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 // TODO: remove software AES 55 #include "rijndael.h" 56 #endif 57 58 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(HAVE_HCI_CONTROLLER_DHKEY_SUPPORT) 59 #define USE_MBEDTLS_FOR_ECDH 60 #endif 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #if !defined(MBEDTLS_CONFIG_FILE) 65 #include "mbedtls/config.h" 66 #else 67 #include MBEDTLS_CONFIG_FILE 68 #endif 69 #if defined(MBEDTLS_PLATFORM_C) 70 #include "mbedtls/platform.h" 71 #else 72 #include <stdio.h> 73 #define mbedtls_printf printf 74 #endif 75 #include "mbedtls/ecp.h" 76 #endif 77 78 // 79 // SM internal types and globals 80 // 81 82 typedef enum { 83 DKG_W4_WORKING, 84 DKG_CALC_IRK, 85 DKG_W4_IRK, 86 DKG_CALC_DHK, 87 DKG_W4_DHK, 88 DKG_READY 89 } derived_key_generation_t; 90 91 typedef enum { 92 RAU_W4_WORKING, 93 RAU_IDLE, 94 RAU_GET_RANDOM, 95 RAU_W4_RANDOM, 96 RAU_GET_ENC, 97 RAU_W4_ENC, 98 RAU_SET_ADDRESS, 99 } random_address_update_t; 100 101 typedef enum { 102 CMAC_IDLE, 103 CMAC_CALC_SUBKEYS, 104 CMAC_W4_SUBKEYS, 105 CMAC_CALC_MI, 106 CMAC_W4_MI, 107 CMAC_CALC_MLAST, 108 CMAC_W4_MLAST 109 } cmac_state_t; 110 111 typedef enum { 112 JUST_WORKS, 113 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 114 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 115 OK_BOTH_INPUT, // Only input on both, both input PK 116 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 117 OOB // OOB available on both sides 118 } stk_generation_method_t; 119 120 typedef enum { 121 SM_USER_RESPONSE_IDLE, 122 SM_USER_RESPONSE_PENDING, 123 SM_USER_RESPONSE_CONFIRM, 124 SM_USER_RESPONSE_PASSKEY, 125 SM_USER_RESPONSE_DECLINE 126 } sm_user_response_t; 127 128 typedef enum { 129 SM_AES128_IDLE, 130 SM_AES128_ACTIVE 131 } sm_aes128_state_t; 132 133 typedef enum { 134 ADDRESS_RESOLUTION_IDLE, 135 ADDRESS_RESOLUTION_GENERAL, 136 ADDRESS_RESOLUTION_FOR_CONNECTION, 137 } address_resolution_mode_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_SUCEEDED, 141 ADDRESS_RESOLUTION_FAILED, 142 } address_resolution_event_t; 143 // 144 // GLOBAL DATA 145 // 146 147 static uint8_t test_use_fixed_local_csrk; 148 149 // configuration 150 static uint8_t sm_accepted_stk_generation_methods; 151 static uint8_t sm_max_encryption_key_size; 152 static uint8_t sm_min_encryption_key_size; 153 static uint8_t sm_auth_req = 0; 154 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 155 static uint8_t sm_slave_request_security; 156 157 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 158 static sm_key_t sm_persistent_er; 159 static sm_key_t sm_persistent_ir; 160 161 // derived from sm_persistent_ir 162 static sm_key_t sm_persistent_dhk; 163 static sm_key_t sm_persistent_irk; 164 static uint8_t sm_persistent_irk_ready = 0; // used for testing 165 static derived_key_generation_t dkg_state; 166 167 // derived from sm_persistent_er 168 // .. 169 170 // random address update 171 static random_address_update_t rau_state; 172 static bd_addr_t sm_random_address; 173 174 // CMAC Calculation: General 175 static cmac_state_t sm_cmac_state; 176 static uint16_t sm_cmac_message_len; 177 static sm_key_t sm_cmac_k; 178 static sm_key_t sm_cmac_x; 179 static sm_key_t sm_cmac_m_last; 180 static uint8_t sm_cmac_block_current; 181 static uint8_t sm_cmac_block_count; 182 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 183 static void (*sm_cmac_done_handler)(uint8_t * hash); 184 185 // CMAC for ATT Signed Writes 186 static uint8_t sm_cmac_header[3]; 187 static const uint8_t * sm_cmac_message; 188 static uint8_t sm_cmac_sign_counter[4]; 189 190 // CMAC for Secure Connection functions 191 #ifdef ENABLE_LE_SECURE_CONNECTIONS 192 static sm_connection_t * sm_cmac_connection; 193 static uint8_t sm_cmac_sc_buffer[80]; 194 #endif 195 196 // resolvable private address lookup / CSRK calculation 197 static int sm_address_resolution_test; 198 static int sm_address_resolution_ah_calculation_active; 199 static uint8_t sm_address_resolution_addr_type; 200 static bd_addr_t sm_address_resolution_address; 201 static void * sm_address_resolution_context; 202 static address_resolution_mode_t sm_address_resolution_mode; 203 static btstack_linked_list_t sm_address_resolution_general_queue; 204 205 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 206 static sm_aes128_state_t sm_aes128_state; 207 static void * sm_aes128_context; 208 209 // random engine. store context (ususally sm_connection_t) 210 static void * sm_random_context; 211 212 // to receive hci events 213 static btstack_packet_callback_registration_t hci_event_callback_registration; 214 215 /* to dispatch sm event */ 216 static btstack_linked_list_t sm_event_handlers; 217 218 // Software ECDH implementation provided by mbedtls 219 #ifdef USE_MBEDTLS_FOR_ECDH 220 mbedtls_ecp_keypair le_keypair; 221 #endif 222 223 // 224 // Volume 3, Part H, Chapter 24 225 // "Security shall be initiated by the Security Manager in the device in the master role. 226 // The device in the slave role shall be the responding device." 227 // -> master := initiator, slave := responder 228 // 229 230 // data needed for security setup 231 typedef struct sm_setup_context { 232 233 btstack_timer_source_t sm_timeout; 234 235 // used in all phases 236 uint8_t sm_pairing_failed_reason; 237 238 // user response, (Phase 1 and/or 2) 239 uint8_t sm_user_response; 240 241 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 242 int sm_key_distribution_send_set; 243 int sm_key_distribution_received_set; 244 245 // Phase 2 (Pairing over SMP) 246 stk_generation_method_t sm_stk_generation_method; 247 sm_key_t sm_tk; 248 uint8_t sm_use_secure_connections; 249 250 sm_key_t sm_c1_t3_value; // c1 calculation 251 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 252 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 253 sm_key_t sm_local_random; 254 sm_key_t sm_local_confirm; 255 sm_key_t sm_peer_random; 256 sm_key_t sm_peer_confirm; 257 uint8_t sm_m_addr_type; // address and type can be removed 258 uint8_t sm_s_addr_type; // '' 259 bd_addr_t sm_m_address; // '' 260 bd_addr_t sm_s_address; // '' 261 sm_key_t sm_ltk; 262 263 #ifdef ENABLE_LE_SECURE_CONNECTIONS 264 uint8_t sm_peer_qx[32]; 265 uint8_t sm_peer_qy[32]; 266 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 267 sm_key_t sm_local_nonce; // might be combined with sm_local_random 268 sm_key_t sm_peer_dhkey_check; 269 sm_key_t sm_local_dhkey_check; 270 sm_key_t sm_ra; 271 sm_key_t sm_rb; 272 sm_key_t sm_t; // used for f5 273 sm_key_t sm_mackey; 274 uint8_t sm_passkey_bit; 275 #endif 276 277 // Phase 3 278 279 // key distribution, we generate 280 uint16_t sm_local_y; 281 uint16_t sm_local_div; 282 uint16_t sm_local_ediv; 283 uint8_t sm_local_rand[8]; 284 sm_key_t sm_local_ltk; 285 sm_key_t sm_local_csrk; 286 sm_key_t sm_local_irk; 287 // sm_local_address/addr_type not needed 288 289 // key distribution, received from peer 290 uint16_t sm_peer_y; 291 uint16_t sm_peer_div; 292 uint16_t sm_peer_ediv; 293 uint8_t sm_peer_rand[8]; 294 sm_key_t sm_peer_ltk; 295 sm_key_t sm_peer_irk; 296 sm_key_t sm_peer_csrk; 297 uint8_t sm_peer_addr_type; 298 bd_addr_t sm_peer_address; 299 300 } sm_setup_context_t; 301 302 // 303 static sm_setup_context_t the_setup; 304 static sm_setup_context_t * setup = &the_setup; 305 306 // active connection - the one for which the_setup is used for 307 static uint16_t sm_active_connection = 0; 308 309 // @returns 1 if oob data is available 310 // stores oob data in provided 16 byte buffer if not null 311 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 312 313 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 314 static btstack_packet_handler_t sm_client_packet_handler = NULL; 315 316 // horizontal: initiator capabilities 317 // vertial: responder capabilities 318 static const stk_generation_method_t stk_generation_method [5] [5] = { 319 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 320 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 321 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 322 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 323 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 324 }; 325 326 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 327 #ifdef ENABLE_LE_SECURE_CONNECTIONS 328 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 329 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 330 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 331 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 332 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 333 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 334 }; 335 #endif 336 337 static void sm_run(void); 338 static void sm_done_for_handle(hci_con_handle_t con_handle); 339 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 340 static inline int sm_calc_actual_encryption_key_size(int other); 341 static int sm_validate_stk_generation_method(void); 342 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 343 344 static void log_info_hex16(const char * name, uint16_t value){ 345 log_info("%-6s 0x%04x", name, value); 346 } 347 348 // @returns 1 if all bytes are 0 349 static int sm_is_null_random(uint8_t random[8]){ 350 int i; 351 for (i=0; i < 8 ; i++){ 352 if (random[i]) return 0; 353 } 354 return 1; 355 } 356 357 // Key utils 358 static void sm_reset_tk(void){ 359 int i; 360 for (i=0;i<16;i++){ 361 setup->sm_tk[i] = 0; 362 } 363 } 364 365 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 366 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 367 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 368 int i; 369 for (i = max_encryption_size ; i < 16 ; i++){ 370 key[15-i] = 0; 371 } 372 } 373 374 // SMP Timeout implementation 375 376 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 377 // the Security Manager Timer shall be reset and started. 378 // 379 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 380 // 381 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 382 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 383 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 384 // established. 385 386 static void sm_timeout_handler(btstack_timer_source_t * timer){ 387 log_info("SM timeout"); 388 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 389 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 390 sm_done_for_handle(sm_conn->sm_handle); 391 392 // trigger handling of next ready connection 393 sm_run(); 394 } 395 static void sm_timeout_start(sm_connection_t * sm_conn){ 396 btstack_run_loop_remove_timer(&setup->sm_timeout); 397 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 398 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 399 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 400 btstack_run_loop_add_timer(&setup->sm_timeout); 401 } 402 static void sm_timeout_stop(void){ 403 btstack_run_loop_remove_timer(&setup->sm_timeout); 404 } 405 static void sm_timeout_reset(sm_connection_t * sm_conn){ 406 sm_timeout_stop(); 407 sm_timeout_start(sm_conn); 408 } 409 410 // end of sm timeout 411 412 // GAP Random Address updates 413 static gap_random_address_type_t gap_random_adress_type; 414 static btstack_timer_source_t gap_random_address_update_timer; 415 static uint32_t gap_random_adress_update_period; 416 417 static void gap_random_address_trigger(void){ 418 if (rau_state != RAU_IDLE) return; 419 log_info("gap_random_address_trigger"); 420 rau_state = RAU_GET_RANDOM; 421 sm_run(); 422 } 423 424 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 425 log_info("GAP Random Address Update due"); 426 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 427 btstack_run_loop_add_timer(&gap_random_address_update_timer); 428 gap_random_address_trigger(); 429 } 430 431 static void gap_random_address_update_start(void){ 432 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 433 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 434 btstack_run_loop_add_timer(&gap_random_address_update_timer); 435 } 436 437 static void gap_random_address_update_stop(void){ 438 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 439 } 440 441 442 static void sm_random_start(void * context){ 443 sm_random_context = context; 444 hci_send_cmd(&hci_le_rand); 445 } 446 447 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 448 // context is made availabe to aes128 result handler by this 449 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 450 sm_aes128_state = SM_AES128_ACTIVE; 451 sm_key_t key_flipped, plaintext_flipped; 452 reverse_128(key, key_flipped); 453 reverse_128(plaintext, plaintext_flipped); 454 sm_aes128_context = context; 455 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 456 } 457 458 // ah(k,r) helper 459 // r = padding || r 460 // r - 24 bit value 461 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 462 // r'= padding || r 463 memset(r_prime, 0, 16); 464 memcpy(&r_prime[13], r, 3); 465 } 466 467 // d1 helper 468 // d' = padding || r || d 469 // d,r - 16 bit values 470 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 471 // d'= padding || r || d 472 memset(d1_prime, 0, 16); 473 big_endian_store_16(d1_prime, 12, r); 474 big_endian_store_16(d1_prime, 14, d); 475 } 476 477 // dm helper 478 // r’ = padding || r 479 // r - 64 bit value 480 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 481 memset(r_prime, 0, 16); 482 memcpy(&r_prime[8], r, 8); 483 } 484 485 // calculate arguments for first AES128 operation in C1 function 486 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){ 487 488 // p1 = pres || preq || rat’ || iat’ 489 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 490 // cant octet of pres becomes the most significant octet of p1. 491 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 492 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 493 // p1 is 0x05000800000302070710000001010001." 494 495 sm_key_t p1; 496 reverse_56(pres, &p1[0]); 497 reverse_56(preq, &p1[7]); 498 p1[14] = rat; 499 p1[15] = iat; 500 log_info_key("p1", p1); 501 log_info_key("r", r); 502 503 // t1 = r xor p1 504 int i; 505 for (i=0;i<16;i++){ 506 t1[i] = r[i] ^ p1[i]; 507 } 508 log_info_key("t1", t1); 509 } 510 511 // calculate arguments for second AES128 operation in C1 function 512 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 513 // p2 = padding || ia || ra 514 // "The least significant octet of ra becomes the least significant octet of p2 and 515 // the most significant octet of padding becomes the most significant octet of p2. 516 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 517 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 518 519 sm_key_t p2; 520 memset(p2, 0, 16); 521 memcpy(&p2[4], ia, 6); 522 memcpy(&p2[10], ra, 6); 523 log_info_key("p2", p2); 524 525 // c1 = e(k, t2_xor_p2) 526 int i; 527 for (i=0;i<16;i++){ 528 t3[i] = t2[i] ^ p2[i]; 529 } 530 log_info_key("t3", t3); 531 } 532 533 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 534 log_info_key("r1", r1); 535 log_info_key("r2", r2); 536 memcpy(&r_prime[8], &r2[8], 8); 537 memcpy(&r_prime[0], &r1[8], 8); 538 } 539 540 #ifdef ENABLE_LE_SECURE_CONNECTIONS 541 // Software implementations of crypto toolbox for LE Secure Connection 542 // TODO: replace with code to use AES Engine of HCI Controller 543 typedef uint8_t sm_key24_t[3]; 544 typedef uint8_t sm_key56_t[7]; 545 typedef uint8_t sm_key256_t[32]; 546 547 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 548 uint32_t rk[RKLENGTH(KEYBITS)]; 549 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 550 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 551 } 552 553 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 554 memcpy(k1, k0, 16); 555 sm_shift_left_by_one_bit_inplace(16, k1); 556 if (k0[0] & 0x80){ 557 k1[15] ^= 0x87; 558 } 559 memcpy(k2, k1, 16); 560 sm_shift_left_by_one_bit_inplace(16, k2); 561 if (k1[0] & 0x80){ 562 k2[15] ^= 0x87; 563 } 564 } 565 566 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 567 sm_key_t k0, k1, k2, zero; 568 memset(zero, 0, 16); 569 570 aes128_calc_cyphertext(key, zero, k0); 571 calc_subkeys(k0, k1, k2); 572 573 int cmac_block_count = (cmac_message_len + 15) / 16; 574 575 // step 3: .. 576 if (cmac_block_count==0){ 577 cmac_block_count = 1; 578 } 579 580 // step 4: set m_last 581 sm_key_t cmac_m_last; 582 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 583 int i; 584 if (sm_cmac_last_block_complete){ 585 for (i=0;i<16;i++){ 586 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 587 } 588 } else { 589 int valid_octets_in_last_block = cmac_message_len & 0x0f; 590 for (i=0;i<16;i++){ 591 if (i < valid_octets_in_last_block){ 592 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 593 continue; 594 } 595 if (i == valid_octets_in_last_block){ 596 cmac_m_last[i] = 0x80 ^ k2[i]; 597 continue; 598 } 599 cmac_m_last[i] = k2[i]; 600 } 601 } 602 603 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 604 // LOG_KEY(cmac_m_last); 605 606 // Step 5 607 sm_key_t cmac_x; 608 memset(cmac_x, 0, 16); 609 610 // Step 6 611 sm_key_t sm_cmac_y; 612 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 613 for (i=0;i<16;i++){ 614 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 615 } 616 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 617 } 618 for (i=0;i<16;i++){ 619 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 620 } 621 622 // Step 7 623 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 624 } 625 626 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 627 // - U is 256 bits 628 // - V is 256 bits 629 // - X is 128 bits 630 // - Y is 128 bits 631 static uint32_t g2(const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 632 uint8_t buffer[80]; 633 memcpy(buffer, u, 32); 634 memcpy(buffer+32, v, 32); 635 memcpy(buffer+64, y, 16); 636 sm_key_t cmac; 637 log_info("g2 key"); 638 log_info_hexdump(x, 16); 639 log_info("g2 message"); 640 log_info_hexdump(buffer, sizeof(buffer)); 641 aes_cmac(cmac, x, buffer, sizeof(buffer)); 642 log_info("g2 result"); 643 log_info_hexdump(x, 16); 644 return big_endian_read_32(cmac, 12); 645 } 646 647 #if 0 648 // h6(W, keyID) = AES-CMACW(keyID) 649 // - W is 128 bits 650 // - keyID is 32 bits 651 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 652 uint8_t key_id_buffer[4]; 653 big_endian_store_32(key_id_buffer, 0, key_id); 654 aes_cmac(res, w, key_id_buffer, 4); 655 } 656 #endif 657 #endif 658 659 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){ 660 event[0] = type; 661 event[1] = event_size - 2; 662 little_endian_store_16(event, 2, con_handle); 663 event[4] = addr_type; 664 reverse_bd_addr(address, &event[5]); 665 } 666 667 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 668 if (sm_client_packet_handler) { 669 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 670 } 671 // dispatch to all event handlers 672 btstack_linked_list_iterator_t it; 673 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 674 while (btstack_linked_list_iterator_has_next(&it)){ 675 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 676 entry->callback(packet_type, 0, packet, size); 677 } 678 } 679 680 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 681 uint8_t event[11]; 682 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 683 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 684 } 685 686 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){ 687 uint8_t event[15]; 688 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 689 little_endian_store_32(event, 11, passkey); 690 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 691 } 692 693 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){ 694 uint8_t event[13]; 695 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 696 little_endian_store_16(event, 11, index); 697 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 698 } 699 700 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){ 701 702 uint8_t event[18]; 703 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 704 event[11] = result; 705 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 706 } 707 708 // decide on stk generation based on 709 // - pairing request 710 // - io capabilities 711 // - OOB data availability 712 static void sm_setup_tk(void){ 713 714 // default: just works 715 setup->sm_stk_generation_method = JUST_WORKS; 716 717 #ifdef ENABLE_LE_SECURE_CONNECTIONS 718 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 719 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 720 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 721 memset(setup->sm_ra, 0, 16); 722 memset(setup->sm_rb, 0, 16); 723 #else 724 setup->sm_use_secure_connections = 0; 725 #endif 726 727 // If both devices have not set the MITM option in the Authentication Requirements 728 // Flags, then the IO capabilities shall be ignored and the Just Works association 729 // model shall be used. 730 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 731 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 732 log_info("SM: MITM not required by both -> JUST WORKS"); 733 return; 734 } 735 736 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 737 738 // If both devices have out of band authentication data, then the Authentication 739 // Requirements Flags shall be ignored when selecting the pairing method and the 740 // Out of Band pairing method shall be used. 741 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 742 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 743 log_info("SM: have OOB data"); 744 log_info_key("OOB", setup->sm_tk); 745 setup->sm_stk_generation_method = OOB; 746 return; 747 } 748 749 // Reset TK as it has been setup in sm_init_setup 750 sm_reset_tk(); 751 752 // Also use just works if unknown io capabilites 753 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)){ 754 return; 755 } 756 757 // Otherwise the IO capabilities of the devices shall be used to determine the 758 // pairing method as defined in Table 2.4. 759 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 760 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 761 762 #ifdef ENABLE_LE_SECURE_CONNECTIONS 763 // table not define by default 764 if (setup->sm_use_secure_connections){ 765 generation_method = stk_generation_method_with_secure_connection; 766 } 767 #endif 768 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)]; 769 770 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 771 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); 772 } 773 774 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 775 int flags = 0; 776 if (key_set & SM_KEYDIST_ENC_KEY){ 777 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 778 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 779 } 780 if (key_set & SM_KEYDIST_ID_KEY){ 781 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 782 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 783 } 784 if (key_set & SM_KEYDIST_SIGN){ 785 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 786 } 787 return flags; 788 } 789 790 static void sm_setup_key_distribution(uint8_t key_set){ 791 setup->sm_key_distribution_received_set = 0; 792 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 793 } 794 795 // CSRK Key Lookup 796 797 798 static int sm_address_resolution_idle(void){ 799 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 800 } 801 802 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){ 803 memcpy(sm_address_resolution_address, addr, 6); 804 sm_address_resolution_addr_type = addr_type; 805 sm_address_resolution_test = 0; 806 sm_address_resolution_mode = mode; 807 sm_address_resolution_context = context; 808 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 809 } 810 811 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 812 // check if already in list 813 btstack_linked_list_iterator_t it; 814 sm_lookup_entry_t * entry; 815 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 816 while(btstack_linked_list_iterator_has_next(&it)){ 817 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 818 if (entry->address_type != address_type) continue; 819 if (memcmp(entry->address, address, 6)) continue; 820 // already in list 821 return BTSTACK_BUSY; 822 } 823 entry = btstack_memory_sm_lookup_entry_get(); 824 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 825 entry->address_type = (bd_addr_type_t) address_type; 826 memcpy(entry->address, address, 6); 827 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 828 sm_run(); 829 return 0; 830 } 831 832 // CMAC Implementation using AES128 engine 833 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 834 int i; 835 int carry = 0; 836 for (i=len-1; i >= 0 ; i--){ 837 int new_carry = data[i] >> 7; 838 data[i] = data[i] << 1 | carry; 839 carry = new_carry; 840 } 841 } 842 843 // 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 844 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 845 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 846 } 847 static inline void dkg_next_state(void){ 848 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 849 } 850 static inline void rau_next_state(void){ 851 rau_state = (random_address_update_t) (((int)rau_state) + 1); 852 } 853 854 // CMAC calculation using AES Engine 855 856 static inline void sm_cmac_next_state(void){ 857 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 858 } 859 860 static int sm_cmac_last_block_complete(void){ 861 if (sm_cmac_message_len == 0) return 0; 862 return (sm_cmac_message_len & 0x0f) == 0; 863 } 864 865 static inline uint8_t sm_cmac_message_get_byte(uint16_t offset){ 866 if (offset >= sm_cmac_message_len) { 867 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 868 return 0; 869 } 870 871 offset = sm_cmac_message_len - 1 - offset; 872 873 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 874 if (offset < 3){ 875 return sm_cmac_header[offset]; 876 } 877 int actual_message_len_incl_header = sm_cmac_message_len - 4; 878 if (offset < actual_message_len_incl_header){ 879 return sm_cmac_message[offset - 3]; 880 } 881 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 882 } 883 884 // generic cmac calculation 885 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])){ 886 // Generalized CMAC 887 memcpy(sm_cmac_k, key, 16); 888 memset(sm_cmac_x, 0, 16); 889 sm_cmac_block_current = 0; 890 sm_cmac_message_len = message_len; 891 sm_cmac_done_handler = done_callback; 892 sm_cmac_get_byte = get_byte_callback; 893 894 // step 2: n := ceil(len/const_Bsize); 895 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 896 897 // step 3: .. 898 if (sm_cmac_block_count==0){ 899 sm_cmac_block_count = 1; 900 } 901 902 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 903 904 // first, we need to compute l for k1, k2, and m_last 905 sm_cmac_state = CMAC_CALC_SUBKEYS; 906 907 // let's go 908 sm_run(); 909 } 910 911 // cmac for ATT Message signing 912 void sm_cmac_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)){ 913 // ATT Message Signing 914 sm_cmac_header[0] = opcode; 915 little_endian_store_16(sm_cmac_header, 1, con_handle); 916 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 917 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 918 sm_cmac_message = message; 919 sm_cmac_general_start(k, total_message_len, &sm_cmac_message_get_byte, done_handler); 920 } 921 922 int sm_cmac_ready(void){ 923 return sm_cmac_state == CMAC_IDLE; 924 } 925 926 static void sm_cmac_handle_aes_engine_ready(void){ 927 switch (sm_cmac_state){ 928 case CMAC_CALC_SUBKEYS: { 929 sm_key_t const_zero; 930 memset(const_zero, 0, 16); 931 sm_cmac_next_state(); 932 sm_aes128_start(sm_cmac_k, const_zero, NULL); 933 break; 934 } 935 case CMAC_CALC_MI: { 936 int j; 937 sm_key_t y; 938 for (j=0;j<16;j++){ 939 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 940 } 941 sm_cmac_block_current++; 942 sm_cmac_next_state(); 943 sm_aes128_start(sm_cmac_k, y, NULL); 944 break; 945 } 946 case CMAC_CALC_MLAST: { 947 int i; 948 sm_key_t y; 949 for (i=0;i<16;i++){ 950 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 951 } 952 log_info_key("Y", y); 953 sm_cmac_block_current++; 954 sm_cmac_next_state(); 955 sm_aes128_start(sm_cmac_k, y, NULL); 956 break; 957 } 958 default: 959 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 960 break; 961 } 962 } 963 964 static void sm_cmac_handle_encryption_result(sm_key_t data){ 965 switch (sm_cmac_state){ 966 case CMAC_W4_SUBKEYS: { 967 sm_key_t k1; 968 memcpy(k1, data, 16); 969 sm_shift_left_by_one_bit_inplace(16, k1); 970 if (data[0] & 0x80){ 971 k1[15] ^= 0x87; 972 } 973 sm_key_t k2; 974 memcpy(k2, k1, 16); 975 sm_shift_left_by_one_bit_inplace(16, k2); 976 if (k1[0] & 0x80){ 977 k2[15] ^= 0x87; 978 } 979 980 log_info_key("k", sm_cmac_k); 981 log_info_key("k1", k1); 982 log_info_key("k2", k2); 983 984 // step 4: set m_last 985 int i; 986 if (sm_cmac_last_block_complete()){ 987 for (i=0;i<16;i++){ 988 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 989 } 990 } else { 991 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 992 for (i=0;i<16;i++){ 993 if (i < valid_octets_in_last_block){ 994 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 995 continue; 996 } 997 if (i == valid_octets_in_last_block){ 998 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 999 continue; 1000 } 1001 sm_cmac_m_last[i] = k2[i]; 1002 } 1003 } 1004 1005 // next 1006 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1007 break; 1008 } 1009 case CMAC_W4_MI: 1010 memcpy(sm_cmac_x, data, 16); 1011 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1012 break; 1013 case CMAC_W4_MLAST: 1014 // done 1015 log_info("Setting CMAC Engine to IDLE"); 1016 sm_cmac_state = CMAC_IDLE; 1017 log_info_key("CMAC", data); 1018 sm_cmac_done_handler(data); 1019 break; 1020 default: 1021 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1022 break; 1023 } 1024 } 1025 1026 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1027 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1028 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1029 switch (setup->sm_stk_generation_method){ 1030 case PK_RESP_INPUT: 1031 if (sm_conn->sm_role){ 1032 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1033 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1034 } else { 1035 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)); 1036 } 1037 break; 1038 case PK_INIT_INPUT: 1039 if (sm_conn->sm_role){ 1040 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)); 1041 } else { 1042 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1043 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1044 } 1045 break; 1046 case OK_BOTH_INPUT: 1047 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1048 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1049 break; 1050 case NK_BOTH_INPUT: 1051 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1052 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)); 1053 break; 1054 case JUST_WORKS: 1055 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1056 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1057 break; 1058 case OOB: 1059 // client already provided OOB data, let's skip notification. 1060 break; 1061 } 1062 } 1063 1064 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1065 int recv_flags; 1066 if (sm_conn->sm_role){ 1067 // slave / responder 1068 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1069 } else { 1070 // master / initiator 1071 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1072 } 1073 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1074 return recv_flags == setup->sm_key_distribution_received_set; 1075 } 1076 1077 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1078 if (sm_active_connection == con_handle){ 1079 sm_timeout_stop(); 1080 sm_active_connection = 0; 1081 log_info("sm: connection 0x%x released setup context", con_handle); 1082 } 1083 } 1084 1085 static int sm_key_distribution_flags_for_auth_req(void){ 1086 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1087 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1088 // encryption information only if bonding requested 1089 flags |= SM_KEYDIST_ENC_KEY; 1090 } 1091 return flags; 1092 } 1093 1094 static void sm_init_setup(sm_connection_t * sm_conn){ 1095 1096 // fill in sm setup 1097 sm_reset_tk(); 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 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1127 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1128 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1129 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1130 } 1131 1132 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1133 1134 sm_pairing_packet_t * remote_packet; 1135 int remote_key_request; 1136 if (sm_conn->sm_role){ 1137 // slave / responder 1138 remote_packet = &setup->sm_m_preq; 1139 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1140 } else { 1141 // master / initiator 1142 remote_packet = &setup->sm_s_pres; 1143 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1144 } 1145 1146 // check key size 1147 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1148 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1149 1150 // decide on STK generation method 1151 sm_setup_tk(); 1152 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1153 1154 // check if STK generation method is acceptable by client 1155 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1156 1157 // identical to responder 1158 sm_setup_key_distribution(remote_key_request); 1159 1160 // JUST WORKS doens't provide authentication 1161 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1162 1163 return 0; 1164 } 1165 1166 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1167 1168 // cache and reset context 1169 int matched_device_id = sm_address_resolution_test; 1170 address_resolution_mode_t mode = sm_address_resolution_mode; 1171 void * context = sm_address_resolution_context; 1172 1173 // reset context 1174 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1175 sm_address_resolution_context = NULL; 1176 sm_address_resolution_test = -1; 1177 hci_con_handle_t con_handle = 0; 1178 1179 sm_connection_t * sm_connection; 1180 uint16_t ediv; 1181 switch (mode){ 1182 case ADDRESS_RESOLUTION_GENERAL: 1183 break; 1184 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1185 sm_connection = (sm_connection_t *) context; 1186 con_handle = sm_connection->sm_handle; 1187 switch (event){ 1188 case ADDRESS_RESOLUTION_SUCEEDED: 1189 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1190 sm_connection->sm_le_db_index = matched_device_id; 1191 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1192 if (sm_connection->sm_role) break; 1193 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1194 sm_connection->sm_security_request_received = 0; 1195 sm_connection->sm_bonding_requested = 0; 1196 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1197 if (ediv){ 1198 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1199 } else { 1200 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1201 } 1202 break; 1203 case ADDRESS_RESOLUTION_FAILED: 1204 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1205 if (sm_connection->sm_role) break; 1206 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1207 sm_connection->sm_security_request_received = 0; 1208 sm_connection->sm_bonding_requested = 0; 1209 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1210 break; 1211 } 1212 break; 1213 default: 1214 break; 1215 } 1216 1217 switch (event){ 1218 case ADDRESS_RESOLUTION_SUCEEDED: 1219 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1220 break; 1221 case ADDRESS_RESOLUTION_FAILED: 1222 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1223 break; 1224 } 1225 } 1226 1227 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1228 1229 int le_db_index = -1; 1230 1231 // lookup device based on IRK 1232 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1233 int i; 1234 for (i=0; i < le_device_db_count(); i++){ 1235 sm_key_t irk; 1236 bd_addr_t address; 1237 int address_type; 1238 le_device_db_info(i, &address_type, address, irk); 1239 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1240 log_info("sm: device found for IRK, updating"); 1241 le_db_index = i; 1242 break; 1243 } 1244 } 1245 } 1246 1247 // if not found, lookup via public address if possible 1248 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1249 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1250 int i; 1251 for (i=0; i < le_device_db_count(); i++){ 1252 bd_addr_t address; 1253 int address_type; 1254 le_device_db_info(i, &address_type, address, NULL); 1255 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1256 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1257 log_info("sm: device found for public address, updating"); 1258 le_db_index = i; 1259 break; 1260 } 1261 } 1262 } 1263 1264 // if not found, add to db 1265 if (le_db_index < 0) { 1266 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1267 } 1268 1269 if (le_db_index >= 0){ 1270 le_device_db_local_counter_set(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 1287 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1288 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1289 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1290 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1291 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1292 } 1293 } 1294 1295 // keep le_db_index 1296 sm_conn->sm_le_db_index = le_db_index; 1297 } 1298 1299 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1300 setup->sm_pairing_failed_reason = reason; 1301 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1302 } 1303 1304 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1305 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1306 } 1307 1308 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1309 1310 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1311 1312 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1313 if (sm_conn->sm_role){ 1314 // Responder 1315 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1316 } else { 1317 // Initiator role 1318 switch (setup->sm_stk_generation_method){ 1319 case JUST_WORKS: 1320 sm_sc_prepare_dhkey_check(sm_conn); 1321 break; 1322 1323 case NK_BOTH_INPUT: { 1324 // calc Va if numeric comparison 1325 // TODO: use AES Engine to calculate g2 1326 uint8_t value[32]; 1327 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1328 uint32_t va = g2(value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce) % 1000000; 1329 big_endian_store_32(setup->sm_tk, 12, va); 1330 sm_trigger_user_response(sm_conn); 1331 break; 1332 } 1333 case PK_INIT_INPUT: 1334 case PK_RESP_INPUT: 1335 case OK_BOTH_INPUT: 1336 if (setup->sm_passkey_bit < 20) { 1337 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1338 } else { 1339 sm_sc_prepare_dhkey_check(sm_conn); 1340 } 1341 break; 1342 case OOB: 1343 // TODO: implement SC OOB 1344 break; 1345 } 1346 } 1347 } 1348 1349 static void sm_sc_state_after_receiving_dhkey_check(sm_connection_t * sm_conn){ 1350 if (sm_conn->sm_role){ 1351 // responder 1352 // for numeric comparison, we need to wait for user confirm 1353 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 1354 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1355 } else { 1356 sm_sc_prepare_dhkey_check(sm_conn); 1357 } 1358 } else { 1359 // initiator 1360 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1361 } 1362 } 1363 1364 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1365 return sm_cmac_sc_buffer[offset]; 1366 } 1367 1368 static void sm_sc_cmac_done(uint8_t * hash){ 1369 log_info("sm_sc_cmac_done: "); 1370 log_info_hexdump(hash, 16); 1371 1372 switch (sm_cmac_connection->sm_engine_state){ 1373 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1374 memcpy(setup->sm_local_confirm, hash, 16); 1375 sm_cmac_connection->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1376 break; 1377 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1378 // check 1379 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1380 sm_pairing_error(sm_cmac_connection, SM_REASON_CONFIRM_VALUE_FAILED); 1381 break; 1382 } 1383 sm_sc_state_after_receiving_random(sm_cmac_connection); 1384 break; 1385 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1386 memcpy(setup->sm_local_dhkey_check, hash, 16); 1387 sm_cmac_connection->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1388 break; 1389 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1390 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1391 sm_pairing_error(sm_cmac_connection, SM_REASON_DHKEY_CHECK_FAILED); 1392 break; 1393 } 1394 sm_sc_state_after_receiving_dhkey_check(sm_cmac_connection); 1395 break; 1396 case SM_SC_W4_CALCULATE_F5_SALT: 1397 memcpy(setup->sm_t, hash, 16); 1398 sm_cmac_connection->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1399 break; 1400 case SM_SC_W4_CALCULATE_F5_MACKEY: 1401 memcpy(setup->sm_mackey, hash, 16); 1402 sm_cmac_connection->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1403 break; 1404 case SM_SC_W4_CALCULATE_F5_LTK: 1405 memcpy(setup->sm_ltk, hash, 16); 1406 sm_cmac_connection->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1407 break; 1408 default: 1409 log_error("sm_sc_cmac_done in state %u", sm_cmac_connection->sm_engine_state); 1410 break; 1411 } 1412 sm_cmac_connection = 0; 1413 sm_run(); 1414 } 1415 1416 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){ 1417 const uint16_t message_len = 65; 1418 sm_cmac_connection = sm_conn; 1419 memcpy(sm_cmac_sc_buffer, u, 32); 1420 memcpy(sm_cmac_sc_buffer+32, v, 32); 1421 sm_cmac_sc_buffer[64] = z; 1422 log_info("f4 key"); 1423 log_info_hexdump(x, 16); 1424 log_info("f4 message"); 1425 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1426 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1427 } 1428 1429 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1430 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1431 static const uint8_t f5_length[] = { 0x01, 0x00}; 1432 1433 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1434 #ifdef USE_MBEDTLS_FOR_ECDH 1435 // da * Pb 1436 mbedtls_ecp_group grp; 1437 mbedtls_ecp_group_init( &grp ); 1438 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1439 mbedtls_ecp_point Q; 1440 mbedtls_ecp_point_init( &Q ); 1441 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1442 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1443 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1444 mbedtls_ecp_point DH; 1445 mbedtls_ecp_point_init( &DH ); 1446 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1447 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1448 #endif 1449 log_info("dhkey"); 1450 log_info_hexdump(dhkey, 32); 1451 } 1452 1453 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1454 // calculate DHKEY 1455 sm_key256_t dhkey; 1456 sm_sc_calculate_dhkey(dhkey); 1457 1458 // calculate salt for f5 1459 const uint16_t message_len = 32; 1460 sm_cmac_connection = sm_conn; 1461 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1462 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1463 } 1464 1465 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){ 1466 const uint16_t message_len = 53; 1467 sm_cmac_connection = sm_conn; 1468 1469 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1470 sm_cmac_sc_buffer[0] = 0; 1471 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1472 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1473 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1474 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1475 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1476 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1477 log_info("f5 key"); 1478 log_info_hexdump(t, 16); 1479 log_info("f5 message for MacKey"); 1480 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1481 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1482 } 1483 1484 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1485 sm_key56_t bd_addr_master, bd_addr_slave; 1486 bd_addr_master[0] = setup->sm_m_addr_type; 1487 bd_addr_slave[0] = setup->sm_s_addr_type; 1488 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1489 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1490 if (sm_conn->sm_role){ 1491 // responder 1492 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1493 } else { 1494 // initiator 1495 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1496 } 1497 } 1498 1499 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1500 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1501 const uint16_t message_len = 53; 1502 sm_cmac_connection = sm_conn; 1503 sm_cmac_sc_buffer[0] = 1; 1504 // 1..52 setup before 1505 log_info("f5 key"); 1506 log_info_hexdump(t, 16); 1507 log_info("f5 message for LTK"); 1508 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1509 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1510 } 1511 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1512 f5_ltk(sm_conn, setup->sm_t); 1513 } 1514 1515 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){ 1516 const uint16_t message_len = 65; 1517 sm_cmac_connection = sm_conn; 1518 memcpy(sm_cmac_sc_buffer, n1, 16); 1519 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1520 memcpy(sm_cmac_sc_buffer+32, r, 16); 1521 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1522 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1523 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1524 log_info("f6 key"); 1525 log_info_hexdump(w, 16); 1526 log_info("f6 message"); 1527 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1528 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1529 } 1530 1531 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1532 uint8_t z = 0; 1533 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1534 // some form of passkey 1535 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1536 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1537 setup->sm_passkey_bit++; 1538 } 1539 #ifdef USE_MBEDTLS_FOR_ECDH 1540 uint8_t local_qx[32]; 1541 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1542 #endif 1543 f4_engine(sm_conn, local_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1544 } 1545 1546 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1547 uint8_t z = 0; 1548 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1549 // some form of passkey 1550 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1551 // sm_passkey_bit was increased before sending confirm value 1552 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1553 } 1554 #ifdef USE_MBEDTLS_FOR_ECDH 1555 uint8_t local_qx[32]; 1556 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1557 #endif 1558 f4_engine(sm_conn, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 1559 } 1560 1561 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1562 1563 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1564 1565 // TODO: use AES CMAC Engine 1566 // sm_sc_calculate_f5_for_dhkey_check(sm_conn); 1567 1568 // second part 1569 // sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1570 } 1571 1572 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1573 // calculate DHKCheck 1574 sm_key56_t bd_addr_master, bd_addr_slave; 1575 bd_addr_master[0] = setup->sm_m_addr_type; 1576 bd_addr_slave[0] = setup->sm_s_addr_type; 1577 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1578 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1579 uint8_t iocap_a[3]; 1580 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1581 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1582 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1583 uint8_t iocap_b[3]; 1584 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1585 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1586 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1587 if (sm_conn->sm_role){ 1588 // responder 1589 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); 1590 } else { 1591 // initiator 1592 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); 1593 } 1594 } 1595 1596 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1597 // validate E = f6() 1598 sm_key56_t bd_addr_master, bd_addr_slave; 1599 bd_addr_master[0] = setup->sm_m_addr_type; 1600 bd_addr_slave[0] = setup->sm_s_addr_type; 1601 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1602 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1603 1604 uint8_t iocap_a[3]; 1605 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1606 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1607 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1608 uint8_t iocap_b[3]; 1609 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1610 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1611 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1612 if (sm_conn->sm_role){ 1613 // responder 1614 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); 1615 } else { 1616 // initiator 1617 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); 1618 } 1619 } 1620 1621 #endif 1622 1623 static void sm_run(void){ 1624 1625 btstack_linked_list_iterator_t it; 1626 1627 // assert that we can send at least commands 1628 if (!hci_can_send_command_packet_now()) return; 1629 1630 // 1631 // non-connection related behaviour 1632 // 1633 1634 // distributed key generation 1635 switch (dkg_state){ 1636 case DKG_CALC_IRK: 1637 // already busy? 1638 if (sm_aes128_state == SM_AES128_IDLE) { 1639 // IRK = d1(IR, 1, 0) 1640 sm_key_t d1_prime; 1641 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1642 dkg_next_state(); 1643 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1644 return; 1645 } 1646 break; 1647 case DKG_CALC_DHK: 1648 // already busy? 1649 if (sm_aes128_state == SM_AES128_IDLE) { 1650 // DHK = d1(IR, 3, 0) 1651 sm_key_t d1_prime; 1652 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1653 dkg_next_state(); 1654 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1655 return; 1656 } 1657 break; 1658 default: 1659 break; 1660 } 1661 1662 // random address updates 1663 switch (rau_state){ 1664 case RAU_GET_RANDOM: 1665 rau_next_state(); 1666 sm_random_start(NULL); 1667 return; 1668 case RAU_GET_ENC: 1669 // already busy? 1670 if (sm_aes128_state == SM_AES128_IDLE) { 1671 sm_key_t r_prime; 1672 sm_ah_r_prime(sm_random_address, r_prime); 1673 rau_next_state(); 1674 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1675 return; 1676 } 1677 break; 1678 case RAU_SET_ADDRESS: 1679 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1680 rau_state = RAU_IDLE; 1681 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1682 return; 1683 default: 1684 break; 1685 } 1686 1687 // CMAC 1688 switch (sm_cmac_state){ 1689 case CMAC_CALC_SUBKEYS: 1690 case CMAC_CALC_MI: 1691 case CMAC_CALC_MLAST: 1692 // already busy? 1693 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1694 sm_cmac_handle_aes_engine_ready(); 1695 return; 1696 default: 1697 break; 1698 } 1699 1700 // CSRK Lookup 1701 // -- if csrk lookup ready, find connection that require csrk lookup 1702 if (sm_address_resolution_idle()){ 1703 hci_connections_get_iterator(&it); 1704 while(btstack_linked_list_iterator_has_next(&it)){ 1705 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1706 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1707 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1708 // and start lookup 1709 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); 1710 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1711 break; 1712 } 1713 } 1714 } 1715 1716 // -- if csrk lookup ready, resolved addresses for received addresses 1717 if (sm_address_resolution_idle()) { 1718 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1719 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1720 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1721 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1722 btstack_memory_sm_lookup_entry_free(entry); 1723 } 1724 } 1725 1726 // -- Continue with CSRK device lookup by public or resolvable private address 1727 if (!sm_address_resolution_idle()){ 1728 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1729 while (sm_address_resolution_test < le_device_db_count()){ 1730 int addr_type; 1731 bd_addr_t addr; 1732 sm_key_t irk; 1733 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1734 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1735 1736 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1737 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1738 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1739 break; 1740 } 1741 1742 if (sm_address_resolution_addr_type == 0){ 1743 sm_address_resolution_test++; 1744 continue; 1745 } 1746 1747 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1748 1749 log_info("LE Device Lookup: calculate AH"); 1750 log_info_key("IRK", irk); 1751 1752 sm_key_t r_prime; 1753 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1754 sm_address_resolution_ah_calculation_active = 1; 1755 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1756 return; 1757 } 1758 1759 if (sm_address_resolution_test >= le_device_db_count()){ 1760 log_info("LE Device Lookup: not found"); 1761 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1762 } 1763 } 1764 1765 1766 // 1767 // active connection handling 1768 // -- use loop to handle next connection if lock on setup context is released 1769 1770 while (1) { 1771 1772 // Find connections that requires setup context and make active if no other is locked 1773 hci_connections_get_iterator(&it); 1774 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1775 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1776 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1777 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1778 int done = 1; 1779 int err; 1780 int encryption_key_size; 1781 int authenticated; 1782 int authorized; 1783 switch (sm_connection->sm_engine_state) { 1784 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1785 // send packet if possible, 1786 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1787 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1788 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1789 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1790 } else { 1791 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1792 } 1793 // don't lock setup context yet 1794 done = 0; 1795 break; 1796 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1797 sm_init_setup(sm_connection); 1798 // recover pairing request 1799 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1800 err = sm_stk_generation_init(sm_connection); 1801 if (err){ 1802 setup->sm_pairing_failed_reason = err; 1803 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1804 break; 1805 } 1806 sm_timeout_start(sm_connection); 1807 // generate random number first, if we need to show passkey 1808 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1809 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1810 break; 1811 } 1812 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1813 break; 1814 case SM_INITIATOR_PH0_HAS_LTK: 1815 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1816 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1817 &encryption_key_size, &authenticated, &authorized); 1818 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1819 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1820 sm_connection->sm_connection_authenticated = authenticated; 1821 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1822 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1823 break; 1824 case SM_RESPONDER_PH0_RECEIVED_LTK: 1825 // re-establish previously used LTK using Rand and EDIV 1826 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1827 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1828 // re-establish used key encryption size 1829 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1830 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1831 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1832 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1833 log_info("sm: received ltk request with key size %u, authenticated %u", 1834 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1835 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1836 break; 1837 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1838 sm_init_setup(sm_connection); 1839 sm_timeout_start(sm_connection); 1840 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1841 break; 1842 default: 1843 done = 0; 1844 break; 1845 } 1846 if (done){ 1847 sm_active_connection = sm_connection->sm_handle; 1848 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1849 } 1850 } 1851 1852 // 1853 // active connection handling 1854 // 1855 1856 if (sm_active_connection == 0) return; 1857 1858 // assert that we could send a SM PDU - not needed for all of the following 1859 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1860 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1861 return; 1862 } 1863 1864 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1865 if (!connection) return; 1866 1867 sm_key_t plaintext; 1868 int key_distribution_flags; 1869 1870 log_info("sm_run: state %u", connection->sm_engine_state); 1871 1872 // responding state 1873 switch (connection->sm_engine_state){ 1874 1875 // general 1876 case SM_GENERAL_SEND_PAIRING_FAILED: { 1877 uint8_t buffer[2]; 1878 buffer[0] = SM_CODE_PAIRING_FAILED; 1879 buffer[1] = setup->sm_pairing_failed_reason; 1880 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1881 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1882 sm_done_for_handle(connection->sm_handle); 1883 break; 1884 } 1885 1886 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1887 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1888 if (!sm_cmac_ready()) break; 1889 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1890 sm_sc_calculate_local_confirm(connection); 1891 break; 1892 1893 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 1894 if (!sm_cmac_ready()) break; 1895 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 1896 sm_sc_calculate_remote_confirm(connection); 1897 break; 1898 1899 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 1900 if (!sm_cmac_ready()) break; 1901 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 1902 sm_sc_calculate_f6_for_dhkey_check(connection); 1903 break; 1904 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1905 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1906 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 1907 break; 1908 case SM_SC_W2_CALCULATE_F5_SALT: 1909 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 1910 f5_calculate_salt(connection); 1911 break; 1912 case SM_SC_W2_CALCULATE_F5_MACKEY: 1913 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 1914 f5_calculate_mackey(connection); 1915 break; 1916 case SM_SC_W2_CALCULATE_F5_LTK: 1917 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 1918 f5_calculate_ltk(connection); 1919 break; 1920 #endif 1921 // initiator side 1922 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1923 sm_key_t peer_ltk_flipped; 1924 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1925 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1926 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1927 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1928 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1929 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1930 return; 1931 } 1932 1933 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1934 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1935 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1936 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1937 sm_timeout_reset(connection); 1938 break; 1939 1940 // responder side 1941 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1942 connection->sm_engine_state = SM_RESPONDER_IDLE; 1943 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1944 return; 1945 1946 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1947 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1948 uint8_t buffer[65]; 1949 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1950 // 1951 #ifdef USE_MBEDTLS_FOR_ECDH 1952 uint8_t value[32]; 1953 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1954 reverse_256(value, &buffer[1]); 1955 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1956 reverse_256(value, &buffer[33]); 1957 #endif 1958 // TODO: use random generator to generate nonce 1959 1960 // generate 128-bit nonce 1961 int i; 1962 for (i=0;i<16;i++){ 1963 setup->sm_local_nonce[i] = rand() & 0xff; 1964 } 1965 1966 // stk generation method 1967 // passkey entry: notify app to show passkey or to request passkey 1968 switch (setup->sm_stk_generation_method){ 1969 case JUST_WORKS: 1970 case NK_BOTH_INPUT: 1971 if (connection->sm_role){ 1972 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1973 } else { 1974 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1975 } 1976 break; 1977 case PK_INIT_INPUT: 1978 case PK_RESP_INPUT: 1979 case OK_BOTH_INPUT: 1980 // hack for testing: assume user entered '000000' 1981 // memset(setup->sm_tk, 0, 16); 1982 memcpy(setup->sm_ra, setup->sm_tk, 16); 1983 memcpy(setup->sm_rb, setup->sm_tk, 16); 1984 setup->sm_passkey_bit = 0; 1985 if (connection->sm_role){ 1986 // responder 1987 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1988 } else { 1989 // initiator 1990 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1991 } 1992 sm_trigger_user_response(connection); 1993 break; 1994 case OOB: 1995 // TODO: implement SC OOB 1996 break; 1997 } 1998 1999 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2000 sm_timeout_reset(connection); 2001 break; 2002 } 2003 case SM_SC_SEND_CONFIRMATION: { 2004 uint8_t buffer[17]; 2005 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2006 reverse_128(setup->sm_local_confirm, &buffer[1]); 2007 if (connection->sm_role){ 2008 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2009 } else { 2010 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2011 } 2012 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2013 sm_timeout_reset(connection); 2014 break; 2015 } 2016 case SM_SC_SEND_PAIRING_RANDOM: { 2017 uint8_t buffer[17]; 2018 buffer[0] = SM_CODE_PAIRING_RANDOM; 2019 reverse_128(setup->sm_local_nonce, &buffer[1]); 2020 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2021 if (connection->sm_role){ 2022 // responder 2023 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2024 } else { 2025 // initiator 2026 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2027 } 2028 } else { 2029 if (connection->sm_role){ 2030 // responder 2031 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2032 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2033 // calc Vb if numeric comparison 2034 // TODO: use AES Engine to calculate g2 2035 uint8_t value[32]; 2036 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2037 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 2038 big_endian_store_32(setup->sm_tk, 12, vb); 2039 sm_trigger_user_response(connection); 2040 } 2041 } else { 2042 // initiator 2043 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2044 } 2045 } 2046 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2047 sm_timeout_reset(connection); 2048 break; 2049 } 2050 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2051 uint8_t buffer[17]; 2052 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2053 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2054 2055 if (connection->sm_role){ 2056 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2057 } else { 2058 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2059 } 2060 2061 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2062 sm_timeout_reset(connection); 2063 break; 2064 } 2065 2066 #endif 2067 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2068 // echo initiator for now 2069 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2070 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2071 2072 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2073 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2074 if (setup->sm_use_secure_connections){ 2075 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2076 // skip LTK/EDIV for SC 2077 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2078 } 2079 #endif 2080 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); 2081 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); 2082 2083 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2084 sm_timeout_reset(connection); 2085 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2086 if (setup->sm_stk_generation_method == JUST_WORKS){ 2087 sm_trigger_user_response(connection); 2088 } 2089 return; 2090 2091 case SM_PH2_SEND_PAIRING_RANDOM: { 2092 uint8_t buffer[17]; 2093 buffer[0] = SM_CODE_PAIRING_RANDOM; 2094 reverse_128(setup->sm_local_random, &buffer[1]); 2095 if (connection->sm_role){ 2096 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2097 } else { 2098 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2099 } 2100 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2101 sm_timeout_reset(connection); 2102 break; 2103 } 2104 2105 case SM_PH2_GET_RANDOM_TK: 2106 case SM_PH2_C1_GET_RANDOM_A: 2107 case SM_PH2_C1_GET_RANDOM_B: 2108 case SM_PH3_GET_RANDOM: 2109 case SM_PH3_GET_DIV: 2110 sm_next_responding_state(connection); 2111 sm_random_start(connection); 2112 return; 2113 2114 case SM_PH2_C1_GET_ENC_B: 2115 case SM_PH2_C1_GET_ENC_D: 2116 // already busy? 2117 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2118 sm_next_responding_state(connection); 2119 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2120 return; 2121 2122 case SM_PH3_LTK_GET_ENC: 2123 case SM_RESPONDER_PH4_LTK_GET_ENC: 2124 // already busy? 2125 if (sm_aes128_state == SM_AES128_IDLE) { 2126 sm_key_t d_prime; 2127 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2128 sm_next_responding_state(connection); 2129 sm_aes128_start(sm_persistent_er, d_prime, connection); 2130 return; 2131 } 2132 break; 2133 2134 case SM_PH3_CSRK_GET_ENC: 2135 // already busy? 2136 if (sm_aes128_state == SM_AES128_IDLE) { 2137 sm_key_t d_prime; 2138 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2139 sm_next_responding_state(connection); 2140 sm_aes128_start(sm_persistent_er, d_prime, connection); 2141 return; 2142 } 2143 break; 2144 2145 case SM_PH2_C1_GET_ENC_C: 2146 // already busy? 2147 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2148 // calculate m_confirm using aes128 engine - step 1 2149 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); 2150 sm_next_responding_state(connection); 2151 sm_aes128_start(setup->sm_tk, plaintext, connection); 2152 break; 2153 case SM_PH2_C1_GET_ENC_A: 2154 // already busy? 2155 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2156 // calculate confirm using aes128 engine - step 1 2157 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); 2158 sm_next_responding_state(connection); 2159 sm_aes128_start(setup->sm_tk, plaintext, connection); 2160 break; 2161 case SM_PH2_CALC_STK: 2162 // already busy? 2163 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2164 // calculate STK 2165 if (connection->sm_role){ 2166 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2167 } else { 2168 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2169 } 2170 sm_next_responding_state(connection); 2171 sm_aes128_start(setup->sm_tk, plaintext, connection); 2172 break; 2173 case SM_PH3_Y_GET_ENC: 2174 // already busy? 2175 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2176 // PH3B2 - calculate Y from - enc 2177 // Y = dm(DHK, Rand) 2178 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2179 sm_next_responding_state(connection); 2180 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2181 return; 2182 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2183 uint8_t buffer[17]; 2184 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2185 reverse_128(setup->sm_local_confirm, &buffer[1]); 2186 if (connection->sm_role){ 2187 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2188 } else { 2189 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2190 } 2191 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2192 sm_timeout_reset(connection); 2193 return; 2194 } 2195 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2196 sm_key_t stk_flipped; 2197 reverse_128(setup->sm_ltk, stk_flipped); 2198 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2199 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2200 return; 2201 } 2202 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2203 sm_key_t stk_flipped; 2204 reverse_128(setup->sm_ltk, stk_flipped); 2205 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2206 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2207 return; 2208 } 2209 case SM_RESPONDER_PH4_SEND_LTK: { 2210 sm_key_t ltk_flipped; 2211 reverse_128(setup->sm_ltk, ltk_flipped); 2212 connection->sm_engine_state = SM_RESPONDER_IDLE; 2213 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2214 return; 2215 } 2216 case SM_RESPONDER_PH4_Y_GET_ENC: 2217 // already busy? 2218 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2219 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2220 // Y = dm(DHK, Rand) 2221 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2222 sm_next_responding_state(connection); 2223 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2224 return; 2225 2226 case SM_PH3_DISTRIBUTE_KEYS: 2227 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2228 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2229 uint8_t buffer[17]; 2230 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2231 reverse_128(setup->sm_ltk, &buffer[1]); 2232 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2233 sm_timeout_reset(connection); 2234 return; 2235 } 2236 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2237 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2238 uint8_t buffer[11]; 2239 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2240 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2241 reverse_64(setup->sm_local_rand, &buffer[3]); 2242 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2243 sm_timeout_reset(connection); 2244 return; 2245 } 2246 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2247 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2248 uint8_t buffer[17]; 2249 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2250 reverse_128(sm_persistent_irk, &buffer[1]); 2251 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2252 sm_timeout_reset(connection); 2253 return; 2254 } 2255 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2256 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2257 bd_addr_t local_address; 2258 uint8_t buffer[8]; 2259 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2260 gap_advertisements_get_address(&buffer[1], local_address); 2261 reverse_bd_addr(local_address, &buffer[2]); 2262 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2263 sm_timeout_reset(connection); 2264 return; 2265 } 2266 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2267 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2268 2269 // hack to reproduce test runs 2270 if (test_use_fixed_local_csrk){ 2271 memset(setup->sm_local_csrk, 0xcc, 16); 2272 } 2273 2274 uint8_t buffer[17]; 2275 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2276 reverse_128(setup->sm_local_csrk, &buffer[1]); 2277 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2278 sm_timeout_reset(connection); 2279 return; 2280 } 2281 2282 // keys are sent 2283 if (connection->sm_role){ 2284 // slave -> receive master keys if any 2285 if (sm_key_distribution_all_received(connection)){ 2286 sm_key_distribution_handle_all_received(connection); 2287 connection->sm_engine_state = SM_RESPONDER_IDLE; 2288 sm_done_for_handle(connection->sm_handle); 2289 } else { 2290 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2291 } 2292 } else { 2293 // master -> all done 2294 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2295 sm_done_for_handle(connection->sm_handle); 2296 } 2297 break; 2298 2299 default: 2300 break; 2301 } 2302 2303 // check again if active connection was released 2304 if (sm_active_connection) break; 2305 } 2306 } 2307 2308 // note: aes engine is ready as we just got the aes result 2309 static void sm_handle_encryption_result(uint8_t * data){ 2310 2311 sm_aes128_state = SM_AES128_IDLE; 2312 2313 if (sm_address_resolution_ah_calculation_active){ 2314 sm_address_resolution_ah_calculation_active = 0; 2315 // compare calulated address against connecting device 2316 uint8_t hash[3]; 2317 reverse_24(data, hash); 2318 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2319 log_info("LE Device Lookup: matched resolvable private address"); 2320 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2321 return; 2322 } 2323 // no match, try next 2324 sm_address_resolution_test++; 2325 return; 2326 } 2327 2328 switch (dkg_state){ 2329 case DKG_W4_IRK: 2330 reverse_128(data, sm_persistent_irk); 2331 log_info_key("irk", sm_persistent_irk); 2332 dkg_next_state(); 2333 return; 2334 case DKG_W4_DHK: 2335 reverse_128(data, sm_persistent_dhk); 2336 log_info_key("dhk", sm_persistent_dhk); 2337 dkg_next_state(); 2338 // SM Init Finished 2339 return; 2340 default: 2341 break; 2342 } 2343 2344 switch (rau_state){ 2345 case RAU_W4_ENC: 2346 reverse_24(data, &sm_random_address[3]); 2347 rau_next_state(); 2348 return; 2349 default: 2350 break; 2351 } 2352 2353 switch (sm_cmac_state){ 2354 case CMAC_W4_SUBKEYS: 2355 case CMAC_W4_MI: 2356 case CMAC_W4_MLAST: 2357 { 2358 sm_key_t t; 2359 reverse_128(data, t); 2360 sm_cmac_handle_encryption_result(t); 2361 } 2362 return; 2363 default: 2364 break; 2365 } 2366 2367 // retrieve sm_connection provided to sm_aes128_start_encryption 2368 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2369 if (!connection) return; 2370 switch (connection->sm_engine_state){ 2371 case SM_PH2_C1_W4_ENC_A: 2372 case SM_PH2_C1_W4_ENC_C: 2373 { 2374 sm_key_t t2; 2375 reverse_128(data, t2); 2376 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2377 } 2378 sm_next_responding_state(connection); 2379 return; 2380 case SM_PH2_C1_W4_ENC_B: 2381 reverse_128(data, setup->sm_local_confirm); 2382 log_info_key("c1!", setup->sm_local_confirm); 2383 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2384 return; 2385 case SM_PH2_C1_W4_ENC_D: 2386 { 2387 sm_key_t peer_confirm_test; 2388 reverse_128(data, peer_confirm_test); 2389 log_info_key("c1!", peer_confirm_test); 2390 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2391 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2392 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2393 return; 2394 } 2395 if (connection->sm_role){ 2396 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2397 } else { 2398 connection->sm_engine_state = SM_PH2_CALC_STK; 2399 } 2400 } 2401 return; 2402 case SM_PH2_W4_STK: 2403 reverse_128(data, setup->sm_ltk); 2404 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2405 log_info_key("stk", setup->sm_ltk); 2406 if (connection->sm_role){ 2407 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2408 } else { 2409 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2410 } 2411 return; 2412 case SM_PH3_Y_W4_ENC:{ 2413 sm_key_t y128; 2414 reverse_128(data, y128); 2415 setup->sm_local_y = big_endian_read_16(y128, 14); 2416 log_info_hex16("y", setup->sm_local_y); 2417 // PH3B3 - calculate EDIV 2418 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2419 log_info_hex16("ediv", setup->sm_local_ediv); 2420 // PH3B4 - calculate LTK - enc 2421 // LTK = d1(ER, DIV, 0)) 2422 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2423 return; 2424 } 2425 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2426 sm_key_t y128; 2427 reverse_128(data, y128); 2428 setup->sm_local_y = big_endian_read_16(y128, 14); 2429 log_info_hex16("y", setup->sm_local_y); 2430 2431 // PH3B3 - calculate DIV 2432 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2433 log_info_hex16("ediv", setup->sm_local_ediv); 2434 // PH3B4 - calculate LTK - enc 2435 // LTK = d1(ER, DIV, 0)) 2436 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2437 return; 2438 } 2439 case SM_PH3_LTK_W4_ENC: 2440 reverse_128(data, setup->sm_ltk); 2441 log_info_key("ltk", setup->sm_ltk); 2442 // calc CSRK next 2443 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2444 return; 2445 case SM_PH3_CSRK_W4_ENC: 2446 reverse_128(data, setup->sm_local_csrk); 2447 log_info_key("csrk", setup->sm_local_csrk); 2448 if (setup->sm_key_distribution_send_set){ 2449 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2450 } else { 2451 // no keys to send, just continue 2452 if (connection->sm_role){ 2453 // slave -> receive master keys 2454 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2455 } else { 2456 // master -> all done 2457 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2458 sm_done_for_handle(connection->sm_handle); 2459 } 2460 } 2461 return; 2462 case SM_RESPONDER_PH4_LTK_W4_ENC: 2463 reverse_128(data, setup->sm_ltk); 2464 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2465 log_info_key("ltk", setup->sm_ltk); 2466 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2467 return; 2468 default: 2469 break; 2470 } 2471 } 2472 2473 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2474 static void sm_handle_random_result(uint8_t * data){ 2475 2476 switch (rau_state){ 2477 case RAU_W4_RANDOM: 2478 // non-resolvable vs. resolvable 2479 switch (gap_random_adress_type){ 2480 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2481 // resolvable: use random as prand and calc address hash 2482 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2483 memcpy(sm_random_address, data, 3); 2484 sm_random_address[0] &= 0x3f; 2485 sm_random_address[0] |= 0x40; 2486 rau_state = RAU_GET_ENC; 2487 break; 2488 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2489 default: 2490 // "The two most significant bits of the address shall be equal to ‘0’"" 2491 memcpy(sm_random_address, data, 6); 2492 sm_random_address[0] &= 0x3f; 2493 rau_state = RAU_SET_ADDRESS; 2494 break; 2495 } 2496 return; 2497 default: 2498 break; 2499 } 2500 2501 // retrieve sm_connection provided to sm_random_start 2502 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2503 if (!connection) return; 2504 switch (connection->sm_engine_state){ 2505 case SM_PH2_W4_RANDOM_TK: 2506 { 2507 // map random to 0-999999 without speding much cycles on a modulus operation 2508 uint32_t tk = little_endian_read_32(data,0); 2509 tk = tk & 0xfffff; // 1048575 2510 if (tk >= 999999){ 2511 tk = tk - 999999; 2512 } 2513 sm_reset_tk(); 2514 big_endian_store_32(setup->sm_tk, 12, tk); 2515 if (connection->sm_role){ 2516 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2517 } else { 2518 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2519 sm_trigger_user_response(connection); 2520 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2521 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2522 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2523 } 2524 } 2525 return; 2526 } 2527 case SM_PH2_C1_W4_RANDOM_A: 2528 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2529 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2530 return; 2531 case SM_PH2_C1_W4_RANDOM_B: 2532 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2533 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2534 return; 2535 case SM_PH3_W4_RANDOM: 2536 reverse_64(data, setup->sm_local_rand); 2537 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2538 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2539 // no db for authenticated flag hack: store flag in bit 4 of LSB 2540 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2541 connection->sm_engine_state = SM_PH3_GET_DIV; 2542 return; 2543 case SM_PH3_W4_DIV: 2544 // use 16 bit from random value as div 2545 setup->sm_local_div = big_endian_read_16(data, 0); 2546 log_info_hex16("div", setup->sm_local_div); 2547 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2548 return; 2549 default: 2550 break; 2551 } 2552 } 2553 2554 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2555 2556 sm_connection_t * sm_conn; 2557 hci_con_handle_t con_handle; 2558 2559 switch (packet_type) { 2560 2561 case HCI_EVENT_PACKET: 2562 switch (hci_event_packet_get_type(packet)) { 2563 2564 case BTSTACK_EVENT_STATE: 2565 // bt stack activated, get started 2566 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2567 log_info("HCI Working!"); 2568 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2569 rau_state = RAU_IDLE; 2570 sm_run(); 2571 } 2572 break; 2573 2574 case HCI_EVENT_LE_META: 2575 switch (packet[2]) { 2576 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2577 2578 log_info("sm: connected"); 2579 2580 if (packet[3]) return; // connection failed 2581 2582 con_handle = little_endian_read_16(packet, 4); 2583 sm_conn = sm_get_connection_for_handle(con_handle); 2584 if (!sm_conn) break; 2585 2586 sm_conn->sm_handle = con_handle; 2587 sm_conn->sm_role = packet[6]; 2588 sm_conn->sm_peer_addr_type = packet[7]; 2589 reverse_bd_addr(&packet[8], 2590 sm_conn->sm_peer_address); 2591 2592 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2593 2594 // reset security properties 2595 sm_conn->sm_connection_encrypted = 0; 2596 sm_conn->sm_connection_authenticated = 0; 2597 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2598 sm_conn->sm_le_db_index = -1; 2599 2600 // prepare CSRK lookup (does not involve setup) 2601 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2602 2603 // just connected -> everything else happens in sm_run() 2604 if (sm_conn->sm_role){ 2605 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2606 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2607 if (sm_slave_request_security) { 2608 // request security if requested by app 2609 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2610 } else { 2611 // otherwise, wait for pairing request 2612 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2613 } 2614 } 2615 break; 2616 } else { 2617 // master 2618 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2619 } 2620 break; 2621 2622 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2623 con_handle = little_endian_read_16(packet, 3); 2624 sm_conn = sm_get_connection_for_handle(con_handle); 2625 if (!sm_conn) break; 2626 2627 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2628 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2629 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2630 break; 2631 } 2632 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2633 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2634 break; 2635 } 2636 2637 // assume that we don't have a LTK for ediv == 0 and random == null 2638 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2639 log_info("LTK Request: ediv & random are empty"); 2640 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2641 break; 2642 } 2643 2644 // store rand and ediv 2645 reverse_64(&packet[5], sm_conn->sm_local_rand); 2646 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2647 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2648 break; 2649 2650 default: 2651 break; 2652 } 2653 break; 2654 2655 case HCI_EVENT_ENCRYPTION_CHANGE: 2656 con_handle = little_endian_read_16(packet, 3); 2657 sm_conn = sm_get_connection_for_handle(con_handle); 2658 if (!sm_conn) break; 2659 2660 sm_conn->sm_connection_encrypted = packet[5]; 2661 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2662 sm_conn->sm_actual_encryption_key_size); 2663 log_info("event handler, state %u", sm_conn->sm_engine_state); 2664 if (!sm_conn->sm_connection_encrypted) break; 2665 // continue if part of initial pairing 2666 switch (sm_conn->sm_engine_state){ 2667 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2668 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2669 sm_done_for_handle(sm_conn->sm_handle); 2670 break; 2671 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2672 if (sm_conn->sm_role){ 2673 // slave 2674 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2675 } else { 2676 // master 2677 if (sm_key_distribution_all_received(sm_conn)){ 2678 // skip receiving keys as there are none 2679 sm_key_distribution_handle_all_received(sm_conn); 2680 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2681 } else { 2682 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2683 } 2684 } 2685 break; 2686 default: 2687 break; 2688 } 2689 break; 2690 2691 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2692 con_handle = little_endian_read_16(packet, 3); 2693 sm_conn = sm_get_connection_for_handle(con_handle); 2694 if (!sm_conn) break; 2695 2696 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2697 log_info("event handler, state %u", sm_conn->sm_engine_state); 2698 // continue if part of initial pairing 2699 switch (sm_conn->sm_engine_state){ 2700 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2701 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2702 sm_done_for_handle(sm_conn->sm_handle); 2703 break; 2704 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2705 if (sm_conn->sm_role){ 2706 // slave 2707 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2708 } else { 2709 // master 2710 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2711 } 2712 break; 2713 default: 2714 break; 2715 } 2716 break; 2717 2718 2719 case HCI_EVENT_DISCONNECTION_COMPLETE: 2720 con_handle = little_endian_read_16(packet, 3); 2721 sm_done_for_handle(con_handle); 2722 sm_conn = sm_get_connection_for_handle(con_handle); 2723 if (!sm_conn) break; 2724 2725 // delete stored bonding on disconnect with authentication failure in ph0 2726 if (sm_conn->sm_role == 0 2727 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2728 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2729 le_device_db_remove(sm_conn->sm_le_db_index); 2730 } 2731 2732 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2733 sm_conn->sm_handle = 0; 2734 break; 2735 2736 case HCI_EVENT_COMMAND_COMPLETE: 2737 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2738 sm_handle_encryption_result(&packet[6]); 2739 break; 2740 } 2741 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2742 sm_handle_random_result(&packet[6]); 2743 break; 2744 } 2745 break; 2746 default: 2747 break; 2748 } 2749 break; 2750 default: 2751 break; 2752 } 2753 2754 sm_run(); 2755 } 2756 2757 static inline int sm_calc_actual_encryption_key_size(int other){ 2758 if (other < sm_min_encryption_key_size) return 0; 2759 if (other < sm_max_encryption_key_size) return other; 2760 return sm_max_encryption_key_size; 2761 } 2762 2763 static int sm_passkey_used(stk_generation_method_t method){ 2764 switch (method){ 2765 case PK_RESP_INPUT: 2766 case PK_INIT_INPUT: 2767 case OK_BOTH_INPUT: 2768 return 1; 2769 default: 2770 return 0; 2771 } 2772 } 2773 2774 /** 2775 * @return ok 2776 */ 2777 static int sm_validate_stk_generation_method(void){ 2778 // check if STK generation method is acceptable by client 2779 switch (setup->sm_stk_generation_method){ 2780 case JUST_WORKS: 2781 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2782 case PK_RESP_INPUT: 2783 case PK_INIT_INPUT: 2784 case OK_BOTH_INPUT: 2785 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2786 case OOB: 2787 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2788 case NK_BOTH_INPUT: 2789 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2790 return 1; 2791 default: 2792 return 0; 2793 } 2794 } 2795 2796 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2797 2798 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2799 sm_run(); 2800 } 2801 2802 if (packet_type != SM_DATA_PACKET) return; 2803 2804 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2805 if (!sm_conn) return; 2806 2807 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2808 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2809 return; 2810 } 2811 2812 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2813 2814 int err; 2815 2816 switch (sm_conn->sm_engine_state){ 2817 2818 // a sm timeout requries a new physical connection 2819 case SM_GENERAL_TIMEOUT: 2820 return; 2821 2822 // Initiator 2823 case SM_INITIATOR_CONNECTED: 2824 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2825 sm_pdu_received_in_wrong_state(sm_conn); 2826 break; 2827 } 2828 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2829 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2830 break; 2831 } 2832 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2833 uint16_t ediv; 2834 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2835 if (ediv){ 2836 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2837 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2838 } else { 2839 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2840 } 2841 break; 2842 } 2843 // otherwise, store security request 2844 sm_conn->sm_security_request_received = 1; 2845 break; 2846 2847 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2848 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2849 sm_pdu_received_in_wrong_state(sm_conn); 2850 break; 2851 } 2852 // store pairing request 2853 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2854 err = sm_stk_generation_init(sm_conn); 2855 if (err){ 2856 setup->sm_pairing_failed_reason = err; 2857 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2858 break; 2859 } 2860 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2861 if (setup->sm_use_secure_connections){ 2862 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2863 if (setup->sm_stk_generation_method == JUST_WORKS){ 2864 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2865 sm_trigger_user_response(sm_conn); 2866 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2867 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2868 } 2869 } else { 2870 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2871 } 2872 break; 2873 } 2874 #endif 2875 // generate random number first, if we need to show passkey 2876 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2877 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2878 break; 2879 } 2880 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2881 sm_trigger_user_response(sm_conn); 2882 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2883 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2884 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2885 } 2886 break; 2887 2888 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2889 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2890 sm_pdu_received_in_wrong_state(sm_conn); 2891 break; 2892 } 2893 2894 // store s_confirm 2895 reverse_128(&packet[1], setup->sm_peer_confirm); 2896 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2897 break; 2898 2899 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2900 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2901 sm_pdu_received_in_wrong_state(sm_conn); 2902 break;; 2903 } 2904 2905 // received random value 2906 reverse_128(&packet[1], setup->sm_peer_random); 2907 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2908 break; 2909 2910 // Responder 2911 case SM_RESPONDER_IDLE: 2912 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2913 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2914 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2915 sm_pdu_received_in_wrong_state(sm_conn); 2916 break;; 2917 } 2918 2919 // store pairing request 2920 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2921 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2922 break; 2923 2924 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2925 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2926 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2927 sm_pdu_received_in_wrong_state(sm_conn); 2928 break; 2929 } 2930 2931 // store public key for DH Key calculation 2932 reverse_256(&packet[01], setup->sm_peer_qx); 2933 reverse_256(&packet[33], setup->sm_peer_qy); 2934 2935 #ifdef USE_MBEDTLS_FOR_ECDH 2936 // validate public key 2937 mbedtls_ecp_group grp; 2938 mbedtls_ecp_group_init( &grp ); 2939 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2940 2941 mbedtls_ecp_point Q; 2942 mbedtls_ecp_point_init( &Q ); 2943 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2944 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2945 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2946 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2947 if (err){ 2948 log_error("sm: peer public key invalid %x", err); 2949 // uses "unspecified reason", there is no "public key invalid" error code 2950 sm_pdu_received_in_wrong_state(sm_conn); 2951 break; 2952 } 2953 #endif 2954 if (sm_conn->sm_role){ 2955 // responder 2956 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2957 } else { 2958 // initiator 2959 // stk generation method 2960 // passkey entry: notify app to show passkey or to request passkey 2961 switch (setup->sm_stk_generation_method){ 2962 case JUST_WORKS: 2963 case NK_BOTH_INPUT: 2964 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2965 break; 2966 case PK_INIT_INPUT: 2967 case PK_RESP_INPUT: 2968 case OK_BOTH_INPUT: 2969 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2970 break; 2971 case OOB: 2972 // TODO: implement SC OOB 2973 break; 2974 } 2975 } 2976 break; 2977 2978 case SM_SC_W4_CONFIRMATION: 2979 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2980 sm_pdu_received_in_wrong_state(sm_conn); 2981 break; 2982 } 2983 // received confirm value 2984 reverse_128(&packet[1], setup->sm_peer_confirm); 2985 2986 if (sm_conn->sm_role){ 2987 // responder 2988 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2989 } else { 2990 // initiator 2991 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2992 } 2993 break; 2994 2995 case SM_SC_W4_PAIRING_RANDOM: 2996 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2997 sm_pdu_received_in_wrong_state(sm_conn); 2998 break; 2999 } 3000 3001 // received random value 3002 reverse_128(&packet[1], setup->sm_peer_nonce); 3003 3004 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3005 // only check for JUST WORK/NC in initiator role AND passkey entry 3006 int passkey_entry = sm_passkey_used(setup->sm_stk_generation_method); 3007 if (sm_conn->sm_role || passkey_entry) { 3008 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3009 } 3010 3011 sm_sc_state_after_receiving_random(sm_conn); 3012 break; 3013 3014 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3015 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3016 sm_pdu_received_in_wrong_state(sm_conn); 3017 break; 3018 } 3019 // store DHKey Check 3020 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3021 3022 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3023 break; 3024 #endif 3025 3026 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3027 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3028 sm_pdu_received_in_wrong_state(sm_conn); 3029 break; 3030 } 3031 3032 // received confirm value 3033 reverse_128(&packet[1], setup->sm_peer_confirm); 3034 3035 // notify client to hide shown passkey 3036 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3037 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3038 } 3039 3040 // handle user cancel pairing? 3041 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3042 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3043 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3044 break; 3045 } 3046 3047 // wait for user action? 3048 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3049 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3050 break; 3051 } 3052 3053 // calculate and send local_confirm 3054 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3055 break; 3056 3057 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3058 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3059 sm_pdu_received_in_wrong_state(sm_conn); 3060 break;; 3061 } 3062 3063 // received random value 3064 reverse_128(&packet[1], setup->sm_peer_random); 3065 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3066 break; 3067 3068 case SM_PH3_RECEIVE_KEYS: 3069 switch(packet[0]){ 3070 case SM_CODE_ENCRYPTION_INFORMATION: 3071 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3072 reverse_128(&packet[1], setup->sm_peer_ltk); 3073 break; 3074 3075 case SM_CODE_MASTER_IDENTIFICATION: 3076 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3077 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3078 reverse_64(&packet[3], setup->sm_peer_rand); 3079 break; 3080 3081 case SM_CODE_IDENTITY_INFORMATION: 3082 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3083 reverse_128(&packet[1], setup->sm_peer_irk); 3084 break; 3085 3086 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3087 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3088 setup->sm_peer_addr_type = packet[1]; 3089 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3090 break; 3091 3092 case SM_CODE_SIGNING_INFORMATION: 3093 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3094 reverse_128(&packet[1], setup->sm_peer_csrk); 3095 break; 3096 default: 3097 // Unexpected PDU 3098 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3099 break; 3100 } 3101 // done with key distribution? 3102 if (sm_key_distribution_all_received(sm_conn)){ 3103 3104 sm_key_distribution_handle_all_received(sm_conn); 3105 3106 if (sm_conn->sm_role){ 3107 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3108 sm_done_for_handle(sm_conn->sm_handle); 3109 } else { 3110 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3111 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3112 if (setup->sm_use_secure_connections){ 3113 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3114 } 3115 #endif 3116 } 3117 } 3118 break; 3119 default: 3120 // Unexpected PDU 3121 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3122 break; 3123 } 3124 3125 // try to send preparared packet 3126 sm_run(); 3127 } 3128 3129 // Security Manager Client API 3130 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3131 sm_get_oob_data = get_oob_data_callback; 3132 } 3133 3134 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3135 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3136 } 3137 3138 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3139 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3140 } 3141 3142 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3143 sm_min_encryption_key_size = min_size; 3144 sm_max_encryption_key_size = max_size; 3145 } 3146 3147 void sm_set_authentication_requirements(uint8_t auth_req){ 3148 sm_auth_req = auth_req; 3149 } 3150 3151 void sm_set_io_capabilities(io_capability_t io_capability){ 3152 sm_io_capabilities = io_capability; 3153 } 3154 3155 void sm_set_request_security(int enable){ 3156 sm_slave_request_security = enable; 3157 } 3158 3159 void sm_set_er(sm_key_t er){ 3160 memcpy(sm_persistent_er, er, 16); 3161 } 3162 3163 void sm_set_ir(sm_key_t ir){ 3164 memcpy(sm_persistent_ir, ir, 16); 3165 } 3166 3167 // Testing support only 3168 void sm_test_set_irk(sm_key_t irk){ 3169 memcpy(sm_persistent_irk, irk, 16); 3170 sm_persistent_irk_ready = 1; 3171 } 3172 3173 void sm_test_use_fixed_local_csrk(void){ 3174 test_use_fixed_local_csrk = 1; 3175 } 3176 3177 void sm_init(void){ 3178 // set some (BTstack default) ER and IR 3179 int i; 3180 sm_key_t er; 3181 sm_key_t ir; 3182 for (i=0;i<16;i++){ 3183 er[i] = 0x30 + i; 3184 ir[i] = 0x90 + i; 3185 } 3186 sm_set_er(er); 3187 sm_set_ir(ir); 3188 // defaults 3189 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3190 | SM_STK_GENERATION_METHOD_OOB 3191 | SM_STK_GENERATION_METHOD_PASSKEY 3192 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3193 3194 sm_max_encryption_key_size = 16; 3195 sm_min_encryption_key_size = 7; 3196 3197 sm_cmac_state = CMAC_IDLE; 3198 dkg_state = DKG_W4_WORKING; 3199 rau_state = RAU_W4_WORKING; 3200 sm_aes128_state = SM_AES128_IDLE; 3201 sm_address_resolution_test = -1; // no private address to resolve yet 3202 sm_address_resolution_ah_calculation_active = 0; 3203 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3204 sm_address_resolution_general_queue = NULL; 3205 3206 gap_random_adress_update_period = 15 * 60 * 1000L; 3207 3208 sm_active_connection = 0; 3209 3210 test_use_fixed_local_csrk = 0; 3211 3212 // register for HCI Events from HCI 3213 hci_event_callback_registration.callback = &sm_event_packet_handler; 3214 hci_add_event_handler(&hci_event_callback_registration); 3215 3216 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3217 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3218 3219 #ifdef USE_MBEDTLS_FOR_ECDH 3220 // TODO: calculate keypair using LE Random Number Generator 3221 // use test keypair from spec initially 3222 mbedtls_ecp_keypair_init(&le_keypair); 3223 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3224 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3225 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3226 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3227 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3228 // print keypair 3229 char buffer[100]; 3230 size_t len; 3231 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3232 log_info("d: %s", buffer); 3233 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3234 log_info("X: %s", buffer); 3235 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3236 log_info("Y: %s", buffer); 3237 #endif 3238 } 3239 3240 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3241 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3242 if (!hci_con) return NULL; 3243 return &hci_con->sm_connection; 3244 } 3245 3246 // @returns 0 if not encrypted, 7-16 otherwise 3247 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3248 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3249 if (!sm_conn) return 0; // wrong connection 3250 if (!sm_conn->sm_connection_encrypted) return 0; 3251 return sm_conn->sm_actual_encryption_key_size; 3252 } 3253 3254 int sm_authenticated(hci_con_handle_t con_handle){ 3255 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3256 if (!sm_conn) return 0; // wrong connection 3257 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3258 return sm_conn->sm_connection_authenticated; 3259 } 3260 3261 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3262 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3263 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3264 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3265 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3266 return sm_conn->sm_connection_authorization_state; 3267 } 3268 3269 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3270 switch (sm_conn->sm_engine_state){ 3271 case SM_GENERAL_IDLE: 3272 case SM_RESPONDER_IDLE: 3273 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3274 sm_run(); 3275 break; 3276 default: 3277 break; 3278 } 3279 } 3280 3281 /** 3282 * @brief Trigger Security Request 3283 */ 3284 void sm_send_security_request(hci_con_handle_t con_handle){ 3285 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3286 if (!sm_conn) return; 3287 sm_send_security_request_for_connection(sm_conn); 3288 } 3289 3290 // request pairing 3291 void sm_request_pairing(hci_con_handle_t con_handle){ 3292 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3293 if (!sm_conn) return; // wrong connection 3294 3295 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3296 if (sm_conn->sm_role){ 3297 sm_send_security_request_for_connection(sm_conn); 3298 } else { 3299 // used as a trigger to start central/master/initiator security procedures 3300 uint16_t ediv; 3301 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3302 switch (sm_conn->sm_irk_lookup_state){ 3303 case IRK_LOOKUP_FAILED: 3304 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3305 break; 3306 case IRK_LOOKUP_SUCCEEDED: 3307 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3308 if (ediv){ 3309 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3310 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3311 } else { 3312 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3313 } 3314 break; 3315 default: 3316 sm_conn->sm_bonding_requested = 1; 3317 break; 3318 } 3319 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3320 sm_conn->sm_bonding_requested = 1; 3321 } 3322 } 3323 sm_run(); 3324 } 3325 3326 // called by client app on authorization request 3327 void sm_authorization_decline(hci_con_handle_t con_handle){ 3328 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3329 if (!sm_conn) return; // wrong connection 3330 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3331 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3332 } 3333 3334 void sm_authorization_grant(hci_con_handle_t con_handle){ 3335 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3336 if (!sm_conn) return; // wrong connection 3337 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3338 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3339 } 3340 3341 // GAP Bonding API 3342 3343 void sm_bonding_decline(hci_con_handle_t con_handle){ 3344 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3345 if (!sm_conn) return; // wrong connection 3346 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3347 3348 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3349 switch (setup->sm_stk_generation_method){ 3350 case PK_RESP_INPUT: 3351 case PK_INIT_INPUT: 3352 case OK_BOTH_INPUT: 3353 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3354 break; 3355 case NK_BOTH_INPUT: 3356 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3357 break; 3358 case JUST_WORKS: 3359 case OOB: 3360 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3361 break; 3362 } 3363 } 3364 sm_run(); 3365 } 3366 3367 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3368 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3369 if (!sm_conn) return; // wrong connection 3370 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3371 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3372 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3373 3374 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3375 if (setup->sm_use_secure_connections){ 3376 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3377 } 3378 #endif 3379 } 3380 3381 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3382 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3383 if (sm_conn->sm_role){ 3384 // responder 3385 sm_sc_prepare_dhkey_check(sm_conn); 3386 } else { 3387 // initiator 3388 // TODO handle intiator role 3389 } 3390 } 3391 #endif 3392 3393 sm_run(); 3394 } 3395 3396 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3397 // for now, it's the same 3398 sm_just_works_confirm(con_handle); 3399 } 3400 3401 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3402 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3403 if (!sm_conn) return; // wrong connection 3404 sm_reset_tk(); 3405 big_endian_store_32(setup->sm_tk, 12, passkey); 3406 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3407 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3408 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3409 } 3410 sm_run(); 3411 } 3412 3413 /** 3414 * @brief Identify device in LE Device DB 3415 * @param handle 3416 * @returns index from le_device_db or -1 if not found/identified 3417 */ 3418 int sm_le_device_index(hci_con_handle_t con_handle ){ 3419 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3420 if (!sm_conn) return -1; 3421 return sm_conn->sm_le_db_index; 3422 } 3423 3424 // GAP LE API 3425 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3426 gap_random_address_update_stop(); 3427 gap_random_adress_type = random_address_type; 3428 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3429 gap_random_address_update_start(); 3430 gap_random_address_trigger(); 3431 } 3432 3433 gap_random_address_type_t gap_random_address_get_mode(void){ 3434 return gap_random_adress_type; 3435 } 3436 3437 void gap_random_address_set_update_period(int period_ms){ 3438 gap_random_adress_update_period = period_ms; 3439 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3440 gap_random_address_update_stop(); 3441 gap_random_address_update_start(); 3442 } 3443 3444 void gap_random_address_set(bd_addr_t addr){ 3445 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3446 memcpy(sm_random_address, addr, 6); 3447 rau_state = RAU_SET_ADDRESS; 3448 sm_run(); 3449 } 3450 3451 /* 3452 * @brief Set Advertisement Paramters 3453 * @param adv_int_min 3454 * @param adv_int_max 3455 * @param adv_type 3456 * @param direct_address_type 3457 * @param direct_address 3458 * @param channel_map 3459 * @param filter_policy 3460 * 3461 * @note own_address_type is used from gap_random_address_set_mode 3462 */ 3463 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3464 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3465 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3466 direct_address_typ, direct_address, channel_map, filter_policy); 3467 } 3468 3469