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 typedef enum { 145 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 146 } sm_state_var_t; 147 148 // 149 // GLOBAL DATA 150 // 151 152 static uint8_t test_use_fixed_local_csrk; 153 154 // configuration 155 static uint8_t sm_accepted_stk_generation_methods; 156 static uint8_t sm_max_encryption_key_size; 157 static uint8_t sm_min_encryption_key_size; 158 static uint8_t sm_auth_req = 0; 159 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 160 static uint8_t sm_slave_request_security; 161 162 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 163 static sm_key_t sm_persistent_er; 164 static sm_key_t sm_persistent_ir; 165 166 // derived from sm_persistent_ir 167 static sm_key_t sm_persistent_dhk; 168 static sm_key_t sm_persistent_irk; 169 static uint8_t sm_persistent_irk_ready = 0; // used for testing 170 static derived_key_generation_t dkg_state; 171 172 // derived from sm_persistent_er 173 // .. 174 175 // random address update 176 static random_address_update_t rau_state; 177 static bd_addr_t sm_random_address; 178 179 // CMAC Calculation: General 180 static cmac_state_t sm_cmac_state; 181 static uint16_t sm_cmac_message_len; 182 static sm_key_t sm_cmac_k; 183 static sm_key_t sm_cmac_x; 184 static sm_key_t sm_cmac_m_last; 185 static uint8_t sm_cmac_block_current; 186 static uint8_t sm_cmac_block_count; 187 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 188 static void (*sm_cmac_done_handler)(uint8_t * hash); 189 190 // CMAC for ATT Signed Writes 191 static uint8_t sm_cmac_header[3]; 192 static const uint8_t * sm_cmac_message; 193 static uint8_t sm_cmac_sign_counter[4]; 194 195 // CMAC for Secure Connection functions 196 #ifdef ENABLE_LE_SECURE_CONNECTIONS 197 static sm_connection_t * sm_cmac_connection; 198 static uint8_t sm_cmac_sc_buffer[80]; 199 #endif 200 201 // resolvable private address lookup / CSRK calculation 202 static int sm_address_resolution_test; 203 static int sm_address_resolution_ah_calculation_active; 204 static uint8_t sm_address_resolution_addr_type; 205 static bd_addr_t sm_address_resolution_address; 206 static void * sm_address_resolution_context; 207 static address_resolution_mode_t sm_address_resolution_mode; 208 static btstack_linked_list_t sm_address_resolution_general_queue; 209 210 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 211 static sm_aes128_state_t sm_aes128_state; 212 static void * sm_aes128_context; 213 214 // random engine. store context (ususally sm_connection_t) 215 static void * sm_random_context; 216 217 // to receive hci events 218 static btstack_packet_callback_registration_t hci_event_callback_registration; 219 220 /* to dispatch sm event */ 221 static btstack_linked_list_t sm_event_handlers; 222 223 // Software ECDH implementation provided by mbedtls 224 #ifdef USE_MBEDTLS_FOR_ECDH 225 mbedtls_ecp_keypair le_keypair; 226 #endif 227 228 // 229 // Volume 3, Part H, Chapter 24 230 // "Security shall be initiated by the Security Manager in the device in the master role. 231 // The device in the slave role shall be the responding device." 232 // -> master := initiator, slave := responder 233 // 234 235 // data needed for security setup 236 typedef struct sm_setup_context { 237 238 btstack_timer_source_t sm_timeout; 239 240 // used in all phases 241 uint8_t sm_pairing_failed_reason; 242 243 // user response, (Phase 1 and/or 2) 244 uint8_t sm_user_response; 245 246 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 247 int sm_key_distribution_send_set; 248 int sm_key_distribution_received_set; 249 250 // Phase 2 (Pairing over SMP) 251 stk_generation_method_t sm_stk_generation_method; 252 sm_key_t sm_tk; 253 uint8_t sm_use_secure_connections; 254 255 sm_key_t sm_c1_t3_value; // c1 calculation 256 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 257 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 258 sm_key_t sm_local_random; 259 sm_key_t sm_local_confirm; 260 sm_key_t sm_peer_random; 261 sm_key_t sm_peer_confirm; 262 uint8_t sm_m_addr_type; // address and type can be removed 263 uint8_t sm_s_addr_type; // '' 264 bd_addr_t sm_m_address; // '' 265 bd_addr_t sm_s_address; // '' 266 sm_key_t sm_ltk; 267 268 #ifdef ENABLE_LE_SECURE_CONNECTIONS 269 uint8_t sm_peer_qx[32]; 270 uint8_t sm_peer_qy[32]; 271 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 272 sm_key_t sm_local_nonce; // might be combined with sm_local_random 273 sm_key_t sm_peer_dhkey_check; 274 sm_key_t sm_local_dhkey_check; 275 sm_key_t sm_ra; 276 sm_key_t sm_rb; 277 sm_key_t sm_t; // used for f5 278 sm_key_t sm_mackey; 279 uint8_t sm_passkey_bit; 280 uint8_t sm_state_vars; 281 #endif 282 283 // Phase 3 284 285 // key distribution, we generate 286 uint16_t sm_local_y; 287 uint16_t sm_local_div; 288 uint16_t sm_local_ediv; 289 uint8_t sm_local_rand[8]; 290 sm_key_t sm_local_ltk; 291 sm_key_t sm_local_csrk; 292 sm_key_t sm_local_irk; 293 // sm_local_address/addr_type not needed 294 295 // key distribution, received from peer 296 uint16_t sm_peer_y; 297 uint16_t sm_peer_div; 298 uint16_t sm_peer_ediv; 299 uint8_t sm_peer_rand[8]; 300 sm_key_t sm_peer_ltk; 301 sm_key_t sm_peer_irk; 302 sm_key_t sm_peer_csrk; 303 uint8_t sm_peer_addr_type; 304 bd_addr_t sm_peer_address; 305 306 } sm_setup_context_t; 307 308 // 309 static sm_setup_context_t the_setup; 310 static sm_setup_context_t * setup = &the_setup; 311 312 // active connection - the one for which the_setup is used for 313 static uint16_t sm_active_connection = 0; 314 315 // @returns 1 if oob data is available 316 // stores oob data in provided 16 byte buffer if not null 317 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 318 319 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 320 static btstack_packet_handler_t sm_client_packet_handler = NULL; 321 322 // horizontal: initiator capabilities 323 // vertial: responder capabilities 324 static const stk_generation_method_t stk_generation_method [5] [5] = { 325 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 326 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 327 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 328 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 329 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 330 }; 331 332 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 333 #ifdef ENABLE_LE_SECURE_CONNECTIONS 334 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 335 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 336 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 337 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 338 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 339 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 340 }; 341 #endif 342 343 static void sm_run(void); 344 static void sm_done_for_handle(hci_con_handle_t con_handle); 345 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 346 static inline int sm_calc_actual_encryption_key_size(int other); 347 static int sm_validate_stk_generation_method(void); 348 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 349 350 static void log_info_hex16(const char * name, uint16_t value){ 351 log_info("%-6s 0x%04x", name, value); 352 } 353 354 // @returns 1 if all bytes are 0 355 static int sm_is_null_random(uint8_t random[8]){ 356 int i; 357 for (i=0; i < 8 ; i++){ 358 if (random[i]) return 0; 359 } 360 return 1; 361 } 362 363 // Key utils 364 static void sm_reset_tk(void){ 365 int i; 366 for (i=0;i<16;i++){ 367 setup->sm_tk[i] = 0; 368 } 369 } 370 371 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 372 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 373 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 374 int i; 375 for (i = max_encryption_size ; i < 16 ; i++){ 376 key[15-i] = 0; 377 } 378 } 379 380 // SMP Timeout implementation 381 382 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 383 // the Security Manager Timer shall be reset and started. 384 // 385 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 386 // 387 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 388 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 389 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 390 // established. 391 392 static void sm_timeout_handler(btstack_timer_source_t * timer){ 393 log_info("SM timeout"); 394 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 395 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 396 sm_done_for_handle(sm_conn->sm_handle); 397 398 // trigger handling of next ready connection 399 sm_run(); 400 } 401 static void sm_timeout_start(sm_connection_t * sm_conn){ 402 btstack_run_loop_remove_timer(&setup->sm_timeout); 403 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 404 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 405 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 406 btstack_run_loop_add_timer(&setup->sm_timeout); 407 } 408 static void sm_timeout_stop(void){ 409 btstack_run_loop_remove_timer(&setup->sm_timeout); 410 } 411 static void sm_timeout_reset(sm_connection_t * sm_conn){ 412 sm_timeout_stop(); 413 sm_timeout_start(sm_conn); 414 } 415 416 // end of sm timeout 417 418 // GAP Random Address updates 419 static gap_random_address_type_t gap_random_adress_type; 420 static btstack_timer_source_t gap_random_address_update_timer; 421 static uint32_t gap_random_adress_update_period; 422 423 static void gap_random_address_trigger(void){ 424 if (rau_state != RAU_IDLE) return; 425 log_info("gap_random_address_trigger"); 426 rau_state = RAU_GET_RANDOM; 427 sm_run(); 428 } 429 430 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 431 log_info("GAP Random Address Update due"); 432 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 433 btstack_run_loop_add_timer(&gap_random_address_update_timer); 434 gap_random_address_trigger(); 435 } 436 437 static void gap_random_address_update_start(void){ 438 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 439 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 440 btstack_run_loop_add_timer(&gap_random_address_update_timer); 441 } 442 443 static void gap_random_address_update_stop(void){ 444 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 445 } 446 447 448 static void sm_random_start(void * context){ 449 sm_random_context = context; 450 hci_send_cmd(&hci_le_rand); 451 } 452 453 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 454 // context is made availabe to aes128 result handler by this 455 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 456 sm_aes128_state = SM_AES128_ACTIVE; 457 sm_key_t key_flipped, plaintext_flipped; 458 reverse_128(key, key_flipped); 459 reverse_128(plaintext, plaintext_flipped); 460 sm_aes128_context = context; 461 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 462 } 463 464 // ah(k,r) helper 465 // r = padding || r 466 // r - 24 bit value 467 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 468 // r'= padding || r 469 memset(r_prime, 0, 16); 470 memcpy(&r_prime[13], r, 3); 471 } 472 473 // d1 helper 474 // d' = padding || r || d 475 // d,r - 16 bit values 476 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 477 // d'= padding || r || d 478 memset(d1_prime, 0, 16); 479 big_endian_store_16(d1_prime, 12, r); 480 big_endian_store_16(d1_prime, 14, d); 481 } 482 483 // dm helper 484 // r’ = padding || r 485 // r - 64 bit value 486 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 487 memset(r_prime, 0, 16); 488 memcpy(&r_prime[8], r, 8); 489 } 490 491 // calculate arguments for first AES128 operation in C1 function 492 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){ 493 494 // p1 = pres || preq || rat’ || iat’ 495 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 496 // cant octet of pres becomes the most significant octet of p1. 497 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 498 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 499 // p1 is 0x05000800000302070710000001010001." 500 501 sm_key_t p1; 502 reverse_56(pres, &p1[0]); 503 reverse_56(preq, &p1[7]); 504 p1[14] = rat; 505 p1[15] = iat; 506 log_info_key("p1", p1); 507 log_info_key("r", r); 508 509 // t1 = r xor p1 510 int i; 511 for (i=0;i<16;i++){ 512 t1[i] = r[i] ^ p1[i]; 513 } 514 log_info_key("t1", t1); 515 } 516 517 // calculate arguments for second AES128 operation in C1 function 518 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 519 // p2 = padding || ia || ra 520 // "The least significant octet of ra becomes the least significant octet of p2 and 521 // the most significant octet of padding becomes the most significant octet of p2. 522 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 523 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 524 525 sm_key_t p2; 526 memset(p2, 0, 16); 527 memcpy(&p2[4], ia, 6); 528 memcpy(&p2[10], ra, 6); 529 log_info_key("p2", p2); 530 531 // c1 = e(k, t2_xor_p2) 532 int i; 533 for (i=0;i<16;i++){ 534 t3[i] = t2[i] ^ p2[i]; 535 } 536 log_info_key("t3", t3); 537 } 538 539 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 540 log_info_key("r1", r1); 541 log_info_key("r2", r2); 542 memcpy(&r_prime[8], &r2[8], 8); 543 memcpy(&r_prime[0], &r1[8], 8); 544 } 545 546 #ifdef ENABLE_LE_SECURE_CONNECTIONS 547 // Software implementations of crypto toolbox for LE Secure Connection 548 // TODO: replace with code to use AES Engine of HCI Controller 549 typedef uint8_t sm_key24_t[3]; 550 typedef uint8_t sm_key56_t[7]; 551 typedef uint8_t sm_key256_t[32]; 552 553 #if 0 554 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 555 uint32_t rk[RKLENGTH(KEYBITS)]; 556 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 557 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 558 } 559 560 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 561 memcpy(k1, k0, 16); 562 sm_shift_left_by_one_bit_inplace(16, k1); 563 if (k0[0] & 0x80){ 564 k1[15] ^= 0x87; 565 } 566 memcpy(k2, k1, 16); 567 sm_shift_left_by_one_bit_inplace(16, k2); 568 if (k1[0] & 0x80){ 569 k2[15] ^= 0x87; 570 } 571 } 572 573 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 574 sm_key_t k0, k1, k2, zero; 575 memset(zero, 0, 16); 576 577 aes128_calc_cyphertext(key, zero, k0); 578 calc_subkeys(k0, k1, k2); 579 580 int cmac_block_count = (cmac_message_len + 15) / 16; 581 582 // step 3: .. 583 if (cmac_block_count==0){ 584 cmac_block_count = 1; 585 } 586 587 // step 4: set m_last 588 sm_key_t cmac_m_last; 589 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 590 int i; 591 if (sm_cmac_last_block_complete){ 592 for (i=0;i<16;i++){ 593 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 594 } 595 } else { 596 int valid_octets_in_last_block = cmac_message_len & 0x0f; 597 for (i=0;i<16;i++){ 598 if (i < valid_octets_in_last_block){ 599 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 600 continue; 601 } 602 if (i == valid_octets_in_last_block){ 603 cmac_m_last[i] = 0x80 ^ k2[i]; 604 continue; 605 } 606 cmac_m_last[i] = k2[i]; 607 } 608 } 609 610 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 611 // LOG_KEY(cmac_m_last); 612 613 // Step 5 614 sm_key_t cmac_x; 615 memset(cmac_x, 0, 16); 616 617 // Step 6 618 sm_key_t sm_cmac_y; 619 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 620 for (i=0;i<16;i++){ 621 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 622 } 623 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 624 } 625 for (i=0;i<16;i++){ 626 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 627 } 628 629 // Step 7 630 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 631 } 632 #endif 633 634 #if 0 635 // 636 // Link Key Conversion Function h6 637 // 638 // h6(W, keyID) = AES-CMACW(keyID) 639 // - W is 128 bits 640 // - keyID is 32 bits 641 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 642 uint8_t key_id_buffer[4]; 643 big_endian_store_32(key_id_buffer, 0, key_id); 644 aes_cmac(res, w, key_id_buffer, 4); 645 } 646 #endif 647 #endif 648 649 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){ 650 event[0] = type; 651 event[1] = event_size - 2; 652 little_endian_store_16(event, 2, con_handle); 653 event[4] = addr_type; 654 reverse_bd_addr(address, &event[5]); 655 } 656 657 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 658 if (sm_client_packet_handler) { 659 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 660 } 661 // dispatch to all event handlers 662 btstack_linked_list_iterator_t it; 663 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 664 while (btstack_linked_list_iterator_has_next(&it)){ 665 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 666 entry->callback(packet_type, 0, packet, size); 667 } 668 } 669 670 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 671 uint8_t event[11]; 672 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 673 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 674 } 675 676 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){ 677 uint8_t event[15]; 678 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 679 little_endian_store_32(event, 11, passkey); 680 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 681 } 682 683 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){ 684 uint8_t event[13]; 685 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 686 little_endian_store_16(event, 11, index); 687 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 688 } 689 690 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){ 691 692 uint8_t event[18]; 693 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 694 event[11] = result; 695 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 696 } 697 698 // decide on stk generation based on 699 // - pairing request 700 // - io capabilities 701 // - OOB data availability 702 static void sm_setup_tk(void){ 703 704 // default: just works 705 setup->sm_stk_generation_method = JUST_WORKS; 706 707 #ifdef ENABLE_LE_SECURE_CONNECTIONS 708 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 709 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 710 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 711 memset(setup->sm_ra, 0, 16); 712 memset(setup->sm_rb, 0, 16); 713 #else 714 setup->sm_use_secure_connections = 0; 715 #endif 716 717 // If both devices have not set the MITM option in the Authentication Requirements 718 // Flags, then the IO capabilities shall be ignored and the Just Works association 719 // model shall be used. 720 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 721 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 722 log_info("SM: MITM not required by both -> JUST WORKS"); 723 return; 724 } 725 726 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 727 728 // If both devices have out of band authentication data, then the Authentication 729 // Requirements Flags shall be ignored when selecting the pairing method and the 730 // Out of Band pairing method shall be used. 731 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 732 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 733 log_info("SM: have OOB data"); 734 log_info_key("OOB", setup->sm_tk); 735 setup->sm_stk_generation_method = OOB; 736 return; 737 } 738 739 // Reset TK as it has been setup in sm_init_setup 740 sm_reset_tk(); 741 742 // Also use just works if unknown io capabilites 743 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)){ 744 return; 745 } 746 747 // Otherwise the IO capabilities of the devices shall be used to determine the 748 // pairing method as defined in Table 2.4. 749 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 750 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 751 752 #ifdef ENABLE_LE_SECURE_CONNECTIONS 753 // table not define by default 754 if (setup->sm_use_secure_connections){ 755 generation_method = stk_generation_method_with_secure_connection; 756 } 757 #endif 758 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)]; 759 760 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 761 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); 762 } 763 764 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 765 int flags = 0; 766 if (key_set & SM_KEYDIST_ENC_KEY){ 767 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 768 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 769 } 770 if (key_set & SM_KEYDIST_ID_KEY){ 771 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 772 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 773 } 774 if (key_set & SM_KEYDIST_SIGN){ 775 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 776 } 777 return flags; 778 } 779 780 static void sm_setup_key_distribution(uint8_t key_set){ 781 setup->sm_key_distribution_received_set = 0; 782 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 783 } 784 785 // CSRK Key Lookup 786 787 788 static int sm_address_resolution_idle(void){ 789 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 790 } 791 792 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){ 793 memcpy(sm_address_resolution_address, addr, 6); 794 sm_address_resolution_addr_type = addr_type; 795 sm_address_resolution_test = 0; 796 sm_address_resolution_mode = mode; 797 sm_address_resolution_context = context; 798 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 799 } 800 801 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 802 // check if already in list 803 btstack_linked_list_iterator_t it; 804 sm_lookup_entry_t * entry; 805 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 806 while(btstack_linked_list_iterator_has_next(&it)){ 807 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 808 if (entry->address_type != address_type) continue; 809 if (memcmp(entry->address, address, 6)) continue; 810 // already in list 811 return BTSTACK_BUSY; 812 } 813 entry = btstack_memory_sm_lookup_entry_get(); 814 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 815 entry->address_type = (bd_addr_type_t) address_type; 816 memcpy(entry->address, address, 6); 817 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 818 sm_run(); 819 return 0; 820 } 821 822 // CMAC Implementation using AES128 engine 823 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 824 int i; 825 int carry = 0; 826 for (i=len-1; i >= 0 ; i--){ 827 int new_carry = data[i] >> 7; 828 data[i] = data[i] << 1 | carry; 829 carry = new_carry; 830 } 831 } 832 833 // 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 834 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 835 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 836 } 837 static inline void dkg_next_state(void){ 838 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 839 } 840 static inline void rau_next_state(void){ 841 rau_state = (random_address_update_t) (((int)rau_state) + 1); 842 } 843 844 // CMAC calculation using AES Engine 845 846 static inline void sm_cmac_next_state(void){ 847 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 848 } 849 850 static int sm_cmac_last_block_complete(void){ 851 if (sm_cmac_message_len == 0) return 0; 852 return (sm_cmac_message_len & 0x0f) == 0; 853 } 854 855 static inline uint8_t sm_cmac_message_get_byte(uint16_t offset){ 856 if (offset >= sm_cmac_message_len) { 857 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 858 return 0; 859 } 860 861 offset = sm_cmac_message_len - 1 - offset; 862 863 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 864 if (offset < 3){ 865 return sm_cmac_header[offset]; 866 } 867 int actual_message_len_incl_header = sm_cmac_message_len - 4; 868 if (offset < actual_message_len_incl_header){ 869 return sm_cmac_message[offset - 3]; 870 } 871 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 872 } 873 874 // generic cmac calculation 875 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])){ 876 // Generalized CMAC 877 memcpy(sm_cmac_k, key, 16); 878 memset(sm_cmac_x, 0, 16); 879 sm_cmac_block_current = 0; 880 sm_cmac_message_len = message_len; 881 sm_cmac_done_handler = done_callback; 882 sm_cmac_get_byte = get_byte_callback; 883 884 // step 2: n := ceil(len/const_Bsize); 885 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 886 887 // step 3: .. 888 if (sm_cmac_block_count==0){ 889 sm_cmac_block_count = 1; 890 } 891 log_info("sm_cmac_connection %p", sm_cmac_connection); 892 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 893 894 // first, we need to compute l for k1, k2, and m_last 895 sm_cmac_state = CMAC_CALC_SUBKEYS; 896 897 // let's go 898 sm_run(); 899 } 900 901 // cmac for ATT Message signing 902 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)){ 903 // ATT Message Signing 904 sm_cmac_header[0] = opcode; 905 little_endian_store_16(sm_cmac_header, 1, con_handle); 906 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 907 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 908 sm_cmac_message = message; 909 sm_cmac_general_start(k, total_message_len, &sm_cmac_message_get_byte, done_handler); 910 } 911 912 int sm_cmac_ready(void){ 913 return sm_cmac_state == CMAC_IDLE; 914 } 915 916 static void sm_cmac_handle_aes_engine_ready(void){ 917 switch (sm_cmac_state){ 918 case CMAC_CALC_SUBKEYS: { 919 sm_key_t const_zero; 920 memset(const_zero, 0, 16); 921 sm_cmac_next_state(); 922 sm_aes128_start(sm_cmac_k, const_zero, NULL); 923 break; 924 } 925 case CMAC_CALC_MI: { 926 int j; 927 sm_key_t y; 928 for (j=0;j<16;j++){ 929 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 930 } 931 sm_cmac_block_current++; 932 sm_cmac_next_state(); 933 sm_aes128_start(sm_cmac_k, y, NULL); 934 break; 935 } 936 case CMAC_CALC_MLAST: { 937 int i; 938 sm_key_t y; 939 for (i=0;i<16;i++){ 940 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 941 } 942 log_info_key("Y", y); 943 sm_cmac_block_current++; 944 sm_cmac_next_state(); 945 sm_aes128_start(sm_cmac_k, y, NULL); 946 break; 947 } 948 default: 949 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 950 break; 951 } 952 } 953 954 static void sm_cmac_handle_encryption_result(sm_key_t data){ 955 switch (sm_cmac_state){ 956 case CMAC_W4_SUBKEYS: { 957 sm_key_t k1; 958 memcpy(k1, data, 16); 959 sm_shift_left_by_one_bit_inplace(16, k1); 960 if (data[0] & 0x80){ 961 k1[15] ^= 0x87; 962 } 963 sm_key_t k2; 964 memcpy(k2, k1, 16); 965 sm_shift_left_by_one_bit_inplace(16, k2); 966 if (k1[0] & 0x80){ 967 k2[15] ^= 0x87; 968 } 969 970 log_info_key("k", sm_cmac_k); 971 log_info_key("k1", k1); 972 log_info_key("k2", k2); 973 974 // step 4: set m_last 975 int i; 976 if (sm_cmac_last_block_complete()){ 977 for (i=0;i<16;i++){ 978 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 979 } 980 } else { 981 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 982 for (i=0;i<16;i++){ 983 if (i < valid_octets_in_last_block){ 984 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 985 continue; 986 } 987 if (i == valid_octets_in_last_block){ 988 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 989 continue; 990 } 991 sm_cmac_m_last[i] = k2[i]; 992 } 993 } 994 995 // next 996 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 997 break; 998 } 999 case CMAC_W4_MI: 1000 memcpy(sm_cmac_x, data, 16); 1001 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1002 break; 1003 case CMAC_W4_MLAST: 1004 // done 1005 log_info("Setting CMAC Engine to IDLE"); 1006 sm_cmac_state = CMAC_IDLE; 1007 log_info_key("CMAC", data); 1008 sm_cmac_done_handler(data); 1009 break; 1010 default: 1011 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1012 break; 1013 } 1014 } 1015 1016 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1017 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1018 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1019 switch (setup->sm_stk_generation_method){ 1020 case PK_RESP_INPUT: 1021 if (sm_conn->sm_role){ 1022 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1023 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1024 } else { 1025 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)); 1026 } 1027 break; 1028 case PK_INIT_INPUT: 1029 if (sm_conn->sm_role){ 1030 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)); 1031 } else { 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 } 1035 break; 1036 case OK_BOTH_INPUT: 1037 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1038 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1039 break; 1040 case NK_BOTH_INPUT: 1041 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1042 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)); 1043 break; 1044 case JUST_WORKS: 1045 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1046 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1047 break; 1048 case OOB: 1049 // client already provided OOB data, let's skip notification. 1050 break; 1051 } 1052 } 1053 1054 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1055 int recv_flags; 1056 if (sm_conn->sm_role){ 1057 // slave / responder 1058 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1059 } else { 1060 // master / initiator 1061 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1062 } 1063 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1064 return recv_flags == setup->sm_key_distribution_received_set; 1065 } 1066 1067 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1068 if (sm_active_connection == con_handle){ 1069 sm_timeout_stop(); 1070 sm_active_connection = 0; 1071 log_info("sm: connection 0x%x released setup context", con_handle); 1072 } 1073 } 1074 1075 static int sm_key_distribution_flags_for_auth_req(void){ 1076 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1077 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1078 // encryption information only if bonding requested 1079 flags |= SM_KEYDIST_ENC_KEY; 1080 } 1081 return flags; 1082 } 1083 1084 static void sm_init_setup(sm_connection_t * sm_conn){ 1085 1086 // fill in sm setup 1087 setup->sm_state_vars = 0; 1088 sm_reset_tk(); 1089 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1090 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1091 1092 // query client for OOB data 1093 int have_oob_data = 0; 1094 if (sm_get_oob_data) { 1095 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1096 } 1097 1098 sm_pairing_packet_t * local_packet; 1099 if (sm_conn->sm_role){ 1100 // slave 1101 local_packet = &setup->sm_s_pres; 1102 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1103 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1104 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1105 } else { 1106 // master 1107 local_packet = &setup->sm_m_preq; 1108 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1109 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1110 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1111 1112 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1113 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1114 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1115 } 1116 1117 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1118 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1119 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1120 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1121 } 1122 1123 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1124 1125 sm_pairing_packet_t * remote_packet; 1126 int remote_key_request; 1127 if (sm_conn->sm_role){ 1128 // slave / responder 1129 remote_packet = &setup->sm_m_preq; 1130 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1131 } else { 1132 // master / initiator 1133 remote_packet = &setup->sm_s_pres; 1134 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1135 } 1136 1137 // check key size 1138 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1139 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1140 1141 // decide on STK generation method 1142 sm_setup_tk(); 1143 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1144 1145 // check if STK generation method is acceptable by client 1146 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1147 1148 // identical to responder 1149 sm_setup_key_distribution(remote_key_request); 1150 1151 // JUST WORKS doens't provide authentication 1152 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1153 1154 return 0; 1155 } 1156 1157 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1158 1159 // cache and reset context 1160 int matched_device_id = sm_address_resolution_test; 1161 address_resolution_mode_t mode = sm_address_resolution_mode; 1162 void * context = sm_address_resolution_context; 1163 1164 // reset context 1165 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1166 sm_address_resolution_context = NULL; 1167 sm_address_resolution_test = -1; 1168 hci_con_handle_t con_handle = 0; 1169 1170 sm_connection_t * sm_connection; 1171 uint16_t ediv; 1172 switch (mode){ 1173 case ADDRESS_RESOLUTION_GENERAL: 1174 break; 1175 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1176 sm_connection = (sm_connection_t *) context; 1177 con_handle = sm_connection->sm_handle; 1178 switch (event){ 1179 case ADDRESS_RESOLUTION_SUCEEDED: 1180 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1181 sm_connection->sm_le_db_index = matched_device_id; 1182 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1183 if (sm_connection->sm_role) break; 1184 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1185 sm_connection->sm_security_request_received = 0; 1186 sm_connection->sm_bonding_requested = 0; 1187 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1188 if (ediv){ 1189 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1190 } else { 1191 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1192 } 1193 break; 1194 case ADDRESS_RESOLUTION_FAILED: 1195 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1196 if (sm_connection->sm_role) break; 1197 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1198 sm_connection->sm_security_request_received = 0; 1199 sm_connection->sm_bonding_requested = 0; 1200 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1201 break; 1202 } 1203 break; 1204 default: 1205 break; 1206 } 1207 1208 switch (event){ 1209 case ADDRESS_RESOLUTION_SUCEEDED: 1210 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1211 break; 1212 case ADDRESS_RESOLUTION_FAILED: 1213 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1214 break; 1215 } 1216 } 1217 1218 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1219 1220 int le_db_index = -1; 1221 1222 // lookup device based on IRK 1223 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1224 int i; 1225 for (i=0; i < le_device_db_count(); i++){ 1226 sm_key_t irk; 1227 bd_addr_t address; 1228 int address_type; 1229 le_device_db_info(i, &address_type, address, irk); 1230 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1231 log_info("sm: device found for IRK, updating"); 1232 le_db_index = i; 1233 break; 1234 } 1235 } 1236 } 1237 1238 // if not found, lookup via public address if possible 1239 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1240 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1241 int i; 1242 for (i=0; i < le_device_db_count(); i++){ 1243 bd_addr_t address; 1244 int address_type; 1245 le_device_db_info(i, &address_type, address, NULL); 1246 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1247 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1248 log_info("sm: device found for public address, updating"); 1249 le_db_index = i; 1250 break; 1251 } 1252 } 1253 } 1254 1255 // if not found, add to db 1256 if (le_db_index < 0) { 1257 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1258 } 1259 1260 if (le_db_index >= 0){ 1261 le_device_db_local_counter_set(le_db_index, 0); 1262 1263 // store local CSRK 1264 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1265 log_info("sm: store local CSRK"); 1266 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1267 le_device_db_local_counter_set(le_db_index, 0); 1268 } 1269 1270 // store remote CSRK 1271 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1272 log_info("sm: store remote CSRK"); 1273 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1274 le_device_db_remote_counter_set(le_db_index, 0); 1275 } 1276 1277 // store encryption information 1278 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1279 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1280 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1281 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1282 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1283 } 1284 } 1285 1286 // keep le_db_index 1287 sm_conn->sm_le_db_index = le_db_index; 1288 } 1289 1290 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1291 setup->sm_pairing_failed_reason = reason; 1292 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1293 } 1294 1295 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1296 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1297 } 1298 1299 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1300 1301 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1302 1303 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1304 if (sm_conn->sm_role){ 1305 // Responder 1306 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1307 } else { 1308 // Initiator role 1309 switch (setup->sm_stk_generation_method){ 1310 case JUST_WORKS: 1311 sm_sc_prepare_dhkey_check(sm_conn); 1312 break; 1313 1314 case NK_BOTH_INPUT: 1315 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1316 break; 1317 case PK_INIT_INPUT: 1318 case PK_RESP_INPUT: 1319 case OK_BOTH_INPUT: 1320 if (setup->sm_passkey_bit < 20) { 1321 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1322 } else { 1323 sm_sc_prepare_dhkey_check(sm_conn); 1324 } 1325 break; 1326 case OOB: 1327 // TODO: implement SC OOB 1328 break; 1329 } 1330 } 1331 } 1332 1333 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1334 return sm_cmac_sc_buffer[offset]; 1335 } 1336 1337 static void sm_sc_cmac_done(uint8_t * hash){ 1338 log_info("sm_sc_cmac_done: "); 1339 log_info_hexdump(hash, 16); 1340 1341 sm_connection_t * sm_conn = sm_cmac_connection; 1342 sm_cmac_connection = NULL; 1343 1344 switch (sm_conn->sm_engine_state){ 1345 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1346 memcpy(setup->sm_local_confirm, hash, 16); 1347 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1348 break; 1349 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1350 // check 1351 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1352 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1353 break; 1354 } 1355 sm_sc_state_after_receiving_random(sm_conn); 1356 break; 1357 case SM_SC_W4_CALCULATE_G2: { 1358 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1359 big_endian_store_32(setup->sm_tk, 12, vab); 1360 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1361 sm_trigger_user_response(sm_conn); 1362 break; 1363 } 1364 case SM_SC_W4_CALCULATE_F5_SALT: 1365 memcpy(setup->sm_t, hash, 16); 1366 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1367 break; 1368 case SM_SC_W4_CALCULATE_F5_MACKEY: 1369 memcpy(setup->sm_mackey, hash, 16); 1370 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1371 break; 1372 case SM_SC_W4_CALCULATE_F5_LTK: 1373 memcpy(setup->sm_ltk, hash, 16); 1374 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1375 break; 1376 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1377 memcpy(setup->sm_local_dhkey_check, hash, 16); 1378 if (sm_conn->sm_role){ 1379 // responder 1380 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1381 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1382 } else { 1383 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1384 } 1385 } else { 1386 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1387 } 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_conn, SM_REASON_DHKEY_CHECK_FAILED); 1392 break; 1393 } 1394 if (sm_conn->sm_role){ 1395 // responder 1396 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1397 } else { 1398 // initiator 1399 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1400 } 1401 break; 1402 default: 1403 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1404 break; 1405 } 1406 sm_run(); 1407 } 1408 1409 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){ 1410 const uint16_t message_len = 65; 1411 sm_cmac_connection = sm_conn; 1412 memcpy(sm_cmac_sc_buffer, u, 32); 1413 memcpy(sm_cmac_sc_buffer+32, v, 32); 1414 sm_cmac_sc_buffer[64] = z; 1415 log_info("f4 key"); 1416 log_info_hexdump(x, 16); 1417 log_info("f4 message"); 1418 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1419 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1420 } 1421 1422 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1423 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1424 static const uint8_t f5_length[] = { 0x01, 0x00}; 1425 1426 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1427 #ifdef USE_MBEDTLS_FOR_ECDH 1428 // da * Pb 1429 mbedtls_ecp_group grp; 1430 mbedtls_ecp_group_init( &grp ); 1431 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1432 mbedtls_ecp_point Q; 1433 mbedtls_ecp_point_init( &Q ); 1434 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1435 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1436 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1437 mbedtls_ecp_point DH; 1438 mbedtls_ecp_point_init( &DH ); 1439 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1440 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1441 #endif 1442 log_info("dhkey"); 1443 log_info_hexdump(dhkey, 32); 1444 } 1445 1446 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1447 // calculate DHKEY 1448 sm_key256_t dhkey; 1449 sm_sc_calculate_dhkey(dhkey); 1450 1451 // calculate salt for f5 1452 const uint16_t message_len = 32; 1453 sm_cmac_connection = sm_conn; 1454 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1455 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1456 } 1457 1458 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){ 1459 const uint16_t message_len = 53; 1460 sm_cmac_connection = sm_conn; 1461 1462 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1463 sm_cmac_sc_buffer[0] = 0; 1464 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1465 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1466 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1467 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1468 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1469 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1470 log_info("f5 key"); 1471 log_info_hexdump(t, 16); 1472 log_info("f5 message for MacKey"); 1473 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1474 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1475 } 1476 1477 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1478 sm_key56_t bd_addr_master, bd_addr_slave; 1479 bd_addr_master[0] = setup->sm_m_addr_type; 1480 bd_addr_slave[0] = setup->sm_s_addr_type; 1481 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1482 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1483 if (sm_conn->sm_role){ 1484 // responder 1485 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1486 } else { 1487 // initiator 1488 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1489 } 1490 } 1491 1492 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1493 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1494 const uint16_t message_len = 53; 1495 sm_cmac_connection = sm_conn; 1496 sm_cmac_sc_buffer[0] = 1; 1497 // 1..52 setup before 1498 log_info("f5 key"); 1499 log_info_hexdump(t, 16); 1500 log_info("f5 message for LTK"); 1501 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1502 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1503 } 1504 1505 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1506 f5_ltk(sm_conn, setup->sm_t); 1507 } 1508 1509 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){ 1510 const uint16_t message_len = 65; 1511 sm_cmac_connection = sm_conn; 1512 memcpy(sm_cmac_sc_buffer, n1, 16); 1513 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1514 memcpy(sm_cmac_sc_buffer+32, r, 16); 1515 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1516 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1517 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1518 log_info("f6 key"); 1519 log_info_hexdump(w, 16); 1520 log_info("f6 message"); 1521 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1522 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1523 } 1524 1525 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1526 // - U is 256 bits 1527 // - V is 256 bits 1528 // - X is 128 bits 1529 // - Y is 128 bits 1530 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1531 const uint16_t message_len = 80; 1532 sm_cmac_connection = sm_conn; 1533 memcpy(sm_cmac_sc_buffer, u, 32); 1534 memcpy(sm_cmac_sc_buffer+32, v, 32); 1535 memcpy(sm_cmac_sc_buffer+64, y, 16); 1536 log_info("g2 key"); 1537 log_info_hexdump(x, 16); 1538 log_info("g2 message"); 1539 log_info_hexdump(sm_cmac_sc_buffer, sizeof(sm_cmac_sc_buffer)); 1540 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1541 } 1542 1543 static void g2_calculate_engine(sm_connection_t * sm_conn) { 1544 // calc Va if numeric comparison 1545 uint8_t value[32]; 1546 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1547 if (sm_conn->sm_role){ 1548 // responder 1549 g2_engine(sm_conn, setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce);; 1550 } else { 1551 // initiator 1552 g2_engine(sm_conn, value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1553 } 1554 } 1555 1556 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1557 uint8_t z = 0; 1558 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1559 // some form of passkey 1560 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1561 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1562 setup->sm_passkey_bit++; 1563 } 1564 #ifdef USE_MBEDTLS_FOR_ECDH 1565 uint8_t local_qx[32]; 1566 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1567 #endif 1568 f4_engine(sm_conn, local_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1569 } 1570 1571 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1572 uint8_t z = 0; 1573 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1574 // some form of passkey 1575 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1576 // sm_passkey_bit was increased before sending confirm value 1577 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1578 } 1579 #ifdef USE_MBEDTLS_FOR_ECDH 1580 uint8_t local_qx[32]; 1581 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1582 #endif 1583 f4_engine(sm_conn, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 1584 } 1585 1586 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1587 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1588 } 1589 1590 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1591 // calculate DHKCheck 1592 sm_key56_t bd_addr_master, bd_addr_slave; 1593 bd_addr_master[0] = setup->sm_m_addr_type; 1594 bd_addr_slave[0] = setup->sm_s_addr_type; 1595 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1596 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1597 uint8_t iocap_a[3]; 1598 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1599 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1600 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1601 uint8_t iocap_b[3]; 1602 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1603 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1604 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1605 if (sm_conn->sm_role){ 1606 // responder 1607 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); 1608 } else { 1609 // initiator 1610 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); 1611 } 1612 } 1613 1614 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1615 // validate E = f6() 1616 sm_key56_t bd_addr_master, bd_addr_slave; 1617 bd_addr_master[0] = setup->sm_m_addr_type; 1618 bd_addr_slave[0] = setup->sm_s_addr_type; 1619 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1620 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1621 1622 uint8_t iocap_a[3]; 1623 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1624 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1625 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1626 uint8_t iocap_b[3]; 1627 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1628 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1629 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1630 if (sm_conn->sm_role){ 1631 // responder 1632 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); 1633 } else { 1634 // initiator 1635 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); 1636 } 1637 } 1638 #endif 1639 1640 1641 static void sm_run(void){ 1642 1643 btstack_linked_list_iterator_t it; 1644 1645 // assert that we can send at least commands 1646 if (!hci_can_send_command_packet_now()) return; 1647 1648 // 1649 // non-connection related behaviour 1650 // 1651 1652 // distributed key generation 1653 switch (dkg_state){ 1654 case DKG_CALC_IRK: 1655 // already busy? 1656 if (sm_aes128_state == SM_AES128_IDLE) { 1657 // IRK = d1(IR, 1, 0) 1658 sm_key_t d1_prime; 1659 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1660 dkg_next_state(); 1661 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1662 return; 1663 } 1664 break; 1665 case DKG_CALC_DHK: 1666 // already busy? 1667 if (sm_aes128_state == SM_AES128_IDLE) { 1668 // DHK = d1(IR, 3, 0) 1669 sm_key_t d1_prime; 1670 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1671 dkg_next_state(); 1672 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1673 return; 1674 } 1675 break; 1676 default: 1677 break; 1678 } 1679 1680 // random address updates 1681 switch (rau_state){ 1682 case RAU_GET_RANDOM: 1683 rau_next_state(); 1684 sm_random_start(NULL); 1685 return; 1686 case RAU_GET_ENC: 1687 // already busy? 1688 if (sm_aes128_state == SM_AES128_IDLE) { 1689 sm_key_t r_prime; 1690 sm_ah_r_prime(sm_random_address, r_prime); 1691 rau_next_state(); 1692 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1693 return; 1694 } 1695 break; 1696 case RAU_SET_ADDRESS: 1697 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1698 rau_state = RAU_IDLE; 1699 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1700 return; 1701 default: 1702 break; 1703 } 1704 1705 // CMAC 1706 switch (sm_cmac_state){ 1707 case CMAC_CALC_SUBKEYS: 1708 case CMAC_CALC_MI: 1709 case CMAC_CALC_MLAST: 1710 // already busy? 1711 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1712 sm_cmac_handle_aes_engine_ready(); 1713 return; 1714 default: 1715 break; 1716 } 1717 1718 // CSRK Lookup 1719 // -- if csrk lookup ready, find connection that require csrk lookup 1720 if (sm_address_resolution_idle()){ 1721 hci_connections_get_iterator(&it); 1722 while(btstack_linked_list_iterator_has_next(&it)){ 1723 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1724 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1725 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1726 // and start lookup 1727 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); 1728 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1729 break; 1730 } 1731 } 1732 } 1733 1734 // -- if csrk lookup ready, resolved addresses for received addresses 1735 if (sm_address_resolution_idle()) { 1736 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1737 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1738 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1739 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1740 btstack_memory_sm_lookup_entry_free(entry); 1741 } 1742 } 1743 1744 // -- Continue with CSRK device lookup by public or resolvable private address 1745 if (!sm_address_resolution_idle()){ 1746 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1747 while (sm_address_resolution_test < le_device_db_count()){ 1748 int addr_type; 1749 bd_addr_t addr; 1750 sm_key_t irk; 1751 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1752 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1753 1754 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1755 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1756 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1757 break; 1758 } 1759 1760 if (sm_address_resolution_addr_type == 0){ 1761 sm_address_resolution_test++; 1762 continue; 1763 } 1764 1765 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1766 1767 log_info("LE Device Lookup: calculate AH"); 1768 log_info_key("IRK", irk); 1769 1770 sm_key_t r_prime; 1771 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1772 sm_address_resolution_ah_calculation_active = 1; 1773 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1774 return; 1775 } 1776 1777 if (sm_address_resolution_test >= le_device_db_count()){ 1778 log_info("LE Device Lookup: not found"); 1779 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1780 } 1781 } 1782 1783 1784 // 1785 // active connection handling 1786 // -- use loop to handle next connection if lock on setup context is released 1787 1788 while (1) { 1789 1790 // Find connections that requires setup context and make active if no other is locked 1791 hci_connections_get_iterator(&it); 1792 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1793 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1794 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1795 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1796 int done = 1; 1797 int err; 1798 int encryption_key_size; 1799 int authenticated; 1800 int authorized; 1801 switch (sm_connection->sm_engine_state) { 1802 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1803 // send packet if possible, 1804 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1805 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1806 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1807 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1808 } else { 1809 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1810 } 1811 // don't lock setup context yet 1812 done = 0; 1813 break; 1814 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1815 sm_init_setup(sm_connection); 1816 // recover pairing request 1817 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1818 err = sm_stk_generation_init(sm_connection); 1819 if (err){ 1820 setup->sm_pairing_failed_reason = err; 1821 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1822 break; 1823 } 1824 sm_timeout_start(sm_connection); 1825 // generate random number first, if we need to show passkey 1826 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1827 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1828 break; 1829 } 1830 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1831 break; 1832 case SM_INITIATOR_PH0_HAS_LTK: 1833 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1834 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1835 &encryption_key_size, &authenticated, &authorized); 1836 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1837 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1838 sm_connection->sm_connection_authenticated = authenticated; 1839 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1840 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1841 break; 1842 case SM_RESPONDER_PH0_RECEIVED_LTK: 1843 // re-establish previously used LTK using Rand and EDIV 1844 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1845 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1846 // re-establish used key encryption size 1847 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1848 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1849 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1850 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1851 log_info("sm: received ltk request with key size %u, authenticated %u", 1852 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1853 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1854 break; 1855 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1856 sm_init_setup(sm_connection); 1857 sm_timeout_start(sm_connection); 1858 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1859 break; 1860 default: 1861 done = 0; 1862 break; 1863 } 1864 if (done){ 1865 sm_active_connection = sm_connection->sm_handle; 1866 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1867 } 1868 } 1869 1870 // 1871 // active connection handling 1872 // 1873 1874 if (sm_active_connection == 0) return; 1875 1876 // assert that we could send a SM PDU - not needed for all of the following 1877 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1878 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1879 return; 1880 } 1881 1882 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1883 if (!connection) return; 1884 1885 sm_key_t plaintext; 1886 int key_distribution_flags; 1887 1888 log_info("sm_run: state %u", connection->sm_engine_state); 1889 1890 // responding state 1891 switch (connection->sm_engine_state){ 1892 1893 // general 1894 case SM_GENERAL_SEND_PAIRING_FAILED: { 1895 uint8_t buffer[2]; 1896 buffer[0] = SM_CODE_PAIRING_FAILED; 1897 buffer[1] = setup->sm_pairing_failed_reason; 1898 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1899 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1900 sm_done_for_handle(connection->sm_handle); 1901 break; 1902 } 1903 1904 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1905 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1906 if (!sm_cmac_ready()) break; 1907 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1908 sm_sc_calculate_local_confirm(connection); 1909 break; 1910 1911 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 1912 if (!sm_cmac_ready()) break; 1913 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 1914 sm_sc_calculate_remote_confirm(connection); 1915 break; 1916 1917 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 1918 if (!sm_cmac_ready()) break; 1919 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 1920 sm_sc_calculate_f6_for_dhkey_check(connection); 1921 break; 1922 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1923 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1924 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 1925 break; 1926 case SM_SC_W2_CALCULATE_F5_SALT: 1927 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 1928 f5_calculate_salt(connection); 1929 break; 1930 case SM_SC_W2_CALCULATE_F5_MACKEY: 1931 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 1932 f5_calculate_mackey(connection); 1933 break; 1934 case SM_SC_W2_CALCULATE_F5_LTK: 1935 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 1936 f5_calculate_ltk(connection); 1937 break; 1938 case SM_SC_W2_CALCULATE_G2: 1939 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 1940 g2_calculate_engine(connection); 1941 break; 1942 1943 #endif 1944 // initiator side 1945 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1946 sm_key_t peer_ltk_flipped; 1947 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1948 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1949 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1950 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1951 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1952 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1953 return; 1954 } 1955 1956 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1957 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1958 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1959 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1960 sm_timeout_reset(connection); 1961 break; 1962 1963 // responder side 1964 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1965 connection->sm_engine_state = SM_RESPONDER_IDLE; 1966 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1967 return; 1968 1969 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1970 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1971 uint8_t buffer[65]; 1972 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1973 // 1974 #ifdef USE_MBEDTLS_FOR_ECDH 1975 uint8_t value[32]; 1976 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1977 reverse_256(value, &buffer[1]); 1978 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1979 reverse_256(value, &buffer[33]); 1980 #endif 1981 // TODO: use random generator to generate nonce 1982 1983 // generate 128-bit nonce 1984 int i; 1985 for (i=0;i<16;i++){ 1986 setup->sm_local_nonce[i] = rand() & 0xff; 1987 } 1988 1989 // stk generation method 1990 // passkey entry: notify app to show passkey or to request passkey 1991 switch (setup->sm_stk_generation_method){ 1992 case JUST_WORKS: 1993 case NK_BOTH_INPUT: 1994 if (connection->sm_role){ 1995 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1996 } else { 1997 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1998 } 1999 break; 2000 case PK_INIT_INPUT: 2001 case PK_RESP_INPUT: 2002 case OK_BOTH_INPUT: 2003 // hack for testing: assume user entered '000000' 2004 // memset(setup->sm_tk, 0, 16); 2005 memcpy(setup->sm_ra, setup->sm_tk, 16); 2006 memcpy(setup->sm_rb, setup->sm_tk, 16); 2007 setup->sm_passkey_bit = 0; 2008 if (connection->sm_role){ 2009 // responder 2010 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2011 } else { 2012 // initiator 2013 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2014 } 2015 sm_trigger_user_response(connection); 2016 break; 2017 case OOB: 2018 // TODO: implement SC OOB 2019 break; 2020 } 2021 2022 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2023 sm_timeout_reset(connection); 2024 break; 2025 } 2026 case SM_SC_SEND_CONFIRMATION: { 2027 uint8_t buffer[17]; 2028 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2029 reverse_128(setup->sm_local_confirm, &buffer[1]); 2030 if (connection->sm_role){ 2031 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2032 } else { 2033 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2034 } 2035 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2036 sm_timeout_reset(connection); 2037 break; 2038 } 2039 case SM_SC_SEND_PAIRING_RANDOM: { 2040 uint8_t buffer[17]; 2041 buffer[0] = SM_CODE_PAIRING_RANDOM; 2042 reverse_128(setup->sm_local_nonce, &buffer[1]); 2043 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2044 if (connection->sm_role){ 2045 // responder 2046 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2047 } else { 2048 // initiator 2049 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2050 } 2051 } else { 2052 if (connection->sm_role){ 2053 // responder 2054 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2055 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2056 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2057 } 2058 } else { 2059 // initiator 2060 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2061 } 2062 } 2063 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2064 sm_timeout_reset(connection); 2065 break; 2066 } 2067 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2068 uint8_t buffer[17]; 2069 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2070 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2071 2072 if (connection->sm_role){ 2073 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2074 } else { 2075 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2076 } 2077 2078 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2079 sm_timeout_reset(connection); 2080 break; 2081 } 2082 2083 #endif 2084 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2085 // echo initiator for now 2086 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2087 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2088 2089 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2090 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2091 if (setup->sm_use_secure_connections){ 2092 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2093 // skip LTK/EDIV for SC 2094 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2095 } 2096 #endif 2097 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); 2098 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); 2099 2100 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2101 sm_timeout_reset(connection); 2102 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2103 if (setup->sm_stk_generation_method == JUST_WORKS){ 2104 sm_trigger_user_response(connection); 2105 } 2106 return; 2107 2108 case SM_PH2_SEND_PAIRING_RANDOM: { 2109 uint8_t buffer[17]; 2110 buffer[0] = SM_CODE_PAIRING_RANDOM; 2111 reverse_128(setup->sm_local_random, &buffer[1]); 2112 if (connection->sm_role){ 2113 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2114 } else { 2115 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2116 } 2117 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2118 sm_timeout_reset(connection); 2119 break; 2120 } 2121 2122 case SM_PH2_GET_RANDOM_TK: 2123 case SM_PH2_C1_GET_RANDOM_A: 2124 case SM_PH2_C1_GET_RANDOM_B: 2125 case SM_PH3_GET_RANDOM: 2126 case SM_PH3_GET_DIV: 2127 sm_next_responding_state(connection); 2128 sm_random_start(connection); 2129 return; 2130 2131 case SM_PH2_C1_GET_ENC_B: 2132 case SM_PH2_C1_GET_ENC_D: 2133 // already busy? 2134 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2135 sm_next_responding_state(connection); 2136 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2137 return; 2138 2139 case SM_PH3_LTK_GET_ENC: 2140 case SM_RESPONDER_PH4_LTK_GET_ENC: 2141 // already busy? 2142 if (sm_aes128_state == SM_AES128_IDLE) { 2143 sm_key_t d_prime; 2144 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2145 sm_next_responding_state(connection); 2146 sm_aes128_start(sm_persistent_er, d_prime, connection); 2147 return; 2148 } 2149 break; 2150 2151 case SM_PH3_CSRK_GET_ENC: 2152 // already busy? 2153 if (sm_aes128_state == SM_AES128_IDLE) { 2154 sm_key_t d_prime; 2155 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2156 sm_next_responding_state(connection); 2157 sm_aes128_start(sm_persistent_er, d_prime, connection); 2158 return; 2159 } 2160 break; 2161 2162 case SM_PH2_C1_GET_ENC_C: 2163 // already busy? 2164 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2165 // calculate m_confirm using aes128 engine - step 1 2166 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); 2167 sm_next_responding_state(connection); 2168 sm_aes128_start(setup->sm_tk, plaintext, connection); 2169 break; 2170 case SM_PH2_C1_GET_ENC_A: 2171 // already busy? 2172 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2173 // calculate confirm using aes128 engine - step 1 2174 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); 2175 sm_next_responding_state(connection); 2176 sm_aes128_start(setup->sm_tk, plaintext, connection); 2177 break; 2178 case SM_PH2_CALC_STK: 2179 // already busy? 2180 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2181 // calculate STK 2182 if (connection->sm_role){ 2183 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2184 } else { 2185 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2186 } 2187 sm_next_responding_state(connection); 2188 sm_aes128_start(setup->sm_tk, plaintext, connection); 2189 break; 2190 case SM_PH3_Y_GET_ENC: 2191 // already busy? 2192 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2193 // PH3B2 - calculate Y from - enc 2194 // Y = dm(DHK, Rand) 2195 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2196 sm_next_responding_state(connection); 2197 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2198 return; 2199 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2200 uint8_t buffer[17]; 2201 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2202 reverse_128(setup->sm_local_confirm, &buffer[1]); 2203 if (connection->sm_role){ 2204 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2205 } else { 2206 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2207 } 2208 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2209 sm_timeout_reset(connection); 2210 return; 2211 } 2212 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2213 sm_key_t stk_flipped; 2214 reverse_128(setup->sm_ltk, stk_flipped); 2215 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2216 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2217 return; 2218 } 2219 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2220 sm_key_t stk_flipped; 2221 reverse_128(setup->sm_ltk, stk_flipped); 2222 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2223 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2224 return; 2225 } 2226 case SM_RESPONDER_PH4_SEND_LTK: { 2227 sm_key_t ltk_flipped; 2228 reverse_128(setup->sm_ltk, ltk_flipped); 2229 connection->sm_engine_state = SM_RESPONDER_IDLE; 2230 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2231 return; 2232 } 2233 case SM_RESPONDER_PH4_Y_GET_ENC: 2234 // already busy? 2235 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2236 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2237 // Y = dm(DHK, Rand) 2238 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2239 sm_next_responding_state(connection); 2240 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2241 return; 2242 2243 case SM_PH3_DISTRIBUTE_KEYS: 2244 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2245 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2246 uint8_t buffer[17]; 2247 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2248 reverse_128(setup->sm_ltk, &buffer[1]); 2249 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2250 sm_timeout_reset(connection); 2251 return; 2252 } 2253 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2254 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2255 uint8_t buffer[11]; 2256 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2257 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2258 reverse_64(setup->sm_local_rand, &buffer[3]); 2259 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2260 sm_timeout_reset(connection); 2261 return; 2262 } 2263 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2264 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2265 uint8_t buffer[17]; 2266 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2267 reverse_128(sm_persistent_irk, &buffer[1]); 2268 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2269 sm_timeout_reset(connection); 2270 return; 2271 } 2272 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2273 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2274 bd_addr_t local_address; 2275 uint8_t buffer[8]; 2276 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2277 gap_advertisements_get_address(&buffer[1], local_address); 2278 reverse_bd_addr(local_address, &buffer[2]); 2279 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2280 sm_timeout_reset(connection); 2281 return; 2282 } 2283 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2284 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2285 2286 // hack to reproduce test runs 2287 if (test_use_fixed_local_csrk){ 2288 memset(setup->sm_local_csrk, 0xcc, 16); 2289 } 2290 2291 uint8_t buffer[17]; 2292 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2293 reverse_128(setup->sm_local_csrk, &buffer[1]); 2294 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2295 sm_timeout_reset(connection); 2296 return; 2297 } 2298 2299 // keys are sent 2300 if (connection->sm_role){ 2301 // slave -> receive master keys if any 2302 if (sm_key_distribution_all_received(connection)){ 2303 sm_key_distribution_handle_all_received(connection); 2304 connection->sm_engine_state = SM_RESPONDER_IDLE; 2305 sm_done_for_handle(connection->sm_handle); 2306 } else { 2307 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2308 } 2309 } else { 2310 // master -> all done 2311 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2312 sm_done_for_handle(connection->sm_handle); 2313 } 2314 break; 2315 2316 default: 2317 break; 2318 } 2319 2320 // check again if active connection was released 2321 if (sm_active_connection) break; 2322 } 2323 } 2324 2325 // note: aes engine is ready as we just got the aes result 2326 static void sm_handle_encryption_result(uint8_t * data){ 2327 2328 sm_aes128_state = SM_AES128_IDLE; 2329 2330 if (sm_address_resolution_ah_calculation_active){ 2331 sm_address_resolution_ah_calculation_active = 0; 2332 // compare calulated address against connecting device 2333 uint8_t hash[3]; 2334 reverse_24(data, hash); 2335 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2336 log_info("LE Device Lookup: matched resolvable private address"); 2337 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2338 return; 2339 } 2340 // no match, try next 2341 sm_address_resolution_test++; 2342 return; 2343 } 2344 2345 switch (dkg_state){ 2346 case DKG_W4_IRK: 2347 reverse_128(data, sm_persistent_irk); 2348 log_info_key("irk", sm_persistent_irk); 2349 dkg_next_state(); 2350 return; 2351 case DKG_W4_DHK: 2352 reverse_128(data, sm_persistent_dhk); 2353 log_info_key("dhk", sm_persistent_dhk); 2354 dkg_next_state(); 2355 // SM Init Finished 2356 return; 2357 default: 2358 break; 2359 } 2360 2361 switch (rau_state){ 2362 case RAU_W4_ENC: 2363 reverse_24(data, &sm_random_address[3]); 2364 rau_next_state(); 2365 return; 2366 default: 2367 break; 2368 } 2369 2370 switch (sm_cmac_state){ 2371 case CMAC_W4_SUBKEYS: 2372 case CMAC_W4_MI: 2373 case CMAC_W4_MLAST: 2374 { 2375 sm_key_t t; 2376 reverse_128(data, t); 2377 sm_cmac_handle_encryption_result(t); 2378 } 2379 return; 2380 default: 2381 break; 2382 } 2383 2384 // retrieve sm_connection provided to sm_aes128_start_encryption 2385 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2386 if (!connection) return; 2387 switch (connection->sm_engine_state){ 2388 case SM_PH2_C1_W4_ENC_A: 2389 case SM_PH2_C1_W4_ENC_C: 2390 { 2391 sm_key_t t2; 2392 reverse_128(data, t2); 2393 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2394 } 2395 sm_next_responding_state(connection); 2396 return; 2397 case SM_PH2_C1_W4_ENC_B: 2398 reverse_128(data, setup->sm_local_confirm); 2399 log_info_key("c1!", setup->sm_local_confirm); 2400 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2401 return; 2402 case SM_PH2_C1_W4_ENC_D: 2403 { 2404 sm_key_t peer_confirm_test; 2405 reverse_128(data, peer_confirm_test); 2406 log_info_key("c1!", peer_confirm_test); 2407 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2408 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2409 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2410 return; 2411 } 2412 if (connection->sm_role){ 2413 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2414 } else { 2415 connection->sm_engine_state = SM_PH2_CALC_STK; 2416 } 2417 } 2418 return; 2419 case SM_PH2_W4_STK: 2420 reverse_128(data, setup->sm_ltk); 2421 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2422 log_info_key("stk", setup->sm_ltk); 2423 if (connection->sm_role){ 2424 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2425 } else { 2426 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2427 } 2428 return; 2429 case SM_PH3_Y_W4_ENC:{ 2430 sm_key_t y128; 2431 reverse_128(data, y128); 2432 setup->sm_local_y = big_endian_read_16(y128, 14); 2433 log_info_hex16("y", setup->sm_local_y); 2434 // PH3B3 - calculate EDIV 2435 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2436 log_info_hex16("ediv", setup->sm_local_ediv); 2437 // PH3B4 - calculate LTK - enc 2438 // LTK = d1(ER, DIV, 0)) 2439 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2440 return; 2441 } 2442 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2443 sm_key_t y128; 2444 reverse_128(data, y128); 2445 setup->sm_local_y = big_endian_read_16(y128, 14); 2446 log_info_hex16("y", setup->sm_local_y); 2447 2448 // PH3B3 - calculate DIV 2449 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2450 log_info_hex16("ediv", setup->sm_local_ediv); 2451 // PH3B4 - calculate LTK - enc 2452 // LTK = d1(ER, DIV, 0)) 2453 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2454 return; 2455 } 2456 case SM_PH3_LTK_W4_ENC: 2457 reverse_128(data, setup->sm_ltk); 2458 log_info_key("ltk", setup->sm_ltk); 2459 // calc CSRK next 2460 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2461 return; 2462 case SM_PH3_CSRK_W4_ENC: 2463 reverse_128(data, setup->sm_local_csrk); 2464 log_info_key("csrk", setup->sm_local_csrk); 2465 if (setup->sm_key_distribution_send_set){ 2466 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2467 } else { 2468 // no keys to send, just continue 2469 if (connection->sm_role){ 2470 // slave -> receive master keys 2471 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2472 } else { 2473 // master -> all done 2474 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2475 sm_done_for_handle(connection->sm_handle); 2476 } 2477 } 2478 return; 2479 case SM_RESPONDER_PH4_LTK_W4_ENC: 2480 reverse_128(data, setup->sm_ltk); 2481 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2482 log_info_key("ltk", setup->sm_ltk); 2483 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2484 return; 2485 default: 2486 break; 2487 } 2488 } 2489 2490 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2491 static void sm_handle_random_result(uint8_t * data){ 2492 2493 switch (rau_state){ 2494 case RAU_W4_RANDOM: 2495 // non-resolvable vs. resolvable 2496 switch (gap_random_adress_type){ 2497 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2498 // resolvable: use random as prand and calc address hash 2499 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2500 memcpy(sm_random_address, data, 3); 2501 sm_random_address[0] &= 0x3f; 2502 sm_random_address[0] |= 0x40; 2503 rau_state = RAU_GET_ENC; 2504 break; 2505 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2506 default: 2507 // "The two most significant bits of the address shall be equal to ‘0’"" 2508 memcpy(sm_random_address, data, 6); 2509 sm_random_address[0] &= 0x3f; 2510 rau_state = RAU_SET_ADDRESS; 2511 break; 2512 } 2513 return; 2514 default: 2515 break; 2516 } 2517 2518 // retrieve sm_connection provided to sm_random_start 2519 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2520 if (!connection) return; 2521 switch (connection->sm_engine_state){ 2522 case SM_PH2_W4_RANDOM_TK: 2523 { 2524 // map random to 0-999999 without speding much cycles on a modulus operation 2525 uint32_t tk = little_endian_read_32(data,0); 2526 tk = tk & 0xfffff; // 1048575 2527 if (tk >= 999999){ 2528 tk = tk - 999999; 2529 } 2530 sm_reset_tk(); 2531 big_endian_store_32(setup->sm_tk, 12, tk); 2532 if (connection->sm_role){ 2533 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2534 } else { 2535 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2536 sm_trigger_user_response(connection); 2537 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2538 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2539 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2540 } 2541 } 2542 return; 2543 } 2544 case SM_PH2_C1_W4_RANDOM_A: 2545 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2546 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2547 return; 2548 case SM_PH2_C1_W4_RANDOM_B: 2549 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2550 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2551 return; 2552 case SM_PH3_W4_RANDOM: 2553 reverse_64(data, setup->sm_local_rand); 2554 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2555 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2556 // no db for authenticated flag hack: store flag in bit 4 of LSB 2557 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2558 connection->sm_engine_state = SM_PH3_GET_DIV; 2559 return; 2560 case SM_PH3_W4_DIV: 2561 // use 16 bit from random value as div 2562 setup->sm_local_div = big_endian_read_16(data, 0); 2563 log_info_hex16("div", setup->sm_local_div); 2564 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2565 return; 2566 default: 2567 break; 2568 } 2569 } 2570 2571 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2572 2573 sm_connection_t * sm_conn; 2574 hci_con_handle_t con_handle; 2575 2576 switch (packet_type) { 2577 2578 case HCI_EVENT_PACKET: 2579 switch (hci_event_packet_get_type(packet)) { 2580 2581 case BTSTACK_EVENT_STATE: 2582 // bt stack activated, get started 2583 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2584 log_info("HCI Working!"); 2585 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2586 rau_state = RAU_IDLE; 2587 sm_run(); 2588 } 2589 break; 2590 2591 case HCI_EVENT_LE_META: 2592 switch (packet[2]) { 2593 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2594 2595 log_info("sm: connected"); 2596 2597 if (packet[3]) return; // connection failed 2598 2599 con_handle = little_endian_read_16(packet, 4); 2600 sm_conn = sm_get_connection_for_handle(con_handle); 2601 if (!sm_conn) break; 2602 2603 sm_conn->sm_handle = con_handle; 2604 sm_conn->sm_role = packet[6]; 2605 sm_conn->sm_peer_addr_type = packet[7]; 2606 reverse_bd_addr(&packet[8], 2607 sm_conn->sm_peer_address); 2608 2609 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2610 2611 // reset security properties 2612 sm_conn->sm_connection_encrypted = 0; 2613 sm_conn->sm_connection_authenticated = 0; 2614 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2615 sm_conn->sm_le_db_index = -1; 2616 2617 // prepare CSRK lookup (does not involve setup) 2618 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2619 2620 // just connected -> everything else happens in sm_run() 2621 if (sm_conn->sm_role){ 2622 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2623 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2624 if (sm_slave_request_security) { 2625 // request security if requested by app 2626 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2627 } else { 2628 // otherwise, wait for pairing request 2629 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2630 } 2631 } 2632 break; 2633 } else { 2634 // master 2635 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2636 } 2637 break; 2638 2639 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2640 con_handle = little_endian_read_16(packet, 3); 2641 sm_conn = sm_get_connection_for_handle(con_handle); 2642 if (!sm_conn) break; 2643 2644 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2645 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2646 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2647 break; 2648 } 2649 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2650 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2651 break; 2652 } 2653 2654 // assume that we don't have a LTK for ediv == 0 and random == null 2655 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2656 log_info("LTK Request: ediv & random are empty"); 2657 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2658 break; 2659 } 2660 2661 // store rand and ediv 2662 reverse_64(&packet[5], sm_conn->sm_local_rand); 2663 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2664 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2665 break; 2666 2667 default: 2668 break; 2669 } 2670 break; 2671 2672 case HCI_EVENT_ENCRYPTION_CHANGE: 2673 con_handle = little_endian_read_16(packet, 3); 2674 sm_conn = sm_get_connection_for_handle(con_handle); 2675 if (!sm_conn) break; 2676 2677 sm_conn->sm_connection_encrypted = packet[5]; 2678 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2679 sm_conn->sm_actual_encryption_key_size); 2680 log_info("event handler, state %u", sm_conn->sm_engine_state); 2681 if (!sm_conn->sm_connection_encrypted) break; 2682 // continue if part of initial pairing 2683 switch (sm_conn->sm_engine_state){ 2684 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2685 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2686 sm_done_for_handle(sm_conn->sm_handle); 2687 break; 2688 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2689 if (sm_conn->sm_role){ 2690 // slave 2691 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2692 } else { 2693 // master 2694 if (sm_key_distribution_all_received(sm_conn)){ 2695 // skip receiving keys as there are none 2696 sm_key_distribution_handle_all_received(sm_conn); 2697 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2698 } else { 2699 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2700 } 2701 } 2702 break; 2703 default: 2704 break; 2705 } 2706 break; 2707 2708 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2709 con_handle = little_endian_read_16(packet, 3); 2710 sm_conn = sm_get_connection_for_handle(con_handle); 2711 if (!sm_conn) break; 2712 2713 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2714 log_info("event handler, state %u", sm_conn->sm_engine_state); 2715 // continue if part of initial pairing 2716 switch (sm_conn->sm_engine_state){ 2717 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2718 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2719 sm_done_for_handle(sm_conn->sm_handle); 2720 break; 2721 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2722 if (sm_conn->sm_role){ 2723 // slave 2724 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2725 } else { 2726 // master 2727 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2728 } 2729 break; 2730 default: 2731 break; 2732 } 2733 break; 2734 2735 2736 case HCI_EVENT_DISCONNECTION_COMPLETE: 2737 con_handle = little_endian_read_16(packet, 3); 2738 sm_done_for_handle(con_handle); 2739 sm_conn = sm_get_connection_for_handle(con_handle); 2740 if (!sm_conn) break; 2741 2742 // delete stored bonding on disconnect with authentication failure in ph0 2743 if (sm_conn->sm_role == 0 2744 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2745 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2746 le_device_db_remove(sm_conn->sm_le_db_index); 2747 } 2748 2749 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2750 sm_conn->sm_handle = 0; 2751 break; 2752 2753 case HCI_EVENT_COMMAND_COMPLETE: 2754 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2755 sm_handle_encryption_result(&packet[6]); 2756 break; 2757 } 2758 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2759 sm_handle_random_result(&packet[6]); 2760 break; 2761 } 2762 break; 2763 default: 2764 break; 2765 } 2766 break; 2767 default: 2768 break; 2769 } 2770 2771 sm_run(); 2772 } 2773 2774 static inline int sm_calc_actual_encryption_key_size(int other){ 2775 if (other < sm_min_encryption_key_size) return 0; 2776 if (other < sm_max_encryption_key_size) return other; 2777 return sm_max_encryption_key_size; 2778 } 2779 2780 static int sm_passkey_used(stk_generation_method_t method){ 2781 switch (method){ 2782 case PK_RESP_INPUT: 2783 case PK_INIT_INPUT: 2784 case OK_BOTH_INPUT: 2785 return 1; 2786 default: 2787 return 0; 2788 } 2789 } 2790 2791 /** 2792 * @return ok 2793 */ 2794 static int sm_validate_stk_generation_method(void){ 2795 // check if STK generation method is acceptable by client 2796 switch (setup->sm_stk_generation_method){ 2797 case JUST_WORKS: 2798 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2799 case PK_RESP_INPUT: 2800 case PK_INIT_INPUT: 2801 case OK_BOTH_INPUT: 2802 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2803 case OOB: 2804 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2805 case NK_BOTH_INPUT: 2806 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2807 return 1; 2808 default: 2809 return 0; 2810 } 2811 } 2812 2813 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2814 2815 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2816 sm_run(); 2817 } 2818 2819 if (packet_type != SM_DATA_PACKET) return; 2820 2821 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2822 if (!sm_conn) return; 2823 2824 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2825 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2826 return; 2827 } 2828 2829 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2830 2831 int err; 2832 2833 switch (sm_conn->sm_engine_state){ 2834 2835 // a sm timeout requries a new physical connection 2836 case SM_GENERAL_TIMEOUT: 2837 return; 2838 2839 // Initiator 2840 case SM_INITIATOR_CONNECTED: 2841 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2842 sm_pdu_received_in_wrong_state(sm_conn); 2843 break; 2844 } 2845 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2846 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2847 break; 2848 } 2849 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2850 uint16_t ediv; 2851 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2852 if (ediv){ 2853 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2854 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2855 } else { 2856 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2857 } 2858 break; 2859 } 2860 // otherwise, store security request 2861 sm_conn->sm_security_request_received = 1; 2862 break; 2863 2864 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2865 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2866 sm_pdu_received_in_wrong_state(sm_conn); 2867 break; 2868 } 2869 // store pairing request 2870 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2871 err = sm_stk_generation_init(sm_conn); 2872 if (err){ 2873 setup->sm_pairing_failed_reason = err; 2874 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2875 break; 2876 } 2877 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2878 if (setup->sm_use_secure_connections){ 2879 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2880 if (setup->sm_stk_generation_method == JUST_WORKS){ 2881 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2882 sm_trigger_user_response(sm_conn); 2883 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2884 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2885 } 2886 } else { 2887 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2888 } 2889 break; 2890 } 2891 #endif 2892 // generate random number first, if we need to show passkey 2893 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2894 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2895 break; 2896 } 2897 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2898 sm_trigger_user_response(sm_conn); 2899 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2900 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2901 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2902 } 2903 break; 2904 2905 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2906 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2907 sm_pdu_received_in_wrong_state(sm_conn); 2908 break; 2909 } 2910 2911 // store s_confirm 2912 reverse_128(&packet[1], setup->sm_peer_confirm); 2913 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2914 break; 2915 2916 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2917 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2918 sm_pdu_received_in_wrong_state(sm_conn); 2919 break;; 2920 } 2921 2922 // received random value 2923 reverse_128(&packet[1], setup->sm_peer_random); 2924 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2925 break; 2926 2927 // Responder 2928 case SM_RESPONDER_IDLE: 2929 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2930 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2931 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2932 sm_pdu_received_in_wrong_state(sm_conn); 2933 break;; 2934 } 2935 2936 // store pairing request 2937 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2938 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2939 break; 2940 2941 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2942 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2943 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2944 sm_pdu_received_in_wrong_state(sm_conn); 2945 break; 2946 } 2947 2948 // store public key for DH Key calculation 2949 reverse_256(&packet[01], setup->sm_peer_qx); 2950 reverse_256(&packet[33], setup->sm_peer_qy); 2951 2952 #ifdef USE_MBEDTLS_FOR_ECDH 2953 // validate public key 2954 mbedtls_ecp_group grp; 2955 mbedtls_ecp_group_init( &grp ); 2956 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2957 2958 mbedtls_ecp_point Q; 2959 mbedtls_ecp_point_init( &Q ); 2960 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2961 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2962 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2963 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2964 if (err){ 2965 log_error("sm: peer public key invalid %x", err); 2966 // uses "unspecified reason", there is no "public key invalid" error code 2967 sm_pdu_received_in_wrong_state(sm_conn); 2968 break; 2969 } 2970 #endif 2971 if (sm_conn->sm_role){ 2972 // responder 2973 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2974 } else { 2975 // initiator 2976 // stk generation method 2977 // passkey entry: notify app to show passkey or to request passkey 2978 switch (setup->sm_stk_generation_method){ 2979 case JUST_WORKS: 2980 case NK_BOTH_INPUT: 2981 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2982 break; 2983 case PK_INIT_INPUT: 2984 case PK_RESP_INPUT: 2985 case OK_BOTH_INPUT: 2986 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2987 break; 2988 case OOB: 2989 // TODO: implement SC OOB 2990 break; 2991 } 2992 } 2993 break; 2994 2995 case SM_SC_W4_CONFIRMATION: 2996 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2997 sm_pdu_received_in_wrong_state(sm_conn); 2998 break; 2999 } 3000 // received confirm value 3001 reverse_128(&packet[1], setup->sm_peer_confirm); 3002 3003 if (sm_conn->sm_role){ 3004 // responder 3005 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3006 } else { 3007 // initiator 3008 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3009 } 3010 break; 3011 3012 case SM_SC_W4_PAIRING_RANDOM: 3013 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3014 sm_pdu_received_in_wrong_state(sm_conn); 3015 break; 3016 } 3017 3018 // received random value 3019 reverse_128(&packet[1], setup->sm_peer_nonce); 3020 3021 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3022 // only check for JUST WORK/NC in initiator role AND passkey entry 3023 int passkey_entry = sm_passkey_used(setup->sm_stk_generation_method); 3024 if (sm_conn->sm_role || passkey_entry) { 3025 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3026 } 3027 3028 sm_sc_state_after_receiving_random(sm_conn); 3029 break; 3030 3031 case SM_SC_W2_CALCULATE_G2: 3032 case SM_SC_W4_CALCULATE_G2: 3033 case SM_SC_W2_CALCULATE_F5_SALT: 3034 case SM_SC_W4_CALCULATE_F5_SALT: 3035 case SM_SC_W2_CALCULATE_F5_MACKEY: 3036 case SM_SC_W4_CALCULATE_F5_MACKEY: 3037 case SM_SC_W2_CALCULATE_F5_LTK: 3038 case SM_SC_W4_CALCULATE_F5_LTK: 3039 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3040 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3041 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3042 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3043 sm_pdu_received_in_wrong_state(sm_conn); 3044 break; 3045 } 3046 // store DHKey Check 3047 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3048 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3049 3050 // have we been only waiting for dhkey check command? 3051 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3052 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3053 } 3054 break; 3055 #endif 3056 3057 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3058 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3059 sm_pdu_received_in_wrong_state(sm_conn); 3060 break; 3061 } 3062 3063 // received confirm value 3064 reverse_128(&packet[1], setup->sm_peer_confirm); 3065 3066 // notify client to hide shown passkey 3067 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3068 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3069 } 3070 3071 // handle user cancel pairing? 3072 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3073 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3074 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3075 break; 3076 } 3077 3078 // wait for user action? 3079 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3080 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3081 break; 3082 } 3083 3084 // calculate and send local_confirm 3085 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3086 break; 3087 3088 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3089 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3090 sm_pdu_received_in_wrong_state(sm_conn); 3091 break;; 3092 } 3093 3094 // received random value 3095 reverse_128(&packet[1], setup->sm_peer_random); 3096 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3097 break; 3098 3099 case SM_PH3_RECEIVE_KEYS: 3100 switch(packet[0]){ 3101 case SM_CODE_ENCRYPTION_INFORMATION: 3102 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3103 reverse_128(&packet[1], setup->sm_peer_ltk); 3104 break; 3105 3106 case SM_CODE_MASTER_IDENTIFICATION: 3107 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3108 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3109 reverse_64(&packet[3], setup->sm_peer_rand); 3110 break; 3111 3112 case SM_CODE_IDENTITY_INFORMATION: 3113 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3114 reverse_128(&packet[1], setup->sm_peer_irk); 3115 break; 3116 3117 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3118 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3119 setup->sm_peer_addr_type = packet[1]; 3120 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3121 break; 3122 3123 case SM_CODE_SIGNING_INFORMATION: 3124 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3125 reverse_128(&packet[1], setup->sm_peer_csrk); 3126 break; 3127 default: 3128 // Unexpected PDU 3129 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3130 break; 3131 } 3132 // done with key distribution? 3133 if (sm_key_distribution_all_received(sm_conn)){ 3134 3135 sm_key_distribution_handle_all_received(sm_conn); 3136 3137 if (sm_conn->sm_role){ 3138 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3139 sm_done_for_handle(sm_conn->sm_handle); 3140 } else { 3141 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3142 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3143 if (setup->sm_use_secure_connections){ 3144 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3145 } 3146 #endif 3147 } 3148 } 3149 break; 3150 default: 3151 // Unexpected PDU 3152 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3153 break; 3154 } 3155 3156 // try to send preparared packet 3157 sm_run(); 3158 } 3159 3160 // Security Manager Client API 3161 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3162 sm_get_oob_data = get_oob_data_callback; 3163 } 3164 3165 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3166 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3167 } 3168 3169 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3170 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3171 } 3172 3173 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3174 sm_min_encryption_key_size = min_size; 3175 sm_max_encryption_key_size = max_size; 3176 } 3177 3178 void sm_set_authentication_requirements(uint8_t auth_req){ 3179 sm_auth_req = auth_req; 3180 } 3181 3182 void sm_set_io_capabilities(io_capability_t io_capability){ 3183 sm_io_capabilities = io_capability; 3184 } 3185 3186 void sm_set_request_security(int enable){ 3187 sm_slave_request_security = enable; 3188 } 3189 3190 void sm_set_er(sm_key_t er){ 3191 memcpy(sm_persistent_er, er, 16); 3192 } 3193 3194 void sm_set_ir(sm_key_t ir){ 3195 memcpy(sm_persistent_ir, ir, 16); 3196 } 3197 3198 // Testing support only 3199 void sm_test_set_irk(sm_key_t irk){ 3200 memcpy(sm_persistent_irk, irk, 16); 3201 sm_persistent_irk_ready = 1; 3202 } 3203 3204 void sm_test_use_fixed_local_csrk(void){ 3205 test_use_fixed_local_csrk = 1; 3206 } 3207 3208 void sm_init(void){ 3209 // set some (BTstack default) ER and IR 3210 int i; 3211 sm_key_t er; 3212 sm_key_t ir; 3213 for (i=0;i<16;i++){ 3214 er[i] = 0x30 + i; 3215 ir[i] = 0x90 + i; 3216 } 3217 sm_set_er(er); 3218 sm_set_ir(ir); 3219 // defaults 3220 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3221 | SM_STK_GENERATION_METHOD_OOB 3222 | SM_STK_GENERATION_METHOD_PASSKEY 3223 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3224 3225 sm_max_encryption_key_size = 16; 3226 sm_min_encryption_key_size = 7; 3227 3228 sm_cmac_state = CMAC_IDLE; 3229 dkg_state = DKG_W4_WORKING; 3230 rau_state = RAU_W4_WORKING; 3231 sm_aes128_state = SM_AES128_IDLE; 3232 sm_address_resolution_test = -1; // no private address to resolve yet 3233 sm_address_resolution_ah_calculation_active = 0; 3234 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3235 sm_address_resolution_general_queue = NULL; 3236 3237 gap_random_adress_update_period = 15 * 60 * 1000L; 3238 3239 sm_active_connection = 0; 3240 3241 test_use_fixed_local_csrk = 0; 3242 3243 // register for HCI Events from HCI 3244 hci_event_callback_registration.callback = &sm_event_packet_handler; 3245 hci_add_event_handler(&hci_event_callback_registration); 3246 3247 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3248 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3249 3250 #ifdef USE_MBEDTLS_FOR_ECDH 3251 // TODO: calculate keypair using LE Random Number Generator 3252 // use test keypair from spec initially 3253 mbedtls_ecp_keypair_init(&le_keypair); 3254 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3255 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3256 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3257 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3258 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3259 // print keypair 3260 char buffer[100]; 3261 size_t len; 3262 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3263 log_info("d: %s", buffer); 3264 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3265 log_info("X: %s", buffer); 3266 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3267 log_info("Y: %s", buffer); 3268 #endif 3269 } 3270 3271 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3272 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3273 if (!hci_con) return NULL; 3274 return &hci_con->sm_connection; 3275 } 3276 3277 // @returns 0 if not encrypted, 7-16 otherwise 3278 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3279 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3280 if (!sm_conn) return 0; // wrong connection 3281 if (!sm_conn->sm_connection_encrypted) return 0; 3282 return sm_conn->sm_actual_encryption_key_size; 3283 } 3284 3285 int sm_authenticated(hci_con_handle_t con_handle){ 3286 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3287 if (!sm_conn) return 0; // wrong connection 3288 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3289 return sm_conn->sm_connection_authenticated; 3290 } 3291 3292 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3293 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3294 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3295 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3296 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3297 return sm_conn->sm_connection_authorization_state; 3298 } 3299 3300 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3301 switch (sm_conn->sm_engine_state){ 3302 case SM_GENERAL_IDLE: 3303 case SM_RESPONDER_IDLE: 3304 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3305 sm_run(); 3306 break; 3307 default: 3308 break; 3309 } 3310 } 3311 3312 /** 3313 * @brief Trigger Security Request 3314 */ 3315 void sm_send_security_request(hci_con_handle_t con_handle){ 3316 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3317 if (!sm_conn) return; 3318 sm_send_security_request_for_connection(sm_conn); 3319 } 3320 3321 // request pairing 3322 void sm_request_pairing(hci_con_handle_t con_handle){ 3323 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3324 if (!sm_conn) return; // wrong connection 3325 3326 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3327 if (sm_conn->sm_role){ 3328 sm_send_security_request_for_connection(sm_conn); 3329 } else { 3330 // used as a trigger to start central/master/initiator security procedures 3331 uint16_t ediv; 3332 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3333 switch (sm_conn->sm_irk_lookup_state){ 3334 case IRK_LOOKUP_FAILED: 3335 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3336 break; 3337 case IRK_LOOKUP_SUCCEEDED: 3338 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3339 if (ediv){ 3340 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3341 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3342 } else { 3343 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3344 } 3345 break; 3346 default: 3347 sm_conn->sm_bonding_requested = 1; 3348 break; 3349 } 3350 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3351 sm_conn->sm_bonding_requested = 1; 3352 } 3353 } 3354 sm_run(); 3355 } 3356 3357 // called by client app on authorization request 3358 void sm_authorization_decline(hci_con_handle_t con_handle){ 3359 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3360 if (!sm_conn) return; // wrong connection 3361 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3362 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3363 } 3364 3365 void sm_authorization_grant(hci_con_handle_t con_handle){ 3366 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3367 if (!sm_conn) return; // wrong connection 3368 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3369 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3370 } 3371 3372 // GAP Bonding API 3373 3374 void sm_bonding_decline(hci_con_handle_t con_handle){ 3375 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3376 if (!sm_conn) return; // wrong connection 3377 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3378 3379 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3380 switch (setup->sm_stk_generation_method){ 3381 case PK_RESP_INPUT: 3382 case PK_INIT_INPUT: 3383 case OK_BOTH_INPUT: 3384 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3385 break; 3386 case NK_BOTH_INPUT: 3387 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3388 break; 3389 case JUST_WORKS: 3390 case OOB: 3391 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3392 break; 3393 } 3394 } 3395 sm_run(); 3396 } 3397 3398 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3399 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3400 if (!sm_conn) return; // wrong connection 3401 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3402 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3403 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3404 3405 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3406 if (setup->sm_use_secure_connections){ 3407 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3408 } 3409 #endif 3410 } 3411 3412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3413 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3414 sm_sc_prepare_dhkey_check(sm_conn); 3415 } 3416 #endif 3417 3418 sm_run(); 3419 } 3420 3421 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3422 // for now, it's the same 3423 sm_just_works_confirm(con_handle); 3424 } 3425 3426 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3427 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3428 if (!sm_conn) return; // wrong connection 3429 sm_reset_tk(); 3430 big_endian_store_32(setup->sm_tk, 12, passkey); 3431 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3432 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3433 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3434 } 3435 sm_run(); 3436 } 3437 3438 /** 3439 * @brief Identify device in LE Device DB 3440 * @param handle 3441 * @returns index from le_device_db or -1 if not found/identified 3442 */ 3443 int sm_le_device_index(hci_con_handle_t con_handle ){ 3444 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3445 if (!sm_conn) return -1; 3446 return sm_conn->sm_le_db_index; 3447 } 3448 3449 // GAP LE API 3450 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3451 gap_random_address_update_stop(); 3452 gap_random_adress_type = random_address_type; 3453 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3454 gap_random_address_update_start(); 3455 gap_random_address_trigger(); 3456 } 3457 3458 gap_random_address_type_t gap_random_address_get_mode(void){ 3459 return gap_random_adress_type; 3460 } 3461 3462 void gap_random_address_set_update_period(int period_ms){ 3463 gap_random_adress_update_period = period_ms; 3464 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3465 gap_random_address_update_stop(); 3466 gap_random_address_update_start(); 3467 } 3468 3469 void gap_random_address_set(bd_addr_t addr){ 3470 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3471 memcpy(sm_random_address, addr, 6); 3472 rau_state = RAU_SET_ADDRESS; 3473 sm_run(); 3474 } 3475 3476 /* 3477 * @brief Set Advertisement Paramters 3478 * @param adv_int_min 3479 * @param adv_int_max 3480 * @param adv_type 3481 * @param direct_address_type 3482 * @param direct_address 3483 * @param channel_map 3484 * @param filter_policy 3485 * 3486 * @note own_address_type is used from gap_random_address_set_mode 3487 */ 3488 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3489 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3490 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3491 direct_address_typ, direct_address, channel_map, filter_policy); 3492 } 3493 3494