 log_info("sm: connected"); 2680 2681 if (packet[3]) return; // connection failed 2682 2683 con_handle = little_endian_read_16(packet, 4); 2684 sm_conn = sm_get_connection_for_handle(con_handle); 2685 if (!sm_conn) break; 2686 2687 sm_conn->sm_handle = con_handle; 2688 sm_conn->sm_role = packet[6]; 2689 sm_conn->sm_peer_addr_type = packet[7]; 2690 reverse_bd_addr(&packet[8], 2691 sm_conn->sm_peer_address); 2692 2693 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2694 2695 // reset security properties 2696 sm_conn->sm_connection_encrypted = 0; 2697 sm_conn->sm_connection_authenticated = 0; 2698 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2699 sm_conn->sm_le_db_index = -1; 2700 2701 // prepare CSRK lookup (does not involve setup) 2702 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2703 2704 // just connected -> everything else happens in sm_run() 2705 if (sm_conn->sm_role){ 2706 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2707 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2708 if (sm_slave_request_security) { 2709 // request security if requested by app 2710 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2711 } else { 2712 // otherwise, wait for pairing request 2713 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2714 } 2715 } 2716 break; 2717 } else { 2718 // master 2719 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2720 } 2721 break; 2722 2723 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2724 con_handle = little_endian_read_16(packet, 3); 2725 sm_conn = sm_get_connection_for_handle(con_handle); 2726 if (!sm_conn) break; 2727 2728 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2729 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2730 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2731 break; 2732 } 2733 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2734 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2735 break; 2736 } 2737 2738 // assume that we don't have a LTK for ediv == 0 and random == null 2739 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2740 log_info("LTK Request: ediv & random are empty"); 2741 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2742 break; 2743 } 2744 2745 // store rand and ediv 2746 reverse_64(&packet[5], sm_conn->sm_local_rand); 2747 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2748 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2749 break; 2750 2751 default: 2752 break; 2753 } 2754 break; 2755 2756 case HCI_EVENT_ENCRYPTION_CHANGE: 2757 con_handle = little_endian_read_16(packet, 3); 2758 sm_conn = sm_get_connection_for_handle(con_handle); 2759 if (!sm_conn) break; 2760 2761 sm_conn->sm_connection_encrypted = packet[5]; 2762 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2763 sm_conn->sm_actual_encryption_key_size); 2764 log_info("event handler, state %u", sm_conn->sm_engine_state); 2765 if (!sm_conn->sm_connection_encrypted) break; 2766 // continue if part of initial pairing 2767 switch (sm_conn->sm_engine_state){ 2768 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2769 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2770 sm_done_for_handle(sm_conn->sm_handle); 2771 break; 2772 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2773 if (sm_conn->sm_role){ 2774 // slave 2775 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2776 } else { 2777 // master 2778 if (sm_key_distribution_all_received(sm_conn)){ 2779 // skip receiving keys as there are none 2780 sm_key_distribution_handle_all_received(sm_conn); 2781 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2782 } else { 2783 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2784 } 2785 } 2786 break; 2787 default: 2788 break; 2789 } 2790 break; 2791 2792 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2793 con_handle = little_endian_read_16(packet, 3); 2794 sm_conn = sm_get_connection_for_handle(con_handle); 2795 if (!sm_conn) break; 2796 2797 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2798 log_info("event handler, state %u", sm_conn->sm_engine_state); 2799 // continue if part of initial pairing 2800 switch (sm_conn->sm_engine_state){ 2801 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2802 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2803 sm_done_for_handle(sm_conn->sm_handle); 2804 break; 2805 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2806 if (sm_conn->sm_role){ 2807 // slave 2808 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2809 } else { 2810 // master 2811 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2812 } 2813 break; 2814 default: 2815 break; 2816 } 2817 break; 2818 2819 2820 case HCI_EVENT_DISCONNECTION_COMPLETE: 2821 con_handle = little_endian_read_16(packet, 3); 2822 sm_done_for_handle(con_handle); 2823 sm_conn = sm_get_connection_for_handle(con_handle); 2824 if (!sm_conn) break; 2825 2826 // delete stored bonding on disconnect with authentication failure in ph0 2827 if (sm_conn->sm_role == 0 2828 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2829 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2830 le_device_db_remove(sm_conn->sm_le_db_index); 2831 } 2832 2833 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2834 sm_conn->sm_handle = 0; 2835 break; 2836 2837 case HCI_EVENT_COMMAND_COMPLETE: 2838 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2839 sm_handle_encryption_result(&packet[6]); 2840 break; 2841 } 2842 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2843 sm_handle_random_result(&packet[6]); 2844 break; 2845 } 2846 break; 2847 default: 2848 break; 2849 } 2850 break; 2851 default: 2852 break; 2853 } 2854 2855 sm_run(); 2856 } 2857 2858 static inline int sm_calc_actual_encryption_key_size(int other){ 2859 if (other < sm_min_encryption_key_size) return 0; 2860 if (other < sm_max_encryption_key_size) return other; 2861 return sm_max_encryption_key_size; 2862 } 2863 2864 static int sm_passkey_used(stk_generation_method_t method){ 2865 switch (method){ 2866 case PK_RESP_INPUT: 2867 case PK_INIT_INPUT: 2868 case OK_BOTH_INPUT: 2869 return 1; 2870 default: 2871 return 0; 2872 } 2873 } 2874 2875 /** 2876 * @return ok 2877 */ 2878 static int sm_validate_stk_generation_method(void){ 2879 // check if STK generation method is acceptable by client 2880 switch (setup->sm_stk_generation_method){ 2881 case JUST_WORKS: 2882 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2883 case PK_RESP_INPUT: 2884 case PK_INIT_INPUT: 2885 case OK_BOTH_INPUT: 2886 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2887 case OOB: 2888 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2889 case NK_BOTH_INPUT: 2890 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2891 return 1; 2892 default: 2893 return 0; 2894 } 2895 } 2896 2897 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2898 2899 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2900 sm_run(); 2901 } 2902 2903 if (packet_type != SM_DATA_PACKET) return; 2904 2905 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2906 if (!sm_conn) return; 2907 2908 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2909 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2910 return; 2911 } 2912 2913 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2914 2915 int err; 2916 2917 switch (sm_conn->sm_engine_state){ 2918 2919 // a sm timeout requries a new physical connection 2920 case SM_GENERAL_TIMEOUT: 2921 return; 2922 2923 // Initiator 2924 case SM_INITIATOR_CONNECTED: 2925 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2926 sm_pdu_received_in_wrong_state(sm_conn); 2927 break; 2928 } 2929 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2930 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2931 break; 2932 } 2933 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2934 uint16_t ediv; 2935 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2936 if (ediv){ 2937 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2938 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2939 } else { 2940 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2941 } 2942 break; 2943 } 2944 // otherwise, store security request 2945 sm_conn->sm_security_request_received = 1; 2946 break; 2947 2948 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2949 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2950 sm_pdu_received_in_wrong_state(sm_conn); 2951 break; 2952 } 2953 // store pairing request 2954 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2955 err = sm_stk_generation_init(sm_conn); 2956 if (err){ 2957 setup->sm_pairing_failed_reason = err; 2958 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2959 break; 2960 } 2961 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2962 if (setup->sm_use_secure_connections){ 2963 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2964 if (setup->sm_stk_generation_method == JUST_WORKS){ 2965 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2966 sm_trigger_user_response(sm_conn); 2967 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2968 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2969 } 2970 } else { 2971 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2972 } 2973 break; 2974 } 2975 #endif 2976 // generate random number first, if we need to show passkey 2977 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2978 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2979 break; 2980 } 2981 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2982 sm_trigger_user_response(sm_conn); 2983 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2984 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2985 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2986 } 2987 break; 2988 2989 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2990 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2991 sm_pdu_received_in_wrong_state(sm_conn); 2992 break; 2993 } 2994 2995 // store s_confirm 2996 reverse_128(&packet[1], setup->sm_peer_confirm); 2997 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2998 break; 2999 3000 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3001 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3002 sm_pdu_received_in_wrong_state(sm_conn); 3003 break;; 3004 } 3005 3006 // received random value 3007 reverse_128(&packet[1], setup->sm_peer_random); 3008 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3009 break; 3010 3011 // Responder 3012 case SM_RESPONDER_IDLE: 3013 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3014 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3015 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3016 sm_pdu_received_in_wrong_state(sm_conn); 3017 break;; 3018 } 3019 3020 // store pairing request 3021 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3022 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3023 break; 3024 3025 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3026 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3027 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3028 sm_pdu_received_in_wrong_state(sm_conn); 3029 break; 3030 } 3031 3032 // store public key for DH Key calculation 3033 reverse_256(&packet[01], setup->sm_peer_qx); 3034 reverse_256(&packet[33], setup->sm_peer_qy); 3035 3036 #ifdef USE_MBEDTLS_FOR_ECDH 3037 // validate public key 3038 mbedtls_ecp_group grp; 3039 mbedtls_ecp_group_init( &grp ); 3040 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 3041 3042 mbedtls_ecp_point Q; 3043 mbedtls_ecp_point_init( &Q ); 3044 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3045 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3046 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3047 err = mbedtls_ecp_check_pubkey(&grp, &Q); 3048 if (err){ 3049 log_error("sm: peer public key invalid %x", err); 3050 // uses "unspecified reason", there is no "public key invalid" error code 3051 sm_pdu_received_in_wrong_state(sm_conn); 3052 break; 3053 } 3054 #endif 3055 if (sm_conn->sm_role){ 3056 // responder 3057 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3058 } else { 3059 // initiator 3060 // stk generation method 3061 // passkey entry: notify app to show passkey or to request passkey 3062 switch (setup->sm_stk_generation_method){ 3063 case JUST_WORKS: 3064 case NK_BOTH_INPUT: 3065 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3066 break; 3067 case PK_INIT_INPUT: 3068 case PK_RESP_INPUT: 3069 case OK_BOTH_INPUT: 3070 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3071 break; 3072 case OOB: 3073 // TODO: implement SC OOB 3074 break; 3075 } 3076 } 3077 break; 3078 3079 case SM_SC_W4_CONFIRMATION: 3080 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3081 sm_pdu_received_in_wrong_state(sm_conn); 3082 break; 3083 } 3084 // received confirm value 3085 reverse_128(&packet[1], setup->sm_peer_confirm); 3086 3087 if (sm_conn->sm_role){ 3088 // responder 3089 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3090 } else { 3091 // initiator 3092 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3093 } 3094 break; 3095 3096 case SM_SC_W4_PAIRING_RANDOM: 3097 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3098 sm_pdu_received_in_wrong_state(sm_conn); 3099 break; 3100 } 3101 3102 // received random value 3103 reverse_128(&packet[1], setup->sm_peer_nonce); 3104 3105 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3106 // only check for JUST WORK/NC in initiator role AND passkey entry 3107 int passkey_entry = sm_passkey_used(setup->sm_stk_generation_method); 3108 if (sm_conn->sm_role || passkey_entry) { 3109 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3110 } 3111 3112 sm_sc_state_after_receiving_random(sm_conn); 3113 break; 3114 3115 case SM_SC_W2_CALCULATE_G2: 3116 case SM_SC_W4_CALCULATE_G2: 3117 case SM_SC_W2_CALCULATE_F5_SALT: 3118 case SM_SC_W4_CALCULATE_F5_SALT: 3119 case SM_SC_W2_CALCULATE_F5_MACKEY: 3120 case SM_SC_W4_CALCULATE_F5_MACKEY: 3121 case SM_SC_W2_CALCULATE_F5_LTK: 3122 case SM_SC_W4_CALCULATE_F5_LTK: 3123 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3124 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3125 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3126 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3127 sm_pdu_received_in_wrong_state(sm_conn); 3128 break; 3129 } 3130 // store DHKey Check 3131 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3132 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3133 3134 // have we been only waiting for dhkey check command? 3135 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3136 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3137 } 3138 break; 3139 #endif 3140 3141 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3142 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3143 sm_pdu_received_in_wrong_state(sm_conn); 3144 break; 3145 } 3146 3147 // received confirm value 3148 reverse_128(&packet[1], setup->sm_peer_confirm); 3149 3150 // notify client to hide shown passkey 3151 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3152 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3153 } 3154 3155 // handle user cancel pairing? 3156 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3157 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3158 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3159 break; 3160 } 3161 3162 // wait for user action? 3163 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3164 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3165 break; 3166 } 3167 3168 // calculate and send local_confirm 3169 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3170 break; 3171 3172 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3173 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3174 sm_pdu_received_in_wrong_state(sm_conn); 3175 break;; 3176 } 3177 3178 // received random value 3179 reverse_128(&packet[1], setup->sm_peer_random); 3180 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3181 break; 3182 3183 case SM_PH3_RECEIVE_KEYS: 3184 switch(packet[0]){ 3185 case SM_CODE_ENCRYPTION_INFORMATION: 3186 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3187 reverse_128(&packet[1], setup->sm_peer_ltk); 3188 break; 3189 3190 case SM_CODE_MASTER_IDENTIFICATION: 3191 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3192 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3193 reverse_64(&packet[3], setup->sm_peer_rand); 3194 break; 3195 3196 case SM_CODE_IDENTITY_INFORMATION: 3197 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3198 reverse_128(&packet[1], setup->sm_peer_irk); 3199 break; 3200 3201 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3202 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3203 setup->sm_peer_addr_type = packet[1]; 3204 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3205 break; 3206 3207 case SM_CODE_SIGNING_INFORMATION: 3208 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3209 reverse_128(&packet[1], setup->sm_peer_csrk); 3210 break; 3211 default: 3212 // Unexpected PDU 3213 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3214 break; 3215 } 3216 // done with key distribution? 3217 if (sm_key_distribution_all_received(sm_conn)){ 3218 3219 sm_key_distribution_handle_all_received(sm_conn); 3220 3221 if (sm_conn->sm_role){ 3222 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3223 sm_done_for_handle(sm_conn->sm_handle); 3224 } else { 3225 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3226 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3227 if (setup->sm_use_secure_connections){ 3228 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3229 } 3230 #endif 3231 } 3232 } 3233 break; 3234 default: 3235 // Unexpected PDU 3236 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3237 break; 3238 } 3239 3240 // try to send preparared packet 3241 sm_run(); 3242 } 3243 3244 // Security Manager Client API 3245 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3246 sm_get_oob_data = get_oob_data_callback; 3247 } 3248 3249 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3250 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3251 } 3252 3253 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3254 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3255 } 3256 3257 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3258 sm_min_encryption_key_size = min_size; 3259 sm_max_encryption_key_size = max_size; 3260 } 3261 3262 void sm_set_authentication_requirements(uint8_t auth_req){ 3263 sm_auth_req = auth_req; 3264 } 3265 3266 void sm_set_io_capabilities(io_capability_t io_capability){ 3267 sm_io_capabilities = io_capability; 3268 } 3269 3270 void sm_set_request_security(int enable){ 3271 sm_slave_request_security = enable; 3272 } 3273 3274 void sm_set_er(sm_key_t er){ 3275 memcpy(sm_persistent_er, er, 16); 3276 } 3277 3278 void sm_set_ir(sm_key_t ir){ 3279 memcpy(sm_persistent_ir, ir, 16); 3280 } 3281 3282 // Testing support only 3283 void sm_test_set_irk(sm_key_t irk){ 3284 memcpy(sm_persistent_irk, irk, 16); 3285 sm_persistent_irk_ready = 1; 3286 } 3287 3288 void sm_test_use_fixed_local_csrk(void){ 3289 test_use_fixed_local_csrk = 1; 3290 } 3291 3292 void sm_init(void){ 3293 // set some (BTstack default) ER and IR 3294 int i; 3295 sm_key_t er; 3296 sm_key_t ir; 3297 for (i=0;i<16;i++){ 3298 er[i] = 0x30 + i; 3299 ir[i] = 0x90 + i; 3300 } 3301 sm_set_er(er); 3302 sm_set_ir(ir); 3303 // defaults 3304 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3305 | SM_STK_GENERATION_METHOD_OOB 3306 | SM_STK_GENERATION_METHOD_PASSKEY 3307 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3308 3309 sm_max_encryption_key_size = 16; 3310 sm_min_encryption_key_size = 7; 3311 3312 sm_cmac_state = CMAC_IDLE; 3313 dkg_state = DKG_W4_WORKING; 3314 rau_state = RAU_W4_WORKING; 3315 sm_aes128_state = SM_AES128_IDLE; 3316 sm_address_resolution_test = -1; // no private address to resolve yet 3317 sm_address_resolution_ah_calculation_active = 0; 3318 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3319 sm_address_resolution_general_queue = NULL; 3320 3321 gap_random_adress_update_period = 15 * 60 * 1000L; 3322 3323 sm_active_connection = 0; 3324 3325 test_use_fixed_local_csrk = 0; 3326 3327 // register for HCI Events from HCI 3328 hci_event_callback_registration.callback = &sm_event_packet_handler; 3329 hci_add_event_handler(&hci_event_callback_registration); 3330 3331 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3332 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3333 3334 #ifdef USE_MBEDTLS_FOR_ECDH 3335 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3336 #endif 3337 } 3338 3339 void sm_test_use_fixed_ec_keypair(void){ 3340 test_use_fixed_ec_keypair = 1; 3341 #ifdef USE_MBEDTLS_FOR_ECDH 3342 // use test keypair from spec 3343 mbedtls_ecp_keypair_init(&le_keypair); 3344 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3345 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3346 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3347 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3348 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3349 #endif 3350 } 3351 3352 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3353 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3354 if (!hci_con) return NULL; 3355 return &hci_con->sm_connection; 3356 } 3357 3358 // @returns 0 if not encrypted, 7-16 otherwise 3359 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3360 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3361 if (!sm_conn) return 0; // wrong connection 3362 if (!sm_conn->sm_connection_encrypted) return 0; 3363 return sm_conn->sm_actual_encryption_key_size; 3364 } 3365 3366 int sm_authenticated(hci_con_handle_t con_handle){ 3367 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3368 if (!sm_conn) return 0; // wrong connection 3369 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3370 return sm_conn->sm_connection_authenticated; 3371 } 3372 3373 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3374 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3375 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3376 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3377 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3378 return sm_conn->sm_connection_authorization_state; 3379 } 3380 3381 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3382 switch (sm_conn->sm_engine_state){ 3383 case SM_GENERAL_IDLE: 3384 case SM_RESPONDER_IDLE: 3385 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3386 sm_run(); 3387 break; 3388 default: 3389 break; 3390 } 3391 } 3392 3393 /** 3394 * @brief Trigger Security Request 3395 */ 3396 void sm_send_security_request(hci_con_handle_t con_handle){ 3397 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3398 if (!sm_conn) return; 3399 sm_send_security_request_for_connection(sm_conn); 3400 } 3401 3402 // request pairing 3403 void sm_request_pairing(hci_con_handle_t con_handle){ 3404 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3405 if (!sm_conn) return; // wrong connection 3406 3407 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3408 if (sm_conn->sm_role){ 3409 sm_send_security_request_for_connection(sm_conn); 3410 } else { 3411 // used as a trigger to start central/master/initiator security procedures 3412 uint16_t ediv; 3413 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3414 switch (sm_conn->sm_irk_lookup_state){ 3415 case IRK_LOOKUP_FAILED: 3416 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3417 break; 3418 case IRK_LOOKUP_SUCCEEDED: 3419 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3420 if (ediv){ 3421 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3422 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3423 } else { 3424 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3425 } 3426 break; 3427 default: 3428 sm_conn->sm_bonding_requested = 1; 3429 break; 3430 } 3431 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3432 sm_conn->sm_bonding_requested = 1; 3433 } 3434 } 3435 sm_run(); 3436 } 3437 3438 // called by client app on authorization request 3439 void sm_authorization_decline(hci_con_handle_t con_handle){ 3440 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3441 if (!sm_conn) return; // wrong connection 3442 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3443 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3444 } 3445 3446 void sm_authorization_grant(hci_con_handle_t con_handle){ 3447 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3448 if (!sm_conn) return; // wrong connection 3449 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3450 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3451 } 3452 3453 // GAP Bonding API 3454 3455 void sm_bonding_decline(hci_con_handle_t con_handle){ 3456 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3457 if (!sm_conn) return; // wrong connection 3458 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3459 3460 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3461 switch (setup->sm_stk_generation_method){ 3462 case PK_RESP_INPUT: 3463 case PK_INIT_INPUT: 3464 case OK_BOTH_INPUT: 3465 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3466 break; 3467 case NK_BOTH_INPUT: 3468 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3469 break; 3470 case JUST_WORKS: 3471 case OOB: 3472 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3473 break; 3474 } 3475 } 3476 sm_run(); 3477 } 3478 3479 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3480 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3481 if (!sm_conn) return; // wrong connection 3482 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3483 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3484 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3485 3486 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3487 if (setup->sm_use_secure_connections){ 3488 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3489 } 3490 #endif 3491 } 3492 3493 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3494 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3495 sm_sc_prepare_dhkey_check(sm_conn); 3496 } 3497 #endif 3498 3499 sm_run(); 3500 } 3501 3502 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3503 // for now, it's the same 3504 sm_just_works_confirm(con_handle); 3505 } 3506 3507 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3508 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3509 if (!sm_conn) return; // wrong connection 3510 sm_reset_tk(); 3511 big_endian_store_32(setup->sm_tk, 12, passkey); 3512 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3513 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3514 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3515 } 3516 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3517 // if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3518 // sm_sc_prepare_dhkey_check(sm_conn); 3519 // } 3520 #endif 3521 sm_run(); 3522 } 3523 3524 /** 3525 * @brief Identify device in LE Device DB 3526 * @param handle 3527 * @returns index from le_device_db or -1 if not found/identified 3528 */ 3529 int sm_le_device_index(hci_con_handle_t con_handle ){ 3530 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3531 if (!sm_conn) return -1; 3532 return sm_conn->sm_le_db_index; 3533 } 3534 3535 // GAP LE API 3536 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3537 gap_random_address_update_stop(); 3538 gap_random_adress_type = random_address_type; 3539 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3540 gap_random_address_update_start(); 3541 gap_random_address_trigger(); 3542 } 3543 3544 gap_random_address_type_t gap_random_address_get_mode(void){ 3545 return gap_random_adress_type; 3546 } 3547 3548 void gap_random_address_set_update_period(int period_ms){ 3549 gap_random_adress_update_period = period_ms; 3550 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3551 gap_random_address_update_stop(); 3552 gap_random_address_update_start(); 3553 } 3554 3555 void gap_random_address_set(bd_addr_t addr){ 3556 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3557 memcpy(sm_random_address, addr, 6); 3558 rau_state = RAU_SET_ADDRESS; 3559 sm_run(); 3560 } 3561 3562 /* 3563 * @brief Set Advertisement Paramters 3564 * @param adv_int_min 3565 * @param adv_int_max 3566 * @param adv_type 3567 * @param direct_address_type 3568 * @param direct_address 3569 * @param channel_map 3570 * @param filter_policy 3571 * 3572 * @note own_address_type is used from gap_random_address_set_mode 3573 */ 3574 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3575 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3576 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3577 direct_address_typ, direct_address, channel_map, filter_policy); 3578 } 3579 3580