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 uint8_t z = 0; 1575 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1576 // some form of passkey 1577 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1578 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1579 setup->sm_passkey_bit++; 1580 } 1581 #ifdef USE_MBEDTLS_FOR_ECDH 1582 uint8_t local_qx[32]; 1583 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1584 #endif 1585 f4_engine(sm_conn, local_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1586 } 1587 1588 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1589 uint8_t z = 0; 1590 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1591 // some form of passkey 1592 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1593 // sm_passkey_bit was increased before sending confirm value 1594 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1595 } 1596 #ifdef USE_MBEDTLS_FOR_ECDH 1597 uint8_t local_qx[32]; 1598 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1599 #endif 1600 f4_engine(sm_conn, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 1601 } 1602 1603 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1604 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1605 } 1606 1607 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1608 // calculate DHKCheck 1609 sm_key56_t bd_addr_master, bd_addr_slave; 1610 bd_addr_master[0] = setup->sm_m_addr_type; 1611 bd_addr_slave[0] = setup->sm_s_addr_type; 1612 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1613 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1614 uint8_t iocap_a[3]; 1615 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1616 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1617 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1618 uint8_t iocap_b[3]; 1619 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1620 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1621 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1622 if (sm_conn->sm_role){ 1623 // responder 1624 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); 1625 } else { 1626 // initiator 1627 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); 1628 } 1629 } 1630 1631 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1632 // validate E = f6() 1633 sm_key56_t bd_addr_master, bd_addr_slave; 1634 bd_addr_master[0] = setup->sm_m_addr_type; 1635 bd_addr_slave[0] = setup->sm_s_addr_type; 1636 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1637 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1638 1639 uint8_t iocap_a[3]; 1640 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1641 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1642 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1643 uint8_t iocap_b[3]; 1644 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1645 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1646 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1647 if (sm_conn->sm_role){ 1648 // responder 1649 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); 1650 } else { 1651 // initiator 1652 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); 1653 } 1654 } 1655 #endif 1656 1657 1658 static void sm_run(void){ 1659 1660 btstack_linked_list_iterator_t it; 1661 1662 // assert that we can send at least commands 1663 if (!hci_can_send_command_packet_now()) return; 1664 1665 // 1666 // non-connection related behaviour 1667 // 1668 1669 // distributed key generation 1670 switch (dkg_state){ 1671 case DKG_CALC_IRK: 1672 // already busy? 1673 if (sm_aes128_state == SM_AES128_IDLE) { 1674 // IRK = d1(IR, 1, 0) 1675 sm_key_t d1_prime; 1676 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1677 dkg_next_state(); 1678 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1679 return; 1680 } 1681 break; 1682 case DKG_CALC_DHK: 1683 // already busy? 1684 if (sm_aes128_state == SM_AES128_IDLE) { 1685 // DHK = d1(IR, 3, 0) 1686 sm_key_t d1_prime; 1687 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1688 dkg_next_state(); 1689 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1690 return; 1691 } 1692 break; 1693 default: 1694 break; 1695 } 1696 1697 #ifdef USE_MBEDTLS_FOR_ECDH 1698 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1699 sm_random_start(NULL); 1700 return; 1701 } 1702 #endif 1703 1704 // random address updates 1705 switch (rau_state){ 1706 case RAU_GET_RANDOM: 1707 rau_next_state(); 1708 sm_random_start(NULL); 1709 return; 1710 case RAU_GET_ENC: 1711 // already busy? 1712 if (sm_aes128_state == SM_AES128_IDLE) { 1713 sm_key_t r_prime; 1714 sm_ah_r_prime(sm_random_address, r_prime); 1715 rau_next_state(); 1716 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1717 return; 1718 } 1719 break; 1720 case RAU_SET_ADDRESS: 1721 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1722 rau_state = RAU_IDLE; 1723 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1724 return; 1725 default: 1726 break; 1727 } 1728 1729 // CMAC 1730 switch (sm_cmac_state){ 1731 case CMAC_CALC_SUBKEYS: 1732 case CMAC_CALC_MI: 1733 case CMAC_CALC_MLAST: 1734 // already busy? 1735 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1736 sm_cmac_handle_aes_engine_ready(); 1737 return; 1738 default: 1739 break; 1740 } 1741 1742 // CSRK Lookup 1743 // -- if csrk lookup ready, find connection that require csrk lookup 1744 if (sm_address_resolution_idle()){ 1745 hci_connections_get_iterator(&it); 1746 while(btstack_linked_list_iterator_has_next(&it)){ 1747 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1748 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1749 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1750 // and start lookup 1751 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); 1752 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1753 break; 1754 } 1755 } 1756 } 1757 1758 // -- if csrk lookup ready, resolved addresses for received addresses 1759 if (sm_address_resolution_idle()) { 1760 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1761 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1762 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1763 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1764 btstack_memory_sm_lookup_entry_free(entry); 1765 } 1766 } 1767 1768 // -- Continue with CSRK device lookup by public or resolvable private address 1769 if (!sm_address_resolution_idle()){ 1770 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1771 while (sm_address_resolution_test < le_device_db_count()){ 1772 int addr_type; 1773 bd_addr_t addr; 1774 sm_key_t irk; 1775 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1776 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1777 1778 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1779 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1780 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1781 break; 1782 } 1783 1784 if (sm_address_resolution_addr_type == 0){ 1785 sm_address_resolution_test++; 1786 continue; 1787 } 1788 1789 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1790 1791 log_info("LE Device Lookup: calculate AH"); 1792 log_info_key("IRK", irk); 1793 1794 sm_key_t r_prime; 1795 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1796 sm_address_resolution_ah_calculation_active = 1; 1797 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1798 return; 1799 } 1800 1801 if (sm_address_resolution_test >= le_device_db_count()){ 1802 log_info("LE Device Lookup: not found"); 1803 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1804 } 1805 } 1806 1807 1808 // 1809 // active connection handling 1810 // -- use loop to handle next connection if lock on setup context is released 1811 1812 while (1) { 1813 1814 // Find connections that requires setup context and make active if no other is locked 1815 hci_connections_get_iterator(&it); 1816 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1817 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1818 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1819 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1820 int done = 1; 1821 int err; 1822 int encryption_key_size; 1823 int authenticated; 1824 int authorized; 1825 switch (sm_connection->sm_engine_state) { 1826 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1827 // send packet if possible, 1828 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1829 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1830 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1831 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1832 } else { 1833 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1834 } 1835 // don't lock setup context yet 1836 done = 0; 1837 break; 1838 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1839 sm_init_setup(sm_connection); 1840 // recover pairing request 1841 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1842 err = sm_stk_generation_init(sm_connection); 1843 if (err){ 1844 setup->sm_pairing_failed_reason = err; 1845 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1846 break; 1847 } 1848 sm_timeout_start(sm_connection); 1849 // generate random number first, if we need to show passkey 1850 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1851 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1852 break; 1853 } 1854 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1855 break; 1856 case SM_INITIATOR_PH0_HAS_LTK: 1857 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1858 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1859 &encryption_key_size, &authenticated, &authorized); 1860 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1861 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1862 sm_connection->sm_connection_authenticated = authenticated; 1863 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1864 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1865 break; 1866 case SM_RESPONDER_PH0_RECEIVED_LTK: 1867 // re-establish previously used LTK using Rand and EDIV 1868 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1869 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1870 // re-establish used key encryption size 1871 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1872 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1873 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1874 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1875 log_info("sm: received ltk request with key size %u, authenticated %u", 1876 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1877 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1878 break; 1879 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1880 sm_init_setup(sm_connection); 1881 sm_timeout_start(sm_connection); 1882 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1883 break; 1884 default: 1885 done = 0; 1886 break; 1887 } 1888 if (done){ 1889 sm_active_connection = sm_connection->sm_handle; 1890 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1891 } 1892 } 1893 1894 // 1895 // active connection handling 1896 // 1897 1898 if (sm_active_connection == 0) return; 1899 1900 // assert that we could send a SM PDU - not needed for all of the following 1901 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1902 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1903 return; 1904 } 1905 1906 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1907 if (!connection) return; 1908 1909 sm_key_t plaintext; 1910 int key_distribution_flags; 1911 1912 log_info("sm_run: state %u", connection->sm_engine_state); 1913 1914 // responding state 1915 switch (connection->sm_engine_state){ 1916 1917 // general 1918 case SM_GENERAL_SEND_PAIRING_FAILED: { 1919 uint8_t buffer[2]; 1920 buffer[0] = SM_CODE_PAIRING_FAILED; 1921 buffer[1] = setup->sm_pairing_failed_reason; 1922 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1923 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1924 sm_done_for_handle(connection->sm_handle); 1925 break; 1926 } 1927 1928 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1929 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1930 if (!sm_cmac_ready()) break; 1931 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1932 sm_sc_calculate_local_confirm(connection); 1933 break; 1934 1935 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 1936 if (!sm_cmac_ready()) break; 1937 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 1938 sm_sc_calculate_remote_confirm(connection); 1939 break; 1940 1941 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 1942 if (!sm_cmac_ready()) break; 1943 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 1944 sm_sc_calculate_f6_for_dhkey_check(connection); 1945 break; 1946 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1947 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1948 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 1949 break; 1950 case SM_SC_W2_CALCULATE_F5_SALT: 1951 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 1952 f5_calculate_salt(connection); 1953 break; 1954 case SM_SC_W2_CALCULATE_F5_MACKEY: 1955 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 1956 f5_calculate_mackey(connection); 1957 break; 1958 case SM_SC_W2_CALCULATE_F5_LTK: 1959 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 1960 f5_calculate_ltk(connection); 1961 break; 1962 case SM_SC_W2_CALCULATE_G2: 1963 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 1964 g2_calculate_engine(connection); 1965 break; 1966 1967 #endif 1968 // initiator side 1969 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1970 sm_key_t peer_ltk_flipped; 1971 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1972 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1973 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1974 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1975 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1976 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1977 return; 1978 } 1979 1980 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1981 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1982 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1983 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1984 sm_timeout_reset(connection); 1985 break; 1986 1987 // responder side 1988 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1989 connection->sm_engine_state = SM_RESPONDER_IDLE; 1990 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1991 return; 1992 1993 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1994 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1995 uint8_t buffer[65]; 1996 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1997 // 1998 #ifdef USE_MBEDTLS_FOR_ECDH 1999 uint8_t value[32]; 2000 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2001 reverse_256(value, &buffer[1]); 2002 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 2003 reverse_256(value, &buffer[33]); 2004 #endif 2005 // TODO: use random generator to generate nonce 2006 2007 // generate 128-bit nonce 2008 int i; 2009 for (i=0;i<16;i++){ 2010 setup->sm_local_nonce[i] = rand() & 0xff; 2011 } 2012 2013 // stk generation method 2014 // passkey entry: notify app to show passkey or to request passkey 2015 switch (setup->sm_stk_generation_method){ 2016 case JUST_WORKS: 2017 case NK_BOTH_INPUT: 2018 if (connection->sm_role){ 2019 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2020 } else { 2021 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2022 } 2023 break; 2024 case PK_INIT_INPUT: 2025 case PK_RESP_INPUT: 2026 case OK_BOTH_INPUT: 2027 // hack for testing: assume user entered '000000' 2028 // memset(setup->sm_tk, 0, 16); 2029 memcpy(setup->sm_ra, setup->sm_tk, 16); 2030 memcpy(setup->sm_rb, setup->sm_tk, 16); 2031 setup->sm_passkey_bit = 0; 2032 if (connection->sm_role){ 2033 // responder 2034 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2035 } else { 2036 // initiator 2037 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2038 } 2039 sm_trigger_user_response(connection); 2040 break; 2041 case OOB: 2042 // TODO: implement SC OOB 2043 break; 2044 } 2045 2046 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2047 sm_timeout_reset(connection); 2048 break; 2049 } 2050 case SM_SC_SEND_CONFIRMATION: { 2051 uint8_t buffer[17]; 2052 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2053 reverse_128(setup->sm_local_confirm, &buffer[1]); 2054 if (connection->sm_role){ 2055 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2056 } else { 2057 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2058 } 2059 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2060 sm_timeout_reset(connection); 2061 break; 2062 } 2063 case SM_SC_SEND_PAIRING_RANDOM: { 2064 uint8_t buffer[17]; 2065 buffer[0] = SM_CODE_PAIRING_RANDOM; 2066 reverse_128(setup->sm_local_nonce, &buffer[1]); 2067 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2068 if (connection->sm_role){ 2069 // responder 2070 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2071 } else { 2072 // initiator 2073 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2074 } 2075 } else { 2076 if (connection->sm_role){ 2077 // responder 2078 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2079 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2080 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2081 } 2082 } else { 2083 // initiator 2084 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2085 } 2086 } 2087 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2088 sm_timeout_reset(connection); 2089 break; 2090 } 2091 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2092 uint8_t buffer[17]; 2093 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2094 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2095 2096 if (connection->sm_role){ 2097 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2098 } else { 2099 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2100 } 2101 2102 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2103 sm_timeout_reset(connection); 2104 break; 2105 } 2106 2107 #endif 2108 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2109 // echo initiator for now 2110 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2111 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2112 2113 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2114 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2115 if (setup->sm_use_secure_connections){ 2116 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2117 // skip LTK/EDIV for SC 2118 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2119 } 2120 #endif 2121 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); 2122 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); 2123 2124 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2125 sm_timeout_reset(connection); 2126 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2127 if (setup->sm_stk_generation_method == JUST_WORKS){ 2128 sm_trigger_user_response(connection); 2129 } 2130 return; 2131 2132 case SM_PH2_SEND_PAIRING_RANDOM: { 2133 uint8_t buffer[17]; 2134 buffer[0] = SM_CODE_PAIRING_RANDOM; 2135 reverse_128(setup->sm_local_random, &buffer[1]); 2136 if (connection->sm_role){ 2137 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2138 } else { 2139 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2140 } 2141 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2142 sm_timeout_reset(connection); 2143 break; 2144 } 2145 2146 case SM_PH2_GET_RANDOM_TK: 2147 case SM_PH2_C1_GET_RANDOM_A: 2148 case SM_PH2_C1_GET_RANDOM_B: 2149 case SM_PH3_GET_RANDOM: 2150 case SM_PH3_GET_DIV: 2151 sm_next_responding_state(connection); 2152 sm_random_start(connection); 2153 return; 2154 2155 case SM_PH2_C1_GET_ENC_B: 2156 case SM_PH2_C1_GET_ENC_D: 2157 // already busy? 2158 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2159 sm_next_responding_state(connection); 2160 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2161 return; 2162 2163 case SM_PH3_LTK_GET_ENC: 2164 case SM_RESPONDER_PH4_LTK_GET_ENC: 2165 // already busy? 2166 if (sm_aes128_state == SM_AES128_IDLE) { 2167 sm_key_t d_prime; 2168 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2169 sm_next_responding_state(connection); 2170 sm_aes128_start(sm_persistent_er, d_prime, connection); 2171 return; 2172 } 2173 break; 2174 2175 case SM_PH3_CSRK_GET_ENC: 2176 // already busy? 2177 if (sm_aes128_state == SM_AES128_IDLE) { 2178 sm_key_t d_prime; 2179 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2180 sm_next_responding_state(connection); 2181 sm_aes128_start(sm_persistent_er, d_prime, connection); 2182 return; 2183 } 2184 break; 2185 2186 case SM_PH2_C1_GET_ENC_C: 2187 // already busy? 2188 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2189 // calculate m_confirm using aes128 engine - step 1 2190 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); 2191 sm_next_responding_state(connection); 2192 sm_aes128_start(setup->sm_tk, plaintext, connection); 2193 break; 2194 case SM_PH2_C1_GET_ENC_A: 2195 // already busy? 2196 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2197 // calculate confirm using aes128 engine - step 1 2198 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); 2199 sm_next_responding_state(connection); 2200 sm_aes128_start(setup->sm_tk, plaintext, connection); 2201 break; 2202 case SM_PH2_CALC_STK: 2203 // already busy? 2204 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2205 // calculate STK 2206 if (connection->sm_role){ 2207 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2208 } else { 2209 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2210 } 2211 sm_next_responding_state(connection); 2212 sm_aes128_start(setup->sm_tk, plaintext, connection); 2213 break; 2214 case SM_PH3_Y_GET_ENC: 2215 // already busy? 2216 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2217 // PH3B2 - calculate Y from - enc 2218 // Y = dm(DHK, Rand) 2219 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2220 sm_next_responding_state(connection); 2221 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2222 return; 2223 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2224 uint8_t buffer[17]; 2225 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2226 reverse_128(setup->sm_local_confirm, &buffer[1]); 2227 if (connection->sm_role){ 2228 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2229 } else { 2230 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2231 } 2232 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2233 sm_timeout_reset(connection); 2234 return; 2235 } 2236 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2237 sm_key_t stk_flipped; 2238 reverse_128(setup->sm_ltk, stk_flipped); 2239 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2240 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2241 return; 2242 } 2243 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2244 sm_key_t stk_flipped; 2245 reverse_128(setup->sm_ltk, stk_flipped); 2246 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2247 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2248 return; 2249 } 2250 case SM_RESPONDER_PH4_SEND_LTK: { 2251 sm_key_t ltk_flipped; 2252 reverse_128(setup->sm_ltk, ltk_flipped); 2253 connection->sm_engine_state = SM_RESPONDER_IDLE; 2254 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2255 return; 2256 } 2257 case SM_RESPONDER_PH4_Y_GET_ENC: 2258 // already busy? 2259 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2260 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2261 // Y = dm(DHK, Rand) 2262 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2263 sm_next_responding_state(connection); 2264 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2265 return; 2266 2267 case SM_PH3_DISTRIBUTE_KEYS: 2268 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2269 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2270 uint8_t buffer[17]; 2271 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2272 reverse_128(setup->sm_ltk, &buffer[1]); 2273 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2274 sm_timeout_reset(connection); 2275 return; 2276 } 2277 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2278 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2279 uint8_t buffer[11]; 2280 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2281 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2282 reverse_64(setup->sm_local_rand, &buffer[3]); 2283 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2284 sm_timeout_reset(connection); 2285 return; 2286 } 2287 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2288 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2289 uint8_t buffer[17]; 2290 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2291 reverse_128(sm_persistent_irk, &buffer[1]); 2292 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2293 sm_timeout_reset(connection); 2294 return; 2295 } 2296 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2297 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2298 bd_addr_t local_address; 2299 uint8_t buffer[8]; 2300 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2301 gap_advertisements_get_address(&buffer[1], local_address); 2302 reverse_bd_addr(local_address, &buffer[2]); 2303 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2304 sm_timeout_reset(connection); 2305 return; 2306 } 2307 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2308 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2309 2310 // hack to reproduce test runs 2311 if (test_use_fixed_local_csrk){ 2312 memset(setup->sm_local_csrk, 0xcc, 16); 2313 } 2314 2315 uint8_t buffer[17]; 2316 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2317 reverse_128(setup->sm_local_csrk, &buffer[1]); 2318 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2319 sm_timeout_reset(connection); 2320 return; 2321 } 2322 2323 // keys are sent 2324 if (connection->sm_role){ 2325 // slave -> receive master keys if any 2326 if (sm_key_distribution_all_received(connection)){ 2327 sm_key_distribution_handle_all_received(connection); 2328 connection->sm_engine_state = SM_RESPONDER_IDLE; 2329 sm_done_for_handle(connection->sm_handle); 2330 } else { 2331 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2332 } 2333 } else { 2334 // master -> all done 2335 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2336 sm_done_for_handle(connection->sm_handle); 2337 } 2338 break; 2339 2340 default: 2341 break; 2342 } 2343 2344 // check again if active connection was released 2345 if (sm_active_connection) break; 2346 } 2347 } 2348 2349 // note: aes engine is ready as we just got the aes result 2350 static void sm_handle_encryption_result(uint8_t * data){ 2351 2352 sm_aes128_state = SM_AES128_IDLE; 2353 2354 if (sm_address_resolution_ah_calculation_active){ 2355 sm_address_resolution_ah_calculation_active = 0; 2356 // compare calulated address against connecting device 2357 uint8_t hash[3]; 2358 reverse_24(data, hash); 2359 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2360 log_info("LE Device Lookup: matched resolvable private address"); 2361 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2362 return; 2363 } 2364 // no match, try next 2365 sm_address_resolution_test++; 2366 return; 2367 } 2368 2369 switch (dkg_state){ 2370 case DKG_W4_IRK: 2371 reverse_128(data, sm_persistent_irk); 2372 log_info_key("irk", sm_persistent_irk); 2373 dkg_next_state(); 2374 return; 2375 case DKG_W4_DHK: 2376 reverse_128(data, sm_persistent_dhk); 2377 log_info_key("dhk", sm_persistent_dhk); 2378 dkg_next_state(); 2379 // SM Init Finished 2380 return; 2381 default: 2382 break; 2383 } 2384 2385 switch (rau_state){ 2386 case RAU_W4_ENC: 2387 reverse_24(data, &sm_random_address[3]); 2388 rau_next_state(); 2389 return; 2390 default: 2391 break; 2392 } 2393 2394 switch (sm_cmac_state){ 2395 case CMAC_W4_SUBKEYS: 2396 case CMAC_W4_MI: 2397 case CMAC_W4_MLAST: 2398 { 2399 sm_key_t t; 2400 reverse_128(data, t); 2401 sm_cmac_handle_encryption_result(t); 2402 } 2403 return; 2404 default: 2405 break; 2406 } 2407 2408 // retrieve sm_connection provided to sm_aes128_start_encryption 2409 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2410 if (!connection) return; 2411 switch (connection->sm_engine_state){ 2412 case SM_PH2_C1_W4_ENC_A: 2413 case SM_PH2_C1_W4_ENC_C: 2414 { 2415 sm_key_t t2; 2416 reverse_128(data, t2); 2417 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2418 } 2419 sm_next_responding_state(connection); 2420 return; 2421 case SM_PH2_C1_W4_ENC_B: 2422 reverse_128(data, setup->sm_local_confirm); 2423 log_info_key("c1!", setup->sm_local_confirm); 2424 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2425 return; 2426 case SM_PH2_C1_W4_ENC_D: 2427 { 2428 sm_key_t peer_confirm_test; 2429 reverse_128(data, peer_confirm_test); 2430 log_info_key("c1!", peer_confirm_test); 2431 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2432 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2433 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2434 return; 2435 } 2436 if (connection->sm_role){ 2437 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2438 } else { 2439 connection->sm_engine_state = SM_PH2_CALC_STK; 2440 } 2441 } 2442 return; 2443 case SM_PH2_W4_STK: 2444 reverse_128(data, setup->sm_ltk); 2445 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2446 log_info_key("stk", setup->sm_ltk); 2447 if (connection->sm_role){ 2448 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2449 } else { 2450 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2451 } 2452 return; 2453 case SM_PH3_Y_W4_ENC:{ 2454 sm_key_t y128; 2455 reverse_128(data, y128); 2456 setup->sm_local_y = big_endian_read_16(y128, 14); 2457 log_info_hex16("y", setup->sm_local_y); 2458 // PH3B3 - calculate EDIV 2459 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2460 log_info_hex16("ediv", setup->sm_local_ediv); 2461 // PH3B4 - calculate LTK - enc 2462 // LTK = d1(ER, DIV, 0)) 2463 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2464 return; 2465 } 2466 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2467 sm_key_t y128; 2468 reverse_128(data, y128); 2469 setup->sm_local_y = big_endian_read_16(y128, 14); 2470 log_info_hex16("y", setup->sm_local_y); 2471 2472 // PH3B3 - calculate DIV 2473 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2474 log_info_hex16("ediv", setup->sm_local_ediv); 2475 // PH3B4 - calculate LTK - enc 2476 // LTK = d1(ER, DIV, 0)) 2477 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2478 return; 2479 } 2480 case SM_PH3_LTK_W4_ENC: 2481 reverse_128(data, setup->sm_ltk); 2482 log_info_key("ltk", setup->sm_ltk); 2483 // calc CSRK next 2484 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2485 return; 2486 case SM_PH3_CSRK_W4_ENC: 2487 reverse_128(data, setup->sm_local_csrk); 2488 log_info_key("csrk", setup->sm_local_csrk); 2489 if (setup->sm_key_distribution_send_set){ 2490 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2491 } else { 2492 // no keys to send, just continue 2493 if (connection->sm_role){ 2494 // slave -> receive master keys 2495 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2496 } else { 2497 // master -> all done 2498 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2499 sm_done_for_handle(connection->sm_handle); 2500 } 2501 } 2502 return; 2503 case SM_RESPONDER_PH4_LTK_W4_ENC: 2504 reverse_128(data, setup->sm_ltk); 2505 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2506 log_info_key("ltk", setup->sm_ltk); 2507 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2508 return; 2509 default: 2510 break; 2511 } 2512 } 2513 2514 #ifdef USE_MBEDTLS_FOR_ECDH 2515 2516 static void sm_log_ec_keypair(void){ 2517 // print keypair 2518 char buffer[100]; 2519 size_t len; 2520 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 2521 log_info("d: %s", buffer); 2522 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 2523 log_info("X: %s", buffer); 2524 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 2525 log_info("Y: %s", buffer); 2526 } 2527 2528 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2529 int offset = setup->sm_passkey_bit; 2530 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2531 while (size) { 2532 if (offset < 32){ 2533 *buffer++ = setup->sm_peer_qx[offset++]; 2534 } else { 2535 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2536 } 2537 size--; 2538 } 2539 setup->sm_passkey_bit = offset; 2540 return 0; 2541 } 2542 #endif 2543 2544 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2545 static void sm_handle_random_result(uint8_t * data){ 2546 2547 #ifdef USE_MBEDTLS_FOR_ECDH 2548 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2549 int num_bytes = setup->sm_passkey_bit; 2550 if (num_bytes < 32){ 2551 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2552 } else { 2553 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2554 } 2555 num_bytes += 8; 2556 setup->sm_passkey_bit = num_bytes; 2557 2558 if (num_bytes >= 64){ 2559 // generate EC key 2560 setup->sm_passkey_bit = 0; 2561 mbedtls_ecp_gen_key(MBEDTLS_ECP_DP_SECP256R1, &le_keypair, &sm_generate_f_rng, NULL); 2562 sm_log_ec_keypair(); 2563 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2564 } 2565 } 2566 #endif 2567 2568 switch (rau_state){ 2569 case RAU_W4_RANDOM: 2570 // non-resolvable vs. resolvable 2571 switch (gap_random_adress_type){ 2572 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2573 // resolvable: use random as prand and calc address hash 2574 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2575 memcpy(sm_random_address, data, 3); 2576 sm_random_address[0] &= 0x3f; 2577 sm_random_address[0] |= 0x40; 2578 rau_state = RAU_GET_ENC; 2579 break; 2580 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2581 default: 2582 // "The two most significant bits of the address shall be equal to ‘0’"" 2583 memcpy(sm_random_address, data, 6); 2584 sm_random_address[0] &= 0x3f; 2585 rau_state = RAU_SET_ADDRESS; 2586 break; 2587 } 2588 return; 2589 default: 2590 break; 2591 } 2592 2593 // retrieve sm_connection provided to sm_random_start 2594 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2595 if (!connection) return; 2596 switch (connection->sm_engine_state){ 2597 case SM_PH2_W4_RANDOM_TK: 2598 { 2599 // map random to 0-999999 without speding much cycles on a modulus operation 2600 uint32_t tk = little_endian_read_32(data,0); 2601 tk = tk & 0xfffff; // 1048575 2602 if (tk >= 999999){ 2603 tk = tk - 999999; 2604 } 2605 sm_reset_tk(); 2606 big_endian_store_32(setup->sm_tk, 12, tk); 2607 if (connection->sm_role){ 2608 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2609 } else { 2610 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2611 sm_trigger_user_response(connection); 2612 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2613 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2614 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2615 } 2616 } 2617 return; 2618 } 2619 case SM_PH2_C1_W4_RANDOM_A: 2620 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2621 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2622 return; 2623 case SM_PH2_C1_W4_RANDOM_B: 2624 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2625 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2626 return; 2627 case SM_PH3_W4_RANDOM: 2628 reverse_64(data, setup->sm_local_rand); 2629 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2630 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2631 // no db for authenticated flag hack: store flag in bit 4 of LSB 2632 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2633 connection->sm_engine_state = SM_PH3_GET_DIV; 2634 return; 2635 case SM_PH3_W4_DIV: 2636 // use 16 bit from random value as div 2637 setup->sm_local_div = big_endian_read_16(data, 0); 2638 log_info_hex16("div", setup->sm_local_div); 2639 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2640 return; 2641 default: 2642 break; 2643 } 2644 } 2645 2646 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2647 2648 sm_connection_t * sm_conn; 2649 hci_con_handle_t con_handle; 2650 2651 switch (packet_type) { 2652 2653 case HCI_EVENT_PACKET: 2654 switch (hci_event_packet_get_type(packet)) { 2655 2656 case BTSTACK_EVENT_STATE: 2657 // bt stack activated, get started 2658 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2659 log_info("HCI Working!"); 2660 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2661 rau_state = RAU_IDLE; 2662 #ifdef USE_MBEDTLS_FOR_ECDH 2663 if (!test_use_fixed_ec_keypair){ 2664 setup->sm_passkey_bit = 0; 2665 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2666 } 2667 #endif 2668 sm_run(); 2669 } 2670 break; 2671 2672 case HCI_EVENT_LE_META: 2673 switch (packet[2]) { 2674 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2675 2676 log_info("sm: connected"); 2677 2678 if (packet[3]) return; // connection failed 2679 2680 con_handle = little_endian_read_16(packet, 4); 2681 sm_conn = sm_get_connection_for_handle(con_handle); 2682 if (!sm_conn) break; 2683 2684 sm_conn->sm_handle = con_handle; 2685 sm_conn->sm_role = packet[6]; 2686 sm_conn->sm_peer_addr_type = packet[7]; 2687 reverse_bd_addr(&packet[8], 2688 sm_conn->sm_peer_address); 2689 2690 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2691 2692 // reset security properties 2693 sm_conn->sm_connection_encrypted = 0; 2694 sm_conn->sm_connection_authenticated = 0; 2695 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2696 sm_conn->sm_le_db_index = -1; 2697 2698 // prepare CSRK lookup (does not involve setup) 2699 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2700 2701 // just connected -> everything else happens in sm_run() 2702 if (sm_conn->sm_role){ 2703 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2704 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2705 if (sm_slave_request_security) { 2706 // request security if requested by app 2707 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2708 } else { 2709 // otherwise, wait for pairing request 2710 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2711 } 2712 } 2713 break; 2714 } else { 2715 // master 2716 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2717 } 2718 break; 2719 2720 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2721 con_handle = little_endian_read_16(packet, 3); 2722 sm_conn = sm_get_connection_for_handle(con_handle); 2723 if (!sm_conn) break; 2724 2725 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2726 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2727 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2728 break; 2729 } 2730 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2731 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2732 break; 2733 } 2734 2735 // assume that we don't have a LTK for ediv == 0 and random == null 2736 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2737 log_info("LTK Request: ediv & random are empty"); 2738 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2739 break; 2740 } 2741 2742 // store rand and ediv 2743 reverse_64(&packet[5], sm_conn->sm_local_rand); 2744 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2745 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2746 break; 2747 2748 default: 2749 break; 2750 } 2751 break; 2752 2753 case HCI_EVENT_ENCRYPTION_CHANGE: 2754 con_handle = little_endian_read_16(packet, 3); 2755 sm_conn = sm_get_connection_for_handle(con_handle); 2756 if (!sm_conn) break; 2757 2758 sm_conn->sm_connection_encrypted = packet[5]; 2759 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2760 sm_conn->sm_actual_encryption_key_size); 2761 log_info("event handler, state %u", sm_conn->sm_engine_state); 2762 if (!sm_conn->sm_connection_encrypted) break; 2763 // continue if part of initial pairing 2764 switch (sm_conn->sm_engine_state){ 2765 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2766 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2767 sm_done_for_handle(sm_conn->sm_handle); 2768 break; 2769 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2770 if (sm_conn->sm_role){ 2771 // slave 2772 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2773 } else { 2774 // master 2775 if (sm_key_distribution_all_received(sm_conn)){ 2776 // skip receiving keys as there are none 2777 sm_key_distribution_handle_all_received(sm_conn); 2778 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2779 } else { 2780 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2781 } 2782 } 2783 break; 2784 default: 2785 break; 2786 } 2787 break; 2788 2789 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2790 con_handle = little_endian_read_16(packet, 3); 2791 sm_conn = sm_get_connection_for_handle(con_handle); 2792 if (!sm_conn) break; 2793 2794 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2795 log_info("event handler, state %u", sm_conn->sm_engine_state); 2796 // continue if part of initial pairing 2797 switch (sm_conn->sm_engine_state){ 2798 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2799 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2800 sm_done_for_handle(sm_conn->sm_handle); 2801 break; 2802 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2803 if (sm_conn->sm_role){ 2804 // slave 2805 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2806 } else { 2807 // master 2808 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2809 } 2810 break; 2811 default: 2812 break; 2813 } 2814 break; 2815 2816 2817 case HCI_EVENT_DISCONNECTION_COMPLETE: 2818 con_handle = little_endian_read_16(packet, 3); 2819 sm_done_for_handle(con_handle); 2820 sm_conn = sm_get_connection_for_handle(con_handle); 2821 if (!sm_conn) break; 2822 2823 // delete stored bonding on disconnect with authentication failure in ph0 2824 if (sm_conn->sm_role == 0 2825 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2826 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2827 le_device_db_remove(sm_conn->sm_le_db_index); 2828 } 2829 2830 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2831 sm_conn->sm_handle = 0; 2832 break; 2833 2834 case HCI_EVENT_COMMAND_COMPLETE: 2835 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2836 sm_handle_encryption_result(&packet[6]); 2837 break; 2838 } 2839 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2840 sm_handle_random_result(&packet[6]); 2841 break; 2842 } 2843 break; 2844 default: 2845 break; 2846 } 2847 break; 2848 default: 2849 break; 2850 } 2851 2852 sm_run(); 2853 } 2854 2855 static inline int sm_calc_actual_encryption_key_size(int other){ 2856 if (other < sm_min_encryption_key_size) return 0; 2857 if (other < sm_max_encryption_key_size) return other; 2858 return sm_max_encryption_key_size; 2859 } 2860 2861 static int sm_passkey_used(stk_generation_method_t method){ 2862 switch (method){ 2863 case PK_RESP_INPUT: 2864 case PK_INIT_INPUT: 2865 case OK_BOTH_INPUT: 2866 return 1; 2867 default: 2868 return 0; 2869 } 2870 } 2871 2872 /** 2873 * @return ok 2874 */ 2875 static int sm_validate_stk_generation_method(void){ 2876 // check if STK generation method is acceptable by client 2877 switch (setup->sm_stk_generation_method){ 2878 case JUST_WORKS: 2879 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2880 case PK_RESP_INPUT: 2881 case PK_INIT_INPUT: 2882 case OK_BOTH_INPUT: 2883 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2884 case OOB: 2885 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2886 case NK_BOTH_INPUT: 2887 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2888 return 1; 2889 default: 2890 return 0; 2891 } 2892 } 2893 2894 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2895 2896 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2897 sm_run(); 2898 } 2899 2900 if (packet_type != SM_DATA_PACKET) return; 2901 2902 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2903 if (!sm_conn) return; 2904 2905 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2906 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2907 return; 2908 } 2909 2910 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2911 2912 int err; 2913 2914 switch (sm_conn->sm_engine_state){ 2915 2916 // a sm timeout requries a new physical connection 2917 case SM_GENERAL_TIMEOUT: 2918 return; 2919 2920 // Initiator 2921 case SM_INITIATOR_CONNECTED: 2922 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2923 sm_pdu_received_in_wrong_state(sm_conn); 2924 break; 2925 } 2926 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2927 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2928 break; 2929 } 2930 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2931 uint16_t ediv; 2932 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2933 if (ediv){ 2934 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2935 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2936 } else { 2937 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2938 } 2939 break; 2940 } 2941 // otherwise, store security request 2942 sm_conn->sm_security_request_received = 1; 2943 break; 2944 2945 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2946 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2947 sm_pdu_received_in_wrong_state(sm_conn); 2948 break; 2949 } 2950 // store pairing request 2951 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2952 err = sm_stk_generation_init(sm_conn); 2953 if (err){ 2954 setup->sm_pairing_failed_reason = err; 2955 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2956 break; 2957 } 2958 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2959 if (setup->sm_use_secure_connections){ 2960 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2961 if (setup->sm_stk_generation_method == JUST_WORKS){ 2962 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2963 sm_trigger_user_response(sm_conn); 2964 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2965 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2966 } 2967 } else { 2968 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2969 } 2970 break; 2971 } 2972 #endif 2973 // generate random number first, if we need to show passkey 2974 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2975 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2976 break; 2977 } 2978 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2979 sm_trigger_user_response(sm_conn); 2980 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2981 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2982 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2983 } 2984 break; 2985 2986 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2987 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2988 sm_pdu_received_in_wrong_state(sm_conn); 2989 break; 2990 } 2991 2992 // store s_confirm 2993 reverse_128(&packet[1], setup->sm_peer_confirm); 2994 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2995 break; 2996 2997 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2998 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2999 sm_pdu_received_in_wrong_state(sm_conn); 3000 break;; 3001 } 3002 3003 // received random value 3004 reverse_128(&packet[1], setup->sm_peer_random); 3005 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3006 break; 3007 3008 // Responder 3009 case SM_RESPONDER_IDLE: 3010 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3011 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3012 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3013 sm_pdu_received_in_wrong_state(sm_conn); 3014 break;; 3015 } 3016 3017 // store pairing request 3018 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3019 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3020 break; 3021 3022 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3023 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3024 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3025 sm_pdu_received_in_wrong_state(sm_conn); 3026 break; 3027 } 3028 3029 // store public key for DH Key calculation 3030 reverse_256(&packet[01], setup->sm_peer_qx); 3031 reverse_256(&packet[33], setup->sm_peer_qy); 3032 3033 #ifdef USE_MBEDTLS_FOR_ECDH 3034 // validate public key 3035 mbedtls_ecp_group grp; 3036 mbedtls_ecp_group_init( &grp ); 3037 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 3038 3039 mbedtls_ecp_point Q; 3040 mbedtls_ecp_point_init( &Q ); 3041 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3042 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3043 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3044 err = mbedtls_ecp_check_pubkey(&grp, &Q); 3045 if (err){ 3046 log_error("sm: peer public key invalid %x", err); 3047 // uses "unspecified reason", there is no "public key invalid" error code 3048 sm_pdu_received_in_wrong_state(sm_conn); 3049 break; 3050 } 3051 #endif 3052 if (sm_conn->sm_role){ 3053 // responder 3054 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3055 } else { 3056 // initiator 3057 // stk generation method 3058 // passkey entry: notify app to show passkey or to request passkey 3059 switch (setup->sm_stk_generation_method){ 3060 case JUST_WORKS: 3061 case NK_BOTH_INPUT: 3062 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3063 break; 3064 case PK_INIT_INPUT: 3065 case PK_RESP_INPUT: 3066 case OK_BOTH_INPUT: 3067 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3068 break; 3069 case OOB: 3070 // TODO: implement SC OOB 3071 break; 3072 } 3073 } 3074 break; 3075 3076 case SM_SC_W4_CONFIRMATION: 3077 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3078 sm_pdu_received_in_wrong_state(sm_conn); 3079 break; 3080 } 3081 // received confirm value 3082 reverse_128(&packet[1], setup->sm_peer_confirm); 3083 3084 if (sm_conn->sm_role){ 3085 // responder 3086 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3087 } else { 3088 // initiator 3089 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3090 } 3091 break; 3092 3093 case SM_SC_W4_PAIRING_RANDOM: 3094 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3095 sm_pdu_received_in_wrong_state(sm_conn); 3096 break; 3097 } 3098 3099 // received random value 3100 reverse_128(&packet[1], setup->sm_peer_nonce); 3101 3102 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3103 // only check for JUST WORK/NC in initiator role AND passkey entry 3104 int passkey_entry = sm_passkey_used(setup->sm_stk_generation_method); 3105 if (sm_conn->sm_role || passkey_entry) { 3106 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3107 } 3108 3109 sm_sc_state_after_receiving_random(sm_conn); 3110 break; 3111 3112 case SM_SC_W2_CALCULATE_G2: 3113 case SM_SC_W4_CALCULATE_G2: 3114 case SM_SC_W2_CALCULATE_F5_SALT: 3115 case SM_SC_W4_CALCULATE_F5_SALT: 3116 case SM_SC_W2_CALCULATE_F5_MACKEY: 3117 case SM_SC_W4_CALCULATE_F5_MACKEY: 3118 case SM_SC_W2_CALCULATE_F5_LTK: 3119 case SM_SC_W4_CALCULATE_F5_LTK: 3120 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3121 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3122 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3123 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3124 sm_pdu_received_in_wrong_state(sm_conn); 3125 break; 3126 } 3127 // store DHKey Check 3128 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3129 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3130 3131 // have we been only waiting for dhkey check command? 3132 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3133 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3134 } 3135 break; 3136 #endif 3137 3138 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3139 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3140 sm_pdu_received_in_wrong_state(sm_conn); 3141 break; 3142 } 3143 3144 // received confirm value 3145 reverse_128(&packet[1], setup->sm_peer_confirm); 3146 3147 // notify client to hide shown passkey 3148 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3149 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3150 } 3151 3152 // handle user cancel pairing? 3153 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3154 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3155 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3156 break; 3157 } 3158 3159 // wait for user action? 3160 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3161 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3162 break; 3163 } 3164 3165 // calculate and send local_confirm 3166 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3167 break; 3168 3169 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3170 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3171 sm_pdu_received_in_wrong_state(sm_conn); 3172 break;; 3173 } 3174 3175 // received random value 3176 reverse_128(&packet[1], setup->sm_peer_random); 3177 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3178 break; 3179 3180 case SM_PH3_RECEIVE_KEYS: 3181 switch(packet[0]){ 3182 case SM_CODE_ENCRYPTION_INFORMATION: 3183 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3184 reverse_128(&packet[1], setup->sm_peer_ltk); 3185 break; 3186 3187 case SM_CODE_MASTER_IDENTIFICATION: 3188 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3189 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3190 reverse_64(&packet[3], setup->sm_peer_rand); 3191 break; 3192 3193 case SM_CODE_IDENTITY_INFORMATION: 3194 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3195 reverse_128(&packet[1], setup->sm_peer_irk); 3196 break; 3197 3198 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3199 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3200 setup->sm_peer_addr_type = packet[1]; 3201 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3202 break; 3203 3204 case SM_CODE_SIGNING_INFORMATION: 3205 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3206 reverse_128(&packet[1], setup->sm_peer_csrk); 3207 break; 3208 default: 3209 // Unexpected PDU 3210 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3211 break; 3212 } 3213 // done with key distribution? 3214 if (sm_key_distribution_all_received(sm_conn)){ 3215 3216 sm_key_distribution_handle_all_received(sm_conn); 3217 3218 if (sm_conn->sm_role){ 3219 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3220 sm_done_for_handle(sm_conn->sm_handle); 3221 } else { 3222 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3223 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3224 if (setup->sm_use_secure_connections){ 3225 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3226 } 3227 #endif 3228 } 3229 } 3230 break; 3231 default: 3232 // Unexpected PDU 3233 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3234 break; 3235 } 3236 3237 // try to send preparared packet 3238 sm_run(); 3239 } 3240 3241 // Security Manager Client API 3242 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3243 sm_get_oob_data = get_oob_data_callback; 3244 } 3245 3246 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3247 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3248 } 3249 3250 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3251 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3252 } 3253 3254 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3255 sm_min_encryption_key_size = min_size; 3256 sm_max_encryption_key_size = max_size; 3257 } 3258 3259 void sm_set_authentication_requirements(uint8_t auth_req){ 3260 sm_auth_req = auth_req; 3261 } 3262 3263 void sm_set_io_capabilities(io_capability_t io_capability){ 3264 sm_io_capabilities = io_capability; 3265 } 3266 3267 void sm_set_request_security(int enable){ 3268 sm_slave_request_security = enable; 3269 } 3270 3271 void sm_set_er(sm_key_t er){ 3272 memcpy(sm_persistent_er, er, 16); 3273 } 3274 3275 void sm_set_ir(sm_key_t ir){ 3276 memcpy(sm_persistent_ir, ir, 16); 3277 } 3278 3279 // Testing support only 3280 void sm_test_set_irk(sm_key_t irk){ 3281 memcpy(sm_persistent_irk, irk, 16); 3282 sm_persistent_irk_ready = 1; 3283 } 3284 3285 void sm_test_use_fixed_local_csrk(void){ 3286 test_use_fixed_local_csrk = 1; 3287 } 3288 3289 void sm_init(void){ 3290 // set some (BTstack default) ER and IR 3291 int i; 3292 sm_key_t er; 3293 sm_key_t ir; 3294 for (i=0;i<16;i++){ 3295 er[i] = 0x30 + i; 3296 ir[i] = 0x90 + i; 3297 } 3298 sm_set_er(er); 3299 sm_set_ir(ir); 3300 // defaults 3301 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3302 | SM_STK_GENERATION_METHOD_OOB 3303 | SM_STK_GENERATION_METHOD_PASSKEY 3304 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3305 3306 sm_max_encryption_key_size = 16; 3307 sm_min_encryption_key_size = 7; 3308 3309 sm_cmac_state = CMAC_IDLE; 3310 dkg_state = DKG_W4_WORKING; 3311 rau_state = RAU_W4_WORKING; 3312 sm_aes128_state = SM_AES128_IDLE; 3313 sm_address_resolution_test = -1; // no private address to resolve yet 3314 sm_address_resolution_ah_calculation_active = 0; 3315 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3316 sm_address_resolution_general_queue = NULL; 3317 3318 gap_random_adress_update_period = 15 * 60 * 1000L; 3319 3320 sm_active_connection = 0; 3321 3322 test_use_fixed_local_csrk = 0; 3323 3324 // register for HCI Events from HCI 3325 hci_event_callback_registration.callback = &sm_event_packet_handler; 3326 hci_add_event_handler(&hci_event_callback_registration); 3327 3328 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3329 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3330 3331 #ifdef USE_MBEDTLS_FOR_ECDH 3332 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3333 #endif 3334 } 3335 3336 void sm_test_use_fixed_ec_keypair(void){ 3337 test_use_fixed_ec_keypair = 1; 3338 #ifdef USE_MBEDTLS_FOR_ECDH 3339 // use test keypair from spec 3340 mbedtls_ecp_keypair_init(&le_keypair); 3341 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3342 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3343 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3344 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3345 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3346 #endif 3347 } 3348 3349 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3350 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3351 if (!hci_con) return NULL; 3352 return &hci_con->sm_connection; 3353 } 3354 3355 // @returns 0 if not encrypted, 7-16 otherwise 3356 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3357 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3358 if (!sm_conn) return 0; // wrong connection 3359 if (!sm_conn->sm_connection_encrypted) return 0; 3360 return sm_conn->sm_actual_encryption_key_size; 3361 } 3362 3363 int sm_authenticated(hci_con_handle_t con_handle){ 3364 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3365 if (!sm_conn) return 0; // wrong connection 3366 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3367 return sm_conn->sm_connection_authenticated; 3368 } 3369 3370 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3371 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3372 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3373 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3374 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3375 return sm_conn->sm_connection_authorization_state; 3376 } 3377 3378 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3379 switch (sm_conn->sm_engine_state){ 3380 case SM_GENERAL_IDLE: 3381 case SM_RESPONDER_IDLE: 3382 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3383 sm_run(); 3384 break; 3385 default: 3386 break; 3387 } 3388 } 3389 3390 /** 3391 * @brief Trigger Security Request 3392 */ 3393 void sm_send_security_request(hci_con_handle_t con_handle){ 3394 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3395 if (!sm_conn) return; 3396 sm_send_security_request_for_connection(sm_conn); 3397 } 3398 3399 // request pairing 3400 void sm_request_pairing(hci_con_handle_t con_handle){ 3401 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3402 if (!sm_conn) return; // wrong connection 3403 3404 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3405 if (sm_conn->sm_role){ 3406 sm_send_security_request_for_connection(sm_conn); 3407 } else { 3408 // used as a trigger to start central/master/initiator security procedures 3409 uint16_t ediv; 3410 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3411 switch (sm_conn->sm_irk_lookup_state){ 3412 case IRK_LOOKUP_FAILED: 3413 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3414 break; 3415 case IRK_LOOKUP_SUCCEEDED: 3416 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3417 if (ediv){ 3418 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3419 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3420 } else { 3421 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3422 } 3423 break; 3424 default: 3425 sm_conn->sm_bonding_requested = 1; 3426 break; 3427 } 3428 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3429 sm_conn->sm_bonding_requested = 1; 3430 } 3431 } 3432 sm_run(); 3433 } 3434 3435 // called by client app on authorization request 3436 void sm_authorization_decline(hci_con_handle_t con_handle){ 3437 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3438 if (!sm_conn) return; // wrong connection 3439 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3440 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3441 } 3442 3443 void sm_authorization_grant(hci_con_handle_t con_handle){ 3444 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3445 if (!sm_conn) return; // wrong connection 3446 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3447 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3448 } 3449 3450 // GAP Bonding API 3451 3452 void sm_bonding_decline(hci_con_handle_t con_handle){ 3453 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3454 if (!sm_conn) return; // wrong connection 3455 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3456 3457 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3458 switch (setup->sm_stk_generation_method){ 3459 case PK_RESP_INPUT: 3460 case PK_INIT_INPUT: 3461 case OK_BOTH_INPUT: 3462 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3463 break; 3464 case NK_BOTH_INPUT: 3465 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3466 break; 3467 case JUST_WORKS: 3468 case OOB: 3469 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3470 break; 3471 } 3472 } 3473 sm_run(); 3474 } 3475 3476 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3477 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3478 if (!sm_conn) return; // wrong connection 3479 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3480 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3481 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3482 3483 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3484 if (setup->sm_use_secure_connections){ 3485 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3486 } 3487 #endif 3488 } 3489 3490 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3491 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3492 sm_sc_prepare_dhkey_check(sm_conn); 3493 } 3494 #endif 3495 3496 sm_run(); 3497 } 3498 3499 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3500 // for now, it's the same 3501 sm_just_works_confirm(con_handle); 3502 } 3503 3504 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3505 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3506 if (!sm_conn) return; // wrong connection 3507 sm_reset_tk(); 3508 big_endian_store_32(setup->sm_tk, 12, passkey); 3509 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3510 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3511 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3512 } 3513 sm_run(); 3514 } 3515 3516 /** 3517 * @brief Identify device in LE Device DB 3518 * @param handle 3519 * @returns index from le_device_db or -1 if not found/identified 3520 */ 3521 int sm_le_device_index(hci_con_handle_t con_handle ){ 3522 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3523 if (!sm_conn) return -1; 3524 return sm_conn->sm_le_db_index; 3525 } 3526 3527 // GAP LE API 3528 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3529 gap_random_address_update_stop(); 3530 gap_random_adress_type = random_address_type; 3531 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3532 gap_random_address_update_start(); 3533 gap_random_address_trigger(); 3534 } 3535 3536 gap_random_address_type_t gap_random_address_get_mode(void){ 3537 return gap_random_adress_type; 3538 } 3539 3540 void gap_random_address_set_update_period(int period_ms){ 3541 gap_random_adress_update_period = period_ms; 3542 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3543 gap_random_address_update_stop(); 3544 gap_random_address_update_start(); 3545 } 3546 3547 void gap_random_address_set(bd_addr_t addr){ 3548 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3549 memcpy(sm_random_address, addr, 6); 3550 rau_state = RAU_SET_ADDRESS; 3551 sm_run(); 3552 } 3553 3554 /* 3555 * @brief Set Advertisement Paramters 3556 * @param adv_int_min 3557 * @param adv_int_max 3558 * @param adv_type 3559 * @param direct_address_type 3560 * @param direct_address 3561 * @param channel_map 3562 * @param filter_policy 3563 * 3564 * @note own_address_type is used from gap_random_address_set_mode 3565 */ 3566 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3567 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3568 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3569 direct_address_typ, direct_address, channel_map, filter_policy); 3570 } 3571 3572