1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 55 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 56 #else 57 #define USE_MBEDTLS_FOR_ECDH 58 #endif 59 #endif 60 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #include "mbedtls/config.h" 65 #include "mbedtls/platform.h" 66 #include "mbedtls/ecp.h" 67 #include "sm_mbedtls_allocator.h" 68 #endif 69 70 // 71 // SM internal types and globals 72 // 73 74 typedef enum { 75 DKG_W4_WORKING, 76 DKG_CALC_IRK, 77 DKG_W4_IRK, 78 DKG_CALC_DHK, 79 DKG_W4_DHK, 80 DKG_READY 81 } derived_key_generation_t; 82 83 typedef enum { 84 RAU_W4_WORKING, 85 RAU_IDLE, 86 RAU_GET_RANDOM, 87 RAU_W4_RANDOM, 88 RAU_GET_ENC, 89 RAU_W4_ENC, 90 RAU_SET_ADDRESS, 91 } random_address_update_t; 92 93 typedef enum { 94 CMAC_IDLE, 95 CMAC_CALC_SUBKEYS, 96 CMAC_W4_SUBKEYS, 97 CMAC_CALC_MI, 98 CMAC_W4_MI, 99 CMAC_CALC_MLAST, 100 CMAC_W4_MLAST 101 } cmac_state_t; 102 103 typedef enum { 104 JUST_WORKS, 105 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 106 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 107 OK_BOTH_INPUT, // Only input on both, both input PK 108 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 109 OOB // OOB available on both sides 110 } stk_generation_method_t; 111 112 typedef enum { 113 SM_USER_RESPONSE_IDLE, 114 SM_USER_RESPONSE_PENDING, 115 SM_USER_RESPONSE_CONFIRM, 116 SM_USER_RESPONSE_PASSKEY, 117 SM_USER_RESPONSE_DECLINE 118 } sm_user_response_t; 119 120 typedef enum { 121 SM_AES128_IDLE, 122 SM_AES128_ACTIVE 123 } sm_aes128_state_t; 124 125 typedef enum { 126 ADDRESS_RESOLUTION_IDLE, 127 ADDRESS_RESOLUTION_GENERAL, 128 ADDRESS_RESOLUTION_FOR_CONNECTION, 129 } address_resolution_mode_t; 130 131 typedef enum { 132 ADDRESS_RESOLUTION_SUCEEDED, 133 ADDRESS_RESOLUTION_FAILED, 134 } address_resolution_event_t; 135 136 typedef enum { 137 EC_KEY_GENERATION_IDLE, 138 EC_KEY_GENERATION_ACTIVE, 139 EC_KEY_GENERATION_DONE, 140 } ec_key_generation_state_t; 141 142 typedef enum { 143 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 144 } sm_state_var_t; 145 146 // 147 // GLOBAL DATA 148 // 149 150 static uint8_t test_use_fixed_local_csrk; 151 152 // configuration 153 static uint8_t sm_accepted_stk_generation_methods; 154 static uint8_t sm_max_encryption_key_size; 155 static uint8_t sm_min_encryption_key_size; 156 static uint8_t sm_auth_req = 0; 157 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 158 static uint8_t sm_slave_request_security; 159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 160 static uint8_t sm_have_ec_keypair; 161 #endif 162 163 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 164 static sm_key_t sm_persistent_er; 165 static sm_key_t sm_persistent_ir; 166 167 // derived from sm_persistent_ir 168 static sm_key_t sm_persistent_dhk; 169 static sm_key_t sm_persistent_irk; 170 static uint8_t sm_persistent_irk_ready = 0; // used for testing 171 static derived_key_generation_t dkg_state; 172 173 // derived from sm_persistent_er 174 // .. 175 176 // random address update 177 static random_address_update_t rau_state; 178 static bd_addr_t sm_random_address; 179 180 // CMAC Calculation: General 181 static cmac_state_t sm_cmac_state; 182 static uint16_t sm_cmac_message_len; 183 static sm_key_t sm_cmac_k; 184 static sm_key_t sm_cmac_x; 185 static sm_key_t sm_cmac_m_last; 186 static uint8_t sm_cmac_block_current; 187 static uint8_t sm_cmac_block_count; 188 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 189 static void (*sm_cmac_done_handler)(uint8_t * hash); 190 191 // CMAC for ATT Signed Writes 192 static uint8_t sm_cmac_header[3]; 193 static const uint8_t * sm_cmac_message; 194 static uint8_t sm_cmac_sign_counter[4]; 195 196 // CMAC for Secure Connection functions 197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 198 static sm_connection_t * sm_cmac_connection; 199 static uint8_t sm_cmac_sc_buffer[80]; 200 #endif 201 202 // resolvable private address lookup / CSRK calculation 203 static int sm_address_resolution_test; 204 static int sm_address_resolution_ah_calculation_active; 205 static uint8_t sm_address_resolution_addr_type; 206 static bd_addr_t sm_address_resolution_address; 207 static void * sm_address_resolution_context; 208 static address_resolution_mode_t sm_address_resolution_mode; 209 static btstack_linked_list_t sm_address_resolution_general_queue; 210 211 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 212 static sm_aes128_state_t sm_aes128_state; 213 static void * sm_aes128_context; 214 215 // random engine. store context (ususally sm_connection_t) 216 static void * sm_random_context; 217 218 // to receive hci events 219 static btstack_packet_callback_registration_t hci_event_callback_registration; 220 221 /* to dispatch sm event */ 222 static btstack_linked_list_t sm_event_handlers; 223 224 225 // Software ECDH implementation provided by mbedtls 226 #ifdef USE_MBEDTLS_FOR_ECDH 227 // group is always valid 228 static mbedtls_ecp_group mbedtls_ec_group; 229 static ec_key_generation_state_t ec_key_generation_state; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 static uint8_t ec_d[32]; 233 #ifndef HAVE_MALLOC 234 // 4304 bytes with 73 allocations 235 #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 236 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 237 #endif 238 #endif 239 240 // 241 // Volume 3, Part H, Chapter 24 242 // "Security shall be initiated by the Security Manager in the device in the master role. 243 // The device in the slave role shall be the responding device." 244 // -> master := initiator, slave := responder 245 // 246 247 // data needed for security setup 248 typedef struct sm_setup_context { 249 250 btstack_timer_source_t sm_timeout; 251 252 // used in all phases 253 uint8_t sm_pairing_failed_reason; 254 255 // user response, (Phase 1 and/or 2) 256 uint8_t sm_user_response; 257 uint8_t sm_keypress_notification; 258 259 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 260 int sm_key_distribution_send_set; 261 int sm_key_distribution_received_set; 262 263 // Phase 2 (Pairing over SMP) 264 stk_generation_method_t sm_stk_generation_method; 265 sm_key_t sm_tk; 266 uint8_t sm_use_secure_connections; 267 268 sm_key_t sm_c1_t3_value; // c1 calculation 269 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 270 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 271 sm_key_t sm_local_random; 272 sm_key_t sm_local_confirm; 273 sm_key_t sm_peer_random; 274 sm_key_t sm_peer_confirm; 275 uint8_t sm_m_addr_type; // address and type can be removed 276 uint8_t sm_s_addr_type; // '' 277 bd_addr_t sm_m_address; // '' 278 bd_addr_t sm_s_address; // '' 279 sm_key_t sm_ltk; 280 281 uint8_t sm_state_vars; 282 #ifdef ENABLE_LE_SECURE_CONNECTIONS 283 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 284 uint8_t sm_peer_qy[32]; // '' 285 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 286 sm_key_t sm_local_nonce; // might be combined with sm_local_random 287 sm_key_t sm_peer_dhkey_check; 288 sm_key_t sm_local_dhkey_check; 289 sm_key_t sm_ra; 290 sm_key_t sm_rb; 291 sm_key_t sm_t; // used for f5 and h6 292 sm_key_t sm_mackey; 293 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 294 #endif 295 296 // Phase 3 297 298 // key distribution, we generate 299 uint16_t sm_local_y; 300 uint16_t sm_local_div; 301 uint16_t sm_local_ediv; 302 uint8_t sm_local_rand[8]; 303 sm_key_t sm_local_ltk; 304 sm_key_t sm_local_csrk; 305 sm_key_t sm_local_irk; 306 // sm_local_address/addr_type not needed 307 308 // key distribution, received from peer 309 uint16_t sm_peer_y; 310 uint16_t sm_peer_div; 311 uint16_t sm_peer_ediv; 312 uint8_t sm_peer_rand[8]; 313 sm_key_t sm_peer_ltk; 314 sm_key_t sm_peer_irk; 315 sm_key_t sm_peer_csrk; 316 uint8_t sm_peer_addr_type; 317 bd_addr_t sm_peer_address; 318 319 } sm_setup_context_t; 320 321 // 322 static sm_setup_context_t the_setup; 323 static sm_setup_context_t * setup = &the_setup; 324 325 // active connection - the one for which the_setup is used for 326 static uint16_t sm_active_connection = 0; 327 328 // @returns 1 if oob data is available 329 // stores oob data in provided 16 byte buffer if not null 330 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 331 332 // horizontal: initiator capabilities 333 // vertial: responder capabilities 334 static const stk_generation_method_t stk_generation_method [5] [5] = { 335 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 336 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 337 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 338 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 339 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 340 }; 341 342 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 343 #ifdef ENABLE_LE_SECURE_CONNECTIONS 344 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 345 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 346 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 347 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 348 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 349 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 350 }; 351 #endif 352 353 static void sm_run(void); 354 static void sm_done_for_handle(hci_con_handle_t con_handle); 355 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 356 static inline int sm_calc_actual_encryption_key_size(int other); 357 static int sm_validate_stk_generation_method(void); 358 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 359 360 static void log_info_hex16(const char * name, uint16_t value){ 361 log_info("%-6s 0x%04x", name, value); 362 } 363 364 // @returns 1 if all bytes are 0 365 static int sm_is_null(uint8_t * data, int size){ 366 int i; 367 for (i=0; i < size ; i++){ 368 if (data[i]) return 0; 369 } 370 return 1; 371 } 372 373 static int sm_is_null_random(uint8_t random[8]){ 374 return sm_is_null(random, 8); 375 } 376 377 static int sm_is_null_key(uint8_t * key){ 378 return sm_is_null(key, 16); 379 } 380 381 // Key utils 382 static void sm_reset_tk(void){ 383 int i; 384 for (i=0;i<16;i++){ 385 setup->sm_tk[i] = 0; 386 } 387 } 388 389 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 390 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 391 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 392 int i; 393 for (i = max_encryption_size ; i < 16 ; i++){ 394 key[15-i] = 0; 395 } 396 } 397 398 // SMP Timeout implementation 399 400 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 401 // the Security Manager Timer shall be reset and started. 402 // 403 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 404 // 405 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 406 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 407 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 408 // established. 409 410 static void sm_timeout_handler(btstack_timer_source_t * timer){ 411 log_info("SM timeout"); 412 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 413 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 414 sm_done_for_handle(sm_conn->sm_handle); 415 416 // trigger handling of next ready connection 417 sm_run(); 418 } 419 static void sm_timeout_start(sm_connection_t * sm_conn){ 420 btstack_run_loop_remove_timer(&setup->sm_timeout); 421 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 422 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 423 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 424 btstack_run_loop_add_timer(&setup->sm_timeout); 425 } 426 static void sm_timeout_stop(void){ 427 btstack_run_loop_remove_timer(&setup->sm_timeout); 428 } 429 static void sm_timeout_reset(sm_connection_t * sm_conn){ 430 sm_timeout_stop(); 431 sm_timeout_start(sm_conn); 432 } 433 434 // end of sm timeout 435 436 // GAP Random Address updates 437 static gap_random_address_type_t gap_random_adress_type; 438 static btstack_timer_source_t gap_random_address_update_timer; 439 static uint32_t gap_random_adress_update_period; 440 441 static void gap_random_address_trigger(void){ 442 if (rau_state != RAU_IDLE) return; 443 log_info("gap_random_address_trigger"); 444 rau_state = RAU_GET_RANDOM; 445 sm_run(); 446 } 447 448 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 449 log_info("GAP Random Address Update due"); 450 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 451 btstack_run_loop_add_timer(&gap_random_address_update_timer); 452 gap_random_address_trigger(); 453 } 454 455 static void gap_random_address_update_start(void){ 456 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 457 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 458 btstack_run_loop_add_timer(&gap_random_address_update_timer); 459 } 460 461 static void gap_random_address_update_stop(void){ 462 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 463 } 464 465 466 static void sm_random_start(void * context){ 467 sm_random_context = context; 468 hci_send_cmd(&hci_le_rand); 469 } 470 471 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 472 // context is made availabe to aes128 result handler by this 473 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 474 sm_aes128_state = SM_AES128_ACTIVE; 475 sm_key_t key_flipped, plaintext_flipped; 476 reverse_128(key, key_flipped); 477 reverse_128(plaintext, plaintext_flipped); 478 sm_aes128_context = context; 479 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 480 } 481 482 // ah(k,r) helper 483 // r = padding || r 484 // r - 24 bit value 485 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 486 // r'= padding || r 487 memset(r_prime, 0, 16); 488 memcpy(&r_prime[13], r, 3); 489 } 490 491 // d1 helper 492 // d' = padding || r || d 493 // d,r - 16 bit values 494 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 495 // d'= padding || r || d 496 memset(d1_prime, 0, 16); 497 big_endian_store_16(d1_prime, 12, r); 498 big_endian_store_16(d1_prime, 14, d); 499 } 500 501 // dm helper 502 // r’ = padding || r 503 // r - 64 bit value 504 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 505 memset(r_prime, 0, 16); 506 memcpy(&r_prime[8], r, 8); 507 } 508 509 // calculate arguments for first AES128 operation in C1 function 510 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 511 512 // p1 = pres || preq || rat’ || iat’ 513 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 514 // cant octet of pres becomes the most significant octet of p1. 515 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 516 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 517 // p1 is 0x05000800000302070710000001010001." 518 519 sm_key_t p1; 520 reverse_56(pres, &p1[0]); 521 reverse_56(preq, &p1[7]); 522 p1[14] = rat; 523 p1[15] = iat; 524 log_info_key("p1", p1); 525 log_info_key("r", r); 526 527 // t1 = r xor p1 528 int i; 529 for (i=0;i<16;i++){ 530 t1[i] = r[i] ^ p1[i]; 531 } 532 log_info_key("t1", t1); 533 } 534 535 // calculate arguments for second AES128 operation in C1 function 536 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 537 // p2 = padding || ia || ra 538 // "The least significant octet of ra becomes the least significant octet of p2 and 539 // the most significant octet of padding becomes the most significant octet of p2. 540 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 541 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 542 543 sm_key_t p2; 544 memset(p2, 0, 16); 545 memcpy(&p2[4], ia, 6); 546 memcpy(&p2[10], ra, 6); 547 log_info_key("p2", p2); 548 549 // c1 = e(k, t2_xor_p2) 550 int i; 551 for (i=0;i<16;i++){ 552 t3[i] = t2[i] ^ p2[i]; 553 } 554 log_info_key("t3", t3); 555 } 556 557 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 558 log_info_key("r1", r1); 559 log_info_key("r2", r2); 560 memcpy(&r_prime[8], &r2[8], 8); 561 memcpy(&r_prime[0], &r1[8], 8); 562 } 563 564 #ifdef ENABLE_LE_SECURE_CONNECTIONS 565 // Software implementations of crypto toolbox for LE Secure Connection 566 // TODO: replace with code to use AES Engine of HCI Controller 567 typedef uint8_t sm_key24_t[3]; 568 typedef uint8_t sm_key56_t[7]; 569 typedef uint8_t sm_key256_t[32]; 570 571 #if 0 572 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 573 uint32_t rk[RKLENGTH(KEYBITS)]; 574 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 575 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 576 } 577 578 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 579 memcpy(k1, k0, 16); 580 sm_shift_left_by_one_bit_inplace(16, k1); 581 if (k0[0] & 0x80){ 582 k1[15] ^= 0x87; 583 } 584 memcpy(k2, k1, 16); 585 sm_shift_left_by_one_bit_inplace(16, k2); 586 if (k1[0] & 0x80){ 587 k2[15] ^= 0x87; 588 } 589 } 590 591 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 592 sm_key_t k0, k1, k2, zero; 593 memset(zero, 0, 16); 594 595 aes128_calc_cyphertext(key, zero, k0); 596 calc_subkeys(k0, k1, k2); 597 598 int cmac_block_count = (cmac_message_len + 15) / 16; 599 600 // step 3: .. 601 if (cmac_block_count==0){ 602 cmac_block_count = 1; 603 } 604 605 // step 4: set m_last 606 sm_key_t cmac_m_last; 607 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 608 int i; 609 if (sm_cmac_last_block_complete){ 610 for (i=0;i<16;i++){ 611 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 612 } 613 } else { 614 int valid_octets_in_last_block = cmac_message_len & 0x0f; 615 for (i=0;i<16;i++){ 616 if (i < valid_octets_in_last_block){ 617 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 618 continue; 619 } 620 if (i == valid_octets_in_last_block){ 621 cmac_m_last[i] = 0x80 ^ k2[i]; 622 continue; 623 } 624 cmac_m_last[i] = k2[i]; 625 } 626 } 627 628 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 629 // LOG_KEY(cmac_m_last); 630 631 // Step 5 632 sm_key_t cmac_x; 633 memset(cmac_x, 0, 16); 634 635 // Step 6 636 sm_key_t sm_cmac_y; 637 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 638 for (i=0;i<16;i++){ 639 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 640 } 641 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 642 } 643 for (i=0;i<16;i++){ 644 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 645 } 646 647 // Step 7 648 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 649 } 650 #endif 651 #endif 652 653 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 654 event[0] = type; 655 event[1] = event_size - 2; 656 little_endian_store_16(event, 2, con_handle); 657 event[4] = addr_type; 658 reverse_bd_addr(address, &event[5]); 659 } 660 661 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 662 // dispatch to all event handlers 663 btstack_linked_list_iterator_t it; 664 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 665 while (btstack_linked_list_iterator_has_next(&it)){ 666 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 667 entry->callback(packet_type, 0, packet, size); 668 } 669 } 670 671 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 672 uint8_t event[11]; 673 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 674 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 675 } 676 677 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 678 uint8_t event[15]; 679 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 680 little_endian_store_32(event, 11, passkey); 681 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 682 } 683 684 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 685 uint8_t event[13]; 686 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 687 little_endian_store_16(event, 11, index); 688 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 689 } 690 691 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 692 693 uint8_t event[18]; 694 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 695 event[11] = result; 696 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 697 } 698 699 // decide on stk generation based on 700 // - pairing request 701 // - io capabilities 702 // - OOB data availability 703 static void sm_setup_tk(void){ 704 705 // default: just works 706 setup->sm_stk_generation_method = JUST_WORKS; 707 708 #ifdef ENABLE_LE_SECURE_CONNECTIONS 709 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 710 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 711 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 712 memset(setup->sm_ra, 0, 16); 713 memset(setup->sm_rb, 0, 16); 714 #else 715 setup->sm_use_secure_connections = 0; 716 #endif 717 718 // If both devices have not set the MITM option in the Authentication Requirements 719 // Flags, then the IO capabilities shall be ignored and the Just Works association 720 // model shall be used. 721 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 722 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 723 log_info("SM: MITM not required by both -> JUST WORKS"); 724 return; 725 } 726 727 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 728 729 // If both devices have out of band authentication data, then the Authentication 730 // Requirements Flags shall be ignored when selecting the pairing method and the 731 // Out of Band pairing method shall be used. 732 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 733 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 734 log_info("SM: have OOB data"); 735 log_info_key("OOB", setup->sm_tk); 736 setup->sm_stk_generation_method = OOB; 737 return; 738 } 739 740 // Reset TK as it has been setup in sm_init_setup 741 sm_reset_tk(); 742 743 // Also use just works if unknown io capabilites 744 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 745 return; 746 } 747 748 // Otherwise the IO capabilities of the devices shall be used to determine the 749 // pairing method as defined in Table 2.4. 750 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 751 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 752 753 #ifdef ENABLE_LE_SECURE_CONNECTIONS 754 // table not define by default 755 if (setup->sm_use_secure_connections){ 756 generation_method = stk_generation_method_with_secure_connection; 757 } 758 #endif 759 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 760 761 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 762 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 763 } 764 765 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 766 int flags = 0; 767 if (key_set & SM_KEYDIST_ENC_KEY){ 768 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 769 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 770 } 771 if (key_set & SM_KEYDIST_ID_KEY){ 772 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 773 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 774 } 775 if (key_set & SM_KEYDIST_SIGN){ 776 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 777 } 778 return flags; 779 } 780 781 static void sm_setup_key_distribution(uint8_t key_set){ 782 setup->sm_key_distribution_received_set = 0; 783 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 784 } 785 786 // CSRK Key Lookup 787 788 789 static int sm_address_resolution_idle(void){ 790 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 791 } 792 793 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 794 memcpy(sm_address_resolution_address, addr, 6); 795 sm_address_resolution_addr_type = addr_type; 796 sm_address_resolution_test = 0; 797 sm_address_resolution_mode = mode; 798 sm_address_resolution_context = context; 799 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 800 } 801 802 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 803 // check if already in list 804 btstack_linked_list_iterator_t it; 805 sm_lookup_entry_t * entry; 806 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 807 while(btstack_linked_list_iterator_has_next(&it)){ 808 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 809 if (entry->address_type != address_type) continue; 810 if (memcmp(entry->address, address, 6)) continue; 811 // already in list 812 return BTSTACK_BUSY; 813 } 814 entry = btstack_memory_sm_lookup_entry_get(); 815 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 816 entry->address_type = (bd_addr_type_t) address_type; 817 memcpy(entry->address, address, 6); 818 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 819 sm_run(); 820 return 0; 821 } 822 823 // CMAC Implementation using AES128 engine 824 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 825 int i; 826 int carry = 0; 827 for (i=len-1; i >= 0 ; i--){ 828 int new_carry = data[i] >> 7; 829 data[i] = data[i] << 1 | carry; 830 carry = new_carry; 831 } 832 } 833 834 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 835 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 836 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 837 } 838 static inline void dkg_next_state(void){ 839 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 840 } 841 static inline void rau_next_state(void){ 842 rau_state = (random_address_update_t) (((int)rau_state) + 1); 843 } 844 845 // CMAC calculation using AES Engine 846 847 static inline void sm_cmac_next_state(void){ 848 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 849 } 850 851 static int sm_cmac_last_block_complete(void){ 852 if (sm_cmac_message_len == 0) return 0; 853 return (sm_cmac_message_len & 0x0f) == 0; 854 } 855 856 int sm_cmac_ready(void){ 857 return sm_cmac_state == CMAC_IDLE; 858 } 859 860 // generic cmac calculation 861 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 862 // Generalized CMAC 863 memcpy(sm_cmac_k, key, 16); 864 memset(sm_cmac_x, 0, 16); 865 sm_cmac_block_current = 0; 866 sm_cmac_message_len = message_len; 867 sm_cmac_done_handler = done_callback; 868 sm_cmac_get_byte = get_byte_callback; 869 870 // step 2: n := ceil(len/const_Bsize); 871 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 872 873 // step 3: .. 874 if (sm_cmac_block_count==0){ 875 sm_cmac_block_count = 1; 876 } 877 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 878 879 // first, we need to compute l for k1, k2, and m_last 880 sm_cmac_state = CMAC_CALC_SUBKEYS; 881 882 // let's go 883 sm_run(); 884 } 885 886 // cmac for ATT Message signing 887 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 888 if (offset >= sm_cmac_message_len) { 889 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 890 return 0; 891 } 892 893 offset = sm_cmac_message_len - 1 - offset; 894 895 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 896 if (offset < 3){ 897 return sm_cmac_header[offset]; 898 } 899 int actual_message_len_incl_header = sm_cmac_message_len - 4; 900 if (offset < actual_message_len_incl_header){ 901 return sm_cmac_message[offset - 3]; 902 } 903 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 904 } 905 906 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 907 // ATT Message Signing 908 sm_cmac_header[0] = opcode; 909 little_endian_store_16(sm_cmac_header, 1, con_handle); 910 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 911 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 912 sm_cmac_message = message; 913 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 914 } 915 916 917 static void sm_cmac_handle_aes_engine_ready(void){ 918 switch (sm_cmac_state){ 919 case CMAC_CALC_SUBKEYS: { 920 sm_key_t const_zero; 921 memset(const_zero, 0, 16); 922 sm_cmac_next_state(); 923 sm_aes128_start(sm_cmac_k, const_zero, NULL); 924 break; 925 } 926 case CMAC_CALC_MI: { 927 int j; 928 sm_key_t y; 929 for (j=0;j<16;j++){ 930 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 931 } 932 sm_cmac_block_current++; 933 sm_cmac_next_state(); 934 sm_aes128_start(sm_cmac_k, y, NULL); 935 break; 936 } 937 case CMAC_CALC_MLAST: { 938 int i; 939 sm_key_t y; 940 for (i=0;i<16;i++){ 941 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 942 } 943 log_info_key("Y", y); 944 sm_cmac_block_current++; 945 sm_cmac_next_state(); 946 sm_aes128_start(sm_cmac_k, y, NULL); 947 break; 948 } 949 default: 950 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 951 break; 952 } 953 } 954 955 static void sm_cmac_handle_encryption_result(sm_key_t data){ 956 switch (sm_cmac_state){ 957 case CMAC_W4_SUBKEYS: { 958 sm_key_t k1; 959 memcpy(k1, data, 16); 960 sm_shift_left_by_one_bit_inplace(16, k1); 961 if (data[0] & 0x80){ 962 k1[15] ^= 0x87; 963 } 964 sm_key_t k2; 965 memcpy(k2, k1, 16); 966 sm_shift_left_by_one_bit_inplace(16, k2); 967 if (k1[0] & 0x80){ 968 k2[15] ^= 0x87; 969 } 970 971 log_info_key("k", sm_cmac_k); 972 log_info_key("k1", k1); 973 log_info_key("k2", k2); 974 975 // step 4: set m_last 976 int i; 977 if (sm_cmac_last_block_complete()){ 978 for (i=0;i<16;i++){ 979 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 980 } 981 } else { 982 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 983 for (i=0;i<16;i++){ 984 if (i < valid_octets_in_last_block){ 985 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 986 continue; 987 } 988 if (i == valid_octets_in_last_block){ 989 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 990 continue; 991 } 992 sm_cmac_m_last[i] = k2[i]; 993 } 994 } 995 996 // next 997 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 998 break; 999 } 1000 case CMAC_W4_MI: 1001 memcpy(sm_cmac_x, data, 16); 1002 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1003 break; 1004 case CMAC_W4_MLAST: 1005 // done 1006 log_info("Setting CMAC Engine to IDLE"); 1007 sm_cmac_state = CMAC_IDLE; 1008 log_info_key("CMAC", data); 1009 sm_cmac_done_handler(data); 1010 break; 1011 default: 1012 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1013 break; 1014 } 1015 } 1016 1017 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1018 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1019 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1020 switch (setup->sm_stk_generation_method){ 1021 case PK_RESP_INPUT: 1022 if (sm_conn->sm_role){ 1023 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1024 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1025 } else { 1026 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1027 } 1028 break; 1029 case PK_INIT_INPUT: 1030 if (sm_conn->sm_role){ 1031 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1032 } else { 1033 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1034 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1035 } 1036 break; 1037 case OK_BOTH_INPUT: 1038 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1039 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1040 break; 1041 case NK_BOTH_INPUT: 1042 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1043 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1044 break; 1045 case JUST_WORKS: 1046 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1047 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1048 break; 1049 case OOB: 1050 // client already provided OOB data, let's skip notification. 1051 break; 1052 } 1053 } 1054 1055 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1056 int recv_flags; 1057 if (sm_conn->sm_role){ 1058 // slave / responder 1059 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1060 } else { 1061 // master / initiator 1062 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1063 } 1064 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1065 return recv_flags == setup->sm_key_distribution_received_set; 1066 } 1067 1068 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1069 if (sm_active_connection == con_handle){ 1070 sm_timeout_stop(); 1071 sm_active_connection = 0; 1072 log_info("sm: connection 0x%x released setup context", con_handle); 1073 } 1074 } 1075 1076 static int sm_key_distribution_flags_for_auth_req(void){ 1077 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1078 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1079 // encryption information only if bonding requested 1080 flags |= SM_KEYDIST_ENC_KEY; 1081 } 1082 return flags; 1083 } 1084 1085 static void sm_init_setup(sm_connection_t * sm_conn){ 1086 1087 // fill in sm setup 1088 setup->sm_state_vars = 0; 1089 setup->sm_keypress_notification = 0xff; 1090 sm_reset_tk(); 1091 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1092 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1093 1094 // query client for OOB data 1095 int have_oob_data = 0; 1096 if (sm_get_oob_data) { 1097 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1098 } 1099 1100 sm_pairing_packet_t * local_packet; 1101 if (sm_conn->sm_role){ 1102 // slave 1103 local_packet = &setup->sm_s_pres; 1104 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1105 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1106 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1107 } else { 1108 // master 1109 local_packet = &setup->sm_m_preq; 1110 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1111 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1112 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1113 1114 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1115 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1116 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1117 } 1118 1119 uint8_t auth_req = sm_auth_req; 1120 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1121 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1122 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1123 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1124 } 1125 1126 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1127 1128 sm_pairing_packet_t * remote_packet; 1129 int remote_key_request; 1130 if (sm_conn->sm_role){ 1131 // slave / responder 1132 remote_packet = &setup->sm_m_preq; 1133 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1134 } else { 1135 // master / initiator 1136 remote_packet = &setup->sm_s_pres; 1137 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1138 } 1139 1140 // check key size 1141 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1142 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1143 1144 // decide on STK generation method 1145 sm_setup_tk(); 1146 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1147 1148 // check if STK generation method is acceptable by client 1149 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1150 1151 // identical to responder 1152 sm_setup_key_distribution(remote_key_request); 1153 1154 // JUST WORKS doens't provide authentication 1155 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1156 1157 return 0; 1158 } 1159 1160 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1161 1162 // cache and reset context 1163 int matched_device_id = sm_address_resolution_test; 1164 address_resolution_mode_t mode = sm_address_resolution_mode; 1165 void * context = sm_address_resolution_context; 1166 1167 // reset context 1168 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1169 sm_address_resolution_context = NULL; 1170 sm_address_resolution_test = -1; 1171 hci_con_handle_t con_handle = 0; 1172 1173 sm_connection_t * sm_connection; 1174 uint16_t ediv; 1175 switch (mode){ 1176 case ADDRESS_RESOLUTION_GENERAL: 1177 break; 1178 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1179 sm_connection = (sm_connection_t *) context; 1180 con_handle = sm_connection->sm_handle; 1181 switch (event){ 1182 case ADDRESS_RESOLUTION_SUCEEDED: 1183 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1184 sm_connection->sm_le_db_index = matched_device_id; 1185 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1186 if (sm_connection->sm_role) break; 1187 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1188 sm_connection->sm_security_request_received = 0; 1189 sm_connection->sm_bonding_requested = 0; 1190 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1191 if (ediv){ 1192 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1193 } else { 1194 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1195 } 1196 break; 1197 case ADDRESS_RESOLUTION_FAILED: 1198 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1199 if (sm_connection->sm_role) break; 1200 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1201 sm_connection->sm_security_request_received = 0; 1202 sm_connection->sm_bonding_requested = 0; 1203 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1204 break; 1205 } 1206 break; 1207 default: 1208 break; 1209 } 1210 1211 switch (event){ 1212 case ADDRESS_RESOLUTION_SUCEEDED: 1213 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1214 break; 1215 case ADDRESS_RESOLUTION_FAILED: 1216 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1217 break; 1218 } 1219 } 1220 1221 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1222 1223 int le_db_index = -1; 1224 1225 // lookup device based on IRK 1226 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1227 int i; 1228 for (i=0; i < le_device_db_count(); i++){ 1229 sm_key_t irk; 1230 bd_addr_t address; 1231 int address_type; 1232 le_device_db_info(i, &address_type, address, irk); 1233 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1234 log_info("sm: device found for IRK, updating"); 1235 le_db_index = i; 1236 break; 1237 } 1238 } 1239 } 1240 1241 // if not found, lookup via public address if possible 1242 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1243 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1244 int i; 1245 for (i=0; i < le_device_db_count(); i++){ 1246 bd_addr_t address; 1247 int address_type; 1248 le_device_db_info(i, &address_type, address, NULL); 1249 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1250 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1251 log_info("sm: device found for public address, updating"); 1252 le_db_index = i; 1253 break; 1254 } 1255 } 1256 } 1257 1258 // if not found, add to db 1259 if (le_db_index < 0) { 1260 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1261 } 1262 1263 if (le_db_index >= 0){ 1264 1265 // store local CSRK 1266 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1267 log_info("sm: store local CSRK"); 1268 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1269 le_device_db_local_counter_set(le_db_index, 0); 1270 } 1271 1272 // store remote CSRK 1273 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1274 log_info("sm: store remote CSRK"); 1275 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1276 le_device_db_remote_counter_set(le_db_index, 0); 1277 } 1278 1279 // store encryption information for secure connections: LTK generated by ECDH 1280 if (setup->sm_use_secure_connections){ 1281 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1282 uint8_t zero_rand[8]; 1283 memset(zero_rand, 0, 8); 1284 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1285 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1286 } 1287 1288 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1289 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1290 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1291 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1292 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1293 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1294 1295 } 1296 } 1297 1298 // keep le_db_index 1299 sm_conn->sm_le_db_index = le_db_index; 1300 } 1301 1302 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1303 setup->sm_pairing_failed_reason = reason; 1304 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1305 } 1306 1307 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1308 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1309 } 1310 1311 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1312 1313 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1314 static int sm_passkey_used(stk_generation_method_t method); 1315 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1316 1317 static void sm_log_ec_keypair(void){ 1318 log_info("Elliptic curve: d"); 1319 log_info_hexdump(ec_d,32); 1320 log_info("Elliptic curve: X"); 1321 log_info_hexdump(ec_qx,32); 1322 log_info("Elliptic curve: Y"); 1323 log_info_hexdump(ec_qy,32); 1324 } 1325 1326 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1327 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1328 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1329 } else { 1330 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1331 } 1332 } 1333 1334 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1335 if (sm_conn->sm_role){ 1336 // Responder 1337 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1338 } else { 1339 // Initiator role 1340 switch (setup->sm_stk_generation_method){ 1341 case JUST_WORKS: 1342 sm_sc_prepare_dhkey_check(sm_conn); 1343 break; 1344 1345 case NK_BOTH_INPUT: 1346 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1347 break; 1348 case PK_INIT_INPUT: 1349 case PK_RESP_INPUT: 1350 case OK_BOTH_INPUT: 1351 if (setup->sm_passkey_bit < 20) { 1352 sm_sc_start_calculating_local_confirm(sm_conn); 1353 } else { 1354 sm_sc_prepare_dhkey_check(sm_conn); 1355 } 1356 break; 1357 case OOB: 1358 // TODO: implement SC OOB 1359 break; 1360 } 1361 } 1362 } 1363 1364 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1365 return sm_cmac_sc_buffer[offset]; 1366 } 1367 1368 static void sm_sc_cmac_done(uint8_t * hash){ 1369 log_info("sm_sc_cmac_done: "); 1370 log_info_hexdump(hash, 16); 1371 1372 sm_connection_t * sm_conn = sm_cmac_connection; 1373 sm_cmac_connection = NULL; 1374 link_key_type_t link_key_type; 1375 1376 switch (sm_conn->sm_engine_state){ 1377 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1378 memcpy(setup->sm_local_confirm, hash, 16); 1379 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1380 break; 1381 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1382 // check 1383 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1384 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1385 break; 1386 } 1387 sm_sc_state_after_receiving_random(sm_conn); 1388 break; 1389 case SM_SC_W4_CALCULATE_G2: { 1390 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1391 big_endian_store_32(setup->sm_tk, 12, vab); 1392 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1393 sm_trigger_user_response(sm_conn); 1394 break; 1395 } 1396 case SM_SC_W4_CALCULATE_F5_SALT: 1397 memcpy(setup->sm_t, hash, 16); 1398 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1399 break; 1400 case SM_SC_W4_CALCULATE_F5_MACKEY: 1401 memcpy(setup->sm_mackey, hash, 16); 1402 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1403 break; 1404 case SM_SC_W4_CALCULATE_F5_LTK: 1405 memcpy(setup->sm_ltk, hash, 16); 1406 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1407 break; 1408 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1409 memcpy(setup->sm_local_dhkey_check, hash, 16); 1410 if (sm_conn->sm_role){ 1411 // responder 1412 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1413 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1414 } else { 1415 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1416 } 1417 } else { 1418 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1419 } 1420 break; 1421 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1422 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1423 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1424 break; 1425 } 1426 if (sm_conn->sm_role){ 1427 // responder 1428 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1429 } else { 1430 // initiator 1431 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1432 } 1433 break; 1434 case SM_SC_W4_CALCULATE_H6_ILK: 1435 memcpy(setup->sm_t, hash, 16); 1436 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1437 break; 1438 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1439 reverse_128(hash, setup->sm_t); 1440 link_key_type = sm_conn->sm_connection_authenticated ? 1441 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1442 if (sm_conn->sm_role){ 1443 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1444 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1445 } else { 1446 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1447 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1448 } 1449 sm_done_for_handle(sm_conn->sm_handle); 1450 break; 1451 default: 1452 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1453 break; 1454 } 1455 sm_run(); 1456 } 1457 1458 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1459 const uint16_t message_len = 65; 1460 sm_cmac_connection = sm_conn; 1461 memcpy(sm_cmac_sc_buffer, u, 32); 1462 memcpy(sm_cmac_sc_buffer+32, v, 32); 1463 sm_cmac_sc_buffer[64] = z; 1464 log_info("f4 key"); 1465 log_info_hexdump(x, 16); 1466 log_info("f4 message"); 1467 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1468 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1469 } 1470 1471 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1472 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1473 static const uint8_t f5_length[] = { 0x01, 0x00}; 1474 1475 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1476 #ifdef USE_MBEDTLS_FOR_ECDH 1477 // da * Pb 1478 mbedtls_mpi d; 1479 mbedtls_ecp_point Q; 1480 mbedtls_ecp_point DH; 1481 mbedtls_mpi_init(&d); 1482 mbedtls_ecp_point_init(&Q); 1483 mbedtls_ecp_point_init(&DH); 1484 mbedtls_mpi_read_binary(&d, ec_d, 32); 1485 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1486 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1487 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1488 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1489 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1490 mbedtls_mpi_free(&d); 1491 mbedtls_ecp_point_free(&Q); 1492 mbedtls_ecp_point_free(&DH); 1493 #endif 1494 log_info("dhkey"); 1495 log_info_hexdump(dhkey, 32); 1496 } 1497 1498 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1499 // calculate DHKEY 1500 sm_key256_t dhkey; 1501 sm_sc_calculate_dhkey(dhkey); 1502 1503 // calculate salt for f5 1504 const uint16_t message_len = 32; 1505 sm_cmac_connection = sm_conn; 1506 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1507 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1508 } 1509 1510 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1511 const uint16_t message_len = 53; 1512 sm_cmac_connection = sm_conn; 1513 1514 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1515 sm_cmac_sc_buffer[0] = 0; 1516 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1517 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1518 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1519 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1520 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1521 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1522 log_info("f5 key"); 1523 log_info_hexdump(t, 16); 1524 log_info("f5 message for MacKey"); 1525 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1526 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1527 } 1528 1529 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1530 sm_key56_t bd_addr_master, bd_addr_slave; 1531 bd_addr_master[0] = setup->sm_m_addr_type; 1532 bd_addr_slave[0] = setup->sm_s_addr_type; 1533 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1534 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1535 if (sm_conn->sm_role){ 1536 // responder 1537 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1538 } else { 1539 // initiator 1540 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1541 } 1542 } 1543 1544 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1545 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1546 const uint16_t message_len = 53; 1547 sm_cmac_connection = sm_conn; 1548 sm_cmac_sc_buffer[0] = 1; 1549 // 1..52 setup before 1550 log_info("f5 key"); 1551 log_info_hexdump(t, 16); 1552 log_info("f5 message for LTK"); 1553 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1554 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1555 } 1556 1557 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1558 f5_ltk(sm_conn, setup->sm_t); 1559 } 1560 1561 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1562 const uint16_t message_len = 65; 1563 sm_cmac_connection = sm_conn; 1564 memcpy(sm_cmac_sc_buffer, n1, 16); 1565 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1566 memcpy(sm_cmac_sc_buffer+32, r, 16); 1567 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1568 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1569 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1570 log_info("f6 key"); 1571 log_info_hexdump(w, 16); 1572 log_info("f6 message"); 1573 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1574 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1575 } 1576 1577 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1578 // - U is 256 bits 1579 // - V is 256 bits 1580 // - X is 128 bits 1581 // - Y is 128 bits 1582 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1583 const uint16_t message_len = 80; 1584 sm_cmac_connection = sm_conn; 1585 memcpy(sm_cmac_sc_buffer, u, 32); 1586 memcpy(sm_cmac_sc_buffer+32, v, 32); 1587 memcpy(sm_cmac_sc_buffer+64, y, 16); 1588 log_info("g2 key"); 1589 log_info_hexdump(x, 16); 1590 log_info("g2 message"); 1591 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1592 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1593 } 1594 1595 static void g2_calculate(sm_connection_t * sm_conn) { 1596 // calc Va if numeric comparison 1597 if (sm_conn->sm_role){ 1598 // responder 1599 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1600 } else { 1601 // initiator 1602 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1603 } 1604 } 1605 1606 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1607 uint8_t z = 0; 1608 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1609 // some form of passkey 1610 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1611 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1612 setup->sm_passkey_bit++; 1613 } 1614 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1615 } 1616 1617 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1618 uint8_t z = 0; 1619 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1620 // some form of passkey 1621 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1622 // sm_passkey_bit was increased before sending confirm value 1623 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1624 } 1625 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1626 } 1627 1628 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1629 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1630 } 1631 1632 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1633 // calculate DHKCheck 1634 sm_key56_t bd_addr_master, bd_addr_slave; 1635 bd_addr_master[0] = setup->sm_m_addr_type; 1636 bd_addr_slave[0] = setup->sm_s_addr_type; 1637 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1638 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1639 uint8_t iocap_a[3]; 1640 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1641 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1642 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1643 uint8_t iocap_b[3]; 1644 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1645 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1646 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1647 if (sm_conn->sm_role){ 1648 // responder 1649 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1650 } else { 1651 // initiator 1652 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1653 } 1654 } 1655 1656 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1657 // validate E = f6() 1658 sm_key56_t bd_addr_master, bd_addr_slave; 1659 bd_addr_master[0] = setup->sm_m_addr_type; 1660 bd_addr_slave[0] = setup->sm_s_addr_type; 1661 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1662 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1663 1664 uint8_t iocap_a[3]; 1665 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1666 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1667 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1668 uint8_t iocap_b[3]; 1669 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1670 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1671 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1672 if (sm_conn->sm_role){ 1673 // responder 1674 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1675 } else { 1676 // initiator 1677 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1678 } 1679 } 1680 1681 1682 // 1683 // Link Key Conversion Function h6 1684 // 1685 // h6(W, keyID) = AES-CMACW(keyID) 1686 // - W is 128 bits 1687 // - keyID is 32 bits 1688 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1689 const uint16_t message_len = 4; 1690 sm_cmac_connection = sm_conn; 1691 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1692 log_info("h6 key"); 1693 log_info_hexdump(w, 16); 1694 log_info("h6 message"); 1695 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1696 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1697 } 1698 1699 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1700 h6_engine(sm_conn, setup->sm_ltk, 0x746D7031); // "tmp1" 1701 } 1702 1703 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1704 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1705 } 1706 1707 #endif 1708 1709 // key management legacy connections: 1710 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1711 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1712 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1713 // - responder reconnects: responder uses LTK receveived from master 1714 1715 // key management secure connections: 1716 // - both devices store same LTK from ECDH key exchange. 1717 1718 static void sm_load_security_info(sm_connection_t * sm_connection){ 1719 int encryption_key_size; 1720 int authenticated; 1721 int authorized; 1722 1723 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1724 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1725 &encryption_key_size, &authenticated, &authorized); 1726 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1727 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1728 sm_connection->sm_connection_authenticated = authenticated; 1729 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1730 } 1731 1732 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1733 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1734 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1735 // re-establish used key encryption size 1736 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1737 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1738 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1739 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1740 log_info("sm: received ltk request with key size %u, authenticated %u", 1741 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1742 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1743 } 1744 1745 static void sm_run(void){ 1746 1747 btstack_linked_list_iterator_t it; 1748 1749 // assert that we can send at least commands 1750 if (!hci_can_send_command_packet_now()) return; 1751 1752 // 1753 // non-connection related behaviour 1754 // 1755 1756 // distributed key generation 1757 switch (dkg_state){ 1758 case DKG_CALC_IRK: 1759 // already busy? 1760 if (sm_aes128_state == SM_AES128_IDLE) { 1761 // IRK = d1(IR, 1, 0) 1762 sm_key_t d1_prime; 1763 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1764 dkg_next_state(); 1765 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1766 return; 1767 } 1768 break; 1769 case DKG_CALC_DHK: 1770 // already busy? 1771 if (sm_aes128_state == SM_AES128_IDLE) { 1772 // DHK = d1(IR, 3, 0) 1773 sm_key_t d1_prime; 1774 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1775 dkg_next_state(); 1776 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1777 return; 1778 } 1779 break; 1780 default: 1781 break; 1782 } 1783 1784 #ifdef USE_MBEDTLS_FOR_ECDH 1785 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1786 sm_random_start(NULL); 1787 return; 1788 } 1789 #endif 1790 1791 // random address updates 1792 switch (rau_state){ 1793 case RAU_GET_RANDOM: 1794 rau_next_state(); 1795 sm_random_start(NULL); 1796 return; 1797 case RAU_GET_ENC: 1798 // already busy? 1799 if (sm_aes128_state == SM_AES128_IDLE) { 1800 sm_key_t r_prime; 1801 sm_ah_r_prime(sm_random_address, r_prime); 1802 rau_next_state(); 1803 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1804 return; 1805 } 1806 break; 1807 case RAU_SET_ADDRESS: 1808 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1809 rau_state = RAU_IDLE; 1810 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1811 return; 1812 default: 1813 break; 1814 } 1815 1816 // CMAC 1817 switch (sm_cmac_state){ 1818 case CMAC_CALC_SUBKEYS: 1819 case CMAC_CALC_MI: 1820 case CMAC_CALC_MLAST: 1821 // already busy? 1822 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1823 sm_cmac_handle_aes_engine_ready(); 1824 return; 1825 default: 1826 break; 1827 } 1828 1829 // CSRK Lookup 1830 // -- if csrk lookup ready, find connection that require csrk lookup 1831 if (sm_address_resolution_idle()){ 1832 hci_connections_get_iterator(&it); 1833 while(btstack_linked_list_iterator_has_next(&it)){ 1834 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1835 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1836 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1837 // and start lookup 1838 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1839 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1840 break; 1841 } 1842 } 1843 } 1844 1845 // -- if csrk lookup ready, resolved addresses for received addresses 1846 if (sm_address_resolution_idle()) { 1847 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1848 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1849 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1850 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1851 btstack_memory_sm_lookup_entry_free(entry); 1852 } 1853 } 1854 1855 // -- Continue with CSRK device lookup by public or resolvable private address 1856 if (!sm_address_resolution_idle()){ 1857 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1858 while (sm_address_resolution_test < le_device_db_count()){ 1859 int addr_type; 1860 bd_addr_t addr; 1861 sm_key_t irk; 1862 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1863 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1864 1865 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1866 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1867 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1868 break; 1869 } 1870 1871 if (sm_address_resolution_addr_type == 0){ 1872 sm_address_resolution_test++; 1873 continue; 1874 } 1875 1876 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1877 1878 log_info("LE Device Lookup: calculate AH"); 1879 log_info_key("IRK", irk); 1880 1881 sm_key_t r_prime; 1882 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1883 sm_address_resolution_ah_calculation_active = 1; 1884 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1885 return; 1886 } 1887 1888 if (sm_address_resolution_test >= le_device_db_count()){ 1889 log_info("LE Device Lookup: not found"); 1890 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1891 } 1892 } 1893 1894 1895 // 1896 // active connection handling 1897 // -- use loop to handle next connection if lock on setup context is released 1898 1899 while (1) { 1900 1901 // Find connections that requires setup context and make active if no other is locked 1902 hci_connections_get_iterator(&it); 1903 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1904 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1905 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1906 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1907 int done = 1; 1908 int err; 1909 switch (sm_connection->sm_engine_state) { 1910 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1911 // send packet if possible, 1912 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1913 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1914 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1915 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1916 } else { 1917 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1918 } 1919 // don't lock sxetup context yet 1920 done = 0; 1921 break; 1922 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1923 sm_init_setup(sm_connection); 1924 // recover pairing request 1925 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1926 err = sm_stk_generation_init(sm_connection); 1927 if (err){ 1928 setup->sm_pairing_failed_reason = err; 1929 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1930 break; 1931 } 1932 sm_timeout_start(sm_connection); 1933 // generate random number first, if we need to show passkey 1934 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1935 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1936 break; 1937 } 1938 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1939 break; 1940 case SM_INITIATOR_PH0_HAS_LTK: 1941 sm_load_security_info(sm_connection); 1942 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1943 break; 1944 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1945 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1946 switch (sm_connection->sm_irk_lookup_state){ 1947 case IRK_LOOKUP_SUCCEEDED: 1948 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 1949 sm_load_security_info(sm_connection); 1950 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 1951 sm_connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1952 break; 1953 } 1954 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 1955 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1956 // don't lock setup context yet 1957 done = 0; 1958 break; 1959 case IRK_LOOKUP_FAILED: 1960 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1961 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1962 // don't lock setup context yet 1963 done = 0; 1964 break; 1965 default: 1966 // just wait until IRK lookup is completed 1967 // don't lock setup context yet 1968 done = 0; 1969 break; 1970 } 1971 #endif 1972 break; 1973 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1974 sm_init_setup(sm_connection); 1975 sm_timeout_start(sm_connection); 1976 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1977 break; 1978 default: 1979 done = 0; 1980 break; 1981 } 1982 if (done){ 1983 sm_active_connection = sm_connection->sm_handle; 1984 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1985 } 1986 } 1987 1988 // 1989 // active connection handling 1990 // 1991 1992 if (sm_active_connection == 0) return; 1993 1994 // assert that we could send a SM PDU - not needed for all of the following 1995 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1996 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1997 return; 1998 } 1999 2000 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2001 if (!connection) return; 2002 2003 // send keypress notifications 2004 if (setup->sm_keypress_notification != 0xff){ 2005 uint8_t buffer[2]; 2006 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2007 buffer[1] = setup->sm_keypress_notification; 2008 setup->sm_keypress_notification = 0xff; 2009 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2010 } 2011 2012 sm_key_t plaintext; 2013 int key_distribution_flags; 2014 2015 log_info("sm_run: state %u", connection->sm_engine_state); 2016 2017 // responding state 2018 switch (connection->sm_engine_state){ 2019 2020 // general 2021 case SM_GENERAL_SEND_PAIRING_FAILED: { 2022 uint8_t buffer[2]; 2023 buffer[0] = SM_CODE_PAIRING_FAILED; 2024 buffer[1] = setup->sm_pairing_failed_reason; 2025 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2026 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2027 sm_done_for_handle(connection->sm_handle); 2028 break; 2029 } 2030 2031 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2032 case SM_SC_W2_GET_RANDOM_A: 2033 sm_random_start(connection); 2034 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2035 break; 2036 case SM_SC_W2_GET_RANDOM_B: 2037 sm_random_start(connection); 2038 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2039 break; 2040 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2041 if (!sm_cmac_ready()) break; 2042 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2043 sm_sc_calculate_local_confirm(connection); 2044 break; 2045 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2046 if (!sm_cmac_ready()) break; 2047 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2048 sm_sc_calculate_remote_confirm(connection); 2049 break; 2050 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2051 if (!sm_cmac_ready()) break; 2052 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2053 sm_sc_calculate_f6_for_dhkey_check(connection); 2054 break; 2055 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2056 if (!sm_cmac_ready()) break; 2057 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2058 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2059 break; 2060 case SM_SC_W2_CALCULATE_F5_SALT: 2061 if (!sm_cmac_ready()) break; 2062 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2063 f5_calculate_salt(connection); 2064 break; 2065 case SM_SC_W2_CALCULATE_F5_MACKEY: 2066 if (!sm_cmac_ready()) break; 2067 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2068 f5_calculate_mackey(connection); 2069 break; 2070 case SM_SC_W2_CALCULATE_F5_LTK: 2071 if (!sm_cmac_ready()) break; 2072 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2073 f5_calculate_ltk(connection); 2074 break; 2075 case SM_SC_W2_CALCULATE_G2: 2076 if (!sm_cmac_ready()) break; 2077 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2078 g2_calculate(connection); 2079 break; 2080 case SM_SC_W2_CALCULATE_H6_ILK: 2081 if (!sm_cmac_ready()) break; 2082 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2083 h6_calculate_ilk(connection); 2084 break; 2085 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2086 if (!sm_cmac_ready()) break; 2087 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2088 h6_calculate_br_edr_link_key(connection); 2089 break; 2090 2091 #endif 2092 // initiator side 2093 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2094 sm_key_t peer_ltk_flipped; 2095 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2096 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2097 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2098 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2099 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2100 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2101 return; 2102 } 2103 2104 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2105 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2106 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2107 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2108 sm_timeout_reset(connection); 2109 break; 2110 2111 // responder side 2112 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2113 connection->sm_engine_state = SM_RESPONDER_IDLE; 2114 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2115 sm_done_for_handle(connection->sm_handle); 2116 return; 2117 2118 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2119 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2120 uint8_t buffer[65]; 2121 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2122 // 2123 reverse_256(ec_qx, &buffer[1]); 2124 reverse_256(ec_qy, &buffer[33]); 2125 2126 // stk generation method 2127 // passkey entry: notify app to show passkey or to request passkey 2128 switch (setup->sm_stk_generation_method){ 2129 case JUST_WORKS: 2130 case NK_BOTH_INPUT: 2131 if (connection->sm_role){ 2132 // responder 2133 sm_sc_start_calculating_local_confirm(connection); 2134 } else { 2135 // initiator 2136 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2137 } 2138 break; 2139 case PK_INIT_INPUT: 2140 case PK_RESP_INPUT: 2141 case OK_BOTH_INPUT: 2142 // use random TK for display 2143 memcpy(setup->sm_ra, setup->sm_tk, 16); 2144 memcpy(setup->sm_rb, setup->sm_tk, 16); 2145 setup->sm_passkey_bit = 0; 2146 2147 if (connection->sm_role){ 2148 // responder 2149 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2150 } else { 2151 // initiator 2152 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2153 } 2154 sm_trigger_user_response(connection); 2155 break; 2156 case OOB: 2157 // TODO: implement SC OOB 2158 break; 2159 } 2160 2161 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2162 sm_timeout_reset(connection); 2163 break; 2164 } 2165 case SM_SC_SEND_CONFIRMATION: { 2166 uint8_t buffer[17]; 2167 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2168 reverse_128(setup->sm_local_confirm, &buffer[1]); 2169 if (connection->sm_role){ 2170 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2171 } else { 2172 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2173 } 2174 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2175 sm_timeout_reset(connection); 2176 break; 2177 } 2178 case SM_SC_SEND_PAIRING_RANDOM: { 2179 uint8_t buffer[17]; 2180 buffer[0] = SM_CODE_PAIRING_RANDOM; 2181 reverse_128(setup->sm_local_nonce, &buffer[1]); 2182 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2183 if (connection->sm_role){ 2184 // responder 2185 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2186 } else { 2187 // initiator 2188 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2189 } 2190 } else { 2191 if (connection->sm_role){ 2192 // responder 2193 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2194 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2195 } else { 2196 sm_sc_prepare_dhkey_check(connection); 2197 } 2198 } else { 2199 // initiator 2200 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2201 } 2202 } 2203 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2204 sm_timeout_reset(connection); 2205 break; 2206 } 2207 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2208 uint8_t buffer[17]; 2209 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2210 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2211 2212 if (connection->sm_role){ 2213 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2214 } else { 2215 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2216 } 2217 2218 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2219 sm_timeout_reset(connection); 2220 break; 2221 } 2222 2223 #endif 2224 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2225 // echo initiator for now 2226 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2227 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2228 2229 if (setup->sm_use_secure_connections){ 2230 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2231 // skip LTK/EDIV for SC 2232 log_info("sm: dropping encryption information flag"); 2233 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2234 } else { 2235 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2236 } 2237 2238 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); 2239 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); 2240 // update key distribution after ENC was dropped 2241 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2242 2243 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2244 sm_timeout_reset(connection); 2245 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2246 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2247 sm_trigger_user_response(connection); 2248 } 2249 return; 2250 2251 case SM_PH2_SEND_PAIRING_RANDOM: { 2252 uint8_t buffer[17]; 2253 buffer[0] = SM_CODE_PAIRING_RANDOM; 2254 reverse_128(setup->sm_local_random, &buffer[1]); 2255 if (connection->sm_role){ 2256 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2257 } else { 2258 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2259 } 2260 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2261 sm_timeout_reset(connection); 2262 break; 2263 } 2264 2265 case SM_PH2_GET_RANDOM_TK: 2266 case SM_PH2_C1_GET_RANDOM_A: 2267 case SM_PH2_C1_GET_RANDOM_B: 2268 case SM_PH3_GET_RANDOM: 2269 case SM_PH3_GET_DIV: 2270 sm_next_responding_state(connection); 2271 sm_random_start(connection); 2272 return; 2273 2274 case SM_PH2_C1_GET_ENC_B: 2275 case SM_PH2_C1_GET_ENC_D: 2276 // already busy? 2277 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2278 sm_next_responding_state(connection); 2279 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2280 return; 2281 2282 case SM_PH3_LTK_GET_ENC: 2283 case SM_RESPONDER_PH4_LTK_GET_ENC: 2284 // already busy? 2285 if (sm_aes128_state == SM_AES128_IDLE) { 2286 sm_key_t d_prime; 2287 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2288 sm_next_responding_state(connection); 2289 sm_aes128_start(sm_persistent_er, d_prime, connection); 2290 return; 2291 } 2292 break; 2293 2294 case SM_PH3_CSRK_GET_ENC: 2295 // already busy? 2296 if (sm_aes128_state == SM_AES128_IDLE) { 2297 sm_key_t d_prime; 2298 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2299 sm_next_responding_state(connection); 2300 sm_aes128_start(sm_persistent_er, d_prime, connection); 2301 return; 2302 } 2303 break; 2304 2305 case SM_PH2_C1_GET_ENC_C: 2306 // already busy? 2307 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2308 // calculate m_confirm using aes128 engine - step 1 2309 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); 2310 sm_next_responding_state(connection); 2311 sm_aes128_start(setup->sm_tk, plaintext, connection); 2312 break; 2313 case SM_PH2_C1_GET_ENC_A: 2314 // already busy? 2315 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2316 // calculate confirm using aes128 engine - step 1 2317 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); 2318 sm_next_responding_state(connection); 2319 sm_aes128_start(setup->sm_tk, plaintext, connection); 2320 break; 2321 case SM_PH2_CALC_STK: 2322 // already busy? 2323 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2324 // calculate STK 2325 if (connection->sm_role){ 2326 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2327 } else { 2328 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2329 } 2330 sm_next_responding_state(connection); 2331 sm_aes128_start(setup->sm_tk, plaintext, connection); 2332 break; 2333 case SM_PH3_Y_GET_ENC: 2334 // already busy? 2335 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2336 // PH3B2 - calculate Y from - enc 2337 // Y = dm(DHK, Rand) 2338 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2339 sm_next_responding_state(connection); 2340 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2341 return; 2342 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2343 uint8_t buffer[17]; 2344 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2345 reverse_128(setup->sm_local_confirm, &buffer[1]); 2346 if (connection->sm_role){ 2347 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2348 } else { 2349 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2350 } 2351 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2352 sm_timeout_reset(connection); 2353 return; 2354 } 2355 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2356 sm_key_t stk_flipped; 2357 reverse_128(setup->sm_ltk, stk_flipped); 2358 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2359 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2360 return; 2361 } 2362 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2363 sm_key_t stk_flipped; 2364 reverse_128(setup->sm_ltk, stk_flipped); 2365 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2366 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2367 return; 2368 } 2369 case SM_RESPONDER_PH4_SEND_LTK: { 2370 sm_key_t ltk_flipped; 2371 reverse_128(setup->sm_ltk, ltk_flipped); 2372 connection->sm_engine_state = SM_RESPONDER_IDLE; 2373 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2374 return; 2375 } 2376 case SM_RESPONDER_PH4_Y_GET_ENC: 2377 // already busy? 2378 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2379 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2380 // Y = dm(DHK, Rand) 2381 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2382 sm_next_responding_state(connection); 2383 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2384 return; 2385 2386 case SM_PH3_DISTRIBUTE_KEYS: 2387 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2388 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2389 uint8_t buffer[17]; 2390 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2391 reverse_128(setup->sm_ltk, &buffer[1]); 2392 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2393 sm_timeout_reset(connection); 2394 return; 2395 } 2396 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2397 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2398 uint8_t buffer[11]; 2399 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2400 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2401 reverse_64(setup->sm_local_rand, &buffer[3]); 2402 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2403 sm_timeout_reset(connection); 2404 return; 2405 } 2406 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2407 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2408 uint8_t buffer[17]; 2409 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2410 reverse_128(sm_persistent_irk, &buffer[1]); 2411 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2412 sm_timeout_reset(connection); 2413 return; 2414 } 2415 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2416 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2417 bd_addr_t local_address; 2418 uint8_t buffer[8]; 2419 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2420 gap_advertisements_get_address(&buffer[1], local_address); 2421 reverse_bd_addr(local_address, &buffer[2]); 2422 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2423 sm_timeout_reset(connection); 2424 return; 2425 } 2426 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2427 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2428 2429 // hack to reproduce test runs 2430 if (test_use_fixed_local_csrk){ 2431 memset(setup->sm_local_csrk, 0xcc, 16); 2432 } 2433 2434 uint8_t buffer[17]; 2435 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2436 reverse_128(setup->sm_local_csrk, &buffer[1]); 2437 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2438 sm_timeout_reset(connection); 2439 return; 2440 } 2441 2442 // keys are sent 2443 if (connection->sm_role){ 2444 // slave -> receive master keys if any 2445 if (sm_key_distribution_all_received(connection)){ 2446 sm_key_distribution_handle_all_received(connection); 2447 connection->sm_engine_state = SM_RESPONDER_IDLE; 2448 sm_done_for_handle(connection->sm_handle); 2449 } else { 2450 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2451 } 2452 } else { 2453 // master -> all done 2454 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2455 sm_done_for_handle(connection->sm_handle); 2456 } 2457 break; 2458 2459 default: 2460 break; 2461 } 2462 2463 // check again if active connection was released 2464 if (sm_active_connection) break; 2465 } 2466 } 2467 2468 // note: aes engine is ready as we just got the aes result 2469 static void sm_handle_encryption_result(uint8_t * data){ 2470 2471 sm_aes128_state = SM_AES128_IDLE; 2472 2473 if (sm_address_resolution_ah_calculation_active){ 2474 sm_address_resolution_ah_calculation_active = 0; 2475 // compare calulated address against connecting device 2476 uint8_t hash[3]; 2477 reverse_24(data, hash); 2478 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2479 log_info("LE Device Lookup: matched resolvable private address"); 2480 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2481 return; 2482 } 2483 // no match, try next 2484 sm_address_resolution_test++; 2485 return; 2486 } 2487 2488 switch (dkg_state){ 2489 case DKG_W4_IRK: 2490 reverse_128(data, sm_persistent_irk); 2491 log_info_key("irk", sm_persistent_irk); 2492 dkg_next_state(); 2493 return; 2494 case DKG_W4_DHK: 2495 reverse_128(data, sm_persistent_dhk); 2496 log_info_key("dhk", sm_persistent_dhk); 2497 dkg_next_state(); 2498 // SM Init Finished 2499 return; 2500 default: 2501 break; 2502 } 2503 2504 switch (rau_state){ 2505 case RAU_W4_ENC: 2506 reverse_24(data, &sm_random_address[3]); 2507 rau_next_state(); 2508 return; 2509 default: 2510 break; 2511 } 2512 2513 switch (sm_cmac_state){ 2514 case CMAC_W4_SUBKEYS: 2515 case CMAC_W4_MI: 2516 case CMAC_W4_MLAST: 2517 { 2518 sm_key_t t; 2519 reverse_128(data, t); 2520 sm_cmac_handle_encryption_result(t); 2521 } 2522 return; 2523 default: 2524 break; 2525 } 2526 2527 // retrieve sm_connection provided to sm_aes128_start_encryption 2528 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2529 if (!connection) return; 2530 switch (connection->sm_engine_state){ 2531 case SM_PH2_C1_W4_ENC_A: 2532 case SM_PH2_C1_W4_ENC_C: 2533 { 2534 sm_key_t t2; 2535 reverse_128(data, t2); 2536 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2537 } 2538 sm_next_responding_state(connection); 2539 return; 2540 case SM_PH2_C1_W4_ENC_B: 2541 reverse_128(data, setup->sm_local_confirm); 2542 log_info_key("c1!", setup->sm_local_confirm); 2543 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2544 return; 2545 case SM_PH2_C1_W4_ENC_D: 2546 { 2547 sm_key_t peer_confirm_test; 2548 reverse_128(data, peer_confirm_test); 2549 log_info_key("c1!", peer_confirm_test); 2550 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2551 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2552 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2553 return; 2554 } 2555 if (connection->sm_role){ 2556 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2557 } else { 2558 connection->sm_engine_state = SM_PH2_CALC_STK; 2559 } 2560 } 2561 return; 2562 case SM_PH2_W4_STK: 2563 reverse_128(data, setup->sm_ltk); 2564 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2565 log_info_key("stk", setup->sm_ltk); 2566 if (connection->sm_role){ 2567 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2568 } else { 2569 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2570 } 2571 return; 2572 case SM_PH3_Y_W4_ENC:{ 2573 sm_key_t y128; 2574 reverse_128(data, y128); 2575 setup->sm_local_y = big_endian_read_16(y128, 14); 2576 log_info_hex16("y", setup->sm_local_y); 2577 // PH3B3 - calculate EDIV 2578 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2579 log_info_hex16("ediv", setup->sm_local_ediv); 2580 // PH3B4 - calculate LTK - enc 2581 // LTK = d1(ER, DIV, 0)) 2582 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2583 return; 2584 } 2585 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2586 sm_key_t y128; 2587 reverse_128(data, y128); 2588 setup->sm_local_y = big_endian_read_16(y128, 14); 2589 log_info_hex16("y", setup->sm_local_y); 2590 2591 // PH3B3 - calculate DIV 2592 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2593 log_info_hex16("ediv", setup->sm_local_ediv); 2594 // PH3B4 - calculate LTK - enc 2595 // LTK = d1(ER, DIV, 0)) 2596 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2597 return; 2598 } 2599 case SM_PH3_LTK_W4_ENC: 2600 reverse_128(data, setup->sm_ltk); 2601 log_info_key("ltk", setup->sm_ltk); 2602 // calc CSRK next 2603 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2604 return; 2605 case SM_PH3_CSRK_W4_ENC: 2606 reverse_128(data, setup->sm_local_csrk); 2607 log_info_key("csrk", setup->sm_local_csrk); 2608 if (setup->sm_key_distribution_send_set){ 2609 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2610 } else { 2611 // no keys to send, just continue 2612 if (connection->sm_role){ 2613 // slave -> receive master keys 2614 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2615 } else { 2616 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2617 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2618 } else { 2619 // master -> all done 2620 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2621 sm_done_for_handle(connection->sm_handle); 2622 } 2623 } 2624 } 2625 return; 2626 case SM_RESPONDER_PH4_LTK_W4_ENC: 2627 reverse_128(data, setup->sm_ltk); 2628 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2629 log_info_key("ltk", setup->sm_ltk); 2630 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2631 return; 2632 default: 2633 break; 2634 } 2635 } 2636 2637 #ifdef USE_MBEDTLS_FOR_ECDH 2638 2639 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2640 int offset = setup->sm_passkey_bit; 2641 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2642 while (size) { 2643 if (offset < 32){ 2644 *buffer++ = setup->sm_peer_qx[offset++]; 2645 } else { 2646 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2647 } 2648 size--; 2649 } 2650 setup->sm_passkey_bit = offset; 2651 return 0; 2652 } 2653 #endif 2654 2655 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2656 static void sm_handle_random_result(uint8_t * data){ 2657 2658 #ifdef USE_MBEDTLS_FOR_ECDH 2659 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2660 int num_bytes = setup->sm_passkey_bit; 2661 if (num_bytes < 32){ 2662 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2663 } else { 2664 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2665 } 2666 num_bytes += 8; 2667 setup->sm_passkey_bit = num_bytes; 2668 2669 if (num_bytes >= 64){ 2670 // generate EC key 2671 setup->sm_passkey_bit = 0; 2672 mbedtls_mpi d; 2673 mbedtls_ecp_point P; 2674 mbedtls_mpi_init(&d); 2675 mbedtls_ecp_point_init(&P); 2676 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2677 log_info("gen keypair %x", res); 2678 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2679 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2680 mbedtls_mpi_write_binary(&d, ec_d, 32); 2681 mbedtls_ecp_point_free(&P); 2682 mbedtls_mpi_free(&d); 2683 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2684 sm_log_ec_keypair(); 2685 2686 #if 0 2687 printf("test dhkey check\n"); 2688 sm_key256_t dhkey; 2689 memcpy(setup->sm_peer_qx, ec_qx, 32); 2690 memcpy(setup->sm_peer_qy, ec_qy, 32); 2691 sm_sc_calculate_dhkey(dhkey); 2692 #endif 2693 2694 } 2695 } 2696 #endif 2697 2698 switch (rau_state){ 2699 case RAU_W4_RANDOM: 2700 // non-resolvable vs. resolvable 2701 switch (gap_random_adress_type){ 2702 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2703 // resolvable: use random as prand and calc address hash 2704 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2705 memcpy(sm_random_address, data, 3); 2706 sm_random_address[0] &= 0x3f; 2707 sm_random_address[0] |= 0x40; 2708 rau_state = RAU_GET_ENC; 2709 break; 2710 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2711 default: 2712 // "The two most significant bits of the address shall be equal to ‘0’"" 2713 memcpy(sm_random_address, data, 6); 2714 sm_random_address[0] &= 0x3f; 2715 rau_state = RAU_SET_ADDRESS; 2716 break; 2717 } 2718 return; 2719 default: 2720 break; 2721 } 2722 2723 // retrieve sm_connection provided to sm_random_start 2724 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2725 if (!connection) return; 2726 switch (connection->sm_engine_state){ 2727 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2728 case SM_SC_W4_GET_RANDOM_A: 2729 memcpy(&setup->sm_local_nonce[0], data, 8); 2730 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2731 break; 2732 case SM_SC_W4_GET_RANDOM_B: 2733 memcpy(&setup->sm_local_nonce[8], data, 8); 2734 // initiator & jw/nc -> send pairing random 2735 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2736 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2737 break; 2738 } else { 2739 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2740 } 2741 break; 2742 #endif 2743 2744 case SM_PH2_W4_RANDOM_TK: 2745 { 2746 // map random to 0-999999 without speding much cycles on a modulus operation 2747 uint32_t tk = little_endian_read_32(data,0); 2748 tk = tk & 0xfffff; // 1048575 2749 if (tk >= 999999){ 2750 tk = tk - 999999; 2751 } 2752 sm_reset_tk(); 2753 big_endian_store_32(setup->sm_tk, 12, tk); 2754 if (connection->sm_role){ 2755 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2756 } else { 2757 if (setup->sm_use_secure_connections){ 2758 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2759 } else { 2760 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2761 sm_trigger_user_response(connection); 2762 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2763 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2764 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2765 } 2766 } 2767 } 2768 return; 2769 } 2770 case SM_PH2_C1_W4_RANDOM_A: 2771 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2772 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2773 return; 2774 case SM_PH2_C1_W4_RANDOM_B: 2775 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2776 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2777 return; 2778 case SM_PH3_W4_RANDOM: 2779 reverse_64(data, setup->sm_local_rand); 2780 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2781 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2782 // no db for authenticated flag hack: store flag in bit 4 of LSB 2783 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2784 connection->sm_engine_state = SM_PH3_GET_DIV; 2785 return; 2786 case SM_PH3_W4_DIV: 2787 // use 16 bit from random value as div 2788 setup->sm_local_div = big_endian_read_16(data, 0); 2789 log_info_hex16("div", setup->sm_local_div); 2790 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2791 return; 2792 default: 2793 break; 2794 } 2795 } 2796 2797 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2798 2799 sm_connection_t * sm_conn; 2800 hci_con_handle_t con_handle; 2801 2802 switch (packet_type) { 2803 2804 case HCI_EVENT_PACKET: 2805 switch (hci_event_packet_get_type(packet)) { 2806 2807 case BTSTACK_EVENT_STATE: 2808 // bt stack activated, get started 2809 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2810 log_info("HCI Working!"); 2811 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2812 rau_state = RAU_IDLE; 2813 #ifdef USE_MBEDTLS_FOR_ECDH 2814 if (!sm_have_ec_keypair){ 2815 setup->sm_passkey_bit = 0; 2816 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2817 } 2818 #endif 2819 sm_run(); 2820 } 2821 break; 2822 2823 case HCI_EVENT_LE_META: 2824 switch (packet[2]) { 2825 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2826 2827 log_info("sm: connected"); 2828 2829 if (packet[3]) return; // connection failed 2830 2831 con_handle = little_endian_read_16(packet, 4); 2832 sm_conn = sm_get_connection_for_handle(con_handle); 2833 if (!sm_conn) break; 2834 2835 sm_conn->sm_handle = con_handle; 2836 sm_conn->sm_role = packet[6]; 2837 sm_conn->sm_peer_addr_type = packet[7]; 2838 reverse_bd_addr(&packet[8], 2839 sm_conn->sm_peer_address); 2840 2841 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2842 2843 // reset security properties 2844 sm_conn->sm_connection_encrypted = 0; 2845 sm_conn->sm_connection_authenticated = 0; 2846 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2847 sm_conn->sm_le_db_index = -1; 2848 2849 // prepare CSRK lookup (does not involve setup) 2850 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2851 2852 // just connected -> everything else happens in sm_run() 2853 if (sm_conn->sm_role){ 2854 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2855 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2856 if (sm_slave_request_security) { 2857 // request security if requested by app 2858 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2859 } else { 2860 // otherwise, wait for pairing request 2861 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2862 } 2863 } 2864 break; 2865 } else { 2866 // master 2867 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2868 } 2869 break; 2870 2871 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2872 con_handle = little_endian_read_16(packet, 3); 2873 sm_conn = sm_get_connection_for_handle(con_handle); 2874 if (!sm_conn) break; 2875 2876 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2877 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2878 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2879 break; 2880 } 2881 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2882 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2883 break; 2884 } 2885 2886 // store rand and ediv 2887 reverse_64(&packet[5], sm_conn->sm_local_rand); 2888 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2889 2890 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2891 // potentially stored LTK is from the master 2892 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2893 sm_start_calculating_ltk_from_ediv_and_rand(sm_conn); 2894 break; 2895 } 2896 2897 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2898 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2899 #else 2900 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2901 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2902 #endif 2903 break; 2904 2905 default: 2906 break; 2907 } 2908 break; 2909 2910 case HCI_EVENT_ENCRYPTION_CHANGE: 2911 con_handle = little_endian_read_16(packet, 3); 2912 sm_conn = sm_get_connection_for_handle(con_handle); 2913 if (!sm_conn) break; 2914 2915 sm_conn->sm_connection_encrypted = packet[5]; 2916 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2917 sm_conn->sm_actual_encryption_key_size); 2918 log_info("event handler, state %u", sm_conn->sm_engine_state); 2919 if (!sm_conn->sm_connection_encrypted) break; 2920 // continue if part of initial pairing 2921 switch (sm_conn->sm_engine_state){ 2922 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2923 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2924 sm_done_for_handle(sm_conn->sm_handle); 2925 break; 2926 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2927 if (sm_conn->sm_role){ 2928 // slave 2929 if (setup->sm_use_secure_connections){ 2930 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2931 } else { 2932 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2933 } 2934 } else { 2935 // master 2936 if (sm_key_distribution_all_received(sm_conn)){ 2937 // skip receiving keys as there are none 2938 sm_key_distribution_handle_all_received(sm_conn); 2939 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2940 } else { 2941 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2942 } 2943 } 2944 break; 2945 default: 2946 break; 2947 } 2948 break; 2949 2950 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2951 con_handle = little_endian_read_16(packet, 3); 2952 sm_conn = sm_get_connection_for_handle(con_handle); 2953 if (!sm_conn) break; 2954 2955 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2956 log_info("event handler, state %u", sm_conn->sm_engine_state); 2957 // continue if part of initial pairing 2958 switch (sm_conn->sm_engine_state){ 2959 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2960 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2961 sm_done_for_handle(sm_conn->sm_handle); 2962 break; 2963 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2964 if (sm_conn->sm_role){ 2965 // slave 2966 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2967 } else { 2968 // master 2969 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2970 } 2971 break; 2972 default: 2973 break; 2974 } 2975 break; 2976 2977 2978 case HCI_EVENT_DISCONNECTION_COMPLETE: 2979 con_handle = little_endian_read_16(packet, 3); 2980 sm_done_for_handle(con_handle); 2981 sm_conn = sm_get_connection_for_handle(con_handle); 2982 if (!sm_conn) break; 2983 2984 // delete stored bonding on disconnect with authentication failure in ph0 2985 if (sm_conn->sm_role == 0 2986 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2987 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2988 le_device_db_remove(sm_conn->sm_le_db_index); 2989 } 2990 2991 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2992 sm_conn->sm_handle = 0; 2993 break; 2994 2995 case HCI_EVENT_COMMAND_COMPLETE: 2996 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2997 sm_handle_encryption_result(&packet[6]); 2998 break; 2999 } 3000 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3001 sm_handle_random_result(&packet[6]); 3002 break; 3003 } 3004 break; 3005 default: 3006 break; 3007 } 3008 break; 3009 default: 3010 break; 3011 } 3012 3013 sm_run(); 3014 } 3015 3016 static inline int sm_calc_actual_encryption_key_size(int other){ 3017 if (other < sm_min_encryption_key_size) return 0; 3018 if (other < sm_max_encryption_key_size) return other; 3019 return sm_max_encryption_key_size; 3020 } 3021 3022 3023 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3024 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3025 switch (method){ 3026 case JUST_WORKS: 3027 case NK_BOTH_INPUT: 3028 return 1; 3029 default: 3030 return 0; 3031 } 3032 } 3033 // responder 3034 3035 static int sm_passkey_used(stk_generation_method_t method){ 3036 switch (method){ 3037 case PK_RESP_INPUT: 3038 return 1; 3039 default: 3040 return 0; 3041 } 3042 } 3043 #endif 3044 3045 /** 3046 * @return ok 3047 */ 3048 static int sm_validate_stk_generation_method(void){ 3049 // check if STK generation method is acceptable by client 3050 switch (setup->sm_stk_generation_method){ 3051 case JUST_WORKS: 3052 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3053 case PK_RESP_INPUT: 3054 case PK_INIT_INPUT: 3055 case OK_BOTH_INPUT: 3056 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3057 case OOB: 3058 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3059 case NK_BOTH_INPUT: 3060 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3061 return 1; 3062 default: 3063 return 0; 3064 } 3065 } 3066 3067 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3068 3069 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3070 sm_run(); 3071 } 3072 3073 if (packet_type != SM_DATA_PACKET) return; 3074 3075 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3076 if (!sm_conn) return; 3077 3078 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3079 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3080 return; 3081 } 3082 3083 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3084 3085 int err; 3086 3087 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3088 uint8_t buffer[5]; 3089 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3090 buffer[1] = 3; 3091 little_endian_store_16(buffer, 2, con_handle); 3092 buffer[4] = packet[1]; 3093 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3094 return; 3095 } 3096 3097 switch (sm_conn->sm_engine_state){ 3098 3099 // a sm timeout requries a new physical connection 3100 case SM_GENERAL_TIMEOUT: 3101 return; 3102 3103 // Initiator 3104 case SM_INITIATOR_CONNECTED: 3105 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3106 sm_pdu_received_in_wrong_state(sm_conn); 3107 break; 3108 } 3109 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3110 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3111 break; 3112 } 3113 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3114 sm_key_t ltk; 3115 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3116 if (!sm_is_null_key(ltk)){ 3117 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3118 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3119 } else { 3120 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3121 } 3122 break; 3123 } 3124 // otherwise, store security request 3125 sm_conn->sm_security_request_received = 1; 3126 break; 3127 3128 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3129 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3130 sm_pdu_received_in_wrong_state(sm_conn); 3131 break; 3132 } 3133 // store pairing request 3134 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3135 err = sm_stk_generation_init(sm_conn); 3136 if (err){ 3137 setup->sm_pairing_failed_reason = err; 3138 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3139 break; 3140 } 3141 3142 // generate random number first, if we need to show passkey 3143 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3144 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3145 break; 3146 } 3147 3148 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3149 if (setup->sm_use_secure_connections){ 3150 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3151 if (setup->sm_stk_generation_method == JUST_WORKS){ 3152 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3153 sm_trigger_user_response(sm_conn); 3154 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3155 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3156 } 3157 } else { 3158 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3159 } 3160 break; 3161 } 3162 #endif 3163 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3164 sm_trigger_user_response(sm_conn); 3165 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3166 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3167 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3168 } 3169 break; 3170 3171 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3172 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3173 sm_pdu_received_in_wrong_state(sm_conn); 3174 break; 3175 } 3176 3177 // store s_confirm 3178 reverse_128(&packet[1], setup->sm_peer_confirm); 3179 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3180 break; 3181 3182 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3183 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3184 sm_pdu_received_in_wrong_state(sm_conn); 3185 break;; 3186 } 3187 3188 // received random value 3189 reverse_128(&packet[1], setup->sm_peer_random); 3190 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3191 break; 3192 3193 // Responder 3194 case SM_RESPONDER_IDLE: 3195 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3196 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3197 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3198 sm_pdu_received_in_wrong_state(sm_conn); 3199 break;; 3200 } 3201 3202 // store pairing request 3203 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3204 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3205 break; 3206 3207 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3208 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3209 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3210 sm_pdu_received_in_wrong_state(sm_conn); 3211 break; 3212 } 3213 3214 // store public key for DH Key calculation 3215 reverse_256(&packet[01], setup->sm_peer_qx); 3216 reverse_256(&packet[33], setup->sm_peer_qy); 3217 3218 #ifdef USE_MBEDTLS_FOR_ECDH 3219 // validate public key 3220 mbedtls_ecp_point Q; 3221 mbedtls_ecp_point_init( &Q ); 3222 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3223 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3224 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3225 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3226 mbedtls_ecp_point_free( & Q); 3227 if (err){ 3228 log_error("sm: peer public key invalid %x", err); 3229 // uses "unspecified reason", there is no "public key invalid" error code 3230 sm_pdu_received_in_wrong_state(sm_conn); 3231 break; 3232 } 3233 3234 #endif 3235 if (sm_conn->sm_role){ 3236 // responder 3237 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3238 } else { 3239 // initiator 3240 // stk generation method 3241 // passkey entry: notify app to show passkey or to request passkey 3242 switch (setup->sm_stk_generation_method){ 3243 case JUST_WORKS: 3244 case NK_BOTH_INPUT: 3245 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3246 break; 3247 case PK_RESP_INPUT: 3248 sm_sc_start_calculating_local_confirm(sm_conn); 3249 break; 3250 case PK_INIT_INPUT: 3251 case OK_BOTH_INPUT: 3252 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3253 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3254 break; 3255 } 3256 sm_sc_start_calculating_local_confirm(sm_conn); 3257 break; 3258 case OOB: 3259 // TODO: implement SC OOB 3260 break; 3261 } 3262 } 3263 break; 3264 3265 case SM_SC_W4_CONFIRMATION: 3266 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3267 sm_pdu_received_in_wrong_state(sm_conn); 3268 break; 3269 } 3270 // received confirm value 3271 reverse_128(&packet[1], setup->sm_peer_confirm); 3272 3273 if (sm_conn->sm_role){ 3274 // responder 3275 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3276 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3277 // still waiting for passkey 3278 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3279 break; 3280 } 3281 } 3282 sm_sc_start_calculating_local_confirm(sm_conn); 3283 } else { 3284 // initiator 3285 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3286 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3287 } else { 3288 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3289 } 3290 } 3291 break; 3292 3293 case SM_SC_W4_PAIRING_RANDOM: 3294 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3295 sm_pdu_received_in_wrong_state(sm_conn); 3296 break; 3297 } 3298 3299 // received random value 3300 reverse_128(&packet[1], setup->sm_peer_nonce); 3301 3302 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3303 // only check for JUST WORK/NC in initiator role AND passkey entry 3304 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3305 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3306 } 3307 3308 sm_sc_state_after_receiving_random(sm_conn); 3309 break; 3310 3311 case SM_SC_W2_CALCULATE_G2: 3312 case SM_SC_W4_CALCULATE_G2: 3313 case SM_SC_W2_CALCULATE_F5_SALT: 3314 case SM_SC_W4_CALCULATE_F5_SALT: 3315 case SM_SC_W2_CALCULATE_F5_MACKEY: 3316 case SM_SC_W4_CALCULATE_F5_MACKEY: 3317 case SM_SC_W2_CALCULATE_F5_LTK: 3318 case SM_SC_W4_CALCULATE_F5_LTK: 3319 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3320 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3321 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3322 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3323 sm_pdu_received_in_wrong_state(sm_conn); 3324 break; 3325 } 3326 // store DHKey Check 3327 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3328 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3329 3330 // have we been only waiting for dhkey check command? 3331 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3332 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3333 } 3334 break; 3335 #endif 3336 3337 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3338 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3339 sm_pdu_received_in_wrong_state(sm_conn); 3340 break; 3341 } 3342 3343 // received confirm value 3344 reverse_128(&packet[1], setup->sm_peer_confirm); 3345 3346 // notify client to hide shown passkey 3347 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3348 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3349 } 3350 3351 // handle user cancel pairing? 3352 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3353 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3354 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3355 break; 3356 } 3357 3358 // wait for user action? 3359 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3360 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3361 break; 3362 } 3363 3364 // calculate and send local_confirm 3365 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3366 break; 3367 3368 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3369 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3370 sm_pdu_received_in_wrong_state(sm_conn); 3371 break;; 3372 } 3373 3374 // received random value 3375 reverse_128(&packet[1], setup->sm_peer_random); 3376 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3377 break; 3378 3379 case SM_PH3_RECEIVE_KEYS: 3380 switch(packet[0]){ 3381 case SM_CODE_ENCRYPTION_INFORMATION: 3382 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3383 reverse_128(&packet[1], setup->sm_peer_ltk); 3384 break; 3385 3386 case SM_CODE_MASTER_IDENTIFICATION: 3387 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3388 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3389 reverse_64(&packet[3], setup->sm_peer_rand); 3390 break; 3391 3392 case SM_CODE_IDENTITY_INFORMATION: 3393 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3394 reverse_128(&packet[1], setup->sm_peer_irk); 3395 break; 3396 3397 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3398 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3399 setup->sm_peer_addr_type = packet[1]; 3400 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3401 break; 3402 3403 case SM_CODE_SIGNING_INFORMATION: 3404 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3405 reverse_128(&packet[1], setup->sm_peer_csrk); 3406 break; 3407 default: 3408 // Unexpected PDU 3409 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3410 break; 3411 } 3412 // done with key distribution? 3413 if (sm_key_distribution_all_received(sm_conn)){ 3414 3415 sm_key_distribution_handle_all_received(sm_conn); 3416 3417 if (sm_conn->sm_role){ 3418 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3419 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3420 } else { 3421 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3422 sm_done_for_handle(sm_conn->sm_handle); 3423 } 3424 } else { 3425 if (setup->sm_use_secure_connections){ 3426 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3427 } else { 3428 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3429 } 3430 } 3431 } 3432 break; 3433 default: 3434 // Unexpected PDU 3435 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3436 break; 3437 } 3438 3439 // try to send preparared packet 3440 sm_run(); 3441 } 3442 3443 // Security Manager Client API 3444 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3445 sm_get_oob_data = get_oob_data_callback; 3446 } 3447 3448 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3449 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3450 } 3451 3452 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3453 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3454 } 3455 3456 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3457 sm_min_encryption_key_size = min_size; 3458 sm_max_encryption_key_size = max_size; 3459 } 3460 3461 void sm_set_authentication_requirements(uint8_t auth_req){ 3462 sm_auth_req = auth_req; 3463 } 3464 3465 void sm_set_io_capabilities(io_capability_t io_capability){ 3466 sm_io_capabilities = io_capability; 3467 } 3468 3469 void sm_set_request_security(int enable){ 3470 sm_slave_request_security = enable; 3471 } 3472 3473 void sm_set_er(sm_key_t er){ 3474 memcpy(sm_persistent_er, er, 16); 3475 } 3476 3477 void sm_set_ir(sm_key_t ir){ 3478 memcpy(sm_persistent_ir, ir, 16); 3479 } 3480 3481 // Testing support only 3482 void sm_test_set_irk(sm_key_t irk){ 3483 memcpy(sm_persistent_irk, irk, 16); 3484 sm_persistent_irk_ready = 1; 3485 } 3486 3487 void sm_test_use_fixed_local_csrk(void){ 3488 test_use_fixed_local_csrk = 1; 3489 } 3490 3491 void sm_init(void){ 3492 // set some (BTstack default) ER and IR 3493 int i; 3494 sm_key_t er; 3495 sm_key_t ir; 3496 for (i=0;i<16;i++){ 3497 er[i] = 0x30 + i; 3498 ir[i] = 0x90 + i; 3499 } 3500 sm_set_er(er); 3501 sm_set_ir(ir); 3502 // defaults 3503 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3504 | SM_STK_GENERATION_METHOD_OOB 3505 | SM_STK_GENERATION_METHOD_PASSKEY 3506 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3507 3508 sm_max_encryption_key_size = 16; 3509 sm_min_encryption_key_size = 7; 3510 3511 sm_cmac_state = CMAC_IDLE; 3512 dkg_state = DKG_W4_WORKING; 3513 rau_state = RAU_W4_WORKING; 3514 sm_aes128_state = SM_AES128_IDLE; 3515 sm_address_resolution_test = -1; // no private address to resolve yet 3516 sm_address_resolution_ah_calculation_active = 0; 3517 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3518 sm_address_resolution_general_queue = NULL; 3519 3520 gap_random_adress_update_period = 15 * 60 * 1000L; 3521 3522 sm_active_connection = 0; 3523 3524 test_use_fixed_local_csrk = 0; 3525 3526 // register for HCI Events from HCI 3527 hci_event_callback_registration.callback = &sm_event_packet_handler; 3528 hci_add_event_handler(&hci_event_callback_registration); 3529 3530 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3531 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3532 3533 #ifdef USE_MBEDTLS_FOR_ECDH 3534 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3535 3536 #ifndef HAVE_MALLOC 3537 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3538 #endif 3539 mbedtls_ecp_group_init(&mbedtls_ec_group); 3540 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3541 3542 #if 0 3543 // test 3544 sm_test_use_fixed_ec_keypair(); 3545 if (sm_have_ec_keypair){ 3546 printf("test dhkey check\n"); 3547 sm_key256_t dhkey; 3548 memcpy(setup->sm_peer_qx, ec_qx, 32); 3549 memcpy(setup->sm_peer_qy, ec_qy, 32); 3550 sm_sc_calculate_dhkey(dhkey); 3551 } 3552 #endif 3553 #endif 3554 } 3555 3556 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3557 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3558 memcpy(ec_qx, qx, 32); 3559 memcpy(ec_qy, qy, 32); 3560 memcpy(ec_d, d, 32); 3561 sm_have_ec_keypair = 1; 3562 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3563 #endif 3564 } 3565 3566 void sm_test_use_fixed_ec_keypair(void){ 3567 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3568 #ifdef USE_MBEDTLS_FOR_ECDH 3569 // use test keypair from spec 3570 mbedtls_mpi x; 3571 mbedtls_mpi_init(&x); 3572 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3573 mbedtls_mpi_write_binary(&x, ec_d, 32); 3574 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3575 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3576 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3577 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3578 mbedtls_mpi_free(&x); 3579 #endif 3580 sm_have_ec_keypair = 1; 3581 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3582 #endif 3583 } 3584 3585 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3586 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3587 if (!hci_con) return NULL; 3588 return &hci_con->sm_connection; 3589 } 3590 3591 // @returns 0 if not encrypted, 7-16 otherwise 3592 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3593 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3594 if (!sm_conn) return 0; // wrong connection 3595 if (!sm_conn->sm_connection_encrypted) return 0; 3596 return sm_conn->sm_actual_encryption_key_size; 3597 } 3598 3599 int sm_authenticated(hci_con_handle_t con_handle){ 3600 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3601 if (!sm_conn) return 0; // wrong connection 3602 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3603 return sm_conn->sm_connection_authenticated; 3604 } 3605 3606 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3607 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3608 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3609 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3610 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3611 return sm_conn->sm_connection_authorization_state; 3612 } 3613 3614 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3615 switch (sm_conn->sm_engine_state){ 3616 case SM_GENERAL_IDLE: 3617 case SM_RESPONDER_IDLE: 3618 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3619 sm_run(); 3620 break; 3621 default: 3622 break; 3623 } 3624 } 3625 3626 /** 3627 * @brief Trigger Security Request 3628 */ 3629 void sm_send_security_request(hci_con_handle_t con_handle){ 3630 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3631 if (!sm_conn) return; 3632 sm_send_security_request_for_connection(sm_conn); 3633 } 3634 3635 // request pairing 3636 void sm_request_pairing(hci_con_handle_t con_handle){ 3637 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3638 if (!sm_conn) return; // wrong connection 3639 3640 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3641 if (sm_conn->sm_role){ 3642 sm_send_security_request_for_connection(sm_conn); 3643 } else { 3644 // used as a trigger to start central/master/initiator security procedures 3645 uint16_t ediv; 3646 sm_key_t ltk; 3647 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3648 switch (sm_conn->sm_irk_lookup_state){ 3649 case IRK_LOOKUP_FAILED: 3650 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3651 break; 3652 case IRK_LOOKUP_SUCCEEDED: 3653 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3654 if (!sm_is_null_key(ltk) || ediv){ 3655 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3656 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3657 } else { 3658 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3659 } 3660 break; 3661 default: 3662 sm_conn->sm_bonding_requested = 1; 3663 break; 3664 } 3665 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3666 sm_conn->sm_bonding_requested = 1; 3667 } 3668 } 3669 sm_run(); 3670 } 3671 3672 // called by client app on authorization request 3673 void sm_authorization_decline(hci_con_handle_t con_handle){ 3674 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3675 if (!sm_conn) return; // wrong connection 3676 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3677 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3678 } 3679 3680 void sm_authorization_grant(hci_con_handle_t con_handle){ 3681 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3682 if (!sm_conn) return; // wrong connection 3683 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3684 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3685 } 3686 3687 // GAP Bonding API 3688 3689 void sm_bonding_decline(hci_con_handle_t con_handle){ 3690 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3691 if (!sm_conn) return; // wrong connection 3692 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3693 3694 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3695 switch (setup->sm_stk_generation_method){ 3696 case PK_RESP_INPUT: 3697 case PK_INIT_INPUT: 3698 case OK_BOTH_INPUT: 3699 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3700 break; 3701 case NK_BOTH_INPUT: 3702 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3703 break; 3704 case JUST_WORKS: 3705 case OOB: 3706 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3707 break; 3708 } 3709 } 3710 sm_run(); 3711 } 3712 3713 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3714 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3715 if (!sm_conn) return; // wrong connection 3716 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3717 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3718 if (setup->sm_use_secure_connections){ 3719 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3720 } else { 3721 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3722 } 3723 } 3724 3725 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3726 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3727 sm_sc_prepare_dhkey_check(sm_conn); 3728 } 3729 #endif 3730 3731 sm_run(); 3732 } 3733 3734 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3735 // for now, it's the same 3736 sm_just_works_confirm(con_handle); 3737 } 3738 3739 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3740 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3741 if (!sm_conn) return; // wrong connection 3742 sm_reset_tk(); 3743 big_endian_store_32(setup->sm_tk, 12, passkey); 3744 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3745 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3746 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3747 } 3748 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3749 memcpy(setup->sm_ra, setup->sm_tk, 16); 3750 memcpy(setup->sm_rb, setup->sm_tk, 16); 3751 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3752 sm_sc_start_calculating_local_confirm(sm_conn); 3753 } 3754 #endif 3755 sm_run(); 3756 } 3757 3758 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3759 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3760 if (!sm_conn) return; // wrong connection 3761 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3762 setup->sm_keypress_notification = action; 3763 sm_run(); 3764 } 3765 3766 /** 3767 * @brief Identify device in LE Device DB 3768 * @param handle 3769 * @returns index from le_device_db or -1 if not found/identified 3770 */ 3771 int sm_le_device_index(hci_con_handle_t con_handle ){ 3772 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3773 if (!sm_conn) return -1; 3774 return sm_conn->sm_le_db_index; 3775 } 3776 3777 // GAP LE API 3778 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3779 gap_random_address_update_stop(); 3780 gap_random_adress_type = random_address_type; 3781 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3782 gap_random_address_update_start(); 3783 gap_random_address_trigger(); 3784 } 3785 3786 gap_random_address_type_t gap_random_address_get_mode(void){ 3787 return gap_random_adress_type; 3788 } 3789 3790 void gap_random_address_set_update_period(int period_ms){ 3791 gap_random_adress_update_period = period_ms; 3792 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3793 gap_random_address_update_stop(); 3794 gap_random_address_update_start(); 3795 } 3796 3797 void gap_random_address_set(bd_addr_t addr){ 3798 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3799 memcpy(sm_random_address, addr, 6); 3800 rau_state = RAU_SET_ADDRESS; 3801 sm_run(); 3802 } 3803 3804 /* 3805 * @brief Set Advertisement Paramters 3806 * @param adv_int_min 3807 * @param adv_int_max 3808 * @param adv_type 3809 * @param direct_address_type 3810 * @param direct_address 3811 * @param channel_map 3812 * @param filter_policy 3813 * 3814 * @note own_address_type is used from gap_random_address_set_mode 3815 */ 3816 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3817 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3818 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3819 direct_address_typ, direct_address, channel_map, filter_policy); 3820 } 3821 3822