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_init_setup(sm_connection_t * sm_conn){ 1086 1087 // fill in sm setup 1088 setup->sm_state_vars = 0; 1089 setup->sm_keypress_notification = 0xff; 1090 sm_reset_tk(); 1091 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1092 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1093 1094 // query client for OOB data 1095 int have_oob_data = 0; 1096 if (sm_get_oob_data) { 1097 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1098 } 1099 1100 sm_pairing_packet_t * local_packet; 1101 if (sm_conn->sm_role){ 1102 // slave 1103 local_packet = &setup->sm_s_pres; 1104 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1105 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1106 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1107 } else { 1108 // master 1109 local_packet = &setup->sm_m_preq; 1110 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1111 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1112 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1113 1114 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1115 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1116 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1117 } 1118 1119 uint8_t auth_req = sm_auth_req; 1120 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1121 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1122 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1123 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1124 } 1125 1126 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1127 1128 sm_pairing_packet_t * remote_packet; 1129 int remote_key_request; 1130 if (sm_conn->sm_role){ 1131 // slave / responder 1132 remote_packet = &setup->sm_m_preq; 1133 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1134 } else { 1135 // master / initiator 1136 remote_packet = &setup->sm_s_pres; 1137 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1138 } 1139 1140 // check key size 1141 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1142 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1143 1144 // decide on STK generation method 1145 sm_setup_tk(); 1146 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1147 1148 // check if STK generation method is acceptable by client 1149 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1150 1151 // identical to responder 1152 sm_setup_key_distribution(remote_key_request); 1153 1154 // JUST WORKS doens't provide authentication 1155 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1156 1157 return 0; 1158 } 1159 1160 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1161 1162 // cache and reset context 1163 int matched_device_id = sm_address_resolution_test; 1164 address_resolution_mode_t mode = sm_address_resolution_mode; 1165 void * context = sm_address_resolution_context; 1166 1167 // reset context 1168 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1169 sm_address_resolution_context = NULL; 1170 sm_address_resolution_test = -1; 1171 hci_con_handle_t con_handle = 0; 1172 1173 sm_connection_t * sm_connection; 1174 uint16_t ediv; 1175 switch (mode){ 1176 case ADDRESS_RESOLUTION_GENERAL: 1177 break; 1178 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1179 sm_connection = (sm_connection_t *) context; 1180 con_handle = sm_connection->sm_handle; 1181 switch (event){ 1182 case ADDRESS_RESOLUTION_SUCEEDED: 1183 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1184 sm_connection->sm_le_db_index = matched_device_id; 1185 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1186 if (sm_connection->sm_role) break; 1187 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1188 sm_connection->sm_security_request_received = 0; 1189 sm_connection->sm_bonding_requested = 0; 1190 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1191 if (ediv){ 1192 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1193 } else { 1194 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1195 } 1196 break; 1197 case ADDRESS_RESOLUTION_FAILED: 1198 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1199 if (sm_connection->sm_role) break; 1200 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1201 sm_connection->sm_security_request_received = 0; 1202 sm_connection->sm_bonding_requested = 0; 1203 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1204 break; 1205 } 1206 break; 1207 default: 1208 break; 1209 } 1210 1211 switch (event){ 1212 case ADDRESS_RESOLUTION_SUCEEDED: 1213 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1214 break; 1215 case ADDRESS_RESOLUTION_FAILED: 1216 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1217 break; 1218 } 1219 } 1220 1221 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1222 1223 int le_db_index = -1; 1224 1225 // lookup device based on IRK 1226 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1227 int i; 1228 for (i=0; i < le_device_db_count(); i++){ 1229 sm_key_t irk; 1230 bd_addr_t address; 1231 int address_type; 1232 le_device_db_info(i, &address_type, address, irk); 1233 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1234 log_info("sm: device found for IRK, updating"); 1235 le_db_index = i; 1236 break; 1237 } 1238 } 1239 } 1240 1241 // if not found, lookup via public address if possible 1242 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1243 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1244 int i; 1245 for (i=0; i < le_device_db_count(); i++){ 1246 bd_addr_t address; 1247 int address_type; 1248 le_device_db_info(i, &address_type, address, NULL); 1249 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1250 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1251 log_info("sm: device found for public address, updating"); 1252 le_db_index = i; 1253 break; 1254 } 1255 } 1256 } 1257 1258 // if not found, add to db 1259 if (le_db_index < 0) { 1260 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1261 } 1262 1263 if (le_db_index >= 0){ 1264 1265 // store local CSRK 1266 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1267 log_info("sm: store local CSRK"); 1268 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1269 le_device_db_local_counter_set(le_db_index, 0); 1270 } 1271 1272 // store remote CSRK 1273 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1274 log_info("sm: store remote CSRK"); 1275 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1276 le_device_db_remote_counter_set(le_db_index, 0); 1277 } 1278 1279 // store encryption information for secure connections: LTK generated by ECDH 1280 if (setup->sm_use_secure_connections){ 1281 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1282 uint8_t zero_rand[8]; 1283 memset(zero_rand, 0, 8); 1284 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1285 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1286 } 1287 1288 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1289 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1290 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1291 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1292 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1293 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1294 1295 } 1296 } 1297 1298 // keep le_db_index 1299 sm_conn->sm_le_db_index = le_db_index; 1300 } 1301 1302 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1303 setup->sm_pairing_failed_reason = reason; 1304 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1305 } 1306 1307 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1308 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1309 } 1310 1311 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1312 1313 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1314 static int sm_passkey_used(stk_generation_method_t method); 1315 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1316 1317 static void sm_log_ec_keypair(void){ 1318 log_info("Elliptic curve: d"); 1319 log_info_hexdump(ec_d,32); 1320 log_info("Elliptic curve: X"); 1321 log_info_hexdump(ec_qx,32); 1322 log_info("Elliptic curve: Y"); 1323 log_info_hexdump(ec_qy,32); 1324 } 1325 1326 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1327 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1328 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1329 } else { 1330 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1331 } 1332 } 1333 1334 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1335 if (sm_conn->sm_role){ 1336 // Responder 1337 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1338 } else { 1339 // Initiator role 1340 switch (setup->sm_stk_generation_method){ 1341 case JUST_WORKS: 1342 sm_sc_prepare_dhkey_check(sm_conn); 1343 break; 1344 1345 case NK_BOTH_INPUT: 1346 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1347 break; 1348 case PK_INIT_INPUT: 1349 case PK_RESP_INPUT: 1350 case OK_BOTH_INPUT: 1351 if (setup->sm_passkey_bit < 20) { 1352 sm_sc_start_calculating_local_confirm(sm_conn); 1353 } else { 1354 sm_sc_prepare_dhkey_check(sm_conn); 1355 } 1356 break; 1357 case OOB: 1358 // TODO: implement SC OOB 1359 break; 1360 } 1361 } 1362 } 1363 1364 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1365 return sm_cmac_sc_buffer[offset]; 1366 } 1367 1368 static void sm_sc_cmac_done(uint8_t * hash){ 1369 log_info("sm_sc_cmac_done: "); 1370 log_info_hexdump(hash, 16); 1371 1372 sm_connection_t * sm_conn = sm_cmac_connection; 1373 sm_cmac_connection = NULL; 1374 link_key_type_t link_key_type; 1375 1376 switch (sm_conn->sm_engine_state){ 1377 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1378 memcpy(setup->sm_local_confirm, hash, 16); 1379 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1380 break; 1381 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1382 // check 1383 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1384 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1385 break; 1386 } 1387 sm_sc_state_after_receiving_random(sm_conn); 1388 break; 1389 case SM_SC_W4_CALCULATE_G2: { 1390 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1391 big_endian_store_32(setup->sm_tk, 12, vab); 1392 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1393 sm_trigger_user_response(sm_conn); 1394 break; 1395 } 1396 case SM_SC_W4_CALCULATE_F5_SALT: 1397 memcpy(setup->sm_t, hash, 16); 1398 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1399 break; 1400 case SM_SC_W4_CALCULATE_F5_MACKEY: 1401 memcpy(setup->sm_mackey, hash, 16); 1402 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1403 break; 1404 case SM_SC_W4_CALCULATE_F5_LTK: 1405 memcpy(setup->sm_ltk, hash, 16); 1406 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1407 break; 1408 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1409 memcpy(setup->sm_local_dhkey_check, hash, 16); 1410 if (sm_conn->sm_role){ 1411 // responder 1412 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1413 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1414 } else { 1415 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1416 } 1417 } else { 1418 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1419 } 1420 break; 1421 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1422 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1423 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1424 break; 1425 } 1426 if (sm_conn->sm_role){ 1427 // responder 1428 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1429 } else { 1430 // initiator 1431 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1432 } 1433 break; 1434 case SM_SC_W4_CALCULATE_H6_ILK: 1435 memcpy(setup->sm_t, hash, 16); 1436 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1437 break; 1438 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1439 reverse_128(hash, setup->sm_t); 1440 link_key_type = sm_conn->sm_connection_authenticated ? 1441 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1442 if (sm_conn->sm_role){ 1443 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1444 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1445 } else { 1446 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1447 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1448 } 1449 sm_done_for_handle(sm_conn->sm_handle); 1450 break; 1451 default: 1452 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1453 break; 1454 } 1455 sm_run(); 1456 } 1457 1458 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){ 1459 const uint16_t message_len = 65; 1460 sm_cmac_connection = sm_conn; 1461 memcpy(sm_cmac_sc_buffer, u, 32); 1462 memcpy(sm_cmac_sc_buffer+32, v, 32); 1463 sm_cmac_sc_buffer[64] = z; 1464 log_info("f4 key"); 1465 log_info_hexdump(x, 16); 1466 log_info("f4 message"); 1467 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1468 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1469 } 1470 1471 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1472 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1473 static const uint8_t f5_length[] = { 0x01, 0x00}; 1474 1475 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1476 #ifdef USE_MBEDTLS_FOR_ECDH 1477 // da * Pb 1478 mbedtls_mpi d; 1479 mbedtls_ecp_point Q; 1480 mbedtls_ecp_point DH; 1481 mbedtls_mpi_init(&d); 1482 mbedtls_ecp_point_init(&Q); 1483 mbedtls_ecp_point_init(&DH); 1484 mbedtls_mpi_read_binary(&d, ec_d, 32); 1485 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1486 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1487 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1488 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1489 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1490 mbedtls_mpi_free(&d); 1491 mbedtls_ecp_point_free(&Q); 1492 mbedtls_ecp_point_free(&DH); 1493 #endif 1494 log_info("dhkey"); 1495 log_info_hexdump(dhkey, 32); 1496 } 1497 1498 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1499 // calculate DHKEY 1500 sm_key256_t dhkey; 1501 sm_sc_calculate_dhkey(dhkey); 1502 1503 // calculate salt for f5 1504 const uint16_t message_len = 32; 1505 sm_cmac_connection = sm_conn; 1506 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1507 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1508 } 1509 1510 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){ 1511 const uint16_t message_len = 53; 1512 sm_cmac_connection = sm_conn; 1513 1514 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1515 sm_cmac_sc_buffer[0] = 0; 1516 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1517 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1518 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1519 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1520 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1521 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1522 log_info("f5 key"); 1523 log_info_hexdump(t, 16); 1524 log_info("f5 message for MacKey"); 1525 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1526 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1527 } 1528 1529 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1530 sm_key56_t bd_addr_master, bd_addr_slave; 1531 bd_addr_master[0] = setup->sm_m_addr_type; 1532 bd_addr_slave[0] = setup->sm_s_addr_type; 1533 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1534 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1535 if (sm_conn->sm_role){ 1536 // responder 1537 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1538 } else { 1539 // initiator 1540 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1541 } 1542 } 1543 1544 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1545 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1546 const uint16_t message_len = 53; 1547 sm_cmac_connection = sm_conn; 1548 sm_cmac_sc_buffer[0] = 1; 1549 // 1..52 setup before 1550 log_info("f5 key"); 1551 log_info_hexdump(t, 16); 1552 log_info("f5 message for LTK"); 1553 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1554 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1555 } 1556 1557 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1558 f5_ltk(sm_conn, setup->sm_t); 1559 } 1560 1561 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){ 1562 const uint16_t message_len = 65; 1563 sm_cmac_connection = sm_conn; 1564 memcpy(sm_cmac_sc_buffer, n1, 16); 1565 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1566 memcpy(sm_cmac_sc_buffer+32, r, 16); 1567 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1568 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1569 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1570 log_info("f6 key"); 1571 log_info_hexdump(w, 16); 1572 log_info("f6 message"); 1573 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1574 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1575 } 1576 1577 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1578 // - U is 256 bits 1579 // - V is 256 bits 1580 // - X is 128 bits 1581 // - Y is 128 bits 1582 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){ 1583 const uint16_t message_len = 80; 1584 sm_cmac_connection = sm_conn; 1585 memcpy(sm_cmac_sc_buffer, u, 32); 1586 memcpy(sm_cmac_sc_buffer+32, v, 32); 1587 memcpy(sm_cmac_sc_buffer+64, y, 16); 1588 log_info("g2 key"); 1589 log_info_hexdump(x, 16); 1590 log_info("g2 message"); 1591 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1592 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1593 } 1594 1595 static void g2_calculate(sm_connection_t * sm_conn) { 1596 // calc Va if numeric comparison 1597 if (sm_conn->sm_role){ 1598 // responder 1599 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1600 } else { 1601 // initiator 1602 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1603 } 1604 } 1605 1606 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1607 uint8_t z = 0; 1608 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1609 // some form of passkey 1610 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1611 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1612 setup->sm_passkey_bit++; 1613 } 1614 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1615 } 1616 1617 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1618 uint8_t z = 0; 1619 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1620 // some form of passkey 1621 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1622 // sm_passkey_bit was increased before sending confirm value 1623 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1624 } 1625 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1626 } 1627 1628 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1629 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1630 } 1631 1632 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1633 // calculate DHKCheck 1634 sm_key56_t bd_addr_master, bd_addr_slave; 1635 bd_addr_master[0] = setup->sm_m_addr_type; 1636 bd_addr_slave[0] = setup->sm_s_addr_type; 1637 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1638 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1639 uint8_t iocap_a[3]; 1640 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1641 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1642 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1643 uint8_t iocap_b[3]; 1644 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1645 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1646 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1647 if (sm_conn->sm_role){ 1648 // responder 1649 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1650 } else { 1651 // initiator 1652 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); 1653 } 1654 } 1655 1656 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1657 // validate E = f6() 1658 sm_key56_t bd_addr_master, bd_addr_slave; 1659 bd_addr_master[0] = setup->sm_m_addr_type; 1660 bd_addr_slave[0] = setup->sm_s_addr_type; 1661 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1662 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1663 1664 uint8_t iocap_a[3]; 1665 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1666 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1667 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1668 uint8_t iocap_b[3]; 1669 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1670 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1671 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1672 if (sm_conn->sm_role){ 1673 // responder 1674 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); 1675 } else { 1676 // initiator 1677 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); 1678 } 1679 } 1680 1681 1682 // 1683 // Link Key Conversion Function h6 1684 // 1685 // h6(W, keyID) = AES-CMACW(keyID) 1686 // - W is 128 bits 1687 // - keyID is 32 bits 1688 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1689 const uint16_t message_len = 4; 1690 sm_cmac_connection = sm_conn; 1691 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1692 log_info("h6 key"); 1693 log_info_hexdump(w, 16); 1694 log_info("h6 message"); 1695 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1696 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1697 } 1698 1699 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1700 h6_engine(sm_conn, setup->sm_ltk, 0x746D7031); // "tmp1" 1701 } 1702 1703 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1704 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1705 } 1706 1707 #endif 1708 1709 // key management legacy connections: 1710 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1711 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1712 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1713 // - responder reconnects: responder uses LTK receveived from master 1714 1715 // key management secure connections: 1716 // - both devices store same LTK from ECDH key exchange. 1717 1718 static void sm_load_security_info(sm_connection_t * sm_connection){ 1719 int encryption_key_size; 1720 int authenticated; 1721 int authorized; 1722 1723 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1724 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1725 &encryption_key_size, &authenticated, &authorized); 1726 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1727 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1728 sm_connection->sm_connection_authenticated = authenticated; 1729 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1730 } 1731 1732 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1733 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1734 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1735 // re-establish used key encryption size 1736 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1737 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1738 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1739 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1740 log_info("sm: received ltk request with key size %u, authenticated %u", 1741 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1742 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1743 } 1744 1745 static void sm_run(void){ 1746 1747 btstack_linked_list_iterator_t it; 1748 1749 // assert that we can send at least commands 1750 if (!hci_can_send_command_packet_now()) return; 1751 1752 // 1753 // non-connection related behaviour 1754 // 1755 1756 // distributed key generation 1757 switch (dkg_state){ 1758 case DKG_CALC_IRK: 1759 // already busy? 1760 if (sm_aes128_state == SM_AES128_IDLE) { 1761 // IRK = d1(IR, 1, 0) 1762 sm_key_t d1_prime; 1763 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1764 dkg_next_state(); 1765 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1766 return; 1767 } 1768 break; 1769 case DKG_CALC_DHK: 1770 // already busy? 1771 if (sm_aes128_state == SM_AES128_IDLE) { 1772 // DHK = d1(IR, 3, 0) 1773 sm_key_t d1_prime; 1774 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1775 dkg_next_state(); 1776 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1777 return; 1778 } 1779 break; 1780 default: 1781 break; 1782 } 1783 1784 #ifdef USE_MBEDTLS_FOR_ECDH 1785 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1786 sm_random_start(NULL); 1787 return; 1788 } 1789 #endif 1790 1791 // random address updates 1792 switch (rau_state){ 1793 case RAU_GET_RANDOM: 1794 rau_next_state(); 1795 sm_random_start(NULL); 1796 return; 1797 case RAU_GET_ENC: 1798 // already busy? 1799 if (sm_aes128_state == SM_AES128_IDLE) { 1800 sm_key_t r_prime; 1801 sm_ah_r_prime(sm_random_address, r_prime); 1802 rau_next_state(); 1803 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1804 return; 1805 } 1806 break; 1807 case RAU_SET_ADDRESS: 1808 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1809 rau_state = RAU_IDLE; 1810 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1811 return; 1812 default: 1813 break; 1814 } 1815 1816 // CMAC 1817 switch (sm_cmac_state){ 1818 case CMAC_CALC_SUBKEYS: 1819 case CMAC_CALC_MI: 1820 case CMAC_CALC_MLAST: 1821 // already busy? 1822 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1823 sm_cmac_handle_aes_engine_ready(); 1824 return; 1825 default: 1826 break; 1827 } 1828 1829 // CSRK Lookup 1830 // -- if csrk lookup ready, find connection that require csrk lookup 1831 if (sm_address_resolution_idle()){ 1832 hci_connections_get_iterator(&it); 1833 while(btstack_linked_list_iterator_has_next(&it)){ 1834 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1835 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1836 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1837 // and start lookup 1838 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); 1839 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1840 break; 1841 } 1842 } 1843 } 1844 1845 // -- if csrk lookup ready, resolved addresses for received addresses 1846 if (sm_address_resolution_idle()) { 1847 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1848 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1849 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1850 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1851 btstack_memory_sm_lookup_entry_free(entry); 1852 } 1853 } 1854 1855 // -- Continue with CSRK device lookup by public or resolvable private address 1856 if (!sm_address_resolution_idle()){ 1857 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1858 while (sm_address_resolution_test < le_device_db_count()){ 1859 int addr_type; 1860 bd_addr_t addr; 1861 sm_key_t irk; 1862 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1863 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1864 1865 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1866 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1867 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1868 break; 1869 } 1870 1871 if (sm_address_resolution_addr_type == 0){ 1872 sm_address_resolution_test++; 1873 continue; 1874 } 1875 1876 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1877 1878 log_info("LE Device Lookup: calculate AH"); 1879 log_info_key("IRK", irk); 1880 1881 sm_key_t r_prime; 1882 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1883 sm_address_resolution_ah_calculation_active = 1; 1884 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1885 return; 1886 } 1887 1888 if (sm_address_resolution_test >= le_device_db_count()){ 1889 log_info("LE Device Lookup: not found"); 1890 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1891 } 1892 } 1893 1894 1895 // 1896 // active connection handling 1897 // -- use loop to handle next connection if lock on setup context is released 1898 1899 while (1) { 1900 1901 // Find connections that requires setup context and make active if no other is locked 1902 hci_connections_get_iterator(&it); 1903 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1904 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1905 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1906 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1907 int done = 1; 1908 int err; 1909 switch (sm_connection->sm_engine_state) { 1910 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1911 // send packet if possible, 1912 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1913 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1914 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1915 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1916 } else { 1917 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1918 } 1919 // don't lock sxetup context yet 1920 done = 0; 1921 break; 1922 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1923 sm_init_setup(sm_connection); 1924 // recover pairing request 1925 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1926 err = sm_stk_generation_init(sm_connection); 1927 if (err){ 1928 setup->sm_pairing_failed_reason = err; 1929 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1930 break; 1931 } 1932 sm_timeout_start(sm_connection); 1933 // generate random number first, if we need to show passkey 1934 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1935 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1936 break; 1937 } 1938 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1939 break; 1940 case SM_INITIATOR_PH0_HAS_LTK: 1941 sm_load_security_info(sm_connection); 1942 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1943 break; 1944 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1945 switch (sm_connection->sm_irk_lookup_state){ 1946 case IRK_LOOKUP_SUCCEEDED:{ 1947 sm_load_security_info(sm_connection); 1948 sm_connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1949 break; 1950 } 1951 case IRK_LOOKUP_FAILED: 1952 // assume that we don't have a LTK for ediv == 0 and random == null 1953 if (sm_connection->sm_local_ediv == 0 && sm_is_null_random(sm_connection->sm_local_rand)){ 1954 log_info("LTK Request: ediv & random are empty"); 1955 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1956 // TODO: no need to lock context yet -> done = 0; 1957 break; 1958 } 1959 // re-establish previously used LTK using Rand and EDIV 1960 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 1961 break; 1962 default: 1963 // just wait until IRK lookup is completed 1964 // don't lock setup context yet 1965 done = 0; 1966 break; 1967 } 1968 break; 1969 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1970 sm_init_setup(sm_connection); 1971 sm_timeout_start(sm_connection); 1972 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1973 break; 1974 default: 1975 done = 0; 1976 break; 1977 } 1978 if (done){ 1979 sm_active_connection = sm_connection->sm_handle; 1980 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1981 } 1982 } 1983 1984 // 1985 // active connection handling 1986 // 1987 1988 if (sm_active_connection == 0) return; 1989 1990 // assert that we could send a SM PDU - not needed for all of the following 1991 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1992 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1993 return; 1994 } 1995 1996 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1997 if (!connection) return; 1998 1999 // send keypress notifications 2000 if (setup->sm_keypress_notification != 0xff){ 2001 uint8_t buffer[2]; 2002 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2003 buffer[1] = setup->sm_keypress_notification; 2004 setup->sm_keypress_notification = 0xff; 2005 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2006 } 2007 2008 sm_key_t plaintext; 2009 int key_distribution_flags; 2010 2011 log_info("sm_run: state %u", connection->sm_engine_state); 2012 2013 // responding state 2014 switch (connection->sm_engine_state){ 2015 2016 // general 2017 case SM_GENERAL_SEND_PAIRING_FAILED: { 2018 uint8_t buffer[2]; 2019 buffer[0] = SM_CODE_PAIRING_FAILED; 2020 buffer[1] = setup->sm_pairing_failed_reason; 2021 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2022 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2023 sm_done_for_handle(connection->sm_handle); 2024 break; 2025 } 2026 2027 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2028 case SM_SC_W2_GET_RANDOM_A: 2029 sm_random_start(connection); 2030 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2031 break; 2032 case SM_SC_W2_GET_RANDOM_B: 2033 sm_random_start(connection); 2034 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2035 break; 2036 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2037 if (!sm_cmac_ready()) break; 2038 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2039 sm_sc_calculate_local_confirm(connection); 2040 break; 2041 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2042 if (!sm_cmac_ready()) break; 2043 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2044 sm_sc_calculate_remote_confirm(connection); 2045 break; 2046 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2047 if (!sm_cmac_ready()) break; 2048 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2049 sm_sc_calculate_f6_for_dhkey_check(connection); 2050 break; 2051 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2052 if (!sm_cmac_ready()) break; 2053 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2054 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2055 break; 2056 case SM_SC_W2_CALCULATE_F5_SALT: 2057 if (!sm_cmac_ready()) break; 2058 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2059 f5_calculate_salt(connection); 2060 break; 2061 case SM_SC_W2_CALCULATE_F5_MACKEY: 2062 if (!sm_cmac_ready()) break; 2063 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2064 f5_calculate_mackey(connection); 2065 break; 2066 case SM_SC_W2_CALCULATE_F5_LTK: 2067 if (!sm_cmac_ready()) break; 2068 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2069 f5_calculate_ltk(connection); 2070 break; 2071 case SM_SC_W2_CALCULATE_G2: 2072 if (!sm_cmac_ready()) break; 2073 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2074 g2_calculate(connection); 2075 break; 2076 case SM_SC_W2_CALCULATE_H6_ILK: 2077 if (!sm_cmac_ready()) break; 2078 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2079 h6_calculate_ilk(connection); 2080 break; 2081 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2082 if (!sm_cmac_ready()) break; 2083 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2084 h6_calculate_br_edr_link_key(connection); 2085 break; 2086 2087 #endif 2088 // initiator side 2089 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2090 sm_key_t peer_ltk_flipped; 2091 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2092 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2093 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2094 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2095 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2096 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2097 return; 2098 } 2099 2100 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2101 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2102 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2103 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2104 sm_timeout_reset(connection); 2105 break; 2106 2107 // responder side 2108 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2109 connection->sm_engine_state = SM_RESPONDER_IDLE; 2110 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2111 sm_done_for_handle(connection->sm_handle); 2112 return; 2113 2114 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2115 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2116 uint8_t buffer[65]; 2117 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2118 // 2119 reverse_256(ec_qx, &buffer[1]); 2120 reverse_256(ec_qy, &buffer[33]); 2121 2122 // stk generation method 2123 // passkey entry: notify app to show passkey or to request passkey 2124 switch (setup->sm_stk_generation_method){ 2125 case JUST_WORKS: 2126 case NK_BOTH_INPUT: 2127 if (connection->sm_role){ 2128 // responder 2129 sm_sc_start_calculating_local_confirm(connection); 2130 } else { 2131 // initiator 2132 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2133 } 2134 break; 2135 case PK_INIT_INPUT: 2136 case PK_RESP_INPUT: 2137 case OK_BOTH_INPUT: 2138 // use random TK for display 2139 memcpy(setup->sm_ra, setup->sm_tk, 16); 2140 memcpy(setup->sm_rb, setup->sm_tk, 16); 2141 setup->sm_passkey_bit = 0; 2142 2143 if (connection->sm_role){ 2144 // responder 2145 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2146 } else { 2147 // initiator 2148 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2149 } 2150 sm_trigger_user_response(connection); 2151 break; 2152 case OOB: 2153 // TODO: implement SC OOB 2154 break; 2155 } 2156 2157 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2158 sm_timeout_reset(connection); 2159 break; 2160 } 2161 case SM_SC_SEND_CONFIRMATION: { 2162 uint8_t buffer[17]; 2163 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2164 reverse_128(setup->sm_local_confirm, &buffer[1]); 2165 if (connection->sm_role){ 2166 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2167 } else { 2168 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2169 } 2170 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2171 sm_timeout_reset(connection); 2172 break; 2173 } 2174 case SM_SC_SEND_PAIRING_RANDOM: { 2175 uint8_t buffer[17]; 2176 buffer[0] = SM_CODE_PAIRING_RANDOM; 2177 reverse_128(setup->sm_local_nonce, &buffer[1]); 2178 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2179 if (connection->sm_role){ 2180 // responder 2181 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2182 } else { 2183 // initiator 2184 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2185 } 2186 } else { 2187 if (connection->sm_role){ 2188 // responder 2189 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2190 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2191 } else { 2192 sm_sc_prepare_dhkey_check(connection); 2193 } 2194 } else { 2195 // initiator 2196 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2197 } 2198 } 2199 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2200 sm_timeout_reset(connection); 2201 break; 2202 } 2203 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2204 uint8_t buffer[17]; 2205 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2206 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2207 2208 if (connection->sm_role){ 2209 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2210 } else { 2211 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2212 } 2213 2214 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2215 sm_timeout_reset(connection); 2216 break; 2217 } 2218 2219 #endif 2220 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2221 // echo initiator for now 2222 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2223 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2224 2225 if (setup->sm_use_secure_connections){ 2226 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2227 // skip LTK/EDIV for SC 2228 log_info("sm: dropping encryption information flag"); 2229 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2230 } else { 2231 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2232 } 2233 2234 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); 2235 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); 2236 // update key distribution after ENC was dropped 2237 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2238 2239 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2240 sm_timeout_reset(connection); 2241 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2242 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2243 sm_trigger_user_response(connection); 2244 } 2245 return; 2246 2247 case SM_PH2_SEND_PAIRING_RANDOM: { 2248 uint8_t buffer[17]; 2249 buffer[0] = SM_CODE_PAIRING_RANDOM; 2250 reverse_128(setup->sm_local_random, &buffer[1]); 2251 if (connection->sm_role){ 2252 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2253 } else { 2254 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2255 } 2256 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2257 sm_timeout_reset(connection); 2258 break; 2259 } 2260 2261 case SM_PH2_GET_RANDOM_TK: 2262 case SM_PH2_C1_GET_RANDOM_A: 2263 case SM_PH2_C1_GET_RANDOM_B: 2264 case SM_PH3_GET_RANDOM: 2265 case SM_PH3_GET_DIV: 2266 sm_next_responding_state(connection); 2267 sm_random_start(connection); 2268 return; 2269 2270 case SM_PH2_C1_GET_ENC_B: 2271 case SM_PH2_C1_GET_ENC_D: 2272 // already busy? 2273 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2274 sm_next_responding_state(connection); 2275 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2276 return; 2277 2278 case SM_PH3_LTK_GET_ENC: 2279 case SM_RESPONDER_PH4_LTK_GET_ENC: 2280 // already busy? 2281 if (sm_aes128_state == SM_AES128_IDLE) { 2282 sm_key_t d_prime; 2283 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2284 sm_next_responding_state(connection); 2285 sm_aes128_start(sm_persistent_er, d_prime, connection); 2286 return; 2287 } 2288 break; 2289 2290 case SM_PH3_CSRK_GET_ENC: 2291 // already busy? 2292 if (sm_aes128_state == SM_AES128_IDLE) { 2293 sm_key_t d_prime; 2294 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2295 sm_next_responding_state(connection); 2296 sm_aes128_start(sm_persistent_er, d_prime, connection); 2297 return; 2298 } 2299 break; 2300 2301 case SM_PH2_C1_GET_ENC_C: 2302 // already busy? 2303 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2304 // calculate m_confirm using aes128 engine - step 1 2305 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); 2306 sm_next_responding_state(connection); 2307 sm_aes128_start(setup->sm_tk, plaintext, connection); 2308 break; 2309 case SM_PH2_C1_GET_ENC_A: 2310 // already busy? 2311 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2312 // calculate confirm using aes128 engine - step 1 2313 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); 2314 sm_next_responding_state(connection); 2315 sm_aes128_start(setup->sm_tk, plaintext, connection); 2316 break; 2317 case SM_PH2_CALC_STK: 2318 // already busy? 2319 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2320 // calculate STK 2321 if (connection->sm_role){ 2322 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2323 } else { 2324 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2325 } 2326 sm_next_responding_state(connection); 2327 sm_aes128_start(setup->sm_tk, plaintext, connection); 2328 break; 2329 case SM_PH3_Y_GET_ENC: 2330 // already busy? 2331 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2332 // PH3B2 - calculate Y from - enc 2333 // Y = dm(DHK, Rand) 2334 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2335 sm_next_responding_state(connection); 2336 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2337 return; 2338 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2339 uint8_t buffer[17]; 2340 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2341 reverse_128(setup->sm_local_confirm, &buffer[1]); 2342 if (connection->sm_role){ 2343 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2344 } else { 2345 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2346 } 2347 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2348 sm_timeout_reset(connection); 2349 return; 2350 } 2351 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2352 sm_key_t stk_flipped; 2353 reverse_128(setup->sm_ltk, stk_flipped); 2354 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2355 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2356 return; 2357 } 2358 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2359 sm_key_t stk_flipped; 2360 reverse_128(setup->sm_ltk, stk_flipped); 2361 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2362 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2363 return; 2364 } 2365 case SM_RESPONDER_PH4_SEND_LTK: { 2366 sm_key_t ltk_flipped; 2367 reverse_128(setup->sm_ltk, ltk_flipped); 2368 connection->sm_engine_state = SM_RESPONDER_IDLE; 2369 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2370 return; 2371 } 2372 case SM_RESPONDER_PH4_Y_GET_ENC: 2373 // already busy? 2374 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2375 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2376 // Y = dm(DHK, Rand) 2377 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2378 sm_next_responding_state(connection); 2379 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2380 return; 2381 2382 case SM_PH3_DISTRIBUTE_KEYS: 2383 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2384 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2385 uint8_t buffer[17]; 2386 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2387 reverse_128(setup->sm_ltk, &buffer[1]); 2388 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2389 sm_timeout_reset(connection); 2390 return; 2391 } 2392 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2393 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2394 uint8_t buffer[11]; 2395 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2396 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2397 reverse_64(setup->sm_local_rand, &buffer[3]); 2398 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2399 sm_timeout_reset(connection); 2400 return; 2401 } 2402 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2403 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2404 uint8_t buffer[17]; 2405 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2406 reverse_128(sm_persistent_irk, &buffer[1]); 2407 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2408 sm_timeout_reset(connection); 2409 return; 2410 } 2411 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2412 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2413 bd_addr_t local_address; 2414 uint8_t buffer[8]; 2415 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2416 gap_advertisements_get_address(&buffer[1], local_address); 2417 reverse_bd_addr(local_address, &buffer[2]); 2418 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2419 sm_timeout_reset(connection); 2420 return; 2421 } 2422 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2423 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2424 2425 // hack to reproduce test runs 2426 if (test_use_fixed_local_csrk){ 2427 memset(setup->sm_local_csrk, 0xcc, 16); 2428 } 2429 2430 uint8_t buffer[17]; 2431 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2432 reverse_128(setup->sm_local_csrk, &buffer[1]); 2433 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2434 sm_timeout_reset(connection); 2435 return; 2436 } 2437 2438 // keys are sent 2439 if (connection->sm_role){ 2440 // slave -> receive master keys if any 2441 if (sm_key_distribution_all_received(connection)){ 2442 sm_key_distribution_handle_all_received(connection); 2443 connection->sm_engine_state = SM_RESPONDER_IDLE; 2444 sm_done_for_handle(connection->sm_handle); 2445 } else { 2446 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2447 } 2448 } else { 2449 // master -> all done 2450 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2451 sm_done_for_handle(connection->sm_handle); 2452 } 2453 break; 2454 2455 default: 2456 break; 2457 } 2458 2459 // check again if active connection was released 2460 if (sm_active_connection) break; 2461 } 2462 } 2463 2464 // note: aes engine is ready as we just got the aes result 2465 static void sm_handle_encryption_result(uint8_t * data){ 2466 2467 sm_aes128_state = SM_AES128_IDLE; 2468 2469 if (sm_address_resolution_ah_calculation_active){ 2470 sm_address_resolution_ah_calculation_active = 0; 2471 // compare calulated address against connecting device 2472 uint8_t hash[3]; 2473 reverse_24(data, hash); 2474 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2475 log_info("LE Device Lookup: matched resolvable private address"); 2476 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2477 return; 2478 } 2479 // no match, try next 2480 sm_address_resolution_test++; 2481 return; 2482 } 2483 2484 switch (dkg_state){ 2485 case DKG_W4_IRK: 2486 reverse_128(data, sm_persistent_irk); 2487 log_info_key("irk", sm_persistent_irk); 2488 dkg_next_state(); 2489 return; 2490 case DKG_W4_DHK: 2491 reverse_128(data, sm_persistent_dhk); 2492 log_info_key("dhk", sm_persistent_dhk); 2493 dkg_next_state(); 2494 // SM Init Finished 2495 return; 2496 default: 2497 break; 2498 } 2499 2500 switch (rau_state){ 2501 case RAU_W4_ENC: 2502 reverse_24(data, &sm_random_address[3]); 2503 rau_next_state(); 2504 return; 2505 default: 2506 break; 2507 } 2508 2509 switch (sm_cmac_state){ 2510 case CMAC_W4_SUBKEYS: 2511 case CMAC_W4_MI: 2512 case CMAC_W4_MLAST: 2513 { 2514 sm_key_t t; 2515 reverse_128(data, t); 2516 sm_cmac_handle_encryption_result(t); 2517 } 2518 return; 2519 default: 2520 break; 2521 } 2522 2523 // retrieve sm_connection provided to sm_aes128_start_encryption 2524 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2525 if (!connection) return; 2526 switch (connection->sm_engine_state){ 2527 case SM_PH2_C1_W4_ENC_A: 2528 case SM_PH2_C1_W4_ENC_C: 2529 { 2530 sm_key_t t2; 2531 reverse_128(data, t2); 2532 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2533 } 2534 sm_next_responding_state(connection); 2535 return; 2536 case SM_PH2_C1_W4_ENC_B: 2537 reverse_128(data, setup->sm_local_confirm); 2538 log_info_key("c1!", setup->sm_local_confirm); 2539 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2540 return; 2541 case SM_PH2_C1_W4_ENC_D: 2542 { 2543 sm_key_t peer_confirm_test; 2544 reverse_128(data, peer_confirm_test); 2545 log_info_key("c1!", peer_confirm_test); 2546 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2547 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2548 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2549 return; 2550 } 2551 if (connection->sm_role){ 2552 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2553 } else { 2554 connection->sm_engine_state = SM_PH2_CALC_STK; 2555 } 2556 } 2557 return; 2558 case SM_PH2_W4_STK: 2559 reverse_128(data, setup->sm_ltk); 2560 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2561 log_info_key("stk", setup->sm_ltk); 2562 if (connection->sm_role){ 2563 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2564 } else { 2565 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2566 } 2567 return; 2568 case SM_PH3_Y_W4_ENC:{ 2569 sm_key_t y128; 2570 reverse_128(data, y128); 2571 setup->sm_local_y = big_endian_read_16(y128, 14); 2572 log_info_hex16("y", setup->sm_local_y); 2573 // PH3B3 - calculate EDIV 2574 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2575 log_info_hex16("ediv", setup->sm_local_ediv); 2576 // PH3B4 - calculate LTK - enc 2577 // LTK = d1(ER, DIV, 0)) 2578 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2579 return; 2580 } 2581 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2582 sm_key_t y128; 2583 reverse_128(data, y128); 2584 setup->sm_local_y = big_endian_read_16(y128, 14); 2585 log_info_hex16("y", setup->sm_local_y); 2586 2587 // PH3B3 - calculate DIV 2588 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2589 log_info_hex16("ediv", setup->sm_local_ediv); 2590 // PH3B4 - calculate LTK - enc 2591 // LTK = d1(ER, DIV, 0)) 2592 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2593 return; 2594 } 2595 case SM_PH3_LTK_W4_ENC: 2596 reverse_128(data, setup->sm_ltk); 2597 log_info_key("ltk", setup->sm_ltk); 2598 // calc CSRK next 2599 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2600 return; 2601 case SM_PH3_CSRK_W4_ENC: 2602 reverse_128(data, setup->sm_local_csrk); 2603 log_info_key("csrk", setup->sm_local_csrk); 2604 if (setup->sm_key_distribution_send_set){ 2605 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2606 } else { 2607 // no keys to send, just continue 2608 if (connection->sm_role){ 2609 // slave -> receive master keys 2610 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2611 } else { 2612 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2613 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2614 } else { 2615 // master -> all done 2616 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2617 sm_done_for_handle(connection->sm_handle); 2618 } 2619 } 2620 } 2621 return; 2622 case SM_RESPONDER_PH4_LTK_W4_ENC: 2623 reverse_128(data, setup->sm_ltk); 2624 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2625 log_info_key("ltk", setup->sm_ltk); 2626 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2627 return; 2628 default: 2629 break; 2630 } 2631 } 2632 2633 #ifdef USE_MBEDTLS_FOR_ECDH 2634 2635 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2636 int offset = setup->sm_passkey_bit; 2637 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2638 while (size) { 2639 if (offset < 32){ 2640 *buffer++ = setup->sm_peer_qx[offset++]; 2641 } else { 2642 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2643 } 2644 size--; 2645 } 2646 setup->sm_passkey_bit = offset; 2647 return 0; 2648 } 2649 #endif 2650 2651 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2652 static void sm_handle_random_result(uint8_t * data){ 2653 2654 #ifdef USE_MBEDTLS_FOR_ECDH 2655 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2656 int num_bytes = setup->sm_passkey_bit; 2657 if (num_bytes < 32){ 2658 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2659 } else { 2660 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2661 } 2662 num_bytes += 8; 2663 setup->sm_passkey_bit = num_bytes; 2664 2665 if (num_bytes >= 64){ 2666 // generate EC key 2667 setup->sm_passkey_bit = 0; 2668 mbedtls_mpi d; 2669 mbedtls_ecp_point P; 2670 mbedtls_mpi_init(&d); 2671 mbedtls_ecp_point_init(&P); 2672 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2673 log_info("gen keypair %x", res); 2674 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2675 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2676 mbedtls_mpi_write_binary(&d, ec_d, 32); 2677 mbedtls_ecp_point_free(&P); 2678 mbedtls_mpi_free(&d); 2679 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2680 sm_log_ec_keypair(); 2681 2682 #if 0 2683 printf("test dhkey check\n"); 2684 sm_key256_t dhkey; 2685 memcpy(setup->sm_peer_qx, ec_qx, 32); 2686 memcpy(setup->sm_peer_qy, ec_qy, 32); 2687 sm_sc_calculate_dhkey(dhkey); 2688 #endif 2689 2690 } 2691 } 2692 #endif 2693 2694 switch (rau_state){ 2695 case RAU_W4_RANDOM: 2696 // non-resolvable vs. resolvable 2697 switch (gap_random_adress_type){ 2698 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2699 // resolvable: use random as prand and calc address hash 2700 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2701 memcpy(sm_random_address, data, 3); 2702 sm_random_address[0] &= 0x3f; 2703 sm_random_address[0] |= 0x40; 2704 rau_state = RAU_GET_ENC; 2705 break; 2706 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2707 default: 2708 // "The two most significant bits of the address shall be equal to ‘0’"" 2709 memcpy(sm_random_address, data, 6); 2710 sm_random_address[0] &= 0x3f; 2711 rau_state = RAU_SET_ADDRESS; 2712 break; 2713 } 2714 return; 2715 default: 2716 break; 2717 } 2718 2719 // retrieve sm_connection provided to sm_random_start 2720 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2721 if (!connection) return; 2722 switch (connection->sm_engine_state){ 2723 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2724 case SM_SC_W4_GET_RANDOM_A: 2725 memcpy(&setup->sm_local_nonce[0], data, 8); 2726 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2727 break; 2728 case SM_SC_W4_GET_RANDOM_B: 2729 memcpy(&setup->sm_local_nonce[8], data, 8); 2730 // initiator & jw/nc -> send pairing random 2731 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2732 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2733 break; 2734 } else { 2735 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2736 } 2737 break; 2738 #endif 2739 2740 case SM_PH2_W4_RANDOM_TK: 2741 { 2742 // map random to 0-999999 without speding much cycles on a modulus operation 2743 uint32_t tk = little_endian_read_32(data,0); 2744 tk = tk & 0xfffff; // 1048575 2745 if (tk >= 999999){ 2746 tk = tk - 999999; 2747 } 2748 sm_reset_tk(); 2749 big_endian_store_32(setup->sm_tk, 12, tk); 2750 if (connection->sm_role){ 2751 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2752 } else { 2753 if (setup->sm_use_secure_connections){ 2754 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2755 } else { 2756 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2757 sm_trigger_user_response(connection); 2758 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2759 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2760 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2761 } 2762 } 2763 } 2764 return; 2765 } 2766 case SM_PH2_C1_W4_RANDOM_A: 2767 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2768 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2769 return; 2770 case SM_PH2_C1_W4_RANDOM_B: 2771 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2772 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2773 return; 2774 case SM_PH3_W4_RANDOM: 2775 reverse_64(data, setup->sm_local_rand); 2776 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2777 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2778 // no db for authenticated flag hack: store flag in bit 4 of LSB 2779 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2780 connection->sm_engine_state = SM_PH3_GET_DIV; 2781 return; 2782 case SM_PH3_W4_DIV: 2783 // use 16 bit from random value as div 2784 setup->sm_local_div = big_endian_read_16(data, 0); 2785 log_info_hex16("div", setup->sm_local_div); 2786 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2787 return; 2788 default: 2789 break; 2790 } 2791 } 2792 2793 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2794 2795 sm_connection_t * sm_conn; 2796 hci_con_handle_t con_handle; 2797 2798 switch (packet_type) { 2799 2800 case HCI_EVENT_PACKET: 2801 switch (hci_event_packet_get_type(packet)) { 2802 2803 case BTSTACK_EVENT_STATE: 2804 // bt stack activated, get started 2805 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2806 log_info("HCI Working!"); 2807 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2808 rau_state = RAU_IDLE; 2809 #ifdef USE_MBEDTLS_FOR_ECDH 2810 if (!sm_have_ec_keypair){ 2811 setup->sm_passkey_bit = 0; 2812 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2813 } 2814 #endif 2815 sm_run(); 2816 } 2817 break; 2818 2819 case HCI_EVENT_LE_META: 2820 switch (packet[2]) { 2821 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2822 2823 log_info("sm: connected"); 2824 2825 if (packet[3]) return; // connection failed 2826 2827 con_handle = little_endian_read_16(packet, 4); 2828 sm_conn = sm_get_connection_for_handle(con_handle); 2829 if (!sm_conn) break; 2830 2831 sm_conn->sm_handle = con_handle; 2832 sm_conn->sm_role = packet[6]; 2833 sm_conn->sm_peer_addr_type = packet[7]; 2834 reverse_bd_addr(&packet[8], 2835 sm_conn->sm_peer_address); 2836 2837 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2838 2839 // reset security properties 2840 sm_conn->sm_connection_encrypted = 0; 2841 sm_conn->sm_connection_authenticated = 0; 2842 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2843 sm_conn->sm_le_db_index = -1; 2844 2845 // prepare CSRK lookup (does not involve setup) 2846 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2847 2848 // just connected -> everything else happens in sm_run() 2849 if (sm_conn->sm_role){ 2850 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2851 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2852 if (sm_slave_request_security) { 2853 // request security if requested by app 2854 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2855 } else { 2856 // otherwise, wait for pairing request 2857 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2858 } 2859 } 2860 break; 2861 } else { 2862 // master 2863 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2864 } 2865 break; 2866 2867 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2868 con_handle = little_endian_read_16(packet, 3); 2869 sm_conn = sm_get_connection_for_handle(con_handle); 2870 if (!sm_conn) break; 2871 2872 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2873 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2874 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2875 break; 2876 } 2877 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2878 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2879 break; 2880 } 2881 2882 // store rand and ediv 2883 reverse_64(&packet[5], sm_conn->sm_local_rand); 2884 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2885 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2886 break; 2887 2888 default: 2889 break; 2890 } 2891 break; 2892 2893 case HCI_EVENT_ENCRYPTION_CHANGE: 2894 con_handle = little_endian_read_16(packet, 3); 2895 sm_conn = sm_get_connection_for_handle(con_handle); 2896 if (!sm_conn) break; 2897 2898 sm_conn->sm_connection_encrypted = packet[5]; 2899 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2900 sm_conn->sm_actual_encryption_key_size); 2901 log_info("event handler, state %u", sm_conn->sm_engine_state); 2902 if (!sm_conn->sm_connection_encrypted) break; 2903 // continue if part of initial pairing 2904 switch (sm_conn->sm_engine_state){ 2905 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2906 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2907 sm_done_for_handle(sm_conn->sm_handle); 2908 break; 2909 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2910 if (sm_conn->sm_role){ 2911 // slave 2912 if (setup->sm_use_secure_connections){ 2913 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2914 } else { 2915 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2916 } 2917 } else { 2918 // master 2919 if (sm_key_distribution_all_received(sm_conn)){ 2920 // skip receiving keys as there are none 2921 sm_key_distribution_handle_all_received(sm_conn); 2922 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2923 } else { 2924 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2925 } 2926 } 2927 break; 2928 default: 2929 break; 2930 } 2931 break; 2932 2933 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2934 con_handle = little_endian_read_16(packet, 3); 2935 sm_conn = sm_get_connection_for_handle(con_handle); 2936 if (!sm_conn) break; 2937 2938 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2939 log_info("event handler, state %u", sm_conn->sm_engine_state); 2940 // continue if part of initial pairing 2941 switch (sm_conn->sm_engine_state){ 2942 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2943 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2944 sm_done_for_handle(sm_conn->sm_handle); 2945 break; 2946 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2947 if (sm_conn->sm_role){ 2948 // slave 2949 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2950 } else { 2951 // master 2952 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2953 } 2954 break; 2955 default: 2956 break; 2957 } 2958 break; 2959 2960 2961 case HCI_EVENT_DISCONNECTION_COMPLETE: 2962 con_handle = little_endian_read_16(packet, 3); 2963 sm_done_for_handle(con_handle); 2964 sm_conn = sm_get_connection_for_handle(con_handle); 2965 if (!sm_conn) break; 2966 2967 // delete stored bonding on disconnect with authentication failure in ph0 2968 if (sm_conn->sm_role == 0 2969 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2970 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2971 le_device_db_remove(sm_conn->sm_le_db_index); 2972 } 2973 2974 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2975 sm_conn->sm_handle = 0; 2976 break; 2977 2978 case HCI_EVENT_COMMAND_COMPLETE: 2979 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2980 sm_handle_encryption_result(&packet[6]); 2981 break; 2982 } 2983 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2984 sm_handle_random_result(&packet[6]); 2985 break; 2986 } 2987 break; 2988 default: 2989 break; 2990 } 2991 break; 2992 default: 2993 break; 2994 } 2995 2996 sm_run(); 2997 } 2998 2999 static inline int sm_calc_actual_encryption_key_size(int other){ 3000 if (other < sm_min_encryption_key_size) return 0; 3001 if (other < sm_max_encryption_key_size) return other; 3002 return sm_max_encryption_key_size; 3003 } 3004 3005 3006 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3007 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3008 switch (method){ 3009 case JUST_WORKS: 3010 case NK_BOTH_INPUT: 3011 return 1; 3012 default: 3013 return 0; 3014 } 3015 } 3016 // responder 3017 3018 static int sm_passkey_used(stk_generation_method_t method){ 3019 switch (method){ 3020 case PK_RESP_INPUT: 3021 return 1; 3022 default: 3023 return 0; 3024 } 3025 } 3026 #endif 3027 3028 /** 3029 * @return ok 3030 */ 3031 static int sm_validate_stk_generation_method(void){ 3032 // check if STK generation method is acceptable by client 3033 switch (setup->sm_stk_generation_method){ 3034 case JUST_WORKS: 3035 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3036 case PK_RESP_INPUT: 3037 case PK_INIT_INPUT: 3038 case OK_BOTH_INPUT: 3039 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3040 case OOB: 3041 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3042 case NK_BOTH_INPUT: 3043 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3044 return 1; 3045 default: 3046 return 0; 3047 } 3048 } 3049 3050 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3051 3052 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3053 sm_run(); 3054 } 3055 3056 if (packet_type != SM_DATA_PACKET) return; 3057 3058 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3059 if (!sm_conn) return; 3060 3061 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3062 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3063 return; 3064 } 3065 3066 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3067 3068 int err; 3069 3070 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3071 uint8_t buffer[5]; 3072 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3073 buffer[1] = 3; 3074 little_endian_store_16(buffer, 2, con_handle); 3075 buffer[4] = packet[1]; 3076 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3077 return; 3078 } 3079 3080 switch (sm_conn->sm_engine_state){ 3081 3082 // a sm timeout requries a new physical connection 3083 case SM_GENERAL_TIMEOUT: 3084 return; 3085 3086 // Initiator 3087 case SM_INITIATOR_CONNECTED: 3088 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3089 sm_pdu_received_in_wrong_state(sm_conn); 3090 break; 3091 } 3092 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3093 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3094 break; 3095 } 3096 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3097 sm_key_t ltk; 3098 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3099 if (!sm_is_null_key(ltk)){ 3100 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3101 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3102 } else { 3103 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3104 } 3105 break; 3106 } 3107 // otherwise, store security request 3108 sm_conn->sm_security_request_received = 1; 3109 break; 3110 3111 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3112 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3113 sm_pdu_received_in_wrong_state(sm_conn); 3114 break; 3115 } 3116 // store pairing request 3117 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3118 err = sm_stk_generation_init(sm_conn); 3119 if (err){ 3120 setup->sm_pairing_failed_reason = err; 3121 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3122 break; 3123 } 3124 3125 // generate random number first, if we need to show passkey 3126 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3127 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3128 break; 3129 } 3130 3131 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3132 if (setup->sm_use_secure_connections){ 3133 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3134 if (setup->sm_stk_generation_method == JUST_WORKS){ 3135 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3136 sm_trigger_user_response(sm_conn); 3137 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3138 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3139 } 3140 } else { 3141 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3142 } 3143 break; 3144 } 3145 #endif 3146 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3147 sm_trigger_user_response(sm_conn); 3148 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3149 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3150 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3151 } 3152 break; 3153 3154 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3155 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3156 sm_pdu_received_in_wrong_state(sm_conn); 3157 break; 3158 } 3159 3160 // store s_confirm 3161 reverse_128(&packet[1], setup->sm_peer_confirm); 3162 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3163 break; 3164 3165 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3166 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3167 sm_pdu_received_in_wrong_state(sm_conn); 3168 break;; 3169 } 3170 3171 // received random value 3172 reverse_128(&packet[1], setup->sm_peer_random); 3173 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3174 break; 3175 3176 // Responder 3177 case SM_RESPONDER_IDLE: 3178 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3179 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3180 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3181 sm_pdu_received_in_wrong_state(sm_conn); 3182 break;; 3183 } 3184 3185 // store pairing request 3186 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3187 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3188 break; 3189 3190 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3191 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3192 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3193 sm_pdu_received_in_wrong_state(sm_conn); 3194 break; 3195 } 3196 3197 // store public key for DH Key calculation 3198 reverse_256(&packet[01], setup->sm_peer_qx); 3199 reverse_256(&packet[33], setup->sm_peer_qy); 3200 3201 #ifdef USE_MBEDTLS_FOR_ECDH 3202 // validate public key 3203 mbedtls_ecp_point Q; 3204 mbedtls_ecp_point_init( &Q ); 3205 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3206 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3207 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3208 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3209 mbedtls_ecp_point_free( & Q); 3210 if (err){ 3211 log_error("sm: peer public key invalid %x", err); 3212 // uses "unspecified reason", there is no "public key invalid" error code 3213 sm_pdu_received_in_wrong_state(sm_conn); 3214 break; 3215 } 3216 3217 #endif 3218 if (sm_conn->sm_role){ 3219 // responder 3220 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3221 } else { 3222 // initiator 3223 // stk generation method 3224 // passkey entry: notify app to show passkey or to request passkey 3225 switch (setup->sm_stk_generation_method){ 3226 case JUST_WORKS: 3227 case NK_BOTH_INPUT: 3228 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3229 break; 3230 case PK_RESP_INPUT: 3231 sm_sc_start_calculating_local_confirm(sm_conn); 3232 break; 3233 case PK_INIT_INPUT: 3234 case OK_BOTH_INPUT: 3235 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3236 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3237 break; 3238 } 3239 sm_sc_start_calculating_local_confirm(sm_conn); 3240 break; 3241 case OOB: 3242 // TODO: implement SC OOB 3243 break; 3244 } 3245 } 3246 break; 3247 3248 case SM_SC_W4_CONFIRMATION: 3249 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3250 sm_pdu_received_in_wrong_state(sm_conn); 3251 break; 3252 } 3253 // received confirm value 3254 reverse_128(&packet[1], setup->sm_peer_confirm); 3255 3256 if (sm_conn->sm_role){ 3257 // responder 3258 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3259 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3260 // still waiting for passkey 3261 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3262 break; 3263 } 3264 } 3265 sm_sc_start_calculating_local_confirm(sm_conn); 3266 } else { 3267 // initiator 3268 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3269 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3270 } else { 3271 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3272 } 3273 } 3274 break; 3275 3276 case SM_SC_W4_PAIRING_RANDOM: 3277 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3278 sm_pdu_received_in_wrong_state(sm_conn); 3279 break; 3280 } 3281 3282 // received random value 3283 reverse_128(&packet[1], setup->sm_peer_nonce); 3284 3285 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3286 // only check for JUST WORK/NC in initiator role AND passkey entry 3287 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3288 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3289 } 3290 3291 sm_sc_state_after_receiving_random(sm_conn); 3292 break; 3293 3294 case SM_SC_W2_CALCULATE_G2: 3295 case SM_SC_W4_CALCULATE_G2: 3296 case SM_SC_W2_CALCULATE_F5_SALT: 3297 case SM_SC_W4_CALCULATE_F5_SALT: 3298 case SM_SC_W2_CALCULATE_F5_MACKEY: 3299 case SM_SC_W4_CALCULATE_F5_MACKEY: 3300 case SM_SC_W2_CALCULATE_F5_LTK: 3301 case SM_SC_W4_CALCULATE_F5_LTK: 3302 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3303 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3304 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3305 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3306 sm_pdu_received_in_wrong_state(sm_conn); 3307 break; 3308 } 3309 // store DHKey Check 3310 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3311 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3312 3313 // have we been only waiting for dhkey check command? 3314 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3315 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3316 } 3317 break; 3318 #endif 3319 3320 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3321 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3322 sm_pdu_received_in_wrong_state(sm_conn); 3323 break; 3324 } 3325 3326 // received confirm value 3327 reverse_128(&packet[1], setup->sm_peer_confirm); 3328 3329 // notify client to hide shown passkey 3330 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3331 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3332 } 3333 3334 // handle user cancel pairing? 3335 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3336 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3337 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3338 break; 3339 } 3340 3341 // wait for user action? 3342 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3343 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3344 break; 3345 } 3346 3347 // calculate and send local_confirm 3348 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3349 break; 3350 3351 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3352 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3353 sm_pdu_received_in_wrong_state(sm_conn); 3354 break;; 3355 } 3356 3357 // received random value 3358 reverse_128(&packet[1], setup->sm_peer_random); 3359 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3360 break; 3361 3362 case SM_PH3_RECEIVE_KEYS: 3363 switch(packet[0]){ 3364 case SM_CODE_ENCRYPTION_INFORMATION: 3365 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3366 reverse_128(&packet[1], setup->sm_peer_ltk); 3367 break; 3368 3369 case SM_CODE_MASTER_IDENTIFICATION: 3370 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3371 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3372 reverse_64(&packet[3], setup->sm_peer_rand); 3373 break; 3374 3375 case SM_CODE_IDENTITY_INFORMATION: 3376 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3377 reverse_128(&packet[1], setup->sm_peer_irk); 3378 break; 3379 3380 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3381 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3382 setup->sm_peer_addr_type = packet[1]; 3383 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3384 break; 3385 3386 case SM_CODE_SIGNING_INFORMATION: 3387 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3388 reverse_128(&packet[1], setup->sm_peer_csrk); 3389 break; 3390 default: 3391 // Unexpected PDU 3392 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3393 break; 3394 } 3395 // done with key distribution? 3396 if (sm_key_distribution_all_received(sm_conn)){ 3397 3398 sm_key_distribution_handle_all_received(sm_conn); 3399 3400 if (sm_conn->sm_role){ 3401 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3402 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3403 } else { 3404 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3405 sm_done_for_handle(sm_conn->sm_handle); 3406 } 3407 } else { 3408 if (setup->sm_use_secure_connections){ 3409 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3410 } else { 3411 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3412 } 3413 } 3414 } 3415 break; 3416 default: 3417 // Unexpected PDU 3418 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3419 break; 3420 } 3421 3422 // try to send preparared packet 3423 sm_run(); 3424 } 3425 3426 // Security Manager Client API 3427 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3428 sm_get_oob_data = get_oob_data_callback; 3429 } 3430 3431 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3432 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3433 } 3434 3435 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3436 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3437 } 3438 3439 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3440 sm_min_encryption_key_size = min_size; 3441 sm_max_encryption_key_size = max_size; 3442 } 3443 3444 void sm_set_authentication_requirements(uint8_t auth_req){ 3445 sm_auth_req = auth_req; 3446 } 3447 3448 void sm_set_io_capabilities(io_capability_t io_capability){ 3449 sm_io_capabilities = io_capability; 3450 } 3451 3452 void sm_set_request_security(int enable){ 3453 sm_slave_request_security = enable; 3454 } 3455 3456 void sm_set_er(sm_key_t er){ 3457 memcpy(sm_persistent_er, er, 16); 3458 } 3459 3460 void sm_set_ir(sm_key_t ir){ 3461 memcpy(sm_persistent_ir, ir, 16); 3462 } 3463 3464 // Testing support only 3465 void sm_test_set_irk(sm_key_t irk){ 3466 memcpy(sm_persistent_irk, irk, 16); 3467 sm_persistent_irk_ready = 1; 3468 } 3469 3470 void sm_test_use_fixed_local_csrk(void){ 3471 test_use_fixed_local_csrk = 1; 3472 } 3473 3474 void sm_init(void){ 3475 // set some (BTstack default) ER and IR 3476 int i; 3477 sm_key_t er; 3478 sm_key_t ir; 3479 for (i=0;i<16;i++){ 3480 er[i] = 0x30 + i; 3481 ir[i] = 0x90 + i; 3482 } 3483 sm_set_er(er); 3484 sm_set_ir(ir); 3485 // defaults 3486 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3487 | SM_STK_GENERATION_METHOD_OOB 3488 | SM_STK_GENERATION_METHOD_PASSKEY 3489 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3490 3491 sm_max_encryption_key_size = 16; 3492 sm_min_encryption_key_size = 7; 3493 3494 sm_cmac_state = CMAC_IDLE; 3495 dkg_state = DKG_W4_WORKING; 3496 rau_state = RAU_W4_WORKING; 3497 sm_aes128_state = SM_AES128_IDLE; 3498 sm_address_resolution_test = -1; // no private address to resolve yet 3499 sm_address_resolution_ah_calculation_active = 0; 3500 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3501 sm_address_resolution_general_queue = NULL; 3502 3503 gap_random_adress_update_period = 15 * 60 * 1000L; 3504 3505 sm_active_connection = 0; 3506 3507 test_use_fixed_local_csrk = 0; 3508 3509 // register for HCI Events from HCI 3510 hci_event_callback_registration.callback = &sm_event_packet_handler; 3511 hci_add_event_handler(&hci_event_callback_registration); 3512 3513 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3514 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3515 3516 #ifdef USE_MBEDTLS_FOR_ECDH 3517 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3518 3519 #ifndef HAVE_MALLOC 3520 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3521 #endif 3522 mbedtls_ecp_group_init(&mbedtls_ec_group); 3523 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3524 3525 #if 0 3526 // test 3527 sm_test_use_fixed_ec_keypair(); 3528 if (sm_have_ec_keypair){ 3529 printf("test dhkey check\n"); 3530 sm_key256_t dhkey; 3531 memcpy(setup->sm_peer_qx, ec_qx, 32); 3532 memcpy(setup->sm_peer_qy, ec_qy, 32); 3533 sm_sc_calculate_dhkey(dhkey); 3534 } 3535 #endif 3536 #endif 3537 } 3538 3539 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3540 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3541 memcpy(ec_qx, qx, 32); 3542 memcpy(ec_qy, qy, 32); 3543 memcpy(ec_d, d, 32); 3544 sm_have_ec_keypair = 1; 3545 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3546 #endif 3547 } 3548 3549 void sm_test_use_fixed_ec_keypair(void){ 3550 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3551 #ifdef USE_MBEDTLS_FOR_ECDH 3552 // use test keypair from spec 3553 mbedtls_mpi x; 3554 mbedtls_mpi_init(&x); 3555 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3556 mbedtls_mpi_write_binary(&x, ec_d, 32); 3557 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3558 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3559 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3560 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3561 mbedtls_mpi_free(&x); 3562 #endif 3563 sm_have_ec_keypair = 1; 3564 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3565 #endif 3566 } 3567 3568 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3569 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3570 if (!hci_con) return NULL; 3571 return &hci_con->sm_connection; 3572 } 3573 3574 // @returns 0 if not encrypted, 7-16 otherwise 3575 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3576 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3577 if (!sm_conn) return 0; // wrong connection 3578 if (!sm_conn->sm_connection_encrypted) return 0; 3579 return sm_conn->sm_actual_encryption_key_size; 3580 } 3581 3582 int sm_authenticated(hci_con_handle_t con_handle){ 3583 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3584 if (!sm_conn) return 0; // wrong connection 3585 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3586 return sm_conn->sm_connection_authenticated; 3587 } 3588 3589 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3590 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3591 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3592 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3593 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3594 return sm_conn->sm_connection_authorization_state; 3595 } 3596 3597 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3598 switch (sm_conn->sm_engine_state){ 3599 case SM_GENERAL_IDLE: 3600 case SM_RESPONDER_IDLE: 3601 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3602 sm_run(); 3603 break; 3604 default: 3605 break; 3606 } 3607 } 3608 3609 /** 3610 * @brief Trigger Security Request 3611 */ 3612 void sm_send_security_request(hci_con_handle_t con_handle){ 3613 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3614 if (!sm_conn) return; 3615 sm_send_security_request_for_connection(sm_conn); 3616 } 3617 3618 // request pairing 3619 void sm_request_pairing(hci_con_handle_t con_handle){ 3620 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3621 if (!sm_conn) return; // wrong connection 3622 3623 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3624 if (sm_conn->sm_role){ 3625 sm_send_security_request_for_connection(sm_conn); 3626 } else { 3627 // used as a trigger to start central/master/initiator security procedures 3628 uint16_t ediv; 3629 sm_key_t ltk; 3630 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3631 switch (sm_conn->sm_irk_lookup_state){ 3632 case IRK_LOOKUP_FAILED: 3633 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3634 break; 3635 case IRK_LOOKUP_SUCCEEDED: 3636 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3637 if (!sm_is_null_key(ltk) || ediv){ 3638 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3639 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3640 } else { 3641 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3642 } 3643 break; 3644 default: 3645 sm_conn->sm_bonding_requested = 1; 3646 break; 3647 } 3648 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3649 sm_conn->sm_bonding_requested = 1; 3650 } 3651 } 3652 sm_run(); 3653 } 3654 3655 // called by client app on authorization request 3656 void sm_authorization_decline(hci_con_handle_t con_handle){ 3657 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3658 if (!sm_conn) return; // wrong connection 3659 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3660 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3661 } 3662 3663 void sm_authorization_grant(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 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3667 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3668 } 3669 3670 // GAP Bonding API 3671 3672 void sm_bonding_decline(hci_con_handle_t con_handle){ 3673 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3674 if (!sm_conn) return; // wrong connection 3675 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3676 3677 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3678 switch (setup->sm_stk_generation_method){ 3679 case PK_RESP_INPUT: 3680 case PK_INIT_INPUT: 3681 case OK_BOTH_INPUT: 3682 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3683 break; 3684 case NK_BOTH_INPUT: 3685 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3686 break; 3687 case JUST_WORKS: 3688 case OOB: 3689 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3690 break; 3691 } 3692 } 3693 sm_run(); 3694 } 3695 3696 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3697 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3698 if (!sm_conn) return; // wrong connection 3699 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3700 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3701 if (setup->sm_use_secure_connections){ 3702 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3703 } else { 3704 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3705 } 3706 } 3707 3708 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3709 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3710 sm_sc_prepare_dhkey_check(sm_conn); 3711 } 3712 #endif 3713 3714 sm_run(); 3715 } 3716 3717 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3718 // for now, it's the same 3719 sm_just_works_confirm(con_handle); 3720 } 3721 3722 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3723 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3724 if (!sm_conn) return; // wrong connection 3725 sm_reset_tk(); 3726 big_endian_store_32(setup->sm_tk, 12, passkey); 3727 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3728 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3729 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3730 } 3731 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3732 memcpy(setup->sm_ra, setup->sm_tk, 16); 3733 memcpy(setup->sm_rb, setup->sm_tk, 16); 3734 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3735 sm_sc_start_calculating_local_confirm(sm_conn); 3736 } 3737 #endif 3738 sm_run(); 3739 } 3740 3741 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3742 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3743 if (!sm_conn) return; // wrong connection 3744 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3745 setup->sm_keypress_notification = action; 3746 sm_run(); 3747 } 3748 3749 /** 3750 * @brief Identify device in LE Device DB 3751 * @param handle 3752 * @returns index from le_device_db or -1 if not found/identified 3753 */ 3754 int sm_le_device_index(hci_con_handle_t con_handle ){ 3755 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3756 if (!sm_conn) return -1; 3757 return sm_conn->sm_le_db_index; 3758 } 3759 3760 // GAP LE API 3761 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3762 gap_random_address_update_stop(); 3763 gap_random_adress_type = random_address_type; 3764 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3765 gap_random_address_update_start(); 3766 gap_random_address_trigger(); 3767 } 3768 3769 gap_random_address_type_t gap_random_address_get_mode(void){ 3770 return gap_random_adress_type; 3771 } 3772 3773 void gap_random_address_set_update_period(int period_ms){ 3774 gap_random_adress_update_period = period_ms; 3775 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3776 gap_random_address_update_stop(); 3777 gap_random_address_update_start(); 3778 } 3779 3780 void gap_random_address_set(bd_addr_t addr){ 3781 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3782 memcpy(sm_random_address, addr, 6); 3783 rau_state = RAU_SET_ADDRESS; 3784 sm_run(); 3785 } 3786 3787 /* 3788 * @brief Set Advertisement Paramters 3789 * @param adv_int_min 3790 * @param adv_int_max 3791 * @param adv_type 3792 * @param direct_address_type 3793 * @param direct_address 3794 * @param channel_map 3795 * @param filter_policy 3796 * 3797 * @note own_address_type is used from gap_random_address_set_mode 3798 */ 3799 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3800 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3801 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3802 direct_address_typ, direct_address, channel_map, filter_policy); 3803 } 3804 3805