1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 // TODO: remove software AES 55 #include "rijndael.h" 56 #endif 57 58 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(HAVE_HCI_CONTROLLER_DHKEY_SUPPORT) 59 #define USE_MBEDTLS_FOR_ECDH 60 #endif 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #if !defined(MBEDTLS_CONFIG_FILE) 65 #include "mbedtls/config.h" 66 #else 67 #include MBEDTLS_CONFIG_FILE 68 #endif 69 #if defined(MBEDTLS_PLATFORM_C) 70 #include "mbedtls/platform.h" 71 #else 72 #include <stdio.h> 73 #define mbedtls_printf printf 74 #endif 75 #include "mbedtls/ecp.h" 76 #endif 77 78 // 79 // SM internal types and globals 80 // 81 82 typedef enum { 83 DKG_W4_WORKING, 84 DKG_CALC_IRK, 85 DKG_W4_IRK, 86 DKG_CALC_DHK, 87 DKG_W4_DHK, 88 DKG_READY 89 } derived_key_generation_t; 90 91 typedef enum { 92 RAU_W4_WORKING, 93 RAU_IDLE, 94 RAU_GET_RANDOM, 95 RAU_W4_RANDOM, 96 RAU_GET_ENC, 97 RAU_W4_ENC, 98 RAU_SET_ADDRESS, 99 } random_address_update_t; 100 101 typedef enum { 102 CMAC_IDLE, 103 CMAC_CALC_SUBKEYS, 104 CMAC_W4_SUBKEYS, 105 CMAC_CALC_MI, 106 CMAC_W4_MI, 107 CMAC_CALC_MLAST, 108 CMAC_W4_MLAST 109 } cmac_state_t; 110 111 typedef enum { 112 JUST_WORKS, 113 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 114 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 115 OK_BOTH_INPUT, // Only input on both, both input PK 116 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 117 OOB // OOB available on both sides 118 } stk_generation_method_t; 119 120 typedef enum { 121 SM_USER_RESPONSE_IDLE, 122 SM_USER_RESPONSE_PENDING, 123 SM_USER_RESPONSE_CONFIRM, 124 SM_USER_RESPONSE_PASSKEY, 125 SM_USER_RESPONSE_DECLINE 126 } sm_user_response_t; 127 128 typedef enum { 129 SM_AES128_IDLE, 130 SM_AES128_ACTIVE 131 } sm_aes128_state_t; 132 133 typedef enum { 134 ADDRESS_RESOLUTION_IDLE, 135 ADDRESS_RESOLUTION_GENERAL, 136 ADDRESS_RESOLUTION_FOR_CONNECTION, 137 } address_resolution_mode_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_SUCEEDED, 141 ADDRESS_RESOLUTION_FAILED, 142 } address_resolution_event_t; 143 // 144 // GLOBAL DATA 145 // 146 147 static uint8_t test_use_fixed_local_csrk; 148 149 // configuration 150 static uint8_t sm_accepted_stk_generation_methods; 151 static uint8_t sm_max_encryption_key_size; 152 static uint8_t sm_min_encryption_key_size; 153 static uint8_t sm_auth_req = 0; 154 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 155 static uint8_t sm_slave_request_security; 156 157 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 158 static sm_key_t sm_persistent_er; 159 static sm_key_t sm_persistent_ir; 160 161 // derived from sm_persistent_ir 162 static sm_key_t sm_persistent_dhk; 163 static sm_key_t sm_persistent_irk; 164 static uint8_t sm_persistent_irk_ready = 0; // used for testing 165 static derived_key_generation_t dkg_state; 166 167 // derived from sm_persistent_er 168 // .. 169 170 // random address update 171 static random_address_update_t rau_state; 172 static bd_addr_t sm_random_address; 173 174 // CMAC Calculation: General 175 static cmac_state_t sm_cmac_state; 176 static uint16_t sm_cmac_message_len; 177 static sm_key_t sm_cmac_k; 178 static sm_key_t sm_cmac_x; 179 static sm_key_t sm_cmac_m_last; 180 static uint8_t sm_cmac_block_current; 181 static uint8_t sm_cmac_block_count; 182 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 183 static void (*sm_cmac_done_handler)(uint8_t * hash); 184 185 // CMAC for ATT Signed Writes 186 static uint8_t sm_cmac_header[3]; 187 static const uint8_t * sm_cmac_message; 188 static uint8_t sm_cmac_sign_counter[4]; 189 190 // CMAC for Secure Connection functions 191 #ifdef ENABLE_LE_SECURE_CONNECTIONS 192 static sm_connection_t * sm_cmac_connection; 193 static uint8_t sm_cmac_sc_buffer[80]; 194 #endif 195 196 // resolvable private address lookup / CSRK calculation 197 static int sm_address_resolution_test; 198 static int sm_address_resolution_ah_calculation_active; 199 static uint8_t sm_address_resolution_addr_type; 200 static bd_addr_t sm_address_resolution_address; 201 static void * sm_address_resolution_context; 202 static address_resolution_mode_t sm_address_resolution_mode; 203 static btstack_linked_list_t sm_address_resolution_general_queue; 204 205 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 206 static sm_aes128_state_t sm_aes128_state; 207 static void * sm_aes128_context; 208 209 // random engine. store context (ususally sm_connection_t) 210 static void * sm_random_context; 211 212 // to receive hci events 213 static btstack_packet_callback_registration_t hci_event_callback_registration; 214 215 /* to dispatch sm event */ 216 static btstack_linked_list_t sm_event_handlers; 217 218 // Software ECDH implementation provided by mbedtls 219 #ifdef USE_MBEDTLS_FOR_ECDH 220 mbedtls_ecp_keypair le_keypair; 221 #endif 222 223 // 224 // Volume 3, Part H, Chapter 24 225 // "Security shall be initiated by the Security Manager in the device in the master role. 226 // The device in the slave role shall be the responding device." 227 // -> master := initiator, slave := responder 228 // 229 230 // data needed for security setup 231 typedef struct sm_setup_context { 232 233 btstack_timer_source_t sm_timeout; 234 235 // used in all phases 236 uint8_t sm_pairing_failed_reason; 237 238 // user response, (Phase 1 and/or 2) 239 uint8_t sm_user_response; 240 241 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 242 int sm_key_distribution_send_set; 243 int sm_key_distribution_received_set; 244 245 // Phase 2 (Pairing over SMP) 246 stk_generation_method_t sm_stk_generation_method; 247 sm_key_t sm_tk; 248 uint8_t sm_use_secure_connections; 249 250 sm_key_t sm_c1_t3_value; // c1 calculation 251 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 252 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 253 sm_key_t sm_local_random; 254 sm_key_t sm_local_confirm; 255 sm_key_t sm_peer_random; 256 sm_key_t sm_peer_confirm; 257 uint8_t sm_m_addr_type; // address and type can be removed 258 uint8_t sm_s_addr_type; // '' 259 bd_addr_t sm_m_address; // '' 260 bd_addr_t sm_s_address; // '' 261 sm_key_t sm_ltk; 262 263 #ifdef ENABLE_LE_SECURE_CONNECTIONS 264 uint8_t sm_peer_qx[32]; 265 uint8_t sm_peer_qy[32]; 266 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 267 sm_key_t sm_local_nonce; // might be combined with sm_local_random 268 sm_key_t sm_peer_dhkey_check; 269 sm_key_t sm_local_dhkey_check; 270 sm_key_t sm_ra; 271 sm_key_t sm_rb; 272 sm_key_t sm_mackey; 273 uint8_t sm_passkey_bit; 274 #endif 275 276 // Phase 3 277 278 // key distribution, we generate 279 uint16_t sm_local_y; 280 uint16_t sm_local_div; 281 uint16_t sm_local_ediv; 282 uint8_t sm_local_rand[8]; 283 sm_key_t sm_local_ltk; 284 sm_key_t sm_local_csrk; 285 sm_key_t sm_local_irk; 286 // sm_local_address/addr_type not needed 287 288 // key distribution, received from peer 289 uint16_t sm_peer_y; 290 uint16_t sm_peer_div; 291 uint16_t sm_peer_ediv; 292 uint8_t sm_peer_rand[8]; 293 sm_key_t sm_peer_ltk; 294 sm_key_t sm_peer_irk; 295 sm_key_t sm_peer_csrk; 296 uint8_t sm_peer_addr_type; 297 bd_addr_t sm_peer_address; 298 299 } sm_setup_context_t; 300 301 // 302 static sm_setup_context_t the_setup; 303 static sm_setup_context_t * setup = &the_setup; 304 305 // active connection - the one for which the_setup is used for 306 static uint16_t sm_active_connection = 0; 307 308 // @returns 1 if oob data is available 309 // stores oob data in provided 16 byte buffer if not null 310 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 311 312 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 313 static btstack_packet_handler_t sm_client_packet_handler = NULL; 314 315 // horizontal: initiator capabilities 316 // vertial: responder capabilities 317 static const stk_generation_method_t stk_generation_method [5] [5] = { 318 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 319 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 320 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 321 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 322 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 323 }; 324 325 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 326 #ifdef ENABLE_LE_SECURE_CONNECTIONS 327 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 328 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 329 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 330 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 331 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 332 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 333 }; 334 #endif 335 336 static void sm_run(void); 337 static void sm_done_for_handle(hci_con_handle_t con_handle); 338 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 339 static inline int sm_calc_actual_encryption_key_size(int other); 340 static int sm_validate_stk_generation_method(void); 341 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 342 343 static void log_info_hex16(const char * name, uint16_t value){ 344 log_info("%-6s 0x%04x", name, value); 345 } 346 347 // @returns 1 if all bytes are 0 348 static int sm_is_null_random(uint8_t random[8]){ 349 int i; 350 for (i=0; i < 8 ; i++){ 351 if (random[i]) return 0; 352 } 353 return 1; 354 } 355 356 // Key utils 357 static void sm_reset_tk(void){ 358 int i; 359 for (i=0;i<16;i++){ 360 setup->sm_tk[i] = 0; 361 } 362 } 363 364 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 365 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 366 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 367 int i; 368 for (i = max_encryption_size ; i < 16 ; i++){ 369 key[15-i] = 0; 370 } 371 } 372 373 // SMP Timeout implementation 374 375 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 376 // the Security Manager Timer shall be reset and started. 377 // 378 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 379 // 380 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 381 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 382 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 383 // established. 384 385 static void sm_timeout_handler(btstack_timer_source_t * timer){ 386 log_info("SM timeout"); 387 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 388 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 389 sm_done_for_handle(sm_conn->sm_handle); 390 391 // trigger handling of next ready connection 392 sm_run(); 393 } 394 static void sm_timeout_start(sm_connection_t * sm_conn){ 395 btstack_run_loop_remove_timer(&setup->sm_timeout); 396 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 397 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 398 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 399 btstack_run_loop_add_timer(&setup->sm_timeout); 400 } 401 static void sm_timeout_stop(void){ 402 btstack_run_loop_remove_timer(&setup->sm_timeout); 403 } 404 static void sm_timeout_reset(sm_connection_t * sm_conn){ 405 sm_timeout_stop(); 406 sm_timeout_start(sm_conn); 407 } 408 409 // end of sm timeout 410 411 // GAP Random Address updates 412 static gap_random_address_type_t gap_random_adress_type; 413 static btstack_timer_source_t gap_random_address_update_timer; 414 static uint32_t gap_random_adress_update_period; 415 416 static void gap_random_address_trigger(void){ 417 if (rau_state != RAU_IDLE) return; 418 log_info("gap_random_address_trigger"); 419 rau_state = RAU_GET_RANDOM; 420 sm_run(); 421 } 422 423 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 424 log_info("GAP Random Address Update due"); 425 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 426 btstack_run_loop_add_timer(&gap_random_address_update_timer); 427 gap_random_address_trigger(); 428 } 429 430 static void gap_random_address_update_start(void){ 431 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 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 } 435 436 static void gap_random_address_update_stop(void){ 437 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 438 } 439 440 441 static void sm_random_start(void * context){ 442 sm_random_context = context; 443 hci_send_cmd(&hci_le_rand); 444 } 445 446 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 447 // context is made availabe to aes128 result handler by this 448 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 449 sm_aes128_state = SM_AES128_ACTIVE; 450 sm_key_t key_flipped, plaintext_flipped; 451 reverse_128(key, key_flipped); 452 reverse_128(plaintext, plaintext_flipped); 453 sm_aes128_context = context; 454 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 455 } 456 457 // ah(k,r) helper 458 // r = padding || r 459 // r - 24 bit value 460 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 461 // r'= padding || r 462 memset(r_prime, 0, 16); 463 memcpy(&r_prime[13], r, 3); 464 } 465 466 // d1 helper 467 // d' = padding || r || d 468 // d,r - 16 bit values 469 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 470 // d'= padding || r || d 471 memset(d1_prime, 0, 16); 472 big_endian_store_16(d1_prime, 12, r); 473 big_endian_store_16(d1_prime, 14, d); 474 } 475 476 // dm helper 477 // r’ = padding || r 478 // r - 64 bit value 479 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 480 memset(r_prime, 0, 16); 481 memcpy(&r_prime[8], r, 8); 482 } 483 484 // calculate arguments for first AES128 operation in C1 function 485 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){ 486 487 // p1 = pres || preq || rat’ || iat’ 488 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 489 // cant octet of pres becomes the most significant octet of p1. 490 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 491 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 492 // p1 is 0x05000800000302070710000001010001." 493 494 sm_key_t p1; 495 reverse_56(pres, &p1[0]); 496 reverse_56(preq, &p1[7]); 497 p1[14] = rat; 498 p1[15] = iat; 499 log_info_key("p1", p1); 500 log_info_key("r", r); 501 502 // t1 = r xor p1 503 int i; 504 for (i=0;i<16;i++){ 505 t1[i] = r[i] ^ p1[i]; 506 } 507 log_info_key("t1", t1); 508 } 509 510 // calculate arguments for second AES128 operation in C1 function 511 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 512 // p2 = padding || ia || ra 513 // "The least significant octet of ra becomes the least significant octet of p2 and 514 // the most significant octet of padding becomes the most significant octet of p2. 515 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 516 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 517 518 sm_key_t p2; 519 memset(p2, 0, 16); 520 memcpy(&p2[4], ia, 6); 521 memcpy(&p2[10], ra, 6); 522 log_info_key("p2", p2); 523 524 // c1 = e(k, t2_xor_p2) 525 int i; 526 for (i=0;i<16;i++){ 527 t3[i] = t2[i] ^ p2[i]; 528 } 529 log_info_key("t3", t3); 530 } 531 532 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 533 log_info_key("r1", r1); 534 log_info_key("r2", r2); 535 memcpy(&r_prime[8], &r2[8], 8); 536 memcpy(&r_prime[0], &r1[8], 8); 537 } 538 539 #ifdef ENABLE_LE_SECURE_CONNECTIONS 540 // Software implementations of crypto toolbox for LE Secure Connection 541 // TODO: replace with code to use AES Engine of HCI Controller 542 typedef uint8_t sm_key24_t[3]; 543 typedef uint8_t sm_key56_t[7]; 544 typedef uint8_t sm_key256_t[32]; 545 546 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 547 uint32_t rk[RKLENGTH(KEYBITS)]; 548 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 549 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 550 } 551 552 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 553 memcpy(k1, k0, 16); 554 sm_shift_left_by_one_bit_inplace(16, k1); 555 if (k0[0] & 0x80){ 556 k1[15] ^= 0x87; 557 } 558 memcpy(k2, k1, 16); 559 sm_shift_left_by_one_bit_inplace(16, k2); 560 if (k1[0] & 0x80){ 561 k2[15] ^= 0x87; 562 } 563 } 564 565 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 566 sm_key_t k0, k1, k2, zero; 567 memset(zero, 0, 16); 568 569 aes128_calc_cyphertext(key, zero, k0); 570 calc_subkeys(k0, k1, k2); 571 572 int cmac_block_count = (cmac_message_len + 15) / 16; 573 574 // step 3: .. 575 if (cmac_block_count==0){ 576 cmac_block_count = 1; 577 } 578 579 // step 4: set m_last 580 sm_key_t cmac_m_last; 581 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 582 int i; 583 if (sm_cmac_last_block_complete){ 584 for (i=0;i<16;i++){ 585 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 586 } 587 } else { 588 int valid_octets_in_last_block = cmac_message_len & 0x0f; 589 for (i=0;i<16;i++){ 590 if (i < valid_octets_in_last_block){ 591 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 592 continue; 593 } 594 if (i == valid_octets_in_last_block){ 595 cmac_m_last[i] = 0x80 ^ k2[i]; 596 continue; 597 } 598 cmac_m_last[i] = k2[i]; 599 } 600 } 601 602 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 603 // LOG_KEY(cmac_m_last); 604 605 // Step 5 606 sm_key_t cmac_x; 607 memset(cmac_x, 0, 16); 608 609 // Step 6 610 sm_key_t sm_cmac_y; 611 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 612 for (i=0;i<16;i++){ 613 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 614 } 615 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 616 } 617 for (i=0;i<16;i++){ 618 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 619 } 620 621 // Step 7 622 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 623 } 624 625 const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 626 const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 627 const uint8_t f5_length[] = { 0x01, 0x00}; 628 static void f5(sm_key256_t res, const sm_key256_t w, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 629 // T = AES-CMACSAL_T(W) 630 sm_key_t t; 631 aes_cmac(t, f5_salt, w, 32); 632 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 633 uint8_t buffer[53]; 634 buffer[0] = 0; 635 memcpy(buffer+01, f5_key_id, 4); 636 memcpy(buffer+05, n1, 16); 637 memcpy(buffer+21, n2, 16); 638 memcpy(buffer+37, a1, 7); 639 memcpy(buffer+44, a2, 7); 640 memcpy(buffer+51, f5_length, 2); 641 log_info("f5 DHKEY"); 642 log_info_hexdump(w, 32); 643 log_info("f5 key"); 644 log_info_hexdump(t, 16); 645 log_info("f5 message for MacKey"); 646 log_info_hexdump(buffer, sizeof(buffer)); 647 aes_cmac(res, t, buffer, sizeof(buffer)); 648 // hexdump2(res, 16); 649 // || AES-CMACT (Counter = 1 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the LTK 650 buffer[0] = 1; 651 // hexdump2(buffer, sizeof(buffer)); 652 log_info("f5 message for LTK"); 653 log_info_hexdump(buffer, sizeof(buffer)); 654 aes_cmac(res+16, t, buffer, sizeof(buffer)); 655 // hexdump2(res+16, 16); 656 } 657 658 // f6(W, N1, N2, R, IOcap, A1, A2) = AES-CMACW (N1 || N2 || R || IOcap || A1 || A2 659 // - W is 128 bits 660 // - N1 is 128 bits 661 // - N2 is 128 bits 662 // - R is 128 bits 663 // - IOcap is 24 bits 664 // - A1 is 56 bits 665 // - A2 is 56 bits 666 static void f6(sm_key_t res, 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){ 667 uint8_t buffer[65]; 668 memcpy(buffer, n1, 16); 669 memcpy(buffer+16, n2, 16); 670 memcpy(buffer+32, r, 16); 671 memcpy(buffer+48, io_cap, 3); 672 memcpy(buffer+51, a1, 7); 673 memcpy(buffer+58, a2, 7); 674 log_info("f6 key"); 675 log_info_hexdump(w, 16); 676 log_info("f6 message"); 677 log_info_hexdump(buffer, sizeof(buffer)); 678 aes_cmac(res, w, buffer,sizeof(buffer)); 679 log_info("f6 result"); 680 log_info_hexdump(res, 16); 681 } 682 683 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 684 // - U is 256 bits 685 // - V is 256 bits 686 // - X is 128 bits 687 // - Y is 128 bits 688 static uint32_t g2(const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 689 uint8_t buffer[80]; 690 memcpy(buffer, u, 32); 691 memcpy(buffer+32, v, 32); 692 memcpy(buffer+64, y, 16); 693 sm_key_t cmac; 694 log_info("g2 key"); 695 log_info_hexdump(x, 16); 696 log_info("g2 message"); 697 log_info_hexdump(buffer, sizeof(buffer)); 698 aes_cmac(cmac, x, buffer, sizeof(buffer)); 699 log_info("g2 result"); 700 log_info_hexdump(x, 16); 701 return big_endian_read_32(cmac, 12); 702 } 703 704 #if 0 705 // h6(W, keyID) = AES-CMACW(keyID) 706 // - W is 128 bits 707 // - keyID is 32 bits 708 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 709 uint8_t key_id_buffer[4]; 710 big_endian_store_32(key_id_buffer, 0, key_id); 711 aes_cmac(res, w, key_id_buffer, 4); 712 } 713 #endif 714 #endif 715 716 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){ 717 event[0] = type; 718 event[1] = event_size - 2; 719 little_endian_store_16(event, 2, con_handle); 720 event[4] = addr_type; 721 reverse_bd_addr(address, &event[5]); 722 } 723 724 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 725 if (sm_client_packet_handler) { 726 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 727 } 728 // dispatch to all event handlers 729 btstack_linked_list_iterator_t it; 730 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 731 while (btstack_linked_list_iterator_has_next(&it)){ 732 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 733 entry->callback(packet_type, 0, packet, size); 734 } 735 } 736 737 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 738 uint8_t event[11]; 739 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 740 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 741 } 742 743 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){ 744 uint8_t event[15]; 745 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 746 little_endian_store_32(event, 11, passkey); 747 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 748 } 749 750 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){ 751 uint8_t event[13]; 752 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 753 little_endian_store_16(event, 11, index); 754 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 755 } 756 757 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){ 758 759 uint8_t event[18]; 760 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 761 event[11] = result; 762 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 763 } 764 765 // decide on stk generation based on 766 // - pairing request 767 // - io capabilities 768 // - OOB data availability 769 static void sm_setup_tk(void){ 770 771 // default: just works 772 setup->sm_stk_generation_method = JUST_WORKS; 773 774 #ifdef ENABLE_LE_SECURE_CONNECTIONS 775 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 776 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 777 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 778 memset(setup->sm_ra, 0, 16); 779 memset(setup->sm_rb, 0, 16); 780 #else 781 setup->sm_use_secure_connections = 0; 782 #endif 783 784 // If both devices have not set the MITM option in the Authentication Requirements 785 // Flags, then the IO capabilities shall be ignored and the Just Works association 786 // model shall be used. 787 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 788 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 789 log_info("SM: MITM not required by both -> JUST WORKS"); 790 return; 791 } 792 793 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 794 795 // If both devices have out of band authentication data, then the Authentication 796 // Requirements Flags shall be ignored when selecting the pairing method and the 797 // Out of Band pairing method shall be used. 798 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 799 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 800 log_info("SM: have OOB data"); 801 log_info_key("OOB", setup->sm_tk); 802 setup->sm_stk_generation_method = OOB; 803 return; 804 } 805 806 // Reset TK as it has been setup in sm_init_setup 807 sm_reset_tk(); 808 809 // Also use just works if unknown io capabilites 810 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)){ 811 return; 812 } 813 814 // Otherwise the IO capabilities of the devices shall be used to determine the 815 // pairing method as defined in Table 2.4. 816 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 817 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 818 819 #ifdef ENABLE_LE_SECURE_CONNECTIONS 820 // table not define by default 821 if (setup->sm_use_secure_connections){ 822 generation_method = stk_generation_method_with_secure_connection; 823 } 824 #endif 825 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)]; 826 827 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 828 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); 829 } 830 831 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 832 int flags = 0; 833 if (key_set & SM_KEYDIST_ENC_KEY){ 834 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 835 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 836 } 837 if (key_set & SM_KEYDIST_ID_KEY){ 838 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 839 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 840 } 841 if (key_set & SM_KEYDIST_SIGN){ 842 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 843 } 844 return flags; 845 } 846 847 static void sm_setup_key_distribution(uint8_t key_set){ 848 setup->sm_key_distribution_received_set = 0; 849 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 850 } 851 852 // CSRK Key Lookup 853 854 855 static int sm_address_resolution_idle(void){ 856 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 857 } 858 859 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){ 860 memcpy(sm_address_resolution_address, addr, 6); 861 sm_address_resolution_addr_type = addr_type; 862 sm_address_resolution_test = 0; 863 sm_address_resolution_mode = mode; 864 sm_address_resolution_context = context; 865 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 866 } 867 868 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 869 // check if already in list 870 btstack_linked_list_iterator_t it; 871 sm_lookup_entry_t * entry; 872 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 873 while(btstack_linked_list_iterator_has_next(&it)){ 874 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 875 if (entry->address_type != address_type) continue; 876 if (memcmp(entry->address, address, 6)) continue; 877 // already in list 878 return BTSTACK_BUSY; 879 } 880 entry = btstack_memory_sm_lookup_entry_get(); 881 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 882 entry->address_type = (bd_addr_type_t) address_type; 883 memcpy(entry->address, address, 6); 884 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 885 sm_run(); 886 return 0; 887 } 888 889 // CMAC Implementation using AES128 engine 890 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 891 int i; 892 int carry = 0; 893 for (i=len-1; i >= 0 ; i--){ 894 int new_carry = data[i] >> 7; 895 data[i] = data[i] << 1 | carry; 896 carry = new_carry; 897 } 898 } 899 900 // 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 901 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 902 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 903 } 904 static inline void dkg_next_state(void){ 905 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 906 } 907 static inline void rau_next_state(void){ 908 rau_state = (random_address_update_t) (((int)rau_state) + 1); 909 } 910 911 // CMAC calculation using AES Engine 912 913 static inline void sm_cmac_next_state(void){ 914 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 915 } 916 917 static int sm_cmac_last_block_complete(void){ 918 if (sm_cmac_message_len == 0) return 0; 919 return (sm_cmac_message_len & 0x0f) == 0; 920 } 921 922 static inline uint8_t sm_cmac_message_get_byte(uint16_t offset){ 923 if (offset >= sm_cmac_message_len) { 924 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 925 return 0; 926 } 927 928 offset = sm_cmac_message_len - 1 - offset; 929 930 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 931 if (offset < 3){ 932 return sm_cmac_header[offset]; 933 } 934 int actual_message_len_incl_header = sm_cmac_message_len - 4; 935 if (offset < actual_message_len_incl_header){ 936 return sm_cmac_message[offset - 3]; 937 } 938 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 939 } 940 941 // generic cmac calculation 942 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])){ 943 // Generalized CMAC 944 memcpy(sm_cmac_k, key, 16); 945 memset(sm_cmac_x, 0, 16); 946 sm_cmac_block_current = 0; 947 sm_cmac_message_len = message_len; 948 sm_cmac_done_handler = done_callback; 949 sm_cmac_get_byte = get_byte_callback; 950 951 // step 2: n := ceil(len/const_Bsize); 952 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 953 954 // step 3: .. 955 if (sm_cmac_block_count==0){ 956 sm_cmac_block_count = 1; 957 } 958 959 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 960 961 // first, we need to compute l for k1, k2, and m_last 962 sm_cmac_state = CMAC_CALC_SUBKEYS; 963 964 // let's go 965 sm_run(); 966 } 967 968 // cmac for ATT Message signing 969 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)){ 970 // ATT Message Signing 971 sm_cmac_header[0] = opcode; 972 little_endian_store_16(sm_cmac_header, 1, con_handle); 973 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 974 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 975 sm_cmac_message = message; 976 sm_cmac_general_start(k, total_message_len, &sm_cmac_message_get_byte, done_handler); 977 } 978 979 int sm_cmac_ready(void){ 980 return sm_cmac_state == CMAC_IDLE; 981 } 982 983 static void sm_cmac_handle_aes_engine_ready(void){ 984 switch (sm_cmac_state){ 985 case CMAC_CALC_SUBKEYS: { 986 sm_key_t const_zero; 987 memset(const_zero, 0, 16); 988 sm_cmac_next_state(); 989 sm_aes128_start(sm_cmac_k, const_zero, NULL); 990 break; 991 } 992 case CMAC_CALC_MI: { 993 int j; 994 sm_key_t y; 995 for (j=0;j<16;j++){ 996 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 997 } 998 sm_cmac_block_current++; 999 sm_cmac_next_state(); 1000 sm_aes128_start(sm_cmac_k, y, NULL); 1001 break; 1002 } 1003 case CMAC_CALC_MLAST: { 1004 int i; 1005 sm_key_t y; 1006 for (i=0;i<16;i++){ 1007 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1008 } 1009 log_info_key("Y", y); 1010 sm_cmac_block_current++; 1011 sm_cmac_next_state(); 1012 sm_aes128_start(sm_cmac_k, y, NULL); 1013 break; 1014 } 1015 default: 1016 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1017 break; 1018 } 1019 } 1020 1021 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1022 switch (sm_cmac_state){ 1023 case CMAC_W4_SUBKEYS: { 1024 sm_key_t k1; 1025 memcpy(k1, data, 16); 1026 sm_shift_left_by_one_bit_inplace(16, k1); 1027 if (data[0] & 0x80){ 1028 k1[15] ^= 0x87; 1029 } 1030 sm_key_t k2; 1031 memcpy(k2, k1, 16); 1032 sm_shift_left_by_one_bit_inplace(16, k2); 1033 if (k1[0] & 0x80){ 1034 k2[15] ^= 0x87; 1035 } 1036 1037 log_info_key("k", sm_cmac_k); 1038 log_info_key("k1", k1); 1039 log_info_key("k2", k2); 1040 1041 // step 4: set m_last 1042 int i; 1043 if (sm_cmac_last_block_complete()){ 1044 for (i=0;i<16;i++){ 1045 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1046 } 1047 } else { 1048 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1049 for (i=0;i<16;i++){ 1050 if (i < valid_octets_in_last_block){ 1051 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1052 continue; 1053 } 1054 if (i == valid_octets_in_last_block){ 1055 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1056 continue; 1057 } 1058 sm_cmac_m_last[i] = k2[i]; 1059 } 1060 } 1061 1062 // next 1063 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1064 break; 1065 } 1066 case CMAC_W4_MI: 1067 memcpy(sm_cmac_x, data, 16); 1068 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1069 break; 1070 case CMAC_W4_MLAST: 1071 // done 1072 log_info_key("CMAC", data); 1073 sm_cmac_done_handler(data); 1074 sm_cmac_state = CMAC_IDLE; 1075 break; 1076 default: 1077 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1078 break; 1079 } 1080 } 1081 1082 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1083 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1084 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1085 switch (setup->sm_stk_generation_method){ 1086 case PK_RESP_INPUT: 1087 if (sm_conn->sm_role){ 1088 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1089 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1090 } else { 1091 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)); 1092 } 1093 break; 1094 case PK_INIT_INPUT: 1095 if (sm_conn->sm_role){ 1096 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)); 1097 } else { 1098 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1099 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1100 } 1101 break; 1102 case OK_BOTH_INPUT: 1103 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1104 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1105 break; 1106 case NK_BOTH_INPUT: 1107 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1108 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)); 1109 break; 1110 case JUST_WORKS: 1111 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1112 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1113 break; 1114 case OOB: 1115 // client already provided OOB data, let's skip notification. 1116 break; 1117 } 1118 } 1119 1120 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1121 int recv_flags; 1122 if (sm_conn->sm_role){ 1123 // slave / responder 1124 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1125 } else { 1126 // master / initiator 1127 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1128 } 1129 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1130 return recv_flags == setup->sm_key_distribution_received_set; 1131 } 1132 1133 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1134 if (sm_active_connection == con_handle){ 1135 sm_timeout_stop(); 1136 sm_active_connection = 0; 1137 log_info("sm: connection 0x%x released setup context", con_handle); 1138 } 1139 } 1140 1141 static int sm_key_distribution_flags_for_auth_req(void){ 1142 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1143 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1144 // encryption information only if bonding requested 1145 flags |= SM_KEYDIST_ENC_KEY; 1146 } 1147 return flags; 1148 } 1149 1150 static void sm_init_setup(sm_connection_t * sm_conn){ 1151 1152 // fill in sm setup 1153 sm_reset_tk(); 1154 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1155 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1156 1157 // query client for OOB data 1158 int have_oob_data = 0; 1159 if (sm_get_oob_data) { 1160 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1161 } 1162 1163 sm_pairing_packet_t * local_packet; 1164 if (sm_conn->sm_role){ 1165 // slave 1166 local_packet = &setup->sm_s_pres; 1167 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1168 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1169 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1170 } else { 1171 // master 1172 local_packet = &setup->sm_m_preq; 1173 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1174 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1175 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1176 1177 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1178 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1179 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1180 } 1181 1182 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1183 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1184 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1185 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1186 } 1187 1188 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1189 1190 sm_pairing_packet_t * remote_packet; 1191 int remote_key_request; 1192 if (sm_conn->sm_role){ 1193 // slave / responder 1194 remote_packet = &setup->sm_m_preq; 1195 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1196 } else { 1197 // master / initiator 1198 remote_packet = &setup->sm_s_pres; 1199 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1200 } 1201 1202 // check key size 1203 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1204 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1205 1206 // decide on STK generation method 1207 sm_setup_tk(); 1208 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1209 1210 // check if STK generation method is acceptable by client 1211 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1212 1213 // identical to responder 1214 sm_setup_key_distribution(remote_key_request); 1215 1216 // JUST WORKS doens't provide authentication 1217 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1218 1219 return 0; 1220 } 1221 1222 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1223 1224 // cache and reset context 1225 int matched_device_id = sm_address_resolution_test; 1226 address_resolution_mode_t mode = sm_address_resolution_mode; 1227 void * context = sm_address_resolution_context; 1228 1229 // reset context 1230 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1231 sm_address_resolution_context = NULL; 1232 sm_address_resolution_test = -1; 1233 hci_con_handle_t con_handle = 0; 1234 1235 sm_connection_t * sm_connection; 1236 uint16_t ediv; 1237 switch (mode){ 1238 case ADDRESS_RESOLUTION_GENERAL: 1239 break; 1240 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1241 sm_connection = (sm_connection_t *) context; 1242 con_handle = sm_connection->sm_handle; 1243 switch (event){ 1244 case ADDRESS_RESOLUTION_SUCEEDED: 1245 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1246 sm_connection->sm_le_db_index = matched_device_id; 1247 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1248 if (sm_connection->sm_role) break; 1249 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1250 sm_connection->sm_security_request_received = 0; 1251 sm_connection->sm_bonding_requested = 0; 1252 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1253 if (ediv){ 1254 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1255 } else { 1256 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1257 } 1258 break; 1259 case ADDRESS_RESOLUTION_FAILED: 1260 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1261 if (sm_connection->sm_role) break; 1262 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1263 sm_connection->sm_security_request_received = 0; 1264 sm_connection->sm_bonding_requested = 0; 1265 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1266 break; 1267 } 1268 break; 1269 default: 1270 break; 1271 } 1272 1273 switch (event){ 1274 case ADDRESS_RESOLUTION_SUCEEDED: 1275 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1276 break; 1277 case ADDRESS_RESOLUTION_FAILED: 1278 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1279 break; 1280 } 1281 } 1282 1283 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1284 1285 int le_db_index = -1; 1286 1287 // lookup device based on IRK 1288 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1289 int i; 1290 for (i=0; i < le_device_db_count(); i++){ 1291 sm_key_t irk; 1292 bd_addr_t address; 1293 int address_type; 1294 le_device_db_info(i, &address_type, address, irk); 1295 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1296 log_info("sm: device found for IRK, updating"); 1297 le_db_index = i; 1298 break; 1299 } 1300 } 1301 } 1302 1303 // if not found, lookup via public address if possible 1304 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1305 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1306 int i; 1307 for (i=0; i < le_device_db_count(); i++){ 1308 bd_addr_t address; 1309 int address_type; 1310 le_device_db_info(i, &address_type, address, NULL); 1311 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1312 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1313 log_info("sm: device found for public address, updating"); 1314 le_db_index = i; 1315 break; 1316 } 1317 } 1318 } 1319 1320 // if not found, add to db 1321 if (le_db_index < 0) { 1322 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1323 } 1324 1325 if (le_db_index >= 0){ 1326 le_device_db_local_counter_set(le_db_index, 0); 1327 1328 // store local CSRK 1329 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1330 log_info("sm: store local CSRK"); 1331 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1332 le_device_db_local_counter_set(le_db_index, 0); 1333 } 1334 1335 // store remote CSRK 1336 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1337 log_info("sm: store remote CSRK"); 1338 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1339 le_device_db_remote_counter_set(le_db_index, 0); 1340 } 1341 1342 // store encryption information 1343 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1344 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1345 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1346 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1347 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1348 } 1349 } 1350 1351 // keep le_db_index 1352 sm_conn->sm_le_db_index = le_db_index; 1353 } 1354 1355 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1356 setup->sm_pairing_failed_reason = reason; 1357 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1358 } 1359 1360 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1361 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1362 } 1363 1364 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1365 1366 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1367 if (sm_conn->sm_role){ 1368 // Responder 1369 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1370 } else { 1371 // Initiator role 1372 switch (setup->sm_stk_generation_method){ 1373 case JUST_WORKS: 1374 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1375 break; 1376 1377 case NK_BOTH_INPUT: { 1378 // calc Va if numeric comparison 1379 // TODO: use AES Engine to calculate g2 1380 uint8_t value[32]; 1381 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1382 uint32_t va = g2(value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce) % 1000000; 1383 big_endian_store_32(setup->sm_tk, 12, va); 1384 sm_trigger_user_response(sm_conn); 1385 break; 1386 } 1387 case PK_INIT_INPUT: 1388 case PK_RESP_INPUT: 1389 case OK_BOTH_INPUT: 1390 if (setup->sm_passkey_bit < 20) { 1391 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1392 } else { 1393 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1394 } 1395 break; 1396 case OOB: 1397 // TODO: implement SC OOB 1398 break; 1399 } 1400 } 1401 } 1402 1403 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1404 return sm_cmac_sc_buffer[offset]; 1405 } 1406 1407 static void sm_sc_cmac_done(uint8_t * hash){ 1408 log_info("sm_sc_cmac_done: "); 1409 log_info_hexdump(hash, 16); 1410 1411 switch (sm_cmac_connection->sm_engine_state){ 1412 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1413 memcpy(setup->sm_local_confirm, hash, 16); 1414 sm_cmac_connection->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1415 break; 1416 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1417 // check 1418 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1419 sm_pairing_error(sm_cmac_connection, SM_REASON_CONFIRM_VALUE_FAILED); 1420 break; 1421 } 1422 // next state 1423 sm_sc_state_after_receiving_random(sm_cmac_connection); 1424 break; 1425 default: 1426 log_error("sm_sc_cmac_done in state %u", sm_cmac_connection->sm_engine_state); 1427 break; 1428 } 1429 sm_cmac_connection = 0; 1430 sm_run(); 1431 } 1432 1433 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){ 1434 sm_cmac_connection = sm_conn; 1435 memcpy(sm_cmac_sc_buffer, u, 32); 1436 memcpy(sm_cmac_sc_buffer+32, v, 32); 1437 sm_cmac_sc_buffer[64] = z; 1438 log_info("f4 key"); 1439 log_info_hexdump(x, 16); 1440 log_info("f4 message"); 1441 log_info_hexdump(sm_cmac_sc_buffer, 65); 1442 sm_cmac_general_start(x, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1443 } 1444 1445 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1446 uint8_t z = 0; 1447 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1448 // some form of passkey 1449 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1450 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1451 setup->sm_passkey_bit++; 1452 } 1453 #ifdef USE_MBEDTLS_FOR_ECDH 1454 uint8_t local_qx[32]; 1455 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1456 #endif 1457 f4_engine(sm_conn, local_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1458 } 1459 1460 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1461 uint8_t z = 0; 1462 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1463 // some form of passkey 1464 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1465 // sm_passkey_bit was increased before sending confirm value 1466 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1467 } 1468 #ifdef USE_MBEDTLS_FOR_ECDH 1469 uint8_t local_qx[32]; 1470 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 1471 #endif 1472 f4_engine(sm_conn, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 1473 } 1474 1475 #endif 1476 1477 static void sm_run(void){ 1478 1479 btstack_linked_list_iterator_t it; 1480 1481 // assert that we can send at least commands 1482 if (!hci_can_send_command_packet_now()) return; 1483 1484 // 1485 // non-connection related behaviour 1486 // 1487 1488 // distributed key generation 1489 switch (dkg_state){ 1490 case DKG_CALC_IRK: 1491 // already busy? 1492 if (sm_aes128_state == SM_AES128_IDLE) { 1493 // IRK = d1(IR, 1, 0) 1494 sm_key_t d1_prime; 1495 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1496 dkg_next_state(); 1497 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1498 return; 1499 } 1500 break; 1501 case DKG_CALC_DHK: 1502 // already busy? 1503 if (sm_aes128_state == SM_AES128_IDLE) { 1504 // DHK = d1(IR, 3, 0) 1505 sm_key_t d1_prime; 1506 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1507 dkg_next_state(); 1508 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1509 return; 1510 } 1511 break; 1512 default: 1513 break; 1514 } 1515 1516 // random address updates 1517 switch (rau_state){ 1518 case RAU_GET_RANDOM: 1519 rau_next_state(); 1520 sm_random_start(NULL); 1521 return; 1522 case RAU_GET_ENC: 1523 // already busy? 1524 if (sm_aes128_state == SM_AES128_IDLE) { 1525 sm_key_t r_prime; 1526 sm_ah_r_prime(sm_random_address, r_prime); 1527 rau_next_state(); 1528 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1529 return; 1530 } 1531 break; 1532 case RAU_SET_ADDRESS: 1533 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1534 rau_state = RAU_IDLE; 1535 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1536 return; 1537 default: 1538 break; 1539 } 1540 1541 // CMAC 1542 switch (sm_cmac_state){ 1543 case CMAC_CALC_SUBKEYS: 1544 case CMAC_CALC_MI: 1545 case CMAC_CALC_MLAST: 1546 // already busy? 1547 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1548 sm_cmac_handle_aes_engine_ready(); 1549 return; 1550 default: 1551 break; 1552 } 1553 1554 // CSRK Lookup 1555 // -- if csrk lookup ready, find connection that require csrk lookup 1556 if (sm_address_resolution_idle()){ 1557 hci_connections_get_iterator(&it); 1558 while(btstack_linked_list_iterator_has_next(&it)){ 1559 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1560 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1561 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1562 // and start lookup 1563 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); 1564 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1565 break; 1566 } 1567 } 1568 } 1569 1570 // -- if csrk lookup ready, resolved addresses for received addresses 1571 if (sm_address_resolution_idle()) { 1572 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1573 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1574 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1575 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1576 btstack_memory_sm_lookup_entry_free(entry); 1577 } 1578 } 1579 1580 // -- Continue with CSRK device lookup by public or resolvable private address 1581 if (!sm_address_resolution_idle()){ 1582 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1583 while (sm_address_resolution_test < le_device_db_count()){ 1584 int addr_type; 1585 bd_addr_t addr; 1586 sm_key_t irk; 1587 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1588 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1589 1590 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1591 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1592 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1593 break; 1594 } 1595 1596 if (sm_address_resolution_addr_type == 0){ 1597 sm_address_resolution_test++; 1598 continue; 1599 } 1600 1601 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1602 1603 log_info("LE Device Lookup: calculate AH"); 1604 log_info_key("IRK", irk); 1605 1606 sm_key_t r_prime; 1607 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1608 sm_address_resolution_ah_calculation_active = 1; 1609 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1610 return; 1611 } 1612 1613 if (sm_address_resolution_test >= le_device_db_count()){ 1614 log_info("LE Device Lookup: not found"); 1615 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1616 } 1617 } 1618 1619 1620 // 1621 // active connection handling 1622 // -- use loop to handle next connection if lock on setup context is released 1623 1624 while (1) { 1625 1626 // Find connections that requires setup context and make active if no other is locked 1627 hci_connections_get_iterator(&it); 1628 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1629 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1630 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1631 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1632 int done = 1; 1633 int err; 1634 int encryption_key_size; 1635 int authenticated; 1636 int authorized; 1637 switch (sm_connection->sm_engine_state) { 1638 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1639 // send packet if possible, 1640 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1641 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1642 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1643 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1644 } else { 1645 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1646 } 1647 // don't lock setup context yet 1648 done = 0; 1649 break; 1650 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1651 sm_init_setup(sm_connection); 1652 // recover pairing request 1653 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1654 err = sm_stk_generation_init(sm_connection); 1655 if (err){ 1656 setup->sm_pairing_failed_reason = err; 1657 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1658 break; 1659 } 1660 sm_timeout_start(sm_connection); 1661 // generate random number first, if we need to show passkey 1662 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1663 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1664 break; 1665 } 1666 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1667 break; 1668 case SM_INITIATOR_PH0_HAS_LTK: 1669 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1670 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1671 &encryption_key_size, &authenticated, &authorized); 1672 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1673 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1674 sm_connection->sm_connection_authenticated = authenticated; 1675 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1676 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1677 break; 1678 case SM_RESPONDER_PH0_RECEIVED_LTK: 1679 // re-establish previously used LTK using Rand and EDIV 1680 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1681 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1682 // re-establish used key encryption size 1683 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1684 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1685 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1686 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1687 log_info("sm: received ltk request with key size %u, authenticated %u", 1688 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1689 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1690 break; 1691 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1692 sm_init_setup(sm_connection); 1693 sm_timeout_start(sm_connection); 1694 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1695 break; 1696 default: 1697 done = 0; 1698 break; 1699 } 1700 if (done){ 1701 sm_active_connection = sm_connection->sm_handle; 1702 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1703 } 1704 } 1705 1706 // 1707 // active connection handling 1708 // 1709 1710 if (sm_active_connection == 0) return; 1711 1712 // assert that we could send a SM PDU - not needed for all of the following 1713 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1714 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1715 return; 1716 } 1717 1718 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1719 if (!connection) return; 1720 1721 sm_key_t plaintext; 1722 int key_distribution_flags; 1723 1724 log_info("sm_run: state %u", connection->sm_engine_state); 1725 1726 // responding state 1727 switch (connection->sm_engine_state){ 1728 1729 // general 1730 case SM_GENERAL_SEND_PAIRING_FAILED: { 1731 uint8_t buffer[2]; 1732 buffer[0] = SM_CODE_PAIRING_FAILED; 1733 buffer[1] = setup->sm_pairing_failed_reason; 1734 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1735 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1736 sm_done_for_handle(connection->sm_handle); 1737 break; 1738 } 1739 1740 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1741 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1742 if (!sm_cmac_ready()) break; 1743 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1744 sm_sc_calculate_local_confirm(connection); 1745 break; 1746 1747 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 1748 if (!sm_cmac_ready()) break; 1749 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 1750 sm_sc_calculate_remote_confirm(connection); 1751 break; 1752 #endif 1753 // initiator side 1754 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1755 sm_key_t peer_ltk_flipped; 1756 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1757 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1758 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1759 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1760 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1761 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1762 return; 1763 } 1764 1765 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1766 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1767 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1768 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1769 sm_timeout_reset(connection); 1770 break; 1771 1772 // responder side 1773 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1774 connection->sm_engine_state = SM_RESPONDER_IDLE; 1775 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1776 return; 1777 1778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1779 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1780 uint8_t buffer[65]; 1781 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1782 // 1783 #ifdef USE_MBEDTLS_FOR_ECDH 1784 uint8_t value[32]; 1785 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1786 reverse_256(value, &buffer[1]); 1787 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1788 reverse_256(value, &buffer[33]); 1789 #endif 1790 // TODO: use random generator to generate nonce 1791 1792 // generate 128-bit nonce 1793 int i; 1794 for (i=0;i<16;i++){ 1795 setup->sm_local_nonce[i] = rand() & 0xff; 1796 } 1797 1798 // stk generation method 1799 // passkey entry: notify app to show passkey or to request passkey 1800 switch (setup->sm_stk_generation_method){ 1801 case JUST_WORKS: 1802 case NK_BOTH_INPUT: 1803 if (connection->sm_role){ 1804 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1805 } else { 1806 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1807 } 1808 break; 1809 case PK_INIT_INPUT: 1810 case PK_RESP_INPUT: 1811 case OK_BOTH_INPUT: 1812 // hack for testing: assume user entered '000000' 1813 // memset(setup->sm_tk, 0, 16); 1814 memcpy(setup->sm_ra, setup->sm_tk, 16); 1815 memcpy(setup->sm_rb, setup->sm_tk, 16); 1816 setup->sm_passkey_bit = 0; 1817 if (connection->sm_role){ 1818 // responder 1819 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1820 } else { 1821 // initiator 1822 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1823 } 1824 sm_trigger_user_response(connection); 1825 break; 1826 case OOB: 1827 // TODO: implement SC OOB 1828 break; 1829 } 1830 1831 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1832 sm_timeout_reset(connection); 1833 break; 1834 } 1835 case SM_SC_SEND_CONFIRMATION: { 1836 uint8_t buffer[17]; 1837 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1838 reverse_128(setup->sm_local_confirm, &buffer[1]); 1839 if (connection->sm_role){ 1840 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1841 } else { 1842 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1843 } 1844 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1845 sm_timeout_reset(connection); 1846 break; 1847 } 1848 case SM_SC_SEND_PAIRING_RANDOM: { 1849 uint8_t buffer[17]; 1850 buffer[0] = SM_CODE_PAIRING_RANDOM; 1851 reverse_128(setup->sm_local_nonce, &buffer[1]); 1852 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 1853 if (connection->sm_role){ 1854 // responder 1855 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1856 } else { 1857 // initiator 1858 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1859 } 1860 } else { 1861 if (connection->sm_role){ 1862 // responder 1863 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1864 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 1865 // calc Vb if numeric comparison 1866 // TODO: use AES Engine to calculate g2 1867 uint8_t value[32]; 1868 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1869 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 1870 big_endian_store_32(setup->sm_tk, 12, vb); 1871 sm_trigger_user_response(connection); 1872 } 1873 } else { 1874 // initiator 1875 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1876 } 1877 } 1878 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1879 sm_timeout_reset(connection); 1880 break; 1881 } 1882 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 1883 1884 uint8_t buffer[17]; 1885 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 1886 #ifdef USE_MBEDTLS_FOR_ECDH 1887 // calculate DHKEY 1888 mbedtls_ecp_group grp; 1889 mbedtls_ecp_group_init( &grp ); 1890 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1891 mbedtls_ecp_point Q; 1892 mbedtls_ecp_point_init( &Q ); 1893 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1894 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1895 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1896 1897 // da * Pb 1898 mbedtls_ecp_point DH; 1899 mbedtls_ecp_point_init( &DH ); 1900 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1901 sm_key256_t dhkey; 1902 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1903 log_info("dhkey"); 1904 log_info_hexdump(dhkey, 32); 1905 1906 // calculate LTK + MacKey 1907 sm_key256_t ltk_mackey; 1908 sm_key56_t bd_addr_master, bd_addr_slave; 1909 bd_addr_master[0] = setup->sm_m_addr_type; 1910 bd_addr_slave[0] = setup->sm_s_addr_type; 1911 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1912 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1913 if (connection->sm_role){ 1914 // responder 1915 f5(ltk_mackey, dhkey, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1916 } else { 1917 // initiator 1918 f5(ltk_mackey, dhkey, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1919 } 1920 // store LTK 1921 memcpy(setup->sm_ltk, <k_mackey[16], 16); 1922 1923 // calc DHKCheck 1924 memcpy(setup->sm_mackey, <k_mackey[0], 16); 1925 1926 // TODO: checks 1927 1928 uint8_t iocap_a[3]; 1929 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1930 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1931 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1932 uint8_t iocap_b[3]; 1933 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1934 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1935 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1936 if (connection->sm_role){ 1937 // responder 1938 f6(setup->sm_local_dhkey_check, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1939 } else { 1940 // initiator 1941 f6(setup->sm_local_dhkey_check, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1942 } 1943 #endif 1944 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 1945 if (connection->sm_role){ 1946 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 1947 } else { 1948 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1949 } 1950 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1951 sm_timeout_reset(connection); 1952 break; 1953 } 1954 1955 #endif 1956 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1957 // echo initiator for now 1958 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1959 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1960 1961 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1962 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1963 if (setup->sm_use_secure_connections){ 1964 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1965 // skip LTK/EDIV for SC 1966 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 1967 } 1968 #endif 1969 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); 1970 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); 1971 1972 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1973 sm_timeout_reset(connection); 1974 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 1975 if (setup->sm_stk_generation_method == JUST_WORKS){ 1976 sm_trigger_user_response(connection); 1977 } 1978 return; 1979 1980 case SM_PH2_SEND_PAIRING_RANDOM: { 1981 uint8_t buffer[17]; 1982 buffer[0] = SM_CODE_PAIRING_RANDOM; 1983 reverse_128(setup->sm_local_random, &buffer[1]); 1984 if (connection->sm_role){ 1985 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1986 } else { 1987 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1988 } 1989 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1990 sm_timeout_reset(connection); 1991 break; 1992 } 1993 1994 case SM_PH2_GET_RANDOM_TK: 1995 case SM_PH2_C1_GET_RANDOM_A: 1996 case SM_PH2_C1_GET_RANDOM_B: 1997 case SM_PH3_GET_RANDOM: 1998 case SM_PH3_GET_DIV: 1999 sm_next_responding_state(connection); 2000 sm_random_start(connection); 2001 return; 2002 2003 case SM_PH2_C1_GET_ENC_B: 2004 case SM_PH2_C1_GET_ENC_D: 2005 // already busy? 2006 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2007 sm_next_responding_state(connection); 2008 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2009 return; 2010 2011 case SM_PH3_LTK_GET_ENC: 2012 case SM_RESPONDER_PH4_LTK_GET_ENC: 2013 // already busy? 2014 if (sm_aes128_state == SM_AES128_IDLE) { 2015 sm_key_t d_prime; 2016 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2017 sm_next_responding_state(connection); 2018 sm_aes128_start(sm_persistent_er, d_prime, connection); 2019 return; 2020 } 2021 break; 2022 2023 case SM_PH3_CSRK_GET_ENC: 2024 // already busy? 2025 if (sm_aes128_state == SM_AES128_IDLE) { 2026 sm_key_t d_prime; 2027 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2028 sm_next_responding_state(connection); 2029 sm_aes128_start(sm_persistent_er, d_prime, connection); 2030 return; 2031 } 2032 break; 2033 2034 case SM_PH2_C1_GET_ENC_C: 2035 // already busy? 2036 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2037 // calculate m_confirm using aes128 engine - step 1 2038 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); 2039 sm_next_responding_state(connection); 2040 sm_aes128_start(setup->sm_tk, plaintext, connection); 2041 break; 2042 case SM_PH2_C1_GET_ENC_A: 2043 // already busy? 2044 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2045 // calculate confirm using aes128 engine - step 1 2046 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); 2047 sm_next_responding_state(connection); 2048 sm_aes128_start(setup->sm_tk, plaintext, connection); 2049 break; 2050 case SM_PH2_CALC_STK: 2051 // already busy? 2052 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2053 // calculate STK 2054 if (connection->sm_role){ 2055 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2056 } else { 2057 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2058 } 2059 sm_next_responding_state(connection); 2060 sm_aes128_start(setup->sm_tk, plaintext, connection); 2061 break; 2062 case SM_PH3_Y_GET_ENC: 2063 // already busy? 2064 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2065 // PH3B2 - calculate Y from - enc 2066 // Y = dm(DHK, Rand) 2067 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2068 sm_next_responding_state(connection); 2069 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2070 return; 2071 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2072 uint8_t buffer[17]; 2073 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2074 reverse_128(setup->sm_local_confirm, &buffer[1]); 2075 if (connection->sm_role){ 2076 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2077 } else { 2078 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2079 } 2080 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2081 sm_timeout_reset(connection); 2082 return; 2083 } 2084 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2085 sm_key_t stk_flipped; 2086 reverse_128(setup->sm_ltk, stk_flipped); 2087 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2088 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2089 return; 2090 } 2091 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2092 sm_key_t stk_flipped; 2093 reverse_128(setup->sm_ltk, stk_flipped); 2094 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2095 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2096 return; 2097 } 2098 case SM_RESPONDER_PH4_SEND_LTK: { 2099 sm_key_t ltk_flipped; 2100 reverse_128(setup->sm_ltk, ltk_flipped); 2101 connection->sm_engine_state = SM_RESPONDER_IDLE; 2102 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2103 return; 2104 } 2105 case SM_RESPONDER_PH4_Y_GET_ENC: 2106 // already busy? 2107 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2108 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2109 // Y = dm(DHK, Rand) 2110 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2111 sm_next_responding_state(connection); 2112 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2113 return; 2114 2115 case SM_PH3_DISTRIBUTE_KEYS: 2116 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2117 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2118 uint8_t buffer[17]; 2119 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2120 reverse_128(setup->sm_ltk, &buffer[1]); 2121 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2122 sm_timeout_reset(connection); 2123 return; 2124 } 2125 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2126 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2127 uint8_t buffer[11]; 2128 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2129 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2130 reverse_64(setup->sm_local_rand, &buffer[3]); 2131 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2132 sm_timeout_reset(connection); 2133 return; 2134 } 2135 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2136 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2137 uint8_t buffer[17]; 2138 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2139 reverse_128(sm_persistent_irk, &buffer[1]); 2140 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2141 sm_timeout_reset(connection); 2142 return; 2143 } 2144 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2145 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2146 bd_addr_t local_address; 2147 uint8_t buffer[8]; 2148 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2149 gap_advertisements_get_address(&buffer[1], local_address); 2150 reverse_bd_addr(local_address, &buffer[2]); 2151 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2152 sm_timeout_reset(connection); 2153 return; 2154 } 2155 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2156 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2157 2158 // hack to reproduce test runs 2159 if (test_use_fixed_local_csrk){ 2160 memset(setup->sm_local_csrk, 0xcc, 16); 2161 } 2162 2163 uint8_t buffer[17]; 2164 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2165 reverse_128(setup->sm_local_csrk, &buffer[1]); 2166 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2167 sm_timeout_reset(connection); 2168 return; 2169 } 2170 2171 // keys are sent 2172 if (connection->sm_role){ 2173 // slave -> receive master keys if any 2174 if (sm_key_distribution_all_received(connection)){ 2175 sm_key_distribution_handle_all_received(connection); 2176 connection->sm_engine_state = SM_RESPONDER_IDLE; 2177 sm_done_for_handle(connection->sm_handle); 2178 } else { 2179 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2180 } 2181 } else { 2182 // master -> all done 2183 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2184 sm_done_for_handle(connection->sm_handle); 2185 } 2186 break; 2187 2188 default: 2189 break; 2190 } 2191 2192 // check again if active connection was released 2193 if (sm_active_connection) break; 2194 } 2195 } 2196 2197 // note: aes engine is ready as we just got the aes result 2198 static void sm_handle_encryption_result(uint8_t * data){ 2199 2200 sm_aes128_state = SM_AES128_IDLE; 2201 2202 if (sm_address_resolution_ah_calculation_active){ 2203 sm_address_resolution_ah_calculation_active = 0; 2204 // compare calulated address against connecting device 2205 uint8_t hash[3]; 2206 reverse_24(data, hash); 2207 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2208 log_info("LE Device Lookup: matched resolvable private address"); 2209 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2210 return; 2211 } 2212 // no match, try next 2213 sm_address_resolution_test++; 2214 return; 2215 } 2216 2217 switch (dkg_state){ 2218 case DKG_W4_IRK: 2219 reverse_128(data, sm_persistent_irk); 2220 log_info_key("irk", sm_persistent_irk); 2221 dkg_next_state(); 2222 return; 2223 case DKG_W4_DHK: 2224 reverse_128(data, sm_persistent_dhk); 2225 log_info_key("dhk", sm_persistent_dhk); 2226 dkg_next_state(); 2227 // SM Init Finished 2228 return; 2229 default: 2230 break; 2231 } 2232 2233 switch (rau_state){ 2234 case RAU_W4_ENC: 2235 reverse_24(data, &sm_random_address[3]); 2236 rau_next_state(); 2237 return; 2238 default: 2239 break; 2240 } 2241 2242 switch (sm_cmac_state){ 2243 case CMAC_W4_SUBKEYS: 2244 case CMAC_W4_MI: 2245 case CMAC_W4_MLAST: 2246 { 2247 sm_key_t t; 2248 reverse_128(data, t); 2249 sm_cmac_handle_encryption_result(t); 2250 } 2251 return; 2252 default: 2253 break; 2254 } 2255 2256 // retrieve sm_connection provided to sm_aes128_start_encryption 2257 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2258 if (!connection) return; 2259 switch (connection->sm_engine_state){ 2260 case SM_PH2_C1_W4_ENC_A: 2261 case SM_PH2_C1_W4_ENC_C: 2262 { 2263 sm_key_t t2; 2264 reverse_128(data, t2); 2265 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2266 } 2267 sm_next_responding_state(connection); 2268 return; 2269 case SM_PH2_C1_W4_ENC_B: 2270 reverse_128(data, setup->sm_local_confirm); 2271 log_info_key("c1!", setup->sm_local_confirm); 2272 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2273 return; 2274 case SM_PH2_C1_W4_ENC_D: 2275 { 2276 sm_key_t peer_confirm_test; 2277 reverse_128(data, peer_confirm_test); 2278 log_info_key("c1!", peer_confirm_test); 2279 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2280 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2281 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2282 return; 2283 } 2284 if (connection->sm_role){ 2285 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2286 } else { 2287 connection->sm_engine_state = SM_PH2_CALC_STK; 2288 } 2289 } 2290 return; 2291 case SM_PH2_W4_STK: 2292 reverse_128(data, setup->sm_ltk); 2293 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2294 log_info_key("stk", setup->sm_ltk); 2295 if (connection->sm_role){ 2296 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2297 } else { 2298 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2299 } 2300 return; 2301 case SM_PH3_Y_W4_ENC:{ 2302 sm_key_t y128; 2303 reverse_128(data, y128); 2304 setup->sm_local_y = big_endian_read_16(y128, 14); 2305 log_info_hex16("y", setup->sm_local_y); 2306 // PH3B3 - calculate EDIV 2307 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2308 log_info_hex16("ediv", setup->sm_local_ediv); 2309 // PH3B4 - calculate LTK - enc 2310 // LTK = d1(ER, DIV, 0)) 2311 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2312 return; 2313 } 2314 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2315 sm_key_t y128; 2316 reverse_128(data, y128); 2317 setup->sm_local_y = big_endian_read_16(y128, 14); 2318 log_info_hex16("y", setup->sm_local_y); 2319 2320 // PH3B3 - calculate DIV 2321 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2322 log_info_hex16("ediv", setup->sm_local_ediv); 2323 // PH3B4 - calculate LTK - enc 2324 // LTK = d1(ER, DIV, 0)) 2325 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2326 return; 2327 } 2328 case SM_PH3_LTK_W4_ENC: 2329 reverse_128(data, setup->sm_ltk); 2330 log_info_key("ltk", setup->sm_ltk); 2331 // calc CSRK next 2332 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2333 return; 2334 case SM_PH3_CSRK_W4_ENC: 2335 reverse_128(data, setup->sm_local_csrk); 2336 log_info_key("csrk", setup->sm_local_csrk); 2337 if (setup->sm_key_distribution_send_set){ 2338 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2339 } else { 2340 // no keys to send, just continue 2341 if (connection->sm_role){ 2342 // slave -> receive master keys 2343 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2344 } else { 2345 // master -> all done 2346 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2347 sm_done_for_handle(connection->sm_handle); 2348 } 2349 } 2350 return; 2351 case SM_RESPONDER_PH4_LTK_W4_ENC: 2352 reverse_128(data, setup->sm_ltk); 2353 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2354 log_info_key("ltk", setup->sm_ltk); 2355 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2356 return; 2357 default: 2358 break; 2359 } 2360 } 2361 2362 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2363 static void sm_handle_random_result(uint8_t * data){ 2364 2365 switch (rau_state){ 2366 case RAU_W4_RANDOM: 2367 // non-resolvable vs. resolvable 2368 switch (gap_random_adress_type){ 2369 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2370 // resolvable: use random as prand and calc address hash 2371 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2372 memcpy(sm_random_address, data, 3); 2373 sm_random_address[0] &= 0x3f; 2374 sm_random_address[0] |= 0x40; 2375 rau_state = RAU_GET_ENC; 2376 break; 2377 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2378 default: 2379 // "The two most significant bits of the address shall be equal to ‘0’"" 2380 memcpy(sm_random_address, data, 6); 2381 sm_random_address[0] &= 0x3f; 2382 rau_state = RAU_SET_ADDRESS; 2383 break; 2384 } 2385 return; 2386 default: 2387 break; 2388 } 2389 2390 // retrieve sm_connection provided to sm_random_start 2391 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2392 if (!connection) return; 2393 switch (connection->sm_engine_state){ 2394 case SM_PH2_W4_RANDOM_TK: 2395 { 2396 // map random to 0-999999 without speding much cycles on a modulus operation 2397 uint32_t tk = little_endian_read_32(data,0); 2398 tk = tk & 0xfffff; // 1048575 2399 if (tk >= 999999){ 2400 tk = tk - 999999; 2401 } 2402 sm_reset_tk(); 2403 big_endian_store_32(setup->sm_tk, 12, tk); 2404 if (connection->sm_role){ 2405 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2406 } else { 2407 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2408 sm_trigger_user_response(connection); 2409 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2410 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2411 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2412 } 2413 } 2414 return; 2415 } 2416 case SM_PH2_C1_W4_RANDOM_A: 2417 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2418 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2419 return; 2420 case SM_PH2_C1_W4_RANDOM_B: 2421 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2422 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2423 return; 2424 case SM_PH3_W4_RANDOM: 2425 reverse_64(data, setup->sm_local_rand); 2426 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2427 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2428 // no db for authenticated flag hack: store flag in bit 4 of LSB 2429 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2430 connection->sm_engine_state = SM_PH3_GET_DIV; 2431 return; 2432 case SM_PH3_W4_DIV: 2433 // use 16 bit from random value as div 2434 setup->sm_local_div = big_endian_read_16(data, 0); 2435 log_info_hex16("div", setup->sm_local_div); 2436 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2437 return; 2438 default: 2439 break; 2440 } 2441 } 2442 2443 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2444 2445 sm_connection_t * sm_conn; 2446 hci_con_handle_t con_handle; 2447 2448 switch (packet_type) { 2449 2450 case HCI_EVENT_PACKET: 2451 switch (hci_event_packet_get_type(packet)) { 2452 2453 case BTSTACK_EVENT_STATE: 2454 // bt stack activated, get started 2455 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2456 log_info("HCI Working!"); 2457 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2458 rau_state = RAU_IDLE; 2459 sm_run(); 2460 } 2461 break; 2462 2463 case HCI_EVENT_LE_META: 2464 switch (packet[2]) { 2465 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2466 2467 log_info("sm: connected"); 2468 2469 if (packet[3]) return; // connection failed 2470 2471 con_handle = little_endian_read_16(packet, 4); 2472 sm_conn = sm_get_connection_for_handle(con_handle); 2473 if (!sm_conn) break; 2474 2475 sm_conn->sm_handle = con_handle; 2476 sm_conn->sm_role = packet[6]; 2477 sm_conn->sm_peer_addr_type = packet[7]; 2478 reverse_bd_addr(&packet[8], 2479 sm_conn->sm_peer_address); 2480 2481 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2482 2483 // reset security properties 2484 sm_conn->sm_connection_encrypted = 0; 2485 sm_conn->sm_connection_authenticated = 0; 2486 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2487 sm_conn->sm_le_db_index = -1; 2488 2489 // prepare CSRK lookup (does not involve setup) 2490 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2491 2492 // just connected -> everything else happens in sm_run() 2493 if (sm_conn->sm_role){ 2494 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2495 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2496 if (sm_slave_request_security) { 2497 // request security if requested by app 2498 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2499 } else { 2500 // otherwise, wait for pairing request 2501 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2502 } 2503 } 2504 break; 2505 } else { 2506 // master 2507 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2508 } 2509 break; 2510 2511 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2512 con_handle = little_endian_read_16(packet, 3); 2513 sm_conn = sm_get_connection_for_handle(con_handle); 2514 if (!sm_conn) break; 2515 2516 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2517 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2518 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2519 break; 2520 } 2521 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2522 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2523 break; 2524 } 2525 2526 // assume that we don't have a LTK for ediv == 0 and random == null 2527 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2528 log_info("LTK Request: ediv & random are empty"); 2529 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2530 break; 2531 } 2532 2533 // store rand and ediv 2534 reverse_64(&packet[5], sm_conn->sm_local_rand); 2535 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2536 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2537 break; 2538 2539 default: 2540 break; 2541 } 2542 break; 2543 2544 case HCI_EVENT_ENCRYPTION_CHANGE: 2545 con_handle = little_endian_read_16(packet, 3); 2546 sm_conn = sm_get_connection_for_handle(con_handle); 2547 if (!sm_conn) break; 2548 2549 sm_conn->sm_connection_encrypted = packet[5]; 2550 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2551 sm_conn->sm_actual_encryption_key_size); 2552 log_info("event handler, state %u", sm_conn->sm_engine_state); 2553 if (!sm_conn->sm_connection_encrypted) break; 2554 // continue if part of initial pairing 2555 switch (sm_conn->sm_engine_state){ 2556 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2557 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2558 sm_done_for_handle(sm_conn->sm_handle); 2559 break; 2560 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2561 if (sm_conn->sm_role){ 2562 // slave 2563 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2564 } else { 2565 // master 2566 if (sm_key_distribution_all_received(sm_conn)){ 2567 // skip receiving keys as there are none 2568 sm_key_distribution_handle_all_received(sm_conn); 2569 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2570 } else { 2571 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2572 } 2573 } 2574 break; 2575 default: 2576 break; 2577 } 2578 break; 2579 2580 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2581 con_handle = little_endian_read_16(packet, 3); 2582 sm_conn = sm_get_connection_for_handle(con_handle); 2583 if (!sm_conn) break; 2584 2585 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2586 log_info("event handler, state %u", sm_conn->sm_engine_state); 2587 // continue if part of initial pairing 2588 switch (sm_conn->sm_engine_state){ 2589 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2590 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2591 sm_done_for_handle(sm_conn->sm_handle); 2592 break; 2593 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2594 if (sm_conn->sm_role){ 2595 // slave 2596 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2597 } else { 2598 // master 2599 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2600 } 2601 break; 2602 default: 2603 break; 2604 } 2605 break; 2606 2607 2608 case HCI_EVENT_DISCONNECTION_COMPLETE: 2609 con_handle = little_endian_read_16(packet, 3); 2610 sm_done_for_handle(con_handle); 2611 sm_conn = sm_get_connection_for_handle(con_handle); 2612 if (!sm_conn) break; 2613 2614 // delete stored bonding on disconnect with authentication failure in ph0 2615 if (sm_conn->sm_role == 0 2616 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2617 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2618 le_device_db_remove(sm_conn->sm_le_db_index); 2619 } 2620 2621 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2622 sm_conn->sm_handle = 0; 2623 break; 2624 2625 case HCI_EVENT_COMMAND_COMPLETE: 2626 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2627 sm_handle_encryption_result(&packet[6]); 2628 break; 2629 } 2630 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2631 sm_handle_random_result(&packet[6]); 2632 break; 2633 } 2634 break; 2635 default: 2636 break; 2637 } 2638 break; 2639 default: 2640 break; 2641 } 2642 2643 sm_run(); 2644 } 2645 2646 static inline int sm_calc_actual_encryption_key_size(int other){ 2647 if (other < sm_min_encryption_key_size) return 0; 2648 if (other < sm_max_encryption_key_size) return other; 2649 return sm_max_encryption_key_size; 2650 } 2651 2652 static int sm_passkey_used(stk_generation_method_t method){ 2653 switch (method){ 2654 case PK_RESP_INPUT: 2655 case PK_INIT_INPUT: 2656 case OK_BOTH_INPUT: 2657 return 1; 2658 default: 2659 return 0; 2660 } 2661 } 2662 2663 /** 2664 * @return ok 2665 */ 2666 static int sm_validate_stk_generation_method(void){ 2667 // check if STK generation method is acceptable by client 2668 switch (setup->sm_stk_generation_method){ 2669 case JUST_WORKS: 2670 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2671 case PK_RESP_INPUT: 2672 case PK_INIT_INPUT: 2673 case OK_BOTH_INPUT: 2674 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2675 case OOB: 2676 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2677 case NK_BOTH_INPUT: 2678 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2679 return 1; 2680 default: 2681 return 0; 2682 } 2683 } 2684 2685 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2686 2687 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2688 sm_run(); 2689 } 2690 2691 if (packet_type != SM_DATA_PACKET) return; 2692 2693 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2694 if (!sm_conn) return; 2695 2696 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2697 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2698 return; 2699 } 2700 2701 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2702 2703 int err; 2704 2705 switch (sm_conn->sm_engine_state){ 2706 2707 // a sm timeout requries a new physical connection 2708 case SM_GENERAL_TIMEOUT: 2709 return; 2710 2711 // Initiator 2712 case SM_INITIATOR_CONNECTED: 2713 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2714 sm_pdu_received_in_wrong_state(sm_conn); 2715 break; 2716 } 2717 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2718 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2719 break; 2720 } 2721 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2722 uint16_t ediv; 2723 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2724 if (ediv){ 2725 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2726 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2727 } else { 2728 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2729 } 2730 break; 2731 } 2732 // otherwise, store security request 2733 sm_conn->sm_security_request_received = 1; 2734 break; 2735 2736 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2737 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2738 sm_pdu_received_in_wrong_state(sm_conn); 2739 break; 2740 } 2741 // store pairing request 2742 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2743 err = sm_stk_generation_init(sm_conn); 2744 if (err){ 2745 setup->sm_pairing_failed_reason = err; 2746 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2747 break; 2748 } 2749 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2750 if (setup->sm_use_secure_connections){ 2751 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2752 if (setup->sm_stk_generation_method == JUST_WORKS){ 2753 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2754 sm_trigger_user_response(sm_conn); 2755 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2756 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2757 } 2758 } else { 2759 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2760 } 2761 break; 2762 } 2763 #endif 2764 // generate random number first, if we need to show passkey 2765 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2766 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2767 break; 2768 } 2769 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2770 sm_trigger_user_response(sm_conn); 2771 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2772 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2773 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2774 } 2775 break; 2776 2777 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2778 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2779 sm_pdu_received_in_wrong_state(sm_conn); 2780 break; 2781 } 2782 2783 // store s_confirm 2784 reverse_128(&packet[1], setup->sm_peer_confirm); 2785 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2786 break; 2787 2788 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2789 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2790 sm_pdu_received_in_wrong_state(sm_conn); 2791 break;; 2792 } 2793 2794 // received random value 2795 reverse_128(&packet[1], setup->sm_peer_random); 2796 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2797 break; 2798 2799 // Responder 2800 case SM_RESPONDER_IDLE: 2801 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2802 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2803 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2804 sm_pdu_received_in_wrong_state(sm_conn); 2805 break;; 2806 } 2807 2808 // store pairing request 2809 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2810 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2811 break; 2812 2813 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2814 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2815 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2816 sm_pdu_received_in_wrong_state(sm_conn); 2817 break; 2818 } 2819 2820 // store public key for DH Key calculation 2821 reverse_256(&packet[01], setup->sm_peer_qx); 2822 reverse_256(&packet[33], setup->sm_peer_qy); 2823 2824 #ifdef USE_MBEDTLS_FOR_ECDH 2825 // validate public key 2826 mbedtls_ecp_group grp; 2827 mbedtls_ecp_group_init( &grp ); 2828 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2829 2830 mbedtls_ecp_point Q; 2831 mbedtls_ecp_point_init( &Q ); 2832 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2833 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2834 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2835 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2836 if (err){ 2837 log_error("sm: peer public key invalid %x", err); 2838 // uses "unspecified reason", there is no "public key invalid" error code 2839 sm_pdu_received_in_wrong_state(sm_conn); 2840 break; 2841 } 2842 #endif 2843 if (sm_conn->sm_role){ 2844 // responder 2845 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2846 } else { 2847 // initiator 2848 // stk generation method 2849 // passkey entry: notify app to show passkey or to request passkey 2850 switch (setup->sm_stk_generation_method){ 2851 case JUST_WORKS: 2852 case NK_BOTH_INPUT: 2853 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2854 break; 2855 case PK_INIT_INPUT: 2856 case PK_RESP_INPUT: 2857 case OK_BOTH_INPUT: 2858 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2859 break; 2860 case OOB: 2861 // TODO: implement SC OOB 2862 break; 2863 } 2864 } 2865 break; 2866 2867 case SM_SC_W4_CONFIRMATION: 2868 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2869 sm_pdu_received_in_wrong_state(sm_conn); 2870 break; 2871 } 2872 // received confirm value 2873 reverse_128(&packet[1], setup->sm_peer_confirm); 2874 2875 if (sm_conn->sm_role){ 2876 // responder 2877 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2878 } else { 2879 // initiator 2880 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2881 } 2882 break; 2883 2884 case SM_SC_W4_PAIRING_RANDOM: 2885 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2886 sm_pdu_received_in_wrong_state(sm_conn); 2887 break; 2888 } 2889 2890 // received random value 2891 reverse_128(&packet[1], setup->sm_peer_nonce); 2892 2893 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 2894 // only check for JUST WORK/NC in initiator role AND passkey entry 2895 int passkey_entry = sm_passkey_used(setup->sm_stk_generation_method); 2896 if (sm_conn->sm_role || passkey_entry) { 2897 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 2898 } 2899 2900 sm_sc_state_after_receiving_random(sm_conn); 2901 break; 2902 2903 case SM_SC_W4_DHKEY_CHECK_COMMAND: 2904 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 2905 sm_pdu_received_in_wrong_state(sm_conn); 2906 break; 2907 } 2908 // store DHKey Check 2909 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 2910 2911 // validate E = f6() 2912 sm_key56_t bd_addr_master, bd_addr_slave; 2913 bd_addr_master[0] = setup->sm_m_addr_type; 2914 bd_addr_slave[0] = setup->sm_s_addr_type; 2915 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2916 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2917 2918 uint8_t iocap_a[3]; 2919 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2920 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2921 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2922 uint8_t iocap_b[3]; 2923 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2924 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2925 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2926 sm_key_t peer_dhkey_check; 2927 if (sm_conn->sm_role){ 2928 // responder 2929 f6(peer_dhkey_check, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2930 } else { 2931 // initiator 2932 f6(peer_dhkey_check, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2933 } 2934 2935 if (0 != memcmp(setup->sm_peer_dhkey_check, peer_dhkey_check, 16) ){ 2936 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 2937 break; 2938 } 2939 2940 if (sm_conn->sm_role){ 2941 // responder 2942 // for numeric comparison, we need to wait for user confirm 2943 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 2944 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 2945 } else { 2946 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2947 } 2948 } else { 2949 // initiator 2950 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2951 } 2952 break; 2953 #endif 2954 2955 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2956 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2957 sm_pdu_received_in_wrong_state(sm_conn); 2958 break; 2959 } 2960 2961 // received confirm value 2962 reverse_128(&packet[1], setup->sm_peer_confirm); 2963 2964 // notify client to hide shown passkey 2965 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2966 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2967 } 2968 2969 // handle user cancel pairing? 2970 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2971 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2972 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2973 break; 2974 } 2975 2976 // wait for user action? 2977 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2978 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2979 break; 2980 } 2981 2982 // calculate and send local_confirm 2983 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2984 break; 2985 2986 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2987 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2988 sm_pdu_received_in_wrong_state(sm_conn); 2989 break;; 2990 } 2991 2992 // received random value 2993 reverse_128(&packet[1], setup->sm_peer_random); 2994 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2995 break; 2996 2997 case SM_PH3_RECEIVE_KEYS: 2998 switch(packet[0]){ 2999 case SM_CODE_ENCRYPTION_INFORMATION: 3000 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3001 reverse_128(&packet[1], setup->sm_peer_ltk); 3002 break; 3003 3004 case SM_CODE_MASTER_IDENTIFICATION: 3005 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3006 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3007 reverse_64(&packet[3], setup->sm_peer_rand); 3008 break; 3009 3010 case SM_CODE_IDENTITY_INFORMATION: 3011 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3012 reverse_128(&packet[1], setup->sm_peer_irk); 3013 break; 3014 3015 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3016 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3017 setup->sm_peer_addr_type = packet[1]; 3018 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3019 break; 3020 3021 case SM_CODE_SIGNING_INFORMATION: 3022 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3023 reverse_128(&packet[1], setup->sm_peer_csrk); 3024 break; 3025 default: 3026 // Unexpected PDU 3027 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3028 break; 3029 } 3030 // done with key distribution? 3031 if (sm_key_distribution_all_received(sm_conn)){ 3032 3033 sm_key_distribution_handle_all_received(sm_conn); 3034 3035 if (sm_conn->sm_role){ 3036 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3037 sm_done_for_handle(sm_conn->sm_handle); 3038 } else { 3039 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3040 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3041 if (setup->sm_use_secure_connections){ 3042 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3043 } 3044 #endif 3045 } 3046 } 3047 break; 3048 default: 3049 // Unexpected PDU 3050 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3051 break; 3052 } 3053 3054 // try to send preparared packet 3055 sm_run(); 3056 } 3057 3058 // Security Manager Client API 3059 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3060 sm_get_oob_data = get_oob_data_callback; 3061 } 3062 3063 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3064 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3065 } 3066 3067 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3068 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3069 } 3070 3071 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3072 sm_min_encryption_key_size = min_size; 3073 sm_max_encryption_key_size = max_size; 3074 } 3075 3076 void sm_set_authentication_requirements(uint8_t auth_req){ 3077 sm_auth_req = auth_req; 3078 } 3079 3080 void sm_set_io_capabilities(io_capability_t io_capability){ 3081 sm_io_capabilities = io_capability; 3082 } 3083 3084 void sm_set_request_security(int enable){ 3085 sm_slave_request_security = enable; 3086 } 3087 3088 void sm_set_er(sm_key_t er){ 3089 memcpy(sm_persistent_er, er, 16); 3090 } 3091 3092 void sm_set_ir(sm_key_t ir){ 3093 memcpy(sm_persistent_ir, ir, 16); 3094 } 3095 3096 // Testing support only 3097 void sm_test_set_irk(sm_key_t irk){ 3098 memcpy(sm_persistent_irk, irk, 16); 3099 sm_persistent_irk_ready = 1; 3100 } 3101 3102 void sm_test_use_fixed_local_csrk(void){ 3103 test_use_fixed_local_csrk = 1; 3104 } 3105 3106 void sm_init(void){ 3107 // set some (BTstack default) ER and IR 3108 int i; 3109 sm_key_t er; 3110 sm_key_t ir; 3111 for (i=0;i<16;i++){ 3112 er[i] = 0x30 + i; 3113 ir[i] = 0x90 + i; 3114 } 3115 sm_set_er(er); 3116 sm_set_ir(ir); 3117 // defaults 3118 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3119 | SM_STK_GENERATION_METHOD_OOB 3120 | SM_STK_GENERATION_METHOD_PASSKEY 3121 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3122 3123 sm_max_encryption_key_size = 16; 3124 sm_min_encryption_key_size = 7; 3125 3126 sm_cmac_state = CMAC_IDLE; 3127 dkg_state = DKG_W4_WORKING; 3128 rau_state = RAU_W4_WORKING; 3129 sm_aes128_state = SM_AES128_IDLE; 3130 sm_address_resolution_test = -1; // no private address to resolve yet 3131 sm_address_resolution_ah_calculation_active = 0; 3132 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3133 sm_address_resolution_general_queue = NULL; 3134 3135 gap_random_adress_update_period = 15 * 60 * 1000L; 3136 3137 sm_active_connection = 0; 3138 3139 test_use_fixed_local_csrk = 0; 3140 3141 // register for HCI Events from HCI 3142 hci_event_callback_registration.callback = &sm_event_packet_handler; 3143 hci_add_event_handler(&hci_event_callback_registration); 3144 3145 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3146 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3147 3148 #ifdef USE_MBEDTLS_FOR_ECDH 3149 // TODO: calculate keypair using LE Random Number Generator 3150 // use test keypair from spec initially 3151 mbedtls_ecp_keypair_init(&le_keypair); 3152 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3153 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3154 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3155 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3156 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3157 // print keypair 3158 char buffer[100]; 3159 size_t len; 3160 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3161 log_info("d: %s", buffer); 3162 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3163 log_info("X: %s", buffer); 3164 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3165 log_info("Y: %s", buffer); 3166 #endif 3167 } 3168 3169 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3170 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3171 if (!hci_con) return NULL; 3172 return &hci_con->sm_connection; 3173 } 3174 3175 // @returns 0 if not encrypted, 7-16 otherwise 3176 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3177 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3178 if (!sm_conn) return 0; // wrong connection 3179 if (!sm_conn->sm_connection_encrypted) return 0; 3180 return sm_conn->sm_actual_encryption_key_size; 3181 } 3182 3183 int sm_authenticated(hci_con_handle_t con_handle){ 3184 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3185 if (!sm_conn) return 0; // wrong connection 3186 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3187 return sm_conn->sm_connection_authenticated; 3188 } 3189 3190 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3191 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3192 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3193 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3194 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3195 return sm_conn->sm_connection_authorization_state; 3196 } 3197 3198 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3199 switch (sm_conn->sm_engine_state){ 3200 case SM_GENERAL_IDLE: 3201 case SM_RESPONDER_IDLE: 3202 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3203 sm_run(); 3204 break; 3205 default: 3206 break; 3207 } 3208 } 3209 3210 /** 3211 * @brief Trigger Security Request 3212 */ 3213 void sm_send_security_request(hci_con_handle_t con_handle){ 3214 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3215 if (!sm_conn) return; 3216 sm_send_security_request_for_connection(sm_conn); 3217 } 3218 3219 // request pairing 3220 void sm_request_pairing(hci_con_handle_t con_handle){ 3221 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3222 if (!sm_conn) return; // wrong connection 3223 3224 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3225 if (sm_conn->sm_role){ 3226 sm_send_security_request_for_connection(sm_conn); 3227 } else { 3228 // used as a trigger to start central/master/initiator security procedures 3229 uint16_t ediv; 3230 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3231 switch (sm_conn->sm_irk_lookup_state){ 3232 case IRK_LOOKUP_FAILED: 3233 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3234 break; 3235 case IRK_LOOKUP_SUCCEEDED: 3236 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3237 if (ediv){ 3238 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3239 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3240 } else { 3241 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3242 } 3243 break; 3244 default: 3245 sm_conn->sm_bonding_requested = 1; 3246 break; 3247 } 3248 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3249 sm_conn->sm_bonding_requested = 1; 3250 } 3251 } 3252 sm_run(); 3253 } 3254 3255 // called by client app on authorization request 3256 void sm_authorization_decline(hci_con_handle_t con_handle){ 3257 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3258 if (!sm_conn) return; // wrong connection 3259 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3260 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3261 } 3262 3263 void sm_authorization_grant(hci_con_handle_t con_handle){ 3264 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3265 if (!sm_conn) return; // wrong connection 3266 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3267 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3268 } 3269 3270 // GAP Bonding API 3271 3272 void sm_bonding_decline(hci_con_handle_t con_handle){ 3273 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3274 if (!sm_conn) return; // wrong connection 3275 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3276 3277 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3278 switch (setup->sm_stk_generation_method){ 3279 case PK_RESP_INPUT: 3280 case PK_INIT_INPUT: 3281 case OK_BOTH_INPUT: 3282 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3283 break; 3284 case NK_BOTH_INPUT: 3285 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3286 break; 3287 case JUST_WORKS: 3288 case OOB: 3289 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3290 break; 3291 } 3292 } 3293 sm_run(); 3294 } 3295 3296 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3297 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3298 if (!sm_conn) return; // wrong connection 3299 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3300 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3301 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3302 3303 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3304 if (setup->sm_use_secure_connections){ 3305 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3306 } 3307 #endif 3308 } 3309 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3310 if (sm_conn->sm_role){ 3311 // responder 3312 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 3313 } else { 3314 // initiator 3315 // TODO handle intiator role 3316 } 3317 } 3318 sm_run(); 3319 } 3320 3321 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3322 // for now, it's the same 3323 sm_just_works_confirm(con_handle); 3324 } 3325 3326 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3327 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3328 if (!sm_conn) return; // wrong connection 3329 sm_reset_tk(); 3330 big_endian_store_32(setup->sm_tk, 12, passkey); 3331 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3332 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3333 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3334 } 3335 sm_run(); 3336 } 3337 3338 /** 3339 * @brief Identify device in LE Device DB 3340 * @param handle 3341 * @returns index from le_device_db or -1 if not found/identified 3342 */ 3343 int sm_le_device_index(hci_con_handle_t con_handle ){ 3344 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3345 if (!sm_conn) return -1; 3346 return sm_conn->sm_le_db_index; 3347 } 3348 3349 // GAP LE API 3350 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3351 gap_random_address_update_stop(); 3352 gap_random_adress_type = random_address_type; 3353 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3354 gap_random_address_update_start(); 3355 gap_random_address_trigger(); 3356 } 3357 3358 gap_random_address_type_t gap_random_address_get_mode(void){ 3359 return gap_random_adress_type; 3360 } 3361 3362 void gap_random_address_set_update_period(int period_ms){ 3363 gap_random_adress_update_period = period_ms; 3364 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3365 gap_random_address_update_stop(); 3366 gap_random_address_update_start(); 3367 } 3368 3369 void gap_random_address_set(bd_addr_t addr){ 3370 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3371 memcpy(sm_random_address, addr, 6); 3372 rau_state = RAU_SET_ADDRESS; 3373 sm_run(); 3374 } 3375 3376 /* 3377 * @brief Set Advertisement Paramters 3378 * @param adv_int_min 3379 * @param adv_int_max 3380 * @param adv_type 3381 * @param direct_address_type 3382 * @param direct_address 3383 * @param channel_map 3384 * @param filter_policy 3385 * 3386 * @note own_address_type is used from gap_random_address_set_mode 3387 */ 3388 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3389 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3390 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3391 direct_address_typ, direct_address, channel_map, filter_policy); 3392 } 3393 3394