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 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 55 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 56 #else 57 #define USE_MBEDTLS_FOR_ECDH 58 #endif 59 #endif 60 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #include "mbedtls/config.h" 65 #include "mbedtls/platform.h" 66 #include "mbedtls/ecp.h" 67 #include "sm_mbedtls_allocator.h" 68 #endif 69 70 // 71 // SM internal types and globals 72 // 73 74 typedef enum { 75 DKG_W4_WORKING, 76 DKG_CALC_IRK, 77 DKG_W4_IRK, 78 DKG_CALC_DHK, 79 DKG_W4_DHK, 80 DKG_READY 81 } derived_key_generation_t; 82 83 typedef enum { 84 RAU_W4_WORKING, 85 RAU_IDLE, 86 RAU_GET_RANDOM, 87 RAU_W4_RANDOM, 88 RAU_GET_ENC, 89 RAU_W4_ENC, 90 RAU_SET_ADDRESS, 91 } random_address_update_t; 92 93 typedef enum { 94 CMAC_IDLE, 95 CMAC_CALC_SUBKEYS, 96 CMAC_W4_SUBKEYS, 97 CMAC_CALC_MI, 98 CMAC_W4_MI, 99 CMAC_CALC_MLAST, 100 CMAC_W4_MLAST 101 } cmac_state_t; 102 103 typedef enum { 104 JUST_WORKS, 105 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 106 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 107 OK_BOTH_INPUT, // Only input on both, both input PK 108 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 109 OOB // OOB available on both sides 110 } stk_generation_method_t; 111 112 typedef enum { 113 SM_USER_RESPONSE_IDLE, 114 SM_USER_RESPONSE_PENDING, 115 SM_USER_RESPONSE_CONFIRM, 116 SM_USER_RESPONSE_PASSKEY, 117 SM_USER_RESPONSE_DECLINE 118 } sm_user_response_t; 119 120 typedef enum { 121 SM_AES128_IDLE, 122 SM_AES128_ACTIVE 123 } sm_aes128_state_t; 124 125 typedef enum { 126 ADDRESS_RESOLUTION_IDLE, 127 ADDRESS_RESOLUTION_GENERAL, 128 ADDRESS_RESOLUTION_FOR_CONNECTION, 129 } address_resolution_mode_t; 130 131 typedef enum { 132 ADDRESS_RESOLUTION_SUCEEDED, 133 ADDRESS_RESOLUTION_FAILED, 134 } address_resolution_event_t; 135 136 typedef enum { 137 EC_KEY_GENERATION_IDLE, 138 EC_KEY_GENERATION_ACTIVE, 139 EC_KEY_GENERATION_DONE, 140 } ec_key_generation_state_t; 141 142 typedef enum { 143 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 144 } sm_state_var_t; 145 146 // 147 // GLOBAL DATA 148 // 149 150 static uint8_t test_use_fixed_local_csrk; 151 152 // configuration 153 static uint8_t sm_accepted_stk_generation_methods; 154 static uint8_t sm_max_encryption_key_size; 155 static uint8_t sm_min_encryption_key_size; 156 static uint8_t sm_auth_req = 0; 157 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 158 static uint8_t sm_slave_request_security; 159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 160 static uint8_t sm_have_ec_keypair; 161 #endif 162 163 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 164 static sm_key_t sm_persistent_er; 165 static sm_key_t sm_persistent_ir; 166 167 // derived from sm_persistent_ir 168 static sm_key_t sm_persistent_dhk; 169 static sm_key_t sm_persistent_irk; 170 static uint8_t sm_persistent_irk_ready = 0; // used for testing 171 static derived_key_generation_t dkg_state; 172 173 // derived from sm_persistent_er 174 // .. 175 176 // random address update 177 static random_address_update_t rau_state; 178 static bd_addr_t sm_random_address; 179 180 // CMAC Calculation: General 181 static cmac_state_t sm_cmac_state; 182 static uint16_t sm_cmac_message_len; 183 static sm_key_t sm_cmac_k; 184 static sm_key_t sm_cmac_x; 185 static sm_key_t sm_cmac_m_last; 186 static uint8_t sm_cmac_block_current; 187 static uint8_t sm_cmac_block_count; 188 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 189 static void (*sm_cmac_done_handler)(uint8_t * hash); 190 191 // CMAC for ATT Signed Writes 192 static uint8_t sm_cmac_header[3]; 193 static const uint8_t * sm_cmac_message; 194 static uint8_t sm_cmac_sign_counter[4]; 195 196 // CMAC for Secure Connection functions 197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 198 static sm_connection_t * sm_cmac_connection; 199 static uint8_t sm_cmac_sc_buffer[80]; 200 #endif 201 202 // resolvable private address lookup / CSRK calculation 203 static int sm_address_resolution_test; 204 static int sm_address_resolution_ah_calculation_active; 205 static uint8_t sm_address_resolution_addr_type; 206 static bd_addr_t sm_address_resolution_address; 207 static void * sm_address_resolution_context; 208 static address_resolution_mode_t sm_address_resolution_mode; 209 static btstack_linked_list_t sm_address_resolution_general_queue; 210 211 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 212 static sm_aes128_state_t sm_aes128_state; 213 static void * sm_aes128_context; 214 215 // random engine. store context (ususally sm_connection_t) 216 static void * sm_random_context; 217 218 // to receive hci events 219 static btstack_packet_callback_registration_t hci_event_callback_registration; 220 221 /* to dispatch sm event */ 222 static btstack_linked_list_t sm_event_handlers; 223 224 225 // Software ECDH implementation provided by mbedtls 226 #ifdef USE_MBEDTLS_FOR_ECDH 227 // group is always valid 228 static mbedtls_ecp_group mbedtls_ec_group; 229 static ec_key_generation_state_t ec_key_generation_state; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 static uint8_t ec_d[32]; 233 #ifndef HAVE_MALLOC 234 // 4304 bytes with 73 allocations 235 #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 236 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 237 #endif 238 #endif 239 240 // 241 // Volume 3, Part H, Chapter 24 242 // "Security shall be initiated by the Security Manager in the device in the master role. 243 // The device in the slave role shall be the responding device." 244 // -> master := initiator, slave := responder 245 // 246 247 // data needed for security setup 248 typedef struct sm_setup_context { 249 250 btstack_timer_source_t sm_timeout; 251 252 // used in all phases 253 uint8_t sm_pairing_failed_reason; 254 255 // user response, (Phase 1 and/or 2) 256 uint8_t sm_user_response; 257 uint8_t sm_keypress_notification; 258 259 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 260 int sm_key_distribution_send_set; 261 int sm_key_distribution_received_set; 262 263 // Phase 2 (Pairing over SMP) 264 stk_generation_method_t sm_stk_generation_method; 265 sm_key_t sm_tk; 266 uint8_t sm_use_secure_connections; 267 268 sm_key_t sm_c1_t3_value; // c1 calculation 269 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 270 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 271 sm_key_t sm_local_random; 272 sm_key_t sm_local_confirm; 273 sm_key_t sm_peer_random; 274 sm_key_t sm_peer_confirm; 275 uint8_t sm_m_addr_type; // address and type can be removed 276 uint8_t sm_s_addr_type; // '' 277 bd_addr_t sm_m_address; // '' 278 bd_addr_t sm_s_address; // '' 279 sm_key_t sm_ltk; 280 281 uint8_t sm_state_vars; 282 #ifdef ENABLE_LE_SECURE_CONNECTIONS 283 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 284 uint8_t sm_peer_qy[32]; // '' 285 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 286 sm_key_t sm_local_nonce; // might be combined with sm_local_random 287 sm_key_t sm_peer_dhkey_check; 288 sm_key_t sm_local_dhkey_check; 289 sm_key_t sm_ra; 290 sm_key_t sm_rb; 291 sm_key_t sm_t; // used for f5 and h6 292 sm_key_t sm_mackey; 293 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 294 #endif 295 296 // Phase 3 297 298 // key distribution, we generate 299 uint16_t sm_local_y; 300 uint16_t sm_local_div; 301 uint16_t sm_local_ediv; 302 uint8_t sm_local_rand[8]; 303 sm_key_t sm_local_ltk; 304 sm_key_t sm_local_csrk; 305 sm_key_t sm_local_irk; 306 // sm_local_address/addr_type not needed 307 308 // key distribution, received from peer 309 uint16_t sm_peer_y; 310 uint16_t sm_peer_div; 311 uint16_t sm_peer_ediv; 312 uint8_t sm_peer_rand[8]; 313 sm_key_t sm_peer_ltk; 314 sm_key_t sm_peer_irk; 315 sm_key_t sm_peer_csrk; 316 uint8_t sm_peer_addr_type; 317 bd_addr_t sm_peer_address; 318 319 } sm_setup_context_t; 320 321 // 322 static sm_setup_context_t the_setup; 323 static sm_setup_context_t * setup = &the_setup; 324 325 // active connection - the one for which the_setup is used for 326 static uint16_t sm_active_connection = 0; 327 328 // @returns 1 if oob data is available 329 // stores oob data in provided 16 byte buffer if not null 330 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 331 332 // horizontal: initiator capabilities 333 // vertial: responder capabilities 334 static const stk_generation_method_t stk_generation_method [5] [5] = { 335 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 336 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 337 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 338 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 339 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 340 }; 341 342 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 343 #ifdef ENABLE_LE_SECURE_CONNECTIONS 344 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 345 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 346 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 347 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 348 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 349 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 350 }; 351 #endif 352 353 static void sm_run(void); 354 static void sm_done_for_handle(hci_con_handle_t con_handle); 355 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 356 static inline int sm_calc_actual_encryption_key_size(int other); 357 static int sm_validate_stk_generation_method(void); 358 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 359 360 static void log_info_hex16(const char * name, uint16_t value){ 361 log_info("%-6s 0x%04x", name, value); 362 } 363 364 // @returns 1 if all bytes are 0 365 static int sm_is_null(uint8_t * data, int size){ 366 int i; 367 for (i=0; i < size ; i++){ 368 if (data[i]) return 0; 369 } 370 return 1; 371 } 372 373 static int sm_is_null_random(uint8_t random[8]){ 374 return sm_is_null(random, 8); 375 } 376 377 static int sm_is_null_key(uint8_t * key){ 378 return sm_is_null(key, 16); 379 } 380 381 // Key utils 382 static void sm_reset_tk(void){ 383 int i; 384 for (i=0;i<16;i++){ 385 setup->sm_tk[i] = 0; 386 } 387 } 388 389 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 390 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 391 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 392 int i; 393 for (i = max_encryption_size ; i < 16 ; i++){ 394 key[15-i] = 0; 395 } 396 } 397 398 // SMP Timeout implementation 399 400 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 401 // the Security Manager Timer shall be reset and started. 402 // 403 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 404 // 405 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 406 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 407 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 408 // established. 409 410 static void sm_timeout_handler(btstack_timer_source_t * timer){ 411 log_info("SM timeout"); 412 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 413 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 414 sm_done_for_handle(sm_conn->sm_handle); 415 416 // trigger handling of next ready connection 417 sm_run(); 418 } 419 static void sm_timeout_start(sm_connection_t * sm_conn){ 420 btstack_run_loop_remove_timer(&setup->sm_timeout); 421 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 422 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 423 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 424 btstack_run_loop_add_timer(&setup->sm_timeout); 425 } 426 static void sm_timeout_stop(void){ 427 btstack_run_loop_remove_timer(&setup->sm_timeout); 428 } 429 static void sm_timeout_reset(sm_connection_t * sm_conn){ 430 sm_timeout_stop(); 431 sm_timeout_start(sm_conn); 432 } 433 434 // end of sm timeout 435 436 // GAP Random Address updates 437 static gap_random_address_type_t gap_random_adress_type; 438 static btstack_timer_source_t gap_random_address_update_timer; 439 static uint32_t gap_random_adress_update_period; 440 441 static void gap_random_address_trigger(void){ 442 if (rau_state != RAU_IDLE) return; 443 log_info("gap_random_address_trigger"); 444 rau_state = RAU_GET_RANDOM; 445 sm_run(); 446 } 447 448 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 449 log_info("GAP Random Address Update due"); 450 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 451 btstack_run_loop_add_timer(&gap_random_address_update_timer); 452 gap_random_address_trigger(); 453 } 454 455 static void gap_random_address_update_start(void){ 456 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 457 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 458 btstack_run_loop_add_timer(&gap_random_address_update_timer); 459 } 460 461 static void gap_random_address_update_stop(void){ 462 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 463 } 464 465 466 static void sm_random_start(void * context){ 467 sm_random_context = context; 468 hci_send_cmd(&hci_le_rand); 469 } 470 471 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 472 // context is made availabe to aes128 result handler by this 473 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 474 sm_aes128_state = SM_AES128_ACTIVE; 475 sm_key_t key_flipped, plaintext_flipped; 476 reverse_128(key, key_flipped); 477 reverse_128(plaintext, plaintext_flipped); 478 sm_aes128_context = context; 479 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 480 } 481 482 // ah(k,r) helper 483 // r = padding || r 484 // r - 24 bit value 485 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 486 // r'= padding || r 487 memset(r_prime, 0, 16); 488 memcpy(&r_prime[13], r, 3); 489 } 490 491 // d1 helper 492 // d' = padding || r || d 493 // d,r - 16 bit values 494 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 495 // d'= padding || r || d 496 memset(d1_prime, 0, 16); 497 big_endian_store_16(d1_prime, 12, r); 498 big_endian_store_16(d1_prime, 14, d); 499 } 500 501 // dm helper 502 // r’ = padding || r 503 // r - 64 bit value 504 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 505 memset(r_prime, 0, 16); 506 memcpy(&r_prime[8], r, 8); 507 } 508 509 // calculate arguments for first AES128 operation in C1 function 510 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){ 511 512 // p1 = pres || preq || rat’ || iat’ 513 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 514 // cant octet of pres becomes the most significant octet of p1. 515 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 516 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 517 // p1 is 0x05000800000302070710000001010001." 518 519 sm_key_t p1; 520 reverse_56(pres, &p1[0]); 521 reverse_56(preq, &p1[7]); 522 p1[14] = rat; 523 p1[15] = iat; 524 log_info_key("p1", p1); 525 log_info_key("r", r); 526 527 // t1 = r xor p1 528 int i; 529 for (i=0;i<16;i++){ 530 t1[i] = r[i] ^ p1[i]; 531 } 532 log_info_key("t1", t1); 533 } 534 535 // calculate arguments for second AES128 operation in C1 function 536 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 537 // p2 = padding || ia || ra 538 // "The least significant octet of ra becomes the least significant octet of p2 and 539 // the most significant octet of padding becomes the most significant octet of p2. 540 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 541 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 542 543 sm_key_t p2; 544 memset(p2, 0, 16); 545 memcpy(&p2[4], ia, 6); 546 memcpy(&p2[10], ra, 6); 547 log_info_key("p2", p2); 548 549 // c1 = e(k, t2_xor_p2) 550 int i; 551 for (i=0;i<16;i++){ 552 t3[i] = t2[i] ^ p2[i]; 553 } 554 log_info_key("t3", t3); 555 } 556 557 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 558 log_info_key("r1", r1); 559 log_info_key("r2", r2); 560 memcpy(&r_prime[8], &r2[8], 8); 561 memcpy(&r_prime[0], &r1[8], 8); 562 } 563 564 #ifdef ENABLE_LE_SECURE_CONNECTIONS 565 // Software implementations of crypto toolbox for LE Secure Connection 566 // TODO: replace with code to use AES Engine of HCI Controller 567 typedef uint8_t sm_key24_t[3]; 568 typedef uint8_t sm_key56_t[7]; 569 typedef uint8_t sm_key256_t[32]; 570 571 #if 0 572 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 573 uint32_t rk[RKLENGTH(KEYBITS)]; 574 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 575 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 576 } 577 578 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 579 memcpy(k1, k0, 16); 580 sm_shift_left_by_one_bit_inplace(16, k1); 581 if (k0[0] & 0x80){ 582 k1[15] ^= 0x87; 583 } 584 memcpy(k2, k1, 16); 585 sm_shift_left_by_one_bit_inplace(16, k2); 586 if (k1[0] & 0x80){ 587 k2[15] ^= 0x87; 588 } 589 } 590 591 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 592 sm_key_t k0, k1, k2, zero; 593 memset(zero, 0, 16); 594 595 aes128_calc_cyphertext(key, zero, k0); 596 calc_subkeys(k0, k1, k2); 597 598 int cmac_block_count = (cmac_message_len + 15) / 16; 599 600 // step 3: .. 601 if (cmac_block_count==0){ 602 cmac_block_count = 1; 603 } 604 605 // step 4: set m_last 606 sm_key_t cmac_m_last; 607 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 608 int i; 609 if (sm_cmac_last_block_complete){ 610 for (i=0;i<16;i++){ 611 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 612 } 613 } else { 614 int valid_octets_in_last_block = cmac_message_len & 0x0f; 615 for (i=0;i<16;i++){ 616 if (i < valid_octets_in_last_block){ 617 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 618 continue; 619 } 620 if (i == valid_octets_in_last_block){ 621 cmac_m_last[i] = 0x80 ^ k2[i]; 622 continue; 623 } 624 cmac_m_last[i] = k2[i]; 625 } 626 } 627 628 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 629 // LOG_KEY(cmac_m_last); 630 631 // Step 5 632 sm_key_t cmac_x; 633 memset(cmac_x, 0, 16); 634 635 // Step 6 636 sm_key_t sm_cmac_y; 637 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 638 for (i=0;i<16;i++){ 639 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 640 } 641 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 642 } 643 for (i=0;i<16;i++){ 644 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 645 } 646 647 // Step 7 648 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 649 } 650 #endif 651 #endif 652 653 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){ 654 event[0] = type; 655 event[1] = event_size - 2; 656 little_endian_store_16(event, 2, con_handle); 657 event[4] = addr_type; 658 reverse_bd_addr(address, &event[5]); 659 } 660 661 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 662 // dispatch to all event handlers 663 btstack_linked_list_iterator_t it; 664 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 665 while (btstack_linked_list_iterator_has_next(&it)){ 666 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 667 entry->callback(packet_type, 0, packet, size); 668 } 669 } 670 671 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 672 uint8_t event[11]; 673 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 674 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 675 } 676 677 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){ 678 uint8_t event[15]; 679 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 680 little_endian_store_32(event, 11, passkey); 681 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 682 } 683 684 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){ 685 uint8_t event[13]; 686 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 687 little_endian_store_16(event, 11, index); 688 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 689 } 690 691 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){ 692 693 uint8_t event[18]; 694 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 695 event[11] = result; 696 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 697 } 698 699 // decide on stk generation based on 700 // - pairing request 701 // - io capabilities 702 // - OOB data availability 703 static void sm_setup_tk(void){ 704 705 // default: just works 706 setup->sm_stk_generation_method = JUST_WORKS; 707 708 #ifdef ENABLE_LE_SECURE_CONNECTIONS 709 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 710 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 711 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 712 memset(setup->sm_ra, 0, 16); 713 memset(setup->sm_rb, 0, 16); 714 #else 715 setup->sm_use_secure_connections = 0; 716 #endif 717 718 // If both devices have not set the MITM option in the Authentication Requirements 719 // Flags, then the IO capabilities shall be ignored and the Just Works association 720 // model shall be used. 721 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 722 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 723 log_info("SM: MITM not required by both -> JUST WORKS"); 724 return; 725 } 726 727 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 728 729 // If both devices have out of band authentication data, then the Authentication 730 // Requirements Flags shall be ignored when selecting the pairing method and the 731 // Out of Band pairing method shall be used. 732 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 733 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 734 log_info("SM: have OOB data"); 735 log_info_key("OOB", setup->sm_tk); 736 setup->sm_stk_generation_method = OOB; 737 return; 738 } 739 740 // Reset TK as it has been setup in sm_init_setup 741 sm_reset_tk(); 742 743 // Also use just works if unknown io capabilites 744 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)){ 745 return; 746 } 747 748 // Otherwise the IO capabilities of the devices shall be used to determine the 749 // pairing method as defined in Table 2.4. 750 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 751 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 752 753 #ifdef ENABLE_LE_SECURE_CONNECTIONS 754 // table not define by default 755 if (setup->sm_use_secure_connections){ 756 generation_method = stk_generation_method_with_secure_connection; 757 } 758 #endif 759 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)]; 760 761 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 762 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); 763 } 764 765 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 766 int flags = 0; 767 if (key_set & SM_KEYDIST_ENC_KEY){ 768 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 769 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 770 } 771 if (key_set & SM_KEYDIST_ID_KEY){ 772 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 773 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 774 } 775 if (key_set & SM_KEYDIST_SIGN){ 776 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 777 } 778 return flags; 779 } 780 781 static void sm_setup_key_distribution(uint8_t key_set){ 782 setup->sm_key_distribution_received_set = 0; 783 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 784 } 785 786 // CSRK Key Lookup 787 788 789 static int sm_address_resolution_idle(void){ 790 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 791 } 792 793 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){ 794 memcpy(sm_address_resolution_address, addr, 6); 795 sm_address_resolution_addr_type = addr_type; 796 sm_address_resolution_test = 0; 797 sm_address_resolution_mode = mode; 798 sm_address_resolution_context = context; 799 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 800 } 801 802 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 803 // check if already in list 804 btstack_linked_list_iterator_t it; 805 sm_lookup_entry_t * entry; 806 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 807 while(btstack_linked_list_iterator_has_next(&it)){ 808 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 809 if (entry->address_type != address_type) continue; 810 if (memcmp(entry->address, address, 6)) continue; 811 // already in list 812 return BTSTACK_BUSY; 813 } 814 entry = btstack_memory_sm_lookup_entry_get(); 815 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 816 entry->address_type = (bd_addr_type_t) address_type; 817 memcpy(entry->address, address, 6); 818 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 819 sm_run(); 820 return 0; 821 } 822 823 // CMAC Implementation using AES128 engine 824 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 825 int i; 826 int carry = 0; 827 for (i=len-1; i >= 0 ; i--){ 828 int new_carry = data[i] >> 7; 829 data[i] = data[i] << 1 | carry; 830 carry = new_carry; 831 } 832 } 833 834 // 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 835 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 836 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 837 } 838 static inline void dkg_next_state(void){ 839 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 840 } 841 static inline void rau_next_state(void){ 842 rau_state = (random_address_update_t) (((int)rau_state) + 1); 843 } 844 845 // CMAC calculation using AES Engine 846 847 static inline void sm_cmac_next_state(void){ 848 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 849 } 850 851 static int sm_cmac_last_block_complete(void){ 852 if (sm_cmac_message_len == 0) return 0; 853 return (sm_cmac_message_len & 0x0f) == 0; 854 } 855 856 int sm_cmac_ready(void){ 857 return sm_cmac_state == CMAC_IDLE; 858 } 859 860 // generic cmac calculation 861 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])){ 862 // Generalized CMAC 863 memcpy(sm_cmac_k, key, 16); 864 memset(sm_cmac_x, 0, 16); 865 sm_cmac_block_current = 0; 866 sm_cmac_message_len = message_len; 867 sm_cmac_done_handler = done_callback; 868 sm_cmac_get_byte = get_byte_callback; 869 870 // step 2: n := ceil(len/const_Bsize); 871 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 872 873 // step 3: .. 874 if (sm_cmac_block_count==0){ 875 sm_cmac_block_count = 1; 876 } 877 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 878 879 // first, we need to compute l for k1, k2, and m_last 880 sm_cmac_state = CMAC_CALC_SUBKEYS; 881 882 // let's go 883 sm_run(); 884 } 885 886 // cmac for ATT Message signing 887 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 888 if (offset >= sm_cmac_message_len) { 889 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 890 return 0; 891 } 892 893 offset = sm_cmac_message_len - 1 - offset; 894 895 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 896 if (offset < 3){ 897 return sm_cmac_header[offset]; 898 } 899 int actual_message_len_incl_header = sm_cmac_message_len - 4; 900 if (offset < actual_message_len_incl_header){ 901 return sm_cmac_message[offset - 3]; 902 } 903 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 904 } 905 906 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 907 // ATT Message Signing 908 sm_cmac_header[0] = opcode; 909 little_endian_store_16(sm_cmac_header, 1, con_handle); 910 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 911 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 912 sm_cmac_message = message; 913 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 914 } 915 916 917 static void sm_cmac_handle_aes_engine_ready(void){ 918 switch (sm_cmac_state){ 919 case CMAC_CALC_SUBKEYS: { 920 sm_key_t const_zero; 921 memset(const_zero, 0, 16); 922 sm_cmac_next_state(); 923 sm_aes128_start(sm_cmac_k, const_zero, NULL); 924 break; 925 } 926 case CMAC_CALC_MI: { 927 int j; 928 sm_key_t y; 929 for (j=0;j<16;j++){ 930 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 931 } 932 sm_cmac_block_current++; 933 sm_cmac_next_state(); 934 sm_aes128_start(sm_cmac_k, y, NULL); 935 break; 936 } 937 case CMAC_CALC_MLAST: { 938 int i; 939 sm_key_t y; 940 for (i=0;i<16;i++){ 941 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 942 } 943 log_info_key("Y", y); 944 sm_cmac_block_current++; 945 sm_cmac_next_state(); 946 sm_aes128_start(sm_cmac_k, y, NULL); 947 break; 948 } 949 default: 950 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 951 break; 952 } 953 } 954 955 static void sm_cmac_handle_encryption_result(sm_key_t data){ 956 switch (sm_cmac_state){ 957 case CMAC_W4_SUBKEYS: { 958 sm_key_t k1; 959 memcpy(k1, data, 16); 960 sm_shift_left_by_one_bit_inplace(16, k1); 961 if (data[0] & 0x80){ 962 k1[15] ^= 0x87; 963 } 964 sm_key_t k2; 965 memcpy(k2, k1, 16); 966 sm_shift_left_by_one_bit_inplace(16, k2); 967 if (k1[0] & 0x80){ 968 k2[15] ^= 0x87; 969 } 970 971 log_info_key("k", sm_cmac_k); 972 log_info_key("k1", k1); 973 log_info_key("k2", k2); 974 975 // step 4: set m_last 976 int i; 977 if (sm_cmac_last_block_complete()){ 978 for (i=0;i<16;i++){ 979 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 980 } 981 } else { 982 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 983 for (i=0;i<16;i++){ 984 if (i < valid_octets_in_last_block){ 985 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 986 continue; 987 } 988 if (i == valid_octets_in_last_block){ 989 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 990 continue; 991 } 992 sm_cmac_m_last[i] = k2[i]; 993 } 994 } 995 996 // next 997 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 998 break; 999 } 1000 case CMAC_W4_MI: 1001 memcpy(sm_cmac_x, data, 16); 1002 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1003 break; 1004 case CMAC_W4_MLAST: 1005 // done 1006 log_info("Setting CMAC Engine to IDLE"); 1007 sm_cmac_state = CMAC_IDLE; 1008 log_info_key("CMAC", data); 1009 sm_cmac_done_handler(data); 1010 break; 1011 default: 1012 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1013 break; 1014 } 1015 } 1016 1017 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1018 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1019 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1020 switch (setup->sm_stk_generation_method){ 1021 case PK_RESP_INPUT: 1022 if (sm_conn->sm_role){ 1023 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1024 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1025 } else { 1026 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)); 1027 } 1028 break; 1029 case PK_INIT_INPUT: 1030 if (sm_conn->sm_role){ 1031 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)); 1032 } else { 1033 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1034 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1035 } 1036 break; 1037 case OK_BOTH_INPUT: 1038 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1039 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1040 break; 1041 case NK_BOTH_INPUT: 1042 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1043 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)); 1044 break; 1045 case JUST_WORKS: 1046 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1047 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1048 break; 1049 case OOB: 1050 // client already provided OOB data, let's skip notification. 1051 break; 1052 } 1053 } 1054 1055 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1056 int recv_flags; 1057 if (sm_conn->sm_role){ 1058 // slave / responder 1059 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1060 } else { 1061 // master / initiator 1062 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1063 } 1064 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1065 return recv_flags == setup->sm_key_distribution_received_set; 1066 } 1067 1068 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1069 if (sm_active_connection == con_handle){ 1070 sm_timeout_stop(); 1071 sm_active_connection = 0; 1072 log_info("sm: connection 0x%x released setup context", con_handle); 1073 } 1074 } 1075 1076 static int sm_key_distribution_flags_for_auth_req(void){ 1077 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1078 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1079 // encryption information only if bonding requested 1080 flags |= SM_KEYDIST_ENC_KEY; 1081 } 1082 return flags; 1083 } 1084 1085 static void sm_reset_setup(void){ 1086 // fill in sm setup 1087 setup->sm_state_vars = 0; 1088 setup->sm_keypress_notification = 0xff; 1089 sm_reset_tk(); 1090 } 1091 1092 static void sm_init_setup(sm_connection_t * sm_conn){ 1093 1094 // fill in sm setup 1095 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1096 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1097 1098 // query client for OOB data 1099 int have_oob_data = 0; 1100 if (sm_get_oob_data) { 1101 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1102 } 1103 1104 sm_pairing_packet_t * local_packet; 1105 if (sm_conn->sm_role){ 1106 // slave 1107 local_packet = &setup->sm_s_pres; 1108 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1109 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1110 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1111 } else { 1112 // master 1113 local_packet = &setup->sm_m_preq; 1114 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1115 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1116 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1117 1118 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1119 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1120 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1121 } 1122 1123 uint8_t auth_req = sm_auth_req; 1124 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1125 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1126 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1127 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1128 } 1129 1130 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1131 1132 sm_pairing_packet_t * remote_packet; 1133 int remote_key_request; 1134 if (sm_conn->sm_role){ 1135 // slave / responder 1136 remote_packet = &setup->sm_m_preq; 1137 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1138 } else { 1139 // master / initiator 1140 remote_packet = &setup->sm_s_pres; 1141 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1142 } 1143 1144 // check key size 1145 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1146 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1147 1148 // decide on STK generation method 1149 sm_setup_tk(); 1150 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1151 1152 // check if STK generation method is acceptable by client 1153 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1154 1155 // identical to responder 1156 sm_setup_key_distribution(remote_key_request); 1157 1158 // JUST WORKS doens't provide authentication 1159 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1160 1161 return 0; 1162 } 1163 1164 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1165 1166 // cache and reset context 1167 int matched_device_id = sm_address_resolution_test; 1168 address_resolution_mode_t mode = sm_address_resolution_mode; 1169 void * context = sm_address_resolution_context; 1170 1171 // reset context 1172 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1173 sm_address_resolution_context = NULL; 1174 sm_address_resolution_test = -1; 1175 hci_con_handle_t con_handle = 0; 1176 1177 sm_connection_t * sm_connection; 1178 sm_key_t ltk; 1179 switch (mode){ 1180 case ADDRESS_RESOLUTION_GENERAL: 1181 break; 1182 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1183 sm_connection = (sm_connection_t *) context; 1184 con_handle = sm_connection->sm_handle; 1185 switch (event){ 1186 case ADDRESS_RESOLUTION_SUCEEDED: 1187 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1188 sm_connection->sm_le_db_index = matched_device_id; 1189 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1190 if (sm_connection->sm_role) break; 1191 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1192 sm_connection->sm_security_request_received = 0; 1193 sm_connection->sm_bonding_requested = 0; 1194 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1195 if (!sm_is_null_key(ltk)){ 1196 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1197 } else { 1198 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1199 } 1200 break; 1201 case ADDRESS_RESOLUTION_FAILED: 1202 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1203 if (sm_connection->sm_role) break; 1204 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1205 sm_connection->sm_security_request_received = 0; 1206 sm_connection->sm_bonding_requested = 0; 1207 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1208 break; 1209 } 1210 break; 1211 default: 1212 break; 1213 } 1214 1215 switch (event){ 1216 case ADDRESS_RESOLUTION_SUCEEDED: 1217 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1218 break; 1219 case ADDRESS_RESOLUTION_FAILED: 1220 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1221 break; 1222 } 1223 } 1224 1225 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1226 1227 int le_db_index = -1; 1228 1229 // lookup device based on IRK 1230 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1231 int i; 1232 for (i=0; i < le_device_db_count(); i++){ 1233 sm_key_t irk; 1234 bd_addr_t address; 1235 int address_type; 1236 le_device_db_info(i, &address_type, address, irk); 1237 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1238 log_info("sm: device found for IRK, updating"); 1239 le_db_index = i; 1240 break; 1241 } 1242 } 1243 } 1244 1245 // if not found, lookup via public address if possible 1246 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1247 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1248 int i; 1249 for (i=0; i < le_device_db_count(); i++){ 1250 bd_addr_t address; 1251 int address_type; 1252 le_device_db_info(i, &address_type, address, NULL); 1253 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1254 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1255 log_info("sm: device found for public address, updating"); 1256 le_db_index = i; 1257 break; 1258 } 1259 } 1260 } 1261 1262 // if not found, add to db 1263 if (le_db_index < 0) { 1264 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1265 } 1266 1267 if (le_db_index >= 0){ 1268 1269 // store local CSRK 1270 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1271 log_info("sm: store local CSRK"); 1272 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1273 le_device_db_local_counter_set(le_db_index, 0); 1274 } 1275 1276 // store remote CSRK 1277 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1278 log_info("sm: store remote CSRK"); 1279 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1280 le_device_db_remote_counter_set(le_db_index, 0); 1281 } 1282 1283 // store encryption information for secure connections: LTK generated by ECDH 1284 if (setup->sm_use_secure_connections){ 1285 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1286 uint8_t zero_rand[8]; 1287 memset(zero_rand, 0, 8); 1288 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1289 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1290 } 1291 1292 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1293 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1294 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1295 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1296 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1297 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1298 1299 } 1300 } 1301 1302 // keep le_db_index 1303 sm_conn->sm_le_db_index = le_db_index; 1304 } 1305 1306 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1307 setup->sm_pairing_failed_reason = reason; 1308 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1309 } 1310 1311 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1312 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1313 } 1314 1315 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1316 1317 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1318 static int sm_passkey_used(stk_generation_method_t method); 1319 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1320 1321 static void sm_log_ec_keypair(void){ 1322 log_info("Elliptic curve: d"); 1323 log_info_hexdump(ec_d,32); 1324 log_info("Elliptic curve: X"); 1325 log_info_hexdump(ec_qx,32); 1326 log_info("Elliptic curve: Y"); 1327 log_info_hexdump(ec_qy,32); 1328 } 1329 1330 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1331 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1332 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1333 } else { 1334 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1335 } 1336 } 1337 1338 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1339 if (sm_conn->sm_role){ 1340 // Responder 1341 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1342 } else { 1343 // Initiator role 1344 switch (setup->sm_stk_generation_method){ 1345 case JUST_WORKS: 1346 sm_sc_prepare_dhkey_check(sm_conn); 1347 break; 1348 1349 case NK_BOTH_INPUT: 1350 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1351 break; 1352 case PK_INIT_INPUT: 1353 case PK_RESP_INPUT: 1354 case OK_BOTH_INPUT: 1355 if (setup->sm_passkey_bit < 20) { 1356 sm_sc_start_calculating_local_confirm(sm_conn); 1357 } else { 1358 sm_sc_prepare_dhkey_check(sm_conn); 1359 } 1360 break; 1361 case OOB: 1362 // TODO: implement SC OOB 1363 break; 1364 } 1365 } 1366 } 1367 1368 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1369 return sm_cmac_sc_buffer[offset]; 1370 } 1371 1372 static void sm_sc_cmac_done(uint8_t * hash){ 1373 log_info("sm_sc_cmac_done: "); 1374 log_info_hexdump(hash, 16); 1375 1376 sm_connection_t * sm_conn = sm_cmac_connection; 1377 sm_cmac_connection = NULL; 1378 link_key_type_t link_key_type; 1379 1380 switch (sm_conn->sm_engine_state){ 1381 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1382 memcpy(setup->sm_local_confirm, hash, 16); 1383 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1384 break; 1385 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1386 // check 1387 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1388 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1389 break; 1390 } 1391 sm_sc_state_after_receiving_random(sm_conn); 1392 break; 1393 case SM_SC_W4_CALCULATE_G2: { 1394 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1395 big_endian_store_32(setup->sm_tk, 12, vab); 1396 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1397 sm_trigger_user_response(sm_conn); 1398 break; 1399 } 1400 case SM_SC_W4_CALCULATE_F5_SALT: 1401 memcpy(setup->sm_t, hash, 16); 1402 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1403 break; 1404 case SM_SC_W4_CALCULATE_F5_MACKEY: 1405 memcpy(setup->sm_mackey, hash, 16); 1406 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1407 break; 1408 case SM_SC_W4_CALCULATE_F5_LTK: 1409 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1410 // Errata Service Release to the Bluetooth Specification: ESR09 1411 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1412 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1413 memcpy(setup->sm_ltk, hash, 16); 1414 memcpy(setup->sm_local_ltk, hash, 16); 1415 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1416 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1417 break; 1418 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1419 memcpy(setup->sm_local_dhkey_check, hash, 16); 1420 if (sm_conn->sm_role){ 1421 // responder 1422 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1423 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1424 } else { 1425 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1426 } 1427 } else { 1428 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1429 } 1430 break; 1431 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1432 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1433 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1434 break; 1435 } 1436 if (sm_conn->sm_role){ 1437 // responder 1438 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1439 } else { 1440 // initiator 1441 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1442 } 1443 break; 1444 case SM_SC_W4_CALCULATE_H6_ILK: 1445 memcpy(setup->sm_t, hash, 16); 1446 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1447 break; 1448 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1449 reverse_128(hash, setup->sm_t); 1450 link_key_type = sm_conn->sm_connection_authenticated ? 1451 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1452 if (sm_conn->sm_role){ 1453 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1454 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1455 } else { 1456 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1457 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1458 } 1459 sm_done_for_handle(sm_conn->sm_handle); 1460 break; 1461 default: 1462 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1463 break; 1464 } 1465 sm_run(); 1466 } 1467 1468 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){ 1469 const uint16_t message_len = 65; 1470 sm_cmac_connection = sm_conn; 1471 memcpy(sm_cmac_sc_buffer, u, 32); 1472 memcpy(sm_cmac_sc_buffer+32, v, 32); 1473 sm_cmac_sc_buffer[64] = z; 1474 log_info("f4 key"); 1475 log_info_hexdump(x, 16); 1476 log_info("f4 message"); 1477 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1478 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1479 } 1480 1481 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1482 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1483 static const uint8_t f5_length[] = { 0x01, 0x00}; 1484 1485 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1486 #ifdef USE_MBEDTLS_FOR_ECDH 1487 // da * Pb 1488 mbedtls_mpi d; 1489 mbedtls_ecp_point Q; 1490 mbedtls_ecp_point DH; 1491 mbedtls_mpi_init(&d); 1492 mbedtls_ecp_point_init(&Q); 1493 mbedtls_ecp_point_init(&DH); 1494 mbedtls_mpi_read_binary(&d, ec_d, 32); 1495 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1496 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1497 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1498 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1499 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1500 mbedtls_mpi_free(&d); 1501 mbedtls_ecp_point_free(&Q); 1502 mbedtls_ecp_point_free(&DH); 1503 #endif 1504 log_info("dhkey"); 1505 log_info_hexdump(dhkey, 32); 1506 } 1507 1508 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1509 // calculate DHKEY 1510 sm_key256_t dhkey; 1511 sm_sc_calculate_dhkey(dhkey); 1512 1513 // calculate salt for f5 1514 const uint16_t message_len = 32; 1515 sm_cmac_connection = sm_conn; 1516 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1517 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1518 } 1519 1520 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){ 1521 const uint16_t message_len = 53; 1522 sm_cmac_connection = sm_conn; 1523 1524 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1525 sm_cmac_sc_buffer[0] = 0; 1526 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1527 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1528 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1529 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1530 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1531 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1532 log_info("f5 key"); 1533 log_info_hexdump(t, 16); 1534 log_info("f5 message for MacKey"); 1535 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1536 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1537 } 1538 1539 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1540 sm_key56_t bd_addr_master, bd_addr_slave; 1541 bd_addr_master[0] = setup->sm_m_addr_type; 1542 bd_addr_slave[0] = setup->sm_s_addr_type; 1543 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1544 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1545 if (sm_conn->sm_role){ 1546 // responder 1547 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1548 } else { 1549 // initiator 1550 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1551 } 1552 } 1553 1554 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1555 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1556 const uint16_t message_len = 53; 1557 sm_cmac_connection = sm_conn; 1558 sm_cmac_sc_buffer[0] = 1; 1559 // 1..52 setup before 1560 log_info("f5 key"); 1561 log_info_hexdump(t, 16); 1562 log_info("f5 message for LTK"); 1563 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1564 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1565 } 1566 1567 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1568 f5_ltk(sm_conn, setup->sm_t); 1569 } 1570 1571 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){ 1572 const uint16_t message_len = 65; 1573 sm_cmac_connection = sm_conn; 1574 memcpy(sm_cmac_sc_buffer, n1, 16); 1575 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1576 memcpy(sm_cmac_sc_buffer+32, r, 16); 1577 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1578 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1579 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1580 log_info("f6 key"); 1581 log_info_hexdump(w, 16); 1582 log_info("f6 message"); 1583 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1584 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1585 } 1586 1587 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1588 // - U is 256 bits 1589 // - V is 256 bits 1590 // - X is 128 bits 1591 // - Y is 128 bits 1592 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){ 1593 const uint16_t message_len = 80; 1594 sm_cmac_connection = sm_conn; 1595 memcpy(sm_cmac_sc_buffer, u, 32); 1596 memcpy(sm_cmac_sc_buffer+32, v, 32); 1597 memcpy(sm_cmac_sc_buffer+64, y, 16); 1598 log_info("g2 key"); 1599 log_info_hexdump(x, 16); 1600 log_info("g2 message"); 1601 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1602 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1603 } 1604 1605 static void g2_calculate(sm_connection_t * sm_conn) { 1606 // calc Va if numeric comparison 1607 if (sm_conn->sm_role){ 1608 // responder 1609 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1610 } else { 1611 // initiator 1612 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1613 } 1614 } 1615 1616 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1617 uint8_t z = 0; 1618 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1619 // some form of passkey 1620 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1621 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1622 setup->sm_passkey_bit++; 1623 } 1624 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1625 } 1626 1627 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1628 uint8_t z = 0; 1629 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1630 // some form of passkey 1631 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1632 // sm_passkey_bit was increased before sending confirm value 1633 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1634 } 1635 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1636 } 1637 1638 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1639 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1640 } 1641 1642 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1643 // calculate DHKCheck 1644 sm_key56_t bd_addr_master, bd_addr_slave; 1645 bd_addr_master[0] = setup->sm_m_addr_type; 1646 bd_addr_slave[0] = setup->sm_s_addr_type; 1647 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1648 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1649 uint8_t iocap_a[3]; 1650 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1651 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1652 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1653 uint8_t iocap_b[3]; 1654 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1655 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1656 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1657 if (sm_conn->sm_role){ 1658 // responder 1659 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); 1660 } else { 1661 // initiator 1662 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); 1663 } 1664 } 1665 1666 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1667 // validate E = f6() 1668 sm_key56_t bd_addr_master, bd_addr_slave; 1669 bd_addr_master[0] = setup->sm_m_addr_type; 1670 bd_addr_slave[0] = setup->sm_s_addr_type; 1671 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1672 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1673 1674 uint8_t iocap_a[3]; 1675 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1676 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1677 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1678 uint8_t iocap_b[3]; 1679 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1680 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1681 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1682 if (sm_conn->sm_role){ 1683 // responder 1684 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); 1685 } else { 1686 // initiator 1687 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); 1688 } 1689 } 1690 1691 1692 // 1693 // Link Key Conversion Function h6 1694 // 1695 // h6(W, keyID) = AES-CMACW(keyID) 1696 // - W is 128 bits 1697 // - keyID is 32 bits 1698 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1699 const uint16_t message_len = 4; 1700 sm_cmac_connection = sm_conn; 1701 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1702 log_info("h6 key"); 1703 log_info_hexdump(w, 16); 1704 log_info("h6 message"); 1705 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1706 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1707 } 1708 1709 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1710 // Errata Service Release to the Bluetooth Specification: ESR09 1711 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1712 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1713 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1714 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1715 } 1716 1717 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1718 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1719 } 1720 1721 #endif 1722 1723 // key management legacy connections: 1724 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1725 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1726 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1727 // - responder reconnects: responder uses LTK receveived from master 1728 1729 // key management secure connections: 1730 // - both devices store same LTK from ECDH key exchange. 1731 1732 static void sm_load_security_info(sm_connection_t * sm_connection){ 1733 int encryption_key_size; 1734 int authenticated; 1735 int authorized; 1736 1737 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1738 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1739 &encryption_key_size, &authenticated, &authorized); 1740 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1741 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1742 sm_connection->sm_connection_authenticated = authenticated; 1743 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1744 } 1745 1746 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1747 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1748 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1749 // re-establish used key encryption size 1750 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1751 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1752 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1753 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1754 log_info("sm: received ltk request with key size %u, authenticated %u", 1755 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1756 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1757 } 1758 1759 static void sm_run(void){ 1760 1761 btstack_linked_list_iterator_t it; 1762 1763 // assert that we can send at least commands 1764 if (!hci_can_send_command_packet_now()) return; 1765 1766 // 1767 // non-connection related behaviour 1768 // 1769 1770 // distributed key generation 1771 switch (dkg_state){ 1772 case DKG_CALC_IRK: 1773 // already busy? 1774 if (sm_aes128_state == SM_AES128_IDLE) { 1775 // IRK = d1(IR, 1, 0) 1776 sm_key_t d1_prime; 1777 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1778 dkg_next_state(); 1779 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1780 return; 1781 } 1782 break; 1783 case DKG_CALC_DHK: 1784 // already busy? 1785 if (sm_aes128_state == SM_AES128_IDLE) { 1786 // DHK = d1(IR, 3, 0) 1787 sm_key_t d1_prime; 1788 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1789 dkg_next_state(); 1790 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1791 return; 1792 } 1793 break; 1794 default: 1795 break; 1796 } 1797 1798 #ifdef USE_MBEDTLS_FOR_ECDH 1799 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1800 sm_random_start(NULL); 1801 return; 1802 } 1803 #endif 1804 1805 // random address updates 1806 switch (rau_state){ 1807 case RAU_GET_RANDOM: 1808 rau_next_state(); 1809 sm_random_start(NULL); 1810 return; 1811 case RAU_GET_ENC: 1812 // already busy? 1813 if (sm_aes128_state == SM_AES128_IDLE) { 1814 sm_key_t r_prime; 1815 sm_ah_r_prime(sm_random_address, r_prime); 1816 rau_next_state(); 1817 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1818 return; 1819 } 1820 break; 1821 case RAU_SET_ADDRESS: 1822 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1823 rau_state = RAU_IDLE; 1824 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1825 return; 1826 default: 1827 break; 1828 } 1829 1830 // CMAC 1831 switch (sm_cmac_state){ 1832 case CMAC_CALC_SUBKEYS: 1833 case CMAC_CALC_MI: 1834 case CMAC_CALC_MLAST: 1835 // already busy? 1836 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1837 sm_cmac_handle_aes_engine_ready(); 1838 return; 1839 default: 1840 break; 1841 } 1842 1843 // CSRK Lookup 1844 // -- if csrk lookup ready, find connection that require csrk lookup 1845 if (sm_address_resolution_idle()){ 1846 hci_connections_get_iterator(&it); 1847 while(btstack_linked_list_iterator_has_next(&it)){ 1848 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1849 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1850 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1851 // and start lookup 1852 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); 1853 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1854 break; 1855 } 1856 } 1857 } 1858 1859 // -- if csrk lookup ready, resolved addresses for received addresses 1860 if (sm_address_resolution_idle()) { 1861 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1862 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1863 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1864 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1865 btstack_memory_sm_lookup_entry_free(entry); 1866 } 1867 } 1868 1869 // -- Continue with CSRK device lookup by public or resolvable private address 1870 if (!sm_address_resolution_idle()){ 1871 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1872 while (sm_address_resolution_test < le_device_db_count()){ 1873 int addr_type; 1874 bd_addr_t addr; 1875 sm_key_t irk; 1876 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1877 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1878 1879 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1880 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1881 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1882 break; 1883 } 1884 1885 if (sm_address_resolution_addr_type == 0){ 1886 sm_address_resolution_test++; 1887 continue; 1888 } 1889 1890 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1891 1892 log_info("LE Device Lookup: calculate AH"); 1893 log_info_key("IRK", irk); 1894 1895 sm_key_t r_prime; 1896 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1897 sm_address_resolution_ah_calculation_active = 1; 1898 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1899 return; 1900 } 1901 1902 if (sm_address_resolution_test >= le_device_db_count()){ 1903 log_info("LE Device Lookup: not found"); 1904 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1905 } 1906 } 1907 1908 1909 // 1910 // active connection handling 1911 // -- use loop to handle next connection if lock on setup context is released 1912 1913 while (1) { 1914 1915 // Find connections that requires setup context and make active if no other is locked 1916 hci_connections_get_iterator(&it); 1917 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1918 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1919 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1920 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1921 int done = 1; 1922 int err; 1923 switch (sm_connection->sm_engine_state) { 1924 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1925 // send packet if possible, 1926 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1927 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1928 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1929 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1930 } else { 1931 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1932 } 1933 // don't lock sxetup context yet 1934 done = 0; 1935 break; 1936 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1937 sm_reset_setup(); 1938 sm_init_setup(sm_connection); 1939 // recover pairing request 1940 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1941 err = sm_stk_generation_init(sm_connection); 1942 if (err){ 1943 setup->sm_pairing_failed_reason = err; 1944 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1945 break; 1946 } 1947 sm_timeout_start(sm_connection); 1948 // generate random number first, if we need to show passkey 1949 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1950 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1951 break; 1952 } 1953 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1954 break; 1955 case SM_INITIATOR_PH0_HAS_LTK: 1956 sm_reset_setup(); 1957 sm_load_security_info(sm_connection); 1958 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1959 break; 1960 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1961 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1962 switch (sm_connection->sm_irk_lookup_state){ 1963 case IRK_LOOKUP_SUCCEEDED: 1964 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 1965 sm_reset_setup(); 1966 sm_load_security_info(sm_connection); 1967 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 1968 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 1969 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 1970 break; 1971 } 1972 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 1973 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1974 // don't lock setup context yet 1975 done = 0; 1976 break; 1977 case IRK_LOOKUP_FAILED: 1978 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1979 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1980 // don't lock setup context yet 1981 done = 0; 1982 break; 1983 default: 1984 // just wait until IRK lookup is completed 1985 // don't lock setup context yet 1986 done = 0; 1987 break; 1988 } 1989 #endif 1990 break; 1991 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1992 sm_reset_setup(); 1993 sm_init_setup(sm_connection); 1994 sm_timeout_start(sm_connection); 1995 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1996 break; 1997 default: 1998 done = 0; 1999 break; 2000 } 2001 if (done){ 2002 sm_active_connection = sm_connection->sm_handle; 2003 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2004 } 2005 } 2006 2007 // 2008 // active connection handling 2009 // 2010 2011 if (sm_active_connection == 0) return; 2012 2013 // assert that we could send a SM PDU - not needed for all of the following 2014 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2015 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2016 return; 2017 } 2018 2019 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2020 if (!connection) return; 2021 2022 // send keypress notifications 2023 if (setup->sm_keypress_notification != 0xff){ 2024 uint8_t buffer[2]; 2025 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2026 buffer[1] = setup->sm_keypress_notification; 2027 setup->sm_keypress_notification = 0xff; 2028 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2029 return; 2030 } 2031 2032 sm_key_t plaintext; 2033 int key_distribution_flags; 2034 2035 log_info("sm_run: state %u", connection->sm_engine_state); 2036 2037 // responding state 2038 switch (connection->sm_engine_state){ 2039 2040 // general 2041 case SM_GENERAL_SEND_PAIRING_FAILED: { 2042 uint8_t buffer[2]; 2043 buffer[0] = SM_CODE_PAIRING_FAILED; 2044 buffer[1] = setup->sm_pairing_failed_reason; 2045 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2046 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2047 sm_done_for_handle(connection->sm_handle); 2048 break; 2049 } 2050 2051 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2052 case SM_SC_W2_GET_RANDOM_A: 2053 sm_random_start(connection); 2054 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2055 break; 2056 case SM_SC_W2_GET_RANDOM_B: 2057 sm_random_start(connection); 2058 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2059 break; 2060 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2061 if (!sm_cmac_ready()) break; 2062 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2063 sm_sc_calculate_local_confirm(connection); 2064 break; 2065 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2066 if (!sm_cmac_ready()) break; 2067 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2068 sm_sc_calculate_remote_confirm(connection); 2069 break; 2070 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2071 if (!sm_cmac_ready()) break; 2072 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2073 sm_sc_calculate_f6_for_dhkey_check(connection); 2074 break; 2075 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2076 if (!sm_cmac_ready()) break; 2077 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2078 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2079 break; 2080 case SM_SC_W2_CALCULATE_F5_SALT: 2081 if (!sm_cmac_ready()) break; 2082 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2083 f5_calculate_salt(connection); 2084 break; 2085 case SM_SC_W2_CALCULATE_F5_MACKEY: 2086 if (!sm_cmac_ready()) break; 2087 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2088 f5_calculate_mackey(connection); 2089 break; 2090 case SM_SC_W2_CALCULATE_F5_LTK: 2091 if (!sm_cmac_ready()) break; 2092 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2093 f5_calculate_ltk(connection); 2094 break; 2095 case SM_SC_W2_CALCULATE_G2: 2096 if (!sm_cmac_ready()) break; 2097 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2098 g2_calculate(connection); 2099 break; 2100 case SM_SC_W2_CALCULATE_H6_ILK: 2101 if (!sm_cmac_ready()) break; 2102 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2103 h6_calculate_ilk(connection); 2104 break; 2105 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2106 if (!sm_cmac_ready()) break; 2107 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2108 h6_calculate_br_edr_link_key(connection); 2109 break; 2110 2111 #endif 2112 // initiator side 2113 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2114 sm_key_t peer_ltk_flipped; 2115 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2116 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2117 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2118 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2119 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2120 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2121 return; 2122 } 2123 2124 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2125 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2126 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2127 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2128 sm_timeout_reset(connection); 2129 break; 2130 2131 // responder side 2132 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2133 connection->sm_engine_state = SM_RESPONDER_IDLE; 2134 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2135 sm_done_for_handle(connection->sm_handle); 2136 return; 2137 2138 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2139 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2140 uint8_t buffer[65]; 2141 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2142 // 2143 reverse_256(ec_qx, &buffer[1]); 2144 reverse_256(ec_qy, &buffer[33]); 2145 2146 // stk generation method 2147 // passkey entry: notify app to show passkey or to request passkey 2148 switch (setup->sm_stk_generation_method){ 2149 case JUST_WORKS: 2150 case NK_BOTH_INPUT: 2151 if (connection->sm_role){ 2152 // responder 2153 sm_sc_start_calculating_local_confirm(connection); 2154 } else { 2155 // initiator 2156 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2157 } 2158 break; 2159 case PK_INIT_INPUT: 2160 case PK_RESP_INPUT: 2161 case OK_BOTH_INPUT: 2162 // use random TK for display 2163 memcpy(setup->sm_ra, setup->sm_tk, 16); 2164 memcpy(setup->sm_rb, setup->sm_tk, 16); 2165 setup->sm_passkey_bit = 0; 2166 2167 if (connection->sm_role){ 2168 // responder 2169 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2170 } else { 2171 // initiator 2172 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2173 } 2174 sm_trigger_user_response(connection); 2175 break; 2176 case OOB: 2177 // TODO: implement SC OOB 2178 break; 2179 } 2180 2181 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2182 sm_timeout_reset(connection); 2183 break; 2184 } 2185 case SM_SC_SEND_CONFIRMATION: { 2186 uint8_t buffer[17]; 2187 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2188 reverse_128(setup->sm_local_confirm, &buffer[1]); 2189 if (connection->sm_role){ 2190 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2191 } else { 2192 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2193 } 2194 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2195 sm_timeout_reset(connection); 2196 break; 2197 } 2198 case SM_SC_SEND_PAIRING_RANDOM: { 2199 uint8_t buffer[17]; 2200 buffer[0] = SM_CODE_PAIRING_RANDOM; 2201 reverse_128(setup->sm_local_nonce, &buffer[1]); 2202 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2203 if (connection->sm_role){ 2204 // responder 2205 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2206 } else { 2207 // initiator 2208 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2209 } 2210 } else { 2211 if (connection->sm_role){ 2212 // responder 2213 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2214 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2215 } else { 2216 sm_sc_prepare_dhkey_check(connection); 2217 } 2218 } else { 2219 // initiator 2220 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2221 } 2222 } 2223 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2224 sm_timeout_reset(connection); 2225 break; 2226 } 2227 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2228 uint8_t buffer[17]; 2229 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2230 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2231 2232 if (connection->sm_role){ 2233 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2234 } else { 2235 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2236 } 2237 2238 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2239 sm_timeout_reset(connection); 2240 break; 2241 } 2242 2243 #endif 2244 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2245 // echo initiator for now 2246 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2247 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2248 2249 if (setup->sm_use_secure_connections){ 2250 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2251 // skip LTK/EDIV for SC 2252 log_info("sm: dropping encryption information flag"); 2253 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2254 } else { 2255 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2256 } 2257 2258 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); 2259 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); 2260 // update key distribution after ENC was dropped 2261 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2262 2263 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2264 sm_timeout_reset(connection); 2265 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2266 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2267 sm_trigger_user_response(connection); 2268 } 2269 return; 2270 2271 case SM_PH2_SEND_PAIRING_RANDOM: { 2272 uint8_t buffer[17]; 2273 buffer[0] = SM_CODE_PAIRING_RANDOM; 2274 reverse_128(setup->sm_local_random, &buffer[1]); 2275 if (connection->sm_role){ 2276 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2277 } else { 2278 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2279 } 2280 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2281 sm_timeout_reset(connection); 2282 break; 2283 } 2284 2285 case SM_PH2_GET_RANDOM_TK: 2286 case SM_PH2_C1_GET_RANDOM_A: 2287 case SM_PH2_C1_GET_RANDOM_B: 2288 case SM_PH3_GET_RANDOM: 2289 case SM_PH3_GET_DIV: 2290 sm_next_responding_state(connection); 2291 sm_random_start(connection); 2292 return; 2293 2294 case SM_PH2_C1_GET_ENC_B: 2295 case SM_PH2_C1_GET_ENC_D: 2296 // already busy? 2297 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2298 sm_next_responding_state(connection); 2299 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2300 return; 2301 2302 case SM_PH3_LTK_GET_ENC: 2303 case SM_RESPONDER_PH4_LTK_GET_ENC: 2304 // already busy? 2305 if (sm_aes128_state == SM_AES128_IDLE) { 2306 sm_key_t d_prime; 2307 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2308 sm_next_responding_state(connection); 2309 sm_aes128_start(sm_persistent_er, d_prime, connection); 2310 return; 2311 } 2312 break; 2313 2314 case SM_PH3_CSRK_GET_ENC: 2315 // already busy? 2316 if (sm_aes128_state == SM_AES128_IDLE) { 2317 sm_key_t d_prime; 2318 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2319 sm_next_responding_state(connection); 2320 sm_aes128_start(sm_persistent_er, d_prime, connection); 2321 return; 2322 } 2323 break; 2324 2325 case SM_PH2_C1_GET_ENC_C: 2326 // already busy? 2327 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2328 // calculate m_confirm using aes128 engine - step 1 2329 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); 2330 sm_next_responding_state(connection); 2331 sm_aes128_start(setup->sm_tk, plaintext, connection); 2332 break; 2333 case SM_PH2_C1_GET_ENC_A: 2334 // already busy? 2335 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2336 // calculate confirm using aes128 engine - step 1 2337 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); 2338 sm_next_responding_state(connection); 2339 sm_aes128_start(setup->sm_tk, plaintext, connection); 2340 break; 2341 case SM_PH2_CALC_STK: 2342 // already busy? 2343 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2344 // calculate STK 2345 if (connection->sm_role){ 2346 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2347 } else { 2348 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2349 } 2350 sm_next_responding_state(connection); 2351 sm_aes128_start(setup->sm_tk, plaintext, connection); 2352 break; 2353 case SM_PH3_Y_GET_ENC: 2354 // already busy? 2355 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2356 // PH3B2 - calculate Y from - enc 2357 // Y = dm(DHK, Rand) 2358 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2359 sm_next_responding_state(connection); 2360 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2361 return; 2362 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2363 uint8_t buffer[17]; 2364 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2365 reverse_128(setup->sm_local_confirm, &buffer[1]); 2366 if (connection->sm_role){ 2367 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2368 } else { 2369 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2370 } 2371 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2372 sm_timeout_reset(connection); 2373 return; 2374 } 2375 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2376 sm_key_t stk_flipped; 2377 reverse_128(setup->sm_ltk, stk_flipped); 2378 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2379 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2380 return; 2381 } 2382 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2383 sm_key_t stk_flipped; 2384 reverse_128(setup->sm_ltk, stk_flipped); 2385 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2386 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2387 return; 2388 } 2389 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2390 sm_key_t ltk_flipped; 2391 reverse_128(setup->sm_ltk, ltk_flipped); 2392 connection->sm_engine_state = SM_RESPONDER_IDLE; 2393 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2394 return; 2395 } 2396 case SM_RESPONDER_PH4_Y_GET_ENC: 2397 // already busy? 2398 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2399 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2400 // Y = dm(DHK, Rand) 2401 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2402 sm_next_responding_state(connection); 2403 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2404 return; 2405 2406 case SM_PH3_DISTRIBUTE_KEYS: 2407 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2408 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2409 uint8_t buffer[17]; 2410 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2411 reverse_128(setup->sm_ltk, &buffer[1]); 2412 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2413 sm_timeout_reset(connection); 2414 return; 2415 } 2416 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2417 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2418 uint8_t buffer[11]; 2419 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2420 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2421 reverse_64(setup->sm_local_rand, &buffer[3]); 2422 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2423 sm_timeout_reset(connection); 2424 return; 2425 } 2426 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2427 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2428 uint8_t buffer[17]; 2429 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2430 reverse_128(sm_persistent_irk, &buffer[1]); 2431 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2432 sm_timeout_reset(connection); 2433 return; 2434 } 2435 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2436 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2437 bd_addr_t local_address; 2438 uint8_t buffer[8]; 2439 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2440 gap_advertisements_get_address(&buffer[1], local_address); 2441 reverse_bd_addr(local_address, &buffer[2]); 2442 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2443 sm_timeout_reset(connection); 2444 return; 2445 } 2446 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2447 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2448 2449 // hack to reproduce test runs 2450 if (test_use_fixed_local_csrk){ 2451 memset(setup->sm_local_csrk, 0xcc, 16); 2452 } 2453 2454 uint8_t buffer[17]; 2455 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2456 reverse_128(setup->sm_local_csrk, &buffer[1]); 2457 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2458 sm_timeout_reset(connection); 2459 return; 2460 } 2461 2462 // keys are sent 2463 if (connection->sm_role){ 2464 // slave -> receive master keys if any 2465 if (sm_key_distribution_all_received(connection)){ 2466 sm_key_distribution_handle_all_received(connection); 2467 connection->sm_engine_state = SM_RESPONDER_IDLE; 2468 sm_done_for_handle(connection->sm_handle); 2469 } else { 2470 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2471 } 2472 } else { 2473 // master -> all done 2474 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2475 sm_done_for_handle(connection->sm_handle); 2476 } 2477 break; 2478 2479 default: 2480 break; 2481 } 2482 2483 // check again if active connection was released 2484 if (sm_active_connection) break; 2485 } 2486 } 2487 2488 // note: aes engine is ready as we just got the aes result 2489 static void sm_handle_encryption_result(uint8_t * data){ 2490 2491 sm_aes128_state = SM_AES128_IDLE; 2492 2493 if (sm_address_resolution_ah_calculation_active){ 2494 sm_address_resolution_ah_calculation_active = 0; 2495 // compare calulated address against connecting device 2496 uint8_t hash[3]; 2497 reverse_24(data, hash); 2498 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2499 log_info("LE Device Lookup: matched resolvable private address"); 2500 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2501 return; 2502 } 2503 // no match, try next 2504 sm_address_resolution_test++; 2505 return; 2506 } 2507 2508 switch (dkg_state){ 2509 case DKG_W4_IRK: 2510 reverse_128(data, sm_persistent_irk); 2511 log_info_key("irk", sm_persistent_irk); 2512 dkg_next_state(); 2513 return; 2514 case DKG_W4_DHK: 2515 reverse_128(data, sm_persistent_dhk); 2516 log_info_key("dhk", sm_persistent_dhk); 2517 dkg_next_state(); 2518 // SM Init Finished 2519 return; 2520 default: 2521 break; 2522 } 2523 2524 switch (rau_state){ 2525 case RAU_W4_ENC: 2526 reverse_24(data, &sm_random_address[3]); 2527 rau_next_state(); 2528 return; 2529 default: 2530 break; 2531 } 2532 2533 switch (sm_cmac_state){ 2534 case CMAC_W4_SUBKEYS: 2535 case CMAC_W4_MI: 2536 case CMAC_W4_MLAST: 2537 { 2538 sm_key_t t; 2539 reverse_128(data, t); 2540 sm_cmac_handle_encryption_result(t); 2541 } 2542 return; 2543 default: 2544 break; 2545 } 2546 2547 // retrieve sm_connection provided to sm_aes128_start_encryption 2548 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2549 if (!connection) return; 2550 switch (connection->sm_engine_state){ 2551 case SM_PH2_C1_W4_ENC_A: 2552 case SM_PH2_C1_W4_ENC_C: 2553 { 2554 sm_key_t t2; 2555 reverse_128(data, t2); 2556 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2557 } 2558 sm_next_responding_state(connection); 2559 return; 2560 case SM_PH2_C1_W4_ENC_B: 2561 reverse_128(data, setup->sm_local_confirm); 2562 log_info_key("c1!", setup->sm_local_confirm); 2563 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2564 return; 2565 case SM_PH2_C1_W4_ENC_D: 2566 { 2567 sm_key_t peer_confirm_test; 2568 reverse_128(data, peer_confirm_test); 2569 log_info_key("c1!", peer_confirm_test); 2570 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2571 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2572 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2573 return; 2574 } 2575 if (connection->sm_role){ 2576 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2577 } else { 2578 connection->sm_engine_state = SM_PH2_CALC_STK; 2579 } 2580 } 2581 return; 2582 case SM_PH2_W4_STK: 2583 reverse_128(data, setup->sm_ltk); 2584 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2585 log_info_key("stk", setup->sm_ltk); 2586 if (connection->sm_role){ 2587 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2588 } else { 2589 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2590 } 2591 return; 2592 case SM_PH3_Y_W4_ENC:{ 2593 sm_key_t y128; 2594 reverse_128(data, y128); 2595 setup->sm_local_y = big_endian_read_16(y128, 14); 2596 log_info_hex16("y", setup->sm_local_y); 2597 // PH3B3 - calculate EDIV 2598 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2599 log_info_hex16("ediv", setup->sm_local_ediv); 2600 // PH3B4 - calculate LTK - enc 2601 // LTK = d1(ER, DIV, 0)) 2602 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2603 return; 2604 } 2605 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2606 sm_key_t y128; 2607 reverse_128(data, y128); 2608 setup->sm_local_y = big_endian_read_16(y128, 14); 2609 log_info_hex16("y", setup->sm_local_y); 2610 2611 // PH3B3 - calculate DIV 2612 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2613 log_info_hex16("ediv", setup->sm_local_ediv); 2614 // PH3B4 - calculate LTK - enc 2615 // LTK = d1(ER, DIV, 0)) 2616 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2617 return; 2618 } 2619 case SM_PH3_LTK_W4_ENC: 2620 reverse_128(data, setup->sm_ltk); 2621 log_info_key("ltk", setup->sm_ltk); 2622 // calc CSRK next 2623 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2624 return; 2625 case SM_PH3_CSRK_W4_ENC: 2626 reverse_128(data, setup->sm_local_csrk); 2627 log_info_key("csrk", setup->sm_local_csrk); 2628 if (setup->sm_key_distribution_send_set){ 2629 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2630 } else { 2631 // no keys to send, just continue 2632 if (connection->sm_role){ 2633 // slave -> receive master keys 2634 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2635 } else { 2636 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2637 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2638 } else { 2639 // master -> all done 2640 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2641 sm_done_for_handle(connection->sm_handle); 2642 } 2643 } 2644 } 2645 return; 2646 case SM_RESPONDER_PH4_LTK_W4_ENC: 2647 reverse_128(data, setup->sm_ltk); 2648 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2649 log_info_key("ltk", setup->sm_ltk); 2650 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2651 return; 2652 default: 2653 break; 2654 } 2655 } 2656 2657 #ifdef USE_MBEDTLS_FOR_ECDH 2658 2659 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2660 int offset = setup->sm_passkey_bit; 2661 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2662 while (size) { 2663 if (offset < 32){ 2664 *buffer++ = setup->sm_peer_qx[offset++]; 2665 } else { 2666 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2667 } 2668 size--; 2669 } 2670 setup->sm_passkey_bit = offset; 2671 return 0; 2672 } 2673 #endif 2674 2675 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2676 static void sm_handle_random_result(uint8_t * data){ 2677 2678 #ifdef USE_MBEDTLS_FOR_ECDH 2679 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2680 int num_bytes = setup->sm_passkey_bit; 2681 if (num_bytes < 32){ 2682 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2683 } else { 2684 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2685 } 2686 num_bytes += 8; 2687 setup->sm_passkey_bit = num_bytes; 2688 2689 if (num_bytes >= 64){ 2690 // generate EC key 2691 setup->sm_passkey_bit = 0; 2692 mbedtls_mpi d; 2693 mbedtls_ecp_point P; 2694 mbedtls_mpi_init(&d); 2695 mbedtls_ecp_point_init(&P); 2696 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2697 log_info("gen keypair %x", res); 2698 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2699 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2700 mbedtls_mpi_write_binary(&d, ec_d, 32); 2701 mbedtls_ecp_point_free(&P); 2702 mbedtls_mpi_free(&d); 2703 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2704 sm_log_ec_keypair(); 2705 2706 #if 0 2707 printf("test dhkey check\n"); 2708 sm_key256_t dhkey; 2709 memcpy(setup->sm_peer_qx, ec_qx, 32); 2710 memcpy(setup->sm_peer_qy, ec_qy, 32); 2711 sm_sc_calculate_dhkey(dhkey); 2712 #endif 2713 2714 } 2715 } 2716 #endif 2717 2718 switch (rau_state){ 2719 case RAU_W4_RANDOM: 2720 // non-resolvable vs. resolvable 2721 switch (gap_random_adress_type){ 2722 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2723 // resolvable: use random as prand and calc address hash 2724 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2725 memcpy(sm_random_address, data, 3); 2726 sm_random_address[0] &= 0x3f; 2727 sm_random_address[0] |= 0x40; 2728 rau_state = RAU_GET_ENC; 2729 break; 2730 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2731 default: 2732 // "The two most significant bits of the address shall be equal to ‘0’"" 2733 memcpy(sm_random_address, data, 6); 2734 sm_random_address[0] &= 0x3f; 2735 rau_state = RAU_SET_ADDRESS; 2736 break; 2737 } 2738 return; 2739 default: 2740 break; 2741 } 2742 2743 // retrieve sm_connection provided to sm_random_start 2744 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2745 if (!connection) return; 2746 switch (connection->sm_engine_state){ 2747 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2748 case SM_SC_W4_GET_RANDOM_A: 2749 memcpy(&setup->sm_local_nonce[0], data, 8); 2750 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2751 break; 2752 case SM_SC_W4_GET_RANDOM_B: 2753 memcpy(&setup->sm_local_nonce[8], data, 8); 2754 // initiator & jw/nc -> send pairing random 2755 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2756 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2757 break; 2758 } else { 2759 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2760 } 2761 break; 2762 #endif 2763 2764 case SM_PH2_W4_RANDOM_TK: 2765 { 2766 // map random to 0-999999 without speding much cycles on a modulus operation 2767 uint32_t tk = little_endian_read_32(data,0); 2768 tk = tk & 0xfffff; // 1048575 2769 if (tk >= 999999){ 2770 tk = tk - 999999; 2771 } 2772 sm_reset_tk(); 2773 big_endian_store_32(setup->sm_tk, 12, tk); 2774 if (connection->sm_role){ 2775 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2776 } else { 2777 if (setup->sm_use_secure_connections){ 2778 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2779 } else { 2780 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2781 sm_trigger_user_response(connection); 2782 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2783 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2784 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2785 } 2786 } 2787 } 2788 return; 2789 } 2790 case SM_PH2_C1_W4_RANDOM_A: 2791 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2792 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2793 return; 2794 case SM_PH2_C1_W4_RANDOM_B: 2795 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2796 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2797 return; 2798 case SM_PH3_W4_RANDOM: 2799 reverse_64(data, setup->sm_local_rand); 2800 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2801 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2802 // no db for authenticated flag hack: store flag in bit 4 of LSB 2803 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2804 connection->sm_engine_state = SM_PH3_GET_DIV; 2805 return; 2806 case SM_PH3_W4_DIV: 2807 // use 16 bit from random value as div 2808 setup->sm_local_div = big_endian_read_16(data, 0); 2809 log_info_hex16("div", setup->sm_local_div); 2810 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2811 return; 2812 default: 2813 break; 2814 } 2815 } 2816 2817 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2818 2819 sm_connection_t * sm_conn; 2820 hci_con_handle_t con_handle; 2821 2822 switch (packet_type) { 2823 2824 case HCI_EVENT_PACKET: 2825 switch (hci_event_packet_get_type(packet)) { 2826 2827 case BTSTACK_EVENT_STATE: 2828 // bt stack activated, get started 2829 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2830 log_info("HCI Working!"); 2831 2832 // set local addr for le device db 2833 bd_addr_t local_bd_addr; 2834 gap_local_bd_addr(local_bd_addr); 2835 le_device_db_set_local_bd_addr(local_bd_addr); 2836 2837 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2838 rau_state = RAU_IDLE; 2839 #ifdef USE_MBEDTLS_FOR_ECDH 2840 if (!sm_have_ec_keypair){ 2841 setup->sm_passkey_bit = 0; 2842 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2843 } 2844 #endif 2845 sm_run(); 2846 } 2847 break; 2848 2849 case HCI_EVENT_LE_META: 2850 switch (packet[2]) { 2851 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2852 2853 log_info("sm: connected"); 2854 2855 if (packet[3]) return; // connection failed 2856 2857 con_handle = little_endian_read_16(packet, 4); 2858 sm_conn = sm_get_connection_for_handle(con_handle); 2859 if (!sm_conn) break; 2860 2861 sm_conn->sm_handle = con_handle; 2862 sm_conn->sm_role = packet[6]; 2863 sm_conn->sm_peer_addr_type = packet[7]; 2864 reverse_bd_addr(&packet[8], 2865 sm_conn->sm_peer_address); 2866 2867 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2868 2869 // reset security properties 2870 sm_conn->sm_connection_encrypted = 0; 2871 sm_conn->sm_connection_authenticated = 0; 2872 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2873 sm_conn->sm_le_db_index = -1; 2874 2875 // prepare CSRK lookup (does not involve setup) 2876 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2877 2878 // just connected -> everything else happens in sm_run() 2879 if (sm_conn->sm_role){ 2880 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2881 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2882 if (sm_slave_request_security) { 2883 // request security if requested by app 2884 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2885 } else { 2886 // otherwise, wait for pairing request 2887 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2888 } 2889 } 2890 break; 2891 } else { 2892 // master 2893 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2894 } 2895 break; 2896 2897 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2898 con_handle = little_endian_read_16(packet, 3); 2899 sm_conn = sm_get_connection_for_handle(con_handle); 2900 if (!sm_conn) break; 2901 2902 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2903 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2904 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2905 break; 2906 } 2907 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2908 // PH2 SEND LTK as we need to exchange keys in PH3 2909 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2910 break; 2911 } 2912 2913 // store rand and ediv 2914 reverse_64(&packet[5], sm_conn->sm_local_rand); 2915 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2916 2917 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2918 // potentially stored LTK is from the master 2919 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2920 sm_start_calculating_ltk_from_ediv_and_rand(sm_conn); 2921 break; 2922 } 2923 2924 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2925 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2926 #else 2927 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2928 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2929 #endif 2930 break; 2931 2932 default: 2933 break; 2934 } 2935 break; 2936 2937 case HCI_EVENT_ENCRYPTION_CHANGE: 2938 con_handle = little_endian_read_16(packet, 3); 2939 sm_conn = sm_get_connection_for_handle(con_handle); 2940 if (!sm_conn) break; 2941 2942 sm_conn->sm_connection_encrypted = packet[5]; 2943 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2944 sm_conn->sm_actual_encryption_key_size); 2945 log_info("event handler, state %u", sm_conn->sm_engine_state); 2946 if (!sm_conn->sm_connection_encrypted) break; 2947 // continue if part of initial pairing 2948 switch (sm_conn->sm_engine_state){ 2949 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2950 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2951 sm_done_for_handle(sm_conn->sm_handle); 2952 break; 2953 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2954 if (sm_conn->sm_role){ 2955 // slave 2956 if (setup->sm_use_secure_connections){ 2957 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2958 } else { 2959 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2960 } 2961 } else { 2962 // master 2963 if (sm_key_distribution_all_received(sm_conn)){ 2964 // skip receiving keys as there are none 2965 sm_key_distribution_handle_all_received(sm_conn); 2966 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2967 } else { 2968 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2969 } 2970 } 2971 break; 2972 default: 2973 break; 2974 } 2975 break; 2976 2977 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2978 con_handle = little_endian_read_16(packet, 3); 2979 sm_conn = sm_get_connection_for_handle(con_handle); 2980 if (!sm_conn) break; 2981 2982 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2983 log_info("event handler, state %u", sm_conn->sm_engine_state); 2984 // continue if part of initial pairing 2985 switch (sm_conn->sm_engine_state){ 2986 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2987 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2988 sm_done_for_handle(sm_conn->sm_handle); 2989 break; 2990 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2991 if (sm_conn->sm_role){ 2992 // slave 2993 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2994 } else { 2995 // master 2996 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2997 } 2998 break; 2999 default: 3000 break; 3001 } 3002 break; 3003 3004 3005 case HCI_EVENT_DISCONNECTION_COMPLETE: 3006 con_handle = little_endian_read_16(packet, 3); 3007 sm_done_for_handle(con_handle); 3008 sm_conn = sm_get_connection_for_handle(con_handle); 3009 if (!sm_conn) break; 3010 3011 // delete stored bonding on disconnect with authentication failure in ph0 3012 if (sm_conn->sm_role == 0 3013 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3014 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3015 le_device_db_remove(sm_conn->sm_le_db_index); 3016 } 3017 3018 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3019 sm_conn->sm_handle = 0; 3020 break; 3021 3022 case HCI_EVENT_COMMAND_COMPLETE: 3023 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3024 sm_handle_encryption_result(&packet[6]); 3025 break; 3026 } 3027 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3028 sm_handle_random_result(&packet[6]); 3029 break; 3030 } 3031 break; 3032 default: 3033 break; 3034 } 3035 break; 3036 default: 3037 break; 3038 } 3039 3040 sm_run(); 3041 } 3042 3043 static inline int sm_calc_actual_encryption_key_size(int other){ 3044 if (other < sm_min_encryption_key_size) return 0; 3045 if (other < sm_max_encryption_key_size) return other; 3046 return sm_max_encryption_key_size; 3047 } 3048 3049 3050 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3051 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3052 switch (method){ 3053 case JUST_WORKS: 3054 case NK_BOTH_INPUT: 3055 return 1; 3056 default: 3057 return 0; 3058 } 3059 } 3060 // responder 3061 3062 static int sm_passkey_used(stk_generation_method_t method){ 3063 switch (method){ 3064 case PK_RESP_INPUT: 3065 return 1; 3066 default: 3067 return 0; 3068 } 3069 } 3070 #endif 3071 3072 /** 3073 * @return ok 3074 */ 3075 static int sm_validate_stk_generation_method(void){ 3076 // check if STK generation method is acceptable by client 3077 switch (setup->sm_stk_generation_method){ 3078 case JUST_WORKS: 3079 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3080 case PK_RESP_INPUT: 3081 case PK_INIT_INPUT: 3082 case OK_BOTH_INPUT: 3083 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3084 case OOB: 3085 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3086 case NK_BOTH_INPUT: 3087 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3088 return 1; 3089 default: 3090 return 0; 3091 } 3092 } 3093 3094 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3095 3096 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3097 sm_run(); 3098 } 3099 3100 if (packet_type != SM_DATA_PACKET) return; 3101 3102 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3103 if (!sm_conn) return; 3104 3105 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3106 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3107 return; 3108 } 3109 3110 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3111 3112 int err; 3113 3114 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3115 uint8_t buffer[5]; 3116 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3117 buffer[1] = 3; 3118 little_endian_store_16(buffer, 2, con_handle); 3119 buffer[4] = packet[1]; 3120 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3121 return; 3122 } 3123 3124 switch (sm_conn->sm_engine_state){ 3125 3126 // a sm timeout requries a new physical connection 3127 case SM_GENERAL_TIMEOUT: 3128 return; 3129 3130 // Initiator 3131 case SM_INITIATOR_CONNECTED: 3132 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3133 sm_pdu_received_in_wrong_state(sm_conn); 3134 break; 3135 } 3136 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3137 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3138 break; 3139 } 3140 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3141 sm_key_t ltk; 3142 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3143 if (!sm_is_null_key(ltk)){ 3144 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3145 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3146 } else { 3147 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3148 } 3149 break; 3150 } 3151 // otherwise, store security request 3152 sm_conn->sm_security_request_received = 1; 3153 break; 3154 3155 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3156 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3157 sm_pdu_received_in_wrong_state(sm_conn); 3158 break; 3159 } 3160 // store pairing request 3161 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3162 err = sm_stk_generation_init(sm_conn); 3163 if (err){ 3164 setup->sm_pairing_failed_reason = err; 3165 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3166 break; 3167 } 3168 3169 // generate random number first, if we need to show passkey 3170 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3171 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3172 break; 3173 } 3174 3175 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3176 if (setup->sm_use_secure_connections){ 3177 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3178 if (setup->sm_stk_generation_method == JUST_WORKS){ 3179 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3180 sm_trigger_user_response(sm_conn); 3181 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3182 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3183 } 3184 } else { 3185 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3186 } 3187 break; 3188 } 3189 #endif 3190 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3191 sm_trigger_user_response(sm_conn); 3192 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3193 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3194 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3195 } 3196 break; 3197 3198 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3199 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3200 sm_pdu_received_in_wrong_state(sm_conn); 3201 break; 3202 } 3203 3204 // store s_confirm 3205 reverse_128(&packet[1], setup->sm_peer_confirm); 3206 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3207 break; 3208 3209 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3210 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3211 sm_pdu_received_in_wrong_state(sm_conn); 3212 break;; 3213 } 3214 3215 // received random value 3216 reverse_128(&packet[1], setup->sm_peer_random); 3217 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3218 break; 3219 3220 // Responder 3221 case SM_RESPONDER_IDLE: 3222 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3223 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3224 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3225 sm_pdu_received_in_wrong_state(sm_conn); 3226 break;; 3227 } 3228 3229 // store pairing request 3230 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3231 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3232 break; 3233 3234 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3235 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3236 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3237 sm_pdu_received_in_wrong_state(sm_conn); 3238 break; 3239 } 3240 3241 // store public key for DH Key calculation 3242 reverse_256(&packet[01], setup->sm_peer_qx); 3243 reverse_256(&packet[33], setup->sm_peer_qy); 3244 3245 #ifdef USE_MBEDTLS_FOR_ECDH 3246 // validate public key 3247 mbedtls_ecp_point Q; 3248 mbedtls_ecp_point_init( &Q ); 3249 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3250 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3251 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3252 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3253 mbedtls_ecp_point_free( & Q); 3254 if (err){ 3255 log_error("sm: peer public key invalid %x", err); 3256 // uses "unspecified reason", there is no "public key invalid" error code 3257 sm_pdu_received_in_wrong_state(sm_conn); 3258 break; 3259 } 3260 3261 #endif 3262 if (sm_conn->sm_role){ 3263 // responder 3264 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3265 } else { 3266 // initiator 3267 // stk generation method 3268 // passkey entry: notify app to show passkey or to request passkey 3269 switch (setup->sm_stk_generation_method){ 3270 case JUST_WORKS: 3271 case NK_BOTH_INPUT: 3272 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3273 break; 3274 case PK_RESP_INPUT: 3275 sm_sc_start_calculating_local_confirm(sm_conn); 3276 break; 3277 case PK_INIT_INPUT: 3278 case OK_BOTH_INPUT: 3279 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3280 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3281 break; 3282 } 3283 sm_sc_start_calculating_local_confirm(sm_conn); 3284 break; 3285 case OOB: 3286 // TODO: implement SC OOB 3287 break; 3288 } 3289 } 3290 break; 3291 3292 case SM_SC_W4_CONFIRMATION: 3293 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3294 sm_pdu_received_in_wrong_state(sm_conn); 3295 break; 3296 } 3297 // received confirm value 3298 reverse_128(&packet[1], setup->sm_peer_confirm); 3299 3300 if (sm_conn->sm_role){ 3301 // responder 3302 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3303 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3304 // still waiting for passkey 3305 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3306 break; 3307 } 3308 } 3309 sm_sc_start_calculating_local_confirm(sm_conn); 3310 } else { 3311 // initiator 3312 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3313 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3314 } else { 3315 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3316 } 3317 } 3318 break; 3319 3320 case SM_SC_W4_PAIRING_RANDOM: 3321 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3322 sm_pdu_received_in_wrong_state(sm_conn); 3323 break; 3324 } 3325 3326 // received random value 3327 reverse_128(&packet[1], setup->sm_peer_nonce); 3328 3329 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3330 // only check for JUST WORK/NC in initiator role AND passkey entry 3331 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3332 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3333 } 3334 3335 sm_sc_state_after_receiving_random(sm_conn); 3336 break; 3337 3338 case SM_SC_W2_CALCULATE_G2: 3339 case SM_SC_W4_CALCULATE_G2: 3340 case SM_SC_W2_CALCULATE_F5_SALT: 3341 case SM_SC_W4_CALCULATE_F5_SALT: 3342 case SM_SC_W2_CALCULATE_F5_MACKEY: 3343 case SM_SC_W4_CALCULATE_F5_MACKEY: 3344 case SM_SC_W2_CALCULATE_F5_LTK: 3345 case SM_SC_W4_CALCULATE_F5_LTK: 3346 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3347 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3348 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3349 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3350 sm_pdu_received_in_wrong_state(sm_conn); 3351 break; 3352 } 3353 // store DHKey Check 3354 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3355 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3356 3357 // have we been only waiting for dhkey check command? 3358 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3359 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3360 } 3361 break; 3362 #endif 3363 3364 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3365 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3366 sm_pdu_received_in_wrong_state(sm_conn); 3367 break; 3368 } 3369 3370 // received confirm value 3371 reverse_128(&packet[1], setup->sm_peer_confirm); 3372 3373 // notify client to hide shown passkey 3374 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3375 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3376 } 3377 3378 // handle user cancel pairing? 3379 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3380 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3381 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3382 break; 3383 } 3384 3385 // wait for user action? 3386 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3387 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3388 break; 3389 } 3390 3391 // calculate and send local_confirm 3392 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3393 break; 3394 3395 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3396 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3397 sm_pdu_received_in_wrong_state(sm_conn); 3398 break;; 3399 } 3400 3401 // received random value 3402 reverse_128(&packet[1], setup->sm_peer_random); 3403 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3404 break; 3405 3406 case SM_PH3_RECEIVE_KEYS: 3407 switch(packet[0]){ 3408 case SM_CODE_ENCRYPTION_INFORMATION: 3409 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3410 reverse_128(&packet[1], setup->sm_peer_ltk); 3411 break; 3412 3413 case SM_CODE_MASTER_IDENTIFICATION: 3414 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3415 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3416 reverse_64(&packet[3], setup->sm_peer_rand); 3417 break; 3418 3419 case SM_CODE_IDENTITY_INFORMATION: 3420 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3421 reverse_128(&packet[1], setup->sm_peer_irk); 3422 break; 3423 3424 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3425 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3426 setup->sm_peer_addr_type = packet[1]; 3427 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3428 break; 3429 3430 case SM_CODE_SIGNING_INFORMATION: 3431 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3432 reverse_128(&packet[1], setup->sm_peer_csrk); 3433 break; 3434 default: 3435 // Unexpected PDU 3436 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3437 break; 3438 } 3439 // done with key distribution? 3440 if (sm_key_distribution_all_received(sm_conn)){ 3441 3442 sm_key_distribution_handle_all_received(sm_conn); 3443 3444 if (sm_conn->sm_role){ 3445 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3446 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3447 } else { 3448 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3449 sm_done_for_handle(sm_conn->sm_handle); 3450 } 3451 } else { 3452 if (setup->sm_use_secure_connections){ 3453 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3454 } else { 3455 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3456 } 3457 } 3458 } 3459 break; 3460 default: 3461 // Unexpected PDU 3462 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3463 break; 3464 } 3465 3466 // try to send preparared packet 3467 sm_run(); 3468 } 3469 3470 // Security Manager Client API 3471 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3472 sm_get_oob_data = get_oob_data_callback; 3473 } 3474 3475 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3476 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3477 } 3478 3479 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3480 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3481 } 3482 3483 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3484 sm_min_encryption_key_size = min_size; 3485 sm_max_encryption_key_size = max_size; 3486 } 3487 3488 void sm_set_authentication_requirements(uint8_t auth_req){ 3489 sm_auth_req = auth_req; 3490 } 3491 3492 void sm_set_io_capabilities(io_capability_t io_capability){ 3493 sm_io_capabilities = io_capability; 3494 } 3495 3496 void sm_set_request_security(int enable){ 3497 sm_slave_request_security = enable; 3498 } 3499 3500 void sm_set_er(sm_key_t er){ 3501 memcpy(sm_persistent_er, er, 16); 3502 } 3503 3504 void sm_set_ir(sm_key_t ir){ 3505 memcpy(sm_persistent_ir, ir, 16); 3506 } 3507 3508 // Testing support only 3509 void sm_test_set_irk(sm_key_t irk){ 3510 memcpy(sm_persistent_irk, irk, 16); 3511 sm_persistent_irk_ready = 1; 3512 } 3513 3514 void sm_test_use_fixed_local_csrk(void){ 3515 test_use_fixed_local_csrk = 1; 3516 } 3517 3518 void sm_init(void){ 3519 // set some (BTstack default) ER and IR 3520 int i; 3521 sm_key_t er; 3522 sm_key_t ir; 3523 for (i=0;i<16;i++){ 3524 er[i] = 0x30 + i; 3525 ir[i] = 0x90 + i; 3526 } 3527 sm_set_er(er); 3528 sm_set_ir(ir); 3529 // defaults 3530 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3531 | SM_STK_GENERATION_METHOD_OOB 3532 | SM_STK_GENERATION_METHOD_PASSKEY 3533 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3534 3535 sm_max_encryption_key_size = 16; 3536 sm_min_encryption_key_size = 7; 3537 3538 sm_cmac_state = CMAC_IDLE; 3539 dkg_state = DKG_W4_WORKING; 3540 rau_state = RAU_W4_WORKING; 3541 sm_aes128_state = SM_AES128_IDLE; 3542 sm_address_resolution_test = -1; // no private address to resolve yet 3543 sm_address_resolution_ah_calculation_active = 0; 3544 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3545 sm_address_resolution_general_queue = NULL; 3546 3547 gap_random_adress_update_period = 15 * 60 * 1000L; 3548 3549 sm_active_connection = 0; 3550 3551 test_use_fixed_local_csrk = 0; 3552 3553 // register for HCI Events from HCI 3554 hci_event_callback_registration.callback = &sm_event_packet_handler; 3555 hci_add_event_handler(&hci_event_callback_registration); 3556 3557 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3558 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3559 3560 #ifdef USE_MBEDTLS_FOR_ECDH 3561 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3562 3563 #ifndef HAVE_MALLOC 3564 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3565 #endif 3566 mbedtls_ecp_group_init(&mbedtls_ec_group); 3567 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3568 3569 #if 0 3570 // test 3571 sm_test_use_fixed_ec_keypair(); 3572 if (sm_have_ec_keypair){ 3573 printf("test dhkey check\n"); 3574 sm_key256_t dhkey; 3575 memcpy(setup->sm_peer_qx, ec_qx, 32); 3576 memcpy(setup->sm_peer_qy, ec_qy, 32); 3577 sm_sc_calculate_dhkey(dhkey); 3578 } 3579 #endif 3580 #endif 3581 } 3582 3583 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3584 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3585 memcpy(ec_qx, qx, 32); 3586 memcpy(ec_qy, qy, 32); 3587 memcpy(ec_d, d, 32); 3588 sm_have_ec_keypair = 1; 3589 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3590 #endif 3591 } 3592 3593 void sm_test_use_fixed_ec_keypair(void){ 3594 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3595 #ifdef USE_MBEDTLS_FOR_ECDH 3596 // use test keypair from spec 3597 mbedtls_mpi x; 3598 mbedtls_mpi_init(&x); 3599 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3600 mbedtls_mpi_write_binary(&x, ec_d, 32); 3601 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3602 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3603 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3604 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3605 mbedtls_mpi_free(&x); 3606 #endif 3607 sm_have_ec_keypair = 1; 3608 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3609 #endif 3610 } 3611 3612 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3613 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3614 if (!hci_con) return NULL; 3615 return &hci_con->sm_connection; 3616 } 3617 3618 // @returns 0 if not encrypted, 7-16 otherwise 3619 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3620 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3621 if (!sm_conn) return 0; // wrong connection 3622 if (!sm_conn->sm_connection_encrypted) return 0; 3623 return sm_conn->sm_actual_encryption_key_size; 3624 } 3625 3626 int sm_authenticated(hci_con_handle_t con_handle){ 3627 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3628 if (!sm_conn) return 0; // wrong connection 3629 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3630 return sm_conn->sm_connection_authenticated; 3631 } 3632 3633 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3634 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3635 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3636 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3637 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3638 return sm_conn->sm_connection_authorization_state; 3639 } 3640 3641 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3642 switch (sm_conn->sm_engine_state){ 3643 case SM_GENERAL_IDLE: 3644 case SM_RESPONDER_IDLE: 3645 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3646 sm_run(); 3647 break; 3648 default: 3649 break; 3650 } 3651 } 3652 3653 /** 3654 * @brief Trigger Security Request 3655 */ 3656 void sm_send_security_request(hci_con_handle_t con_handle){ 3657 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3658 if (!sm_conn) return; 3659 sm_send_security_request_for_connection(sm_conn); 3660 } 3661 3662 // request pairing 3663 void sm_request_pairing(hci_con_handle_t con_handle){ 3664 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3665 if (!sm_conn) return; // wrong connection 3666 3667 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3668 if (sm_conn->sm_role){ 3669 sm_send_security_request_for_connection(sm_conn); 3670 } else { 3671 // used as a trigger to start central/master/initiator security procedures 3672 uint16_t ediv; 3673 sm_key_t ltk; 3674 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3675 switch (sm_conn->sm_irk_lookup_state){ 3676 case IRK_LOOKUP_FAILED: 3677 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3678 break; 3679 case IRK_LOOKUP_SUCCEEDED: 3680 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3681 if (!sm_is_null_key(ltk) || ediv){ 3682 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3683 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3684 } else { 3685 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3686 } 3687 break; 3688 default: 3689 sm_conn->sm_bonding_requested = 1; 3690 break; 3691 } 3692 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3693 sm_conn->sm_bonding_requested = 1; 3694 } 3695 } 3696 sm_run(); 3697 } 3698 3699 // called by client app on authorization request 3700 void sm_authorization_decline(hci_con_handle_t con_handle){ 3701 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3702 if (!sm_conn) return; // wrong connection 3703 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3704 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3705 } 3706 3707 void sm_authorization_grant(hci_con_handle_t con_handle){ 3708 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3709 if (!sm_conn) return; // wrong connection 3710 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3711 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3712 } 3713 3714 // GAP Bonding API 3715 3716 void sm_bonding_decline(hci_con_handle_t con_handle){ 3717 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3718 if (!sm_conn) return; // wrong connection 3719 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3720 3721 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3722 switch (setup->sm_stk_generation_method){ 3723 case PK_RESP_INPUT: 3724 case PK_INIT_INPUT: 3725 case OK_BOTH_INPUT: 3726 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3727 break; 3728 case NK_BOTH_INPUT: 3729 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3730 break; 3731 case JUST_WORKS: 3732 case OOB: 3733 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3734 break; 3735 } 3736 } 3737 sm_run(); 3738 } 3739 3740 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3741 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3742 if (!sm_conn) return; // wrong connection 3743 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3744 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3745 if (setup->sm_use_secure_connections){ 3746 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3747 } else { 3748 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3749 } 3750 } 3751 3752 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3753 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3754 sm_sc_prepare_dhkey_check(sm_conn); 3755 } 3756 #endif 3757 3758 sm_run(); 3759 } 3760 3761 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3762 // for now, it's the same 3763 sm_just_works_confirm(con_handle); 3764 } 3765 3766 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3767 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3768 if (!sm_conn) return; // wrong connection 3769 sm_reset_tk(); 3770 big_endian_store_32(setup->sm_tk, 12, passkey); 3771 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3772 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3773 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3774 } 3775 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3776 memcpy(setup->sm_ra, setup->sm_tk, 16); 3777 memcpy(setup->sm_rb, setup->sm_tk, 16); 3778 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3779 sm_sc_start_calculating_local_confirm(sm_conn); 3780 } 3781 #endif 3782 sm_run(); 3783 } 3784 3785 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3786 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3787 if (!sm_conn) return; // wrong connection 3788 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3789 setup->sm_keypress_notification = action; 3790 sm_run(); 3791 } 3792 3793 /** 3794 * @brief Identify device in LE Device DB 3795 * @param handle 3796 * @returns index from le_device_db or -1 if not found/identified 3797 */ 3798 int sm_le_device_index(hci_con_handle_t con_handle ){ 3799 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3800 if (!sm_conn) return -1; 3801 return sm_conn->sm_le_db_index; 3802 } 3803 3804 // GAP LE API 3805 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3806 gap_random_address_update_stop(); 3807 gap_random_adress_type = random_address_type; 3808 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3809 gap_random_address_update_start(); 3810 gap_random_address_trigger(); 3811 } 3812 3813 gap_random_address_type_t gap_random_address_get_mode(void){ 3814 return gap_random_adress_type; 3815 } 3816 3817 void gap_random_address_set_update_period(int period_ms){ 3818 gap_random_adress_update_period = period_ms; 3819 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3820 gap_random_address_update_stop(); 3821 gap_random_address_update_start(); 3822 } 3823 3824 void gap_random_address_set(bd_addr_t addr){ 3825 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3826 memcpy(sm_random_address, addr, 6); 3827 rau_state = RAU_SET_ADDRESS; 3828 sm_run(); 3829 } 3830 3831 /* 3832 * @brief Set Advertisement Paramters 3833 * @param adv_int_min 3834 * @param adv_int_max 3835 * @param adv_type 3836 * @param direct_address_type 3837 * @param direct_address 3838 * @param channel_map 3839 * @param filter_policy 3840 * 3841 * @note own_address_type is used from gap_random_address_set_mode 3842 */ 3843 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3844 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3845 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3846 direct_address_typ, direct_address, channel_map, filter_policy); 3847 } 3848 3849