1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 55 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 56 #else 57 #define USE_MBEDTLS_FOR_ECDH 58 #endif 59 #endif 60 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #include "mbedtls/config.h" 65 #include "mbedtls/platform.h" 66 #include "mbedtls/ecp.h" 67 #include "sm_mbedtls_allocator.h" 68 #endif 69 70 // 71 // SM internal types and globals 72 // 73 74 typedef enum { 75 DKG_W4_WORKING, 76 DKG_CALC_IRK, 77 DKG_W4_IRK, 78 DKG_CALC_DHK, 79 DKG_W4_DHK, 80 DKG_READY 81 } derived_key_generation_t; 82 83 typedef enum { 84 RAU_W4_WORKING, 85 RAU_IDLE, 86 RAU_GET_RANDOM, 87 RAU_W4_RANDOM, 88 RAU_GET_ENC, 89 RAU_W4_ENC, 90 RAU_SET_ADDRESS, 91 } random_address_update_t; 92 93 typedef enum { 94 CMAC_IDLE, 95 CMAC_CALC_SUBKEYS, 96 CMAC_W4_SUBKEYS, 97 CMAC_CALC_MI, 98 CMAC_W4_MI, 99 CMAC_CALC_MLAST, 100 CMAC_W4_MLAST 101 } cmac_state_t; 102 103 typedef enum { 104 JUST_WORKS, 105 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 106 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 107 OK_BOTH_INPUT, // Only input on both, both input PK 108 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 109 OOB // OOB available on both sides 110 } stk_generation_method_t; 111 112 typedef enum { 113 SM_USER_RESPONSE_IDLE, 114 SM_USER_RESPONSE_PENDING, 115 SM_USER_RESPONSE_CONFIRM, 116 SM_USER_RESPONSE_PASSKEY, 117 SM_USER_RESPONSE_DECLINE 118 } sm_user_response_t; 119 120 typedef enum { 121 SM_AES128_IDLE, 122 SM_AES128_ACTIVE 123 } sm_aes128_state_t; 124 125 typedef enum { 126 ADDRESS_RESOLUTION_IDLE, 127 ADDRESS_RESOLUTION_GENERAL, 128 ADDRESS_RESOLUTION_FOR_CONNECTION, 129 } address_resolution_mode_t; 130 131 typedef enum { 132 ADDRESS_RESOLUTION_SUCEEDED, 133 ADDRESS_RESOLUTION_FAILED, 134 } address_resolution_event_t; 135 136 typedef enum { 137 EC_KEY_GENERATION_IDLE, 138 EC_KEY_GENERATION_ACTIVE, 139 EC_KEY_GENERATION_DONE, 140 } ec_key_generation_state_t; 141 142 typedef enum { 143 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 144 } sm_state_var_t; 145 146 // 147 // GLOBAL DATA 148 // 149 150 static uint8_t test_use_fixed_local_csrk; 151 152 // configuration 153 static uint8_t sm_accepted_stk_generation_methods; 154 static uint8_t sm_max_encryption_key_size; 155 static uint8_t sm_min_encryption_key_size; 156 static uint8_t sm_auth_req = 0; 157 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 158 static uint8_t sm_slave_request_security; 159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 160 static uint8_t sm_have_ec_keypair; 161 #endif 162 163 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 164 static sm_key_t sm_persistent_er; 165 static sm_key_t sm_persistent_ir; 166 167 // derived from sm_persistent_ir 168 static sm_key_t sm_persistent_dhk; 169 static sm_key_t sm_persistent_irk; 170 static uint8_t sm_persistent_irk_ready = 0; // used for testing 171 static derived_key_generation_t dkg_state; 172 173 // derived from sm_persistent_er 174 // .. 175 176 // random address update 177 static random_address_update_t rau_state; 178 static bd_addr_t sm_random_address; 179 180 // CMAC Calculation: General 181 static cmac_state_t sm_cmac_state; 182 static uint16_t sm_cmac_message_len; 183 static sm_key_t sm_cmac_k; 184 static sm_key_t sm_cmac_x; 185 static sm_key_t sm_cmac_m_last; 186 static uint8_t sm_cmac_block_current; 187 static uint8_t sm_cmac_block_count; 188 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 189 static void (*sm_cmac_done_handler)(uint8_t * hash); 190 191 // CMAC for ATT Signed Writes 192 static uint8_t sm_cmac_header[3]; 193 static const uint8_t * sm_cmac_message; 194 static uint8_t sm_cmac_sign_counter[4]; 195 196 // CMAC for Secure Connection functions 197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 198 static sm_connection_t * sm_cmac_connection; 199 static uint8_t sm_cmac_sc_buffer[80]; 200 #endif 201 202 // resolvable private address lookup / CSRK calculation 203 static int sm_address_resolution_test; 204 static int sm_address_resolution_ah_calculation_active; 205 static uint8_t sm_address_resolution_addr_type; 206 static bd_addr_t sm_address_resolution_address; 207 static void * sm_address_resolution_context; 208 static address_resolution_mode_t sm_address_resolution_mode; 209 static btstack_linked_list_t sm_address_resolution_general_queue; 210 211 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 212 static sm_aes128_state_t sm_aes128_state; 213 static void * sm_aes128_context; 214 215 // random engine. store context (ususally sm_connection_t) 216 static void * sm_random_context; 217 218 // to receive hci events 219 static btstack_packet_callback_registration_t hci_event_callback_registration; 220 221 /* to dispatch sm event */ 222 static btstack_linked_list_t sm_event_handlers; 223 224 225 // Software ECDH implementation provided by mbedtls 226 #ifdef USE_MBEDTLS_FOR_ECDH 227 // group is always valid 228 static mbedtls_ecp_group mbedtls_ec_group; 229 static ec_key_generation_state_t ec_key_generation_state; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 static uint8_t ec_d[32]; 233 #ifndef HAVE_MALLOC 234 // COMP Method with Window 2 235 // 1300 bytes with 23 allocations 236 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 237 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 238 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 239 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 240 #endif 241 #endif 242 243 // 244 // Volume 3, Part H, Chapter 24 245 // "Security shall be initiated by the Security Manager in the device in the master role. 246 // The device in the slave role shall be the responding device." 247 // -> master := initiator, slave := responder 248 // 249 250 // data needed for security setup 251 typedef struct sm_setup_context { 252 253 btstack_timer_source_t sm_timeout; 254 255 // used in all phases 256 uint8_t sm_pairing_failed_reason; 257 258 // user response, (Phase 1 and/or 2) 259 uint8_t sm_user_response; 260 uint8_t sm_keypress_notification; 261 262 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 263 int sm_key_distribution_send_set; 264 int sm_key_distribution_received_set; 265 266 // Phase 2 (Pairing over SMP) 267 stk_generation_method_t sm_stk_generation_method; 268 sm_key_t sm_tk; 269 uint8_t sm_use_secure_connections; 270 271 sm_key_t sm_c1_t3_value; // c1 calculation 272 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 273 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 274 sm_key_t sm_local_random; 275 sm_key_t sm_local_confirm; 276 sm_key_t sm_peer_random; 277 sm_key_t sm_peer_confirm; 278 uint8_t sm_m_addr_type; // address and type can be removed 279 uint8_t sm_s_addr_type; // '' 280 bd_addr_t sm_m_address; // '' 281 bd_addr_t sm_s_address; // '' 282 sm_key_t sm_ltk; 283 284 uint8_t sm_state_vars; 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 287 uint8_t sm_peer_qy[32]; // '' 288 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 289 sm_key_t sm_local_nonce; // might be combined with sm_local_random 290 sm_key_t sm_peer_dhkey_check; 291 sm_key_t sm_local_dhkey_check; 292 sm_key_t sm_ra; 293 sm_key_t sm_rb; 294 sm_key_t sm_t; // used for f5 and h6 295 sm_key_t sm_mackey; 296 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 297 #endif 298 299 // Phase 3 300 301 // key distribution, we generate 302 uint16_t sm_local_y; 303 uint16_t sm_local_div; 304 uint16_t sm_local_ediv; 305 uint8_t sm_local_rand[8]; 306 sm_key_t sm_local_ltk; 307 sm_key_t sm_local_csrk; 308 sm_key_t sm_local_irk; 309 // sm_local_address/addr_type not needed 310 311 // key distribution, received from peer 312 uint16_t sm_peer_y; 313 uint16_t sm_peer_div; 314 uint16_t sm_peer_ediv; 315 uint8_t sm_peer_rand[8]; 316 sm_key_t sm_peer_ltk; 317 sm_key_t sm_peer_irk; 318 sm_key_t sm_peer_csrk; 319 uint8_t sm_peer_addr_type; 320 bd_addr_t sm_peer_address; 321 322 } sm_setup_context_t; 323 324 // 325 static sm_setup_context_t the_setup; 326 static sm_setup_context_t * setup = &the_setup; 327 328 // active connection - the one for which the_setup is used for 329 static uint16_t sm_active_connection = 0; 330 331 // @returns 1 if oob data is available 332 // stores oob data in provided 16 byte buffer if not null 333 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 334 335 // horizontal: initiator capabilities 336 // vertial: responder capabilities 337 static const stk_generation_method_t stk_generation_method [5] [5] = { 338 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 339 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 340 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 341 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 342 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 343 }; 344 345 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 346 #ifdef ENABLE_LE_SECURE_CONNECTIONS 347 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 348 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 349 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 350 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 351 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 352 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 353 }; 354 #endif 355 356 static void sm_run(void); 357 static void sm_done_for_handle(hci_con_handle_t con_handle); 358 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 359 static inline int sm_calc_actual_encryption_key_size(int other); 360 static int sm_validate_stk_generation_method(void); 361 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 362 363 static void log_info_hex16(const char * name, uint16_t value){ 364 log_info("%-6s 0x%04x", name, value); 365 } 366 367 // @returns 1 if all bytes are 0 368 static int sm_is_null(uint8_t * data, int size){ 369 int i; 370 for (i=0; i < size ; i++){ 371 if (data[i]) return 0; 372 } 373 return 1; 374 } 375 376 static int sm_is_null_random(uint8_t random[8]){ 377 return sm_is_null(random, 8); 378 } 379 380 static int sm_is_null_key(uint8_t * key){ 381 return sm_is_null(key, 16); 382 } 383 384 // Key utils 385 static void sm_reset_tk(void){ 386 int i; 387 for (i=0;i<16;i++){ 388 setup->sm_tk[i] = 0; 389 } 390 } 391 392 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 393 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 394 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 395 int i; 396 for (i = max_encryption_size ; i < 16 ; i++){ 397 key[15-i] = 0; 398 } 399 } 400 401 // SMP Timeout implementation 402 403 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 404 // the Security Manager Timer shall be reset and started. 405 // 406 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 407 // 408 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 409 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 410 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 411 // established. 412 413 static void sm_timeout_handler(btstack_timer_source_t * timer){ 414 log_info("SM timeout"); 415 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 416 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 417 sm_done_for_handle(sm_conn->sm_handle); 418 419 // trigger handling of next ready connection 420 sm_run(); 421 } 422 static void sm_timeout_start(sm_connection_t * sm_conn){ 423 btstack_run_loop_remove_timer(&setup->sm_timeout); 424 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 425 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 426 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 427 btstack_run_loop_add_timer(&setup->sm_timeout); 428 } 429 static void sm_timeout_stop(void){ 430 btstack_run_loop_remove_timer(&setup->sm_timeout); 431 } 432 static void sm_timeout_reset(sm_connection_t * sm_conn){ 433 sm_timeout_stop(); 434 sm_timeout_start(sm_conn); 435 } 436 437 // end of sm timeout 438 439 // GAP Random Address updates 440 static gap_random_address_type_t gap_random_adress_type; 441 static btstack_timer_source_t gap_random_address_update_timer; 442 static uint32_t gap_random_adress_update_period; 443 444 static void gap_random_address_trigger(void){ 445 if (rau_state != RAU_IDLE) return; 446 log_info("gap_random_address_trigger"); 447 rau_state = RAU_GET_RANDOM; 448 sm_run(); 449 } 450 451 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 452 log_info("GAP Random Address Update due"); 453 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 454 btstack_run_loop_add_timer(&gap_random_address_update_timer); 455 gap_random_address_trigger(); 456 } 457 458 static void gap_random_address_update_start(void){ 459 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 460 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 461 btstack_run_loop_add_timer(&gap_random_address_update_timer); 462 } 463 464 static void gap_random_address_update_stop(void){ 465 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 466 } 467 468 469 static void sm_random_start(void * context){ 470 sm_random_context = context; 471 hci_send_cmd(&hci_le_rand); 472 } 473 474 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 475 // context is made availabe to aes128 result handler by this 476 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 477 sm_aes128_state = SM_AES128_ACTIVE; 478 sm_key_t key_flipped, plaintext_flipped; 479 reverse_128(key, key_flipped); 480 reverse_128(plaintext, plaintext_flipped); 481 sm_aes128_context = context; 482 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 483 } 484 485 // ah(k,r) helper 486 // r = padding || r 487 // r - 24 bit value 488 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 489 // r'= padding || r 490 memset(r_prime, 0, 16); 491 memcpy(&r_prime[13], r, 3); 492 } 493 494 // d1 helper 495 // d' = padding || r || d 496 // d,r - 16 bit values 497 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 498 // d'= padding || r || d 499 memset(d1_prime, 0, 16); 500 big_endian_store_16(d1_prime, 12, r); 501 big_endian_store_16(d1_prime, 14, d); 502 } 503 504 // dm helper 505 // r’ = padding || r 506 // r - 64 bit value 507 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 508 memset(r_prime, 0, 16); 509 memcpy(&r_prime[8], r, 8); 510 } 511 512 // calculate arguments for first AES128 operation in C1 function 513 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 514 515 // p1 = pres || preq || rat’ || iat’ 516 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 517 // cant octet of pres becomes the most significant octet of p1. 518 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 519 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 520 // p1 is 0x05000800000302070710000001010001." 521 522 sm_key_t p1; 523 reverse_56(pres, &p1[0]); 524 reverse_56(preq, &p1[7]); 525 p1[14] = rat; 526 p1[15] = iat; 527 log_info_key("p1", p1); 528 log_info_key("r", r); 529 530 // t1 = r xor p1 531 int i; 532 for (i=0;i<16;i++){ 533 t1[i] = r[i] ^ p1[i]; 534 } 535 log_info_key("t1", t1); 536 } 537 538 // calculate arguments for second AES128 operation in C1 function 539 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 540 // p2 = padding || ia || ra 541 // "The least significant octet of ra becomes the least significant octet of p2 and 542 // the most significant octet of padding becomes the most significant octet of p2. 543 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 544 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 545 546 sm_key_t p2; 547 memset(p2, 0, 16); 548 memcpy(&p2[4], ia, 6); 549 memcpy(&p2[10], ra, 6); 550 log_info_key("p2", p2); 551 552 // c1 = e(k, t2_xor_p2) 553 int i; 554 for (i=0;i<16;i++){ 555 t3[i] = t2[i] ^ p2[i]; 556 } 557 log_info_key("t3", t3); 558 } 559 560 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 561 log_info_key("r1", r1); 562 log_info_key("r2", r2); 563 memcpy(&r_prime[8], &r2[8], 8); 564 memcpy(&r_prime[0], &r1[8], 8); 565 } 566 567 #ifdef ENABLE_LE_SECURE_CONNECTIONS 568 // Software implementations of crypto toolbox for LE Secure Connection 569 // TODO: replace with code to use AES Engine of HCI Controller 570 typedef uint8_t sm_key24_t[3]; 571 typedef uint8_t sm_key56_t[7]; 572 typedef uint8_t sm_key256_t[32]; 573 574 #if 0 575 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 576 uint32_t rk[RKLENGTH(KEYBITS)]; 577 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 578 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 579 } 580 581 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 582 memcpy(k1, k0, 16); 583 sm_shift_left_by_one_bit_inplace(16, k1); 584 if (k0[0] & 0x80){ 585 k1[15] ^= 0x87; 586 } 587 memcpy(k2, k1, 16); 588 sm_shift_left_by_one_bit_inplace(16, k2); 589 if (k1[0] & 0x80){ 590 k2[15] ^= 0x87; 591 } 592 } 593 594 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 595 sm_key_t k0, k1, k2, zero; 596 memset(zero, 0, 16); 597 598 aes128_calc_cyphertext(key, zero, k0); 599 calc_subkeys(k0, k1, k2); 600 601 int cmac_block_count = (cmac_message_len + 15) / 16; 602 603 // step 3: .. 604 if (cmac_block_count==0){ 605 cmac_block_count = 1; 606 } 607 608 // step 4: set m_last 609 sm_key_t cmac_m_last; 610 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 611 int i; 612 if (sm_cmac_last_block_complete){ 613 for (i=0;i<16;i++){ 614 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 615 } 616 } else { 617 int valid_octets_in_last_block = cmac_message_len & 0x0f; 618 for (i=0;i<16;i++){ 619 if (i < valid_octets_in_last_block){ 620 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 621 continue; 622 } 623 if (i == valid_octets_in_last_block){ 624 cmac_m_last[i] = 0x80 ^ k2[i]; 625 continue; 626 } 627 cmac_m_last[i] = k2[i]; 628 } 629 } 630 631 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 632 // LOG_KEY(cmac_m_last); 633 634 // Step 5 635 sm_key_t cmac_x; 636 memset(cmac_x, 0, 16); 637 638 // Step 6 639 sm_key_t sm_cmac_y; 640 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 641 for (i=0;i<16;i++){ 642 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 643 } 644 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 645 } 646 for (i=0;i<16;i++){ 647 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 648 } 649 650 // Step 7 651 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 652 } 653 #endif 654 #endif 655 656 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 657 event[0] = type; 658 event[1] = event_size - 2; 659 little_endian_store_16(event, 2, con_handle); 660 event[4] = addr_type; 661 reverse_bd_addr(address, &event[5]); 662 } 663 664 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 665 // dispatch to all event handlers 666 btstack_linked_list_iterator_t it; 667 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 668 while (btstack_linked_list_iterator_has_next(&it)){ 669 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 670 entry->callback(packet_type, 0, packet, size); 671 } 672 } 673 674 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 675 uint8_t event[11]; 676 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 677 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 678 } 679 680 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 681 uint8_t event[15]; 682 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 683 little_endian_store_32(event, 11, passkey); 684 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 685 } 686 687 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 688 uint8_t event[13]; 689 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 690 little_endian_store_16(event, 11, index); 691 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 692 } 693 694 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 695 696 uint8_t event[18]; 697 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 698 event[11] = result; 699 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 700 } 701 702 // decide on stk generation based on 703 // - pairing request 704 // - io capabilities 705 // - OOB data availability 706 static void sm_setup_tk(void){ 707 708 // default: just works 709 setup->sm_stk_generation_method = JUST_WORKS; 710 711 #ifdef ENABLE_LE_SECURE_CONNECTIONS 712 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 713 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 714 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 715 memset(setup->sm_ra, 0, 16); 716 memset(setup->sm_rb, 0, 16); 717 #else 718 setup->sm_use_secure_connections = 0; 719 #endif 720 721 // If both devices have not set the MITM option in the Authentication Requirements 722 // Flags, then the IO capabilities shall be ignored and the Just Works association 723 // model shall be used. 724 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 725 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 726 log_info("SM: MITM not required by both -> JUST WORKS"); 727 return; 728 } 729 730 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 731 732 // If both devices have out of band authentication data, then the Authentication 733 // Requirements Flags shall be ignored when selecting the pairing method and the 734 // Out of Band pairing method shall be used. 735 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 736 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 737 log_info("SM: have OOB data"); 738 log_info_key("OOB", setup->sm_tk); 739 setup->sm_stk_generation_method = OOB; 740 return; 741 } 742 743 // Reset TK as it has been setup in sm_init_setup 744 sm_reset_tk(); 745 746 // Also use just works if unknown io capabilites 747 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 748 return; 749 } 750 751 // Otherwise the IO capabilities of the devices shall be used to determine the 752 // pairing method as defined in Table 2.4. 753 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 754 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 755 756 #ifdef ENABLE_LE_SECURE_CONNECTIONS 757 // table not define by default 758 if (setup->sm_use_secure_connections){ 759 generation_method = stk_generation_method_with_secure_connection; 760 } 761 #endif 762 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 763 764 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 765 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 766 } 767 768 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 769 int flags = 0; 770 if (key_set & SM_KEYDIST_ENC_KEY){ 771 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 772 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 773 } 774 if (key_set & SM_KEYDIST_ID_KEY){ 775 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 776 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 777 } 778 if (key_set & SM_KEYDIST_SIGN){ 779 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 780 } 781 return flags; 782 } 783 784 static void sm_setup_key_distribution(uint8_t key_set){ 785 setup->sm_key_distribution_received_set = 0; 786 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 787 } 788 789 // CSRK Key Lookup 790 791 792 static int sm_address_resolution_idle(void){ 793 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 794 } 795 796 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 797 memcpy(sm_address_resolution_address, addr, 6); 798 sm_address_resolution_addr_type = addr_type; 799 sm_address_resolution_test = 0; 800 sm_address_resolution_mode = mode; 801 sm_address_resolution_context = context; 802 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 803 } 804 805 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 806 // check if already in list 807 btstack_linked_list_iterator_t it; 808 sm_lookup_entry_t * entry; 809 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 810 while(btstack_linked_list_iterator_has_next(&it)){ 811 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 812 if (entry->address_type != address_type) continue; 813 if (memcmp(entry->address, address, 6)) continue; 814 // already in list 815 return BTSTACK_BUSY; 816 } 817 entry = btstack_memory_sm_lookup_entry_get(); 818 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 819 entry->address_type = (bd_addr_type_t) address_type; 820 memcpy(entry->address, address, 6); 821 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 822 sm_run(); 823 return 0; 824 } 825 826 // CMAC Implementation using AES128 engine 827 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 828 int i; 829 int carry = 0; 830 for (i=len-1; i >= 0 ; i--){ 831 int new_carry = data[i] >> 7; 832 data[i] = data[i] << 1 | carry; 833 carry = new_carry; 834 } 835 } 836 837 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 838 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 839 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 840 } 841 static inline void dkg_next_state(void){ 842 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 843 } 844 static inline void rau_next_state(void){ 845 rau_state = (random_address_update_t) (((int)rau_state) + 1); 846 } 847 848 // CMAC calculation using AES Engine 849 850 static inline void sm_cmac_next_state(void){ 851 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 852 } 853 854 static int sm_cmac_last_block_complete(void){ 855 if (sm_cmac_message_len == 0) return 0; 856 return (sm_cmac_message_len & 0x0f) == 0; 857 } 858 859 int sm_cmac_ready(void){ 860 return sm_cmac_state == CMAC_IDLE; 861 } 862 863 // generic cmac calculation 864 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 865 // Generalized CMAC 866 memcpy(sm_cmac_k, key, 16); 867 memset(sm_cmac_x, 0, 16); 868 sm_cmac_block_current = 0; 869 sm_cmac_message_len = message_len; 870 sm_cmac_done_handler = done_callback; 871 sm_cmac_get_byte = get_byte_callback; 872 873 // step 2: n := ceil(len/const_Bsize); 874 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 875 876 // step 3: .. 877 if (sm_cmac_block_count==0){ 878 sm_cmac_block_count = 1; 879 } 880 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 881 882 // first, we need to compute l for k1, k2, and m_last 883 sm_cmac_state = CMAC_CALC_SUBKEYS; 884 885 // let's go 886 sm_run(); 887 } 888 889 // cmac for ATT Message signing 890 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 891 if (offset >= sm_cmac_message_len) { 892 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 893 return 0; 894 } 895 896 offset = sm_cmac_message_len - 1 - offset; 897 898 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 899 if (offset < 3){ 900 return sm_cmac_header[offset]; 901 } 902 int actual_message_len_incl_header = sm_cmac_message_len - 4; 903 if (offset < actual_message_len_incl_header){ 904 return sm_cmac_message[offset - 3]; 905 } 906 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 907 } 908 909 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 910 // ATT Message Signing 911 sm_cmac_header[0] = opcode; 912 little_endian_store_16(sm_cmac_header, 1, con_handle); 913 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 914 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 915 sm_cmac_message = message; 916 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 917 } 918 919 920 static void sm_cmac_handle_aes_engine_ready(void){ 921 switch (sm_cmac_state){ 922 case CMAC_CALC_SUBKEYS: { 923 sm_key_t const_zero; 924 memset(const_zero, 0, 16); 925 sm_cmac_next_state(); 926 sm_aes128_start(sm_cmac_k, const_zero, NULL); 927 break; 928 } 929 case CMAC_CALC_MI: { 930 int j; 931 sm_key_t y; 932 for (j=0;j<16;j++){ 933 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 934 } 935 sm_cmac_block_current++; 936 sm_cmac_next_state(); 937 sm_aes128_start(sm_cmac_k, y, NULL); 938 break; 939 } 940 case CMAC_CALC_MLAST: { 941 int i; 942 sm_key_t y; 943 for (i=0;i<16;i++){ 944 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 945 } 946 log_info_key("Y", y); 947 sm_cmac_block_current++; 948 sm_cmac_next_state(); 949 sm_aes128_start(sm_cmac_k, y, NULL); 950 break; 951 } 952 default: 953 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 954 break; 955 } 956 } 957 958 static void sm_cmac_handle_encryption_result(sm_key_t data){ 959 switch (sm_cmac_state){ 960 case CMAC_W4_SUBKEYS: { 961 sm_key_t k1; 962 memcpy(k1, data, 16); 963 sm_shift_left_by_one_bit_inplace(16, k1); 964 if (data[0] & 0x80){ 965 k1[15] ^= 0x87; 966 } 967 sm_key_t k2; 968 memcpy(k2, k1, 16); 969 sm_shift_left_by_one_bit_inplace(16, k2); 970 if (k1[0] & 0x80){ 971 k2[15] ^= 0x87; 972 } 973 974 log_info_key("k", sm_cmac_k); 975 log_info_key("k1", k1); 976 log_info_key("k2", k2); 977 978 // step 4: set m_last 979 int i; 980 if (sm_cmac_last_block_complete()){ 981 for (i=0;i<16;i++){ 982 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 983 } 984 } else { 985 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 986 for (i=0;i<16;i++){ 987 if (i < valid_octets_in_last_block){ 988 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 989 continue; 990 } 991 if (i == valid_octets_in_last_block){ 992 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 993 continue; 994 } 995 sm_cmac_m_last[i] = k2[i]; 996 } 997 } 998 999 // next 1000 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1001 break; 1002 } 1003 case CMAC_W4_MI: 1004 memcpy(sm_cmac_x, data, 16); 1005 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1006 break; 1007 case CMAC_W4_MLAST: 1008 // done 1009 log_info("Setting CMAC Engine to IDLE"); 1010 sm_cmac_state = CMAC_IDLE; 1011 log_info_key("CMAC", data); 1012 sm_cmac_done_handler(data); 1013 break; 1014 default: 1015 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1016 break; 1017 } 1018 } 1019 1020 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1021 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1022 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1023 switch (setup->sm_stk_generation_method){ 1024 case PK_RESP_INPUT: 1025 if (sm_conn->sm_role){ 1026 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1027 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1028 } else { 1029 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1030 } 1031 break; 1032 case PK_INIT_INPUT: 1033 if (sm_conn->sm_role){ 1034 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1035 } else { 1036 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1037 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1038 } 1039 break; 1040 case OK_BOTH_INPUT: 1041 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1042 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1043 break; 1044 case NK_BOTH_INPUT: 1045 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1046 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1047 break; 1048 case JUST_WORKS: 1049 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1050 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1051 break; 1052 case OOB: 1053 // client already provided OOB data, let's skip notification. 1054 break; 1055 } 1056 } 1057 1058 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1059 int recv_flags; 1060 if (sm_conn->sm_role){ 1061 // slave / responder 1062 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1063 } else { 1064 // master / initiator 1065 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1066 } 1067 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1068 return recv_flags == setup->sm_key_distribution_received_set; 1069 } 1070 1071 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1072 if (sm_active_connection == con_handle){ 1073 sm_timeout_stop(); 1074 sm_active_connection = 0; 1075 log_info("sm: connection 0x%x released setup context", con_handle); 1076 } 1077 } 1078 1079 static int sm_key_distribution_flags_for_auth_req(void){ 1080 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1081 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1082 // encryption information only if bonding requested 1083 flags |= SM_KEYDIST_ENC_KEY; 1084 } 1085 return flags; 1086 } 1087 1088 static void sm_reset_setup(void){ 1089 // fill in sm setup 1090 setup->sm_state_vars = 0; 1091 setup->sm_keypress_notification = 0xff; 1092 sm_reset_tk(); 1093 } 1094 1095 static void sm_init_setup(sm_connection_t * sm_conn){ 1096 1097 // fill in sm setup 1098 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1099 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1100 1101 // query client for OOB data 1102 int have_oob_data = 0; 1103 if (sm_get_oob_data) { 1104 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1105 } 1106 1107 sm_pairing_packet_t * local_packet; 1108 if (sm_conn->sm_role){ 1109 // slave 1110 local_packet = &setup->sm_s_pres; 1111 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1112 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1113 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1114 } else { 1115 // master 1116 local_packet = &setup->sm_m_preq; 1117 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1118 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1119 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1120 1121 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1122 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1123 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1124 } 1125 1126 uint8_t auth_req = sm_auth_req; 1127 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1128 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1129 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1130 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1131 } 1132 1133 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1134 1135 sm_pairing_packet_t * remote_packet; 1136 int remote_key_request; 1137 if (sm_conn->sm_role){ 1138 // slave / responder 1139 remote_packet = &setup->sm_m_preq; 1140 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1141 } else { 1142 // master / initiator 1143 remote_packet = &setup->sm_s_pres; 1144 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1145 } 1146 1147 // check key size 1148 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1149 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1150 1151 // decide on STK generation method 1152 sm_setup_tk(); 1153 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1154 1155 // check if STK generation method is acceptable by client 1156 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1157 1158 // identical to responder 1159 sm_setup_key_distribution(remote_key_request); 1160 1161 // JUST WORKS doens't provide authentication 1162 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1163 1164 return 0; 1165 } 1166 1167 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1168 1169 // cache and reset context 1170 int matched_device_id = sm_address_resolution_test; 1171 address_resolution_mode_t mode = sm_address_resolution_mode; 1172 void * context = sm_address_resolution_context; 1173 1174 // reset context 1175 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1176 sm_address_resolution_context = NULL; 1177 sm_address_resolution_test = -1; 1178 hci_con_handle_t con_handle = 0; 1179 1180 sm_connection_t * sm_connection; 1181 sm_key_t ltk; 1182 switch (mode){ 1183 case ADDRESS_RESOLUTION_GENERAL: 1184 break; 1185 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1186 sm_connection = (sm_connection_t *) context; 1187 con_handle = sm_connection->sm_handle; 1188 switch (event){ 1189 case ADDRESS_RESOLUTION_SUCEEDED: 1190 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1191 sm_connection->sm_le_db_index = matched_device_id; 1192 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1193 if (sm_connection->sm_role) break; 1194 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1195 sm_connection->sm_security_request_received = 0; 1196 sm_connection->sm_bonding_requested = 0; 1197 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1198 if (!sm_is_null_key(ltk)){ 1199 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1200 } else { 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1202 } 1203 break; 1204 case ADDRESS_RESOLUTION_FAILED: 1205 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1206 if (sm_connection->sm_role) break; 1207 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1208 sm_connection->sm_security_request_received = 0; 1209 sm_connection->sm_bonding_requested = 0; 1210 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1211 break; 1212 } 1213 break; 1214 default: 1215 break; 1216 } 1217 1218 switch (event){ 1219 case ADDRESS_RESOLUTION_SUCEEDED: 1220 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1221 break; 1222 case ADDRESS_RESOLUTION_FAILED: 1223 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1224 break; 1225 } 1226 } 1227 1228 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1229 1230 int le_db_index = -1; 1231 1232 // lookup device based on IRK 1233 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1234 int i; 1235 for (i=0; i < le_device_db_count(); i++){ 1236 sm_key_t irk; 1237 bd_addr_t address; 1238 int address_type; 1239 le_device_db_info(i, &address_type, address, irk); 1240 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1241 log_info("sm: device found for IRK, updating"); 1242 le_db_index = i; 1243 break; 1244 } 1245 } 1246 } 1247 1248 // if not found, lookup via public address if possible 1249 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1250 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1251 int i; 1252 for (i=0; i < le_device_db_count(); i++){ 1253 bd_addr_t address; 1254 int address_type; 1255 le_device_db_info(i, &address_type, address, NULL); 1256 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1257 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1258 log_info("sm: device found for public address, updating"); 1259 le_db_index = i; 1260 break; 1261 } 1262 } 1263 } 1264 1265 // if not found, add to db 1266 if (le_db_index < 0) { 1267 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1268 } 1269 1270 if (le_db_index >= 0){ 1271 1272 // store local CSRK 1273 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1274 log_info("sm: store local CSRK"); 1275 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1276 le_device_db_local_counter_set(le_db_index, 0); 1277 } 1278 1279 // store remote CSRK 1280 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1281 log_info("sm: store remote CSRK"); 1282 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1283 le_device_db_remote_counter_set(le_db_index, 0); 1284 } 1285 1286 // store encryption information for secure connections: LTK generated by ECDH 1287 if (setup->sm_use_secure_connections){ 1288 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1289 uint8_t zero_rand[8]; 1290 memset(zero_rand, 0, 8); 1291 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1292 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1293 } 1294 1295 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1296 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1297 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1298 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1299 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1300 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1301 1302 } 1303 } 1304 1305 // keep le_db_index 1306 sm_conn->sm_le_db_index = le_db_index; 1307 } 1308 1309 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1310 setup->sm_pairing_failed_reason = reason; 1311 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1312 } 1313 1314 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1315 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1316 } 1317 1318 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1319 1320 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1321 static int sm_passkey_used(stk_generation_method_t method); 1322 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1323 1324 static void sm_log_ec_keypair(void){ 1325 log_info("Elliptic curve: d"); 1326 log_info_hexdump(ec_d,32); 1327 log_info("Elliptic curve: X"); 1328 log_info_hexdump(ec_qx,32); 1329 log_info("Elliptic curve: Y"); 1330 log_info_hexdump(ec_qy,32); 1331 } 1332 1333 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1334 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1335 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1336 } else { 1337 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1338 } 1339 } 1340 1341 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1342 if (sm_conn->sm_role){ 1343 // Responder 1344 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1345 } else { 1346 // Initiator role 1347 switch (setup->sm_stk_generation_method){ 1348 case JUST_WORKS: 1349 sm_sc_prepare_dhkey_check(sm_conn); 1350 break; 1351 1352 case NK_BOTH_INPUT: 1353 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1354 break; 1355 case PK_INIT_INPUT: 1356 case PK_RESP_INPUT: 1357 case OK_BOTH_INPUT: 1358 if (setup->sm_passkey_bit < 20) { 1359 sm_sc_start_calculating_local_confirm(sm_conn); 1360 } else { 1361 sm_sc_prepare_dhkey_check(sm_conn); 1362 } 1363 break; 1364 case OOB: 1365 // TODO: implement SC OOB 1366 break; 1367 } 1368 } 1369 } 1370 1371 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1372 return sm_cmac_sc_buffer[offset]; 1373 } 1374 1375 static void sm_sc_cmac_done(uint8_t * hash){ 1376 log_info("sm_sc_cmac_done: "); 1377 log_info_hexdump(hash, 16); 1378 1379 sm_connection_t * sm_conn = sm_cmac_connection; 1380 sm_cmac_connection = NULL; 1381 link_key_type_t link_key_type; 1382 1383 switch (sm_conn->sm_engine_state){ 1384 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1385 memcpy(setup->sm_local_confirm, hash, 16); 1386 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1387 break; 1388 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1389 // check 1390 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1391 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1392 break; 1393 } 1394 sm_sc_state_after_receiving_random(sm_conn); 1395 break; 1396 case SM_SC_W4_CALCULATE_G2: { 1397 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1398 big_endian_store_32(setup->sm_tk, 12, vab); 1399 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1400 sm_trigger_user_response(sm_conn); 1401 break; 1402 } 1403 case SM_SC_W4_CALCULATE_F5_SALT: 1404 memcpy(setup->sm_t, hash, 16); 1405 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1406 break; 1407 case SM_SC_W4_CALCULATE_F5_MACKEY: 1408 memcpy(setup->sm_mackey, hash, 16); 1409 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1410 break; 1411 case SM_SC_W4_CALCULATE_F5_LTK: 1412 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1413 // Errata Service Release to the Bluetooth Specification: ESR09 1414 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1415 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1416 memcpy(setup->sm_ltk, hash, 16); 1417 memcpy(setup->sm_local_ltk, hash, 16); 1418 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1419 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1420 break; 1421 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1422 memcpy(setup->sm_local_dhkey_check, hash, 16); 1423 if (sm_conn->sm_role){ 1424 // responder 1425 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1426 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1427 } else { 1428 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1429 } 1430 } else { 1431 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1432 } 1433 break; 1434 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1435 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1436 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1437 break; 1438 } 1439 if (sm_conn->sm_role){ 1440 // responder 1441 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1442 } else { 1443 // initiator 1444 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1445 } 1446 break; 1447 case SM_SC_W4_CALCULATE_H6_ILK: 1448 memcpy(setup->sm_t, hash, 16); 1449 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1450 break; 1451 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1452 reverse_128(hash, setup->sm_t); 1453 link_key_type = sm_conn->sm_connection_authenticated ? 1454 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1455 if (sm_conn->sm_role){ 1456 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1457 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1458 } else { 1459 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1460 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1461 } 1462 sm_done_for_handle(sm_conn->sm_handle); 1463 break; 1464 default: 1465 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1466 break; 1467 } 1468 sm_run(); 1469 } 1470 1471 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1472 const uint16_t message_len = 65; 1473 sm_cmac_connection = sm_conn; 1474 memcpy(sm_cmac_sc_buffer, u, 32); 1475 memcpy(sm_cmac_sc_buffer+32, v, 32); 1476 sm_cmac_sc_buffer[64] = z; 1477 log_info("f4 key"); 1478 log_info_hexdump(x, 16); 1479 log_info("f4 message"); 1480 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1481 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1482 } 1483 1484 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1485 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1486 static const uint8_t f5_length[] = { 0x01, 0x00}; 1487 1488 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1489 #ifdef USE_MBEDTLS_FOR_ECDH 1490 // da * Pb 1491 mbedtls_mpi d; 1492 mbedtls_ecp_point Q; 1493 mbedtls_ecp_point DH; 1494 mbedtls_mpi_init(&d); 1495 mbedtls_ecp_point_init(&Q); 1496 mbedtls_ecp_point_init(&DH); 1497 mbedtls_mpi_read_binary(&d, ec_d, 32); 1498 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1499 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1500 mbedtls_mpi_lset(&Q.Z, 1); 1501 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1502 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1503 mbedtls_ecp_point_free(&DH); 1504 mbedtls_mpi_free(&d); 1505 mbedtls_ecp_point_free(&Q); 1506 #endif 1507 log_info("dhkey"); 1508 log_info_hexdump(dhkey, 32); 1509 } 1510 1511 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1512 // calculate DHKEY 1513 sm_key256_t dhkey; 1514 sm_sc_calculate_dhkey(dhkey); 1515 1516 // calculate salt for f5 1517 const uint16_t message_len = 32; 1518 sm_cmac_connection = sm_conn; 1519 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1520 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1521 } 1522 1523 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1524 const uint16_t message_len = 53; 1525 sm_cmac_connection = sm_conn; 1526 1527 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1528 sm_cmac_sc_buffer[0] = 0; 1529 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1530 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1531 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1532 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1533 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1534 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1535 log_info("f5 key"); 1536 log_info_hexdump(t, 16); 1537 log_info("f5 message for MacKey"); 1538 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1539 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1540 } 1541 1542 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1543 sm_key56_t bd_addr_master, bd_addr_slave; 1544 bd_addr_master[0] = setup->sm_m_addr_type; 1545 bd_addr_slave[0] = setup->sm_s_addr_type; 1546 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1547 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1548 if (sm_conn->sm_role){ 1549 // responder 1550 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1551 } else { 1552 // initiator 1553 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1554 } 1555 } 1556 1557 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1558 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1559 const uint16_t message_len = 53; 1560 sm_cmac_connection = sm_conn; 1561 sm_cmac_sc_buffer[0] = 1; 1562 // 1..52 setup before 1563 log_info("f5 key"); 1564 log_info_hexdump(t, 16); 1565 log_info("f5 message for LTK"); 1566 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1567 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1568 } 1569 1570 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1571 f5_ltk(sm_conn, setup->sm_t); 1572 } 1573 1574 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1575 const uint16_t message_len = 65; 1576 sm_cmac_connection = sm_conn; 1577 memcpy(sm_cmac_sc_buffer, n1, 16); 1578 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1579 memcpy(sm_cmac_sc_buffer+32, r, 16); 1580 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1581 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1582 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1583 log_info("f6 key"); 1584 log_info_hexdump(w, 16); 1585 log_info("f6 message"); 1586 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1587 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1588 } 1589 1590 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1591 // - U is 256 bits 1592 // - V is 256 bits 1593 // - X is 128 bits 1594 // - Y is 128 bits 1595 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1596 const uint16_t message_len = 80; 1597 sm_cmac_connection = sm_conn; 1598 memcpy(sm_cmac_sc_buffer, u, 32); 1599 memcpy(sm_cmac_sc_buffer+32, v, 32); 1600 memcpy(sm_cmac_sc_buffer+64, y, 16); 1601 log_info("g2 key"); 1602 log_info_hexdump(x, 16); 1603 log_info("g2 message"); 1604 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1605 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1606 } 1607 1608 static void g2_calculate(sm_connection_t * sm_conn) { 1609 // calc Va if numeric comparison 1610 if (sm_conn->sm_role){ 1611 // responder 1612 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1613 } else { 1614 // initiator 1615 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1616 } 1617 } 1618 1619 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1620 uint8_t z = 0; 1621 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1622 // some form of passkey 1623 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1624 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1625 setup->sm_passkey_bit++; 1626 } 1627 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1628 } 1629 1630 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1631 uint8_t z = 0; 1632 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1633 // some form of passkey 1634 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1635 // sm_passkey_bit was increased before sending confirm value 1636 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1637 } 1638 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1639 } 1640 1641 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1642 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1643 } 1644 1645 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1646 // calculate DHKCheck 1647 sm_key56_t bd_addr_master, bd_addr_slave; 1648 bd_addr_master[0] = setup->sm_m_addr_type; 1649 bd_addr_slave[0] = setup->sm_s_addr_type; 1650 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1651 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1652 uint8_t iocap_a[3]; 1653 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1654 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1655 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1656 uint8_t iocap_b[3]; 1657 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1658 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1659 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1660 if (sm_conn->sm_role){ 1661 // responder 1662 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1663 } else { 1664 // initiator 1665 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1666 } 1667 } 1668 1669 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1670 // validate E = f6() 1671 sm_key56_t bd_addr_master, bd_addr_slave; 1672 bd_addr_master[0] = setup->sm_m_addr_type; 1673 bd_addr_slave[0] = setup->sm_s_addr_type; 1674 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1675 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1676 1677 uint8_t iocap_a[3]; 1678 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1679 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1680 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1681 uint8_t iocap_b[3]; 1682 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1683 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1684 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1685 if (sm_conn->sm_role){ 1686 // responder 1687 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1688 } else { 1689 // initiator 1690 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1691 } 1692 } 1693 1694 1695 // 1696 // Link Key Conversion Function h6 1697 // 1698 // h6(W, keyID) = AES-CMACW(keyID) 1699 // - W is 128 bits 1700 // - keyID is 32 bits 1701 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1702 const uint16_t message_len = 4; 1703 sm_cmac_connection = sm_conn; 1704 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1705 log_info("h6 key"); 1706 log_info_hexdump(w, 16); 1707 log_info("h6 message"); 1708 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1709 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1710 } 1711 1712 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1713 // Errata Service Release to the Bluetooth Specification: ESR09 1714 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1715 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1716 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1717 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1718 } 1719 1720 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1721 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1722 } 1723 1724 #endif 1725 1726 // key management legacy connections: 1727 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1728 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1729 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1730 // - responder reconnects: responder uses LTK receveived from master 1731 1732 // key management secure connections: 1733 // - both devices store same LTK from ECDH key exchange. 1734 1735 static void sm_load_security_info(sm_connection_t * sm_connection){ 1736 int encryption_key_size; 1737 int authenticated; 1738 int authorized; 1739 1740 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1741 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1742 &encryption_key_size, &authenticated, &authorized); 1743 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1744 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1745 sm_connection->sm_connection_authenticated = authenticated; 1746 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1747 } 1748 1749 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1750 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1751 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1752 // re-establish used key encryption size 1753 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1754 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1755 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1756 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1757 log_info("sm: received ltk request with key size %u, authenticated %u", 1758 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1759 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1760 } 1761 1762 static void sm_run(void){ 1763 1764 btstack_linked_list_iterator_t it; 1765 1766 // assert that we can send at least commands 1767 if (!hci_can_send_command_packet_now()) return; 1768 1769 // 1770 // non-connection related behaviour 1771 // 1772 1773 // distributed key generation 1774 switch (dkg_state){ 1775 case DKG_CALC_IRK: 1776 // already busy? 1777 if (sm_aes128_state == SM_AES128_IDLE) { 1778 // IRK = d1(IR, 1, 0) 1779 sm_key_t d1_prime; 1780 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1781 dkg_next_state(); 1782 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1783 return; 1784 } 1785 break; 1786 case DKG_CALC_DHK: 1787 // already busy? 1788 if (sm_aes128_state == SM_AES128_IDLE) { 1789 // DHK = d1(IR, 3, 0) 1790 sm_key_t d1_prime; 1791 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1792 dkg_next_state(); 1793 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1794 return; 1795 } 1796 break; 1797 default: 1798 break; 1799 } 1800 1801 #ifdef USE_MBEDTLS_FOR_ECDH 1802 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1803 sm_random_start(NULL); 1804 return; 1805 } 1806 #endif 1807 1808 // random address updates 1809 switch (rau_state){ 1810 case RAU_GET_RANDOM: 1811 rau_next_state(); 1812 sm_random_start(NULL); 1813 return; 1814 case RAU_GET_ENC: 1815 // already busy? 1816 if (sm_aes128_state == SM_AES128_IDLE) { 1817 sm_key_t r_prime; 1818 sm_ah_r_prime(sm_random_address, r_prime); 1819 rau_next_state(); 1820 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1821 return; 1822 } 1823 break; 1824 case RAU_SET_ADDRESS: 1825 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1826 rau_state = RAU_IDLE; 1827 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1828 return; 1829 default: 1830 break; 1831 } 1832 1833 // CMAC 1834 switch (sm_cmac_state){ 1835 case CMAC_CALC_SUBKEYS: 1836 case CMAC_CALC_MI: 1837 case CMAC_CALC_MLAST: 1838 // already busy? 1839 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1840 sm_cmac_handle_aes_engine_ready(); 1841 return; 1842 default: 1843 break; 1844 } 1845 1846 // CSRK Lookup 1847 // -- if csrk lookup ready, find connection that require csrk lookup 1848 if (sm_address_resolution_idle()){ 1849 hci_connections_get_iterator(&it); 1850 while(btstack_linked_list_iterator_has_next(&it)){ 1851 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1852 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1853 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1854 // and start lookup 1855 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1856 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1857 break; 1858 } 1859 } 1860 } 1861 1862 // -- if csrk lookup ready, resolved addresses for received addresses 1863 if (sm_address_resolution_idle()) { 1864 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1865 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1866 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1867 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1868 btstack_memory_sm_lookup_entry_free(entry); 1869 } 1870 } 1871 1872 // -- Continue with CSRK device lookup by public or resolvable private address 1873 if (!sm_address_resolution_idle()){ 1874 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1875 while (sm_address_resolution_test < le_device_db_count()){ 1876 int addr_type; 1877 bd_addr_t addr; 1878 sm_key_t irk; 1879 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1880 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1881 1882 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1883 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1884 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1885 break; 1886 } 1887 1888 if (sm_address_resolution_addr_type == 0){ 1889 sm_address_resolution_test++; 1890 continue; 1891 } 1892 1893 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1894 1895 log_info("LE Device Lookup: calculate AH"); 1896 log_info_key("IRK", irk); 1897 1898 sm_key_t r_prime; 1899 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1900 sm_address_resolution_ah_calculation_active = 1; 1901 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1902 return; 1903 } 1904 1905 if (sm_address_resolution_test >= le_device_db_count()){ 1906 log_info("LE Device Lookup: not found"); 1907 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1908 } 1909 } 1910 1911 // handle basic actions that don't requires the full context 1912 hci_connections_get_iterator(&it); 1913 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1914 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1915 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1916 switch(sm_connection->sm_engine_state){ 1917 // responder side 1918 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1919 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1920 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1921 return; 1922 1923 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1924 case SM_SC_RECEIVED_LTK_REQUEST: 1925 switch (sm_connection->sm_irk_lookup_state){ 1926 case IRK_LOOKUP_FAILED: 1927 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1928 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1929 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1930 return; 1931 default: 1932 break; 1933 } 1934 break; 1935 #endif 1936 default: 1937 break; 1938 } 1939 } 1940 1941 // 1942 // active connection handling 1943 // -- use loop to handle next connection if lock on setup context is released 1944 1945 while (1) { 1946 1947 // Find connections that requires setup context and make active if no other is locked 1948 hci_connections_get_iterator(&it); 1949 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1950 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1951 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1952 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1953 int done = 1; 1954 int err; 1955 switch (sm_connection->sm_engine_state) { 1956 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1957 // send packet if possible, 1958 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1959 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1960 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1961 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1962 } else { 1963 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1964 } 1965 // don't lock sxetup context yet 1966 done = 0; 1967 break; 1968 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1969 sm_reset_setup(); 1970 sm_init_setup(sm_connection); 1971 // recover pairing request 1972 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1973 err = sm_stk_generation_init(sm_connection); 1974 if (err){ 1975 setup->sm_pairing_failed_reason = err; 1976 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1977 break; 1978 } 1979 sm_timeout_start(sm_connection); 1980 // generate random number first, if we need to show passkey 1981 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1982 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1983 break; 1984 } 1985 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1986 break; 1987 case SM_INITIATOR_PH0_HAS_LTK: 1988 sm_reset_setup(); 1989 sm_load_security_info(sm_connection); 1990 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1991 break; 1992 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1993 sm_reset_setup(); 1994 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 1995 break; 1996 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1997 sm_reset_setup(); 1998 sm_init_setup(sm_connection); 1999 sm_timeout_start(sm_connection); 2000 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2001 break; 2002 2003 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2004 case SM_SC_RECEIVED_LTK_REQUEST: 2005 switch (sm_connection->sm_irk_lookup_state){ 2006 case IRK_LOOKUP_SUCCEEDED: 2007 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2008 // start using context by loading security info 2009 sm_reset_setup(); 2010 sm_load_security_info(sm_connection); 2011 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2012 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2013 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2014 break; 2015 } 2016 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2017 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2018 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2019 // don't lock setup context yet 2020 return; 2021 default: 2022 // just wait until IRK lookup is completed 2023 // don't lock setup context yet 2024 done = 0; 2025 break; 2026 } 2027 break; 2028 #endif 2029 default: 2030 done = 0; 2031 break; 2032 } 2033 if (done){ 2034 sm_active_connection = sm_connection->sm_handle; 2035 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2036 } 2037 } 2038 2039 // 2040 // active connection handling 2041 // 2042 2043 if (sm_active_connection == 0) return; 2044 2045 // assert that we could send a SM PDU - not needed for all of the following 2046 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2047 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2048 return; 2049 } 2050 2051 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2052 if (!connection) return; 2053 2054 // send keypress notifications 2055 if (setup->sm_keypress_notification != 0xff){ 2056 uint8_t buffer[2]; 2057 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2058 buffer[1] = setup->sm_keypress_notification; 2059 setup->sm_keypress_notification = 0xff; 2060 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2061 return; 2062 } 2063 2064 sm_key_t plaintext; 2065 int key_distribution_flags; 2066 2067 log_info("sm_run: state %u", connection->sm_engine_state); 2068 2069 switch (connection->sm_engine_state){ 2070 2071 // general 2072 case SM_GENERAL_SEND_PAIRING_FAILED: { 2073 uint8_t buffer[2]; 2074 buffer[0] = SM_CODE_PAIRING_FAILED; 2075 buffer[1] = setup->sm_pairing_failed_reason; 2076 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2077 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2078 sm_done_for_handle(connection->sm_handle); 2079 break; 2080 } 2081 2082 // responding state 2083 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2084 case SM_SC_W2_GET_RANDOM_A: 2085 sm_random_start(connection); 2086 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2087 break; 2088 case SM_SC_W2_GET_RANDOM_B: 2089 sm_random_start(connection); 2090 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2091 break; 2092 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2093 if (!sm_cmac_ready()) break; 2094 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2095 sm_sc_calculate_local_confirm(connection); 2096 break; 2097 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2098 if (!sm_cmac_ready()) break; 2099 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2100 sm_sc_calculate_remote_confirm(connection); 2101 break; 2102 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2103 if (!sm_cmac_ready()) break; 2104 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2105 sm_sc_calculate_f6_for_dhkey_check(connection); 2106 break; 2107 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2108 if (!sm_cmac_ready()) break; 2109 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2110 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2111 break; 2112 case SM_SC_W2_CALCULATE_F5_SALT: 2113 if (!sm_cmac_ready()) break; 2114 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2115 f5_calculate_salt(connection); 2116 break; 2117 case SM_SC_W2_CALCULATE_F5_MACKEY: 2118 if (!sm_cmac_ready()) break; 2119 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2120 f5_calculate_mackey(connection); 2121 break; 2122 case SM_SC_W2_CALCULATE_F5_LTK: 2123 if (!sm_cmac_ready()) break; 2124 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2125 f5_calculate_ltk(connection); 2126 break; 2127 case SM_SC_W2_CALCULATE_G2: 2128 if (!sm_cmac_ready()) break; 2129 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2130 g2_calculate(connection); 2131 break; 2132 case SM_SC_W2_CALCULATE_H6_ILK: 2133 if (!sm_cmac_ready()) break; 2134 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2135 h6_calculate_ilk(connection); 2136 break; 2137 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2138 if (!sm_cmac_ready()) break; 2139 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2140 h6_calculate_br_edr_link_key(connection); 2141 break; 2142 #endif 2143 2144 // initiator side 2145 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2146 sm_key_t peer_ltk_flipped; 2147 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2148 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2149 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2150 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2151 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2152 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2153 return; 2154 } 2155 2156 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2157 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2158 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2159 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2160 sm_timeout_reset(connection); 2161 break; 2162 2163 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2164 2165 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2166 uint8_t buffer[65]; 2167 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2168 // 2169 reverse_256(ec_qx, &buffer[1]); 2170 reverse_256(ec_qy, &buffer[33]); 2171 2172 // stk generation method 2173 // passkey entry: notify app to show passkey or to request passkey 2174 switch (setup->sm_stk_generation_method){ 2175 case JUST_WORKS: 2176 case NK_BOTH_INPUT: 2177 if (connection->sm_role){ 2178 // responder 2179 sm_sc_start_calculating_local_confirm(connection); 2180 } else { 2181 // initiator 2182 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2183 } 2184 break; 2185 case PK_INIT_INPUT: 2186 case PK_RESP_INPUT: 2187 case OK_BOTH_INPUT: 2188 // use random TK for display 2189 memcpy(setup->sm_ra, setup->sm_tk, 16); 2190 memcpy(setup->sm_rb, setup->sm_tk, 16); 2191 setup->sm_passkey_bit = 0; 2192 2193 if (connection->sm_role){ 2194 // responder 2195 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2196 } else { 2197 // initiator 2198 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2199 } 2200 sm_trigger_user_response(connection); 2201 break; 2202 case OOB: 2203 // TODO: implement SC OOB 2204 break; 2205 } 2206 2207 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2208 sm_timeout_reset(connection); 2209 break; 2210 } 2211 case SM_SC_SEND_CONFIRMATION: { 2212 uint8_t buffer[17]; 2213 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2214 reverse_128(setup->sm_local_confirm, &buffer[1]); 2215 if (connection->sm_role){ 2216 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2217 } else { 2218 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2219 } 2220 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2221 sm_timeout_reset(connection); 2222 break; 2223 } 2224 case SM_SC_SEND_PAIRING_RANDOM: { 2225 uint8_t buffer[17]; 2226 buffer[0] = SM_CODE_PAIRING_RANDOM; 2227 reverse_128(setup->sm_local_nonce, &buffer[1]); 2228 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2229 if (connection->sm_role){ 2230 // responder 2231 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2232 } else { 2233 // initiator 2234 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2235 } 2236 } else { 2237 if (connection->sm_role){ 2238 // responder 2239 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2240 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2241 } else { 2242 sm_sc_prepare_dhkey_check(connection); 2243 } 2244 } else { 2245 // initiator 2246 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2247 } 2248 } 2249 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2250 sm_timeout_reset(connection); 2251 break; 2252 } 2253 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2254 uint8_t buffer[17]; 2255 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2256 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2257 2258 if (connection->sm_role){ 2259 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2260 } else { 2261 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 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 2269 #endif 2270 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2271 // echo initiator for now 2272 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2273 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2274 2275 if (setup->sm_use_secure_connections){ 2276 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2277 // skip LTK/EDIV for SC 2278 log_info("sm: dropping encryption information flag"); 2279 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2280 } else { 2281 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2282 } 2283 2284 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); 2285 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); 2286 // update key distribution after ENC was dropped 2287 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2288 2289 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2290 sm_timeout_reset(connection); 2291 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2292 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2293 sm_trigger_user_response(connection); 2294 } 2295 return; 2296 2297 case SM_PH2_SEND_PAIRING_RANDOM: { 2298 uint8_t buffer[17]; 2299 buffer[0] = SM_CODE_PAIRING_RANDOM; 2300 reverse_128(setup->sm_local_random, &buffer[1]); 2301 if (connection->sm_role){ 2302 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2303 } else { 2304 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2305 } 2306 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2307 sm_timeout_reset(connection); 2308 break; 2309 } 2310 2311 case SM_PH2_GET_RANDOM_TK: 2312 case SM_PH2_C1_GET_RANDOM_A: 2313 case SM_PH2_C1_GET_RANDOM_B: 2314 case SM_PH3_GET_RANDOM: 2315 case SM_PH3_GET_DIV: 2316 sm_next_responding_state(connection); 2317 sm_random_start(connection); 2318 return; 2319 2320 case SM_PH2_C1_GET_ENC_B: 2321 case SM_PH2_C1_GET_ENC_D: 2322 // already busy? 2323 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2324 sm_next_responding_state(connection); 2325 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2326 return; 2327 2328 case SM_PH3_LTK_GET_ENC: 2329 case SM_RESPONDER_PH4_LTK_GET_ENC: 2330 // already busy? 2331 if (sm_aes128_state == SM_AES128_IDLE) { 2332 sm_key_t d_prime; 2333 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2334 sm_next_responding_state(connection); 2335 sm_aes128_start(sm_persistent_er, d_prime, connection); 2336 return; 2337 } 2338 break; 2339 2340 case SM_PH3_CSRK_GET_ENC: 2341 // already busy? 2342 if (sm_aes128_state == SM_AES128_IDLE) { 2343 sm_key_t d_prime; 2344 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2345 sm_next_responding_state(connection); 2346 sm_aes128_start(sm_persistent_er, d_prime, connection); 2347 return; 2348 } 2349 break; 2350 2351 case SM_PH2_C1_GET_ENC_C: 2352 // already busy? 2353 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2354 // calculate m_confirm using aes128 engine - step 1 2355 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); 2356 sm_next_responding_state(connection); 2357 sm_aes128_start(setup->sm_tk, plaintext, connection); 2358 break; 2359 case SM_PH2_C1_GET_ENC_A: 2360 // already busy? 2361 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2362 // calculate confirm using aes128 engine - step 1 2363 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); 2364 sm_next_responding_state(connection); 2365 sm_aes128_start(setup->sm_tk, plaintext, connection); 2366 break; 2367 case SM_PH2_CALC_STK: 2368 // already busy? 2369 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2370 // calculate STK 2371 if (connection->sm_role){ 2372 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2373 } else { 2374 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2375 } 2376 sm_next_responding_state(connection); 2377 sm_aes128_start(setup->sm_tk, plaintext, connection); 2378 break; 2379 case SM_PH3_Y_GET_ENC: 2380 // already busy? 2381 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2382 // PH3B2 - calculate Y from - enc 2383 // Y = dm(DHK, Rand) 2384 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2385 sm_next_responding_state(connection); 2386 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2387 return; 2388 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2389 uint8_t buffer[17]; 2390 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2391 reverse_128(setup->sm_local_confirm, &buffer[1]); 2392 if (connection->sm_role){ 2393 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2394 } else { 2395 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2396 } 2397 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2398 sm_timeout_reset(connection); 2399 return; 2400 } 2401 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2402 sm_key_t stk_flipped; 2403 reverse_128(setup->sm_ltk, stk_flipped); 2404 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2405 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2406 return; 2407 } 2408 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2409 sm_key_t stk_flipped; 2410 reverse_128(setup->sm_ltk, stk_flipped); 2411 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2412 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2413 return; 2414 } 2415 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2416 sm_key_t ltk_flipped; 2417 reverse_128(setup->sm_ltk, ltk_flipped); 2418 connection->sm_engine_state = SM_RESPONDER_IDLE; 2419 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2420 return; 2421 } 2422 case SM_RESPONDER_PH4_Y_GET_ENC: 2423 // already busy? 2424 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2425 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2426 // Y = dm(DHK, Rand) 2427 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2428 sm_next_responding_state(connection); 2429 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2430 return; 2431 2432 case SM_PH3_DISTRIBUTE_KEYS: 2433 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2434 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2435 uint8_t buffer[17]; 2436 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2437 reverse_128(setup->sm_ltk, &buffer[1]); 2438 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2439 sm_timeout_reset(connection); 2440 return; 2441 } 2442 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2443 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2444 uint8_t buffer[11]; 2445 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2446 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2447 reverse_64(setup->sm_local_rand, &buffer[3]); 2448 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2449 sm_timeout_reset(connection); 2450 return; 2451 } 2452 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2453 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2454 uint8_t buffer[17]; 2455 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2456 reverse_128(sm_persistent_irk, &buffer[1]); 2457 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2458 sm_timeout_reset(connection); 2459 return; 2460 } 2461 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2462 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2463 bd_addr_t local_address; 2464 uint8_t buffer[8]; 2465 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2466 gap_advertisements_get_address(&buffer[1], local_address); 2467 reverse_bd_addr(local_address, &buffer[2]); 2468 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2469 sm_timeout_reset(connection); 2470 return; 2471 } 2472 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2473 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2474 2475 // hack to reproduce test runs 2476 if (test_use_fixed_local_csrk){ 2477 memset(setup->sm_local_csrk, 0xcc, 16); 2478 } 2479 2480 uint8_t buffer[17]; 2481 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2482 reverse_128(setup->sm_local_csrk, &buffer[1]); 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 2488 // keys are sent 2489 if (connection->sm_role){ 2490 // slave -> receive master keys if any 2491 if (sm_key_distribution_all_received(connection)){ 2492 sm_key_distribution_handle_all_received(connection); 2493 connection->sm_engine_state = SM_RESPONDER_IDLE; 2494 sm_done_for_handle(connection->sm_handle); 2495 } else { 2496 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2497 } 2498 } else { 2499 // master -> all done 2500 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2501 sm_done_for_handle(connection->sm_handle); 2502 } 2503 break; 2504 2505 default: 2506 break; 2507 } 2508 2509 // check again if active connection was released 2510 if (sm_active_connection) break; 2511 } 2512 } 2513 2514 // note: aes engine is ready as we just got the aes result 2515 static void sm_handle_encryption_result(uint8_t * data){ 2516 2517 sm_aes128_state = SM_AES128_IDLE; 2518 2519 if (sm_address_resolution_ah_calculation_active){ 2520 sm_address_resolution_ah_calculation_active = 0; 2521 // compare calulated address against connecting device 2522 uint8_t hash[3]; 2523 reverse_24(data, hash); 2524 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2525 log_info("LE Device Lookup: matched resolvable private address"); 2526 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2527 return; 2528 } 2529 // no match, try next 2530 sm_address_resolution_test++; 2531 return; 2532 } 2533 2534 switch (dkg_state){ 2535 case DKG_W4_IRK: 2536 reverse_128(data, sm_persistent_irk); 2537 log_info_key("irk", sm_persistent_irk); 2538 dkg_next_state(); 2539 return; 2540 case DKG_W4_DHK: 2541 reverse_128(data, sm_persistent_dhk); 2542 log_info_key("dhk", sm_persistent_dhk); 2543 dkg_next_state(); 2544 // SM Init Finished 2545 return; 2546 default: 2547 break; 2548 } 2549 2550 switch (rau_state){ 2551 case RAU_W4_ENC: 2552 reverse_24(data, &sm_random_address[3]); 2553 rau_next_state(); 2554 return; 2555 default: 2556 break; 2557 } 2558 2559 switch (sm_cmac_state){ 2560 case CMAC_W4_SUBKEYS: 2561 case CMAC_W4_MI: 2562 case CMAC_W4_MLAST: 2563 { 2564 sm_key_t t; 2565 reverse_128(data, t); 2566 sm_cmac_handle_encryption_result(t); 2567 } 2568 return; 2569 default: 2570 break; 2571 } 2572 2573 // retrieve sm_connection provided to sm_aes128_start_encryption 2574 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2575 if (!connection) return; 2576 switch (connection->sm_engine_state){ 2577 case SM_PH2_C1_W4_ENC_A: 2578 case SM_PH2_C1_W4_ENC_C: 2579 { 2580 sm_key_t t2; 2581 reverse_128(data, t2); 2582 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2583 } 2584 sm_next_responding_state(connection); 2585 return; 2586 case SM_PH2_C1_W4_ENC_B: 2587 reverse_128(data, setup->sm_local_confirm); 2588 log_info_key("c1!", setup->sm_local_confirm); 2589 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2590 return; 2591 case SM_PH2_C1_W4_ENC_D: 2592 { 2593 sm_key_t peer_confirm_test; 2594 reverse_128(data, peer_confirm_test); 2595 log_info_key("c1!", peer_confirm_test); 2596 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2597 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2598 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2599 return; 2600 } 2601 if (connection->sm_role){ 2602 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2603 } else { 2604 connection->sm_engine_state = SM_PH2_CALC_STK; 2605 } 2606 } 2607 return; 2608 case SM_PH2_W4_STK: 2609 reverse_128(data, setup->sm_ltk); 2610 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2611 log_info_key("stk", setup->sm_ltk); 2612 if (connection->sm_role){ 2613 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2614 } else { 2615 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2616 } 2617 return; 2618 case SM_PH3_Y_W4_ENC:{ 2619 sm_key_t y128; 2620 reverse_128(data, y128); 2621 setup->sm_local_y = big_endian_read_16(y128, 14); 2622 log_info_hex16("y", setup->sm_local_y); 2623 // PH3B3 - calculate EDIV 2624 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2625 log_info_hex16("ediv", setup->sm_local_ediv); 2626 // PH3B4 - calculate LTK - enc 2627 // LTK = d1(ER, DIV, 0)) 2628 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2629 return; 2630 } 2631 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2632 sm_key_t y128; 2633 reverse_128(data, y128); 2634 setup->sm_local_y = big_endian_read_16(y128, 14); 2635 log_info_hex16("y", setup->sm_local_y); 2636 2637 // PH3B3 - calculate DIV 2638 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2639 log_info_hex16("ediv", setup->sm_local_ediv); 2640 // PH3B4 - calculate LTK - enc 2641 // LTK = d1(ER, DIV, 0)) 2642 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2643 return; 2644 } 2645 case SM_PH3_LTK_W4_ENC: 2646 reverse_128(data, setup->sm_ltk); 2647 log_info_key("ltk", setup->sm_ltk); 2648 // calc CSRK next 2649 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2650 return; 2651 case SM_PH3_CSRK_W4_ENC: 2652 reverse_128(data, setup->sm_local_csrk); 2653 log_info_key("csrk", setup->sm_local_csrk); 2654 if (setup->sm_key_distribution_send_set){ 2655 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2656 } else { 2657 // no keys to send, just continue 2658 if (connection->sm_role){ 2659 // slave -> receive master keys 2660 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2661 } else { 2662 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2663 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2664 } else { 2665 // master -> all done 2666 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2667 sm_done_for_handle(connection->sm_handle); 2668 } 2669 } 2670 } 2671 return; 2672 case SM_RESPONDER_PH4_LTK_W4_ENC: 2673 reverse_128(data, setup->sm_ltk); 2674 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2675 log_info_key("ltk", setup->sm_ltk); 2676 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2677 return; 2678 default: 2679 break; 2680 } 2681 } 2682 2683 #ifdef USE_MBEDTLS_FOR_ECDH 2684 2685 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2686 int offset = setup->sm_passkey_bit; 2687 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2688 while (size) { 2689 if (offset < 32){ 2690 *buffer++ = setup->sm_peer_qx[offset++]; 2691 } else { 2692 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2693 } 2694 size--; 2695 } 2696 setup->sm_passkey_bit = offset; 2697 return 0; 2698 } 2699 #endif 2700 2701 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2702 static void sm_handle_random_result(uint8_t * data){ 2703 2704 #ifdef USE_MBEDTLS_FOR_ECDH 2705 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2706 int num_bytes = setup->sm_passkey_bit; 2707 if (num_bytes < 32){ 2708 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2709 } else { 2710 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2711 } 2712 num_bytes += 8; 2713 setup->sm_passkey_bit = num_bytes; 2714 2715 if (num_bytes >= 64){ 2716 2717 // generate EC key 2718 setup->sm_passkey_bit = 0; 2719 mbedtls_mpi d; 2720 mbedtls_ecp_point P; 2721 mbedtls_mpi_init(&d); 2722 mbedtls_ecp_point_init(&P); 2723 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2724 log_info("gen keypair %x", res); 2725 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2726 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2727 mbedtls_mpi_write_binary(&d, ec_d, 32); 2728 mbedtls_ecp_point_free(&P); 2729 mbedtls_mpi_free(&d); 2730 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2731 sm_log_ec_keypair(); 2732 2733 #if 0 2734 int i; 2735 sm_key256_t dhkey; 2736 for (i=0;i<10;i++){ 2737 // printf("test dhkey check\n"); 2738 memcpy(setup->sm_peer_qx, ec_qx, 32); 2739 memcpy(setup->sm_peer_qy, ec_qy, 32); 2740 sm_sc_calculate_dhkey(dhkey); 2741 // printf("test dhkey check end\n"); 2742 } 2743 #endif 2744 2745 } 2746 } 2747 #endif 2748 2749 switch (rau_state){ 2750 case RAU_W4_RANDOM: 2751 // non-resolvable vs. resolvable 2752 switch (gap_random_adress_type){ 2753 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2754 // resolvable: use random as prand and calc address hash 2755 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2756 memcpy(sm_random_address, data, 3); 2757 sm_random_address[0] &= 0x3f; 2758 sm_random_address[0] |= 0x40; 2759 rau_state = RAU_GET_ENC; 2760 break; 2761 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2762 default: 2763 // "The two most significant bits of the address shall be equal to ‘0’"" 2764 memcpy(sm_random_address, data, 6); 2765 sm_random_address[0] &= 0x3f; 2766 rau_state = RAU_SET_ADDRESS; 2767 break; 2768 } 2769 return; 2770 default: 2771 break; 2772 } 2773 2774 // retrieve sm_connection provided to sm_random_start 2775 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2776 if (!connection) return; 2777 switch (connection->sm_engine_state){ 2778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2779 case SM_SC_W4_GET_RANDOM_A: 2780 memcpy(&setup->sm_local_nonce[0], data, 8); 2781 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2782 break; 2783 case SM_SC_W4_GET_RANDOM_B: 2784 memcpy(&setup->sm_local_nonce[8], data, 8); 2785 // initiator & jw/nc -> send pairing random 2786 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2787 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2788 break; 2789 } else { 2790 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2791 } 2792 break; 2793 #endif 2794 2795 case SM_PH2_W4_RANDOM_TK: 2796 { 2797 // map random to 0-999999 without speding much cycles on a modulus operation 2798 uint32_t tk = little_endian_read_32(data,0); 2799 tk = tk & 0xfffff; // 1048575 2800 if (tk >= 999999){ 2801 tk = tk - 999999; 2802 } 2803 sm_reset_tk(); 2804 big_endian_store_32(setup->sm_tk, 12, tk); 2805 if (connection->sm_role){ 2806 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2807 } else { 2808 if (setup->sm_use_secure_connections){ 2809 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2810 } else { 2811 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2812 sm_trigger_user_response(connection); 2813 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2814 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2815 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2816 } 2817 } 2818 } 2819 return; 2820 } 2821 case SM_PH2_C1_W4_RANDOM_A: 2822 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2823 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2824 return; 2825 case SM_PH2_C1_W4_RANDOM_B: 2826 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2827 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2828 return; 2829 case SM_PH3_W4_RANDOM: 2830 reverse_64(data, setup->sm_local_rand); 2831 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2832 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2833 // no db for authenticated flag hack: store flag in bit 4 of LSB 2834 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2835 connection->sm_engine_state = SM_PH3_GET_DIV; 2836 return; 2837 case SM_PH3_W4_DIV: 2838 // use 16 bit from random value as div 2839 setup->sm_local_div = big_endian_read_16(data, 0); 2840 log_info_hex16("div", setup->sm_local_div); 2841 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2842 return; 2843 default: 2844 break; 2845 } 2846 } 2847 2848 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2849 2850 sm_connection_t * sm_conn; 2851 hci_con_handle_t con_handle; 2852 2853 switch (packet_type) { 2854 2855 case HCI_EVENT_PACKET: 2856 switch (hci_event_packet_get_type(packet)) { 2857 2858 case BTSTACK_EVENT_STATE: 2859 // bt stack activated, get started 2860 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2861 log_info("HCI Working!"); 2862 2863 // set local addr for le device db 2864 bd_addr_t local_bd_addr; 2865 gap_local_bd_addr(local_bd_addr); 2866 le_device_db_set_local_bd_addr(local_bd_addr); 2867 2868 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2869 rau_state = RAU_IDLE; 2870 #ifdef USE_MBEDTLS_FOR_ECDH 2871 if (!sm_have_ec_keypair){ 2872 setup->sm_passkey_bit = 0; 2873 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2874 } 2875 #endif 2876 sm_run(); 2877 } 2878 break; 2879 2880 case HCI_EVENT_LE_META: 2881 switch (packet[2]) { 2882 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2883 2884 log_info("sm: connected"); 2885 2886 if (packet[3]) return; // connection failed 2887 2888 con_handle = little_endian_read_16(packet, 4); 2889 sm_conn = sm_get_connection_for_handle(con_handle); 2890 if (!sm_conn) break; 2891 2892 sm_conn->sm_handle = con_handle; 2893 sm_conn->sm_role = packet[6]; 2894 sm_conn->sm_peer_addr_type = packet[7]; 2895 reverse_bd_addr(&packet[8], 2896 sm_conn->sm_peer_address); 2897 2898 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2899 2900 // reset security properties 2901 sm_conn->sm_connection_encrypted = 0; 2902 sm_conn->sm_connection_authenticated = 0; 2903 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2904 sm_conn->sm_le_db_index = -1; 2905 2906 // prepare CSRK lookup (does not involve setup) 2907 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2908 2909 // just connected -> everything else happens in sm_run() 2910 if (sm_conn->sm_role){ 2911 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2912 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2913 if (sm_slave_request_security) { 2914 // request security if requested by app 2915 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2916 } else { 2917 // otherwise, wait for pairing request 2918 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2919 } 2920 } 2921 break; 2922 } else { 2923 // master 2924 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2925 } 2926 break; 2927 2928 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2929 con_handle = little_endian_read_16(packet, 3); 2930 sm_conn = sm_get_connection_for_handle(con_handle); 2931 if (!sm_conn) break; 2932 2933 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2934 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2935 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2936 break; 2937 } 2938 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2939 // PH2 SEND LTK as we need to exchange keys in PH3 2940 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2941 break; 2942 } 2943 2944 // store rand and ediv 2945 reverse_64(&packet[5], sm_conn->sm_local_rand); 2946 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2947 2948 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2949 // potentially stored LTK is from the master 2950 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2951 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2952 break; 2953 } 2954 2955 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2956 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 2957 #else 2958 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2959 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2960 #endif 2961 break; 2962 2963 default: 2964 break; 2965 } 2966 break; 2967 2968 case HCI_EVENT_ENCRYPTION_CHANGE: 2969 con_handle = little_endian_read_16(packet, 3); 2970 sm_conn = sm_get_connection_for_handle(con_handle); 2971 if (!sm_conn) break; 2972 2973 sm_conn->sm_connection_encrypted = packet[5]; 2974 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2975 sm_conn->sm_actual_encryption_key_size); 2976 log_info("event handler, state %u", sm_conn->sm_engine_state); 2977 if (!sm_conn->sm_connection_encrypted) break; 2978 // continue if part of initial pairing 2979 switch (sm_conn->sm_engine_state){ 2980 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2981 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2982 sm_done_for_handle(sm_conn->sm_handle); 2983 break; 2984 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2985 if (sm_conn->sm_role){ 2986 // slave 2987 if (setup->sm_use_secure_connections){ 2988 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2989 } else { 2990 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2991 } 2992 } else { 2993 // master 2994 if (sm_key_distribution_all_received(sm_conn)){ 2995 // skip receiving keys as there are none 2996 sm_key_distribution_handle_all_received(sm_conn); 2997 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2998 } else { 2999 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3000 } 3001 } 3002 break; 3003 default: 3004 break; 3005 } 3006 break; 3007 3008 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3009 con_handle = little_endian_read_16(packet, 3); 3010 sm_conn = sm_get_connection_for_handle(con_handle); 3011 if (!sm_conn) break; 3012 3013 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3014 log_info("event handler, state %u", sm_conn->sm_engine_state); 3015 // continue if part of initial pairing 3016 switch (sm_conn->sm_engine_state){ 3017 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3018 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3019 sm_done_for_handle(sm_conn->sm_handle); 3020 break; 3021 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3022 if (sm_conn->sm_role){ 3023 // slave 3024 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3025 } else { 3026 // master 3027 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3028 } 3029 break; 3030 default: 3031 break; 3032 } 3033 break; 3034 3035 3036 case HCI_EVENT_DISCONNECTION_COMPLETE: 3037 con_handle = little_endian_read_16(packet, 3); 3038 sm_done_for_handle(con_handle); 3039 sm_conn = sm_get_connection_for_handle(con_handle); 3040 if (!sm_conn) break; 3041 3042 // delete stored bonding on disconnect with authentication failure in ph0 3043 if (sm_conn->sm_role == 0 3044 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3045 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3046 le_device_db_remove(sm_conn->sm_le_db_index); 3047 } 3048 3049 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3050 sm_conn->sm_handle = 0; 3051 break; 3052 3053 case HCI_EVENT_COMMAND_COMPLETE: 3054 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3055 sm_handle_encryption_result(&packet[6]); 3056 break; 3057 } 3058 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3059 sm_handle_random_result(&packet[6]); 3060 break; 3061 } 3062 break; 3063 default: 3064 break; 3065 } 3066 break; 3067 default: 3068 break; 3069 } 3070 3071 sm_run(); 3072 } 3073 3074 static inline int sm_calc_actual_encryption_key_size(int other){ 3075 if (other < sm_min_encryption_key_size) return 0; 3076 if (other < sm_max_encryption_key_size) return other; 3077 return sm_max_encryption_key_size; 3078 } 3079 3080 3081 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3082 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3083 switch (method){ 3084 case JUST_WORKS: 3085 case NK_BOTH_INPUT: 3086 return 1; 3087 default: 3088 return 0; 3089 } 3090 } 3091 // responder 3092 3093 static int sm_passkey_used(stk_generation_method_t method){ 3094 switch (method){ 3095 case PK_RESP_INPUT: 3096 return 1; 3097 default: 3098 return 0; 3099 } 3100 } 3101 #endif 3102 3103 /** 3104 * @return ok 3105 */ 3106 static int sm_validate_stk_generation_method(void){ 3107 // check if STK generation method is acceptable by client 3108 switch (setup->sm_stk_generation_method){ 3109 case JUST_WORKS: 3110 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3111 case PK_RESP_INPUT: 3112 case PK_INIT_INPUT: 3113 case OK_BOTH_INPUT: 3114 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3115 case OOB: 3116 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3117 case NK_BOTH_INPUT: 3118 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3119 return 1; 3120 default: 3121 return 0; 3122 } 3123 } 3124 3125 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3126 3127 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3128 sm_run(); 3129 } 3130 3131 if (packet_type != SM_DATA_PACKET) return; 3132 3133 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3134 if (!sm_conn) return; 3135 3136 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3137 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3138 return; 3139 } 3140 3141 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3142 3143 int err; 3144 3145 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3146 uint8_t buffer[5]; 3147 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3148 buffer[1] = 3; 3149 little_endian_store_16(buffer, 2, con_handle); 3150 buffer[4] = packet[1]; 3151 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3152 return; 3153 } 3154 3155 switch (sm_conn->sm_engine_state){ 3156 3157 // a sm timeout requries a new physical connection 3158 case SM_GENERAL_TIMEOUT: 3159 return; 3160 3161 // Initiator 3162 case SM_INITIATOR_CONNECTED: 3163 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3164 sm_pdu_received_in_wrong_state(sm_conn); 3165 break; 3166 } 3167 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3168 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3169 break; 3170 } 3171 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3172 sm_key_t ltk; 3173 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3174 if (!sm_is_null_key(ltk)){ 3175 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3176 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3177 } else { 3178 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3179 } 3180 break; 3181 } 3182 // otherwise, store security request 3183 sm_conn->sm_security_request_received = 1; 3184 break; 3185 3186 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3187 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3188 sm_pdu_received_in_wrong_state(sm_conn); 3189 break; 3190 } 3191 // store pairing request 3192 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3193 err = sm_stk_generation_init(sm_conn); 3194 if (err){ 3195 setup->sm_pairing_failed_reason = err; 3196 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3197 break; 3198 } 3199 3200 // generate random number first, if we need to show passkey 3201 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3202 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3203 break; 3204 } 3205 3206 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3207 if (setup->sm_use_secure_connections){ 3208 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3209 if (setup->sm_stk_generation_method == JUST_WORKS){ 3210 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3211 sm_trigger_user_response(sm_conn); 3212 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3213 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3214 } 3215 } else { 3216 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3217 } 3218 break; 3219 } 3220 #endif 3221 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3222 sm_trigger_user_response(sm_conn); 3223 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3224 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3225 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3226 } 3227 break; 3228 3229 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3230 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3231 sm_pdu_received_in_wrong_state(sm_conn); 3232 break; 3233 } 3234 3235 // store s_confirm 3236 reverse_128(&packet[1], setup->sm_peer_confirm); 3237 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3238 break; 3239 3240 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3241 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3242 sm_pdu_received_in_wrong_state(sm_conn); 3243 break;; 3244 } 3245 3246 // received random value 3247 reverse_128(&packet[1], setup->sm_peer_random); 3248 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3249 break; 3250 3251 // Responder 3252 case SM_RESPONDER_IDLE: 3253 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3254 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3255 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3256 sm_pdu_received_in_wrong_state(sm_conn); 3257 break;; 3258 } 3259 3260 // store pairing request 3261 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3262 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3263 break; 3264 3265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3266 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3267 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3268 sm_pdu_received_in_wrong_state(sm_conn); 3269 break; 3270 } 3271 3272 // store public key for DH Key calculation 3273 reverse_256(&packet[01], setup->sm_peer_qx); 3274 reverse_256(&packet[33], setup->sm_peer_qy); 3275 3276 #ifdef USE_MBEDTLS_FOR_ECDH 3277 // validate public key 3278 mbedtls_ecp_point Q; 3279 mbedtls_ecp_point_init( &Q ); 3280 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3281 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3282 mbedtls_mpi_lset(&Q.Z, 1); 3283 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3284 mbedtls_ecp_point_free( & Q); 3285 if (err){ 3286 log_error("sm: peer public key invalid %x", err); 3287 // uses "unspecified reason", there is no "public key invalid" error code 3288 sm_pdu_received_in_wrong_state(sm_conn); 3289 break; 3290 } 3291 3292 #endif 3293 if (sm_conn->sm_role){ 3294 // responder 3295 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3296 } else { 3297 // initiator 3298 // stk generation method 3299 // passkey entry: notify app to show passkey or to request passkey 3300 switch (setup->sm_stk_generation_method){ 3301 case JUST_WORKS: 3302 case NK_BOTH_INPUT: 3303 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3304 break; 3305 case PK_RESP_INPUT: 3306 sm_sc_start_calculating_local_confirm(sm_conn); 3307 break; 3308 case PK_INIT_INPUT: 3309 case OK_BOTH_INPUT: 3310 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3311 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3312 break; 3313 } 3314 sm_sc_start_calculating_local_confirm(sm_conn); 3315 break; 3316 case OOB: 3317 // TODO: implement SC OOB 3318 break; 3319 } 3320 } 3321 break; 3322 3323 case SM_SC_W4_CONFIRMATION: 3324 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3325 sm_pdu_received_in_wrong_state(sm_conn); 3326 break; 3327 } 3328 // received confirm value 3329 reverse_128(&packet[1], setup->sm_peer_confirm); 3330 3331 if (sm_conn->sm_role){ 3332 // responder 3333 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3334 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3335 // still waiting for passkey 3336 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3337 break; 3338 } 3339 } 3340 sm_sc_start_calculating_local_confirm(sm_conn); 3341 } else { 3342 // initiator 3343 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3344 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3345 } else { 3346 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3347 } 3348 } 3349 break; 3350 3351 case SM_SC_W4_PAIRING_RANDOM: 3352 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3353 sm_pdu_received_in_wrong_state(sm_conn); 3354 break; 3355 } 3356 3357 // received random value 3358 reverse_128(&packet[1], setup->sm_peer_nonce); 3359 3360 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3361 // only check for JUST WORK/NC in initiator role AND passkey entry 3362 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3363 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3364 } 3365 3366 sm_sc_state_after_receiving_random(sm_conn); 3367 break; 3368 3369 case SM_SC_W2_CALCULATE_G2: 3370 case SM_SC_W4_CALCULATE_G2: 3371 case SM_SC_W2_CALCULATE_F5_SALT: 3372 case SM_SC_W4_CALCULATE_F5_SALT: 3373 case SM_SC_W2_CALCULATE_F5_MACKEY: 3374 case SM_SC_W4_CALCULATE_F5_MACKEY: 3375 case SM_SC_W2_CALCULATE_F5_LTK: 3376 case SM_SC_W4_CALCULATE_F5_LTK: 3377 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3378 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3379 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3380 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3381 sm_pdu_received_in_wrong_state(sm_conn); 3382 break; 3383 } 3384 // store DHKey Check 3385 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3386 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3387 3388 // have we been only waiting for dhkey check command? 3389 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3390 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3391 } 3392 break; 3393 #endif 3394 3395 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3396 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3397 sm_pdu_received_in_wrong_state(sm_conn); 3398 break; 3399 } 3400 3401 // received confirm value 3402 reverse_128(&packet[1], setup->sm_peer_confirm); 3403 3404 // notify client to hide shown passkey 3405 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3406 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3407 } 3408 3409 // handle user cancel pairing? 3410 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3411 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3412 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3413 break; 3414 } 3415 3416 // wait for user action? 3417 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3418 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3419 break; 3420 } 3421 3422 // calculate and send local_confirm 3423 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3424 break; 3425 3426 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3427 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3428 sm_pdu_received_in_wrong_state(sm_conn); 3429 break;; 3430 } 3431 3432 // received random value 3433 reverse_128(&packet[1], setup->sm_peer_random); 3434 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3435 break; 3436 3437 case SM_PH3_RECEIVE_KEYS: 3438 switch(packet[0]){ 3439 case SM_CODE_ENCRYPTION_INFORMATION: 3440 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3441 reverse_128(&packet[1], setup->sm_peer_ltk); 3442 break; 3443 3444 case SM_CODE_MASTER_IDENTIFICATION: 3445 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3446 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3447 reverse_64(&packet[3], setup->sm_peer_rand); 3448 break; 3449 3450 case SM_CODE_IDENTITY_INFORMATION: 3451 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3452 reverse_128(&packet[1], setup->sm_peer_irk); 3453 break; 3454 3455 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3456 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3457 setup->sm_peer_addr_type = packet[1]; 3458 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3459 break; 3460 3461 case SM_CODE_SIGNING_INFORMATION: 3462 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3463 reverse_128(&packet[1], setup->sm_peer_csrk); 3464 break; 3465 default: 3466 // Unexpected PDU 3467 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3468 break; 3469 } 3470 // done with key distribution? 3471 if (sm_key_distribution_all_received(sm_conn)){ 3472 3473 sm_key_distribution_handle_all_received(sm_conn); 3474 3475 if (sm_conn->sm_role){ 3476 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3477 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3478 } else { 3479 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3480 sm_done_for_handle(sm_conn->sm_handle); 3481 } 3482 } else { 3483 if (setup->sm_use_secure_connections){ 3484 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3485 } else { 3486 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3487 } 3488 } 3489 } 3490 break; 3491 default: 3492 // Unexpected PDU 3493 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3494 break; 3495 } 3496 3497 // try to send preparared packet 3498 sm_run(); 3499 } 3500 3501 // Security Manager Client API 3502 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3503 sm_get_oob_data = get_oob_data_callback; 3504 } 3505 3506 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3507 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3508 } 3509 3510 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3511 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3512 } 3513 3514 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3515 sm_min_encryption_key_size = min_size; 3516 sm_max_encryption_key_size = max_size; 3517 } 3518 3519 void sm_set_authentication_requirements(uint8_t auth_req){ 3520 sm_auth_req = auth_req; 3521 } 3522 3523 void sm_set_io_capabilities(io_capability_t io_capability){ 3524 sm_io_capabilities = io_capability; 3525 } 3526 3527 void sm_set_request_security(int enable){ 3528 sm_slave_request_security = enable; 3529 } 3530 3531 void sm_set_er(sm_key_t er){ 3532 memcpy(sm_persistent_er, er, 16); 3533 } 3534 3535 void sm_set_ir(sm_key_t ir){ 3536 memcpy(sm_persistent_ir, ir, 16); 3537 } 3538 3539 // Testing support only 3540 void sm_test_set_irk(sm_key_t irk){ 3541 memcpy(sm_persistent_irk, irk, 16); 3542 sm_persistent_irk_ready = 1; 3543 } 3544 3545 void sm_test_use_fixed_local_csrk(void){ 3546 test_use_fixed_local_csrk = 1; 3547 } 3548 3549 void sm_init(void){ 3550 // set some (BTstack default) ER and IR 3551 int i; 3552 sm_key_t er; 3553 sm_key_t ir; 3554 for (i=0;i<16;i++){ 3555 er[i] = 0x30 + i; 3556 ir[i] = 0x90 + i; 3557 } 3558 sm_set_er(er); 3559 sm_set_ir(ir); 3560 // defaults 3561 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3562 | SM_STK_GENERATION_METHOD_OOB 3563 | SM_STK_GENERATION_METHOD_PASSKEY 3564 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3565 3566 sm_max_encryption_key_size = 16; 3567 sm_min_encryption_key_size = 7; 3568 3569 sm_cmac_state = CMAC_IDLE; 3570 dkg_state = DKG_W4_WORKING; 3571 rau_state = RAU_W4_WORKING; 3572 sm_aes128_state = SM_AES128_IDLE; 3573 sm_address_resolution_test = -1; // no private address to resolve yet 3574 sm_address_resolution_ah_calculation_active = 0; 3575 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3576 sm_address_resolution_general_queue = NULL; 3577 3578 gap_random_adress_update_period = 15 * 60 * 1000L; 3579 3580 sm_active_connection = 0; 3581 3582 test_use_fixed_local_csrk = 0; 3583 3584 // register for HCI Events from HCI 3585 hci_event_callback_registration.callback = &sm_event_packet_handler; 3586 hci_add_event_handler(&hci_event_callback_registration); 3587 3588 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3589 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3590 3591 #ifdef USE_MBEDTLS_FOR_ECDH 3592 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3593 3594 #ifndef HAVE_MALLOC 3595 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3596 #endif 3597 mbedtls_ecp_group_init(&mbedtls_ec_group); 3598 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3599 #if 0 3600 // test 3601 sm_test_use_fixed_ec_keypair(); 3602 if (sm_have_ec_keypair){ 3603 printf("test dhkey check\n"); 3604 sm_key256_t dhkey; 3605 memcpy(setup->sm_peer_qx, ec_qx, 32); 3606 memcpy(setup->sm_peer_qy, ec_qy, 32); 3607 sm_sc_calculate_dhkey(dhkey); 3608 } 3609 #endif 3610 #endif 3611 } 3612 3613 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3614 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3615 memcpy(ec_qx, qx, 32); 3616 memcpy(ec_qy, qy, 32); 3617 memcpy(ec_d, d, 32); 3618 sm_have_ec_keypair = 1; 3619 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3620 #endif 3621 } 3622 3623 void sm_test_use_fixed_ec_keypair(void){ 3624 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3625 #ifdef USE_MBEDTLS_FOR_ECDH 3626 // use test keypair from spec 3627 mbedtls_mpi x; 3628 mbedtls_mpi_init(&x); 3629 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3630 mbedtls_mpi_write_binary(&x, ec_d, 32); 3631 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3632 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3633 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3634 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3635 mbedtls_mpi_free(&x); 3636 #endif 3637 sm_have_ec_keypair = 1; 3638 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3639 #endif 3640 } 3641 3642 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3643 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3644 if (!hci_con) return NULL; 3645 return &hci_con->sm_connection; 3646 } 3647 3648 // @returns 0 if not encrypted, 7-16 otherwise 3649 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3650 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3651 if (!sm_conn) return 0; // wrong connection 3652 if (!sm_conn->sm_connection_encrypted) return 0; 3653 return sm_conn->sm_actual_encryption_key_size; 3654 } 3655 3656 int sm_authenticated(hci_con_handle_t con_handle){ 3657 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3658 if (!sm_conn) return 0; // wrong connection 3659 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3660 return sm_conn->sm_connection_authenticated; 3661 } 3662 3663 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3664 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3665 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3666 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3667 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3668 return sm_conn->sm_connection_authorization_state; 3669 } 3670 3671 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3672 switch (sm_conn->sm_engine_state){ 3673 case SM_GENERAL_IDLE: 3674 case SM_RESPONDER_IDLE: 3675 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3676 sm_run(); 3677 break; 3678 default: 3679 break; 3680 } 3681 } 3682 3683 /** 3684 * @brief Trigger Security Request 3685 */ 3686 void sm_send_security_request(hci_con_handle_t con_handle){ 3687 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3688 if (!sm_conn) return; 3689 sm_send_security_request_for_connection(sm_conn); 3690 } 3691 3692 // request pairing 3693 void sm_request_pairing(hci_con_handle_t con_handle){ 3694 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3695 if (!sm_conn) return; // wrong connection 3696 3697 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3698 if (sm_conn->sm_role){ 3699 sm_send_security_request_for_connection(sm_conn); 3700 } else { 3701 // used as a trigger to start central/master/initiator security procedures 3702 uint16_t ediv; 3703 sm_key_t ltk; 3704 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3705 switch (sm_conn->sm_irk_lookup_state){ 3706 case IRK_LOOKUP_FAILED: 3707 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3708 break; 3709 case IRK_LOOKUP_SUCCEEDED: 3710 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3711 if (!sm_is_null_key(ltk) || ediv){ 3712 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3713 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3714 } else { 3715 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3716 } 3717 break; 3718 default: 3719 sm_conn->sm_bonding_requested = 1; 3720 break; 3721 } 3722 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3723 sm_conn->sm_bonding_requested = 1; 3724 } 3725 } 3726 sm_run(); 3727 } 3728 3729 // called by client app on authorization request 3730 void sm_authorization_decline(hci_con_handle_t con_handle){ 3731 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3732 if (!sm_conn) return; // wrong connection 3733 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3734 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3735 } 3736 3737 void sm_authorization_grant(hci_con_handle_t con_handle){ 3738 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3739 if (!sm_conn) return; // wrong connection 3740 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3741 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3742 } 3743 3744 // GAP Bonding API 3745 3746 void sm_bonding_decline(hci_con_handle_t con_handle){ 3747 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3748 if (!sm_conn) return; // wrong connection 3749 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3750 3751 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3752 switch (setup->sm_stk_generation_method){ 3753 case PK_RESP_INPUT: 3754 case PK_INIT_INPUT: 3755 case OK_BOTH_INPUT: 3756 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3757 break; 3758 case NK_BOTH_INPUT: 3759 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3760 break; 3761 case JUST_WORKS: 3762 case OOB: 3763 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3764 break; 3765 } 3766 } 3767 sm_run(); 3768 } 3769 3770 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3771 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3772 if (!sm_conn) return; // wrong connection 3773 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3774 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3775 if (setup->sm_use_secure_connections){ 3776 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3777 } else { 3778 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3779 } 3780 } 3781 3782 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3783 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3784 sm_sc_prepare_dhkey_check(sm_conn); 3785 } 3786 #endif 3787 3788 sm_run(); 3789 } 3790 3791 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3792 // for now, it's the same 3793 sm_just_works_confirm(con_handle); 3794 } 3795 3796 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3797 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3798 if (!sm_conn) return; // wrong connection 3799 sm_reset_tk(); 3800 big_endian_store_32(setup->sm_tk, 12, passkey); 3801 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3802 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3803 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3804 } 3805 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3806 memcpy(setup->sm_ra, setup->sm_tk, 16); 3807 memcpy(setup->sm_rb, setup->sm_tk, 16); 3808 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3809 sm_sc_start_calculating_local_confirm(sm_conn); 3810 } 3811 #endif 3812 sm_run(); 3813 } 3814 3815 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3816 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3817 if (!sm_conn) return; // wrong connection 3818 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3819 setup->sm_keypress_notification = action; 3820 sm_run(); 3821 } 3822 3823 /** 3824 * @brief Identify device in LE Device DB 3825 * @param handle 3826 * @returns index from le_device_db or -1 if not found/identified 3827 */ 3828 int sm_le_device_index(hci_con_handle_t con_handle ){ 3829 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3830 if (!sm_conn) return -1; 3831 return sm_conn->sm_le_db_index; 3832 } 3833 3834 // GAP LE API 3835 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3836 gap_random_address_update_stop(); 3837 gap_random_adress_type = random_address_type; 3838 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3839 gap_random_address_update_start(); 3840 gap_random_address_trigger(); 3841 } 3842 3843 gap_random_address_type_t gap_random_address_get_mode(void){ 3844 return gap_random_adress_type; 3845 } 3846 3847 void gap_random_address_set_update_period(int period_ms){ 3848 gap_random_adress_update_period = period_ms; 3849 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3850 gap_random_address_update_stop(); 3851 gap_random_address_update_start(); 3852 } 3853 3854 void gap_random_address_set(bd_addr_t addr){ 3855 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3856 memcpy(sm_random_address, addr, 6); 3857 rau_state = RAU_SET_ADDRESS; 3858 sm_run(); 3859 } 3860 3861 /* 3862 * @brief Set Advertisement Paramters 3863 * @param adv_int_min 3864 * @param adv_int_max 3865 * @param adv_type 3866 * @param direct_address_type 3867 * @param direct_address 3868 * @param channel_map 3869 * @param filter_policy 3870 * 3871 * @note own_address_type is used from gap_random_address_set_mode 3872 */ 3873 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3874 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3875 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3876 direct_address_typ, direct_address, channel_map, filter_policy); 3877 } 3878 3879