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