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 "hci_dump.h" 52 #include "l2cap.h" 53 54 #ifdef ENABLE_LE_SECURE_CONNECTIONS 55 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 56 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 57 #else 58 #define USE_MBEDTLS_FOR_ECDH 59 #endif 60 #endif 61 62 63 // Software ECDH implementation provided by mbedtls 64 #ifdef USE_MBEDTLS_FOR_ECDH 65 #include "mbedtls/config.h" 66 #include "mbedtls/platform.h" 67 #include "mbedtls/ecp.h" 68 #include "sm_mbedtls_allocator.h" 69 #endif 70 71 // 72 // SM internal types and globals 73 // 74 75 typedef enum { 76 DKG_W4_WORKING, 77 DKG_CALC_IRK, 78 DKG_W4_IRK, 79 DKG_CALC_DHK, 80 DKG_W4_DHK, 81 DKG_READY 82 } derived_key_generation_t; 83 84 typedef enum { 85 RAU_W4_WORKING, 86 RAU_IDLE, 87 RAU_GET_RANDOM, 88 RAU_W4_RANDOM, 89 RAU_GET_ENC, 90 RAU_W4_ENC, 91 RAU_SET_ADDRESS, 92 } random_address_update_t; 93 94 typedef enum { 95 CMAC_IDLE, 96 CMAC_CALC_SUBKEYS, 97 CMAC_W4_SUBKEYS, 98 CMAC_CALC_MI, 99 CMAC_W4_MI, 100 CMAC_CALC_MLAST, 101 CMAC_W4_MLAST 102 } cmac_state_t; 103 104 typedef enum { 105 JUST_WORKS, 106 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 107 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 108 OK_BOTH_INPUT, // Only input on both, both input PK 109 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 110 OOB // OOB available on both sides 111 } stk_generation_method_t; 112 113 typedef enum { 114 SM_USER_RESPONSE_IDLE, 115 SM_USER_RESPONSE_PENDING, 116 SM_USER_RESPONSE_CONFIRM, 117 SM_USER_RESPONSE_PASSKEY, 118 SM_USER_RESPONSE_DECLINE 119 } sm_user_response_t; 120 121 typedef enum { 122 SM_AES128_IDLE, 123 SM_AES128_ACTIVE 124 } sm_aes128_state_t; 125 126 typedef enum { 127 ADDRESS_RESOLUTION_IDLE, 128 ADDRESS_RESOLUTION_GENERAL, 129 ADDRESS_RESOLUTION_FOR_CONNECTION, 130 } address_resolution_mode_t; 131 132 typedef enum { 133 ADDRESS_RESOLUTION_SUCEEDED, 134 ADDRESS_RESOLUTION_FAILED, 135 } address_resolution_event_t; 136 137 typedef enum { 138 EC_KEY_GENERATION_IDLE, 139 EC_KEY_GENERATION_ACTIVE, 140 EC_KEY_GENERATION_W4_KEY, 141 EC_KEY_GENERATION_DONE, 142 } ec_key_generation_state_t; 143 144 typedef enum { 145 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 146 } sm_state_var_t; 147 148 // 149 // GLOBAL DATA 150 // 151 152 static uint8_t test_use_fixed_local_csrk; 153 154 // configuration 155 static uint8_t sm_accepted_stk_generation_methods; 156 static uint8_t sm_max_encryption_key_size; 157 static uint8_t sm_min_encryption_key_size; 158 static uint8_t sm_auth_req = 0; 159 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 160 static uint8_t sm_slave_request_security; 161 #ifdef ENABLE_LE_SECURE_CONNECTIONS 162 static uint8_t sm_have_ec_keypair; 163 #endif 164 165 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 166 static sm_key_t sm_persistent_er; 167 static sm_key_t sm_persistent_ir; 168 169 // derived from sm_persistent_ir 170 static sm_key_t sm_persistent_dhk; 171 static sm_key_t sm_persistent_irk; 172 static uint8_t sm_persistent_irk_ready = 0; // used for testing 173 static derived_key_generation_t dkg_state; 174 175 // derived from sm_persistent_er 176 // .. 177 178 // random address update 179 static random_address_update_t rau_state; 180 static bd_addr_t sm_random_address; 181 182 // CMAC Calculation: General 183 static cmac_state_t sm_cmac_state; 184 static uint16_t sm_cmac_message_len; 185 static sm_key_t sm_cmac_k; 186 static sm_key_t sm_cmac_x; 187 static sm_key_t sm_cmac_m_last; 188 static uint8_t sm_cmac_block_current; 189 static uint8_t sm_cmac_block_count; 190 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 191 static void (*sm_cmac_done_handler)(uint8_t * hash); 192 193 // CMAC for ATT Signed Writes 194 static uint8_t sm_cmac_header[3]; 195 static const uint8_t * sm_cmac_message; 196 static uint8_t sm_cmac_sign_counter[4]; 197 198 // CMAC for Secure Connection functions 199 #ifdef ENABLE_LE_SECURE_CONNECTIONS 200 static sm_connection_t * sm_cmac_connection; 201 static uint8_t sm_cmac_sc_buffer[80]; 202 #endif 203 204 // resolvable private address lookup / CSRK calculation 205 static int sm_address_resolution_test; 206 static int sm_address_resolution_ah_calculation_active; 207 static uint8_t sm_address_resolution_addr_type; 208 static bd_addr_t sm_address_resolution_address; 209 static void * sm_address_resolution_context; 210 static address_resolution_mode_t sm_address_resolution_mode; 211 static btstack_linked_list_t sm_address_resolution_general_queue; 212 213 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 214 static sm_aes128_state_t sm_aes128_state; 215 static void * sm_aes128_context; 216 217 // random engine. store context (ususally sm_connection_t) 218 static void * sm_random_context; 219 220 // to receive hci events 221 static btstack_packet_callback_registration_t hci_event_callback_registration; 222 223 /* to dispatch sm event */ 224 static btstack_linked_list_t sm_event_handlers; 225 226 // LE Secure Connections 227 #ifdef ENABLE_LE_SECURE_CONNECTIONS 228 static ec_key_generation_state_t ec_key_generation_state; 229 static uint8_t ec_d[32]; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 #endif 233 234 // Software ECDH implementation provided by mbedtls 235 #ifdef USE_MBEDTLS_FOR_ECDH 236 // group is always valid 237 static mbedtls_ecp_group mbedtls_ec_group; 238 #ifndef HAVE_MALLOC 239 // COMP Method with Window 2 240 // 1300 bytes with 23 allocations 241 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 242 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 243 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 244 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 245 #endif 246 #endif 247 248 // 249 // Volume 3, Part H, Chapter 24 250 // "Security shall be initiated by the Security Manager in the device in the master role. 251 // The device in the slave role shall be the responding device." 252 // -> master := initiator, slave := responder 253 // 254 255 // data needed for security setup 256 typedef struct sm_setup_context { 257 258 btstack_timer_source_t sm_timeout; 259 260 // used in all phases 261 uint8_t sm_pairing_failed_reason; 262 263 // user response, (Phase 1 and/or 2) 264 uint8_t sm_user_response; 265 uint8_t sm_keypress_notification; 266 267 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 268 int sm_key_distribution_send_set; 269 int sm_key_distribution_received_set; 270 271 // Phase 2 (Pairing over SMP) 272 stk_generation_method_t sm_stk_generation_method; 273 sm_key_t sm_tk; 274 uint8_t sm_use_secure_connections; 275 276 sm_key_t sm_c1_t3_value; // c1 calculation 277 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 278 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 279 sm_key_t sm_local_random; 280 sm_key_t sm_local_confirm; 281 sm_key_t sm_peer_random; 282 sm_key_t sm_peer_confirm; 283 uint8_t sm_m_addr_type; // address and type can be removed 284 uint8_t sm_s_addr_type; // '' 285 bd_addr_t sm_m_address; // '' 286 bd_addr_t sm_s_address; // '' 287 sm_key_t sm_ltk; 288 289 uint8_t sm_state_vars; 290 #ifdef ENABLE_LE_SECURE_CONNECTIONS 291 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 292 uint8_t sm_peer_qy[32]; // '' 293 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 294 sm_key_t sm_local_nonce; // might be combined with sm_local_random 295 sm_key_t sm_peer_dhkey_check; 296 sm_key_t sm_local_dhkey_check; 297 sm_key_t sm_ra; 298 sm_key_t sm_rb; 299 sm_key_t sm_t; // used for f5 and h6 300 sm_key_t sm_mackey; 301 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 302 #endif 303 304 // Phase 3 305 306 // key distribution, we generate 307 uint16_t sm_local_y; 308 uint16_t sm_local_div; 309 uint16_t sm_local_ediv; 310 uint8_t sm_local_rand[8]; 311 sm_key_t sm_local_ltk; 312 sm_key_t sm_local_csrk; 313 sm_key_t sm_local_irk; 314 // sm_local_address/addr_type not needed 315 316 // key distribution, received from peer 317 uint16_t sm_peer_y; 318 uint16_t sm_peer_div; 319 uint16_t sm_peer_ediv; 320 uint8_t sm_peer_rand[8]; 321 sm_key_t sm_peer_ltk; 322 sm_key_t sm_peer_irk; 323 sm_key_t sm_peer_csrk; 324 uint8_t sm_peer_addr_type; 325 bd_addr_t sm_peer_address; 326 327 } sm_setup_context_t; 328 329 // 330 static sm_setup_context_t the_setup; 331 static sm_setup_context_t * setup = &the_setup; 332 333 // active connection - the one for which the_setup is used for 334 static uint16_t sm_active_connection = 0; 335 336 // @returns 1 if oob data is available 337 // stores oob data in provided 16 byte buffer if not null 338 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 339 340 // horizontal: initiator capabilities 341 // vertial: responder capabilities 342 static const stk_generation_method_t stk_generation_method [5] [5] = { 343 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 344 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 345 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 346 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 347 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 348 }; 349 350 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 351 #ifdef ENABLE_LE_SECURE_CONNECTIONS 352 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 353 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 354 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 355 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 356 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 357 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 358 }; 359 #endif 360 361 static void sm_run(void); 362 static void sm_done_for_handle(hci_con_handle_t con_handle); 363 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 364 static inline int sm_calc_actual_encryption_key_size(int other); 365 static int sm_validate_stk_generation_method(void); 366 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 367 368 static void log_info_hex16(const char * name, uint16_t value){ 369 log_info("%-6s 0x%04x", name, value); 370 } 371 372 // @returns 1 if all bytes are 0 373 static int sm_is_null(uint8_t * data, int size){ 374 int i; 375 for (i=0; i < size ; i++){ 376 if (data[i]) return 0; 377 } 378 return 1; 379 } 380 381 static int sm_is_null_random(uint8_t random[8]){ 382 return sm_is_null(random, 8); 383 } 384 385 static int sm_is_null_key(uint8_t * key){ 386 return sm_is_null(key, 16); 387 } 388 389 // Key utils 390 static void sm_reset_tk(void){ 391 int i; 392 for (i=0;i<16;i++){ 393 setup->sm_tk[i] = 0; 394 } 395 } 396 397 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 398 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 399 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 400 int i; 401 for (i = max_encryption_size ; i < 16 ; i++){ 402 key[15-i] = 0; 403 } 404 } 405 406 // SMP Timeout implementation 407 408 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 409 // the Security Manager Timer shall be reset and started. 410 // 411 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 412 // 413 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 414 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 415 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 416 // established. 417 418 static void sm_timeout_handler(btstack_timer_source_t * timer){ 419 log_info("SM timeout"); 420 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 421 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 422 sm_done_for_handle(sm_conn->sm_handle); 423 424 // trigger handling of next ready connection 425 sm_run(); 426 } 427 static void sm_timeout_start(sm_connection_t * sm_conn){ 428 btstack_run_loop_remove_timer(&setup->sm_timeout); 429 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 430 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 431 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 432 btstack_run_loop_add_timer(&setup->sm_timeout); 433 } 434 static void sm_timeout_stop(void){ 435 btstack_run_loop_remove_timer(&setup->sm_timeout); 436 } 437 static void sm_timeout_reset(sm_connection_t * sm_conn){ 438 sm_timeout_stop(); 439 sm_timeout_start(sm_conn); 440 } 441 442 // end of sm timeout 443 444 // GAP Random Address updates 445 static gap_random_address_type_t gap_random_adress_type; 446 static btstack_timer_source_t gap_random_address_update_timer; 447 static uint32_t gap_random_adress_update_period; 448 449 static void gap_random_address_trigger(void){ 450 if (rau_state != RAU_IDLE) return; 451 log_info("gap_random_address_trigger"); 452 rau_state = RAU_GET_RANDOM; 453 sm_run(); 454 } 455 456 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 457 UNUSED(timer); 458 459 log_info("GAP Random Address Update due"); 460 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 461 btstack_run_loop_add_timer(&gap_random_address_update_timer); 462 gap_random_address_trigger(); 463 } 464 465 static void gap_random_address_update_start(void){ 466 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 467 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 468 btstack_run_loop_add_timer(&gap_random_address_update_timer); 469 } 470 471 static void gap_random_address_update_stop(void){ 472 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 473 } 474 475 476 static void sm_random_start(void * context){ 477 sm_random_context = context; 478 hci_send_cmd(&hci_le_rand); 479 } 480 481 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 482 // context is made availabe to aes128 result handler by this 483 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 484 sm_aes128_state = SM_AES128_ACTIVE; 485 sm_key_t key_flipped, plaintext_flipped; 486 reverse_128(key, key_flipped); 487 reverse_128(plaintext, plaintext_flipped); 488 sm_aes128_context = context; 489 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 490 } 491 492 // ah(k,r) helper 493 // r = padding || r 494 // r - 24 bit value 495 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 496 // r'= padding || r 497 memset(r_prime, 0, 16); 498 memcpy(&r_prime[13], r, 3); 499 } 500 501 // d1 helper 502 // d' = padding || r || d 503 // d,r - 16 bit values 504 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 505 // d'= padding || r || d 506 memset(d1_prime, 0, 16); 507 big_endian_store_16(d1_prime, 12, r); 508 big_endian_store_16(d1_prime, 14, d); 509 } 510 511 // dm helper 512 // r’ = padding || r 513 // r - 64 bit value 514 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ 515 memset(r_prime, 0, 16); 516 memcpy(&r_prime[8], r, 8); 517 } 518 519 // calculate arguments for first AES128 operation in C1 function 520 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 521 522 // p1 = pres || preq || rat’ || iat’ 523 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 524 // cant octet of pres becomes the most significant octet of p1. 525 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 526 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 527 // p1 is 0x05000800000302070710000001010001." 528 529 sm_key_t p1; 530 reverse_56(pres, &p1[0]); 531 reverse_56(preq, &p1[7]); 532 p1[14] = rat; 533 p1[15] = iat; 534 log_info_key("p1", p1); 535 log_info_key("r", r); 536 537 // t1 = r xor p1 538 int i; 539 for (i=0;i<16;i++){ 540 t1[i] = r[i] ^ p1[i]; 541 } 542 log_info_key("t1", t1); 543 } 544 545 // calculate arguments for second AES128 operation in C1 function 546 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 547 // p2 = padding || ia || ra 548 // "The least significant octet of ra becomes the least significant octet of p2 and 549 // the most significant octet of padding becomes the most significant octet of p2. 550 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 551 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 552 553 sm_key_t p2; 554 memset(p2, 0, 16); 555 memcpy(&p2[4], ia, 6); 556 memcpy(&p2[10], ra, 6); 557 log_info_key("p2", p2); 558 559 // c1 = e(k, t2_xor_p2) 560 int i; 561 for (i=0;i<16;i++){ 562 t3[i] = t2[i] ^ p2[i]; 563 } 564 log_info_key("t3", t3); 565 } 566 567 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 568 log_info_key("r1", r1); 569 log_info_key("r2", r2); 570 memcpy(&r_prime[8], &r2[8], 8); 571 memcpy(&r_prime[0], &r1[8], 8); 572 } 573 574 #ifdef ENABLE_LE_SECURE_CONNECTIONS 575 // Software implementations of crypto toolbox for LE Secure Connection 576 // TODO: replace with code to use AES Engine of HCI Controller 577 typedef uint8_t sm_key24_t[3]; 578 typedef uint8_t sm_key56_t[7]; 579 typedef uint8_t sm_key256_t[32]; 580 581 #if 0 582 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 583 uint32_t rk[RKLENGTH(KEYBITS)]; 584 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 585 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 586 } 587 588 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 589 memcpy(k1, k0, 16); 590 sm_shift_left_by_one_bit_inplace(16, k1); 591 if (k0[0] & 0x80){ 592 k1[15] ^= 0x87; 593 } 594 memcpy(k2, k1, 16); 595 sm_shift_left_by_one_bit_inplace(16, k2); 596 if (k1[0] & 0x80){ 597 k2[15] ^= 0x87; 598 } 599 } 600 601 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 602 sm_key_t k0, k1, k2, zero; 603 memset(zero, 0, 16); 604 605 aes128_calc_cyphertext(key, zero, k0); 606 calc_subkeys(k0, k1, k2); 607 608 int cmac_block_count = (cmac_message_len + 15) / 16; 609 610 // step 3: .. 611 if (cmac_block_count==0){ 612 cmac_block_count = 1; 613 } 614 615 // step 4: set m_last 616 sm_key_t cmac_m_last; 617 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 618 int i; 619 if (sm_cmac_last_block_complete){ 620 for (i=0;i<16;i++){ 621 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 622 } 623 } else { 624 int valid_octets_in_last_block = cmac_message_len & 0x0f; 625 for (i=0;i<16;i++){ 626 if (i < valid_octets_in_last_block){ 627 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 628 continue; 629 } 630 if (i == valid_octets_in_last_block){ 631 cmac_m_last[i] = 0x80 ^ k2[i]; 632 continue; 633 } 634 cmac_m_last[i] = k2[i]; 635 } 636 } 637 638 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 639 // LOG_KEY(cmac_m_last); 640 641 // Step 5 642 sm_key_t cmac_x; 643 memset(cmac_x, 0, 16); 644 645 // Step 6 646 sm_key_t sm_cmac_y; 647 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 648 for (i=0;i<16;i++){ 649 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 650 } 651 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 652 } 653 for (i=0;i<16;i++){ 654 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 655 } 656 657 // Step 7 658 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 659 } 660 #endif 661 #endif 662 663 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){ 664 event[0] = type; 665 event[1] = event_size - 2; 666 little_endian_store_16(event, 2, con_handle); 667 event[4] = addr_type; 668 reverse_bd_addr(address, &event[5]); 669 } 670 671 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 672 UNUSED(channel); 673 674 // log event 675 hci_dump_packet(packet_type, 1, packet, size); 676 // dispatch to all event handlers 677 btstack_linked_list_iterator_t it; 678 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 679 while (btstack_linked_list_iterator_has_next(&it)){ 680 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 681 entry->callback(packet_type, 0, packet, size); 682 } 683 } 684 685 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 686 uint8_t event[11]; 687 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 688 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 689 } 690 691 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){ 692 uint8_t event[15]; 693 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 694 little_endian_store_32(event, 11, passkey); 695 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 696 } 697 698 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){ 699 // fetch addr and addr type from db 700 bd_addr_t identity_address; 701 int identity_address_type; 702 le_device_db_info(index, &identity_address_type, identity_address, NULL); 703 704 uint8_t event[19]; 705 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 706 event[11] = identity_address_type; 707 reverse_bd_addr(identity_address, &event[12]); 708 event[18] = index; 709 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 710 } 711 712 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){ 713 714 uint8_t event[18]; 715 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 716 event[11] = result; 717 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 718 } 719 720 // decide on stk generation based on 721 // - pairing request 722 // - io capabilities 723 // - OOB data availability 724 static void sm_setup_tk(void){ 725 726 // default: just works 727 setup->sm_stk_generation_method = JUST_WORKS; 728 729 #ifdef ENABLE_LE_SECURE_CONNECTIONS 730 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 731 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 732 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 733 memset(setup->sm_ra, 0, 16); 734 memset(setup->sm_rb, 0, 16); 735 #else 736 setup->sm_use_secure_connections = 0; 737 #endif 738 739 // If both devices have not set the MITM option in the Authentication Requirements 740 // Flags, then the IO capabilities shall be ignored and the Just Works association 741 // model shall be used. 742 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 743 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 744 log_info("SM: MITM not required by both -> JUST WORKS"); 745 return; 746 } 747 748 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 749 750 // If both devices have out of band authentication data, then the Authentication 751 // Requirements Flags shall be ignored when selecting the pairing method and the 752 // Out of Band pairing method shall be used. 753 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 754 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 755 log_info("SM: have OOB data"); 756 log_info_key("OOB", setup->sm_tk); 757 setup->sm_stk_generation_method = OOB; 758 return; 759 } 760 761 // Reset TK as it has been setup in sm_init_setup 762 sm_reset_tk(); 763 764 // Also use just works if unknown io capabilites 765 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)){ 766 return; 767 } 768 769 // Otherwise the IO capabilities of the devices shall be used to determine the 770 // pairing method as defined in Table 2.4. 771 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 772 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 773 774 #ifdef ENABLE_LE_SECURE_CONNECTIONS 775 // table not define by default 776 if (setup->sm_use_secure_connections){ 777 generation_method = stk_generation_method_with_secure_connection; 778 } 779 #endif 780 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)]; 781 782 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 783 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); 784 } 785 786 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 787 int flags = 0; 788 if (key_set & SM_KEYDIST_ENC_KEY){ 789 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 790 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 791 } 792 if (key_set & SM_KEYDIST_ID_KEY){ 793 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 794 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 795 } 796 if (key_set & SM_KEYDIST_SIGN){ 797 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 798 } 799 return flags; 800 } 801 802 static void sm_setup_key_distribution(uint8_t key_set){ 803 setup->sm_key_distribution_received_set = 0; 804 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 805 } 806 807 // CSRK Key Lookup 808 809 810 static int sm_address_resolution_idle(void){ 811 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 812 } 813 814 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){ 815 memcpy(sm_address_resolution_address, addr, 6); 816 sm_address_resolution_addr_type = addr_type; 817 sm_address_resolution_test = 0; 818 sm_address_resolution_mode = mode; 819 sm_address_resolution_context = context; 820 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 821 } 822 823 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 824 // check if already in list 825 btstack_linked_list_iterator_t it; 826 sm_lookup_entry_t * entry; 827 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 828 while(btstack_linked_list_iterator_has_next(&it)){ 829 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 830 if (entry->address_type != address_type) continue; 831 if (memcmp(entry->address, address, 6)) continue; 832 // already in list 833 return BTSTACK_BUSY; 834 } 835 entry = btstack_memory_sm_lookup_entry_get(); 836 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 837 entry->address_type = (bd_addr_type_t) address_type; 838 memcpy(entry->address, address, 6); 839 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 840 sm_run(); 841 return 0; 842 } 843 844 // CMAC Implementation using AES128 engine 845 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 846 int i; 847 int carry = 0; 848 for (i=len-1; i >= 0 ; i--){ 849 int new_carry = data[i] >> 7; 850 data[i] = data[i] << 1 | carry; 851 carry = new_carry; 852 } 853 } 854 855 // 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 856 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 857 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 858 } 859 static inline void dkg_next_state(void){ 860 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 861 } 862 static inline void rau_next_state(void){ 863 rau_state = (random_address_update_t) (((int)rau_state) + 1); 864 } 865 866 // CMAC calculation using AES Engine 867 868 static inline void sm_cmac_next_state(void){ 869 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 870 } 871 872 static int sm_cmac_last_block_complete(void){ 873 if (sm_cmac_message_len == 0) return 0; 874 return (sm_cmac_message_len & 0x0f) == 0; 875 } 876 877 int sm_cmac_ready(void){ 878 return sm_cmac_state == CMAC_IDLE; 879 } 880 881 // generic cmac calculation 882 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])){ 883 // Generalized CMAC 884 memcpy(sm_cmac_k, key, 16); 885 memset(sm_cmac_x, 0, 16); 886 sm_cmac_block_current = 0; 887 sm_cmac_message_len = message_len; 888 sm_cmac_done_handler = done_callback; 889 sm_cmac_get_byte = get_byte_callback; 890 891 // step 2: n := ceil(len/const_Bsize); 892 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 893 894 // step 3: .. 895 if (sm_cmac_block_count==0){ 896 sm_cmac_block_count = 1; 897 } 898 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 899 900 // first, we need to compute l for k1, k2, and m_last 901 sm_cmac_state = CMAC_CALC_SUBKEYS; 902 903 // let's go 904 sm_run(); 905 } 906 907 // cmac for ATT Message signing 908 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 909 if (offset >= sm_cmac_message_len) { 910 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 911 return 0; 912 } 913 914 offset = sm_cmac_message_len - 1 - offset; 915 916 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 917 if (offset < 3){ 918 return sm_cmac_header[offset]; 919 } 920 int actual_message_len_incl_header = sm_cmac_message_len - 4; 921 if (offset < actual_message_len_incl_header){ 922 return sm_cmac_message[offset - 3]; 923 } 924 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 925 } 926 927 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)){ 928 // ATT Message Signing 929 sm_cmac_header[0] = opcode; 930 little_endian_store_16(sm_cmac_header, 1, con_handle); 931 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 932 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 933 sm_cmac_message = message; 934 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 935 } 936 937 938 static void sm_cmac_handle_aes_engine_ready(void){ 939 switch (sm_cmac_state){ 940 case CMAC_CALC_SUBKEYS: { 941 sm_key_t const_zero; 942 memset(const_zero, 0, 16); 943 sm_cmac_next_state(); 944 sm_aes128_start(sm_cmac_k, const_zero, NULL); 945 break; 946 } 947 case CMAC_CALC_MI: { 948 int j; 949 sm_key_t y; 950 for (j=0;j<16;j++){ 951 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 952 } 953 sm_cmac_block_current++; 954 sm_cmac_next_state(); 955 sm_aes128_start(sm_cmac_k, y, NULL); 956 break; 957 } 958 case CMAC_CALC_MLAST: { 959 int i; 960 sm_key_t y; 961 for (i=0;i<16;i++){ 962 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 963 } 964 log_info_key("Y", y); 965 sm_cmac_block_current++; 966 sm_cmac_next_state(); 967 sm_aes128_start(sm_cmac_k, y, NULL); 968 break; 969 } 970 default: 971 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 972 break; 973 } 974 } 975 976 static void sm_cmac_handle_encryption_result(sm_key_t data){ 977 switch (sm_cmac_state){ 978 case CMAC_W4_SUBKEYS: { 979 sm_key_t k1; 980 memcpy(k1, data, 16); 981 sm_shift_left_by_one_bit_inplace(16, k1); 982 if (data[0] & 0x80){ 983 k1[15] ^= 0x87; 984 } 985 sm_key_t k2; 986 memcpy(k2, k1, 16); 987 sm_shift_left_by_one_bit_inplace(16, k2); 988 if (k1[0] & 0x80){ 989 k2[15] ^= 0x87; 990 } 991 992 log_info_key("k", sm_cmac_k); 993 log_info_key("k1", k1); 994 log_info_key("k2", k2); 995 996 // step 4: set m_last 997 int i; 998 if (sm_cmac_last_block_complete()){ 999 for (i=0;i<16;i++){ 1000 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1001 } 1002 } else { 1003 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1004 for (i=0;i<16;i++){ 1005 if (i < valid_octets_in_last_block){ 1006 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1007 continue; 1008 } 1009 if (i == valid_octets_in_last_block){ 1010 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1011 continue; 1012 } 1013 sm_cmac_m_last[i] = k2[i]; 1014 } 1015 } 1016 1017 // next 1018 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1019 break; 1020 } 1021 case CMAC_W4_MI: 1022 memcpy(sm_cmac_x, data, 16); 1023 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1024 break; 1025 case CMAC_W4_MLAST: 1026 // done 1027 log_info("Setting CMAC Engine to IDLE"); 1028 sm_cmac_state = CMAC_IDLE; 1029 log_info_key("CMAC", data); 1030 sm_cmac_done_handler(data); 1031 break; 1032 default: 1033 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1034 break; 1035 } 1036 } 1037 1038 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1039 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1040 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1041 switch (setup->sm_stk_generation_method){ 1042 case PK_RESP_INPUT: 1043 if (sm_conn->sm_role){ 1044 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1045 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1046 } else { 1047 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1048 } 1049 break; 1050 case PK_INIT_INPUT: 1051 if (sm_conn->sm_role){ 1052 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)); 1053 } else { 1054 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1055 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1056 } 1057 break; 1058 case OK_BOTH_INPUT: 1059 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1060 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1061 break; 1062 case NK_BOTH_INPUT: 1063 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1064 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)); 1065 break; 1066 case JUST_WORKS: 1067 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1068 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1069 break; 1070 case OOB: 1071 // client already provided OOB data, let's skip notification. 1072 break; 1073 } 1074 } 1075 1076 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1077 int recv_flags; 1078 if (sm_conn->sm_role){ 1079 // slave / responder 1080 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1081 } else { 1082 // master / initiator 1083 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1084 } 1085 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1086 return recv_flags == setup->sm_key_distribution_received_set; 1087 } 1088 1089 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1090 if (sm_active_connection == con_handle){ 1091 sm_timeout_stop(); 1092 sm_active_connection = 0; 1093 log_info("sm: connection 0x%x released setup context", con_handle); 1094 } 1095 } 1096 1097 static int sm_key_distribution_flags_for_auth_req(void){ 1098 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1099 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1100 // encryption information only if bonding requested 1101 flags |= SM_KEYDIST_ENC_KEY; 1102 } 1103 return flags; 1104 } 1105 1106 static void sm_reset_setup(void){ 1107 // fill in sm setup 1108 setup->sm_state_vars = 0; 1109 setup->sm_keypress_notification = 0xff; 1110 sm_reset_tk(); 1111 } 1112 1113 static void sm_init_setup(sm_connection_t * sm_conn){ 1114 1115 // fill in sm setup 1116 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1117 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1118 1119 // query client for OOB data 1120 int have_oob_data = 0; 1121 if (sm_get_oob_data) { 1122 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1123 } 1124 1125 sm_pairing_packet_t * local_packet; 1126 if (sm_conn->sm_role){ 1127 // slave 1128 local_packet = &setup->sm_s_pres; 1129 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1130 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1131 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1132 } else { 1133 // master 1134 local_packet = &setup->sm_m_preq; 1135 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1136 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1137 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1138 1139 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1140 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1141 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1142 } 1143 1144 uint8_t auth_req = sm_auth_req; 1145 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1146 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1147 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1148 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1149 } 1150 1151 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1152 1153 sm_pairing_packet_t * remote_packet; 1154 int remote_key_request; 1155 if (sm_conn->sm_role){ 1156 // slave / responder 1157 remote_packet = &setup->sm_m_preq; 1158 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1159 } else { 1160 // master / initiator 1161 remote_packet = &setup->sm_s_pres; 1162 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1163 } 1164 1165 // check key size 1166 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1167 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1168 1169 // decide on STK generation method 1170 sm_setup_tk(); 1171 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1172 1173 // check if STK generation method is acceptable by client 1174 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1175 1176 // identical to responder 1177 sm_setup_key_distribution(remote_key_request); 1178 1179 // JUST WORKS doens't provide authentication 1180 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1181 1182 return 0; 1183 } 1184 1185 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1186 1187 // cache and reset context 1188 int matched_device_id = sm_address_resolution_test; 1189 address_resolution_mode_t mode = sm_address_resolution_mode; 1190 void * context = sm_address_resolution_context; 1191 1192 // reset context 1193 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1194 sm_address_resolution_context = NULL; 1195 sm_address_resolution_test = -1; 1196 hci_con_handle_t con_handle = 0; 1197 1198 sm_connection_t * sm_connection; 1199 sm_key_t ltk; 1200 switch (mode){ 1201 case ADDRESS_RESOLUTION_GENERAL: 1202 break; 1203 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1204 sm_connection = (sm_connection_t *) context; 1205 con_handle = sm_connection->sm_handle; 1206 switch (event){ 1207 case ADDRESS_RESOLUTION_SUCEEDED: 1208 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1209 sm_connection->sm_le_db_index = matched_device_id; 1210 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1211 if (sm_connection->sm_role) break; 1212 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1213 sm_connection->sm_security_request_received = 0; 1214 sm_connection->sm_bonding_requested = 0; 1215 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1216 if (!sm_is_null_key(ltk)){ 1217 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1218 } else { 1219 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1220 } 1221 break; 1222 case ADDRESS_RESOLUTION_FAILED: 1223 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1224 if (sm_connection->sm_role) break; 1225 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1226 sm_connection->sm_security_request_received = 0; 1227 sm_connection->sm_bonding_requested = 0; 1228 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1229 break; 1230 } 1231 break; 1232 default: 1233 break; 1234 } 1235 1236 switch (event){ 1237 case ADDRESS_RESOLUTION_SUCEEDED: 1238 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1239 break; 1240 case ADDRESS_RESOLUTION_FAILED: 1241 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1242 break; 1243 } 1244 } 1245 1246 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1247 1248 int le_db_index = -1; 1249 1250 // lookup device based on IRK 1251 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1252 int i; 1253 for (i=0; i < le_device_db_count(); i++){ 1254 sm_key_t irk; 1255 bd_addr_t address; 1256 int address_type; 1257 le_device_db_info(i, &address_type, address, irk); 1258 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1259 log_info("sm: device found for IRK, updating"); 1260 le_db_index = i; 1261 break; 1262 } 1263 } 1264 } 1265 1266 // if not found, lookup via public address if possible 1267 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1268 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1269 int i; 1270 for (i=0; i < le_device_db_count(); i++){ 1271 bd_addr_t address; 1272 int address_type; 1273 le_device_db_info(i, &address_type, address, NULL); 1274 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1275 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1276 log_info("sm: device found for public address, updating"); 1277 le_db_index = i; 1278 break; 1279 } 1280 } 1281 } 1282 1283 // if not found, add to db 1284 if (le_db_index < 0) { 1285 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1286 } 1287 1288 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1289 1290 if (le_db_index >= 0){ 1291 1292 // store local CSRK 1293 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1294 log_info("sm: store local CSRK"); 1295 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1296 le_device_db_local_counter_set(le_db_index, 0); 1297 } 1298 1299 // store remote CSRK 1300 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1301 log_info("sm: store remote CSRK"); 1302 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1303 le_device_db_remote_counter_set(le_db_index, 0); 1304 } 1305 1306 // store encryption information for secure connections: LTK generated by ECDH 1307 if (setup->sm_use_secure_connections){ 1308 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1309 uint8_t zero_rand[8]; 1310 memset(zero_rand, 0, 8); 1311 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1312 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1313 } 1314 1315 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1316 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1317 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1318 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1319 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1320 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1321 1322 } 1323 } 1324 1325 // keep le_db_index 1326 sm_conn->sm_le_db_index = le_db_index; 1327 } 1328 1329 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1330 setup->sm_pairing_failed_reason = reason; 1331 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1332 } 1333 1334 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1335 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1336 } 1337 1338 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1339 1340 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1341 static int sm_passkey_used(stk_generation_method_t method); 1342 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1343 1344 static void sm_log_ec_keypair(void){ 1345 log_info("Elliptic curve: X"); 1346 log_info_hexdump(ec_qx,32); 1347 log_info("Elliptic curve: Y"); 1348 log_info_hexdump(ec_qy,32); 1349 } 1350 1351 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1352 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1353 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1354 } else { 1355 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1356 } 1357 } 1358 1359 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1360 if (sm_conn->sm_role){ 1361 // Responder 1362 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1363 } else { 1364 // Initiator role 1365 switch (setup->sm_stk_generation_method){ 1366 case JUST_WORKS: 1367 sm_sc_prepare_dhkey_check(sm_conn); 1368 break; 1369 1370 case NK_BOTH_INPUT: 1371 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1372 break; 1373 case PK_INIT_INPUT: 1374 case PK_RESP_INPUT: 1375 case OK_BOTH_INPUT: 1376 if (setup->sm_passkey_bit < 20) { 1377 sm_sc_start_calculating_local_confirm(sm_conn); 1378 } else { 1379 sm_sc_prepare_dhkey_check(sm_conn); 1380 } 1381 break; 1382 case OOB: 1383 // TODO: implement SC OOB 1384 break; 1385 } 1386 } 1387 } 1388 1389 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1390 return sm_cmac_sc_buffer[offset]; 1391 } 1392 1393 static void sm_sc_cmac_done(uint8_t * hash){ 1394 log_info("sm_sc_cmac_done: "); 1395 log_info_hexdump(hash, 16); 1396 1397 sm_connection_t * sm_conn = sm_cmac_connection; 1398 sm_cmac_connection = NULL; 1399 link_key_type_t link_key_type; 1400 1401 switch (sm_conn->sm_engine_state){ 1402 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1403 memcpy(setup->sm_local_confirm, hash, 16); 1404 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1405 break; 1406 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1407 // check 1408 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1409 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1410 break; 1411 } 1412 sm_sc_state_after_receiving_random(sm_conn); 1413 break; 1414 case SM_SC_W4_CALCULATE_G2: { 1415 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1416 big_endian_store_32(setup->sm_tk, 12, vab); 1417 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1418 sm_trigger_user_response(sm_conn); 1419 break; 1420 } 1421 case SM_SC_W4_CALCULATE_F5_SALT: 1422 memcpy(setup->sm_t, hash, 16); 1423 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1424 break; 1425 case SM_SC_W4_CALCULATE_F5_MACKEY: 1426 memcpy(setup->sm_mackey, hash, 16); 1427 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1428 break; 1429 case SM_SC_W4_CALCULATE_F5_LTK: 1430 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1431 // Errata Service Release to the Bluetooth Specification: ESR09 1432 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1433 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1434 memcpy(setup->sm_ltk, hash, 16); 1435 memcpy(setup->sm_local_ltk, hash, 16); 1436 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1437 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1438 break; 1439 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1440 memcpy(setup->sm_local_dhkey_check, hash, 16); 1441 if (sm_conn->sm_role){ 1442 // responder 1443 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1444 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1445 } else { 1446 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1447 } 1448 } else { 1449 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1450 } 1451 break; 1452 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1453 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1454 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1455 break; 1456 } 1457 if (sm_conn->sm_role){ 1458 // responder 1459 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1460 } else { 1461 // initiator 1462 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1463 } 1464 break; 1465 case SM_SC_W4_CALCULATE_H6_ILK: 1466 memcpy(setup->sm_t, hash, 16); 1467 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1468 break; 1469 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1470 reverse_128(hash, setup->sm_t); 1471 link_key_type = sm_conn->sm_connection_authenticated ? 1472 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1473 if (sm_conn->sm_role){ 1474 #ifdef ENABLE_CLASSIC 1475 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1476 #endif 1477 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1478 } else { 1479 #ifdef ENABLE_CLASSIC 1480 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1481 #endif 1482 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1483 } 1484 sm_done_for_handle(sm_conn->sm_handle); 1485 break; 1486 default: 1487 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1488 break; 1489 } 1490 sm_run(); 1491 } 1492 1493 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){ 1494 const uint16_t message_len = 65; 1495 sm_cmac_connection = sm_conn; 1496 memcpy(sm_cmac_sc_buffer, u, 32); 1497 memcpy(sm_cmac_sc_buffer+32, v, 32); 1498 sm_cmac_sc_buffer[64] = z; 1499 log_info("f4 key"); 1500 log_info_hexdump(x, 16); 1501 log_info("f4 message"); 1502 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1503 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1504 } 1505 1506 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1507 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1508 static const uint8_t f5_length[] = { 0x01, 0x00}; 1509 1510 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1511 #ifdef USE_MBEDTLS_FOR_ECDH 1512 // da * Pb 1513 mbedtls_mpi d; 1514 mbedtls_ecp_point Q; 1515 mbedtls_ecp_point DH; 1516 mbedtls_mpi_init(&d); 1517 mbedtls_ecp_point_init(&Q); 1518 mbedtls_ecp_point_init(&DH); 1519 mbedtls_mpi_read_binary(&d, ec_d, 32); 1520 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1521 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1522 mbedtls_mpi_lset(&Q.Z, 1); 1523 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1524 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1525 mbedtls_ecp_point_free(&DH); 1526 mbedtls_mpi_free(&d); 1527 mbedtls_ecp_point_free(&Q); 1528 #endif 1529 log_info("dhkey"); 1530 log_info_hexdump(dhkey, 32); 1531 } 1532 1533 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1534 // calculate DHKEY 1535 sm_key256_t dhkey; 1536 sm_sc_calculate_dhkey(dhkey); 1537 1538 // calculate salt for f5 1539 const uint16_t message_len = 32; 1540 sm_cmac_connection = sm_conn; 1541 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1542 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1543 } 1544 1545 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){ 1546 const uint16_t message_len = 53; 1547 sm_cmac_connection = sm_conn; 1548 1549 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1550 sm_cmac_sc_buffer[0] = 0; 1551 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1552 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1553 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1554 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1555 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1556 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1557 log_info("f5 key"); 1558 log_info_hexdump(t, 16); 1559 log_info("f5 message for MacKey"); 1560 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1561 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1562 } 1563 1564 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1565 sm_key56_t bd_addr_master, bd_addr_slave; 1566 bd_addr_master[0] = setup->sm_m_addr_type; 1567 bd_addr_slave[0] = setup->sm_s_addr_type; 1568 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1569 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1570 if (sm_conn->sm_role){ 1571 // responder 1572 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1573 } else { 1574 // initiator 1575 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1576 } 1577 } 1578 1579 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1580 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1581 const uint16_t message_len = 53; 1582 sm_cmac_connection = sm_conn; 1583 sm_cmac_sc_buffer[0] = 1; 1584 // 1..52 setup before 1585 log_info("f5 key"); 1586 log_info_hexdump(t, 16); 1587 log_info("f5 message for LTK"); 1588 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1589 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1590 } 1591 1592 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1593 f5_ltk(sm_conn, setup->sm_t); 1594 } 1595 1596 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){ 1597 const uint16_t message_len = 65; 1598 sm_cmac_connection = sm_conn; 1599 memcpy(sm_cmac_sc_buffer, n1, 16); 1600 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1601 memcpy(sm_cmac_sc_buffer+32, r, 16); 1602 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1603 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1604 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1605 log_info("f6 key"); 1606 log_info_hexdump(w, 16); 1607 log_info("f6 message"); 1608 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1609 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1610 } 1611 1612 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1613 // - U is 256 bits 1614 // - V is 256 bits 1615 // - X is 128 bits 1616 // - Y is 128 bits 1617 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){ 1618 const uint16_t message_len = 80; 1619 sm_cmac_connection = sm_conn; 1620 memcpy(sm_cmac_sc_buffer, u, 32); 1621 memcpy(sm_cmac_sc_buffer+32, v, 32); 1622 memcpy(sm_cmac_sc_buffer+64, y, 16); 1623 log_info("g2 key"); 1624 log_info_hexdump(x, 16); 1625 log_info("g2 message"); 1626 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1627 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1628 } 1629 1630 static void g2_calculate(sm_connection_t * sm_conn) { 1631 // calc Va if numeric comparison 1632 if (sm_conn->sm_role){ 1633 // responder 1634 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1635 } else { 1636 // initiator 1637 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1638 } 1639 } 1640 1641 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1642 uint8_t z = 0; 1643 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1644 // some form of passkey 1645 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1646 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1647 setup->sm_passkey_bit++; 1648 } 1649 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1650 } 1651 1652 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1653 uint8_t z = 0; 1654 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1655 // some form of passkey 1656 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1657 // sm_passkey_bit was increased before sending confirm value 1658 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1659 } 1660 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1661 } 1662 1663 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1664 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1665 } 1666 1667 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1668 // calculate DHKCheck 1669 sm_key56_t bd_addr_master, bd_addr_slave; 1670 bd_addr_master[0] = setup->sm_m_addr_type; 1671 bd_addr_slave[0] = setup->sm_s_addr_type; 1672 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1673 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1674 uint8_t iocap_a[3]; 1675 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1676 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1677 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1678 uint8_t iocap_b[3]; 1679 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1680 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1681 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1682 if (sm_conn->sm_role){ 1683 // responder 1684 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1685 } else { 1686 // initiator 1687 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); 1688 } 1689 } 1690 1691 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1692 // validate E = f6() 1693 sm_key56_t bd_addr_master, bd_addr_slave; 1694 bd_addr_master[0] = setup->sm_m_addr_type; 1695 bd_addr_slave[0] = setup->sm_s_addr_type; 1696 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1697 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1698 1699 uint8_t iocap_a[3]; 1700 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1701 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1702 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1703 uint8_t iocap_b[3]; 1704 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1705 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1706 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1707 if (sm_conn->sm_role){ 1708 // responder 1709 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); 1710 } else { 1711 // initiator 1712 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); 1713 } 1714 } 1715 1716 1717 // 1718 // Link Key Conversion Function h6 1719 // 1720 // h6(W, keyID) = AES-CMACW(keyID) 1721 // - W is 128 bits 1722 // - keyID is 32 bits 1723 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1724 const uint16_t message_len = 4; 1725 sm_cmac_connection = sm_conn; 1726 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1727 log_info("h6 key"); 1728 log_info_hexdump(w, 16); 1729 log_info("h6 message"); 1730 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1731 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1732 } 1733 1734 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1735 // Errata Service Release to the Bluetooth Specification: ESR09 1736 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1737 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1738 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1739 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1740 } 1741 1742 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1743 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1744 } 1745 1746 #endif 1747 1748 // key management legacy connections: 1749 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1750 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1751 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1752 // - responder reconnects: responder uses LTK receveived from master 1753 1754 // key management secure connections: 1755 // - both devices store same LTK from ECDH key exchange. 1756 1757 static void sm_load_security_info(sm_connection_t * sm_connection){ 1758 int encryption_key_size; 1759 int authenticated; 1760 int authorized; 1761 1762 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1763 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1764 &encryption_key_size, &authenticated, &authorized); 1765 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1766 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1767 sm_connection->sm_connection_authenticated = authenticated; 1768 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1769 } 1770 1771 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1772 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1773 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1774 // re-establish used key encryption size 1775 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1776 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1777 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1778 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1779 log_info("sm: received ltk request with key size %u, authenticated %u", 1780 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1781 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1782 } 1783 1784 static void sm_run(void){ 1785 1786 btstack_linked_list_iterator_t it; 1787 1788 // assert that we can send at least commands 1789 if (!hci_can_send_command_packet_now()) return; 1790 1791 // 1792 // non-connection related behaviour 1793 // 1794 1795 // distributed key generation 1796 switch (dkg_state){ 1797 case DKG_CALC_IRK: 1798 // already busy? 1799 if (sm_aes128_state == SM_AES128_IDLE) { 1800 // IRK = d1(IR, 1, 0) 1801 sm_key_t d1_prime; 1802 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1803 dkg_next_state(); 1804 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1805 return; 1806 } 1807 break; 1808 case DKG_CALC_DHK: 1809 // already busy? 1810 if (sm_aes128_state == SM_AES128_IDLE) { 1811 // DHK = d1(IR, 3, 0) 1812 sm_key_t d1_prime; 1813 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1814 dkg_next_state(); 1815 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1816 return; 1817 } 1818 break; 1819 default: 1820 break; 1821 } 1822 1823 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1824 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1825 #ifdef USE_MBEDTLS_FOR_ECDH 1826 sm_random_start(NULL); 1827 #else 1828 ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; 1829 hci_send_cmd(&hci_le_read_local_p256_public_key); 1830 #endif 1831 return; 1832 } 1833 #endif 1834 1835 // random address updates 1836 switch (rau_state){ 1837 case RAU_GET_RANDOM: 1838 rau_next_state(); 1839 sm_random_start(NULL); 1840 return; 1841 case RAU_GET_ENC: 1842 // already busy? 1843 if (sm_aes128_state == SM_AES128_IDLE) { 1844 sm_key_t r_prime; 1845 sm_ah_r_prime(sm_random_address, r_prime); 1846 rau_next_state(); 1847 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1848 return; 1849 } 1850 break; 1851 case RAU_SET_ADDRESS: 1852 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1853 rau_state = RAU_IDLE; 1854 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1855 return; 1856 default: 1857 break; 1858 } 1859 1860 // CMAC 1861 switch (sm_cmac_state){ 1862 case CMAC_CALC_SUBKEYS: 1863 case CMAC_CALC_MI: 1864 case CMAC_CALC_MLAST: 1865 // already busy? 1866 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1867 sm_cmac_handle_aes_engine_ready(); 1868 return; 1869 default: 1870 break; 1871 } 1872 1873 // CSRK Lookup 1874 // -- if csrk lookup ready, find connection that require csrk lookup 1875 if (sm_address_resolution_idle()){ 1876 hci_connections_get_iterator(&it); 1877 while(btstack_linked_list_iterator_has_next(&it)){ 1878 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1879 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1880 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1881 // and start lookup 1882 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); 1883 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1884 break; 1885 } 1886 } 1887 } 1888 1889 // -- if csrk lookup ready, resolved addresses for received addresses 1890 if (sm_address_resolution_idle()) { 1891 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1892 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1893 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1894 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1895 btstack_memory_sm_lookup_entry_free(entry); 1896 } 1897 } 1898 1899 // -- Continue with CSRK device lookup by public or resolvable private address 1900 if (!sm_address_resolution_idle()){ 1901 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1902 while (sm_address_resolution_test < le_device_db_count()){ 1903 int addr_type; 1904 bd_addr_t addr; 1905 sm_key_t irk; 1906 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1907 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1908 1909 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1910 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1911 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1912 break; 1913 } 1914 1915 if (sm_address_resolution_addr_type == 0){ 1916 sm_address_resolution_test++; 1917 continue; 1918 } 1919 1920 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1921 1922 log_info("LE Device Lookup: calculate AH"); 1923 log_info_key("IRK", irk); 1924 1925 sm_key_t r_prime; 1926 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1927 sm_address_resolution_ah_calculation_active = 1; 1928 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1929 return; 1930 } 1931 1932 if (sm_address_resolution_test >= le_device_db_count()){ 1933 log_info("LE Device Lookup: not found"); 1934 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1935 } 1936 } 1937 1938 // handle basic actions that don't requires the full context 1939 hci_connections_get_iterator(&it); 1940 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1941 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1942 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1943 switch(sm_connection->sm_engine_state){ 1944 // responder side 1945 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1946 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1947 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1948 return; 1949 1950 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1951 case SM_SC_RECEIVED_LTK_REQUEST: 1952 switch (sm_connection->sm_irk_lookup_state){ 1953 case IRK_LOOKUP_FAILED: 1954 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1955 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1956 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1957 return; 1958 default: 1959 break; 1960 } 1961 break; 1962 #endif 1963 default: 1964 break; 1965 } 1966 } 1967 1968 // 1969 // active connection handling 1970 // -- use loop to handle next connection if lock on setup context is released 1971 1972 while (1) { 1973 1974 // Find connections that requires setup context and make active if no other is locked 1975 hci_connections_get_iterator(&it); 1976 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1977 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1978 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1979 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1980 int done = 1; 1981 int err; 1982 switch (sm_connection->sm_engine_state) { 1983 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1984 // send packet if possible, 1985 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1986 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1987 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1988 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1989 } else { 1990 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1991 } 1992 // don't lock sxetup context yet 1993 done = 0; 1994 break; 1995 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1996 sm_reset_setup(); 1997 sm_init_setup(sm_connection); 1998 // recover pairing request 1999 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2000 err = sm_stk_generation_init(sm_connection); 2001 if (err){ 2002 setup->sm_pairing_failed_reason = err; 2003 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2004 break; 2005 } 2006 sm_timeout_start(sm_connection); 2007 // generate random number first, if we need to show passkey 2008 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2009 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2010 break; 2011 } 2012 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2013 break; 2014 case SM_INITIATOR_PH0_HAS_LTK: 2015 sm_reset_setup(); 2016 sm_load_security_info(sm_connection); 2017 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2018 break; 2019 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2020 sm_reset_setup(); 2021 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2022 break; 2023 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2024 sm_reset_setup(); 2025 sm_init_setup(sm_connection); 2026 sm_timeout_start(sm_connection); 2027 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2028 break; 2029 2030 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2031 case SM_SC_RECEIVED_LTK_REQUEST: 2032 switch (sm_connection->sm_irk_lookup_state){ 2033 case IRK_LOOKUP_SUCCEEDED: 2034 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2035 // start using context by loading security info 2036 sm_reset_setup(); 2037 sm_load_security_info(sm_connection); 2038 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2039 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2040 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2041 break; 2042 } 2043 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2044 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2045 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2046 // don't lock setup context yet 2047 return; 2048 default: 2049 // just wait until IRK lookup is completed 2050 // don't lock setup context yet 2051 done = 0; 2052 break; 2053 } 2054 break; 2055 #endif 2056 default: 2057 done = 0; 2058 break; 2059 } 2060 if (done){ 2061 sm_active_connection = sm_connection->sm_handle; 2062 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2063 } 2064 } 2065 2066 // 2067 // active connection handling 2068 // 2069 2070 if (sm_active_connection == 0) return; 2071 2072 // assert that we could send a SM PDU - not needed for all of the following 2073 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2074 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2075 return; 2076 } 2077 2078 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2079 if (!connection) return; 2080 2081 // send keypress notifications 2082 if (setup->sm_keypress_notification != 0xff){ 2083 uint8_t buffer[2]; 2084 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2085 buffer[1] = setup->sm_keypress_notification; 2086 setup->sm_keypress_notification = 0xff; 2087 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2088 return; 2089 } 2090 2091 sm_key_t plaintext; 2092 int key_distribution_flags; 2093 2094 log_info("sm_run: state %u", connection->sm_engine_state); 2095 2096 switch (connection->sm_engine_state){ 2097 2098 // general 2099 case SM_GENERAL_SEND_PAIRING_FAILED: { 2100 uint8_t buffer[2]; 2101 buffer[0] = SM_CODE_PAIRING_FAILED; 2102 buffer[1] = setup->sm_pairing_failed_reason; 2103 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2104 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2105 sm_done_for_handle(connection->sm_handle); 2106 break; 2107 } 2108 2109 // responding state 2110 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2111 case SM_SC_W2_GET_RANDOM_A: 2112 sm_random_start(connection); 2113 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2114 break; 2115 case SM_SC_W2_GET_RANDOM_B: 2116 sm_random_start(connection); 2117 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2118 break; 2119 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2120 if (!sm_cmac_ready()) break; 2121 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2122 sm_sc_calculate_local_confirm(connection); 2123 break; 2124 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2125 if (!sm_cmac_ready()) break; 2126 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2127 sm_sc_calculate_remote_confirm(connection); 2128 break; 2129 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2130 if (!sm_cmac_ready()) break; 2131 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2132 sm_sc_calculate_f6_for_dhkey_check(connection); 2133 break; 2134 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2135 if (!sm_cmac_ready()) break; 2136 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2137 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2138 break; 2139 case SM_SC_W2_CALCULATE_F5_SALT: 2140 if (!sm_cmac_ready()) break; 2141 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2142 f5_calculate_salt(connection); 2143 break; 2144 case SM_SC_W2_CALCULATE_F5_MACKEY: 2145 if (!sm_cmac_ready()) break; 2146 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2147 f5_calculate_mackey(connection); 2148 break; 2149 case SM_SC_W2_CALCULATE_F5_LTK: 2150 if (!sm_cmac_ready()) break; 2151 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2152 f5_calculate_ltk(connection); 2153 break; 2154 case SM_SC_W2_CALCULATE_G2: 2155 if (!sm_cmac_ready()) break; 2156 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2157 g2_calculate(connection); 2158 break; 2159 case SM_SC_W2_CALCULATE_H6_ILK: 2160 if (!sm_cmac_ready()) break; 2161 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2162 h6_calculate_ilk(connection); 2163 break; 2164 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2165 if (!sm_cmac_ready()) break; 2166 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2167 h6_calculate_br_edr_link_key(connection); 2168 break; 2169 #endif 2170 2171 // initiator side 2172 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2173 sm_key_t peer_ltk_flipped; 2174 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2175 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2176 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2177 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2178 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2179 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2180 return; 2181 } 2182 2183 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2184 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2185 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2186 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2187 sm_timeout_reset(connection); 2188 break; 2189 2190 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2191 2192 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2193 uint8_t buffer[65]; 2194 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2195 // 2196 reverse_256(ec_qx, &buffer[1]); 2197 reverse_256(ec_qy, &buffer[33]); 2198 2199 // stk generation method 2200 // passkey entry: notify app to show passkey or to request passkey 2201 switch (setup->sm_stk_generation_method){ 2202 case JUST_WORKS: 2203 case NK_BOTH_INPUT: 2204 if (connection->sm_role){ 2205 // responder 2206 sm_sc_start_calculating_local_confirm(connection); 2207 } else { 2208 // initiator 2209 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2210 } 2211 break; 2212 case PK_INIT_INPUT: 2213 case PK_RESP_INPUT: 2214 case OK_BOTH_INPUT: 2215 // use random TK for display 2216 memcpy(setup->sm_ra, setup->sm_tk, 16); 2217 memcpy(setup->sm_rb, setup->sm_tk, 16); 2218 setup->sm_passkey_bit = 0; 2219 2220 if (connection->sm_role){ 2221 // responder 2222 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2223 } else { 2224 // initiator 2225 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2226 } 2227 sm_trigger_user_response(connection); 2228 break; 2229 case OOB: 2230 // TODO: implement SC OOB 2231 break; 2232 } 2233 2234 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2235 sm_timeout_reset(connection); 2236 break; 2237 } 2238 case SM_SC_SEND_CONFIRMATION: { 2239 uint8_t buffer[17]; 2240 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2241 reverse_128(setup->sm_local_confirm, &buffer[1]); 2242 if (connection->sm_role){ 2243 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2244 } else { 2245 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2246 } 2247 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2248 sm_timeout_reset(connection); 2249 break; 2250 } 2251 case SM_SC_SEND_PAIRING_RANDOM: { 2252 uint8_t buffer[17]; 2253 buffer[0] = SM_CODE_PAIRING_RANDOM; 2254 reverse_128(setup->sm_local_nonce, &buffer[1]); 2255 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2256 if (connection->sm_role){ 2257 // responder 2258 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2259 } else { 2260 // initiator 2261 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2262 } 2263 } else { 2264 if (connection->sm_role){ 2265 // responder 2266 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2267 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2268 } else { 2269 sm_sc_prepare_dhkey_check(connection); 2270 } 2271 } else { 2272 // initiator 2273 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2274 } 2275 } 2276 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2277 sm_timeout_reset(connection); 2278 break; 2279 } 2280 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2281 uint8_t buffer[17]; 2282 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2283 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2284 2285 if (connection->sm_role){ 2286 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2287 } else { 2288 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2289 } 2290 2291 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2292 sm_timeout_reset(connection); 2293 break; 2294 } 2295 2296 #endif 2297 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2298 // echo initiator for now 2299 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2300 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2301 2302 if (setup->sm_use_secure_connections){ 2303 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2304 // skip LTK/EDIV for SC 2305 log_info("sm: dropping encryption information flag"); 2306 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2307 } else { 2308 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2309 } 2310 2311 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); 2312 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); 2313 // update key distribution after ENC was dropped 2314 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2315 2316 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2317 sm_timeout_reset(connection); 2318 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2319 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2320 sm_trigger_user_response(connection); 2321 } 2322 return; 2323 2324 case SM_PH2_SEND_PAIRING_RANDOM: { 2325 uint8_t buffer[17]; 2326 buffer[0] = SM_CODE_PAIRING_RANDOM; 2327 reverse_128(setup->sm_local_random, &buffer[1]); 2328 if (connection->sm_role){ 2329 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2330 } else { 2331 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2332 } 2333 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2334 sm_timeout_reset(connection); 2335 break; 2336 } 2337 2338 case SM_PH2_GET_RANDOM_TK: 2339 case SM_PH2_C1_GET_RANDOM_A: 2340 case SM_PH2_C1_GET_RANDOM_B: 2341 case SM_PH3_GET_RANDOM: 2342 case SM_PH3_GET_DIV: 2343 sm_next_responding_state(connection); 2344 sm_random_start(connection); 2345 return; 2346 2347 case SM_PH2_C1_GET_ENC_B: 2348 case SM_PH2_C1_GET_ENC_D: 2349 // already busy? 2350 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2351 sm_next_responding_state(connection); 2352 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2353 return; 2354 2355 case SM_PH3_LTK_GET_ENC: 2356 case SM_RESPONDER_PH4_LTK_GET_ENC: 2357 // already busy? 2358 if (sm_aes128_state == SM_AES128_IDLE) { 2359 sm_key_t d_prime; 2360 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2361 sm_next_responding_state(connection); 2362 sm_aes128_start(sm_persistent_er, d_prime, connection); 2363 return; 2364 } 2365 break; 2366 2367 case SM_PH3_CSRK_GET_ENC: 2368 // already busy? 2369 if (sm_aes128_state == SM_AES128_IDLE) { 2370 sm_key_t d_prime; 2371 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2372 sm_next_responding_state(connection); 2373 sm_aes128_start(sm_persistent_er, d_prime, connection); 2374 return; 2375 } 2376 break; 2377 2378 case SM_PH2_C1_GET_ENC_C: 2379 // already busy? 2380 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2381 // calculate m_confirm using aes128 engine - step 1 2382 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); 2383 sm_next_responding_state(connection); 2384 sm_aes128_start(setup->sm_tk, plaintext, connection); 2385 break; 2386 case SM_PH2_C1_GET_ENC_A: 2387 // already busy? 2388 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2389 // calculate confirm using aes128 engine - step 1 2390 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); 2391 sm_next_responding_state(connection); 2392 sm_aes128_start(setup->sm_tk, plaintext, connection); 2393 break; 2394 case SM_PH2_CALC_STK: 2395 // already busy? 2396 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2397 // calculate STK 2398 if (connection->sm_role){ 2399 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2400 } else { 2401 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2402 } 2403 sm_next_responding_state(connection); 2404 sm_aes128_start(setup->sm_tk, plaintext, connection); 2405 break; 2406 case SM_PH3_Y_GET_ENC: 2407 // already busy? 2408 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2409 // PH3B2 - calculate Y from - enc 2410 // Y = dm(DHK, Rand) 2411 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2412 sm_next_responding_state(connection); 2413 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2414 return; 2415 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2416 uint8_t buffer[17]; 2417 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2418 reverse_128(setup->sm_local_confirm, &buffer[1]); 2419 if (connection->sm_role){ 2420 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2421 } else { 2422 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2423 } 2424 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2425 sm_timeout_reset(connection); 2426 return; 2427 } 2428 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2429 sm_key_t stk_flipped; 2430 reverse_128(setup->sm_ltk, stk_flipped); 2431 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2432 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2433 return; 2434 } 2435 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2436 sm_key_t stk_flipped; 2437 reverse_128(setup->sm_ltk, stk_flipped); 2438 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2439 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2440 return; 2441 } 2442 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2443 sm_key_t ltk_flipped; 2444 reverse_128(setup->sm_ltk, ltk_flipped); 2445 connection->sm_engine_state = SM_RESPONDER_IDLE; 2446 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2447 return; 2448 } 2449 case SM_RESPONDER_PH4_Y_GET_ENC: 2450 // already busy? 2451 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2452 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2453 // Y = dm(DHK, Rand) 2454 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2455 sm_next_responding_state(connection); 2456 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2457 return; 2458 2459 case SM_PH3_DISTRIBUTE_KEYS: 2460 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2461 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2462 uint8_t buffer[17]; 2463 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2464 reverse_128(setup->sm_ltk, &buffer[1]); 2465 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2466 sm_timeout_reset(connection); 2467 return; 2468 } 2469 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2470 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2471 uint8_t buffer[11]; 2472 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2473 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2474 reverse_64(setup->sm_local_rand, &buffer[3]); 2475 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2476 sm_timeout_reset(connection); 2477 return; 2478 } 2479 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2480 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2481 uint8_t buffer[17]; 2482 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2483 reverse_128(sm_persistent_irk, &buffer[1]); 2484 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2485 sm_timeout_reset(connection); 2486 return; 2487 } 2488 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2489 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2490 bd_addr_t local_address; 2491 uint8_t buffer[8]; 2492 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2493 gap_advertisements_get_address(&buffer[1], local_address); 2494 reverse_bd_addr(local_address, &buffer[2]); 2495 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2496 sm_timeout_reset(connection); 2497 return; 2498 } 2499 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2500 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2501 2502 // hack to reproduce test runs 2503 if (test_use_fixed_local_csrk){ 2504 memset(setup->sm_local_csrk, 0xcc, 16); 2505 } 2506 2507 uint8_t buffer[17]; 2508 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2509 reverse_128(setup->sm_local_csrk, &buffer[1]); 2510 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2511 sm_timeout_reset(connection); 2512 return; 2513 } 2514 2515 // keys are sent 2516 if (connection->sm_role){ 2517 // slave -> receive master keys if any 2518 if (sm_key_distribution_all_received(connection)){ 2519 sm_key_distribution_handle_all_received(connection); 2520 connection->sm_engine_state = SM_RESPONDER_IDLE; 2521 sm_done_for_handle(connection->sm_handle); 2522 } else { 2523 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2524 } 2525 } else { 2526 // master -> all done 2527 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2528 sm_done_for_handle(connection->sm_handle); 2529 } 2530 break; 2531 2532 default: 2533 break; 2534 } 2535 2536 // check again if active connection was released 2537 if (sm_active_connection) break; 2538 } 2539 } 2540 2541 // note: aes engine is ready as we just got the aes result 2542 static void sm_handle_encryption_result(uint8_t * data){ 2543 2544 sm_aes128_state = SM_AES128_IDLE; 2545 2546 if (sm_address_resolution_ah_calculation_active){ 2547 sm_address_resolution_ah_calculation_active = 0; 2548 // compare calulated address against connecting device 2549 uint8_t hash[3]; 2550 reverse_24(data, hash); 2551 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2552 log_info("LE Device Lookup: matched resolvable private address"); 2553 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2554 return; 2555 } 2556 // no match, try next 2557 sm_address_resolution_test++; 2558 return; 2559 } 2560 2561 switch (dkg_state){ 2562 case DKG_W4_IRK: 2563 reverse_128(data, sm_persistent_irk); 2564 log_info_key("irk", sm_persistent_irk); 2565 dkg_next_state(); 2566 return; 2567 case DKG_W4_DHK: 2568 reverse_128(data, sm_persistent_dhk); 2569 log_info_key("dhk", sm_persistent_dhk); 2570 dkg_next_state(); 2571 // SM Init Finished 2572 return; 2573 default: 2574 break; 2575 } 2576 2577 switch (rau_state){ 2578 case RAU_W4_ENC: 2579 reverse_24(data, &sm_random_address[3]); 2580 rau_next_state(); 2581 return; 2582 default: 2583 break; 2584 } 2585 2586 switch (sm_cmac_state){ 2587 case CMAC_W4_SUBKEYS: 2588 case CMAC_W4_MI: 2589 case CMAC_W4_MLAST: 2590 { 2591 sm_key_t t; 2592 reverse_128(data, t); 2593 sm_cmac_handle_encryption_result(t); 2594 } 2595 return; 2596 default: 2597 break; 2598 } 2599 2600 // retrieve sm_connection provided to sm_aes128_start_encryption 2601 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2602 if (!connection) return; 2603 switch (connection->sm_engine_state){ 2604 case SM_PH2_C1_W4_ENC_A: 2605 case SM_PH2_C1_W4_ENC_C: 2606 { 2607 sm_key_t t2; 2608 reverse_128(data, t2); 2609 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2610 } 2611 sm_next_responding_state(connection); 2612 return; 2613 case SM_PH2_C1_W4_ENC_B: 2614 reverse_128(data, setup->sm_local_confirm); 2615 log_info_key("c1!", setup->sm_local_confirm); 2616 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2617 return; 2618 case SM_PH2_C1_W4_ENC_D: 2619 { 2620 sm_key_t peer_confirm_test; 2621 reverse_128(data, peer_confirm_test); 2622 log_info_key("c1!", peer_confirm_test); 2623 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2624 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2625 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2626 return; 2627 } 2628 if (connection->sm_role){ 2629 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2630 } else { 2631 connection->sm_engine_state = SM_PH2_CALC_STK; 2632 } 2633 } 2634 return; 2635 case SM_PH2_W4_STK: 2636 reverse_128(data, setup->sm_ltk); 2637 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2638 log_info_key("stk", setup->sm_ltk); 2639 if (connection->sm_role){ 2640 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2641 } else { 2642 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2643 } 2644 return; 2645 case SM_PH3_Y_W4_ENC:{ 2646 sm_key_t y128; 2647 reverse_128(data, y128); 2648 setup->sm_local_y = big_endian_read_16(y128, 14); 2649 log_info_hex16("y", setup->sm_local_y); 2650 // PH3B3 - calculate EDIV 2651 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2652 log_info_hex16("ediv", setup->sm_local_ediv); 2653 // PH3B4 - calculate LTK - enc 2654 // LTK = d1(ER, DIV, 0)) 2655 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2656 return; 2657 } 2658 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2659 sm_key_t y128; 2660 reverse_128(data, y128); 2661 setup->sm_local_y = big_endian_read_16(y128, 14); 2662 log_info_hex16("y", setup->sm_local_y); 2663 2664 // PH3B3 - calculate DIV 2665 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2666 log_info_hex16("ediv", setup->sm_local_ediv); 2667 // PH3B4 - calculate LTK - enc 2668 // LTK = d1(ER, DIV, 0)) 2669 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2670 return; 2671 } 2672 case SM_PH3_LTK_W4_ENC: 2673 reverse_128(data, setup->sm_ltk); 2674 log_info_key("ltk", setup->sm_ltk); 2675 // calc CSRK next 2676 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2677 return; 2678 case SM_PH3_CSRK_W4_ENC: 2679 reverse_128(data, setup->sm_local_csrk); 2680 log_info_key("csrk", setup->sm_local_csrk); 2681 if (setup->sm_key_distribution_send_set){ 2682 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2683 } else { 2684 // no keys to send, just continue 2685 if (connection->sm_role){ 2686 // slave -> receive master keys 2687 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2688 } else { 2689 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2690 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2691 } else { 2692 // master -> all done 2693 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2694 sm_done_for_handle(connection->sm_handle); 2695 } 2696 } 2697 } 2698 return; 2699 case SM_RESPONDER_PH4_LTK_W4_ENC: 2700 reverse_128(data, setup->sm_ltk); 2701 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2702 log_info_key("ltk", setup->sm_ltk); 2703 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2704 return; 2705 default: 2706 break; 2707 } 2708 } 2709 2710 #ifdef USE_MBEDTLS_FOR_ECDH 2711 2712 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2713 UNUSED(context); 2714 2715 int offset = setup->sm_passkey_bit; 2716 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2717 while (size) { 2718 if (offset < 32){ 2719 *buffer++ = setup->sm_peer_qx[offset++]; 2720 } else { 2721 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2722 } 2723 size--; 2724 } 2725 setup->sm_passkey_bit = offset; 2726 return 0; 2727 } 2728 #endif 2729 2730 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2731 static void sm_handle_random_result(uint8_t * data){ 2732 2733 #ifdef USE_MBEDTLS_FOR_ECDH 2734 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2735 int num_bytes = setup->sm_passkey_bit; 2736 if (num_bytes < 32){ 2737 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2738 } else { 2739 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2740 } 2741 num_bytes += 8; 2742 setup->sm_passkey_bit = num_bytes; 2743 2744 if (num_bytes >= 64){ 2745 2746 // generate EC key 2747 setup->sm_passkey_bit = 0; 2748 mbedtls_mpi d; 2749 mbedtls_ecp_point P; 2750 mbedtls_mpi_init(&d); 2751 mbedtls_ecp_point_init(&P); 2752 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2753 log_info("gen keypair %x", res); 2754 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2755 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2756 mbedtls_mpi_write_binary(&d, ec_d, 32); 2757 mbedtls_ecp_point_free(&P); 2758 mbedtls_mpi_free(&d); 2759 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2760 log_info("Elliptic curve: d"); 2761 log_info_hexdump(ec_d,32); 2762 sm_log_ec_keypair(); 2763 2764 #if 0 2765 int i; 2766 sm_key256_t dhkey; 2767 for (i=0;i<10;i++){ 2768 // printf("test dhkey check\n"); 2769 memcpy(setup->sm_peer_qx, ec_qx, 32); 2770 memcpy(setup->sm_peer_qy, ec_qy, 32); 2771 sm_sc_calculate_dhkey(dhkey); 2772 // printf("test dhkey check end\n"); 2773 } 2774 #endif 2775 2776 } 2777 } 2778 #endif 2779 2780 switch (rau_state){ 2781 case RAU_W4_RANDOM: 2782 // non-resolvable vs. resolvable 2783 switch (gap_random_adress_type){ 2784 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2785 // resolvable: use random as prand and calc address hash 2786 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2787 memcpy(sm_random_address, data, 3); 2788 sm_random_address[0] &= 0x3f; 2789 sm_random_address[0] |= 0x40; 2790 rau_state = RAU_GET_ENC; 2791 break; 2792 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2793 default: 2794 // "The two most significant bits of the address shall be equal to ‘0’"" 2795 memcpy(sm_random_address, data, 6); 2796 sm_random_address[0] &= 0x3f; 2797 rau_state = RAU_SET_ADDRESS; 2798 break; 2799 } 2800 return; 2801 default: 2802 break; 2803 } 2804 2805 // retrieve sm_connection provided to sm_random_start 2806 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2807 if (!connection) return; 2808 switch (connection->sm_engine_state){ 2809 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2810 case SM_SC_W4_GET_RANDOM_A: 2811 memcpy(&setup->sm_local_nonce[0], data, 8); 2812 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2813 break; 2814 case SM_SC_W4_GET_RANDOM_B: 2815 memcpy(&setup->sm_local_nonce[8], data, 8); 2816 // initiator & jw/nc -> send pairing random 2817 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2818 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2819 break; 2820 } else { 2821 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2822 } 2823 break; 2824 #endif 2825 2826 case SM_PH2_W4_RANDOM_TK: 2827 { 2828 // map random to 0-999999 without speding much cycles on a modulus operation 2829 uint32_t tk = little_endian_read_32(data,0); 2830 tk = tk & 0xfffff; // 1048575 2831 if (tk >= 999999){ 2832 tk = tk - 999999; 2833 } 2834 sm_reset_tk(); 2835 big_endian_store_32(setup->sm_tk, 12, tk); 2836 if (connection->sm_role){ 2837 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2838 } else { 2839 if (setup->sm_use_secure_connections){ 2840 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2841 } else { 2842 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2843 sm_trigger_user_response(connection); 2844 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2845 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2846 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2847 } 2848 } 2849 } 2850 return; 2851 } 2852 case SM_PH2_C1_W4_RANDOM_A: 2853 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2854 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2855 return; 2856 case SM_PH2_C1_W4_RANDOM_B: 2857 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2858 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2859 return; 2860 case SM_PH3_W4_RANDOM: 2861 reverse_64(data, setup->sm_local_rand); 2862 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2863 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2864 // no db for authenticated flag hack: store flag in bit 4 of LSB 2865 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2866 connection->sm_engine_state = SM_PH3_GET_DIV; 2867 return; 2868 case SM_PH3_W4_DIV: 2869 // use 16 bit from random value as div 2870 setup->sm_local_div = big_endian_read_16(data, 0); 2871 log_info_hex16("div", setup->sm_local_div); 2872 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2873 return; 2874 default: 2875 break; 2876 } 2877 } 2878 2879 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2880 2881 UNUSED(channel); 2882 UNUSED(size); 2883 2884 sm_connection_t * sm_conn; 2885 hci_con_handle_t con_handle; 2886 2887 switch (packet_type) { 2888 2889 case HCI_EVENT_PACKET: 2890 switch (hci_event_packet_get_type(packet)) { 2891 2892 case BTSTACK_EVENT_STATE: 2893 // bt stack activated, get started 2894 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2895 log_info("HCI Working!"); 2896 2897 // set local addr for le device db 2898 bd_addr_t local_bd_addr; 2899 gap_local_bd_addr(local_bd_addr); 2900 le_device_db_set_local_bd_addr(local_bd_addr); 2901 2902 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2903 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2904 if (!sm_have_ec_keypair){ 2905 setup->sm_passkey_bit = 0; 2906 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2907 } 2908 #endif 2909 // trigger Random Address generation if requested before 2910 switch (gap_random_adress_type){ 2911 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2912 rau_state = RAU_IDLE; 2913 break; 2914 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2915 rau_state = RAU_SET_ADDRESS; 2916 break; 2917 default: 2918 rau_state = RAU_GET_RANDOM; 2919 break; 2920 } 2921 sm_run(); 2922 } 2923 break; 2924 2925 case HCI_EVENT_LE_META: 2926 switch (packet[2]) { 2927 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2928 2929 log_info("sm: connected"); 2930 2931 if (packet[3]) return; // connection failed 2932 2933 con_handle = little_endian_read_16(packet, 4); 2934 sm_conn = sm_get_connection_for_handle(con_handle); 2935 if (!sm_conn) break; 2936 2937 sm_conn->sm_handle = con_handle; 2938 sm_conn->sm_role = packet[6]; 2939 sm_conn->sm_peer_addr_type = packet[7]; 2940 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 2941 2942 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2943 2944 // reset security properties 2945 sm_conn->sm_connection_encrypted = 0; 2946 sm_conn->sm_connection_authenticated = 0; 2947 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2948 sm_conn->sm_le_db_index = -1; 2949 2950 // prepare CSRK lookup (does not involve setup) 2951 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2952 2953 // just connected -> everything else happens in sm_run() 2954 if (sm_conn->sm_role){ 2955 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2956 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2957 if (sm_slave_request_security) { 2958 // request security if requested by app 2959 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2960 } else { 2961 // otherwise, wait for pairing request 2962 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2963 } 2964 } 2965 break; 2966 } else { 2967 // master 2968 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2969 } 2970 break; 2971 2972 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2973 con_handle = little_endian_read_16(packet, 3); 2974 sm_conn = sm_get_connection_for_handle(con_handle); 2975 if (!sm_conn) break; 2976 2977 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2978 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2979 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2980 break; 2981 } 2982 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2983 // PH2 SEND LTK as we need to exchange keys in PH3 2984 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2985 break; 2986 } 2987 2988 // store rand and ediv 2989 reverse_64(&packet[5], sm_conn->sm_local_rand); 2990 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2991 2992 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2993 // potentially stored LTK is from the master 2994 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2995 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2996 break; 2997 } 2998 2999 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3000 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3001 #else 3002 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3003 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3004 #endif 3005 break; 3006 3007 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3008 case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: 3009 if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ 3010 log_error("Read Local P256 Public Key failed"); 3011 break; 3012 } 3013 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, ec_qx); 3014 hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, ec_qy); 3015 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3016 sm_log_ec_keypair(); 3017 break; 3018 #endif 3019 default: 3020 break; 3021 } 3022 break; 3023 3024 case HCI_EVENT_ENCRYPTION_CHANGE: 3025 con_handle = little_endian_read_16(packet, 3); 3026 sm_conn = sm_get_connection_for_handle(con_handle); 3027 if (!sm_conn) break; 3028 3029 sm_conn->sm_connection_encrypted = packet[5]; 3030 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3031 sm_conn->sm_actual_encryption_key_size); 3032 log_info("event handler, state %u", sm_conn->sm_engine_state); 3033 if (!sm_conn->sm_connection_encrypted) break; 3034 // continue if part of initial pairing 3035 switch (sm_conn->sm_engine_state){ 3036 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3037 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3038 sm_done_for_handle(sm_conn->sm_handle); 3039 break; 3040 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3041 if (sm_conn->sm_role){ 3042 // slave 3043 if (setup->sm_use_secure_connections){ 3044 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3045 } else { 3046 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3047 } 3048 } else { 3049 // master 3050 if (sm_key_distribution_all_received(sm_conn)){ 3051 // skip receiving keys as there are none 3052 sm_key_distribution_handle_all_received(sm_conn); 3053 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3054 } else { 3055 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3056 } 3057 } 3058 break; 3059 default: 3060 break; 3061 } 3062 break; 3063 3064 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3065 con_handle = little_endian_read_16(packet, 3); 3066 sm_conn = sm_get_connection_for_handle(con_handle); 3067 if (!sm_conn) break; 3068 3069 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3070 log_info("event handler, state %u", sm_conn->sm_engine_state); 3071 // continue if part of initial pairing 3072 switch (sm_conn->sm_engine_state){ 3073 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3074 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3075 sm_done_for_handle(sm_conn->sm_handle); 3076 break; 3077 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3078 if (sm_conn->sm_role){ 3079 // slave 3080 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3081 } else { 3082 // master 3083 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3084 } 3085 break; 3086 default: 3087 break; 3088 } 3089 break; 3090 3091 3092 case HCI_EVENT_DISCONNECTION_COMPLETE: 3093 con_handle = little_endian_read_16(packet, 3); 3094 sm_done_for_handle(con_handle); 3095 sm_conn = sm_get_connection_for_handle(con_handle); 3096 if (!sm_conn) break; 3097 3098 // delete stored bonding on disconnect with authentication failure in ph0 3099 if (sm_conn->sm_role == 0 3100 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3101 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3102 le_device_db_remove(sm_conn->sm_le_db_index); 3103 } 3104 3105 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3106 sm_conn->sm_handle = 0; 3107 break; 3108 3109 case HCI_EVENT_COMMAND_COMPLETE: 3110 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3111 sm_handle_encryption_result(&packet[6]); 3112 break; 3113 } 3114 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3115 sm_handle_random_result(&packet[6]); 3116 break; 3117 } 3118 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3119 // Hack for Nordic nRF5 series that doesn't have public address: 3120 // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address 3121 // - we use this as default for advertisements/connections 3122 if (hci_get_manufacturer() == COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ 3123 log_info("nRF5: using (fake) public address as random static address"); 3124 bd_addr_t addr; 3125 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3126 gap_random_address_set(addr); 3127 } 3128 } 3129 break; 3130 default: 3131 break; 3132 } 3133 break; 3134 default: 3135 break; 3136 } 3137 3138 sm_run(); 3139 } 3140 3141 static inline int sm_calc_actual_encryption_key_size(int other){ 3142 if (other < sm_min_encryption_key_size) return 0; 3143 if (other < sm_max_encryption_key_size) return other; 3144 return sm_max_encryption_key_size; 3145 } 3146 3147 3148 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3149 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3150 switch (method){ 3151 case JUST_WORKS: 3152 case NK_BOTH_INPUT: 3153 return 1; 3154 default: 3155 return 0; 3156 } 3157 } 3158 // responder 3159 3160 static int sm_passkey_used(stk_generation_method_t method){ 3161 switch (method){ 3162 case PK_RESP_INPUT: 3163 return 1; 3164 default: 3165 return 0; 3166 } 3167 } 3168 #endif 3169 3170 /** 3171 * @return ok 3172 */ 3173 static int sm_validate_stk_generation_method(void){ 3174 // check if STK generation method is acceptable by client 3175 switch (setup->sm_stk_generation_method){ 3176 case JUST_WORKS: 3177 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3178 case PK_RESP_INPUT: 3179 case PK_INIT_INPUT: 3180 case OK_BOTH_INPUT: 3181 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3182 case OOB: 3183 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3184 case NK_BOTH_INPUT: 3185 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3186 return 1; 3187 default: 3188 return 0; 3189 } 3190 } 3191 3192 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3193 3194 UNUSED(size); 3195 3196 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3197 sm_run(); 3198 } 3199 3200 if (packet_type != SM_DATA_PACKET) return; 3201 3202 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3203 if (!sm_conn) return; 3204 3205 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3206 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3207 return; 3208 } 3209 3210 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3211 3212 int err; 3213 3214 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3215 uint8_t buffer[5]; 3216 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3217 buffer[1] = 3; 3218 little_endian_store_16(buffer, 2, con_handle); 3219 buffer[4] = packet[1]; 3220 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3221 return; 3222 } 3223 3224 switch (sm_conn->sm_engine_state){ 3225 3226 // a sm timeout requries a new physical connection 3227 case SM_GENERAL_TIMEOUT: 3228 return; 3229 3230 // Initiator 3231 case SM_INITIATOR_CONNECTED: 3232 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3233 sm_pdu_received_in_wrong_state(sm_conn); 3234 break; 3235 } 3236 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3237 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3238 break; 3239 } 3240 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3241 sm_key_t ltk; 3242 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3243 if (!sm_is_null_key(ltk)){ 3244 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3245 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3246 } else { 3247 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3248 } 3249 break; 3250 } 3251 // otherwise, store security request 3252 sm_conn->sm_security_request_received = 1; 3253 break; 3254 3255 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3256 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3257 sm_pdu_received_in_wrong_state(sm_conn); 3258 break; 3259 } 3260 // store pairing request 3261 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3262 err = sm_stk_generation_init(sm_conn); 3263 if (err){ 3264 setup->sm_pairing_failed_reason = err; 3265 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3266 break; 3267 } 3268 3269 // generate random number first, if we need to show passkey 3270 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3271 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3272 break; 3273 } 3274 3275 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3276 if (setup->sm_use_secure_connections){ 3277 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3278 if (setup->sm_stk_generation_method == JUST_WORKS){ 3279 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3280 sm_trigger_user_response(sm_conn); 3281 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3282 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3283 } 3284 } else { 3285 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3286 } 3287 break; 3288 } 3289 #endif 3290 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3291 sm_trigger_user_response(sm_conn); 3292 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3293 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3294 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3295 } 3296 break; 3297 3298 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3299 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3300 sm_pdu_received_in_wrong_state(sm_conn); 3301 break; 3302 } 3303 3304 // store s_confirm 3305 reverse_128(&packet[1], setup->sm_peer_confirm); 3306 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3307 break; 3308 3309 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3310 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3311 sm_pdu_received_in_wrong_state(sm_conn); 3312 break;; 3313 } 3314 3315 // received random value 3316 reverse_128(&packet[1], setup->sm_peer_random); 3317 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3318 break; 3319 3320 // Responder 3321 case SM_RESPONDER_IDLE: 3322 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3323 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3324 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3325 sm_pdu_received_in_wrong_state(sm_conn); 3326 break;; 3327 } 3328 3329 // store pairing request 3330 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3331 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3332 break; 3333 3334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3335 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3336 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3337 sm_pdu_received_in_wrong_state(sm_conn); 3338 break; 3339 } 3340 3341 // store public key for DH Key calculation 3342 reverse_256(&packet[01], setup->sm_peer_qx); 3343 reverse_256(&packet[33], setup->sm_peer_qy); 3344 3345 #ifdef USE_MBEDTLS_FOR_ECDH 3346 // validate public key 3347 mbedtls_ecp_point Q; 3348 mbedtls_ecp_point_init( &Q ); 3349 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3350 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3351 mbedtls_mpi_lset(&Q.Z, 1); 3352 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3353 mbedtls_ecp_point_free( & Q); 3354 if (err){ 3355 log_error("sm: peer public key invalid %x", err); 3356 // uses "unspecified reason", there is no "public key invalid" error code 3357 sm_pdu_received_in_wrong_state(sm_conn); 3358 break; 3359 } 3360 3361 #endif 3362 if (sm_conn->sm_role){ 3363 // responder 3364 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3365 } else { 3366 // initiator 3367 // stk generation method 3368 // passkey entry: notify app to show passkey or to request passkey 3369 switch (setup->sm_stk_generation_method){ 3370 case JUST_WORKS: 3371 case NK_BOTH_INPUT: 3372 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3373 break; 3374 case PK_RESP_INPUT: 3375 sm_sc_start_calculating_local_confirm(sm_conn); 3376 break; 3377 case PK_INIT_INPUT: 3378 case OK_BOTH_INPUT: 3379 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3380 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3381 break; 3382 } 3383 sm_sc_start_calculating_local_confirm(sm_conn); 3384 break; 3385 case OOB: 3386 // TODO: implement SC OOB 3387 break; 3388 } 3389 } 3390 break; 3391 3392 case SM_SC_W4_CONFIRMATION: 3393 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3394 sm_pdu_received_in_wrong_state(sm_conn); 3395 break; 3396 } 3397 // received confirm value 3398 reverse_128(&packet[1], setup->sm_peer_confirm); 3399 3400 if (sm_conn->sm_role){ 3401 // responder 3402 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3403 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3404 // still waiting for passkey 3405 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3406 break; 3407 } 3408 } 3409 sm_sc_start_calculating_local_confirm(sm_conn); 3410 } else { 3411 // initiator 3412 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3413 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3414 } else { 3415 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3416 } 3417 } 3418 break; 3419 3420 case SM_SC_W4_PAIRING_RANDOM: 3421 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3422 sm_pdu_received_in_wrong_state(sm_conn); 3423 break; 3424 } 3425 3426 // received random value 3427 reverse_128(&packet[1], setup->sm_peer_nonce); 3428 3429 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3430 // only check for JUST WORK/NC in initiator role AND passkey entry 3431 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3432 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3433 } 3434 3435 sm_sc_state_after_receiving_random(sm_conn); 3436 break; 3437 3438 case SM_SC_W2_CALCULATE_G2: 3439 case SM_SC_W4_CALCULATE_G2: 3440 case SM_SC_W2_CALCULATE_F5_SALT: 3441 case SM_SC_W4_CALCULATE_F5_SALT: 3442 case SM_SC_W2_CALCULATE_F5_MACKEY: 3443 case SM_SC_W4_CALCULATE_F5_MACKEY: 3444 case SM_SC_W2_CALCULATE_F5_LTK: 3445 case SM_SC_W4_CALCULATE_F5_LTK: 3446 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3447 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3448 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3449 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3450 sm_pdu_received_in_wrong_state(sm_conn); 3451 break; 3452 } 3453 // store DHKey Check 3454 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3455 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3456 3457 // have we been only waiting for dhkey check command? 3458 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3459 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3460 } 3461 break; 3462 #endif 3463 3464 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3465 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3466 sm_pdu_received_in_wrong_state(sm_conn); 3467 break; 3468 } 3469 3470 // received confirm value 3471 reverse_128(&packet[1], setup->sm_peer_confirm); 3472 3473 // notify client to hide shown passkey 3474 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3475 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3476 } 3477 3478 // handle user cancel pairing? 3479 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3480 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3481 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3482 break; 3483 } 3484 3485 // wait for user action? 3486 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3487 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3488 break; 3489 } 3490 3491 // calculate and send local_confirm 3492 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3493 break; 3494 3495 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3496 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3497 sm_pdu_received_in_wrong_state(sm_conn); 3498 break;; 3499 } 3500 3501 // received random value 3502 reverse_128(&packet[1], setup->sm_peer_random); 3503 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3504 break; 3505 3506 case SM_PH3_RECEIVE_KEYS: 3507 switch(packet[0]){ 3508 case SM_CODE_ENCRYPTION_INFORMATION: 3509 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3510 reverse_128(&packet[1], setup->sm_peer_ltk); 3511 break; 3512 3513 case SM_CODE_MASTER_IDENTIFICATION: 3514 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3515 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3516 reverse_64(&packet[3], setup->sm_peer_rand); 3517 break; 3518 3519 case SM_CODE_IDENTITY_INFORMATION: 3520 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3521 reverse_128(&packet[1], setup->sm_peer_irk); 3522 break; 3523 3524 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3525 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3526 setup->sm_peer_addr_type = packet[1]; 3527 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3528 break; 3529 3530 case SM_CODE_SIGNING_INFORMATION: 3531 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3532 reverse_128(&packet[1], setup->sm_peer_csrk); 3533 break; 3534 default: 3535 // Unexpected PDU 3536 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3537 break; 3538 } 3539 // done with key distribution? 3540 if (sm_key_distribution_all_received(sm_conn)){ 3541 3542 sm_key_distribution_handle_all_received(sm_conn); 3543 3544 if (sm_conn->sm_role){ 3545 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3546 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3547 } else { 3548 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3549 sm_done_for_handle(sm_conn->sm_handle); 3550 } 3551 } else { 3552 if (setup->sm_use_secure_connections){ 3553 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3554 } else { 3555 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3556 } 3557 } 3558 } 3559 break; 3560 default: 3561 // Unexpected PDU 3562 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3563 break; 3564 } 3565 3566 // try to send preparared packet 3567 sm_run(); 3568 } 3569 3570 // Security Manager Client API 3571 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3572 sm_get_oob_data = get_oob_data_callback; 3573 } 3574 3575 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3576 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3577 } 3578 3579 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3580 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3581 } 3582 3583 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3584 sm_min_encryption_key_size = min_size; 3585 sm_max_encryption_key_size = max_size; 3586 } 3587 3588 void sm_set_authentication_requirements(uint8_t auth_req){ 3589 sm_auth_req = auth_req; 3590 } 3591 3592 void sm_set_io_capabilities(io_capability_t io_capability){ 3593 sm_io_capabilities = io_capability; 3594 } 3595 3596 void sm_set_request_security(int enable){ 3597 sm_slave_request_security = enable; 3598 } 3599 3600 void sm_set_er(sm_key_t er){ 3601 memcpy(sm_persistent_er, er, 16); 3602 } 3603 3604 void sm_set_ir(sm_key_t ir){ 3605 memcpy(sm_persistent_ir, ir, 16); 3606 } 3607 3608 // Testing support only 3609 void sm_test_set_irk(sm_key_t irk){ 3610 memcpy(sm_persistent_irk, irk, 16); 3611 sm_persistent_irk_ready = 1; 3612 } 3613 3614 void sm_test_use_fixed_local_csrk(void){ 3615 test_use_fixed_local_csrk = 1; 3616 } 3617 3618 void sm_init(void){ 3619 // set some (BTstack default) ER and IR 3620 int i; 3621 sm_key_t er; 3622 sm_key_t ir; 3623 for (i=0;i<16;i++){ 3624 er[i] = 0x30 + i; 3625 ir[i] = 0x90 + i; 3626 } 3627 sm_set_er(er); 3628 sm_set_ir(ir); 3629 // defaults 3630 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3631 | SM_STK_GENERATION_METHOD_OOB 3632 | SM_STK_GENERATION_METHOD_PASSKEY 3633 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3634 3635 sm_max_encryption_key_size = 16; 3636 sm_min_encryption_key_size = 7; 3637 3638 sm_cmac_state = CMAC_IDLE; 3639 dkg_state = DKG_W4_WORKING; 3640 rau_state = RAU_W4_WORKING; 3641 sm_aes128_state = SM_AES128_IDLE; 3642 sm_address_resolution_test = -1; // no private address to resolve yet 3643 sm_address_resolution_ah_calculation_active = 0; 3644 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3645 sm_address_resolution_general_queue = NULL; 3646 3647 gap_random_adress_update_period = 15 * 60 * 1000L; 3648 sm_active_connection = 0; 3649 3650 test_use_fixed_local_csrk = 0; 3651 3652 // register for HCI Events from HCI 3653 hci_event_callback_registration.callback = &sm_event_packet_handler; 3654 hci_add_event_handler(&hci_event_callback_registration); 3655 3656 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3657 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3658 3659 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3660 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3661 #endif 3662 3663 #ifdef USE_MBEDTLS_FOR_ECDH 3664 3665 #ifndef HAVE_MALLOC 3666 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3667 #endif 3668 mbedtls_ecp_group_init(&mbedtls_ec_group); 3669 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3670 #if 0 3671 // test 3672 sm_test_use_fixed_ec_keypair(); 3673 if (sm_have_ec_keypair){ 3674 printf("test dhkey check\n"); 3675 sm_key256_t dhkey; 3676 memcpy(setup->sm_peer_qx, ec_qx, 32); 3677 memcpy(setup->sm_peer_qy, ec_qy, 32); 3678 sm_sc_calculate_dhkey(dhkey); 3679 } 3680 #endif 3681 #endif 3682 } 3683 3684 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3685 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3686 memcpy(ec_qx, qx, 32); 3687 memcpy(ec_qy, qy, 32); 3688 memcpy(ec_d, d, 32); 3689 sm_have_ec_keypair = 1; 3690 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3691 #endif 3692 } 3693 3694 void sm_test_use_fixed_ec_keypair(void){ 3695 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3696 #ifdef USE_MBEDTLS_FOR_ECDH 3697 // use test keypair from spec 3698 mbedtls_mpi x; 3699 mbedtls_mpi_init(&x); 3700 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3701 mbedtls_mpi_write_binary(&x, ec_d, 32); 3702 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3703 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3704 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3705 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3706 mbedtls_mpi_free(&x); 3707 #endif 3708 sm_have_ec_keypair = 1; 3709 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3710 #endif 3711 } 3712 3713 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3714 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3715 if (!hci_con) return NULL; 3716 return &hci_con->sm_connection; 3717 } 3718 3719 // @returns 0 if not encrypted, 7-16 otherwise 3720 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3721 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3722 if (!sm_conn) return 0; // wrong connection 3723 if (!sm_conn->sm_connection_encrypted) return 0; 3724 return sm_conn->sm_actual_encryption_key_size; 3725 } 3726 3727 int sm_authenticated(hci_con_handle_t con_handle){ 3728 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3729 if (!sm_conn) return 0; // wrong connection 3730 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3731 return sm_conn->sm_connection_authenticated; 3732 } 3733 3734 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3735 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3736 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3737 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3738 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3739 return sm_conn->sm_connection_authorization_state; 3740 } 3741 3742 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3743 switch (sm_conn->sm_engine_state){ 3744 case SM_GENERAL_IDLE: 3745 case SM_RESPONDER_IDLE: 3746 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3747 sm_run(); 3748 break; 3749 default: 3750 break; 3751 } 3752 } 3753 3754 /** 3755 * @brief Trigger Security Request 3756 */ 3757 void sm_send_security_request(hci_con_handle_t con_handle){ 3758 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3759 if (!sm_conn) return; 3760 sm_send_security_request_for_connection(sm_conn); 3761 } 3762 3763 // request pairing 3764 void sm_request_pairing(hci_con_handle_t con_handle){ 3765 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3766 if (!sm_conn) return; // wrong connection 3767 3768 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3769 if (sm_conn->sm_role){ 3770 sm_send_security_request_for_connection(sm_conn); 3771 } else { 3772 // used as a trigger to start central/master/initiator security procedures 3773 uint16_t ediv; 3774 sm_key_t ltk; 3775 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3776 switch (sm_conn->sm_irk_lookup_state){ 3777 case IRK_LOOKUP_FAILED: 3778 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3779 break; 3780 case IRK_LOOKUP_SUCCEEDED: 3781 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3782 if (!sm_is_null_key(ltk) || ediv){ 3783 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3784 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3785 } else { 3786 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3787 } 3788 break; 3789 default: 3790 sm_conn->sm_bonding_requested = 1; 3791 break; 3792 } 3793 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3794 sm_conn->sm_bonding_requested = 1; 3795 } 3796 } 3797 sm_run(); 3798 } 3799 3800 // called by client app on authorization request 3801 void sm_authorization_decline(hci_con_handle_t con_handle){ 3802 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3803 if (!sm_conn) return; // wrong connection 3804 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3805 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3806 } 3807 3808 void sm_authorization_grant(hci_con_handle_t con_handle){ 3809 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3810 if (!sm_conn) return; // wrong connection 3811 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3812 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3813 } 3814 3815 // GAP Bonding API 3816 3817 void sm_bonding_decline(hci_con_handle_t con_handle){ 3818 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3819 if (!sm_conn) return; // wrong connection 3820 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3821 3822 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3823 switch (setup->sm_stk_generation_method){ 3824 case PK_RESP_INPUT: 3825 case PK_INIT_INPUT: 3826 case OK_BOTH_INPUT: 3827 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3828 break; 3829 case NK_BOTH_INPUT: 3830 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3831 break; 3832 case JUST_WORKS: 3833 case OOB: 3834 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3835 break; 3836 } 3837 } 3838 sm_run(); 3839 } 3840 3841 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3842 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3843 if (!sm_conn) return; // wrong connection 3844 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3845 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3846 if (setup->sm_use_secure_connections){ 3847 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3848 } else { 3849 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3850 } 3851 } 3852 3853 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3854 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3855 sm_sc_prepare_dhkey_check(sm_conn); 3856 } 3857 #endif 3858 3859 sm_run(); 3860 } 3861 3862 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3863 // for now, it's the same 3864 sm_just_works_confirm(con_handle); 3865 } 3866 3867 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3868 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3869 if (!sm_conn) return; // wrong connection 3870 sm_reset_tk(); 3871 big_endian_store_32(setup->sm_tk, 12, passkey); 3872 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3873 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3874 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3875 } 3876 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3877 memcpy(setup->sm_ra, setup->sm_tk, 16); 3878 memcpy(setup->sm_rb, setup->sm_tk, 16); 3879 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3880 sm_sc_start_calculating_local_confirm(sm_conn); 3881 } 3882 #endif 3883 sm_run(); 3884 } 3885 3886 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3887 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3888 if (!sm_conn) return; // wrong connection 3889 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3890 setup->sm_keypress_notification = action; 3891 sm_run(); 3892 } 3893 3894 /** 3895 * @brief Identify device in LE Device DB 3896 * @param handle 3897 * @returns index from le_device_db or -1 if not found/identified 3898 */ 3899 int sm_le_device_index(hci_con_handle_t con_handle ){ 3900 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3901 if (!sm_conn) return -1; 3902 return sm_conn->sm_le_db_index; 3903 } 3904 3905 static int gap_random_address_type_requires_updates(void){ 3906 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3907 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 3908 return 1; 3909 } 3910 static uint8_t own_address_type(void){ 3911 if (gap_random_adress_type == 0) return 0; 3912 return 1; 3913 } 3914 3915 // GAP LE API 3916 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3917 gap_random_address_update_stop(); 3918 gap_random_adress_type = random_address_type; 3919 hci_le_advertisements_set_own_address_type(own_address_type()); 3920 if (!gap_random_address_type_requires_updates()) return; 3921 gap_random_address_update_start(); 3922 gap_random_address_trigger(); 3923 } 3924 3925 gap_random_address_type_t gap_random_address_get_mode(void){ 3926 return gap_random_adress_type; 3927 } 3928 3929 void gap_random_address_set_update_period(int period_ms){ 3930 gap_random_adress_update_period = period_ms; 3931 if (!gap_random_address_type_requires_updates()) return; 3932 gap_random_address_update_stop(); 3933 gap_random_address_update_start(); 3934 } 3935 3936 void gap_random_address_set(bd_addr_t addr){ 3937 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 3938 memcpy(sm_random_address, addr, 6); 3939 if (rau_state == RAU_W4_WORKING) return; 3940 rau_state = RAU_SET_ADDRESS; 3941 sm_run(); 3942 } 3943 3944 /* 3945 * @brief Set Advertisement Paramters 3946 * @param adv_int_min 3947 * @param adv_int_max 3948 * @param adv_type 3949 * @param direct_address_type 3950 * @param direct_address 3951 * @param channel_map 3952 * @param filter_policy 3953 * 3954 * @note own_address_type is used from gap_random_address_set_mode 3955 */ 3956 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3957 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3958 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, own_address_type(), 3959 direct_address_typ, direct_address, channel_map, filter_policy); 3960 } 3961 3962