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