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